WO2020066835A1 - Method for manufacturing gloves - Google Patents

Abstract

Provided is a method for manufacturing gloves, comprising: a step for forming a dip-molded layer by dip-molding a latex composition containing a latex of a carboxyl-group-containing conjugated diene rubber (A), a metal compound (B) including an at least divalent metal, and a hindered-phenol-based aging inhibitor (C); and a step for irradiating the dip-molded layer with radiation; wherein the content of the hindered-phenol-based aging inhibitor (C) included in the gloves after irradiation thereof with radiation is 5,000 wt ppm to 70,000 wt ppm.

Description

Glove manufacturing method

The present invention relates to a method for producing gloves, and more particularly, to a method for producing gloves in which coloring is suppressed, tensile strength is high, elongation is high, and a soft texture and a high stress retention are provided.

Conventionally, a dip molded product used in contact with the human body such as a nipple, a balloon, a glove, a balloon, and a sack is known by dip molding a latex composition containing a natural latex represented by a natural rubber latex. I have. However, since natural latex contains a protein that causes allergic symptoms to the human body, there are many problems with dip molded articles, particularly gloves, which come into direct contact with a living mucous membrane or an organ. Therefore, use of synthetic nitrile rubber latex has been studied.

For example, Patent Document 1 contains a latex of a conjugated diene rubber containing a carboxyl group and a metal compound containing a divalent or higher valent metal, and does not substantially contain sulfur and / or a sulfur-containing compound as a crosslinking agent. A glove manufacturing method is disclosed which includes a step of forming a dip-formed layer by dip-forming a latex composition, and a step of irradiating the dip-formed layer with radiation.

According to Patent Literature 1, gloves having high tensile strength, large elongation, a soft touch and a high stress retention rate can be manufactured, but gloves obtained by the manufacturing method described in Patent Literature 1 require radiation irradiation. As a result, there is a problem that coloring occurs and its commercial value is reduced.

WO 2017/146239

The present invention has been made in view of such circumstances, and a method for producing gloves in which occurrence of coloring is suppressed, tensile strength is high, elongation is large, a soft texture and a high stress retention rate are provided. The purpose is to provide.

The present inventors have conducted intensive studies to solve the above-described problems, and as a result of producing a glove by irradiating a radiation to a dip-formed layer obtained by dip-forming the latex composition, as a latex composition. In addition to a latex of a conjugated diene rubber containing a carboxyl group and a metal compound containing a divalent or higher valent metal, a compound containing a hindered phenolic antioxidant is used, and contained in gloves after irradiation. By controlling the content of the hindered phenol-based antioxidant in the range of 5,000 ppm by weight or more and 70,000 ppm by weight or less, it is possible to suppress the occurrence of coloring in the obtained glove, and The resulting glove can have high tensile strength, high elongation, soft texture and high stress retention Found that, it has led to the completion of the present invention.

That is, according to the present invention, it contains a latex of a carboxyl group-containing conjugated diene-based rubber (A), a metal compound containing a divalent or higher-valent metal (B), and a hindered phenol-based antioxidant (C). A step of forming a dip-molded layer by dip-forming the latex composition,
A step of irradiating the dip-formed layer with radiation, comprising:
There is provided a method for producing a glove in which the content of the hindered phenolic antioxidant (C) contained in the glove after irradiation is 5,000 to 70,000 ppm by weight.

In the method for producing gloves of the present invention, it is preferable that the yellowness (YI) indicating the yellow color of the glove after irradiation is 10 or less.
In the method for producing a glove according to the present invention, the content of the hindered phenolic antioxidant (C) in the latex composition is preferably 0.1 part by weight based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A). It is preferable that the amount is in the range of 5 to 8.5 parts by weight, and the irradiation of the dip-formed layer is performed within 40 days after the formation of the dip-formed layer.
In the method for manufacturing a glove according to the present invention, the step of forming the dip-forming layer includes the step of dip-forming the latex composition and then performing a heat treatment to thereby form the metal compound (B) containing the divalent or higher-valent metal. Preferably, it is a step of performing crosslinking.
In the method for producing gloves of the present invention, it is preferable that the hindered phenolic antioxidant (C) is a compound obtained by butylating a condensate of p-cresol and dicyclopentadiene.
In the method for producing gloves of the present invention, it is preferable that the hindered phenolic antioxidant (C) is a compound represented by the following general formula (1).

(In the formula, n represents an integer.)
In the method for producing gloves of the present invention, the latex of the carboxyl group-containing conjugated diene rubber (A) is preferably a latex of a carboxyl group-containing nitrile rubber (a1).
In the method for producing gloves of the present invention, the metal compound (B) containing a divalent or higher valent metal is a metal compound containing a trivalent or higher valent metal, and the latex composition contains a saccharide (d1), a sugar alcohol ( It is preferable that the composition further contains at least one alcoholic hydroxyl group-containing compound (D) selected from d2), a hydroxy acid (d3) and a hydroxy acid salt (d4).

According to the present invention, it is possible to provide a method for producing gloves in which the occurrence of coloring is suppressed, the tensile strength is high, the elongation is large, the texture is soft, and the stress retention is high.

The method for producing gloves of the present invention comprises a latex of a conjugated diene rubber containing a carboxyl group (A), a metal compound containing a divalent or higher valent metal (B), and a hindered phenol antioxidant (C). Forming a dip-formed layer by dip-forming the latex composition to be formed,
A step of irradiating the dip-formed layer with radiation, comprising:
The content of the hindered phenolic antioxidant (C) contained in the glove after irradiation is controlled to 5,000 to 70,000 ppm by weight.

<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), a metal compound containing a divalent or higher valent metal (B), and a hindered phenolic antioxidant (C). Is what you do.

The latex of the carboxyl group-containing conjugated diene rubber (A) may be a copolymer latex 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, a latex of a copolymer obtained by copolymerizing another ethylenically unsaturated monomer copolymerizable therewith, which is used as necessary, may be used.

Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and chloroprene. Can be Of these, 1,3-butadiene is preferred. These conjugated diene monomers can be used alone or in combination of two or more. The content ratio of the conjugated diene monomer unit 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, it is 56 to 70% by weight. By setting the content of the conjugated diene monomer unit to the above range, the glove obtained by the production method of the present invention is made to have an excellent texture and an increased elongation while ensuring sufficient tensile strength. be able to.

Further, among the monomer units derived from the conjugated diene monomer, the monomer unit derived from isoprene may cause softening deterioration due to irradiation with radiation as described below, and thus may be included in the carboxyl group-containing nitrile rubber (a1). The content ratio of the monomer unit derived from isoprene is preferably 5% by weight or less, more preferably 2.5% by weight or less, further preferably 1% by weight or less, and isoprene-derived It is particularly preferred that the monomer unit is not substantially contained. The same reason applies to the latex of the carboxyl group-containing styrene-butadiene rubber (a2), the latex of the carboxyl group-containing butadiene rubber (a3), and the latex of the carboxyl group-containing conjugated diene rubber (A) described later. Thus, the content of monomer units derived from isoprene in these carboxyl group-containing conjugated diene rubbers is preferably 5% by weight or less, more preferably 2.5% by weight or less, and further preferably 1% by weight or less, It is particularly preferred that it does not substantially contain a monomer unit derived from isoprene.

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, a single monomer of ethylenically unsaturated monocarboxylic acid such as acrylic acid and methacrylic acid is used. 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; and the like. Of 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. In addition, the ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. The content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed by the ethylenically unsaturated carboxylic acid monomer 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, still more preferably 2 to 4.5% by weight, particularly preferably 2.5 to 4.5% by weight. By adjusting the content of the ethylenically unsaturated carboxylic acid monomer unit to the above range, the glove obtained by the production method of the present invention has a satisfactory tensile strength while having a sufficient tensile strength, and the elongation is further increased. It can be.

The ethylenically unsaturated nitrile monomer is not particularly limited as long as it is an ethylenically unsaturated monomer containing a nitrile group. For example, acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile And the like. 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 ratio of the ethylenically unsaturated nitrile monomer unit formed by the ethylenically unsaturated nitrile monomer in the carboxyl group-containing nitrile rubber (a1) is preferably from 20 to 40% by weight, more preferably It is 25 to 40% by weight, more preferably 30 to 40% by weight. By setting the content of the ethylenically unsaturated nitrile monomer unit in the above range, the glove obtained by the production method of the present invention has an excellent texture and an increased elongation while ensuring sufficient tensile strength. Things.

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 fluoroethyl vinyl ether; (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide; Ethylenically unsaturated amide monomers such as N-propoxymethyl (meth) acrylamide; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; Trifluoroethyl (meth) acrylate, ( T) tetrafluoropropyl acrylate, dibutyl maleate, dibutyl fumarate, diethyl maleate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, (meth) acrylic acid Cyanomethyl, 2-cyanoethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, 2-ethyl-6-cyanohexyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, ( Ethylenically unsaturated carboxylic acid ester monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, and dimethylaminoethyl (meth) acrylate; divinylbenzene, polyethylene glycol di (meth) Acrylate, And the like; polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, crosslinking monomer, such as pentaerythritol (meth) acrylate. These ethylenically unsaturated monomers can be used alone or in combination of two or more.

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

ラ テ ッ ク ス The latex of the carboxyl group-containing nitrile rubber (a1) can be obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, but a method of copolymerizing by emulsion polymerization is preferable. As the emulsion polymerization method, a conventionally known method can be employed.

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

Examples of the emulsifier include, but are not particularly limited to, nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, and polyoxyethylene sorbitan alkyl ester; potassium dodecylbenzenesulfonate, dodecylbenzene Anionic emulsifiers such as alkylbenzene sulfonates such as sodium sulfonate, higher alcohol sulfates and alkylsulfosuccinates; cationic emulsifiers such as alkyltrimethylammonium chloride, dialkylammonium chloride and benzylammonium chloride; α, β-unsaturated Such as sulfoesters of carboxylic acids, sulfate esters of α, β-unsaturated carboxylic acids, and sulfoalkylaryl ethers Or the like can be mentioned a polymerizable emulsifier. Of these, anionic emulsifiers are preferred, alkylbenzene sulfonates 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 the emulsifier used is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the monomer mixture.

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

The peroxide initiator can be used as a redox polymerization initiator in combination with a reducing agent. The reducing agent is not particularly limited, but 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 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 based on 100 parts by weight of the peroxide.

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

Examples of the method of adding the monomer include a method of adding the monomers used in the reaction vessel all at once, a method of adding the monomers continuously or intermittently according to the progress of the polymerization, and a method of adding a part of the monomers. To a specific conversion, and then the remaining monomer is added continuously or intermittently to carry out polymerization. Either method may be adopted. When the monomers are mixed and added continuously or intermittently, the composition of the mixture may be constant or may vary. Further, each monomer may be added to the reaction vessel after previously mixing various monomers to be used, or may be separately added to the reaction vessel.

Furthermore, if necessary, auxiliary polymerization materials such as a chelating agent, a dispersant, a pH adjuster, a deoxidizer, and a particle size adjuster can be used, and these are not particularly limited in kind or amount.

重合 The polymerization temperature at the time of 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.

乳化 Emulsion polymerization of the monomer mixture as described above, and when a predetermined polymerization conversion is reached, the polymerization system is cooled or a polymerization terminator is added to stop the polymerization reaction. The polymerization conversion when terminating the polymerization reaction is preferably at least 90% by weight, more preferably at least 93% by weight.

Examples of the polymerization terminator include, but are not limited to, hydroxylamine, hydroxyamine sulfate, diethylhydroxylamine, hydroxyaminesulfonic acid and alkali metal salts thereof, sodium dimethyldithiocarbamate, hydroquinone derivatives, catechol derivatives, and hydroxydimethyl Examples include aromatic hydroxydithiocarboxylic acids such as benzenethiocarboxylic acid, hydroxydiethylbenzenedithiocarboxylic acid, and hydroxydibutylbenzenedithiocarboxylic acid, and alkali metal salts thereof. The amount of the polymerization terminator to be used is preferably 0.05 to 2 parts by weight based on 100 parts by weight of the monomer mixture.

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

老 Further, an antioxidant, a preservative, an antibacterial agent, a dispersant, and the like may be appropriately added to the latex of the carboxyl group-containing nitrile rubber (a1) as necessary.

The number average particle diameter of the latex of the carboxyl group-containing nitrile rubber (a1) is preferably from 60 to 300 nm, more preferably from 80 to 150 nm. The particle diameter can be adjusted to a desired value by a method such as adjusting the amounts of the emulsifier and the polymerization initiator.

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

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

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is a carboxyl group-containing ethylenically unsaturated monomer. For example, the same as the above-described latex of the carboxyl group-containing nitrile rubber (a1) Can be used. The content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed by the ethylenically unsaturated carboxylic acid monomer in the carboxyl group-containing styrene-butadiene rubber (a2) is preferably from 2 to 6.5% by weight. , More preferably 2 to 6% by weight, further preferably 2 to 5% by weight, still more preferably 2 to 4.5% by weight, particularly preferably 2.5 to 4.5% by weight. By adjusting the content of the ethylenically unsaturated carboxylic acid monomer unit to the above range, the glove obtained by the production method of the present invention has a satisfactory tensile strength while having a sufficient tensile strength, and the elongation is further increased. It can be.

The content ratio 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, and further preferably 30 to 40% by weight. % By weight. By setting the content of the styrene unit in the above range, the glove obtained by the production method of the present invention can have a good texture and an increased elongation while having a sufficient tensile strength.

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. Other than the same latex as (a1) (excluding styrene), isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and chloroprene And conjugated diene monomers other than 1,3-butadiene. 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 or less. % By weight, more preferably 3% by weight or less.

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

カ ル ボ キ シ ル The carboxyl group-containing styrene-butadiene rubber (a2) latex used in the present invention may optionally contain an antioxidant, a preservative, an antibacterial agent, a dispersant, and the like.

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

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 another ethylenically unsaturated monomer copolymerizable therewith may be used.

The content ratio of the conjugated diene monomer unit 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 to the above range, the glove obtained by the production method of the present invention is made to have an excellent texture and an increased elongation while ensuring sufficient tensile strength. be able to.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is a carboxyl group-containing ethylenically unsaturated monomer. For example, the same as the above-described latex of the carboxyl group-containing nitrile rubber (a1) Can be used. The content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed by the ethylenically unsaturated carboxylic acid monomer in the carboxyl group-containing conjugated diene rubber (a3) is preferably 2 to 10% by weight. It is preferably 2 to 7.5% by weight, more preferably 2 to 6.5% by weight, still 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 adjusting the content of the ethylenically unsaturated carboxylic acid monomer unit to the above range, the glove obtained by the production method of the present invention has a satisfactory tensile strength while having a sufficient tensile strength, and the elongation is further increased. It can be.

Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and chloroprene. As the conjugated diene monomer, any of these may be used alone, or two or more may be used in combination. Of these, 1,3-butadiene is preferred.

Examples of other ethylenically unsaturated monomers copolymerizable with the conjugated diene monomer and the ethylenically unsaturated carboxylic acid monomer include, for example, the same as the above-mentioned latex of the carboxyl group-containing nitrile rubber (a1). (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. Or less, 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-mentioned monomer, but a method of copolymerizing by emulsion polymerization is preferable. As the emulsion polymerization method, the same polymerization auxiliary material as in the case of the carboxyl group-containing nitrile rubber (a1) may be used, and the polymerization may be performed by the same method.

ラ テ ッ ク ス The latex composition used in the present invention contains a metal compound (B) containing a divalent 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 divalent or higher valent metal forms a crosslinked structure by reacting with the carboxyl group contained in the carboxyl group-containing conjugated diene rubber (A) to form a metal ion bond. And thereby act as a crosslinking agent.

The metal compound (B) containing a divalent or higher valent metal is not particularly limited, but may be a zinc compound, a magnesium compound, a titanium compound, a calcium compound, a lead compound, an iron compound, a tin compound, a chromium compound, a cobalt compound, a zirconium compound, Aluminum compounds and the like can be mentioned. These metal compounds (B) containing a divalent or higher metal can be used alone or in combination of two or more. Among these, a metal compound containing a trivalent or higher metal is preferable, and an aluminum compound is particularly preferable, from the viewpoint that the glove obtained by the production method of the present invention can be more excellent in stress retention.

Examples of the aluminum compound include aluminum oxide, aluminum chloride, aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum metal, aluminum ammonium sulfate, aluminum bromide, aluminum fluoride, aluminum / potassium sulfate, aluminum / isopropoxide, and aluminum. Examples thereof include sodium silicate, potassium aluminate, and sodium aluminum sulfite. Of these, sodium aluminate is preferred. These aluminum compounds can be used alone or in combination of two or more.

When a metal compound containing a trivalent or higher valent metal is used as the metal compound containing a divalent or higher valent metal (B), a metal compound containing a divalent metal may be used in combination. By using a metal compound containing a metal together, the tensile strength of the glove obtained by the production method of the present invention can be further increased. When a metal compound containing a trivalent or more metal and a metal compound containing a divalent metal are used in combination, the metal compound containing a divalent metal is preferably a zinc compound, a magnesium compound, a calcium compound, or a lead compound. , A zinc compound is more preferred, and zinc oxide is particularly preferred.

The content ratio of the metal compound (B) containing a divalent or higher valent 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 divalent or higher valent metal in the above range, the cross-linking at the time of cross-linking is made sufficient while the stability as the latex composition is made good. be able to. When a metal compound containing a trivalent or higher metal is used as the metal compound containing a divalent or higher metal (B), the content of the metal compound containing a trivalent or higher metal in the latex composition is as follows: From the viewpoint of the stability and crosslinkability of the latex composition, the content is 0.1 to 1.5 parts by weight based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A) contained in the latex. It is preferably 0.1 to 1.25 parts by weight, more preferably 0.1 to 1.0 part by weight. Furthermore, when a metal compound containing a trivalent or higher valent metal and a metal compound containing a divalent metal are used in combination as the metal compound containing a divalent or higher valent metal (B), the content ratio of the metal compound containing a divalent or higher valent metal is determined by the latex composition From the viewpoint of stability and cross-linkability as a product, the weight ratio of “the metal compound containing a trivalent or higher metal: the metal compound containing a divalent metal” is preferably in the range of 100: 0 to 0: 100, Preferably it is in the range of 10:90 to 90:10.

The latex composition used in the present invention is a hindered phenol-based antioxidant in addition to the latex of the carboxyl group-containing conjugated diene-based rubber (A) and the metal compound containing a divalent or higher valent metal (B). (C) is contained.

The hindered phenolic antioxidant (C) has a phenol structure, and has a bulky group (for example, t-butyl group) at one of the ortho positions of the OH group (phenolic hydroxyl group) constituting the phenol structure. ), And is not particularly limited.

Examples of the hindered phenolic antioxidant (C) include compounds obtained by butylation of a condensate of p-cresol and dicyclopentadiene, 2,6-di-t-butyl-p-cresol, 3-t -Butyl-4-hydroxyanisole, 2-t-butyl-4-hydroxyanisole, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6- t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), n-octadecyl-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate, , 3,5-Tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione, Taerythrityl-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), And tris (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate. Among these, from the viewpoint that the coloration of the obtained glove can be more appropriately suppressed, a compound obtained by butylation of a condensate of p-cresol and dicyclopentadiene (OH group (phenol constituting p-cresol) A compound obtained by butylating the ortho position of the hydroxyl group), and a compound obtained by t-butylating a condensate of p-cresol and dicyclopentadiene (p in the condensate of p-cresol and dicyclopentadiene). -A compound obtained by introducing a t-butyl group into the ortho position of an OH group (phenolic hydroxyl group) constituting cresol) is more preferable, and a compound represented by the following general formula (1) is particularly preferable. The compound represented by the following general formula (1) can be obtained, for example, by obtaining a condensate of p-cresol and dicyclopentadiene and then reacting isobutylene.

(In the formula, n represents an integer.)

In the present invention, a dip-formed layer formed by dip-forming a latex composition containing such a hindered phenol-based antioxidant (C) and dip-forming such a latex composition. To produce gloves by irradiating the gloves, wherein the content of the hindered phenolic antioxidant (C) contained in the gloves after the irradiation is 5,000 ppm by weight or more. , 70,000 ppm by weight or less. And thereby, it is possible to make the resulting glove excellent in the occurrence of coloring, high tensile strength, large elongation, soft texture and high stress retention.

Therefore, in the latex composition used in the present invention, the content of the hindered phenolic antioxidant (C) is determined by the content of the hindered phenolic antioxidant (C) contained in the glove after irradiation. The amount may be within the above range, but the content of the hindered phenol-based antioxidant (C) with respect to 100 parts by weight of the carboxyl group-containing conjugated diene-based rubber (A) in the latex composition used in the present invention. The amount is preferably 0.5 to 8.5 parts by weight, more preferably 0.8 to 7.5 parts by weight, still more preferably more than 1.5 parts by weight, and even more preferably 7.5 parts by weight or less. Is 1.6 to 6.0 parts by weight.

In the latex composition used in the present invention, when a metal compound containing a trivalent or more metal is used as the metal compound containing a divalent or more metal (B), the saccharide (d1), It is preferable that the composition further contains at least one alcoholic hydroxyl group-containing compound (D) selected from alcohol (d2), hydroxy acid (d3) and hydroxy acid salt (d4). By further including such an alcoholic hydroxyl group-containing compound (D), the dispersibility of a metal compound containing a trivalent or higher valent metal in the latex composition can be further increased, and as a result, a latex composition Can have good stability. And as a result, the stress retention of the glove obtained by the manufacturing method of the present invention can be more appropriately increased.

The alcoholic hydroxyl group-containing compound (D) used in the present invention is at least one selected from saccharides (d1), sugar alcohols (d2), hydroxy acids (d3) and hydroxy acid salts (d4). From the viewpoint that the effects of the present invention can be further enhanced, it is preferable to use at least one selected from sugar alcohols (d2) and hydroxy acid salts (d4). When two or more alcoholic hydroxyl group-containing compounds (D) are used in combination, at least one selected from a saccharide (d1) and a sugar alcohol (d2), a hydroxy acid (d3) and a hydroxy acid salt It is preferable to use a combination of at least one selected from (d4), and it is more preferable to use a combination of a sugar alcohol (d2) and a hydroxy acid salt (d4).

The saccharide (d1) is not particularly limited as long as it is a monosaccharide or a polysaccharide in which two or more monosaccharides are linked by a glycosidic bond. For example, erythrose, threose, ribose, lyxose, xylose, arabinose, allose , Tallow, growth, altrose, galactose, idose, erythrulose, xylulose, ribulose, psicose, fructose, sorbose, tagatose and other monosaccharides; trehalose, maltose, isomaltose, cellobiose, gentiobiose, melibiose, lactose, sucrose, palatinose Disaccharides; maltotriose, isomalttriose, panose, cellotriose, manninotriose, solatriose, melezitose, planteose, gentianose, Trisaccharides such as umbelliferose, lactose sucrose and raffinose; homooligosaccharides such as maltotetraose and isomaltetrate; tetrasaccharides such as stachyose, cellotetraose, scorodose, liquinose and panose; maltopentaose and isomaltopentaose Pentasaccharides; hexasaccharides such as maltohexaose and isomaltohexaose; and the like. These may be used alone or in combination of two or more.

The sugar alcohol (d2) may be a monosaccharide or polysaccharide sugar alcohol, and is not particularly limited. Examples thereof include tritol such as glycerin; tetritol such as erythritol, D-threitol, and L-threitol; D-arabinitol; Pentitols such as L-arabinitol, xylitol, ribitol and pentaerythritol; pentaerythritol; hexitols such as sorbitol, D-iditol, galactitol, D-glucitol, mannitol; heptitols such as boreitol and perseitol; D-erythro-D- Octitol such as galacto-octitol; and the like. These may be used alone or in combination of two or more. Among these, hexitol which is a sugar alcohol having 6 carbon atoms is preferable, and sorbitol is more preferable.

The hydroxy acid (d3) may be any carboxylic acid having a hydroxyl group, and is not particularly limited. Examples thereof include glycolic acid, lactic acid, tartronic acid, glyceric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, and γ-hydroxy acid. Aliphatic 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, and serine Hydroxy acids; salicylic acid, creosoteric acid (homosalicylic acid, hydroxy (methyl) benzoic acid), vanillic acid, syringic acid, hydroxypropanoic acid, hydroxypentanoic acid, hydroxyhexanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, hydroxynonanoic acid, Hydroxide Monohydroxys such as acid, hydroxyundecanoic acid, hydroxydododecanoic acid, hydroxytridecanoic acid, hydroxytetradecanoic acid, hydroxypentadecanoic acid, hydroxyheptadecanoic acid, hydroxyoctadecanoic acid, hydroxynonadecanoic acid, hydroxyicosanoic acid, and ricinoleic acid Benzoic acid derivatives, pyrocatechic acid, resorcylic acid, protocatechuic acid, gentisic acid, dihydroxybenzoic acid derivatives such as orseric acid, etc., trihydroxybenzoic acid derivatives such as gallic acid, phenylacetic acid derivatives such as mandelic acid, benzylic acid, atrolactin acid, Aromatic hydroxy acids such as cinnamic acid / hydrocinnamic acid derivatives such as melilotic acid, phloretic acid, coumaric acid, umbellic acid, caffeic acid, ferulic acid, and sinapinic acid; and the like. These may be used alone or in combination of two or more. 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 (d4) is not particularly limited as long as it is a salt of a hydroxy acid, and examples thereof include metal salts of the hydroxy acid exemplified as specific examples of the hydroxy acid (d3). And salts of alkaline earth metals such as calcium and magnesium. As the hydroxy acid salt (d4), one type may be used alone, or two or more types may be used in combination. As the hydroxy acid salt (d4), an alkali metal salt of a hydroxy acid is preferred, and a sodium salt of the hydroxy acid is preferred. The hydroxy acid constituting the hydroxy acid salt (d4) is preferably an aliphatic hydroxy acid, more preferably an aliphatic α-hydroxy acid, and is glycolic acid, lactic acid, tartronic acid, glyceric acid, malic acid, tartaric acid, or citric acid. Acids are more preferred, and glycolic acid is particularly preferred. That is, sodium glycolate is particularly suitable as the hydroxy acid salt (d4).

In the latex composition used in the present invention, the content of the alcoholic hydroxyl group-containing compound (D) is more than that of the metal compound containing a trivalent or higher-valent metal. The amount is preferably in the range of 1: 0.1 to 1:50, more preferably in the range of 1: 0.2 to 1:45, more preferably in the ratio by weight of compound (D). Is an amount ranging from 1: 0.3 to 1:30. By setting the content of the alcoholic hydroxyl group-containing compound (D) in the above range, the stability of the latex composition can be further improved.

The latex composition used in the present invention includes, for example, a latex of a carboxyl group-containing conjugated diene rubber (A), a metal compound containing a divalent or higher valent metal (B), a hindered phenolic antioxidant (C), Further, it can be obtained by blending an alcoholic hydroxyl group-containing compound (D) used as required. The latex of the carboxyl group-containing conjugated diene rubber (A) contains a metal compound containing a divalent or higher valent metal (B), a hindered phenolic antioxidant (C), and optionally contains an alcoholic hydroxyl group. The method for compounding the compound (D) is not particularly limited. However, the metal compound (B) containing a metal having a valency of 2 or more can be favorably dispersed in the obtained latex composition. The metal compound (B) containing the above metal is preferably dissolved in water or alcohol together with the alcoholic hydroxyl group-containing compound (D) used as necessary, and added in the form of an aqueous solution or alcohol solution. The hindered phenolic antioxidant (C) is also in the form of a solution or dispersion dissolved or dispersed in water or alcohol from the viewpoint of improving dispersibility in the obtained latex composition. Is preferably added.

Further, the latex composition used in the present invention includes a latex of the above-mentioned carboxy group-containing conjugated diene rubber (A), a metal compound containing a divalent or higher valent metal (B), and a hindered phenolic antioxidant (C). ), And, in addition to the alcoholic hydroxyl group-containing compound (D) used as necessary, a crosslinking agent other than the metal compound (B) containing a divalent or higher valent metal (B), a filler, a pH adjuster, and a thickener, if desired. , An antioxidant other than the hindered phenolic antioxidant (C), a dispersant, a pigment, a filler, a softener, and the like.

架橋 Examples of the crosslinking agent other than the metal compound (B) containing a divalent or higher valent metal include sulfur and / or a sulfur-containing compound. The sulfur as a cross-linking agent is substantially composed of only sulfur atoms, and is used as a cross-linking agent for cross-linking various rubbers. In particular, carbon-carbon double of a conjugated diene monomer unit is used. Elemental sulfur acting on the binding portion, specific examples of which include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Examples of the sulfur-containing compound as a cross-linking agent include compounds containing a sulfur atom and used for a cross-linking agent for cross-linking various rubbers, particularly, a carbon-carbon double bond of a conjugated diene monomer unit. Compounds acting on moieties, such as sulfur monochloride, sulfur dichloride, 4,4'-dithiodimorpholine, alkylphenol disulfide, 6-methylquinoxaline-2,3-dithiocarbonate, caprolactam disulfide, dibutyl Examples include zinc dithiocarbamate, phosphorus-containing polysulfide, and high-molecular polysulfide.

In the latex composition used in the present invention, the content of sulfur and / or the sulfur-containing compound as a cross-linking agent is based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A) contained in the latex. The total amount of the sulfur-containing compounds is preferably more than 0 parts by weight and 4 parts by weight or less, more preferably more than 0 parts by weight and 2.5 parts by weight or less, still more preferably more than 0 parts by weight and 1.5 parts by weight or less. It is.

ラ テ ッ ク ス The solid content 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 used in the present invention is preferably 7.5 to 12.0, more preferably 7.5 to 11.0, further preferably 7.5 to 9.4, and particularly preferably 7. 5 to 9.2.

<Production method of gloves>
The glove manufacturing method of the present invention includes a step of forming a dip-formed layer by dip-forming the above-described latex composition, and a step of irradiating the formed dip-formed layer with radiation.

In dip molding, a glove-shaped mold (glove mold) is immersed in the latex composition, the latex composition is deposited on the surface of the glove mold, and then the glove mold is pulled up from the latex composition, and then the glove mold is placed on the surface of the glove mold. This is a method of drying the deposited latex composition. The glove mold before dipping in the latex composition may be preheated. Before dipping the glove mold in the latex composition or after lifting the glove mold from the latex composition, a coagulant may be used as necessary.

Specific examples of the method of using the coagulant include a method of dipping a glove mold before dipping in the latex composition into a solution of the coagulant to adhere the coagulant to the glove mold (anode coagulation dipping method), a method of using a latex composition Is immersed in a coagulant solution (teig adhesion immersion method), but the anodic adhesion immersion method is preferred in that a dip-formed layer with less thickness unevenness can be obtained.

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; and acetic acids such as barium acetate, calcium acetate and zinc acetate. Salts; sulfates such as calcium sulfate, magnesium sulfate, and aluminum sulfate; and the like. Of these, calcium chloride and calcium nitrate are preferred.
The coagulant is typically used as a solution in water, alcohol, or a mixture thereof. The coagulant concentration is usually 5 to 50% by weight, preferably 10 to 35% by weight.

(4) Then, the obtained dip-formed layer is subjected to a heat treatment to perform crosslinking with the metal compound (B) containing a divalent or higher-valent metal. The crosslinking at this time proceeds by reacting the metal compound (B) containing a divalent or higher-valent metal with the carboxyl group contained in the carboxyl group-containing conjugated diene rubber (A), thereby forming a metal ion bond. Before the heat treatment, the dip-formed layer is immersed in water, preferably 30 to 70 ° C. for about 1 to 60 minutes to remove water-soluble impurities (eg, excess emulsifier and coagulant). It may be removed. The operation of removing the water-soluble impurities may be performed after the heat treatment of the dip-formed layer, but is preferably performed before the heat treatment because water-soluble impurities can be more efficiently removed.

架橋 The cross-linking of the dip-formed layer with the metal compound (B) containing a divalent or higher valent metal is usually performed by performing a heat treatment at a temperature of 80 to 150 ° C., preferably for 10 to 130 minutes. As a heating method, a method of external heating with infrared rays or heated air or internal heating with high frequency can be adopted. Of these, external heating with heated air is preferred.

Then, the crosslinked dip molding layer is detached from the glove mold to obtain a dip molding before irradiation. As the detaching method, a method of peeling off from the glove mold by hand or a method of peeling off by water pressure or compressed air pressure can be adopted. After the desorption, heat treatment may be further performed at a temperature of 60 to 120 ° C. for 10 to 120 minutes.

Next, the obtained pre-irradiation dip-formed body is irradiated with radiation to obtain gloves (dip-formed body after irradiation). According to the production method of the present invention, the glove obtained by the production method of the present invention is obtained by irradiating the dip-formed layer (dip-formed body before irradiation) formed from the above-described latex composition with radiation. While having a large elongation and a soft texture, the tensile strength can be greatly improved, and further, a high stress holding ratio can be obtained. In particular, gloves obtained by dip molding, such as surgical gloves, have high tensile strength and large elongation, and in addition to this, the feeling of use when wearing and working is important. . Specifically, in addition to the texture (stress at the time of 500% elongation), it is possible to effectively prevent the loosening and the slack from occurring with the lapse of time after the wearing (that is, the tensile stress M100 (100% elongation of the glove)). It is desirable that the stress holding ratio indicated by the percentage of the stress M100 (6) after the elapse of 6 minutes from the stop of the stretching is high with respect to 0). On the other hand, according to the present invention, the glove obtained by the manufacturing method of the present invention has a high tensile strength, a high elongation, and an excellent stress (feel) at the time of elongation of 500%. It can provide a high stress retention.

The reason why the high stress holding ratio can be realized in the production method of the present invention is not necessarily clear, but the conjugated diene of the carboxyl group-containing conjugated diene rubber (A) contained in the latex composition is irradiated by irradiation. It is considered that the carbon-carbon double bond portion of the monomer unit can be crosslinked, and a high stress retention can be realized by forming such a crosslink.

Further, in the production method of the present invention, irradiation of a dip-forming layer (a dip-formed body before irradiation) formed from a latex composition with radiation is included in gloves after irradiation, and a hindered phenol-based anti-aging agent is included. The operation is performed so that the content of the agent (C) is in the range of 5,000 to 70,000 ppm by weight. According to the production method of the present invention, by controlling the content of the hindered phenolic anti-aging agent (C) contained in the glove after irradiation to be in the above range, the coloring of the obtained glove is controlled. Generation, especially coloring due to radiation irradiation can be effectively suppressed. In addition, the content of the hindered phenolic antioxidant (C) contained in the glove after the irradiation is not less than 5,000 wt ppm, not more than 70,000 wt ppm, preferably not less than 9,000 wt ppm, 70,000 wt ppm or less, more preferably 10,000 wt ppm or more, 50,000 wt ppm or less, still more preferably 10,000 wt ppm or more, 30,000 wt ppm or less, still more preferably 15,000 wt ppm. More than 30,000 ppm by weight.

The content of the hindered phenolic antioxidant (C) contained in the glove after irradiation is determined by the content of the hindered phenolic antioxidant (C) contained in the latex composition used for dip molding. A method for controlling the amount within the above range, and, in addition, after obtaining a dip-formed body before irradiation (after performing crosslinking by heating with a metal compound (B) containing a divalent or higher-valent metal), storing When the conditions are at room temperature, a method of irradiating with radiation is preferably performed within 40 days, more preferably within 20 days, further preferably within 10 days. Antioxidants such as hindered phenolic antioxidants (C) often gradually deactivate with storage time after crosslinking by heating. From the viewpoint of suitably controlling the content of the hindered phenolic anti-aging agent (C) contained in the glove later in the above range, the hindered phenol-based aging contained in the latex composition used for dip molding is preferred. It is preferable that the content of the inhibitor (C) be within the above range, and the timing of performing radiation irradiation after obtaining the dip molded body before irradiation be within the above range.

Examples of the radiation to be applied include electromagnetic radiation such as γ-rays and X-rays, and particle radiations such as electron beams and β-rays. The obtained gloves have tensile strength, elongation, stress at 500% elongation, and stress retention. From the viewpoint that the effect of improving the efficiency and the like can be further enhanced, γ-rays or electron beams are preferred, and γ-rays are most preferred. The absorbed dose upon irradiation with radiation such as γ-ray 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 may be set to appropriate conditions in consideration of a target absorbed dose in irradiation of γ-rays or the like and the resistance of the irradiation object to radiation such as γ-rays. desirable. Irradiation energy of γ-rays or the like 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 a radiation source, or cesium 137 is used as radiation source. An energy of 0.66 MeV is sometimes desirable. The irradiation time of γ-rays or the like is not particularly limited because it is a time required for obtaining a target absorbed dose of irradiation of γ-rays or the like.

手袋 Thus, the glove obtained by the production method of the present invention has a suppressed coloring, a high tensile strength, a large elongation, a soft texture and a high stress retention. In particular, the glove obtained by the production method of the present invention has a yellowness (YI; yellow index) indicating a yellow tint, preferably 10 or less, more preferably 8 or less, and still more preferably 7 or less. The occurrence has been appropriately suppressed. The degree of yellowness (YI) can be measured for gloves obtained by the production method of the present invention, for example, using a color difference meter in accordance with JIS K7103.

The glove thus obtained by the production method of the present invention is suitable for gloves used for various applications by utilizing such characteristics, and particularly suitable for surgical gloves.

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

<Amount of hindered phenolic antioxidant>
Approximately 0.5 g of a test piece was cut out from the rubber glove after gamma irradiation obtained in Examples and Comparative Examples, and the weight of the cut out test piece was precisely weighed. The hindered phenolic antioxidant was extracted by Soxhlet extraction under the conditions of 8 hours, and the extract was filtered through a 0.2 μm disk filter. The amount of hindered phenolic antioxidants contained in rubber gloves after gamma irradiation by measuring the amount of phenolic antiaging by reverse phase high performance liquid chromatography (HPLC) under the following conditions: Was measured.
Column: trade name “ZORBOX XDB-C18 1.8μ” (manufactured by Agilent Technologies)
Column temperature: 40 ° C
Flow rate: 0.75 mL / min
Detector: DAD (diode array detection) 280 nm
Injection volume: 2 μL

<Yellowness (YI)>
For the outer surface of the back of the hand of the rubber glove after gamma irradiation obtained in the examples and comparative examples and the rubber glove obtained in the reference example, a color difference meter (product name "SE-2000", Nippon Denshoku Industries Co., Ltd.) Was measured according to JIS K7103.

<Tensile strength, elongation at break, stress at 500% elongation>
A dumbbell (Die-C: manufactured by Dumbbell Ltd.) was used from the rubber glove after gamma irradiation obtained in the examples and comparative examples and the rubber glove obtained in the reference example according to ASTM D-412. A test piece having a shape was prepared. Next, the obtained test piece was pulled at a tensile speed of 500 mm / min, and the tensile strength at break, elongation at break, and stress at 500% elongation were measured. The higher the tensile strength and the elongation at break, the better, and the smaller the stress at 500% elongation, the softer the texture.

<Stress retention>
From the rubber gloves after irradiation in Examples and Comparative Examples and the rubber gloves obtained in Reference Example, a dumbbell shape (Die-C: manufactured by Dumbbell Co.) was used according to ASTM D-412. , A tensile stress is applied to both ends of the test piece at a speed of 500 mm / min. When the standard section 20 mm of the test piece expands twice (100%), the expansion is stopped and the tensile stress M100 (0) was measured, and the tensile stress M100 (6) after elapse of 6 minutes was measured. The percentage of M100 (6) relative to M100 (0) (that is, the percentage of M100 (6) / M100 (0)) was defined as the stress retention. The larger the stress holding ratio, the more difficult it is for sag (looseness or sagging) to occur with the use of gloves.

<Production Example 1 (Production of latex of carboxyl group-containing nitrile rubber (a1-1))>
In a pressure-resistant polymerization reactor equipped with a stirrer, 63 parts of 1,3-butadiene, 34 parts of acrylonitrile, 3 parts of methacrylic acid, 0.25 part of t-dodecylmercaptan as a chain transfer agent, 132 parts of deionized water, sodium dodecylbenzenesulfonate 3 parts, 1 part of sodium formalin condensate of β-naphthalenesulfonic acid, 0.3 part of potassium persulfate, and 0.005 part of sodium ethylenediaminetetraacetate were charged, and polymerization was started at a polymerization temperature of 37 ° C. Then, when the polymerization conversion rate reaches 70%, the polymerization temperature is raised to 43 ° C., and the reaction is continued until the polymerization conversion rate becomes 95%. Thereafter, sodium dimethyldithiocarbamate 0 is used as a polymerization terminator. The polymerization reaction was stopped by adding 1 part. Then, unreacted monomers are distilled off from the obtained latex of the copolymer under reduced pressure, and the solid content concentration and the pH are adjusted to obtain a carboxyl group having a solid content concentration of 40% by weight and a pH of 8.0. A latex of the group-containing nitrile rubber (a1-1) was obtained. The composition of the obtained carboxyl group-containing nitrile rubber (a1-1) was 1,3-butadiene unit 63% by weight, acrylonitrile unit 34% by weight, and methacrylic acid unit 3% by weight.

<Example 1>
(Preparation of latex composition)
To 250 parts of the latex of the carboxyl group-containing nitrile rubber (a1-1) obtained in Production Example 1 (100 parts in terms of the carboxyl group-containing nitrile rubber (a1-1), 100 parts), 0.2 parts of sodium aluminate and 0.1 part of sorbitol. 4 parts and 0.4 parts of sodium glycolate in water, and an aqueous solution of a hindered phenolic antioxidant (trade name "Wingstay L", manufactured by Goodyear Corporation, hinder represented by the following general formula (1)) 2.29 parts (aqueous solution containing 35% by weight of a dophenol-based antioxidant) (0.8 part in terms of a hindered phenol-based antioxidant represented by the following general formula (1)) were added. Then, deionized water was added thereto to adjust the solid content concentration to 30% by weight to obtain a latex composition.

<Manufacture of dip molded body before γ-ray irradiation>
A coagulant aqueous solution was prepared by mixing 30 parts of calcium nitrate, 0.05 parts of polyethylene glycol octyl phenyl ether as a nonionic emulsifier, and 70 parts of water. Next, a ceramic glove mold previously heated to 70 ° C. was immersed in the aqueous solution of coagulant for 5 seconds, pulled up, dried at 70 ° C. for 10 minutes, and allowed to adhere to the glove mold. Was. Then, the glove mold to which the coagulant has been adhered is dipped in the latex composition obtained above for 10 seconds, pulled up, and then dipped in 50 ° C. warm water for 90 seconds to elute water-soluble impurities, A dip molding layer was formed on a glove mold. Next, the glove mold on which the dip molding layer is formed is heat-treated at a temperature of 125 ° C. for 25 minutes to crosslink the dip molding layer, the crosslinked dip molding layer is peeled off from the glove mold, and the dip molded body before γ-ray irradiation is formed. I got

<Production of rubber gloves after gamma irradiation>
The dip-formed body before γ-irradiation obtained above was stored at room temperature for 10 days, and then the dip-formed body before γ-ray irradiation after storage for 10 days was subjected to γ-rays using cobalt 60 as a radiation source. Irradiation was performed 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, with respect to the obtained dip-formed body (glove) after γ-ray irradiation, the amount of hindered phenol-based antioxidant, yellowness (YI), tensile strength, elongation at break, and elongation at 500% Each measurement of stress and stress retention was performed. Table 1 shows the results.

<Example 2>
The amount of the aqueous solution of the hindered phenolic antioxidant (trade name “Wingstay L”, manufactured by Goodyear) was 4.57 parts (1 in terms of the hindered phenolic antioxidant represented by the general formula (1)). Latex composition, a dip molded body before γ-ray irradiation, and a rubber glove after γ-ray irradiation were manufactured and evaluated in the same manner as in Example 1 except that the composition was changed to .6 parts). Table 1 shows the results.

<Example 3>
The amount of the aqueous solution of the hindered phenolic antioxidant (trade name “Wingstay L”, manufactured by Goodyear) was 14.3 parts (5 in terms of the hindered phenolic antioxidant represented by the general formula (1)). Part), a latex composition, a dip-formed body before γ-ray irradiation, and a rubber glove after γ-ray irradiation were produced in the same manner as in Example 1, and evaluated in the same manner. Table 1 shows the results.

<Comparative Example 1>
The amount of the aqueous solution of the hindered phenol antioxidant (trade name “Wingstay L”, manufactured by Goodyear) is 0.71 part (0 in terms of the hindered phenol antioxidant represented by the general formula (1)). .25 parts), a latex composition, a dip-formed body before γ-ray irradiation, and a rubber glove after γ-ray irradiation were produced in the same manner as in Example 1 and evaluated in the same manner. Table 1 shows the results.

<Comparative Example 2>
The amount of the aqueous solution of the hindered phenolic antioxidant (trade name “Wingstay L”, manufactured by Goodyear) was 28.6 parts (10 in terms of the hindered phenolic antioxidant represented by the general formula (1)). Part), a latex composition, a dip-formed body before γ-ray irradiation, and a rubber glove after γ-ray irradiation were produced in the same manner as in Example 1, and evaluated in the same manner. Table 1 shows the results.

<Comparative Example 3>
The amount of the aqueous solution of the hindered phenolic antioxidant (trade name “Wingstay L”, manufactured by Goodyear) was 4.29 parts (1 in terms of the hindered phenolic antioxidant represented by the general formula (1)). .5 parts) except that the latex composition and the pre-gamma-irradiated dip-formed body were manufactured in the same manner as in Example 1, and the storage period of the pre-gamma-irradiated dip-formed body was changed to 50 days. A rubber glove after γ-irradiation was manufactured and evaluated in the same manner as in Example 1 except for the above. Table 1 shows the results.

<Reference Example 1>
Using the latex composition obtained in the same manner as in Example 1, a dip-formed body before γ-ray irradiation was obtained in the same manner as in Example 1, and this was used as a rubber glove to obtain yellowness (YI), tensile strength, Each of elongation at break, stress at 500% elongation, and stress retention was measured. That is, in Reference Example 1, a rubber glove was obtained in the same manner as in Example 1 except that γ-ray irradiation was not performed. Table 1 shows the results.

<Reference Example 2>
Using the latex composition obtained in the same manner as in Example 2, a dip-formed body before γ-ray irradiation was obtained in the same manner as in Example 2, and this was used as a rubber glove to obtain yellowness (YI), tensile strength, Each of elongation at break, stress at 500% elongation, and stress retention was measured. That is, in Reference Example 2, a rubber glove was obtained in the same manner as in Example 2, except that γ-ray irradiation was not performed.

<Reference Example 3>
Using the latex composition obtained in the same manner as in Comparative Example 2, a dip molded body before γ-irradiation was obtained in the same manner as in Comparative Example 2, and this was used as a rubber glove to obtain yellowness (YI), tensile strength, Each of elongation at break, stress at 500% elongation, and stress retention was measured. That is, in Reference Example 3, a rubber glove was obtained in the same manner as in Comparative Example 2 except that γ-ray irradiation was not performed.

As shown in Table 1, a latex containing a latex of a carboxyl group-containing conjugated diene-based rubber (A), a metal compound containing a divalent or higher valent metal (B), and a hindered phenol-based antioxidant (C) A glove is manufactured by irradiating a radiation to a dip-formed layer obtained by dip-forming the composition, and the content of the hindered phenolic antioxidant (C) contained in the glove after the radiation is determined. When the content is controlled at 5,000 ppm or more and 70,000 ppm or less, the resulting glove has a low yellowness (YI), is suppressed from coloring, and has a high tensile strength. , High elongation, soft texture and high stress retention (Examples 1-3).
Further, as is clear from the comparison between Example 1 and Reference Example 1 and the comparison between Example 2 and Reference Example 2, according to the production method of the present invention, the yellowness (YI) before and after γ-ray irradiation was measured. ) Is small, and it can be confirmed that the occurrence of coloring due to γ-ray irradiation is effectively suppressed.

On the other hand, when the content of the hindered phenolic anti-aging agent (C) contained in the glove after irradiation is less than 5,000 ppm by weight, the yellowness (YI) becomes high and coloring occurs. Was remarkable (Comparative Examples 1 and 3).
When the content of the hindered phenolic antioxidant (C) exceeds 70,000 ppm by weight, the yellowness (YI) can be kept low, while the glove obtained has low tensile strength and elongation. And the texture and stress retention were poor (Comparative Example 2).

Claims (8)

1. Dip-forming a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber (A), a metal compound containing a divalent or higher valent metal (B), and a hindered phenolic antioxidant (C). A step of forming a dip molding layer,
   A step of irradiating the dip-formed layer with radiation, comprising:
   A method for producing gloves, wherein the content of the hindered phenolic antioxidant (C) contained in the glove after irradiation is 5,000 to 70,000 ppm by weight.
2. The method for producing gloves according to claim 1, wherein the yellowness (YI) indicating yellowishness of the gloves after irradiation is 10 or less.
3. In the latex composition, the content of the hindered phenolic antioxidant (C) is in the range of 0.5 to 8.5 parts by weight based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber (A). age,
   The method for producing a glove according to claim 1 or 2, wherein the irradiation of the dip-formed layer with radiation is performed within 40 days after the formation of the dip-formed layer.
4. The step of forming the dip-forming layer is a step of dip-forming the latex composition and then performing a heat treatment to crosslink with the metal compound (B) containing the divalent or higher-valent metal. 4. The method for producing a glove according to any one of items 1 to 3.
5. The method for producing gloves according to any one of claims 1 to 4, wherein the hindered phenolic antioxidant (C) is a compound obtained by butylating a condensate of p-cresol and dicyclopentadiene.
6. The method for producing gloves according to claim 5, wherein the hindered phenolic antioxidant (C) is a compound represented by the following general formula (1).
   

   

   (In the formula, n represents an integer.)
7. The method for producing gloves according to any one of claims 1 to 6, wherein the latex of the carboxyl group-containing conjugated diene rubber (A) is a latex of a carboxyl group-containing nitrile rubber (a1).
8. The metal compound containing a divalent or higher valent metal (B) is a metal compound containing a trivalent or higher valent metal,
   The latex composition further comprises at least one alcoholic hydroxyl group-containing compound (D) selected from saccharides (d1), sugar alcohols (d2), hydroxy acids (d3) and hydroxy acid salts (d4). Item 8. The method for producing a glove according to any one of Items 1 to 7.