XNBR polymer formed using a free radical polymerization agent

Abstract

The present invention relates to a polymer latex containing a copolymer, a method for preparing such a polymer latex, the use of the polymer latex for the production of rubber articles, and an article produced by using the polymer latex.

Description

Technical Field

[0001] The present invention relates to polymer latexes, methods for obtaining polymer latexes, and the use of polymer latexes for the preparation of rubber articles. The present invention also relates to rubber articles prepared from such polymer latexes or prepared by such methods from polymer latexes.

Background Art

[0002] XNBR (carboxylated nitrile butadiene rubber) has been known in the art for many years. Such rubbers are generally produced by free radical emulsion polymerization of butadiene, ethylenically unsaturated compounds having nitrile groups, and ethylenically unsaturated compounds having carboxyl groups.

[0003] However, this procedure has several drawbacks. First, for example, while a certain monomer should preferably be distributed towards one or both ends of the polymer chain, the distribution of monomers present in the resulting rubber is random, which does not allow for a specific monomer distribution throughout the final polymer. This problem can be partially overcome by providing block copolymers, but this procedure is often inefficient and thus requires multiple polymerization steps which are undesirable.

[0004] Furthermore, conventional emulsion polymerization requires the presence of a surfactant to enable the formation of micelles in which polymerization can occur. However, the presence of the surfactant in the resulting polymer latex often causes problems during the subsequent manufacture of some rubber articles, such as nitrile rubber gloves. Therefore, the surfactant needs to be at least partially removed from the resulting polymer latex which requires a large amount of water. Approximately 300 - 400 liters of water are required to produce 1000 gloves.

[0005] Therefore, for both economic and ecological reasons, it is necessary to overcome the drawbacks of the processes known in the art.

[0006] Therefore, an object of the present invention is to provide a polymer latex that can specifically manipulate the monomer distribution and does not necessarily require the presence of a surfactant during production, thereby enabling a more economical and environmentally friendly production method. SUMMARY OF THE INVENTION

[0007] The following paragraphs summarize some aspects of the present invention.

[0008] According to a first aspect, the present invention relates to a polymer latex comprising a copolymer obtained by free radical emulsion polymerization of a mixture of compounds comprising the following components: (a) A macro-reversible addition-fragmentation chain-transfer (macro-RAFT) agent, which can be obtained by free radical polymerization of a RAFT agent (a1) and an ethylenically unsaturated monomer (a2) having at least one functional group of acid, hydroxyl, ester, ether, amine, sulfonate and / or amide, (b) An ethylenically unsaturated monomer having a nitrile functional group, and (c) A conjugated diene monomer.

[0009] The mixture of compounds may further (d) comprise at least one ethylenically unsaturated monomer having a functional group of acid, hydroxyl, ester, ether, amine, sulfonate and / or amide. In particular, the compound (d) may be an ethylenically unsaturated monomer having at least a functional group of carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate.

[0010] The RAFT agent (a1) can contain a compound having a thiocarbonyl functional group.

[0011] The thiocarbonyl functional group can include the functional groups of trithiocarbonate, dithioester, thiocarbamate and / or xanthate.

[0012] The macro-RAFT agent (a) can induce polymerization-induced self-assembly (PISA).

[0013] The monomer (b) includes monomers having a total of 3 to 10 carbon atoms or combinations thereof, preferably includes acrylonitrile, butyronitrile or combinations thereof, and more preferably can include acrylonitrile.

[0014] Monomer (c) can include 1,3-butadiene, isoprene, 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-1,3,6-octatriene, 2-methyl-6-methylene-1,7-octadiene, 7-methyl-3-methylene-1,6-octadiene, 1,3,7-octatriene, 2-ethyl-1,3-butadiene, 2-amyl-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-dodecatetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, 2,6-dimethyl-2,4,6-octatriene, 2-phenyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, 1,3-cyclohexadiene, myrcene, ocimene, farnesene, or a combination thereof, preferably 1,3-butadiene, isoprene, or a combination thereof, more preferably can include 1,3-butadiene.

[0015] Monomer (a2) and / or (d) can include a monomer of the general formula R 1 C(=CH2)R 2 X, where in the formula, R 1 is H, methyl or ethyl, R 2 is an arbitrary spacer group of a straight chain or branched chain having 1 to 5 carbon atoms, X is a functional group of carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate, preferably R 1 is H or methyl, X is a carboxylic acid, more preferably monomer (a2) and / or (d) can include acrylic acid or methacrylic acid, and most preferably monomer (a2) and / or (d) can include methacrylic acid.

[0016] The copolymer may include a portion having an X-Y structure or an X-Y-Z structure.

[0017] Section Y can have a random structure or a block structure containing monomers (b) and (c), and optionally, section Y can further include monomer (a2) and / or (d).

[0018] Section X, and section Z if present, can include monomer (a2) and / or (d), and preferably, sections X and Z do not include monomers (b) and (c).

[0019] The content of monomer (b) in the mixture of compounds can be 15 to 60 parts by weight, preferably 20 to 50 parts by weight, based on the weight of the mixture of compounds.

[0020] The content of monomer (c) in the mixture of compounds can be 40 to 90 parts by weight, preferably 50 to 80 parts by weight, based on the weight of the mixture of compounds.

[0021] The macro-RAFT agent (a) can be present in an amount of 1.5 to 10 parts by weight, preferably 1.75 to 8 parts by weight, more preferably 2 to 6 parts by weight, based on the weight of the mixture of compounds.

[0022] Monomer (d) can be present in an amount of 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, more preferably 1.5 to 10 parts by weight, based on the weight of the mixture of compounds.

[0023] The polymer latex can further include a surfactant, and the content of the surfactant in the polymer latex can be less than 5 parts by weight, preferably less than 3.5 parts by weight, more preferably less than 3 parts by weight, and most preferably less than 2.5 parts by weight, based on the total weight of the polymer latex.

[0024] The polymer latex may be a surfactant-free polymer latex.

[0025] According to a second aspect, the present invention relates to a method for producing a polymer latex containing a block copolymer, the method comprising the following steps: (1) Obtaining a macro-RAFT agent (a) by free radical polymerization of a RAFT agent (a1) and an ethylenically unsaturated monomer (a2) having at least one functional group of acid, hydroxyl, ester, ether, amine, sulfonate and / or amide; (2) Obtaining a polymer latex by RAFT-mediated emulsion polymerization of a mixture of compounds containing the following components: (a) The macro-RAFT agent (a) obtained in step (1); (b) An ethylenically unsaturated monomer having a nitrile functional group, and (c) A conjugated diene monomer.

[0026] This method may further include adding at least one ethylenically unsaturated monomer (a2) and / or (d) having at least one functional group of acid, hydroxyl, ester, amine and / or amide to the reaction mixture during and / or after step (2). Preferably, the monomer (a2) and / or (d) is an ethylenically unsaturated monomer having at least one functional group of acid, hydroxyl, ester, ether, amine, sulfonate and / or amide. More preferably, the monomers (a2) and (d) include a monomer of the general formula R 1 C(=CH2)R 2 X, wherein R 1 is H, methyl or ethyl, R 2 is an optional spacer group, linear or branched, having 1 to 5 carbon atoms, and X is a functional group of carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate. Preferably, R 1is H or methyl, X is a carboxylic acid, more preferably monomer (a2) and / or (d) contains acrylic acid or methacrylic acid, and most preferably monomer (a2) and / or (d) contains methacrylic acid.

[0027] Monomers (b), (c) and (d) can be charged by batch, semi-batch, continuous, split charging or split injection.

[0028] According to a second aspect, at least one of the following can be satisfied: (i) The ethylenically unsaturated monomer (a2) having at least one functional group of acid, hydroxyl, ester, ether, amine, sulfonate and / or amide contains the monomers defined above. (ii) Monomer (b) is the monomer defined above. (iii) Monomer (c) is the monomer defined above. (iv) Monomer (d) is an ethylenically unsaturated monomer having at least one functional group of acid, hydroxyl, ester, ether, amine, sulfonate and / or amide, preferably the general formula R 1 C(=CH2)R 2 X monomer, wherein R 1 is H, methyl or ethyl, R 2 is an optional spacer group of straight or branched chain having 1 to 5 carbon atoms, X is a functional group of carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate, preferably R 1 is H or methyl, X is a carboxylic acid, more preferably monomer (d) contains acrylic acid or methacrylic acid, and most preferably monomer (d) contains methacrylic acid. (v) The copolymer contains the sections defined above.

[0029] According to a second aspect, a surfactant may not be added before, during or after steps (1) and (2).

[0030] According to the second aspect, seeding agents may not be added before, during or after steps (1) and (2).

[0031] The polymerization in step (2) can be carried out at a temperature of 5°C to 95°C, preferably 30°C to 60°C.

[0032] In a third aspect, the present invention relates to the use of a polymer latex according to any of the clauses of the first aspect, or a polymer latex prepared by the method according to any of the clauses of the second aspect, for the preparation of a rubber article.

[0033] The rubber article can include surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-supported gloves, household gloves, balloons, tubes, dental dams, aprons, and pre-formed gaskets.

[0034] In a fourth aspect, the present invention relates to a rubber article prepared from a polymer latex according to any of the clauses of the first aspect, or a polymer latex prepared by the method according to any of the clauses of the second aspect.

[0035] The rubber article can include surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-supported gloves, household gloves, balloons, tubes, dental dams, aprons, and pre-formed gaskets.

Mode for Carrying Out the Invention

[0036] Detailed Description of the Invention The present invention relates to a polymer latex useful for the manufacture of rubber articles. The polymer latex contains a copolymer obtained by free radical emulsion polymerization of a mixture of compounds. This mixture of compounds includes (a) a macro reversible addition fragmentation chain transfer (macro-RAFT) agent, (b) an ethylenically unsaturated monomer having a nitrile functional group, and (c) a conjugated diene monomer. The macro-RAFT agent (a) can be obtained by free radical polymerization of a RAFT agent (a1) and an ethylenically unsaturated monomer (a2) having at least one functional group of an acid, hydroxyl, ester, ether, sulfonate and / or amide. The mixture of compounds preferably further includes (d) at least one ethylenically unsaturated monomer having a functional group of an acid, hydroxyl, ester, ether, sulfonate and / or amide.

[0037] Surprisingly, by using a macro reversible addition fragmentation chain transfer (macro-RAFT) agent (a) as an additional component during the production of the polymer latex by free radical emulsion polymerization, despite there being only a small amount of surfactant or no surfactant at all in the mixture of compounds during polymerization compared to conventional emulsion polymerization, a stable polymer latex can be obtained due to polymerization-induced self-assembly (PISA). A further advantage of the present invention is that the copolymer present in the polymer latex of the present invention can be specifically designed by the manufacturer, i.e., the monomer distribution in the copolymer can be manipulated according to the amount and time at which each monomer is added to the mixture of compounds during the polymerization process.

[0038] The macro-RAFT agent (a) can be obtained by free radical polymerization of a RAFT agent (a1) and an ethylenically unsaturated monomer (a2) having at least one functional group of an acid, hydroxyl, ester, ether, sulfonate and / or amide.

[0039] The macro-RAFT agent (a) can have an M of at least 500 g / mol, preferably 750 g / mol, more preferably 1000 g / mol and at most 5000 g / mol, preferably 4750 g / mol, more preferably 4500 g / mol. W One of ordinary skill in the art will understand that any range formed by either the explicitly disclosed lower or upper limits is explicitly encompassed herein. Thus, the macro-RAFT agent (a) can particularly have an M of from 500 g / mol to 5000 g / mol, preferably from 750 g / mol to 4750 g / mol, more preferably from 1000 g / mol to 4500 g / mol. W One of ordinary skill in the art will understand that M can be measured using techniques generally known in the art, including size exclusion chromatography and mass spectrometry using appropriate standards. W

[0040] The macro-RAFT agent (a) can be present in the mixture of compounds in an amount of from 1 to 10 parts by weight, preferably from 1.75 to 8 parts by weight, more preferably from 2 to 6 parts by weight, based on the weight of the mixture of compounds. Thus, the lower limit of the amount of the macro-RAFT agent (a) can be 1, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, or 2.0 parts by weight based on the weight of the mixture of compounds. The upper limit of this amount can be 10, 9.5, 9, 8.5, 8, 7.5, 7, 6. .5, or 6 parts by weight based on the weight of the mixture of compounds. One of ordinary skill in the art will understand that any range formed by either the explicitly disclosed lower or upper limits is explicitly encompassed herein.

[0041] The RAFT agent (a1) can contain a compound having a thiocarbonyl functional group. Preferably, the thiocarbonyl functional group can contain a functional group of trithiocarbonate, dithioester, thiocarbamate, and / or xanthate. Commercially available examples of the RAFT agent (a1) include, for example, 4-((((2-carboxyethyl)thio)carbonothioyl)thio)-4-cyanopentanoic acid, 4-((((2-carboxyethyl)thio)carbonothioyl)thio)-4-acetamidopentanoic acid, 2,2'-[carbonothiylbis(thio)]bis[2-methylpropanoic acid], 3-((((1-carboxyethyl)thio)carbonothioyl)thio)propanoic acid, bis(dodecylsulfanylthiocarbonyl)disulfide, cyanomethyl(3,5-dimethyl-1H-pyrazole)-carbodithioate, and dibenzyl trithiocarbonate. However, those skilled in the art will understand that any RAFT agent may be suitable for obtaining the polymer latex according to the present invention.

[0042] The monomer (a2) and / or the optionally present monomer (d) may be the same or different monomers. These monomers can preferably be selected from ethylenically unsaturated acids and their salts, hydroxy-functional ethylenically unsaturated monomers, ethylenically unsaturated monomers having a primary or secondary amino group, ethylenically unsaturated monomers having an amide group, hydroxylamine-functional ethylenically unsaturated monomers, glycol-functional ethylenically unsaturated monomers, and combinations thereof.

[0043] The ethylenically unsaturated acids and their salts can preferably be selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphorus-containing acids and their salts, polycarboxylic acid anhydrides, polycarboxylic acid partial ester monomers, carboxyalkyl esters of ethylenically unsaturated acids, and combinations thereof.

[0044] The hydroxy-functional ethylenically unsaturated monomer can preferably be selected from allyl alcohol, vinyl alcohol, N-methylolacrylamide, 1-penten-3-ol, hydroxyalkyl esters of ethylenically unsaturated acids, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, and combinations thereof.

[0045] The ethylenically unsaturated monomer having a primary amino group, a secondary amino group and / or an amide group can preferably be selected from (meth)acrylamide, 2-aminoethyl (meth)acrylate hydrochloride, 2-aminoethyl (meth)acrylamide hydrochloride, N-ethyl (meth)acrylamide, N-(3-aminopropyl)(meth)acrylamide hydrochloride, N-hydroxyethyl (meth)acrylamide, N-3-(dimethylamino)propyl (meth)acrylamide, [3-(methacryloylamino)propyl]trimethylammonium salt, N-[tris(hydroxymethyl)methyl](meth)acrylamide, N-phenylacrylamide, alkylacrylamide, methacrylamide, poly(ethylene glycol)amine hydrochloride, and combinations thereof.

[0046] The hydroxylamine-functional ethylenically unsaturated monomer can preferably be selected from acrylohydroxamic acid.

[0047] The glycol-functional ethylenically unsaturated monomer can preferably be selected from ethylene glycol methyl ether (meth)acrylate, ethylene glycol phenyl ether (meth)acrylate, di(ethylene glycol) methyl ether (meth)acrylate, tri(ethylene glycol) methyl ether (meth)acrylate, poly(ethylene glycol) methyl ether (meth)acrylate, poly(ethylene glycol) phenyl ether acrylate, poly(ethylene glycol) (meth)acrylate, poly(propylene glycol) (meth)acrylate, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (meth)acrylate, polyglycol partial ester monomer, and combinations thereof.

[0048] More preferably, monomer (a2) and / or optionally present monomer (d) contains a monomer of the general formula R 1 C(=CH2)R 2 X, where R 1 is H, methyl or ethyl, R 2 is an arbitrary spacer group of straight-chain or branched having 1 to 5 carbon atoms, X is a functional group of carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate, more preferably R 1 is H or methyl, X is a carboxylic acid, and even more preferably monomer (a2) and / or (d) contains acrylic acid or methacrylic acid, and most preferably monomer (a2) and / or (d) contains methacrylic acid.

[0049] Monomer (b) can include monomers having a total of 3 to 10 carbon atoms and combinations thereof. Such monomers can include acrylonitrile, methacrylonitrile, fumaronitrile, butyronitrile, and combinations thereof, preferably acrylonitrile and / or methacrylonitrile, and more preferably can include acrylonitrile.

[0050] Monomer (b) can be present in the mixture of compounds in an amount of 15 to 60 parts by weight, preferably 20 to 50 parts by weight, based on the weight of the mixture of compounds. Thus, the lower limit of the amount of monomer (b) can be 15, 16, 17, 18, 19, or 20 parts by weight based on the weight of the mixture of compounds. The upper limit of this amount can be 60, 59, 58, 57, 56, 55, 54, 53, 52, or 51 parts by weight based on the weight of the mixture of compounds. Those skilled in the art will understand that any range formed by any of the explicitly disclosed lower and upper limits is explicitly included herein.

[0051] Monomer (c) can include 1,3-butadiene, isoprene, 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-1,3,6-octatriene, 2-methyl-6-methylene-1,7-octadiene, 7-methyl-3-methylene-1,6-octadiene, 1,3,7-octatriene, 2-ethyl-1,3-butadiene, 2-amyl-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-dodecatetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, 2,6-dimethyl-2,4,6-octatriene, 2-phenyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, 1,3-cyclohexadiene, myrcene, ocimene, farnesene, or a combination thereof. Preferably, monomer (c) includes 1,3-butadiene, isoprene, or a combination thereof. More preferably, monomer (c) includes 1,3-butadiene.

[0052] Monomer (c) can be present in the mixture of compounds in an amount of 40 to 90 parts by weight, preferably 50 to 80 parts by weight, based on the weight of the mixture of compounds. Thus, the lower limit of the amount of monomer (c) can be 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50 parts by weight based on the weight of the mixture of compounds. The upper limit of this amount can be 90, 89, 88, 87, 86, 85, 84, 83, 82, 81 or 80 parts by weight based on the weight of the mixture of compounds. Those skilled in the art will understand that any range formed by any of the explicitly disclosed lower and upper limits is explicitly included herein.

[0053] The amounts of the macro-RAFT agent (a) and monomers (b), (c) and (d) when present can total 100 parts by weight based on the weight of the mixture of compounds.

[0054] The copolymer according to the present invention can include sections. The sections according to the present invention can be regions within the copolymer. These sections can have an X-Y structure or an X-Y-Z structure. The sections according to the present invention can have a random structure in which the respective monomer residues are randomly distributed within each section, or a block structure in which the respective monomer residues are distributed in the form of at least two blocks, preferably two or three blocks. Thus, those skilled in the art will recognize that the polymer as a whole does not necessarily have to be a block copolymer, but the polymer may include sections having a block structure, i.e., regions within its structure.

[0055] Section X and, when present, section Z can include monomer (a2) and / or (d), and preferably, sections X and Z do not include monomers (b) and (c).

[0056] Section Y can have a random structure or a block structure including monomers (b) and (c), and optionally, section Y further includes monomer (a2) and / or (d).

[0057] Monomer (d) can be present in an amount of 0 to 20 parts by weight, preferably 0 to 15 parts by weight, more preferably 0 to 10 parts by weight, based on the weight of the mixture of compounds. This includes, in particular, 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 parts by weight based on the weight of the mixture of compounds. Those skilled in the art will understand that any range formed by any of the explicitly disclosed values is explicitly encompassed herein. Since the amount of monomer (d) can be 0 parts by weight based on the weight of the mixture of compounds, those skilled in the art will understand that the mixture of compounds may not contain monomer (d).

[0058] The polymer latex may further contain at least one surfactant. Alternatively, the polymer latex may be a polymer latex that does not contain a surfactant. Those skilled in the art will understand that, despite efforts to not add a surfactant to the mixture of compounds or the resulting polymer latex, trace amounts of surfactant may be present in the surfactant-free polymer latex.

[0059] Accordingly, a surfactant-free polymer latex may contain 0 to 0.05 parts by weight, preferably 0 to 0.005 parts by weight, of one or more surfactants, based on 100 parts by weight of the polymer latex.

[0060] When one or more surfactants are used, surfactants or emulsifiers suitable for stabilizing the polymer dispersion can include conventional surfactants for the polymerization process. The surfactant can be added to the aqueous phase and / or the monomer phase. The effective amount of surfactant in the seed method is the amount selected to support the stabilization of the particles as a colloid, minimize contact between the particles, and prevent aggregation. In the non-seed method, the effective amount of surfactant is the amount selected to determine the particle size.

[0061] Representative surfactants include saturated and ethylenically unsaturated sulfonic acids or their salts, for example, unsaturated hydrocarbon sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid and their salts; aromatic hydrocarbon acids such as p-styrenesulfonic acid, isopropenylbenzenesulfonic acid, vinyloxybenzenesulfonic acid and their salts; sulfoalkyl esters of acrylic acid and methacrylic acid, for example, sulfopropyl methacrylate and sulfopropyl methacrylate and their salts, and 2-acrylamido-2-methylpropanesulfonic acid and its salts; alkylated diphenyloxide disulfonates, C10-13 alkylbenzenesulfonates, sodium dodecylbenzenesulfonate, sulfonated naphthalene formaldehyde condensates, dihexyl or dioctyl esters of sodium sulfosuccinate, sodium alkyl esters of sulfonic acid, ethoxylated alkylphenols, and ethoxylated alcohols; and fatty alcohol sulfates, fatty alcohol (poly)ether sulfates, and mixtures thereof. In many cases, the surfactants are mixed and used in the polymerization, and these are preferably C 10 -C 13 chain length alkylbenzenesulfonate, which can be branched or straight-chain.

[0062] The type and amount of surfactant are typically determined by the number of particles, their size, and their composition. Thus, at least one surfactant can be used in an amount of less than 5 parts by weight, preferably less than 3.5 parts by weight, more preferably less than 3 parts by weight, even more preferably less than 2.5 parts by weight, and most preferably less than 0.9 parts by weight, based on the total weight of the polymer latex. The lower limit of the amount of surfactant can be at least 0.4 parts by weight, preferably at least 0.5 parts by weight, more preferably at least 0.6 parts by weight, even more preferably at least 0.7 parts by weight, and most preferably at least 0.8 parts by weight, based on the total weight of the polymer latex. Thus, the amount of surfactant can range from 0.4 to 5 parts by weight, preferably from 0.5 to 3.5 parts by weight, more preferably from 0.6 to 3 parts by weight, even more preferably from 0.7 to 2.5 parts by weight, and most preferably from 0.8 to 0.9 parts by weight, based on the total weight of the polymer latex. The amount of surfactant includes all values and sub-values therebetween, and includes in particular 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 parts by weight, based on the total weight of the polymer latex.

[0063] When the polymer latex is obtained by free radical polymerization of a mixture of compounds further containing monomer (d), it is particularly preferred that the polymer latex contains at least one surfactant and the at least one surfactant is present in the above amount.

[0064] According to the present invention, the polymer latex can have a median particle size of at least 50 nm, preferably at least 60 nm, more preferably at least 70 nm. The polymer latex can have a median particle size of 200 nm or less, for example 180 nm or less, or 160 nm or less. Those skilled in the art will understand that any range between either the explicitly disclosed lower and upper limits is disclosed herein. Thus, the polymer latex can have a median particle size in the range of 50 nm to 200 nm, preferably 60 nm to 180 nm, more preferably 70 nm to 160 nm. The median particle size can be measured by a dynamic light scattering method according to ISO 22412:2017, for example using a dynamic light scattering device, Mastersizer 2000 (manufactured by Malvern Panalytical, UK).

[0065] Method for Producing Polymer Latex of the Present Invention As described above, according to the present invention, a method for producing a polymer latex containing a copolymer includes the following steps: (1) Obtaining a macro-RAFT agent (a) by free radical polymerization of a RAFT agent (a1) and an ethylenically unsaturated monomer (a2) having at least one functional group of an acid, hydroxyl, ester, amine and / or amide; (2) Obtaining a polymer latex by RAFT-mediated emulsion polymerization of a mixture of compounds containing the following components: (a) The macro-RAFT agent (a) obtained in step (1); (b) An ethylenically unsaturated monomer having a nitrile functional group, and (c) A conjugated diene monomer.

[0066] In the emulsion polymerization for preparing the polymer latex of the present invention, a seed dispersion can be used. Any dispersion seed particles known to those skilled in the art can be used. However, the method of the present invention does not necessarily require seed particles to obtain the polymer latex of the present invention. Therefore, it is preferred not to add a seeding agent before, during or after steps (1) and (2).

[0067] When seed particles are used, the seed particles are preferably present in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total ethylenically unsaturated monomer used in the polymer. Thus, the lower limit of the amount of seed particles can 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 the above amount can 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 of the explicitly disclosed lower and upper limits is explicitly included herein.

[0068] The method according to the present invention can further include a step of shortstopping the polymerization. This may be desirable to control the molecular weight of the resulting copolymer and thus the physical properties. Shortstopping can usually be initiated by adding an appropriate amount of a shortstopping agent. Those skilled in the art will recognize that the shortstopping agent inhibits the formation of radicals by the activator and the growth of polymer chains. Thus, free radical polymerization is stopped by the destruction of the initiator, by the prevention of growth, or by the termination of growing alkyl radicals. Suitable shortstopping agents can be selected to act on all three mechanisms.

[0069] Shortstopping can be initiated when at least 50% conversion has occurred, based on the desired properties of the polymer latex.

[0070] The method for producing the above polymer latex can be carried out at a temperature of 5 to 95 °C, preferably 15 to 80 °C, particularly preferably 30 to 60 °C, preferably in the presence or absence of one or more emulsifiers, in the presence or absence of one or more protective colloids, and in the presence of one or more initiators. The temperature includes 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 °C. The temperature may be changed or remain constant during the polymerization process. When the temperature changes, the temperature can be increased or decreased as long as it remains within the above-defined temperature range between the start and end of the reaction or a short-time stop.

[0071] The initiator that can be used when implementing the present invention can include water-soluble and / or oil-soluble initiators effective for the purpose of polymerization. Representative initiators are well-known in the art and include, for example, azo compounds (such as azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 4,4'-azobis(4-cyanopentanoic acid) (ACPA), and cyano valeric acid, etc.), inorganic peroxide compounds (such as hydrogen peroxide, sodium peroxydisulfate, potassium peroxydisulfate, ammonium peroxydisulfate, peroxydicarbonate, and peroxyborate), organic peroxide compounds (such as alkyl hydroperoxide, dialkyl peroxide, acyl hydroperoxide, and diacyl peroxide), esters (such as tert-butyl perbenzoate), and combinations of inorganic initiators and organic initiators. Suitable initiators include 2,3-dimethyl-2,3-diphenylbutane, tert-butyl hydroperoxide, tert-amyl hydroperoxide, cumyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, isopropylcumyl hydroperoxide, p-menthane hydroperoxide, 2,5-di(tert-butylperoxy)-2,5-dimethyl-3-hexyne, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, di(tert-butyl) peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di(tert-butylperoxyisopropyl)benzene, tert-butylcumyl peroxide, di-(tert-amyl)-peroxide, dicumyl peroxide, butyl 4,4-di(tert-butylperoxy)valerate, tert-butyl peroxybenzoate, butyl 4,4-di(tert-butylperoxy)valerate, tert-butyl peroxybenzoate, 2,2-di(tert-butylperoxy)butane, tert-amyl peroxybenzoate, tert-butyl peroxyacetate, tert-butyl peroxy-(2-ethylhexyl) carbonate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-3,5,5-trimethyl-hexanoate, 1,It can be selected from 1-di(tert-butylperoxy)cyclohexane, tert-amyl peroxyacetate, tert-amyl peroxy-(2-ethylhexyl) carbonate, 1,1-di(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-di(tert-amylperoxy)cyclohexane, tert-butyl monoperoxy-maleate, 1,1'-azodi(hexahydrobenzonitrile), tert-butyl peroxyisobutyrate, tert-butyl peroxy diethylacetate, tert-butyl peroxy-2-ethylhexanoate, dibenzoyl peroxide, tert-amyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, ammonium peroxodisulfate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 2,2'-azodi(2-methylbutyronitrile), 2,2'-azodi(isobutyronitrile), didecanoyl peroxide, potassium persulfate, dilauroyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, tert-amyl peroxypivalate, tert-butyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxypivalate, tert-butyl peroxypivalate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, tert-butyl peroxyneodecanoate, di-sec-butyl peroxydicarbonate, tert-amyl peroxyneodecanoate, cumyl peroxyneopentanoate, di(3-methoxybutyl) peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, cumyl peroxyneodecanoate, diisobutyryl peroxide, and mixtures thereof.,

[0072] The initiator can be used in an amount sufficient to initiate the polymerization reaction at a desired rate. Generally, based on the total weight of compounds (a), (b), and (c) in the mixture of compounds, an amount of initiator of 0.01 to 5% by weight, preferably 0.1 to 4% by weight, is sufficient. Most preferably, the amount of initiator is 0.01 to 2% by weight based on the total weight of compounds (a), (b), and (c) in the mixture of compounds. The amount of initiator includes all values and sub - values therebetween, and particularly includes 0.01, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 4, and 4.5% by weight based on the total weight of compounds (a), (b), and (c) in the mixture of compounds.

[0073] The above - mentioned inorganic peroxide compounds and organic peroxide compounds can also be used alone or in combination with one or more suitable reducing agents, as is well - known in the art. Examples of such reducing agents include sulfur dioxide, alkali metal disulfites, hydrogen sulfites of alkali metals and ammonium, thiosulfates, dithionites, and formaldehyde sulfoxylate, hydroxylamine hydrochloride, hydrazine sulfate, iron(II) sulfate, copper naphthenate, glucose, sulfonic acid compounds such as sodium methanesulfonate, amine compounds such as dimethylaniline, and ascorbic acid. The amount of the reducing agent is preferably 0.03 to 10 parts by weight per part by weight of the polymerization initiator.

[0074] As described above, the polymer latex of the present invention may or may not contain a surfactant. Therefore, in order to obtain a polymer latex without a surfactant, it is preferable not to add a surfactant before, during, or after steps (1) and (2).

[0075] The polymer latex of the present invention may further contain a protective colloid. The protective colloid can stabilize the polymer latex in addition to or instead of the above-mentioned surfactant. The protective colloid may be present during polymerization or may be added later. The protective colloid can include polyvinyl alcohol, vinyl alcohol-ethylene copolymer, silanol-modified polyvinyl alcohol, cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxy cellulose and carboxy cellulose, chitin, chitosan, starch, polyethylene glycol, polypropylene glycol, polyvinyl ether, gelatin, casein, cyclodextrin, and combinations thereof. A typical amount can be 1 to 15 parts by weight based on 100 parts by weight of the polymer latex.

[0076] According to the present invention, the polymerization process can be carried out in any variation known in the art, and in particular, monomers (b), (c) and (d) can be charged by batch, semi-batch, continuous charging method, split charging or split injection. Those skilled in the art will understand that these variations differ depending on how and when these specific monomers are added to the mixture of compounds during the process.

[0077] By these different method variations in combination with the use of the macro-RAFT agent (a) of the present invention, those skilled in the art can prepare a polymer latex containing a copolymer having a predetermined monomer distribution and thus predetermined properties according to the intended use of each obtained polymer latex.

[0078] The method according to the present invention can further include an additional step of charging additional monomer after charging the total amounts of compounds (a), (b) and (c) into the reactor. Such monomers are preferably reactive with at least the functional groups present in compounds (a), (b) or (c).

[0079] Furthermore, it may be beneficial to further carry out the emulsion polymerization in the presence of a buffering substance and a chelating agent. Suitable substances are, for example, phosphates and pyrophosphates of alkali metals (buffering substances), and alkali metal salts of ethylenediaminetetraacetic acid (EDTA) or hydroxy-2-ethylenediaminetriacetic acid (HEEDTA) as chelating agents. The amounts of the buffering substance and the chelating agent are usually 0.001 to 1.0% by weight, based on the total weight of compounds (a), (b), (c) and (d) if present.

[0080] Furthermore, it may be advantageous to use a chain transfer agent (regulator) in the emulsion polymerization. Typical reagents are, for example, organic sulfur compounds such as thioesters, 2-mercaptoethanol, 3-mercaptopropionic acid and C1-C12 alkyl mercaptans, with n-dodecyl mercaptan and t-dodecyl mercaptan being preferred. The amount of the chain transfer agent, if present, is usually 0.05 to 3.0% by weight, preferably 0.2 to 2.0% by weight, based on the total weight of compounds (a), (b), (c) and (d) if present in the mixture of compounds.

[0081] The polymerization process according to the present invention can be carried out under mechanical stirring, i.e., with stirring, in order to achieve an optimal distribution of the reactants and to assist polymerization-induced self-assembly (PISA). The stirring speed is advantageously 80 to 400 rpm, preferably 100 to 350 rpm, or may be as low as about 50 rpm depending on the reactor design.

[0082] Furthermore, it may be beneficial to introduce partial neutralization into the polymerization process. Those skilled in the art will understand that the necessary control can be achieved by an appropriate selection of this parameter.

[0083] To prepare the polymer latex of the present invention, various other additives and components can be added. Such additives include, for example, defoamers, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, fluorescent brighteners, crosslinking agents, accelerators, antioxidants, biocides and metal chelating agents. Known defoamers include silicone oil and acetylene glycol. Commonly known wetting agents include alkylphenol ethoxylates, alkali metal dialkyl sulfosuccinates, acetylene glycol and alkali metal alkyl sulfates. Typical thickeners include polyacrylates, polyacrylamides, xanthan gum, modified cellulose or particulate thickeners (such as silica and clay). Typical plasticizers include mineral oil, liquid polybutene, liquid polyacrylate and lanolin. Zinc oxide is a suitable crosslinking agent. Titanium dioxide (TiO2), calcium carbonate and clay are typically used fillers. Known accelerators and secondary 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), dipentamethylenethiuram hexasulfide (DPTT)), and amines (such as diphenylguanidine (DPG), di-o-tolylguanidine (DOTG), o-tolylbiguanidine (OTBG)).

[0084] Rubber Articles Polymer latex is particularly useful for the manufacture of rubber articles. Accordingly, the present invention also relates to the use of the polymer latex according to the present invention for the manufacture of rubber articles and to rubber articles prepared from the polymer latex according to the present invention. Such rubber articles can include surgical gloves, examination gloves, condoms, catheters, industrial gloves, cloth-supported gloves, household gloves, balloons, tubes, dental dams, aprons, and pre-formed gaskets. Such rubber articles can be prepared using techniques generally known in the art, including, for example, dip molding.

Examples

[0085] The following examples are intended to further illustrate the present invention but are in no way intended to limit the scope of the present invention.

[0086] In the following, all parts and percentages are by weight unless otherwise specified.

[0087] Synthesis of Macro-RAFT Polymer (Macro-RAFT) Example A RAFT agent, 4-((((2-carboxyethyl)thio)-carbonothioyl)thio)-4-cyanopentanoic acid (BM1433, with boron molecules), and an activator were charged into a 250 mL or 2000 mL reactor equipped with a mechanical anchor stirrer, a nitrogen inlet, and a temperature control system, together with deionized water, at a molar ratio of RAFT agent to activator of 1:0.1. The mixture was stirred and bubbled with nitrogen for 20 minutes. Then, the temperature of the mixture was raised to 60 °C, and the pre-degassed monomer was added to the reactor at a fixed molar ratio of RAFT agent to monomer, and then the temperature was immediately raised to 80 °C. The solution quickly turned yellow and all the materials were solubilized. The temperature and stirring were maintained for 2 - 4 hours to obtain a macro-RAFT polymer with a yield of at least 95.0%. For examples of the synthesized macro-RAFT polymers, the molar ratio of the RAFT agent to the monomers and activator used, the types of monomers and activator used, and their target molecular weight (Mw) are shown in Table 1.

[0088]

Table 1

[0089] Synthesis of Carboxylated Nitrile Butadiene (XNBR) Latex Using Macro-RAFT Polymer

[0090] Example 1 3.0 parts of macro-RAFT Example 3, 33 parts of 0.5 M aqueous solution of sodium hydroxide (NaOH), 0.0012 parts of sodium ethylenediaminetetraacetate (Na4EDTA) and 117.1 parts of water were added to the reactor and preheated to 30 °C. Subsequently, 31.0 parts of acrylonitrile (ACN) were charged into the reactor together with 0.05 parts of an activator, cumene hydroperoxide (CHP). The reactor was placed under vacuum and refilled with nitrogen six times to remove oxygen. Then, 66.0 parts of butadiene (BD) were added to the reactor. The temperature of the mixture was maintained at 30 °C and stirred at 350 rpm. Finally, 0.03 parts of aqueous sodium formaldehyde sulfoxylate (SFS) solution was added to the reactor to initiate the reaction. Samples were taken during the polymerization and the conversion was tracked. When the conversion was close to 100%, the reactor was cooled to room temperature. To remove the residual monomer, the reactor was placed under vacuum and nitrogen was passed through for 1 hour.

[0091] Example 2 2.0 parts of macro-RAFT Example 3, 22 parts of 0.5 M aqueous solution of NaOH, 0.0012 parts of Na4EDTA and 128.0 parts of water were added to the reactor and preheated to 30 °C. Subsequently, 31.3 parts of ACN were charged into the reactor together with 0.05 parts of the activator CHP. The reactor was placed under vacuum and refilled with nitrogen six times to remove oxygen. Then, 66.7 parts of BD were added to the reactor. The mixture was maintained at 30 °C and stirred at 350 rpm. Finally, 0.03 parts of aqueous SFS solution was added to the reactor to initiate the reaction. Samples were taken during the polymerization and the conversion was tracked. When the conversion was close to 100%, the reactor was cooled to room temperature. To remove the residual monomer, the reactor was placed under vacuum and nitrogen was passed through for 1 hour.

[0092] Example 3 The procedure was the same as in Example 2, except that 0.6 part of tertiary decyl mercaptan (tDM) was added to the reactor together with ACN.

[0093] Example 4 5.8 parts of macro-RAFT Example 5, 28.5 parts of 0.5 M aqueous solution of NaOH, 0.0012 part of Na4EDTA and 121.6 parts of water were added to the reactor and preheated to 30 °C. Subsequently, 30.1 parts of ACN were charged into the reactor together with 0.05 part of the activator CHP. The reactor was placed under vacuum and refilled with nitrogen six times to remove oxygen. Then, 64.1 parts of BD were added to the reactor. The mixture was heated at 30 °C and stirred at 350 rpm. Finally, 0.03 part of SFS aqueous solution was added to the reactor to initiate the reaction. Samples were taken during the polymerization and the conversion was monitored. When the conversion was close to 100%, the reactor was cooled to room temperature. To remove the residual monomer, the reactor was placed under vacuum and nitrogen was passed through for 1 hour.

[0094] Example 5 3.0 parts of macro-RAFT Example 1, 36.0 parts of 0.5 M aqueous solution of sodium hydroxide, 0.0024 part of Na4EDTA and 114.2 parts of water were added to the reactor and preheated to 30 °C. Subsequently, 31 parts of ACN were charged into the reactor together with 0.09 part of the activator CHP. The reactor was placed under vacuum and refilled with nitrogen six times to remove oxygen. Then, 66.0 parts of BD were added to the reactor. The mixture was heated at 30 °C and stirred at 350 rpm. Finally, 0.05 part of SFS aqueous solution was added to the reactor to initiate the reaction. Samples were taken during the polymerization and the conversion was monitored. When the conversion was close to 100%, the reactor was cooled to room temperature. To remove the residual monomer, the reactor was placed under vacuum and nitrogen was passed through for 1 hour.

[0095] Example 6 3.0 parts by weight of macro-RAFT Example 2 and 0.67 parts by weight of a 5% aqueous solution of NaOH (NaOH 5%) were added to a reaction vessel and preheated to 30°C. Subsequently, while maintaining the temperature and stirring at 30°C and 150 rpm, respectively, the monomers (31.0 parts by weight of ACN and 66.0 parts by weight of BD) were charged into the reactor together with 0.6 parts by weight of tDM, and then 0.01 parts by weight of Na4EDTA, the co-activator, 0.0262 parts by weight of SFS dissolved in 4 parts of water, and 0.0474 parts by weight of the activator CHP were added to the reaction vessel that had been purged with nitrogen three times.

[0096] An additional 0.0474 parts by weight of CHP was added after 6 hours, and 0.0262 parts by weight of SFS was added after 7 hours. Then, the temperature was raised to 45°C after 8 hours and then raised again to 60°C after 9 hours and maintained until 95% conversion was achieved to obtain 40% total solids. The polymerization was stopped briefly by adding 0.0474 parts by weight of isopropylhydroxylamine, IPHA.

[0097] The pH was adjusted to pH 7.0 using a 5% aqueous solution of potassium hydroxide (KOH 5%), and the residual monomers were removed by vacuum distillation at 60°C for at least 8 hours. Next, 0.5 parts by weight of Wingstay L type antioxidant (60% dispersion in water) was added to the raw latex, and KOH 5% was added to adjust the pH to 8.0 again. Here, all parts added were based on the total solids.

[0098] Example 7 3.0 parts by weight of macro-RAFT Example 2 and 0.67 parts by weight of 5% NaOH were added to the reaction vessel and preheated to 30 °C while stirring at 150 rpm. 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 (NaPS) dissolved in 2 parts by weight of water. Next, the monomers (35.0 parts by weight of ACN and 62.0 parts by weight of BD) were added over 6 hours together with 0.6 parts by weight of tDM. At the same time, Bruggolite FF6 was added at a co-activator feed rate of 0.0143 parts by weight per hour. After maintaining the temperature at 30 °C for 8 hours, it was raised to 45 °C and maintained until 95% conversion was achieved, obtaining 40% total solids. The polymerization was stopped briefly by adding 0.0474 parts by weight of isopropylhydroxylamine, IPHA.

[0099] The pH was adjusted to pH 7.0 using 5% KOH and the residual monomers were removed by vacuum distillation at 60 °C. 0.5 parts by weight of Wingstay L antioxidant (60% dispersion in water) was added to the raw latex and the pH was readjusted to 8.0 by adding more 5% KOH. Here, all parts added are based on total solids.

[0100] Example 8 The procedure was the same as in Example 7 except that the reactor temperature was raised and maintained at 45 °C throughout the polymerization.

[0101] Example 9 The procedure was the same as in Example 8 except that 60 parts by weight of BD was used and 2.0 parts by weight of MAA was added over 5 minutes 9 hours later.

[0102] Example 10 The procedure was the same as in Example 8 except that 60 parts by weight of BD was used and 2.0 parts by weight of MAA was fed over 6 hours 5 hours later.

[0103] Example 11 Based on 100 parts by weight of the monomer containing seed latex, 2.0 parts by weight (based on polymer solids) of seed latex (average particle size 36 nm) and 3.0 parts by weight of macro-RAFT Example 2 were added to a nitrogen-purged autoclave, and then heated to 30 °C. Subsequently, 0.01 part by weight of Na4EDTA and 0.005 part by weight of Bruggolite FF6 dissolved in 2 parts by weight of water were added, and then 0.08 part by weight of NaPS dissolved in 2 parts by weight of water was added. Then, the monomer (35.0 parts by weight of ACN, 57.0 parts by weight of BD, 3.0 parts by weight of MAA) was added over 6 hours together with 0.6 part by weight of tDM. Over 10 hours, 2.2 parts by weight of sodium dodecylbenzenesulfonate, 0.2 part by weight of tetrasodium pyrophosphate and 22 parts by weight of water were added. A co-activator feed of 0.10 part by weight of Bruggolite FF6 in 8 parts by weight of water was added over 9 hours. The polymerization temperature started at 30 °C, ended at 60 °C, reached 95% conversion, and 40% total solids were obtained.

[0104] The polymerization was stopped briefly by the addition of 0.08 part by weight of an IPHA solution. The pH was adjusted to pH 7.0 using 5% KOH, and the residual monomer was removed by vacuum distillation at 60 °C. 0.5 part by weight of Wingstay L antioxidant (60% dispersion in water) was added to the raw latex, and the pH was readjusted to 8.0 by the addition of 5% KOH.

[0105] Example 12 The procedure was the same as in Example 11, except that 54.0 parts by weight of BD and 6.0 parts by weight of MAA were used.

[0106] Example 13 The procedure was the same as in Example 11, except that 0.88 part by weight of sodium dodecylbenzenesulfonate was fed over a period of 5 hours.

[0107]

Table 2

Claims

1. Polymer latex containing copolymers obtained by free radical emulsion polymerization of a mixture of compounds containing the following components: (a) A macro-reversible addition-cleavage chain transfer (macro-RAFT) agent, which can be obtained by free radical polymerization of a RAFT agent (a1) and an ethylenically unsaturated monomer (a2) having at least one functional group of an acid, hydroxyl, ester, ether, amine, sulfonate and / or amide, (b) Ethylene unsaturated monomers having nitrile functional groups, and (c) Conjugated diene monomer.

2. The polymer latex according to claim 1, wherein the mixture of compounds further comprises (d) an ethylenically unsaturated monomer having at least a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine, or sulfate functional group.

3. The polymer latex according to claim 1 or 2, wherein the RAFT agent (a1) comprises a compound having a thiocarbonyl functional group.

4. The polymer latex according to claim 3, wherein the thiocarbonyl functional group comprises a trithiocarbonate, dithioester, thiocarbamate, and / or xanthate functional group.

5. The polymer latex according to claim 1 or 2, wherein the macro-RAFT agent (a) can induce polymerization-induced self-assembly (PISA).

6. The polymer latex according to claim 1 or 2, wherein monomer (b) comprises a monomer having a total of 3 to 10 carbon atoms or a combination thereof.

7. Monomer (c) is 1,3-butadiene, isoprene, 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-1,3,6-octatriene, 2-methyl-6-methylene-1,7-octadiene, 7-methyl-3-methylene-1,6-octadiene, The polymer latex according to claim 1 or 2, comprising 1,3,7-octatriene, 2-ethyl-1,3-butadiene, 2-amyl-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-dodecatetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, 2,6-dimethyl-2,4,6-octatriene, 2-phenyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, 1,3-cyclohexadiene, myrcene, ocimene, farnacene, or a combination thereof.

8. Monomer (a2) and / or (d) of the general formula R １ C (=CH ２ ) R ２ The formula contains a monomer of X, where R １ is H, methyl or ethyl, and R ２ The polymer latex according to claim 1 or 2, wherein X is any linear or branched spacer group having 1 to 5 carbon atoms, and X is a functional group of a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine, or sulfate.

9. The polymer latex according to claim 1 or 2, wherein the copolymer comprises sections having an X-Y structure or an X-Y-Z structure.

10. The polymer latex according to claim 9, wherein section Y has a random or block structure comprising monomers (b) and (c), and optionally further comprises monomers (a2) and / or (d).

11. The polymer latex according to claim 9, wherein section X and, if present, section Z, comprises monomer (a2) and / or (d).

12. The polymer latex according to claim 1 or 2, wherein the content of monomer (b) in the compound mixture is 15 to 60 parts by weight, based on the weight of the compound mixture.

13. The polymer latex according to claim 1 or 2, wherein the content of monomer (c) in the compound mixture is 40 to 90 parts by weight, based on the weight of the compound mixture.

14. The polymer latex according to claim 1 or 2, wherein the macro-RAFT agent (a) is present in an amount of 1.5 to 10 parts by weight, based on the weight of the compound mixture.

15. The polymer latex according to claim 2, wherein monomer (d) is present in an amount of 0.5 to 20 parts by weight, based on the weight of the compound mixture.

16. The polymer latex according to claim 1 or 2, further comprising a surfactant, wherein the surfactant content in the polymer latex is less than 5 parts by weight based on the total weight of the polymer latex.

17. A polymer latex according to claim 1 or 2, which does not contain a surfactant.

18. A method for producing a copolymer latex, including the following steps: (1) Obtain a macro-RAFT agent (a) by free radical polymerization of a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, amine, and / or amide functional group. (2) Obtain a polymer latex by RAFT-mediated emulsion polymerization of a mixture of compounds containing the following components, (a) Macro-RAFT agent (a) obtained in step (1), (b) Ethylene unsaturated monomers having nitrile functional groups, and (c) Conjugated diene monomer.

19. The method according to claim 18, further comprising adding to the reaction mixture at least one ethylenically unsaturated monomer (a2) and / or (d) having at least one acid, hydroxyl, ester, amine and / or amide functional group during and / or after step (2).

20. The method according to claim 19, wherein monomers (b), (c), and / or (d) are charged by batch, half-batch, continuous, partial charging, or partial injection.

21. The method according to any one of claims 18 to 20, wherein at least one of the following is satisfied: (i) Ethylene unsaturated monomers (a2) having at least one acid, hydroxyl, ester, amine and / or amide functional group include monomers of the general formula R1C(=CH2)R2X, where R1 is H, methyl or ethyl, R2 is any linear or branched spacer group having 1 to 5 carbon atoms, and X is a functional group of a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate. (ii) Monomer (b) includes monomers having a total of 3 to 10 carbon atoms or combinations thereof. (iii) Monomer (c) is 1,3-butadiene, isoprene, 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-1,3,6-octatriene, 2-methyl-6-methylene-1,7-octadiene, 7-methyl-3-methylene- 1,6-octadiene, 1,3,7-octatriene, 2-ethyl-1,3-butadiene, 2-amyl-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-dodecatetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, 2,6-dimethyl-2,4,6-octatriene, 2-phenyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, 1,3-cyclohexadiene, myrcene, ocimene, farnacene, or combinations thereof, (iv) The monomer (d) is an ethylenically unsaturated monomer having at least a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine, or sulfate functional group. (v) The copolymer comprises sections having an X-Y structure or an X-Y-Z structure.

22. The method according to any one of claims 18 to 20, wherein no surfactant is added before, during, or after steps (1) and (2).

23. The method according to any one of claims 18 to 20, wherein no seeding agent is added before, during, or after steps (1) and (2).

24. The method according to any one of claims 18 to 20, wherein the polymerization in step (2) is carried out at a temperature of 5°C to 95°C.

25. Use of a polymer latex according to claim 1 or 2, or a polymer latex prepared by the method described in any one of claims 18 to 20, for the preparation of rubber articles.

26. The use according to claim 25, wherein the rubber article includes surgical gloves, examination gloves, condoms, catheters, industrial gloves, cloth support gloves, household gloves, balloons, tubes, dental dams, aprons, and pre-formed gaskets.

27. A rubber article prepared from the polymer latex described in claim 1 or 2, or from a polymer latex prepared by the method described in any one of claims 18 to 20.

28. The rubber article according to claim 27, wherein the rubber article includes surgical gloves, examination gloves, condoms, catheters, industrial gloves, cloth support gloves, household gloves, balloons, tubes, dental dams, aprons, and pre-formed gaskets.