JP2019034982A - Latex composition - Google Patents

Abstract

To provide a latex composition capable of suppressing generation of symptom of delayed type allergy (Type IV) in addition to immediate type allergy (Type I), and capable of providing a film molded body such as a dip molded body high in tensile strength and excellent in durability, and the film molded body using the latex composition.SOLUTION: There is provided a latex composition containing latex of a carboxyl group-containing nitrile rubber and hypochlorite.SELECTED DRAWING: None

Description

  The present invention relates to a latex composition. More specifically, the present invention relates to a latex composition capable of providing a film molded article such as a dip molded article having high tensile strength and excellent durability, and a film using the latex composition. It relates to a molded body.

  Conventionally, a film molded body obtained by molding a latex composition containing latex of natural rubber into a film shape is known. For example, as a film molded body, a dip molded body obtained by dip molding a latex composition containing natural rubber latex and used in contact with a human body such as a nipple, a balloon, a glove, a balloon, and a sac is known. It has been. However, since latex of natural rubber contains a protein that causes symptoms of immediate allergy (Type I) in the human body, there are cases where there is a problem as a dip-molded body that is in direct contact with living mucous membranes or organs. Therefore, studies have been made on using synthetic rubber latex instead of natural rubber latex.

  For example, Patent Document 1 discloses a latex composition in which zinc oxide, sulfur, and a vulcanization accelerator are blended with a synthetic polyisoprene latex, which is a synthetic rubber, as a dip molding composition. However, the technique of Patent Document 1 can prevent the occurrence of 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 used. For this reason, when the human body is touched, allergic symptoms of delayed type allergy (Type IV) may occur.

International Publication No. 2014/129547

  The present invention has been made in view of such a situation, and can suppress the occurrence of symptoms of delayed allergy (Type IV) in addition to immediate allergy (Type I), and has high tensile strength. Another object of the present invention is to provide a latex composition capable of providing a film molded body such as a dip molded body having excellent durability, and a film molded body using the latex composition.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by a latex composition in which hypochlorite is blended with a latex of a carboxyl group-containing nitrile rubber, The present invention has been completed.

  That is, according to the present invention, there is provided a latex composition containing a latex of a carboxyl group-containing nitrile rubber and a hypochlorite.

In the latex composition of the present invention, the content ratio of the hypochlorite with respect to 100 parts by weight of the carboxyl group-containing nitrile rubber is preferably 0.1 to 2.5 parts by weight.
The latex composition of the present invention preferably has a pH of 8.5 to 13.0.

  Moreover, according to this invention, the film forming body which consists of said latex composition is provided.

  According to the present invention, it is possible to suppress the occurrence of symptoms of delayed type allergy (Type IV) in addition to immediate type allergy (Type I), and have high tensile strength and excellent durability. There can be provided a latex composition capable of providing a film molded body, and a film molded body using the latex composition.

  The latex composition of the present invention contains a carboxyl group-containing nitrile rubber latex and hypochlorite.

  The carboxyl group-containing nitrile rubber latex used in the present invention is a conjugated diene monomer, an ethylenically unsaturated nitrile monomer, an ethylenically unsaturated carboxylic acid monomer, and a copolymer with these used as necessary. It is a latex of nitrile rubber obtained by copolymerizing other possible ethylenically unsaturated monomers.

  Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and chloroprene. It is 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. The amount of the conjugated diene monomer used is preferably 30 to 89 parts by weight, more preferably 40 to 84 parts by weight, and still more preferably 50 to 78 parts by weight with respect to 100 parts by weight of the total monomers used for the polymerization. is there. The content ratio of the conjugated diene monomer unit in the carboxyl group-containing nitrile rubber is preferably 30 to 89% by weight, more preferably 40 to 84% by weight, and still more preferably 50 to 78% by weight. By making the amount of conjugated diene monomer used (content ratio of conjugated diene monomer unit) in the above range, the resulting dip-molded article should have a better texture and higher tensile strength. Can do.

  Examples of the ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile and the like. Of these, 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. The amount of the ethylenically unsaturated nitrile monomer used is preferably 10 to 50 parts by weight, more preferably 15 to 45 parts by weight, still more preferably 20 to 40 parts by weight based on 100 parts by weight of the total monomers used for the polymerization. Parts by weight. The content of the ethylenically unsaturated nitrile monomer unit in the carboxyl group-containing nitrile rubber is preferably 10 to 50% by weight, more preferably 15 to 45% by weight, and still more preferably 20 to 40% by weight. is there. By making the amount of the ethylenically unsaturated nitrile monomer used (content ratio of the ethylenically unsaturated nitrile monomer unit) in the above range, it is possible to obtain a film molded body such as a dip molded body having sufficient tensile strength. However, it can be made more excellent by texture and elongation.

  Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; ethylenically unsaturated polyvalent carboxylic acids such as itaconic acid, maleic acid and fumaric acid Monomers; ethylenically unsaturated polyvalent carboxylic acid partial ester monomers such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate; and other ethylenic monomers such as maleic anhydride and citraconic anhydride A monomer that generates a carboxyl group by hydrolysis of an unsaturated polycarboxylic acid anhydride, and the like. Among these, an ethylenically unsaturated monocarboxylic acid monomer is preferable, an ethylenically unsaturated monocarboxylic acid monomer having 3 to 10 carbon atoms is more preferable, and methacrylic acid is particularly preferable. These ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. The amount of the ethylenically unsaturated carboxylic acid monomer used is preferably from 1 to 20 parts by weight, more preferably from 1 to 15 parts by weight, and even more preferably from 2 to 100 parts by weight based on 100 parts by weight of the total monomers used for the polymerization. 10 parts by weight. The content of the ethylenically unsaturated carboxylic acid monomer unit in the carboxyl group-containing nitrile rubber is preferably 1 to 20% by weight, more preferably 1 to 15% by weight, and still more preferably 2 to 10% by weight. It is. By setting the amount of the ethylenically unsaturated carboxylic acid monomer used (content ratio of the ethylenically unsaturated carboxylic acid monomer unit) to the above range, it is possible to obtain a film molded body such as a dip molded body having a tensile strength. While being sufficient, it can be made more excellent in texture and elongation.

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

  The amount of other ethylenically unsaturated monomers that can be copolymerized is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and still more preferably 100 parts by weight of all monomers used for polymerization. 10 parts by weight or less. In addition, the content of other copolymerizable ethylenically unsaturated monomers in the carboxyl group-containing nitrile rubber is preferably 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less. It is. By setting the amount of other copolymerizable other ethylenically unsaturated monomers used (content ratio of other copolymerizable other ethylenically unsaturated monomers) within the above range, the resulting dip-molded product is more The texture can be excellent.

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

  When the monomer mixture containing the above-described monomer is subjected to emulsion polymerization, commonly used polymerization auxiliary materials such as an emulsifier, a polymerization initiator, and a molecular weight modifier can be used. The method for adding these polymerization auxiliary materials is not particularly limited, and any method such as an initial batch addition method, a divided addition method, or a continuous addition method may be used.

  Although it does not specifically limit as an emulsifier, For example, Nonionic emulsifiers, such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester; potassium dodecylbenzenesulfonate, dodecylbenzene Anionic emulsifiers such as alkyl benzene sulfonates such as sodium sulfonate, higher alcohol sulfates and alkyl sulfosuccinates; Cationic emulsifiers such as alkyltrimethylammonium chloride, dialkylammonium chloride and benzylammonium chloride; α, β-unsaturated Such as sulfo ester of carboxylic acid, sulfate ester of α, β-unsaturated carboxylic acid, sulfoalkyl aryl ether, etc. Or the like can be mentioned compatibility emulsifier. Among these, anionic emulsifiers are preferable, alkylbenzene sulfonates are more preferable, and potassium dodecylbenzenesulfonate and sodium dodecylbenzenesulfonate are particularly preferable. These emulsifiers can be used alone or in combination of two or more. The amount of the emulsifier used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer mixture.

The polymerization initiator is not particularly limited, and examples thereof include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, di-α- Organic peroxides such as cumyl peroxide, acetyl peroxide, isobutyryl peroxide, benzoyl peroxide; azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, methyl azobisisobutyrate; Can be mentioned. These polymerization initiators can be used alone or in combination of two or more.
The peroxide initiator is preferably used because it can stably produce a latex, and a dip-molded body having higher mechanical strength and softer texture can be obtained. The amount of the polymerization initiator used is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the monomer mixture.

  Further, the peroxide initiator can be used as a redox polymerization initiator in combination with a reducing agent. The reducing agent is not particularly limited, but is a compound containing a metal ion in a reduced state such as ferrous sulfate or cuprous naphthenate; a sulfonic acid compound such as sodium methanesulfonate; an amine compound such as dimethylaniline. And so on. These reducing agents can be used alone or in combination of two or more. The amount of the reducing agent used is preferably 3 to 1000 parts by weight with respect to 100 parts by weight of the peroxide.

  The amount of water used for emulsion polymerization is preferably 80 to 600 parts by weight, particularly preferably 100 to 200 parts by weight, based on 100 parts by weight of all monomers used.

  Examples of the monomer addition method include a method of adding monomers to be used in a reaction vessel all at once, a method of adding continuously or intermittently as the polymerization proceeds, and a part of the monomer is added. And a method in which the remaining monomer is continuously or intermittently added and polymerized, and any method may be employed. When the monomers are mixed and added continuously or intermittently, the composition of the mixture may be constant or may be changed. Each monomer may be added to the reaction vessel after previously mixing various monomers to be used, or may be added separately to the reaction vessel.

  Furthermore, polymerization auxiliary materials such as a chelating agent, a dispersant, a pH adjuster, a deoxidizing agent, and a particle size adjuster can be used as necessary, and these are not particularly limited in terms of type and amount used.

  Although the polymerization temperature at the time of performing emulsion polymerization is not specifically limited, Usually, it is 5-95 degreeC, Preferably it is 30-70 degreeC. The polymerization time is about 5 to 40 hours.

  As described above, the monomer mixture is subjected to emulsion polymerization, and when a predetermined polymerization conversion rate is reached, the polymerization reaction is stopped by cooling the polymerization system or adding a polymerization terminator. The polymerization conversion rate when stopping the polymerization reaction is preferably 90% by weight or more, more preferably 93% by weight or more.

  The polymerization terminator is not particularly limited. For example, hydroxylamine, hydroxyamine sulfate, diethylhydroxylamine, hydroxyaminesulfonic acid and its alkali metal salt, sodium dimethyldithiocarbamate, hydroquinone derivative, catechol derivative, and hydroxydimethyl Examples thereof include aromatic hydroxydithiocarboxylic acids such as benzenethiocarboxylic acid, hydroxydiethylbenzenedithiocarboxylic acid, hydroxydibutylbenzenedithiocarboxylic acid, and alkali metal salts thereof. The amount of the polymerization terminator used is preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the monomer mixture.

  After stopping the polymerization reaction, if desired, the unreacted monomer is removed, and the solid content concentration and pH are adjusted to obtain a carboxyl group-containing nitrile rubber latex.

  Moreover, you may add suitably an anti-aging agent, antiseptic | preservative, an antibacterial agent, a dispersing agent etc. to the latex of the carboxyl group-containing nitrile rubber used by this invention as needed.

  The solid content concentration of the carboxyl group-containing nitrile rubber latex used in the present invention is preferably 5 to 50% by weight, more preferably 10 to 45% by weight. By setting the solid content concentration within the above range, the viscosity of the latex becomes appropriate, and the latex can be transported through the piping and stirred in the preparation tank more easily. Thus, the film thickness of the obtained film molded body can be made moderate, and the tensile strength of the film molded body can be made higher.

  The number average particle size of the latex of the carboxyl group-containing nitrile rubber used in the present invention is not particularly limited, but is preferably 60 to 300 nm, more preferably 80 to 150 nm. The particle diameter can be adjusted to a desired value by a method such as adjusting the amount of emulsifier and polymerization initiator used.

Hypochlorite The latex composition of the present invention contains hypochlorite in addition to the latex of carboxyl group-containing nitrile rubber.

  The hypochlorite used in the present invention is capable of forming a crosslinked structure by reacting with the carboxyl group of the carboxyl group-containing nitrile rubber constituting the latex of the carboxyl group-containing nitrile rubber. By blending hypochlorite into the latex of carboxyl group-containing nitrile rubber, the molded film produced using the resulting latex composition may have high tensile strength and excellent durability. It becomes possible. According to the present invention, a vulcanization accelerator (for example, a dithiocarbamate-based vulcanization that causes generation of symptoms of delayed type allergy (Type IV), in particular, without using zinc oxide, sulfur, and a vulcanization accelerator. Film forming body obtained by forming a crosslinked structure using hypochlorite without using an accelerator, a thiazole vulcanization accelerator, etc., and producing a film forming body such as a dip-molded body With respect to the above, it is possible to suppress the occurrence of symptoms of delayed type allergy (Type IV) while ensuring sufficient tensile strength and durability. Moreover, since the latex composition of the present invention uses not a natural rubber but a carboxyl group-containing nitrile rubber which is a synthetic rubber, the obtained film molded product is an immediate type due to the protein contained in the natural rubber. The occurrence of allergy (Type I) symptoms can also be suppressed.

  Hypochlorite includes alkali metal salt or alkaline earth metal salt of hypochlorous acid, such as sodium hypochlorite, potassium hypochlorite, lithium hypochlorite, hypochlorous acid. Calcium, magnesium hypochlorite, barium hypochlorite and the like can be mentioned. Among these, sodium hypochlorite and potassium hypochlorite are preferable, and sodium hypochlorite is more preferable. These hypochlorites can be used alone or in combination of two or more.

  The content ratio of hypochlorite in the latex composition of the present invention is preferably 0.1 to 2.5 parts by weight, more preferably 100 parts by weight of carboxyl group-containing nitrile rubber contained in the latex. 0.5 to 2.0 parts by weight, more preferably 0.8 to 1.7 parts by weight. By setting the content ratio of hypochlorite within the above range, the tensile strength and durability of the film molded body such as dip molded body obtained can be reduced while suppressing the occurrence of delayed type allergy (Type IV) symptoms. It can be improved further.

  In the latex composition of the present invention, the method of blending hypochlorite may be any method as long as it finally results in a mixture of the carboxyl group-containing nitrile rubber latex and hypochlorite, and is particularly limited. However, for example, there may be mentioned a method of blending hypochlorite with the carboxyl group-containing nitrile rubber latex after obtaining the carboxyl group-containing nitrile rubber latex described above.

Latex Composition The latex composition of the present invention contains the carboxyl group-containing nitrile rubber latex and hypochlorite.

The latex composition of the present invention only needs to contain a carboxyl group-containing nitrile rubber latex and hypochlorite, but may further contain a sulfur-based vulcanizing agent.
Examples of sulfur-based vulcanizing agents include powder sulfur, sulfur white, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, and the like; sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, caprolactam disulfide (N , N′-dithio-bis (hexahydro-2H-azepinone-2)), phosphorus-containing polysulfides, polymer polysulfides, and sulfur-containing compounds such as 2- (4′-morpholinodithio) benzothiazole. Among these, sulfur can be preferably used. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

  Although content of a sulfur type vulcanizing agent is not specifically limited, Preferably it is 3.0 weight part or less with respect to 100 weight part of carboxyl group-containing nitrile rubber, More preferably, it is 1.5 weight part or less. By making the content of the sulfur-based vulcanizing agent in the above range, the tensile strength is further increased while suppressing the occurrence of symptoms of delayed type allergy (Type IV) in film molded products such as dip molded products. Can do.

Further, the latex composition of the present invention further contains a crosslinking accelerator as long as it is within a range that can suppress the occurrence of delayed type allergy (Type IV) in a film molded product such as a dip molded product. Also good.
As the crosslinking accelerator, those usually used in dip molding can be used. Acids and their zinc salts; 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2- (2,4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthio-carbylthio) benzothiazole, 2- (2,6-dimethyl-4-morpholinothio) benzothiazole, 2- (4'-morpholino-dithio) benzothia And 4-morpholinyl-2-benzothiazyl disulfide, 1,3-bis (2-benzothiazyl mercaptomethyl) urea, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc 2-mercaptobenzothiazole Is preferred. A crosslinking accelerator can be used individually by 1 type or in combination of 2 or more types.

  The latex composition of the present invention further includes a pH adjuster; an anti-aging agent; a dispersant; a reinforcing agent such as carbon black, silica and talc; a filler such as calcium carbonate and clay; an ultraviolet absorber; a plasticizer; These additives can be blended as necessary.

  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 bicarbonate; ammonia An organic amine compound such as trimethylamine or triethanolamine; an alkali metal hydroxide is preferred.

  Anti-aging agents include 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'-methylenebis (2,6-di-t-butylphenol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), alkylated bisphenol, p-cresol and dicyclopentadiene Phenol-based antioxidants containing no sulfur atom, such as reaction products; 2,2′-thiobis- (4-methyl-6-tert-butylphenol) ), 4,4′-thiobis- (6-tert-butyl-o-cresol), 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5- Thiobisphenol-based antioxidants such as triazin-2-ylamino) phenol; phosphite-based antioxidants such as tris (nonylphenyl) phosphite, diphenylisodecyl phosphite, tetraphenyldipropylene glycol diphosphite; thiodipropion Sulfur-based antioxidants such as dilauryl acid; 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 antioxidants such as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; -Hydroquinone anti-aging agents such as di- (t-amyl) hydroquinone; These anti-aging agents can be used alone or in combination of two or more.

  The content of the anti-aging agent is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the carboxyl group-containing nitrile rubber.

  The method of mixing various compounding agents with the latex composition of the present invention is not particularly limited. For example, as described above, a carboxyl group-containing nitrile rubber latex and a latex composition containing hypochlorite are used. After obtaining, using a dispersing machine such as a ball mill, a kneader, or a disper, a method of mixing various compounding agents blended into the latex composition as necessary, or using the above dispersing machine, a carboxyl group-containing nitrile Examples thereof include a method of preparing an aqueous dispersion of compounding ingredients other than rubber latex and then mixing the aqueous dispersion with a carboxyl group-containing nitrile rubber latex.

  In addition, pH of the latex composition of this invention becomes like this. Preferably it is 8.5-13.0, More preferably, it is 9.0-13.0, More preferably, it is 9.5-13.0. By setting the pH of the latex composition within the above range, the tensile strength and durability of the resulting dip-molded product can be further improved.

  In particular, since the pH of the latex composition can further improve the tensile strength and durability of the resulting dip-molded product, the ethylenic defect in the carboxyl group-containing nitrile rubber that constitutes the latex of the carboxyl group-containing nitrile rubber is determined. It is preferable to adjust appropriately according to the content rate of a saturated carboxylic acid monomer unit. For example, (1) when the content ratio of the ethylenically unsaturated carboxylic acid monomer unit in the carboxyl group-containing nitrile rubber is 2.0 to 4.5% by weight, the pH of the latex composition is 10.0. It is preferable to adjust to -13.0, and it is more preferable to adjust to 11.0-13.0. Further, (2) when the content ratio of the ethylenically unsaturated carboxylic acid monomer unit in the carboxyl group-containing nitrile rubber is 4.6 to 7.0% by weight, the pH of the latex composition is 9.0. It is preferable to adjust to -13.0, and it is more preferable to adjust to 10.0-12.5. Further, (3) when the content ratio of the ethylenically unsaturated carboxylic acid monomer unit in the carboxyl group-containing nitrile rubber is 7.1 to 10.0% by weight, the pH of the latex composition is set to 8.5. It is preferable to adjust to -11.0, and it is more preferable to adjust to 9.5-11.0.

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

When the latex composition of the present invention contains a sulfur-based vulcanizing agent, it is aged before being subjected to dip molding from the viewpoint of further improving mechanical properties of a film molded body such as a dip molded body to be obtained ( Precrosslinking is preferred. The time for precrosslinking is not particularly limited and depends on the temperature for precrosslinking, but is preferably 1 to 14 days, and more preferably 1 to 7 days. The pre-crosslinking temperature is preferably 20 to 40 ° C.
And after pre-crosslinking, it is preferable to store at a temperature of 10 to 30 ° C. until it is used for dip molding. When stored at a high temperature, the tensile strength of the obtained film molded body such as a dip molded body may be lowered.

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

  Although it does not specifically limit as a film molded object of this invention, It is suitable that it is a dip molded object obtained by dip-molding the latex composition of this invention. Dip molding is a method in which a mold is immersed in a latex composition, the composition is deposited on the surface of the mold, the mold is then lifted from the composition, and then the composition deposited on the mold surface is dried. is there. The mold before being immersed in the latex composition may be preheated. Further, a coagulant can be used as necessary before the mold is immersed in the latex composition or after the mold is pulled up from the latex composition.

  Specific examples of the method of using the coagulant include a method in which the mold before dipping in the latex composition is immersed in a solution of the coagulant to attach the coagulant to the mold (anode coagulation dipping method), and the latex composition is deposited. There is a method of immersing the formed mold in a coagulant solution (Teag adhesion dipping method), etc., but the anode adhesion dipping method is preferable in that a dip-formed product with little thickness unevenness can be obtained.

  Specific examples of coagulants 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 sulfates such as aluminum sulfate; Of these, calcium salts are preferable, and calcium nitrate is more preferable. These water-soluble polyvalent metal salts can be used alone or in combination of two or more.

  The coagulant can usually be used as a solution of water, alcohol, or a mixture thereof, and is preferably used in the form of 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 the mold is lifted from the latex composition, the deposit formed on the mold is usually dried by heating. What is necessary is just to select drying conditions suitably.

  When the latex composition contains a crosslinking agent, the obtained dip-molded layer is usually subjected to a heat treatment for crosslinking. Before the heat treatment, water-soluble impurities (for example, excess emulsifier and coagulant) may be removed by immersing in water, preferably 30 to 70 ° C. for about 1 to 60 minutes. The operation for removing the water-soluble impurities may be performed after the dip-molded layer is heat-treated, but it is preferably performed before the heat-treatment because the water-soluble impurities can be more efficiently removed.

  The crosslinking of the dip-molded layer (that is, the formation of a crosslinked structure by the reaction between the carboxyl group of the carboxyl group-containing nitrile rubber and hypochlorite) is performed at a temperature of preferably 100 to 140 ° C, more preferably 110 to 130 ° C. The heating time is preferably 5 to 80 minutes, more preferably 10 to 40 minutes. As a heating method, an external heating method using infrared rays or heated air or an internal heating method using high frequency can be employed. Of these, external heating with heated air is preferred.

Then, by removing the dip molding layer from the dip molding die, the dip molded body is obtained as a film-like film molded body. As the desorption method, it is possible to adopt a method of peeling from the mold by hand, or peeling by water pressure or compressed air pressure. In addition, after desorption, you may heat-process for 10 to 120 minutes at the temperature of 60-120 degreeC.
In addition to the method of dip-molding the latex composition of the present invention described above, the film molded body of the present invention is a method that can form the latex composition of the present invention into a film (for example, a coating method, etc.). ) As long as it is obtained by any method.

  Since the film molded body of the present invention including the dip molded body of the present invention is obtained by using the above-described latex composition of the present invention, it has high tensile strength and excellent durability. Can be used particularly preferably. When the film molded body is a glove, in order to prevent adhesion between the contact surfaces of the film molded bodies and improve slippage during attachment and detachment, organic fine particles such as inorganic fine particles such as talc and calcium carbonate or starch particles are gloved. It may be dispersed 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 membrane molded body of the present invention including the dip molded body of the present invention is a medical article such as a baby bottle nipple, a dropper, a tube, a water pillow, a balloon sack, a catheter, and a condom; It can also be used for toys such as balls, industrial articles such as pressure forming bags and gas storage bags, and finger sack.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. The following “parts” are based on weight unless otherwise specified. Various physical properties were measured as follows.

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

Content ratio measurement of 1,3 -butadiene units The content ratio of 1,3-butadiene units was calculated by measuring the iodine value (according to JIS K 6235) of the conjugated diene copolymer.

Content ratio measurement of acrylonitrile unit The content ratio of the acrylonitrile unit was calculated by measuring the nitrogen content in the conjugated diene copolymer by Kjeldahl method according to JIS K6384.

Measurement of content ratio of methacrylic acid unit To 0.2 g of a 2 mm square conjugated diene copolymer, 100 ml of 2-butanone was added and stirred for 16 hours. Then, 20 ml of ethanol and 10 ml of water were added, and while stirring, 0 ml of potassium hydroxide was added. Using a 0.02N aqueous ethanol solution, titration with thymolphthalein as an indicator at room temperature was performed to obtain the number of moles of carboxyl groups relative to 100 g of the conjugated diene copolymer (unit: ephr). By converting to the amount of methacrylic acid units, the content ratio of methacrylic acid units in the conjugated diene copolymer was calculated.

Tensile strength of dip-molded body Based on ASTM D412, a film-shaped dip-molded body having a film thickness of about 0.2 mm is punched with a dumbbell (trade name “Super Dumbbell (model: SDMK-100C)”, manufactured by Dumbbell) A test piece for measuring tensile strength was prepared. The test piece was pulled at a tensile speed of 500 mm / min with a Tensilon universal testing machine (trade name “RTG-1210”, manufactured by Orientec Corp.), and the tensile strength (unit: MPa) immediately before breaking was measured.

Ten test subjects wore the dip-molded body (rubber gloves) obtained for the wearing durability time , and the keyboard input operation was lightly performed. Every time 10 minutes have passed since the work was started, the crotch portion of the finger of the rubber glove was observed to confirm the presence or absence of microcracks. In each test, after measuring the time until a microcrack occurred in a rubber glove, the wearing endurance time was obtained by arithmetically averaging 8 data (data of 8 people) excluding the shortest and longest time. The evaluation of the wearing durability time was up to 240 minutes. It can be determined that the longer the wearing durability time is, the better the dip molded body is.

A test piece obtained by cutting the dip-molded body obtained by the patch test into a size of 10 × 10 mm was attached to the arms of 10 subjects. Thereafter, the presence of allergic symptoms of immediate type allergy (Type I) was confirmed by observing the applied part 180 minutes later, and further, 48 hours later, the applied part was observed to observe delayed type allergy (Type IV). The presence or absence of allergic symptoms was confirmed and evaluated according to the following criteria.
○: For all subjects, no allergic symptoms were observed at 180 minutes and 48 hours after application.
X: For all subjects, no allergic symptoms were observed 180 minutes after application, but for some subjects, allergic symptoms were observed 48 hours after application.

Production Example 1
Production of latex of carboxyl group-containing nitrile rubber (A-1) In a pressure-resistant polymerization reactor, 27.0 parts of acrylonitrile, 5.5 parts of methacrylic acid, 0.5 part of t-dodecyl mercaptan as a molecular weight regulator, deionized water 150 1 part, 2.5 parts of sodium dodecylbenzenesulfonate were charged, and after replacing the internal gas with nitrogen three times, 67.5 parts of 1,3-butadiene were charged. Next, 0.2 part of potassium persulfate and 0.1 part of sodium ethylenediaminetetraacetate were charged, and then the polymerization temperature was set to 39 ° C. to initiate the polymerization reaction. The polymerization reaction was continued until the polymerization conversion reached 97%, and then 0.1 part of diethylhydroxylamine was added to stop the polymerization reaction. After the unreacted monomer was distilled off under reduced pressure from the obtained copolymer latex, the solid content concentration and pH were adjusted, and the carboxyl group-containing nitrile rubber having a solid content concentration of 45% and a pH of 8.5 ( A latex of A-1) was obtained. The carboxyl group-containing nitrile rubber (A-1) contained in the obtained latex was measured for the content of 1,3-butadiene units, acrylonitrile units, and methacrylic acid units according to the above method. The content ratio of the body unit was almost the same as the amount of each monomer used (the amount charged in the pressure-resistant polymerization reactor) (carboxyl group-containing nitrile rubber (A-2) in Production Example 2 described later), production The same applies to the carboxyl group-containing nitrile rubber (A-3) of Example 3 and the nitrile rubber (A'-4) of Production Example 4.)

Production Example 2
Production of latex of carboxyl group-containing nitrile rubber (A-2) The amount of acrylonitrile used is changed from 27.0 parts to 22.0 parts, the amount of methacrylic acid used is changed from 5.5 parts to 4.0 parts, -Carboxyl group-containing nitrile rubber (A-2) having a solid content concentration of 45% and a pH of 8.5 in the same manner as in Production Example 1, except that the amount of butadiene used was changed from 67.5 parts to 74.0 parts, respectively. Latex was obtained.

Production Example 3
Production of latex of carboxyl group-containing nitrile rubber (A-3) The amount of acrylonitrile used is changed from 27.0 parts to 31.0 parts, the amount of methacrylic acid used is changed from 5.5 parts to 8.0 parts, -A carboxyl group-containing nitrile rubber (A-3) having a solid content concentration of 45% and a pH of 8.5 in the same manner as in Production Example 1 except that the amount of butadiene used was changed from 67.5 parts to 61.0 parts. Latex was obtained.

Production Example 4
Production of latex of nitrile rubber (A'-4) The amount of acrylonitrile used was changed from 27.0 parts to 40.0 parts, and the amount of 1,3-butadiene used was changed from 67.5 parts to 60.0 parts. A latex of nitrile rubber (A′-4) having a solid concentration of 45% and a pH of 8.5 was obtained in the same manner as in Production Example 1 except that methacrylic acid was not used.

Production Example 5
Production of latex of carboxy-modified synthetic polyisoprene (A′-5) Synthetic polyisoprene having a weight average molecular weight of 1,300,000 (trade name “NIPOL IR2200L”, manufactured by Nippon Zeon Co., Ltd., isoprene homopolymer, cis bond (Unit amount 98%) is mixed with cyclohexane, the temperature is raised to 60 ° C. with stirring, the solution is dissolved, and the cyclohexane solution of synthetic polyisoprene having a viscosity of 12,000 mPa · s measured with a B-type viscometer Was adjusted (solid content concentration 8 wt%).

  On the other hand, 20 parts of sodium rosinate was added to water, and the temperature was raised to 60 ° C. to dissolve, thereby preparing 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) are mixed with a mixer (trade name “Multiline Mixer MS26-MMR-5” so that the weight ratio is 1: 1.5. .5L ", manufactured by Satake Chemical Machinery Co., Ltd.), followed by mixing and emulsification using an emulsifying device (trade name" Milder MDN310 ", manufactured by Taiheiyo Kiko Co., Ltd.) at a rotational speed of 4100 rpm. A liquid (c) was obtained. At that time, the total feed flow rate of the 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 0.5 MPa.

  Next, the emulsion (c) is heated to 80 ° C. under a 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 in an amount of 300 ppm by weight with respect to the synthetic polyisoprene in the emulsion (c). . When distilling off cyclohexane, the emulsified liquid (c) is adjusted to 70% by volume or less of the tank volume, and a three-stage inclined paddle blade is used as a stirring blade, and the stirring is slowly performed at 60 rpm. Carried out.

  And after the distillation of cyclohexane was completed, the obtained synthetic polyisoprene aqueous dispersion (d) was 4,000 to 4,000 using a continuous centrifuge (trade name “SRG510”, manufactured by Alfa Laval). Centrifugation was performed at 5,000 G to obtain a latex (e) of synthetic polyisoprene having a solid concentration of 56% by weight as a light liquid. The conditions of the centrifugation were as follows: the solid content concentration of the aqueous dispersion (d) before centrifugation was 10% by weight, the flow rate during continuous centrifugation was 1300 kg / hr, and the back pressure (gauge pressure) of the centrifuge was 1. The pressure was 5 MPa. The obtained synthetic polyisoprene latex (e) had a solid content of 60% by weight.

  Next, 850 parts of distilled water was added to the synthetic polyisoprene latex (e) in the resulting synthetic polyisoprene latex (e) to dilute it. The diluted latex was charged into a nitrogen-substituted polymerization reactor equipped with a stirrer, and the temperature was raised to 30 ° C. while stirring. Further, using another container, 5.0 parts of methacrylic acid and 16 parts of distilled water were mixed to prepare a methacrylic acid diluted solution. This diluted methacrylic acid solution was added to the polymerization reaction vessel 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 Company), ferrous sulfate (trade name “Frost Fe”, Chubu Kirestu) A solution (f) consisting of 0.01 part) 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 reacted at 70 ° C. for 2 hours, whereby methacrylic acid was graft-polymerized on the synthetic polyisoprene. The conversion of graft polymerization was 99% by weight.

  Next, sodium hydroxide was added to adjust the pH to 10, and 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, the back pressure (gauge pressure) of the centrifuge was 0.08 MPa), and a latex of carboxy-modified synthetic polyisoprene (A′-5) having a solid content concentration of 55% by weight was obtained. The ratio of the carboxy modification to the synthetic polyisoprene in the carboxy-modified synthetic polyisoprene (A′-5) contained in the obtained latex was 1.7 parts.

Example 1
Preparation of latex composition To 222.2 parts of latex of carboxyl group-containing nitrile rubber (A-1) obtained in Production Example 1 (100 parts in terms of carboxyl group-containing nitrile rubber (A-1)), in terms of solid content Dip-forming composition (solid content concentration adjusted to pH 12.0 by adding an aqueous solution of each compounding agent so that 0.8 parts of sodium hypochlorite and 2.3 parts of potassium hydroxide were obtained. : 19% by weight). And about the obtained latex composition, it age | cure | ripened for 48 hours in the constant temperature water tank adjusted to 30 degreeC.

Production of Dip Molded Body After washing a commercially available ceramic hand mold (manufactured by Shinko), preheating in an oven at 70 ° C., 18 wt% calcium nitrate and 0.05 wt% polyoxyethylene lauryl ether ( It was immersed for 5 seconds in a coagulant aqueous solution containing the 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 attach a coagulant to the hand mold, and the hand mold was coated with the coagulant.

  Thereafter, the hand mold coated with the coagulant was taken out of the oven and immersed in the latex composition after aging described above for 10 seconds. 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 water-soluble impurities, thereby forming a dip-molded layer on the hand mold. After that, the dip-formed layer formed on the hand mold was crosslinked by heating in an oven at a temperature of 130 ° C. for 30 minutes, cooled to room temperature, sprinkled with talc, and then peeled off from the hand mold. A dip-molded body (rubber gloves) was obtained. And about each of the obtained dip molding (rubber glove), according to the said method, each evaluation of tensile strength and wearing durability time was performed. The results are shown in Table 1.

Example 2
When preparing the latex composition, the amount of sodium hypochlorite was changed from 0.8 parts to 1.5 parts, except that 0.7 parts of sodium hydroxide was used instead of potassium hydroxide, In the same manner as in Example 1, a latex composition having a pH of 10.0 and a dip-formed product (rubber glove) were produced and evaluated in the same manner. The results are shown in Table 1.

Example 3
When preparing the latex composition, the amount of sodium hypochlorite was changed from 0.8 parts to 1.5 parts, and the amount of potassium hydroxide was changed from 2.3 parts to 2.0 parts, respectively. Produced a latex composition having a pH of 12.0 and a dip-formed product (rubber glove) in the same manner as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

Example 4
When preparing the latex composition, the amount of sodium hypochlorite was changed from 0.8 parts to 1.5 parts, and the amount of potassium hydroxide was changed from 2.3 parts to 2.5 parts. Produced a latex composition having a pH of 12.5 and a dip-molded body (rubber glove) in the same manner as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

Example 5
When preparing the latex composition, the amount of sodium hypochlorite was changed from 0.8 parts to 1.5 parts, and 1.8 parts of sodium hydroxide was used instead of potassium hydroxide, In the same manner as in Example 1, a latex composition having a pH of 12.5 and a dip-formed product (rubber glove) were produced and evaluated in the same manner. The results are shown in Table 1.

Example 6
When preparing the latex composition, instead of the latex of the carboxyl group-containing nitrile rubber (A-1) obtained in Production Example 1, the carboxyl group-containing nitrile rubber (A-2) obtained in Production Example 2 was used. Latex (100 parts in terms of carboxyl group-containing nitrile rubber (A-2)) is used, and further, the amount of sodium hypochlorite is changed from 0.8 part to 1.5 parts, and the amount of potassium hydroxide is changed. A latex composition having a pH of 11.0 and a dip-molded body (rubber glove) were produced in the same manner as in Example 1 except that the amount was changed from 2.3 parts to 1.5 parts, and evaluated in the same manner. . The results are shown in Table 1.

Example 7
A latex composition having a pH of 12.0 and dip molding were prepared in the same manner as in Example 6 except that the amount of potassium hydroxide was changed from 1.5 parts to 2.0 parts when preparing the latex composition. A body (rubber gloves) was produced and evaluated in the same manner. The results are shown in Table 1.

Example 8
A latex composition having a pH of 13.0 and a dip molded article (rubber) were prepared in the same manner as in Example 6 except that 2.0 parts of sodium hydroxide was used instead of potassium hydroxide when preparing the latex composition. Gloves) were manufactured and evaluated in the same manner. The results are shown in Table 1.

Example 9
When preparing the latex composition, instead of the latex of the carboxyl group-containing nitrile rubber (A-1) obtained in Production Example 1, the carboxyl group-containing nitrile rubber (A-3) obtained in Production Example 3 was used. Use latex (100 parts in terms of carboxyl group-containing nitrile rubber (A-3)), change the amount of sodium hypochlorite from 0.8 parts to 1.0 part, and mix potassium hydroxide A latex composition having a pH of 9.5 and a dip-molded body (rubber glove) were produced in the same manner as in Example 1 except that the evaluation was not performed. The results are shown in Table 1.

Example 10
A latex composition having a pH of 10.0 was prepared in the same manner as in Example 9 except that the amount of sodium hypochlorite was changed from 1.0 part to 1.5 parts when preparing the latex composition, and A dip-molded body (rubber glove) was produced and evaluated in the same manner. The results are shown in Table 1.

Example 11
When preparing the latex composition, the amount of sodium hypochlorite was changed from 1.0 part to 1.7 parts and, further, 1.7 parts of potassium hydroxide was added, and Example 9 and Similarly, a latex composition having a pH of 11.0 and a dip-formed product (rubber glove) were produced and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 1
In preparing the latex composition, instead of sodium hypochlorite, 1.0 part of colloidal sulfur, 0.5 part of zinc dibutyldithiocarbamate, and 1.5 parts of zinc oxide were used, and potassium hydroxide was added. A latex composition having a pH of 10.0 and a dip-molded body (rubber gloves) were produced in the same manner as in Example 1 except that the amount was changed from 2.3 parts to 1.3 parts. It was. The results are shown in Table 1.

Comparative Example 2
When preparing the latex composition, pH 12 was added in the same manner as in Example 1 except that sodium hypochlorite was not added and the amount of potassium hydroxide was changed from 2.3 parts to 3.0 parts. 0.0 latex composition and a dip-molded body (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, instead of the carboxyl group-containing nitrile rubber (A-1) latex obtained in Production Example 1, the latex of nitrile rubber (A′-4) obtained in Production Example 4 ( Nitrile rubber (100 parts in terms of A'-4) is used, the sodium hypochlorite content is changed from 0.8 parts to 1.5 parts, and the potassium hydroxide content is 2.3 parts. A latex composition having a pH of 12.0 and a dip-formed product (rubber glove) were produced in the same manner as in Example 1 except that the content was changed from 0.2 to 0.2 part, and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 4
When preparing the latex composition, the carboxy-modified synthetic polyisoprene (A′-5) obtained in Production Example 5 was used instead of the latex of the carboxyl group-containing nitrile rubber (A-1) obtained in Production Example 1. Of latex (100 parts in terms of carboxy-modified synthetic polyisoprene (A′-5)), and the amount of sodium hypochlorite was changed from 0.8 part to 1.0 part, A latex composition having a pH of 12.0 and a dip-formed product (rubber glove) were produced in the same manner as in Example 1 except that was not blended and evaluated in the same manner. The results are shown in Table 1.

  From Table 1, the dip-molded body manufactured using a latex composition containing a carboxyl group-containing nitrile rubber latex and hypochlorite is excellent in tensile strength and has a long wearing durability. It was also excellent in properties (Examples 1 to 11). Furthermore, since the latex compositions of Examples 1 to 11 do not contain a vulcanization accelerator that causes the symptoms of delayed type allergy (Type IV), they are produced using the latex compositions of Examples 1 to 11. The formed dip-molded product is considered to be able to satisfactorily suppress the occurrence of symptoms of delayed type allergy (Type IV).

On the other hand, when a latex composition obtained by blending colloidal sulfur and zinc dibutyldithiocarbamate instead of hypochlorite is used, the produced dip-molded product has a tensile strength and a mounting durability of Although it is good, since it contains zinc dibutyldithiocarbamate, which is a vulcanization accelerator, it is considered to cause symptoms of delayed type allergy (Type IV) (Comparative Example 1).
In addition, when a latex composition that does not contain hypochlorite and does not contain colloidal sulfur and zinc dibutyldithiocarbamate is used, the manufactured dip-molded product has a short wearing durability. The durability was inferior (Comparative Example 2).
In addition, when using a latex composition obtained by using a nitrile rubber that does not contain a carboxyl group, the produced dip-molded product has low tensile strength and has a short wearing endurance. It was also inferior in property (Comparative Example 3).
In addition, when using a latex composition obtained by using polyisoprene instead of nitrile rubber even if it contains a carboxyl group, the produced dip-molded product has low tensile strength and is attached. Since the durability time was short, it was inferior in wearing durability (Comparative Example 4).

Claims (4)

  A latex composition comprising a latex of carboxyl group-containing nitrile rubber and hypochlorite.   The latex composition according to claim 1, wherein a content ratio of the hypochlorite with respect to 100 parts by weight of the carboxyl group-containing nitrile rubber is 0.1 to 2.5 parts by weight.   The latex composition according to claim 1 or 2, having a pH of 8.5 to 13.0.   The film molded object which consists of a latex composition in any one of Claims 1-3.