XNBR Polymers Formed Using Radical Polymerizers

Abstract

The present invention relates to a polymer latex comprising a copolymer, a process for the preparation of the polymer latex, the use of the polymer latex for the preparation of rubber articles and articles prepared using the polymer latex.

Description

[0001] The present invention relates to a polymer latex, a method for obtaining the polymer latex, and the use of the polymer latex for preparing a rubber product. The present invention also relates to a rubber product prepared from the polymer latex or from the polymer latex prepared by the method. Background Art

[0002] XNBR (carboxylated nitrile rubber) has been known in the art for many years. Such rubbers are usually prepared by free radical emulsion polymerization of butadiene, olefinic unsaturates having nitrile groups and olefinic unsaturates having carboxyl groups.

[0003] However, this method has several disadvantages. First, the monomers present in the obtained rubber are randomly distributed, which does not allow for a specific monomer distribution within the final polymer as a whole, for example where certain monomers should be distributed favorably towards one or both ends of the polymer chain. This problem can be partially overcome by providing block copolymers; however, this method generally requires multiple polymerization steps, which is inefficient and therefore undesirable.

[0004] In addition, conventional emulsion polymerization requires the presence of a surfactant to enable the formation of micelles in which polymerization can occur. However, the presence of a surfactant in the obtained polymer latex generally causes problems during the subsequent production of several rubber products (e.g. nitrile rubber gloves). Therefore, it is necessary to at least partially remove the surfactant from the obtained polymer latex, which requires large amounts of water. In order to produce 1000 gloves, about 300 to 400 liters of water are required.

[0005] Therefore, there is a need to overcome the disadvantages of the methods known in the art both in terms of economic and ecological factors.

[0006] It is therefore an object of the present invention to provide a polymer latex whose monomer distribution can be specifically adjusted and which does not require the necessary presence of surfactants during its production, thereby making the production process more economical and more eco-friendly. Summary of the invention

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

[0008] According to a first aspect, the present invention relates to a polymer latex comprising a copolymer obtainable by free radical emulsion polymerization of a mixture of compounds comprising:

[0009] (a) a macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agent obtainable by free radical polymerization of a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide functional group,

[0010] (b) an ethylenically unsaturated monomer having a nitrile functional group; and

[0011] (c) Conjugated diene monomers.

[0012] The mixture of compounds may further comprise

[0013] (d) ethylenically unsaturated monomers having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide functional group. In particular, compound (d) may be an ethylenically unsaturated monomer having at least one carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate functional group.

[0014] The RAFT agent (a1) may include a compound having a thiocarbonyl functional group.

[0015] The thiocarbonyl functional group may comprise a trithiocarbonate, a dithioester, a thiocarbamate and / or a xanthate functional group.

[0016] The macromolecular RAFT agent (a) may be capable of inducing polymerization induced self-assembly (PISA).

[0017] The monomer (b) may include monomers having a total of 3 to 10 carbon atoms and combinations thereof, preferably acrylonitrile, butyronitrile and combinations thereof, more preferably acrylonitrile.

[0018] Monomer (c) may 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-octadiene, 2,3-diethyl-1,3-butadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, 3,7-dimethyl-1,3,6-octatriene, 2,3-dimethyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-hex ... 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-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 and combinations thereof, preferably 1,3-butadiene, isoprene and combinations thereof, more preferably 1,3-butadiene.

[0019] Monomers (a2) and / or (d) may contain a compound of the general formula R1 C(=CH2)R 2 X monomer, where R 1 is H, methyl or ethyl, R 2 is an optional linear or branched spacer group having 1 to 5 carbon atoms, and X is a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate functional group, preferably R 1 is H or methyl and X is a carboxylic acid, more preferably monomer (a2) and / or (d) comprises acrylic acid or methacrylic acid, most preferably monomer (a2) and / or (d) comprises methacrylic acid.

[0020] The copolymer may contain components having an XY structure or an XYZ structure.

[0021] Component Y can have a random or block structure comprising monomers (b) and (c), wherein optionally component Y also comprises monomers (a2) and / or (d).

[0022] Component X and component Z (if present) may comprise monomers (a2) and / or (d), preferably components X and Z are free of monomers (b) and (c).

[0023] The content of the monomer (b) in the compound mixture may be 15 to 60 parts by weight, preferably 20 to 50 parts by weight, based on the weight of the compound mixture.

[0024] The content of the monomer (c) in the compound mixture may be 40 to 90 parts by weight, preferably 50 to 80 parts by weight, based on the weight of the compound mixture.

[0025] The macro RAFT agent (a) may 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 compound mixture.

[0026] The monomer (d) may 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.

[0027] The polymer latex may further comprise a surfactant, wherein the surfactant content in the polymer latex may 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.

[0028] The polymer latex may be a surfactant-free polymer latex.

[0029] According to a second aspect, the present invention relates to a method for preparing a polymer latex comprising a block copolymer, the method comprising the following steps:

[0030] (1) free radically polymerizing a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide functional group to receive a macromolecular RAFT agent (a),

[0031] (2) RAFT-mediated emulsion polymerization of a mixture of compounds to obtain the polymer latex, the mixture of compounds comprising:

[0032] (a) the macromolecular RAFT agent (a) received in step (1);

[0033] (b) an ethylenically unsaturated monomer having a nitrile functional group; and

[0034] (c) Conjugated diene monomers.

[0035] The method may further comprise adding at least one ethylenically unsaturated monomer (a2) and / or (d) having at least one acid, hydroxyl, ester, amine and / or amide functional group to the reaction mixture during and / or after step (2), preferably wherein monomers (a2) and / or (d) are ethylenically unsaturated monomers having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide functional group, more preferably wherein monomers (a2) and (d) comprise a monomer of the general formula R 1 C(=CH2)R 2 X monomer, where R 1 is H, methyl or ethyl, R 2 is an optional linear or branched spacer group having 1 to 5 carbon atoms, and X is a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate functional group, preferably R 1 is H or methyl and X is a carboxylic acid, more preferably monomer (a2) and / or (d) comprises acrylic acid or methacrylic acid, most preferably monomer (a2) and / or (d) comprises methacrylic acid.

[0036] The monomers (b), (c) and (d) may be added by batch addition, semi-batch addition, continuous addition, or batch injection.

[0037] According to the second aspect, at least one of the following may be satisfied:

[0038] (i) ethylenically unsaturated monomers having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide functional group (a2) include monomers as defined above;

[0039] (ii) monomer (b) is a monomer as defined above;

[0040] (iii) monomer (c) is a monomer as defined above;

[0041] (iv) Monomer (d) is an ethylenically unsaturated monomer having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide functional group, preferably a monomer of the general formula R 1 C(=CH2)R 2 X monomer, where R 1 is H, methyl or ethyl, R 2 is an optional linear or branched spacer group having 1 to 5 carbon atoms, and X is a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate functional group, preferably R 1 is H or methyl and X is a carboxylic acid, more preferably monomer (d) comprises acrylic acid or methacrylic acid, most preferably monomer (d) comprises methacrylic acid; and / or

[0042] (v) The copolymer comprises the components as defined above.

[0043] According to the second aspect, no surfactant may be added before, during or after steps (1) and (2).

[0044] According to the second aspect, no inoculant may be added before, during or after steps (1) and (2).

[0045] The polymerization of step (2) can be carried out at a temperature of 5°C to 95°C, preferably 30°C to 60°C.

[0046] In a third aspect, the present invention relates to use of the polymer latex according to any item of the first aspect or the polymer latex prepared by the method according to any item of the second aspect for preparing a rubber product.

[0047] Rubber products may include surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-backed gloves, household gloves, balloons, tubing, dental aprons, aprons, and preformed gaskets.

[0048] In a fourth aspect, the present invention relates to a rubber article prepared from a polymer latex according to any clause of the first aspect or from a polymer latex prepared by a method according to any clause of the second aspect.

[0049] Rubber products may include surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-backed gloves, household gloves, balloons, tubing, dental aprons, aprons, and preformed gaskets. DETAILED DESCRIPTION OF THE INVENTION

[0051] The present invention relates to a polymer latex which can be used to produce rubber products. The polymer latex comprises a copolymer which can be obtained by free radical emulsion polymerization of a mixture of compounds. The mixture of compounds comprises (a) a macromolecular reversible addition-fragmentation chain transfer (macromolecular RAFT) agent, (b) an ethylenically unsaturated monomer having a nitrile functional group, and (c) a conjugated diene monomer. The macromolecular 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 acid, hydroxyl, ester, ether, sulfonate and / or amide functional group. The mixture of compounds preferably also comprises (d) an ethylenically unsaturated monomer having at least one acid, hydroxyl, ester, ether, sulfonate and / or amide functional group.

[0052] Surprisingly, it has been found that by using a macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agent (a) as an additional component during the production of a polymer latex by free radical emulsion polymerization, a stable polymer latex can be obtained, despite the presence of only a smaller amount of surfactant, or even no surfactant, in the mixture of compounds during the polymerization compared to conventional emulsion polymerization due to polymerization induced self-assembly (PISA). Another benefit 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 regulated according to the amount and time of adding the corresponding monomers to the mixture of compounds during the polymerization process.

[0053] The macro RAFT agent (a) is obtainable by free radical polymerization of a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, ether, sulfonate and / or amide function.

[0054] The macromolecular RAFT agent (a) may have an Mw of at least 500 g / mol, preferably 750 g / mol, more preferably 1000 g / mol and not more than 5000 g / mol, preferably 4750 g / mol, more preferably 4500 g / mol. It will be appreciated by those skilled in the art that any range formed by any explicitly disclosed lower and upper limits is expressly encompassed in this specification. Thus, the macromolecular RAFT agent (a) may particularly have an Mw of 500 g / mol to 5000 g / mol, preferably 750 g / mol to 4750 g / mol, more preferably 1000 g / mol to 4500 g / mol. It will be appreciated by those skilled in the art that Mw may be measured using techniques generally known in the art, including size exclusion chromatography and mass spectrometry using suitable standards.

[0055] Based on the weight of the mixture of compounds, the macromolecular RAFT agent (a) can be present in the mixture of compounds in an amount of 1 to 10 parts by weight, preferably 1.75 to 8 parts by weight, and more preferably 2 to 6 parts by weight. Therefore, based on the weight of the mixture of compounds, the lower limit of the amount of the macromolecular RAFT agent (a) can be 1 part by weight, 1.50 parts by weight, 1.55 parts by weight, 1.60 parts by weight, 1.65 parts by weight, 1.70 parts by weight, 1.75 parts by weight, 1.80 parts by weight, 1.85 parts by weight, 1.90 parts by weight, 1.95 parts by weight or 2.0 parts by weight. Based on the weight of the mixture of compounds, the upper limit of the amount can be 10 parts by weight, 9.5 parts by weight, 9 parts by weight, 8.5 parts by weight, 8 parts by weight, 7.5 parts by weight, 7 parts by weight, 6.5 parts by weight or 6 parts by weight. It will be understood by those skilled in the art that any range formed by any explicitly disclosed lower and upper limits is explicitly included in this specification.

[0056] The RAFT agent (a1) may comprise a compound having a thiocarbonyl functional group. Preferably, the thiocarbonyl functional group may comprise a trithiocarbonate, a dithioester, a thiocarbamate and / or a xanthate functional group. Commercially available examples of RAFT agents (a1) include, for example, 4-((((2-carboxyethyl)thio)thiocarbonyl)thio)-4-cyanovaleric acid, 4-((((2-carboxyethyl)thio)thiocarbonyl)thio)-4-acetamidopentanoic acid, 2,2'-[thiocarbonylbis(thio)]bis[2-methylpropionic acid], 3-((((1-carboxyethyl)thio)thiocarbonyl)thio)propionic acid, bis(dodecylsulfanylthiocarbonyl)disulfide, (3,5-dimethyl-1H-pyrazole)-dithiocarboxylic acid cyanomethyl ester and dibenzyl trithiocarbonate; however, those skilled in the art will appreciate that any RAFT agent may be suitable for obtaining the polymer latex according to the present invention.

[0057] Monomer (a2) and / or optionally present monomer (d) may be identical or different monomers. These monomers may preferably be selected from ethylenically unsaturated acids and salts thereof, hydroxyl-functional ethylenically unsaturated monomers, ethylenically unsaturated monomers with primary or secondary amino groups, ethylenically unsaturated monomers with amide groups, hydroxylamine-functional ethylenically unsaturated monomers, diol-functional ethylenically unsaturated monomers and combinations thereof.

[0058] The ethylenically unsaturated acid and its salt can be preferably selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, ethylenically unsaturated sulfonic acid, ethylenically unsaturated phosphorus acid and its salt, polycarboxylic acid anhydride, polycarboxylic acid partial ester monomer, carboxyalkyl ester of ethylenically unsaturated acid and combination thereof.

[0059] The hydroxy-functional ethylenically unsaturated monomer may 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.

[0060] The ethylenically unsaturated monomers having a primary amino group, a secondary amino group and / or an amide group may 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-(methacrylamido)propyl]trimethylammonium salt, N-[tris (hydroxymethyl)methyl] (meth)acrylamide, N-phenylacrylamide, alkyl acrylamide, methacrylamide, poly (ethylene glycol) amine hydrochloride and combinations thereof.

[0061] The hydroxylamine functional ethylenically unsaturated monomer may preferably be acrylic hydroxamic acid.

[0062] The diol-functional ethylenically unsaturated monomer may 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 monomers and combinations thereof.

[0063] More preferably, monomer (a2) and / or optionally present monomer (d) comprises the general formula R 1 C(=CH2)R 2 X monomer, where R 1 is H, methyl or ethyl, R 2 is an optional linear or branched spacer group having 1 to 5 carbon atoms, and X is a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate functional group, more preferably R 1 is H or methyl and X is a carboxylic acid, even more preferably monomer (a2) and / or (d) comprises acrylic acid or methacrylic acid, most preferably monomer (a2) and / or (d) comprises methacrylic acid.

[0064] Monomer (b) may include monomers having a total of 3 to 10 carbon atoms and combinations thereof. Such monomers may include acrylonitrile, methacrylonitrile, fumaronitrile, butyronitrile and combinations thereof, preferably acrylonitrile and / or methacrylonitrile, more preferably acrylonitrile.

[0065] Based on the weight of the mixture of compounds, monomer (b) can be present in the mixture of compounds with 15 to 60 parts by weight, preferably 20 to 50 parts by weight. Therefore, 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. Based on the weight of the mixture of compounds, the upper limit of the amount can be 60,59,58,57,56,55,54,53,52 or 51 parts by weight. It will be understood by those skilled in the art that any scope formed by any clearly disclosed lower limit and upper limit is explicitly included in this specification.

[0066] Monomer (c) may 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-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-dodecatetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecatetraene, 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 and combinations thereof. Preferably, monomer (c) comprises 1,3-butadiene, isoprene and combinations thereof. More preferably, monomer (c) comprises 1,3-butadiene.

[0067] Based on the weight of the mixture of compounds, monomer (c) can be present in the mixture of compounds with 40 to 90 parts by weight, preferably 50 to 80 parts by weight. Therefore, based on the weight of the mixture of compounds, the lower limit of the amount of monomer (c) can be 40,41,42,43,44,45,4,47,48,49 or 50 parts by weight. Based on the weight of the mixture of compounds, the upper limit of the amount can be 90,89,88,87,86,85,84,83,82,81 or 80 parts by weight. It will be understood by those skilled in the art that any scope formed by any clearly disclosed lower limit and upper limit is explicitly included in this specification.

[0068] The amount of macro-RAFT agent (a) and monomers (b), (c) and (d) (if present) may total 100 parts by weight, based on the weight of the mixture of compounds.

[0069] The copolymer according to the present invention may contain components. The components described in the present invention may be regions within the copolymer. These components may have an XY structure or an XYZ structure. The components according to the present invention may have a random structure, wherein the corresponding monomer residues are distributed in a random manner within the corresponding components, or have a block structure, wherein the corresponding monomer residues are distributed in the form of at least two blocks, preferably two or three blocks. Therefore, those skilled in the art will recognize that although the entire polymer may not be a block copolymer completely, the polymer may contain components, i.e., regions within the structure, which have a block structure.

[0070] Components X and Z (if present) may comprise monomers (a2) and / or (d), preferably wherein components X and Z do not contain monomers (b) and (c). Component Y may have a random or block structure comprising monomers (b) and (c), wherein optionally component Y also comprises monomers (a2) and / or (d).

[0071] Based on the weight of the mixture of compounds, 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. This particularly includes 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. It will be understood by those skilled in the art that any range formed by any clearly disclosed value is explicitly included in this specification. Due to the weight based on the mixture of compounds, the amount of monomer (d) can be 0 parts by weight, so it is understood by those skilled in the art that the mixture of compounds may not contain monomer (d).

[0072] The polymer latex may further comprise at least one surfactant. Alternatively, the polymer latex may be a surfactant-free polymer latex. It will be appreciated by those skilled in the art that trace amounts of surfactants may be present in the surfactant-free polymer latex, despite efforts being made not to add any surfactant to the mixture of compounds or the polymer latex obtained.

[0073] Therefore, the 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.

[0074] In the case of using one or more surfactants, the surfactant or emulsifying agent that is suitable for stable polymer dispersions may include those conventional surface-active agents for polymerization process. One or more surfactants can be added in aqueous phase and / or monomer phase. In the seed method, the effective amount of surfactant is selected to support the stabilization of the particle as colloid, minimize the contact between the particles and prevent the amount of coagulation. In non-seed methods, the effective amount of surfactant is selected to determine the amount of particle size.

[0075] Representative surfactants may include saturated and ethylenically unsaturated sulfonic acids or salts thereof, including, for example, unsaturated hydrocarbon sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid and their salts; aromatic hydrocarbon acids, for example, p-styrene sulfonic acid, isopropenylbenzenesulfonic acid and vinyloxybenzenesulfonic 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 its salts; alkylated diphenyl oxide disulfonates, C10-13 alkylbenzenesulfonates, sodium dodecylbenzenesulfonate, sulfonated naphthalene formaldehyde condensates and dihexyl or dioctyl esters of sodium sulfosuccinate, sodium alkyl esters of sulfonic acids, ethoxylated alkylphenols and ethoxylated alcohols; fatty alcohol sulfates, fatty alcohol (poly) ether sulfates and mixtures thereof. Typically, surfactants are used in blends in polymerization, and these are preferably C 10 -C 13 The chain length of the alkylbenzene sulfonate may be branched or linear.

[0076] The type and amount of surfactant are usually determined by the number of particles, their size and their composition. Therefore, based on the gross weight of the polymer latex, at least one surfactant can be used in an amount less than 5 weight parts, preferably less than 3.5 weight parts, more preferably less than 3 weight parts, even more preferably less than 2.5 weight parts and most preferably less than 0.9 weight part. Based on the gross weight of the polymer latex, the lower limit of the amount of surfactant can be at least 0.4 weight part, preferably at least 0.5 weight part, more preferably at least 0.6 weight part, even more preferably at least 0.7 weight part and most preferably at least 0.8 weight part. Therefore, based on the gross weight of the polymer latex, the amount of surfactant can be 0.4 to 5 weight parts, preferably 0.5 to 3.5 weight parts, more preferably 0.6 to 3 weight parts, even more preferably 0.7 to 2.5 weight parts, most preferably 0.8 to 0.9 weight part. The amount of surfactant includes all values ​​and subvalues ​​therebetween, specifically including 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.

[0077] It is particularly preferred that, in case the monomer (d) polymer latex is obtained by free radical polymerization of a mixture of compounds further comprising monomer (d), the polymer latex comprises at least one surfactant, wherein the at least one surfactant is present in an amount as described above.

[0078] According to the present invention, the polymer latex can have a median particle size of at least 50nm, preferably at least 60nm, more preferably at least 70nm. The polymer latex can have a median particle size of not more than 200nm, for example not more than 180nm, or not more than 160nm. It will be appreciated by those skilled in the art that any range between any explicitly disclosed lower and upper limits is disclosed herein. Therefore, the polymer latex can have a median particle size of 50nm to 200nm, preferably 60nm to 180nm, more preferably 70nm to 160nm. The median particle size can be determined by dynamic light scattering according to ISO 22412:2017, for example, using a dynamic light scattering instrument Mastersizer2000 (Malvern Panalytical (UK)).

[0079] Method for preparing polymer latex of the present invention

[0080] As described above, according to the present invention, a method for preparing a polymer latex containing a copolymer comprises the following steps:

[0081] (1) free radically polymerizing a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, amine and / or amide functional group to receive a macromolecular RAFT agent (a),

[0082] (2) RAFT-mediated emulsion polymerization of a mixture of compounds comprising:

[0083] (a) the macromolecular RAFT agent (a) received in step (1);

[0084] (b) an ethylenically unsaturated monomer having a nitrile functional group; and

[0085] (c) a conjugated diene monomer to obtain the polymer latex.

[0086] In the emulsion polymerization for preparing the polymer latex of the present invention, a seed dispersion can be used. Any dispersed 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 that no inoculating agent is added before, during or after steps (1) and (2).

[0087] In the case of using seed particles, the total ethylenically unsaturated monomers used in the polymer based on 100 weight parts, the seed particles are preferably present in an amount of 0.01 to 10 weight parts, preferably 0.1 to 5 weight parts. Therefore, 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 weight parts. The upper limit of this 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 weight parts. One skilled in the art will understand that any range formed by any explicitly disclosed lower and upper limits is expressly encompassed within this specification.

[0088] The method according to the present invention may additionally include the step of arresting the polymerization. This may be desirable in order to control the molecular weight of the resulting copolymer and therefore control the physical properties. Usually the arrest can be caused by adding an appropriate amount of arresting agent. Those skilled in the art will recognize that the arresting agent will inhibit the free radical formation and growth of the polymer chain by the activator. Therefore, the polymerization will be stopped by destroying the initiator, by preventing growth or by the termination of the growing alkyl radicals. Suitable arresting agents can be selected so that they work on all three mechanisms.

[0089] Depending on the desired properties of the polymer latex, shut-down may be initiated when at least 50% conversion has occurred.

[0090] The method for preparing the above-mentioned polymer latex can be carried out at a temperature of 5-95°C, preferably 15-80°C, particularly preferably 30-60°C, preferably in the absence of an emulsifier or in the presence of one or more emulsifiers, in the absence of a protective colloid or in the presence of one or more protective colloids and one or more initiators. The temperature includes all values ​​and subvalues ​​therebetween, especially including 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95°C. During the polymerization process, the temperature can be varied or kept constant. In the case of a temperature variation, the temperature can be increased or decreased as long as it remains within the temperature range defined above between the start and end or shutdown of the reaction.

[0091] Initiators that can be used when carrying out the present invention may 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., azobisisobutyronitrile (AIBN); 2,2'-azobis(2-methylbutyronitrile) (AMBN), 4,4'-azobis(4-cyanovaleric acid) (ACPA) and cyanovaleric acid) and inorganic peroxy compounds such as hydrogen peroxide, sodium peroxodisulfate, potassium peroxodisulfate, ammonium peroxodisulfate, sodium percarbonate, potassium percarbonate, ammonium percarbonate, sodium perborate, potassium perborate, ammonium perborate, and organic peroxy 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.Suitable initiators may be selected from 2,3-dimethyl-2,3-diphenylbutane, tert-butyl hydroperoxide, tert-amyl hydroperoxide, cumyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, isopropyl cumyl 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-triperoxynonane, di(tert-butyl) peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di(tert-butylperoxy-isopropyl)benzene, tert-butyl cumyl peroxide, di-(tert-amyl) )-peroxide, dicumyl peroxide, 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 peroxyisopropylcarbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, 1,1-di(tert-butylperoxy)cyclohexane, tert-amyl peroxyacetate, tert-amyl peroxy-(2-ethylhexyl)carbonate, 1,1-di(tert-butylperoxy)cyclohexane, monoperoxymaleic acid tert-Butyl peroxide, 1,1'-azobis(hexahydrobenzonitrile), tert-Butyl peroxyisobutyrate, tert-Butyl peroxydiethylacetate, 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'-azobis(2-methylbutyronitrile), 2,2'-azobis(isobutyronitrile), didecanoyl peroxide, potassium persulfate, dilauroyl peroxide, di(3,5,5-trimethylhexanoyl)peroxide, neopentyl peroxide tert-amyl valerate, tert-butyl peroxyneoheptanoate, 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 peroxyneoheptanoate, di(3-methoxybutyl) peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, cumyl peroxyneodecanoate, diisobutyryl peroxide, and mixtures thereof.

[0092] The amount of initiator used may be sufficient to initiate the polymerization reaction at a desired rate. Typically, 0.01 wt % to 5 wt %, preferably 0.1 wt % to 4 wt %, based on the total weight of compounds (a), (b) and (c) in the mixture of compounds is sufficient. The amount of initiator is most preferably 0.01 to 2 wt %, based on the total weight of compounds (a), (b) and (c) in the mixture of compounds. The amount of initiator includes all values ​​and subvalues ​​therebetween, particularly including 0.01, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 4% and 4.5 wt %, based on the total weight of compounds (a), (b) and (c) in the mixture of compounds.

[0093] As is well known in the art, the above-mentioned inorganic and organic peroxy compounds may also be used alone or in combination with one or more suitable reducing agents. Examples of such reducing agents may include sulfur dioxide, alkali metal bisulfites, alkali metal sulfites and ammonium sulfites, thiosulfates, dithionites and formaldehyde sulfoxylates, as well as hydroxylamine hydrochloride, hydrazine sulfate, iron (II) sulfate, cuprous 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.

[0094] As mentioned above, the polymer latex of the present invention may be free of surfactant or contain one or more surfactants. Therefore, preferably no surfactant is added before, during or after steps (1) and (2) to obtain a polymer latex free of surfactant.

[0095] The polymer latex of the present invention may further include a protective colloid. In addition to or in place of the surfactant as described above, the protective colloid may stabilize the polymer latex. The protective colloid may be present during polymerization or added later. The protective colloid may include polyvinyl alcohol, vinyl alcohol-ethylene copolymer, silanol-modified polyvinyl alcohol, cellulose derivatives (such as methylcellulose, ethylcellulose, hydroxycellulose and carboxylcellulose), chitin, chitosan, starch, polyethylene glycol, polypropylene glycol, polyvinyl ether, gelatin, casein, cyclodextrin and combinations thereof. Based on 100 parts by weight of the polymer latex, a typical amount may be 1 to 15 parts by weight.

[0096] According to the invention, the polymerization process can be carried out in any process variant known in the art, in particular the monomers (b), (c) and (d) can be added batchwise, semi-batchwise, in a continuous feed mode, by divided feeds or by divided injections. Those skilled in the art will understand that the differences in these variants lie in how and when these specific monomers are added to the mixture of compounds during the process.

[0097] These different process variations in combination with the use of the macro RAFT agent (a) of the present invention enable the skilled person to prepare polymer latexes comprising copolymers having a predetermined monomer distribution and thus predetermined properties, depending on the intended use of the respective obtained polymer latex.

[0098] The process according to the invention may further comprise the additional step of adding further monomers after the total amount of compounds (a), (b) and (c) has been added to the reactor. Such monomers are preferably reactive at least with the functional groups present in compounds (a), (b) or (c).

[0099] It is further advantageous to carry out the emulsion polymerization in the presence of buffer substances and chelating agents. Suitable substances are, for example, alkali metal phosphates and pyrophosphates (buffer substances) and alkali metal salts of ethylenediaminetetraacetic acid (EDTA) or hydroxy-2-ethylenediaminetriacetic acid (HEEDTA) as chelating agents. The amount of buffer substances and chelating agents is generally 0.001 to 1.0% by weight, based on the total weight of compounds (a), (b), (c) and, if present, (d).

[0100] Furthermore, it may be advantageous to use chain transfer agents (regulators) in the emulsion polymerization. Typical agents are, for example, organic sulfur compounds, such as thioesters, 2-mercaptoethanol, 3-mercaptopropionic acid and C1-C12-alkyl mercaptans, preferably n-dodecyl mercaptan and tert-dodecyl mercaptan. The amount of chain transfer agent (if present) is generally 0.05 to 3.0% by weight, preferably 0.2 to 2.0% by weight, based on the total weight of the compounds (a), (b), (c) and (if present) (d) in the compound mixture.

[0101] The polymerization process according to the invention can be carried out under mechanical agitation (i.e. stirring) to achieve optimal distribution of reactants and facilitate polymerization induced self-assembly (PISA). The stirring speed can advantageously be 80 to 400 rpm, preferably 100 to 350 rpm, or as low as 50 rpm depending on the reactor design.

[0102] Furthermore, it may be beneficial to introduce partial neutralization into the polymerization process. One skilled in the art will appreciate that by appropriate selection of this parameter, the necessary control can be achieved.

[0103] Various other additives and ingredients can be added to prepare the polymer latex of the present invention. Such additives include, for example, defoamers, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, optical brighteners, crosslinking agents, promoters, antioxidants, biocides and metal chelators. Known defoamers include silicone oils and acetylene glycols. Commonly known wetting agents include alkylphenol ethoxylates, alkali metal dialkyl sulfosuccinates, acetylene glycols and alkali metal alkyl sulfates. Typical thickeners include polyacrylates (salts), polyacrylamide, xanthan gum, modified cellulose or particulate thickeners, such as silicon dioxide 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 commonly 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), and o-tolylbiguanide (OTBG).

[0104] Rubber products

[0105] Polymer latex is particularly useful for producing rubber products. Therefore, the present invention also relates to the use of polymer latex according to the present invention for producing rubber products and rubber products prepared by polymer latex according to the present invention. Such rubber products may include surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-supported gloves, household gloves, balloons, tubing, dental baffles, aprons and preformed gaskets. Such rubber products can be prepared using techniques well known in the art, including, for example, dip molding. Example:

[0106] The following examples are intended to further illustrate the present invention but are not intended to limit the scope of the present invention in any way.

[0107] Hereinafter, all parts and percentages are based on weight unless otherwise specified.

[0108] Synthesis of Macro-RAFT Polymers (Macro-RAFT) Examples

[0109] A RAFT agent, 4-((((2-carboxyethyl)thio)-thiocarbonyl)thio)-4-cyanovaleric acid (BM1433 of Boron Molecular) and an activator were added to a 250 mL or 2000 mL reactor equipped with a mechanical anchor stirrer, a nitrogen inlet and a temperature control system, wherein the molar ratio of the RAFT agent to the activator was 1:0.1, and deionized water. The mixture was stirred and bubbled under a nitrogen stream for 20 minutes. Subsequently, the temperature of the mixture was raised to 60°C, and the pre-degassed monomers were added to the reactor together with the RAFT agent having a fixed molar ratio with the monomers, and then immediately heated to 80°C. The solution quickly turned yellow and all substances dissolved. The temperature and stirring were maintained for 2 to 4 hours to obtain a macromolecular RAFT polymer with a yield of at least 95.0%. For the synthesized macromolecular RAFT polymer examples, the molar ratio of the RAFT agent to the monomers and activators used, the types of monomers and activators used, and their target molecular weights (Mw) are shown in Table 1.

[0110] Table 1 Macromolecular RAFT

[0111]

[0112] *Per 1 mol of RAFT agent

[0113] Carboxylated nitrile (XNBR) latex was synthesized using macromolecular RAFT polymer.

[0114] Example 1

[0115] 3.0 parts of Example 3 macromolecular RAFT, 33 parts of 0.5M sodium hydroxide (NaOH) aqueous solution, 0.0012 parts of sodium ethylenediaminetetraacetate (Na4EDTA) and 117.1 parts of water were added to the reactor vessel and preheated to 30°C. Subsequently, 31.0 parts of acrylonitrile (ACN) were poured into the reactor together with 0.05 parts of activator hydroperoxide cumene (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 350rpm. Finally, 0.03 parts of an aqueous solution of sodium formaldehyde sulfoxylate (SFS) were added to the reactor to start the reaction. Samples were taken during the polymerization to track the conversion. When the conversion was close to 100%, the reactor was cooled to room temperature. In order to remove residual monomers, the reactor was placed under vacuum and nitrogen flow for 1 hour.

[0116] Example 2

[0117] 2.0 parts of the macromolecular RAFT of Example 3, 22 parts of 0.5M NaOH aqueous solution, 0.0012 parts of Na4EDTA and 128.0 parts of water were added to the reactor vessel and preheated to 30°C. Subsequently, 31.3 parts of ACN were poured into the reactor together with 0.05 parts of 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 350rpm. Finally, 0.03 parts of SFS aqueous solution were added to the reactor to start the reaction. Samples were taken during the polymerization to track the conversion. When the conversion was close to 100%, the reactor was cooled to room temperature. In order to remove residual monomers, the reactor was placed under vacuum and nitrogen flow for 1 hour.

[0118] Example 3

[0119] The procedure was the same as in Example 2 except that 0.6 parts of tert-dodecyl mercaptan (tDM) and ACN were added to the reactor.

[0120] Example 4

[0121] 5.8 parts of the macromolecular RAFT of Example 5, 28.5 parts of 0.5M NaOH aqueous solution, 0.0012 parts of Na4EDTA and 121.6 parts of water were added to the reactor vessel and preheated to 30°C. Subsequently, 30.1 parts of ACN were poured into the reactor together with 0.05 parts of 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 350rpm. Finally, 0.03 parts of SFS aqueous solution were added to the reactor to start the reaction. Samples were taken during the polymerization to track the conversion. When the conversion was close to 100%, the reactor was cooled to room temperature. In order to remove residual monomers, the reactor was placed under vacuum and nitrogen flow for 1 hour.

[0122] Example 5

[0123] 3.0 parts of the macromolecular RAFT of Example 1, 36.0 parts of 0.5M sodium hydroxide aqueous solution, 0.0024 parts of Na4EDTA and 114.2 parts of water were added to the reactor vessel and preheated to 30°C. Subsequently, 31 parts of ACN were poured into the reactor together with 0.09 parts of 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 350rpm. Finally, 0.05 parts of SFS aqueous solution were added to the reactor to start the reaction. Samples were taken during the polymerization to track the conversion. When the conversion was close to 100%, the reactor was cooled to room temperature. In order to remove residual monomers, the reactor was placed under vacuum and nitrogen flow for 1 hour.

[0124] Example 6

[0125] 3.0 parts by weight of the macro-RAFT of Example 2, 0.67 parts by weight of a 5% aqueous NaOH solution (NaOH 5%) were added to the reactor vessel and preheated to 30° C. Subsequently, the monomers (31.0 parts by weight of ACN and 66.0 parts by weight of BD) were poured into the reactor along with 0.6 parts by weight of tDM, followed by 0.01 parts by weight of Na4EDTA and co-activator, 0.0262 parts by weight of SFS dissolved in 4 parts of water and 0.0474 parts by weight of activator, and CHP was added to the reactor vessel purged with nitrogen 3 times while maintaining the temperature and stirring at 30° C. and 150 rpm, respectively.

[0126] After the 6th hour, another 0.0474 parts by weight of CHP were added and after the 7th hour, 0.0262 parts by weight of SFS were added. Subsequently, the temperature was increased to 45° C. from the 8th hour and again to 60° C. from the 9th hour and maintained to a conversion of 95%, resulting in a total solids content of 40%. The polymerization was quenched by the addition of 0.0474 parts by weight of isopropylhydroxylamine IPHA.

[0127] The pH was adjusted to pH 7.0 using a 5% aqueous potassium hydroxide solution (KOH 5%), and residual monomers were removed by vacuum distillation at 60° C. for at least 8 hours. Then, 0.5 parts by weight of Wingstay L-type antioxidant (60% dispersed in water) was added to the crude latex, and the pH was adjusted to 8.0 again by adding 5% KOH. All parts added are based on the total solid content.

[0128] Example 7

[0129] 3.0 parts by weight of the macromolecular RAFT of Example 2, 0.67 parts by weight of NaOH 5% were added to the reactor vessel and preheated to 30°C while maintaining agitation 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. Then, monomers (35.0 parts by weight of ACN and 62.0 parts by weight of BD) were added together with 0.6 parts by weight of tDM over 6 hours. At the same time, a co-activator was added at a feed rate of 0.0143 parts by weight / hour of Bruggolite FF6. The temperature was maintained at 30°C until the 8th hour, then raised to 45°C and maintained to a conversion of 95%, resulting in a total solids content of 40%. The polymerization was stopped by the addition of 0.0474 parts by weight of isopropylhydroxylamine IPHA.

[0130] The pH was adjusted to pH 7.0 using 5% KOH 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 crude latex and the pH was again adjusted to 8.0 by adding 5% KOH. All parts added are based on the total solids content.

[0131] Example 8

[0132] The process was the same as in Example 7, except that the reactor temperature was increased and maintained at 45°C throughout the polymerization.

[0133] Example 9

[0134] The procedure was the same as Example 8 except that 60 parts by weight of BD was used and another 2.0 parts by weight of MAA was added over 5 minutes at the 9th hour.

[0135] Example 10

[0136] The procedure was the same as Example 8, except that 60 parts by weight of BD was used and an additional 2.0 parts by weight of MAA was added at the 5th hour within 6 hours.

[0137] Embodiment 11

[0138] 2.0 parts by weight (based on polymer solids) of seed latex (average particle size 36 nm) and 3.0 parts by weight of the macromolecular RAFT of Example 2 (based on 100 parts by weight of the monomers including the seed latex) were added to a nitrogen-purged autoclave and 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 NaPS dissolved in 2 parts by weight of water. Then, the monomers (35.0 parts by weight of ACN, 57.0 parts by weight of BD, 3.0 parts by weight of MAA) were added and added together with 0.6 parts by weight of tDM over 6 hours. Over 10 hours, 2.2 parts by weight of sodium dodecylbenzene sulfonate, 0.2 parts by weight of tetrasodium pyrophosphate and 22 parts by weight of water were added. A co-activator feed of 0.10 parts by weight of Bruggolite FF6 in 8 parts by weight of water was added over 9 hours. The polymerization temperature started at 30°C and ended at 60°C, up to 95% conversion, yielding a total solids content of 40%.

[0139] The polymerization was quenched by adding 0.08 parts by weight of IPHA solution. The pH was adjusted to pH 7.0 using 5% KOH 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 crude latex and the pH was again adjusted to 8.0 by adding 5% KOH.

[0140] Example 12

[0141] The procedure was the same as Example 11 except that 54.0 parts by weight of BD and 6.0 parts by weight of MAA were used.

[0142] Example 13

[0143] The procedure was the same as in Example 11 except that 0.88 parts by weight of sodium dodecylbenzenesulfonate was added over 5 hours.

[0144]

Claims

1. A polymer latex comprising a copolymer obtainable by free radical emulsion polymerization of a mixture of compounds comprising: (a) a macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agent obtainable by free radical polymerization of a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, ether, amine, sulfonate and / or amide function, (b) an ethylenically unsaturated monomer having a nitrile functional group; and (c) Conjugated diene monomers.

2. The polymer latex of claim 1, wherein the mixture of compounds further comprises: (d) Ethylenically unsaturated monomers 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 , wherein the RAFT agent (a1) comprises a compound having a thiocarbonyl functional group.

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

5. The polymer latex according to any one of the preceding claims, wherein the macromolecular RAFT agent (a) is capable of inducing polymerization induced self-assembly (PISA).

6. The polymer latex according to any one of the preceding claims, wherein monomer (b) comprises monomers having a total of 3 to 10 carbon atoms and combinations thereof, preferably acrylonitrile, butyronitrile and combinations thereof, more preferably acrylonitrile.

7. The polymer latex of any of the preceding claims, wherein monomer (c) comprises 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-1,3-octadiene. The invention relates to 1,6-octadiene, 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-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 and combinations thereof, preferably 1,3-butadiene, isoprene and combinations thereof, more preferably 1,3-butadiene.

8. The polymer latex according to any one of the preceding claims, wherein monomer (a2) and / or (d) comprises a monomer of the general formula R 1 C(=CH2)R 2 X monomer: R 1 is H, methyl or ethyl, R 2 is an optional linear or branched spacer group having 1 to 5 carbon atoms, and X is a carboxylic acid, ester, ether, sulfonate, hydroxyl, primary amine, secondary amine or sulfate functional group, preferably R 1 is H or methyl and X is a carboxylic acid, more preferably monomer (a2) and / or (d) comprises acrylic acid or methacrylic acid, most preferably monomer (a2) and / or (d) comprises methacrylic acid.

9. The polymer latex according to any one of the preceding claims, wherein the copolymer comprises a component having an XY structure or an XYZ structure.

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

11. The polymer latex according to any one of claims 9 or 10, wherein component X and, if present, component Z comprise monomers (a2) and / or (d), preferably wherein components X and Z do not contain monomers (b) and (c).

12. The polymer latex according to any one of the preceding claims, wherein the content of monomer (b) in the mixture of compounds is 15 to 60 parts by weight, preferably 20 to 50 parts by weight, based on the weight of the mixture of compounds.

13. The polymer latex according to any one of the preceding claims, wherein the content of monomer (c) in the mixture of compounds is 40 to 90 parts by weight, preferably 50 to 80 parts by weight, based on the weight of the mixture of compounds.

14. The polymer latex according to any one of the preceding claims, wherein the macro RAFT agent (a) is 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.

15. The polymer latex of claim 2, wherein monomer (d) is 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.

16. The polymer latex according to any one of the preceding claims, further comprising a surfactant, wherein the surfactant content in the polymer latex is 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.

17. The polymer latex according to any one of claims 1 to 15, which is a surfactant-free polymer latex.

18. A method for preparing a polymer latex comprising a copolymer, the method comprising the steps of: (1) free radically polymerizing a RAFT agent (a1) with an ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, amine and / or amide functional group to receive a macromolecular RAFT agent (a), (2) RAFT-mediated emulsion polymerization of a mixture of compounds, the mixture of compounds comprising: (a) the macromolecular RAFT agent (a) received in step (1); (b) an ethylenically unsaturated monomer having a nitrile functional group; and (c) a conjugated diene monomer, To obtain the polymer latex.

19. The method according to claim 19, wherein the method further comprises adding at least one ethylenically unsaturated monomer (a2) and / or (d) having at least one acid, hydroxyl, ester, amine and / or amide functional group to the reaction mixture during and / or after step (2), preferably wherein monomer (a2) is a monomer as defined in claim 1 and monomer (d) is a monomer as defined in claim 2, more preferably wherein monomers (a2) and (d) are monomers as defined in claim 8.

20. The process according to claim 20, wherein monomers (b), (c) and / or (d) are fed by batch, semi-batch, continuous, divided feed or divided injection.

21. The method according to any one of claims 19 to 21, wherein at least one of the following is satisfied: (i) the ethylenically unsaturated monomer (a2) having at least one acid, hydroxyl, ester, amine and / or amide function is a monomer as defined in claim 8; (ii) monomer (b) is a monomer as defined in claim 5; (iii) monomer (c) is a monomer as defined in claim 6; (iv) monomer (d) is a monomer as defined in claim 2, preferably a monomer as defined in claim 8; and / or (v) The copolymer is a copolymer as defined in any one of claims 9 to 11.

22. The method of any one of claims 19 to 22, wherein no surfactant is added before, during or after steps (1) and (2).

23. The method of any one of claims 19 to 23, wherein no inoculant is added before, during or after steps (1) and (2).

24. The method according to any one of claims 19 to 24, wherein the polymerization of step (2) is carried out at a temperature of 5°C to 95°C, preferably 30°C to 60°C.

25. Use of the polymer latex according to any one of claims 1 to 18 or the polymer latex prepared by the method according to any one of claims 19 to 25 for preparing a rubber article.

26. The use according to claim 26, wherein the rubber article comprises surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-supported gloves, household gloves, balloons, tubing, dental aprons, aprons and preformed gaskets.

27. A rubber product prepared from the polymer latex according to any one of claims 1 to 18 or from a polymer latex prepared by the method according to any one of claims 19 to 26.

28. The rubber article of claim 28, wherein the rubber article comprises surgical gloves, examination gloves, condoms, catheters, industrial gloves, fabric-backed gloves, household gloves, balloons, tubing, dental aprons, aprons, and preformed gaskets.

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