Method for producing a water soluble package

Abstract

A process for the preparation of a package containing a compacted particulate composition, comprising: a. placing a compacted particulate composition on a first film; b. positioning a second film over said composition; and c. sealing said first film to said second film and at least partly evacuating the atmosphere from the inside of said package so as to allow said first film and said second film to cling to said composition.

Description

The present invention relates to a process for the preparation of a water-soluble package containing a compacted particulate composition.

Tablets of a compressed particulate composition for use in dishwashing machines or laundry washing machines are well known. Such tablets are added to the machine at the start of its operation and are fully consumed by the end of the operation. Examples of such tablets are dishwashing tablets such as those sold under the trade mark Finish, water-softening tablets such as those sold under the trade mark Calgon, and laundry detergent tablets such as those sold under the trade mark Persil.

Such tablets are fairly fragile, and liable to break, fracture or chip, particularly when dropped onto the floor by a consumer, or when a package containing them falls from a high shelf when being stored in, for example, a warehouse or supermarket. It is possible to improve the strength of tablets by increasing the pressure at which they are compressed, but this can undesirably retard their dissolution when they are used.

There is almost always a complex interplay of factors in developing products of this type. There is often a compromise between the hardness of a tablet, and thus its durability, its friability, how easily it will chip or flake, and the dissolution time. In producing compacted particulate compositions the choice of ingredients can also be constrained; the use of too much organic material often leads to a slow solubilising product and large amounts of crystalline ingredients may need a binder added. In any event at least one disintegrating agent is usually needed, such as hydrated water-soluble salts (for example sodium acetate trihydrate), swelling agents (for example amorphous cellulose) or wicking agents (for example microcrystalline cellulose) to draw water into the solid. The use of disintegrating/binding agents, or any tabletting aid, adds to the cost of the tablet.

Most tablets are wrapped in a material prior to packaging, such as blister packs, or foil wrapped into individual sachets. Often the wrapping is needed for any one or more of the following reasons: (1) to act as a physical barrier, so as to protect the contents from moisture; (2) to physically protect the contents such that if they fracture, the broken tablet does not contaminate the primary packaging; (3) to act as a child resistant closure.

We have discovered a process for packaging compacted particulate compositions by which the resistance of the composition to physical damage is surprisingly increased. One of the main advantages is that a wider range of physical properties of the compacted particulate composition can be tolerated, such as reduced hardness and increased friability, thus allowing a wider window of ingredient selection and manufacturing tolerances.

WO 03031266 describes a process for making a two chamber product by which a first water soluble film is formed into a pocket. A composition is placed into the formed pocket and a second pocket for filling and sealing is formed by applying a vacuum through the bottom of the pocket formed by the first water-soluble film and through the composition held therein.

WO 02098394 describes a process for coating tablets involving applying a water-soluble film to an upper surface of the tablet, cutting off the excess, turning the tablet over and repeating the coating process to coat the other side of the tablet.

The present invention provides a process for the preparation of a package containing a compacted particulate composition, comprising:

• • a. placing a compacted particulate composition on a first film;
  • b. positioning a second film over said composition; and
  • c. sealing said first film to said second film and at least partly evacuating the atmosphere from the inside of said package so as to allow said first film and said second film to cling to said composition.

The process offers a simple one step method of intimately wrapping a compacted particular composition.

Although not bound by this theory, it is believed that the intimate contact of the film to the composition holds the composition in place, restricting its freedom to move. Surprisingly, however, the wrapped compositions do not easily fracture or chip. Thus the film does not function merely to hold fractured tablets together; instead it prevents fracturing from occurring so that the tablet retains its structural integrity. The benefits are further increased by the use of a films which have the ability to shrink back to their original form after being stretched, thus creating compressive forces within the packaging which are exerted onto the composition contained within.

Preferably the first film is of a first polymer and the second film is of a second polymer. The first and second films, and the first and second polymers, can be the same or different. The first polymer and/or the second polymer is desirably water-soluble, which term is taken to include water-dispersible. The package is also preferably water-soluble.

The process of the present invention covers or wraps a tablet of a compressed particulate composition in a film. The tablet may be a conventional tablet of the type which is already known. Tablets made by compressing a particulate composition have a surface which is rough, the surface roughness being determined by a number of factors including the sizes of the particles before they are compressed and the compression pressure. It is also postulated, although again the applicant is not bound by this theory, that the increased strength of the tablet arises from the interaction of the outer polymer film and the rough surface of the tablet and/or compression of the tablet by the outer film.

In step a. of the process of the present invention a compacted particulate composition is placed on a first film, preferably of a water-soluble polymer. The compacted particulate composition is formed by compressing a particulate composition. The particles may, if desired, be treated before they are compressed, for example by agglomeration and/or granulation. The composition before it is compressed may, for example, have a mean particle size of from 100 to 2000 μm, preferably 200 to 1200 μm.

The composition may be compressed at a compression pressure of, for example, from 50 to 1000 kg/cm², preferably from 60 to 300 kg/cm² for laundry tablets or from 400 to 1000 kg/cm², more preferably from 500 to 700 kg/cm², for dishwashing tablets.

The compacted composition has a degree of surface roughness since it is prepared from a particulate composition. Desirably the surface roughness R_a of at least one of the surfaces of the compacted composition, preferably at least two, three or four or more, preferably all the surfaces is at least 1 μm, more preferably at least 3 μm, even more preferably at least 10 μm. Desirably the surface roughness R_a of at least one of the surfaces of the compacted composition, preferably at least two, three or four or more, preferably all the surfaces, is less than 50 μm, more preferably less than 30 μm, and even more preferably less than 20 μm. A particularly preferred range is 10 to 20 μm, preferably for dishwashing or laundry tablets.

Desirably the surface roughness R_z of at least one of the surfaces of the compacted composition, preferably at least two, three or four or more, preferably all the surfaces, is at least 10 μm, more preferably at least 20 μm and even more preferably a least 35 μm. Desirably the surface roughness R_z of at least one of the surfaces of the compacted composition, preferably at least two, three or four or more, preferably all the surfaces is less than 200 μm, more preferably less than 100 μm and most preferably less than 70 μm. A particularly preferred range is 35 to 70 μm, particularly for dishwashing or laundry tablets.

The surface roughness R_a and R_z can easily be measured, for example using a TR 100 Surface Roughness Tester from Moore and Wright, Sheffield, U.K.

We have found that with a surface roughness, as defined above, the first and/or second film more evenly forms over the compacted composition. Whilst not wishing to be bound by theory we believe this is due to the ability of the air to be easily evacuated, even when the film is in contact with the compacted composition, due to the channels found in rough surface of the compacted composition.

The compacted composition may be of any shape or form. It is most desirably in the form of a tablet. It may, for example, be in the form of a cuboid, cylinder or prism. It may also comprise a single particulate composition or two, three or even more compositions. As long as at least one particulate composition is used, the remaining compositions need not necessarily provide a high degree of surface roughness. For example, the compacted particulate composition may comprise two, three or more layers. Preferably all two, three or more layers respectively may be formed from a particulate composition, but one or more layers may not necessarily have a surface roughness, particularly if they are internal layers or inserts.

Preferably at least 50% and up to 100% of the surface area of the composition being packaged has the appropriate surface roughness, more preferably at least 80%, and even more preferably at least 95%.

The packages may contain one or more than one compacted particulate composition. If the packages contain two or more compositions, they can have a particularly attractive appearance since the compositions, which may be identical or different, may be held in a fixed position in relation to each other. The compositions can be easily differentiated to accentuate their difference. For example, the compositions can have a different physical appearance, or can be coloured differently.

The packages may have any desired shape. The shape of the outside of the packages follows the shape of the packaged composition. For example the package can have a irregular or regular geometrical shape such as a cube, cuboid, pyramid, dodecahedron or cylinder. The cylinder may have any desired cross-section, such as a circular, triangular or square cross-section.

If the composition has two or more phases, the individual phases need not necessarily be regular or identical. For example, if the final composition has a cuboid shape, the individual phases may have different sizes to accommodate different quantities of compositions.

The compacted particulate composition may also, for example, comprise an insert, which may be held in a depression within the compact. The insert may also stand proud of the compact. For example, the compacted particulate composition may be in the form of a tablet, especially a cuboid tablet, comprising one, two or more layers, and an insert, for example in the form of a ball in a mould. An example of such a tablet is that sold under the trade mark Finish by Reckitt Benckiser plc.

The first and second films may be the same or different. Each film may, for example, be rigid or flexible.

Each film may, for example, comprise any polymer. Desirably, however, each film, and more preferably all the films, are water soluble (which term is taken to include water dispersible). Examples of non-water soluble films are poly(vinyl alcohol) (PVOH) and polyalkylenes such as polyethylene and polypropylene homopolymers and copolymers, for example modified polyethylenes such as PET or Surlyn (registered trade mark). Examples of water-soluble polymers are PVOH, cellulose derivatives such as hydroxypropyl methyl cellulose (HPMC), gelatin, poly(vinylpyrrolidone), poly(acrylic acid) or an ester thereof or poly(maleic acid) or an ester thereof. Copolymers of any of these polymers may also be used. Generally, better results can be obtained from polymers which have a large shrink-back property after they have been stretched. Accordingly each or all of the films may be stretched before they are used, for example by monoaxially or biaxially stretching or by stretching in or over a mould.

An example of a preferred PVOH is an esterified or etherified PVOH. The PVOH may be partially or fully alcoholised or hydrolysed. For example it may be from 40 to 100%, preferably from 70 to 92%, more preferably about 88% or about 92%, alcoholised or hydrolysed. The degree of hydrolysis is known to influence the temperature at which the PVOH starts to dissolve in water. 88% hydrolysis corresponds to a PVOH soluble in cold (ie room temperature) water, whereas 92% hydrolysis corresponds to a PVOH soluble in warm water.

By choosing an appropriate water-soluble polymer it is possible to ensure that it dissolves at a desired temperature. Thus each or both films may be cold water (20° C.) soluble, but may be insoluble in cold water and only become soluble in warm or hot water having a temperature of, for example, 30° C., 40° C., 50° C. or even 60° C.

Desirably each film consists essentially of, or consists of, the polymer composition. It is possible for suitable additives such as plasticisers, lubricants and colouring agents to be added. A particularly attractive appearance can be achieved by having the films in different colours, or by having one film uncoloured and the other coloured. Components which modify the properties of the polymer may also be added. Plasticisers are generally used in an amount of up to 20 wt %, for example from 10 to 20 wt %. Lubricants are generally used in an amount of 0.5 to 5 wt %. The polymer is therefore generally used in an amount of from 75 to 84.5 wt %, based on the total amount of the moulding composition. Suitable plasticisers are, for example, pentaerythritols such as depentaerythritol, sorbitol, mannitol, glycerine and glycols such as glycerol, ethylene glycol and polyethylene glycol. Solids such as talc, stearic acid, magnesium stearate, silicon dioxide, zinc stearate or colloidal silica may be used as lubricants.

It is also possible to include one or more particulate solids in the films in order to accelerate the rate of dissolution of the film. Dissolution of the solid in water is sufficient to cause an acceleration in the break-up of the film, particularly if a gas is generated.

Examples of such solids are alkali and alkaline earth metal, such as sodium, potassium, magnesium and calcium, bicarbonate and carbonate, in conjunction with an acid. Suitable acids are, for example acidic substances having carboxylic or sulfonic acid groups or salts thereof. Examples are cinnamic, tartaric, mandelic, fumaric, maleic, malic, palmoic, citric and naphthalene disulfonic acids, as free acids or as their salts, for example with alkali or alkaline earth metals.

Each or both films may be a single film, or a laminated film as disclosed in GB-A-2,244,258. The layers in a film laminate may be the same or different. Thus they may each comprise the same polymer or a different polymer.

Each film may be produced by any process, for example by extrusion and blowing or by casting. Each film may be unoriented, monoaxially oriented or biaxially oriented. If the layers in the film are oriented, they usually have the same orientation, although their planes of orientation may be different if desired.

The process of the present invention may be based on any process which can wrap the compacted particulate composition and in which the films can be made to cling to the composition. Thus, for example, it can be based on a thermoforming (which term includes vacuum forming), skin-wrapping or drape-forming process.

Skin wrapping and drape-forming processes are well known. An example of such processes is disclosed in WO 95/21105, herein incorporated by reference. In these processes the object to be wrapped is placed on a first surface of the first film, preferably of a water-soluble polymer, which acts as a backing material. The first film is preferably planar, i.e. flat, but may be of a different configuration. For example it may comprise one or more indentations into which the composition to be packaged is placed. Such indentations may be formed by, for example, a thermoforming process. The second film, preferably of a water-soluble polymer, is placed over the compacted particulate material and over the first surface of the backing material, and the first and second films are sealed together.

Ideally the platten on which the first film is supported is substantially flat, by substantially flat we mean the surface of the platten does not deviate at any point by more than ±5°. Alternatively the platten may be contoured to fit the slope of the tablet. However, this is not always necessary since evacuation contours the film to the compacted composition.

The second film, preferably of a water-soluble polymer, is generally heated to its Tg or above so that it softens before it is placed over the compacted particulate composition. In a skin wrapping process the second film is drawn down by applying a vacuum or reduced pressure under it. In a drape-forming process the second film is pushed down by application of pressure above it. The process of the present invention may be based on either of these methods, or a combination of both.

Thermoforming processes are also well known. An example of such a process is disclosed in WO 00/55045, herein incorporated by reference.

A suitable thermoforming process comprises:

a. producing a pocket surrounded by a sealing portion in the first film, preferably of a water-soluble polymer;

b. placing the compacted particulate composition in the pocket;

c. placing the second film, preferably of a water-soluble polymer, on top of the filled pocket and across the sealing portion of the first film; and

d. sealing the films together at the sealing portion.

In accordance with the present invention the inside of the package is at least partly evacuated such that the films cling to the packaged composition.

In a thermoforming process the first film is heated so that it softens before it is formed into a pocket. The film may be drawn down or blown down into a mould. Thus, for example, the film is heated to the thermoforming temperature using a thermoforming heater plate assembly, and then drawn down under vacuum or blown down under pressure into the mould. One skilled in the art can choose an appropriate temperature, pressure or vacuum and dwell time to achieve an appropriate pocket. The amount of vacuum or pressure and the thermoforming temperature used depend on the thickness and porosity of the film and on the polymer or mixture of polymers being used.

In all processes, in particular thermoforming, drape forming and skin-wrapping processes, a suitable temperature for the preferred films of PVOH or modified PVOH which is to be deformed, which is said first film in a thermoforming process and said second film is a skin-wrapping or drape-forming process, is, for example, from 90 to 130° C., especially 90 to 120° C. A suitable forming pressure is, for example, 69 to 138 kPa (10 to 20 p.s.i.), especially 83 to 117 kPa (12 to 17 p.s.i.). A suitable forming vacuum is 0 to 4 kPa (0 to 40 mbar), especially 0 to 2 kPa (0 to 20 mbar). A suitable dwell time is, for example, 0.4 to 2.5 seconds, especially 2 to 2.5 seconds.

While desirably conditions chosen within the above ranges, it is possible to use one or more of these parameters outside the above ranges, although it may be necessary to compensate by changing the values of the other two parameters.

After the composition has been placed in the first film, said second film is placed on top of the filled pocket and across the sealing portion, and the films are sealed together at the sealing portion.

In a thermoforming process the first film is stretched to form the pocket. In a skin wrapping process the second film is stretched over the compacted particulate composition. Desirably the film which is not stretched has a thickness which is less than that of the film which is stretched because localised thinning of the sheet will not occur.

In these processes the thickness of the film which is stretched is preferably 30 to 2000 μm, especially 35 to 150 μm and more especially 40 to 100 μm. These measurements are before stretching; after stretching some of the film will be thinner, particularly around corners.

The thickness of the film which is not stretched is generally from 20 to 160 μm, preferably from 40 to 100 μm, such as 40 to 80 μm or 50 to 60 μm.

The films are sealed together in a known manner. Sealing can simply occur under the forming conditions used in the process of the present invention, particularly when heat and pressure are used. However, it is also possible for additional sealing techniques to be used. For example, heat sealing or infra-red, radio frequency, ultrasonic, laser, solvent, adhesive, vibration, electromagnetic, hot gas, hot plate or insert bonding friction sealing or spin welding can be used. Heat sealing is preferred.

Heat sealing conditions depend on the machine and material used. Generally the sealing temperature is from 100 to 180° C. The pressure is usually from 100 to 500 kPa (1 to 5 bar). The dwell time is generally from 1.3 to 2.5 seconds.

It is an essential aspect of the present invention that the atmosphere, which of course is usually air, is at least partly evacuated from the inside of the package. Desirably a vacuum of 20 kPa (200 mbar) or less is applied during the evacuation process, more preferably 5 kPa (50 mbar) or less. Of course, once the films have clung to the packaged composition the pressure inside the packages may increase a little due to the smaller volume being enclosed.

The atmosphere may be at least partly evacuated from the inside of the package by any suitable means, but a particularly appropriate means is to remove the atmosphere through one or more holes in the first or second film. For example, the film may be porous or be perforated, for example having from 1 to 50 holes, preferably from 2 to 10 holes, most preferably from 3 to 5 holes, and especially 4 holes per square centimetre.

Removal of the atmosphere can take place during one of the steps when the package is formed. For example, in a thermoforming process the vacuum applied at the bottom, and optionally sides, of the mould also at least partly removes the atmosphere from the inside of the package after it has been sealed. In this embodiment, it may be necessary to allow the containers to rest in the thermoforming mould for a little while, for example of the order of a few seconds, to allow time for the atmosphere inside the container to be evacuated. In a skin wrapping process, the vacuum applied under the first film at least partly removes the atmosphere from the inside of the package.

It is also possible to remove the atmosphere from the inside of the packages by other means, for example by placing one or more of the packages having porous or perforated films in a vessel, and then extracting the atmosphere from the vessel. The atmosphere will be at least partly removed from the inside of packages which have at least one hole in the first or second film.

Another possibility is to evacuate at least partly the atmosphere from the inside of said package by sealing said first film to said second film under a vacuum. In this way, it can be ensured that the pressure inside the packages is less than atmospheric pressure, so the films cling to the packaged composition once the packages are subjected to normal atmospheric pressure. While, for this aspect of the invention, it is only necessary for the sealing to occur under vacuum (which term includes reduced pressure of less than 1 atmosphere), in practice it is convenient to carry out steps a., b. and c. in a vacuum chamber.

A further possible embodiment is to evacuate at least partly the atmosphere from the inside of said package via a conduit and removing said conduit while or after said films are sealed together.

We have surprisingly discovered that even though it is an essential aspect of the invention that the atmosphere is at least partly evacuated from inside the package, precautions do not have to be taken to ensure that air cannot re-enter the package. Thus, for example, any holes which are used to evacuate the atmosphere do not have to be sealed after the process is completed, although they may be subsequently sealed if it is desired. It is postulated, although again the applicant is not bound by this theory, that there is still interaction of the film and the rough surface of the tablet even though air is allowed to re-enter the package. This may be due to shrinkage of the polymer of the stretched film after it is cooled, particularly in the case of PVOH.

It is possible for one or more of the films, particularly the backing material in a skin wrapping process or the lidding film in a thermoforming process, to have incorporated therein a composition. Thus, for example, one or more of the films can themselves contain compositions formed in the films by a previous operation such as thermoforming or vertical form fill sealing.

DRAWINGS

The drawings show a drape coating process adapted to the present invention wherein in FIG. 1 a compacted composition 1 is placed onto a perforated cast PVOH film (perforations not shown 2. The film is supported on a flat metal platten 3 through which air holes 4 allow the evacuation of air through the plutten and film. A top coat PVOH film 5 is heated (heater platten not shown) and dropped over the compacted composition. A tight seal is made between the two films around the table in FIG. 1c and air is evacuated simultaneously through the platten and bottom film. The two films are stamp cut at points 7 so that the . . . compacted composition may be removed from the film web.

The composition within the package need not be uniform. For example, during manufacture the package could first be fed with a settable composition, for example, a gel, and then with the compacted particulate composition. One of these compositions could dissolve slowly in the washing process so as to deliver its charge over a long period within the washing process. This might be useful, for example, to provide an immediate, delayed or sustained delivery of a component such as a softening agent.

We have also surprisingly found that, when using a skin-wrapping process the top surface of the compacted composition furthest away from the backing film does not have to be flat or convex in order to ensure adequate removal of the atmosphere from inside the package when the top surface is concave or contains an insert. This is because the atmosphere can escape by diffusion through the granulated composition itself to the sides of the compact.

The composition(s) which can be held in the package, or in each phase in the composition held in the package, may independently be a fabric care, surface care or dishwashing composition. Thus, for example, they may be a dishwashing, water-softening, laundry or detergent composition, or a rinse aid. Such compositions may be suitable for use in a domestic washing machine. The compositions may also independently be a disinfectant, antibacterial or antiseptic composition, or a refill composition for a trigger-type spray. Such compositions are generally packaged in total amounts of from 5 to 100 g, especially from 15 to 40 g. For example, a laundry composition may weigh from 15 to 40 g, a dishwashing composition may weigh from 15 to 30 g and a water-softening composition may weigh from 15 to 40 g.

The phases may have the same or different size and/or shape. In general, if it is desired to have phases containing different quantities of components, the phases have volume ratios of from 2:1 to 20:1, especially from 4:1 to 10:1.

The package may also have a hook portion so that it can be hung, for example, from an appropriate place inside a dishwashing machine.

The packages produced by the process of the present invention may, if desired, have a maximum dimension of 5 cm, excluding any flanges. For example, a container may have a length of 1 to 5 cm, especially 3.5 to 4.5 cm, a width of 1.5 to 3.5 cm, especially 2 to 3 cm, and a height of 1 to 2 cm, especially 1.25 to 1.75 cm.

If more than one composition is present, the compositions may be appropriately chosen depending on the desired use of the article.

If the article is for use in laundry washing, the primary composition may comprise, for example, a detergent, and the secondary composition may comprise a bleach, stain remover, water-softener, enzyme or fabric conditioner. The article is adapted to release the compositions at different times during the laundry wash. For example, a bleach or fabric conditioner is generally released at the end of a wash, and a water-softener is generally released at the start of a wash. An enzyme may be released at the start or the end of a wash.

If the article is for use as a fabric conditioner, the primary composition may comprise a fabric conditioner and the secondary component may comprise an enzyme which is released before or after the fabric conditioner in a rinse cycle.

If the article is for use in dishwashing the primary composition may comprise a detergent and the secondary composition may comprise a water-softener, salt, enzyme, rinse aid, bleach or bleach activator. The article is adapted to release the compositions at different times during the laundry wash. For example, a rinse aid, bleach or bleach activator is generally released at the end of a wash, and a water-softener, salt or enzyme is generally released at the start of a wash.

Examples of surface care compositions are those used in the field of surface care, for example to clean, treat or polish a surface. Suitable surfaces are, for example, household surfaces such as worktops, as well as surfaces of sanitary ware, such as sinks, basins and lavatories.

The ingredients of each composition depend on the use of the composition. Thus, for example, the composition may contain surface active agents such as an anionic, □on-ionic, cationic, amphoteric or zwitterionic surface active agents or mixtures thereof.

Examples of anionic surfactants are straight-chained or branched alkyl sulfates and alkyl polyalkoxylated sulfates, also known as alkyl ether sulfates. Such surfactants may be produced by the sulfation of higher C₈-C₂₀ fatty alcohols.

Examples of primary alkyl sulfate surfactants are those of formula:
ROSO₃⁻M⁺
wherein R is a linear C₈-C₂₀ hydrocarbyl group and M is a water-solubilising cation. Preferably R is C₁₀-C₁₆ alkyl, for example C₁₂-C₁₄, and M is alkali metal such as lithium, sodium or potassium.

Examples of secondary alkyl sulfate surfactants are those which have the sulfate moiety on a “backbone” of the molecule, for example those of formula:
CH₂(CH₂)_n(CHOSO₃⁻M⁺)(CH₂)_mCH₃
wherein m and n are independently 2 or more, the sum of m+n typically being 6 to 20, for example 9 to 15, and M is a water-solubilising cation such as lithium, sodium or potassium.

Especially preferred secondary alkyl sulfates are the (2,3) alkyl sulfate surfactants of formulae:
CH₂(CH₂)_x(CHOSO₃⁻M+)CH₃ and
CH₃(CH₂)_x(CHOSO₃⁻M⁺)CH₂CH₃
for the 2-sulfate and 3-sulfate, respectively. In these formulae x is at least 4, for example 6 to 20, preferably 10 to 16. M is cation, such as an alkali metal, for example lithium, sodium or potassium.

Examples of alkoxylated alkyl sulfates are ethoxylated alkyl sulfates of the formula:
RO(C₂H₄O)_nSO₃⁻M⁺
wherein R is a C₈-C₂₀ alkyl group, preferably C₁₀-C₁₈ such as a C₁₂-C₁₆, n is at least 1, for example from 1 to 20, preferably 1 to 15, especially 1 to 6, and M is a salt-forming cation such as lithium, sodium, potassium, ammonium, alkylammonium or alkanolammonium. These compounds can provide especially desirable fabric cleaning performance benefits when used in combination with alkyl sulfates.

The alkyl sulfates and alkyl ether sulfates will generally be used in the form of mixtures comprising varying alkyl chain lengths and, if present, varying degrees of alkoxylation.

Other anionic surfactants which may be employed are salts of fatty acids, for example C₈-C₁₈ fatty acids, especially the sodium or potassium salts, and alkyl, for example C₈-C₁₈, benzene sulfonates.

Examples of non-ionic surfactants are fatty acid alkoxylates, such as fatty acid ethoxylates, especially those of formula:
R(C₂H₄O)_nOH
wherein R is a straight or branched C₈-C₁₆ alkyl group, preferably a C₉-C₁₅, for example C₁₀-C₁₄, alkyl group and n is at least 1, for example from 1 to 16, preferably 2 to 12, more preferably 3 to 10.

The alkoxylated fatty alcohol non-ionic surfactant will frequently have a hydrophilic-lipophilic balance (HLB) which ranges from 3 to 17, more preferably from 6 to 15, most preferably from 10 to 15.

Examples of fatty alcohol ethoxylates are those made from alcohols of 12 to 15 carbon atoms and which contain about 7 moles of ethylene oxide. Such materials are commercially marketed under the trademarks Neodol 25-7 and Neodol 23-6.5 by Shell Chemical Company. Other useful Neodols include Neodol 1-5, an ethoxylated fatty alcohol averaging 11 carbon atoms in its alkyl chain with about 5 moles of ethylene oxide; Neodol 23-9, an ethoxylated primary C₁₂-C₁₃ alcohol having about 9 moles of ethylene oxide; and Neodol 91-10, an ethoxylated C₉-C₁₁ primary alcohol having about 10 moles of ethylene oxide.

Alcohol ethoxylates of this type have also been marketed by Shell Chemical Company under the Dobanol trademark. Dobanol 91-5 is an ethoxylated C₉-C₁₁ fatty alcohol with an average of 5 moles ethylene oxide and Dobanol 25-7 is an ethoxylated C₁₂-C₁₅ fatty alcohol with an average of 7 moles of ethylene oxide per mole of fatty alcohol.

Other examples of suitable ethoxylated alcohol □on-ionic surfactants include Tergitol 15-S-7 and Tergitol 15-S-9, both of which are linear secondary alcohol ethoxylates available from Union Carbide Corporation. Tergitol 15-S-7 is a mixed ethoxylated product of a C₁₁-C₁₅ linear secondary alkanol with 7 moles of ethylene oxide and Tergitol 15-S-9 is the same but with 9 moles of ethylene oxide.

Other suitable alcohol ethoxylated non-ionic surfactants are Neodol 45-11, which is a similar ethylene oxide condensation products of a fatty alcohol having 14-15 carbon atoms and the number of ethylene oxide groups per mole being about 11. Such products are also available from Shell Chemical Company.

Further non-ionic surfactants are, for example, C₁₀-C₁₈ alkyl polyglycosides, such s C₁₂-C₁₆ alkyl polyglycosides, especially the polyglucosides. These are especially useful when high foaming compositions are desired. Further surfactants are polyhydroxy fatty acid amides, such as C₁₀-C₁₈ N-(3-methoxypropyl)glycamides and ethylene oxide-propylene oxide block polymers of the Pluronic type.

Examples of cationic surfactants are those of the quaternary ammonium type.

The total content of surfactants in the composition is desirably 60 to 95 wt %, especially 75 to 90 wt %. Desirably an anionic surfactant is present in an amount of 50 to 75 wt %, the nonionic surfactant is present in an amount of 5 to 50 wt %, and/or the cationic surfactant is present in an amount of from 0 to 20 wt %. The amounts are based on the total solids content of the composition, i.e. excluding any solvent which may be present.

The compositions, particularly when used as laundry washing or dishwashing compositions, may also independently comprise enzymes, such as protease, lipase, amylase, cellulase and peroxidase enzymes. Such enzymes are commercially available and sold, for example, under the registered trade marks Esperase, Alcalase and Savinase by Nova Industries A/S and Maxatase by International Biosynthetics, Inc. Desirably the enzymes are independently present in the compositions in an amount of from 0.5 to 3 wt %, especially 1 to 2 wt %, when added as commercial preparations they are not pure and this represents an equivalent amount of 0.005 to 0.5 wt % of pure enzyme.

Compositions used in dishwashing independently usually comprise a detergency builder. The builders counteract the effects of calcium, or other ion, water hardness. Examples of such materials are citrate, succinate, malonate, carboxymethyl succinate, carboxylate, polycarboxylate and polyacetyl carboxylate salts, for example with alkali metal or alkaline earth metal cations, or the corresponding free acids. Specific examples are sodium, potassium and lithium salts of oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, C₁₀-C₂₂ fatty acids and citric acid. Other examples are organic phosphonate type sequestering agents such as those sold by Monsanto under the trade mark Dequest and alkylhydroxy phosphonates. Citrate salts and C₁₂-C₁₈ fatty acid soaps are preferred. Further builders are; phosphates such as sodium, potassium or ammonium salts of mono-, di- or tri-poly or oligo-phosphates; zeolites; silicates, amorphous or structured, such as sodium, potassium or ammonium salts.

Other suitable builders are polymers and copolymers known to have builder properties. For example, such materials include appropriate polyacrylic acid, polymaleic acid, and polyacrylic/polymaleic and copolymers and their salts, such as those sold by BASF under the trade mark Sokalan.

The builder is desirably present in an amount of up to 90 wt %, preferably 15 to 90 wt %, more preferable 15 to 7.5 wt %, relative to the total weight of the composition. Further details of suitable components are given in, for example, EP-A-694,059, EP-A-518,720 and WO 99/06522.

The compositions can also optionally comprise one or more additional ingredients. These include conventional detergent composition components such as further surfactants, bleaches, bleach enhancing agents, builders, suds boosters or suds suppressors, anti-tarnish and anticorrosion agents, organic solvents, co-solvents, phase stabilisers, emulsifying agents, preservatives, soil suspending agents, soil release agents, germicides, pH adjusting agents or buffers, non-builder alkalinity sources, chelating agents, clays such as smectite clays, enzyme stabilizers, anti-limescale agents, colourants, dyes, hydrotropes, dye transfer inhibiting agents, brighteners, and perfumes. If used, such optional ingredients will generally constitute no more than 10 wt %, for example from 1 to 6 wt %, the total weight of the compositions.

Compositions which comprise an enzyme may optionally contain materials which maintain the stability of the enzyme. Such enzyme stabilizers include, for example, polyols such as propylene glycol, boric acid and borax. Combinations of these enzyme stabilizers may also be employed. If utilized, the enzyme stabilizers generally constitute from 0.1 to 1 wt % of the compositions.

The compositions may optionally comprise materials which serve as phase stabilizers and/or co-solvents. Examples are C₁-C₃ alcohols such as methanol, ethanol and propanol. C₁-C₃ alkanolamines such as mono-, di- and triethanolamines can also be used, by themselves or in combination with the alcohols. The phase stabilizers and/or co-solvents can, for example, constitute 0 to 1 wt %, preferably 0.1 to 0.5 wt %, of the composition.

The compositions may optionally comprise components which adjust or maintain the pH of the compositions at optimum levels. The pH may be from, for example, 1 to 13, such as 8 to 11 depending on the nature of the composition. For example a dishwashing composition desirably has a pH of 8 to 11, a laundry composition desirable has a pH of 7 to 9, and a water-softening composition desirably has a pH of 7 to 9. Examples of pH adjusting agents are NaOH and citric acid.

The above examples may be used for dish or fabric washing. In particular dish washing formulations are preferred which are adapted to be used in automatic dish washing machines. Due to their specific requirements specialised formulation is required and these are illustrated below

Amounts of the ingredients can vary within wide ranges, however preferred automatic dishwashing detergent compositions herein (which typically have a 1% aqueous solution pH of above 8, more preferably from 9.5 to 12, most preferably from 9.5 to 10.5) are those wherein there is present: from 5% to 90%, preferably from 5% to 75%, of builder; from 0.1% to 40%, preferably from 0.5% to 30%, of bleaching agent; from 0.1% to 15%, preferably from 0.2% to 10%, of the surfactant system; from 0.0001% to 1%, preferably from 0.001% to 0.05%, of a metal-containing bleach catalyst; and from 0.1% to 40%, preferably from 0.1% to 20% of a water-soluble silicate. Such fully-formulated embodiments typically further comprise from 0.1% to 15% of a polymeric dispersant, from 0.01% to 10% of a chelant, and from 0.00001% to 10% of a detersive enzyme, though further additional or adjunct ingredients may be present. Detergent compositions herein in granular form typically limit water content, for example to less than 7% free water, for better storage stability.

Non-ionic surfactants useful in ADW (Automatic Dish Washing) compositions of the present invention desirably include surfactant(s) at levels of from 2% to 60% of the composition. In general, bleach-stable surfactants are preferred. Non-ionic surfactants generally are well known, being described in more detail in Kirk Othmer's Encyclopedia of Chemical Technology, 3rd Ed., Vol. 22, pp. 360-379, “Surfactants and Detersive Systems”, incorporated by reference herein.

Preferably the ADW composition comprises at least one non-ionic surfactant. One class of non-ionics are ethoxylated non-ionic surfactants prepared by the reaction of a monohydroxy alkanol or alkylphenol with 6 to 20 carbon atoms with preferably at least 12 moles particularly preferred at least 16 moles, and still more preferred at least 20 moles of ethylene oxide per mole of alcohol or alkylphenol.

Particularly preferred non-ionic surfactants are the non-ionic from a linear chain fatty alcohol with 16-20 carbon atoms and at least 12 moles particularly preferred at least 16 and still more preferred at least 20 moles of ethylene oxide per mole of alcohol.

According to one preferred embodiment the non-ionic surfactant additionally comprise propylene oxide units in the molecule. Preferably this PO units constitute up to 25% by weight, preferably up to 20% by weight and still more preferably up to 15% by weight of the overall molecular weight of the non-ionic surfactant. Particularly preferred surfactants are ethoxylated mono-hydroxy alkanols or alkylphenols, which additionally comprises polyoxyethylene-polyoxypropylene block copolymer units. The alcohol or alkylphenol portion of such surfactants constitutes more than 30%, preferably more than 50%, more preferably more than 70% by weight of the overall molecular weight of the non-ionic surfactant.

Another class of non-ionic surfactants includes reverse block copolymers of polyoxyethylene and polyoxypropylene and block copolymers of polyoxyethylene and polyoxypropylene initiated with trimethylolpropane.

Another preferred non-ionic surfactant can be described by the formula:
R¹O[CH₂CH(CH₃)O]_X[CH₂CH₂O]_Y[CH₂CH(OH)R²]
wherein R¹ represents a linear or branched chain aliphatic hydrocarbon group with 4-18 carbon atoms or mixtures thereof, R² represents a linear or branched chain aliphatic hydrocarbon rest with 2-26 carbon atoms or mixtures thereof, x is a value between 0.5 and 1.5 and y is a value of at least 15.

Another group of preferred nonionic surfactants are the end-capped polyoxyalkylated non-ionics of formula:
R¹O[CH₂CH(R³)O]_x[CH₂]_kCH(OH)[CH₂]_jOR²
wherein R¹ and R² represent linear or branched chain, saturated or unsaturated, aliphatic or aromatic hydrocarbon groups with 1-30 carbon atoms, R³ represents a hydrogen atom or a methyl, ethyl, n-propyl, iso-propyl, n-butyl, 2-butyl or 2-methyl-2-butyl group, x is a value between 1 and 30 and, k and j are values between 1 and 12, preferably between 1 and 5. When the value of x is ≧2 each R³ in the formula above can be different. R¹ and R² are preferably linear or branched chain, saturated or unsaturated, aliphatic or aromatic hydrocarbon groups with 6-22 carbon atoms, where group with 8 to 18 carbon atoms are particularly preferred. For the group R³H, methyl or ethyl are particularly preferred. Particularly preferred values for x are comprised between 1 and 20, preferably between 6 and 15.

As described above, in case x≧2, each R³ in the formula can be different. For instance, when x=3, the group R³ could be chosen to build ethylene oxide (R³═H) or propylene oxide (R³=methyl) units which can be used in every single order for instance (PO)(EO)(EO), (EO)(PO)(EO), (EO)(EO)(PO), (EO) (EO) (EO), (PO) (EO) (PO), (PO) (PO) (EO) and (PO)(PO)(PO). The value 3 for x is only an example and bigger values can be chosen whereby a higher number of variations of (EO) or (PO) units would arise.

Particularly preferred end-capped polyoxyalkylated alcohols of the above formula are those where k=1 and j=1 originating molecules of simplified formula:
R¹O[CH₂CH(R³)O]_xCH₂CH(OH)CH₂OR²

The use of mixtures of different non-ionic surfactants is particularly preferred in ADW formulations for example mixtures of alkoxylated alcohols and hydroxy group containing alkoxylated alcohols.

The packages may themselves be packaged in outer containers if desired, for example non-water soluble containers which are removed before the water-soluble packages are used.

In use one or more packages are simply added to water where the outside dissolves. Thus they may be added in the usual way to a dishwasher or laundry machine, especially in the dishwashing compartment or a drum. They may also be added to a quantity of water, for example in a bucket or trigger-type spray.

EXAMPLE

Aquafilm L 330 cold water soluble film was used as the top sheet, 50 microns in thickness. The film was heated in the equipment used. The equipment used was a “Zappe” semi automatic skin packing apparatus, and heating took place for 7 seconds. The base sheet was also Aquafilm L 330 at 50 microns but punctured with small holes (approx. 0.2 mm diam.) over its entire surface at 25 mm intervals. This was then laid on a pourous carton board which in turn was placed on the suction platten of the machine. Six commercially available dish wash tablets were placed equally spaced on the base film. The machine cycle was operated using a vacuum of 850 mbar for 10 seconds to bring the heated top sheet onto and sealed to the bottom sheet. Good, tightly wrapped samples were produced.

Claims

1. A process for the preparation of a water-soluble package containing a compacted particulate composition, comprising:

a. placing a compacted particulate composition on a planar first water-soluble film;

b. positioning a second water-soluble film over said composition; and

c. sealing said first water-soluble film to said second water-soluble film and at least partly evacuating the atmosphere from the inside of said package so as to allow said first water-soluble film and said second water-soluble film to cling to said composition.

2. A process according to claim 1 wherein the atmosphere is at least partly evacuated from the inside of said package via a conduit and removing said conduit while or after said films are sealed together.

3. A process according to claim 1 wherein the atmosphere is at least partly evacuated from the inside of said package by applying suction to at least one hole in said first film and/or said second film.

4. A process according to claim 1 wherein the atmosphere is at least partly evacuated from the inside of said package by sealing said first film to said second film under a vacuum.

5. A process according to claim 1 wherein the package is made by a skin-wrapping process or a drape forming process.

6. A process according to claim 1 wherein said first film and said second film are sealed together by heat sealing.

7. A process according to claim 1 wherein said first polymer is a poly(vinyl alcohol).

8. A process according to claim 1 wherein said second polymer is a poly(vinyl alcohol).

9. A process according to claim 1 wherein the compacted particulate composition has a surface roughness Ra of from 10 to 20 μm.

10. A process according to claim 1 wherein the particulate composition is a fabric care, surface care or dishwashing composition.

11. A process according to claim 10 wherein the composition is a dishwashing, water-softening, laundry, detergent or rinse aid composition.

12. A process according to claim 1 wherein the composition is a disinfectant, antibacterial or antiseptic composition.

13. A process according to claim 1 wherein the composition is an agricultural composition.