JP2003246891A - Composition for dip forming, and dip-formed article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dip-formed article which is excellent in hand and tensile strength and hardly discolors even when it is repeatedly worn, and a composition for dip forming, suitable for the dip-formed article. <P>SOLUTION: The composition for dip forming is characterized by comprising a copolymer latex of a specified composition, sulfur, and a vulcanization accelerator that contains or does not contain a dithiocarbamic acid derivative and its salt, wherein the content of a dithiocarbamic acid derivative and its salt is 0.2 pts.wt. or lower based on 100 pts.wt. solids of the copolymer latex. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dip-molding composition and a dip-molded product, and more particularly to a dip-molded product excellent in texture and tensile strength and resistant to discoloration even after repeated wearing, and the dip-molded product. The present invention relates to a dip molding composition suitable for products.

[0002]

2. Description of the Related Art Rubber gloves are widely used for domestic purposes, various industrial purposes such as the food industry and electronic parts manufacturing industry, and medical purposes. Rubber gloves should be stretched with a smaller force according to the movement of your fingers (the texture should be good) so that your hands do not get tired even if you wear them for a long time. It is required that it should not be torn and that it should not discolor after repeated wearing.

Conventionally, a rubber glove having high tensile strength and excellent oil resistance is obtained by dip-molding a dip-forming composition in which a carboxy-modified acrylonitrile-butadiene copolymer latex is mixed with sulfur and a vulcanization accelerator. Many things are used. For example, US Pat.
No. 4,362, a dip containing 100 parts by weight of carboxy-modified nitrile-butadiene rubber latex solids, 0.5 parts by weight of zinc oxide, 1 part by weight of sulfur and 1 part by weight of zinc dibutyldithiocarbamate as a vulcanization accelerator. Rubber gloves dip-molded from a molding composition are disclosed. However, although such gloves have excellent texture, they have insufficient tensile strength and may be broken during wearing, and the gloves are discolored when repeatedly worn.

Further, International Publication WO 97/48765 discloses that carboxy-modified acrylonitrile-butadiene copolymer latex solid content 1 without containing zinc oxide.
A glove that is dip molded from a dip molding composition containing 00 parts by weight, 1 part by weight sulfur, and 0.5 parts by weight zinc dibutylcarbamate as a vulcanization accelerator is disclosed. Such gloves have high tensile strength and are less likely to be torn during wearing, but have insufficient texture, and the gloves are discolored when repeatedly worn.

Further, in the publication of WO00 / 21451, 100% solid content of latex of acrylonitrile-butadiene copolymer containing a specific amount of carboxyl group.
Dip from a dip molding composition containing 1 part by weight, 0.2 to 0.3 parts by weight of zinc oxide, 2 parts by weight of sulfur and 0.35 to 0.75 parts by weight of a zinc salt of a carbamic acid derivative as a vulcanization accelerator. Molded rubber gloves are disclosed. Such gloves have a poor balance of texture and tensile strength, and the gloves discolor when worn repeatedly.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a dip-molded article which is excellent in texture and tensile strength and hardly discolored even after repeated wear, and a dip-molded article suitable for the dip-molded article. The present invention provides a composition for use.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies to overcome the problems of the prior art, the inventors of the present invention have found that a carboxy-modified acrylonitrile-butadiene copolymer latex having a specific composition is used for vulcanization. It has been found that the above object can be achieved by using a dip molding composition in which the amount of a salt of a dithiocarbamic acid derivative which is widely used as an accelerator is suppressed to a specific amount or less, and the present invention is based on this finding. Has been completed.

Thus, according to the present invention, conjugated diene monomer 50-84% by weight, ethylenically unsaturated nitrile monomer 15-40% by weight, ethylenically unsaturated acid monomer 1-1.
Copolymer latex obtained by polymerizing a monomer mixture consisting of 0% by weight and 0 to 20% by weight of another ethylenically unsaturated monomer copolymerizable therewith, sulfur, and dithiocarbamic acid derivative and the same. A dip molding composition comprising a vulcanization accelerator with or without salt, wherein the content of the dithiocarbamic acid derivative and its salt is 0.2 per 100 parts by weight of the solid content of the copolymer latex. There is provided a dip-forming composition, characterized in that it is contained in an amount of not more than 1 part by weight.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The copolymer latex used in the present invention comprises 50 to 84% by weight of a conjugated diene monomer, 15 to 40% by weight of an ethylenically unsaturated nitrile monomer, and 1 to 10 of an ethylenically unsaturated acid monomer.
It is obtained by polymerizing a monomer mixture consisting of 0 to 20% by weight and other ethylenically unsaturated monomers copolymerizable with these monomers.

The conjugated diene monomer is not particularly limited, and for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3. -Pentadiene, chloroprene, etc. can be mentioned. Of these, 1,3-butadiene is 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 50 to 84% by weight, preferably 5
It is 4 to 82% by weight, more preferably 58 to 78% by weight. When this amount is small, the texture is poor, and when it is large, the tensile strength is poor.

The ethylenically unsaturated nitrile monomer is not particularly limited, and examples thereof include acrylonitrile, methacrylonitrile, fumaronitrile and α-chloroacrylonitrile. Of these, acrylonitrile is preferred. These ethylenically unsaturated nitrile monomers can be used alone or in combination of two or more kinds.
The amount of the ethylenically unsaturated nitrile monomer used is 15 to 40% by weight, preferably 17 to 38% by weight, more preferably 20 to 36% by weight, based on the total monomers. When this amount is small, the tensile strength is poor, and when it is large, the texture is poor.

The ethylenically unsaturated acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing an acidic group such as a carboxyl group, a sulfonic acid group and an acid anhydride group, and examples thereof include acrylic acid. , Ethylenically unsaturated carboxylic acid monomers such as methacrylic acid, itaconic acid, maleic acid and fumaric acid;
Acid anhydrides such as maleic anhydride and citraconic anhydride; ethylenically unsaturated sulfonic acid monomers such as styrene sulfonic acid; monobutyl fumarate, monobutyl maleate, mono-2-hydroxypropyl maleate, etc. Carboxylic acid partial ester; and the like. These ethylenically unsaturated acid monomers can also be used as alkali metal salts or ammonium salts. Among these, ethylenically unsaturated carboxylic acid is preferable, and methacrylic acid is more preferable. These ethylenically unsaturated acid monomers may be used alone or in combination of two or more.

The amount of the ethylenically unsaturated acid monomer used is 1 to 10% by weight, preferably 1 to 8% by weight, more preferably 2 to 6% by weight, based on the total monomers. If this amount is small,
Inferior in tensile strength, and conversely, in a large amount, inferior in texture.

Other ethylenically unsaturated monomers copolymerizable with the above monomers include, for example, vinyl aromatic monomers such as styrene and alkylstyrene; (meth) acrylamide, N-methylol (meth). ) Ethylenically unsaturated amide monomers such as acrylamide; ethylenically unsaturated carboxylic acids such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate Acid ester monomers; crosslinkable monomers such as divinylbenzene, diethylene glycol di (meth) acrylate, pentaerythritol (meth) acrylate; and the like. The amount of the other ethylenically unsaturated monomer used is 0 to 20% by weight, preferably 10% by weight or less, and more preferably 5% by weight or less. If this amount is large, the balance between the texture and the tensile strength may deteriorate.

The above-mentioned copolymer latex can be usually produced by an emulsion polymerization method. As the emulsion polymerization method, a known method may be adopted, and for example, a method of polymerizing the monomer mixture using a polymerization initiator in the presence of an emulsifier in water can be adopted.

Examples of the emulsifier include nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester; myristic acid, palmitic acid, oleic acid, and linolene. Anionic emulsifiers such as salts of fatty acids such as acids, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, higher alcohol sulfate ester salts, alkyl sulfosuccinates; cations such as alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, benzyl ammonium chloride Emulsifier; α, β-unsaturated carboxylic acid sulfoester, α, β-unsaturated carboxylic acid sulfate ester, sulfoalkyl , And the like copolymerizable emulsifiers such as reel ether. Among them, anionic emulsifiers are preferably used. These emulsifiers can be used alone or in combination of two or more kinds. The amount of the emulsifier used is about 1 to 10 parts by weight, and more preferably 2 to 6 parts by weight, based on 100 parts by weight of the monomer mixture.

Examples of the polymerization initiator include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate and hydrogen peroxide; diisopropylbenzene hydroperoxide, cumene hydroperoxide and t-. Butyl hydroperoxide,
1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, di-α-cumyl peroxide, acetyl peroxide Examples thereof include organic peroxides such as isobutyryl peroxide and benzoyl peroxide; and azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile and methyl azobisisobutyrate. In particular, when an inorganic peroxide is used, a latex can be stably produced. These polymerization initiators can be used alone or in combination of two or more kinds. Although the amount of the polymerization initiator used varies slightly depending on the type, it is about 0.01 to 1 part by weight based on 100 parts by weight of the monomer mixture.

Further, peroxide can be used as a redox type polymerization initiator in combination with a reducing agent. Examples of the reducing agent include 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 compound such as dimethylaniline; Can be mentioned. These reducing agents can be used alone or in combination of two or more. The amount of the reducing agent used varies slightly depending on the kind of the reducing agent, but is about 0.03 to 10 parts by weight with respect to 1 part by weight of the peroxide.

In carrying out emulsion polymerization, it is preferable to use a molecular weight modifier in order to adjust the molecular weight of the copolymer. As a specific example of this, n-butyl mercaptan, t
-Mercaptans such as dodecyl mercaptan, sulfides such as tetraethyl thiuram sulfide, dibentamethylene thiuram hexasulfide, α-methylstyrene dimer, carbon tetrachloride and the like. Among them, mercaptans are preferable, and t-dodecyl mercaptan is more preferable. These can be used alone or in combination of two or more. The amount of the molecular weight modifier used is
The molecular weight of the copolymer may be appropriately determined so as to fall within a desired range, but is preferably 0.1 to 2 parts by weight, more preferably 0.3 to 1 part by weight, relative to 100 parts by weight of the monomer mixture. Is.

The amount of water used for emulsion polymerization is about 80 to 600 parts by weight, preferably 100 to 200 parts by weight, based on 100 parts by weight of the monomer mixture.

Further, if necessary, a polymerization auxiliary material such as a particle size adjusting agent, a chelating agent, an oxygen scavenger and a dispersant can be used.

The method of adding the monomer mixture is not particularly limited, and a method of charging the monomer mixture into the polymerization reactor all at once,
Any one of a method of continuously supplying the monomer mixture to the polymerization reactor, a method of charging a part of the monomer mixture to the polymerization reactor and continuously supplying the remaining monomer to the polymerization reactor, etc. May be adopted.

The polymerization temperature is preferably 5 to 60 ° C., more preferably 30 to 45 ° C., and the polymerization time is about 5 to 30 hours. The polymerization conversion rate when terminating the polymerization is preferably 90% by weight or more, more preferably 92% by weight or more.

The copolymer latex is emulsion-polymerized to a predetermined polymerization conversion rate, and if desired, a polymerization terminator is added to stop the reaction. Further, if desired, residual monomers are removed to obtain a predetermined solid content concentration. And the latex pH. Further, if desired, auxiliary materials such as an antiaging agent, an ultraviolet absorber, an antiseptic agent and an antibacterial agent can be added.

To adjust the pH of the copolymer latex, a basic substance is added. As this basic substance,
For example, 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; trimethyl ammonium, triethanol Organic amine compounds such as amines may be mentioned. Among them, alkali metal hydroxide or ammonia is preferably used. These basic substances are added in an amount of 1 to 4 in order to prevent the generation of aggregates when added.
It is added in the form of a solution having a concentration of 0% by weight, preferably 2 to 15% by weight, preferably an aqueous solution.

The particle size of the copolymer latex is preferably a number average particle size measured by a transmission electron microscope of 60 to 60.
It is 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.

The dip molding composition of the present invention is a dip molding composition comprising the above-mentioned copolymer latex, sulfur, and a vulcanization accelerator with or without the dithiocarbamic acid derivative and its salt. hand,
The content of the dithiocarbamic acid derivative and its salt is 0.2 with respect to 100 parts by weight of the solid content of the copolymer latex.
It is characterized by being less than or equal to parts by weight.

The amount of sulfur used is 1 to 8 parts by weight, preferably 2 to 6 parts by weight, more preferably 2 to 5 parts by weight, based on 100 parts by weight of the solid content of the copolymer latex. When the amount used is in this range, the balance between tensile strength and texture is excellent.

Examples of the vulcanization accelerator include aldehyde-amine condensates such as n-butyraldehyde-aniline condensate and butyraldehyde-monobutylamine condensate;
Thiazoles such as 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc salt, 2-mercaptobenzothiazole-cyclohexylamine salt and dibenzothiazyl disulfide; thiuram such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide and tetraethylthiuram disulfide. And the like; Among them, thiazoles are preferable, and 2-mercaptobenzothiazole zinc salt is more preferable. The amount of the vulcanization accelerator used is 0.3 to 5 parts by weight, preferably 0.5 to 4 parts by weight, based on 100 parts by weight of the solid content of the copolymer latex.
Parts by weight, more preferably 1 to 3 parts by weight. When the amount used is in this range, the balance between tensile strength and texture is excellent.

In the dip molding composition of the present invention, the content of the dithiocarbamic acid derivative and its salt is set to 100 parts by weight of the solid content of the copolymer latex.
It is an essential condition that the amount is 0.2 parts by weight or less. The dithiocarbamic acid derivative is a compound represented by the following formula (1), and its salt is a compound represented by the following formula (2). These compounds, especially the zinc salt in the following formula (2),
It is widely used as a vulcanization accelerator in latex dip molding.

[0031]

[Formula 1] (R _1, R ₂ are each independently a hydrocarbon group having a hydrogen or at least one carbon, R ₁
And R ₂ may be bonded to each other to have a cyclic structure. )

[0032]

[Formula 2] (R _1, R ₂ are each independently a hydrocarbon group having a hydrogen or at least one carbon, R ₁
And R ₂ may be bonded to each other to have a cyclic structure,
n is an integer of 1 to 3, and M is an n-valent cation. )

The content of these compounds is 0.2 parts by weight or less, preferably 0.1 parts by weight or less, based on 100 parts by weight of the solid content of the copolymer latex, and it is particularly preferable not to contain them. When this amount is large, the dip-molded product is discolored when it is repeatedly worn.

The dip molding composition of the present invention may further contain zinc oxide. The content of zinc oxide is 100 parts by weight of the solid content of the copolymer latex,
It is preferably 1.5 parts by weight or less, more preferably 0.1 part by weight or less.
1 part by weight, particularly preferably 0.2 to 0.4 part by weight. When the compounding amount is within this range, the balance between tensile strength and texture is excellent.

The dip molding composition of the present invention may further contain, if necessary, a pH adjusting agent, an antioxidant, a thickener,
Colorants, fillers and the like can be blended, and other latex such as natural rubber latex and isoprene rubber latex can be used in combination as long as the object of the present invention is not impaired.

The method for preparing the dip molding composition is not particularly limited, but sulfur, vulcanization accelerator, filler, thickener, etc. are added to the copolymer latex by using a dispersing machine such as a ball mill, a kneader or a disper. Examples of the method include mixing and mixing. In addition, using the above disperser in advance,
After preparing an aqueous dispersion of desired compounding ingredients other than the copolymer latex, it may be mixed with the remaining ingredients.

The dip-forming composition can be aged after preparation. The aging condition varies depending on the composition, but is from room temperature to about 40 ° C. for several hours to several days.

The solid content concentration of the dip molding composition is preferably 5 to 50% by weight, more preferably 10 to 45% by weight, and particularly preferably 20 to 40% by weight.
H is preferably 8 to 12, more preferably 9 to 11. To adjust the pH of the dip molding composition, a basic substance that can be used when adjusting the pH of the copolymer latex can be used. Among them, alkali metal hydroxides are preferable, and potassium hydroxide is more preferable.

The dip-molded article of the present invention is obtained by dip-molding the above-mentioned dip-molding composition. Dip molding is a method in which a mold is immersed in a dip molding composition to deposit the composition on the surface of the mold, and then the mold is pulled out of the composition and dried.

In the dip molding, a coagulant can be used, if necessary, before the mold is dipped in the dip molding composition or after the mold is pulled up from the dip molding composition. Specific examples of the method of using the coagulant include a method in which the mold before being dipped in the dip molding composition is immersed in a coagulant solution to attach the coagulant to the mold (anode coagulation dipping method),
There is a method of dipping a mold having the dip molding composition deposited therein into a coagulant solution (Teag coagulation dipping method). Above all, it is possible to obtain dip-molded products with little thickness unevenness.
The anode coagulation dipping method is preferred.

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; barium acetate, calcium acetate and zinc acetate. And the like; water-soluble polyvalent metal salts such as sulfates 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 are preferably used in the state of an aqueous solution. This aqueous solution may further contain a water-soluble organic solvent such as methyl alcohol or ethyl alcohol. The concentration in the case of an aqueous solution varies depending on the kind of the water-soluble polyvalent metal salt, but is preferably 5 to 70% by weight, more preferably 20 to 50% by weight.

In the dip molding, hot water treatment or heat treatment can be carried out if necessary after pulling up from the dip molding composition. By performing hot water treatment or heat treatment, the vulcanization reaction of the copolymer is promoted. The method of hot water treatment or heat treatment is not particularly limited, such as a method of immersing the mold having the composition deposited therein in hot water, a method of heating with hot air in an oven, a method of irradiating infrared rays, and the like. Is mentioned. The heating temperature is preferably 80 to 150
C., more preferably 100 to 130.degree. C., and the heating time is about 10 to 120 minutes.

Further, before or after heating the mold on which the composition is deposited, the mold is washed with water or warm water in order to remove water-soluble impurities (for example, excess emulsifier and coagulant). It is preferable.

The dip-molded product thus molded is detached from the mold. As the desorption method, a method of manually peeling from the mold or peeling by water pressure or compressed air pressure is adopted. However, even if the dip-formed product is in the process of being formed, if it has sufficient strength against desorption, it may be desorbed in the intermediate process and the process may be continued.

When the dip-molded product is a glove, inorganic fine particles such as talc, calcium carbonate, starch particles or organic particles are used in order to prevent the dip-molded products from sticking to each other at the contact surface and to improve the slippage during attachment / detachment. Fine particles may be dispersed on the surface of the glove, an elastomer layer containing these fine particles may be formed on the surface of the glove, or the surface layer of the glove may be chlorinated.

The dip-molded product of the present invention has a thickness of about 0.
05 to about 3 mm can be manufactured, especially the thickness is about 0.1
It can be suitably used for thin ones of about 0.3 mm. Specifically, medical supplies such as baby bottle nipples, droppers, tubes, and water pillows; toys and munitions such as balloons, dolls, and balls; industrial products such as pressure molding bags and gas storage bags; surgery. , Household, agricultural, fishing and industrial gloves; finger cots and the like. In particular, it is suitable for thin surgical gloves and gloves for manufacturing electronic parts.

[0047]

EXAMPLES The present invention will now be described in more detail by way of examples. The parts and% in the examples are by weight unless otherwise specified.

[Physical Property Evaluation Method] (Preparation of Test Piece for Physical Property Evaluation of Dip Molded Article) ASTM-
According to the test method described in D412, a rubber glove-shaped dip-molded product was punched with a dumbbell (Die-c) to prepare a test piece having a thickness of 0.1 to 0.13 mm. (Handle: Tensile stress at 300% extension) The test piece was pulled by a Tensilon universal testing machine (RTC-1225A: manufactured by Orientec Co., Ltd.) at a pulling speed of 500 mm / min, and the tensile stress at 300% extension was measured. . The smaller this value, the better the texture. (Tensile strength) The test piece was pulled at a pulling speed of 500 mm / min using a Tensilon universal testing machine, and the tensile strength immediately before breaking was measured.

(Discoloration after repeated wearing) The yellowness of the outer surface of the back of the hand of the dip-molded rubber glove is J
It was measured according to IS K7103. Using this, it was worn from 9 am to noon and from 2 pm to 5 pm, and light work was performed in a constant temperature and humidity room at 25 ° C. and a relative humidity of 50%. The detached gloves were washed with clean water, drained, and dried in a constant temperature and humidity room. After this work was continued for 3 days, the yellowness of the outer surface of the back of the detached glove was measured. The value obtained by subtracting the yellowness before starting the work from the yellowness after finishing the work was defined as the degree of yellowing. For each dip-molded product, the simple average value of the degree of yellowing obtained by 10 subjects is shown. The smaller this value, the more difficult it is to discolor even after repeated wearing.

(Production of Copolymer Latex) In a polymerization reactor purged with nitrogen, 27 parts of acrylonitrile, 69 parts of 1,3-butadiene, 4 parts of methacrylic acid, 0.5 part of t-dodecyl mercaptan (TDM), and 120 parts of soft water. Parts, sodium dodecylbenzenesulfonate 3.0 parts, β-naphthalenesulfonic acid formalin condensate sodium salt 0.5 parts,
0.3 part of potassium persulfate and 0.05 part of ethylenediaminetetraacetic acid sodium salt were charged, and the polymerization temperature was maintained at 38 ° C. to start the polymerization. After reacting for 25 hours, a reaction terminator was added to terminate the polymerization. The polymerization conversion rate at this time was 95%. After removing the unreacted monomer from the obtained copolymer latex, the pH and the solid content concentration of the copolymer latex are adjusted to obtain a solid content concentration of 45% and a pH of 8.3.
A copolymer latex of was obtained.

Example 1 Sulfur 1.5 parts, zinc oxide 0.
4. 4 parts, titanium oxide 2 parts, 2-mercaptobenzothiazole zinc 1.5 parts, 45% β-naphthalenesulfonic acid formalin condensate sodium salt aqueous solution 0.3 parts, potassium hydroxide 0.002 parts, and water 5. 372 parts were mixed by a ball mill to obtain a vulcanizing agent dispersion liquid having a solid content concentration of 50%.
333.3 parts of the copolymer latex obtained above adjusted to pH 10 and solid content concentration of 30% and 11.074 parts of the vulcanizing agent dispersion liquid are mixed to obtain a dip molding composition. It was On the other hand, the glove mold is immersed in a coagulant solution having a solid content concentration of 30% prepared by mixing 25 parts of calcium nitrate, 5 parts of calcium carbonate, 0.025 part of polyoxyethylene octylphenyl ether and 70 parts of water, and after pulling up. After drying, the coagulant was applied to the glove mold. Next, the glove mold to which the coagulant is attached is dipped in the dip-forming composition and pulled up, and then the glove mold is dried with a drier, followed by 1
The temperature was raised to 25 ° C. and heat treatment was performed for 20 minutes to obtain a solid film on the surface of the glove mold. After washing with running water for 20 minutes, peel off this solid film from the glove mold to a thickness of 0.1 to 0.13 m.
m, a rubber glove-like dip-molded product was obtained. The evaluation results of this dip-molded product are shown in Table 1.

Comparative Example 1 A vulcanizing agent dispersion was blended with 1.5 parts of sulfur, 0.4 parts of zinc oxide, 2 parts of titanium oxide, 1.5 parts of zinc dithiocarbamic acid salt, and 45% of β-naphthalene. Sulfonic acid formalin condensate sodium salt aqueous solution 0.3
Parts, 0.002 parts potassium hydroxide, and 5.372 water
Example 1 was repeated except that the parts were changed. The results are shown in Table 1.

(Comparative Example 2) The vulcanizing agent dispersion was blended with 1.5 parts of sulfur, 0.4 parts of zinc oxide, 2 parts of titanium oxide, 0.35 parts of dithiocarbamic acid zinc salt, and 2-mercaptobenzothiazole zinc. 1.15 parts, 45% β-naphthalenesulfonic acid formalin condensate sodium salt aqueous solution 0.3
Parts, 0.002 parts potassium hydroxide, and 5.372 water
Example 1 was repeated except that the parts were changed. The results are shown in Table 1.

[0054]

[Table 1]

The following can be seen from Table 1. The dip-molded article of Comparative Example 1 using only dibutylcarbamic acid zinc salt as the vulcanization accelerator has a high stress at the time of 300% elongation and is easily discolored when repeatedly worn. A combination of 2-mercaptobenzothiazole zinc salt and zinc dibutylcarbamate as a vulcanization accelerator, and a dip-molded article of Comparative Example 2 in which the amount of zinc dibutylcarbamate used is larger than the range specified in the present invention. Has excellent tensile strength and low stress when stretched by 300%, but easily discolors when repeatedly worn.

Compared to these comparative examples, the dip-molded article obtained from the dip-molding composition within the range specified in the present invention had excellent tensile strength, low stress at 300% elongation, and was repeatedly worn. It is hard to discolor.

[0057]

EFFECTS OF THE INVENTION According to the present invention, there are provided a dip-molded article which is excellent in texture and tensile strength and which is resistant to discoloration even after repeated wearing, and a dip-molding composition suitable for the dip-molded article.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/39 C08K 5/39 5/47 5/47 // B29K 9:00 B29K 9:00 B29L 31:48 B29L 31 : 48 F term (reference) 4F071 AA12 AB04 AB18A AC13 AE02 AF15 AF34 AH19 BB13 BC07 4F205 AA46 AB03 AB06 AC05 AH70 GA08 GB01 GC01 GE24 4J002 AC071 DA046 EV147 FD146 FD157 GB00 GC00 HA07

Claims (5)

[Claims] 1. A conjugated diene monomer of 50 to 84% by weight, an ethylenically unsaturated nitrile monomer of 15 to 40% by weight, an ethylenically unsaturated acid monomer of 1 to 10% by weight and a copolymerizable therewith. Vulcanization with or without copolymer latex obtained by polymerizing a monomer mixture consisting of 0 to 20% by weight of other ethylenically unsaturated monomer, sulfur, and dithiocarbamic acid derivative and its salt A dip molding composition comprising an accelerator, characterized in that the content of the dithiocarbamic acid derivative and its salt is 0.2 parts by weight or less based on 100 parts by weight of the solid content of the copolymer latex. Dip molding composition. 2. A copolymer latex solid content of 10
The dip molding composition according to claim 1, which contains or does not contain 1.5 parts by weight or less of zinc oxide based on 0 parts by weight. 3. The dip-forming composition according to claim 1, wherein the vulcanization accelerator is a thiazole. 4. The dip molding composition according to claim 1, wherein the vulcanization accelerator is a 2-mercaptobenzothiazole zinc salt. 5. A dip-formed product comprising the dip-forming composition according to claim 1.