JP7131255B2 - Method for manufacturing dip molded body - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention can suppress the occurrence of delayed-type allergy (Type IV) in addition to immediate-type allergy (Type I), effectively suppresses the occurrence of structural defects, has a flexible texture, and is durable. The present invention relates to a method for producing excellent dip-molded bodies.

Conventionally, there have been known dip-molded bodies that are used in contact with the human body, such as nipples, balloons, gloves, balloons, and sacks, by dip-molding a latex composition containing natural latex represented by natural rubber latex. there is However, since natural rubber latex contains proteins that cause allergic symptoms in the human body, it contains proteins that cause symptoms of immediate-type allergy (Type I) in the human body. As a dip-molded article to be used, there was a problem in some cases. Therefore, the use of synthetic nitrile rubber latex has been investigated.

For example, in US Pat. No. 5,200,008, zinc oxide, sulfur and a vulcanization accelerator are added to an emulsion comprising a carboxylated nitrile-butadiene random terpolymer of acrylonitrile, a carboxylic acid, and butadiene and having a total solids content of 15-25% by weight. is disclosed. However, while the technique of Patent Document 1 can prevent the occurrence of immediate-type allergies (Type I), in the case of a dip-molded body, sulfur and vulcanization accelerators contained in the dip-molded body can cause human body damage. In some cases, the allergic symptoms of delayed allergy (Type IV) occurred when touching.

On the other hand, for example, Patent Document 2 discloses a latex composition containing a carboxyl group-containing conjugated diene rubber latex and a metal compound containing a trivalent or higher valent metal, wherein the content ratio of the metal compound is is 0.1 to 1.5 parts by weight per 100 parts by weight of the carboxyl group-containing conjugated diene rubber.

Japanese Patent No. 5697578 WO2017/146238

According to the technique of Patent Document 2, it is possible to suppress the occurrence of delayed-type allergy (Type IV) in addition to immediate-type allergy (Type I). Compared to the case of using zinc oxide, sulfur, or a vulcanization accelerator as in the technique, the resulting dip-molded body is more likely to have structural defects such as pinholes, and as a result, the production efficiency is low. there were.

The present invention has been made in view of such circumstances, and can suppress the occurrence of delayed-type allergy (Type IV) in addition to immediate-type allergy (Type I), and effectively suppresses the occurrence of structural defects. It is an object of the present invention to provide a method for producing a dip-molded body having a soft texture and excellent durability.

As a result of intensive research to solve the above problems, the present inventors have found that dip molding is performed by dip molding a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber and a metal compound containing a trivalent or higher valent metal. When manufacturing the body, the dip mold is immersed in the latex composition twice, ie, a first dipping step and a second dipping step, and the dipping time in the first dipping step is adjusted. and the immersion time in the second immersion step within a specific range, the above problems can be solved, and the present invention has been completed.

That is, according to the present invention, a dip-molded article is produced by dip-molding a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber (A) and a metal compound (B) containing a trivalent or higher metal. a method,
a first dipping step of adhering the latex composition to the dip mold by dipping the dip mold in the latex composition;
and a second dipping step of dipping the dip mold to which the latex composition is attached in the first dipping step into the latex composition,
A method for producing a dip-formed body, wherein the immersion time in the first immersion step is 8 to 20 seconds, and the immersion time in the second immersion step is 3 seconds or more and the immersion time in the first immersion step or less. is provided.

In the method for producing a dip-molded article of the present invention, it is preferable that the immersion time in the second immersion step is shorter than the immersion time in the first immersion step by 3 seconds or more.

According to the present invention, it is possible to suppress the occurrence of delayed-type allergy (Type IV) in addition to immediate-type allergy (Type I), effectively suppress the occurrence of structural defects, and have a flexible texture and durability. It is possible to provide a method for producing a dip-molded article having excellent properties.

The method for producing a dip-molded article of the present invention comprises dip-molding a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber (A) and a metal compound (B) containing a trivalent or higher metal. A method of manufacturing a body, comprising:
a first dipping step of adhering the latex composition to the dip mold by dipping the dip mold in the latex composition;
and a second dipping step of dipping the dip mold to which the latex composition is attached in the first dipping step into the latex composition,
The immersion time in the first immersion step is 8 to 20 seconds, and the immersion time in the second immersion step is 3 seconds or more and the immersion time in the first immersion step or less.

<Latex composition>
First, the latex composition used in the production method of the present invention will be described.
The latex composition used in the present invention contains a latex of a carboxyl group-containing conjugated diene rubber (A) and a metal compound (B) containing a trivalent or higher metal.

The latex of the carboxyl group-containing conjugated diene rubber (A) may be a latex of a copolymer obtained by copolymerizing a conjugated diene monomer and an ethylenically unsaturated carboxylic acid monomer. It is preferably a latex of at least one rubber selected from rubber (a1), carboxyl group-containing styrene-butadiene rubber (a2) and carboxyl group-containing butadiene rubber (a3).

The latex of the carboxyl group-containing nitrile rubber (a1) is a latex of a copolymer obtained by copolymerizing an ethylenically unsaturated nitrile monomer in addition to a conjugated diene monomer and an ethylenically unsaturated carboxylic acid monomer. In addition to these, it may be a latex of a copolymer obtained by copolymerizing other ethylenically unsaturated monomers copolymerizable therewith, if necessary.

Conjugated diene monomers include, for example, 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 is preferred, and 1,3-butadiene is more preferred. These conjugated diene monomers can be used alone or in combination of two or more. The content of conjugated diene monomer units formed by the conjugated diene monomer in the carboxyl group-containing nitrile rubber (a1) is preferably 56 to 78% by weight, more preferably 56 to 73% by weight, More preferably 56 to 70% by weight. By setting the content of the conjugated diene monomer unit within the above range, the dip molded article obtained by the production method of the present invention has sufficient tensile strength, excellent texture, and increased elongation. can be

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, ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid 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, maleic acid Ethylenically unsaturated polyvalent carboxylic acid partial ester monomers such as monobutyl and mono-2-hydroxypropyl maleate; Among these, ethylenically unsaturated monocarboxylic acids are preferred, and methacrylic acid is particularly preferred. These ethylenically unsaturated carboxylic acid monomers can also be used as alkali metal salts or ammonium salts. Also, the ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. The content of ethylenically unsaturated carboxylic acid monomer units formed by ethylenically unsaturated carboxylic acid monomers in the carboxyl group-containing nitrile rubber (a1) is preferably 2 to 6.5% by weight. , more preferably 2 to 6% by weight, still more preferably 2 to 5% by weight, even more preferably 2 to 4.5% by weight, and particularly preferably 2.5 to 4.5% by weight. By setting the content of the ethylenically unsaturated carboxylic acid monomer unit within the above range, the dip-molded article obtained by the production method of the present invention has sufficient tensile strength, excellent texture, and high elongation. can be increased.

The ethylenically unsaturated nitrile monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a nitrile group. etc. Among them, acrylonitrile and methacrylonitrile are preferred, and acrylonitrile is more preferred. These ethylenically unsaturated nitrile monomers can be used alone or in combination of two or more. The content of ethylenically unsaturated nitrile monomer units formed by ethylenically unsaturated nitrile monomers in the carboxyl group-containing nitrile rubber (a1) is preferably 20 to 40% by weight, more preferably 25 to 40% by weight, more preferably 30 to 40% by weight. By setting the content of the ethylenically unsaturated nitrile monomer unit within the above range, the dip-molded article obtained by the production method of the present invention has sufficient tensile strength, excellent texture, and increased elongation. It can be assumed that

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

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

The latex of the carboxyl group-containing nitrile rubber (a1) can be obtained by copolymerizing a monomer mixture containing the above-described monomers, and is preferably copolymerized by emulsion polymerization. A conventionally known method can be employed as the emulsion polymerization method.

When the monomer mixture containing the above-mentioned monomers is subjected to emulsion polymerization, commonly used auxiliary materials for polymerization such as emulsifiers, polymerization initiators and molecular weight modifiers can be used. The method of adding these auxiliary materials for polymerization 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.

Examples of emulsifiers include, but are not limited to, nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters; potassium dodecylbenzenesulfonate, dodecylbenzene Anionic emulsifiers such as alkylbenzenesulfonates such as sodium sulfonate, higher alcohol sulfates, and alkylsulfosuccinates; cationic emulsifiers such as alkyltrimethylammonium chloride, dialkylammonium chloride, and benzylammonium chloride; α,β-unsaturation Copolymerizable emulsifiers such as carboxylic acid sulfoesters, α,β-unsaturated carboxylic acid sulfate esters, and sulfoalkylaryl ethers can be used. Among them, anionic emulsifiers are preferred, alkylbenzenesulfonates are more preferred, and potassium dodecylbenzenesulfonate and sodium dodecylbenzenesulfonate are particularly preferred. These emulsifiers can be used alone or in combination of two or more. The amount of emulsifier used is preferably 0.1 to 10 parts by weight per 100 parts by weight of the monomer mixture.

The polymerization initiator is not particularly limited, but for example, sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, inorganic peroxides such as 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, and benzoyl peroxide; azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, and methyl azobisisobutyrate; can be mentioned. These polymerization initiators can be used alone or in combination of two or more. The amount of polymerization initiator used is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 2 parts by weight, per 100 parts by weight of the monomer mixture.

Moreover, a peroxide initiator can be used as a redox polymerization initiator in combination with a reducing agent. The reducing agent is not particularly limited, but compounds containing metal ions in a reduced state such as ferrous sulfate and cuprous naphthenate; sulfonic acid compounds such as sodium methanesulfonate; amine compounds such as dimethylaniline. ; and the like. These reducing agents can be used alone or in combination of 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, per 100 parts by weight of all the monomers used.

Methods of adding the monomers include, for example, a method of collectively adding the monomers used in the reaction vessel, a method of continuously or intermittently adding the monomers as the polymerization progresses, and a method of partially adding the monomers. reaction to a specific conversion rate, and then the remaining monomers are added continuously or intermittently for polymerization, and any method may be employed. When the monomers are mixed and added continuously or intermittently, the composition of the mixture can be constant or varied. Further, each monomer may be added to the reaction vessel after previously mixing various monomers to be used, or may be added to the reaction vessel separately.

Furthermore, if necessary, auxiliary materials for polymerization such as chelating agents, dispersants, pH adjusters, deoxidants, particle size adjusters, etc. can be used, and the types and amounts of these are not particularly limited.

The polymerization temperature for emulsion polymerization is not particularly limited, but is usually 3 to 95°C, preferably 5 to 60°C. The polymerization time is about 5 to 40 hours.

As described above, the monomer mixture is emulsion-polymerized, 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.

Examples of the polymerization terminator include, but are not limited to, hydroxylamine, hydroxylamine sulfate, diethylhydroxylamine, hydroxylaminesulfonic acid and alkali metal salts thereof, sodium dimethyldithiocarbamate, hydroquinone derivatives, catechol derivatives, and hydroxydimethyl 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, unreacted monomers are removed, and the solid content concentration and pH are adjusted to obtain a latex of carboxyl group-containing nitrile rubber (a1).

In addition, to the latex of the carboxyl group-containing nitrile rubber (a1), an anti-aging agent, an antiseptic, an antibacterial agent, a dispersing agent, and the like may be added as appropriate.

The number average particle size of the carboxyl group-containing nitrile rubber (a1) 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 amount of emulsifier and polymerization initiator used.

Further, the latex of the carboxyl group-containing styrene-butadiene rubber (a2) is a copolymer obtained by copolymerizing styrene in addition to 1,3-butadiene as a conjugated diene monomer and an ethylenically unsaturated carboxylic acid monomer. It is a latex of a polymer, and in addition to these, it may be a latex of a copolymer obtained by copolymerizing other ethylenically unsaturated monomers copolymerizable therewith, if necessary. .

The content of butadiene units formed from 1,3-butadiene in the carboxyl group-containing styrene-butadiene rubber (a2) is preferably 56 to 78% by weight, more preferably 56 to 73% by weight, and still more preferably. is 56-68% by weight. By setting the content of the butadiene unit within the above range, the dip-molded article obtained by the production method of the present invention can have sufficient tensile strength, excellent texture, and increased elongation. can.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a carboxyl group. can be used. The content of ethylenically unsaturated carboxylic acid monomer units formed by ethylenically unsaturated carboxylic acid monomers in the carboxyl group-containing styrene-butadiene rubber (a2) is preferably 2 to 6.5% by weight. , more preferably 2 to 6% by weight, still more preferably 2 to 5% by weight, still more preferably 2 to 4.5% by weight, and particularly preferably 2.5 to 4.5% by weight. By setting the content of the ethylenically unsaturated carboxylic acid monomer unit within the above range, the dip-molded article obtained by the production method of the present invention has sufficient tensile strength, excellent texture, and high elongation. can be increased.

The content of styrene units formed by styrene in the carboxyl group-containing styrene-butadiene rubber (a2) is preferably 20 to 40% by weight, more preferably 25 to 40% by weight, still more preferably 30 to 40% by weight. % by weight. By setting the content of the styrene unit within the above range, the dip-molded article obtained by the production method of the present invention can have sufficient tensile strength, excellent texture, and increased elongation. can.

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

The carboxyl group-containing styrene-butadiene rubber (a2) latex used in the present invention can be obtained by copolymerizing a monomer mixture containing the above-described monomers. preferable. As for the emulsion polymerization method, the same auxiliary materials for polymerization as in the case of the carboxyl group-containing nitrile rubber (a1) may be used and polymerization may be carried out in the same manner.

If necessary, anti-aging agents, preservatives, antibacterial agents, dispersants and the like may be added to the carboxyl group-containing styrene-butadiene rubber (a2) latex used in the present invention.

The number average particle size of the carboxyl group-containing styrene-butadiene rubber (a2) latex used in the present invention 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 amount of emulsifier and polymerization initiator used.

The latex of the carboxyl group-containing conjugated diene rubber (a3) is a latex of a copolymer obtained by copolymerizing a conjugated diene monomer and an ethylenically unsaturated carboxylic acid monomer. A latex of a copolymer obtained by copolymerizing other ethylenically unsaturated monomers copolymerizable therewith, which is used as appropriate, may also be used.

The content of conjugated diene monomer units formed by the conjugated diene monomer in the carboxyl group-containing conjugated diene rubber (a3) is preferably 80 to 98% by weight, more preferably 90 to 98% by weight, More preferably, it is 95 to 97.5% by weight. By setting the content of the conjugated diene monomer unit within the above range, the dip molded article obtained by the production method of the present invention has sufficient tensile strength, excellent texture, and increased elongation. can be

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a carboxyl group. can be used. The content of ethylenically unsaturated carboxylic acid monomer units formed by ethylenically unsaturated carboxylic acid monomers in the carboxyl group-containing conjugated diene rubber (a3) is preferably 2 to 10% by weight, and more preferably 2 to 7.5% by weight, more preferably 2 to 6.5% by weight, even more preferably 2 to 6% by weight, particularly preferably 2 to 5% by weight, most preferably 2.5 to 5% by weight. % by weight. By setting the content of the ethylenically unsaturated carboxylic acid monomer unit within the above range, the dip-molded article obtained by the production method of the present invention has sufficient tensile strength, excellent texture, and high elongation. can be increased.

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

Other ethylenically unsaturated monomers copolymerizable with the conjugated diene monomer and the ethylenically unsaturated carboxylic acid monomer are, for example, the same as the latex of the carboxyl group-containing nitrile rubber (a1) described above. (excluding styrene). The content of other monomer units formed by other ethylenically unsaturated monomers in the carboxyl group-containing conjugated diene rubber (a3) is preferably 10% by weight or less, more preferably 5% by weight. 3% by weight or less, and more preferably 3% by weight or less.

The latex of the carboxyl group-containing conjugated diene rubber (a3) used in the present invention can be obtained by copolymerizing a monomer mixture containing the above-described monomers, and is preferably copolymerized by emulsion polymerization. As for the emulsion polymerization method, the same auxiliary materials for polymerization as in the case of the carboxyl group-containing nitrile rubber (a1) may be used and polymerization may be carried out in the same manner.

The latex composition used in the present invention contains a metal compound (B) containing a trivalent or higher valent metal in addition to the latex of the carboxyl group-containing conjugated diene rubber (A) described above.

The metal compound (B) containing a metal having a valence of 2 or higher reacts with the carboxyl group contained in the carboxyl group-containing conjugated diene rubber (A) described above, thereby forming a crosslinked structure by bonding metal ions. , which acts as a cross-linking agent.

According to the present invention, a metal compound (B) containing a trivalent or higher metal is used as a cross-linking agent instead of sulfur, which is usually used as a cross-linking agent. Since it does not require a sulfur accelerator, in addition to immediate allergy (Type I), delayed allergy (Type IV) caused by sulfur and sulfur-containing vulcanization accelerators can also occur. It can be effectively suppressed.

The metal compound (B) containing a trivalent or higher metal is not particularly limited as long as it is a compound containing a trivalent or higher metal. Examples thereof include aluminum compounds, cobalt compounds, zirconium compounds, and titanium compounds. Among these, an aluminum compound is preferred because it can more favorably crosslink the carboxyl group-containing conjugated diene rubber (A) contained in the latex.

Examples of aluminum compounds include, but are not limited to, aluminum oxide, aluminum chloride, aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum metal, aluminum ammonium sulfate, aluminum bromide, aluminum fluoride, aluminum potassium sulfate, aluminum isopropoxide, sodium aluminate, potassium aluminate, sodium aluminum sulfite, and the like. In addition, these aluminum compounds can be used individually or in combination of 2 or more types. Among these, sodium aluminate is preferable from the point that the effect of the present invention can be made more remarkable.

The content of the metal compound (B) containing a trivalent or higher metal in the latex composition used in the present invention is preferably based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A) contained in the latex. is 0.1 to 5 parts by weight, more preferably 0.5 to 2.5 parts by weight, still more preferably 0.5 to 2.0 parts by weight. By setting the content ratio of the metal compound (B) containing a trivalent or higher metal in the above range, the stability of the latex composition is improved and the cross-linking at the time of cross-linking is made sufficient. be able to.

Further, the latex composition used in the present invention includes, in addition to the latex of the carboxyl group-containing conjugated diene rubber (A) described above and the metal compound (B) containing a trivalent or higher metal, a sugar (c1) and a sugar alcohol. It preferably contains at least one alcoholic hydroxyl group-containing compound (C) selected from (c2), hydroxy acid (c3) and hydroxy acid salt (c4).

By further containing the alcoholic hydroxyl group-containing compound (C), the stability of the latex composition can be further enhanced, and the resulting dip molded product has high tensile strength, high elongation, and a soft texture. In addition to having a high stress retention rate.

The alcoholic hydroxyl group-containing compound (C) used in the present invention is at least one selected from sugars (c1), sugar alcohols (c2), hydroxy acids (c3) and hydroxy acid salts (c4). , it is preferable to use at least one selected from the sugar alcohol (c2) and the hydroxy acid salt (c4) from the viewpoint that the addition effect can be further enhanced. Further, when two or more types are used in combination as the alcoholic hydroxyl group-containing compound (C), at least one selected from sugars (c1) and sugar alcohols (c2), hydroxy acid (c3) and hydroxy acid salt It is preferably used in combination with at least one selected from (c4), and more preferably used in combination with sugar alcohol (c2) and hydroxy acid salt (c4).

Saccharides (c1) are not particularly limited as long as they are monosaccharides or polysaccharides in which two or more monosaccharides are linked by glycosidic bonds. Examples include erythrose, threose, ribose, lyxose, xylose, arabinose and allose. , talose, gulose, altrose, galactose, idose, erythrulose, xylulose, ribulose, psicose, fructose, sorbose, tagatose; trehalose, maltose, isomaltose, cellobiose, gentiobiose, melibiose, lactose, sucrose, palatinose, etc. disaccharides; maltotriose, isomaltotriose, panose, cellotriose, manninotriose, solatriose, melezitose, planteose, gentianose, umbelliferose, lactosucrose, trisaccharides such as raffinose; maltotetraose, isomalt homooligosaccharides such as tetraose; tetrasaccharides such as stachyose, cellotetraose, scorodose, lyquinose and panose; pentasaccharides such as maltopentaose and isomaltopentaose; hexasaccharides such as maltohexaose and isomaltohexaose; is mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The sugar alcohol (c2) is not particularly limited as long as it is a monosaccharide or polysaccharide sugar alcohol. Examples include tritol such as glycerin; tetritol such as erythritol, D-threitol and L-threitol; pentitols such as L-arabinitol, xylitol, ribitol and pentaerythritol; pentaerythritol; hexitols such as sorbitol, D-iditol, galactitol, D-glucitol and mannitol; heptitols such as boremitol and perseitol; D-erythro-D- octitol such as galacto-octitol; These may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, hexitol, which is a sugar alcohol having 6 carbon atoms, is preferred, and sorbitol is more preferred.

The hydroxy acid (c3) is not particularly limited as long as it is a carboxylic acid having a hydroxyl group. Examples include glycolic acid, lactic acid, tartronic acid, glyceric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, γ-hydroxy Fatty acids such as butyric acid, malic acid, 3-methylmalic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucic acid, mevalonic acid, pantoic acid, ricinoleic acid, ricineraidic acid, cerebronic acid, quinic acid, shikimic acid, serine Hydroxy acids; salicylic acid, creosote acid (homosalicylic acid, hydroxy(methyl)benzoic acid), vanillic acid, syringic acid, hydroxypropanoic acid, hydroxypentanoic acid, hydroxyhexanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, hydroxynonanoic acid, Monomers such as hydroxydecanoic acid, hydroxyundecanoic acid, hydroxydododecanoic acid, hydroxytridecanoic acid, hydroxytetradecanoic acid, hydroxypentadecanic acid, hydroxyheptadecanoic acid, hydroxyoctadecanoic acid, hydroxynonadecanoic acid, hydroxyicosanoic acid, ricinoleic acid, etc. Hydroxybenzoic acid derivatives, pyrocatechuic acid, resorcylic acid, protocatechuic acid, gentisic acid, dihydroxybenzoic acid derivatives such as orceric acid, trihydroxybenzoic acid derivatives such as gallic acid, phenylacetic acid derivatives such as mandelic acid, benzilic acid, atrolactinic acid aromatic hydroxy acids such as cinnamic acid/hydrocinnamic acid derivatives such as , melilotic acid, phloretic acid, coumaric acid, umberic acid, caffeic acid, ferulic acid, and sinapinic acid; These may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, aliphatic hydroxy acids are preferred, aliphatic α-hydroxy acids are more preferred, glycolic acid, lactic acid, tartronic acid, glyceric acid, malic acid, tartaric acid and citric acid are more preferred, and glycolic acid is particularly preferred.

The hydroxy acid salt (c4) is not particularly limited as long as it is a salt of a hydroxy acid, and includes metal salts of hydroxy acids exemplified as specific examples of the hydroxy acid (c3), such as sodium and potassium. salts of alkali metals; and salts of alkaline earth metals such as calcium and magnesium. As the hydroxy acid salt (c4), one type may be used alone, or two or more types may be used in combination. As the hydroxy acid salt (c4), an alkali metal salt of a hydroxy acid is preferred, and a sodium salt of a hydroxy acid is preferred. The hydroxy acid constituting the hydroxy acid salt (c4) is preferably an aliphatic hydroxy acid, more preferably an aliphatic α-hydroxy acid, such as glycolic acid, lactic acid, tartronic acid, glyceric acid, malic acid, tartaric acid, citric acid, Acids are more preferred, and glycolic acid is particularly preferred. That is, sodium glycolate is particularly suitable as the hydroxy acid salt (c4).

In the latex composition used in the present invention, the content of the alcoholic hydroxyl group-containing compound (C) is adjusted to the metal compound (B) containing a trivalent or higher metal, and the "metal compound containing a trivalent or higher metal (B ): alcoholic hydroxyl group-containing compound (C)”, the weight ratio is preferably in the range of 1:0.1 to 1:50, more preferably in the range of 1:0.2 to 1:45. and more preferably in the range of 1:0.3 to 1:30. By setting the content of the alcoholic hydroxyl group-containing compound (C) to the above range with respect to the metal compound (B) containing a trivalent or higher metal, the effect of adding the alcoholic hydroxyl group-containing compound (C) can be further enhanced. .

In addition, the content of the alcoholic hydroxyl group-containing compound (C) may be an amount in which the content relative to the metal compound (B) containing a trivalent or higher metal is within the above range, but the content of the carboxyl group contained in the latex The content per 100 parts by weight of the conjugated diene rubber (A) is preferably 0.03 to 15 parts by weight, more preferably 0.05 to 10 parts by weight.

The tex composition used in the present invention comprises, for example, a latex of a carboxyl group-containing conjugated diene rubber (A), a metal compound (B) containing a trivalent or higher metal, and an alcoholic hydroxyl group-containing compound used as necessary. It can be obtained by blending (C). As a method of blending the latex of the carboxyl group-containing conjugated diene rubber (A) with the metal compound (B) containing a trivalent or higher metal and the alcoholic hydroxyl group-containing compound (C) that is used as necessary, Although not particularly limited, the fact that the metal compound (B) containing a trivalent or higher metal and the alcoholic hydroxyl group-containing compound (C) that is used as necessary can be well dispersed in the resulting latex composition. More preferably, the metal compound (B) containing a trivalent or higher valent metal and the alcoholic hydroxyl group-containing compound (C) used as necessary are dissolved in water or alcohol and added in the form of an aqueous solution or an alcoholic solution. Moreover, it is preferable to add a stabilizing agent such as a chelating agent or a buffering agent in order to increase the stability of the solution when it is dissolved.

In addition, the tex composition used in the present invention includes the latex of the carboxyl group-containing conjugated diene rubber (A) described above, the metal compound (B) containing a trivalent or higher metal, and an alcoholic hydroxyl group used as necessary. In addition to the contained compound (C), if desired, fillers, pH adjusters, thickeners, antioxidants, dispersants, pigments, fillers, softeners, etc. may be blended.

The solid content concentration of the latex composition used in the present invention is preferably 10 to 40% by weight, more preferably 15 to 35% by weight. Further, the pH of the latex composition of the present invention is preferably 7.5 to 12.0, more preferably 7.5 to 11.0, still more preferably 7.5 to 9.4, particularly preferably 7.5. ~9.2.

<Manufacturing method of dip molded product>
The method for producing a dip-molded article of the present invention includes a first dipping step of adhering the latex composition to the dip mold by dipping the dip mold in the latex composition described above, and a first dipping step. and a second dipping step of dipping the dip mold to which the latex composition is attached in the latex composition described above.
Further, in the method for producing a dip molded body of the present invention, the immersion time in the first immersion step is 8 to 20 seconds, the immersion time in the second immersion step is 3 seconds or more, and the first immersion step The immersion time in

First, in the dip-molded article manufacturing method of the present invention, the latex composition adheres to the dip molding die by dipping the dip molding die in the latex composition described above as the first dipping step. The dip mold is then pulled out of the latex composition, and the latex composition adhering to the surface of the dip mold is dried.

Next, as a second dipping step, the dipping mold having the latex composition adhered to the surface thereof in the first dipping step is dipped again in the above-mentioned latex composition, thereby further adhering the latex composition. . The dip mold is then pulled out of the latex composition, and the latex composition adhering to the surface of the dip mold is dried.

In the production method of the present invention, the immersion operation in the latex composition is performed twice as the first immersion step and the second immersion step. The immersion step is 8 to 20 seconds, and the second immersion step is 3 seconds or longer and the immersion time in the first immersion step or less. According to the manufacturing method of the present invention, the immersion operation in the latex composition is performed twice, and the immersion time is controlled as described above, so that the obtained dip-molded article is effectively free from structural defects. It is restrained, has a soft texture, and can be made excellent in durability. Specifically, it is possible to effectively prevent appearance defects such as sagging and adhesion of aggregates, and structural defects such as cracks and pinholes in the resulting dip-molded body. It has a soft texture and can be made excellent in durability.

In the production method of the present invention, the immersion time t1 in the first immersion step is 8 to 20 seconds, preferably 8 to 18 seconds, more preferably 8 to 16 seconds. If the immersion time t1 in the first immersion step is too short, cracks will occur in the resulting dip-molded article. Defects and pinholes will occur.

The immersion time t2 in the second immersion step is 3 seconds or more and the immersion time t2 or less in the first immersion step, preferably 3 seconds or more and the immersion time t1 in the first immersion step 3 seconds or more (that is, 3 seconds or more and (t1-3) seconds or less), more preferably 3 seconds or more and 5 seconds or more shorter than the immersion time t1 in the first immersion step time (ie, greater than or equal to 3 seconds and less than or equal to (t1-5) seconds). If the immersion time t2 in the second immersion step is too short, cracks will occur in the dip-molded body obtained. occurs.

Although the total time of the immersion time t1 in the first immersion step and the immersion time t2 in the second immersion step is not particularly limited, it is preferable from the viewpoint of obtaining a dip-molded article having sufficient mechanical properties. is 13 to 37 seconds, more preferably 11 to 27 seconds.

In the manufacturing method of the present invention, the immersion time t1 in the first immersion step and the immersion time t2 in the second immersion step are determined by immersing the dipping mold to a predetermined deepest position and then at the deepest position. means holding time. That is, the dipping operation in dip molding is usually performed by (1) moving the dip mold toward the latex composition filled in the dipping tank, thereby moving the dip mold into the latex composition to a predetermined deepest position. (2) then hold the dip mold at the predetermined deepest position for a predetermined time; and (3) then move the dip mold away from the latex composition filled in the dip bath. In the present invention, the immersion time t1 in the first immersion step and the immersion time t2 in the second immersion step mean the time in (2) above. In the production method of the present invention, the times (1) and (3) (that is, the time to reach the predetermined deepest position after the start of immersion in the latex composition, and the time to pull up from the latex composition). are not particularly limited, but are usually each 5 seconds or less. In the dip molding, instead of moving the dip mold toward the latex composition filled in the dipping bath, a dipping bath filled with the latex composition is moved toward the dip mold. may be adopted.

In the first dipping step and the second dipping step, the latex composition used is not particularly limited, but the same latex composition may be used, or different latex compositions may be used. However, from the viewpoint that structural defects can be suppressed more appropriately, it is preferable to use a latex composition having substantially the same solid content concentration in the first immersion step and the second immersion step. More preferably, the first dipping step and the second dipping step use latex compositions having substantially the same composition and solids concentration.

In addition, in the dipping operation in the first dipping step, the dip mold may be preheated before dipping. In addition, in the dipping operation in the first dipping step, a coagulant may be used as necessary before dipping the dip mold into the latex composition.

A specific example of using a coagulant in the first dipping step is a method of immersing a dip mold before being dipped in the latex composition in a coagulant solution to attach the coagulant to the dip mold ( Anode cohesive dipping method) is preferably used.

Coagulants include, for example, 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; sulfates such as calcium sulfate, magnesium sulfate, and aluminum sulfate; Among them, calcium chloride and calcium nitrate are preferred.
Coagulants are typically used as solutions of water, alcohols, or mixtures thereof. The coagulant concentration is usually 5-50% by weight, preferably 10-35% by weight.

In the first dipping step, the temperature of the latex composition used during the dipping treatment is not particularly limited, but is preferably 10 to 50°C. In the first dipping step, the drying conditions after pulling up the dip mold from the latex composition are not particularly limited, but the conditions are preferably 10 to 60° C. and 5 seconds to 5 minutes. .

Also in the dipping operation in the second dipping step, the dipping mold to which the latex composition was adhered in the first dipping step and before dipping may be preheated.

In addition, in the second dipping step, the temperature of the latex composition used in the dipping treatment is not particularly limited, but is preferably 10 to 50°C. Furthermore, in the second dipping step, the drying conditions after pulling up the dip mold from the latex composition are not particularly limited, but conditions of 10 to 60° C. and 1 to 10 minutes are preferable.

Then, in the manufacturing method of the present invention, the dip molding layer formed on the surface of the dip molding die through the above-described first dipping step and second dipping step is subjected to a heat treatment to obtain 2 It is preferable to carry out cross-linking with a metal compound (B) containing a metal with a higher valence. The cross-linking at this time progresses by metal ion bonding by reacting the metal compound (B) containing a divalent or higher valent metal with the carboxyl groups contained in the carboxyl group-containing conjugated diene rubber (A). In addition, before the heat treatment, the dip molded layer is immersed in water, preferably warm water of 30 to 70° C., for about 1 to 60 minutes to remove water-soluble impurities (for example, excess emulsifier, coagulant, etc.). may be removed. The operation for removing water-soluble impurities may be performed after heat-treating the dip-molded layer, but it is preferable to perform the operation before heat-treatment from the viewpoint of more efficient removal of water-soluble impurities.

Crosslinking of the dip-molded layer with the metal compound (B) containing a divalent or higher valent metal is usually carried out by heat treatment at a temperature of 80 to 150° C., preferably for 10 to 130 minutes. As a heating method, external heating using infrared rays or heated air or internal heating using high frequency waves can be employed. Among them, external heating with heated air is preferable.

Then, the dip-molded article can be obtained by removing the cross-linked dip-molded layer from the dip-molded mold. As a detachment method, a method of manually peeling from the dip mold or a method of peeling by water pressure or compressed air pressure can be adopted. After desorption, heat treatment may be performed at a temperature of 60 to 120° C. for 10 to 120 minutes.

Further, in the present invention, the obtained dip-molded article may be further irradiated with radiation. By irradiating the obtained dip-formed article with radiation, the dip-formed article obtained by the production method of the present invention has a large elongation and a soft texture, while improving the tensile strength and stress retention rate. can be higher. The reason why the tensile strength and stress retention rate can be further increased by irradiation is not necessarily clear, but by irradiation, the carboxyl group-containing conjugated diene rubber contained in the latex composition ( It is believed that the carbon-carbon double bond portion of the conjugated diene monomer unit of A) can be crosslinked, and the formation of such crosslinks can further increase the tensile strength and stress retention rate.

The radiation to be irradiated includes electromagnetic radiation such as gamma rays and X-rays, and particle radiation such as electron beams and beta rays. γ-rays or electron beams are preferred, and γ-rays are most preferred, from the viewpoint of being able to further enhance the effect of improving the stress retention rate and the like. The absorbed dose in irradiation with radiation such as gamma rays is preferably in the range of 1 to 500 kGy, more preferably in the range of 5 to 300 kGy, and still more preferably in the range of 10 to 100 kGy. In addition, the irradiation energy and time when performing γ-ray irradiation should be set to appropriate conditions in consideration of the target absorbed dose of radiation such as γ-rays and the resistance to radiation such as γ-rays of the object to be irradiated. desirable. The irradiation energy of radiation such as gamma rays may be in the range of 0.1 to 10 MeV, preferably 1.17 MeV and 1.33 MeV when cobalt 60 is used as the radiation source, or cesium 137 is used as the radiation source. An energy of 0.66 MeV to be irradiated at times is desirable. The irradiation time of radiation such as γ-rays is not particularly limited because it is the time required to obtain the desired absorption dose of radiation such as γ-rays.

The thickness of the dip-molded body obtained by the production method of the present invention is not particularly limited, but from the viewpoint of ensuring sufficient mechanical strength, it is preferably 0.05 to 0.3 mm, and more preferably. is 0.1 to 0.2 mm.

Thus, the dip molded article obtained by the production method of the present invention contains the latex of the carboxyl group-containing conjugated diene rubber (A) and the metal compound (B) containing a trivalent or higher metal. Since it is obtained using a latex composition, it can suppress the occurrence of delayed-type allergy (Type IV) in addition to immediate-type allergy (Type I), and can be used for dip-molded latex compositions. The immersion is performed twice, immersed in the first immersion step and immersed in the second immersion step, and the immersion time in the first immersion step and the immersion time in the second immersion step are within a specific range. Therefore, the occurrence of structural defects is effectively suppressed, the texture is flexible, and the durability is excellent. Therefore, the dip-molded article obtained by the production method of the present invention is suitable for glove applications, especially surgical gloves, taking advantage of such properties. Alternatively, the dip molded article obtained by the production method of the present invention can be used not only for gloves but also for nursing bottle nipples, droppers, tubes, water pillows, balloon sacks, catheters, condoms and other medical supplies; balloons, dolls, balls and the like. Toys; industrial products such as pressure molding bags and gas storage bags; finger sacks and the like.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples. In addition, the following "parts" are by weight unless otherwise specified. Various physical properties were measured as follows.

<Cracks in Dip Formed Body>
Cuff portions of 20 dip-molded articles (gloves) obtained by dip molding were visually checked for cracks and evaluated according to the following criteria.
◯: No cracks were observed in all of the 20 dip-molded products.
x: Cracks were found in one or more of the 20 dip-molded bodies.

<Poor Appearance of Dip Molded Body>
The cuff portions of 20 dip-molded articles (gloves) obtained by dip molding were visually checked for the presence or absence of adhesion of aggregates and the presence or absence of sagging at the fingertips, and were evaluated according to the following criteria. .
◯: Neither adherence of agglomerates nor sagging at fingertips was observed for all 20 dip-molded articles.
x: Adhesion of aggregates or sagging at fingertips was observed in one or more dip-molded bodies out of 20 dip-molded bodies.

<Pinhole in Dip Mold>
The cuff portions of 20 dip-molded articles (gloves) obtained by dip molding were visually checked for pinholes and evaluated according to the following criteria.
◯: No pinholes were observed in all of the 20 dip-molded products.
x: Occurrence of pinholes was observed in one or more of the 20 dip-molded bodies.

<Thickness of dip molded body>
For 20 dip-molded bodies (gloves) obtained by dip molding, the film thickness of the cuff portion was measured using a digital thickness gauge (manufactured by Toyo Seiki Seisakusho Co., Ltd.) as a measuring device. The median value of the measured values for each dip-molded article (glove) was obtained and taken as the film thickness of the dip-molded article.

<Stress at 500% elongation of dip molded product>
The cuff portions of 20 dip-molded bodies (gloves) obtained by dip molding were cut into 20 dumbbell-shaped test pieces using dumbbells (Die-C: manufactured by Dumbbell Co.) according to ASTM D-412. made. Then, the obtained 20 test pieces are pulled at a tensile speed of 500 mm / min, the stress at 500% elongation is measured, the median value of the measured values for 20 test pieces is obtained, and this is a dip molded body It was defined as the stress at 500% elongation. The smaller the stress at 500% elongation, the softer the texture, which is preferable.

<Mounting endurance test of dip molded body>
Twenty dip-molded articles (gloves) obtained by dip-molding were worn by clerical workers, and a wearing endurance test was conducted in which light work was performed for 6 hours. In the wearing durability test, the time at which the dip molded article (glove) was torn was measured during the test, and the median value of 20 tests (median time at which the dip molded article (glove) was torn) was obtained, This was taken as the wear endurance time. The wearing endurance time was evaluated only in hours, and minutes were discarded (for example, 3 hours and 35 minutes was set to 3 hours). The longer the wearing endurance time, the better the durability, which is preferable.

<Production Example 1 (production of latex of carboxyl group-containing nitrile rubber (a1-1))>
63 parts of 1,3-butadiene, 34 parts of acrylonitrile, 3 parts of methacrylic acid, 0.25 parts of t-dodecylmercaptan as a chain transfer agent, 132 parts of deionized water, and sodium dodecylbenzenesulfonate are placed in a pressure-resistant polymerization reactor equipped with a stirrer. 3 parts, 1 part of sodium β-naphthalenesulfonate formalin condensate, 0.3 parts of potassium persulfate and 0.005 parts of sodium ethylenediaminetetraacetate were charged, and the polymerization was started while maintaining the polymerization temperature at 37°C. Then, when the polymerization conversion rate reached 70%, the polymerization temperature was raised to 43° C., and the reaction was continued until the polymerization conversion rate reached 95%. .1 part was added to terminate the polymerization reaction. Then, from the resulting copolymer latex, the unreacted monomer is distilled off under reduced pressure, and then the solid content concentration and pH are adjusted to obtain a carboxyl A latex of group-containing nitrile rubber (a1-1) was obtained. The composition of the obtained carboxyl group-containing nitrile rubber (a1-1) was 63% by weight of 1,3-butadiene units, 34% by weight of acrylonitrile units and 3% by weight of methacrylic acid units.

<Example 1>
(Preparation of latex composition)
To 250 parts of the carboxyl group-containing nitrile rubber (a1-1) latex obtained in Production Example 1 (100 parts in terms of the carboxyl group-containing nitrile rubber (a1-1)), 0.25 parts of sodium aluminate and 0.25 parts of sorbitol were added. A mixed aqueous solution of 375 parts and 0.375 parts of sodium glycolate was added. Then, deionized water was added to this to adjust the solid content concentration to 30% by weight, thereby obtaining a latex composition.
The resulting latex composition was then divided in half and placed in separate dipping tanks, one serving as the first dipping tank and the other as the second dipping tank.

(Manufacturing of dip molded body)
An aqueous coagulant solution was prepared by mixing 30 parts of calcium nitrate, 0.05 parts of polyethylene glycol octylphenyl ether as a nonionic emulsifier, and 70 parts of water. Next, a ceramic glove mold preheated to 70° C. is immersed in this coagulant aqueous solution for 5 seconds, pulled out, and dried at a temperature of 70° C. for 10 minutes to adhere the coagulant to the glove mold. rice field. Then, the glove mold to which the coagulant was adhered was immersed in the first immersion tank prepared above for 12 seconds (that is, the holding time at the predetermined deepest position was 12 seconds), and after being pulled up, the temperature The latex composition was adhered to the glove mold by drying at 25°C for 30 seconds. Then, the glove mold to which the latex composition was adhered was immersed in the second immersion tank prepared above for 3 seconds (that is, the holding time at the predetermined deepest position was 3 seconds), and after being pulled up, It was dried at a temperature of 25° C. for 5 minutes, and then immersed in warm water of 50° C. for 90 seconds to elute water-soluble impurities, thereby forming a dip-molded layer on the glove mold. Next, the glove mold with the dip-molded layer formed thereon is heat-treated at a temperature of 125° C. for 25 minutes to crosslink the dip-molded layer, the crosslinked dip-molded layer is peeled off from the glove mold, and the dip-molded body before γ-ray irradiation is obtained. got
In this example, after the start of immersion in the first immersion tank and the second immersion tank, the time to reach the predetermined deepest position and the time to pull up from the first immersion tank and the second immersion tank were , were set to 5 seconds (the same applies to Examples 1 to 6, Comparative Examples 1 to 7, and Reference Examples 1 and 2, which will be described later).

Next, the obtained dip-molded body before γ-ray irradiation was irradiated with γ-rays using cobalt 60 as a radiation source until the absorbed dose reached 30 kGy. The irradiation time was 3 hours. Thus, a dip-molded article (glove) after γ-ray irradiation was obtained. Then, the obtained dip-formed body (glove) was evaluated for the presence or absence of cracks, poor appearance, and pinholes, the film thickness and the stress at 500% elongation were measured, and the wearing durability test was performed according to the above method. gone. In this example, after the start of immersion in the first immersion tank and the second immersion tank, the length of time to reach the predetermined deepest position, and the withdrawal from the first immersion tank and the second immersion tank. These evaluations were carried out mainly on the cuff part, which is not easily affected by the length of time. Table 1 shows the results.

<Example 2>
A dip molded body (glove) was produced in the same manner as in Example 1, except that the time for immersing the glove mold to which the coagulant was adhered in the first immersion bath was changed to 8 seconds, and the measurement was performed in the same manner. evaluated and tested. Table 1 shows the results.

<Example 3>
A dip molded body (glove) was produced in the same manner as in Example 1, except that the time for immersing the glove mold to which the coagulant was adhered in the first immersion tank was changed to 16 seconds, and the measurement was performed in the same manner. evaluated and tested. Table 1 shows the results.

<Example 4>
A dip molded article (glove) was produced in the same manner as in Example 1, except that the time for immersing the glove mold with the latex composition attached in the second immersion tank was changed to 6 seconds, and the measurement was performed in the same manner. , evaluated and tested. Table 1 shows the results.

<Example 5>
The time for immersing the glove mold with the coagulant attached in the first immersion bath was changed to 8 seconds, and the time for immersing the glove mold with the latex composition attached in the second immersion bath was changed to 8 seconds. A dip-molded article (glove) was produced in the same manner as in Example 1, except that it was changed to , and measurements, evaluations and tests were performed in the same manner. Table 1 shows the results.

<Example 6>
The time for immersing the glove mold with the coagulant attached in the first immersion bath was changed to 16 seconds, and the time for immersing the glove mold with the latex composition attached in the second immersion bath was changed to 8 seconds. A dip-molded article (glove) was produced in the same manner as in Example 1, except that it was changed to , and measurements, evaluations and tests were performed in the same manner. Table 1 shows the results.

<Comparative Example 1>
In the same manner as in Example 1, except that the time for immersing the glove mold with the coagulant attached in the first immersion tank was changed to 8 seconds, and the immersion in the second immersion tank was not performed. A dip-molded article (glove) was produced and similarly measured, evaluated and tested. Table 1 shows the results.

<Comparative Example 2>
In the same manner as in Example 1, except that the time for immersing the glove mold with the coagulant attached in the first immersion tank was changed to 16 seconds, and the immersion in the second immersion tank was not performed. A dip-molded article (glove) was produced and similarly measured, evaluated and tested. Table 1 shows the results.

<Comparative Example 3>
In the same manner as in Example 1, except that the time for immersing the glove mold with the coagulant attached in the first immersion tank was changed to 24 seconds, and the immersion in the second immersion tank was not performed. A dip-molded article (glove) was produced and similarly measured, evaluated and tested. Table 1 shows the results.

<Comparative Example 4>
The time for immersing the glove mold with the coagulant attached in the first immersion bath was changed to 8 seconds, and the time for immersing the glove mold with the latex composition attached in the second immersion bath was changed to 1 second. A dip-molded article (glove) was produced in the same manner as in Example 1, except that it was changed to , and measurements, evaluations and tests were performed in the same manner. Table 1 shows the results.

<Comparative Example 5>
The time for immersing the glove mold with the coagulant attached in the first immersion bath was changed to 5 seconds, and the time for immersing the glove mold with the latex composition attached in the second immersion bath was changed to 3 seconds. A dip-molded article (glove) was produced in the same manner as in Example 1, except that it was changed to , and measurements, evaluations and tests were performed in the same manner. Table 1 shows the results.

<Comparative Example 6>
The time for immersing the glove mold with the coagulant attached in the first immersion bath was changed to 5 seconds, and the time for immersing the glove mold with the latex composition attached in the second immersion bath was changed to 6 seconds. A dip-molded article (glove) was produced in the same manner as in Example 1, except that it was changed to , and measurements, evaluations and tests were performed in the same manner. Table 1 shows the results.

<Comparative Example 7>
The time for immersing the glove mold with the coagulant attached in the first immersion bath was changed to 8 seconds, and the time for immersing the glove mold with the latex composition attached in the second immersion bath was changed to 16 seconds. A dip-molded article (glove) was produced in the same manner as in Example 1, except that it was changed to , and measurements, evaluations and tests were performed in the same manner. Table 1 shows the results.

<Reference example 1>
except that 1 part colloidal sulfur, 1.5 parts zinc dibutyldithiocarbamate, and 1.5 parts zinc oxide were used in place of sodium aluminate, sorbitol, and sodium glycolate in preparing the latex composition. A latex composition was obtained in the same manner as in Example 1, and the resulting latex composition was divided in half and placed in separate dipping tanks, one being the first dipping tank and the other the second. A dipping tank was used.

Then, as the dipping tanks, the first dipping tank and the second dipping tank are used, and the time for dipping the glove mold to which the coagulant is attached in the first dipping tank is changed to 5 seconds, and the latex composition A dip-molded body (glove) was produced in the same manner as in Example 1, except that the time for immersing the glove mold with the substance attached in the second immersion bath was changed to 6 seconds, and the measurement and evaluation were performed in the same manner. and tested. Table 1 shows the results.

<Reference example 2>
In the same manner as in Reference Example 1, except that the time for immersing the glove mold with the coagulant attached in the first immersion tank was changed to 8 seconds, and the immersion in the second immersion tank was not performed. A dip-molded article (glove) was produced and similarly measured, evaluated and tested. Table 1 shows the results.

As shown in Table 1, using a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber (A) and a metal compound (B) containing a trivalent or higher metal, the immersion in the first immersion step When the time is 8 to 20 seconds and the immersion time in the second immersion step is 3 seconds or more and the immersion time in the first immersion step or less is performed twice, the obtained The dip-molded product does not have any structural defects such as cracks, poor appearance, and pinholes, has a soft texture (low stress at 500% elongation), and has excellent durability. (Examples 1-6).

On the other hand, when the immersion treatment was performed only once, the resulting dip-molded article had pinholes (Comparative Examples 1 to 3).
Also, even if the immersion treatment is performed twice, if the first immersion treatment time is too short, cracks will occur in the resulting dip molded product, and the second immersion treatment time will be too short. In some cases, the resulting dip-molded body will have pinholes, and if the third immersion treatment time is too long, the resulting dip-molded body will have poor appearance and pinholes. As a result, it was shrunk (Comparative Examples 4 to 7).

In addition, as in Reference Examples 1 and 2, when a sulfur-based cross-linking agent and a sulfur-based cross-linking accelerator were used, the immersion treatment was performed once, and the immersion time was set outside the scope of the present invention. However, none of the structural defects such as cracks, poor appearance, and pinholes occurred, and from this, the problems that occurred in Comparative Examples 1 to 7 were solved by using a metal compound containing a trivalent or higher metal as a cross-linking agent. It can be said that this is a peculiar problem when (B) is used.
In Examples 1 to 6, since the metal compound (B) containing a trivalent or higher metal is used as the cross-linking agent, in addition to the immediate type allergy (Type I), delayed type allergy (Type IV ), on the other hand, in Reference Examples 1 and 2, since a sulfur-based cross-linking agent and a sulfur-based cross-linking accelerator were used, delayed allergy (Type IV) occurred. will be lost.

Claims (2)

A method for producing a dip-molded product by dip-molding a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber (A) and a metal compound (B) containing a trivalent or higher metal, comprising:
a first dipping step of adhering the latex composition to the dip mold by dipping the dip mold in the latex composition;
and a second dipping step of dipping the dip mold to which the latex composition is attached in the first dipping step into the latex composition,
The immersion time in the first immersion step is 8 to 20 seconds, the immersion time in the second immersion step is 3 seconds or more and the immersion time in the first immersion step or less ,
A method for producing a dip-molded article, wherein the total time of the immersion time in the first immersion step and the immersion time in the second immersion step is 11 to 27 seconds . 2. The method for producing a dip-formed body according to claim 1, wherein the immersion time in the second immersion step is shorter than the immersion time in the first immersion step by 3 seconds or more.