WO2016133192A1 - Latex composition and one-pack aqueous adhesive - Google Patents

Abstract

Provided is a latex composition suitable for use in a one-pack adhesive that exhibits excellent normal adhesive strength to adherends such as cloth, leather, and paper. Also provided is a one-pack aqueous adhesive using the latex composition. This latex mixture contains: 100 parts by mass, in terms of solid content, of a chloroprene polymer latex having a pH of at least 12; and 10-50 parts by mass, in total, of at least one aqueous dispersion selected from among terpene phenol resin emulsions, acrylic latexes having a glass transition temperature of -40°C to -10°C, and epoxy resin emulsions having a carboxyl group and a pH of 8.0-11.0. It is preferable that the chloroprene polymer has a gel content of 5-30 mass%, the number-average molecular weight of the toluene-soluble portion is 200,000 to 500,000, and the molecular weight distribution is 2.0-4.0. The latex composition can be suitably used as a one-pack aqueous adhesive for bags and shoes.

Description

Latex composition and one-component aqueous adhesive

The present invention relates to a latex composition containing a chloroprene polymer latex and at least one aqueous dispersion selected from a terpene phenol resin emulsion, an acrylic latex and an epoxy resin emulsion, and a one-component aqueous adhesive using the same. About.

Common adhesives are manufactured using vinyl acetate polymers, chloroprene polymers, acrylate polymers, natural rubber, urethane polymers, and the like as raw materials. Among these, chloroprene polymers are suitably used for adhesive applications such as solvent-based contact adhesives and graft adhesives because a high degree of adhesion can be obtained with a low pressure bonding to a wide range of adherends. However, volatile organic compound (VOC) regulations are necessary when solvent-based bonding is performed due to consideration of environmental pollution and human health, in addition to the risk of ignition in the work environment and the cost of special exhaust and recovery equipment taken to prevent it. And solvent regulations have become stricter year by year.
In order to eliminate the solvent in order to comply with this regulation, water-based adhesives using chloroprene polymer latex are being developed actively. However, water-based adhesives have better adhesive strength than conventional solvent-based adhesives. There is a problem that is low.

Therefore, a two-part adhesive has been studied as a technique for improving the adhesive strength of the adhesive, particularly the initial adhesive strength. For example, as a main agent, a specific polychloroprene latex is added to an acrylic latex or an SBR type. 2. Description of the Related Art Two-component adhesives using a composition in which a specific amount of latex and an anionic surfactant are blended and using a polyvalent metal salt as a curing agent (see Patent Documents 1 and 2) are known.
The two-component adhesive has no problem when applied to an adherend with a brush or a roller. However, when spraying these adhesives, the pot life of the adhesive and the initial adhesive force cannot be balanced, the mixing ratio of the adhesive is not stable, the bonding operation is not stable, and the spray is clogged. There are many troubles such as.

In addition, as a method of bonding the fiber and the rubber, a technique in which nylon fiber is treated with RFL containing chloroprene latex and then heat-treated at 180 ° C. or higher (see Patent Document 3), or polyester fiber is preliminarily epoxy compounded. After the treatment with the above, a technique of treating with a mixture of RFL and 2,6-bis- (2′-4′-dihydroxyphenylmethyl) -4-chlorophenol and heat-treating at 140 to 160 ° C. (see Patent Document 4) It has been known.
However, these adhesion methods immerse the adherend and thus have poor design properties after bonding, and are not suitable for applications that require design properties such as handbags and shoes.

JP 56-59874 A Japanese Patent Laid-Open No. 9-188860 JP 59-211681 A JP 52-117388 A

The present invention relates to a latex composition suitable for use in a one-part adhesive exhibiting excellent normal adhesive strength for an adherend of cloth, leather, and paper, and a one-part aqueous system using the same. It is an object to provide an adhesive.

As a result of intensive studies to solve the above problems, the present inventors have made chloroprene polymer latex contain at least one aqueous dispersion selected from terpene phenol resin emulsion, acrylic latex and epoxy resin emulsion. It has been found that the above problems can be solved by the latex composition.

That is, the present invention relates to (A) 100 parts by mass of a chloroprene polymer latex having a pH of 12 or more, (B) a terpene phenol resin emulsion, and a glass transition temperature (Tg) of −40 to −10 ° C. A latex mixture containing at least one aqueous dispersion selected from an acrylic latex and an epoxy resin emulsion having a carboxyl group with a pH of 8.0 to 11.0 in total in terms of solid content of 10 to 50 parts by mass.
The chloroprene polymer contained in the chloroprene polymer latex has a gel content (toluene insoluble content) of 5 to 30% by mass, a toluene soluble content number average molecular weight of 200,000 to 500,000, and a molecular weight distribution (Mw / Mn) is preferably 2.0 to 4.0. Further, the chloroprene polymer is a chloroprene homopolymer, a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, or a chloroprene homopolymer and chloroprene and 2,3-dichloro-1,3. A mixture with a copolymer with butadiene is preferred. The latex composition can be used as a one-component aqueous adhesive, and can be suitably used as a one-component aqueous adhesive particularly for heels and shoes.

A latex composition suitable for use in a one-part adhesive exhibiting excellent normal adhesive strength, and a one-part aqueous adhesive using the same, can be obtained for adherends of cloth, leather, and paper. It is done.

Hereinafter, the present invention will be described in detail.
The latex composition of the present invention contains (A) a chloroprene polymer latex and (B) a specific aqueous dispersion.

(A) Chloroprene-based polymer latex The chloroprene-based polymer latex is blended in order to improve the contact property, heat-resistant adhesive property, and initial adhesive strength of an adhesive using the latex composition. As the chloroprene polymer latex, the gel content (toluene insoluble content) in the chloroprene polymer constituting the chloroprene polymer latex is 5 to 30% by mass, and the toluene soluble content in the chloroprene polymer is A number average molecular weight of 200,000 to 500,000 and a molecular weight distribution (Mw / Mn) of 2.0 to 4.0 are desirable.

The chloroprene polymer latex can be prepared as an anionic, nonionic, or cationic latex depending on the emulsifier and dispersant used for emulsion polymerization of the chloroprene monomer. When used as a raw material for a one-component aqueous adhesive, it is preferable to use an anionic latex because the initial adhesive strength is increased. Anionic latex is a latex obtained by emulsion polymerization of a monomer using an anionic emulsifier or dispersant.

Examples of the anionic emulsifier and dispersant include alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkyl aryl sulfates, condensates of sodium naphthalene sulfonate and formaldehyde, and sodium alkyl diphenyl ether disulfonates.

Most preferred as anionic emulsifiers and dispersants are rosin acids, such as wood rosin acid, gum rosin acid, tall oil rosin acid, and disproportionated rosin acid obtained by disproportionating these. The rosin acid may be used in the form of an alkali metal salt. The amount of rosin acid added is preferably 0.5 to 10 parts by mass and more preferably 2 to 6 parts by mass with respect to 100 parts by mass of the whole simple substance used. When the amount is less than 0.5 parts by mass, the polymerization solution tends to be poorly emulsified, and problems such as deterioration of polymerization heat generation control, formation of aggregates, and poor product appearance are likely to occur. When the amount is more than 10 parts by mass, the water resistance of the polymer is deteriorated due to the remaining emulsifier, the adhesive strength of the obtained one-component aqueous adhesive is reduced, the foaming at the time of drying and the color tone of the product are deteriorated. Problems are likely to occur.

When rosin acid is used, it is preferable to use a sulfate-based or sulfonate-based anionic emulsifier or dispersant in order to stabilize the chloroprene polymer latex after the addition of the pH adjuster. In this case, the addition amount of an anionic emulsifier and dispersant other than rosin acid is preferably 0.05 to 5.0 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the whole simple substance used. Part.

An anionic emulsifier or dispersant and a nonionic emulsifier or dispersant may be used in combination. By using a nonionic emulsifier in combination, the low-temperature stability of the latex and the adhesive properties when used as an adhesive can be improved. In addition, when a nonionic or cationic emulsifier or dispersant is used alone as an emulsifier or dispersant during emulsion polymerization, sufficient destabilization may occur when a pH regulator is added to form an aqueous adhesive. It does not occur, and there is a possibility that the expression of the initial adhesive force is insufficient.

The chloroprene polymer constituting the chloroprene polymer latex may be a chloroprene homopolymer, but chloroprene and other copolymerizable monomers such as 2,3-dichloro-1,3-butadiene, 1 Use of a copolymer containing chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, etc., as long as they do not impair the intended performance of the present invention. it can. The ratio of these copolymerizable monomers is 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic esters, methacrylic esters. It is preferable that the content of the acid is 0.01 to 20% by mass and that of acrylic acid and methacrylic acid is 0.01 to 7% by mass.
You may use 2 or more types of monomers which comprise a copolymer as needed. Two or more types of polymers may be mixed to form a chloroprene polymer latex. Among them, the chloroprene polymer constituting the chloroprene polymer latex is a chloroprene homopolymer, a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, a chloroprene homopolymer and chloroprene and 2,3- In the case of a mixture of a copolymer with dichloro-1,3-butadiene, the obtained one-component aqueous adhesive is preferable because it exhibits high adhesive strength.

As chain transfer agents for adjusting the molecular weight and molecular weight distribution, long-chain alkyl mercaptans such as n-dodecyl mercaptan and t-dodecyl mercaptan, and dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide are used. However, it is not limited to these. From the viewpoint of easy control of the molecular weight and gel content, it is preferable to use long-chain alkyl mercaptans. Two or more of these chain transfer agents may be used in combination.

The polymerization conversion ratio of the raw material monomer to the chloroprene polymer in the chloroprene polymer latex is preferably 65% by mass or more and less than 90% by mass. When the polymerization conversion rate is less than 65%, not only does the solid content of the polymer latex decrease, the load is applied to the drying process after application of the adhesive, and the homogenization of the adhesive layer is difficult, It may cause problems such as deterioration of odor, adhesive strength and adhesive strength due to residual monomers. When the polymerization conversion rate is 90% by mass or more, branching increases in the polymer, or the molecular weight distribution increases because the molecular weight increases, and there is a problem of deteriorating contact properties and water resistance, which are important performances in the present invention. It may happen. When a polymer having a conversion rate of 90% by mass or more is used, it is preferably used as an auxiliary component of a polymer having a conversion rate of less than 90% by mass. The polymerization conversion rate (% by mass) is obtained by [(polymer mass / total monomer mass) × 100].

The chloroprene polymer can be polymerized in the range of 5 to 45 ° C., but it is particularly preferable to polymerize at a low temperature of 5 to 20 ° C. The chloroprene homopolymer is known to occupy 85% or more of trans-1,4-bonds, and its molecular structure is relatively regular. Chloroprene homopolymer has properties as a typical crystalline polymer due to the high regularity of this molecular structure. By setting the polymerization temperature to a low temperature of 5 to 20 ° C., the ratio of trans-1,4-bonds in the polychloroprene molecule is further increased, so that a chloroprene homopolymer having a higher crystallization rate can be obtained. Adhesive strength sufficient when this is used as a one-component aqueous adhesive is achieved.

As an initiator for emulsion polymerization, a normal radical polymerization initiator can be used. Specifically, an organic or inorganic peroxide such as benzoyl peroxide, potassium persulfate, or ammonium persulfate, azobisisobutyrate. An azo compound such as ronitrile is used. A promoter such as anthraquinone sulfonate, potassium sulfite, or sodium sulfite may be used in combination as appropriate.

In the production of a chloroprene polymer, for the purpose of obtaining a polymer having a desired molecular weight and distribution, a polymerization terminator is added to stop the reaction when a predetermined polymerization rate is reached. Examples of the polymerization terminator include phenothiazine, pt-butylcatechol, hydroquinone, hydroquinone monomethyl ether, and diethylhydroxylamine.

The solid content concentration of the chloroprene polymer latex is not particularly limited, but is usually 40 to 65% by mass.

Chloroprene-based polymers are generally susceptible to deterioration by oxygen. In the present invention, it is desirable to appropriately use a stabilizer such as an antioxidant as long as the effects of the invention are not impaired. It is possible to improve the temporal stability of the flexibility of the adhesive layer obtained by adding an antioxidant. When the antioxidant is insoluble in water or destabilizes the emulsified state of the chloroprene polymer latex, it may be added to an aqueous dispersion after being prepared in advance.

Examples of the antioxidant include zinc oxide and hydrotalcite (manufactured by Kyowa Chemical Co., Ltd., DHT-4A, DHT-6, etc.). These may be used in combination of two or more. The addition amount of these antioxidants is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 1 part by mass with respect to 100 parts by mass of the solid content of the chloroprene polymer latex. If it is less than 0.01 part by mass, the effect of adding an antioxidant cannot be obtained, and if it exceeds 5 parts by mass, the initial adhesive strength and the normal adhesive strength of the obtained one-component aqueous adhesive may decrease. Moreover, the colloidal stability of the latex composition may be deteriorated and problems such as sedimentation may occur.

(B) Aqueous dispersion The aqueous dispersion comprises (a) a terpene phenol resin emulsion, (b) an acrylic latex having a glass transition temperature (Tg) of −40 to −10 ° C., and (c) a pH of 8.0 to 10. 0.0 and at least one selected from epoxy resin emulsions having a carboxyl group.

(A) Terpene phenol resin emulsion The terpene phenol resin emulsion is a tackifying resin (B-1) having an anionic functional group and no vinyl ether group or vinyl thioether group (hereinafter referred to as “component (B-1)”). ) And a volatile base (B-2) (hereinafter referred to as “component (B-2)”), and a compound (B-3) having a vinyl ether group or vinyl thioether group (hereinafter referred to as “component (B)”). -3) ") is a tackifying resin emulsion in which a composition containing the composition is dispersed in water. The terpene phenol resin emulsion is blended in order to maintain the adhesive holding force of the adhesive using the latex composition and to develop good adhesive strength on various adherends.

The component (B-1) is not particularly limited as long as it is a tackifier resin having an anionic functional group and having no vinyl ether group or vinyl thioether group, and known components can be used. An anionic functional group is a functional group that can release hydrogen to become an anion, such as a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. Hydroxyl groups are preferred. The number of phenolic hydroxyl groups contained in component (B-1) is not particularly limited, but the amount of phenolic hydroxyl groups is usually 5 to 250 mgKOH as the hydroxyl value of the phenolic hydroxyl group of component (B-1). / G is preferable. When the hydroxyl value is less than 5 mgKOH / g, it may be difficult to obtain a sufficient crosslinking density. When the hydroxyl value exceeds 250 mgKOH / g, the resulting film may become brittle and sufficient adhesive strength may not be obtained.

Examples of the component (B-1) include terpene phenol resins.
The terpene phenol resin is a resin obtained by copolymerizing terpenes and phenols. The hydroxyl value of the terpene phenol resin is preferably adjusted to be about 10 to 250 mgKOH / g. These terpene phenol resins have different softening points depending on their types, but usually the softening point is about 30 to 155 ° C. In particular, a material having a temperature of about 60 to 155 ° C. is preferable in terms of good adhesion performance.

Component (B-2) may be any known volatile base, such as ammonia, primary amine, secondary amine, tertiary amine and the like. Primary amines include methylamine, ethylamine, propylamine, butylamine, etc. Secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, etc. Tertiary amines include trimethylamine, triethylamine, tripropylamine, pyridine , Tributylamine, dimethylethanolamine and the like. Among these, tertiary amines, particularly trimethylamine and triethylamine, are preferable because the storage stability of the resulting latex composition is improved.

Component (B-3) may be any component having no anionic functional group and having a vinyl ether group or vinyl thioether group, and in particular, having two or more vinyl ether groups or vinyl thioether groups is obtained. This is preferable because the adhesive holding power of the one-component aqueous adhesive can be increased and various adherends can be bonded. The compound having two or more vinyl ether groups or vinyl thioether groups is represented by the general formula (1)
CH ₂ ═CH—O—CH═CH ₂ (1)
(X represents an alkylene group or an oxyalkylene group. The alkylene group and the oxyalkylene group may have a branched structure and an unsaturated bond, and may have an aromatic group in the chain.) And general formula (2)
CH ₂ ═CH—S—Y—S—CH═CH ₂ (2)
(Y represents an alkylene group or an oxyalkylene group. It may have an alkylene group, an oxyalkylene group branched structure, an unsaturated bond, or may have an aromatic group in the chain). There are compounds represented. Specifically, butanediol divinyl ether, cyclohexane dimethanol divinyl ether, ethylene glycol divinyl ether, tetraethylene glycol divinyl ether, hexanediol divinyl ether, trimethylolpropane trivinyl ether, polytetramethylene glycol divinyl ether, trimethylolpropane trivinyl ether And pentaerythritol tetravinyl ether and polyethylene glycol divinyl ether. Among these, it is preferable to use an alkylene group or an oxyalkylene group having 6 or more carbon atoms because the corrosion resistance and solvent resistance of the obtained one-component aqueous adhesive are improved. Examples of those having 6 or more carbon atoms include cyclohexanedimethanol divinyl ether, triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, hexanediol divinyl ether, trimethylolpropane trivinyl ether, polyethylene glycol divinyl ether, polytetramethylene glycol divinyl ether. And vinyl thioether compounds corresponding thereto, glycerin trivinyl ether, pentaerythritol tetravinyl ether, and the like.

The amount of component (B-1) to component (B-3) used is not particularly limited, but when component (B-1) is not neutralized with component (B-2), component (B-1) And component (B-3) react with each other, it is usually necessary to use component (B-2) in an amount equal to or greater than the anionic functional group of component (B-1). When a compound having an anionic functional group such as an emulsifier is used in addition to the component (B-1), a component that can neutralize the unneutralized anionic functional group contained in the compound (B-2 ) Is preferably used. By using an excessive amount of the component (B-2), it is possible to maintain the adhesive holding force for a long time. The amount of component (B-3) used is not particularly limited, but is usually about 1 to 50% relative to the molar amount of component (B-1). If it is used in a large amount exceeding 50%, the component (B-3) may remain unreacted and adversely affect the adhesion performance, or the compatibility with the chloroprene polymer latex may be reduced. is there. When the content is less than 1%, a sufficient crosslinking effect is not exhibited, and the normal adhesive strength of the obtained one-component aqueous adhesive may be lowered. A terpene phenol resin emulsion may be used in combination with a tackifying resin having no anionic functional group. When a tackifier resin having no anionic functional group is used, the amount used is preferably 50 parts by mass or less with respect to 100 parts by mass of the component (B-1).

When emulsifying component (B-1), if the component (B-1) itself does not have emulsifying ability, an emulsifier is usually used. It does not specifically limit as an emulsifier to use, A well-known emulsifier can be used. Examples of the emulsifier include an anionic emulsifier and a nonionic emulsifier.

Examples of anionic emulsifiers include metals such as organic sulfonic acids and sulfates, or ammonium salts. Specifically, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium oleyl sulfate, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene Sodium oxyethylene oleyl ether sulfate, sodium polyoxyethylene nonylphenyl ether sulfate, sodium polyoxyethylene styryl phenyl ether sulfate, sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, disodium polyoxyethylene lauryl sulfosuccinate, sodium alkyldiphenyl ether disulfonate There is.

Nonionic emulsifiers include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonyl phenyl ether, sorbitan monolaurate, sorbitan trioleate, polyoxyethylene sorbitan monomonolaurate, polyoxyethylene monolaurate, polyoxyethylene monolaurate Examples include oxyethylene monooleate, oleic acid monoglyceride, stearic acid monoglyceride, and polyoxyethylene / polyoxypropylene / block copolymer.

Commercially available terpene phenol resin emulsions include Tamanol E-100 and Tamanol E-200NT manufactured by Arakawa Chemical Industries, Ltd. Although not particularly limited, the viscosity of the terpene phenol resin emulsion used in the present invention is desirably 1000 mPa · s or less from the viewpoint of blending workability. This viscosity was measured with a B-type viscometer (BM type manufactured by Tokyo Keiki Co., Ltd.). It is a value measured at 25 ° C. using two rotors.

(B) Acrylic polymer latex containing an acrylic polymer having a glass transition temperature of −40 to −10 ° C. (hereinafter referred to as “acrylic polymer latex”).
Acrylic polymer latex is formulated to improve adhesion to the adherend and maintain adhesion to various adherends while maintaining the initial adhesive strength of the adhesive using the latex composition. To do.
In general, it is known that when chloroprene polymer latex and acrylic polymer latex are mixed, colloidal stability is deteriorated and aggregation or sedimentation is likely to occur.

In the present invention, an acrylic polymer latex having a glass transition temperature of −40 to −10 ° C. is used in order not to deteriorate the above-mentioned colloidal stability. These acrylic polymer latexes are obtained by (co) polymerizing (meth) acrylic acid esters with a functional group monomer, a room temperature crosslinking group monomer and / or another copolymerizable monomer as required. is there.

(Meth) acrylic acid esters are methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, propyl (meth) acrylate, stearyl (meth) Examples include acrylate and benzyl (meth) acrylate. These can be used alone or in combination of two or more.

Examples of the functional group monomers include (meth) acrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl (meth) acrylate, dimethylaminoethyl methacrylate, 1,6-hexanediol acrylate, and allyl methacrylate. They can be used alone or in combination of two or more. The content of the functional group monomer in the copolymer is preferably 7% by mass or less, and more preferably 5% by mass or less. If it exceeds 7% by mass, it may become unstable and easily gelled.

The room temperature crosslinking group monomers include adipic acid dihydrazide, glutaric acid dihydrazide, isophthalic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide , 2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazide and the like, and these can be used alone or in combination of two or more. The content of the room temperature crosslinking group monomer unit in the copolymer is preferably 20% by mass or less. When the amount is more than 10% by mass, the effect of improving the initial adhesive force may be reduced.

Examples of the other copolymerizable monomer include (meth) acrylonitrile, styrene, vinyl acetate, and allyl alcohol. These can be used alone or in combination of two or more. The content of other copolymerizable monomer units in the copolymer is preferably 10% by mass or less, and more preferably 5% by mass or less. If it exceeds 10% by mass, it may become unstable and easily gelled.

The acrylic polymer latex is obtained by polymerizing these monomer components by a known emulsion polymerization method. The conditions for the emulsion polymerization are 100 to 900 parts by weight of water with respect to 100 parts by weight of the total monomer components. In general, the polymerization is carried out at a polymerization temperature of generally 10 to 90 ° C., preferably 40 to 80 ° C., usually for 3 to 15 hours.

The glass transition temperature of the acrylic polymer in the acrylic polymer latex is −40 to −10 ° C., preferably −35 to −15 ° C. If it is less than -40 ° C, the initial adhesive force deteriorates as the cohesive force decreases. When the temperature exceeds -10 ° C, the tackiness is lost, and the initial adhesive force and the contact property are remarkably deteriorated.

The glass transition point of the acrylic polymer latex is a value measured under the following conditions using a differential scanning calorimeter (DCS) manufactured by Rigaku Corporation.
1. About 5 g of acrylic latex (in terms of solid content) is thinly stretched on a glass plate and dried at 25 ° C. for 7 days to obtain a polymer film.
2. The glass transition point of the obtained dry film is measured. Specifically, the measurement was performed at a sample amount of 20 mg, under a nitrogen atmosphere, and at a temperature rising rate of 20 ° C./min.

The solid content concentration of the acrylic polymer latex is not particularly limited, but is usually 35 to 65% by mass.

The viscosity of the acrylic latex used in the present invention is not particularly limited, but is preferably 1000 mPa · s or less from the viewpoint of workability of the blend. This viscosity was measured with a B-type viscometer (BM type manufactured by Tokyo Keiki Co., Ltd.). It is a value measured at 25 ° C. using two rotors.

Commercially available acrylic resin latexes include AE-337 manufactured by Etec Co., Ltd., Nipol LX874 manufactured by Nippon Zeon Co., Ltd., and FK-474 manufactured by Chuo Rika Kogyo Co., Ltd.

(C) An epoxy resin emulsion having a carboxyl group with a pH of 8.0 to 10.0 (hereinafter referred to as “aqueous epoxy resin emulsion”).
The aqueous epoxy resin emulsion is blended in order to increase the adhesion of the one-pack type water-based adhesive using the latex composition and to increase the adhesive strength to the cloth material, leather material and paper material of handbags and shoe products.
Generally, an epoxy resin emulsion is subjected to a crosslinking reaction with a curing agent to form a coating film or an adhesive layer. As the curing agent, amine compounds, thiol compounds, dicyandiamide, acid anhydrides, imidazoles, etc. are widely used. When these are blended directly into chloroprene polymer latex, colloidal stability deteriorates and aggregation and sedimentation occur. It becomes easy to cause.

In the present invention, an epoxy resin emulsion having a pH of 8.0 to 11.0 and having a carboxyl group is used in order not to deteriorate the above-mentioned colloidal stability.

The aqueous epoxy resin emulsion used in the present invention includes a bisphenol-type epoxy resin, an aliphatic epoxy resin, a polymerizable unsaturated group-containing modified epoxy resin obtained by reacting a glycidyl group-containing vinyl monomer and a carboxyl group-containing vinyl monomer. An emulsion obtained by neutralizing a modified epoxy resin obtained by copolymerization with a basic compound and dispersing in water, and a vinyl-modified epoxy resin emulsion characterized by having a pH of 8.0 to 10.0. is there.

The bisphenol-type epoxy resin is not particularly limited, and various known ones can be used. Specific examples include reaction products of bisphenols and haloepoxides such as epichlorohydrin or β-methylepichlorohydrin. Examples of the bisphenols include reaction products of phenol or 2,6-dihalophenol with aldehydes or ketones such as formaldehyde, acetaldehyde, acetone, acetophenone, cyclohexane, benzophenone, dihydroxyphenyl sulfide peroxide, hydroquinone The etherification reaction product of

The aliphatic epoxy resin is not particularly limited as long as it is an epoxy resin that does not contain an aromatic ring and a vinyl group in the molecule, and various known resins can be used. Specific examples include glycidyl ethers of polyhydric alcohols. Examples of the polyhydric alcohol include 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, cyclohexanedimethanol, hydrogenated bisphenol, and polyalkylene glycols having an alkylene glycol structure. Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, polybutylene glycol, and the like. In addition to the glycidyl ethers of polyhydric alcohols, known epoxy resins such as polybutadiene diglycidyl ether can also be used.

As the glycidyl group-containing vinyl monomer, various known compounds containing glycidyl group and polymerizable vinyl group in the molecule, other than the bisphenol type epoxy resin and the aliphatic epoxy resin, There is no particular limitation. Specific examples include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, (meth) acrylicidyl ether, and the like.

As said amines, well-known amines other than the said bisphenol-type epoxy resin, the said aliphatic epoxy resin, and the said glycidyl group containing vinyl monomer can be especially used without a restriction | limiting. For example, there are alkanolamines, aliphatic amines, aromatic amines, alicyclic amines, aromatic nucleus-substituted aliphatic amines, and the like, which can be used by appropriately selecting one kind or two or more kinds. Specifically, examples of the alkanolamines include ethanolamine, diethanolamine, diisopropanolamine, di-2-hydroxybutylamine, N-methylethanolamine, N-ethylethanolamine, N-benzylethanolamine and the like. Aliphatic amines include primary amines such as ethylamine, propylamine, butylamine, hexylamine, laurylamine, stearylamine, palmitylamine, oleylamine and erucylamine, and secondary amines such as diethylamine, dipropylamine and dibutylamine. There are secondary amines. Examples of aromatic amines include toluidines, xylidines, cumidine (isopropylaniline), and hexylanilines include cyclopentylamines, cyclohexylamines, and norbornylamines. Aromatic nucleus-substituted aliphatic amines include benzylamine and phenethylamine. *

The amount of the aliphatic epoxy tree species added to the aqueous epoxy resin emulsion is 5 to 40% by weight of the total amount of the bisphenol type epoxy resin and the aliphatic epoxy resin. By adjusting the content to 5 to 40% by weight, the adhesive layer is appropriately soft and exhibits good adhesion to flexible adherends such as cloth materials, leather materials, paper materials, and the like. Strength can be improved. In particular, the content is preferably 10 to 30% by weight. The addition amount of the glycidyl group-containing vinyl monomer is not particularly limited, but usually the epoxy equivalent is 1 to 25 equivalents with respect to 100 equivalents of the total epoxy groups of the bisphenol type epoxy resin and the aliphatic epoxy resin. It is preferable to be used for. When the epoxy equivalent of the glycidyl group-containing vinyl monomer is 1 or less, the storage stability of the resulting vinyl-modified epoxy resin emulsion is poor, and when it is 25 equivalents or more, the probability of gelation increases and the storage stability deteriorates. To do. The amines are added to the amino groups of the amines with respect to 100 equivalents of the total epoxy groups contained in the bisphenol-type epoxy resin, the aliphatic epoxy resin, and the glycidyl group-containing vinyl monomer. It is preferably used so that the equivalent amount of the active hydrogen derived is from 90 to 110 equivalents.

The aqueous epoxy resin emulsion can be easily produced by heating each component in the presence of an organic solvent. The reaction temperature is usually about 60 to 200 ° C., but if the reaction temperature is too low, unreacted epoxy groups tend to remain, so it is preferably 80 ° C. or higher. On the other hand, if the reaction temperature is too high, the reaction product tends to gel due to the ring-opening reaction between the epoxy group in the vinyl-modified epoxy resin component and the hydroxyl group in the other component, or the ring-opening reaction between epoxies, It is preferable to set it to 150 ° C. or lower. The reaction time depends on the reaction temperature, but it is preferably about 3 to 10 hours under the above temperature conditions.

The organic solvent is not particularly limited and a known one can be used, but it is preferable to use a hydrophilic solvent from the viewpoint of making the finally obtained aqueous epoxy resin aqueous. Specifically, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-butyl ether, propylene glycol mono t-butyl ether, methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, t-butyl cellosolve, isopropyl alcohol, butyl alcohol, etc. There is.

The aqueous epoxy resin emulsion used in the present invention is obtained by copolymerizing the above polymerizable unsaturated group-containing epoxy resin and a carboxyl group-containing vinyl monomer.

The carboxyl group-containing vinyl monomer is not particularly limited, and specific examples include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, and the like, and at least one of these is selected. be able to.

The carboxyl group-containing vinyl monomer is essential for facilitating aqueous formation (water dispersion or dissolution in stability) of the aqueous epoxy resin obtained. Therefore, the amount of the carboxyl group-containing vinyl monomer used is determined from the viewpoint of making the resulting vinyl-modified epoxy resin aqueous, and usually has a solid content acid value of 10 mgKOH / g or more, and more preferably 20 mgKOH / g or more. It is preferable to adjust so that. On the other hand, in order to give good water resistance to the water-based epoxy resin, it is usually preferable that the solid acid value of the water-based epoxy resin is 40 mgKOH / g or less.

The weight ratio of the polymerizable unsaturated group-containing modified epoxy resin to the carboxyl group-containing vinyl monomer (polymerizable unsaturated group-containing modified epoxy resin / carboxyl group-containing vinyl monomer) is obtained as described above. Although it can be conveniently determined in consideration of the solid content acid value of the unsaturated group-containing modified epoxy resin, it is preferably 90/10 to 80/20. If the amount of the carboxyl group-containing vinyl monomer used is less than the lower limit, water dispersibility or water solubility becomes unstable, and the product tends to precipitate. Moreover, when a carboxyl group-containing vinyl monomer exceeds the said upper limit, there exists a tendency for the adhesiveness which is the original characteristic of a water-based epoxy resin to fall.

The aqueous epoxy resin obtained as described above is neutralized with a basic compound and dissolved or dispersed in water to obtain a desired aqueous epoxy resin emulsion. That is, it is preferable to neutralize all or part of the carboxyl groups derived from the carboxyl group-containing vinyl monomer in the aqueous epoxy resin so that the pH is about 8.0 to 11.0. Considering the case of blending, 9.0 to 11.0 is particularly preferable. As the basic compound which is a neutralizing agent, amines such as ammonia, triethylamine and dimethylethanolamine, alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, and the like can be used. In consideration, ammonia and amines are preferable.

Examples of commercially available epoxy resin emulsions include Modelix 301, Modelix 302, and Modelix 304 manufactured by Arakawa Chemical Industries, Ltd.

These (B) terpene phenol resin emulsions, at least one selected from acrylic latexes having a glass transition temperature (Tg) of −40 to −10 ° C. and epoxy resin emulsions having a pH of 8.0 to 10.0 and having carboxyl groups The amount of the aqueous dispersion blended is (A) 10 to 50 parts by mass in total (solid content conversion) with respect to 100 parts by mass in terms of solid content of chloroprene polymer latex having a pH of 12 or more.
When the blending amount of the aqueous dispersion (B) is less than 10 parts by mass, the tackiness of the one-component aqueous adhesive using a latex mixture is inferior, and various adherends may not be bonded. is there. If the blending amount exceeds 50 parts by mass, the normal adhesive strength of the one-component aqueous adhesive may be lowered, or the storage stability of the adhesive may be deteriorated. A preferable range of the blending amount is 10 to 30 parts by mass with respect to 100 parts by mass in terms of solid content of the chloroprene polymer latex.

In the latex composition of the present invention, in addition to the aforementioned components (A) and (B), (C) zinc white is added in an amount of 0.5 to 100 parts by mass (solid content) as required. It can be added in an amount of 10 parts by mass, more preferably 1 to 5 parts by mass. If the amount of zinc white added is small, the adhesive strength may be reduced. If the amount of zinc white added is large, the initial adhesive strength may be reduced or the cost may be disadvantageous.

As the zinc white, known zinc white can be used. The number average particle size of zinc white is particularly preferably in the range of 0.1 to 0.3 μm. The number average particle size of zinc white is determined by 200 observation images of zinc white powder obtained by ultrasonically dispersing in water and then naturally drying, using an SEM device (FE-SEM SU6600: manufactured by Hitachi High-Technologies Corporation). It is the number average value of the direction tangent diameter (Feret diameter). Using zinc white with a number average particle size of less than 0.1 μm causes the zinc white to aggregate, making it difficult to uniformly disperse in the latex composition, and the zinc white itself tends to scatter, thus reducing handling. To do. If the number average particle diameter exceeds 0.3 μm, the adhesive strength may not be improved.

The zinc oxide particularly effective in the present invention has a specific surface area of 15 to 25 m ² / g or less. Here, the specific surface area of zinc white is JIS-Z8830 using a specific surface area measuring device (Monosorb: manufactured by QUANTACHROME INSTRUMENTS) using a powder obtained by ultrasonically dispersing zinc white in water and then air-drying it as a sample. It is a value measured by the BET method using nitrogen as an adsorbate in conformity. If the specific surface area of zinc white is less than 15 m ² / g, the adhesive strength of the one-pack type aqueous adhesive obtained by not being able to promote the crosslinking of the chloroprene polymer may not be improved. Zinc flower having a specific surface area of more than 25 m ² / g is difficult to use in industrial production because it tends to absorb moisture and deteriorate the quality of zinc flower itself.

Examples of zinc white that satisfy the above conditions of the number average particle diameter and specific surface area include zinc white by a wet production method obtained by reacting a reaction solution comprising an inorganic zinc salt aqueous solution and an alkaline aqueous solution in a stirred reaction tank. In order to facilitate uniform mixing of zinc white, it can be previously dispersed in water before being added to the chloroprene latex. As an emulsifier for dispersing zinc white in water, a general anionic emulsifier can be used. 1 (trade name, manufactured by RT Verderbilt Company).

Commercially available products of zinc white include AZ-SW manufactured by Osaki Kogyo Co., Ltd. and META-Z Inoue Lime Co., Ltd.

Furthermore, the latex composition of the present invention preferably contains (D) a hindered phenol-based antioxidant. The hindered phenol-based antioxidant has an effect of improving discoloration and hygiene of the protruding portion of the adhesive paste when the latex composition is used as an adhesive. The hindered phenol antioxidants are 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4,4′- Examples include butylidenebis (3-methyl-6-tert-butylphenol), butylated reaction product of p-cresol and dicyclopentadiene. The amount of the hindered phenol-based antioxidant added is preferably 0.1 to 3% by mass, more preferably 0.5 to 2% by mass, based on 100 parts by mass of the solid content of the latex composition. When the addition amount of the hindered phenol antioxidant is less than 0.1% by mass, the antioxidant effect is not sufficient. Conversely, when it exceeds 3% by mass, the adhesive strength and the adhesive strength may be deteriorated.

In the latex composition, fillers, tackifiers, pigments, colorants, wetting agents, antifoaming agents, thickeners and the like are appropriately used as additives other than the above as long as the effects of the present invention are not impaired. be able to. In addition, other resin emulsions (latex) may be supplementarily blended with the upper limit of 10% by mass (in terms of solid content) of the total composition. Specifically, there are resin emulsions such as (modified) vinyl acetate, vinyl acetate / acrylic mixed, acrylic / styrene mixed, and urethane.

Hereinafter, the present invention will be described specifically by way of examples. These examples do not limit the invention. In the following examples, “part” and “%” are based on mass unless otherwise specified.

[Experimental Example 1]
Production of chloroprene polymer latex (A1) Using a reactor having an internal volume of 3 liters, under a nitrogen stream, 100 parts of pure water, 5 parts of sodium rosinate, 0.5 parts of potassium hydroxide, formaldehyde naphthalenesulfonic acid condensate 0.3 part of sodium salt and 0.3 part of sodium hydrogen sulfite were charged, and after dissolution, 100 parts of chloroprene monomer and 0.06 part of n-dodecyl mercaptan were added with stirring. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using 0.1 part by weight of potassium persulfate as an initiator. When the final polymerization rate reached 78%, an emulsion of phenothiazine was added to terminate the polymerization. After removing the unreacted monomer under reduced pressure, 0.3 part of polyoxyalkylene alkyl ether as a low temperature stabilizer was added to 100 parts of solid content while stirring. Further, the water was evaporated under reduced pressure to perform concentration, and the solid content concentration was adjusted to 55% by mass to obtain a chloroprene polymer latex (A1). The gel content of the chloroprene polymer latex (A1) was 5%, the Mn content of toluene-soluble matter was 300,000, and the molecular weight distribution (Mw / Mn) was 2.5.

[Experiment 2]
Production of chloroprene polymer latex (A2) Using a reactor having an internal volume of 3 liters, under a nitrogen stream, 100 parts pure water, 5 parts sodium rosinate, 0.5 parts potassium hydroxide, formaldehyde naphthalene sulfonic acid condensate 0.3 part of sodium salt and 0.3 part of sodium hydrogen sulfite were charged, and after dissolution, 100 parts of chloroprene monomer and 0.06 part of n-dodecyl mercaptan were added with stirring. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using 0.1 part by weight of potassium persulfate as an initiator. When the final polymerization rate reached 85%, an emulsion of phenothiazine was added to terminate the polymerization. After removing the unreacted monomer under reduced pressure, 0.3 part of polyoxyalkylene alkyl ether as a low temperature stabilizer was added to 100 parts of solid content while stirring. Further, the water was evaporated under reduced pressure to perform concentration, and the solid content concentration was adjusted to 55% by mass to obtain a chloroprene polymer latex (A2). The gel content of the chloroprene polymer latex (A2) was 30%, the Mn content of toluene-soluble matter was 300,000, and the molecular weight distribution (Mw / Mn) was 2.5.

[Experiment 3]
Production of chloroprene polymer latex (A3) Using a reactor having an internal volume of 3 liters, under a nitrogen stream, 100 parts pure water, 5 parts sodium rosinate, 0.5 parts potassium hydroxide, formaldehyde naphthalenesulfonic acid condensate 0.3 part of sodium salt and 0.3 part of sodium hydrogen sulfite were charged, and after dissolution, 100 parts of chloroprene monomer and 0.14 part of n-dodecyl mercaptan were added with stirring. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using 0.1 part by weight of potassium persulfate as an initiator. When the final polymerization rate reached 80%, an emulsion of phenothiazine was added to terminate the polymerization. After removing the unreacted monomer under reduced pressure, 0.3 part of polyoxyalkylene alkyl ether as a low temperature stabilizer was added to 100 parts of solid content while stirring. Further, the water was evaporated under reduced pressure to perform concentration, and the solid content concentration was adjusted to 55% by mass to obtain a chloroprene polymer latex (A3). The gel content of the chloroprene polymer latex (A3) was 15%, the toluene soluble Mn was 100,000, and the molecular weight distribution (Mw / Mn) was 2.5.

[Experimental Example 4]
Production of chloroprene polymer latex (A4) Using a reactor having an internal volume of 3 liters, in a nitrogen stream, 100 parts of pure water, 5 parts of sodium rosinate, 0.5 parts of potassium hydroxide, formaldehyde naphthalenesulfonic acid condensate 0.3 parts of sodium salt and 0.3 parts of sodium hydrogen sulfite were charged, and after dissolution, 100 parts of chloroprene monomer and 0.10 parts of n-dodecyl mercaptan were added with stirring. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using 0.1 part by weight of potassium persulfate as an initiator. When the final polymerization rate reached 80%, an emulsion of phenothiazine was added to terminate the polymerization. After removing the unreacted monomer under reduced pressure, 0.3 part of polyoxyalkylene alkyl ether as a low temperature stabilizer was added to 100 parts of solid content while stirring. Further, the water was evaporated under reduced pressure to perform concentration, and the solid content concentration was adjusted to 55% by mass to obtain a chloroprene polymer latex (A4). The gel content of the chloroprene-based polymer latex (A4) was 15%, the Mn of the toluene-soluble component was 250,000, and the molecular weight distribution (Mw / Mn) was 2.5.

[Experimental Example 5]
Production of chloroprene polymer latex (A5) Using a reactor having an internal volume of 3 liters, under a nitrogen stream, 100 parts of pure water, 5 parts of sodium rosinate, 0.5 parts of potassium hydroxide, formaldehyde naphthalenesulfonic acid condensate 0.3 part of sodium salt and 0.3 part of sodium hydrogen sulfite were charged, and after dissolution, 100 parts of chloroprene monomer and 0.12 part of n-dodecyl mercaptan were added with stirring. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using 0.1 part by weight of potassium persulfate as an initiator. When the final polymerization rate reached 72%, an emulsion of phenothiazine was added to terminate the polymerization. After removing the unreacted monomer under reduced pressure, 0.3 part of polyoxyalkylene alkyl ether as a low temperature stabilizer was added to 100 parts of solid content while stirring. Further, the water was evaporated under reduced pressure to perform concentration, and the solid content concentration was adjusted to 55% by mass to obtain a chloroprene polymer latex (A5). The gel content of the chloroprene polymer latex (A5) was 0%, the Mn of the toluene-soluble component was 120,000, and the molecular weight distribution (Mw / Mn) was 2.7.

[Experimental Example 6]
Production of chloroprene polymer latex (A6) Using a reactor having an internal volume of 3 liters, in a nitrogen stream, 100 parts pure water, 5 parts sodium rosinate, 0.5 parts potassium hydroxide, formaldehyde naphthalenesulfonic acid condensate 0.3 part of sodium salt and 0.3 part of sodium hydrogen sulfite were charged, and after dissolution, 100 parts of chloroprene monomer and 0.06 part of n-dodecyl mercaptan were added with stirring. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using 0.1 part by weight of potassium persulfate as an initiator. When the final polymerization rate reached 90%, an emulsion of phenothiazine was added to terminate the polymerization. After removing the unreacted monomer under reduced pressure, 0.3 part of polyoxyalkylene alkyl ether as a low temperature stabilizer was added to 100 parts of solid content while stirring. Further, the water was evaporated under reduced pressure to perform concentration, and the solid content concentration was adjusted to 55% by mass to obtain a chloroprene polymer latex (A6). The gel content of the chloroprene polymer latex (A6) was 40%, the Mn of the toluene-soluble component was 120,000, and the molecular weight distribution (Mw / Mn) was 2.8.

The gel content, the Mn (number average molecular weight) of toluene-soluble matter, and the molecular weight distribution (Mw / Mn) of these chloroprene polymer latexes (A1) to (A6) are values measured by the following methods.
[Gel content]
After each sample was freeze-dried, the data was precisely weighed and designated as X. This was dissolved in toluene (prepared to 0.6%), and after using a centrifuge, the gel content was separated using a 200-mesh wire mesh. The separated gel was air-dried and then dried in an atmosphere at 110 ° C. for 1 hour.

The gel content was calculated by the following formula.

[Mn and molecular weight distribution of toluene-soluble matter (Mw / Mn)]
GPC measurement was performed under the following conditions, the molecular weight in terms of polystyrene was measured, and the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were evaluated. The measurement was carried out by preparing the toluene soluble component (sol) separated by the gel content measurement in a 0.1% tetrahydrofuran (THF) solution.

Measuring device: HLC-8120GPC manufactured by Tosoh Corporation
Analysis column: Tosoh TSK-GEL GMH _HR -H (5 μm) × 3, size 7.8 mmφ × 300 mm
Guard column: guard column TSK-guard column TSK-guard column H _HR -H (5 μm), size 6 mmφ × 40 mm
Column temperature: 40 ° C
Solvent: THF special grade, flow rate: 1 ml / min

[Terpene phenol resin emulsion]
The following were used for the terpene phenol resin emulsion (BI) and the rosin ester resin (BII) blended in the chloroprene polymer latexes of Examples and Comparative Examples.
BI: Tamanoru E-100: (Arakawa Chemical Industries, Ltd.)
BII: Superester E-650: (Arakawa Chemical Industries, Ltd.)

[Acrylic latex]
The acrylic latexes (BIII) to (BV) blended in the chloroprene polymer latexes of Examples and Comparative Examples were as follows.
BIII: AE-337 (Tg = −30 ° C.) (manufactured by Etec Co., Ltd.)
BIV: Nipol LX874 (Tg = −31 ° C.) (manufactured by Nippon Zeon Co., Ltd.)
BV: Nipol LX844C (Tg = 32 ° C.) (manufactured by Nippon Zeon Co., Ltd.)

The pH, viscosity (mPa · s), solid content concentration (mass%), and Tg (glass transition point) of the acrylic latexes BIII to BV were measured by the following methods, and the measured values are shown in Table 1.

[PH]
The pH of the chloroprene polymer latex and the adhesive composition was measured using a pH meter F-22 manufactured by Horiba, Ltd. after adjusting the temperature of the chloroprene polymer latex to 20 ° C.

[viscosity]
Using a B-type viscometer (RB-L80 type viscometer: manufactured by Toki Sangyo Co., Ltd.), No. Viscosity η ₃₀ at ₃₀ rpm measured under the conditions of 1 rotor, 60 seconds, and 25 ° C. was measured.

[Solid content]
The mass of the aluminum dish alone is α, the mass of the aluminum dish containing 2 ml of the polychloroprene latex sample is β, the mass after drying the aluminum dish containing the latex sample at 110 ° C. for 3 hours is γ, and calculated by the following formula: did.
Solid content concentration (mass%) = {(γ−α) / (β−α)} × 100

[Tg]
The glass transition point is a value [glass transition temperature] given as a baseline variation measured using a thermal differential scanning calorimeter (DSC) (EXSTAR6000 DCS6200R, Seiko Instrument Inc). The glass transition point was measured by allowing the sample to stand at 23 ° C. for 30 minutes and then −10 ° C./min. The temperature was lowered to −100 ° C. and allowed to stand for 10 minutes, and then differential thermal analysis was performed when the temperature was raised from −100 ° C. to 100 ° C. under a temperature rising rate of 20 ° C./min. Measurement conditions other than the rate of temperature increase are based on JIS K7121.

[Epoxy resin emulsion]
The epoxy resin emulsions (BVI) to (BVII) blended in the chloroprene polymer latexes of Examples and Comparative Examples were as follows.
BVI: MODEPICS 302 (Arakawa Chemical Industries, Ltd., pH = 9.7, containing carboxyl group)
BVII: Adeka Resin EM-058 (manufactured by ADEKA Corporation, pH = 7.4)

[Zinc flower]
The followings were used for the zinc white blended in the chloroprene polymer latexes of Examples and Comparative Examples.
Zinc flower: AZ-SW (Osaki Kogyo Co., Ltd .; water dispersion type zinc flower, solid content 50%)

[Preparation of one-component water-based adhesive]
With the blending amounts shown in Tables 2 to 8, chloroprene polymer latex (solid content conversion) and at least one aqueous dispersion selected from terpene phenol resin emulsion, acrylic latex, and epoxy resin emulsion (solid content conversion) ) And zinc white water dispersion (solid content conversion) were blended to prepare one-component aqueous adhesives of Examples 1-44 and Comparative Examples 1-31.
The normal adhesive strength of the obtained one-component aqueous adhesive was measured by the following method. The measurement results are shown in Tables 2 to 8.

(Normal adhesive strength)
To each adherend for evaluation (length 120 mm × width 20 mm), a one-pack type adhesive was applied to both adherends with a commercially available brush at 23 ° C. so as to be 150 g / m ² . After application, the film was dried for 3 hours in an atmosphere of 50% humidity and 23 ° C. After drying, it was again applied to both adherends with a commercially available brush so as to be 150 g / m ² and dried at 60 ° C. for 10 minutes. After drying, the two adherends were bonded together, and after 7 days, the 180 ° peel strength was measured using a tensile tester under the condition of a tensile rate of 200 mm / min.

(Adherent)
As an adherend for evaluating the present invention, nylon cloth, polyurethane cloth, non-woven cloth, and polyurethane cloth were used as the cloth material, bran paper was used as the paper material, and genuine leather and artificial leather were used as the leather material.

Nylon cloth is mainly made of commercially available cloth using nylon 66 fiber, polyurethane cloth is made of commercially available cloth mainly using spandex fiber, and non-woven cloth is made of cotton or silk. It was used. When a nylon cloth was used for the adherend, the case of 0.3 N / mm or more was accepted, and when a polyurethane cloth was used for the adherend, 1.0 N / mm or more was accepted. When the nonwoven fabric was used, the case where the nonwoven fabric broke the material was described as acceptable (O), and the case where the interface peeled without breaking the material was described as unacceptable (x).

The bran paper used was a grade advocated by the Japan Coffee Promotion Association and classified as NFS-20, a popular textile. When bran paper was used, the case where the bran paper broke the material was described as acceptable (◯), and the case where the material peeled without breaking the material was described as unacceptable (x).

The leather used was cowhide, an adult cow's leather that had been born two years after birth. For the artificial leather, a non-woven fabric made of polyester was used as the base fabric, and a polyurethane resin was infiltrated into the base fabric to create a structure and texture similar to natural leather.

Priorities when judging the acceptance criteria of adhesive strength are the presence or absence of material destruction of the nonwoven fabric and bran paper, 0.3 N / mm or more when using nylon cloth, the nonwoven fabric used in this example and comparative example, Judgment was made in the order of 1.0 N / mm or more for adherends other than bran paper and nylon cloth.

As shown in the evaluation results of Tables 2 to 8, the one-component aqueous adhesives of Examples 1 to 44 having the blending composition within the specified range according to the present invention had good normal adhesive strength for any combination of adherends. It was. On the other hand, the blending ratio specified by the present invention is within the specified range, but the characteristics of the chloroprene polymer latex, terpene phenol resin emulsion, acrylic latex, and aqueous epoxy resin emulsion are out of specification. For Nos. 1 to 24, it was not possible to satisfy the acceptance criteria for adhesive strength defined in the present invention for all of the adherends used.
Further, even in Comparative Examples 25 to 31 that include the provision of the present invention but whose blending amount is out of the prescribed range, it is possible to satisfy the pass standard of adhesive strength defined in the present invention for all the adherends used. could not.

Claims (5)

1. (A) 100 parts by mass of chloroprene polymer latex having a pH of 12 or more, (B) terpene phenol resin emulsion, acrylic latex having a glass transition temperature (Tg) of −40 to −10 ° C., and pH A latex mixture containing at least one aqueous dispersion selected from epoxy resin emulsions having a carboxyl group of 8.0 to 10.0 in total in terms of solid content of 10 to 50 parts by mass.
2. The chloroprene polymer contained in the chloroprene polymer latex has a gel content (toluene insoluble content) of 5 to 30% by mass, a toluene soluble content number average molecular weight of 200,000 to 500,000, and a molecular weight distribution (Mw / Mn 2. The latex composition according to claim 1, which is 2.0 to 4.0.
3. The chloroprene polymer contained in the chloroprene polymer latex is a chloroprene homopolymer, a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, or a chloroprene homopolymer and chloroprene and 2, The latex composition according to claim 1 or 2, which is a mixture of a copolymer with 3-dichloro-1,3-butadiene.
4. A one-part aqueous adhesive comprising the latex composition according to claims 1 to 3.
5. The one-pack type aqueous adhesive according to claim 4, which is used for heels or shoes.