Self-Disinfecting Face Shield
An article with self-disinfecting and anti-fog properties. In embodiments, the article is a face shield having a transparent substrate configured to extend facing at least a portion of a face of a wearer, and has a first surface adapted to be disposed facing the face of the wearer and second surface disposed opposite to the first surface. The face panel is protected by a sulfonated polymeric layer on the second surface, for killing at least 95% microbes within 30 minutes of contact. The sulfonated polymeric is sufficiently or selectively sulfonated to contain from 10-100 mol % sulfonic acid or sulfonate salt functional groups based on the number of monomer units, for killing at least 99% of microbes within 5 minutes of coming into contact with the face panel. The sulfonated polymeric layer has a Tfog of >15 minutes.
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This application is a continuation-in-part of PCT Application No. PCT/US2021/070409, filed on Apr. 19, 2021, which claims the benefit of provisional application No. 63/011,576 with a filing date of Apr. 17, 2020, No. 63/019,634 with a filing date of May 4, 2020, and No. 63/145,801 with a filing date of Feb. 4, 2021. This application also claims benefit to U.S. provisional application No. 63/374,775, filed on Sep. 7, 2022. All above patent applications are incorporated herein by reference.
TECHNICAL FIELDThe disclosure relates to a self-disinfecting face shield, having a protective antimicrobial layer.
BACKGROUNDWith the spread of contagious diseases, such as, COVID 19, it becomes necessary to protect people and prevent the people from coming into contact with diseases spreading microbes, e.g., viruses, bacteria, etc. Generally, people use face shields or face masks to prevent inhalation or entry of microbes. However, microbes such as viruses or bacteria would accumulate on an outer surface of the face shield, and may remain active for relatively long duration. These viruses or bacteria may contact the hands of the wearer, when the wearer removes the face shield, and subsequently may find their way inside the human body, which is undesirable.
There is still a need for improved face shields that prevents accumulation of active viruses or bacteria on its surface.
SUMMARYIn a first aspect, a self-disinfecting face shield is disclosed. The face shield comprises: a transparent face panel configured to extend facing at least a portion of a face of a wearer, the transparent face panel comprising a substrate having a first surface adapted to be disposed facing the face of the wearer and second surface disposed opposite to the first surface. At least one of first surface and the second surface is protected by a sulfonated polymeric layer for killing at least 90% microbes within 120 minutes of contact with the transparent face panel. The sulfonated polymeric layer comprises, or consists essentially, or consists of a sulfonated polymer, the sulfonated polymer from the group of perfluorosulfonic acid polymers, polystyrene sulfonates, sulfonated block copolymers, sulfonated polyolefins, sulfonated polyimides, sulfonated polyamides, sulfonated polyesters, sulfonated polysulfones, sulfonated polyketones, sulfonated poly(arylene ether), and mixtures thereof. The sulfonated polymeric layer has a thickness of at least >1 μm.
In some aspects, the sulfonated polymeric layer comprises at least 50 wt. %, more preferably at least 70 wt. %, even more preferably at least 90 wt. %, yet more preferably at least 95 wt. %, still more preferably at least 98 wt. %, even more preferably at least 99 wt. % and most preferably 100 wt. % (i.e. consists) of one or more of the sulfonated polymers.
In some aspects, the sulfonated polymer is a selectively sulfonated negative-charged anionic block copolymer, having at least one alkenyl arene polymer block A and at least one substantially completely, hydrogenated conjugated diene polymer block B, with substantially all of the sulfonic functional groups grafted to alkenyl arene polymer block A for the block A to be a hydrophilic end-block.
In some aspects, the sulfonated polymeric layer is applied onto the second surface by dip coating, spray coating, dispersion coating, solvent casting, or adhesively attached to the second surface as a peel-and-stick film.
In some aspects, the face shield further comprises an attachment structure coupled to the face panel and configured to secure the face panel in front of the face of the wearer.
In another aspect, an article comprising a substrate and a coating layer is provided on at least one surface of the substrate. The coating layer comprises a sulfonated styrenic block copolymer obtained by sulfonation of a styrenic block copolymer; wherein the styrenic block copolymer comprises a polymer block A selected from polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) alpha olefins of 3 to 18 carbon atoms, (iv) 1,3-cyclodiene monomers, (v) monomers of conjugated dienes having a vinyl content less than 35 mole % prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) mixtures thereof; a polymer block B of a vinyl aromatic monomer; and a polymer block D of a conjugated diene monomer; wherein at least one polymer block A, B, or D is sulfonated to obtain a degree of sulfonation of the sulfonated styrenic block copolymer of greater than 10 mole %, based on total weight of the sulfonated styrenic block copolymer. The article with the antifog coating layer has: a Tfog of greater than 8 seconds, measured at 40° C. steam test according to ANSI/ISEA Z87.1; and a yellowness index (ΔYI) of less than 4, according to ASTM E313; and wherein the coating layer has a thickness of at least >1 μm to kill at least 90% of microbes upon within 120 minutes of contact with the coating layer.
The following terms used the specification have the following meanings:
“At least one of [a group such as A, B, and C]” or “any of [a group such as A, B, and C]” means a single member from the group, more than one member from the group, or a combination of members from the group. For example, at least one of A, B, and C includes, for example, A only, B only, or C only, as well as A and B, A and C, B and C; or A, B, and C, or any other all combinations of A, B, and C. A list of embodiments presented as “A, B, or C” is to be interpreted as including the embodiments, A only, B only, C only, “A or B,” “A or C,” “B or C,” or “A, B, or C”.
“Effective amount” refers to an amount sufficient to alter, destroy, inactivate, and/or neutralize microbes, e.g., an amount sufficient to sterilize and kill microbes in contact with outer surface of the face panel in a face shield.
“Fogging” can be evaluated by directly breathing onto a face shield held approximately one inch from the mouth. Fogging is determined subjectively to be (i) “excellent if no fogging of the film was observed; (ii) fair if fogging is observed but dissipated within 2 seconds; or (iii) poor if fogging persisted more than 2 seconds. If excellent or fair, a coating is said to have anti-fogging properties. Anti-fog property can be expressed by Tfog, which is the time in minutes it takes to form a fog on a surface, e.g., exposing a layer (surface) to steam from boiling water at a 20 centimeter distance from the water's surface in an environment of 50% RH (relative humidity) and 22° C. For example, if the surface has a Tfog of 30 minutes, it means that no fog is formed on a surface of said coating within 30 minutes under the testing conditions described.
“Anti-fog” refers to the prevention or inhibition of build-up of condensation on a surface (e.g., lens, window, etc.). Anti-fog property can be expressed by the value Tfog, which is the time it takes to form a fog on a surface, i.e., time without fogging.
“Copolymer” refers to a polymer derived from more than one species of monomer.
“Block copolymer” refers to a copolymer that comprises more than one species of monomer, wherein the monomers are present in blocks. Each block is constituted of a set of monomer units different from the set of monomer of the connected surrounding blocks in the same block copolymer. Each block can be constituted of a homopolymer or a random copolymer.
“Polystyrene content” or PSC of a block copolymer refers to the weight % of vinyl aromatic, e.g., styrene in the block copolymer, calculated by dividing the sum of molecular weight of all vinyl aromatic units by the total molecular weight of the block copolymer. PSC can be determined using any suitable methodology such as proton nuclear magnetic resonance (NMR).
“Molecular weight” or Mw refers to the polystyrene equivalent molecular weight in g/mol of a polymer block or a block copolymer. Mw can be measured with gel permeation chromatography (GPC) using polystyrene calibration standards, such as is done according to ASTM 5296-19. The GPC detector can be an ultraviolet or refractive index detector or a combination thereof. The chromatograph is calibrated using commercially available polystyrene molecular weight standards. Mw of polymers measured using GPC so calibrated are polystyrene equivalent molecular weights or apparent molecular weights. Mw, expressed herein is measured at the peak of the GPC trace and are commonly referred to as polystyrene equivalent “peak molecular weights,” designated as Mp.
“Haze” means the percentage of transmitted light that upon passing through a specimen is scattered greater than 2.5 degrees from the normal. Haze and transmittance can be measured according to ASTM D1003 test method. A higher haze value indicates greater scattering.
“Ion Exchange Capacity” or IEC refers to the total active sites or functional groups responsible for ion exchange in a polymer. Generally, a conventional acid-base titration method is used to determine the IEC, see for example International Journal of Hydrogen Energy, Volume 39, Issue 10, Mar. 26, 2014, Pages 5054-5062, “Determination of the ion exchange capacity of anion-selective membrane.” IEC is the inverse of “equivalent weight” or EW, which the weight of the polymer required to provide 1 mole of exchangeable protons.
“Microbes” refers to microorganisms including bacteria, archaea, fungi (yeasts and molds), algae, protozoa, and viruses, with microscopic size.
“Peel-and-stick” or “peel-and-stick film” refers to a laminate having at least two layers, a release layer or liner which can also be a support layer, and another layer containing the sulfonated polymer. The peel-and-stick is self-adhesive, or releasable or peelable, or removable after being attached to a surface. The release layer is optionally coated with an adhesive which permits it to stick to a surface without glue, paste, or the like, allowing the peel-and-stick to be separable after being applied onto a surface. In embodiments, the layer containing the sulfonated polymer is optionally coated with an adhesive for the layer stick to surface, but is still releasable.
“Releasable” or “separable” bond in the context of layers or surfaces means that the layers or surfaces are generally attached or fastened to each other, yet can be separated with the application of a certain amount of force, and then subsequently refastened or reattached at a later time. In order to be “separable” or “releasable,” the surfaces must be capable of being fastened and separated, and the force applied to separate the layers or surfaces can be applied by hand.
“Surface pH” refers to the pH on the contact surface of the bio-secure material, that results from surface bound moieties e.g., the coating layer. The surface pH can be measured with commercial surface pH measuring instruments, e.g., SenTix™ Sur-electrode from WTW Scientific-Technical Institute GmbH, Weilheim, Germany.
The disclosure relates to articles such as face shields, eyewear, protective glasses, etc., having a protective antimicrobial layer that kills microbes within a predefined duration of contact. The face shield has a transparent panel with its surface (away from the wearer's face) being coated or protected with a layer comprising a self-sterilizing (self-disinfecting) sulfonated polymeric material with anti-fog properties. The portion of the face shield directed to the wearer can also be coated or protected with a self-sterilizing material, a sulfonated polymer. In embodiments, the protective material comprises, consists essentially of, or consists of a sulfonated polymer. The sulfonated polymer coats the surface of the transparent face panel for killing at least 95% microbes within a pre-defined duration of contact. In embodiments, the face shield includes an attachment structure to secure the transparent panel in front of the face of the wearer.
Self-sterilizing Material—Sulfonated Polymer: Sulfonated polymer refers to polymers having a sulfonate group, e.g., —SO3, either in the acid form (e.g., —SO3H, sulfonic acid) or a salt form (e.g., —SO3Na). The term “sulfonated polymer” also covers sulfonate containing polymers, e.g., polystyrene sulfonate.
The sulfonated polymer is selected from the group of perfluorosulfonic acid polymers (e.g., sulfonated tetrafluoroethylene), sulfonated polyolefins, sulfonated polyimides, sulfonated polyamides, sulfonated polyester, polystyrene sulfonates, sulfonated block copolymers, sulfonated polyolefins, sulfonated polysulfones such as polyether sulfone, sulfonated polyketones such as polyether ether ketone, sulfonated polyphenylene ethers, and mixtures thereof.
The sulfonated polymer is characterized as being sufficiently or selectively sulfonated to contain from 10-100 mol % sulfonic acid or sulfonate salt functional groups based on the number of monomer units or the block to be sulfonated (“degree of sulfonation”), to kill at least 95% of microbes within 120 minutes of coming into contact with the coating material. In embodiments, the sulfonated polymer has a degree of sulfonation of >25 mol %, or >50 mol %, or <95 mol %, or 25-70 mol %. Degree of sulfonation can be calculated by NMR or ion exchange capacity (IEC).
In embodiments, the sulfonated polymer is a sulfonated tetrafluoroethylene, having a polytetrafluoroethylene (PTFE) backbone; (2) side chains of vinyl ethers (e.g., —O—CF2—CF—O—CF2—CF2—) which terminate in sulfonic acid groups in a cluster region.
In embodiments, the sulfonated polymer is a polystyrene sulfonate, examples include potassium polystyrene sulfonate, sodium polystyrene sulfonate, a co-polymer of sodium polystyrene sulfonate and potassium polystyrene sulfonate (e.g., a polystyrene sulfonate copolymer), having a molecular weight of 20,000 to 1,000,000 Daltons, or >25,000 Daltons, or >40,000 Dalton, or >50,000, or >75,000, or >100,000 Daltons, or >400,000 Daltons, or <200,000, or <800,000 Daltons, or up to 1,500,000 Daltons. The polystyrene sulfonate polymers can either be crosslinked or uncrosslinked. In embodiments, the polystyrene sulfonate polymers are uncrosslinked and water soluble.
In embodiments, the sulfonated polymer is a polysulfone, selected from the group of aromatic polysulfones, polyphenylenesulfones, aromatic polyether sulfones, dichlorodiphenoxy sulfones, sulfonated substituted polysulfone polymers, and mixtures thereof. In embodiments, the sulfonated polymer is a sulfonated polyethersulfone copolymer, which can be made with reactants including sulfonate salts such as hydroquinone 2-potassium sulfonate (HPS) with other monomers, e.g., bisphenol A and 4-fluorophenyl sulfone. The degree of sulfonation in the polymer can be controlled with the amount of HPS unit in the polymer backbone.
In embodiments, the sulfonated polymer is a sulfonated polyether ketone. In embodiments, the sulfonated polymer is a sulfonated polyether ketone ketone (SPEKK), obtained by sulfonating a polyether ketone ketone (PEKK). The polyether ketone ketone can be manufactured using diphenyl ether and a benzene dicarbonic acid derivative. The sulfonated PEKK can be available as an alcohol and/or water-soluble product, e.g., for subsequent use to coat the face mask or in spray applications.
In embodiments, the sulfonated polymer is a sulfonated poly(arylene ether) copolymer containing pendant sulfonic acid groups. In embodiments, the sulfonated polymer is a sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), commonly referred to as sulfonated polyphenylene oxide. In embodiments, the sulfonated polymer is a sulfonated poly(4-phenoxybenzoyl-1,4-phenylene) (S-PPBP). In embodiments, the sulfonated polymer is a sulfonated polyphenylene having 2 to 6 pendant sulfonic acid groups per polymer repeat, and characterized as having 0.5 meq (SO3H)/g of polymer to 5.0 meq (SO3H)/g polymer, or at least 6 meq/g (SO3H)/g polymer.
In embodiments, the sulfonated polymer is a sulfonated polyamide, e.g., aliphatic polyamides such nylon-6 and nylon-6,6, partially aromatic polyamides and polyarylamides such as poly(phenyldiamidoterephthalate), provided with sulfonate groups chemically bonded as amine pendant groups to nitrogen atoms in the polymer backbone. The sulfonated polyamide can have a sulfonation level of 20 to up to 100% of the amide group, with the sulfonation throughout the bulk of the polyamide. In embodiments, the sulfonation is limited to a high density of sulfonate groups at the surface, e.g., >10%, >20%, >30%, or >40%, or up to 100% of the sulfonated amide group at the surface (within 50 nm of the surface).
In embodiments, the sulfonated polymer is a sulfonated polyolefin, containing at least 0.1 meq, or >2 meq, or >3 meq, or >5 meq, or 0.1 to 6 meq of sulfonic acid per gram of polyolefin. In embodiments, the sulfonated polymer is a sulfonated polyethylene. The sulfonated polyolefin can be formed by chlorosulfonation of a solid polyolefin obtained by polymerization of an olefin or a mixture of olefins selected from a group consisting of ethylene, propylene, butene-1,4-methylpentene-1, isobutylene, and styrene. The sulfonyl chloride groups can then be hydrolyzed, for example, in an aqueous base such as potassium hydroxide or in a water dimethylsulfoxide (DMF) mixture to form sulfonic acid groups. In embodiment, the sulfonated polyolefin is formed by submerging or passing polyolefin object in any form of powder, fiber, yarn, woven fabric, a film, a preform, etc., through a liquid containing sulfur trioxide (SO3), a sulfur trioxide precursor (e.g., chlorosulfonic acid, HSO3Cl), sulfur dioxide (SO2), or a mixture thereof. In other embodiments, the polyolefin object is brought into contact with a sulfonating gas, e.g., SO2 or SO3, or gaseous reactive precursor, or a sulfonation additive that evolves a gas SOx at elevated temperature.
The polyolefin precursor to be sulfonated can be, for example, a poly-α-olefin, such as polyethylene, polypropylene, polybutylene, polyisobutylene, ethylene propylene rubber, or a chlorinated polyolefin (e.g., polyvinylchloride, or PVC), or a polydiene, such as polybutadiene (e.g., poly-1,3-butadiene or poly-1,2-butadiene), polyisoprene, dicyclopentadiene, ethylidene norbornene, or vinyl norbornene, or a homogeneous or heterogeneous composite thereof, or a copolymer thereof (e.g., EPDM rubber, i.e., ethylene propylene diene monomer). In embodiments, the polyolefin is selected from low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), high density polyethylene (HDPE), medium density polyethylene (MDPE), high molecular weight polyethylene (HMWPE), and ultra-high molecular weight polyethylene (UHMWPE).
In embodiments, the sulfonated polymer is a sulfonated polyimide, e.g., aromatic polyimides in both thermoplastic and thermosetting forms, having excellent chemical stability and high modulus properties. Sulfonated polyimide can be prepared by condensation polymerization of dianhydrides with diamines, wherein one of the monomeric units contains sulfonic acid, sulfonic acid salt, or sulfonic ester group. The polymer can also be prepared by direct sulfonation of aromatic polyimide precursors, using sulfonation agents such as chlorosulfonic acid, sulfur trioxide and sulfur trioxide complexes. In embodiments, the concentration of sulfonic acid groups in the sulfonated polyimide as measured by ion exchange capacity, IEC, varying from 0.1 meq/g to above 3 meq/g, or at least 6 meq/g.
In embodiments, the sulfonated polymer is a sulfonated polyester, formed by directly sulfonating a polyester resin in any form, e.g., fiber, yarn, woven fabric, film, sheet, and the like, with a sulfuric anhydride-containing gas containing sulfuric anhydride, for a concentration of the sulfonate group on the surface of the polyester ranging from 0.1 meq/g to above 3 meq/g, e.g., up to 5 meq/g, or at least 6 meq/g.
In embodiments, the sulfonated polymer is a selectively sulfonated negative-charged anionic block copolymer. The term “selectively sulfonated” definition to include sulfonic acid as well as neutralized sulfonate derivatives. The sulfonate group can be in the form of metal salt, ammonium salt or amine salt.
Depending on the applications and the desired properties, the sulfonated polymer can be modified (or funcationalized). In embodiments, the sulfonated polymer is neutralized with any of various metal counterions, including alkali, alkaline earth, and transition metals, with at least 10% of the sulfonic acid groups being neutralized. In embodiments, the sulfonated polymer is neutralized with inorganic or organic cationic salts, e.g, those based on ammonium, phosphonium, pyridinium, sulfonium and the like. Salts can be monomeric, oligomeric, or polymeric. In embodiments, the sulfonated polymer is neutralized with various primary, secondary, or tertiary amine-containing molecules, with >10% of the sulfonic acid or sulfonate functional groups being neutralized.
In embodiments, the sulfonic acid or sulfonate functional group is modified by reaction with an effective amount of polyoxyalkyleneamine having molecular weights from 140 to 10,000. Amine-containing neutralizing agents can be mono-functional or multi-functional; monomeric, oligomeric, or polymeric. In alternative embodiments, the sulfonated polymer is modified with alternative anionic functionalities, such as phosphonic acid or acrylic and alkyl acrylic acids.
In embodiments, amine containing polymers are used for the modification of the sulfonated polymers, forming members of a class of materials termed coaservates. In examples, the neutralizing agent is a polymeric amine, e.g., polymers containing benzylamine functionality. Examples include homopolymers and copolymers of 4-dimethylaminostyrene which has been described in U.S. Pat. No. 9,849,450, incorporated herein by reference. In embodiments, the neutralizing agents are selected from polymers containing vinylbenzylamine functionality, e.g., polymers synthesized from poly-p-methylstyrene containing block copolymers via a bromination-amination strategy, or by direct anionic polymerization of amine containing styrenic monomers. Examples of amine functionalities for functionalization include but are not limited to p-vinylbenzyldimethylamine (BDMA), p-vinylbenzylpyrrolidine (VBPyr), p-vinylbenzyl-bis(2-methoxyethyl)amine (VBDEM), p-vinylbenzylpiperazine (VBMPip), and p-vinylbenzyldiphenylamine (VBDPA). In embodiments, corresponding phosphorus containing polymers can also be used for the functionalization of the sulfonated polymers.
In embodiments, the monomer or the block containing amine functionality or phosphine functionality can be neutralized with acids or proton donors, creating quaternary ammonium or phosphonium salts. In other embodiments, the sulfonated polymer containing tertiary amine is reacted with alkylhalides to form functional groups, e.g., quaternized salts. In some embodiments, the sulfonated polymer can contain both cationic and anionic functionality to form so-called zwitterionic polymers.
In some embodiments, the sulfonated polymer is a selectively sulfonated negative-charged anionic block copolymer, which “selectively sulfonated” definition to include sulfonic acid as well as neutralized sulfonate derivatives. The sulfonate group can be in the form of metal salt, ammonium salt or amine salt. In embodiments, the sulfonated block polymer has a general configuration A-B-A, (A-B)n(A), (A-B-A)nX, (A-B)nX, A-D-B, A-B-D, A-D-B-D-A, A-B-D-B-A, (A-D-B)nA, (A-B-D)nA (A-D-B)nX, (A-B-D)nX or mixtures thereof; where n is an integer from 0 to 30, or 2 to 20 in embodiments; and X is a coupling agent residue. Each A and D block is a polymer block resistant to sulfonation. Each B block is susceptible to sulfonation. For configurations with multiple A, B or D blocks, the plurality of A blocks, B blocks, or D blocks can be the same or different.
In embodiments, the A blocks are one or more segments selected from polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) alpha olefins of 3 to 18 carbon atoms; (iv) 1,3-cyclodiene monomers, (v) monomers of conjugated dienes having a vinyl content less than 35 mol percent prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) mixtures thereof. If the A segments are polymers of 1,3-cyclodiene or conjugated dienes, the segments will be hydrogenated subsequent to polymerization of the block copolymer and before sulfonation of the block copolymer. The A blocks may also contain up to 15 mol % of the vinyl aromatic monomers such as those present in the B blocks.
In embodiments, the A block is selected from para-substituted styrene monomers selected from para-methylstyrene, para-ethylstyrene, para-n-propylstyrene, para-iso-propylstyrene, para-n-butyl styrene, para-sec-butyl styrene, para-iso-butyl styrene, para-t-butylstyrene, isomers of para-decylstyrene, isomers of para-dodecylstyrene and mixtures of the above monomers. Examples of para-substituted styrene monomers include para-t-butylstyrene and para-methylstyrene, with para-t-butylstyrene being most preferred. Monomers may be mixtures of monomers, depending on the particular source. In embodiments, the overall purity of the para-substituted styrene monomers be at least 90%-wt., or >95%-wt., or >98%-wt. of the para-substituted styrene monomer.
In embodiments, the block B comprises segments of one or more polymerized vinyl aromatic monomers selected from unsubstituted styrene monomer, ortho-substituted styrene monomers, meta-substituted styrene monomers, alpha-methylstyrene monomer, 1,1-diphenylethylene monomer, 1,2-diphenylethylene monomer, and mixtures thereof. In addition to the monomers and polymers noted, in embodiments the B blocks also comprises a hydrogenated copolymer of such monomer (s) with a conjugated diene selected from 1,3-butadiene, isoprene and mixtures thereof, having a vinyl content of between 20 and 80 mol percent. These copolymers with hydrogenated dienes can be any of random copolymers, tapered copolymers, block copolymers or controlled distribution copolymers. The block B is selectively sulfonated, containing from about 10 to about 100 mol % sulfonic acid or sulfonate salt functional groups based on the number of monomer units. In embodiments, the degree of sulfonation in the B block ranges from 10 to 95 mol %, or 15-80 mol %, or 20-70 mol %, or 25-60 mol %, or >20 mol %, or >50 mol %.
The D block comprises a hydrogenated polymer or copolymer of a conjugated diene selected from isoprene, 1,3-butadiene and mixtures thereof. In other examples, the D block is any of an acrylate, a silicone polymer, or a polymer of isobutylene with a number average molecular weight of >1000, or >2000, or >4000, or >6000.
The coupling agent X is selected from coupling agents known in the art, including polyalkenyl coupling agents, dihaloalkanes, silicon halides, siloxanes, multifunctional epoxides, silica compounds, esters of monohydric alcohols with carboxylic acids, (e.g. methylbenzoate and dimethyl adipate) and epoxidized oils.
The antimicrobial and mechanical properties of the sulfonated block copolymer can be varied and controlled by varying the amount of sulfonation, the degree of neutralization of the sulfonic acid groups to the sulfonated salts, as well as controlling the location of the sulfonated group(s) in the polymer. In embodiments and depending on the applications, e.g., one with the need for water dispersity/solubility, or at the other spectrum, one with the need for sufficient durability with constant wiping with water based cleaners, the sulfonated block copolymer can be selectively sulfonated for desired water dispersity properties or mechanical properties, e.g., having the sulfonic acid functional groups attached to the inner blocks or middle blocks, or in the outer blocks of a sulfonated block copolymer, as in U.S. Pat. No. 8,084,546, incorporated by reference. If the outer (hard) blocks are sulfonated, upon exposure to water, hydration of the hard domains may result in plasticization of those domains and softening, allowing dispersion or solubility.
The sulfonated copolymer in embodiments is as disclosed in Patent Publication Nos. U.S. Pat. Nos. 9,861,941, 8,263,713, 8,445,631, 8,012,539, 8,377,514, 8,377,515, 7,737,224, 8,383,735, 7,919,565, 8,003,733, 8,058,353, 7,981,970, 8,329,827, 8,084,546, 8,383,735, 10,202,494, and 10,228,168, the relevant portions are incorporated herein by reference.
In embodiments, the sulfonated block copolymer has a general configuration A-B-(B-A)1-5, wherein each A is a non-elastomeric sulfonated monovinyl arene polymer block and each B is a substantially saturated elastomeric alpha-olefin polymer block, said block copolymer being sulfonated to an extent sufficient to provide at least 1% by weight of sulfur in the total polymer and up to one sulfonated constituent for each monovinyl arene unit. The sulfonated polymer can be used in the form of their acid, alkali metal salt, ammonium salt or amine salt.
In embodiments, the sulfonated block copolymer is a sulfonated polystyrene-polyisoprene-polystyrene, sulfonated in the center segment. In embodiments, the sulfonated block copolymer is a sulfonated t-butylstyrene/isoprene random copolymer with C═C sites in their backbone. In embodiments, the sulfonated polymer is a sulfonated SBR (styrene butadiene rubber) as disclosed in U.S. Pat. No. 6,110,616 incorporated by reference. In embodiments, the sulfonated polymer is a water dispersible BAB triblock, with B being a hydrophobic block such as alkyl or (if it is sulfonated, it becomes hydrophilic) poly(t-butyl styrene) and A being a hydrophilic block such as sulfonated poly(vinyl toluene) as disclosed in U.S. Pat. No. 4,505,827 incorporated by reference. In embodiments, the sulfonated block copolymer is a functionalized, selectively hydrogenated block copolymer having at least one alkenyl arene polymer block A and at least one substantially completely, hydrogenated conjugated diene polymer block B, with substantially all of the sulfonic functional groups grafted to alkenyl arene polymer block A (as disclosed in U.S. Pat. No. 5,516,831, incorporated by reference). In embodiments, the sulfonated polymer is a water-soluble polymer, a sulfonated diblock polymer of t-butyl styrene/styrene, or a sulfonated triblock polymer of t-butyl styrene—styrene—t-butyl styrene as disclosed in U.S. Pat. No. 4,492,785 incorporated by reference. In embodiments, the sulfonated block copolymer is a partially hydrogenated block copolymer.
In embodiments, the sulfonated polymer is a midblock-sulfonated triblock copolymer, or a midblock-sulfonated pentablock copolymer or, e.g., a poly(p-tert-butylstyrene-b-styrenesulfonate-b-p-tert-butylstyrene), or a poly[tert-butylstyrene-b-(ethylene-alt-propylene)-b-(styrenesulfonate)-b-(ethylene-alt-propylene)-b-tert-butylstyrene.
In embodiments, the sulfonated polymer contains >15 mol %, or >25 mol %, or >30 mol %, or >40 mol %, or >60 mol % sulfonic acid or sulfonate salt functional groups based on the number of monomer units in the polymer that are available or susceptible for sulfonation, e.g., the styrene monomers.
In embodiments, the sulfonated polymer has an ion exchange capacity of >0.5 meq/g, or >0.75 meq/g, or >1.0 meq/g, or >1.5 meq/g, or >2.0 meq/g, or >2.5 meq/g, or <5.0 meq/g.
Optional Additives: In embodiments, the sulfonated polymer further contains or can be complexed with, or otherwise form mixtures, compounds, etc. with, antibiotics such as butylparaben and triclosan, e.g., antimicrobial surfactants, lipids, nanoparticles, peptides, antibiotics or antiviral drugs, quaternary ammonium and phosphonium containing polymers, chitosan and other naturally occurring antimicrobial polymers, ion-exchange resins, metallic-based micro and nano-structured materials such as silver, copper, zinc and titanium and their oxides, for enhanced antimicrobial effectiveness.
In embodiments, the sulfonated polymer further comprises additives for decorative or safety effects, e.g., luminescent additives such as phosphorescent and fluorescence that would help or enable the sulfonated polymer layer to illuminate.
In embodiments, the optional additives are optical brighteners additives that illuminate under a special UV or black light tracer, allowing for physical inspections to verify that intended surfaces are coated or have remained intact, offering the intended antimicrobial/self-disinfecting effects.
In embodiments, the optical additives are UV stabilizers, e.g., UV absorbers, quenchers known in the art.
In embodiments, the sulfonated polymer further comprises additives that would help signal or give an indicator of its antimicrobial effects with a color change pH indicator. Examples include Thymol Blue, Methyl Orange, Bromocresol Green, Methyl Red, Bromothymol Blue, Phenol Red, and Phenol-phthalein. A color change means a change in hue, from a light to a darker color or vice versa. A color indicator may indicate if a recharge, regeneration, or reactivation of the antimicrobial activity of the protective layer is recommended. The color indicator is incorporated in a sufficient amount so that a noticeable change in color hue is observed immediately when there is a change in the effectiveness of the sulfonated polymeric material, e.g., when its surface pH is increased above 2.0. In embodiments, the amount of color indicator ranges from 0.1 to 20 wt. % of the amount of sulfonated polymer applied as a protective layer on the frequently-touched surface.
In addition to the above optional components, other additives such as plasticizers, tackifiers, surfactants, film forming additives, dyes, pigments, cross-linkers, UV absorbers, catalysts, highly conjugated particles, sheets, or tubes (e.g. carbon black, graphene, carbon nanotubes), etc. may be incorporated in any combination to the extent that they do not reduce the efficacy of the material.
Properties of Sulfonated Polymer: When applied as a thin protective layer, the sulfonated polymer is characterized as being transparent. Transparency refers to optical clarity, meaning that enough light is transmitted through to allow visualization through the film by an observer. Although some haze or coloration may be presented, such haze or coloration does not substantially interfere with visualization. In embodiments, an antimicrobial sulfonated polymeric layer has a transmission rate of at least 90%, or at least 91%; or clarity of at least 99% or 99.5%; or a haze value of <1.5%, or <1.25%, or <1.0%, or <0.75%. Haze can be measured according to ASTM D-1003. This is in comparison with clear acrylic layers having transmission of 94.5%, haze of 0.1, and clarity of 100%.
In embodiments, the sulfonated polymer is characterized as having anti-fogging properties, with a Tfog of >5 minutes, i.e., no fog is formed on a surface of substrates having sulfonated polymer coating within about 5 minutes. In embodiments, the Tfog is >15 minutes, or >30 minutes.
In embodiments, the sulfonated polymer is characterized as being sufficiently sulfonated to have an IEC of >0.5 meq/g, or 1.5-3.5 meq/g, or >1.25 meq/g, or >2.2 meq/g, or >2.5 meq/g, or >4.0 meq/g, or <4.0 meq/g.
In embodiments, the sulfonated polymer is characterized as having a surface pH of <3.0, or <2.5, or <2.25, or <2.0, or <1.80. It is believed that a sufficiently low surface level, as a result of the presence of sulfonic acid functional groups in the protective layer, would have catastrophic effects on microbes that come in contact with the surface.
In embodiments, the sulfonated polymer works effectively in destroying/inactivating at least 99%, or at least 99.5%, or at least 99.9% of microbes in <30 minutes of exposure, or <5 minutes of exposure or contact with microbes, including but not limited to MRSA, vancomycin-resistant Enterococcus faecium, X-MulV, PI-3, SARS-CoV-2, carbapenem-resistant Acinetobacter baumannii, and influenza A virus. In embodiments with polymer containing quaternary ammonium group, the material is effective in killing target microbes including Staphylococcus aureus, Escherichia coli, Staphylococcus albus, Escherichia coli, Rhizoctonia solani, and Fusarium oxysporum. The sulfonated polymer remains effective in killing microbes even after 4 hours, or after 12 hours, or at least 24 hours, or for at least 48 hours.
In embodiments, the sulfonated polymer is a sulfonated block copolymer, e.g., a midblock-sulfonated pentablock copolymer, containing >40 mol % sulfonic acid or sulfonate salt functional groups based on the number of monomer units. In tests simulating cleaning of the surface of a sulfonated polymeric film, after 2400 cleaning or abrasion cycle, representing 200 days (at least 6 months) in use with 6 cleaning sessions per day (with 4 rubbing motions per session with alcohol and/or quaternary ammonium compounds cleaners).
Methods for Applying Protective Layer: The sulfonated polymer can be applied as a protective coating on the transparent substrate of the article, e.g., a face shield panel or eyewear lenses as a coating, or as a self-adhesive protective film. The sulfonated polymer can be applied onto the substrate before or after it is made into the article such as face panel, and before or after the transparent anti-fog substrate is incorporated into the article, for a protective layer having a thickness of <1000 μm, or >1 μm, or >5 μm, or >10 μm, or <500 μm, or <200 μm, or <100 μm, or 1 to 1000 μm, or 1 to 500 μm, or 1 to 200 μm, or 1 to 100 μm for a self-sterilizing, anti-fog surface.
The base or substrate is formed from a variety of materials. Examples include, but are not limited to, polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonates, allyl diglycolcarbonates, polyacrylates, such as polymethyl methacrylate, polystyrenes, cellulose acetate butyrate, glass, and combinations thereof. The substrate can be any of a film, sheet, panel or pane of material, formed by known processes, such as blowing, casting, extrusion, injection molding, etc. The thickness of the substrate is such that it is stiff enough to prevent collapse, yet flexible enough to bend, e.g., from 0.001 to 2 mm, or 0.01 to 0.5 mm, or 0.1-0.4 mm, or <0.5 mm, or at least 0.05 mm.
In embodiments, the sulfonated polymer material is dispersed in a solvent in an amount up to 10 wt. %, or up to 20 wt. %, or up to 50 wt. %, 5-30, or 10-25, or 10-20 wt. %, based on the total weight of the solvent, for application in a pourable form, sprayable form, or impregnated into an applicator substrate, e.g., forming an applicator pad or wipe, for coating the base substrate as a protective layer. Examples of coating processes include dipping, flow coating, roll coating, bar coating, spray coating, curtain, rotogravure, brushing, wire wound rod coating, pan fed reverse roll coating, nip-fed coating, spraying, knife coating, spin coating, immersion coating, slot-die coating, ultrasonic spray coating, and the like.
Depending on the sulfonated polymer used, exemplary solvents include but are not limited to methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, diacetone alcohol and other alcohol solvents, ethylene glycol monomethyl ether, ethylene glycol monethylether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxy-1-butanol, 3-methoxy-3-methyl-1-butanol, other alcohol ether solvent, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, other ketone solvents, tetrahydrofuran, dioxane, methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, ethyl lactate, benzene, toluene, xylene, formamide, dimethyl formamide, n-hexane, cyclohexane, n-heptane, n-octane, n-decane, and other hydrocarbon solvents; and mixtures thereof. In embodiments, the solvent is a “green solvent” such as 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, 2-propanol, methyl ethyl ketone, 1-butanol, tert-butanol, and mixtures thereof. In embodiments, the sulfonated polymer is applied by preparing a solution of the polymer in a suitable solvent, then casting on the substrate to be subsequently formed into face panels, with the thickness of the protective polymeric layer being adjusted with a casting knife, followed by drying.
In embodiments, the protective sulfonated polymeric layer is formed on the face panel by methods including but not limited to spray coating, or dip coating the substrate into a solution or dispersion containing the sulfonated polymer. Multiple coatings can be applied sequentially. In embodiments, the composition dispersed in a solvent can be made into a film or applied as coating layer by methods known in the art, e.g., spraying, spin coating, brushing, dipping, flow coating, etc. The coating layer can be done in single stage or a multi-stage coating. In embodiments, the sulfonated polymeric composition is deposited on to the substrate by soaking a cloth, or tissue paper, woven/non-woven object in the coating composition and then used for wiping the surface to obtain a self-sterilizing, anti-fog coating layer. The articles, such as face panels, eyewear, etc., can be coated with the sulfonated polymeric material as individual pieces, or they can be formed from a large piece of coated substrate, cut into shapes forming the article.
In embodiments, the sulfonated polymeric layer is applied on the substrate as a peel-and-stick film. The peel-and-stick film is first peeled off to remove an optional support/release liner if present, and then applied directly onto the base substrate as a protective layer. After the film is positioned on the substrate, a squeegee or slight tap of finger may be used to remove trapped air between the film and the substrate. After a period of time of use as a protective layer cover for the article, the releasable peel-and-stick with the sulfonated polymeric protective layer can be peeled off, and replaced with a new peel-and-stick film for protection.
In embodiments with the use of sulfonated polymeric material with anti-fog properties (e.g., having Tfog of >15, or >30 minutes), the sulfonated polymeric material is used to coat both sides of a transparent substrate, e.g., the outer surface of a face panel, as well as the inner surface facing the wearer to minimize fog formation for extent wearing.
Applications: It should be noted that besides face shields, an article having the self-sterilizing anti-fog properties can be in many other forms, such as automotive interior glass, windshield, shower enclosures, underwater face masks and glasses, protective glasses, helmets, face shields, refrigerator doors, packaging films (e.g., food, vegetables, or products which release moisture, etc.), eyeglasses, lenses, optical parallel plates, diving masks, microscope, telescope, prisms, mirrors (e.g., mirrors for use in dental clinics etc.), and the like.
Depending on the applications, the substrate of the article to be coated with the self-sterilizing, anti-fog layer can have a thickness ranging from microns to centimeter ranges, e.g., 10 μm-5 cm, or 100 μm-10 mm, or 500 μm-2 mm. If the substrate is being used for food or vegetable packaging in the form the film, the thickness of the substrate can be in the range of 1-500 μm, or 10-400 μm, or 20-100 μm.
Properties of the self-sterilizing, anti-fog layer: In addition to the self-sterilizing properties, the coating layer can be transparent or colored, and exhibit excellent antifog properties, adhesion to the substrate, heat resistance, scratch resistance, chemical resistance, water sensitivity, moisture resistance, peel resistance, durability, and antireflective property. The coating layer on the substrate does not reduce the clarity or transparency of the substrate and has durability of several weeks, e.g., >1, or >2, or >4, or >6 weeks.
In embodiments, the layer has a surface pH of <8, or <7 or, <6, or <5, or <4, or <3, or <2.75, or <2.5, or <2.25, or <2, or <1.75, or <1.5, or <1.25.
In embodiments, the layer when applied on the film for food/vegetable packaging applications, has a durability of >8, or >15, or >24, or >48 hrs.
In embodiments, the layer has a thickness of 1-100 μm, or 2-80 μm, or 5-50 μm, or >1 μm, or <40 μm.
In embodiments, the layer has a Tfog of >8, >20, or >25, or >30, or 35, or >45 seconds, or >1 minute.
In embodiments, the article containing layer has a yellowness index (ΔYI) of <5, or <4, or <3, or <2.5, or <2, or <1.5, or <1.
In embodiments, the substrate containing the layer, has a surface energy value of >20, or >30, or >35, or >40, or >45, or >50 dyne/cm.
In embodiments, an abrasion resistant of the layer was measured according to ASTM D1044 (haze). The layer has a haze variation (ΔH) from haze (Hb) before the test to haze (Ha) after the test is <5%, or <4.5%, or <4%, or <3.5%, or <3%, or <2%.
In embodiments, the substrate containing the layer has a transmittance of >80, or >85, or >88, or >90, or >92, or >94%. In embodiments, the layer has a haze value of <3, or <2, or <1.5, or <1.25, or <1.0, or <0.75. In embodiments, the layer has a clarity of >90, or >92, or >94, or >99, or 99.5%.
The coating layer when deposited on a plastic film, e.g., PET film, can have a desirable oxygen transmission rate suitable for food, or vegetable packaging applications. In embodiments, the layer on the plastic film has an oxygen transmission rate of 1000-20000, or 1500-18000, or 2000-15000, or 5000-12000 cc/m2/24 hrs.
Reference will be made to the figures, showing various embodiments of the face shields, with different embodiments of attachment structures.
The first and second polymeric films can be the same or different sulfonated polymers. In embodiments, the second polymeric film 152 comprises a sulfonated block copolymer material from Kraton Corporation with anti-fogging properties, allowing the wearer to better see through the face panel 102. In embodiments, additional “fresh” or new layers of sulfonated polymeric film can be applied onto the first polymeric film as time goes on, for the face shield to continue functioning as a self-sterilizing protective gear.
Face shield 100 may include an attachment structure 120 for securing the face panel 102 to the wearer 200, is adapted to position the face panel 120 in front of the face of wearer 200. The attachment structure 120 is adapted to secure the face shield 100 to the wearer's head, and includes a first strap 122 connected to the face panel 102 at a location proximate to the first side edge 108 and the top edge 102, and a second strap 124 connected to the face panel 102 at allocation proximate to the second side edge 110 and the top edge 102. The attachment structure 120 includes a coupler 126 for attaching the first strap 122 to the second strap 124.
In an embodiment, the coupler 126 may include a male member 128 attached to the first strap 122 and a female member 130 attached to the second strap 124 and adapted to removably engage with the male member 128. In some embodiments (not shown), the coupler 120 may be a hook and loop assembly having a hook member attached to the first strap 122 and a loop member attached to the second strap 124. In an embodiment (not shown), the first strap 122 and the second strap 124 may be adhesively attached to an inner surface 136 of the face panel 102. In some embodiments (not shown), the face panel 102 may include cut-outs extending from the inner surface 136 to the outer surface and arranged proximate to the side edges 108, 110, and the straps 122, 124 may be attached to the face panel 102 by inserting a portion of each of the straps 122, 124 through respective cut-outs and then making a knot. It may be appreciated that the straps 122, 124 may be attached to the face panel 102 by any mechanism or methods known in the art.
In embodiments (not shown), the attachment structure 120 may be a simple elastic strap with one end attached or tied to or near the top of the first side edge 108, and with the other end being attached or tied to or near the top of the second side edge 110.
In some embodiments (not shown), the face panel 102 may be built-in as part of a protective garment, such as, personal protective equipment.
The frame 504 includes a first arc portion 530 extending from the bridge 520 to the first temple 508, and a second arc portion 532 extending from the bridge 520 to the second temple 510. The face panel 506 may be attached to the two arc portions 530, 532 such that the bridge 520, the nose pads 522, 524, and the arc portions 530, 532 are arranged between the face of the wearer 200 (not shown) and the face panel 506. The two temples 508, 510 are adapted to rest on the ears of the wearer 200 to secure the face shield on the wearer 200. The one or more or the bridge 520, the nose pads 522, 524, and the arc portions 530, 532 may abut the inner surface of the face panel 506, and may be engaged/attached with the face panel 506. In an embodiment, the frame 504 and the face panel 506 may be integrally formed. Alternatively, the face panel 506 may be removably engaged with the frame 504. Additionally, or optionally, the face shield 500 may include cushion pads (not shown) engaged with any of the arc portions 530, 532 and the bridge 520, and are adapted to contact the periphery of the eyes and the nose of the wearer 200 to provide cushioning effect.
The eyeglasses include two temples or arms 608, 610 (not shown in
Optionally, the eyeglass 604 may include a cushion pad 638 engaged with the rim portions 630, 632 and the bridge 620 and is adapted to contact, or seal around the periphery of the eyes and the nose of the wearer 200 to provide cushioning effect. It should be noted that the lenses 634 and 636 can also be protected or coated with a layer of the sulfonated polymer.
In embodiments (not shown), the face panel 102 includes a nose cavity and/or a cushion for the face panel to rest upon the nose of the wearer. In yet other embodiments (not shown), the first and second arms are shaped such that they fit around the ear lobes of the wearer, keeping the face shield secure for protecting the wearer's face.
Attachment structure 902 includes a cap 920 adapted to be arranged over the head of the wearer 200, and may include a retention structures, for example, a first retention structure 922 and a second retention structure (not shown) adapted to engage with the engagement structures of the first arm 902 and the second arm. Retention structure 922 may be protrusion 924 extending outwardly from the cap 920. First arm 902 and the second arm may be engaged with the cap 920, such that the protrusions 924 extend through the respective hole 912, for the face panel 906 to be supported on the respective protrusions 924 such that the face panel 906 can be pivoted relative to the cap 920 between a first position (e.g. upward position) and a second position (e.g. downward position). The face panel 906 is formed or contoured corresponding to a profile of the face of the wearer 200.
In embodiments (not shown), the face panel of the face shield covers only the nose and mouth. The face shield has two adjustable arms or temples, as similar to eye glasses, that wrap around a wearer's ears.
The patentable scope is defined by the claims, which include other examples that occur to those skilled in the art and may not have been illustrated by the Figures, e.g., a face shield with a removable transparent face panel, which can be removed and replaced with another face panel, or face shield that can be clipped onto an eyeglass frame, or a face shield having hook-and-loop fastener assembly (e.g., Velcro) straps for use as an attachment structure for the face shield. The face shield can also be one-piece with the attachment structure being integral with the substrate which forms the face panel, or a face shield connected to a protective garment to be worn by the user, a face shield being an integrated part of the head gear of a protective garment, or a removable face panel for insertion into a protective garment, or a protective head gear, or for attaching to a cap or a hat (e.g., with a hook-and-loop fastener such as Velcro).
Examples: The following examples are intended to be non-limiting.
The following test methods are used.
Antifog test: Antifog performance was measured according to ANSI/ISEA Z87.1 2020 (American National Standard Institute/International Safety Equipment Association)/ASTM F659-10.
The yellowness index was calculated according to ASTM E313.
Taber abrasion was measured according to ASTM D1044.
For moisture resistance, the article with antifog coating layer where no peeling occurs after the 2000 hrs. holding in a 50° C. and 95% relative humidity thermohygrostat was evaluated as having moisture resistance. The presence/absence of the peeling was visually confirmed.
For an acid resistance test, the article with antifog coating layer where no peeling occurs after three-hrs. immersion in a 21 to 25° C., 0.1 N nitric acid aqueous solution was evaluated as having acid resistance.
Pencil Hardness of the article having the antifog coating layer was measured according to ASTM D3363.
Dry Adhesion Test (Cross-hatch Test): Dry adhesion of the antifog coating layer was measured using the cross-hatch adhesion test according to ASTM D3359-93.
The components used in examples include:
SSBC-1 is a solution of the sulfonated styrene-ethylene/butylene-styrene polymer in cyclohexane solvent with the concentration of about 10%. The polymer has the IEC of 2.0 meq/g, the polystyrene content of about 35%, the molecular weight (Mr) of about 70000 g/mol, and the degree of sulfonation of about 68-70%.
SSBC-1H is obtained by casting the solution of SSBC-1 and then drying to obtain the solid polymer, termed as SSBC-1H.
SSBC-1TP is obtained by dissolving SSBC-1H in toluene/propanol (50:50) solvent mixture and casting this solution followed by drying to obtain the solid polymer, termed as SSBC-1TP.
Comp-1 is a transparent polyester film of about 170 μm thickness and having antifog properties on both sides, available from 3M™ as 9960.
Comp-2 is a transparent polyester film of about 90 μm thickness and having antifog properties on both sides, available from 3M™ as 9962.
Comp-3 is a disposable full-length face shield having antifog properties, available from TIDI.
Example 1: Tests were conducted to evaluate antimicrobial efficacy & the long-lasting antiviral properties of sulfonated polymers, film samples of sulfonated penta block copolymer (SPBC) of the structure poly[tert-butylstyrene-b-(ethylene-alt-propylene)-b-(styrene-co-styrene-sulfonate)-b-(ethylene-alt-propylene)-tert-butylstyrene] with 52% sulfonation were cast out of 1:1 mixture of toluene and 1-propanol. The sulfonated polymer film samples were subjected to abrasion testing of 2200 cycles in the presence of 3 common disinfectants: 1) 70% ethanol, benzalkonium chloride, and quaternary ammonia], and exposure to SARS-CoV-2 virus suspension of concentration 107 pfu/ml.
After 2 hours of contact, viable virus was recovered from each sample by washing twice with 500 μl of DMEM tissue culture media containing 10% serum, and measured by serial dilution plaque assay. Gibco Dulbecco's Modified Eagle Medium (DMEM) is a basal medium for supporting the growth of many different mammalian cells. The results demonstrate that, after abrasion testing representing approximately one year of cleaning (6 disinfectant wipes/day), there is a reduction in virus count of >99%.
Example 2: In this example, a multi-layer laminate is structured by casting a sulfonated block polymer solution (sulfonated block polymers in toluene/1-propanol at a 1:1 ratio) onto a Mylar sheet of 1 mil (25.4 μm) thick.
The casting is done on a mechanical casting table with a casting blade, e.g., Elcometer 4340, that controls the thickness, and the speed of solution being casted on a substrate. A set amount of sulfonated polymer, depending on the desired thickness, is poured onto a substrate. A casting blade is pulled over the liquid, creating a uniform thickness over a substrate. The material is next placed in a chamber where the solvent can be slowly evaporated. After all the solvent is evaporated, the casting is complete forming a laminate structure having thickness ranging from 0.0176 inches (0.044 cm) to 0.0003 inches (0.00076 cm).
Surface pH of the antimicrobial layer is measured using a surface pH measuring probe (EDT DirectION Limited model E8087). For the pH test, a small drop of water around 0.02 ml of water is placed on the antimicrobial layer. The probe is placed on top of the water drop and is touched to the surface of the layer, and pH is measured after 5 minutes, giving a pH of 2.0.
Example 3. A polyethylene flat sheet of 0.5 mm thick is chlorosulfonated by immersing for six hours at room temperature in a sulfur dioxide/chlorine gas mixture (3:1 volume ratio) in visible light. The chlorosulfonated polyethylene sheet is then immersed in 1N NaOH at 50° C. for two days to hydrolyze the pendant sulfonyl chloride groups (—SO2Cl) groups to sulfonic groups (—SO3Na+). The sulfonic acid form is obtained by treating the sheet with 1N HCl at room temperature for four hours. The sheet is then washed with deionized water and dried under vacuum. The milli-equivalence (meq) of sulfonic acid groups per gram of polyethylene is determined by titration with NaOH and found to be 1.69 meq/g. The sulfonated polyethylene sheet can be cut into appropriate sizes for the protection of surfaces.
Example 4. Dichloromethane (50 mL, 66 gm) and chlorosulfonic acid (between 0.7 and 1.4 gms) are added sequentially to a wide mouth glass bottle (120 mL capacity, 2 inch diameter). 10 mL of this solution are added to dichloromethane (50 mL, 66 gms) in a wide mouth glass jar (410 mL, 3 inch diameter). To this mixture is added a 1 mil (0.001 inch, 0.0025 cm) colorless PPS (Polyphenylene Sulfide) film. The film is allowed to react for various amounts of time at 25° C. while being suspended in the reaction solution. After a variable time of reaction, the black film is then added to distilled water (200 mL) and the film turned light yellow. The film is washed extensively with more water (about 2 liter) and then boiled in water (250 mL) for about 1 hour. The film is then suspended in 1 molar sodium chloride (220 mL) and the amount of sulfonation is determined by titration with 0.01 molar sodium hydroxide to a pH 7 end point. The amount of sulfonation (in meq/g SO3H) with reaction-time is 0.64 (1 hour), 1.27 (6.5 hours), 1.71 (16 hours), 1.86 (24 hours), 2.31 (48 hours), and 2.6 (60 hours). The sulfonated poly(phenylene sulfide) film can be used for antimicrobial applications as coating materials or as protective films for use with face shields.
Example 4: An antifog coating composition was prepared by adding the SSBC-1H or SSBC-1TP in a mixture of toluene/propanol (50:50) solvents to obtain a concentration of about 10-15%. PET substrates were coated with the antifog coating composition by using roll coating method and dried at room temperature in a dry box with nitrogen purge for the removal of solvents. The dried PET substrates containing the antifog coating layer with varying thicknesses were used for further testing. Table 1 shows details of samples and their antifog performance. Table 2 represents antifog performance measured as percentages of transmittance.
As used herein, the term “comprising” means including elements or steps that are identified following that term, but any such elements or steps are not exhaustive, and an embodiment can include other elements or steps. Although the terms “comprising” and “including” have been used herein to describe various aspects, the terms “consisting essentially of” and “consisting of” can be used in place of “comprising” and “including” to provide for more specific aspects of the disclosure and are also disclosed.
For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained. It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural references unless expressly and unequivocally limited to one referent. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.
Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed disclosure belongs. the recitation of a genus of elements, materials or other components, from which an individual component or mixture of components can be selected, is intended to include all possible sub-generic combinations of the listed components and mixtures thereof.
The patentable scope is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. To an extent not inconsistent herewith, all citations referred to herein are hereby incorporated by reference.
Claims
1. A face shield comprising:
- a transparent face panel configured to extend facing at least a portion of a face of a wearer, the transparent face panel comprising: a substrate having a first surface adapted to be disposed facing the face of the wearer and second surface disposed opposite to the first surface, and at least one of first surface and the second surface is protected by a sulfonated polymeric layer for killing at least 90% microbes within 120 minutes of contact with the transparent face panel; and wherein the sulfonated polymeric layer consists essentially of a sulfonated polymer, the sulfonated polymer from the group of perfluorosulfonic acid polymers, polystyrene sulfonates, sulfonated block copolymers, sulfonated polyolefins, sulfonated polyimides, sulfonated polyamides, sulfonated polyesters, sulfonated polysulfones, sulfonated polyketones, sulfonated poly(arylene ether), and mixtures thereof, the sulfonated polymer has a degree of sulfonation of >10%; wherein the sulfonated polymeric layer has a thickness of at least >1 μm.
2. The face shield of claim 1, wherein the sulfonated polymer has an ionic exchange capacity (IEC) of >0.5 meq/g.
3. The face shield of claim 1, wherein the sulfonated polymeric layer has a thickness of at least >5 μm to kill >95% of microbes within 120 minutes of contact after six months of protection.
4. The face shield of claim 1, wherein the sulfonated polymer has a degree of sulfonation of 10-100 mol %.
5. The face shield of claim 1, wherein the sulfonated polymer is a selectively sulfonated negative-charged anionic block copolymer having a general configuration of: A-B-A, (A-B)n(A), (A-B-A)n, (A-B-A)nX, (A-B)nX, A-D-B, A-B-D, A-D-B-D-A, A-B-D-B-A, (A-D-B)nA, (A-B-D)nA (A-D-B)nX, (A-B-D)nX or mixtures thereof, wherein
- n is an integer from 0 to 30,
- X is a coupling agent residue,
- each A and D block is a polymer block resistant to sulfonation,
- each B block is susceptible to sulfonation,
- the A block is selected from polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) alpha olefins of 3 to 18 carbon atoms; (iv) 1,3-cyclodiene monomers, (v) monomers of conjugated dienes having a vinyl content less than 35 mol percent prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) mixtures thereof;
- the B block is a vinyl aromatic monomer, and
- the D block is a hydrogenated polymer or copolymer of a conjugated diene selected from isoprene, 1,3-butadiene and mixtures thereof; and
- wherein the block B is selectively sulfonated to contain from 10-100 mol % sulfonic acid or sulfonate salt functional groups based on the number of monomer units, for the coating material to kill at least 99% of microbes within 30 minutes of contact.
6. The face shield of claim 1, wherein the sulfonated polymeric layer has a surface pH of <3.0.
7. The face shield of claim 1, wherein the sulfonated polymer is neutralized with at least a salt selected from ammonium, phosphonium, pyridinium, and sulfonium salts.
8. The face shield of claim 1, wherein the sulfonated polymeric layer is applied onto one of the first surface and the second surface by dip coating, spray coating, dispersion coating, solvent casting, or adhesively attached as a peel-and-stick film.
9. The face shield of claim 1, further comprising an attachment structure coupled to the face panel and configured to secure the face panel in front of the face of the wearer.
10. The face shield of claim 9, wherein the attachment structure is an elastic band attached to a first and second side edges of the face panel.
11. The face shield of claim 10, wherein the attachment structure includes
- a first strap attached to a first side edge of the face panel,
- a second strap attached to a second side edge of the face panel, and
- a coupler having a first member attached to the first strap and a second member attached to the second strap and adapted to removably engage with the first member to facilitate the engagement of the attachment structure with the wearer's head.
12. The face shield of claim 1, wherein the transparent face panel is removable.
13. The face shield of claim 9, wherein the attachment structure comprises any of: a cap adapted to be worn over the wearer's head with the face panel adapted to be removably engaged with the cap; an eyeglass frame removably engaged with the face panel; a hook-and-loop fastener assembly; and a protective garment to be worn by the wearer.
14. The face shield of claim 1, wherein the substrate forming the face panel comprises a material selected from the group of polyesters, polycarbonates, allyl diglycolcarbonates, polyacrylates, polystyrenes, cellulose acetate butyrate, glass, and combinations thereof, and wherein the substrate forming the face panel has a thickness ranging from 0.001 to 2 mm.
15. The face shield of claim 1, wherein the first surface facing the face of the wearer is protected by a sulfonated polymeric layer having a Tfog of >15 minutes.
16. An article comprising a substrate and a coating layer is provided on at least one surface of the substrate;
- wherein the coating layer comprises a sulfonated styrenic block copolymer obtained by sulfonation of a styrenic block copolymer;
- wherein the styrenic block copolymer comprises a polymer block A selected from polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) alpha olefins of 3 to 18 carbon atoms, (iv) 1,3-cyclodiene monomers, (v) monomers of conjugated dienes having a vinyl content less than 35 mole % prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) mixtures thereof; a polymer block B of a vinyl aromatic monomer; and a polymer block D of a conjugated diene monomer;
- wherein at least one polymer block A, B, or D is sulfonated to obtain a degree of sulfonation of the sulfonated styrenic block copolymer of greater than 10 mole %, based on total weight of the sulfonated styrenic block copolymer;
- wherein the article with the antifog coating layer has: a Tfog of greater than 8 seconds, measured at 40° C. steam test according to ANSI/ISEA Z87.1; and a yellowness index (ΔYI) of less than 4, according to ASTM E313; and
- wherein the coating layer has a thickness of at least >1 μm to kill at least 90% of microbes upon within 120 minutes of contact with the coating layer.
17. The article of claim 16, wherein the coating layer is prepared by mixing the sulfonated styrenic block copolymer and optional additives in an organic solvent for a total solid content of sulfonated styrenic block copolymer in the organic solvent in the range of 5 to 30 wt. %, based on total weight of the organic solvent.
18. The article of claim 17, wherein the organic solvent is selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, acetone, cyclohexanone, benzene, toluene, xylene, n-hexane, cyclohexane, n-heptane, n-octane, n-decane, and mixtures thereof.
19. The article of claim 16, wherein the coating layer has a thickness of 1 to 100 μm.
20. The article of claim 16, wherein the substrate is at least one selected from the group consisting of polycarbonate, acrylic, styrene, polyvinylchloride, polybisallyl carbonate, polyethylene terephthalate, bi-axially oriented polypropylene (BOPP), polyethylene naphthenate, triacetate, and cellulose acetate; wherein the substrate has a thickness of 10 μm to 10 mm.
Type: Application
Filed: Oct 17, 2022
Publication Date: Mar 16, 2023
Applicant: Kraton Polymers LLC (Houston, TX)
Inventors: Roger Tocchetto (Houston, TX), Bert Krutzer (Amsterdam)
Application Number: 18/047,123
