JP2010150420A - Polychloroprene-based latex, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polychloroprene-based latex remarkably reducing an emulsifier in the latex, and having improved stability, water resistance, adhesiveness, adhesion, etc. <P>SOLUTION: The polychloroprene-based latex includes a hydrophilic group-containing water-insoluble polymer comprising a constituent derived from an acrylic monomer, and ≤3 wt.% of a conventional type emulsifier. Furthermore, a method for producing the latex is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polychloroprene latex and a method for producing the same, which can significantly reduce emulsifiers in the latex and have improved stability, water resistance, adhesion, adhesion and the like.

  Adhesives and primers based on polychloroprene (hereinafter may be abbreviated as CR) are applications that make full use of the characteristics of CR such as polarity, cohesive strength, and flexibility. Mainly used in a wide range of fields such as building materials, woodwork, shoemaking, vehicle manufacturing, home crafts. Conventional CR adhesives were mainly used in which CR, tackifier resin, zinc oxide, antioxidant, etc. were dissolved in organic solvents such as toluene, hexane, ethyl acetate, cyclohexane, etc. The demand for solventization is increasing year by year. Although CR latex has been attracting attention as a response to this requirement, conventional CR latex has insufficient adhesiveness and water resistance, and has not yet replaced solvent-based CR adhesives.

  Conventional CR latexes emulsified chloroprene in water using emulsifiers such as rosin acid soap, sodium alkyl sulfate, higher alcohol sodium sulfate ester, polyoxyethylene alkyl ether, alkylamine salt, quaternary ammonium salt, polyvinyl alcohol and the like. Thereafter, the chloroprene is polymerized by adding a radical initiator such as potassium persulfate, and then the unreacted monomer is removed by a method such as steam stripping. The latex contains about 5 wt% of the above-mentioned emulsifier with respect to CR, which is considered to be one of the main factors that hinder the development of adhesiveness and water resistance of the conventional CR latex adhesive. That is, in the process of applying an adhesive based on a conventional CR latex to an adherend and drying, the emulsifier desorbed from the surface of the CR latex particles and the free emulsifier dissolved in water are applied to the surface of the adhesive film or the coated. This is probably because the original adhesiveness of the CR is hindered by orientation at the adherend interface. Therefore, an attempt was made to produce a so-called soapless CR latex that does not contain these emulsifiers. For example, after radical copolymerization of styrene and acrylic acid in water, neutralization with ammonia, followed by addition of chloroprene and emulsion polymerization to obtain a soapless CR latex (Patent Document 1), methyl methacrylate and styrene sulfone A method of radical polymerization of styrene and butadiene using a methyl methacrylate / sodium styrenesulfonate copolymer produced by radical polymerization of sodium acid in water as a seed is disclosed (Patent Document 2).

  However, alkali-soluble polymers or sodium styrenesulfonate copolymers used in place of conventional emulsifiers are basically soluble in water, so there is still room for improvement in water resistance, adhesion, adhesion, etc. was there.

  In addition, polymethyl methacrylate having a carboxyl group at the terminal is synthesized by radical polymerization of methyl methacrylate in the presence of a carboxyl group-containing thiol compound, and a polymethacrylate microemulsion synthesis method using this as an emulsifier ( Patent Document 3) is disclosed.

  However, there is no mention of the properties and applications of soap-free emulsion, the effect of adding a hydrophilic solvent during emulsion polymerization, and the like.

  On the other hand, a method for synthesizing soap-free latex using a chloroprene-based polymer having an acidic group at the terminal has been disclosed (Patent Document 4). Although these can easily prepare soap-free latexes having good water resistance and adhesiveness, there are problems such as the possibility of problems in stability when the pH of the latex is lowered.

  As described above, there is a demand for the development of a latex having further improved stability, adhesion, and water resistance.

JP 58-89602 A JP-A-10-207114 Japanese National Patent Publication No. 10-506428 JP 2008-231226 A

  An object of the present invention is to provide a polychloroprene latex excellent in further stability, adhesion, and water resistance and a method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have solved the conventional problem by emulsion polymerization of chloroprene using a hydrophilic group-containing water-insoluble polymer containing a constituent derived from an acrylic monomer. The present inventors have found that this can be solved and have completed the present invention. That is, the present invention is a polychloroprene latex characterized by containing a hydrophilic group-containing water-insoluble polymer containing a constituent derived from an acrylic monomer, and a conventional emulsifier of 3 wt% or less, and a method for producing the same.

  Hereinafter, the present invention will be described in detail.

  The CR latex of the present invention contains 3 wt% or less conventional emulsifier. The content of the conventional emulsifier of 3 wt% or less does not include the conventional emulsifier used in the conventional emulsion or the content thereof is remarkably reduced. What the content of the conventional emulsifier is remarkably reduced means that the content of the conventional emulsifier exceeds 0 wt% and is 3 wt% or less. When it exceeds 3 wt%, the water resistance, adhesiveness, adhesion and the like of the emulsion are significantly lowered. Examples of the conventional emulsifier include conventionally used anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, and the like. Examples of anionic emulsifiers include higher fatty acid salts and alkenyl succinates. Rosinate, sodium alkyl sulfate, sodium higher alcohol sulfate, alkylbenzene sulfonate, alkyl diphenyl ether disulfonate, sulfonate of higher fatty acid amide, sulfate of higher fatty acid alkylol amide, alkyl sulfobetaine, etc. Nonionic emulsifiers include, for example, polyoxyethylene alkyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene sorbitan fatty acid ester, higher fatty acid alkanolamide, polyvinyl alcohol. Examples of cationic emulsifiers include alkylamine salts, quaternary ammonium salts, and alkyl ether type quaternary ammonium salts. Examples of amphoteric emulsifiers include alkylbetaines, alkylsulfobetaines, alkyls. Examples include amine oxides.

  The CR latex of the present invention contains a hydrophilic group-containing water-insoluble polymer (hereinafter abbreviated as “acrylic hydrophilic group-containing polymer”) containing a constituent derived from an acrylic monomer, instead of the conventional emulsifier. By containing the acrylic hydrophilic group-containing polymer, the dispersion is stabilized with the acrylic hydrophilic group-containing polymer, and the conventional emulsifier is not included or the content thereof can be significantly reduced. The content of the acrylic hydrophilic group-containing polymer in the CR-based latex is not particularly limited. However, in order not to impair the water resistance, adhesive strength, coating strength, etc. of the latex, the polymer contained in the final latex On the other hand, the content of the acrylic hydrophilic group-containing polymer is preferably 15 wt% or less, and more preferably 7 wt% or less.

  The acrylic hydrophilic group-containing polymer in the present invention has sufficient ability to emulsify chloroprene or chloroprene and a monomer copolymerizable with chloroprene in water and to stabilize emulsion particles formed by polymerization of these monomers in water. Is a polymer. In other words, acrylic hydrophilic group-containing polymers form micelles by introducing acidic groups such as sulfonic acid groups, carboxyl groups, phosphoric acid groups, and salts thereof into water-insoluble polymer skeletons mainly composed of acrylic monomers. Thus, it is a water-insoluble polymer that can emulsify the monomer.

  Examples of the hydrophilic group of the acrylic hydrophilic group-containing polymer include a sulfonic acid group, a carboxyl group, a phosphoric acid group, an amino group, a sulfuric acid group, a carboxylate, a sulfonate, a phosphate, an amine salt, and a polyalkylene oxide. There is at least one selected.

  Moreover, as a hydrophilic group which an acryl-type hydrophilic group containing polymer contains, it is preferable from the point of moderate hydrophilicity provision and an emulsification characteristic to have a terminal acidic functional group represented by following General formula (1).

(Polymer) -S-R-X (1)
(In the formula, X represents an acidic functional group or salt, and R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.)
The acrylic hydrophilic group-containing polymer is an acrylic random copolymer, an acidic functional group-containing thiol compound represented by the following general formula (2), or an acidic functional group-containing disulfide compound represented by the following general formula (3) Or a radical polymerizable monomer containing an acrylic monomer in the presence of an acidic functional group-containing thiol compound represented by the following general formula (2) and an acidic functional group-containing disulfide compound represented by the following general formula (3) As the acidic group, a carboxyl group is preferable in terms of solubility in a polymerization solvent, cost, and availability.

HSRX (2)
(In the formula, X represents a carboxyl group or a salt thereof, and R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.)
X-R-S-S-R-X (3)
(In the formula, X represents a carboxyl group or a salt thereof, and R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.)
Examples of the acidic functional group-containing thiol compound include thioglycolic acid, thiomalic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiosalicylic acid, 3-mercaptobenzoic acid, 4-mercaptobenzoic acid, thiomalonic acid, and dithiosuccinic acid. Thiomaleic acid, thiomaleic anhydride, dithiomaleic acid, thioglutaric acid, cysteine, homocysteine, 5-mercaptotetrazole acetic acid, 3-mercapto-1-propanesulfonic acid and the like, and as the acidic functional group-containing disulfide compound, For example, 2,2′-dithiodipropionic acid, 3,3′-dithiodipropionic acid, 4,4′-dithiodibutanoic acid, 2,2′-dithiobisbenzoic acid, 6,6′-dithiodinicotinic acid, etc. Can be mentioned. That is, one of the features of the present invention is that it does not require a copolymerization step with a hydrophobic monomer and an acidic functional group-containing monomer as a base of the polymer constituting the emulsion.

  The main component of the acrylic hydrophilic group-containing polymer used in place of the conventional emulsifier is a constituent derived from an acrylic monomer used in the production of the polymer. Examples of the acrylic monomer include an alkyl ester of (meth) acrylic acid and an alicyclic hydrocarbon ester of (meth) acrylic acid. Examples of the alkyl group site include a methyl group, an ethyl group, a propyl group, Isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, isononyl Decyl group, isodecyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like. The acrylic hydrophilic group-containing polymer may be copolymerized with a radical polymerizable monomer copolymerizable with an acrylic monomer as long as the function as an emulsifier is not impaired. Examples of radical polymerizable monomers copolymerizable with acrylic monomers include styrene monomers, 1,3-butadiene monomers, vinyl ester monomers, acrylamide monomers, methacrylamide monomers, maleate monomers, Examples thereof include vinyl, acrylonitrile, and ethylene. The proportion of the constituent component derived from the acrylic monomer in the constituent component derived from all monomers in the acrylic hydrophilic group-containing polymer is not particularly limited, but in order to maintain the emulsifying ability, the emulsion stability, and the adhesive properties, It is preferable that it is 50-100 wt%.

  Acidic groups in acrylic hydrophilic group-containing polymers are water-insoluble in random copolymers, but emulsify radically polymerizable monomers such as chloroprene monomers in water, and emulsion particles produced by polymerizing these monomers in water. When the thiol compound or disulfide compound is used, it is present at one or two at the end of the polymer.

  The number average molecular weight measured by gel permeation chromatography (GPC) of the acrylic hydrophilic group-containing polymer is not particularly limited, but is preferably 500 to 30000 in order to maintain micelle formation and prevent an increase in emulsion viscosity.

  The production method of the acrylic hydrophilic group-containing polymer is based on a conventional traditional radical polymerization method. That is, in a suitable solvent or in the absence of a solvent, in the presence of a radical initiator such as a peroxide or an azo compound, or a molecular weight regulator (chain transfer agent) such as a thiol compound or a disulfide compound, a radical polymerizable monomer (at least acrylic). System monomers (for example, methacrylic acid ester monomers, acrylic acid ester monomers, etc.) are subjected to radical polymerization (including random copolymerization). At this time, if an acidic functional group-containing thiol compound or an acidic functional group-containing disulfide compound is used, an acrylic hydrophilic group-containing polymer is produced by chain transfer reaction of the growing radicals thereto. The method of synthesizing terminal functional (including acidic groups) polymers using chain transfer reactions to the above compounds is that growth radicals and initiator radicals are chain transferred to functional group-containing thiol compounds and functional group-containing disulfide compounds. As a result of the polymerization of the monomer being restarted by the functional group-containing sulfur radical generated by this, a functional group derived from a thiol compound is introduced into the polymer terminal. This method is described in Advanced Polymer Materials Series 1 High Performance Liquid Polymer Material (Maruzen Co., Ltd., 1990, pages 13 and 32).

  As radical initiators, benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, paramentane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, dicumyl Peroxides, cyclohexane peroxide, succinic peroxide, potassium persulfate, ammonium persulfate, peroxide compounds such as hydrogen peroxide, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2, 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionitrile), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (Cyclohexane-1-carbonite ), 1-[(1-cyano-1-methylethyl) azo] formamide, dimethyl 2,2′-azobis (2-methylpropionate), 4,4′-azobis (4-cyanovaleric acid) 2,2′-azobis (2,4,4-trimethylpentane), 2,2′-azobis {2-methyl-N- [1,1′-bis (hydroxymethyl) -2-hydroxyethyl] propionamide }, 2,2′-azobis {2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis {2- (2-imidazolin-2-yl) propane] disulfate dihydride 2,2′-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl) propane]} dihydrochloride, 2,2′-azobis (1-imino-1-pi Loridino-2-methylpropane) dihydrochloride, 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] An azo compound such as tetrahydrate can be used, but 4,4′-azobis (4-cyanovaleric) for the purpose of increasing the terminal functionality (introduction rate of acidic functional group) of the acrylic hydrophilic group-containing polymer. Acid) and acidic group-containing initiators such as succinic acid peroxide are preferred.

  Solvents for the synthesis of acrylic hydrophilic group-containing polymers include ethers such as tetrahydrofuran, dioxane and dimethoxyethane, ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetone, aromatics such as toluene, benzene and chlorobenzene, dichloromethane 1,1,2-trichloroethane, halogenated hydrocarbons such as dichloroethane, alcohols such as isopropanol, ethanol, methanol, methoxyethanol, ethyl acetate or water can be selected according to the solubility of the thiol compound and disulfide compound . If these compounds are dissolved in a radically polymerizable monomer including an acrylic monomer, no solvent may be used. However, in order to use the acrylic hydrophilic group-containing polymer continuously in the emulsion polymerization process without isolating it from the polymerization system, at least tetrahydrofuran, acetone, methyl ethyl ketone, methyl isobutyl ketone, methoxyethanol, isopropanol, methanol, ethanol, etc. It is preferable to use a hydrophilic solvent.

  The CR latex of the present invention is characterized in that an acrylic hydrophilic group-containing polymer is used in producing chloroprene by emulsion polymerization of chloroprene or a monomer copolymerizable with chloroprene and chloroprene. As described above, a feature of the present invention is that a polychloroprene-based latex can be obtained in which the amount of the conventional emulsifier is greatly reduced or not contained at all by using an acrylic hydrophilic group-containing polymer as an emulsifier. Thereby, water resistance and adhesive properties are improved, and high latex stability in a low pH region can be expected. In addition, what is important here is that it has been found that micelle formation is promoted in the presence of an appropriate amount of a hydrophilic solvent during emulsion polymerization, and the polymerization rate and emulsion stability are greatly improved. . That is, without an appropriate amount of hydrophilic solvent, formation of fine micelles is insufficient, the polymerization rate is slow, and the amount of scale generated during polymerization increases.

  The amount of the acrylic hydrophilic group-containing polymer used in the emulsion polymerization is not particularly limited as long as the monomer can be sufficiently emulsified and sufficient stability of the produced latex can be maintained, but the viscosity increase of the emulsion and the average of the produced emulsion polymer Considering the molecular weight, it is preferably 30 wt% or less of the total charged monomers, and more preferably 20 wt% or less considering the adhesive strength and water resistance of the polymer emulsion.

  The method for emulsion polymerization of chloroprene or chloroprene and a monomer copolymerizable therewith in the production of the CR-based latex of the present invention is the same as conventional emulsion polymerization except that an acrylic hydrophilic group-containing polymer and a hydrophilic solvent are used. .

  Examples from the production of the acrylic hydrophilic group-containing polymer to the production of the CR latex using the acrylic hydrophilic group-containing polymer will be described below.

  First, in a solvent such as tetrahydrofuran, dioxane, dimethoxyethane, methyl ethyl ketone, methyl isobutyl ketone, acetone, toluene, benzene, chlorobenzene, dichloromethane, 1,1,2-trichloroethane, dichloroethane, isopropanol, ethanol, methanol, methoxyethanol, water or An acrylic hydrophilic group-containing polymer solution is synthesized by radical polymerization of a radical polymerizable monomer containing an acrylic monomer in the presence of the acidic functional group-containing thiol compound and acidic functional group-containing disulfide compound in the absence of a solvent. To this polymer solution, triethylamine, diethylamine, triethanolamine, diethanolamine, ethanolamine, propanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, morpholine, N-methylmorpholine, piperazine, 2-amino- Basicity such as 2-methyl-1-propanol, 2-dimethylamino-2-methyl-1-propanol, N-methyldiethanolamine, N-ethyldiethanolamine, monoisopanolamine, ammonia, sodium hydroxide, potassium hydroxide Add water to compound neutralized and stir to form micelles (or add neutral compound with basic compound and add to water under stirring to form micelles Chloroprene and if necessary) Roropuren copolymerizable with monomers, further to prepare a monomer emulsion by adding a molecular weight modifier if necessary. Emulsion polymerization is performed by adding a radical initiator and, if necessary, a reducing agent to the monomer emulsion. In order to maintain the stability of chloroprene by suppressing the formation of 1,2- and 3,4-bonds in chloroprene, the polymerization temperature is preferably 70 ° C. or lower. In order to further ensure the stability of chloroprene, 60 ° C. or lower is preferable. When the target monomer conversion is reached, a polymerization inhibitor is added to stop the polymerization. Then, chloroprene latex is obtained by depressurizingly distilling an unreacted monomer and a hydrophilic solvent. Further, during or after the polymerization, general emulsifiers and dispersants may be added for the purpose of improving the stability of the emulsion, reducing the viscosity, and reducing the surface tension. However, the addition amount of these emulsifiers and dispersants is 3 wt% or less with respect to the chloroprene latex. If it exceeds 3 wt%, the adhesion, adhesion, and water resistance of the chloroprene latex will be remarkable. The emulsifier and dispersant contained in the emulsion are more preferably 1 wt% or less in order to suppress adhesion inhibition, adhesion, and water resistance deterioration due to the emulsifier and dispersant.

  As the hydrophilic solvent, for example, acetone, methyl ethyl ketone, tetrahydrofuran, isopropanol, methoxyethanol, ethanol, methanol, dioxane, dimethoxyethane, methyl isobutyl ketone, butyl cellosolve, ethyl cellosolve, ethyl acetate, etc. can be used. Acetone, methyl ethyl ketone, tetrahydrofuran, isopropanol, methoxyethanol, ethanol, and methanol are preferred because they are low and can be easily removed from the latex after emulsion polymerization. One type of these hydrophilic solvents may be used, or two or more types may be used. The amount of the hydrophilic solvent used is not particularly limited. However, in order to prevent aggregation of emulsion particles while maintaining the effect of promoting micelle formation, the total amount of monomers such as acrylic hydrophilic group-containing polymer and chloroprene is used. It is preferably 5 to 50 wt%, and more preferably 5 to 20 wt%.

  Examples of basic compounds include alkylamines, alkanolamines, ammonia, heterocyclic amines, potassium hydroxide, sodium hydroxide, and the like, but the micelle formation, adhesion of chloroprene latex, adhesion, and water resistance are improved. In consideration, alkylamine, alkanolamine, and ammonia are particularly preferable.

  Examples of the molecular weight regulator include mercaptans such as n-dodecyl mercaptan, octyl mercaptan, t-butyl mercaptan, thioglycolic acid, thiomalic acid, and thiosalicylic acid, and sulfides such as diisopropylxanthogen disulfide, diethylxanthogen disulfide, and diethylthiuram disulfide. , Halogenated hydrocarbons such as iodoform, diphenylethylene, p-chlorodiphenylethylene, p-cyanodiphenylethylene, α-methylstyrene dimer, sulfur and the like can be used.

  Examples of radical initiators include peroxide compounds such as benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, paramentane hydroperoxide, dicumyl peroxide, potassium persulfate, ammonium persulfate, and 2,2 ′. -Azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionitrile), 2,2 '-Azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl) azo] formamide, dimethyl 2,2'- Azobis (2-methylpropionate), 4,4′-azobis (4-cyanovale Acid), 2,2′-azobis (2,4,4-trimethylpentane), 2,2′-azobis {2-methyl-N- [1,1′-bis (hydroxymethyl) -2-hydroxyethyl] Propionamide}, 2,2′-azobis {2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis {2- (2-imidazolin-2-yl) propane] disulfate Dihydrate, 2,2′-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl) propane]} dihydrochloride, 2,2′-azobis (1-imino-1) -Pyrrolidino-2-methylpropane) dihydrochloride, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis N-(2-carboxyethyl) -2-methylpropionamidine] azo compound of tetra-hydrate and the like can be used.

  As the reducing agent for promoting the decomposition of the peroxide, for example, hydrosulfite, Rongalite, sodium sulfite, sodium thiosulfate, ferrous sulfate, ascorbic acid, aniline and the like can be used. Examples of the polymerization inhibitor include phenothiazine, 2,6-di-tert-butyl-4-methylphenol, 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), tris (nonylphenyl) phosphite, 4,4′-thiobis (3-methyl-6-tert-butylphenol), N-phenyl-1-naphthylamine, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2-mercaptobenzimidazole, Hydroquinone, N, N-diethylhydroxylamine and the like can be used.

  CR-based latex of the present invention includes rosin acid ester resin, terpene phenol resin, petroleum resin, coumarone indene resin and other tackifying resins, alkylphenol resin, salt of acidic functional group-containing resin, silica, clay, aluminum paste, titanium oxide , Inorganic fillers such as zeolite, calcium carbonate, carbon, hydrophobized cellulose, polycarboxylates, associative nonionic surfactants, polyalkylene oxides, thickeners such as clay, polyisocyanate compounds, epoxy resins, oxazoline compounds, Curing agents such as carbodiimide compounds, hydrazine derivatives, silane compounds, acid acceptors such as zinc oxide, hydrotalcide, epoxy resins, pH adjusters such as sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, phosphoric acid, Plasticizer, wetting agent, freezing Inhibitor, by blending Zomakusuke agent, adhesives may be used primers, sealants, binders, as coatings.

  The CR latex obtained in the present invention is a CR latex adhesive, primer, and coating agent with significantly improved adhesion and water resistance since the amount of emulsifier contained in the conventional polychloroprene latex is significantly reduced. In addition to sealants, it is possible to manufacture binders such as gloves, thread rubber, etc., rubberized fabrics such as balloons, rubber boats, textile processing, capacitors and secondary battery electrode binders, inks, toners, magnetic paints, etc. To.

  In order to describe the present invention more specifically, examples are shown below, but the present invention is not limited to these examples.

  The number average molecular weight Mn, the weight average molecular weight Mw and the molecular weight distribution Mw / Mn of the polymer of the present invention were measured under the following conditions by GPC8220 manufactured by Tosoh Corporation (eluent = tetrahydrofuran, flow rate = 1.0 ml / m). min, column temperature = 40 ° C., peak detection = differential refractometer, packed column = TSK-gel (registered trademark, the same applies hereinafter) G7000Hxl / GMHxl / GMHxl / G3000Hxl / guard column HL, molecular weight calculation = polystyrene conversion). The monomer conversion during polymerization was calculated using Shimadzu Gas Chromatograph GC-17A (GL Sciences capillary column NEUTRABOND-5, flame ionization detector) using benzene as a standard substance.

  The particle size of the CR latex was measured with Microtrac UPA (Nikkiso Co., Ltd.) after diluting the CR latex with distilled water to 0.01 to 0.1 wt%.

  The mechanical stability of the CR-based latex was measured by weighing 100.0 g after filtering the latex, which had been allowed to stand in a temperature-controlled room (23 ° C.) for 30 minutes or more, through a 100-mesh stainless steel wire mesh, The rubber precipitation rate of the latex was measured by the Marlon test method with reference to the former JISK6392.

  The performance (adhesion performance) of the CR latex as an adhesive was evaluated by the following method. Applying CR-type latex (0.3 parts by weight of Nissin Chemical Industry's wetting agent (Olfin EXP.4036) to 100 parts by weight of CR-type latex) with two brushes on No. 9 cotton canvas Then, after drying in an oven at 70 ° C. for 3 minutes (the above coating-drying operation was repeated three times), an open time (leaving for a fixed time) was taken at room temperature, and then pressure bonding was performed with a hand roller. After curing at room temperature for 3 days, it was cut to a width of 25 mm, and a 180 ° T-type peel test was performed using a Tensilon-type tensile tester under the condition of a tensile speed of 100 mm / min. Adhesiveness was evaluated from changes in peel strength and peel state due to open time. That is, when the adhesiveness is sufficient, the decrease in peel strength is small even when a long open time is taken, but when it is insufficient, the peeling (so-called glue separation) at the adhesive interface becomes remarkable and the peel strength decreases. Increase. The water resistance is evaluated by performing a 180 ° T-type peel test in the same manner as described above after a test piece cured at room temperature for 3 days after crimping at an open time of 1 hour, immersed in pure water for 3 days at room temperature, and then wet. did.

  Evaluation of the long-term stability of the CR latex was determined by the presence or absence of rubber precipitation when the unblended CR latex was allowed to stand in a 50 ° C. atmosphere for 30 days.

Example 1
A 500 ml brown glass flask equipped with a three-way cock was charged with 10.0 g of thioglycolic acid, 1.7 g of 4,4′-azobis (4-cyanovaleric acid), and 120.0 g of acetone, and then dissolved in ethyl acrylate. Add 100.0 g, thoroughly freeze and degas-thaw twice and then thoroughly deaerate, then heat in a 50 ° C oil bath while stirring with a magnetic stirrer in a nitrogen atmosphere, and contain acrylic hydrophilic groups An acetone solution of the polymer was obtained. The polymerization conversion of ethyl acrylate after 48 hours was 98.5%.

  The number average molecular weight Mn of the produced polymer measured by GPC was 1800, and the weight average molecular weight Mw was 3000.

  Subsequently, in a 500 ml glass flask equipped with a three-way cock, 20.0 g of an acetone solution of the acrylic hydrophilic group-containing polymer synthesized above, 1.4 g of triethylamine (1.2 equivalents of carboxyl groups contained in the solution), 2. 0.4 g of n-dodecyl mercaptan and 150.0 g of pure water were added and mixed, then 178.0 g of chloroprene was added, and nitrogen was passed for 30 minutes at a flow rate of 1 L / min, followed by sufficient deaeration. Polymerization was performed by adding 0.5 ml of a 4 wt% potassium persulfate aqueous solution and stirring with a magnetic stirrer at room temperature. Polymerization was stopped by adding 0.2 g of phenothiazine after 5 hours of polymerization while adding 0.5 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 91.5%, and no generation of scale was observed. Unreacted monomers, acetone and water were distilled off with a rotary evaporator to obtain CR latex-A (solid content 50.0 wt%).

  The CR-latex-A had a Marlon test precipitation rate of 0.014 wt% and an average particle size of 118 nm, and was a very stable latex (the amount of carboxyl groups relative to the polymer in the latex was about 0.4 wt%).

  Table 1 shows the content of the hydrophilic group-containing water-insoluble polymer in the CR latex A, the content of the constituent components derived from the acrylic monomer, the type of the hydrophilic group, and the number average molecular weight.

実施例２
三方コックを備えた５００ｍｌ褐色ガラスフラスコに、チオリンゴ酸１８.０ｇ、２，２‘−アゾビス（２，４−ジメチルバレロニトリル）１．７ｇ、及びアセトン１２０．０ｇを仕込んで溶解後、メタクリル酸メチル１２０．０ｇを添加し、凍結―脱気―融解を２回繰り返して十分脱気した後、窒素雰囲気下、マグネチックスターラーで攪拌しながら、５０℃のオイルバスで加熱し、アクリル系親水基含有ポリマーのアセトン溶液を得た。４６時間後のメタクリル酸メチルの重合転化率は９９．９％だった。

Example 2
A 500 ml brown glass flask equipped with a three-way cock was charged with 18.0 g of thiomalic acid, 1.7 g of 2,2′-azobis (2,4-dimethylvaleronitrile), and 120.0 g of acetone, and then dissolved in methyl methacrylate. Add 120.0 g, thoroughly freeze and degas-thaw twice, then heat in a 50 ° C oil bath while stirring with a magnetic stirrer in a nitrogen atmosphere to contain acrylic hydrophilic groups An acetone solution of the polymer was obtained. The polymerization conversion of methyl methacrylate after 46 hours was 99.9%.

  The number average molecular weight Mn of the produced polymer measured by GPC was 1290, and the weight average molecular weight Mw was 2300.

  Subsequently, in a 500 ml glass flask equipped with a three-way cock, 20.0 g of an acetone solution of the acrylic hydrophilic group-containing polymer synthesized above, 2.2 g of triethylamine (1.2 equivalents of carboxyl groups contained in the solution), 2. 0.4 g of n-dodecyl mercaptan and 160.0 g of pure water were added and mixed, then 190.0 g of chloroprene was added, and nitrogen was passed for 30 minutes at a flow rate of 1 L / min, followed by sufficient deaeration. Polymerization was performed by adding 0.5 ml of a 4 wt% potassium persulfate aqueous solution and stirring with a magnetic stirrer at room temperature. Polymerization was stopped by adding 0.2 g of phenothiazine after 6 hours of polymerization while adding 0.5 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 91%, and no generation of scale was observed. Unreacted monomers, acetone and water were distilled off with a rotary evaporator to obtain CR latex-B (solid content 52.0 wt%).

  The CR-latex-B had a Marlon test deposition rate of 0.010 wt% and an average particle size of 109 nm, and was a very stable latex (the amount of carboxyl groups relative to the polymer in the latex was about 0.4 wt%).

  Table 1 shows the content of the hydrophilic group-containing water-insoluble polymer in the CR-based latex-B, the content of the components derived from the acrylic monomer, the type of the hydrophilic group, and the number average molecular weight.

Example 3
A 500 ml brown glass flask equipped with a three-way cock was charged with 18.0 g of thiomalic acid, 1.7 g of 2,2′-azobis (2,4-dimethylvaleronitrile), and 120.0 g of tetrahydrofuran, and then dissolved in methyl methacrylate. After adding 96.0 g and 24.0 g of styrene, repeating freezing-degassing-thawing twice and thoroughly degassing, heat in a 50 ° C. oil bath while stirring with a magnetic stirrer under a nitrogen atmosphere, An acetone solution of an acrylic hydrophilic group-containing polymer was obtained. The polymerization conversion of methyl methacrylate / styrene after 40 hours was 90/99%.

  The number average molecular weight Mn of the produced polymer measured by GPC was 1800, and the weight average molecular weight Mw was 31000.

  Subsequently, in a 500 ml glass flask equipped with a three-way cock, 18.0 g of a tetrahydrofuran solution of the acrylic hydrophilic group-containing polymer synthesized above, 0.4 g of n-dodecyl mercaptan, 4.1 g of a 20.4 wt% KOH aqueous solution (the above solution) And 1.22.0 equivalents of the carboxyl group contained in the water) and 152.0 g of pure water were added and mixed, then 180.0 g of chloroprene was added, and nitrogen was passed for 30 minutes at a flow rate of 1 L / min for sufficient degassing Then, 0.5 ml of a 3.4 wt% potassium persulfate aqueous solution was added, and polymerization was carried out by stirring with a magnetic stirrer at room temperature. Polymerization was stopped by adding 0.2 g of phenothiazine after 8 hours of polymerization while adding 0.5 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 90%, and no generation of scale was observed. Unreacted monomers, acetone and water were distilled off with a rotary evaporator to obtain CR-based latex-C (solid content 51.0 wt%).

  The CR-based latex-C had a Marlon test precipitation rate of 0.0121 wt% and an average particle size of 128 nm, and was a very stable latex (the amount of carboxyl groups relative to the polymer in the latex was about 0.4 wt%).

  Table 1 shows the content of the hydrophilic group-containing water-insoluble polymer in the CR-based latex-C, the content of the constituent components derived from the acrylic monomer, the type of the hydrophilic group, and the number average molecular weight.

Example 4
A 500 ml brown glass flask equipped with a three-way cock was charged with 6.4 g of n-dodecyl mercaptan, 1.7 g of 2,2′-azobis (2,4-dimethylvaleronitrile) and 100.0 g of acetone, and 90. 5 g and 10.1 g of methacrylic acid were added, and after freezing, degassing and thawing were repeated twice, the mixture was sufficiently deaerated and then heated in an oil bath at 50 ° C. while stirring with a magnetic stirrer in a nitrogen atmosphere. Acetone solution of a polymer having a hydrophilic group was obtained. The polymerization conversion of methyl methacrylate / methacrylic acid after 24 hours was 93/90%.

  The number average molecular weight Mn of the produced polymer measured by GPC was 2200, and the weight average molecular weight Mw was 4800.

  Subsequently, in a 500-ml glass flask equipped with a three-way cock, 20.3 g of an acetone solution of the acrylic hydrophilic group-containing polymer synthesized above, 0.3 g of n-dodecyl mercaptan, 1.4 g of triethylamine (carboxyl groups contained in the above solution) 1.2 equivalent) and 121.0 g of pure water, and after mixing, 140.0 g of chloroprene was added, and nitrogen was passed at a flow rate of 1 L / min for 30 minutes to sufficiently deaerate. Polymerization was performed by adding 0.5 ml of a 4 wt% potassium persulfate aqueous solution and stirring with a magnetic stirrer at room temperature. Polymerization was stopped by adding 0.2 g of phenothiazine after 5 hours of polymerization while adding 0.5 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 92%, and no generation of scale was observed. Unreacted monomers, acetone and water were distilled off with a rotary evaporator to obtain CR latex-D (solid content 51.0 wt%).

  The CR-latex-D had a Marlon test precipitation rate of 0.0098 wt% and an average particle size of 98 nm, and was a very stable latex (the amount of carboxyl groups relative to the polymer in the latex was about 0.4 wt%).

  Table 1 shows the content of hydrophilic group-containing water-insoluble polymer in CR latex-D, the content of constituents derived from acrylic monomers, the type of hydrophilic groups and the number average molecular weight.

Example 5
In a 500 ml brown glass flask equipped with a three-way cock, 6.4 g of n-dodecyl mercaptan, 1.7 g of 2,2′-azobis (2,4-dimethylvaleronitrile), LiSS (manufactured by Tosoh Organic, lithium styrene sulfonate) 10 1.0 g and 120.0 g of ethanol were added, 80.0 g of methyl methacrylate was added, and after freezing-degassing-thawing was repeated twice and sufficiently degassing, the mixture was stirred with a magnetic stirrer in a nitrogen atmosphere. And heated in an oil bath at 40 ° C. to obtain an acetone solution of an acrylic hydrophilic group-containing polymer. After 48 hours, the polymerization conversion of methyl methacrylate was 97%.

  The number average molecular weight Mn of the produced polymer measured by GPC was 2500, and the weight average molecular weight Mw was 6300.

  Subsequently, in a 500 ml glass flask equipped with a three-way cock, 21.0 g of an ethanol solution of the acrylic hydrophilic group-containing polymer synthesized above, 0.3 g of n-dodecyl mercaptan, 1.0 g of triethylamine (carboxyl groups contained in the above solution) 1.1 equivalent amount) and 116.0 g of pure water were added and mixed, then 140.0 g of chloroprene was added, nitrogen was passed for 30 minutes at a flow rate of 1 L / min, and then sufficiently deaerated. Polymerization was performed by adding 0.5 ml of a 4 wt% potassium persulfate aqueous solution and stirring with a magnetic stirrer at room temperature. Polymerization was stopped by adding 0.2 g of phenothiazine after 6 hours of polymerization while adding 0.5 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 90%, and no generation of scale was observed. Unreacted monomers, ethanol and water were distilled off with a rotary evaporator to obtain CR-based latex-E (solid content 50.0 wt%).

  The CR-based latex-E had a Marlon test precipitation rate of 0.017 wt% and an average particle size of 158 nm, and was a very stable latex (the amount of carboxyl groups relative to the polymer in the latex was about 0.3 wt%).

  Table 1 shows the content of hydrophilic group-containing water-insoluble polymer in CR latex-E, the content of constituents derived from acrylic monomers, the type of hydrophilic groups and the number average molecular weight.

Comparative Example 1
In a 500 ml glass flask equipped with a three-way cock, 7.0 g of Perex SSH (made by Kao, sodium dodecyl diphenyl ether disulfonate) as a conventional emulsifier, 0.5 g of sodium hydroxide, 120.0 g of pure water, n-dodecyl mercaptan, 0. 4 g and 150.0 g of chloroprene were charged to prepare a monomer emulsion. To this, 0.5 ml of an aqueous initiator solution (containing 3.4 wt% potassium persulfate and 0.1 wt% sodium anthraquinone sulfonate) was added. After sufficiently degassing by flowing nitrogen at a flow rate of 1 L / min for 30 minutes, polymerization was carried out at room temperature while stirring with a magnetic stirrer. Polymerization was stopped by adding 50.0 mg of phenothiazine after 8 hours of polymerization while adding 0.5 ml of the above initiator aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 90%, and no generation of scale was observed. Unreacted monomers and water were distilled off using a rotary evaporator to obtain CR latex-F (solid content: 47.0 wt%).

  The CR latex-F had a Marlon test precipitation rate of 0.024 wt% and an average particle size of 148 nm, and was a highly stable latex.

  Table 1 shows the content of the conventional emulsifier, the type of hydrophilic group, and the number average molecular weight in the CR latex-F.

Comparative Example 2
In a 200 ml eggplant-shaped flask, 20.0 g of an acetone solution of the acrylic hydrophilic group-containing polymer polymerized in Example 2, 1.6 g of triethylamine (1.2 equivalents of carboxyl groups contained in the solution), and 130. After adding 0 g and mixing, acetone was removed by distillation under reduced pressure. Thereafter, the contents were transferred to a 200 ml glass flask equipped with a three-way cock, 0.4 g of n-dodecyl mercaptan and 150.0 g of chloroprene were added with stirring, and nitrogen was flowed for 30 minutes at a flow rate of 1 L / min for sufficient desorption. After gassing, 0.5 ml of a 3.4 wt% potassium persulfate aqueous solution was added, and the mixture was stirred and polymerized at room temperature with a magnetic stirrer. The polymerization was terminated by adding 50.0 mg of phenothiazine after 9 hours of polymerization while adding 0.2 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was slightly low as 81.9%, and a massive scale was observed. Unreacted monomer was distilled off with a rotary evaporator to obtain CR-based latex-G (solid content 51.0 wt%).

  The CR-latex-G had a Marlon test precipitation rate of 0.43 wt%, coarse particles having an average particle size of 136 nm and a particle size of several thousand nm, and latex stability was greatly inferior to that of the Examples.

  Table 1 shows the content of the hydrophilic group-containing water-insoluble polymer in the CR latex-G, the content of the components derived from the acrylic monomer, the type of the hydrophilic group, and the number average molecular weight.

Reference Example A 500 ml brown glass flask equipped with a three-way cock was charged with 10.3 g of thiomalic acid, 1.7 g of 4,4′-azobis (4-cyanopentanoic acid) and 89.5 g of acetone and dissolved, and then 120.9 g of chloroprene. Was added, and freeze-deaeration-thawing was repeated twice to sufficiently deaerate, and then the mixture was heated in an oil bath at 50 ° C. while stirring with a magnetic stirrer under a nitrogen atmosphere, and a polymer containing a chloroprene terminal acidic group ( An acetone solution of (CR polymer-thiomalic acid) was obtained. The polymerization conversion of chloroprene after 65 hours was 82.5%.

  The number average molecular weight Mn of the produced polymer measured by GPC was 2700, and the weight average molecular weight Mw was 4200.

  Subsequently, in a 200 ml glass flask equipped with a three-way cock, 7.0 g of an acetone solution of CR (CR polymer-thiomalic acid) containing terminal acidic groups synthesized above, 0.1 g of n-dodecyl mercaptan, 20.4 wt% KOH 0.9 g of aqueous solution, 0.1 g of 16% NaOH aqueous solution (1.2 equivalent of carboxyl group contained in the above solution) and 37.2 g of pure water were added and mixed, and then 39.3 g of chloroprene and 3.4 wt% were added. 0.2 ml of an aqueous potassium persulfate solution was added (addition amount of terminal acidic group-containing CR to the charged monomer was about 16.4 wt%). After sufficiently degassing by flowing nitrogen for 30 minutes at a flow rate of 1 L / min, heating was started in an oil bath at 40 ° C. while stirring with a magnetic stirrer. The polymerization was terminated by adding 50.0 mg of phenothiazine after 9 hours of polymerization while adding 0.2 ml of the above potassium persulfate aqueous solution every 2 hours. The polymerization conversion rate of chloroprene was 90.2%, and no generation of scale was observed. Unreacted monomers, acetone and water were distilled off with a rotary evaporator to obtain CR latex-H (solid content: 48.0 wt%).

  The CR-latex-H had a Marlon test deposition rate of 0.011 wt% and an average particle size of 103 nm, and was a very stable latex (the amount of carboxyl groups relative to the polymer in the latex was about 0.6 wt%).

  Table 1 shows the content of the chloroprene terminal acidic group-containing polymer in CR latex-H, the type of hydrophilic group, and the number average molecular weight.

  Table 2 shows the results of evaluating the adhesion performance and long-term stability using the CR latexes obtained in Examples 1 to 5, Comparative Example 1 and Reference Example. The CR latex-G of Comparative Example 2 was not worthy of an adhesion test because of its poor latex stability.

表２から、実施例１〜５のＣＲ系ラテックスは、比較例１のＣＲ系ラテックスと比較して、オープンタイムによる剥離強度低下及び水浸漬後の剥離強度低下が少なく、従来ラテックスに比べて接着性、耐水性が著しく向上していることが明らかである。

From Table 2, the CR latexes of Examples 1 to 5 are less bonded to the conventional latex than the CR latex of Comparative Example 1 with less decrease in peel strength due to open time and less decrease in peel strength after water immersion. It is clear that the properties and water resistance are remarkably improved.

  Moreover, from Table 2, the CR latexes of Examples 1 to 5 were excellent in long-term stability as compared with the CR latexes of Reference Examples.

Claims (9)

A polychloroprene latex characterized by containing a hydrophilic group-containing water-insoluble polymer containing a constituent derived from an acrylic monomer and a conventional emulsifier of 3 wt% or less. 2. The polychloroprene system according to claim 1, wherein the proportion of the component derived from the acrylic monomer is 50 to 100 wt% with respect to the component derived from all monomers in the hydrophilic group-containing water-insoluble polymer. latex. Hydrophilic groups of hydrophilic group-containing water-insoluble polymers containing components derived from acrylic monomers are sulfonate groups, carboxyl groups, phosphate groups, amino groups, sulfate groups, carboxylates, sulfonates, phosphates, amines The polychloroprene latex according to claim 1 or 2, wherein the latex is at least one selected from a salt and a polyalkylene oxide. 4. The terminal acidic functional group represented by the following general formula (1) is included as a hydrophilic group contained in a hydrophilic group-containing water-insoluble polymer containing a component derived from an acrylic monomer. The polychloroprene latex according to any one of the above.
(Polymer) -S-R-X (1)
(In the formula, X represents an acidic functional group or salt, and R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.) The polychloroprene latex according to any one of claims 1 to 4, wherein the hydrophilic group-containing water-insoluble polymer containing a component derived from an acrylic monomer is an acrylic random copolymer. Hydrophilic group-containing water-insoluble polymer containing a component derived from an acrylic monomer is an acidic functional group-containing thiol compound represented by the following general formula (2), an acidic functional group-containing disulfide compound represented by the following general formula (3) Or a polymer obtained by radical polymerization in the presence of an acidic functional group-containing thiol compound represented by the following general formula (2) and an acidic functional group-containing disulfide compound represented by the following general formula (3). The polychloroprene-based latex according to any one of claims 1 to 5, wherein
HSRX (2)
(In the formula, X represents an acidic functional group or salt, and R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.)
X-R-S-S-R-X (3)
(In the formula, X represents an acidic functional group or salt, and R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.) The number average molecular weight calculated | required by the gel permeation chromatography (GPC) of the hydrophilic group containing water-insoluble polymer containing the structural component derived from an acryl-type monomer is 500-30000, The any one of Claims 1-6 characterized by the above-mentioned. The polychloroprene-based latex described in the item 4. The polypolymer according to any one of claims 1 to 7, wherein the emulsion polymerization is performed using a hydrophilic group-containing water-insoluble polymer containing a component derived from an acrylic monomer in the presence of a hydrophilic solvent. A method for producing chloroprene latex. The method for producing a polychloroprene latex according to claim 8, wherein the hydrophilic solvent is at least one solvent selected from acetone, methyl ethyl ketone, tetrahydrofuran, isopropanol, methoxyethanol, ethanol, and methanol.