FI62108B - FOERFARANDE FOER FRAMSTAELLNING AV EN KATJONISK LATEX BESTAOENDE AV PARTIKLAR MED EN VISS STRUCTUR OCH EN VATTENHALTIG KOLLOIDDispERSION AV LATEXEN - Google Patents

Description

r, ANNOUNCEMENT

MA [BJ (11) UTLÄGGNINGSSKRIFT 6210 8 5¾¾ c Patent -yönnftty 10 11 1932 (^ 5) Patent ceddelat ^ y ^ (51) K ».lk? /Lnt.CI.3 C 08 P 291/04 FINLAND —FINLAND ( 21) Putunttlhtkutnu · - PttenttnrtMmln * Τ6ΐθ8ΐ (22) Htkumtopilvl — AMOknlngfdtf 21.OU.76 (23) AikupUvt — Gltclfh «ud * f 21.0it.76 (41) Tuikit Julkbuktl - BWvit offuntllg 22.10.76

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Patent · och registrarstyralsan '' AmMuo utltgd och utl. * Krift «n pubiic * r * <i 30.07.82 (32) (33) (31) Pn" »*« r Utuelkeu * - B.glrd prlorltM 21. ol. 75 21.01.75 USA 569723, 56'972l (71) The Dow Chemical Company, -2030 Abbott Road, Midland, Michigan, USA (72) Dale Sabin Gibbs, Midland, Michigan, Earl Henry Wagener, Contra Costa, California, Ritchie Antone Wessling, Midland, Michigan, USA (7l) 0y Roister Ab (5I) Process for the preparation of a cationic latex composed of certain structural particles, and an aqueous colloidal dispersion of the latex - The present invention relates to a process for the preparation of a latex consisting of cationic particles of a certain structural structure and to an aqueous colloidal dispersion of the latex. at or near it.

Latexes require some means to achieve colloidal stabilization in aqueous media. The usual colloidal stabilization is achieved with surfactants which are usually anionic or cationic, but may be non-ionic, especially in mixtures of anionic or cationic surfactants. Although surfactants contribute to the required colloidal stability, they can interfere with the coating performance of latexes, although the amount is limited and less stability than required is obtained. Another method is to copolymerize 2,626,108 nonionic monomers with a small amount of ionic monomer to produce a stable latex with little or no conventional surfactant, as described in U.S. Patent No. 3,637,432. However, such processes require special combinations of monomers and special polymerization techniques. Although such processes produce latices with little or no surfactants, varying amounts of water-soluble products are formed during the process and remain in the product.

U.S. Patent No. 3,236,820 describes the reaction of anionic latices of vinylbenzyl chloride polymers with sulfides to produce water-soluble cationic polymers. Starting from the anionic emulsion, the conversion of polymerized vinylbenzyl chloride units on the surface of the particle to cationic groups causes destabilization of the latex. If the number of vinylbenzyl chloride units in the polymer is not large enough to make the polymer in a water-soluble converted form, the latex will coagulate.

According to the present invention, a latex is prepared having particles of a certain structure consisting of a water-insoluble, non-ionic, organic polymer backbone encapsulated in a thin layer of a copolymer having chemically bonded pH-independent cationic groups, said structural particles having bound particles on or near the outer surface. In the process of the invention, at a temperature of 0 to 80 ° C, a latex of copolymer particles chemically bonded to activated halogen atoms is reacted with (B) a water-resistant, nonionic nucleophilic compound capable of diffusing through aqueous media. The process is characterized in that the latex (A) consists of (1) a nonionic organic polymer backbone having a thin layer polymerized on the surface of the particles of a water-insoluble ethylene-unsaturated monomer containing activated halogen atoms, or (2) a latex copolymer (a) an ethylenically unsaturated nonionic monomer containing no activated halogen atoms, and (b) an ethylenically unsaturated monomer containing activated halogen atoms, wherein the total number of activated halogen atoms in the latex (A) is 0.01 to 1.4 milliequivalents per gram of polymer and 0, 4-2.5 milliequivalents per gram of polymer in a thin layer 3 62108 on or near the surface of the latex particle, and wherein the latex (A) is prepared by emulsion polymerization at 0-80 ° C in the presence of a free radical catalyst and contains a small stabilizing amount of cationic surface -active compound or ka a mixture of a thionic surfactant and a nonionic surfactant, the amount of surfactant being less than that required to initiate new particles in the presence of additional monomers, and wherein the water-resistant nucleophilic compound (B) is (1) tetra- ( C 1 -C 4 alkyl), thiourea or a compound of formula (2) I (S) S, (3) (4) R 1 -R 2 R 3 P '(5) R'N or (6) P (3) wherein and R 3 is C 1 -C 4 alkyl and R 'is H or C 1 -C 4 alkyl, and wherein the pH-independent cation groups are chemically bonded to or in the vicinity of the copolymer particles to a sufficient extent to provide the bulk of the colloidal stability of the latex.

The invention further relates to an aqueous colloidal dispersion of a latex of cationic particles of a certain structure, consisting of a non-ionic organic polymer backbone encapsulated in a thin layer of a water-insoluble organic copolymer in which the organic copolymer is chemically bound to the surface of the particles. 0.01 to 0.5 milliequivalents per gram of latex copolymer and 0.4 to 2.5 milliequivalents per gram of thin film copolymer.

In one embodiment, the preparation of the products of this invention requires a starting latex containing solid polymer particles colloidally dispersed in water, the composition and method of preparation of which are known but then modified to encapsulate the starting latex particles with a copolymer of ethylenically unsaturated activated halogen. missing activated halogen. The resulting latex contains colloidally dispersed particles having reactive halogen groups on or near the surface of the particles. Such a -6,2108 latex can then be reacted with a low molecular weight, non-ionic, nucleophilic compound to form a latex having polymer particles having pH-independent cationic groups attached to the surface. The colloidal stability of the latex is improved in this way and other advantageous properties are obtained.

There are several known latexes that can serve as starting materials for the preparation of latexes containing activated halogen and their composition is not critical. Such latexes are prepared by methods well known in the art. Preformed latexes with substantially no residual monomers can be used, but preferably these starting latexes can be prepared by emulsion polymerization, which is the first step in the preparation of latex products in which some monomer and some free radicals remain at the time of addition of the activated halogen monomer. The starting latex or components and methods for preparing such a latex are selected from known latex preparations which are substantially free of anionic groups and / or union surfactants adsorbed or otherwise attached to the polymer particles contained in the latex. The latex is preferably mildly cationic, usually due to the presence of a pine amount of cationic surfactant. For best results, the starting latex should not contain an amount of surfactant sufficient to initiate new particles as additional monomer is fed. The composition of the polymer component of the starting text also affects certain properties of the final product, as it forms the major part of the total weight of the product. Thus, the selection is made to some extent in accordance with the desired polymeric properties that these prior art materials are known to have to replace the properties inherent in the encapsulation component of this invention. Thus, to describe, but not limit, the predominant portion of the products, a starting latex that is film-forming at room temperature is selected, but there are uses for which a non-film-forming starting latex would be selected, such as for plastic pigments. Usually the starting latices have a particle size of about 50-1000 nm, preferably about 80-300 nm. If the products are to be used in a manner that requires certain well-known properties, e.g. low electrolyte concentration, these properties must be considered when selecting the starting material and the ingredients to be used in the subsequent steps of the process. These choices are within the skill of the art and are not considered to be inventive aspects of the novel preparations and method described herein.

The starting latexes are typically obtained by emulsion polymerization of one or more monomers. Such monomers are represented by the same monomers listed below for copolymerization with activated halogen monomers.

Encapsulation starting latices may also consist essentially of polymers that are not readily prepared from monomers by emulsion polymerization, either because no substantial polymerization at a commercially acceptable rate is achieved under standard emulsion polymerization conditions, such as isobutene, or because the specific form of the polymerized monomer is desirable. stereospecific polybutadiene, etc. Typical preformed polymers include polymers and copolymers of monoolefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 2-butene, isobutene, pentene, hexene, octene, dodecene, , octadecene and in particular those monoolefins having up to 8 carbon atoms. Particularly common types are various ethylene / propylene copolymers.

Examples of still other polymers that may be components of the starting latex used for encapsulation include alkyd resins, block and graft copolymers; e.g. styrene / butadiene graft and block copolymers; epoxy resins such as reaction products of epichlorohydrin and bisphenol-A; and thermosetting vinyl ester resins: e.g., reaction products obtained from approximately equimolar amounts of polyepoxide and an unsaturated monocarboxylic acid such as acrylic and methacrylic acid or an unsaturated fatty acid such as oleic acid.

Methods for preparing the polymers described above and methods for converting polymers to latexes are well known.

In one process for obtaining a latex suitable for subsequent reaction according to the process of this invention, the starting latex particles are encapsulated in a thin layer by either adding a copolymer of ethylenically unsaturated activated halogen monomer to the polymerized compound or a mixture of such monomers. a halogen monomer together with one or more hydrophobic monomers to a starting latex which contains substantially no residual monomers and by initiating and continuing to polymerize the monomers thus added until substantially complete conversion. Other latices suitable for the reaction of the process of the invention can be obtained by direct emulsion polymerization of an ethylenically unsaturated activated halogen monomer and an ethylenically unsaturated, nonionic monomer having no activated halogen. In this case, latices are obtained which contain particles of a copolymer with activated halogens evenly or randomly distributed throughout the particles.

Activated halogen monomers for both types of latex must be sufficiently activated to react at a reasonable rate with nucleophilic substances subsequently added after polymerization, but not so reactive as to be readily hydrolyzed in an aqueous medium. Such suitable monomers include ethylenically unsaturated benzyl chloride and bromide monomers, ethylenically unsaturated aliphatic bromide monomers, and ethylenically unsaturated aliphatic iodide monomers. Particularly preferred activated halogen monomers are vinylbenzyl chloride, vinylbenzyl bromide, 2-chloromethylbutadiene, vinyl bromide and bromoalkyl acrylate or bromoalkyl methacrylate, especially 2-bromoethyl acrylate or 2-bromoethyl.

The activated halogen monomers are oil-soluble, easy to polymerize in an emulsion, do not inhibit free radical polymerization, and diffuse at a satisfactory rate through the aqueous medium of the latex to the latex particle.

The hydrophobic, ethylenically unsaturated monomer that can be copolymerized with the activated halogen monomer can be selected from a known large number of nonionic. ethylenically unsaturated monomers that are polymerizable in an aqueous emulsion to form a water-insoluble polymer. These monomers are well known in the art and are therefore described below by only 7,610,108 typical examples. The non-ionic. hydrocarbon monomers representing ethylenically unsaturated monomers, such as styrene compounds, e.g., styrene, o-methylstyrene, ar-methylstyrene, ar-ethylstyrene, oC, ar-dimethylstyrene, ar, ar-dimethylstyrene and t-butylstyrene; conjugated dienes such as butadiene and isoprene; hydrocarbon monomers modified with non-ionic substituents, e.g. hydroxystyrene, methoxystyrene and cyanostyrene; unsaturated alcohol esters such as vinyl acetate and vinyl propionate; unsaturated ketones, e.g. vinyl methyl ketone and methyl isopropenyl ketone; unsaturated ethers, e.g. vinyl ether and vinyl methyl ether; and nonionic derivatives of ethylenically unsaturated carboxylic acids such as acrylic esters, e.g. methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate and lauryl acrylate; methacrylic esters, e.g. methyl methacrylate, ethyl methacrylate; maleic esters such as dimethyl maleate, diethyl maleate and dibutyl maleate; fumaric esters, e.g. dimethyl fumarate, diethyl fumarate and dibutyl fumarate and itacone esters, e.g. dimethyl itaconate, diethyl itaconate and dibutyl itaconate; and nitriles, e.g., but not limited to, acrylonitrile and methacrylonitrile. Nonionic: Monomers containing halogens that are not activated, such as monochlorostyrene, dichlorostyrene, vinyl fluoride, and chloroprene, may be used, although they do not fall into the preferred category. Also, nonionic monomers that form water-soluble homopolymers, e.g., acrylamide, methacrylamide, hydroxyethyl acrylate, and hydroxyethyl methacrylate, can be blended into the hydrophobic monomer in small amounts up to about 10% based on the amount of hydrophobic monomer.

By the phrase "pH-independent groups" when applied to ionic groups is meant that the groups are mainly in ionized form over a wide pH range, e.g. between 2-12.

By "non-ionic" in this context is meant that the monomers are not ionic as such or do not become ionic by a simple change in pH. For example, although the monomer containing the amine group is nonionic at high pH, the addition of a water-soluble acid lowers the pH and forms a water-soluble salt; therefore, such a monomer is not included.

8 62108

When carrying out the polymerization of an activated halogen monomer in those embodiments where it is desirable not to introduce activated halogens into the particle, the ratio of monomer to total polymer in the latex must be kept low at any given time during the process to avoid unduly swelling of existing latex particles. When the expansion is too large, i.e. when too much monomer is dissolved in the polymer, some polymerization may occur within the particle.

When this happens, the reactive halogens are buried in the particle. The activated halogen monomer is added to the starting latex over a short period of time or added as a batch in one or more portions. Optionally but preferably, a hydrophobic monomer lacking activated halogen, or a mixture of such monomers, is usually added to the activated halogen monomer. The polymerization is preferably carried out at such a low temperature that it provides a practical polymerization rate to avoid hydrolysis of the activated halogen monomer. Such temperatures range from about Q-8 ° C, and preferably from about 50-70 ° C. If the starting latex is not prepared in the reaction mixture itself, an initiator system (catalyst) is added to activate the surface of the latex particle, i. to achieve a steady state concentration of free radicals. If desired, the addition of the initiator system can be continued after the addition of the monomers - especially when an oxidation-reduction system is used. The polymerization reaction is continued until the monomers are substantially completely copolymerized.

The product obtained by the method described above is a latex in which colloidally dispersed polymer particles with a particle size of about 50-100 nm form starting latex particles encapsulated in a bonded layer of varying thickness from a copolymer monomolecular layer to about 10 nm. a functional polymer having activated halogen groups on the outer surface.

The amount of activated halogen monomer copolymerized in the encapsulation layer of a particular latex of structured particles in gears ·. * Ranges from about 0.01 to 1.4 milliequivalents, and preferably from about 0.04 to 0.5 milliequivalents per gram of total polymer in the latex. However, there must be a sufficient amount of hydrophobic monomer copolymerized with the activated halogen monomer so that each in the encapsulation layer, i.e. there is a maximum of 3.0 milliequivalents of copolymerized activated halogen monomer per gram of polymer in the coating. The amount of activated halogen monomer is inversely proportional to the particle size of the latex to be encapsulated and also inversely proportional to the cross-sectional area of the activated halogen monomer molecule. Thus, a minimum amount of activated halogen monomer would not be used with the smallest particle size starting latex.

The initiators used in the polymerization of activated halogen monomers are of the type which produce free radicals and are preferably peroxygen compounds, e.g. inorganic peroxides such as hydrogen peroxide; organic hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide; organic peroxides such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, peracetic acid and perbenzoic acid - sometimes activated with water-soluble reducing agents such as ferro compound, ferric compound, sodium bisulphite or hydroxylamine hydrochlorides - and other free radicals - and other free radicals

Organic hydroperoxides and 2,2'-azobisisobutyronitrile are recommended.

Surfactants used either in the starting latex or as additives to further stabilize the latex products are cationic or nonionic surfactants or mixtures thereof.

Cationic surfactants include classes consisting of salts of aliphatic amines, especially fatty amines, quaternary ammonium salts and hydrates, fatty amides derived from disubstituted diamines, isothionylated amide derivatives, fatty chain derivatives of pyridinium compounds, fatty chain derivatives of pyridinium compounds compounds and phosphonium compounds. Typical examples of the cation lashing surfactants are dodecylamine acetate, dodecylamine hydrochloride, tetradekyyliamiinihydrokloridi, hexadecimal-Hyyliamiiniasetaatti, lauryylidimetyyliamiinisitraatti, octadec-yl-amine sulphate, dodekyyliamiinilaktaatti, cetyl trimethylammonium bromide, cetylpyridinium chloride, etanoloitu alkyyliguanidiini- 62108 ίο amine complex, stearyl, cetyl dimethylamine oxide, setyylidimetyylibentsyyliammoniumkloridi , tetradecylpyridinium bromide, diisobutylphenoxyethoxyethyl dimethylbenzylammonium chloride, 1- (2-hydroxyethyl) -2- (mixture of pentadecyl and heptadecyl) -2-imidazoline, resin-amylisecylate, octylisethylate hydroxyethylsulfonium acetate, dodecylbenzyldimethylsulfonium chloride, dodecylbenzyltrimethylphosphonium chloride, Sp-dodecylbenzyl-N, N, N1, N1 -tetramethylisourium chloro ridi etc.

Typical nonionic emulsifiers (surfactants) are compounds formed by the reaction of an alkylene oxide such as ethylene oxide, propylene oxide or butylene oxide with long chain fatty alcohols, long chain fatty acids, alkylated phenols, long chain alkyl mercaptans, long chain alkyl mercaptans. , when the alkylene oxides are reacted in a ratio of 5 to 20 moles or more, such as up to 50 moles per mole of the second reagent. Similarly effective compounds are monoesters such as the reaction products of polyethylene glycol and a long chain fatty acid, e.g. glycerol monostearate, sorbitan trioleate and the partial and full esters of long chain carboxylic acids which they form with polyglycol ethers of polyhydric alcohols. "Long chain" in the above description usually means an aliphatic group having 6 to 20 carbon atoms or more.

Preferred surfactants are those having pH-independent cationic groups, and weak surfactants such as cationic surfactants in which the cationic group is a sulfonium, sulfoxonium isothiouronium or reducing quaternary nitrogen group are particularly preferred. , e.g. a pyridinium, isoquinolinium and quinolinium group.

The latex of the above description, comprising the starting latex particles encapsulated in a relatively thin layer of a copolymer of activated halogen monomer and hydrophobic ethylenically unsaturated monomer, can then be reacted with a low molecular weight, nonionic, water-stable, water-stable, nucleophilic nucleophilic compound. through the phase of n 62108, to form polymer particles with pH-independent cationic groups, i. onium ions chemically attached to the surface of the particle. Usually the particles are approximately spherical.

Alternatively, a latex of a copolymer having activated halogens evenly or randomly distributed on the polymer particles forming the entire latex may be reacted with a nonionic nucleophilic agent to produce a cationic latex of a certain structural structure, provided that the compositions and conditions are activated halogens in the vicinity react with the nucleophilic substance. The amount of activated halogen in such copolymers should not exceed about 3 milliequivalents / g. Because the reaction rate of activated halogens on or near the surface of the particle in such copolymers is significantly higher than that of halogens within the particle, the kinetic data indicate when a thin layer near the surface has reacted. Copolymers in which larger amounts of activated halogen monomer are polymerized throughout the particle cause the particle to swell upon reaction with the nucleophilic substance, further reaction within the particle can occur quite easily, control of the reaction to achieve a particular structured particle is difficult and the same advantageous results are not obtained.

For each active halogen reacted with the nonionic nucleophilic substance, one polymer-bound charge is formed and one halide ion is released. In the reaction of a nucleophilic substance with activated halogen, a certain latex of structured particles, or a latex having activated halogens distributed throughout the latex particle, the amount of halogen reacted is such as to provide a charge of about 0.01 to 0.5 milliequivalents per gram of polymer. Preferably, the range is from about 0.04 to 0.35 milliequivalents per gram of polymer. However, in the thin reacted layer near the surface of the particle, the amount of charged charge is about 0.04-2.5 milliequivalents for each gram of polymer in the layer.

Nucleophilic compounds useful in the practice of this invention are carbon-containing nucleophiles of 4i-ionic, stable in aqueous media and capable of diffusing therethrough, having a heteroatom as a nucleophilic autumn center, in which all carbon atoms of said heteroatom are .

The nucleophilic compounds preferably used in the practice of this invention are represented by the following classes of compounds, which are sometimes referred to as Lewis bases: (a) monobasic aromatic nitrogen compounds, (b) tetraC lower alkyl) thioureas, (c) R 1 -S-R 2 compounds. , wherein and R 2 are independently lower alkyl or hydroxy-lower alkyl groups, or wherein R 1 and R 2 are joined to form one alkylene radical having 3 to 5 carbon atoms.

(d) R 1 -N-R 2 compounds * 3 wherein R 2 and R 2 are independently lower alkyl or hydroxy-lower alkyl groups or are joined to a single alkylene radical of 3 to 5 carbon atoms and R 1 is lower alkyl, aralkyl or an aryl group except when R 2 and R 2 together are an alkylene radical, wherein R 1 is a lower alkyl or hydroxy-lower alkyl group and (e) R 1 -PR 4 compounds wherein R 1, R 2 and R 2 are independently lower alkyl -, hydroxy-lower alkyl or aryl groups.

In this context, the term lower alkyl group means an alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl and isobutyl groups.

Representative nucleophilic compounds of the group include pyridine, quinoline, isoquinoline, teramethylthiourea, tetraethylthiourea, hydroxyethylmethylsulfide, hydroxyethylethylsulfide, dimethylsulfidyldisulfide, propylsulfyl, di-n-propylsulfide, methyl-n-diiside trimethylene sulfide, thiacyclohexane, tetrahydrothiophene, N-methylpiperidine, N-ethylpyrrolidine, N-hydroxyethylpyrrolidine, trimethylphosphine, triethylphosphine, tri-n-butylphosphine, triphenylphosphine, triethylamine, triethylamine, triethylamine, triethylamine hydroxyethyldimethylamine, butyldimethylamine, trihydroxyethylamine, triphenylphosphorus and Ν, Ν, Ν-dimethylphenethylamide.

When carrying out the reaction between a nucleophilic compound and latex particles chemically bound to activated halogens, the latex is gently mixed while the nucleophilic compound is added to it either as a compound or as a solution. Gentle stirring may be continued throughout the subsequent reaction or, optionally, after the compound has been dispersed in the latex, stirring may be stopped. The reaction is most conveniently carried out at ambient temperature, even at temperatures between 0 and n. 80 ° C can be used. The reaction itself occurs at a rate that depends on the reactivity of the activated halogen and nucleophile. It is recommended to carry out the reaction until most of the colloidal stability of the product has been achieved with the resulting chemically bonded cationic groups. Usually no catalyst is needed, although a small amount of iodide ion can be used with less reactive substances to facilitate the reaction. Once the desired degree of reaction has been achieved, any excess nucleophile is generally removed by standard methods, e.g., dialysis, vacuum stripping, and steam distillation.

Other pH-independent cationic groups can be substituted for cationic groups chemically bonded to the latex particles as described above by further reaction with these cationic groups. For example, a cationic latex of certain structured particles in which the sulfonium groups are chemically bonded to or near the surface of the structural particles may be reacted with hydrogen peroxide at a temperature between about 20-80 ° C, preferably at ambient temperature for sufficient time to partially or completely oxidize the sulfonium groups . Such treatment also reduces the odor of the latex. To best achieve results in such an oxidation reaction, an excess of hydrogen peroxide is used, e.g., 2-10 moles of hydrogen peroxide per mole of sulfonium groups.

When the products are to be used in metal coating, it is recommended to react an activated halogen latex containing only as much activated halogen as desired to convert 1 62108 m to a bound charge, the activated halogens are then completely converted to cationic groups and the product no longer contains any bound halogen.

The cationic latices of this invention have significantly improved chemical and mechanical stability. However, in many applications, such as coating hydrophobic substrates with latices stabilized only on the surface of the particle by chemically bound charges, there is too much surface tension to provide good wetting of the hydrophobic surface. In these cases, it is preferred to add small amounts to the latex, such as about 0.01 to 0.1 milliequivalents / g of polymer of a conventional cationic or nonionic surfactant. Instead, in other applications, the presence of even small amounts of water-soluble surfactants is detrimental. The latexes of this invention are highly preferred for such applications. Because a sufficient amount of charge is chemically bound to the surface of the particle to provide colloidal stability, complete dialysis or ion exchange can be used, if desired, to remove water-soluble material from the latex and replace counterions while maintaining latex cationic functionality and colloidal stability.

A simple test is suitable for screening latexes for shear-stress stability: a drop of latex is placed on the palm and rubbed back and forth with the finger. As the latex is cut, it gradually dries and forms a film. Unstable latexes coagulate before drying, usually after 1-3 abrasions. Stable latices can be rubbed more than 5 times before they break down. Latexes, which withstand 20 abrasions, are very stable and can be rubbed to dryness before they harden.

The friction test is proportional to the advanced test in which a drop of latex is ground in a cone-plate viscometer (Rotovisco rotary viscometer). According to the rubbing test, a very stable latex can be ground for more than 15 minutes at 194 rpm without coagulation of the latex.

The latices of this invention, i. the particles of the starting latexes and products are generally approximately spherical in shape and have a particle size (diameter) of about 50-1000 nm.

v. The following examples illustrate ways in which this invention may be practiced.

15 62108

All parts and percentages are by weight unless otherwise indicated. The particle sizes shown in the examples are average particle diameters obtained by light scattering measurements unless otherwise indicated.

Example I

A thermoplastic acrylic latex is prepared as follows. A monomer mixture is prepared from 1072 grams of ethyl acrylate and 528 g of methyl methacrylate, and to this mixture are added 24 g of dodecane thiol and 5 g of an 82.7% t-butyl hydroperoxide solution to form a monomer feed solution. A seed latex is prepared from 750 g of a surfactant solution previously prepared by mixing together 710 g of water and 40.0 g of a 25% active solution of dodecylbenzyldimethylsulfonium chloride for 2 hours in a stream of nitrogen, to which is then added 25 g of monomer feed solution followed by continuous addition. a stream pumped for about 2 hours at a rate of 7.67 g / h, this flow being part of a solution previously prepared from 9 grams of hydroxylamine hydrochloride diluted to 50 g with deionized water. A monomer feed solution is added to the seed latex at a rate of 55 g / h while continuing to add a reducing flow at the same rate and composition as the seed latex and at the same time a 20 g / h surfactant solution previously prepared from 400 g of deionized water and 100 g of dodec is pumped into the reaction mixture. -cyldimethylsulfonium chloride 25% active solution. After 20 hours, the conversion is about 85%, the continuous additions are stopped, 15 g of vinylbenzyl chloride are added and the reaction is allowed to continue for another 2 hours. The temperature is maintained at 50 ° C throughout the reaction. In this way, a latex (C-1) with a dry matter content of 47.6%, a pH of 2.8, a particle size of 125 nm and a polymer having a molecular weight of 74,000 with a chloride ion content of 0.113 milliequivalents per gram of polymer is obtained.

A portion of the latex (C-1) is diluted with water to a dry matter content of 23.8%, 2.12 parts of trimethylamine per 100 parts of the diluted latex are then added with gentle stirring and the resulting mixture is allowed to stand at room temperature for 5 hours. A latex (I-A) is obtained containing 0.242 milliequivalents of total charge per gram of polymer, of which 0.129 milliequivalents are present from the quaternary 16 62108 ammonium groups bound to each gram of polymer in the latex.

Another portion of latex C-1 is treated as described in Example 2 except that trimethylamine is replaced with 2.24 parts of dimethyl sulfide. A latex (I-B) is obtained containing 0.237 milliequivalents of total charge per gram of polymer, of which 0.124 milliequivalents are present from the sulfonium groups bound to each gram of polymer in the latex.

Example II

Latexes are prepared by the semi-continuous method as described below. Different compositions are prepared for addition in separate streams.

Aqueous solution 8.75 g of an 85.5% aqueous solution of phosphoric acid 1000 g of water enough ammonium hydroxide to adjust the pH of the above solution to 5.0 20 g of (active) dodecylbenzyldimethylsulfonium chloride enough water 2000 g of solution enough to adjust the pH to 5 , 0. Continuous emulsifier stream 125 g of (active) dodecylbenzyldimethylsulfonium chloride in sufficient water. To 1000 g of an aqueous solution containing 125 g of (active) dodecylbenzyldimethylsulfonium chloride.

Continuous initiator stream 500 g of an aqueous solution containing 27.5 g of (active) t-butyl hydroperoxide

Continuous stream of reducing agent 500 g of an aqueous solution containing 14 g of hydroxylamine hydrochloride

First monomer solution 1500 g butadiene 1200 g styrene 300 g butyl acrylate 3 g dodecanethiol (chain transfer agent).

17,621 08

Second monomer solution 250 g butyl acrylate 50 g vinylbenzyl chloride 3 g dodecanethiol

Process

The starting aqueous solution is placed in a 7.57 dm ^ P f audl ear reactor equipped with a paw stirrer and the partially filled reactor is purged four times with nitrogen, then 100 g of the first monomer solution are added, the pressure in the reactor is raised to 240 kPa with nitrogen and the temperature is raised to 50 ° C. A continuous initiator stream and a continuous reducing agent stream are initiated, both at a rate of 10 g / h.

After this addition has taken place for three hours with stirring (at a stirrer speed of 235 rpm), the monomer solution and the continuous emulsifier stream are pumped into the reactor at 40 and 110 g / h, respectively, for 19 hours. A constant flow of initiator, a continuous stream of reducing agent and a continuous flow of emulsifier are maintained while the second monomer solution is fed at a rate of 50 g / h for 3 hours. Continuous initiator flow, continuous reducing agent flow, stirring and maintaining the polymerization temperature at 50 ° C are continued for another 45 minutes. A latex (C-2) with 40.4% dry matter and a particle size of about 112 nm is obtained.

Prepare a second latex as described for latex C-2 except that the first monomer solution is added for 20 hours instead of 19 hours, the second monomer solution is not added and the continuous initiator stream and continuous reducing agent stream and stirring and 50 ° C reaction temperature are continued for four hours after the first monomer solution feed. . A latex C-3 (not an example of the invention) with a dry matter content of 39.2% and a particle size of 111.5 nnii is obtained. A portion of the dodecylbenzyldimethylsulfonium chloride is sufficiently mixed with a portion of the latex to give an additional 0.09 milliequivalents of sulfonium ion per gram of polymer in the latex and the pH is adjusted to 7.6 (latex C-3A).

To a portion of latex C-2 is added, with gentle stirring, dimethyl sulfide in an amount calculated to form an excess over the active halogen in the latex. The resulting mixture is allowed to stand at room temperature for about 16 hours. The latex (II-A) is steam distilled after this 62108 and is found to contain 0.05 milliequivalents of bound sulfonium cation per gram of polymer. A portion of latex II-A is diluted with water to a dry matter content of 10% and the pH is adjusted to 7.0. In the pump stability test, it is observed that only a small amount of coagulation is observed and very little change in viscosity has occurred when the test is stopped after 21 days. When the same test is performed on the control latex C-3A, it shows strong coagulation after 9 days. For the pumping test, 3000 ml of latex with a dry matter content of 10% are placed in a container of 3.79 dm. and pumped with a Teel centrifugal pump model 9M1M3 operating at 3000 rpm. Water is added from time to time to replace the water lost by evaporation, i. to maintain the same volume and concentration. Latex is monitored from time to time for destabilization. The test is stopped after coagulation is strong enough to block the pump or after 21 days, whichever occurs first.

Example III

Two latexes are prepared according to the recipe of Table I, which contain copolymers of vinylbenzyl chloride having the same composition but a different arrangement of polymerized vinylbenzyl chloride in the latex polymer particles.

Table I Recipe

Component Latex C-4 Latex C-5 parts_ _parts _

Water 300 200

Dodecylbenzyldimethylphenium chloride (soap) '1 1

Azobisisobutyronitrile (initiator) 2 - 2

Styrene 43 43

Butadiene 50 50 2-hydroxyethyl acrylate 2 2

Dodecanethiol (chain transfer agent)

Vinylbenzyl chloride 5 5 (a) (a) added at about 90% conversion of styrene, butadiene and hydroxyethyl acrylate.

19 3 62108

Latexes are prepared in a 7.57 dm glass-lined Pfaudler boiler equipped with a paw mixer. Water, soap, chain transfer agent and initiator are charged to the reactor at room temperature, the stirrer is started, the reactor is closed and the system is purged four times with nitrogen. The monomers (except vinylbenzyl chloride in latex C-5) are introduced into the reactor and the contents of the reactor are heated to 50 ° C and maintained at this temperature for 20 hours. The temperature is then raised to 70 ° C and the reaction is allowed to proceed at this temperature until the reactor pressure reaches a constant value. The resulting latex C-4 is cooled and removed from the reactor. In the case of latex C-5, the vinylbenzyl chloride monomer is added to the reactor at this stage and stirring at 70 ° C is continued for 2 hours. The product (latex C-5) is then cooled and removed from the reactor.

The analyzes of the products give the following results:

Table II

Latex Dry matter,% Particle size, nm Conversion,% C-4 22.7 132 90.8 C-5 30.5 134 95.5

Dodecylbenzyldimethylsulfonium chloride (based on the dry matter of the polymer) is added to each latex, after which both latexes are diluted with water to a dry matter content of 20%.

To one half of the diluted latex C-5 is added 4 moles of the nucleophilic compound, dimethyl sulfide, for each mole of polymerized vinylbenzyl chloride in the latex. The subsequent reaction is allowed to proceed at 30 ° C for the time shown in Table III to produce latex III-A. The other half of latex C-5 is treated in the same manner except that dimethyl sulfide is replaced by the same molar ratio of a different nucleophile, trimethylamine, to produce latex III-B. The other half of the latex C-4 is treated as described for latex III-A to produce a comparable latex C-4 A. The other half of latex C-4 is treated in the same manner as described for latex III-B to produce comparable latex C-4B. The conversion of the benzyl chloride group to the benzyl onium ion is determined by titration of the chloride ion with a solution of silver nitrate.

The results are shown in Table III.

20

Table III

62108 .a) Reaction time, Bound charge, milliekviv. / g

Latex Nucleophile 3J.i ^ polymer III-A DMS 120 0.22 III-B TMA 120 0.24 C-4A DMS 912 0.07 C-4B TMA 216 0.21 a) DMS * dimethyl sulfide TMA * · trimethylamine These results show that a comparable latex C-4, with a relatively uniform distribution of copolymerized vinylbenzyl chloride was converted more slowly and to a lesser extent than a latex of a certain number of structural particles, i. latex c-5.

Examples IV-XI

Prepare a series of latexes in the same way as latex C-5 with the following composition:

Percent Monomer 4 8-X Styrene 50 Butadiene 2 2-hydroxyethyl acrylate X Vinylbenzyl chloride

The resulting products in which X is 2.5 or 5.0 are sufficiently mixed with more dodecylbenzyldimethylsulfonium chloride to give a total concentration of 2% by weight, based on the polymer in the latex. Each latex is diluted with water to a dry matter content of 20%. Portions of each diluted latex are then reacted with the nucleophile by the procedure described in Example III for the time shown in Table IV to obtain products IV-XI. The conversion to onium ion is determined by titration of the chloride ion released in the reaction and the products are vacuum stripped before evaluation. The stability of latex products is evaluated by the rubbing test described above. The results are shown in Table IV.

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Latexes are applied as adjacent test specimens to the same piece of standard redwood cladding. The test plate is then successively air-dried for 65 hours, immersed in a bath of deionized water, and examined for the behavior of the coatings. For comparison with the cationic latexes of this invention, a highly stable anionic latex containing a copolymer of styrene, butadiene, hydroxyethyl acrylate and itaconic acid is used for coating and tested in the same manner (Comparative Example C-8).

The anionic latex (C-8) begins to be absorbed into the wood immediately after application (poor spreadability). Cationic latexes IV-XI remain on the surface and do not show a tendency for absorption (excellent spreadability). After drying, the anionic latex produces a coating with a matte appearance. Cationic latexes IV-XI provide clear, glossy coatings that adhere strongly to the surface of redwood. The test results are summarized in Table V.

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It can be seen that, with the exception of latex IX, all cationic latices tested have excellent water resistance after drying compared to the stable anionic latex of the styrene / butadiene copolymer group.

Examples XII-XIX

A precursor latex is prepared in a batch emulsion polymerization reactor using 2% azobis-isobutyronitrile as initiator, 1% dodecylbenzyldimethylsulfonium chloride as surfactant and 0.1 part dodecanethiol and 0.1 part 2,6-di-t-butyl-1-ketun-1-kreso part towards monomers. The initiator, surfactant, chain transfer agents and 233 parts of water are charged to the reactor. Two parts of 2-hydroxyethyl acrylate and 1.33 parts of styrene are added and the reactor is purged with nitrogen. Sufficient additional styrene is added to give a total of 30 parts and 63 parts of butadiene are added, the temperature is raised to 50 ° C and maintained there for H hours, then it is raised to 70 ° C and maintained there until the rate of pressure drop equalizes, i. about 7 hours. 5 parts of vinylbenzyl chloride are then added and the temperature is maintained at 70 ° C for a further two hours. The contents of the reactor are stirred throughout the reaction cycle. After the reactor is opened to the outside air and the reaction mixture is cooled, the product is found to be a liquid latex (C-9) with a dry matter content of 27.7%, particle size 125 nm. and pH 3.7. Latex is unstable to flame forces (less than 1 abrasion).

The various nucleophiles shown in Table VI are mixed with separate portions of latex C-9 and allowed to react at the temperature and time indicated in the table. The reaction time is chosen approximately according to the amount of time required to obtain the products which are highly abrasion stable, i. stable for more than 20 abrasions. For Example XII and Example XVII, the reaction is carried out at a temperature ranging from 2 to 50 ° C. The latexes obtained after the reaction are stripped in vacuo and filtered.

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26 62108

The pH of the filtered products is adjusted to the desired range to provide mixtures used to coat aluminum test plates (Parker 3003 - H 14, 4 in x 6 in x 0.025 in (10.16 cm x 15.24 cm x 0.06 cm). These mixtures are shown in Table VII .

Table VII

Example No. Dry matter% EH

XII 41.3 8.9 XIII 41.4 8.5 XIV 31.5 7.4 XV 43.2 9.0 XVI 38.1 9.0 XVII 38.9 8.4 XVIII 40.1 11.9 XIX 39.6 11.9

Two coated plates for each example are dried in an oven at 175 ° C, one plate for 5 minutes and the other for 30 minutes. The dried plates are then immersed in water at 70 ° C for two hours and the appearance is recorded before and after the water treatment. The results are shown in Table VIII.

27,621 08

Table VIII

Example Water soaking3 ^ _Curing conditions ^ ___ N: 0 Drying for 5 minutes 30 min. drying appearance appearance. I. ♦ "----- _______- XII Before Dark Yellow Dark Yellow After Blurred No Effect XIII Before Bright Clear After Bright Clear XIV Before Slightly Yellow Dark Yellow After Bright Dark Yellow XV Before Bright Bright After Bright Bright XVI Before Bright Bright After Bright Clear XVII Before Yellow Slightly yellow After Faded Unchanged XVIII Before Yellow Dark Yellow After Faded Unchanged XIX Before Yellow Dark Yellow After Faded Unchanged a = 'Plate immersed in a 70 ° C water bath for 2 hours at b = 175 ° C.

In addition, it is found that the adhesion of the coatings is good on all dried sheets in Examples XII-XIX before the hot water treatment as determined by applying a piece of pressure-sensitive tape (Scotch tape) and then rapidly pulling the tape off. After the water treatment, the adhesion is tested in the same way after excess water has been blown off the plates and dried in air at room temperature for 30 minutes. In this experiment, no coating came off any plate.

Examples XX-XXII

A latex is prepared as a batch preparation by emulsion polymerization by reacting 40 parts of styrene and 55 parts of butyl acrylate in 300 parts of water using 0.2 dodecanethiol, 2 parts of azobisisobutyronitrile and 5 parts of dodecylbenzyldimethylsulfonium chloride with stirring for 17 hours at 50 ° C and one hour at 50 ° C. To achieve 90% monomer conversion, then 5 parts of 2-bromoethyl methacrylate are added and the same reaction conditions are maintained for another 2 hours. When the reactor is opened to the outside air and cooled, the product 28 621 08 is found to be a liquid latex (C-10) with a dry matter content of 25.7% and a particle size of 107 nm. Latex has poor shear stress stability (less than 1 abrasion).

The nucleophiles shown in Table IX are mixed with various parts of latex C-10 and the resulting mixtures are allowed to stand at 25 ° C until the reactions have proceeded at least until the latex products are abrasion stable.

Table IX

Nucleophile,

Example Species Time Time ReservationD

days Total Bound XX dimethyl sulfide 0.52 17 0.16 0.06 XXI trimethylamine 0.52 10 0.22 0.10 XXII tetramethylthiourea 0.29 4 0.27 0.15 a. milliequivalents / g calculated on the polymer in the starting latex b milliequivalents / g based on the polymer in the starting latex

Example XXIII

126 g of latex XX, containing 31.1% of dry matter and containing a total of 0.16 milliequivalents of sulphonium groups per gram of polymer, of which 0.06 milliequivalents are chemically bound to or near the surface of the particles, are mixed with an excess of 7: 1 hydrogen peroxide ( 4.97 g of a 30% solution) and the resulting mixture is stirred in a closed reactor at 35 ° C for 22 hours. A significant proportion of sulfonium groups are oxidized to eulfoxonium groups. There is no loss of colloidal stability and the product has significantly less odor than latex XX.

Examples XXIV-XXVI

A latex is prepared by emulsion polymerization by reacting 40 parts of styrene and 55 parts of butyl acrylate in 300 parts of water using 0.2 parts of dodecanethiol, 2 parts of azobisisobutyronitrile and 4 parts of dodecylbenzyldimethylsulfonium chloride with stirring for 18 hours at 50 ° C and 2 hours at 90 ° C. to achieve monomer conversion, after which 5 parts of 2-chloromethylbutadiene are added and the same reaction conditions are maintained for a further 2 hours.

29 62108

When the reactor is opened to the outside air and cooled, the product is found to be a liquid latex (C-11) with a dry matter content of 24.3% and a particle size of 145 .mu.m. Latex has poor shear stability, i.e. less than 1 rub.

The nucleophiles shown in Table X are mixed with different parts of latex C-11 and the resulting mixtures are allowed to stand at 35 ° C at least until the reactions have progressed sufficiently to make the products very abrasion stable (more than 20 abrasions).

Table IX

Nucleophile · Reaction- K

Example time Charge_No_ Species number of days total bound XXIV Thiophane 0.80 4 0.402 0.265 XXV Trimethylamine 0.50 4 0.342 0.205 XXVI Tetramethyl-0.50 4 0.535 0.398 thiourea a milliequiv./g calculated from polymer b in the starting latex b milliequiv. / g based on the polymer in the product latex

Example XXVII

A latex is prepared by emulsion polymerization by reacting 50 parts of methyl methacrylate and 45 parts of butyl acrylate in 300 parts of water using 0.2 parts of dodecanethiol, 2 parts of azobisisobutyronitrile and 4 parts of dodecylbenzyldimethylsulfonium chloride with stirring for 16 hours at 50 ° C and 3 hours at 70 ° C. To achieve a% monomer conversion, then 5 parts of vinyl bromide are added and the same reaction conditions are maintained for another 2 hours.

When the reactor is opened to the outside air and cooled, the product is found to be a liquid latex (C-12) with a dry matter content of 23.8% and a particle size of 149. Latex has poor shear stability (less than 1 abrasion).

A portion of latex C-12 is mixed with 0.52 milliequivalents of tetramethylthiourea for each gram of polymer in the latex portion and the resulting mixture is allowed to stand at 25 ° C for 7 days. The latex product is stable to shear stress (more than 20 abrasions) and has a total charge of 0.28 milliequivalents and a bound charge of 0.20 milliequivalents per gram of polymer in the latex.

Examples XXVIII-XXIX

A latex is prepared by batch emulsion polymerization with 54 parts of styrene, 44 parts of butadiene and 2 parts of 2-hydroxyethyl acrylate using 0.1 part of dodecanethiol as a chain transfer agent, 2,2'-azobis-isobutyronitrile as a catalyst, 1 part of (active) dodecylbenzyl sulfonyl and 7 hours at 70 ° C. After the starting latex (C-13) with a dry matter content of 37.9% has been cooled and filtered through a cheese cloth, it is allowed to stand for 18 hours. As determined by microscopic examination, the latex particles are relatively uniform in size and have an average particle diameter of 126.5 nm. A sufficient amount of deionized water is mixed with 1980 parts (wet weight) of the starting latex to obtain 4000 parts by weight of diluted latex. Diluted latex C-13 and 10 parts of 2,2'-azobisisobutyronitrile are placed in a reactor, which is then purged with nitrogen. After heating the contents of the reactor to 50 ° C, a monomer mixture containing 200 parts of styrene and 50 parts of vinylbenzyl chloride is introduced into the reactor by pressure. The temperature of the reactor contents is raised to 70 ° C and maintained for 4 hours while the contents are stirred. After cooling and filtering the product obtained, it is observed that a latex (C-14) containing 21.0% of dry matter has been obtained. As determined by microscopic irrigation, the latex particles are relatively uniform in size and have an average diameter of 144.4 nm. Comparing the photomicrographs of latex C-13 and C-14 reveals no evidence that any new particles were initiated. Latex C-14 contains 0.042 milliequivalents of chloride ion per gram of dry matter (derived from the emulsifier).

A portion of latex C-14 is mixed with two moles of trimethylamine for each mole of polymerized vinylbenzyl chloride in the latex, and the mixture is stirred for 20 hours at ambient temperature. The resulting latex (XXVIII) is abrasion stable and contains 0.085 milliequivalents of chloride ion per gram of dry matter - indicating that 0.043 milliequivalents of trimethylamine per gram of dry matter has reacted (0.085-0.042). Excess trimethylamine is removed by vacuum distillation (Rinco evaporator).

* 31 62108

The second portion of latex C-14 is treated in the same manner as described for latex XXVIII except that the reaction time is 4 days instead of 20 hours. Latex (XXIX) is abrasion stable and is found to contain 0.24 milliequivalents of chloride ion per gram of dry matter - indicating that 0.2 milliequivalents of trimethylamine per gram of dry matter has reacted (0.24-0.0421.

Example XXX,

A latex is prepared essentially as described in Example II except (a) no second monomer solution is added; (b) the first monomer solution consists of 26% styrene, 24% vinylbenzyl chloride and 4% butadiene as monomers and 0.1 part dodecanethiol per 100 parts monomer; and (c) a continuous initiator stream, a continuous reducing agent stream, stirring, and a reaction temperature of 50 ° C are continued for four hours after the first monomer solution feed is stopped. The product is a liquid latex with 39.8% polymer dry matter. The latex is filtered and dialyzed against deionized water for 72 hours. The amount of emulsifier is adjusted to 0.01 milliequivalents of dodecylbenzyldimethylsulfonium chloride per gram of dry matter. The latex is diluted to a dry matter content of 20% (latex C-15). To the latex C-15 is added 0.25 mil flivalents of dimethyl sulfide per gram of polymer dry matter and the resulting mixture is stirred at 30 ° C. Samples are taken periodically and unreacted vinylbenzyl chloride is stripped from the samples to stop the reaction. the determination. The results are shown in Table XI.

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Table XI

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Reaction time Sulphone union a,., Milli- Particle size Note ia days equiv./g, polymer ^ _ Total_Bound ____ —--- 0 0 10 0.00 - not abrasion stable * .. .a). .

1 0.20 0.10 1190 very stable 'low viscosity 2 0.29 0.19 1190 very stable, low viscosity 4 0.42 0.32 1190 very stable, low viscosity g 0 74 0.64 1390 very stable, thickened 18 1.12 1.02 1450 very stable, thickened 'a)

Stability according to the stability test performed with a Rotovisco viscometer as described above.

These results indicate that the particles swell substantially when the bound charge is 0.64 milliequivalents per gram of polymer or more. High-charge latices cannot be concentrated to a dry matter content of more than 35% without becoming very thick and, in many cases, ungelled. Latexes with 0.1 to 0.32 milliequivalents of bound charge per gram are very stable and have a low viscosity. They contain considerable amounts (1.25-1.47 milliequ./g) of unconverted benzyl chloride groups. When latexes are cast and dried, they form hydrophobic films that can be crosslinked by oxidative vulcanization via butadiene double bonds. The chloromethyl groups in the resulting crosslinked films are then available for quaternization to provide an ionic membrane.

Claims (12)

A process for preparing a latex consisting of cationic particles of a certain structure, wherein at a temperature of 0-80 ° C (A) one of the latex copolymer particles with which activated halogen atoms are chemically bonded is reacted with (B a water-resistant, non-ionic nucleophilic compound capable of diffusing through aqueous media, characterized in that the latex (a) consists of (1) a non-ionic organic polymer core, on which particle surfaces are polymerized a thin layer of a water-insoluble copolymer of an ethylenically unsaturated activated halogen atom containing monomer, or (2) a latex copolymer consisting of (a) an ethylenically unsaturated, nonionic monomer not containing activated halogen atoms, and (b) an ethylenically unsaturated activated halogen atom containing monomer, wherein the total amount of activated halogen atoms in the latex (A) is 0.01-1.4 mil equivalents per gram of polymer and 0.4-2.5 mil equivalents per gram of polymer in a thin layer of pellets. the latex particle surface, and wherein the latex (A) is prepared by emulsion polymerization at 0-80 ° C in the presence of a free radical catalyst and it contains a small stabilizing amount of a cationic surfactant or a mixture of a cationic surfactant and a nonionic surfactant, wherein the amount of surfactant is less than the amount needed to initiate new particles in the presence of additional monomers, and wherein the water-resistant nucleophilic compound (B) is (1) tetra- (C ) thiourea or a compound of the formula (2) R 1 R 2, (3) R 1 R 2 R 3 N, (4) R 1 R 2 R 3 P, (5) R 1 N 2, or (6) P (10 are C 3 -C 4 alkyls and R 1 is H or C 1 -C 4 alkyl, wherein the cation-independent cation groups are chemically bonded at or near the surface of the copolymer particles in a sufficient amount to provide the majority of the colloidal stability of the latex. Process according to Claim 1, characterized in that the reaction is continued until the cationic groups independent of the pH are present in an amount of 0.01-0.5 milliequivalents per gram of copolymer and 0.4-1.6 milliequivalents per gram of polymer in the thin surface layer. 3. A process according to claim 1 or 2, characterized in that the activated halogen atoms are obtained from a copolymerized monomer, which is vinyl benzyl chloride, 2-chloromethyl-butadiene, vinyl bromide, 2-bromomethyl acrylate or methacrylate. 4. A process according to claim 1, characterized in that it comprises a step in which stabilizing amounts of a cationic or nonionic surfactant or a mixture thereof are added after the copolymerization step. 5. A process according to claim 1, characterized in that the temperature is preferably poured between 50-70 ° C during the reaction of the latex copolymer (A) and the nucleophilic compound (B). Aqueous colloid dispersion of a latex consisting of cationic particles of a certain structure, characterized in that it consists of a non-ionic organic polymer core encapsulated with a thin layer of a water-insoluble organic copolymer, in which at the organic copolymer are, on or near the surface of the particles, chemically bound by the pH independent cationic groups in an amount of 0.01-0.5 milliequivalents per gram of latex copolymer or 0.4-2.5 milliequivalents per gram of copolymer in the thin layer. Aqueous colloid dispersion according to claim 6, characterized in that the amount of cationic groups therein is 0.04-0.35 milliequivalents per gram of particles with a certain structure and that the amount of cationic groups therein is below 1.6 milliequivalents per gram of copolymer. the thin layer. Aqueous colloid dispersion according to claim 6 or 7, characterized in that the cationic groups are essentially sulfonium groups, isothiouronium groups or quaternary ammonium groups and that the quaternary ammonium groups are preferably pyridinium groups. Aqueous colloid dispersion according to claim 6, characterized in that the organic polymer core is a copolymer of styrene and butadiene. Aqueous colloid dispersion according to claim 6, characterized in that the organic polymer core is a polymer of acrylic ester or methacrylic ester. 11. Aqueous colloid dispersion according to claim 6, characterized in that the activated halogen atom containing the monomer is vinyl benzyl chloride.