Polymer latex

Abstract

This invention relates to a polymer latex, a method for preparing the polymer latex, its use, an impregnation molding method, and articles obtained from the latex, the polymer latex comprising: (A) particles of a latex polymer (A), which is obtained by free radical emulsion polymerization of a mixture of olefinically unsaturated monomers, the latex polymer containing a plurality of functional groups (x); and (B) a compound having β-hydroxy ester bonds and at least one additional functional group (y) reactive to the functional group (x) on the latex polymer (A).

Description

[0001] This invention relates to polymer latex, methods for preparing such polymer latex, use of the polymer latex in the production of elastomer articles, use for coating or impregnating substrates, formulations of latex containing the polymer latex, methods for preparing elastomer articles, and articles prepared by using the polymer latex. Background Technology

[0002] In the field of manufacturing polymer latex-based articles, it is generally desirable to achieve high tensile strength and high elongation of the film forming the article to provide high mechanical strength and desired softness. This is particularly important for surgical gloves. Furthermore, there has been a recent increase in allergic reactions to latex-based products, such as natural rubber latex, which has historically been used in the manufacture of latex products like dip-molded products and contains up to 5% non-rubber components such as proteins, lipids, and trace elements. Users of natural rubber latex products have developed type I hypersensitivity reactions, caused by residual extractable latex proteins present in natural rubber products.

[0003] Sulfur vulcanization systems, which typically involve sulfur and sulfur-containing accelerators, are used to crosslink natural and synthetic polymer latexes. The use of these sulfur vulcanization systems in rubber glove manufacturing can cause delayed type IV hypersensitivity reactions, such as allergic contact dermatitis.

[0004] Therefore, several attempts have been made in the prior art to avoid sulfur vulcanization systems, in particular to provide polymer latexes that can be used to manufacture dip-molded articles without requiring standard sulfur vulcanization systems that include sulfur-containing accelerators previously used therein to obtain the desired mechanical properties of the final product.

[0005] US 7,345,111 relates to acrylic polymer emulsions and gloves formed from the emulsions. The polymer is formed by polymerizing a total of 100% by weight of a monomer mixture comprising 50% to 90% by weight of alkyl acrylates or alkyl methacrylates, 9% to 49% by weight of vinyl monomers having a glass transition temperature of not less than 80°C as homopolymers, 0.2% to 100% by weight of vinyl monomers having carboxyl groups, and 0.1% to 5% by weight of a crosslinkable monomer, which is a poly(tetramethylene ether) glycol diglycidyl ether with a molecular weight of not less than 280.

[0006] US 8,975,351 discloses a sulfur-free and vulcanization-accelerator-free latex composition for rubber gloves. The composition comprises a conjugated diene monomer, an olefinically unsaturated nitrile monomer, an olefinically unsaturated acid monomer, an olefinically unsaturated monomer copolymerizable with the olefinically unsaturated nitrile monomer and the olefinically unsaturated acid monomer, and a reactive compound containing two or more reactive groups. Examples of such compounds are polyether glycol diglycidyl ether.

[0007] Similarly, US 8,044,138 discloses a carboxylic acid-modified nitrile copolymer latex prepared from a conjugated diene monomer, an olefinically unsaturated nitrile monomer, an olefinically unsaturated acid monomer, and an unsaturated monomer having at least one crosslinkable functional group selected from vinyl or epoxy groups as constituent monomers. In the examples, glycidyl methacrylate is particularly used as a monomer having at least one crosslinkable functional group.

[0008] WO 2017 / 209596 discloses a polymer latex for dip molding applications comprising two different types of latex particles. One latex particle is carboxylated, while the second latex particle contains ethylene oxide functional groups. This latex composition provides numerous advantages for the final dip-molded product, such as achieving desired mechanical properties without sulfur vulcanization, improved solvent resistance required for industrial glove applications, and economical production of dip-molded articles in terms of reduced overall processing time and energy consumption. Furthermore, the inventors have discovered that, during crosslinking of the dip-molded article, the reaction between the carboxylic acid functional groups on the carboxylated latex and the ethylene oxide functional groups on the second latex produces β-hydroxy ester bonds, which provide self-healing properties to the resulting elastomer film, as described in co-pending application PCT / MY2019 / 000017.

[0009] Therefore, the object of the present invention is to provide a polymer latex composition that produces a softer film while retaining the advantageous properties of polymer latexes as described, for example, in WO 2017 / 209596.

[0010] Another objective is to provide a polymer latex composition that can be produced more economically while retaining the advantageous properties of polymer latexes, for example, as described in WO 2017 / 209596.

[0011] Another objective is to provide a polymer latex composition having an increased pot life while retaining, for example, the advantageous properties of polymer latexes described in WO 2017 / 209596. Invention Overview

[0013] Therefore, according to one aspect, the present invention relates to a polymer latex for preparing an elastomer film, comprising:

[0014] (A) Particles of a latex polymer (A), said latex polymer (A) being obtained by free radical emulsion polymerization of a mixture of olefinically unsaturated monomers, said latex polymer containing a plurality of functional groups (x); and

[0015] (B) A compound having a β-hydroxy ester bond and at least one additional functional group (y) that is reactive with the functional group (x) on the latex polymer (A).

[0016] According to another aspect, the present invention relates to a method for preparing a polymer latex, comprising:

[0017] (i) In an emulsion polymerization method, a mixture of olefinically unsaturated monomers for a latex polymer (A) is polymerized to obtain a latex, the mixture containing at least one monomer that, upon polymerization, results in a functional group (x), the latex comprising particles of the latex polymer (A) having a plurality of functional groups (x); and

[0018] (ii) Adding a compound (B) having a β-hydroxy ester bond and at least one additional functional group (y) that is reactive with the functional group (x) on the latex polymer (A).

[0019] The present invention also relates to the use of the above-mentioned polymer latex in the production of articles or for coating or impregnating substrates, preferably textile substrates.

[0020] The present invention also relates to a compounded latex composition suitable for producing articles, comprising a polymer latex as defined above and an auxiliary agent optionally selected from sulfur vulcanizing agents, sulfur vulcanizing accelerators, crosslinking agents, polyvalent cations and combinations thereof.

[0021] As described above, the polymer latex of the present invention can be successfully used without sulfur vulcanizing agents and sulfur vulcanization accelerators without compromising the desired mechanical properties. Therefore, it is preferable that the compounded latex compositions of the present invention are free of sulfur vulcanizing agents and sulfur vulcanization accelerators.

[0022] The present invention also relates to a method for preparing dip-molded articles, the method comprising:

[0023] a) Provides the compounded latex of the present invention;

[0024] b) Immerse the mold with the desired shape of the final product in a coagulant bath containing a metal salt solution;

[0025] c) Remove the mold from the coagulant bath and optionally dry the mold;

[0026] d) Immerse the mold treated in steps b) and c) into the compounded latex composition of step a);

[0027] e) Allow the latex film on the mold surface to solidify;

[0028] f) Remove the latex-coated mold from the compounded latex composition and optionally immerse the latex-coated mold in a water bath;

[0029] g) Optionally dry the latex-coated mold;

[0030] h) Heat-treating the latex-coated mold obtained from step e) or f) at a temperature of 40°C to 180°C and / or exposing the latex-coated mold obtained from step e) or f) to UV radiation; and

[0031] i) Remove the latex product from the mold.

[0032] The present invention also relates to articles prepared by using polymer latex or compounded latex compositions according to the present invention. Invention Details

[0034] This invention relates to a polymer latex comprising:

[0035] (A) Particles of a latex polymer (A), said latex polymer (A) being obtained by free radical emulsion polymerization of a mixture of olefinically unsaturated monomers, said latex polymer containing a plurality of functional groups (x); and

[0036] (B) A compound having a β-hydroxy ester bond and at least one additional functional group (y) that is reactive with the functional group (x) on the latex polymer (A).

[0037] Suitable functional groups (x) on the latex polymer (A) may be selected from groups having carbon-carbon double bonds, carboxylic acid functional groups, hydroxyl groups, epoxy groups, acetoacetyl groups, primary or secondary amino groups, acetoxy groups, isocyanate groups, alkoxysilyl groups, alkoxy groups, dioxane-pentanone functional groups, and combinations thereof.

[0038] Latex polymer (A) containing multiple functional groups (x):

[0039] The latex polymer (A) used according to the present invention can be prepared by any suitable free radical emulsion polymerization method known in the art. Suitable process parameters are those that will be discussed below.

[0040] The unsaturated monomers used to prepare the latex polymer (A) and their relative amounts are not particularly critical, as long as the monomer mixture contains at least one olefinically unsaturated monomer that provides multiple functional groups (x) on the latex polymer (A). Monomer compositions containing conjugated dienes and olefinically unsaturated nitrile compounds are particularly suitable for dip molding applications.

[0041] According to the present invention, the monomer composition for latex polymer (A) may comprise:

[0042] (a) 15 to 99% by weight of conjugated dienes;

[0043] (b) 1 to 80% by weight of monomers selected from olefinic unsaturated nitrile compounds;

[0044] (c) 0 to 10% by weight of olefinic unsaturated compounds with functional groups (x) other than conjugated dienes.

[0045] (d) 0 to 80% by weight of vinyl aromatic monomers; and

[0046] (e) 0 to 65% by weight of alkyl esters of olefinic unsaturated acids

[0047] The weight percentage is based on the total weight of the monomers in the monomer mixture.

[0048] The conjugated diene monomers suitable for preparing the latex polymer (A) according to the present invention include those selected from: 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-octadiene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-hexadiene, 2,3-diethyl-1,3-butadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, 3,7-dimethyl-1,3-butadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, 3,7-dimethyl-1,3-butadiene, 3 ... 6-Octatriene, 2-methyl-6-methylene-1,7-octatriene, 7-methyl-3-methylene-1,6-octatriene, 1,3,7-octatriene, 2-ethyl-1,3-butadiene, 2-pentyl-1,3-butadiene, 3,7-dimethyl-1,3,7-octatriene, 3,7-dimethyl-1,3,6-octatriene, 3,7,11-trimethyl-1,3,6,10-dodecanetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecanetraene, 2,6-dimethyl-2,4,6-octatriene, 2-phenyl-1,3-butadiene, and 2-methyl-3-isopropyl-1,3-butadiene and 1,3-cyclohexadiene. 1,3-Butadiene, isoprene, and combinations thereof are preferred conjugated dienes. 1,3-Butadiene is the most preferred diene. Typically, based on the total weight of the monomers, the amount of the conjugated diene monomer ranges from 15 wt% to 99 wt%, preferably 20 wt% to 99 wt%, more preferably 30 wt% to 75 wt%, and most preferably 40 wt% to 70 wt%. Therefore, based on the total weight of the olefinically unsaturated monomers used in the latex polymer (A), the conjugated diene can be present in amounts of at least 15 wt%, at least 20 wt%, at least 22 wt%, at least 24 wt%, at least 26 wt%, at least 28 wt%, at least 30 wt%, at least 32 wt%, at least 34 wt%, at least 36 wt%, at least 38 wt%, or at least 40 wt%.

[0049] Therefore, the conjugated diene monomer can be used in amounts not exceeding 95 wt%, not exceeding 90 wt%, not exceeding 85 wt%, not exceeding 80 wt%, not exceeding 78 wt%, not exceeding 76 wt%, not exceeding 74 wt%, not exceeding 72 wt%, not exceeding 70 wt%, not exceeding 68 wt%, not exceeding 66 wt%, not exceeding 64 wt%, not exceeding 62 wt%, not exceeding 60 wt%, not exceeding 58 wt%, or not exceeding 56 wt%. Those skilled in the art will understand that any range between any explicitly disclosed lower and upper limits is disclosed herein.

[0050] The unsaturated nitrile monomers that can be used in this invention include polymerizable unsaturated aliphatic nitrile monomers containing 2-4 straight-chain or branched carbon atoms, which may be substituted with acetyl or other nitrile groups. Such nitrile monomers include acrylonitrile, methacrylonitrile, α-cyanoethyl acrylonitrile, fumaric acid, and combinations thereof, with acrylonitrile being the most preferred. Based on the total weight of the olefinically unsaturated monomers used in the latex polymer (A), the content of these nitrile monomers can be from 1 to 80% by weight, preferably 10 to 70% by weight, or 1 to 60% by weight, and more preferably 15 to 50% by weight, even more preferably 20 to 50% by weight, and most preferably 23 to 43% by weight.

[0051] Therefore, based on the total weight of the olefinic unsaturated monomers used in the latex polymer (a), the unsaturated nitriles may be present in amounts of at least 1 wt%, 5 wt%, at least 10 wt%, at least 12 wt%, at least 14 wt%, at least 16 wt%, at least 18 wt%, at least 20 wt%, at least 22 wt%, at least 24 wt%, at least 26 wt%, at least 28 wt%, at least 30 wt%, at least 32 wt%, at least 34 wt%, at least 36 wt%, at least 38 wt%, or at least 40 wt%.

[0052] Therefore, unsaturated nitrile monomers may be used in amounts not exceeding 80 wt%, not exceeding 75 wt%, not exceeding 73 wt%, not exceeding 70 wt%, not exceeding 68 wt%, not exceeding 66 wt%, not exceeding 64 wt%, not exceeding 62 wt%, not exceeding 60 wt%, not exceeding 58 wt%, not exceeding 56 wt%, not exceeding 54 wt%, not exceeding 52 wt%, not exceeding 50 wt%, not exceeding 48 wt%, not exceeding 46 wt%, or not exceeding 44 wt%. Those skilled in the art will understand that any range between any explicitly disclosed lower and upper limits is disclosed herein.

[0053] In the monomer composition for preparing latex polymer (A) of the present invention, the olefinic unsaturated compound having a functional group (x) different from that of the conjugated diene can be selected from...

[0054] (c1) An olefinic unsaturated compound having at least two different olefinic unsaturated groups;

[0055] (c2) Alkenyl unsaturated acids and their salts;

[0056] (C3) Hydroxyl-functional olefinic unsaturated compounds;

[0057] (c4) Ethylene oxide-functionalized olefinic unsaturated compounds;

[0058] (c5) Acetylacetyl functional olefinic unsaturated compounds;

[0059] (c6) An alkene-bonded unsaturated compound containing a primary or secondary amino group.

[0060] (c7) Acetoxyl-functional alkene unsaturated compounds;

[0061] (c8) Isocyanate-functionalized alkene-bonded unsaturated compounds;

[0062] (c9) Alkoxysilyl-functionalized alkene-bonded unsaturated compounds;

[0063] (C10) Alkoxy-functionalized alkene unsaturated compounds;

[0064] (c11) Dioxacyclopentanone-functional olefinic unsaturated compounds;

[0065] and their combinations;

[0066] Suitable olefinically unsaturated compounds (c1) having at least two different olefinically unsaturated groups may be selected from allyl (meth)acrylate and vinyl (meth)acrylate.

[0067] Suitable olefinically unsaturated acids (C2) and their salts can be selected from olefinically unsaturated carboxylic acid monomers, olefinically unsaturated sulfonic acid monomers, and olefinically unsaturated phosphorus-containing acid monomers. Suitable olefinically unsaturated carboxylic acid monomers include monocarboxylic acid and dicarboxylic acid monomers, monoesters of dicarboxylic acids, and carboxyl esters of olefinically unsaturated acids, such as 2-carboxyethyl (meth)acrylate. In carrying out the invention, it is preferred to use olefinically unsaturated aliphatic mono- or dicarboxylic acids or anhydrides containing 3 to 5 carbon atoms. Examples of monocarboxylic acid monomers include acrylic acid, methacrylic acid, and crotonic acid, and examples of dicarboxylic acid monomers include fumaric acid, itaconic acid, maleic acid, and maleic anhydride. Other suitable examples of olefinically unsaturated acids include vinylacetic acid, vinyl lactic acid, vinyl sulfonic acid, 2-methyl-2-propen-1-sulfonic acid, styrene sulfonic acid, acrylamidomethylpropanesulfonic acid, and their salts. Particularly preferred are (meth)acrylate, crotonic acid, itaconic acid, maleic acid, fumaric acid, and combinations thereof.

[0068] Examples of olefinically bonded unsaturated sulfonic acid monomers: vinyl sulfonic acid, phenyl vinyl sulfonate, sodium 4-vinylbenzene sulfonate, 2-methyl-2-propen-1-sulfonic acid, 4-styrene sulfonic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid and their salts.

[0069] Examples of olefinically unsaturated phosphorus-containing acid monomers: vinylphosphonic acid, dimethyl vinylphosphonate, diethyl vinylphosphonate, diethyl allylphosphonate, allylphosphonic acid and their salts.

[0070] Suitable hydroxyl-functionalized olefinic unsaturated compounds (C3) can be selected from N-hydroxymethylacrylamide and hydroxyalkyl esters of olefinic unsaturated acids.

[0071] The (meth)acrylate hydroxyalkyl ester monomers that can be used to prepare the polymer latex according to the present invention include hydroxyalkyl acrylate and hydroxyalkyl methacrylate monomers based on ethylene oxide, propylene oxide, and higher epoxides or mixtures thereof. Examples are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl acrylate. Preferably, the (meth)acrylate hydroxyalkyl ester monomer is 2-hydroxyethyl (meth)acrylate.

[0072] Suitable ethylene oxide-functionalized olefinically unsaturated monomers (C4) can be selected from glycidyl (meth)acrylate, allyl glycidyl ether, vinyl glycidyl ether, vinylcyclohexene oxide, limonene oxide, 2-ethyl glycidyl acrylate, 2-ethyl glycidyl methacrylate, 2-(n-propyl) glycidyl acrylate, 2-(n-propyl) glycidyl methacrylate, 2-(n-butyl) glycidyl acrylate, 2-(n-butyl) glycidyl methacrylate, glycidyl methacrylate methyl ester, glycidyl acrylate, (3′,4′-epoxyheptyl)-2-ethyl acrylate, (3 (6′,7′-epoxyheptyl)-2-ethyl methacrylate, (6′,7′-epoxyheptyl)acrylate, (6′,7′-epoxyheptyl)methacrylate, allyl-3,4-epoxyheptyl ether, 6,7-epoxyheptyl allyl ether, vinyl-3,4-epoxyheptyl ether, 3,4-epoxyheptyl vinyl ether, 6,7-epoxyheptyl vinyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3-vinylcyclohexene oxide, α-methyl glycidyl methacrylate, 3,4-epoxycyclohexyl meth(meth)acrylate, and combinations thereof. Glycidyl (meth)acrylate is particularly preferred.

[0073] Suitable acetoacetyl-functionalized olefinic unsaturated compounds (C5) can be selected from acetoacetoxyethyl methacrylate, acetoacetoxypropyl methacrylate, allyl acetoacetate, acetoacetoxybutyl methacrylate, 2,3-di(acetoacetoxy)propyl methacrylate, (2-acetoacetamino-2-methylpropyl) methacrylate, 3-(methacryloyloxy)-2,2-dimethylpropyl 3-oxobutyrate, 3-(methacryloyloxy)-2,2,4,4-tetramethylcyclobutyl 3-oxobutyrate, 1-((methacryloyloxy)-2,2,4-trimethylpent-3-yl 3-oxobutyrate, and (4-((methacryloyloxymethyl)cyclohexyl)methyl 3-oxobutyrate.

[0074] Suitable olefinic unsaturated compounds (C6) with primary or secondary amino groups can be selected from (meth)acrylamide, alkyl (meth)acrylamide, such as N-ethyl (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-phenyl (meth)acrylamide, N-(isobutoxymethyl)(meth)acrylamide, N-propyl (meth)acrylamide, aminoalkyl esters of olefinic unsaturated acids, such as 2-aminoethyl (meth)acrylate, N-(3-aminopropyl)(meth)acrylamide hydrochloride, 2-aminoethyl (meth)acrylamide hydrochloride, (meth)acrylate (2-(N-tert-butoxycarbonylamino)ethyl ester and N-3-(dimethylamino)propyl (meth)acrylamide).

[0075] Suitable acetoxy-functionalized olefinic unsaturated compounds (C7) can be selected from diacetone acrylamide.

[0076] Suitable isocyanate-functionalized olefinic unsaturated compounds (C8) can be selected from ethyl 2-isocyanate (meth)acrylate, allyl isocyanate, vinyl isocyanate, and 3-isopropenyl-α,α-dimethylbenzyl isocyanate.

[0077] Suitable alkoxysilyl-functionalized olefinic unsaturated compounds (c9) may be selected from vinyltrimethoxysilane, vinyltriethoxysilane and 3-methacryloyloxypropyltrimethoxysilane;

[0078] Suitable alkoxy-functionalized olefinic unsaturated compounds (C10) may be selected from N-methoxymethyl-(meth)acrylamide, N-n-butoxy-methyl-(meth)acrylamide, N-isobutoxy-methyl-(meth)acrylamide, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, and methoxyethoxyethyl acrylate. Preferred alkoxy-functionalized olefinic unsaturated compounds are ethoxyethyl acrylate and methoxyethyl acrylate.

[0079] Suitable dioxolane-functionalized olefinic unsaturated compounds (C11) may be selected from glycerol carbonate (meth) acrylate and 4-vinyl-1,3-dioxolane-2-one (vinyl ethylene carbonate).

[0080] Monomer c) provides functional groups (x) that are reactive to functional groups (y) on the compound (B) according to the invention. Furthermore, due to their polarity, they may affect the properties of the polymer dispersion. The type and amount of these monomers are thus determined. Based on the total weight of the olefinically unsaturated monomers used in the latex polymer (a), this amount is typically 0.05 to 10 wt%, particularly 0.1 to 10 wt% or 0.5 to 7 wt%, preferably 0.1 to 9 wt%, more preferably 0.1 to 8 wt%, even more preferably 1 to 7 wt%, and most preferably 2 to 7 wt%. Therefore, the olefinic unsaturated acid compound (c) may be present in amounts of at least 0.01 wt%, at least 0.05 wt%, at least 0.1 wt%, at least 0.3 wt%, at least 0.5 wt%, at least 0.7 wt%, at least 0.9 wt%, at least 1 wt%, at least 1.2 wt%, at least 1.4 wt%, at least 1.6 wt%, at least 1.8 wt%, at least 2 wt%, at least 2.5 wt%, or at least 3 wt%. Similarly, based on the total weight of the olefinic unsaturated monomers used in the latex polymer (A), the olefinic unsaturated compound (c) may be present in amounts of no more than 10 wt%, no more than 9.5 wt%, no more than 9 wt%, no more than 8.5 wt%, no more than 8 wt%, no more than 7.5 wt%, no more than 7 wt%, no more than 6.5 wt%, no more than 6 wt%, no more than 5.5 wt%, or no more than 5 wt%. Those skilled in the art will understand that this document discloses any scope defined by a clearly defined lower limit and a clearly defined upper limit.

[0081] Representative vinyl aromatic monomers include, for example, styrene, α-methylstyrene, vinyltoluene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene, vinylnaphthalene, vinyltoluene and vinylxylene, 2-vinylpyridine, 4-vinylpyridine and 1,1-diphenylethylene and substituted 1,1-diphenylethylene, 1,2-diphenylethylene and substituted 1,2-diphenylethylene. Mixtures of one or more vinyl aromatic compounds may also be used. Preferred monomers are styrene and α-methylstyrene. Based on the total weight of the olefinically unsaturated monomers used in the latex polymer (A), the amount of vinyl aromatic compound can range from 0 to 80% by weight, or 0 to 70% by weight, or 0 to 50% by weight, preferably 0 to 40% by weight, more preferably 0 to 25% by weight, even more preferably 0 to 15% by weight, and most preferably 0 to 10% by weight. Therefore, based on the total weight of the olefinically unsaturated monomers used in the latex polymer (A), the vinyl aromatic compound can be present in amounts not exceeding 80% by weight, not exceeding 75% by weight, not exceeding 60% by weight, not exceeding 50% by weight, not exceeding 40% by weight, 35% by weight, not exceeding 30% by weight, not exceeding 25% by weight, not exceeding 20% ​​by weight, not exceeding 18% by weight, not exceeding 16% by weight, not exceeding 14% by weight, not exceeding 12% by weight, not exceeding 10% by weight, not exceeding 8% by weight, not exceeding 6% by weight, not exceeding 4% by weight, not exceeding 2% by weight, or not exceeding 1% by weight. The vinyl aromatic compound may also be completely absent.

[0082] Suitable alkyl esters of olefinic unsaturated acids to be used according to the present invention include n-alkyl, isoalkyl, or tertiary alkyl esters of (meth)acrylic acid, wherein the alkyl group has 1 to 20 carbon atoms, and reaction products of methacrylic acid with glycidyl esters of new acids such as tertiary carbonate, neodecanoic acid, or neopentanoic acid.

[0083] Typically, the preferred alkyl esters of (meth)acrylic acid can be selected from (meth)acrylic acid C1-C2. 10Alkyl esters, preferably C1-C8 alkyl esters of (meth)acrylate. Examples of such acrylate monomers include n-butyl acrylate, sec-butyl acrylate, ethyl acrylate, hexyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, 4-methyl-2-pentyl acrylate, 2-methylbutyl acrylate, methyl methacrylate, butyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hexyl acrylate, cyclohexyl methacrylate, and cetyl methacrylate. Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and combinations thereof are preferred.

[0084] Based on the total weight of the olefinically unsaturated monomers used in the latex polymer (A), the alkyl esters of the olefinically unsaturated acid may typically be present in amounts not exceeding 65 wt%, not exceeding 60 wt%, not exceeding 55 wt%, not exceeding 50 wt%, not exceeding 45 wt%, not exceeding 40 wt%, not exceeding 35 wt%, not exceeding 30 wt%, not exceeding 25 wt%, not exceeding 20 wt%, not exceeding 18 wt%, not exceeding 16 wt%, not exceeding 14 wt%, not exceeding 12 wt%, not exceeding 10 wt%, not exceeding 8 wt%, not exceeding 6 wt%, not exceeding 4 wt%, not exceeding 2 wt%, or not exceeding 1 wt%.

[0085] Furthermore, the mixture of olefinically unsaturated monomers for latex polymer (A) of the present invention may contain additional olefinically unsaturated monomers different from the monomers described above. These monomers may be selected from vinyl esters and monomers having two identical olefinically unsaturated groups.

[0086] Vinyl ester monomers that can be used according to the present invention include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl 2-ethylhexanoate, vinyl stearate, and vinyl tert-carbonate. The most preferred vinyl ester monomer for use in the present invention is vinyl acetate. Based on the total weight of the olefinically unsaturated monomers used in the latex polymer (a), the vinyl ester monomers can generally be present in amounts not exceeding 18 wt%, not exceeding 16 wt%, not exceeding 14 wt%, not exceeding 12 wt%, not exceeding 10 wt%, not exceeding 8 wt%, not exceeding 6 wt%, not exceeding 4 wt%, not exceeding 2 wt%, or not exceeding 1 wt%. Furthermore, based on the total weight of the olefinically unsaturated monomers, monomers having at least two identical olefinically unsaturated groups can be present in the monomer mixture used to prepare the polymer latex of the present invention in amounts from 0 to 6.0 wt%, preferably from 0.1 to 3.5 wt%. Based on the total weight of the olefinically unsaturated monomers, these monomers can generally be present in amounts not exceeding 6 wt%, not exceeding 4 wt%, not exceeding 2 wt%, or not exceeding 1 wt%. Suitable bifunctional monomers (referred to herein as multifunctional monomers) capable of providing internal crosslinking and branching in polymers can be selected from divinylbenzene and diacrylates and di(meth)acrylates. Examples of di(meth)acrylates are ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate. Monomers having at least two olefinically unsaturated groups are preferably selected from divinylbenzene, 1,2-ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate.

[0087] According to the present invention, the total amount of the monomers used to prepare the latex polymer (A) can be 100% by weight.

[0088] The mixture of olefinic unsaturated monomers for use in latex polymer (A) may contain:

[0089] - 20 to 99% by weight of conjugated diene, preferably selected from butadiene, isoprene and combinations thereof, more preferably butadiene;

[0090] -From 1 to 60% by weight of monomers selected from olefinic unsaturated nitrile compounds, preferably acrylonitrile;

[0091] - From 0 to 70% by weight of vinyl aromatic monomers, preferably styrene;

[0092] -C1-C8 alkyl esters of (meth)acrylate from 0 to 25% by weight;

[0093] - From 0.05 to 7% by weight of an olefinic unsaturated acid, preferably (meth)acrylic acid;

[0094] -Vinyl esters from 0 to 10% by weight:

[0095] The weight percentage is based on the total number of monomers present in the mixture.

[0096] The method for preparing the polymer latex of the present invention:

[0097] The latex polymer (A) according to the invention can be prepared by any emulsion polymerization method known to those skilled in the art, provided that a monomer mixture as defined herein is used. Particularly suitable are methods as described in EP-A 792 891.

[0098] Seed latex can be used in the emulsion polymerization used to prepare the latex polymer (A) of the present invention. Any seed particles known to those skilled in the art can be used.

[0099] The seed latex particles are preferably present in an amount of 0.01 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on the total olefinic unsaturated monomers used in 100 parts by weight of the polymer latex, including those used to prepare the seed particles, such as ethylene oxide functionalized latex particles (b). The lower limit of the amount of seed latex particles can therefore be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or 2.5 parts by weight. The upper limit of this dosage may be 10, 9, 8, 7, 6, 5.5, 5, 4.5, 4, 3.8, 3.6, 3.4, 3.3, 3.2, 3.1, or 3 parts by weight. Those skilled in the art will understand that any range formed by any explicitly disclosed lower and upper limits is expressly covered in this specification.

[0100] The method for preparing the above-mentioned polymer latex can be carried out at temperatures ranging from 0 to 130°C, preferably from 0 to 100°C, particularly preferably from 5 to 70°C, and very particularly preferably from 5 to 60°C, in the absence of an emulsifier or in the presence of one or more emulsifiers, and in the absence of a colloid and an initiator or in the presence of one or more colloids and one or more initiators. Temperatures include all values ​​and sub-values ​​therebetween, particularly including 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, and 125°C.

[0101] Initiators that can be used in carrying out this invention include water-soluble and / or oil-soluble initiators that are effective for polymerization purposes. Representative initiators are well known in the art and include, for example, azo compounds (e.g., AIBN, AMBN, and cyanopentanoic acid) and inorganic peroxide compounds, such as sodium, potassium, and ammonium salts of hydrogen peroxide, persulfate, peroxycarbonic acid, and peroxyboronic acid, as well as organic peroxide compounds, such as alkyl hydroperoxides, dialkyl peroxides, acyl hydroperoxides, and diacyl peroxides, and esters, such as tert-butyl perbenzoate, and combinations of inorganic and organic initiators.

[0102] The initiator is used in an amount sufficient to initiate the polymerization reaction at the desired rate. Typically, an initiator amount of 0.01 to 5 wt%, preferably 0.1 to 4 wt%, is sufficient based on the total weight of the polymer. The most preferred amount of initiator based on the total weight of the polymer is 0.01 to 2 wt%. The amount of initiator includes all values ​​and sub-values ​​within this range, particularly 0.01 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 4 wt%, and 4.5 wt%, based on the total weight of the polymer.

[0103] As is well known in the art, the aforementioned inorganic and organic peroxide compounds can be used alone or in combination with one or more suitable reducing agents. Examples of such reducing agents include sulfur dioxide, alkali metal metabisulfites, alkali metal bisulfites and ammonium bisulfites, thiosulfates, dithionites and formaldehyde hyposulfites, as well as hydroxylamine hydrochloride, hydrazine sulfate, ferric(II) sulfate, cuprous naphthate, glucose, sulfonic acid compounds such as sodium methanesulfonate, amine compounds such as dimethylaniline and ascorbic acid. The amount of reducing agent, relative to each part by weight of polymerization initiator, is preferably 0.03 to 10 parts by weight.

[0104] Surfactants or emulsifiers suitable for stabilizing latex particles include those conventional surfactants used in polymerization methods. One or more surfactants can be added to the aqueous and / or monomeric phases. In seeded methods, the effective amount of surfactant is selected to support the stabilization of particles as colloids, minimize inter-particle contact, and prevent agglomeration. In non-gelatinized methods, the effective amount of surfactant is selected to influence particle size.

[0105] Representative surfactants include saturated and olefinically unsaturated sulfonic acids or their salts, including, for example, unsaturated hydrocarbon sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, and methyl allyl sulfonic acid and their salts; aromatic hydrocarbon acids such as p-styrene sulfonic acid, isopropenylbenzene sulfonic acid, and ethyleneoxybenzene sulfonic acid and their salts; sulfoalkyl esters of acrylic acid and methacrylic acid, such as sulfoethyl methacrylate and sulfopropyl methacrylate and their salts, and 2-acrylamido-2-methylpropanesulfonic acid and their salts; alkylated diphenyl ether disulfonates, sodium dodecylbenzene sulfonate and sodium sulfosuccinate dihexyl esters, sodium alkyl esters of sulfonic acids, ethoxylated alkylphenols and ethoxylated alcohols; and fatty alcohol (poly)ether sulfates.

[0106] The type and amount of surfactant are typically determined by the number of particles, their size, and their composition. Based on the total weight of the monomers, the amount of surfactant is typically from 0 wt% to 20 wt%, preferably from 0 wt% to 10 wt%, more preferably from 0 wt% to 5 wt%. Based on the total weight of the monomers, the amount of surfactant includes all values ​​and sub-values ​​in between, particularly including 0 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, and 19 wt%. According to one embodiment of the invention, polymerization is carried out without the use of surfactant.

[0107] Various protective colloids can be used in place of the surfactants mentioned above, or in addition to the surfactants mentioned above. Suitable colloids include polyhydroxy compounds, such as partially acetylated polyvinyl alcohol, casein, hydroxyethyl starch, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polysaccharides and degraded polysaccharides, polyethylene glycol, and gum arabic. Preferred protective colloids are carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. Based on the total weight of the monomers, these protective colloids are typically used in amounts of 0 to 10 parts by weight, preferably 0 to 5 parts by weight, more preferably 0 to 2 parts by weight. The amount of protective colloid used includes all values ​​and sub-values ​​therebetween, particularly including 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, and 9% by weight, based on the total weight of the monomers.

[0108] Those skilled in the art will understand that the type and amount of monomers, surfactants, and protective colloids with polar functional groups are selected to make the polymer latex according to the invention suitable for dip molding applications. Therefore, it is preferred that the polymer latex composition of the invention has a maximum electrolyte stability of less than 30 mmol / L CaCl2 as determined in the form of critical coagulation concentration, preferably less than 25 mmol / L, more preferably less than 20 mmol / L, and most preferably less than 10 mmol / L (determined for the total solids content of 0.1% of the composition at pH 10 and 23°C).

[0109] If the electrolyte stability is too high, it will be difficult for the polymer latex to coagulate during the dip molding process, resulting in the absence of a continuous polymer latex film on the dipped mold or uneven thickness of the product.

[0110] Appropriately adjusting the electrolyte stability of polymer latex is within the general understanding of those skilled in the art. Electrolyte stability will depend on several factors, such as the amount and selection of monomers (especially those containing polar functional groups) used to prepare the polymer latex, and the selection and amount of the stabilizing system, such as the emulsion polymerization method used to prepare the polymer latex. The stabilizing system may contain surfactants and / or protective colloids.

[0111] Those skilled in the art can adjust the stabilizing system according to the selected monomers and their relative amounts used to prepare the polymer latex of the present invention to achieve the electrolyte stability according to the present invention.

[0112] Because there are many different effects on electrolyte stability, it is best to adjust it through trial and error. However, this can be easily accomplished without any inappropriate effort using the electrolyte stability testing methods disclosed above.

[0113] It is generally recommended to conduct emulsion polymerization in the presence of additional buffers and chelating agents. Suitable substances are, for example, alkali metal phosphates and pyrophosphates (buffers) and alkali metal salts of ethylenediaminetetraacetic acid (EDTA) or hydroxy-2-ethylenediaminetriacetic acid (HEEDTA) as chelating agents. The amounts of buffers and chelating agents are typically 0.001 to 1.0% by weight, based on the total amount of monomers.

[0114] Furthermore, the use of chain transfer agents (regulators) in emulsion polymerization can be advantageous. Typical agents are, for example, organosulfur compounds such as thioesters, 2-mercaptoethanol, 3-mercaptopropionic acid, and C1-C12-sulfur compounds. 12 Alkyl mercaptan, preferably n-dodecyl mercaptan and tert-dodecyl mercaptan. If present, the amount of chain transfer agent is typically 0.05 to 3.0% by weight, preferably 0.2 to 2.0% by weight, based on the total weight of the monomers used.

[0115] Furthermore, introducing partial neutralization into the polymerization process may be beneficial. Those skilled in the art will understand that the necessary control can be achieved by appropriately selecting this parameter.

[0116] Various other additives and ingredients can be added to prepare the latex compositions of the present invention. Such additives include, for example, defoamers, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, fluorescent whitening agents, crosslinking agents, accelerators, antioxidants, biocides, and metal chelating agents. Known defoamers include silicone oil and acetylenic glycol. Conventionally known wetting agents include alkylphenol ethoxylates, alkali metal dialkyl sulfosuccinates, acetylenic glycol, and alkali metal alkyl sulfates. Typical thickeners include polyacrylates, polyacrylamide, xanthan gum, modified cellulose, or particulate thickeners such as silica and clay. Typical plasticizers include mineral oil, liquid polybutene, liquid polyacrylates, and lanolin. Zinc oxide is a suitable crosslinking agent. Titanium dioxide (TiO2), calcium carbonate, and clay are commonly used fillers. Known accelerators and co-accelerators include dithiocarbamates such as zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dibenzyldithiocarbamate, zinc pentamethylenedithiocarbamate (ZPD), xanthates, thiurams such as tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), bispentamethylenethiuram hexasulfide (DPTT), and amines such as diphenylguanidine (DPG), di-o-tolylguanidine (DOTG), and o-tolyl biguanide (OTBG).

[0117] Compound (B)

[0118] According to the present invention, any compound comprising a β-hydroxy ester bond and at least one additional functional group (y) reactive to the functional group (x) on the latex polymer (A) can be used. Depending on the type of functional group (x) on the latex polymer (A), the functional group (y) can be selected from carbon-carbon double bonds, epoxy groups, thiols, hydroxyl groups, primary or secondary amino groups, isocyanates, oxazolinyl groups, aziridinyl groups, imino groups, carbodiimides, diol groups, ester groups, acetoxy groups, carboxylic acid groups, alkoxysilyl groups, dioxane-pentanone groups, acylhydrazide groups, and combinations thereof.

[0119] Functional group (y) provides the ability to crosslink with functional groups (x) on the latex polymer (A) to ensure that the elastomeric film of the final impregnated molded article exhibits the desired mechanical properties even without the use of sulfur vulcanization. Preferably, compound (B) contains multiple, such as two or three, preferably two functional groups (y). However, it is sufficient for compound (B) to contain only one functional group (x) because β-hydroxy ester bonds can also react with functional groups such as hydroxyl or alkoxy groups on the latex polymer chain during transesterification to provide crosslinking. The terminal position of functional group (y) in compound (B) is particularly suitable but not required.

[0120] β-hydroxy ester bonds can be reversibly opened and reformed, thereby providing the self-healing properties and recyclability of the elastomer films formed from the polymer latex of the present invention, as illustrated in the co-pending application PCT / MY2019 / 000017. This is also the case if compound (B) has only one functional group (y) and the β-hydroxy ester bond participates in the crosslinking reaction via transesterification. Then, thermally unstable β-hydroxy ester bonds remain in the ultimately crosslinked film.

[0121] The functional groups (x) on the latex polymer (A) and the functional groups (y) on the compound (B) can be selected to provide the following combinations:

[0122] - The functional group (x) is selected from groups having carbon-carbon double bonds, and the functional group (y) is selected from groups having carbon-carbon double bonds and thiols; or

[0123] - The functional group (x) is selected from carboxylic acid functional groups, and the functional group (y) is selected from epoxy, thiol, hydroxyl, primary or secondary amino, isocyanate, oxazolinyl, aziridinyl, imino, carbodiimide, diol, ester, and acetoxy; or

[0124] - The functional group (x) is selected from hydroxyl, and the functional group (y) is selected from alkoxysilyl, carboxylic acid; isocyanate, primary or secondary amino and ester group; or

[0125] - The functional group (x) is selected from epoxy groups, and the functional group (y) is selected from carboxylic acid functional groups, hydroxyl groups, and ester groups; or

[0126] - The functional group (x) is selected from acetoacetyl, and the functional group (y) is selected from groups having carbon-carbon double bonds, isocyanates, and primary or secondary amino groups; or

[0127] - The functional group (x) is selected from primary or secondary amino groups, and the functional group (y) is selected from carboxylic acid functional groups, epoxy groups, ester groups, and dioxane-pentanone groups; or

[0128] - The functional group (x) is selected from acetoxy, and the functional group (y) is selected from hydrazide and primary or secondary amino groups; or

[0129] - The functional group (x) is selected from isocyanate groups, and the functional group (y) is selected from carboxylic acid groups, hydroxyl groups, primary or secondary amino groups, and thiols; or

[0130] - The functional group (x) is selected from alkoxysilyl groups, and the functional group (y) is selected from hydroxyl and alkoxysilyl groups; or

[0131] - The functional group (x) is selected from alkoxy groups, and the functional group (y) is selected from ester groups; or

[0132] - The functional group (x) is selected from an ester group, and the functional group (y) is selected from a hydroxyl group, a carboxylic acid group, and an ester group; or

[0133] - The functional group (x) is selected from the dioxane pentanone group, and the functional group (y) is selected from the primary amino or secondary amino group.

[0134] Preferably, compound (B) is selected from glycerol dimethacrylate (GDMA), glycerol 1,3-diglyceride diacrylate (GDGDA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate, bisphenol A glyceride diacrylate, acetylpropionic acid methacrylate (KEMA), glycerol monomethacrylate, fatty acid modified glycidyl methacrylate, bisphenol A glycerolate diacrylate, (meth)acrylate 2-hydroxy-3-phenoxypropyl, eugenyl-2-hydroxypropyl methacrylate, and combinations thereof.

[0135] The polymer latex of the present invention may contain 80 to 99.9% by weight, preferably 85 to 99.9% by weight, more preferably 90 to 99.5% by weight, even more preferably 92 to 99.5% by weight, and most preferably 95 to 99.2% by weight of latex polymer (A) particles, and 0.1 to 20% by weight, preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, even more preferably 0.5 to 8% by weight, and most preferably 0.8 to 5% by weight of compound (B), based on the total weight of latex polymer (A) and compound (B). Therefore, the lower limit of the amount of latex polymer (a) particles may be 80% by weight, or 82% by weight, or 84% by weight, or 86% by weight, or 88% by weight, or 90% by weight, based on the total weight of latex particles in the composition. Based on the total weight of latex polymer (A) and compound (B), the upper limit of the amount of latex polymer (A) particles can be 99.9% by weight, or 99.5% by weight, or 99% by weight, or 98% by weight, or 97% by weight, or 96% by weight, or 95% by weight, or 94% by weight, or 93% by weight, or 92% by weight. Based on the total weight of latex particles in the composition, the lower limit of the amount of compound (B) can be 0.1% by weight, or 0.2% by weight, or 0.3% by weight, or 0.4% by weight, or 0.5% by weight, or 0.6% by weight, or 0.8% by weight, or 1% by weight, or 1.5% by weight, or 2% by weight, or 2.5% by weight, or 3% by weight. Based on the total weight of latex polymer (A) and compound (B), the upper limit of the amount of compound (B) can be 20% by weight, or 18% by weight, or 16% by weight, or 14% by weight, or 12% by weight, or 10% by weight, or 9% by weight, or 8% by weight, or 5% by weight. Those skilled in the art will understand that any range formed by any explicitly disclosed lower and upper limits is expressly disclosed in this specification.

[0136] According to the present invention, a latex polymer (A) is prepared by aqueous emulsion polymerization as described above. Compound (B) is added to the obtained polymer latex containing particles of latex polymer (A) at any suitable stage before forming an article, for example, comprising an elastomer film, from the polymer latex of the present invention. For example, compound (B) can be added to the polymer latex containing latex polymer (A) before or after compounding into an impregnation molding composition. If compound (B) is inert to the emulsion polymerization conditions for preparing latex polymer (A), a monomer mixture for latex polymer (A) can also be polymerized in the presence of compound (B). Compared to WO 2017 / 209596, the present invention has economic advantages, namely, that only one type of latex needs to be produced, and that many suitable compounds (B) are commercially available and can be added to the composition in any convenient manner.

[0137] Formulated latex compositions for the production of dip-molded articles:

[0138] The polymer latex of the present invention is particularly suitable for dip molding. Therefore, according to one aspect of the invention, polymer latexes are compounded to produce curable polymer latex compound compositions that can be directly used in dip molding processes. To obtain reproducible and good physical film properties, it is recommended to adjust the pH of the compounded polymer latex composition to a pH range of 7 to 11, preferably 8 to 10, more preferably 9 to 10, using a pH adjuster for dip molding to produce thin disposable gloves. To produce unloaded and / or loaded reusable gloves, it is recommended to adjust the pH of the compounded polymer latex composition to a pH range of 8 to 10, preferably 8.5 to 9.5, using a pH adjuster. The compounded polymer latex composition contains the polymer latex of the present invention, an optional pH adjuster (preferably ammonia or an alkali metal hydroxide), and commonly used additives optionally used in these compositions, selected from antioxidants, pigments, TiO2, fillers, and dispersants.

[0139] Alternatively, instead of compounding the polymer latex of the present invention, a polymer latex comprising the latex polymer (A) as defined above may be compounded in the same manner as described above, and a compound (B) as defined above may be added during or after the compounding step to provide the compounded latex composition of the present invention. Of course, all variations regarding the latex polymer (A), compound (B), and their relative amounts as described above may be used.

[0140] Conventional vulcanization systems can be added to the polymer latex compositions formulated according to the invention for use in dip molding methods, such as sulfur combined with accelerators (e.g., thiuram, urethane, and zinc oxide) to make them curable. Alternatively or additionally, crosslinking agent components can be added, such as polyvalent cations or other polyfunctional organic compounds suitable for reacting with functional groups on latex particles to achieve chemical crosslinking. However, a particular advantage of the invention is that sulfur vulcanization systems and crosslinking agents can be completely avoided, and the polymer latex formulations of the invention remain curable to provide dip-molded articles with the desired tensile properties. It is preferred to use polyvalent cations such as ZnO as additional crosslinking agent components to suitably adjust the mechanical properties of very thin elastomeric films, particularly those with a film thickness of at most 0.1 mm, preferably 0.01 to 0.1 mm, more preferably 0.03 to 0.08 mm.

[0141] In certain heavy-duty applications such as industrial gloves, in addition to the self-crosslinking properties of the polymer latex of the present invention, it may be advantageous to use a conventional sulfur vulcanization system as described above in order to further increase the mechanical strength of the dip-molded articles.

[0142] Method for preparing dip-molded articles:

[0143] In a suitable method for preparing dip-molded latex articles, a mold having the desired shape of the final article is first immersed in a coagulant bath containing a metal salt solution. The coagulant is typically used in solution form in water, alcohol, or mixtures thereof. Specific examples of coagulants include metal halides such as calcium chloride, magnesium chloride, barium chloride, zinc chloride, and aluminum chloride; metal nitrates such as calcium nitrate, barium nitrate, and zinc nitrate; metal sulfates such as calcium sulfate, magnesium sulfate, and aluminum sulfate; and acetates such as calcium acetate, barium acetate, and zinc acetate. Calcium chloride and calcium nitrate are most preferred. The coagulant solution may contain additives to improve the wetting behavior of the mold.

[0144] The mold is then removed from the bath and optionally dried. The mold, thus treated, is then immersed in the formulated latex composition according to the invention. Consequently, a film of latex coagulates on the surface of the mold. Alternatively, the latex film can be obtained through multiple immersion steps, particularly two sequential immersion steps.

[0145] Subsequently, the mold is removed from the latex composition and optionally immersed in a water bath to extract, for example, polar components from the composition and wash the coagulated latex film.

[0146] The latex-coated mold is then optionally dried at a temperature below 80°C.

[0147] Finally, the latex-coated mold is heat-treated at a temperature of 40-180°C and / or exposed to UV radiation to obtain the required mechanical properties of the final film product. The final latex film is then removed from the mold. The duration of the heat treatment will depend on the temperature and is typically between 1 and 60 minutes. Higher temperatures require shorter treatment times.

[0148] The inventors of this invention have surprisingly discovered that the dip molding method can be operated more economically when using the polymer latex of this invention. In particular, it has been found that the time between forming the latex compound according to the invention and performing the dip molding step (curing time) can be significantly reduced to 180 minutes or less compared to compounds made from standard latexes that require curing times much longer than 180 minutes.

[0149] Furthermore, the inventors have discovered that the temperature during the heat treatment step can be significantly reduced to a range of 40°C to less than 120°C without impairing the mechanical properties of the final dip-molded product. Conventional latexes require temperatures of 120°C and higher to achieve the desired mechanical properties. Therefore, when using the polymer latex of this invention, the dip molding method is more time-consuming and energy-efficient, making it more economical.

[0150] According to the present invention, it is therefore preferred that:

[0151] - In the mixing step (a)

[0152] (i) The polymer latex according to the invention is compounded by adjusting the pH to a range of 7 to 12, preferably 7.5 to 11, more preferably 8 to 10, and optionally by adding ZnO; or

[0153] (ii) By adjusting the pH to a range of 7 to 12, preferably 7.5 to 11, more preferably 8 to 10, and optionally by adding ZnO followed by pre-formed particles of the latex polymer (b) as defined above, a polymer latex comprising particles of the latex polymer (a) as defined above is compounded; or

[0154] (III) A polymer latex comprising particles of polymer (b) as defined above is formulated by adjusting the pH to a range of 7 to 12, preferably 7.5 to 11, more preferably 8 to 10, and optionally adding ZnO, and subsequently adding pre-formed particles of latex polymer (a) as defined above; and

[0155] The resulting compounded latex composition, free of sulfur-curing agents and sulfur-curing accelerators, is cured for less than 180 minutes, preferably 10 to 150 minutes, more preferably 20 to 120 minutes, and most preferably 30 to 90 minutes, before use in the impregnation step d); and / or

[0156] - In the heat treatment step h), the latex-coated mold is heat-treated at a temperature of 40°C to below 120°C, preferably 60°C to 100°C, and more preferably 70°C to 90°C.

[0157] The final heat-treated or UV-cured polymer latex film has a tensile strength of at least about 7 MPa and an elongation at break of at least about 300%, preferably at least about 10 MPa and at least about 350%, more preferably at least about 15 MPa and at least about 400%, and even more preferably at least about 20 MPa and at least about 500%. These mechanical properties are measured according to ASTM D412.

[0158] This method can be used for any latex product that can be produced by dip molding methods known in the art.

[0159] As an alternative, a cutting and sealing process can be used. In a first step, a continuous elastomeric film of polymer latex is prepared, for example by casting and optionally by heating and / or UV curing. In the next stage, two separate continuous elastomeric films are aligned, and then the aligned continuous elastomeric films are cut / stamped into a preselected shape to obtain two stacked layers of elastomeric films of the preselected shape. The stacked layers of elastomeric films are joined together at least at a preselected portion around the periphery of the stacked layers to form an elastomeric article. Joining can be performed using thermal means, preferably selected from heat sealing and welding or by gluing or a combination of heating and gluing.

[0160] This invention is particularly applicable to latex products selected from healthcare devices, such as surgical gloves, examination gloves, condoms, catheters, balloons and tubes, or all different kinds of industrial and household gloves.

[0161] Furthermore, the polymer latex of the present invention can also be used for coating and impregnation of substrates, preferably textile substrates. A suitable product obtained thereby is a fabric-supported glove.

[0162] The present invention will be further illustrated with reference to the following embodiments. Example

[0163] Determination of physical parameters:

[0164] The dispersion was characterized by measuring total solids content (TSC), pH value, gel content, viscosity (Brookfield LVT), and z-average particle size. In addition, the tensile properties of the final film were tested.

[0165] Determination of Total Solids (TSC):

[0166] The total solids content was determined by gravimetric method. 1–2 g of the dispersion was weighed into a balanced aluminum pan on an analytical balance. The pan was stored in a circulating air oven at 120°C for 1 hour until a constant mass was reached. After cooling to room temperature, the final weight was measured again. The solids content was calculated as follows:

[0167]

[0168] Where m 初始 = Initial mass of latex

[0169] m 最终 =Mass after drying

[0170] pH value measurement:

[0171] pH values ​​were determined according to DIN ISO 976. After two-point calibration using a buffer solution, the electrodes of the Schott CG 840 pH meter were immersed in a dispersion at 23°C, and the constant value displayed on the screen was recorded as the pH value.

[0172] Determination of gel content

[0173] The latex sample for testing was sieved through a white filter cloth to remove any skin or coagulation. The latex film was then cast onto a glass plate and spread using a coater until a film thickness of approximately 0.1–0.3 mm was obtained.

[0174] Place the glass plate in an air-circulating oven at 55–60°C for 2 hours. After drying, remove the polymer from the plate and cut it into small pieces. Weigh approximately 1 gram of the dried polymer into a 175 ml wide-mouth glass flask and record the polymer weight. Then add 100 ml (±1 ml) of MEK (methyl ethyl ketone) and a magnetic stir bar. Seal the flask with the cap and place it in a water bath on a magnetic stirrer set to 35°C. Stir continuously for 16 hours. Afterward, remove the sample from the water bath and allow it to cool to ambient temperature. Accurately weigh the shallow foil cup. Let the flask stand for a period of time to separate the solvent and undissolved polymer. Filter 15 ml of the solution through filter paper into a clear glass container, and then transfer 5 ml of this solution to the shallow foil cup using a pipette. In a fume hood, place the cup under an IR (infrared) lamp (115°C–120°C) for 30 minutes. Finally, remove the cup from the IR lamp and cool to room temperature, then weigh it again.

[0175] Weight of dried sample = A

[0176] Weight of shallow foil cup = B

[0177] Weight of shallow foil cup + dried contents = C

[0178] Solvent % TSC (W / V) = (CB) × 100 = D

[0179] Total weight of dissolved polymer (in 100 ml) = 100 × D / 100 E

[0180] Gel content % = (1 - E / A) × 100 (2)

[0181] Viscosity determination:

[0182] Latex viscosity was determined at 23°C using a Brookfield LVT viscometer. Approximately 220 mL of liquid (air-free) was filled into a 250 mL beaker, and the viscometer spindle was immersed in the markings on the spindle. The viscometer was then turned on, and the value was recorded after approximately 1 minute until it became constant. The viscosity range determines the selection of the spindle and rotation speed, as well as the factors used to calculate the recorded viscosity values. Information regarding the spindle used and revolutions per minute is shown in parentheses in Examples 1, 2, and 8.

[0183] Particle size (PS) determination:

[0184] z-uniform particle size was measured using dynamic light scattering with a Malvern Zetasizer Nano S (ZEN 1600). The latex sample was diluted with deionized water to the turbidity level described in the manual and transferred to a test cuvette. The cuvette was gently mixed to homogenize the sample and then placed in the measuring apparatus. This value was recorded as the software-generated z-uniform particle size.

[0185] Preparation of impregnated film:

[0186] Stir the latex, with or without compounding materials, at the desired pH value at room temperature for 3 hours, and then impregnate it with the coagulant as follows.

[0187] Wash the ceramic spatula or model with soap, then rinse thoroughly with deionized water, and then dry in an air-circulating oven set at 65-70°C (spatula temperature, 55-60°C) until dry.

[0188] A coagulant solution was prepared by dissolving calcium nitrate (18 wt%) and calcium carbonate (2 wt%) in deionized water.

[0189] The dry shovel or model is then immersed in a salt solution, removed, and dried in an air-circulating oven set at 70-75°C (shovel temperature, 60-65°C) until dry. The salt-coated shovel or model is then immersed in the desired latex mixture (total solids content 18% by weight and cured at room temperature for 24 hours after mixing) for 5 seconds, removed, and placed in an air-circulating oven set at 100°C for 1 minute to allow the film to gel. The gelled film is then washed in a deionized water tank set at 50-60°C for 1 minute, and then cured in an air-circulating oven set at 120°C for 20 minutes. Afterward, the cured / vulcanized film is cooled, removed from the shovel, and then aged in an air-circulating oven set at 100°C for 22 hours.

[0190] Finally, manually peel the cured gloves off the shovel or model; the typical dry film thickness is 0.056-0.066 mm.

[0191] The tensile strength properties of gloves made from latex were tested.

[0192] Determination of tensile strength properties of initial glove samples:

[0193] The tensile properties of vulcanized gloves were tested according to ISO 37-77 (5th edition, 2011-12-15). Dumbbell samples were cut from gloves made from each latex compound using an ISO 37-2 cutter (width of the narrow section = 4 mm, length of the narrow section = 25 mm, total length = 75 mm, and the thickness of the dumbbell is listed in the results table). The samples were then tested at an elongation rate of 500 mm / min on a Hounsfield HK10KS tension meter equipped with an H500LC elongation meter.

[0194] The tensile properties of the vulcanized gloves were also tested according to EN455-2, where dumbbell samples were cut from gloves made of each latex compound using a D-type cutter (width of the narrow section = 3 mm, length of the narrow section = 33 mm, total length = 100 mm, dumbbell thickness listed in the results table) and tested at a tensile rate of 500 mm / min on a Hounsfield HK10KS tension meter equipped with an H500LC extensometer. Stress values ​​were automatically reported by the machine software, as were modulus values ​​at given strains (typically 100, 300, and 500% strain). Results for unaged and aged (“aged” refers to samples placed in an oven at 100°C for 22 hours prior to tensile property testing) are recorded in Tables 2 and 3, respectively.

[0195] The following abbreviations are used in the embodiments:

[0196] MAA = Methacrylic acid

[0197] BD = Butadiene

[0198] ACN = Acrylonitrile

[0199] GMA = glycidyl methacrylate

[0200] tDDM = tert-dodecylthiol

[0201] Na4EDTA = Tetrasodium ethylenediaminetetraacetic acid

[0202] TBHP = tert-butyl hydroperoxide

[0203] TSC = Total Solids

[0204] PS = Granularity

[0205] ZnO = Zinc oxide

[0206] Unless otherwise stated, all parts and percentages below are based on weight.

[0207] Example 1: Preparation of carboxylated nitrile latex (low gel content) without ethylene oxide

[0208] Two parts by weight (based on polymer solids) of ethylene oxide-free seed latex (average particle size 36 nm) and 80 parts by weight of water (based on 100 parts by weight of monomers including the seed latex) were added to a nitrogen-purged autoclave, which was then heated to 30°C. Then, 0.01 parts by weight of Na₄EDTA and 0.005 parts by weight of Bruggolite FF6 dissolved in 2 parts by weight of water were added, followed by 0.08 parts by weight of sodium persulfate dissolved in 2 parts by weight of water. Then, over a 4-hour period, monomers (35 parts by weight of acrylonitrile, 58 parts by weight of butadiene, and 5 parts by weight of methacrylic acid) were added together with 0.6 parts by weight of tDDM. Over a 10-hour period, 2.2 parts by weight of sodium dodecylbenzenesulfonate, 0.2 parts by weight of tetrasodium pyrophosphate, and 22 parts by weight of water were added. Over a 9-hour period, 0.13 parts by weight of Bruggolite FF6 in 8 parts by weight of water were added as an activator feed. The temperature was maintained at 30°C until 95% conversion was achieved, resulting in a total solids content of 45%. Polymerization was briefly stopped by adding 0.08 parts by weight of a 5% diethylhydroxylamine aqueous solution. The pH was adjusted to 7.5 using potassium hydroxide (5% aqueous solution), and residual monomers were removed by vacuum distillation at 60°C. 0.5 parts by weight of Wingstay L-type antioxidant (60% dispersion in water) was added to the unprocessed latex, and the pH was adjusted to 8.2 by adding a 5% potassium hydroxide aqueous solution.

[0209] Example 1 yielded the following characterization results:

[0210] TSC = 44.9% by weight

[0211] pH = 8.2

[0212] Tg = -18℃

[0213] Gel content = 0%

[0214] Viscosity = 38 mPas (1 / 60)

[0215] Particle size, P z =121nm

[0216] Example 2: Preparation of ethylene oxide functionalized latex

[0217] 2.0 parts by weight of diphenyl ether disulfonate (relative to 100 parts by weight of monomer) dissolved in 185 parts by weight of water were added to a nitrogen-purged autoclave, and the mixture was heated to 70°C. 0.1 parts by weight of tDDM and 0.05 parts by weight of Na4EDTA were added to the initial feed, along with 0.7 parts by weight of ammonium persulfate (12% aqueous solution) in aliquots. Then, over a 6.5-hour period, a solution of 45.4 parts by weight of butadiene, 14.6 parts by weight of acrylonitrile, and 5.0 parts by weight of diphenyl ether disulfonate dissolved in 50 parts by weight of water was added. After 1 hour, 40 parts by weight of GMA were added over another 6.5 hours. The temperature was maintained at 70°C after the monomer addition. Polymerization was maintained up to 99% conversion. The reaction mixture was cooled to room temperature and sieved through a 90 μm filter.

[0218] Example 2 yielded the following characterization results:

[0219] TSC = 37.7% by weight

[0220] pH = 7.1

[0221] Tg = -9℃

[0222] Gel content = 96%

[0223] Viscosity = 15 mPas (1 / 60)

[0224] Particle size, P z =39nm

[0225] Example 3: (Comparison, WO 2017 / 209596)

[0226] An equal sample of Example 2 (ethylene oxide functionalized latex) was added to an equal sample of Example 1 (XNBR latex without ethylene oxide) so that the blending ratio of Example 1 to Example 2 was 90:10 on a wet weight basis.

[0227] Using an aqueous potassium hydroxide solution, a portion of XNBR latex was adjusted to pH 10 and mixed with 1 phr of zinc oxide and 1 phr of titanium dioxide. The mixture was then adjusted to a concentration of 18% by weight solids and stirred for 3 hours. The impregnated film was prepared as described above.

[0228] Example 4: Compound (B) (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane) with 1 phr, No ZnO

[0229] Add 1 phr of 2-hydroxy-1-aryloxy-3-methacryloxypropane to an aliquot of Example 1 (XNBR latex without ethylene oxide) and stir thoroughly for 2 hours.

[0230] The pH of the latex was adjusted to 10 and mixed using a potassium hydroxide solution. The mixture was then impregnated with a dry salt spatula and processed according to the scheme given in Example 3, except that zinc oxide was not added.

[0231] Example 5: Compound (B) (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane) with 1 phr, With ZnO

[0232] Add 1 phr of 2-hydroxy-1-aryloxy-3-methacryloxypropane to an aliquot of Example 1 (XNBR latex without ethylene oxide) and stir thoroughly for 2 hours.

[0233] Using a potassium hydroxide solution, the latex was adjusted to pH 10 and mixed, then impregnated with a dry salt spatula and processed according to the scheme given in Example 3.

[0234] Example 6: Compound (B) with 2 phr (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane), With ZnO

[0235] Same as in Example 5, except that 2 phr of 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane is added.

[0236] Example 7: Compound (B) with 3 phr (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane), With ZnO

[0237] Same as in Example 5, except that 3 phr of 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane is added.

[0238] Example 8: Compound (B) with 5 phr (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane), With ZnO

[0239] Same as Example 5, except that 5 phr of 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane is added.

[0240] Table 1 summarizes the gel content data of some latex samples before impregnation.

[0241] Table 1

[0242] latex Gel content (%) Example 1 10 Example 2 97 Example 3 45 Example 7 21

[0243] The tensile strength data of the prepared membranes were measured as described above and summarized in Tables 2 and 3.

[0244] Table 2: Results of Examples 3-8 before aging

[0245]

[0246] Table 3: Aging Results of Examples 3-8

[0247]

[0248] As shown in Table 2, the elongation at break increased from 645% to 713% when the level of 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane increased from 1 phr to 5 phr. The softening effect from the crosslinking agent was also confirmed by the corresponding decrease in 300% modulus from 3.9 MPa to 2.9 MPa. Notably, both tensile strength and breaking force decreased significantly in the absence of ZnO in the formulation. A similar trend was observed in the aging results shown in Table 3, where compound (B) with 5 phr in the presence of ZnO achieved the highest elongation at break and the lowest 300% modulus.

[0249] Example 9: Preparation of carboxylated nitrile latex without ethylene oxide

[0250] Two parts by weight (based on polymer solids) of ethylene oxide-free seed latex (average particle size 36 nm) and 80 parts by weight of water (based on 100 parts by weight of monomers including the seed latex) were added to a nitrogen-purged autoclave, which was then heated to 30°C. Then, 0.01 parts by weight of Na₄EDTA, 0.005 parts by weight of Bruggolite FF6, and 0.3 parts by weight of tDDM dissolved in 2 parts by weight of water were added, followed by 0.08 parts by weight of sodium persulfate dissolved in 2 parts by weight of water. The monomers (35 parts by weight of acrylonitrile, 56 parts by weight of butadiene, and 7 parts by weight of methacrylic acid) were then added with 0.45 parts by weight of tDDM over a 6-hour period, except for a 4.5-hour period for tDDM. Over a 10-hour period, 2.2 parts by weight of sodium dodecylbenzenesulfonate, 0.2 parts by weight of tetrasodium pyrophosphate, and 22 parts by weight of water were added. Add 0.13 parts by weight of Bruggolite FF6 as an activator feed in 8 parts by weight of water over 9 hours. Maintain the temperature at 30°C until 95% conversion is achieved, resulting in a total solids content of 45%. Briefly stop the polymerization by adding 0.08 parts by weight of a 5% aqueous solution of diethylhydroxylamine. Adjust the pH to 7.5 using potassium hydroxide (5% aqueous solution) and remove residual monomers by vacuum distillation at 60°C. Add 0.5 parts by weight of Wingstay L-type antioxidant (60% dispersion in water) to the unprocessed latex and adjust the pH to 8.2 by adding a 5% aqueous solution of potassium hydroxide.

[0251] Example 9 yielded the following characterization results:

[0252] TSC = 44.5% by weight

[0253] pH = 8.3

[0254] Tg = -13℃

[0255] Viscosity = 50 mPas (1 / 60)

[0256] Particle size, P z =127nm

[0257] Example 10: (Comparison)

[0258] An equal sample of Example 2 (ethylene oxide functionalized latex) was added to an equal sample of Example 9 (XNBR latex without ethylene oxide) so that the blending ratio of Example 9 to Example 2 was 90:10 on a wet weight basis.

[0259] A portion of the XNBR latex was adjusted to pH 9.5 using an aqueous potassium hydroxide solution and then mixed with 1 phr of zinc oxide and 1 phr of titanium dioxide. The mixture was then adjusted to a concentration of 18% by weight solids and stirred for 3 hours.

[0260] Before gelling the membrane at 100°C for 1 minute, immerse the dried salt-coated model in the prepared latex solution, wash with deionized water for 1 minute (in a tank set at 50-60°C) for 1 minute, and then dry and cure / vulcanize in an air-circulating oven set at 120°C for 20 minutes to ensure complete drying and crosslinking formation. Prepare the impregnated membrane as described above.

[0261] Example 11: Compound (B) with 1 phr (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane).

[0262] Add 1 phr of 2-hydroxy-1-aryloxy-3-methacryloxypropane to an aliquot of Example 15 (XNBR latex without ethylene oxide) and stir thoroughly for 2 hours.

[0263] Using a potassium hydroxide solution, the latex was adjusted to a pH of 9.5 and mixed, then impregnated with a dry salt-coated mold and processed according to the scheme given in Example 10.

[0264] Example 12: (Comparison)

[0265] An equal sample of Example 2 (ethylene oxide functionalized latex) was added to an equal sample of Example 9 (XNBR latex without ethylene oxide) so that the blending ratio of Example 9 to Example 2 was 90:10 on a wet weight basis.

[0266] Using an aqueous potassium hydroxide solution, a portion of the XNBR latex was adjusted to a pH of 9.5 and mixed with 1 phr of zinc oxide and 1 phr of titanium dioxide. The mixture was then adjusted to a concentration of 18 wt% solids and stirred for 3 hours. The impregnated film was prepared as described above, except that the curing temperature was 70°C instead of 120°C.

[0267] Example 13: Compound (B) with 1 phr (2-hydroxy-1-acryloyloxy-3-methacryloyloxypropyl)

[0268] Add 1 phr of 2-hydroxy-1-aryloxy-3-methacryloxypropane to the aliquot of Example 9 (XNBR latex without ethylene oxide) and stir thoroughly for 2 hours.

[0269] Using a potassium hydroxide solution, the latex was adjusted to a pH of 9.5 and mixed, then impregnated with a dry salt-coated mold and processed according to the scheme given in Example 12.

[0270] The tensile properties of the vulcanized gloves were tested as described above. The results for unaged and aged gloves are reported in Tables 4 and 5, respectively.

[0271] Table 4: Results of Examples 10-13 before aging

[0272]

[0273] Table 5: Aging Results of Examples 10-13

[0274]

[0275] As shown in Table 4, the samples containing 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane exhibited higher elongation at break than their respective comparative examples. For instance, Example 11 showed an elongation at break of 640%, significantly higher than the 556% of Comparative Example 10. The lower 300% and 500% moduli of all samples (i.e., Examples 11 and 13) in the unaged results in Table 4 and the aging results in Table 5 corroborate not only the elongation at break but also the softness of the material derived from 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane. Furthermore, it was surprisingly found that 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane provides excellent performance at lower curing temperatures, even for ultrathin gloves. For example, the glove from Example 13 achieved a breaking force of at least 6 Newtons at a very low glove thickness of <0.050 mm.

Claims

1. A polymer latex for preparing an elastomer film, comprising: (A) Particles of a latex polymer (A), which is obtained by free radical emulsion polymerization of a mixture of olefinically unsaturated monomers, the latex polymer containing multiple functional groups (x). The monomer composition for latex polymer (A) comprises: (a) 15 to 99% by weight of conjugated dienes; (b) 1 to 80% by weight of monomers selected from olefinic unsaturated nitrile compounds; (c) Up to 10% by weight of olefinic unsaturated compounds that are different from conjugated dienes and have functional groups (x); (d) 0 to 80% by weight of vinyl aromatic monomers; and (e) 0 to 65% by weight of alkyl esters of olefinic unsaturated acids The weight percentage is based on the total weight of the monomers in the monomer mixture. The functional groups (x) on the latex polymer (A) are selected from groups having carbon-carbon double bonds, carboxylic acid functional groups, hydroxyl groups, epoxy groups, acetoacetyl groups, primary or secondary amino groups, acetoxy groups, isocyanate groups, alkoxysilyl groups, alkoxy groups, dioxane-pentanone functional groups, and combinations thereof; and (B) A compound having a β-hydroxy ester bond and at least one additional functional group (y) that is reactive to the functional group (x) on the latex polymer (A).

2. The polymer latex according to claim 1, wherein... (a) The conjugated diene is selected from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and combinations thereof; (b) The olefinic unsaturated nitrile compound is selected from (meth)acrylonitrile, α-cyanoethylacrylonitrile, fumaronitrile and combinations thereof; (c) Unlike conjugated dienes, olefinic unsaturated compounds with functional groups (x) are selected from... (c1) An olefinic unsaturated compound having at least two different olefinic unsaturated groups; (c2) Alkenyl unsaturated acids and their salts, polycarboxylic anhydrides, polycarboxylic acid ester monomers, carboxyl alkyl esters of alkenyl unsaturated acids and combinations thereof. (c3) Hydroxyl-functional olefinic unsaturated compounds; (c4) Ethylene oxide-functionalized olefinic unsaturated compounds; (c5) Acetylacetyl functional olefinic unsaturated compounds; (c6) An alkene-bonded unsaturated compound containing a primary or secondary amino group. (c7) Acetoxyl-functionalized alkene-bonded unsaturated compounds; (c8) Isocyanate-functionalized alkene-bonded unsaturated compounds; (c9) Alkoxysilyl-functionalized alkene-bonded unsaturated compounds; (c10) Alkoxy-functional alkene-bonded unsaturated compounds; (c11) Dioxacyclopentanone-functional olefinic unsaturated compounds; and their combinations; (d) The vinyl aromatic monomers are selected from styrene, α-methylstyrene and combinations thereof; (e) The alkyl ester of the olefinic unsaturated acid is selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. and their combinations; The mixture of olefinically unsaturated monomers for use in latex polymer (A) optionally comprises olefinically unsaturated monomers selected from the following: (f) Vinyl carboxylate; (g) A monomer having at least two identical olefinic unsaturated groups; and Their combination.

3. The polymer latex according to any one of the preceding claims, wherein the mixture of olefinically unsaturated monomers for the latex polymer (a) comprises: - From 20 to 99% by weight of conjugated dienes; -Monomers selected from olefinic unsaturated nitrile compounds, ranging from 1 to 60% by weight; -Vinyl aromatic monomers from 0 to 70% by weight; - From 0 to 25% by weight of (meth)acrylate C1-C8 alkyl esters; - From 0.05 to 7 wt% olefinic unsaturated acids; and -Vinyl esters from 0 to 10% by weight: The weight percentage is based on the total weight of the monomers in the monomer mixture.

4. The polymer latex according to claim 1 or 2, wherein the functional group (y) in the compound (B) that is reactive to the functional group (x) on the latex polymer (A) is selected from carbon-carbon double bonds, epoxy groups, thiols, hydroxyl groups, primary or secondary amino groups, isocyanates, oxazolinyl groups, aziridinyl groups, imino groups, carbodiimides, ester groups, acetoxy groups, carboxylic acid groups, alkoxysilyl groups, dioxanepentanone groups, acylhydrazine groups, and combinations thereof.

5. The polymer latex according to claim 1 or 2, wherein the functional group (y) in compound (B) is at the terminal position.

6. The polymer latex according to claim 1 or 2, wherein - The functional group (x) is selected from groups having carbon-carbon double bonds, and the functional group (y) is selected from groups having carbon-carbon double bonds and thiols; or - The functional group (x) is selected from carboxylic acid functional groups, and the functional group (y) is selected from epoxy, thiol, hydroxyl, primary or secondary amino, isocyanate, oxazolinyl, aziridinyl, imino, carbodiimide, ester, and acetoxy; or - The functional group (x) is selected from hydroxyl, and the functional group (y) is selected from alkoxysilyl, carboxylic acid; isocyanate, primary or secondary amino, and ester group; or - The functional group (x) is selected from an epoxy group, and the functional group (y) is selected from a carboxylic acid functional group, a hydroxyl group, and an ester group; or - The functional group (x) is selected from acetoacetyl, and the functional group (y) is selected from groups having carbon-carbon double bonds, isocyanates, and primary or secondary amino groups; or - The functional group (x) is selected from primary or secondary amino groups, and the functional group (y) is selected from carboxylic acid functional groups, epoxy groups, ester groups, and dioxane-pentanone groups; or - The functional group (x) is selected from acetoxy, and the functional group (y) is selected from hydrazide and primary or secondary amino groups; or - The functional group (x) is selected from isocyanate groups, and the functional group (y) is selected from carboxylic acid groups, hydroxyl groups, primary or secondary amino groups, and thiols; or - The functional group (x) is selected from alkoxysilyl groups, and the functional group (y) is selected from hydroxyl and alkoxysilyl groups; or - The functional group (x) is selected from alkoxy groups, and the functional group (y) is selected from ester groups; or - The functional group (x) is selected from an ester group, and the functional group (y) is selected from a hydroxyl group, a carboxylic acid group, and an ester group; or - The functional group (x) is selected from the dioxane pentanone group, and the functional group (y) is selected from the primary amino or secondary amino group.

7. The polymer latex according to claim 1 or 2, wherein compound (B) is selected from glycerol dimethacrylate (GDMA), glycerol 1,3-diglyceride diacrylate (GDGDA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate, bisphenol A glyceride diacrylate, methyl ethyl ether propionate (KEMA), glycerol monomethacrylate, fatty acid modified glycidyl methacrylate, bisphenol A glyceride diacrylate, (meth)acrylate 2-hydroxy-3-phenoxypropyl, eugenyl-2-hydroxypropyl methacrylate, and combinations thereof.

8. The polymer latex according to claim 1 or 2, wherein the latex polymer (A) particles are present in an amount of 80 to 99.9% by weight, and the compound (B) is present in an amount of 0.1 to 20% by weight, based on the total weight of the latex polymer (A) and the compound (B).

9. A method for preparing polymer latex, the method comprising: (i) In an emulsion polymerization method, a mixture of olefinically unsaturated monomers for a latex polymer (A) is polymerized to obtain a latex, the mixture containing at least one monomer that, upon polymerization, results in a functional group (x), the latex comprising particles of the latex polymer (A) having a plurality of functional groups (x). The monomer composition for latex polymer (A) comprises: (a) 15 to 99% by weight of conjugated dienes; (b) 1 to 80% by weight of monomers selected from olefinic unsaturated nitrile compounds; (c) Up to 10% by weight of olefinic unsaturated compounds that are different from conjugated dienes and have functional groups (x); (d) 0 to 80% by weight of vinyl aromatic monomers; and (e) 0 to 65% by weight of alkyl esters of olefinic unsaturated acids The weight percentage is based on the total weight of the monomers in the monomer mixture. The functional groups (x) on the latex polymer (A) are selected from groups having carbon-carbon double bonds, carboxylic acid functional groups, hydroxyl groups, epoxy groups, acetoacetyl groups, primary or secondary amino groups, acetoxy groups, isocyanate groups, alkoxysilyl groups, alkoxy groups, dioxane-pentanone functional groups, and combinations thereof; and (ii) Adding a compound (B) having a β-hydroxy ester bond and at least one additional functional group (y) that is reactive with the functional group (x) on the latex polymer (A).

10. The method of claim 9, wherein the latex polymer (A) and / or the compound (B) and / or their relative amounts are as defined in any one of claims 1-8.

11. Use of the polymer latex according to any one of claims 1-8 in the production of elastomer articles or for coating or impregnating substrates.

12. A compounded latex composition suitable for producing dip-molded articles, comprising a polymer latex according to any one of claims 1-8 and an auxiliary agent optionally selected from sulfur vulcanizing agents, sulfur vulcanizing accelerators, polyvalent cations, free radical initiators, and combinations thereof.

13. The compounded latex composition according to claim 12, which is free of sulfur vulcanizing agents and sulfur vulcanization accelerators, and optionally contains polyvalent cations.

14. A method for preparing an impregnated molded article, the method comprising: a) Provides the compounded latex composition according to any one of claims 12 or 13; b) Immerse the mold with the desired shape of the final product in a coagulant bath containing a metal salt solution; c) Remove the mold from the coagulant bath and optionally dry the mold; d) Immerse the mold treated in steps b) and c) into the compounded latex composition of step a); e) Allow the latex film on the mold surface to solidify; f) Remove the latex-coated mold from the compounded latex composition and optionally immerse the latex-coated mold in a water bath; g) Optionally dry the latex-coated mold; h) Heat-treating the latex-coated mold obtained in step e) or f) at a temperature of 40°C to 180°C; and / or exposing the latex-coated mold obtained in step e) or f) to UV radiation; i) Remove the latex product from the mold.

15. A method for preparing an elastomer article, the method comprising: -A continuous elastomer film is obtained from the polymer latex according to any one of claims 1 to 8; -Optional geothermal treatment of the continuous elastomer membrane and / or exposure of the continuous elastomer membrane to UV radiation; - Align two separate continuous elastomer membranes; - Cut or stamp aligned continuous elastomeric membranes into a preselected shape to obtain two stacked layers of the preselected elastomeric membrane; - The stacked layers are joined together at least a pre-selected portion of the periphery to form an elastomeric article.

16. The method of claim 15, wherein the joining is performed by means of heat, or by gluing, or a combination of heat and gluing.

17. An article made by using a polymer latex according to any one of claims 1 to 8 or a compounded latex composition according to any one of claims 12 or 13.

18. The article of claim 17, wherein the article is selected from surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric support gloves, household glove balloons, and tubes.

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