JPWO2019003743A1 - Latex composition - Google Patents

Abstract

A latex composition containing a latex of a carboxy-modified conjugated diene polymer, a palladium compound, and an oxide of a metal other than palladium, wherein 100 parts by weight of the carboxy-modified conjugated diene polymer of the palladium compound A latex composition having a content of 0.01 to 2.00 parts by weight in terms of palladium metal is provided.

Description

  The present invention relates to a latex composition, more specifically, it is excellent in stability as a latex composition, and can suppress the occurrence of symptoms of delayed type allergy (Type IV) in addition to immediate type allergy (Type I), Also, the present invention relates to a latex composition capable of giving a film molded article such as a dip molded article having a high tensile strength and a large elongation, and a film molded article and an adhesive layer-forming substrate using the latex composition.

  It is conventionally known that a latex composition containing a latex of natural rubber is dip-molded to obtain a dip-molded product which is used in contact with a human body such as a nipple, a balloon, gloves, a balloon, and a sack. However, since the latex of natural rubber contains a protein that causes the symptoms of immediate allergy (Type I) in the human body, it may have a problem as a dip-molded product that comes into direct contact with a living mucous membrane or an organ. Therefore, it has been studied to use synthetic rubber latex instead of natural rubber latex.

  For example, Patent Document 1 discloses, as a dip-molding composition, a latex composition in which a latex of synthetic polyisoprene which is a synthetic rubber is mixed with zinc oxide, sulfur and a vulcanization accelerator. However, the technique of Patent Document 1 can prevent the occurrence of an immediate allergy (Type I) due to a protein derived from natural rubber, while the vulcanization accelerator contained in the dip-molded product when the dip-molded product is formed. As a result, when touching a human body, an allergic symptom of delayed type allergy (Type IV) may occur.

International Publication No. 2014/129547

  The present invention has been made in view of such circumstances, and is excellent in stability as a latex composition, and suppresses the occurrence of symptoms of delayed type allergy (Type IV) in addition to immediate type allergy (Type I). A latex composition capable of giving a film-formed product such as a dip-formed product having a high tensile strength and a large elongation, and a film-formed product and an adhesive layer-forming substrate using the latex composition Regarding

  The present inventors, as a result of intensive studies to achieve the above objects, a latex of a carboxy-modified conjugated diene polymer, a predetermined amount of a palladium compound, by blending an oxide of a metal other than palladium It was found that the above object can be achieved by the latex composition described above, and the present invention has been completed.

  That is, according to the present invention, there is provided a latex composition containing a latex of a carboxy-modified conjugated diene-based polymer, a palladium compound, and an oxide of a metal other than palladium, wherein the carboxy-modified conjugated diene-based polymer 100. Provided is a latex composition in which the content ratio of the palladium compound with respect to parts by weight is 0.01 to 2.00 parts by weight in terms of palladium element.

In the latex composition of the present invention, the total content of the sulfur-based vulcanizing agent and the sulfur-containing vulcanization accelerator is preferably 0.5 parts by weight or less based on 100 parts by weight of the carboxy-modified conjugated diene polymer. ..
In the latex composition of the present invention, the carboxy-modified conjugated diene-based polymer is preferably carboxy-modified synthetic polyisoprene.
In the latex composition of the present invention, the modification rate of the carboxy-modified conjugated diene polymer is preferably 0.01 to 10%.
In the latex composition of the present invention, the content ratio of the oxide of the metal other than palladium is preferably 0.01 to 30 parts by weight with respect to 100 parts by weight of the carboxy-modified conjugated diene polymer.

Further, according to the present invention, there is provided a film molded body comprising the above latex composition.
Further, according to the present invention, there is provided an adhesive layer-forming base material in which the adhesive layer made of the above latex composition is formed on the surface of the base material.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in stability as a latex composition, it is possible to suppress the occurrence of symptoms of delayed type allergy (Type IV) in addition to immediate type allergy (Type I), and high tensile strength, It is possible to provide a latex composition capable of giving a film molded product such as a dip molded product having a large elongation. Further, according to the present invention, it is also possible to provide a film molded body and an adhesive layer-forming substrate using such a latex composition.

  The latex composition of the present invention contains a latex of a carboxy-modified conjugated diene-based polymer, a palladium compound, and an oxide of a metal other than palladium, and the palladium is based on 100 parts by weight of the carboxy-modified conjugated diene-based polymer. The latex composition has a compound content of 0.01 to 2.00 parts by weight in terms of palladium element.

  The latex of a carboxy-modified conjugated diene polymer used in the present invention is, for example, a latex of a carboxy-modified conjugated diene polymer obtained by modifying a conjugated diene polymer with a compound having a carboxyl group.

Conjugated diene-based polymer The conjugated diene-based polymer is not particularly limited, and examples thereof include synthetic polyisoprene, styrene-isoprene-styrene block copolymer (SIS), nitrile group-containing conjugated diene-based copolymer, butadiene polymer. , Styrene-butadiene copolymer and the like. Among these, those containing an isoprene unit such as synthetic polyisoprene and SIS are preferable, and synthetic polyisoprene is particularly preferable, from the viewpoint that the effect of the present invention is great.

  When synthetic polyisoprene is used as the conjugated diene-based polymer, the synthetic polyisoprene may be a homopolymer of isoprene or may be a copolymer of isoprene and another ethylenically unsaturated monomer copolymerizable with isoprene. It may be polymerized. The content of isoprene units in the synthetic polyisoprene is preferably 70% by weight or more, based on all the monomer units, because it is easy to obtain a film molded article such as a dip molded article which is flexible and has excellent tensile strength. The content is more preferably 90% by weight or more, further preferably 95% by weight or more, and particularly preferably 100% by weight (isoprene homopolymer).

  Other ethylenically unsaturated monomers copolymerizable with isoprene include, for example, conjugated diene monomers other than isoprene such as butadiene, chloroprene, and 1,3-pentadiene; acrylonitrile, methacrylonitrile, fumaronitrile, α- Ethylenically unsaturated nitrile monomers such as chloroacrylonitrile; vinyl aromatic monomers such as styrene and alkylstyrene; methyl (meth) acrylate (means "methyl acrylate and / or methyl methacrylate"; , Ethyl (meth) acrylate, etc.), ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, etc., ethylenically unsaturated carboxylic acid ester monomers; Is mentioned. These other ethylenically unsaturated monomers copolymerizable with isoprene may be used alone or in combination of two or more.

Synthetic polyisoprene can be prepared in an inert polymerization solvent using a conventionally known method, for example, a Ziegler-based polymerization catalyst composed of trialkylaluminum-titanium tetrachloride or an alkyllithium polymerization catalyst such as n-butyllithium or sec-butyllithium. , Isoprene, and other copolymerizable ethylenically unsaturated monomer used as necessary can be obtained by solution polymerization. The polymer solution of synthetic polyisoprene obtained by solution polymerization may be used as it is for the production of synthetic polyisoprene latex, but after taking out solid synthetic polyisoprene from the polymer solution, it is dissolved in an organic solvent. It can also be used for the production of synthetic polyisoprene latex. In the present invention, it is preferable to obtain the synthetic polyisoprene in the form of latex, that is, the synthetic polyisoprene latex from the viewpoint that the production of the latex of the carboxy-modified conjugated diene polymer is easy.
Further, when a polymer solution of synthetic polyisoprene is obtained by the method described above, impurities such as the residue of the polymerization catalyst remaining in the polymer solution may be removed. Further, an anti-aging agent described below may be added to the solution during or after the polymerization. Further, commercially available solid synthetic polyisoprene can also be used.

  There are four types of isoprene units in the synthetic polyisoprene, which are a cis bond unit, a trans bond unit, a 1,2-vinyl bond unit, and a 3,4-vinyl bond unit, depending on the bonding state of the isoprene. From the viewpoint of further increasing the tensile strength of the resulting membrane-formed product such as a dip-formed product, the content ratio of the cis bond unit in the isoprene unit contained in the synthetic polyisoprene is preferably 70% by weight based on all isoprene units. As described above, the content is more preferably 90% by weight or more, and further preferably 95% by weight or more.

  The weight average molecular weight of the synthetic polyisoprene is preferably 10,000 to 5,000,000, more preferably 500,000 to 5,000,000, and further preferably, in terms of standard polystyrene by gel permeation chromatography analysis. Is 800,000 to 3,000,000. By setting the weight average molecular weight of the synthetic polyisoprene within the above range, the synthetic polyisoprene latex can be easily produced, and at the same time, the tensile strength of the obtained membrane-formed product such as a dip-formed product can be further increased.

  Moreover, the polymer Mooney viscosity (ML1 + 4, 100 ° C.) of the synthetic polyisoprene is preferably 50 to 80, more preferably 60 to 80, and further preferably 70 to 80.

  As a method for obtaining a synthetic polyisoprene latex containing such a synthetic isoprene, for example, (1) a solution or fine suspension of a synthetic polyisoprene dissolved or finely dispersed in an organic solvent is used as an anionic surfactant. A method for producing a synthetic polyisoprene latex by emulsifying in water in the presence of an agent and removing an organic solvent if necessary, (2) isoprene alone, or isoprene and an ethylenically unsaturated monomer copolymerizable therewith And a method of directly producing a synthetic polyisoprene latex by emulsion polymerization or suspension polymerization in the presence of an anionic surfactant, but the ratio of cis bond units in the isoprene unit is The production method of (1) above is preferable because a high synthetic polyisoprene can be used, and a film molded product such as a dip molded product having excellent mechanical properties such as tensile strength can be easily obtained. As described above, in the present invention, it is preferable to obtain the synthetic polyisoprene in the form of latex, that is, the synthetic polyisoprene latex, from the viewpoint that the production of the latex of the carboxy-modified conjugated diene polymer is easy. ..

  Examples of the organic solvent used in the above production method (1) include aromatic hydrocarbon solvents such as benzene, toluene and xylene; alicyclic hydrocarbon solvents such as cyclopentane, cyclopentene, cyclohexane and cyclohexene; pentane and hexane. Aliphatic hydrocarbon solvents such as heptane; halogenated hydrocarbon solvents such as methylene chloride, chloroform and ethylene dichloride; and the like. Of these, alicyclic hydrocarbon solvents are preferable, and cyclohexane is particularly preferable.

  The amount of the organic solvent used is preferably 2,000 parts by weight or less, more preferably 20 to 1,500 parts by weight, and further preferably 500 to 1500 parts by weight, based on 100 parts by weight of the synthetic polyisoprene.

  Examples of the anionic surfactant used in the production method (1) include fatty acid salts such as sodium laurate, potassium myristate, sodium palmitate, potassium oleate, sodium linolenate, and sodium rosinate; dodecylbenzenesulfone. Alkylbenzene sulfonates such as sodium acidate, potassium dodecylbenzenesulfonate, sodium decylbenzenesulfonate, potassium decylbenzenesulfonate, sodium cetylbenzenesulfonate, potassium cetylbenzenesulfonate; sodium di (2-ethylhexyl) sulfosuccinate, di (2-Ethylhexyl) alkyl sulfosuccinates such as potassium sulfosuccinate and sodium dioctyl sulfosuccinate; alkyl sulfate ester salts such as sodium lauryl sulfate and potassium lauryl sulfate; sodium polyoxyethylene lauryl ether sulfate, potassium polyoxyethylene lauryl ether sulfate, etc. Polyoxyethylene alkyl ether sulfuric acid ester salt of; monoalkyl phosphates such as sodium lauryl phosphate and potassium lauryl phosphate; and the like.

  Among these anionic surfactants, fatty acid salts, alkylbenzene sulfonates, alkylsulfosuccinates, alkyl sulfate ester salts and polyoxyethylene alkyl ether sulfate ester salts are preferable, and fatty acid salts and alkylbenzene sulfonate salts are particularly preferable.

  In addition, it is possible to more efficiently remove a small amount of a polymerization catalyst derived from synthetic polyisoprene (in particular, aluminum and titanium), and it is possible to suppress the generation of aggregates when a latex composition is produced. It is preferable to use a fatty acid salt in combination with at least one selected from the group consisting of a sulfonate, an alkylsulfosuccinate, an alkyl sulfate ester salt, and a polyoxyethylene alkyl ether sulfate ester salt. It is particularly preferred to use a fatty acid salt in combination. Here, the fatty acid salt is preferably sodium rosinate and potassium rosinate, and the alkylbenzene sulfonate is preferably sodium dodecylbenzenesulfonate and potassium dodecylbenzenesulfonate. These surfactants may be used alone or in combination of two or more.

  As described above, the fatty acid salt is used in combination with at least one selected from the group consisting of alkyl benzene sulfonate, alkyl sulfosuccinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt. Thus, the obtained latex contains at least one selected from the group consisting of alkylbenzene sulfonate, alkylsulfosuccinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt, and a fatty acid salt. ..

  Further, in the production method (1), a surfactant other than the anionic surfactant may be used in combination, and as the surfactant other than the anionic surfactant, α, β-insoluble Examples thereof include copolymerizable surfactants such as sulfoesters of saturated carboxylic acids, sulfate esters of α, β-unsaturated carboxylic acids, and sulfoalkylaryl ethers.

  Furthermore, polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl, as long as it does not inhibit the coagulation by the coagulant used when forming a film by dip molding or the like. You may use together nonionic surfactants, such as ester.

  The amount of the anionic surfactant used in the above production method (1) is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of the synthetic polyisoprene. is there. When two or more kinds of surfactants are used, the total amount of these used is preferably within the above range. That is, for example, when a fatty acid salt is used in combination with at least one selected from the group consisting of alkylbenzene sulfonate, alkylsulfosuccinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt, It is preferable that the total amount used is within the above range. If the amount of the anionic surfactant used is too small, a large amount of aggregates may occur during emulsification. On the contrary, if it is too large, foaming tends to occur, resulting in pinholes in film-formed products such as dip-formed products. May occur.

  When a fatty acid salt is used in combination with at least one selected from the group consisting of alkylbenzene sulfonate, alkylsulfosuccinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt as an anionic surfactant. In addition, the ratio of these used is "fatty acid salt": "alkylbenzene sulfonate, alkyl sulfosuccinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt at least one kind of surface active agent selected from The weight ratio of "total amount of agents" is preferably in the range of 1: 1 to 10: 1, more preferably in the range of 1: 1 to 7: 1. If the proportion of at least one surfactant selected from the group consisting of alkyl benzene sulfonate, alkyl sulfosuccinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt is too high, the synthetic polyisoprene is not easily handled. There is a possibility that foaming will become violent, which necessitates an operation such as standing for a long time and addition of an antifoaming agent, which may lead to deterioration in workability and an increase in cost.

  The amount of water used in the production method (1) is preferably 10 to 1,000 parts by weight, more preferably 30 to 500 parts by weight, and most preferably 100 parts by weight of the organic solvent solution of synthetic polyisoprene. Is 50 to 100 parts by weight. Examples of the type of water used include hard water, soft water, ion-exchanged water, distilled water, zeolite water and the like, and soft water, ion-exchanged water and distilled water are preferable.

  A device for emulsifying a solution or fine suspension of a synthetic polyisoprene dissolved or finely dispersed in an organic solvent in water in the presence of an anionic surfactant is generally one that is commercially available as an emulsifier or a disperser. It can be used without particular limitation. The method of adding the anionic surfactant to the solution or fine suspension of the synthetic polyisoprene is not particularly limited and may be previously added to either or both of the solution or the fine suspension of water or the synthetic polyisoprene. It may be added, may be added to the emulsion during the emulsification operation, may be added all at once, or may be added in portions.

  Examples of the emulsifying device include a batch type emulsifier such as a trade name “homogenizer” (manufactured by IKA), a trade name “Polytron” (manufactured by Kinematica), and a trade name “TK Auto Homo Mixer” (manufactured by Tokushu Kika Kogyo). Machine: Product name "TK Pipeline Homo Mixer" (made by Tokushu Kika Kogyo Co., Ltd.), Product name "Colloid Mill" (made by Shinko Pantec Co., Ltd.), Product name "Slasher" (made by Nippon Coke Industry Co., Ltd.), Product name " "Trigonal wet milling machine" (Mitsui Miike Kakoki Co., Ltd.), trade name "Cavitron" (Eurotec Co., Ltd.), trade name "Milder" (Pacific Machine Co., Ltd.), trade name "Fine Flow Mill" (Pacific Kiko Co., Ltd.) High pressure emulsifiers such as product name "Microfluidizer" (manufactured by Mizuho Industry Co., Ltd.), product name "Nanomizer" (manufactured by Nanomizer Co., Ltd.), product name "APV Gaulin" (manufactured by Gaurin Co.) Membrane emulsifiers such as trade name "Membrane emulsifier" (made by Refrigeration Industry Co., Ltd.); Vibratory emulsifiers such as trade name "Vibro Mixer" (made by Refrigeration Industry Co., Ltd.); Trade name "Ultrasonic homogenizer" (Branson Ultrasonic wave emulsifying machine; etc .; and the like. The conditions of the emulsification operation by the emulsification device are not particularly limited, and the treatment temperature, the treatment time, etc. may be appropriately selected so that the desired dispersion state is obtained.

In the production method (1), it is desirable to remove the organic solvent from the emulsion obtained through the emulsification operation.
As a method of removing the organic solvent from the emulsion, a method capable of adjusting the content of the organic solvent (preferably an alicyclic hydrocarbon solvent) in the obtained synthetic polyisoprene latex to 500 ppm by weight or less is preferable, For example, vacuum distillation, atmospheric distillation, steam distillation, centrifugal separation and the like can be used.

  Further, after removing the organic solvent, if necessary, in order to increase the solid content concentration of the synthetic polyisoprene latex, vacuum distillation, atmospheric distillation, centrifugation, may be subjected to concentration operation by a method such as membrane concentration, In particular, it is preferable to perform centrifugation from the viewpoint that the solid content concentration of the synthetic polyisoprene latex can be increased and the residual amount of the surfactant in the synthetic polyisoprene latex can be reduced.

  Centrifugation is carried out, for example, by using a continuous centrifuge, the centrifugal force is preferably 100 to 10,000 G, the solid content concentration of the synthetic polyisoprene latex before centrifugation is preferably 2 to 15% by weight, and the centrifugal separation is performed. It is preferable that the flow rate sent to the machine is 500 to 1700 Kg / hr, and the back pressure (gauge pressure) of the centrifuge is preferably 0.03 to 1.6 MPa. A synthetic polyisoprene latex can be obtained as a liquid. And thereby, the residual amount of the surfactant in the synthetic polyisoprene latex can be reduced.

  The solid content concentration of the synthetic polyisoprene latex is preferably 30 to 70% by weight, more preferably 40 to 70% by weight. When the solid content concentration is too low, the solid content concentration of the latex composition of the present invention becomes low, and as a result, the film molded article such as a dip molded article obtained has a small thickness and is easily broken. On the other hand, if the solid content concentration is too high, the viscosity of the synthetic polyisoprene latex becomes high, which may make it difficult to transfer the synthetic polyisoprene latex by pipes or agitate it in the preparation tank.

  The volume average particle size of the synthetic polyisoprene latex is preferably 0.1 to 10 μm, more preferably 0.5 to 3 μm, and further preferably 0.5 to 2.0 μm. By setting the volume average particle diameter within the above range, the latex viscosity becomes appropriate and it becomes easy to handle, and it is possible to suppress the formation of a film on the latex surface when the synthetic polyisoprene latex is stored.

Further, the synthetic polyisoprene latex contains additives such as a pH adjuster, an antifoaming agent, a preservative, a cross-linking agent, a chelating agent, an oxygen scavenger, a dispersant, and an antiaging agent, which are usually blended in the latex field. You may mix.
Examples of the pH adjusting agent include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal hydrogen carbonates such as sodium hydrogen carbonate; ammonia. Examples thereof include organic amine compounds such as trimethylamine and triethanolamine; and alkali metal hydroxides or ammonia are preferable.

  Further, as the conjugated diene polymer, as described above, a styrene-isoprene-styrene block copolymer (SIS) can also be used. In SIS, "S" represents a styrene block and "I" represents an isoprene block.

SIS can be obtained by a conventionally known method, for example, block copolymerization of isoprene and styrene in an inert polymerization solvent using an active organic metal such as n-butyllithium as an initiator. The obtained polymer solution of SIS may be used as it is for the production of SIS latex, but after taking out solid SIS from the polymer solution, the solid SIS is dissolved in an organic solvent to obtain SIS. It can also be used in the production of latex. In the present invention, it is preferable to obtain SIS in the form of a latex, that is, in the form of SIS latex from the viewpoint that the production of a latex of a carboxy-modified conjugated diene polymer is easy.
Further, when the polymer solution of SIS is obtained by the above-mentioned method, impurities such as the residue of the polymerization catalyst remaining in the polymer solution may be removed. Further, an anti-aging agent described below may be added to the solution during or after the polymerization. Further, a commercially available solid SIS can also be used.

  The method for obtaining the SIS latex containing such SIS is not particularly limited, but a solution or fine suspension of SIS dissolved or finely dispersed in an organic solvent is dissolved in water in the presence of a surfactant. A method of producing an SIS latex by emulsifying with, removing the organic solvent as necessary, is preferred.

As the organic solvent, the same ones as in the case of the synthetic polyisoprene can be used, aromatic hydrocarbon solvents and alicyclic hydrocarbon solvents are preferable, and cyclohexane and toluene are particularly preferable.
The amount of the organic solvent used is usually 50 to 2,000, preferably 80 to 1,000 parts by weight, more preferably 10 to 500 parts by weight, and further preferably 150 to 300 parts by weight with respect to 100 parts by weight of SIS. Is.

  As the surfactant, the same ones as in the case of the above-mentioned synthetic polyisoprene can be exemplified, an anionic surfactant is preferable, and sodium rosinate and sodium dodecylbenzenesulfonate are particularly preferable.

  The amount of the surfactant used is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of SIS. If this amount is too small, the stability of the latex tends to be inferior, and conversely if it is too large, foaming tends to occur, and problems may occur during film forming such as dip molding.

  The amount of water used in the method for producing SIS latex is preferably 10 to 1,000 parts by weight, more preferably 30 to 500 parts by weight, and most preferably 50 to 100 parts by weight with respect to 100 parts by weight of the organic solvent solution of SIS. Parts by weight. Examples of the type of water used include hard water, soft water, ion-exchanged water, distilled water, and zeolite water. Further, a polar solvent represented by alcohol such as methanol may be used in combination with water.

  Further, as an apparatus for emulsifying an organic solvent solution or fine suspension of SIS in water in the presence of a surfactant, the same apparatus as in the case of the above synthetic polyisoprene can be exemplified. The method of adding the surfactant is not particularly limited, and may be added in advance to either the water or the organic solvent solution of SIS or the fine suspension, or both, or during the emulsification operation, It may be added to the emulsion, added all at once, or added in portions.

  In the above-mentioned method for producing SIS latex, it is preferable to obtain the SIS latex by removing the organic solvent from the emulsion obtained through the emulsification operation. The method for removing the organic solvent from the emulsion is not particularly limited, and methods such as vacuum distillation, atmospheric distillation, steam distillation, and centrifugal separation can be adopted.

  Further, after removing the organic solvent, if necessary, in order to increase the solid content concentration of the SIS latex, concentration operation may be carried out by a method such as vacuum distillation, atmospheric distillation, centrifugation or membrane concentration.

  The solid content concentration of the SIS latex is preferably 30 to 70% by weight, more preferably 50 to 70% by weight. When the solid content concentration is too low, the solid content concentration of the latex composition of the present invention becomes low, and as a result, the film molded article such as a dip molded article obtained has a small thickness and is easily broken. On the other hand, when the solid content concentration is too high, the viscosity of the SIS latex becomes high, and it becomes difficult to transfer the SIS latex through a pipe or agitate in the preparation tank.

  In addition, the SIS latex contains additives such as a pH adjuster, an antifoaming agent, an antiseptic, a cross-linking agent, a chelating agent, an oxygen scavenger, a dispersant, and an antiaging agent, which are usually added in the latex field. May be. Examples of the pH adjusting agent include the same ones as in the case of the above-mentioned synthetic polyisoprene, and alkali metal hydroxide or ammonia is preferable.

The content of styrene units in the styrene block in SIS contained in the SIS latex thus obtained is preferably 70 to 100% by weight, more preferably 90 to 100% by weight, based on the total monomer units. , And more preferably 100% by weight.
The content of isoprene units in the isoprene block in SIS is preferably 70 to 100% by weight, more preferably 90 to 100% by weight, and even more preferably 100% by weight, based on the total monomer units.
The content ratio of the styrene unit and the isoprene unit in the SIS is usually 1:99 to 90:10, preferably 3:97 to 70:30, more preferably 5 in terms of the weight ratio of “styrene unit: isoprene unit”. : 95 to 50:50, and more preferably 10:90 to 30:70.

  The weight average molecular weight of SIS is preferably 10,000 to 1,000,000, more preferably 50,000 to 500,000, and further preferably 100,000 in terms of standard polystyrene by gel permeation chromatography analysis. ~ 300,000. By setting the weight average molecular weight of SIS within the above range, the balance between the tensile strength and flexibility of the film-formed product such as the dip-formed product is improved, and the SIS latex tends to be easily produced.

  The volume average particle diameter of the latex particles (SIS particles) in the SIS latex is preferably 0.1 to 10 μm, more preferably 0.5 to 3 μm, and further preferably 0.5 to 2.0 μm. By setting the volume average particle diameter of the latex particles within the above range, the latex viscosity becomes appropriate and the handling becomes easy, and it is possible to suppress the formation of a film on the latex surface when the SIS latex is stored.

  The nitrile group-containing conjugated diene copolymer is a copolymer obtained by copolymerizing an ethylenically unsaturated nitrile monomer with a conjugated diene monomer, and in addition to these, these are used as necessary, It may be a copolymer obtained by copolymerizing another ethylenically unsaturated monomer copolymerizable with.

  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 and chloroprene. Be done. 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 two or more kinds. The content ratio of the conjugated diene monomer unit formed by the conjugated diene monomer in the nitrile group-containing conjugated diene copolymer is preferably 56 to 78% by weight, more preferably 56 to 73% by weight. , And more preferably 56 to 68% by weight. By setting the content of the conjugated diene monomer unit within the above range, it is possible to obtain a film-formed product such as a dip-formed product that is more excellent in texture and elongation while having sufficient tensile strength. ..

  The ethylenically unsaturated nitrile monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a nitrile group, for example, acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile. And so on. Among them, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable. These ethylenically unsaturated nitrile monomers can be used alone or in combination of two or more kinds. In the nitrile group-containing conjugated diene-based copolymer, the content ratio of the ethylenically unsaturated nitrile monomer unit formed by the ethylenically unsaturated nitrile monomer is preferably 20 to 40% by weight, more preferably Is 25 to 40% by weight, and more preferably 30 to 40% by weight. By setting the content of the ethylenically unsaturated nitrile monomer unit in the above range, it is possible to obtain a film molded article such as a dip molded article, which is more excellent in elongation while having sufficient tensile strength. it can.

  Examples of the other ethylenically unsaturated monomer copolymerizable with the conjugated diene monomer and the ethylenically unsaturated nitrile monomer include, for example, an ethylenically unsaturated monomer which is an ethylenically unsaturated monomer containing a carboxyl group. Saturated carboxylic acid monomer; vinyl aromatic monomer such as styrene, alkylstyrene, vinylnaphthalene; fluoroalkyl vinyl ether such as fluoroethyl vinyl ether; (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol Ethylenically unsaturated amide monomers such as (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Butyl acrylate, 2-ethylhexyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, dibutyl maleate, dibutyl fumarate, diethyl maleate, methoxy (meth) acrylate Methyl, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, cyanomethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, (meth) 2-Ethyl-6-cyanohexyl acrylate, -3-cyanopropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth ) Ethylenically unsaturated carboxylic acid ester monomers such as acrylates; divinylbenzene, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol (meth) acrylate, etc. And the like. These ethylenically unsaturated monomers can be used alone or in combination of two or more kinds.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a carboxyl group, for example, acrylic acid, methacrylic acid and other ethylenically unsaturated monocarboxylic acid monomer Ethylenically unsaturated polycarboxylic acid monomers such as itaconic acid, maleic acid and fumaric acid; Ethylenically unsaturated polycarboxylic acid anhydrides such as maleic anhydride and citraconic anhydride; monobutyl fumarate and maleic acid Ethylenically unsaturated polyvalent carboxylic acid partial ester monomers such as monobutyl and mono-2-hydroxypropyl maleate; and the like. Among these, ethylenically unsaturated monocarboxylic acid is preferable, and methacrylic acid is particularly preferable. These ethylenically unsaturated carboxylic acid monomers can also be used as alkali metal salts or ammonium salts. Further, the ethylenically unsaturated carboxylic acid monomer may be used alone or in combination of two or more kinds.
As the other copolymerizable ethylenically unsaturated monomer, when an ethylenically unsaturated carboxylic acid monomer is used, a nitrile group-containing conjugated diene-based copolymer having a carboxyl group is used. Therefore, in this case, modification with a monomer having a carboxyl group, which will be described later, does not necessarily have to be performed.

  The content ratio of the other monomer unit formed by the other ethylenically unsaturated monomer in the nitrile group-containing conjugated diene copolymer is preferably 10% by weight or less, more preferably 5% by weight. % Or less, more preferably 3% by weight or less.

  The nitrile group-containing conjugated diene-based copolymer is obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, but by copolymerization by emulsion polymerization, a nitrile group-containing conjugated diene-based copolymer is obtained. It is preferably obtained as a copolymer latex. A conventionally known method can be adopted as the emulsion polymerization method.

  The number average particle diameter of the nitrile group-containing conjugated diene copolymer latex is preferably 60 to 300 nm, more preferably 80 to 150 nm. The particle size can be adjusted to a desired value by a method such as adjusting the amounts of the emulsifier and the polymerization initiator used.

Latex of carboxy-modified conjugated diene polymer used in the present invention is a latex of carboxy-modified conjugated diene polymer, which is obtained by modifying the above-mentioned conjugated diene polymer with a compound having a carboxyl group. It is a latex containing a polymer.

  According to the present invention, by forming the conjugated diene polymer having a carboxyl group, it is possible to suppress the generation of aggregates in the obtained latex composition, and thus the latex composition is used. In the case of producing a film-formed product such as a dip-formed product, it is possible to reduce the defect rate of the film-formed product and, moreover, to obtain a film-formed product such as a dip-formed product having improved tensile strength. be able to.

  The method for modifying the conjugated diene-based polymer with the compound having a carboxyl group is not particularly limited, and examples thereof include a method in which the conjugated diene-based polymer is graft-polymerized with the compound having a carboxyl group in an aqueous phase. .. The method of graft-polymerizing the compound having a carboxyl group in the conjugated diene polymer in the aqueous phase is not particularly limited, and a conventionally known method may be used, but the conjugated diene polymer is used in the form of latex, A method of reacting a compound having a carboxyl group with a compound having a carboxyl group and an organic peroxide in a latex of such a conjugated diene polymer, in an aqueous phase, is followed by reacting the compound having a carboxyl group with the conjugated diene polymer. preferable.

  The organic peroxide is not particularly limited, but for example, diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t. -Butyl peroxide, isobutyryl peroxide, benzoyl peroxide and the like can be mentioned, but from the viewpoint of improving the mechanical strength of the obtained dip-molded article, 1,1,3,3-tetramethylbutyl hydroperoxide is particularly preferable. .. These organic peroxides may be used alone or in combination of two or more.

  The amount of the organic peroxide added is not particularly limited, but is preferably 0.01 to 3 parts by weight, and more preferably 0 to 100 parts by weight of the conjugated diene polymer contained in the latex of the conjugated diene polymer. 0.1 to 1 part by weight.

  In addition, the organic peroxide can be used as a redox polymerization initiator in combination with a reducing agent. Although the reducing agent is not particularly limited, for example, a compound containing a metal ion in a reduced state such as ferrous sulfate and cuprous naphthenate; a sulfonic acid compound such as sodium methanesulfonate; an amine such as dimethylaniline Compounds; and the like. These reducing agents may be used alone or in combination of two or more.

  The addition amount of the reducing agent is not particularly limited, but is preferably 0.01 to 1 part by weight with respect to 1 part by weight of the organic peroxide.

  The addition method of the organic peroxide and the reducing agent is not particularly limited, and known addition methods such as batch addition, divided addition, and continuous addition can be used.

  The reaction temperature for reacting the compound having a carboxyl group with the conjugated diene-based polymer is not particularly limited, but is preferably 15 to 80 ° C, more preferably 30 to 50 ° C. The reaction time for reacting the compound having a carboxyl group with the conjugated diene polymer may be appropriately set according to the reaction temperature, but is preferably 30 to 300 minutes, more preferably 60 to 120 minutes.

  When reacting the compound having a carboxyl group with the conjugated diene polymer, the solid content concentration of the latex of the conjugated diene polymer is not particularly limited, but is preferably 5 to 60% by weight, more preferably 10 to 40% by weight. %.

Examples of compounds having a carboxyl group include ethylenically unsaturated monocarboxylic acid compounds such as acrylic acid and methacrylic acid; ethylenically unsaturated polycarboxylic acid compounds such as itaconic acid, maleic acid, fumaric acid and butenetricarboxylic acid; Partial ester compounds of ethylenically unsaturated polyvalent carboxylic acids such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate; polyvalent carboxylic acid anhydrides such as maleic anhydride and citraconic anhydride; and the like. However, the ethylenically unsaturated monocarboxylic acid compound is preferable, and acrylic acid and methacrylic acid are particularly preferable, because the effect of the present invention becomes more remarkable. The compounds having these carboxyl groups may be used alone or in combination of two or more.
Further, the above-mentioned carboxyl group also includes those which are salts with alkali metals, ammonia and the like.

  The amount of the compound having a carboxyl group is preferably 0.01 parts by weight to 100 parts by weight, more preferably 0.01 parts by weight to 40 parts by weight, further preferably 100 parts by weight of the conjugated diene polymer. It is 0.5 to 20 parts by weight. By setting the amount of the compound having a carboxyl group in the above range, the viscosity of the obtained latex composition becomes more appropriate, and it becomes easier to transfer, and the dip-formed article formed by using the obtained latex composition The tensile strength of the film molded body such as is further improved.

  The method of adding the compound having a carboxyl group to the latex of the conjugated diene polymer is not particularly limited, and known addition methods such as batch addition, divided addition and continuous addition can be adopted.

The modification ratio of the compound having a carboxyl group in the carboxy-modified conjugated diene polymer may be appropriately controlled according to the purpose of use of the latex composition obtained, but is preferably 0.01 to 10%, more preferably It is 0.05 to 7.50%, more preferably 0.1 to 5.0%. The modification rate is represented by the following formula (i).
Modification rate (mol%) = (X / Y) × 100 (i)
In the above formula (i), X represents the number of carboxyl groups in the carboxy-modified conjugated diene polymer, and Y represents the total number of monomer units in the carboxy-modified conjugated diene polymer. X can be determined by measuring the carboxy-modified conjugated diene polymer by ¹ H-NMR. Y is calculated by calculating (weight average molecular weight (Mw) of carboxy-modified conjugated diene polymer) / (average molecular weight according to content ratio of each monomer unit constituting the carboxy-modified conjugated diene polymer) You can ask.

  The polymerization catalyst used for graft polymerization (graft polymerization catalyst) is not particularly limited, but examples thereof include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; Organic peroxides such as peroxides, cumene hydroperoxide, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, isobutyryl peroxide, benzoyl peroxide, etc. Examples include oxides; azo compounds such as 2,2′-azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, and methyl azobisisobutyrate; From the viewpoint that the tensile strength of the body is further improved, organic peroxides are preferable, and 1,1,3,3-tetramethylbutyl hydroperoxide is particularly preferable.

  The above graft polymerization catalysts can be used alone or in combination of two or more kinds. The amount of the graft polymerization catalyst used varies depending on the type, but is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the conjugated diene polymer. The method for adding the graft polymerization catalyst is not particularly limited, and known addition methods such as batch addition, divided addition, and continuous addition can be adopted.

  The conversion rate of graft polymerization is preferably 95% by weight or more, more preferably 97% by weight or more. By setting the conversion rate of the graft polymerization within the above range, the tensile strength of the obtained film-formed product such as a dip-formed product is further improved.

  The carboxy-modified conjugated diene-based polymer latex used in the present invention is usually blended in the latex field, and is a pH adjuster, antifoaming agent, preservative, chelating agent, oxygen scavenger, dispersant, antiaging agent. You may mix | blend additives, such as.

  Examples of the pH adjuster include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal hydrogen carbonates such as sodium hydrogen carbonate; ammonia. Examples thereof include organic amine compounds such as trimethylamine and triethanolamine; and alkali metal hydroxides or ammonia are preferable.

  In addition, after the graft polymerization, if necessary, in order to increase the solid content concentration of the latex of the carboxy-modified conjugated diene polymer, a concentration operation is performed by a method such as vacuum distillation, atmospheric distillation, centrifugation, and membrane concentration. However, centrifugation is preferable from the viewpoint that the residual amount of the anionic surfactant in the latex of the carboxy-modified conjugated diene polymer can be adjusted.

  When the latex of the carboxy-modified conjugated diene polymer after the graft polymerization is subjected to a centrifuge, it is necessary to add a pH adjusting agent in advance to adjust the latex pH to 7 or more in order to improve the mechanical stability of the latex. It is more preferable to set the pH to 9 or higher. The carboxyl group introduced by modification when the pH of the latex is adjusted may be in a salt state.

  The solid content concentration of the latex of the carboxy-modified synthetic isoprene polymer of the present invention is preferably 30 to 70% by weight, more preferably 40 to 70% by weight. By setting the solid content concentration in the above range, generation of aggregates in the latex can be more effectively suppressed, and separation of polymer particles when the latex is stored can be more effectively suppressed.

  Further, the content ratio of the monomer unit having a carboxyl group in the carboxy-modified synthetic isoprene polymer is preferably 0.01 to 50% by weight, more preferably 0.5 to 40% by weight based on all the monomer units. %, More preferably 1 to 30% by weight, particularly preferably 1 to 15% by weight. By adjusting the content ratio of the monomer unit having a carboxyl group to the above range, the mechanical stability of the obtained latex composition is further improved, and further, the dip-molded article formed by using the obtained latex composition Flexibility and tensile strength are further improved.

Palladium Compound The latex composition of the present invention contains a palladium compound in addition to the carboxy-modified conjugated diene polymer latex described above.

  The palladium compound used in the present invention exerts a crosslinking action in the latex composition of the present invention by blending it with an oxide of a metal other than palladium described below. Therefore, according to the present invention, a sulfur-based vulcanizing agent or a sulfur-containing vulcanization accelerator (for example, a dithiocarbamate-based vulcanization accelerator, which has conventionally been a cause of delayed type allergy (Type IV) symptom, The cross-linking reaction of the carboxy-modified conjugated diene polymer can be promoted without using a thiazole vulcanization accelerator, etc., and the resulting film molded article such as a dip molded article is treated with delayed type allergy (Type IV). The occurrence of the symptom can be effectively suppressed. Further, since the latex composition of the present invention uses a carboxy-modified conjugated diene polymer which is a synthetic rubber, not a natural rubber, an immediate allergy (Type I) caused by a protein contained in the natural rubber is used. The occurrence of the symptoms of can be suppressed.

  In addition to this, according to the present invention, the compounding amount of the palladium compound in the latex composition of the present invention is from 0.01 to 2. 2 in terms of palladium element based on 100 parts by weight of the carboxy-modified conjugated diene polymer. It is the amount of 100 parts by weight, which suppresses the occurrence of symptoms of delayed type allergy (Type IV) in addition to immediate type allergy (Type I) of the obtained film molded article such as a dip molded article. However, the tensile strength is high and the elongation can be large. In the latex composition of the present invention, the compounding amount of the palladium compound is preferably 0.010 to 2.00 parts by weight in terms of palladium element, and more preferably 100 parts by weight of the carboxy-modified conjugated diene polymer. Is 0.05 to 1.50 parts by weight, and more preferably 0.1 to 1.0 parts by weight. If the compounding amount of the palladium compound is too small, the tensile strength of the resulting film molded product such as a dip molded product becomes insufficient, while if it is too large, the elongation becomes small.

The palladium compound is not particularly limited, but includes palladium metal; palladium oxide; palladium hydroxide; carboxylic acids such as palladium formate, palladium acetate, palladium propionate, palladium laurate, palladium succinate, palladium oleate, and palladium phthalate. Palladium salts; palladium chloride (PdCl ₂ ), dichloro (cyclooctadiene) palladium, dichloro (norbornadiene) palladium, hexachloropalladium (IV) acid ammonium and other palladium chlorides; palladium bromide and other palladium bromides; palladium iodide, etc. Palladium iodide; Palladium salts of inorganic acids such as palladium sulfate and palladium nitrate; Palladium (II) acetylacetonate; M ₂ PdCl ₄ (M = H, Li, Na, K), M ₂ PdCl ₆ (M = H, Li, Na, K), Pd (PPh ₃ ) ₄ , Pd (PPh ₃ ) ₃ X, Pd (PPh ₃ ) ₂ X ₂ (X = I, Br, Cl, OAc), n-allyl Pd complex and other complexes Compounds; supported palladium compounds such as Pd / CaCO ₃ , Pd / carbon, and Pd / SiO ₂ ; and the like. Among these, from the viewpoint that the effect of improving tensile strength and elongation is large, palladium salts of carboxylic acids, palladium chlorides, palladium bromides, palladium salts of inorganic acids are preferred, and palladium chlorides, palladium bromides are more preferred, and chlorides are preferred. Palladium (PdCl ₂ ) is particularly preferred.

  In the latex composition of the present invention, the compounding method of the palladium compound is not particularly limited as long as it is a method in which the latex of the carboxy-modified conjugated diene polymer and the metal oxide are finally mixed. For example, a method of obtaining a latex of a carboxy-modified conjugated diene polymer and then blending a metal oxide with the latex of the carboxy-modified conjugated diene polymer can be used. Further, from the viewpoint that the palladium compound can be suitably dispersed in the latex composition, it is preferable to add it to the latex of the carboxy-modified conjugated diene polymer in the state of an aqueous solution or an aqueous dispersion. When palladium chloride is used as the palladium compound, it is preferable to use sodium chloride, hydrochloric acid, or the like in combination to form an aqueous solution or an aqueous dispersion with improved solubility. ..

Oxides of Metals Other Than Palladium The latex composition of the present invention is a latex of the above-mentioned carboxy-modified conjugated diene-based polymer, and, in addition to the palladium compound, oxides of metals other than palladium (hereinafter referred to as “metal oxide”). ).

  The metal oxide, together with the above-described palladium compound, has a cross-linking effect in the latex composition of the present invention, and by using these in combination, a film molded article such as a dip molded article obtained has a tensile strength of It can be high and highly stretchable.

  The metal oxide may be an oxide of a metal other than palladium, and is not particularly limited, but zinc oxide, magnesium oxide, titanium oxide, calcium oxide, lead oxide, iron oxide, copper oxide, tin oxide, nickel oxide. , Chromium oxide, cobalt oxide, and aluminum oxide. Among these, zinc oxide is preferable from the viewpoint of further improving the tensile strength of the film-formed product such as the obtained dip-formed product. These metal oxides may be used alone or in combination of two or more.

  The content ratio of the metal oxide in the latex composition of the present invention is preferably 0.01 to 30 parts by weight, more preferably 0. 0, based on 100 parts by weight of the carboxy-modified conjugated diene polymer contained in the latex. It is 1 to 20 parts by weight, and more preferably 0.5 to 15 parts by weight. By setting the content ratio of the metal oxide within the above range, it is possible to further improve the tensile strength of the obtained film-formed product such as a dip-formed product.

  In the latex composition of the present invention, the method for blending the metal oxide may be any method as long as it is a state in which the latex of the carboxy-modified conjugated diene polymer and the metal oxide are finally mixed, but is not particularly limited. For example, a method of obtaining a latex of a carboxy-modified conjugated diene polymer and then blending a metal oxide into the latex of the carboxy-modified conjugated diene polymer can be used. Further, when the metal oxide is blended, it may be blended in the state of an aqueous solution or an aqueous dispersion.

Latex Composition The latex composition of the present invention comprises the above-mentioned latex of the carboxy-modified conjugated diene polymer, a palladium compound, and an oxide of a metal other than palladium.

  The latex composition of the present invention may contain a latex of a carboxy-modified conjugated diene polymer, a palladium compound, and an oxide of a metal other than palladium. In addition to these, an antiaging agent; A compounding agent such as a dispersant; a reinforcing agent such as carbon black, silica, or talc; a filler such as calcium carbonate or clay; an ultraviolet absorber; a plasticizer;

  As the antiaging agent, 2,6-di-4-methylphenol, 2,6-di-t-butylphenol, butylhydroxyanisole, 2,6-di-t-butyl-α-dimethylamino-p-cresol, Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2,2′-methylene-bis (6-α-methyl-benzyl-p-cresol), 4, Butylation of 4'-methylene bis (2,6-di-t-butylphenol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), alkylated bisphenol, p-cresol and dicyclopentadiene Sulfur atom-free phenolic antioxidants such as reaction products; 2,2'-thiobis- (4-methyl-6-t-butylphenol), 4,4'-thiobis- (6-t-butyl-) o-cresol), 2,6-di-t-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol and other thiobisphenol antioxidants; Tris (Nonylphenyl) phosphite, diphenylisodecylphosphite, tetraphenyldipropylene glycol / diphosphite, and other phosphite antioxidants; sulfur ester antiaging agents, such as dilauryl thiodipropionate; phenyl-α-naphthylamine, Phenyl-β-naphthylamine, p- (p-toluenesulfonylamide) -diphenylamine, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine, N, N-diphenyl-p-phenylenediamine, N-isopropyl-N ′ -Amine-based antioxidants such as phenyl-p-phenylenediamine and butyraldehyde-aniline condensates; quinoline-based antioxidants such as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; 5-di- (t-amyl) hydroquinone and other hydroquinone antiaging agents; and the like. These antioxidants can be used alone or in combination of two or more.

  The content of the antioxidant is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the carboxy-modified conjugated diene polymer.

  Further, the latex composition of the present invention may contain a sulfur-based vulcanizing agent and a sulfur-containing vulcanization accelerator, but from the viewpoint of further increasing the effect of suppressing the symptoms of delayed allergy (Type IV), The total content of the sulfur-based vulcanizing agent and the sulfur-containing vulcanization accelerator is preferably 0.5 parts by weight or less and is 0.1 parts by weight or less based on 100 parts by weight of the carboxy-modified conjugated diene polymer. More preferably, it is not compounded at all, and substantially neither a sulfur-based vulcanizing agent nor a sulfur-containing vulcanization accelerator is contained. Even in this case, the sulfur-based vulcanizing agent and the sulfur-containing vulcanization accelerator (for example, 0.1 wt ppm or less in terms of sulfur element), the sulfur-based vulcanizing agent and the sulfur-based vulcanizing agent and the sulfur-containing vulcanizing agent and the sulfur-containing vulcanizing agent and the vulcanizing agent and the sulfur-containing vulcanizing agent and the sulfur-containing vulcanizing agent and the vulcanizing agent and the vulcanizing agent and the vulcanizing agent and the vulcanization agent Sulfur other than the sulfur vulcanization accelerator (for example, derived from an emulsifier) may contain sulfur or a sulfur compound.

  Examples of the sulfur-based vulcanizing agent include sulfur powder, sulfur flower, precipitated sulfur, colloidal sulfur, surface-treated sulfur, sulfur such as insoluble sulfur; sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, caprolactam disulfide (N , N'-dithio-bis (hexahydro-2H-azepinone-2)), phosphorus-containing polysulfides, polymeric polysulfides, and sulfur-containing compounds such as 2- (4'-morpholinodithio) benzothiazole.

  Examples of the sulfur-containing vulcanization accelerator include dithiocarbamic acids such as diethyldithiocarbamic acid, dibutyldithiocarbamic acid, di-2-ethylhexyldithiocarbamic acid, dicyclohexyldithiocarbamic acid, diphenyldithiocarbamic acid, dibenzyldithiocarbamic acid and zinc salts thereof; 2 -Mercaptobenzothiazole, 2-mercaptobenzothiazole zinc, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2- (2,4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthiocarbaylthio) benzothiazole , 2- (2,6-dimethyl-4-morpholinothio) benzothiazole, 2- (4'-morpholinodithio) benzothiazole, 4-morphonylyl-2-benzothiazyl disulfide, 1,3-bis (2-benzothiazyl) -Mercaptomethyl) urea and the like.

  The method for preparing the latex composition of the present invention is not particularly limited, but the latex of the carboxy-modified conjugated diene polymer is added to an aqueous solution or dispersion of a palladium compound, and an oxide of a metal other than palladium. , A ball mill, a kneader, a method of mixing various compounding agents to be blended as needed using a disperser such as Disper, and using such a disperser, other than the latex of the carboxy-modified conjugated diene polymer A method of preparing an aqueous dispersion of the components and then mixing the aqueous dispersion with a latex of a carboxy-modified conjugated diene polymer can be used.

  The latex composition of the present invention has a solid content concentration of preferably 10 to 60% by weight, more preferably 10 to 55% by weight.

The latex composition of the present invention is preferably aged (pre-crosslinked) before being subjected to dip molding, from the viewpoint of further enhancing the mechanical properties of the obtained film molded article such as a dip molded article. The time for pre-crosslinking is not particularly limited and depends on the temperature of pre-crosslinking, but is preferably 1 to 14 days, more preferably 1 to 7 days. The temperature of pre-crosslinking is preferably 20 to 40 ° C.
After pre-crosslinking, it is preferable to store at a temperature of 10 to 30 ° C. until it is subjected to dip molding. If it is stored at a high temperature, the tensile strength of the resulting film-molded product such as a dip-molded product may decrease.

Film-Molded Product The film-molded product of the present invention is a film-shaped molded product made of the latex composition of the present invention. The film molded product of the present invention has a thickness of preferably 0.03 to 0.50 mm, more preferably 0.05 to 0.40 mm, and particularly preferably 0.08 to 0.30 mm.

  The film-molded product of the present invention is not particularly limited, but a dip-molded product obtained by dip-molding the latex composition of the present invention is preferable. Dip molding is a method of immersing a mold in a latex composition, depositing the composition on the surface of the mold, then pulling up the mold from the composition, and then drying the composition deposited on the surface of the mold. is there. The mold before being immersed in the latex composition may be preheated. Further, a coagulant can be used if necessary before the mold is immersed in the latex composition or after the mold is pulled out from the latex composition.

  Specific examples of the method of using the coagulant include a method in which the mold before being immersed in the latex composition is immersed in a solution of the coagulant to attach the coagulant to the mold (anode coagulation dipping method), and a latex composition is deposited. Although there is a method of immersing the formed mold in a coagulant solution (Teag coagulation dipping method), the anode coagulation dipping method is preferable from the viewpoint that a dip molded body with less thickness unevenness can be obtained.

  Specific examples of the coagulant include metal halides such as barium chloride, calcium chloride, magnesium chloride, zinc chloride and aluminum chloride; nitrates such as barium nitrate, calcium nitrate and zinc nitrate; acetic acid such as barium acetate, calcium acetate and zinc acetate. Salts; water-soluble polyvalent metal salts such as calcium sulfate, magnesium sulfate, and aluminum sulfate. Among them, calcium salt is preferable, and calcium nitrate is more preferable. These water-soluble polyvalent metal salts may be used alone or in combination of two or more.

  The coagulant can be usually used as a solution of water, alcohol, or a mixture thereof, and is preferably used as an aqueous solution. This aqueous solution may further contain a water-soluble organic solvent such as methanol or ethanol, or a nonionic surfactant. The concentration of the coagulant varies depending on the type of the water-soluble polyvalent metal salt, but is preferably 5 to 50% by weight, more preferably 10 to 30% by weight.

  After withdrawing the mold from the latex composition, it is typically heated to dry the deposit formed on the mold. The drying conditions may be appropriately selected.

  Next, the obtained dip-molded layer is subjected to heat treatment to be crosslinked. Before applying the heat treatment, the water-soluble impurities (for example, excess emulsifier, coagulant, etc.) may be removed by immersing in water, preferably hot water at 30 to 70 ° C., for about 1 to 60 minutes. The operation of removing the water-soluble impurities may be performed after the dip-molded layer is subjected to the heat treatment, but it is preferably performed before the heat treatment because the water-soluble impurities can be removed more efficiently.

  Crosslinking of the dip-molded layer is usually carried out at a temperature of 80 to 150 ° C., preferably by a heat treatment for 10 to 130 minutes. As a heating method, a method of external heating with infrared rays or heated air or internal heating with high frequency can be adopted. Of these, external heating with heated air is preferable.

Then, by removing the dip molding layer from the dip molding die, the dip molding is obtained as a film-shaped film molding. As the desorption method, a method of peeling from the molding die by hand or a method of peeling with water pressure or compressed air pressure can be adopted. After desorption, heat treatment may be further performed at a temperature of 60 to 120 ° C. for 10 to 120 minutes.
In addition to the method of dip-molding the latex composition of the present invention described above, the film-molded product of the present invention can be formed into a film by the latex composition of the present invention described above (for example, a coating method or the like). In any case, it may be obtained by any method.

  Since the film-molded product of the present invention is obtained by using the above-mentioned latex composition of the present invention, it has high tensile strength and high elongation, and therefore can be particularly suitably used as a glove. When the film-molded body is a glove, inorganic particles such as talc and calcium carbonate or organic particles such as starch particles are used to prevent the film-molded bodies from adhering to each other at the contact surface and to improve the slippage during attachment / detachment. It may be sprayed on the surface, an elastomer layer containing fine particles may be formed on the surface of the glove, or the surface layer of the glove may be chlorinated.

  In addition to the above gloves, the film-molded product of the present invention is a medical product such as a nipple for baby bottles, a dropper, a tube, a water pillow, a balloon sack, a catheter, a condom; a toy such as a balloon, a doll, or a ball; It can also be used for industrial products such as molding bags and gas storage bags; finger cots and the like.

Adhesive Composition In the present invention, the above-mentioned latex composition of the present invention can be used as an adhesive composition.

  The content (solid content) of the latex composition in the adhesive composition is preferably 5 to 60% by weight, more preferably 10 to 30% by weight.

  The adhesive composition preferably contains an adhesive resin in addition to the latex composition of the present invention. The adhesive resin is not particularly limited, but for example, resorcin-formaldehyde resin, melamine resin, epoxy resin and isocyanate resin can be preferably used, and among these, resorcin-formaldehyde resin is preferable. As the resorcin-formaldehyde resin, known resins (for example, those disclosed in JP-A-55-142635) can be used. The reaction ratio of resorcin and formaldehyde is a molar ratio of "resorcin: formaldehyde" and is usually 1: 1 to 1: 5, preferably 1: 1 to 1: 3.

  Further, in order to further enhance the adhesive strength of the adhesive composition, the adhesive composition contains 2,6-bis (2,4-dihydroxyphenylmethyl) -4-chlorophenol or a similar compound which has been conventionally used. Compounds, isocyanates, blocked isocyanates, ethylene urea, polyepoxides, modified polyvinyl chloride resins and the like can be contained.

  Further, the adhesive composition may contain a vulcanization aid. By including the vulcanization aid, the mechanical strength of the composite described below obtained using the adhesive composition can be improved. Examples of the vulcanization aid include quinone dioximes such as p-quinone dioxime; methacrylic acid esters such as lauryl methacrylate and methyl methacrylate; DAF (diallyl fumarate), DAP (diallyl phthalate), TAC (triallyl cyanurate), Allyl compounds such as TAIC (triallyl isocyanurate); maleimide compounds such as bismaleimide, phenylmaleimide, N, N-m-phenylene dimaleimide; and the like.

Adhesive Layer-Forming Substrate The adhesive layer-forming substrate of the present invention is obtained by forming an adhesive layer formed using the latex composition or the adhesive composition of the present invention on the surface of the substrate.

  The base material is not particularly limited, but a fiber base material can be used, for example. The type of fiber constituting the fiber base material is not particularly limited, and examples thereof include polyamide fiber such as vinylon fiber, polyester fiber, nylon, aramid (aromatic polyamide), glass fiber, cotton, rayon and the like. These can be appropriately selected according to the application. The shape of the fiber base material is not particularly limited, and examples thereof include staples, filaments, cords, ropes, woven fabrics (sailcloths, etc.), etc., and can be appropriately selected depending on the application.

  The adhesive layer-forming substrate of the present invention can be used as a substrate-rubber composite by, for example, adhering to rubber via an adhesive layer. The base material-rubber composite is not particularly limited, but for example, a rubber toothed belt with a core wire using a cord-shaped fiber base material, a rubber using a base cloth-shaped fiber base material such as canvas. Examples include toothed belts.

  The method for obtaining the base material-rubber composite is not particularly limited, but for example, the latex composition or the adhesive composition of the present invention is attached to the base material by dipping treatment or the like to obtain a base material for forming an adhesive layer. The method of placing the adhesive layer-forming base material on rubber and heating and pressurizing it. Pressurization can be performed using a compression (press) molding machine, a metal roll, an injection molding machine, or the like. The pressure applied is preferably 0.5 to 20 MPa, more preferably 2 to 10 MPa. The heating temperature is preferably 130 to 300 ° C, more preferably 150 to 250 ° C. The processing time of heating and pressurization is preferably 1 to 180 minutes, more preferably 5 to 120 minutes. By the method of heating and pressurizing, the molding of rubber and the adhesion of the adhesive layer-forming base material to the rubber can be performed at the same time. In addition, it is preferable to form a mold for imparting a desired surface shape to the rubber of the target base material-rubber composite on the inner surface of the mold of the compressor used for pressurization or the surface of the roll.

  Moreover, a base material-rubber-base material composite material can be mentioned as an aspect of the base material-rubber composite material. The base material-rubber-base material composite can be formed, for example, by combining a base material (which may be a composite of two or more base materials) and a base material-rubber composite. Specifically, a core wire as a base material, rubber and a base cloth as a base material are stacked (at this time, the latex composition or the adhesive composition of the present invention is appropriately adhered to the core wire and the base cloth to form an adhesive. A base material-rubber-base material composite can be obtained by applying a layer-forming base material) and applying pressure while heating.

  The base material-rubber composite obtained using the adhesive layer-forming base material of the present invention is excellent in mechanical strength, abrasion resistance and water resistance, and therefore, a flat belt, a V belt, a V ribbed belt, It can be suitably used as a belt such as a round belt, a square belt, and a toothed belt. Furthermore, the base material-rubber composite obtained using the adhesive layer-forming base material of the present invention can be suitably used for hoses, tubes, diaphragms and the like. Examples of the hose include a single-tube rubber hose, a multi-layer rubber hose, a braided type reinforcement hose, and a cloth wound type reinforcement hose. Examples of the diaphragm include a flat diaphragm and a rolling diaphragm.

  The base material-rubber composite obtained using the adhesive layer-forming base material of the present invention can be used as an industrial product such as a seal or a rubber roll, in addition to the above-mentioned applications. Examples of the seal include a moving part seal such as a rotating part, a swinging part, and a reciprocating part and a fixed part seal. Examples of the moving part seal include an oil seal, a piston seal, a mechanical seal, a boot, a dust cover, a diaphragm, an accumulator and the like. Examples of the fixed part seal include O-rings and various gaskets. Examples of rubber rolls include rolls that are parts of OA equipment such as printing equipment and copying equipment; fiber processing rolls such as spinning rolls for drawing and draft rolls for spinning; iron-making rolls such as bridle rolls, snubber rolls, and steering rolls. Can be mentioned.

  Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples. In addition, the following "parts" are based on weight unless otherwise specified. In addition, various physical properties were measured as follows.

2 g of the sample was precisely weighed (weight: X2) in a solid content aluminum dish (weight: X1) and dried in a hot air dryer at 105 ° C. for 2 hours. Then, after cooling in a desiccator, the weight of each aluminum dish was measured (weight: X3), and the solid content concentration was calculated according to the following calculation formula.
Solid content concentration (% by weight) = (X3−X1) × 100 / X2

Aggregate content ratio After the latex composition was allowed to stand at 30 ° C. for 7 days, the solid content concentration of the latex composition was measured according to the method described above, 100 g of the latex composition was precisely weighed, and then 200 mesh of known weight was used. Was filtered with a SUS wire mesh of No. 3, and the aggregate on the wire mesh was washed several times with water to remove the latex composition. After drying this at 105 ° C. for 2 hours or more, the dry weight thereof was measured, and the aggregate content ratio (unit: weight%) was determined based on the following formula.
Aggregate content ratio (% by weight) = {(α-β) / (γ × Δ)} × 10,000
Here, α is the weight of the dried wire net and the dried aggregate, β is the weight of the wire net, γ is the weight of the latex composition, and Δ is the solid content concentration (% by weight) of the latex composition.

Patch test A test piece obtained by cutting a film-shaped dip-molded body having a film thickness of about 0.2 mm into a size of 10 × 10 mm was attached to each arm of 10 examinees. Then, 48 hours later, the adhered portion was observed to confirm the occurrence of allergic symptoms of delayed type allergy (Type IV), and evaluated according to the following criteria.
A: All subjects did not have allergic symptoms.
B: Allergic symptoms were observed in some of the subjects.

Based on the tensile strength and elongation ASTM D412 of the dip molded product, a film-shaped dip molded product with a film thickness of about 0.2 mm was dumbbelled (trade name "Super Dumbbell (Model: SDMK-100C)", manufactured by Dumbbell). Then, a test piece for tensile strength measurement was prepared. The test piece was pulled with a Tensilon universal testing machine (trade name "RTG-1210", manufactured by Orientec Co., Ltd.) at a tensile speed of 500 mm / min, the tensile strength (unit: MPa) immediately before breaking and the elongation (unit: immediately before breaking). %) Was measured.

Production example 1
Production of carboxy-modified synthetic polyisoprene (A-1) latex Synthetic polyisoprene having a weight average molecular weight of 1,300,000 (trade name "NIPOL IR2200L", manufactured by Nippon Zeon Co., isoprene homopolymer, cis-bond unit) (Amount 98%) is mixed with cyclohexane, the temperature is raised to 60 ° C. with stirring to dissolve, and a cyclohexane solution (a) of synthetic polyisoprene having a viscosity of 12,000 mPa · s measured by a B-type viscometer is dissolved. It was prepared (solid content concentration 8% by weight).

  On the other hand, 20 parts of sodium rosinate was added to water and the temperature was raised to 60 ° C. to dissolve it to prepare an anionic surfactant aqueous solution (b) having a concentration of 1.5% by weight.

  Next, the cyclohexane solution (a) and the anionic surfactant aqueous solution (b) were mixed at a weight ratio of 1: 1.5 by a mixer (trade name "Multiline Mixer MS26-MMR-5". .5L ", manufactured by Satake Chemical Machinery Co., Ltd., and then mixed and emulsified at a rotation speed of 4,100 rpm using an emulsifying device (trade name" Milder MDN310 ", manufactured by Taihei Kiki Co., Ltd.). Then, an emulsion (c) was obtained. At that time, the total feed flow rate of the synthetic polyisoprene cyclohexane solution (a) and the anionic surfactant aqueous solution (b) was 2,000 kg / hr, the temperature was 60 ° C., and the back pressure (gauge pressure) was 0. It was set to 5 MPa.

  Next, the emulsion (c) is heated to 80 ° C. under reduced pressure of −0.01 to −0.09 MPa (gauge pressure), cyclohexane is distilled off, and an aqueous dispersion (d) of synthetic polyisoprene is obtained. Obtained. At that time, an antifoaming agent (trade name "SM5515", manufactured by Toray Dow Corning Co., Ltd.) was continuously added while spraying so that the amount of the synthetic polyisoprene in the emulsion (c) was 300 ppm by weight. .. When the cyclohexane is distilled off, the emulsion (c) is adjusted to 70% by volume or less of the volume of the tank, and a 3-stage inclined paddle blade is used as the stirring blade, and the mixture is slowly stirred at 60 rpm. Was carried out.

  Then, after the distillation of cyclohexane is completed, the aqueous dispersion (d) of the obtained synthetic polyisoprene is used in a continuous centrifuge (trade name “SRG510”, manufactured by Alfa Laval Co., Ltd.) at 4,000- After centrifugation at 5,000 G, a synthetic polyisoprene latex (e) was obtained as a light liquid. The centrifugation conditions are as follows: the solid concentration of the aqueous dispersion (d) before centrifugation is 10% by weight, the flow rate during continuous centrifugation is 1,300 kg / hr, and the back pressure (gauge pressure) of the centrifuge is It was set to 1.5 MPa. The obtained synthetic polyisoprene latex (e) had a solid content concentration of 60% by weight.

  Then, 850 parts of distilled water was added to 100 parts of the synthetic polyisoprene in the obtained latex (e) of the synthetic polyisoprene for dilution. The diluted latex was charged into a nitrogen-substituted polymerization reaction vessel equipped with a stirrer, and the temperature was raised to 30 ° C. with stirring. Further, using another container, 2 parts of methacrylic acid and 16 parts of distilled water were mixed to prepare a methacrylic acid diluted solution. This methacrylic acid diluted solution was added to the polymerization reaction container heated to 30 ° C. over 30 minutes.

  Furthermore, using another container, 7 parts of distilled water, 0.32 parts of sodium formaldehyde sulfoxylate (trade name "SFS", manufactured by Mitsubishi Gas Chemical Co., Inc.), ferrous sulfate (trade name "Frost Fe", central part Kirest) A solution (f) consisting of 0.01 part (manufactured by the company) was prepared. After adding this solution (f) into the polymerization reaction vessel, 0.5 part of 1,1,3,3-tetramethylbutyl hydroperoxide (trade name "Perocta H", manufactured by NOF CORPORATION) was added. The reaction was carried out at 30 ° C. for 1 hour and further at 70 ° C. for 2 hours to graft-polymerize methacrylic acid on the synthetic polyisoprene.

Then, after adding sodium hydroxide to adjust the pH to 10, this was centrifuged at 4,000 to 5,000 G using a continuous centrifuge (trade name "SRG510", manufactured by Alfa Laval). The flow rate was 1700 kg / hr and the back pressure (gauge pressure) of the centrifugal separator was 0.08 MPa) to obtain a latex of carboxy-modified synthetic polyisoprene (A-1) having a solid content concentration of 55% by weight. In the carboxy-modified synthetic polyisoprene (A-1) contained in the obtained latex, the modification rate with methacrylic acid determined according to the following formula (i) was 0.2%.
Denaturation rate (%) = (X / Y) × 100 (i)
In the above formula (i), X represents the number of carboxyl groups in the carboxy-modified synthetic polyisoprene, and Y represents the total number of monomer units in the carboxy-modified synthetic polyisoprene.

Production example 2
Production of Latex of Carboxy-Modified Synthetic Polyisoprene (A-2) Carboxy-modified synthetic poly ( solid content 55% by weight) was produced in the same manner as in Production Example 1 except that the amount of methacrylic acid used was changed from 2 parts to 5 parts. A latex of isoprene (A-2) was obtained. The carboxy-modified synthetic polyisoprene (A-2) contained in the obtained latex had a modification rate with methacrylic acid of 1%, which was determined according to the above formula (i).

Production Example 3
Production of Latex of Carboxy-Modified Synthetic Polyisoprene (A-3) Carboxy-modified synthetic poly with a solid content concentration of 55 wt% was prepared in the same manner as in Production Example 1 except that the amount of methacrylic acid used was changed from 2 parts to 10 parts. A latex of isoprene (A-3) was obtained. The carboxy-modified synthetic polyisoprene (A-3) contained in the obtained latex had a modification rate with methacrylic acid of 5%, which was determined according to the above formula (i).

Example 1
Preparation of Latex Composition To a glass container, 2.64 parts of palladium chloride (PdCl ₂ ) and 4.4 parts of sodium chloride, and 82 parts of ion-exchanged water were added, and the mixture was stirred at room temperature for 24 hours to form chloride. An aqueous dispersion of palladium was obtained.

  Separately from the above, styrene-maleic acid mono-sec-butyl ester-maleic acid monomethyl ester polymer (trade name "Scripset 550", manufactured by Hercules) is used, and sodium carboxylate is used, and the carboxyl group in the polymer is 100%. After neutralization, an aqueous sodium salt solution (concentration: 10% by weight) as a dispersant (g) was prepared. Then, the sodium salt aqueous solution of the dispersant (g) was added to the latex of the carboxy-modified synthetic polyisoprene (A-1) obtained in Production Example 1 with respect to 100 parts of the carboxy-modified synthetic polyisoprene (A-1). A mixture was obtained by adding 0.8 parts in terms of solid content.

  Then, while stirring the obtained mixture, an aqueous dispersion of palladium chloride was converted to 0.5 part (palladium atom conversion) based on 100 parts of the carboxy-modified synthetic polyisoprene (A-1) in the mixture. 0.3 part). Next, an aqueous dispersion of zinc oxide as a metal oxide was added in an amount of 1.5 parts in terms of zinc oxide to obtain a latex composition. Then, a part of the obtained latex composition was sampled, and the content of aggregates was measured according to the above method. The results are shown in Table 1.

Manufacture of Dip Molded Product A commercially available ceramic hand mold (manufactured by Shinko Co., Ltd.) was washed and preheated in an oven at 70 ° C., then 18 wt% calcium nitrate and 0.05 wt% polyoxyethylene lauryl ether ( It was immersed for 5 seconds in a coagulant aqueous solution containing a trade name "Emulgen 109P" (manufactured by Kao Corporation) and taken out from the coagulant aqueous solution. Next, the hand mold was dried in an oven at 70 ° C. for 30 minutes or more to adhere the coagulant to the hand mold and coat the hand mold with the coagulant.

  Thereafter, the hand mold coated with the coagulant was taken out of the oven and immersed in the latex composition obtained above for 10 seconds. At this time, the latex composition obtained above was aged in a constant temperature water bath adjusted to 30 ° C. for 48 hours. Next, the hand mold was air-dried at room temperature for 10 minutes, and then immersed in warm water at 60 ° C. for 5 minutes to elute the water-soluble impurities to form a dip molding layer on the hand mold. After that, the dip molding layer formed in the hand mold is crosslinked by heating in an oven at a temperature of 130 ° C. for 30 minutes, then cooled to room temperature, sprinkled with talc, and then peeled from the hand mold. A dip molded body (rubber glove) was obtained. Then, with respect to the obtained dip-molded body (rubber glove), each of the patch test, the tensile strength and the elongation were evaluated according to the above-mentioned methods. The results are shown in Table 1.

Example 2
When preparing a latex composition, the carboxy-modified synthetic polyisoprene (A-2) obtained in Production Example 2 was replaced with the carboxy-modified synthetic polyisoprene (A-1) latex obtained in Production Example 1. A latex composition and a dip molded article (rubber glove) were produced in the same manner as in Example 1 except that latex (100 parts in terms of carboxy-modified synthetic polyisoprene (A-2)) was used, and evaluated in the same manner. went. The results are shown in Table 1.

Example 3
When preparing the latex composition, the carboxy-modified synthetic polyisoprene (A-3) obtained in Production Example 3 was replaced with the carboxy-modified synthetic polyisoprene (A-1) latex obtained in Production Example 1. A latex composition and a dip molded article (rubber glove) were produced in the same manner as in Example 1 except that latex (100 parts in terms of carboxy-modified synthetic polyisoprene (A-3)) was used, and evaluated in the same manner. went. The results are shown in Table 1.

Comparative Example 1
When preparing a latex composition, instead of the latex of the carboxy-modified synthetic polyisoprene (A-1) obtained in Production Example 1, the synthetic polyisoprene obtained in Production Example 1 before carboxy modification was used. A latex composition and a dip molded article (rubber glove) were produced and evaluated in the same manner as in Example 1 except that the latex (e) (100 parts in terms of synthetic polyisoprene) was used as it was. The results are shown in Table 1.

Comparative example 2
When the latex composition was prepared, the same procedure as in Example 2 was performed except that the amount of the aqueous dispersion of palladium chloride used was 0.013 parts in terms of palladium chloride compound (0.008 parts in terms of palladium atom). Then, a latex composition and a dip molded article (rubber glove) were produced and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 3
When preparing the latex composition, 1.5 parts of sulfur and 1.5 parts of a sulfur-containing vulcanization accelerator (0.3 parts of zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate) were used instead of the aqueous dispersion of palladium chloride. A latex composition and a dip molded article (rubber glove) were produced in the same manner as in Example 2 except that 0.5 part and 2-mercaptobenzothiazole zinc (0.7 part) were used, and evaluated in the same manner. went. The results are shown in Table 1.

  As shown in Table 1, containing a latex of a carboxy-modified conjugated diene polymer, a palladium compound, and an oxide of a metal other than palladium, and containing a palladium compound with respect to 100 parts by weight of the carboxy-modified conjugated diene polymer. The latex composition having a ratio of 0.01 to 2.00 parts by weight in terms of palladium element is excellent in stability because the generation of aggregates is suppressed, and further, the latex composition is The dip-molded product produced by using the dip-molded product had good patch test results, so that the occurrence of delayed type allergy (Type IV) was suppressed, and the tensile strength and elongation were high ( Examples 1-3).

On the other hand, in place of the latex of the carboxy-modified conjugated diene polymer, the latex composition obtained by using the latex of the synthetic polyisoprene which has not been carboxy-modified has a large amount of aggregates and is inferior in stability. Further, the dip-molded article produced by using the latex composition had poor tensile strength (Comparative Example 1).
Moreover, when the compounding amount of the palladium compound was less than 0.01 part by weight, the dip-molded article produced using the obtained latex composition was inferior in tensile strength (Comparative Example 2).
Furthermore, when a sulfur-based vulcanizing agent and a sulfur-containing vulcanization accelerator were blended in place of the palladium compound, the dip-molded article produced using the obtained latex composition showed a delay from the patch test results. The symptoms of type IV allergy (Type IV) were generated (Comparative Example 3).

Claims (7)

A latex composition containing a carboxy-modified conjugated diene polymer latex, a palladium compound, and an oxide of a metal other than palladium,
A latex composition in which the content ratio of the palladium compound relative to 100 parts by weight of the carboxy-modified conjugated diene polymer is 0.01 to 2.00 parts by weight in terms of palladium element.   The latex composition according to claim 1, wherein the total content of the sulfur-based vulcanizing agent and the sulfur-containing vulcanization accelerator is 0.5 part by weight or less based on 100 parts by weight of the carboxy-modified conjugated diene polymer.   The latex composition according to claim 1 or 2, wherein the carboxy-modified conjugated diene polymer is a carboxy-modified synthetic polyisoprene.   The latex composition according to claim 1, wherein the carboxy-modified conjugated diene-based polymer has a modification rate of 0.01 to 10%.   The latex composition according to claim 1, wherein a content ratio of an oxide of a metal other than palladium is 0.01 to 30 parts by weight with respect to 100 parts by weight of the carboxy-modified conjugated diene polymer.   A film molded body comprising the latex composition according to claim 1.   An adhesive layer-forming substrate comprising an adhesive layer comprising the latex composition according to claim 1 formed on the surface of the substrate.