BENEFIT DELIVERY PARTICLE FOR TREATING SUBSTRATES
A particle for the absorption of odiferous compounds, wherein the particle comprises: (a) a solid core comprising a first hydrophobic polymer, and (b) a shell comprising a second hydrophobic polymer wherein the Tg of the first hydrophobic polymer is lower than the Tg of the second hydrophobic polymer; wherein the particles have a mean particle size of less than micron, preferably from 0.1 to 0.3 microns, wherein the odiferous compound is a malodour compound and wherein the ratio of (a):(b) is greater than 2:1.
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The present invention is concerned with core/shell particles for the absorption of malodour, wherein the particles have a specific core:shell ratio. The use of the particles has a broad application in personal care and home care applications and will be specifically disclosed herein in the context of skin (deo) and hair uses, but also applies to household care and laundry.
BACKGROUNDMany home and personal care formulations seek to deliver so-called benefit agents to substrates such as cloth, hair and skin. Encapsulation of the benefit agent in particles has been proposed as a means of enhancing delivery, which is advantageous because of the expense of some benefit agents. Delivery of particles per se can also be useful where the particles, even in the absence of specific benefit agents, confer a benefit.
Improved delivery of fragrance is one such benefit that has been highly explored over recent years. However, perceptions of “freshness” depend not only on the positive hedonics provided by fragrance but also on effective control of malodours. For example, malodour control is important on the skin, for example in the underarm, on feet, and on the scalp, as well as on hair, on laundered textiles and on hard surfaces, such as the toilet bowl or drains.
The use of polymeric particles to absorb odours and malodours in formulations is known. For example, US 2011/0021409 and WO 2009/101000 (Henkel) disclose detergents containing porous polyamide particles and their use in deodorant and antiperspirant compositions. The particles are used to absorb fragrances, and unpleasant odours. US 2009/0048365 (IFF) describes an odour absorbing capsule comprising an active ingredient and an encapsulating polymer.
However, we have found that the subsequent retention of the malodour compounds is an area where improvement is required. Often, known particles readily re-release the malodour compounds, along with fragrance compounds.
EP 1 533 365A (IFF) discloses a process for imparting a fragrance to and/or eliminating a malodour from a surface using particles comprising a polymer (preferably ethylene-vinyl acetate copolymer, ethylcellulose, polystyrene or PMMA) having a free volume (which is effected by holes present in the polymer).
US 2011/059179 (Shefer et al) discloses a controlled delivery system for malodour management, which works by absorbing and neutralizing the malodour and releasing an odorous substance to counteract the malodour. The particles have a hydrophobic core and a film forming hydrophilic surface.
EP 1 541 121A (Rohm & Haas) describes a system for releasing active ingredients from a composition comprising oil absorbing polymers and a coating comprising water sensitive, surface active polymers. The oil absorbing polymers have an average particle diameter of 20 to 1000 nm.
Many of these known particles suffer from agglomeration over time, when incorporated into home care and personal care formulations.
Copending WO02014/079745 (Unilever) has as example 2 a particle with a polybutylmethacrylate (lower Tg) core and a polymethylmethacrylate (higher Tg) shell formed on the preformed core from example 1. The shell forms on the outside of the core and so the material with higher Tg forms the shell. The reference to inner shell in the title of example 2 is because in example 3 a second polymethyl methacrylate (high Tg) shell is applied over it with a deposition aid.
We have now found that particles having a hydrophobic shell as well as a hydrophobic core, wherein the Tg of the shell is higher than that of the core, are capable of superior absorption and retention of malodour compounds; as well as absorption of perfume in the product then release of perfume after application. The particles can be successfully incorporated into compositions without causing agglomeration problems.
BRIEF DESCRIPTION OF THE INVENTIONAccordingly, the present invention provides a particle for the absorption of odiferous compounds, wherein the particle comprises:
(a) a solid core comprising a first hydrophobic polymer, and
(b) a shell comprising a second hydrophobic polymer
wherein the Tg of the first hydrophobic polymer is lower than the Tg of the second hydrophobic polymer; wherein the particles have a mean particle size of less than 1 micron, preferably from 0.15 to 0.3 microns, wherein the odiferous compound is a malodour compound and wherein the ratio of (a):(b) is greater than 2:1.
A second aspect of the present invention provides a composition comprising a particle, as defined in any preceding claim, wherein the composition comprises an active ingredient.
The Particle
The particles have an inner region, typically forming a “core” which provides a sink for the benefit agent and a “shell” which protects the benefit agent and regulates the flow of benefit agent into and out of the core. Thus, the particle can be a carrier which controls thermodynamic (rather than kinetic) partition of the benefit agent between the interior region and elsewhere. This is particularly advantageous where late stage addition of perfume is required as the particles and the perfume may be dosed into the product separately.
Optionally, further shells may be present, such as second and third outer shells, and so on, preferably a second shell.
Optionally, the particle comprises, a surface modification, preferably a deposition aid. In particularly preferred embodiments the deposition aid is substantive to proteinaceous, cellulosic, polyester or polyamide surfaces. By use of such a deposition aid, the efficiency of delivery to a specific substrate may be enhanced.
Where present, the surface modification will be present on the outer shell, such as where an optional further shell is present.
The particles may be formed from an emulsion or miniemulsion process.
The particles have an average diameter of less than 1 micron, preferably an average diameter of from 0.1 to 0.3 microns, more preferably from 0.15 to 0.3 microns.
As the particles can be small, especially below 500 nm, they do not require suspending agents and thereby simplify product formulation and enable the production of clear/transparent products. Miniemulsion particles can be a small as 50 nm. A further benefit of small particles is that they are less visible in clear products. Another useful benefit is that sizes below 500 nm favour deposition on fibrous substrates and can allow formulation without the need for suspending and/or structuring systems.
DETAILED DESCRIPTION OF THE INVENTIONThe particles are further described below.
The Second Hydrophobic Polymer
The second hydrophobic polymer has a higher glass transition temperature (Tg) than the first hydrophobic polymer thus providing a hard outer shell over a softer inner core. This provides a shell that provides mechanical stability to the particle and prevents film formation from the core lower Tg material and prevent aggregation of the core material, which is particularly likely to happen in the presence of surfactant and solvent based formulations. The glass transition temperature is preferably greater than 100° C., more preferably greater than 120° C.
The second hydrophobic polymer preferably comprises a polyurea or a polyurethane, preferably polyurethane. Preferred polyurethanes are formed from polyisocyanates with diols and cross-linked with polyamines or polyols. Where the polyisocyanate is a diisocyanate, preferred diisocyanates may be linear aliphatic, cycloaliphatic or aromatic, preferably aromatic or cycloaliphatic.
Suitable, aromatic polyisocyanates comprise, but are not limited to, 2,4- and 2,6-toluene diisocyanate, naphthalene diisocyanate, diphenyl methane diisocyanate and triphenyl methane-p,p′p″-trityl triisocyanate, polymethylene polyphenylene isocyanate, 2,4,4′-diphenylether triisocyanate, 3,3′-dimethyl-4,4′-diphenyl diisocyanate, 3,3′-dimethoxy-4,4′diphenyl diisocyanate, and 4,4′4″-triphenylmethane triisocyanate.
Suitable aliphatic polyisocyanates comprise, but are not limited to dicyclohexylmethane 4,4′-diisocyanate, hexamethylene-1,6-diisocyanate, isophorone diisocyanate, trimethyl-hexamethylene diisocyanate, trimer of hexamethylenel, 6-diisocyanate, trimer of isophorone diisocyanate, 1,4-cyclohexane diisocyanate, urea of hexamethylene diisocyanate, trimethylene diisocyanate, propylene-1,2-diisocyanate and butylenes-1,2-diisocyanate and mixtures thereof.
The preferred isocyanate materials are: 2,4- and 2,6-toluene diisocyanate and isophorone diisocyanate, most preferably isophorone diisocyanate.
The co-monomer used in the step-growth polymerisation is typically a diol or a diamine.
Suitable diols can comprise, but are not limited to, low molecular weight polymers such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butane diol, neopentyl glycol, 1,6-hexanediol, dipropylene glycol, cyclohexyl-1,4-dimethanol, 1,8-octanediol; high molecular weight polyols such as polyethylene glycol, polypropylene glycols, polytetramethylene glycols (PTMG) having average molecular weight in the range of 200 to 2000, polyester diols, diols containing carboxyl groups such as dimethylol propionic acid (DMPA) and dimethylol butanoic acid (DMBA) and mixtures thereof.
The preferred diol materials are ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butane diol, neopentyl glycol, 1,6-hexanediol, and dipropylene glycol. The more hydrophobic diols (particularly 1,4-butanediol, 2,3-butane diol, neopentyl glycol and 1,6-hexanediol) are preferred as it is generally easier to get a stable emulsion with these materials and thereby a more efficient polymerisation.
Suitable diamines can comprise amines such as ethylene diamine (EDA), phenylene diamine, toluene diamine, hexamethylene diamine, diethylenetriamine, tetraethylene pentaamine, pentamethylene hexamine, 1,6-hexane diamine, Methylene tetramine, 2,4-diamino-6-methyl-1,3,5triazine 1,2-diaminocyclohexane, 4,4′-diamino-diphenylmethane, 1,5-diaminonaphthalene, 2,4,4′-triaminodiphenylether, bis(hexa-methylenetriamine), 1,4,5,8-tetraaminoanthraquinone, isophorone diamine, diamino propane and diaminobutane, and mixtures thereof. Polymeric amines may also be used, for example Jeffamines (polyether amine) and poly(ethyleneimine).
The preferred diamine materials are ethylene diamine and 1,6-hexane diamine.
Mole ratios of the co-monomers are preferably selected such that the water soluble monomer is present in up to 10 mol % excess over the oil soluble co-monomer, preferably 1 to 8 mol % excess, more preferable 2 to 5 mol % excess. It is believed that this ensures complete reaction of isocyanate monomer.
Cross-Linking Agents for the Shell
Cross-linking agents advantageously improve the properties of the shell. Many cross-linking agents suitable for use in step-growth polymerisation are known. Cross-linking agents significantly reduce the leakage of benefit agents from the particles. Cross-linking agents are preferably polyamines and polyols.
Preferred amine-functional cross-linking agents contains more than two amine functionalities such as tetraethylene pentamine, triethylene tetraamine, 2,4,4′-triaminodiphenylether, bis(hexamethylene triamine), 1,4,5,8-tetraamino anthraquinone and diethylene triamine (DETA), and mixtures thereof.
Preferred alcohol-functional cross-linking agents contain more than two alcohol functionalities such as glycerol, pentaerythritol, and 1,1,1 trihydroxmethylpropane.
Particularly preferred cross-linking agents are polyphenylisocyanate and 1,1,1-trihydroxmethylpropane.
The preferred levels of cross-linking agent are 1 to 50 mol %, more preferably 2 to 35 mol % of the step-growth monomers.
The First Hydrophobic Polymer
The particles have a solid core comprising a first hydrophobic polymer. The first hydrophobic polymer has a lower Tg than the second hydrophobic polymer. The glass transition temperature (Tg) is preferably less than 80° C., more preferably less than 70° C. The first hydrophobic polymer is a rubbery polymer. The molecular weight is preferably at least 50,000 g/mol, such as 50,000 to 10,000, 000 g/mol, preferably from 100,000 to 7000,000 g/mol.
The core preferably comprises a polyacrylate polymer. Preferred polyacrylate polymers are polybutyl methacrylate, polybenzyl methacrylate, poly lauryl methacrylate, poly-2-hydroxyethyl methacrylate, poly-2-hydroxypropyl methacrylates and mixtures thereof.
Free-radical polymerisation (FRP) is a suitable method of chain-growth polymerisation. In FRP a mono-functional monomer is polymerised in the presence of free-radical initiator and, optionally, a chain transfer agent. Chain transfer agents can act to reduce the average molecular weight of the final polymer.
The use of a separate chain transfer agent and an initiator is preferred. However, some molecules can perform both these functions.
The free-radical initiator can be any molecule known to initiate free-radical polymerisation such as azo-containing molecules, persulfates, redox initiators, peroxides, benzyl ketones. These initiators may be activated via thermal, photolytic or chemical means. Thermal activation is preferred.
Examples of suitable initiators include but are not limited to 2,2′-azobisisobutyronitrile (AIBN), azobis(4-cyanovaleric acid), benzoyl peroxide, cumylperoxide, 1-hydroxy-cyclohexyl phenyl ketone, hydrogen peroxide/ascorbic acid.
So-called ‘iniferters’ such as benzyl-N,N-diethyldithio-carbamate can also be used.
In some cases, more than one initiator may be used.
The preferred initiators are: 2,2′-Azobis(2-methylbutyro-nitrile), 2,2′-Azobis(2.4-dimethyl valeronitrile), 1,1′-Azobis(cyclohexane-1-carbonitrile) and t-butyl hydro-peroxide and t-butyl hydro-peroxide/ascorbic acid as these minimise the production of unwanted bi-products.
Preferably, the residue of the initiator in a free-radical polymerisation comprises 0 to 5 wt %, preferably 0.01 to 5 wt % and especially 0.01 to 3% wt %, of the resulting copolymer based on the total weight of the monomers.
Monomers for the chain-growth polymerisation may comprise any carbon-carbon unsaturated (or cyclic) compound which can form an addition polymer, e.g. vinyl and allyl compounds. The mono-functional monomer may be hydrophilic, hydrophobic, amphiphilic, anionic, cationic, neutral or zwitterionic in nature. Thus, the mono-functional monomer may be selected from but not limited to monomers such as vinyl acids, vinyl acid esters, vinyl aryl compounds, vinyl acid anhydrides, vinyl amides, vinyl ethers, vinyl amines, vinyl aryl amines, vinyl nitriles, vinyl ketones, and derivatives of the aforementioned compounds as well as corresponding allyl variants thereof.
Other suitable mono-functional monomers for the chain-growth polymer include hydroxyl-containing monomers and monomers which can be post-reacted to form hydroxyl groups, acid-containing or acid functional monomers, zwitterionic monomers and quaternised amino monomers.
Oligomeric or oligo-functionalised monomers may also be used, especially oligomeric (meth)acrylic acid esters such as mono(alk/aryl) (meth)acrylic acid esters of oligo[alkyleneglycol] or oligo[dimethylsiloxane] or any other mono-vinyl or allyl adduct of a low molecular weight oligomer. Mixtures of more than one monomer may also be used.
Preferred vinyl acids and derivatives thereof include (meth)acrylic acid and acid halides thereof such as (meth)acryloyl chloride.
Preferred vinyl acid esters and derivatives thereof include C1-20 alkyl(meth)acrylates (linear & branched) such as methyl (meth)acrylate, stearyl (meth)acrylate and 2-ethyl hexyl (meth)acrylate, aryl(meth)acrylates such as benzyl (meth)acrylate.
Hydrophobic monomers include: vinyl aryl compounds such as styrene and vinylbenzyl chloride; (meth)acrylic acid esters such as mono-t-butylaminoethyl (meth)acrylate, C1-20 alkyl(meth)acrylates (linear & branched), aryl(meth) acrylates such as benzyl methacrylate; oligomeric (meth)acrylic acid esters such as mono(alk/aryl)oxyoligo-[dimethylsiloxane (meth)acrylate] and tri(alkyloxy)-silylalkyl (meth)acrylates such as trimethoxysilylpropyl-(meth)acrylate.
Functional monomers, i.e. monomers with reactive pendant groups which can be post or pre-modified with another moiety can also be used such as glycidyl (meth)acrylate, trimethoxysilylpropyl(meth)acrylate, (meth)acryloyl chloride, maleic anhydride, hydroxyalkyl (meth)acrylates, (meth)acrylic acid, vinylbenzyl chloride, activated esters of (meth)acrylic acid such as N-hydroxysuccinamido (meth)acrylate and acetoxystyrene.
The copolymer may contain unreacted polymerisable groups from the multifunctional monomer.
Especially preferred monomers for chain growth polymerisation are: C1-C20 linear or branched, alkyl, alkaryl or aryl acrylates and methacrylates.
Ratio of Step-Growth to Chain Growth Polymer:
The weight percentage of step growth polymer in the combined step growth and chain growth polymers comprising the particle is typically 10% to 99%, preferably 15% to 80%, more preferably 25% to 75%.
Cross-linking Agents for Chain-Growth Polymerisation:
Cross-linking agents can be used to modify the properties of the chain-growth polymer. Suitable materials comprise a molecule containing at least two vinyl groups that may be polymerised. The molecule may be hydrophilic, hydrophobic, amphiphilic, neutral, cationic, zwitterionic or oligomeric. Examples include di- or multivinyl esters, di- or multivinyl amides, di- or multivinyl aryl compounds and di- or multivinyl alk/aryl ethers. Typically, in the case of oligomeric or multifunctional branching agents, a linking reaction is used to attach a polymerisable moiety to a di- or multifunctional oligomer or a di- or multifunctional group. The brancher may itself have more than one branching point, such as ‘T’-shaped divinylic oligomers. In some cases, more than one multifunctional monomer may be used.
Macro cross-linkers or macro branchers (multifunctional monomers typically having a molecular weight of at least 1000 Daltons) are generally formed by linking a polymerisable moiety, such as a vinyl or aryl group, to a pre-formed multifunctional polymer via a suitable linking unit such as an ester, an amide or an ether. Examples of suitable polymers include di-functional poly(alkylene oxides) such as poly(ethyleneglycol) or poly(propylene glycol), silicones such as poly(dimethyl-siloxane)s, polymers formed by ring-opening polymerisation such as poly(caprolactone) or poly(caprolactam) or poly-functional polymers formed via living polymerisation such as poly(1,4-butadiene).
Preferred macro branchers include poly(ethyleneglycol) di(meth)acrylate, poly(propyleneglycol) di(meth)acrylate, (meth)acryloxypropyl-terminated poly (dimethylsiloxane), poly(caprolactone) di(meth)acrylate and poly(caprolactam) di(meth)acrylamide.
The corresponding allyl monomers to those listed above can also be used where appropriate.
Preferred multifunctional monomers include but are not limited to divinyl aryl monomers such as divinyl benzene; (meth)acrylate diesters such as glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, propyleneglycol di(meth)acrylate and 1,3-butylenedi(meth)acrylate; oligoalkylene oxide di(meth)acrylates such as tetra ethyleneglycol di(meth)acrylate, oligo(ethyleneglycol) di(meth)acrylate and oligo(propyleneglycol) di(meth)-acrylate; divinyl acrylamides such as methylene bis-acrylamide; silicone-containing divinyl esters or amides such as (meth)acryloxypropyl-terminated oligo (dimethyl-siloxane); divinyl ethers such as oligo (ethyleneglycol)-divinyl ether; and tetra- or tri-(meth)acrylate esters such as pentaerythritol tetra-(meth)acrylate, trimethylolpropane tri(meth)acrylate or glucose di- to penta(meth)acrylate. Further examples include vinyl or allyl esters, amides or ethers of pre-formed oligomers formed via ring-opening polymerisation such as oligo(caprolactam) or oligo-(caprolactone), or oligomers formed via a living polymerisation technique such as oligo(1,4-butadiene).
Especially preferred cross-linkers are divinyl benzene, ethylene glycol di(meth)acrylate and trimethylolpropane tri(meth)acrylate.
Levels of cross-linker are typically 0 to 75, preferably 0.0001 to 50, more preferably 0.0001 to 25 mol %.
The malodour Compounds
The particles are effective at absorption and retention of malodour compounds. Effective malodour retention is the efficient and prolonged association or entrapment of the malodour materials by the particles regardless of changes in the external environmental conditions (for example, temperature, humidity) or physical shear.
The particles are particularly effective against malodour compounds, particularly those found in home care and personal care environments, such as toilets, skin, floors and bathrooms. Preferably, the malodour compounds are those commonly found in sweat.
For example, volatile fatty acids (VFAs) and electrolytes such as isovaleric acid, 3-methyl-2-hexenoic acid and 4-methyloctanoic acid. Other common classes of malodour compound include sulfur compounds for example hydrogen sulphide, methyl mercaptans, dimethyl sulphide, 3-mercapto-2-methyl-butan-1-ol and 3-mercapto-3-methylhexan-1-ol, ammonia and amines for example trimethylamine, putrescene (1,4-diaminobutane), indole, skatole (3-methyliondole), pyrazine; aldehydes, for example acrolein and butanal, alcohols for example oct-1-en-3-ol, ketones for example oct-1-en-3-one.
The particles are capable of superior absorption and retention of malodour compounds; as well as absorption of perfume in the product then release of perfume after application. The particles retain the malodour compounds, but readily re-release fragrance compounds.
The Optional Benefit Agent
Various benefit agents can be incorporated into the particles. Preferred benefit agents provide a skin or hair related benefit. In the alternative benefit agents may be in the laundry field, for example fabric care agents, and benefit agents which provide a benefit to a laundry wash and/or rinse medium.
The benefit agent may be a hydrophobic material, for example, fragrance, anti-aging agents, anti-oxidants, vitamins, anti-bacterial agents, anti-inflammatory actives, skin conditioning agents, sunscreens etc.
Suitable benefit agents include perfume raw materials, silicone oils, waxes, hydrocarbons, higher fatty acids, essential oils, lipids, skin coolants, vitamins, sunscreens, antioxidants, glycerine, malodour reducing agents, odour controlling materials, softening agents, insect and moth repelling agents, colorants, chelants, bodyfying agents, wrinkle control agents, sanitization agents, germ control agents, skin care agents, glycerine, natural actives, antibacterial actives, preservatives, antiperspirant actives, chemosensates, (for example menthol), sunless-tanning agents (for example dihydroxyacetone), emollients (for example sunflower oil and petrolatum) and mixtures thereof.
Preferred benefit agents are fragrance, skin care agents, anti-aging agents, anti-oxidants, vitamins, anti-bacterial agents, anti-inflammatory actives, skin conditioning agents, anti-perspirants, sunscreens and mixtures thereof.
Skin
For skin compositions the preferred benefit agents include one or more of fragrances, skin lightening agents, skin conditioning agents, for example 12-hydroxy stearic acid, antimicrobials, oils and insect repellents.
Antimicrobials
Preferred antimicrobials include quaternary ammonium compounds, biguanides (polyhexamethylene biguanide), phenols (e.g. Triclosan™, thymol), essential oils (such as Tea Tree Oil and Thyme Oil), climbazole, octapyrox, ketoconizole, zinc pyrithione and mixtures thereof.
Suncreens and Skin Lightening
Preferred sunscreens and/or skin lightening agents are vitamin B3 compounds. Suitable vitamin B3 compounds are selected from niacin, niacinamide, nicotinyl alcohol, or derivatives or salts thereof. Other vitamins which act as skin lightening agents can be advantageously included in the skin lightening composition to provide for additional skin lightening effects. These include vitamin B6, vitamin C, vitamin A or their precursors. Mixtures of the vitamins can also be employed in the compositions. An especially preferred additional vitamin is vitamin B6. Other non-limiting examples of skin lightening agents useful herein include adapalene, aloe extract, ammonium lactate, arbutin, azelaic acid, butyl hydroxy anisole, butyl hydroxy toluene, citrate esters, deoxyarbutin, 1,3 diphenyl propane derivatives, 2, 5 di-hydroxyl benzoic acid and its derivatives, 2-(4-acetoxyphenyl)-1,3-dithane, 2-(4-hydroxylphenyl)-1,3 diethane, ellagic acid, gluc-pyranosyl-1-ascorbate, gluconic acid, glycolic acid, green tea extract, 4-Hydroxy-5-methyl-3[2H]-furanone, hydroquinone, 4-hydroxyanisole and its derivatives, 4-hydroxy benzoic acid derivatives, hydroxycaprylic acid, inositol ascorbate, kojic acid, lactic acid, lemon extract, linoleic acid, magnesium ascorbyl phosphate, 5-octanoyl salicylic acid, 2,4 resorcinol derivatives, 3,5 resorcinol derivatives, salicylic acid, 3,4,5 trihydroxybenzyl derivatives, and mixtures thereof. Preferred sunscreens are 2-ethylhexyl-p-methoxycinnamate, butyl methoxy dibenzoylmethane, 2-hydroxy-4-methoxybenzophenone, octyl dimethyl-p-aminobenzoic acid and mixtures thereof. Particularly preferred sunscreen is chosen from 2-ethyl hexyl-p-methoxycinnamate, 4,-t-butyl-4′-methoxydibenzoyl-methane or mixtures thereof. Other conventional sunscreen agents that are suitable for use in skin lightening compositions include 2-hydroxy-4-methoxybenzophenone, octyldimethyl-p-aminobenzoic acid, digalloyltrioleate, 2,2-dihydroxy-4-methoxybenzophenone, ethyl-4-(bis(hydroxypropyl)) aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate, glyceryl-p-aminobenzoate, 3,3,5-trimethylcyclohexyl-salicylate, methylanthranilate, p-dimethyl-aminobenzoic acid or aminobenzoate, 2-ethylhexyl-p-dimethyl-amino-benzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2-(p-dimethylaminophenyl)-5-sulfonic benzoxazoic acid and mixtures of these compounds.
Examples of particular sunscreen payloads are UV-B filters such as 2-ethylhexyl-4-methoxycinnamate (sold under the trade name Parsol MCX by DSM), and UV-A filters such as benzophenone or 4-tert-butyl-4′-methoxydibenzoylmethane (Avobenzone, sold under the trade name Parsol 1789 by DSM).
Antioxidants, Anti-Ageing Actives and Anti-Inflammatory Actives
Suitable actives include Retinol (Vitamin A), ascorbyl palmitate (Vitamin C palmitate), Cholecalciferol (Vitamin D3), tocopheryl (Vitamin E) acetate, Vitamin E palmitate, linoleic acid (Vitamin F), carotenoids such as beta-carotene and curcumin, phenols and polyphenols (e.g. resveratrol).
Preferred anti-oxidants include vitamin E, retinol, antioxiants based on hydroxytoluene such as lrganox™ or commercially available antioxidants such as the Trollox™ series.
Preferred examples in the laundry field include flavours and fragrances, enzymes, antifoams, fluorescer, shading dyes and/or pigments, conditioning agents (for example water-insoluble quaternary ammonium materials and/or silicones), sunscreens, ceramides, antioxidants, reducing agents, sequestrants, colour care additives, density matching polymers, photo-bleaches, lubricants, unsaturated oils, emollients/moisturiser and antimicrobial agents.
Perfumes
Perfume (also called herein fragrance) materials (which include pro-fragrances) are a particularly preferred benefit agent.
The pro-fragrance can, for example, be a food lipid. Food lipids typically contain structural units with pronounced hydrophobicity. The majority of lipids are derived from fatty acids. In these ‘acyl’ lipids the fatty acids are predominantly present as esters and include mono-, di-, triacyl glycerols, phospholipids, glycolipids, diol lipids, waxes, sterol esters and tocopherols. In their natural state, plant lipids comprise antioxidants to prevent their oxidation. While these may be at least in part removed during the isolation of oils from plants some antioxidants may remain. These antioxidants can be pro-fragrances. In particular, the carotenoids and related compounds including vitamin A, retinol, retinal, retinoic acid and provitamin A are capable of being converted into fragrant species including the ionones, damascones and damscenones. Preferred pro-fragrance food lipids include olive oil, palm oil, canola oil, squalene, sunflower seed oil, wheat germ oil, almond oil, coconut oil, grape seed oil, rapeseed oil, castor oil, corn oil, cottonseed oil, safflower oil, groundnut oil, poppy seed oil, palm kernel oil, rice bran oil, sesame oil, soybean oil, pumpkin seed oil, jojoba oil and mustard seed oil. Perfume components which are odiferous materials are described in further detail below.
The perfume is typically present in an amount of from 10 to 85 wt % of the particle, preferably from 15 to 75 wt % of the particle. The perfume suitably has a molecular weight of from 50 to 500 Dalton. Pro-fragrances can be of higher molecular weight, being typically 1 to 10 kDa.
Useful components of the perfume include materials of both natural and synthetic origin. They include single compounds and mixtures. Specific examples of such components may be found in the literature, e.g., in Fenaroli's Handbook of Flavour Ingredients, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M. B. Jacobs, edited by Van Nostrand; or Perfume and Flavour Chemicals by S. Arctander 1969, Montclair, N.J. (USA). These substances are well known to the person skilled in the art of perfuming, flavouring, and/or aromatizing consumer products, i.e., of imparting an odour and/or a flavour or taste to a consumer product traditionally perfumed or flavoured, or of modifying the odour and/or taste of said consumer product.
By perfume in this context is not only meant a fully formulated product fragrance, but also selected components of that fragrance, particularly those which are prone to loss, such as the so-called ‘top notes’.
Top notes are defined by Poucher (Journal of the Society of Cosmetic Chemists 6(2):80[1955]). Examples of well-known top-notes include citrus oils, linalool, linalyl acetate, lavender, dihydromyrcenol, rose oxide and cis-3-hexanol. Top notes typically comprise 15 to 25 wt % of a perfume composition and in those embodiments which contain an increased level of top-notes it is envisaged at that least 20 wt % would be present within the particle.
Typical perfume components which it is advantageous to employ in the particles and compositions include those with a relatively low boiling point, preferably those with a boiling point of less than 300, preferably 100 to 250° C.
It is also advantageous to encapsulate perfume components which have a low LogP (i.e. those which will be partitioned into water), preferably with a LogP of less than 3.0. These materials, of relatively low boiling point and relatively low LogP have been called the “delayed blooming” perfume ingredients and include the following materials:
Allyl Caproate, Amyl Acetate, Amyl Propionate, Anisic Aldehyde, Anisole, Benzaldehyde, Benzyl Acetate, Benzyl Acetone, Benzyl Alcohol, Benzyl Formate, Benzyl Iso Valerate, Benzyl Propionate, Beta Gamma Hexenol, Camphor Gum, Laevo-Carvone, d-Carvone, Cinnamic Alcohol, Cinamyl Formate, Cis-Jasmone, cis-3-Hexenyl Acetate, Cuminic Alcohol, Cyclal C, Dimethyl Benzyl Carbinol, Dimethyl Benzyl Carbinol Acetate, Ethyl Acetate, Ethyl Aceto Acetate, Ethyl Amyl Ketone, Ethyl Benzoate, Ethyl Butyrate, Ethyl Hexyl Ketone, Ethyl Phenyl Acetate, Eucalyptol, Eugenol, Fenchyl Acetate, Flor Acetate (tricyclo Decenyl Acetate), Frutene (tricycico Decenyl Propionate), Geraniol, Hexenol, Hexenyl Acetate, Hexyl Acetate, Hexyl Formate, Hydratropic Alcohol, Hydroxycitronellal, Indone, Isoamyl Alcohol, Iso Menthone, Isopulegyl Acetate, Isoquinolone, Ligustral, Linalool, Linalool Oxide, Linalyl Formate, Menthone, Menthyl Acetphenone, Methyl Amyl Ketone, Methyl Anthranilate, Methyl Benzoate, Methyl Benyl Acetate, Methyl Eugenol, Methyl Heptenone, Methyl Heptine Carbonate, Methyl Heptyl Ketone, Methyl Hexyl Ketone, Methyl Phenyl Carbinyl Acetate, Methyl Salicylate, Methyl-N-Methyl Anthranilate, Nerol, Octalactone, Octyl Alcohol, p-Cresol, p-Cresol Methyl Ether, p-Methoxy Acetophenone, p-Methyl Acetophenone, Phenoxy Ethanol, Phenyl Acetaldehyde, Phenyl Ethyl Acetate, Phenyl Ethyl Alcohol, Phenyl Ethyl Dimethyl Carbinol, Prenyl Acetate, Propyl Bornate, Pulegone, Rose Oxide, Safrole, 4-Terpinenol, Alpha-Terpinenol, and /or Viridine.
It is commonplace for a plurality of perfume components to be present in a formulation. E.g. four or more, preferably five or more, more preferably six or more or even seven or more different perfume components from the list given of delayed blooming perfumes given above present in the particles.
The compositions may contain both encapsulated fragrance and non-encapsulated fragrance. The combined weight of encapsulated and non-encapsulated fragrance is often at least 0.5 wt % of the total composition and in many suitable compositions is up to 8 wt %, and in many desirable embodiments is from 1 to 5 wt %. The weight of non-encapsulated fragrance is commonly at least 0.1 wt % of the total composition, often at least 0.2 wt % and particularly at least 0.4 wt %. In many desirable embodiments, the compositions contain up to 2 wt % non-encapsulated fragrance based on the total composition (propellant-free). The weight ratio of the encapsulated fragrance to non-encapsulated fragrance is at the discretion of the formulator, but in practice is often at least 1:10, in many compositions at least 1:5 and in some preferred compositions at least 1:3. Said weight ratio is commonly up to 10:1, often up to 5:1 and in at least some desirable compositions is up to 3:1.
Subject to the aforementioned constraints, the respective fragrances can comprise any perfume component or preferably a mixture of components. Each fragrance commonly comprises at least 6 components, particularly at least 12 components and often at least 20 components.
The perfume component oils herein commonly have a ClogP value of at least 0.1 and often at least 0.5.
Representative fragrance oils having a boiling point of below 250° C. at 1 bar pressure include the following materials:-anethol, methyl heptine carbonate, ethyl aceto acetate, para cymene, nerol, decyl aldehyde, para cresol, methyl phenyl carbinyl acetate, ionone alpha, ionone beta, undecylenic aldehyde, undecyl aldehyde, 2,6-nonadienal, nonyl aldehyde, octyl aldehyde, phenyl acetaldehyde, anisic aldehyde, benzyl acetone, ethyl-2-methyl butyrate, damascenone, damascone alpha, damascone beta, flor acetate, frutene, fructone, herbavert, iso cyclo citral, methyl isobutenyl tetrahydro pyran, iso propyl quinoline, 2,6-nonadien-1-ol, 2-methoxy-3-(2-methylpropyl)-pyrazine, methyl octine carbonate, thdecene-2-nithle, allyl amyl glycolate, cyclogalbanate, cyclal C, melonal, gamma nonalactone, cis 1,3-oxathiane-2-methyl-4-propyl, benzaldehyde, benzyl acetate, camphor, carvone, borneol, bornyl acetate, decyl alcohol, eucalyptol, linalool, hexyl acetate, iso-amyl acetate, thymol, carvacrol, limonene, menthol, iso-amyl alcohol, phenyl ethyl alcohol, alpha pinene, alpha terpineol, citronellol, alpha thujone, benzyl alcohol, beta gamma hexenol, dimethyl benzyl carbinol, phenyl ethyl dimethyl carbinol, adoxal, allyl cyclohexane propionate, beta pinene, citral, citronellyl acetate, citronellal nitrile, dihydro myrcenol, geraniol, geranyl acetate, geranyl nitrile, hydroquinone dimethyl ether, hydroxycitronellal, linalyl acetate, phenyl acetaldehyde dimethyl acetal, phenyl propyl alcohol, prenyl acetate, triplal, tetrahydrolinalool, verdox, and cis-3-hexenyl acetate.
Representative fragrance oils having a boiling point at 1 bar pressure of at least 250° C. include: ethyl methyl phenyl glycidate, ethyl vanillin, heliotropin, indol, methyl anthranilate, vanillin, amyl salicylate, coumarin, ambrox, bacdanol, benzyl salicylate, butyl anthranilate, cetalox, ebanol, cis-3-hexenyl salicylate, lilial, gamma undecalactone, gamma dodecalactone, gamma decalactone, calone, cymal, dihydro iso jasmonate, iso eugenol, lyral, methyl beta naphthyl ketone, beta naphthol methyl ether, para hydroxyl phenyl butanone, 8-cyclohexadecen-1-one, oxocyclohexadecen-2-one/habanolide, florhydral, intreleven aldehyde eugenol, amyl cinnamic aldehyde, hexyl cinnamic aldehyde, hexyl salicylate, methyl dihydro jasmonate, sandalore, veloutone, undecavertol, exaltolide/cyclopentadecanolide, zingerone, methyl cedrylone, sandela, dimethyl benzyl carbinyl butyrate, dimethyl benzyl carbinyl isobutyrate, triethyl citrate, cashmeran, phenoxy ethyl isobutyrate, iso eugenol acetate, helional, iso E super, ionone gamma methyl, pentalide, galaxolide, phenoxy ethyl propionate. The fragrances employed herein, either into the capsules or not encapsulated can comprise a pre-formed blend, either extracted from natural products, or possibly created synthetically. Representatives of such pre-formed blends include oils from: Bergamot, cedar atlas, cedar wood, clove, geranium, guaiac wood, jasmine, lavender, lemongrass, lily of the valley, lime, neroli, musk, orange blossom, patchouli, peach blossom, petitgrain or petotgrain, pimento, rose, rosemary, and thyme.
Aromatherapy
Another group of perfumes are the so-called ‘aromatherapy’ materials. These include many components also used in perfumery, including components of essential oils such as Clary Sage, Eucalyptus, Geranium, Lavender, Mace Extract, Neroli, Nutmeg, Spearmint, Sweet Violet Leaf and Valerian.
Insect Repellents
The benefit agent may also be an insect repellent material (where insect should be read broadly to include other pests which are arthropods but not strictly hexapods—for example ticks). Many of these materials overlap with the class of perfume components and some are odourless to humans or have a non-perfume odour. Commonly used repellents include: DEET (N,N-diethyl-m-toluamide), essential oil of the lemon eucalyptus (Corymbia citriodora) and its active compound p-menthane-3,8-diol (PMD), Icaridin, also known as Picaridin, D-Limonene, Bayrepel, and KBR 3023, Nepetalactone, also known as “catnip oil”, Citronella oil, Permethrin, Neem oil and Bog Myrtle. Known insect repellents derived from natural sources include: Achillea alpine, alpha-terpinene, Basil oil (Ocimum basilicum), Callicarpa americana (Beautyberry), Camphor, Carvacrol, Castor oil (Ricinus communis), Catnip oil (Nepeta species), Cedar oil (Cedrus atlantica), Celery extract (Apium graveolens), Cinnamon (Cinnamomum Zeylanicum, leaf oil), Citronella oil (Cymbopogon fleusus), Clove oil (Eugenic caryophyllata), Eucalyptus oil (70%+eucalyptol, also known as cineol), Fennel oil (Foeniculum vulgare), Garlic Oil (Allium sativum), Geranium oil (also known as Pelargonium graveolens), Lavender oil (Lavandula officinalis), Lemon eucalyptus (Corymbia citriodora) essential oil and its active ingredient p-menthane-3,8-diol (PMD), Lemongrass oil (Cymbopogon flexuosus), Marigolds (Tagetes species), Marjoram (Tetranychus urticae and Eutetranychus orientalis), Neem oil (Azadirachta indica), Oleic acid, Peppermint (Mentha×piperita), Pennyroyal (Mentha pulegium), Pyrethrum (from Chrysanthemum species, particularly C. cinerariifolium and C. coccineum), Rosemary oil (Rosmarinus officinalis), Spanish Flag Lantana camara (Helopeltis theivora), Solanum villosum berry juice, Tea tree oil (Melaleuca alternifolia) and Thyme (Thymus species) and mixtures thereof.
The solid body optionally comprises a carrier oil (also referred to herein as a diluent). It will be clear to a skilled person which oils are suitable for use with a certain benefit composition. The carrier oils are hydrophobic materials that are miscible in the benefit agent materials. Suitable oils are those having reasonable affinity for the benefit agent. Suitable materials include, but are not limited to triglyceride oil, mono and diglycerides, mineral oil, silicone oil, diethyl phthalate, polyalpha olefins, castor oil and isopropyl myristate. Preferably, the oil is a triglyceride oil, most preferably a capric/caprylic triglyceride oil.
Optional Surface Modifications and Deposition Aids
Surface modifications, including deposition aids modify the properties of the exterior of the particle. One particular benefit which can be obtained with these materials is to make the particle more substantive to a desired substrate. Desired substrates include cellulosics (including cotton), polyesters (including those employed in the manufacture of polyester fabrics) and protein-containing substrates (such as skin and hair). Deposition aids are preferably selected from non-hydrolysable cotton-substantive polymers, hydrolysable cotton-substantive polymers, polyester-substantive polymers and polymers that are substantive to skin and hair.
Preferred polysaccharide polymers, whether hydrolysable or not may be derived from a broad range of polysaccharides. Preferably, the polysaccharide is selected from the group consisting of: tamarind gum (preferably consisting of xyloglucan polymers), guar gum, locust bean gum (preferably consisting of galactomannan polymers), and other industrial gums and polymers, which include, but are not limited to, Tara, Fenugreek, Aloe, Chia, Flaxseed, Psyllium seed, quince seed, xanthan, gellan, welan, rhamsan, dextran, curdlan, pullulan, scleroglucan, schizophyllan, chitin, hydroxyalkyl cellulose, arabinan (preferably from sugar beets), de-branched arabinan (preferably from sugar beets), arabinoxylan (preferably from rye and wheat flour), galactan (preferably from lupin and potatoes), pectic galactan (preferably from potatoes), galactomannan (preferably from carob, and including both low and high viscosities), glucomannan, lichenan (preferably from icelandic moss), mannan (preferably from ivory nuts), pachyman, rhamnogalacturonan, acacia gum, agar, alginates, carrageenan, chitosan, clavan, hyaluronic acid, heparin, inulin, cellodextrins, cellulose, cellulose derivatives and mixtures thereof.
Preferred non-hydrolysable cotton-substantive deposition aids include non-hydrolysable polysaccharides. The polysaccharide preferably has a β-1,4-linked backbone.
Preferably the polysaccharide is a cellulose, a cellulose derivative, or another β-1,4-linked polysaccharide having an affinity for cellulose, such as polymannan, polyglucan, polyglucomannan, polyxyloglucan and polygalactomannan or a mixture thereof. More preferably, the polysaccharide is selected from the group consisting of polyxyloglucan and polygalactomannan. Most preferably, the deposition aid is locust bean gum, xyloglucan, guar gum or mixtures thereof.
Preferred hydrolysable cotton-substantive deposition aids include hydrolysable polysaccharides. These comprise a polysaccharide which has been modified to render it more water soluble by means of a group covalently attached to the polysaccharide by means of hydrolysable bond. Preferred groups may for example be independently selected from one or more of acetate, propanoate, trifluoroacetate, 2-(2-hydroxy-|-oxopropoxy) propanoate, lactate, glycolate, pyruvate, crotonate, isovalerate cinnamate, formate, salicylate, carbamate, methylcarbamate, benzoate, gluconate, methanesulphonate, toluene, sulphonate, groups and hemiester groups of fumaric, malonic, itaconic, oxalic, maleic, succinic, tartaric, aspartic, glutamic, and malic acids.
Preferred amongst such hydrolysable deposition aids is cellulose mono acetate.
Suitable and preferred polyester-substantive deposition aids include phthalate containing polymers, more preferably a polymer having one or more nonionic hydrophilic components comprising oxyethylene, polyoxyethylene, oxypropylene or polyoxypropylene segments, and, one or more hydrophobic components comprising terephthalate segments. Typically, oxyalkylene segments of these deposition aids will have a degree of polymerization of from 1 to about 400, although higher levels can be used, preferably from 100 to about 350, more preferably from 200 to about 300.
One type of preferred deposition aid is a copolymer having random blocks of ethylene terephthalate and polyethylene oxide terephthalate.
The deposition aid may be straight or branched. The preferred molecular weight of the polymeric deposition aid is in the range of from about 5 kDa to about 500 kDa, preferably 10 kDa to 500 kDa, more preferably 20 kDa to 300 kDa.
Preferably, the deposition-aid polymer is present at levels such that the ratio polymer:particle solids is in the range 1:500 to 3:1, preferably 1:200 to 1:3.
Preparation Methods
Polymerisation occurs in at least two phases.
In a first suitable process, a shell is first formed by step growth polymerisation. This shell encloses and contains the reagents for the chain-growth reaction which forms the core in a later phase.
Temporal separation of these phases is accomplished by control of the reagents present and the reaction conditions.
Typically, at least one of the components of the shell-forming reaction is withheld from the initial reaction mixture and added gradually to control the progress of the reaction in the first phase.
Advantageously, the first phase of the reaction is performed under conditions in which the chain-growth reaction is inhibited. These conditions include a sufficiently low temperature (for a thermally activated reaction) or conditions of sufficiently low light (for a photo-activated reaction).
Once the shell-forming reaction has proceeded sufficiently, the conditions are modified (for example, by raising the temperature or exposing the reaction mixture to light) to cause the reaction to form the inner region to start.
The preferred method is one in which an emulsion is formed comprising the chain-growth polymer components in a non-aqueous dispersed phase and the step-growth polymer components are at the interface between the dispersed phase and the continuous aqueous phase.
Typically the aqueous phase comprises an emulsifying agent, and one of the co-monomers for the step-growth polymer. It may also contain any diol, alcohol or amine cross-linking agent.
The disperse phase comprises the chain-growth monomer, the initiator, any isocyanate or vinyl cross-linking agents, the other co-monomer for the step growth polymer and any optional benefit agent.
The benefit agent may be present in the reaction mixture, at a level to give the benefit agent levels in the resulting particles at the levels disclosed above, although it is also possible to form “empty” particles and subsequently expose them to a benefit agent which can be adsorbed into the inner region.
Surface modification materials are generally added to the aqueous phase towards the end of the process, where, for example, further monomer(s) can be added to form further shell material and bind additional materials to the outside of the particle.
A second process of production of the particles involves firstly forming the core by a chain growth polymerisation process and secondly introduction of additional reagents to produce the shell by a second chain growth polymerisation process.
If used, the deposition aid polymer may be grafted to the particles by formation of an additional shell formed by a chain growth polymerisation process.
Emulsifying Agents
Many emulsifying agents are known for use in emulsion polymerisation. Suitable emulsifying agents for use in the polymerisation process may comprise, but are not limited to, non-ionic surfactants such as polyvinylpyrrolidone (PVP), polyethylene glycol sorbitan monolaurate (Tween 20), polyethylene glycol sorbitan monopalmitate (tween 40), polyethylene glycol sorbitan monooleate (Tween 80), polyvinyl alcohol (PVA), and poly(ethoxy)nonyl phenol, ethylene maleic anhydride (EMA) copolymer, Easy-Sperse™ (from ISP Technologies Inc.), ionic surfactants such as partially neutralized salts of polyacrylic acids such as sodium or potassium polyacrylate or sodium or potassium polymethacrylate. Brij™-35, Hypermer™ A 60, or sodium lignosulphate, and mixtures thereof.
Emulsifiers may also include, but are not limited to, acrylic acid-alkyl acrylate copolymer, poly(acrylic acid), polyoxyalkylene sorbitan fatty esters, polyalkylene co-carboxy anhydrides, polyalkylene co-maleic anhydrides, poly(methyl vinyl ether-co-maleic anhydride), poly(propylene-co-maleic anhydride), poly(butadiene co-maleic anhydride), and poly(vinyl acetate-co-maleic anhydride), polyvinyl alcohols, polyalkylene glycols, polyoxyalkylene glycols, and mixtures thereof. Preferred emulsifying agents are fatty alcohol exthoylates (particularly of the Brij™ class), salts of ether sulphates (including SLES), alkyl and alkaryl sulphonates and sulphates (including LAS and SDS) and cationic quaternary salts (including CTAC and CTAB).
It is particularly preferred that the emulsifying agent comprises a nonionic surfactant. This is believed to produce a particle which deposits better on cloth than one produced soley with an anionic surfactant emulsifier, as cloth become anionic during a wash. It is also preferred that the non-ionic surfactant is hydrophilic, so as to promote the formation of a stable mini-emulsion. The alcohol ethoxylates with more than ten moles of ethoxylation, for example Synperonic A20 (C1320EO) and Brij 58 (C16EO20), yield good results. DLS data for samples shows that as the level of surfactant increases the particle size becomes smaller, which is also advantageous. Preferably, the ratio of non-ionic to anionic emulsifier should be greater than 1:1 (i.e. non-ionic is present in excess) and the total surfactant level should be >3 wt % of the polymerisation mixture.
Co-Surfactant:
Typically a co-surfactant will be present in the dispersed phase and in the resulting particle. Suitable co-surfactants include hexadecane, cetyl alcohol, lauroyl peroxide, n-dodecyl mercaptan, dodecyl methacrylate, stearyl methacrylate, polystyrene, polydecene, mineral oils, isopropyl myristate C13-C15 alkyl benzoate and polymethyl methacrylate.
The preferred cosurfactants comprise hexadecane, polydecene and isopropyl myristate.
As a wt % of oil phase as a total, the co-surfactant is typically 0 to 20 wt %, preferably 1 to 15 wt %, more preferably 2 to 12.5 wt %.
Catalyst
Optional catalyst may be present in the dispersed phase of the emulsion. This advantageously minimises the hydrolysis of isocyanate to primary amine, which can react with further isocyanate to form polyurea during the production of polyurethane. This unwanted reaction can result in an excess of diol being left at the end of the process which can potentially lead to the formation of malodour and interfere with cross-linking reactions.
Suitable catalysts may comprise amino or organo-metalic compounds such as N,N′-dimethylaminoethanol, N,N′-dimethylcyclohexylamine, bis-(2-dimethylaminoethyl) ether, N,N′-dimethylacetylamine, diaminobicyclooctane, stannous octoate and dibutyl tin dilaurate, 1,3-bis(dimethylamino) butane, pentamethyldiethylenetriamine and mixtures thereof.
The level of catalyst is typically 0.1 to 2 wt % with respect to chain-growth monomer.
Polymerisation Conditions
As noted above, polymerisation typically occurs in at least two phases. In the earlier phase the shell is preferably formed by a reaction which, in preferred embodiments occurs at less than about 60° C., typically 15 to 55° C. In the later phase the inner region is polymerised at a preferred temperature of more than about 70° C., typically 70 to 95° C.
Both reactions are allowed to proceed for sufficiently long for polymerisation to be essentially complete, 1 to 3 hours being typical for each stage.
Deposition aid may added at the end of the later phase (preferably after cooling), when for example, further shell forming material (for example further isocyanate and co-monomer) are also added to bind the deposition aid to the outer surface of the particle by the formation of further shell material which entraps a portion of the deposition aid and leads to a “hairy” particle in which the “hair” comprises the deposition aid.
Alternatively, the deposition aid can be grafted on during an additional step chain polymerisation step.
For simple core-shell particles, the core excluding benefit agent is less than or equal to 80 wt % of mass, and the shell generally 20 wt % or greater of the mass of the particle.
Preferably the emulsion polymerisation step is a so-called “mini-emulsion” polymerisation, performed with a dispersed phase droplet size of below one micron. Sufficiently fine emulsions can be obtained by a range of methods, including sonication, and/or via high shear dynamic mixers or static mixers. Mini-emulsion products have excellent suspending properties.
Use in Products
The particles may be incorporated into a composition. These compositions may be in any physical form e.g. a solid such as a powder or granules, a tablet, a solid bar, a paste, soft solid, gel or liquid, especially, an aqueous-based liquid.
The composition is a home or personal care composition, preferably selected from a deodorant, antiperspirant, shampoo, hair conditioner, skin care, skin cleansing product, a laundry detergent, laundry conditioner, a hard surface cleaner, floor cleaner and a soft surface refresher. Most preferably, the composition is suitable for the treatment of skin and/or hair.
The composition comprises an active ingredient. The active ingredient is preferably for the treatment of skin or hair.
Particularly suitable active ingredients include surfactants, cleaning agents, emulsifiers, chelators, solvents, polymers, antiperspirants, moisturisers, humectants and emollients, antimicrobials (antibacterials and antifungals), abrasives, skin health actives, e.g. antioxidants, and mixtures thereof. More preferably the active ingredients are selected from a surfactant, a cleaning agent, a solvent, a polymer, an antiperspirant active and mixtures thereof, most preferably surfactants.
The composition may further comprise various additional ingredients known to a person skilled in the art. Such additional ingredients include but are not limited to: perfumes, chemosensates, pigments or dyes, optical brighteners, preservatives, sunscreens, emulsifiers, gelling agents, thickening agents, humectants (e.g. glycerine, sorbitol).
Surfactants
The active ingredient may be a surfactant, selected from anionic surfactant, non-ionic surfactant, cationic surfactant, zwitterionic surfactant, amphoteric surfactant and mixtures thereof.
Where the surface is hair or scalp, the composition may comprise an alkyl sulphate and/or ethoxylated alkyl sulfate anionic surfactant, preferably at a level of from 2 to 16 wt %, preferably from 3 to 14 wt %, more preferably from 4 to 10 wt %.
Preferred alkyl sulfates are C8-18 alky sulfates, more preferably C12-18 alkyl sulfates, preferably in the form of a salt with a solubilising cation such as sodium, potassium, ammonium or substituted ammonium. Examples are sodium lauryl sulfate (SLS) or sodium dodecyl sulfate (SDS).
Preferred alkyl ether sulfates are those having the formula: RO(CH2CH2O)nSO3M; wherein R is an alkyl or alkenyl having from 8 to 18 (preferably 12 to 18) carbon atoms; n is a number having an average value of greater than at least 0.5, preferably between 1 and 3; and M is a solubilising cation such as sodium, potassium, ammonium or substituted ammonium. An example is sodium lauryl ether sulfate (SLES).
A preferred ethoxylated alkyl sulfate anionic surfactant is sodium lauryl ether sulfate (SLES) having an average degree of ethoxylation of from 0.5 to 3, preferably 1 to 3.
Compositions may comprise one or more further anionic cleansing surfactants which are cosmetically acceptable and suitable for topical application to the hair.
Examples of further suitable anionic cleansing surfactants are the alkaryl sulphonates, alkyl succinates, alkyl sulphosuccinates, alkyl ether sulphosuccinates, N-alkyl sarcosinates, alkyl phosphates, alkyl ether phosphates, and alkyl ether carboxylic acids and salts thereof, especially their sodium, magnesium, ammonium and mono-, di- and triethanolamine salts. The alkyl and acyl groups generally contain from 8 to 18, preferably from 10 to 16 carbon atoms and may be unsaturated. The alkyl ether sulphosuccinates, alkyl ether phosphates and alkyl ether carboxylic acids and salts thereof may contain from 1 to 20 ethylene oxide or propylene oxide units per molecule.
Typical anionic cleansing surfactants for use in compositions include sodium oleyl succinate, ammonium lauryl sulphosuccinate, sodium lauryl ether sulphosuccinate, sodium dodecylbenzene sulphonate, triethanolamine dodecylbenzene sulphonate, lauryl ether carboxylic acid and sodium N-lauryl sarcosinate.
Suitable preferred additional anionic cleansing surfactants are sodium lauryl ether sulphosuccinate(n)EO, (where n is from 1 to 3), lauryl ether carboxylic acid (n) EO (where n is from 10 to 20).
Mixtures of any of the foregoing anionic cleansing surfactants may also be suitable.
If added, the total amount of additional anionic cleansing surfactant in shampoo compositions may generally range from 0.5 to 45 wt %, preferably from 1.5 to 35 wt %, more preferably from 5 to 20 wt %, calculated by total weight anionic cleansing surfactant based on the total weight of the composition.
The composition can include co-surfactants, to help impart aesthetic, physical or cleansing properties to the composition.
An example of a co-surfactant is a nonionic surfactant, which can be included in an amount ranging from 0.5 to 8 wt %, preferably from 2 to 5 wt % based on the total weight of the composition.
For example, representative nonionic surfactants that can be included in compositions include condensation products of aliphatic (C8--C18) primary or secondary linear or branched chain alcohols or phenols with alkylene oxides, usually ethylene oxide and generally having from 6 to 30 ethylene oxide groups.
Other representative nonionic surfactants include mono- or di-alkyl alkanolamides. Examples include coco mono- or di-ethanolamide and coco mono-isopropanolamide.
Further nonionic surfactants which can be included in compositions are the alkyl polyglycosides (APGs). Typically, the APG is one which comprises an alkyl group connected (optionally via a bridging group) to a block of one or more glycosyl groups. Preferred APGs are defined by the following formula:
RO-(G)n
wherein R is a branched or straight chain alkyl group which may be saturated or unsaturated and G is a saccharide group.
R may represent a mean alkyl chain length of from about C5 to about C20. Preferably R represents a mean alkyl chain length of from about C8 to about C12. Most preferably the value of R lies between about 9.5 and about 10.5. G may be selected from C5 or C6 monosaccharide residues, and is preferably a glucoside. G may be selected from the group comprising glucose, xylose, lactose, fructose, mannose and derivatives thereof. Preferably G is glucose.
The degree of polymerisation, n, may have a value of from about 1 to about 10 or more; preferably, the value of n lies from about 1.1 to about 2; most preferably the value of n lies from about 1.3 to about 1.5.
Suitable alkyl polyglycosides include for example those materials identified as: Oramix NS10 ex Seppic; Plantaren 1200 and Plantaren 2000 ex Henkel.
Other sugar-derived nonionic surfactants which can be included in compositions include the C10-C18 N-alkyl (C1-C6) polyhydroxy fatty acid amides, such as the C12-C18 N-methyl glucamides, as described for example in WO 92/06154 and U.S. Pat. No. 5,194,639, and the N-alkoxy polyhydroxy fatty acid amides, such as C10-C18 N-(3-methoxypropyl) glucamide.
A preferred example of a co-surfactant is an amphoteric or zwitterionic surfactant, which can be included in an amount ranging from 0.1 to about 10 wt %, preferably from 0.5 to 8, more preferably from 1 to 5 wt %, based on the total weight of the composition.
Examples of amphoteric or zwitterionic surfactants include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulphobetaines (sultaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphoacetates, alkyl amphopropionates, alkylamphoglycinates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, wherein the alkyl and acyl groups have from 8 to 19 carbon atoms. Typical amphoteric and zwitterionic surfactants for use in shampoos include lauryl amine oxide, cocodimethyl sulphopropyl betaine, lauryl betaine, cocamidopropyl betaine and sodium cocoamphoacetate.
A particularly preferred amphoteric or zwitterionic surfactant is cocamidopropyl betaine.
Mixtures of any of the foregoing amphoteric or zwitterionic surfactants may also be suitable. Preferred mixtures are those of cocamidopropyl betaine with further amphoteric or zwitterionic surfactants as described above. A preferred further amphoteric or zwitterionic surfactant is sodium cocoamphoacetate.
The total amount of surfactant (including any co-surfactant, and/or any emulsifier) in a composition is generally from 1 to 50 wt %, preferably from 2 to 40 wt %, more preferably from 10 to 25 wt % total surfactant based on the total weight of the composition.
Further Optional Ingredients
The compositions may contain one or more other ingredients. Such ingredients include further preservatives (e.g. bactericides), pH buffering agents, perfume carriers, polyelectrolytes, anti-wrinkle agents, anti-oxidants, sunscreens, anti-corrosion agents, pearlisers and/or opacifiers, natural oils/extracts, processing aids, e.g. electrolytes, hygiene agents, e.g. anti-bacterials and antifungals, thickeners, skin benefit agents, colorants, whiteners, gel-control agents, freeze-thaw stabilisers, bactericides, preservatives (for example 1,2-benzisothiazolin-3-one), hydrotropes, perfumes and mixtures thereof.
The compositions may also contain pH modifiers such as hydrochloric acid or lactic acid.
Although it is particularly suitable to employ anhydrous compositions herein, which is to say compositions that do not contain a discernible aqueous phase, any water present being associated with some other ingredient. The antiperspirant or deodorant compositions can additionally comprise an aqueous phase, and commonly together with an oil phase, the composition is in the form of an emulsion. In such compositions, the aqueous phase commonly constitutes from 10 wt % and particularly from 30 wt % of the total composition, often up to 97 wt %. The balance of the composition comprises the oil phase, including any suspended material and the emulsifier or emulsifiers. Emulsions particularly suitably comprise shear-sensitive encapsulated fragrance.
The composition preferably contains an antiperspirant active. Antiperspirant actives are preferably incorporated in an amount of from 0.5 to 50 wt %, particularly from 5 to 30 wt % and especially from 10% to 26 wt % of the composition. It is often considered that the main benefit from incorporating of up to 5 wt % of an antiperspirant active in a stick composition is manifest in reducing body odour, and that as the proportion of antiperspirant active increases, so the efficacy of that composition at controlling perspiration increases.
Antiperspirant actives for use herein are often selected from astringent active salts, including in particular aluminium, zirconium and mixed aluminium/zirconium salts, including both inorganic salts, salts with organic anions and complexes. Preferred astringent salts include aluminium, zirconium and aluminium/zirconium halides and halohydrate salts, such as chlorohydrates.
Aluminium halohydrates are usually defined by the general formula:
Al2(OH)xQy-wH2O in which Q represents chlorine, bromine or iodine, x is variable from 2 to 5 and x+y=6 while wH2O represents a variable amount of hydration. Especially effective aluminium halohydrate salts, known as activated aluminium chlorohydrates, are described in EP-A-6739 (Unilever NV et al).
Zirconium actives can usually be represented by the empirical general formula: ZrO(OH)2n-nzBz.wH2in which z is a variable in the range of from 0.9 to 2.0 so that the value 2n-nz is zero or positive, n is the valency of B, and B is selected from the group consisting of chloride, other halide, sulphamate, sulphate and mixtures thereof. Possible hydration to a variable extent is represented by wH2O. Preferable is that B represents chloride and the variable z lies in the range from 1.5 to 1.87. In practice, such zirconium salts are usually not employed by themselves, but as a component of a combined aluminium and zirconium-based antiperspirant.
Antiperspirant complexes based on the above-mentioned astringent aluminium and/or zirconium salts can be employed. The complex often employs a compound with a carboxylate group, and advantageously this is an amino acid. Examples of suitable amino acids include dl-tryptophan, dl-β-phenylalanine, dl-valine, dl-methionine and β-alanine, and preferably glycine. It is highly desirable to employ complexes of a combination of aluminium halohydrates and zirconium chlorohydrates together with amino acids such as glycine, which are disclosed in U.S. Pat. No. 3,792,068 (Luedders et al).
The proportion of solid antiperspirant salt in a suspension (anhydrous) composition normally includes the weight of any water of hydration and any complexing agent that may also be present in the solid active.
Desirably at least 90 wt %, preferably at least 95 wt % and especially at least 99 wt % of the particles have a diameter in the range of from 0.1 μm up to 100 μm, and usually have an average particle diameter of at least 1 μm and especially below 20 μm. In some highly desirable contact compositions the particles have a weight average particle size of at least 2 μm and particularly below 10 μm, such as in the range of from 3 to 8 μm.
The compositions may be emulsions. In such compositions, the antiperspirant active is commonly dissolved in the aqueous phase, commonly at a concentration in that phase of between 10 and 55 wt %. In many suitable emulsions, the concentration of antiperspirant active is chosen in relation to the weight of oils (including any non-encapsulated fragrance oils), decreasing progressively from a ratio of about 3:1 to 5:1 when the proportion of oils is below 10 wt % to a ratio in the range of 3:2 to 2:3 when the oils content is at least 50 wt % of the total composition (excluding any propellant). The compositions may include one or more thickeners or gellants (sometimes called structuring or solidifying agents) to increase the viscosity of or solidify the liquid carrier in which the particulate materials are suspended as is appropriate for application from respectively soft solid (anhydrous cream) dispensers or stick dispensers.
Compositions may be stick compositions. Such compositions desirably have a hardness as measured in a conventional penetration test (Seta) of less than 30 mm, preferably less than 20 mm and particularly desirably less than 15 mm. Many have a penetration of from 7 to 13 or 7.5 to 10 or 12.5 mm. The conventional penetration test employed herein, utilises a lab plant penetrometer equipped with a Seta wax needle (weight 2.5 g) which has a cone angle at the point of the needle specified to be 9°10′+/−15′. A sample of the composition with a flat upper surface is used. The needle is lowered onto the surface of the composition and then a penetration hardness measurement is conducted by allowing the needle with its holder to drop under the combined weight of needle and holder of 50 g for a period of five seconds after which the depth of penetration is noted. Desirably the test is carried out at six points on each sample and the results are averaged. The gellants for forming stick compositions herein are usually selected from one or more of two classes: non-polymeric fibre-forming gellants and waxes, optionally supplemented by incorporation of a particulate silica and/or an oil-soluble polymeric thickener. Waxes, when employed, are often selected from hydrocarbons, linear fatty alcohols, silicone polymers, esters of fatty acids or mixtures containing such compounds along with a minority (less than 50 wt % and often less than 20 wt %) of other compounds.
Non-polymeric fibre-forming gellants, when employed, are typically dissolved in a water-immiscible blend of oils at elevated temperature and on cooling precipitate out to form a network of very thin strands that are typically no more than a few molecules wide. One particularly effective category of such thickeners comprises N-acyl aminoacid amides and in particular linear and branched N-acyl glutamic acid dialkylamides, such as in particular N-lauroyl glutamic acid di n-butylamide and N-ethylhexanoyl glutamic acid di n-butylamide and especially mixtures thereof. Such amido gellants can be employed in anhydrous compositions, if desired, with 12-hydroxysteahc acid.
A gellant is often employed in a stick or soft solid composition at a concentration of from 1.5 to 30 wt %, depending on the nature of the gellant or gellants, the constitution of the oil blend and the extent of hardness desired. The anhydrous compositions can contain one or more optional ingredients, such as one or more of those selected from those identified below.
Optional ingredients include wash-off agents, often present in an amount of up to 10 wt % to assist in the removal of the formulation from skin or clothing. Such wash-off agents are typically nonionic surfactants such as esters or ethers containing a C5 to C22 alkyl moiety and a hydrophilic moiety which can comprise a polyoxyalkylene group (POE or POP) and/or a polyol.
The compositions herein can incorporate one or more cosmetic adjuncts. Such adjuncts can include skin feel improvers, such as talc or finely divided (i.e. high molecular weight) polyethylene, i.e. not a wax, for example Accumist™, in an amount of 1 up to about 10 wt %; a moisturiser, such as glycerol or polyethylene glycol (mol wt 200 to 600), for example in an amount of up to about 5 wt %; skin benefit agents such as allantoin or lipids, for example in an amount of up to 5 wt %; colours; skin cooling agents other than the already mentioned alcohols, such a menthol and menthol derivatives, often in an amount of up to 2 wt %. A further optional ingredient comprises a preservative, such as ethyl or methyl parabens or BHT (butyl hydroxy toluene) such as in an amount of from 0.01 to 0.1 wt %.
The compositions and particularly compositions intended to be delivered from a roll-on dispenser or a pump spray, conveniently comprise emulsions. In such emulsions the total oil content is often less than 10 wt %, for example comprising between 0.5 and 2 wt % of fragrance oils (non-encapsulated) and from 1 to 6 wt % of other oils, selected for example from the carrier oils described hereinbefore. It is particularly suitable to employ from 1 to 5 wt % of a triglyceride oil, such as sunflower seed oil.
Emulsions commonly employ a non-ionic surfactant acting as an emulsifier or mixture of emulsifiers providing an HLB value in the region of 6 to 10. An especially desirable range of emulsifiers comprises a hydrophilic moiety provided by a polyalkylene oxide (polyglycol), particularly polyethylene oxide, such as containing 4 to 6 EO units or a mixture of 2 to 4 plus 10 to 30 EO units and a hydrophobic moiety provided by an aliphatic hydrocarbon, preferably containing at least 10 carbons and commonly linear. The hydrophobic and hydrophilic moieties can be linked via an ester or ether linkage, possibly via an intermediate polyol such as glycerol.
Preferably the hydrophobic aliphatic substituent contains at least 12 carbons, and is derivable from lauryl, palmityl, cetyl, stearyl, Oleeryl and behenyl alcohol, and especially cetyl, stearyl or a mixture of cetyl and stearyl alcohols or from the corresponding carboxylic acids. Particularly conveniently, the combination of emulsifiers comprises steareth-2 and a selection from steareth-15 to steareth-30. The compositions desirably are substantially or totally free from water-soluble short chain monohydric alcohols (commonly recognised as up to Cs) and especially ethanol. Substantially in this context indicates a proportion of less than 5 wt % and preferably less than 1 wt % of the respective full or base composition.
Compositions may be aerosol compositions. Such compositions herein comprise a base composition, namely a full composition except for a propellant mixed with a propellant. The base composition commonly comprises the antiperspirant and/or deodorant active, the liquid carrier and often a suspending aid. Many suitable aerosol compositions are anhydrous. Such compositions typically have a proportion of carrier oils that is commonly from 50 to 95 wt % of the base composition, and the mixture commonly includes one or more volatile oils such as a volatile silicone oil and one or more non-volatile oils, often in a weight ratio of from 10:1 to 1:2 and particularly from 5:1 to 1:1. The concentration antiperspirant active in the base composition is often from 5% to 60 wt % and especially 10% to 45 wt %.
During the manufacture of compositions, it is especially desirable for the fragrance capsules to be incorporated into the composition with mixing at a rate and power input that does not damage the capsules. One convenient process sequence for preparing a stick or soft composition comprises first forming a solution of the structurant combination in the water-immiscible liquid or one of the water-immiscible liquids. This is normally carried out by agitating the mixture at a temperature sufficiently high that all the structurants dissolve (the dissolution temperature) such as a temperature in a range from 70 to 140° C. Any oil-soluble cosmetic adjunct can be introduced into oil phase, either before or after the introduction of the gellants. However, the fragrance oil, be it encapsulated or free, is commonly the last ingredient to be incorporated into the composition, after the antiperspirant active on account of its sensitivity often to elevated temperature. Commonly the resultant structurant solution is allowed to cool to a temperature that is intermediate between that at which the gellants dissolved and the temperature at which it would set, often reaching a temperature in the region of 60 to 90° C.
In some routes, the carrier oils can be mixed together prior to introduction of the gellants and the antiperspirant or deodorant active. In other preparative routes, it is desirable to dissolve all or a fraction of the gellants and especially for amido gellants in a first fraction of the composition, such as a branched aliphatic alcohol, e.g. isostearyl alcohol or octyldodecanol, optionally in conjunction with an alcohol having some water-miscibility and boiling point above the dissolution temperature of the amido gellant in the alcoholic fluid. This enables the remainder of the carrier fluids to avoid being heated to the temperature at which the structurants dissolve or melt. Such a process commonly involves mixing the fractions intensively in for example a “Sonolator”™. The fragrance capsules are most desirably introduced after any intensive mixing step. The proportion of the carrier fluids for dissolving the structurants is often from 25 to 50 wt % of the carrier fluids. In other preparative routes the particulate material is introduced into preferably a second fraction of the carrier oils, for example silicone and/or ester and/or hydrocarbon oils and thereafter, and thereafter the first fraction containing dissolved structurant and second fraction containing suspended particulate material are mixed at a temperature above that at which the composition gels, and often from 5° C. to 30° C. above the regular setting temperature of the composition, dispensing containers are filled and cooled or allowed to cool to ambient temperature.
The particles may be advantageously incorporated into surfactant-containing and, in particular laundry and personal care compositions. The particles are typically included in said compositions at levels of from 0.001 wt % to 10 wt %, preferably from 0.005 wt % to 7.55 wt %, most preferably from 0.01 wt % to 5 wt % of the total composition.
For laundry applications, one active ingredient in the compositions is preferably a surface active agent or a fabric conditioning agent. More than one active ingredient may be included. For some applications a mixture of active ingredients may be used.
Formulated compositions comprising the particles may contain a surface-active compound (surfactant) which may be chosen from soap and non-soap anionic, cationic, non-ionic, amphoteric and zwitterionic surface active compounds and mixtures thereof. Many suitable surface active compounds are available and are fully described in the literature, for example, in “Surface-Active Agents and Detergents”, Volumes I and II, by Schwartz, Perry and Berch. The preferred surface-active compounds that can be used are soaps and synthetic non soap anionic, and non-ionic compounds.
The compositions may contain linear alkylbenzene sulphonate, particularly linear alkylbenzene sulphonates having an alkyl chain length of from C8 to C15. It is preferred if the level of linear alkylbenzene sulphonate is from 0 wt % to 30 wt %, more preferably from 1 wt % to 25 wt %, most preferably from 2 wt % to 15 wt %, of the total composition.
Compositions may contain other anionic surfactants in amounts additional to the percentages quoted above. Suitable anionic surfactants are well-known to those skilled in the art. Examples include primary and secondary alkyl sulphates, particularly C8 to C15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.
Compositions may also contain non-ionic surfactant. Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C8 to C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C10 to C15 primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide).
It is preferred if the level of non-ionic surfactant is from 0 wt % to 30 wt %, preferably from 1 wt % to 25 wt %, most preferably from 2 wt % to 15 wt %, of a fully formulated composition comprising the particles.
Any conventional fabric conditioning agent may be used. The conditioning agents may be cationic or non-ionic. If the fabric conditioning compound is to be employed in a main wash detergent composition the compound will typically be non-ionic. For use in the rinse phase, typically they will be cationic. They may for example be used in amounts from 0.5 wt % to 35 wt %, preferably from 1 wt % to 30 wt % more preferably from 3 wt % to 25 wt % of a fully formulated composition comprising the particles.
Suitable cationic fabric softening compounds are substantially water-insoluble quaternary ammonium materials comprising a single alkyl or alkenyl long chain having an average chain length greater than or equal to C20 or, more preferably, compounds comprising a polar head group and two alkyl or alkenyl chains having an average chain length greater than or equal to C14. Preferably the fabric softening compounds have two long chain alkyl or alkenyl chains each having an average chain length greater than or equal to C16.
Most preferably at least 50 wt % of the long chain alkyl or alkenyl groups have a chain length of C18 or above. It is preferred if the long chain alkyl or alkenyl groups of the fabric softening compound are predominantly linear.
Quaternary ammonium compounds having two long-chain aliphatic groups, for example, distearyldimethyl ammonium chloride and di(hardened tallow alkyl) dimethyl ammonium chloride, are widely used in commercially available rinse conditioner compositions. Other examples of these cationic compounds are to be found in “Surfactants Science Series” volume 34 ed. Richmond 1990, volume 37 ed. Rubingh 1991 and volume 53 eds. Cross and Singer 1994, Marcel Dekker Inc. New York”.
The fabric softening compounds are preferably compounds that provide excellent softening, and are characterised by a chain melting Lβ to La transition temperature greater than 25° C., preferably greater than 35° C., most preferably greater than 45° C. This Lβ to La transition can be measured by differential scanning calorimetry as defined in “Handbook of Lipid Bilayers”, D Marsh, CRC Press, Boca Raton, Fla., 1990 (pages 137 and 337).
Substantially water-insoluble fabric softening compounds are defined as fabric softening compounds having a solubility of less than 1×10−3 wt % in demineralised water at 20° C. Preferably the fabric softening compounds have a solubility of less than 1×10−4 wt %, more preferably from less than 1×10−3 to 1×10−6 wt %.
Especially preferred are cationic fabric softening compounds that are water-insoluble quaternary ammonium materials having two C12-22 alkyl or alkenyl groups connected to the molecule via at least one ester link, preferably two ester links. Di(tallowoxyloxyethyl) dimethyl ammonium chloride and/or its hardened tallow analogue is an especially preferred compound of this class.
A second preferred type comprises those derived from triethanolamine (hereinafter referred to as TEA quats') as described in for example U.S. Pat. No. 3,915,867. Suitable materials are, for example, N-methyl-N,N,N-triethanolamine ditallowester or di-hardened-tallowester quaternary ammonium chloride or methosulphate. Examples of commercially available TEA quats include Rewoquat WE18 and Rewoquat WE20, both partially unsaturated (ex. WITCO), Tetranyl AOT-1, fully saturated (ex. KAO) and Stepantex VP 85, fully saturated (ex. Stepan).
It is advantageous if the quaternary ammonium material is biologically biodegradable.
It is also possible to include certain mono-alkyl cationic surfactants which can be used in main-wash compositions for fabrics. Cationic surfactants that may be used include quaternary ammonium salts of the general formula R1R2R3R4N+X− wherein the R groups are long or short hydrocarbon chains, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a counter-ion (for example, compounds in which R1 is a C8-C22 alkyl group, preferably a C8-C10 or C12-C14 alkyl group, R2 is a methyl group, and R3 and R4, which may be the same or different, are methyl or hydroxyethyl groups); and cationic esters (for example, choline esters).
The choice of surface-active compound (surfactant), and the amount present, will depend on the intended use of the detergent composition. In fabric washing compositions, different surfactant systems may be chosen, as is well known to the skilled formulator, for hand-washing products and for products intended for use in different types of washing machine.
The total amount of surfactant present will also depend on the intended end use and may, in fully formulated products, be as high as 60 wt %, for example, in a composition for washing fabrics by hand. In compositions for machine washing of fabrics, an amount of from 5 to 40 wt % is generally appropriate. Typically compositions will comprise at least 2 wt % surfactant e.g. 2 to 60 wt %, preferably 15 to 40 wt % most preferably 25 to 35 wt %.
Detergent compositions suitable for use in most automatic fabric washing machines generally contain anionic non-soap surfactant, or non-ionic surfactant, or combinations of the two in any suitable ratio, optionally together with soap.
Compositions, when used as main wash fabric washing compositions, will generally also contain one or more detergency builders. The total amount of detergency builder in compositions will typically range from 5 to 80 wt %, preferably from 10 to 60 wt % of composition.
Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB 1 437 950 (Unilever); crystalline and amorphous aluminosilicates, for example, zeolites as disclosed in GB 1 473 201 (Henkel), amorphous aluminosilicates as disclosed in GB 1 473 202 (Henkel) and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250 (Procter & Gamble); and layered silicates as disclosed in EP 164 514B (Hoechst). Inorganic phosphate builders, for example, sodium orthophosphate, pyrophosphate and tripolyphosphate are also suitable.
The compositions preferably contain an alkali metal, preferably sodium, aluminosilicate builder. Sodium aluminosilicates may generally be incorporated in end product formulations amounts of from 10 to 70 wt % (anhydrous basis), preferably from 25 to 50 wt %.
The alkali metal aluminosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8 1.5 Na2O. Al2O3. 0.8 6 SiO2.
These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5 3.5 SiO2 units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. Suitable crystalline sodium aluminosilicate ion exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble). The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof.
The zeolite may be the commercially available zeolite 4A widely used in laundry detergent powders. However, according to a preferred embodiment the zeolite builder incorporated in the compositions is maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070A (Unilever). Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium weight ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, and more preferably within the range of from 0.90 to 1.20.
Especially preferred is zeolite MAP having a silicon to aluminium weight ratio not exceeding 1.07, more preferably about 1.00. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material.
Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono , di- and trisuccinates, carboxymethyloxy succinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl and alkenylmalonates and succinates; and sulphonated fatty acid salts. This list is not intended to be exhaustive.
Especially preferred organic builders are citrates, suitably used in fully formulated compositions in amounts of from 5 to 30 wt %, preferably from 10 to 25 wt %; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt %, preferably from 1 to 10 wt %.
Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form.
Compositions comprising the particles according to the invention may also suitably contain a bleach system. Fabric washing compositions may desirably contain peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, capable of yielding hydrogen peroxide in aqueous solution.
Suitable peroxy bleach compounds include organic peroxides such as urea peroxide, and inorganic persalts such as the alkali metal perborates, percarbonates, perphosphates, persilicates and persulphates. Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate.
Especially preferred is sodium percarbonate having a protective coating against destabilisation by moisture. Sodium percarbonate having a protective coating comprising sodium metaborate and sodium silicate is disclosed in GB 2 123 044B (Kao).
The peroxy bleach compound is suitably present in a fully formulated product in an amount of from 0.1 to 35 wt %, preferably from 0.5 to 25 wt %. The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 0.1 to 8 wt %, preferably from 0.5 to 5 wt %.
Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and pernoanoic acid precursors. Especially preferred bleach precursors suitable for use in the compositions are N,N,N′,N′, tetracetyl ethylenediamine (TAED) and sodium nonanoyloxybenzene sulphonate (SNOBS). The novel quaternary ammonium and phosphonium bleach precursors disclosed in U.S. Pat. No. 4,751,015 and U.S. Pat. No. 4,818,426 (Lever Brothers Company) and EP 402 971A (Unilever), and the cationic bleach precursors disclosed in EP 284 292A and EP 303 520A (Kao) are also of interest.
The bleach system can be either supplemented with or replaced by a peroxyacid. Examples of such peracids can be found in U.S. Pat. No. 4,686,063 and U.S. Pat. No. 5,397,501 (Unilever). A preferred example is the imido peroxycarboxylic class of peracids described in EPA 325 288, EPA 349 940, DE 382 3172 and EP 325 289. A particularly preferred example is phthalimido peroxy caproic acid (PAP). Such peracids are suitably present at 0.1 to 12 wt %, preferably 0.5 to 10 wt %.
A bleach stabiliser (transition metal sequestrant) may also be present in fully formulated products. Suitable bleach stabilisers include ethylenediamine tetra-acetate (EDTA), the polyphosphonates such as Dequest (Trade Mark) and non-phosphate stabilisers such as EDDS (ethylene diamine disuccinic acid). These bleach stabilisers are also useful for stain removal especially in end-products containing low levels of bleaching species or no bleaching species.
An especially preferred bleach system comprises a peroxy bleach compound (preferably sodium percarbonate optionally together with a bleach activator), and a transition metal bleach catalyst as described and claimed in EP 458 397A, EP 458 398A and EP 509 787A (Unilever).
Advantageously in the compositions benefit agents, particularly, perfume components may be employed which are sensitive to bleaches as the encapsulation of, for example, the perfume component within the particles will provide some degree of protection to the perfume component or other benefit agent.
The fully formulated compositions may also contain one or more enzyme(s).
Suitable enzymes include the proteases, amylases, cellulases, oxidases, peroxidases and lipases usable for incorporation in detergent compositions. Preferred proteolytic enzymes (proteases) are, catalytically active protein materials which degrade or alter protein types of stains when present as in fabric stains in a hydrolysis reaction. They may be of any suitable origin, such as vegetable, animal, bacterial or yeast origin.
Proteolytic enzymes or proteases of various qualities and origins and having activity in various pH ranges of from 4 to 12 are available and can be used in the compositions. Examples of suitable proteolytic enzymes are the subtilisins which are obtained from particular strains of B. Subtilis B. licheniformis, such as the commercially available subtilisins Maxatase (Trade Mark), as supplied by Genencor International N.V., Delft, Holland, and Alcalase (Trade Mark), as supplied by Novozymes Industri NS, Copenhagen, Denmark.
Particularly suitable is a protease obtained from a strain of Bacillus having maximum activity throughout the pH range of 8 to 12, being commercially available, e.g. from Novozymes Industries NS under the registered trade names Esperase (Trade Mark) and Savinase (Trade Mark). The preparation of these and analogous enzymes is described in GB 1 243 785. Other commercial proteases are Kazusase (Trade Mark obtainable from Showa Denko of Japan), Optimase (Trade Mark from Miles Kali Chemie, Hannover, West Germany), and Superase (Trade Mark obtainable from Pfizer of U.S.A.).
Detergency enzymes are commonly employed in fully formulated products in granular form in amounts of from about 0.1 to about 3.0 wt % on product. However, any suitable physical form of enzyme may be used. Advantageously in the compositions benefit agents, for example, perfume components, may be employed which are sensitive to enzymes as the encapsulation of the perfume component (or other benefit agent) within the particles will provide some degree of protection to the perfume component (or other benefit agent).
The compositions may contain alkali metal, preferably sodium carbonate, in order to increase detergency and ease processing. Sodium carbonate may suitably be present in fully formulated products in amounts ranging from 1 to 60 wt %, preferably from 2 to 40 wt %. However, compositions containing little or no sodium carbonate are also within the scope of the invention.
The fully formulated detergent composition when diluted in the wash liquor (during a typical wash cycle) will typically give a pH of the wash liquor from 7 to 10.5 for a main wash detergent.
Particulate detergent compositions are suitably prepared by spray drying a slurry of compatible heat insensitive ingredients, and then spraying on or post-dosing those ingredients unsuitable for processing via the slurry. The skilled detergent formulator will have no difficulty in deciding which ingredients should be included in the slurry and which should not. It is particularly useful to add the perfume particles via post-dosing.
Particulate detergent compositions preferably have a bulk density of at least 400 g/litre, more preferably at least 500 g/litre. Especially preferred compositions have bulk densities of at least 650 g/litre, more preferably at least 700 g/litre.
Such powders may be prepared either by post tower densification of spray dried powder, or by wholly non tower methods such as dry mixing and granulation; in both cases a high-speed mixer/granulator may advantageously be used. Processes using high speed mixer/granulators are disclosed, for example, in EP 340 013A, EP 367 339A, EP 390 251A and EP 420 317A (Unilever).
Liquid detergent compositions can be prepared by admixing the essential and optional ingredients thereof in any desired order to provide compositions containing components in the requisite concentrations. Liquid compositions according to the present invention can also be in compact form which means it will contain a lower level of water compared to a conventional liquid detergent.
In order that the present invention may be still further understood and carried forth into practice it will be further described with reference to the following examples:
EXAMPLESIn the following examples, all weights are by weight of the total composition unless otherwise indicated.
Example 1 Preparation of Particles P1-P5, in Accordance with the Invention, and Comparative Particle PAA series of six composite acrylate core-urethane shell latex particles were prepared such that the proportion (i.e. thickness) of the poly(urethane) shell component increased concomitant with a reduction in the proportion of the poly(acrylate) core. The proportion of the particle mass composed of the poly(urethane) varied from approximately 50 to 100%. The particles were designated P1 to P5 and PA.
The particles were prepared by the following method.
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- 1. Poly(phenyl isocyanate), isophorone diisocyanate, butyl methacrylate or benzyl methacrylate, white mineral oil (Sonneborn Blandol) and N,N′-dimethylethanolamine were combined in a vial.
- 2. SLES-1EO (Texapon N701), Brij 58, 1,1,1-tris(hydroxymethyl)propane, and 1,6-hexane diol were dissolved in water and cooled to below 10° C. in an ice bath.
- 3. The two phases were mixed and shaken vigorously by hand, then emulsified using a sonic probe for 2×90 seconds at 60% power whilst cooled in an ice bath.
- 4. The emulsion was placed in a round bottom flask and stirred at an external temperature of 55° C. and 300 rpm.
- 5. 25 minutes after adding to the flask, Pluronic P65 solution was added over 5 minutes and the mixture stirred for 2 hours.
- 6. The temperature was increased to 80° C.
- 7. Ascorbic acid solution (0.43 g ascorbic acid in 2.2 ml water) was added
- 8. 0.25 g tertiary-butyl-hydroperoxide was dissolved in 5 ml water and the mixture was added via peristaltic pump to the reaction mixture over 45 to 60 minutes.
- 9. The mixture was heated for a further 2 hours before cooling.
The compositions of particles P1 to P5 and PA, as aqueous dispersions, are given in Table 1.
Note that the polyurethane (with higher Tg) forms the shell because it is made by interfacial polymerisation at the boundary of the emulsion phases. The polyacrylate polymer with the lower Tg forms the core.
Release of Perfume
The affinity of the odiferous fragrance or malodour components for sorption into polymers can be predicted using “solubility parameters”, as described in D. W. van Krevelen, “Properties of polymers”, 3rd edition, Elsevier Science Publishers, Amsterdam, Oxford, New York, 1990.The solubility parameter components for a wide range of substances can also be computed using software by Polymer Design Tools™ v1.5 (from DTW Associates Inc. Newtown, Pa., USA) and for small discrete fragrance molecules by Norgwyn Montgomery Software (distributed by ChemSW of Fairfield, Calif. in their Molecular Modelling Pro™ product). Calculations carried out by this method for common fragrance components predict a much higher compatibility for acrylate polymers as compared to urethanes.
Thus, particles comprising acrylate, in addition to polyurethane, (P1-P5) in a perfume containing formulation will adsorb perfume from the formulation and release perfume after application, whereas particles comprising polyurethane alone (comparative PA) will not adsorb fragrance from the formulation and are therefore unable to enhance its delivery after application.
This combination of the ability to retain malodour compounds, whilst releasing perfume compounds, is a surprising and desirable property of the particles of the invention.
Example 2 Absorption of Malodour Compounds by Particles P1 to P5 and PAThe absorption of the malodour compound isovaleric acid (commonly found in underarm sweat) by Particles P1 to P5, and comparative particle PA was measured by the following methodology:
0.5 ml volume mixtures containing 0.196 g/litre of isovaleric acid and 20 g/litre solids of Particles P1 to P5 and PA were prepared in high purity distilled water and sealed in Solid Phase Microextraction (SPME) headspace gas chromatography vials.
Two replicate samples were prepared for each particle. Particle-free control samples (two replicates) were prepared in the same manner but substituting distilled water for the particle suspensions. The pH values of the samples were measured using a calibrated pH meter and determined to be 4.01 +/−0.02. The compositions of the samples are listed in Table 2.
The samples were allowed to equilibriate at ambient temperature for 16 hours before analysis. The samples were then randomized and headspace air above the samples was sampled using SPME GC-MS.
Table 3 lists the measured peak areas together with the calculated ratio of the mean peak area for the Particle-containing sample relative to the Particle-free control.
It is evident that the level of isovaleric acid present in the headspace is significantly reduced compared to that in the particle-free control samples. Surprisingly, the more polyurethane rich Particles (P3-P5) favour depletion of isovaleric acid to a greater extent than Particles P1 and P2 without further incremental improvement as the level of polyurethane continues to increase.
Claims
1. A particle for the absorption of odiferous compounds, wherein the particle comprises:
- (a) a solid core comprising a first hydrophobic polymer, and
- (b) a shell comprising a second hydrophobic polymer
- wherein the Tg of the first hydrophobic polymer is lower than the Tg of the second hydrophobic polymer; wherein the particles have a mean particle size of less than 1 micron, preferably from 0.1 to 0.3 microns, wherein the odiferous compound is a malodour compound and wherein the ratio of (a):(b) is greater than 2:1.
2. A particle as claimed in claim 1, wherein the ratio of (a):(b) is from 2:1 to 10:1, preferably from 2:1 to 9:1.
3. A particle as claimed in claim 1, wherein the core comprises a polyacrylate polymer.
4. A particle as claimed in claim 3, wherein the polyacrylate polymer is selected from the group consisting of polybutyl methacrylate, polybenzyl methacrylate, poly lauryl methacrylate, poly-2-hydroxyethyl methacrylate, poly-2-hydroxypropyl methacrylates and mixtures thereof.
5. A particle as claimed in claim 1 wherein the shell comprises a polymer selected from a polyurea and a polyurethane, preferably polyurethane.
6. A particle as claimed in claim 5, wherein the shell comprises polyurethane formed from reaction of diisocyanate with diol and cross-linked with polyamine or polyol.
7. A particle as claimed in claim 1 wherein the core further comprises a benefit agent.
8. A particle as claimed in claim 1 wherein the benefit agent is selected from a fragrance, a skin care agent, an anti-oxidant, a vitamin, an anti-bacterial agent, an anti-inflammatory active, an anti-perspirant, a skin conditioning agent, a sunscreen and mixtures thereof.
9. A particle as claimed in claim 8, wherein the benefit agent is a fragrance.
10. A particle as claimed in claim 1 wherein the particle comprises a second shell.
11. A particle as claimed in claim 1 wherein the particle comprises a deposition aid.
12. A composition comprising a particle, as defined in claim 1 wherein the composition comprises an active ingredient.
13. A composition as claimed in claim 12, which is a home or personal care composition, selected from a deodorant, antiperspirant, shampoo, hair conditioner, skin care, skin cleansing product, a laundry detergent, laundry conditioner, a hard surface cleaner, floor cleaners and a soft surface refresher.
14. A composition as claimed in claim 12 wherein the active ingredient is selected from a surfactant, a cleaning agent, a solvent, a polymer, an antiperspirant active and mixtures thereof.
15. A composition as claimed in claim 14 which is a surfactant-containing laundry or personal care composition and wherein the particles are included at a level of from 0.001 wt % to 10 wt % of the total composition.
Type: Application
Filed: May 20, 2015
Publication Date: Jul 20, 2017
Applicant: Conopco, Inc., d/b/a UNILEVER (Englewood Cliffs, NJ)
Inventors: Martin Peter CROPPER (Birkenhead), Anthony HACKETT (Warrington), Craig Warren JONES (Claughton, Wirral), Adam John LIMER (Northwich), Katherine Mary THOMPSON (Wirral), Jeremy Nicholas WINTER (Chester)
Application Number: 15/313,072
