KR20000010757A - Production method of dipping-coating product - Google Patents

Abstract

PURPOSE: The dipping product having continuous polymer film formed on the surface of a dipping former by dipping the former in latex dipping composition is provided. CONSTITUTION: The heated dipping former having absorptive surface of an electrolyte is dipped in latex composition. The latex composition is stabilized by the emulsifier having anion sulfonate group. The latex has nonionic polyester group, and also has the property of heat-increase and reduction. The electrolyte absorbed on the surface of the former is Bronstead acid or salt. The free radical hydrophobic emulsion polymerization is performed under the distribution agent consisted of more than 50 wt% of soluble alkali metal salt of monosulfonic acid of C10-C20 hydrocarbon or ammonium salt.

Description

Method of Making Dipping-Coated Products

The present invention relates to a process for producing an immersion product in which the immersion type is immersed into an aqueous latex immersion composition such that a continuous polymer film is formed on the surface of the molded immersion form.

Aqueous emulsions (polymer aqueous dispersions) are widely known. These are fluid systems in which the dispersed phase in the aqueous dispersion comprises a polymer coil (referred to as polymer particles) consisting of a plurality of intertwined polymer chains and is dispersed and distributed.

Unlike the polymer solution, the emulsion does not form a thermodynamically stable system. Instead, this system tends to reduce the interface of the polymer / dispersion medium by joining the primary small particles to form larger secondary particles, and the bonding process is capable of stabilizing the interface of the dispersant (dispersed polymer / water dispersion medium). Material) can be prevented for a relatively long time in a dispersed distribution in an aqueous medium.

This means that the polymer aqueous dispersion has the potential to form a coherent polymer matrix when the dispersant loses activity by partial or complete melt of dispersed polymer particles.

Chemical bonding of the different polymer chains in the polymer particles generally tends to be disadvantageous in terms of the formation of the polymer matrix described above, but the chemical bonding (crosslinking) of the polymer chains that make up the matrix, often occurring after the polymer matrix is formed, is often It is desirable to achieve mechanical properties (eg elasticity).

This situation setting is known and free radical aqueous emulsion polymerization of a mixture of monomers containing at least one ethylenically unsaturated group, wherein at least 30% by weight consists of monomers having two conjugated double bonds which are ethylenically unsaturated. It is used to prepare the immersion product from the polymer aqueous dispersion which can be obtained by.

At a temperature where this type of free radical aqueous emulsion polymerization is not too high, it is possibly carried out using conventional molecular weight modifiers such as mercaptans (eg tert-dodecyl mercaptan or n-dodecyl mercaptan) In this case, it is common for virtually only one of the two ethylenically unsaturated conjugated double bonds to participate in the polymerization reaction.

As a result, the dispersed polymer coil has a polymer dispersion composed of polymer chains on one side that are virtually not crosslinked (ie, not chemically bonded to one another) but on the other side still have ethylenically unsaturated double bonds. The desired polymer matrix is formed by a known sulfur-based vulcanizing system which is obtained, which is usually incorporated into the polymer aqueous dispersion with or without additional adjuvant before the polymer matrix is formed, thereby forming an aqueous emulsion composition (hereinafter And an aqueous emulsion dipping composition), which can be activated at elevated temperature and allow the desired reaction to occur while forming intramolecular crosslinking, thereby obtaining a degree of crosslinking that matches the desired performance characteristics. .

Typical aqueous emulsion dipping compositions include the components of Table 1 below (see, eg, Kautschuk-Handbuch [Rubber handbook], Volume 4, Berliner Union Verlag, Stuttgart, 1961, p. 247).

ingredient Parts by weight Dispersion-dispersed polymer 100 sulfur 0.25 to 2.5 Zinc Oxide as a Vulcanization Activator 0.25 to 10 Vulcanization Accelerator 0.5 to 1.5 Anti aging agents 0.5 to 1.0 Insoluble Inorganic Filler 0 to 10 coloring agent 0 to 1.5 Plasticizer 0 to 10

The use of vulcanization accelerators is required due to the slow reactivity of sulfur and the olefinically unsaturated second groups of copolymerized conjugated dienes. The most important promoters are thiazole (also referred to as mercapto promoter), 2-mercaptobenzothiazole, zinc salts thereof and dibenzothiazyl disulfide, benzothiazyl-2-cyclohexylsulfenamide, benzothia Sulfenamides such as vagin-2-tert-butylsulfenamide, benzothiazyl-2-sulfenmorpholide, and benzothiazyl-dicyclo-hexylsulfenamide, diphenylguanidine, di- ortho-tolylguanidine and ortho-tol Guanidines such as rilgivianidine, thiurams such as tetramethylthiuram disulfide and tetraethylthiuram disulfide, zinc N-dimethyldithiocarbamate, zinc N-diethyldithiocarbamate, zinc N-dibutyl Dithiocarbamate, such as dithiocarbamate, zinc N-ethylphenyldithiocarbamate and zinc N-pentamethylenedithiocarbamate, such as ethylenethiourea, diethylenethiourea and diphenylthiourea Thiylene water , And also aldehyde-amine condensation product, for example the condensation product of formaldehyde and aniline butyral. In many cases, mixtures of vulcanization accelerators are also used.

In order to obtain their optimum activity, the vulcanization accelerator usually requires the addition of zinc oxide as an activator.

The responsiveness to the sulfur of the unsaturated groups still present in the emulsion dipping composition allows on the one hand vulcanization and on the other hand has the effect of inducing sensitivity to reactive influencers such as O ₂ and UV rays. As a result of this interaction, the latex can become hard and brittle (aging). Bacterial attack on organic polymers is another cause of aging. Therefore, in order to counteract these effects, it is common to add anti-aging agents such as Wingstay® L to the milk immersion composition. By adding fillers and / or plasticizers it is possible to influence the properties of the immersed product.

In the dipping process, the molding dip is then immersed in the aqueous latex dipping composition, and the cohesive polymer film is deposited as a polymer matrix on the surface of the molding dipping through controlled coagulation. The molding dip is then removed from the aqueous latex dip composition and dried, and the polymer film surrounding the molding dip is vulcanized by thermal action, followed by vulcanized dip products (e.g., nipples, condoms, medical gloves, surgical gloves, Industrial gloves, household gloves, finger wraps, balloons or medical specialty products) are removed from the immersion type, washed and dried as necessary, possibly powdered or chlorinated.

For controlled coagulation on solid surfaces, two different principles have been realized in the prior art: a) electrolyte coagulation and b) thermal coagulation.

For electrolyte coagulation, aqueous emulsion immersion compositions are used in which the aqueous emulsion predominantly stabilizes in its dispersed distribution with a suitable anionic emulsifier.

The term emulsifier in the prior art has a relative molecular weight of ≤ 1000 and the surface tension (σ) of water is 25% or more (pure surface tension) until a critical micelle concentration is obtained when dissolved in water (25 ° C. and 1 atm). Refers to a surfactant that can be reduced). In contrast, the term surfactant, as used herein, refers only to amphipathic materials that can reduce the surface tension of pure water when dissolved in water (25 ° C. and 1 atmosphere). The term definite adjective amphipathic refers to a surfactant having both hydrophilic and hydrophobic groups. Anionic emulsifiers are those in which hydrophilic groups in an aqueous medium have negative charges, as opposed to small monovalent cations such as alkali metal ions or ammonium ions which have little effect on their surface-utilization properties.

The dispersed polymer particles acquire surface negative charges by orientationally adsorbing anionic emulsifiers on their substantially nonpolar surfaces, thereby stabilizing their dispersion distribution state through mutual repulsion of the same charges.

Nonionic emulsifiers, on the other hand, have no ionic charge in the aqueous medium. The hydrophilicity of their hydrophilic groups is instead caused by the polarity of generally increased numbers of covalently bonded oxygen.

Thus, the principle of electrolytic coagulation is that electrolytes in which their cations interact with anionic emulsifier groups (materials that dissociate into anions and cations in the presence of water) in a manner that results in a controlled decrease in the stabilizing effect of the anionic emulsifier groups to initiate the desired coagulation. ) Is dipped into an immersed aqueous emulsion dipping composition which is adsorbed onto the surface as a coagulant.

Accordingly, an electrolyte coagulation requires an aqueous emulsion dipping composition that reacts sensitively to the addition of an electrolyte, while thermal coagulation requires an aqueous emulsion dipping composition that reacts sensitively to an increase in temperature. To achieve this, a coagulant is added which becomes active at a temperature just above the freezing point, which is a certain temperature. When the immersion type is immersed in an aqueous latex immersion composition thermally sensitized in this manner at elevated temperature, solidification occurs on the surface of the immersion type and until the surface temperature of the immersion type remains permanently below the preset freezing point of the aqueous emulsion immersion composition. Solidification persists.

The preparation of immersion products based on pure thermal coagulation is described in the prior art (Kautschuk-Handbuch [Rubber Handbook], Volume 4, Berliner Union Verlag, Stuttgart, 1961, pp. 252-256; High Polymer Latices, DC Blackley, Vol. .2, Maclaren & Sons Ltd., London, 1966, p. 532; DE-AS 12 43 394; DE-A 14 94 037; Ullmanns Encyclopaedie der technischen Chemie [Ullmann's Encyclopedia of Industrial Chemistry], Verlag Chemie , Weinheim, Vol. 13 (Hormone-Keramik), 1977, p. 676; Bayer-Mitteilungen fuer die Gummi-Industrie, Vol. 32, Annual series 63, pp. 56-69).

During immersion, it is advantageous as long as the thickness of the deposited polymer matrix can be obtained thick in a relatively short time.

Disadvantages of the above-described techniques include the need for a uniform immersion type within a very narrow range of temperature and heat capacity for uniform thickness of the immersion product. Moreover, particularly high removal rates are required to obtain a uniform film thickness along the length of the immersion type. In addition, the mechanical properties of the resulting immersed product are in many cases not entirely satisfactory.

The preparation of immersion products based on pure electrolyte coagulation is likewise described in the prior art (e.g. US-A 2 880 189; EP-A 378 380; 456 333; Kautschuk-Handbuch (Rubber Handbook), Volume 4, Berliner Union Verlag, Stuttgart, 1961, pp. 246-252; High Polymer Latices, DC Blackley, Vol. 2, Maclaren & Sons Ltd., London, 1966, pp. 530-532; Ullmanns Encyclopaedie der technischen Chemie [Ullmann's Encyclopedia of Industrial Chemistry], Verlag Chemie, Weinheim, Vol. 13 (Hormone-Keramik), 1977, p. 676; Bayer-Mitteilungen fuer die Gummi-Industrie, Vol. 32, Annual series 63, pp. 56 -69).

Advantages of immersion product manufacture by electrolytic coagulation include increased reproducibility in immersion product thickness and desirable mechanical properties of the resulting product. The disadvantage is that the immersion time required for a given film thickness is increased, due to the specific time it takes for the coagulation electrolyte to diffuse through the thickening film and to solidify another portion of the aqueous emulsion immersion composition.

It is an object of the present invention to provide a method for producing an immersion product which combines the advantages of electrolyte coagulation with the benefits of thermal coagulation, in which the immersion type is immersed into an aqueous latex immersion composition.

The inventors have found that this object is at a temperature T at which the electrolyte is adsorbed on the surface as a coagulant and usually at 1 atmosphere, containing at least one ethylenically unsaturated group and at least 30% by weight of two ethylenically unsaturated conjugated doubles. The immersion type is immersed into the aqueous emulsion immersion composition to which the components of Table 2 are added based on the weight of the dispersed polymer, including the polymer aqueous dispersion obtained by the free radical aqueous emulsion polymerization method of the monomer having the bond,

Provided that the electrolyte adsorbed on the immersed surface is Bronsted acid and / or salt,

Free radical aqueous emulsion polymerization takes place in the presence of a dispersant of at least 50% by weight consisting of a water-soluble alkali metal salt and / or ammonium salt of monosulfonic acid of C ₁₀ -C ₂₀ hydrocarbons,

The aqueous latex immersion composition is a thermal coagulant added, comprising a nonionic organosilicon surfactant containing a polyether group and having a cloud point of 20 to 60 ° C., preferably 30 to 40 ° C.,

The temperature T is higher than the cloud point of the organosilicon surfactant, conveniently 40 to 150 ° C., advantageously 60 to 90 ° C.

It was finally discovered that this is achieved by the method of making the immersion product.

weight% ingredient 0.25 to 2.5 sulfur 0.25 to 10, preferably 0.5 to 5.0 Zinc oxide 0.5 to 1.5 Vulcanization Accelerator 0.5 to 1.0 Anti aging agents 0 to 10 Insoluble Inorganic Filler 0 to 1.5 coloring agent 0 to 10 Plasticizer

The cloud point is the temperature at 25 ° C. when an aqueous solution of a transparent polyether-modified organosilicon compound separates into two phases while the temperature is increased (the cloud point is generally based on a 4% by weight aqueous solution of surfactant). The novel action of the organosilicon surfactants described above is believed to be based on their ability to hydrate and dissolve in low temperature aqueous media. When the temperature is elevated, spontaneous dehydration is evident with phase separation resulting from the bonding between the adducts and the adduct with the sulfonate used as emulsifier when reaching cloud point, which causes sudden latex coagulation.

The simplest polyether-modified nonionic organosilicone surfactants used (known and commercially available) according to the invention are described, for example, in DE-B 12 43 394, 17 94 418 and DE-A. There is a polyether-modified siloxane containing a hydrophobic group as described in heading 14 94 037. However, these also include polyether-modified nonionic organosilicone surfactants in which the polyether-modified organosilicon compound is grafted as a hydrophilic moiety on a polymer of conjugated diene as a hydrophobic moiety, preferably poly-1,2-butadiene. Which is disclosed, for example, in DE-A 32 18 676, US 23 21 557 and DE-C1 37 18 588. Suitable modified polyether groups are homo- and copolymers of alkylene oxides, for example ethylene oxide, propylene oxide or isobutylene oxide. Preference is given to homopolymers of ethylene oxide. In general, the number average relative molecular weight of the nonionic polyether-modified organosilicon surfactants used according to the invention is greater than 1000 and less than 50,000. Preferred such surfactants are the commercially available products from BASF AG, Basensol® HA 5 (cloud point: 38 ° C.) and Coagulant WS from Bayer AG. : 32 ° C.).

Based on the amount of dispersed polymer present in the aqueous emulsion immersion composition used according to the invention, the amount of polyether-modified organosilicon compound required according to the invention is generally 0.1 to 5% by weight.

Among the alkali metal salts and / or ammonium salts of C ₁₀ -C ₂₀ hydrocarbon sulfonates used according to the invention for free radical aqueous emulsion polymerization, sodium salts are preferred.

Specific examples that may be mentioned include sodium dodecylsulfonate, sodium myristylsulfonate and sodium stearylsulfonate as sulfonates of aliphatic C ₁₀ -C ₂₀ hydrocarbons, and sodium dodecylbenzenesulfonate as alkylarylsulfonates. . Mixtures of such C ₁₀ -C ₂₀ hydrocarbon sulfonates which are widely available commercially (eg C _10- , C ₁₂ -and C ₁₃ -alkylbenzenesulfonate mixtures, or C _14- , C _15- , C ₁₆ -And C ₁₇ -alkanesulfonate mixtures).

For free radical aqueous emulsion polymerization according to the invention, 0.1 to 5% by weight, mostly of water-soluble alkali metal salts and / or ammonium salts of monosulfonic acids of C ₁₀ -C ₂₀ hydrocarbons, based on the amount of dispersed emulsion polymer produced In the case of 0.5 to 2% by weight is generally used.

In addition to alkali metal salts and / or ammonium salts of monosulfonic acids of the C ₁₀ -C ₂₀ hydrocarbons required according to the invention, other dispersants of up to 50% of the total amount of dispersant used in the free radical aqueous emulsion polymerization can be considered. .

Examples thereof include other anionic and / or nonionic emulsifiers and / or surfactants such as ethoxylated mono-, di- and trialkylphenols (EO degrees: 3 to 100, alkyl: C ₄ -C _12). ), Sulfuric acid half-ester of ethoxylated alkanol of ethoxylated fatty alcohol (EO degree: 3 to 100, alkyl: C ₈ -C ₁₈ ), alkyl sulfate (alkyl: C ₈ -C ₁₆ ) To 70, alkyl: C ₁₂ -C ₁₈ ), aryl sulfates and alkylaryl sulfates (alkyl: C ₉ to C ₁₈ ), and alkalis of C ₈ -C ₁₈ fatty acids and disproportionate resin acids obtained from rosin Metal salts and ammonium salts. Of course, other suitable such dispersants include protective colloids such as polyvinyl alcohol, cellulose derivatives, copolymers containing vinylpyrrolidone, or polycondensates of naphthalenesulfonic acid with formaldehyde. Unlike emulsifiers and surfactants, they cannot form micelles in aqueous polymerization media and generally have a relative molecular weight> 1000. Moreover, they have little effect on the surface tension of water. The relative molecular weights of the suitable polycondensates of naphthalenesulfonic acid with formaldehyde (or their water soluble salts) are for example 4000 to 8000. Combinations of emulsifiers and protective colloids will often be used with polymerized monomers with markedly different water solubility, if desired, in the case of polymer dispersions where the dispersed polymer particles are maximally uniform from a chemical point of view. The diameter of the resulting emulsion polymer particles is generally determined by the absolute amount of emulsifier used. The weight average diameter is preferably 80 to 300 nm, particularly preferably 100 to 250 nm, very particularly preferably 100 to 200 nm.

The amount of other dispersants used (in addition to the sulfonates required according to the invention) is advantageously 25% or less, or 10% or less of their total amount. A preferred embodiment of the invention is when no further dispersant is used.

In order to prepare a polymer aqueous dispersion which forms the main component of the aqueous emulsion immersion composition used according to the invention, the monomer mixture polymerized by the free radical aqueous emulsion polymerization method is a monomer containing only two ethylenically unsaturated conjugated groups. It may further comprise a comonomer comprising (monomer A) or different from monomer A and containing at least one ethylenically unsaturated group. The proportion of monomer A in the monomer mixture polymerized according to the invention is frequently from 30 to 90% by weight, often from 40 to 70% by weight and in many cases from 50 to 70% by weight. Examples of possible monomers A are butadiene, 2-methylbutadiene, 2,3-dimethylbutadiene, 1,3-pentadiene or 2,4-pentadiene, or mixtures thereof. Monoethylenically unsaturated comonomers (monomer B) having an atmospheric pressure (1 atm) and an increased molar water solubility (greater than the water solubility of acrylonitrile) at 25 ° C. are generally at most 10% by weight, often from 3 to Included in the mixture of monomers polymerized in an amount of 8% by weight. Examples of typical monomers B include α, β-monoethylenically unsaturated C ₃ -C ₆ mono- and dicarboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, especially salts thereof Alkali metal salts and ammonium salts), amides thereof such as acrylamide and methacrylamide, and also vinylsulfonic acid and its water-soluble salts (particularly alkali metal salts and ammonium salts), and N-vinylpyrrolidone . It is of course also possible to use monomers B as mixtures. Butadiene is the preferred monomer A, while methacrylic acid is preferred as the monomer B.

The proportion of other copolymerizable monomers (monomer C) containing ethylenically unsaturated groups can be up to 70% by weight. The proportion of monomer C is frequently from 10 to 70% by weight, often from 30 to 60% by weight, in many cases from 30 to 50% by weight. Examples of suitable monomers C include vinyl-aromatic monomers such as styrene, vinyltoluene or o-chlorostyrene, acrylonitrile, methacrylonitrile, and esters of acrylic acid or methacrylic acid with C ₁ -C ₈ alkanols and their There are mixtures, of which styrene, acrylonitrile and methyl methacrylate, and mixtures thereof, are particularly suitable as monomers C.

As a result, suitable aqueous dispersions of free radical aqueous emulsion polymers are those obtained from monomer mixtures consisting of 30 to 100% by weight of monomer A, 0 to 10% by weight of monomer B and 0 to 70% by weight of monomer C.

These are

30 to 100% by weight of one or more monomers from the group consisting of butadiene, 2-methylbutadiene and 2,3-dimethylbutadiene,

0-10% by weight of one or more monomers from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, and acrylamide and methacrylicamide, and

0 to 70% by weight of one or more monomers from the group consisting of styrene, acrylonitrile and methyl methacrylate

Free radical aqueous emulsion polymers of monomer mixtures.

In particular, they comprise free radical aqueous emulsion polymers of monomer mixtures consisting of 30 to 100% by weight butadiene, 0 to 10% by weight methacrylic acid and 0 to 70% by weight acrylonitrile.

When the weight percentage ratios of the aforementioned combinations of monomers A, B and C are as follows, a suitable free radical aqueous emulsion polymer is likewise produced using the monomer mixtures described above:

30 to 90 weight percent of monomer A, 1 to 10 weight percent of monomer B and 9 to 60 weight percent of monomer C, or

40 to 80 weight percent of monomer A, 1 to 10 weight percent of monomer B and 19 to 50 weight percent of monomer C, or

45 to 70 weight percent of monomer A, 3 to 10 weight percent of monomer B and 27 to 45 weight percent of monomer C.

This is especially the case when monomer A is only butadiene, monomer B is only methacrylic acid and monomer C is only acrylonitrile.

As already mentioned, in order to limit the degree of crosslinking, free radical aqueous emulsion polymerization is generally a molecular weight modifier such as, for example, mercaptan (alkanthiol) advantageously mercaptan (alkanthiol) having 3 to 15 carbon atoms. Occurs in the presence of a (chain transfer agent). In general, tert-dodecyl mercaptan and / or n-dodecyl mercaptan are used as such modulators. Free radical aqueous emulsion polymerization typically takes place in the presence of 0.1 to 3%, often 0.5 to 1.5%, by weight of such modifiers, based on the monomers being polymerized.

Suitable free radical polymerization initiators for carrying out the aqueous emulsion polymerization are in principle all those capable of initiating such polymerization. These include both peroxides and azo compounds. In order to limit the degree of crosslinking of the resulting emulsion polymer, an initiator system that decomposes at < As a result, preference is given to using a combined system of at least one reducing agent and at least one peroxide and / or hydroperoxide, in which the reducing agent activates the formation of free radicals so that the new free radical aqueous emulsion polymerization is low temperature. This is because it can be started from.

Examples of suitable reducing agents are ascorbic acid, acetone bisulfite, sodium hydroxymethanesulfinate, sodium sulfite, sodium bisulfite or sodium dithionite. Particularly preferred above-mentioned binding (redox initiator) systems also include small amounts of metal compounds which are soluble in the polymerization medium and whose metallic components may be present in two or more valence states.

Examples of such metal compounds are iron (II) salts such as iron (II) sulfate. Instead of water-soluble iron (II) salts, combinations of water-soluble Fe / V salts are often used. Redox initiator systems of this type containing such metal compounds are advantageous as long as the new free radical aqueous emulsion polymerization can be started even at lower temperatures. Examples of such redox initiator systems include ascorbic acid / iron sulfate (II) / hydrogen peroxide or sodium dithionite and / or sodium formaldehyde sulfoxylate / iron sulfate (II) / paramentane hydroxide peroxide or diisopropyl Benzene hydroperoxide or cumene hydroperoxide. In many cases, redox initiator systems of this type containing metal compounds are also added with small amounts of chelating agents to ensure that metallic components are present in solution and not removed from the reaction system, for example as a result of the precipitation reaction. Examples of such chelating agents are the sodium salts of ethylenediaminetetraacetic acid. Metallic components are often added directly in the form of chelate complexes in practice.

The amount of initiator used is generally from 0.01 to 5% by weight, in most cases from 0.01 to 1% by weight, based on the monomers to be polymerized. According to the invention, the polymerization is usually carried out in an inert gas atmosphere. Sodium dithionite is likewise suitable as a trapping agent for residual oxygen. Moreover, it is also possible to add pH buffers, such as alkali metal phosphates, to stabilize the pH of the aqueous dispersion during emulsion polymerization. The addition of small amounts of strong electrolytes such as potassium sulfate, potassium chloride and / or sodium sulfate is known to facilitate achieving the desired polymer particle diameter by controlling the influence of the polymer particle diameter on particle formation.

Very generally, the temperature, the nature and amount of the molecular weight modifier, and the polymerization conversion rate advantageously favor the transversal nuclear-magnetic relaxation time ( ^1H T of the protons with the crosslink density chemically bound to the polymer). ₂ ) is coordinated with each other to give a polymer aqueous dispersion of 2.5 to 4.5 ms. These values relate to the respective polymer aqueous dispersion specimens formed at 25 ° C. and then dried at 80 ° C. for 2 hours, measured at 140 ° C. and ¹ H resonance frequency 20 MHz. The relationship between ^1H T ₂ and crosslink density is taught, for example, in Macromolecules 27 (1994) 2111-2119. This relationship ultimately states that, on the one hand, the transversal nucleus-magnetic relaxation time of an atomic nucleus with magnetic moments is a measure of its motility in the external magnetic field, and on the other hand, crosslinking of different polymer chains with each other limits their motility. Depends on the facts Thus, the lower the motility of the polymer chain, the greater the crosslink density, and the shorter the transverse nuclei-magnetic relaxation time of the atomic nucleus chemically bonded to this polymer chain and having a magnetic moment.

The conversion of the free radical aqueous emulsion polymerization is stopped if necessary, usually by the addition of a polymerization inhibitor such as dimethylhydroxylamine, and then the monomers which are still unreacted are then subjected to deodorization (preferably stripping and / or steam distillation). By itself in a manner known per se.

The realization of free radical aqueous emulsion polymerization as described above is disclosed, for example, in DE-A 195 45 096.

The simplest embodiment of free radical aqueous emulsion polymerization introduces the entire polymerization batch except the polymerization initiator moiety into the polymerization vessel as an initial formulation and starts the polymerization by heating the formulation to the polymerization temperature, until the desired conversion is achieved. Continuing the free radical aqueous emulsion polymerization by continuing to add the remaining free radical initiator and maintaining the polymerization temperature. If monomers are used that are difficult to remove as residues from the product mixture (eg acrylonitrile) at the end of the polymerization, monomers of the type that are more easily removable by adding them separately at the end of the polymerization (eg , Butadiene) may be convenient.

Another embodiment of the free radical aqueous emulsion polymerization is provided by a continuous feed method of monomers. In this case, only a small amount of the monomer to be polymerized is initially blended into the polymerization vessel, and is conveniently subjected to initial polymerization in the presence of the added seed emulsion, and then the remaining amount of monomer to be polymerized is transferred to the polymerization vessel according to the rate at which they are consumed. The polymerization is maintained while feeding continuously.

In general, the polymer aqueous dispersions used according to the invention are prepared from 30 to 70% by volume solids, generally from 40 to 50% by volume.

In order to prepare aqueous emulsion immersion compositions for use in the novel process, the vulcanized and nonionic polyether-modified organosilicone surfactants, which are required with or without additional auxiliaries, are typically used in free radical aqueous emulsion polymerization processes. It is incorporated in the polymer aqueous dispersion obtained.

Thermal sensitizers are advantageously incorporated at the end. Residual materials to be incorporated essentially comprise solids which need to be incorporated in as finely a form as possible to maximize their action. Powders generally have a high water absorption ability and are therefore difficult to incorporate into the polymer aqueous dispersion in a dry state, since the powder removes the serum from the emulsion and in some cases causes coagulation. Other finely divided solids have a coagulation effect as a result of the fact that they have a high surface positive charge, not particularly due to high absorption. As a result, powdered solids need to be prepared before they are incorporated into the emulsion such that they cannot cause coagulation for these reasons. Thus, they are conveniently prepared into pastes using water, usually to which protective colloids are added (generally by treatment in a ball mill for at least 24 hours). These colloids also prevent subsequent agglomeration of the powder particles and have a high affinity for them. Suitable protective colloids in this respect include, for example, the water-soluble alkali metal salts of naphthalenesulfonic acid-formaldehyde condensates (e.g., Tamol® NN 4501 from BASF AG; 45% aqueous solution of sodium salt of naphthalenesulfonic acid-formaldehyde condensate which is 6500 or a partially soluble ester of styrene-maleic anhydride copolymer (C ₁ -C ₆ alkanol) (e.g. 625 g of water) , 250 g of a 10% aqueous potassium hydroxide solution and a methyl / isobutyl portion of Scrripset 540 (styrene-maleic anhydride (1: <1 mole) copolymer having a weight average relative molecular weight of 180,000) Ester) 540) prepared by mixing 125 g). In many cases, the thickener may also be used as an aqueous paste (e.g., Collate® AS / RK, Collate A / RN or Cola from Kelco to achieve consistency similar to paste). Tex A / RE; these compounds are preferably added to 350-650 mPa · s (ammonium alginate having a viscosity of 20 ° C., Brookfield viscometer, model LV, 60 rpm, spindle 3) in its 1% aqueous solution. Vulcanization accelerators that may be used include both water soluble and water insoluble compounds. Water insoluble promoters are preferred because they are not absorbed by the porous submerged type. Among these, those which are actually important include, in particular, ultra- accelerators of dithiocarbamates (eg, zinc N-diethyldithiocarbamate, zinc N-dimethyldithiocarbamate, zinc N- Dibutyldithiocarbamate or zinc N-phenylethyldithiocarbamate) and the less potent promoting compounds of the mercaptobenzothiazole class (eg, zinc mercaptobenzothiazole). These solid vulcanization accelerators are likewise conveniently incorporated in the form of an aqueous paste.

Another portion of the adjuvant incorporated includes a viscous liquid (eg wingstay S = antioxidant (antioxidant)), which is generally incorporated in the form of an aqueous emulsion. In this case, the emulsifiers and / or surfactants used are preferably also suitable for carrying out free radical aqueous emulsion polymerization, in particular those having a high affinity for the liquid to be emulsified. Anti-aging agents also include Naugawhite® and Proxel® XL2 (Fungicides).

Examples of possible inorganic fillers which are insoluble in the aqueous medium are quartz powder and also calcium silicate or aluminum silicate. Particularly suitable colorants are the Vulkanosol dyes and the Halizarin® pigments from BASF AG. Possible plasticizers include oils such as mineral oil, paraffin oil or dibenzyl ether, which are likewise incorporated in the form of an aqueous emulsion.

Suitable electrolytes present in adsorbed form on the immersed surface include salts of monovalent or polyvalent cations such as calcium nitrate, calcium chloride, aluminum sulfate, magnesium nitrate or zinc nitrate, depending on the invention and the characteristics of the anionic sulfonate group. They preferably have good solubility in water and also in acids such as Bronsted acid, in particular formic acid, acetic acid or lactic acid. Mixtures of such electrolytes are of course also suitable. Application of the electrolyte to the surface of the immersion type is preferably carried out by first immersing the immersion type into the electrolyte and then drying it. Suitable solvents include lower alcohols such as methyl and ethyl alcohol, water and / or mixtures thereof. In order to prevent the coagulant solution from coalescing and evenly wetting as it flows out of the immersion type, the initial immersion solution is usually and usually a wetting agent (e.g. Lutensol® AP 10 Such as ethoxylated alkylphenols). Substances proven to be suitable for immersion include glass, porcelain, ceramics, or light metals that do not contain Cu and Mn. In many cases these materials are also surrounded by fabric tissue which serves as a substrate for the resulting immersion product. Of course, heated immersion types are also suitable. The temperature of the aqueous emulsion immersion composition in which the immersion type is immersed in the course of the new process is generally 10 to 40 ° C., usually 10 to 30 ° C., and is usually lower than the cloud point of the nonionic organosilicon surfactant. After the immersion type is freshly immersed into the aqueous latex immersion composition, the polymer film deposited on the surface of the immersion type is generally washed, dried, hot air vulcanized and finally peeled off, washed again as needed, and powdered as necessary. Or chlorinated. It is of course also possible to carry out a plurality of sequential immersion operations in order to obtain particularly thick film thicknesses.

The novel process ensures films of quality corresponding to the increased thickness, improved reproducibility and quality obtained upon electrolyte immersion alone with short immersion times. Moreover, the resulting film has particularly improved handleability required for the manufacture of medical gloves. The dipping time required for a particular film thickness can also be influenced by varying the polymer content of the aqueous latex dipping composition. Higher polymer contents generally require shorter dipping times. In many cases, the aqueous latex immersion composition is made alkaline with NH ₃ and left for an extended period of time before immersion (aging). During this period, some of the ZnO dissolves, which proves often advantageous in the case of carboxylated polymers. In some cases, alkali metal hydroxides such as NaOH are used instead of NH ₃ . The novel method is suitable for producing immersion products, for example with a film thickness of 0.04 mm to 2 mm. Related immersion products include those known per se, such as gloves, condoms, nipples, inflatable balloons, finger wraps and the like.

A) Preparation of Latex L I and L II Suitable for Dipping Products

LI: The polymerization was carried out by adding Na dithionite under N ₂ atmosphere, which in this case acted as an oxygen trapping agent.

The polymerization vessel (agitated pressurized reactor made of V2A stainless steel) was charged with 52 kg of water, 23.52 kg of butadiene (47.3 wt%), 20.82 kg of acrylonitrile (41.9 wt%), 2.90 kg of methacrylic acid (5.8 wt%), 3.47 kg of 40 wt% aqueous solution of Na salt of secondary alkanesulfonic acid (C ₁₃ / C ₁₇ mixture), 1.03 kg of 45 wt% aqueous solution of naphthalenesulfonic acid-formaldehyde condensate, corresponding to tamol NN 4501 (number average relative molecular weight: 6500), Charged with a mixture of 86 g of sodium sulfate and 40 g of a 40% by weight aqueous solution of the disodium salt of ethylenediamine tetraacetic acid and cooled to 8 ° C.

Still at this temperature, after adding 1.5 g of sodium dithionite, 4 g of sodium formaldehyde-sulfoxylate, 609 g of tert-dodecyl mercaptan and Sequestrene® Na-Fe (ethylene 1.5 g of mixed Na—Fe salts of diaminetetraacetic acid) were all added in one portion. Subsequently, 9.0 g of a 90.5% aqueous solution of cumene hydroxide peroxide were added all at once, and the polymerization was still carried out at 8 ° C. until a conversion of 40 mol% was obtained. The polymerization was then added all at once by adding a mixture of 0.45 g of cequestrene Na-Fe, 4 g of sodium formaldehyde-sulfoxylate and 400 g of water, and 11 g of 90.5 wt% aqueous solution of cumene hydroxide peroxide all at once. The polymerization was still continued at 8 ° C. until a conversion of 60 mol% was obtained. Subsequently, the polymerization temperature was raised to 10 ° C, and polymerization was continued until the polymerization conversion rate reached 75 mol% at this temperature.

In a single addition, 2.51 kg of butadiene (5% by weight), and a mixture of 0.45 g of cequestrene Na-Fe, 4 g of sodium formaldehyde-sulfoxylate and 3.7 kg of water, and a 90.5% by weight aqueous solution of cumene hydroxide peroxide The polymerization was continued at 15 ° C. until 11 g was added all at once and the polymerization conversion reached 98 mol%.

The polymerization was stopped at the above-mentioned conversions by adding a mixture of 590 g of 25% by weight aqueous ammonia, 30 g of diethylhydroxylamine and 500 g of water. Solids of the resulting polymer aqueous dispersion were 45.5 wt%.

After addition of 500 g of 50 wt% aqueous solution of naugawhite and 100 g of water, most of the remaining monomers were removed by steam stripping. Solids of the final polymer aqueous dispersion were 44.7 wt%. The weight average polymer particle diameter (d _w ) was 110 nm and the ^1H T ₂ value of the film was 4.1 ms.

L II: The polymerization was carried out under N ₂ atmosphere.

Raw material feed vessel I was fed with raw material stream I consisting of 11.1 kg of acrylonitrile (24% by weight), 22.7 kg of butadiene (49.1% by weight), 1.38 kg of methacrylic acid (2.9% by weight) and 305 g of tert-dodecyl mercaptan. Filled.

Raw material feed vessel II was charged with raw material stream II consisting of 5 kg of water and 2.4 kg of a 40 wt% aqueous solution of Na salt of secondary alkanesulfonic acid (C _13- / C ₁₇ mixture).

The polymerization vessel (a stirred pressurized reactor made of V2A stainless steel) was subjected to 12.9 g of disodium salt of ethylenediaminetetraacetic acid, 5.53 kg of butadiene (12% by weight), 5.54 kg of acrylonitrile (12% by weight), 33.5 as seed emulsion It was filled with a mixture of 760 g of wt% polystyrene aqueous dispersion (d _w = 30 nm, containing 20 wt% Na dodecylbenzenesulfonate based on the mass of polystyrene as dispersant) and 37.6 kg of water and conditioned at 53 ° C. Then 930 g of ammonium peroxodisulfate was added to the polymerization vessel and the resulting mixture was polymerized at 53 ° C. for 0.5 h. Subsequently, feed stream I (over 7 hours) and feed stream II (over 9 hours) were fed into the polymerization vessel, starting at the same time at 53 ° C. After addition of both feed streams II, the polymerization mixture was further stirred at 53 ° C for 8 hours. The polymerization was then stopped by adding a mixture of 180 g of 25% by weight aqueous ammonia, 1600 g of water, 46 g of hydroxylamine sulfate and 4.5 g of Na dodecylbenzenesulfonate. Solids of the resulting polymer aqueous dispersion were 49.8% by weight.

After addition of a mixture of 500 g of water and 2.4 kg of a 40 wt% aqueous solution of Na salt of secondary alkanesulfonic acid (C _13- / C ₁₇ mixture), the remaining monomers were mostly removed by steam stripping.

Solid content of the final polymer aqueous dispersion was 48.6% by weight. The weight average polymer particle diameter (d _w ) was 180 nm and the ^1H T ₂ value of the film was 2.6 ms.

B) Preparation of Latex Dipping Compositions LT I to LT III and Control Latex Dipping Compositions VLT I to VLT III

LT I: mixture of 953 g of Wingstay-S, 8.5 g of Na dodecylbenzenesulfonate and 944 g of water, and 1 kg of water, 25% by weight aqueous solution of potassium dresinate (avietta, Gerstofen, Germany) A mixture of 1.98 kg of Dresinat 214 K and 480 g of an 9.5 wt% Proxel XL2 aqueous mixture from Abieta Chemie GmbH was incorporated into the total amount of the polymer aqueous dispersion LI obtained as a protection against aging. .

220 g of the resulting aqueous composition was removed and the pH was adjusted to 9 with concentrated ammonia water and the following components were added:

2 g of a mixture of 625 g of water, 125 g of K-scriptset and 250 g of 10% by weight aqueous potassium hydroxide solution,

10 g of a 10% by weight aqueous solution of the Na salt of a naphthalenesulfonic acid condensate corresponding to tamol NN 4501 of relative number average molecular weight 6500,

7 g of an aqueous composition of finely divided ZnO consisting of 50 g of 45% by weight aqueous solution of Na salt of naphthalenesulfonic acid condensate corresponding to 1000 g of ZnO, 10 g of collagen AS / RK, tamol NN 4501, and 910 g of water,

1.6 g of an aqueous composition of finely divided sulfur consisting of 910 g of water, 60 g of a 45% by weight aqueous solution of Na salt of the naphthalenesulfonic acid condensate corresponding to tamol NN 4501, 30 g of collagen AS / RK and 1000 g of sulfur,

Of finely divided zinc mercaptobenzothiazole consisting of 50 g of 45% by weight aqueous solution of Na salt of naphthalenesulfonic acid condensate corresponding to 940 g of water, 1000 g of zinc mercaptobenzothiazole, tamor NN 4501 and 10 g of collagen AS / RK. 1 g of an aqueous composition, and

Finely divided zinc N- consisting of 50 g of 45 wt% aqueous solution of Na salt of naphthalenesulfonic acid condensate corresponding to 940 g of water, 1000 g of zinc N-diethyldithiocarbamate, tampon NN 4501 and 10 g of collagen AS / RK. 1 g of an aqueous composition of diethyldithiocarbamate.

This composition was then diluted to 40% by weight solids and left at 25 ° C. for 24 hours (aging). Then, a mixture of 1.8 g of water and 0.2 g of bazensol HA 5 was added for heat sensitization, and aging was continued at 25 ° C. for 24 hours. The resulting solidification temperature was 44 ° C.

VLT I: As with LT I, no Barzensol HA 5 was added.

LT II: As an anti-aging agent, 46.2 g of hydroxylamine sulfate, 4.6 g of Na dodecylbenzenesulfonate, 1.60 kg of water, 924 g of 50% by weight Naugawhite aqueous mixture and 370 g of 9.5% by weight Proxel XL2 aqueous mixture were obtained. It was incorporated into the total amount of the polymer aqueous dispersion L II. 215 g of the resulting aqueous composition was removed and the polymer aqueous dispersion L I containing the added anti-aging agent was formulated correspondingly in the same way as the LT I was obtained.

However, the aqueous ZnO composition added only 2 g instead of 7 g. In addition, the aqueous sulfur composition added 2 g instead of 1.6 g. Moreover, the amount of added bazensol HA 5 was 0.8 g (dissolved in 7.2 g of water) instead of 0.2 g and diluted to 25% by weight solids. The resulting solidification temperature was 41 ° C.

VLT II: As with LT II, no Vazolol HA 5 was added.

LT III: As with LT II, the amount of bazensol HA 5 added was 0.9 g (dissolved in 8.1 g of water). In addition, only 1 g of aqueous sulfur composition and 5 g of aqueous ZnO composition were added. After dilution with 25 wt% solids, the solidification temperature was 42 ° C.

VLT III: As with LT III, no Barzenol HA 5 was added.

C) Preparation of Immersion Products

The immersion type used was 70 ° C. and only three different ceramic cylinders (diameter 10 cm, length 28 cm, immersion depth 16 cm) in that KH2 and KH3 had an adsorbed surface layer of Ca (NO ₃ ) ₂ , VKH1, KH2 and KH3, which were used as follows:

KH2: The clean ceramic cylinder was first heated to 70 ° C., then immersed in a solution of 350 g of calcium nitrate, 639 g of water, 10 g of glacial acetic acid and 1 g of lutensol AP at an immersion rate of 100 mm / sec and left for 0.1 s. The immersion type was then removed (speed of 20 mm / sec) and dried at 70 ° C. for 180 seconds.

KH3: The calcium nitrate solution was performed as in KH2 except that 130 g of calcium nitrate, 639 g of water, 10 g of glacial acetic acid and 10 g of lutensol AP 10 were used.

Furthermore, the immersed VKH1, KH2 and KH3 were immersed in an aqueous latex immersion composition at 25 ° C. (for pure thermal coagulation, the immersion rate is 50 mm / sec and removal rate is 65 mm / sec, otherwise the parameters are 65 mm / sec and 10 mm / sec, respectively). After a limited residence time, the submerged form was removed again and left at 25 ° C. for 5 minutes.

The immersion type with the film deposited during the immersion process was then immersed in water at 40 ° C. for 5 minutes for film cleaning. It was then dried at 70 ° C. for 30 minutes and then vulcanized at 120 ° C. for 30 minutes (in each case in air at the appropriate temperature). The formed film was then peeled off and the specimens removed therefrom (type 2 according to ISO 37: 1994 (E)) were analyzed at a temperature of 23 ° C. and 50% relative ambient humidity (according to ISO 37: 1994 (E), Film thickness FD measured in μm; tension ZK (mPa) required for elongation of 100%, 200%, 300% and 500%, standardized tear strength, standardized for products of width and thickness of test location RK (mPa) and fracture elongation RD (measurement of increase in specimen length, in%, until tearing to initial length). The results obtained are shown in Tables 3 to 5 below.

Immersion type Latex immersion composition Residence time FD ZK100 ZK200 ZK300 ZK500 RK RD KH2 ¹⁾ LT II 10 sec 162 1.73 2.52 3.59 9.97 22.06 590 KH2 ¹⁾ VLT II 10 sec 105 1.74 2.54 3.57 8.85 22.35 616 VKH1 ²⁾ LT II 3 sec 117 1.02 1.29 1.56 2.53 10.17 727 KH2 ¹⁾ LT III 10 sec 181 1.99 3.05 4.55 13.76 25.79 567 KH2 ¹⁾ VLT III 10 sec 110 1.97 3.08 4.58 13.45 23.63 563 VKH1 ²⁾ LT III 3 sec 124 1.26 1.63 2.06 4.12 16.31 681 1) Using a novel method compared to pure electrolyte coagulation, a film with substantially the same properties but increased by at least 50% in thickness with the same residence time was obtained. 2) Using pure thermal coagulation, the mechanical properties of the resulting film The characteristic was unsatisfactory.

Immersion type Latex immersion composition Residence time FD KH3 LT III 10 sec 153 KH3 VLT III 10 sec 92

Immersion type Latex immersion composition Residence time FD RK KH2 LT I 10 sec 178 45.23 KH2 VLT I 10 sec 140 46.55 KH1 LT I 3 sec 204 37.39

Claims (24)

Process for free radical aqueous emulsion polymerization of monomers containing at least one ethylenically unsaturated group and at least 30% by weight having two ethylenically unsaturated conjugated double bonds at a temperature T at which the electrolyte is adsorbed onto the surface as a coagulant The immersion type is immersed into the aqueous emulsion immersion composition to which the components of Table 2 are added based on the weight of the dispersed polymer, including the polymer aqueous dispersion obtained by Provided that the electrolyte adsorbed on the immersed surface is Bronsted acid and / or salt, Free radical aqueous emulsion polymerization takes place in the presence of a dispersant of at least 50% by weight consisting of a water-soluble alkali metal salt and / or ammonium salt of monosulfonic acid of C ₁₀ -C ₂₀ hydrocarbons, The aqueous latex dipping composition is an added thermal coagulant comprising a nonionic organosilicon surfactant containing a polyether group and having a cloud point of 20 to 60 ° C., -Temperature T is higher than the cloud point of the organosilicon surfactant Method of making the immersed product. TABLE 2 weight% ingredient 0.25 to 2.5 sulfur 0.25 to 10 Zinc oxide 0.5 to 1.5 Vulcanization Accelerator 0.5 to 1.0 Anti aging agents 0 to 10 Insoluble Inorganic Filler 0 to 1.5 coloring agent 0 to 10 Plasticizer The method according to claim 1, wherein the cloud point of the added organosilicon surfactant is 30 to 40 ° C. The method according to claim 1 or 2, wherein the temperature T is between 40 ° C and 150 ° C. The method according to any one of claims 1 to 3, wherein the temperature T is 60 to 90 ° C. The process of claim 1, wherein the free radical aqueous emulsion polymerization is at least 75% by weight in the presence of a dispersant consisting of a water-soluble alkali metal salt and / or ammonium salt of monosulfonic acid of a C ₁₀ -C ₂₀ hydrocarbon. How it happens. The process according to claim 1, wherein the free radical aqueous emulsion polymerization takes place in the presence of a dispersant consisting solely of water-soluble alkali metal salts and / or ammonium salts of monosulfonic acids of C ₁₀ -C ₂₀ hydrocarbons. The process according to claim 1, wherein C ₁₀ -C ₁₃ -alkylbenzenesulfonate is used as at least one alkali metal salt and / or ammonium salt of monosulfonic acid of C ₁₀ -C ₂₀ hydrocarbon. The process according to claim 1, wherein C ₁₃ -C ₁₈ -alkanesulfonate is used as at least one alkali metal salt and / or ammonium salt of monosulfonic acid of C ₁₀ -C ₂₀ hydrocarbons. The method according to claim 1, wherein the Basensol HA 5 is used as a nonionic organosilicon surfactant containing a polyether group. The method according to claim 1, wherein Coagulant WS is used as a nonionic organosilicon surfactant containing a polyether group. The method according to claim 1, wherein the weight average diameter of the dispersed polymer particles is 80 to 300 nm. The process according to claim 1, wherein the weight average diameter of the dispersed polymer particles is between 100 and 200 nm. The process according to claim 1, wherein the weight average diameter of the dispersed polymer particles is between 100 and 200 nm. The method according to any one of claims 1 to 13, wherein the polymer aqueous dispersion 30 to 100% by weight of one or more monomers (monomer A) having two ethylenically unsaturated conjugated groups, 0 to 10% by weight of at least one monoethylenically unsaturated monomer (monomer B), wherein the molar solubility in water at 25 ° C. and 1 atmosphere is greater than the corresponding molar solubility in acrylonitrile, and 0 to 70% by weight of at least one monoethylenically unsaturated monomer (monomer C), wherein the molar solubility in water at 25 ° C. and 1 atmosphere is not greater than the corresponding molar solubility in acrylonitrile. The method obtained by the free radical aqueous emulsion polymerization method of the monomer mixture of. 15. The method of claim 14 wherein monomer A comprises at least one monomer from the group consisting of butadiene, 2-methylbutadiene, 2,3-dimethylbutadiene, 1,3-pentadiene and 2,4-pentadiene Way. The method according to claim 14 or 15, wherein the monomer B used is an α, β-monoethylenically unsaturated C ₃ -C ₆ mono- and dicarboxylic acid, salts thereof, amides thereof, vinylsulfonic acid, salts thereof, And one or more monomers from the group consisting of N-vinylpyrrolidone. 17. The monomer C according to any one of claims 14 to 16, wherein the monomers C used are styrene, vinyltoluene, o-chlorostyrene, acrylonitrile, methacrylonitrile, acrylic acid or methacrylic acid and C ₁ -C ₈ alkanols. At least one monomer from the group consisting of esters of 18. The process of any of claims 14 to 17, wherein butadiene is used only as monomer A. The process according to claim 14, wherein methacrylic acid is used only as monomer B. 19. 20. The process of any of claims 14-19, wherein acrylonitrile or styrene is used as monomer C. The composition of any of claims 14 to 20, wherein the composition of the monomer mixture polymerized by the free radical aqueous emulsion polymerization method is 30 to 90% by weight of monomer A, 1 to 10% by weight of monomer B and 9 to 60% by weight of monomer C. How to be. 22. The composition of any of claims 14 to 21, wherein the composition of the monomer mixture polymerized by the free radical aqueous emulsion polymerization method is 45 to 70% by weight of monomer A, 3 to 10% by weight of monomer B and 27 to 45% by weight of monomer C. How to be. 23. The method of claim 22 wherein monomer A is butadiene, monomer B is methacrylic acid and monomer C is acrylonitrile. 24. The transversal nuclear magnetic relaxation time of any of claims 14 to 23, wherein the film of the polymer aqueous dispersion obtained in the course of free radical aqueous emulsion polymerization, of the protons chemically bonded to the polymer ( ^{1 H} T ₂ ) is 2.5 to 4.5 ms.