阅读说明：本技术 胶乳组合物和膜成型体 (Latex composition and film molded article ) 是由 北川昌 于 2019-02-06 设计创作，主要内容包括：本发明提供一种胶乳组合物,其含有含羧基共轭二烯系橡胶(A)的胶乳、水溶性的金属化合物(B)和包含元素周期表第4族过渡金属的非水溶性的金属化合物(C),上述金属化合物(C)的含量相对于100重量份的上述含羧基共轭二烯系橡胶(A)为0.5～4重量份。(The present invention provides a latex composition comprising a latex of a carboxyl group-containing conjugated diene rubber (A), a water-soluble metal compound (B), and a water-insoluble metal compound (C) containing a transition metal of group 4 of the periodic Table, wherein the content of the metal compound (C) is 0.5 to 4 parts by weight relative to 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A).)

1. A latex composition comprising a latex of a carboxyl group-containing conjugated diene rubber A, a water-soluble metal compound B and a water-insoluble metal compound C containing a transition metal of group 4 of the periodic Table,

the content of the metal compound C is 0.5 to 4 parts by weight relative to 100 parts by weight of the carboxyl group-containing conjugated diene rubber A.

2. The latex composition of claim 1, wherein the metal compound B is an aluminum compound.

3. The latex composition according to claim 1 or 2, wherein the metal compound B is sodium aluminate.

4. The latex composition according to any one of claims 1 to 3, wherein the content of the metal compound B is 0.1 to 1.5 parts by weight relative to 100 parts by weight of the carboxyl group-containing conjugated diene rubber A.

5. The latex composition according to any one of claims 1 to 4, wherein the metal compound C is titanium dioxide or zirconium dioxide.

6. The latex composition according to any one of claims 1 to 5, wherein the content of the metal compound C is 1.5 to 3 parts by weight relative to 100 parts by weight of the carboxyl group-containing conjugated diene rubber A.

7. A film-formed product formed from the latex composition according to any one of claims 1 to 6.

8. A process for producing a dip-molded article, comprising the step of dip-molding the latex composition according to any one of claims 1 to 7.

Technical Field

The present invention relates to a slurry composition and a film molded article such as a dip molded article obtained using the slurry composition, and more particularly, to a latex composition capable of providing a film molded article such as a dip molded article which can suppress the occurrence of immediate hypersensitivity (I-type) and delayed hypersensitivity (IV-type), has high tensile strength, has high stress holding ratio, and can suppress the occurrence of curling winding failure, and a film molded article such as a dip molded article obtained using the latex composition.

Background

Conventionally, there have been known dip-molded articles for use in contact with the human body, such as nipples, balloons, gloves, airbags, and bags, which are obtained by dip-molding a latex composition containing a natural rubber latex, which is represented by a natural rubber latex. However, since the latex of natural rubber contains a protein that causes a symptom of immediate hypersensitivity (type I) in a human body, there is a problem in that the latex is a dip-molded article that directly contacts living mucous membranes or organs. Therefore, a latex using a synthetic rubber such as nitrile rubber has been studied.

For example, patent document 1 discloses a latex composition containing a carboxylated nitrile butadiene random terpolymer of acrylonitrile, a carboxylic acid and butadiene, wherein zinc oxide, sulfur and a vulcanization accelerator are added to an emulsion containing 15 to 25 wt% of the total solid content. However, although the technique of patent document 1 can prevent the occurrence of immediate allergy (type I), when the impregnated molded article is produced, the allergic symptoms of delayed allergy (type IV) may be caused when the impregnated molded article is brought into contact with a human body due to sulfur and a vulcanization accelerator contained in the impregnated molded article.

In contrast, for example, patent document 2 discloses the following technique: in a latex composition containing at least 1 base polymer, a crosslinking agent, and a pH adjusting agent, a mixture of a 3-valent metal or a 3-valent metal-based compound, a specific polyethylene glycol or a polyethylene glycol derivative, and a specific hydroxide salt is used as the crosslinking agent. According to the technique of patent document 2, since sulfur and a sulfur compound as a vulcanization accelerator are not contained, not only the occurrence of immediate allergy (type I) but also the occurrence of delayed allergy (type IV) can be suppressed.

Disclosure of Invention

Problems to be solved by the invention

On the other hand, when a film molded product such as a dip molded product is obtained by dip molding, a sleeve portion of a dip molded layer formed on a dip molding die is generally subjected to a curling process (sleeve rolling process) as a grip portion for releasing from the dip molding die. In particular, when the dip-molded article is used for gloves or the like, such a hemming process is preferably performed in terms of being less likely to be broken when worn and being easy to wear. Under such circumstances, the present inventors have conducted studies and as a result, according to the technique of patent document 2, while it is possible to suppress not only the occurrence of immediate allergy (type I) but also the occurrence of delayed allergy (type IV), there is a problem that when the obtained dip-molded article is subjected to hemming, cracking occurs, the adhesion between the dip-molded layer and the dip-molding die is too high, and the hemming winding operation cannot be performed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a latex composition capable of forming a film molded article such as a dip molded article which can suppress the occurrence of immediate hypersensitivity (I type) and delayed hypersensitivity (IV type), has high tensile strength, has high stress holding ratio, and can suppress the occurrence of defective curling and winding, and a film molded article such as a dip molded article obtained using such a latex composition.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that the above object can be achieved by a latex composition obtained by adding a water-soluble metal compound and a water-insoluble metal compound containing a predetermined amount of a transition metal of group 4 of the periodic table to a latex of a carboxyl group-containing conjugated diene rubber, and have completed the present invention.

That is, according to the present invention, there is provided a latex composition comprising a latex of a carboxyl group-containing conjugated diene rubber (a), a water-soluble metal compound (B), and a water-insoluble metal compound (C) containing a transition metal of group 4 of the periodic table, wherein the content of the metal compound (C) is 0.5 to 4 parts by weight based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a).

In the present invention, the metal compound (B) is preferably an aluminum compound.

In the present invention, the water-soluble metal compound (B) is preferably sodium aluminate.

In the present invention, the content of the water-soluble metal compound (B) is preferably 0.1 to 1.5 parts by weight based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a).

In the present invention, the water-insoluble metal compound (C) is preferably titanium dioxide or zirconium dioxide.

In the present invention, the content of the water-insoluble metal compound (C) is preferably 1.5 to 3 parts by weight based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a).

Further, according to the present invention, there is provided a film-formed product formed from the latex composition of the present invention.

Further, the present invention provides a method for producing a dip-molded article, which comprises the step of dip-molding the latex composition of the present invention.

Effects of the invention

The present invention can provide a latex composition capable of forming a film molded article such as a dip molded article which can suppress the occurrence of immediate hypersensitivity (type I) and delayed hypersensitivity (type IV), has high tensile strength, has high stress holding ratio, and can suppress the occurrence of curling winding failure, and a dip molded article and a film molded article obtained using the latex composition.

Detailed Description

The latex composition of the present invention comprises a latex of a carboxyl group-containing conjugated diene rubber (A), a water-soluble metal compound (B), and a water-insoluble metal compound (C) containing a transition metal of group 4 of the periodic Table, wherein the content of the metal compound (C) is 0.5 to 4 parts by weight relative to 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A).

< latex of carboxyl group-containing conjugated diene rubber (A) >

The latex of the carboxyl group-containing conjugated diene rubber (a) used in the present invention is a latex of a copolymer obtained by copolymerizing a monomer mixture containing at least a conjugated diene monomer and an ethylenically unsaturated carboxylic acid monomer, and as the carboxyl group-containing conjugated diene rubber (a), at least 1 selected from the group consisting of a carboxyl group-containing nitrile rubber (a1), a carboxyl group-containing styrene-butadiene rubber (a2), and a carboxyl group-containing conjugated diene rubber (a3) is preferable.

The latex of the carboxyl group-containing nitrile rubber (a1) is a latex of a copolymer obtained by copolymerizing a conjugated diene monomer, an ethylenically unsaturated carboxylic acid monomer and an ethylenically unsaturated nitrile monomer, and may be a latex of a copolymer obtained by copolymerizing another ethylenically unsaturated monomer which can be used as needed and which is copolymerizable with these monomers.

Examples of the conjugated diene monomer include 1, 3-butadiene, isoprene, 2, 3-dimethyl-1, 3-butadiene, 2-ethyl-1, 3-butadiene, 1, 3-pentadiene, chloroprene, and the like. Among these, 1, 3-butadiene and isoprene are preferable, and 1, 3-butadiene is more preferable. These conjugated diene monomers can be used alone or in combination of 2 or more. The content ratio of the conjugated diene monomer unit formed from the conjugated diene monomer in the carboxyl group-containing nitrile rubber (a1) is preferably 56 to 78% by weight, more preferably 56 to 73% by weight, and still more preferably 56 to 68% by weight. When the content of the conjugated diene monomer unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be sufficient, and the hand and elongation can be further excellent.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer having a carboxyl group, and examples thereof include ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; ethylenically unsaturated polycarboxylic acids such as itaconic acid, maleic acid, and fumaric acid; ethylenically unsaturated polycarboxylic acid anhydrides such as maleic anhydride and citric anhydride; and ethylenically unsaturated polycarboxylic acid partial ester monomers such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate. Among these, ethylenically unsaturated monocarboxylic acids are preferred, and methacrylic acid is particularly preferred. These ethylenically unsaturated carboxylic acid monomers can also be used in the form of alkali metal salts or ammonium salts. Further, the ethylenically unsaturated carboxylic acid monomer can be used singly or in combination of 2 or more. The content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed from the ethylenically unsaturated carboxylic acid monomer in the carboxyl group-containing nitrile rubber (a1) is preferably 2 to 5% by weight, more preferably 2 to 4.5% by weight, and still more preferably 2.5 to 4.5% by weight. When the content of the ethylenically unsaturated carboxylic acid monomer unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be made sufficient, and the hand and elongation can be made more excellent.

The ethylenically unsaturated nitrile monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a nitrile group, and examples thereof include acrylonitrile, methacrylonitrile, fumaronitrile, α -chloroacrylonitrile, α -cyanoethylacrylonitrile, and the like. Among them, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable. These ethylenically unsaturated nitrile monomers can be used singly or in combination of 2 or more. The content ratio of the ethylenically unsaturated nitrile monomer unit formed from the ethylenically unsaturated nitrile monomer in the carboxyl group-containing nitrile rubber (a1) is preferably 20 to 40% by weight, more preferably 25 to 40% by weight, and still more preferably 30 to 40% by weight. When the content of the ethylenically unsaturated nitrile monomer unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be made sufficient, and the hand and elongation can be made more excellent.

Examples of the other ethylenically unsaturated monomer copolymerizable with the conjugated diene monomer, the ethylenically unsaturated carboxylic acid monomer and the ethylenically unsaturated nitrile monomer include vinyl aromatic monomers such as styrene, alkylstyrene and vinylnaphthalene; fluoroalkyl vinyl ethers such as fluoroethyl vinyl ether; ethylenically unsaturated amide monomers such as (meth) acrylamide, N-methylol (meth) acrylamide, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N-propoxymethyl (meth) acrylamide; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, dibutyl maleate, dibutyl fumarate, diethyl maleate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, cyanomethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, 2-ethyl-6-cyanohexyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, and mixtures thereof, Ethylenically unsaturated carboxylic acid ester monomers such as dimethylaminoethyl (meth) acrylate; and crosslinkable monomers such as divinylbenzene, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol (meth) acrylate, and the like. These ethylenically unsaturated monomers can be used singly or in combination of 2 or more.

The content ratio of the other monomer unit composed of the other ethylenically unsaturated monomer in the carboxyl group-containing nitrile rubber (a1) is preferably 10% by weight or less, more preferably 5% by weight or less, and still more preferably 3% by weight or less.

The latex of the carboxyl group-containing nitrile rubber (a1) used in the present invention is obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, and preferably a method of copolymerizing by emulsion polymerization. As the emulsion polymerization method, a conventionally known method can be employed.

In emulsion polymerization of a monomer mixture containing the above-mentioned monomers, a polymerization auxiliary material such as a generally used emulsifier, polymerization initiator, molecular weight regulator, or the like can be used. The method of adding these polymerization auxiliary materials is not particularly limited, and any of the initial one-time addition method, the batch addition method, the continuous addition method, and the like may be used.

The emulsifier is not particularly limited, and examples thereof include nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester, and polyoxyethylene sorbitan alkyl ester; anionic emulsifiers such as potassium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate and other alkylbenzenesulfonates, higher alcohol sulfate salts, and alkylsulfosuccinate salts; cationic emulsifiers such as alkyltrimethylammonium chloride, dialkylammonium chloride and benzylammonium chloride; and copolymerizable emulsifiers such as sulfonic acid esters of α, β -unsaturated carboxylic acids, sulfuric acid esters of α, β -unsaturated carboxylic acids, and sulfoalkylaryl ethers. Among them, anionic emulsifiers are preferable, alkylbenzenesulfonates are more preferable, and potassium dodecylbenzenesulfonate and sodium dodecylbenzenesulfonate are particularly preferable. These emulsifiers can be used alone or in combination of 2 or more. The amount of the emulsifier used is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the monomer mixture.

The polymerization initiator is not particularly limited, and examples thereof include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; organic peroxides such as dicumyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,3, 3-tetramethylbutyl hydroperoxide, 2, 5-dimethylhexane-2, 5-dihydroperoxide, di-t-butyl peroxide, di- α -cumene peroxide, acetyl peroxide, isobutyryl peroxide, and benzoyl peroxide; azo compounds such as azobisisobutyronitrile, azobis-2, 4-dimethylvaleronitrile, and methyl azobisisobutyrate. These polymerization initiators can be used alone or in combination of 2 or more. The amount of the polymerization initiator used is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the monomer mixture.

In addition, peroxide initiators can be used as redox polymerization initiators in combination with reducing agents. The reducing agent is not particularly limited, and examples thereof include compounds containing a metal ion in a reduced state, such as ferrous sulfate and cuprous naphthenate; sulfonic acid compounds such as sodium methanesulfonate; amine compounds such as dimethylaniline, and the like. These reducing agents can be used alone or in combination of 2 or more. The amount of the reducing agent used is preferably 3 to 1000 parts by weight based on 100 parts by weight of the peroxide.

The amount of water used in the emulsion polymerization is preferably 80 to 600 parts by weight, and particularly preferably 100 to 200 parts by weight, based on 100 parts by weight of the total monomers used.

Examples of the method of adding the monomer include a method of adding the monomer to be used to a reaction vessel at a time; a method of continuously or intermittently adding the polymer as the polymerization proceeds; any method may be employed, for example, a method in which a part of the monomer is added to react to a specific conversion, and then the remaining monomer is continuously or intermittently added to carry out polymerization. In the case where the monomers are mixed, continuously or intermittently added, the composition of the mixture may be fixed, or may be changed. In addition, the respective monomers may be added to the reaction vessel after being mixed in advance, or may be added to the reaction vessel separately.

Further, if necessary, polymeric auxiliary materials such as chelating agents, dispersants, pH adjusters, deoxidizers, and particle size adjusters can be used, and the type and amount of these polymeric auxiliary materials are not particularly limited.

The polymerization temperature in the emulsion polymerization is not particularly limited, but is usually 3 to 95 ℃ and preferably 5 to 60 ℃. The polymerization time is about 5 to 40 hours.

The monomer mixture is emulsion polymerized as described above, and when a predetermined polymerization conversion rate is reached, the polymerization system is cooled or a polymerization terminator is added to terminate the polymerization reaction. The polymerization conversion at the time of terminating the polymerization reaction is preferably 90% by weight or more, more preferably 93% by weight or more.

The polymerization terminator is not particularly limited, and examples thereof include hydroxylamine, hydroxylamine sulfate, diethylhydroxylamine, hydroxylamine sulfonic acid and alkali metal salts thereof; sodium dimethyldithiocarbamate; a hydroquinone derivative; catechol derivatives, and aromatic hydroxydithiocarboxylic acids such as hydroxydimethylthiobenzoic acid, hydroxydiethyldithiobenzoic acid, and hydroxydibutyldithiocarbonic acid, and alkali metal salts thereof. The amount of the polymerization terminator to be used is preferably 0.05 to 2 parts by weight based on 100 parts by weight of the monomer mixture.

After the termination of the polymerization reaction, unreacted monomers are removed as desired, and the solid content concentration and pH are adjusted, whereby a latex of the carboxyl group-containing nitrile rubber (a1) can be obtained.

The latex of the carboxyl group-containing nitrile rubber (a1) used in the present invention may be appropriately added with an antioxidant, a preservative, an antibacterial agent, a dispersant, and the like, as required.

The number average particle diameter of the latex of the carboxyl group-containing nitrile rubber (a1) used in the present invention is preferably 60 to 300nm, more preferably 80 to 150 nm. The particle diameter can be adjusted to a desired value by adjusting the amount of the emulsifier and the polymerization initiator used, and the like.

The latex of the carboxyl-group-containing styrene-butadiene rubber (a2) used in the present invention is a latex of a copolymer obtained by copolymerizing 1, 3-butadiene as a conjugated diene monomer, an ethylenically unsaturated carboxylic acid monomer, and styrene, and may be a latex of a copolymer obtained by copolymerizing another ethylenically unsaturated monomer which can be copolymerized with these monomers, if necessary.

The content ratio of the butadiene unit composed of 1, 3-butadiene in the carboxyl-group-containing styrene-butadiene rubber (a2) is preferably 56 to 78% by weight, more preferably 56 to 73% by weight, and still more preferably 56 to 68% by weight. When the butadiene unit content is in the above range, the tensile strength of the obtained film molded product such as a dip molded product can be made sufficient, and the hand and elongation can be further improved.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer having a carboxyl group, and for example, the same ethylenically unsaturated carboxylic acid monomer as in the latex of the carboxyl group-containing nitrile rubber (a1) can be used. The content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed from the ethylenically unsaturated carboxylic acid monomer in the carboxyl-group-containing styrene-butadiene rubber (a2) is preferably 2 to 5% by weight, more preferably 2 to 4.5% by weight, and still more preferably 2.5 to 4.5% by weight. When the content of the ethylenically unsaturated carboxylic acid monomer unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be made sufficient, and the hand and elongation can be made more excellent.

The content ratio of the styrene unit composed of styrene in the carboxyl-group-containing styrene-butadiene rubber (a2) is preferably 20 to 40% by weight, more preferably 25 to 40% by weight, and still more preferably 30 to 40% by weight. When the content of the styrene unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be sufficient, and the hand and the elongation can be further excellent.

Examples of the other ethylenically unsaturated monomer copolymerizable with 1, 3-butadiene, the ethylenically unsaturated carboxylic acid monomer and styrene as the conjugated diene monomer include, in addition to the ethylenically unsaturated monomer (except styrene) similar to the latex of the carboxyl group-containing nitrile rubber (a1), conjugated diene monomers other than 1, 3-butadiene, such as isoprene, 2, 3-dimethyl-1, 3-butadiene, 2-ethyl-1, 3-butadiene, 1, 3-pentadiene and chloroprene. The content ratio of the other monomer unit formed from the other ethylenically unsaturated monomer in the carboxyl-group-containing styrene-butadiene rubber (a2) is preferably 10% by weight or less, more preferably 5% by weight or less, and still more preferably 3% by weight or less.

The latex containing the carboxyl-group styrene-butadiene rubber (a2) used in the present invention is obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, preferably by emulsion polymerization. The emulsion polymerization method may be carried out using the same polymerization auxiliary material and the same method as in the case of the carboxyl group-containing nitrile rubber (a 1).

In addition, the latex containing the carboxyl group-containing styrene-butadiene rubber (a2) used in the present invention may be appropriately added with an age resister, an antiseptic, an antibacterial agent, a dispersant, and the like as needed.

The number average particle diameter of the latex containing the carboxyl-group-containing styrene-butadiene rubber (a2) used in the present invention is preferably 60 to 300nm, more preferably 80 to 150 nm. The particle diameter can be adjusted to a desired value by adjusting the amount of the emulsifier and the polymerization initiator used, and the like.

The latex of the carboxyl group-containing conjugated diene rubber (a3) used in the present invention is a latex of a copolymer obtained by copolymerizing a conjugated diene monomer and an ethylenically unsaturated carboxylic acid monomer, and may be a latex of a copolymer obtained by copolymerizing another ethylenically unsaturated monomer which can be copolymerized with the conjugated diene monomer and the ethylenically unsaturated carboxylic acid monomer, if necessary.

The content ratio of the conjugated diene monomer unit formed from the conjugated diene monomer in the carboxyl group-containing conjugated diene rubber (a3) is preferably 80 to 98% by weight, more preferably 90 to 98% by weight, and still more preferably 95 to 97.5% by weight. When the content of the conjugated diene monomer unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be sufficient, and the hand and elongation can be further excellent.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer having a carboxyl group, and for example, the same ethylenically unsaturated carboxylic acid monomer as in the latex of the carboxyl group-containing nitrile rubber (a1) can be used. The content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed from the ethylenically unsaturated carboxylic acid monomer in the carboxyl group-containing conjugated diene rubber (a3) is preferably 2 to 10% by weight, more preferably 2 to 7.5% by weight, and still more preferably 2.5 to 5% by weight. When the content of the ethylenically unsaturated carboxylic acid monomer unit is in the above range, the tensile strength of the obtained film molded article such as a dip molded article can be made sufficient, and the hand and elongation can be made more excellent.

Examples of the conjugated diene monomer include 1, 3-butadiene, isoprene, 2, 3-dimethyl-1, 3-butadiene, 2-ethyl-1, 3-butadiene, 1, 3-pentadiene, chloroprene, and the like, and any of these conjugated diene monomers may be used alone, or 2 or more thereof may be used in combination.

Examples of the other ethylenically unsaturated monomer copolymerizable with the conjugated diene monomer and the ethylenically unsaturated carboxylic acid monomer include the same ethylenically unsaturated monomers as in the latex of the carboxyl group-containing nitrile rubber (a 1). The content ratio of the other monomer unit composed of the other ethylenically unsaturated monomer in the carboxyl group-containing conjugated diene rubber (a3) is preferably 10% by weight or less, more preferably 5% by weight or less, and still more preferably 3% by weight or less.

The latex of the carboxyl group-containing conjugated diene rubber (a3) used in the present invention is obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, and the copolymerization is preferably carried out by emulsion polymerization. The emulsion polymerization method may be carried out using the same polymerization auxiliary material and the same method as in the case of the carboxyl group-containing nitrile rubber (a 1).

The latex of the carboxyl group-containing conjugated diene rubber (a3) used in the present invention may be appropriately added with an antioxidant, a preservative, an antibacterial agent, a dispersant, and the like, as required.

The number average particle diameter of the latex of the carboxyl group-containing conjugated diene rubber (a3) used in the present invention is preferably 60 to 300nm, more preferably 80 to 150 nm. The particle diameter can be adjusted to a desired value by adjusting the amount of the emulsifier and the polymerization initiator used, and the like.

< Water-soluble Metal Compound (B) >

The latex composition of the present invention contains a water-soluble metal compound (B) in addition to the latex of the carboxyl group-containing conjugated diene rubber (a). In the latex composition of the present invention, the water-soluble metal compound (B) functions as a crosslinking agent.

According to the present invention, the water-soluble metal compound (B) is used as a crosslinking agent instead of sulfur which is generally used as a crosslinking agent, and a sulfur-containing vulcanization accelerator is not required at the time of crosslinking, so that not only immediate allergy (I type) but also delayed allergy (IV type) due to sulfur and a sulfur-containing vulcanization accelerator can be effectively suppressed.

The water-soluble metal compound (B) is not particularly limited as long as it contains a metal and exhibits solubility in water, and examples thereof include a sodium compound, a potassium compound, a lithium compound, a calcium compound, a magnesium compound, an aluminum compound, and a cobalt compound, and among these, a water-soluble metal compound containing a metal having a valence of 3 or more, such as an aluminum compound and a cobalt compound, is preferable, a water-soluble metal compound containing a metal having a valence of 3 or more, and an aluminum compound is more preferable, in terms of enabling the carboxyl-containing conjugated diene rubber (a) contained in the latex to be more favorably crosslinked.

The aluminum compound is not particularly limited, and examples thereof include aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum ammonium sulfate, aluminum bromide, aluminum fluoride, potassium ammonium sulfate, aluminum isopropoxide, sodium aluminate, potassium aluminate, and sodium aluminum sulfite. These aluminum compounds can be used alone or in combination of 2 or more. Among these, sodium aluminate is preferable in terms of the effect of the present invention being more remarkable.

The content of the water-soluble metal compound (B) in the latex composition of the present invention is 0.1 to 1.5 parts by weight, preferably 0.1 to 1.25 parts by weight, and more preferably 0.1 to 1.0 part by weight, based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a) contained in the latex. When the content of the water-soluble metal compound (B) is within the above range, the latex composition can be made excellent in stability, and therefore, the latex composition can be effectively inhibited from generating aggregates and can be sufficiently crosslinked, and the film molded article such as a dip molded article obtained can be made further excellent in tensile strength and stress holding rate.

< Water-insoluble Metal Compound (C) containing a transition Metal of group 4 of the periodic Table of the elements >

The slurry composition of the present invention contains a water-insoluble metal compound (C) containing a transition metal of group 4 of the periodic table in addition to the latex of the carboxyl group-containing conjugated diene rubber (a) and the water-soluble metal compound (B), and particularly contains the water-insoluble metal compound (C) containing the transition metal of group 4 of the periodic table in a proportion of 0.5 to 4 parts by weight relative to 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a) contained in the latex.

In the present invention, by containing the water-insoluble metal compound (C) containing the group 4 transition metal of the periodic table (hereinafter, appropriately referred to as "group 4 metal compound (C)") in the latex composition at the above content ratio, when a dip-molded article is obtained using a dip-molding die, the adhesion strength between the formed dip-molded layer and the dip-molding die can be reduced, and thereby the curling (sleeve forming) properties can be improved, and as a result, the occurrence of a curling winding failure can be effectively suppressed.

In particular, the present inventors have conducted intensive studies and as a result, found that, when the above-mentioned water-soluble metal compound (B) is used as a crosslinking agent, although the occurrence of delayed allergy (type IV) due to sulfur or a sulfur-containing vulcanization accelerator can be effectively suppressed in addition to immediate allergy (type I), the crimping property (sleeve forming) is insufficient and a crimping winding failure occurs, and on the contrary, when the group 4 metal compound (C) is contained in the above-mentioned content ratio, the adhesion strength between the dip-formed layer formed by dip forming and the dip-forming die (for example, the peel strength can be preferably 10N or less, more preferably 8N or less) can be reduced and the occurrence of a crimping winding failure can be effectively suppressed.

The group 4 metal compound (C) is not particularly limited as long as it is a compound that contains a group 4 transition metal of the periodic table and does not exhibit solubility in water (i.e., a compound that is insoluble in water), and titanium dioxide (TiO) may be mentioned₂) Zirconium dioxide (ZrO)₂) Hafnium oxide (HfO)₂) Oxides of transition metals of group 4; hafnium tetrabromide (HfBr)₄) And bromides of group 4 transition metals. Among these, from the viewpoint of high effect of suppressing the occurrence of the curling failure, an oxide of a group 4 transition metal is preferable, and titanium dioxide (TiO) is more preferable₂) Zirconium dioxide (ZrO)₂)。

The content of the group 4 metal compound (C) in the latex composition of the present invention is 0.5 to 4 parts by weight, preferably 1 to 3.5 parts by weight, and more preferably 1.5 to 3.0 parts by weight, based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a) contained in the latex. When the content ratio of the group 4 metal compound (C) is too small or too large, when a film molded body such as a dip molded body is obtained using a dip molding die, the adhesion strength between the dip molded layer formed by dip molding and the dip molding die becomes high, and the effect of suppressing the occurrence of the curling failure cannot be obtained.

The content ratio of the water-soluble metal compound (B) and the group 4 metal compound (C) in the latex composition of the present invention is preferably 1: 2.6 to 1: 15, more preferably 1: 2.8 to 1: 10, and still more preferably 1: 3 to 1: 5 in terms of the weight ratio of the water-soluble metal compound (B) to the group 4 metal compound (C).

In addition to the latex of the carboxyl group-containing conjugated diene rubber (a), the water-soluble metal compound (B) and the group 4 metal compound (C), the latex composition of the present invention may further contain at least 1 alcoholic hydroxyl compound (D) selected from the group consisting of a saccharide (D1), a sugar alcohol (D2), a hydroxy acid (D3) and a hydroxy acid salt (D4). By further blending the alcoholic hydroxyl compound (D), the stability of the latex composition can be further improved.

The saccharide (d1) is not particularly limited as long as it is a monosaccharide or a polysaccharide in which 2 or more monosaccharides are glycosidically bonded, and examples thereof include monosaccharides such as erythrose, threose, ribose, lyxose, xylose, arabinose, allose, talose, gulose, altrose, galactose, idose, erythrulose, xylulose, ribulose, psicose, fructose, sorbose, and tagatose; disaccharides such as trehalose, maltose, isomaltose, cellobiose, gentiobiose, melibiose, lactose, sucrose, and palatinose; trisaccharides such as maltotriose, isomaltotriose, panose, cellotriose, mannotriose, solanotriose (solatriose), melezitose, psyllium sugar, gentiotriose, umbelliferose, lactulose, raffinose, and the like; oligosaccharides such as maltotetraose and isomaltotetraose; tetrasaccharides such as stachyose, cellotetraose, garlic sugar, lichenose (lichenose); pentasaccharides such as maltopentasaccharide and isomaltopentaose; hexasaccharides such as maltohexaose and isomaltose. These may be used alone in 1 kind, or may also be used in combination of 2 or more.

The sugar alcohol (d2) is not particularly limited as long as it is a monosaccharide or polysaccharide, and examples thereof include glycerol; erythritol, D-threitol, L-threitol and other tetritols; pentitol such as D-arabitol, L-arabitol, xylitol, ribitol, pentaerythritol, etc.; pentaerythritol; hexitols such as sorbitol, D-iditol, galactitol, D-glucitol, and mannitol; heptitol such as heptatol and mannoheptitol; and octitol such as D-erythritol-D-galactose-octitol. These may be used alone in 1 kind, or may also be used in combination of 2 or more. Among these, hexitol which is a sugar alcohol having 6 carbon atoms is preferable, and sorbitol is more preferable.

The hydroxy acid (d3) is not particularly limited as long as it is a carboxylic acid having a hydroxyl group, and examples thereof include aliphatic hydroxy acids such as glycolic acid, lactic acid, tartronic acid, glyceric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, γ -hydroxybutyric acid, malic acid, 3-methylmalic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucine, mevalonic acid, pantoic acid, ricinoleic acid, cerebral hydroxyoleic acid, quinic acid, shikimic acid, and serine; salicylic acid, creosolic acid (homosalicylic acid, hydroxy (methyl) benzoic acid), vanillic acid, syringic acid, hydroxypropionic acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, hydroxynonanoic acid, hydroxydecanoic acid, hydroxyundecanoic acid, hydroxydodecanoic acid, hydroxytridecanoic acid, hydroxytetradecanoic acid, hydroxypentadecanoic acid, hydroxyheptadecanoic acid, hydroxyoctadecanoic acid, hydroxynonadecanoic acid, monohydroxybenzoic acid derivatives such as hydroxyeicosanoic acid and ricinoleic acid, dihydroxybenzoic acid derivatives such as pyrocatechol, resorcylic acid, protocatechuic acid, gentisic acid and thioctic acid, trihydroxybenzoic acid derivatives such as gallic acid, phenylacetic acid derivatives such as mandelic acid, benzoic acid and atrolactic acid, aromatic hydroxy acids such as cinnamic acid/hydrocinnamic acid derivatives such as melilotic acid, phlorogluconic acid, coumaric acid, umbellic acid, caffeic acid, ferulic acid and sinapic acid, and the like. These may be used alone in 1 kind, or may also be used in combination of 2 or more. Among these, aliphatic hydroxy acids are preferred, aliphatic α -hydroxy acids are more preferred, glycolic acid, lactic acid, tartaric acid, glyceric acid, malic acid, tartaric acid, citric acid are further preferred, and glycolic acid is particularly preferred.

The hydroxy acid salt (d4) is not particularly limited as long as it is a salt of a hydroxy acid, and specific examples of the hydroxy acid (d3) include metal salts of a hydroxy acid, and examples thereof include salts of alkali metals such as sodium and potassium; salts of alkaline earth metals such as calcium and magnesium. As the hydroxy acid salt (d4), 1 kind may be used alone, or 2 or more kinds may be used in combination. As the hydroxy acid salt (d4), an alkali metal salt of a hydroxy acid is preferred, and a sodium salt of a hydroxy acid is preferred. The hydroxy acid constituting the hydroxy acid salt (d4) is preferably an aliphatic hydroxy acid, more preferably an aliphatic α -hydroxy acid, further preferably glycolic acid, lactic acid, tartronic acid, glyceric acid, malic acid, tartaric acid, or citric acid, and particularly preferably glycolic acid. That is, sodium glycolate is particularly preferable as the hydroxy acid salt (d 4).

The content of the alcoholic hydroxyl compound (D) in the latex composition of the invention is preferably in the range of 1: 0.1 to 1: 50, more preferably in the range of 1: 0.2 to 1: 45, and still more preferably in the range of 1: 0.3 to 1: 30, in terms of the weight ratio of the water-soluble metal compound (B) to the alcoholic hydroxyl compound (D) relative to the water-soluble metal compound (B). By containing the alcoholic hydroxyl compound (D) in the above-mentioned ratio, the stability of the latex composition can be further suitably improved.

The content of the alcoholic hydroxyl group-containing compound (D) in the latex composition of the present invention is preferably 0.03 to 15 parts by weight, and more preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (a) contained in the latex.

The latex composition of the present invention can be obtained by, for example, adding a water-soluble metal compound (B), a group 4 metal compound (C), and if necessary, an alcoholic hydroxyl group-containing compound (D) to a latex of a carboxyl group-containing conjugated diene rubber (a). The method of adding the water-soluble metal compound (B) and the group 4 metal compound (C) to the latex of the carboxyl group-containing conjugated diene rubber (a) is not particularly limited, and from the viewpoint of enabling the water-soluble metal compound (B) and the group 4 metal compound (C) to be well dispersed in the resulting latex composition, it is preferable to add the water-soluble metal compound (B) in the form of an aqueous solution or an alcoholic solution by dissolving it in water or alcohol, and to add the group 4 metal compound (C) in the form of an aqueous dispersion or an alcoholic dispersion by dispersing it in water or alcohol. Further, in the case of using the alcoholic hydroxyl compound (D), from the viewpoint of further appropriately dispersing the water-soluble metal compound (B) in the obtained latex composition, it is preferable to dissolve the water-soluble metal compound (B) and the alcoholic hydroxyl compound (D) in water or alcohol and add them in the state of an aqueous solution or an alcoholic solution.

The latex composition of the present invention may further contain, in addition to the latex of the carboxyl group-containing conjugated diene rubber (a), the water-soluble metal compound (B), the group 4 metal compound (C), and the alcoholic hydroxyl group-containing compound (D) used as needed, a filler, a pH adjuster, a thickener, an antioxidant, a dispersant, a pigment, a softener, and the like as desired.

The solid content concentration of the latex composition of the present invention is preferably 10 to 40% by weight, and more preferably 15 to 35% by weight. That is, the proportion of water in the latex composition of the present invention is preferably 60 to 90% by weight, and more preferably 65 to 85% by weight. In addition, the pH of the latex composition of the present invention is preferably 8.0 to 12, and more preferably 8.5 to 11.

< molded film >

The film-shaped product of the present invention is a film-shaped product formed from the latex composition of the present invention. The film thickness of the film-formed article of the present invention is preferably 0.03 to 0.50mm, more preferably 0.05 to 0.40mm, and particularly preferably 0.08 to 0.30 mm.

The film molded product of the present invention is not particularly limited, and is preferably a dip molded product obtained by dip molding the latex composition of the present invention. The dip forming method comprises the following steps: the dip forming die is dipped in the latex composition to deposit the composition on the surface of the dip forming die, and then the dip forming die is lifted up from the composition, and thereafter, the composition deposited on the surface of the dip forming die is dried. In addition, the dip forming die before dipping in the latex composition may be preheated. The coagulant may be used as needed before the dip mold is dipped in the latex composition or after the dip mold is pulled out of the latex composition.

Specific examples of the method of using the coagulant include the following methods: a method in which a dip-molded article before dipping in the latex composition is dipped in a solution of a coagulant to adhere the coagulant to a dip-molding die (anodic adhesion dipping method); the method of dipping the dip forming mold deposited with the latex composition in the coagulant solution (Teague adhesion dipping method) is preferably an anodic adhesion dipping method in view of obtaining a dip formed body with a small thickness variation.

Examples of the coagulant include halogenated metals such as barium chloride, calcium chloride, magnesium chloride, zinc chloride, and aluminum chloride; nitrates such as barium nitrate, calcium nitrate, and zinc nitrate; acetates such as barium acetate, calcium acetate, and zinc acetate; sulfates such as calcium sulfate, magnesium sulfate, and aluminum sulfate. Among them, calcium chloride and calcium nitrate are preferable.

The coagulant is usually used as a solution of water, alcohol, or a mixture of these. The concentration of the coagulant is usually 5 to 50% by weight, preferably 10 to 35% by weight.

In addition, when the cuff portion needs to be curled (sleeve curling) such as when the dip-molded article is a glove, the dip-molded layer formed by drying is curled to form a curled portion (sleeve curling). The dip-molded article of the present invention is formed using the latex composition of the present invention, and therefore, the adhesion strength between the dip-molded layer formed by dip molding and the dip-molding die can be reduced, and the occurrence of a curling and winding failure during curling can be effectively suppressed. Therefore, according to the present invention, a dip-molded article having a curled portion can be obtained appropriately.

In addition, the hemming process is as follows: in the process of releasing the dip-molded layer from the dip-molding die, a part of the sleeve portion of the dip-molded layer, which is a grip portion for releasing from the die, is peeled from the dip-molding die, and the peeled portion of the sleeve portion of the dip-molded layer is peeled off so that the width of the sleeve portion is preferably 10 to 50mm, more preferably 20 to 30 mm. In addition, when the obtained impregnated molded article is used for gloves or the like by performing such a hemming process, it is possible to make it difficult to break and easy to wear the article when wearing the glove.

Before the hemming process, the obtained dip-molded layer may be dipped in water, preferably warm water at 30 to 70 ℃ for about 1 to 60 minutes to remove water-soluble impurities (e.g., excess emulsifier, coagulant, etc.). After the removal of the water-soluble impurities, the dip-molded layer subjected to the removal of the water-soluble impurities is preferably dried before the hemming process. The drying conditions in this case are not particularly limited, but are preferably as follows: at 20 to 100 ℃, more preferably 30 to 80 ℃, preferably 1 to 20 minutes, more preferably 1 to 10 minutes.

In addition, the obtained dip-molded layer is usually subjected to a heat treatment for crosslinking after the hemming process. The crosslinking of the dip-formed layer can generally be carried out as follows: the heating treatment is preferably carried out at a temperature of 80 to 150 ℃ for 10 to 130 minutes. As a heating method, an external heating method using infrared rays or hot air, or an internal heating method using high-frequency waves can be used. Among them, external heating using hot air is preferable.

Then, the crosslinked dip-molded layer is released from the dip-molding die, whereby a dip-molded article as a film-shaped film-molded article can be obtained. As the mold release method, a method of releasing the mold from the molding die by hand or a method of releasing the mold by pressure of water pressure or compressed air can be used. After the mold release, the mold may be further subjected to a heating treatment at 60 to 120 ℃ for 10 to 120 minutes.

The film molded article of the present invention comprising the dip molded article of the present invention is obtained by using the above-described latex composition of the present invention, and therefore, can suppress the occurrence of immediate hypersensitivity (type I) and delayed hypersensitivity (type IV), has high tensile strength, has a high stress retention rate, and can suppress the occurrence of curling and winding failure, and therefore, can be preferably used for applications such as use in contact with a human body and where a curled portion (curled sleeve portion) is desired, and particularly, glove applications, particularly, surgical gloves, are preferable. Alternatively, the dip molded body of the present invention can be used for medical supplies such as a nipple for a baby bottle, a dropper, a tube, a water pillow, an air bag, a catheter, and a condom, in addition to gloves; balloons, dolls, balls, and other toys; industrial products such as pressure-forming bags and gas storage bags; finger cot, etc.