JP2003192993A - Coating agent for dip-molded article and dip-molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating agent for a dip-molded article capable of giving a dip-molded article which is easily releasable from a hand mold, excellent in blocking resistance and easy to get on and off and hardly suffers from powder-dropping, and a dip-molded article coated with the coating agent. <P>SOLUTION: The coating agent for a dip-molded article comprises an organic polymer fine particle and a polymer latex, where the polymer constituting the organic polymer fine particle has a glass transition temperature of 40-120°C, a flow initiation temperature of 90-270°C and the flow initiation temperature is higher than the glass transition temperature by 20-200°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating agent for a dip-molded article and a dip-molded article, more specifically, easy release from a hand mold and excellent in blocking resistance.
The present invention relates to a coating agent for a dip-molded article that can be easily attached and detached and that is capable of producing a powder-removed dip-molded article, and a dip-molded article coated with the coating agent.

[0002]

2. Description of the Related Art Typical examples of dip-molded articles made of natural rubber latex or synthetic rubber latex include rubber gloves and finger cots. The inner surface of these rubber gloves is sticky, so they are hard to slip,
It is difficult to put on and take off. Various modifications have been made to these rubber gloves so that they can be easily put on and taken off. That is, in general, in order to prevent tackiness, a method of spraying powder such as talc on the inner surface of the glove or a method of forming irregularities on the inner surface of the glove by chlorination treatment is performed. . However, in the method of spraying the powder, the powder falls off from the gloves during attachment / detachment or during wearing. Therefore, when this type of rubber glove is used for medical gloves (surgical gloves), The surgical site may become contaminated resulting in post-operative infection. Further, the chlorination treatment has problems that the process is difficult to control, the detachability is not sufficiently improved, and that chlorine is used, so that the load on the environment is large.

Alternatively to these methods, by forming an elastomeric layer containing particulates on the inside of the glove,
The device is designed to enhance the putting on and taking off of gloves. For example, Japanese Patent Publication No. 60-6655 proposes a medical glove in which an elastomer layer containing a carboxylated styrene-butadiene latex in which starch particles are dispersed as a main component is formed.

Further, Japanese Patent Application Laid-Open No. 11-61527 proposes a rubber glove in which an elastomer layer is formed by an aqueous dispersion liquid containing a synthetic rubber latex and an organic filler which are not coagulated by a coagulant contained in the glove body. Examples of the synthetic rubber latex include styrene-butadiene rubber latex and acrylonitrile-butadiene rubber latex, and examples of the organic filler include crosslinked methyl methacrylate polymer particles and urethane resin particles.

Further, Japanese Patent Application Laid-Open No. 8-249430 proposes a rubber glove in which an elastomer layer containing thermoplastic resin particles, rubber latex and blocked isocyanate as a main component is formed. As the rubber latex, natural rubber latex, Examples of the chloroprene rubber latex and the thermoplastic resin particles include ethylene-acrylic acid copolymer resin particles and ethylene-methacrylic acid copolymer particles.

In the methods described in these publications, although the detachability is improved to some extent, there is a problem that the insides of the gloves stick to each other and are difficult to peel off. Further, in all cases, the gloves having the elastomer layer formed on the outside are turned over and released from the hand mold to manufacture rubber gloves having the elastomer layer on the inside. However, in such a method, since the frictional force when the elastomer layers rub against each other during release is large, it is difficult to release the mold, and in particular, in order to improve productivity, the mold release is performed at a high hand mold temperature. If it is tried, there is a problem that it becomes more difficult to release the mold.

[0007]

In view of the above circumstances, an object of the present invention is to produce a dip-molded product which is easy to release from a hand mold, has excellent blocking resistance, is easy to put on and take off, and is hard to drop powder. It is intended to provide a coating agent for a dip molded article and a dip molded article obtained by coating the coating agent.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies to achieve the above object, and as a result, in a coating agent containing organic polymer fine particles and a polymer latex, a glass in a specific temperature range was used. It has been found that the above object can be achieved by using organic polymer fine particles having a transition temperature and a flow starting temperature, and a polymer having a difference between the glass transition temperature and the flow starting temperature in a specific range. The present invention has been completed based on the findings.

Thus, according to the present invention, there is provided a coating agent for a dip molded article containing organic polymer fine particles and polymer latex, wherein the polymer constituting the organic polymer fine particles has a glass transition temperature of 40 to 40. Provided is a coating agent for a dip-molded article, which is 120 ° C., the flow starting temperature is 90 to 270 ° C., and the flow starting temperature is 20 to 200 ° C. higher than the glass transition temperature. Further, according to the present invention, there is provided a dip-molded article coated with the coating agent.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. Organic Polymer Fine Particles The polymer constituting the organic polymer fine particles used in the present invention is
Glass transition temperature is 40 to 120 ° C, flow starting temperature is 90
˜270 ° C., and the flow initiation temperature is 20 to 200 ° C. higher than the glass transition temperature.

The glass transition temperature of the polymer is 40 to 120.
C, preferably 45 to 95 C, more preferably 50 to 9
It is 0 ° C. If the glass transition temperature is too low, it will be difficult to release from the hand mold and the blocking resistance will be poor, and if it is too high, powder will easily fall off.

The flow starting temperature of the polymer is 90 to 270.
℃, preferably 95-250 ℃, more preferably 100
~ 230 ° C. If the flow starting temperature is too low, it will be difficult to release from the hand mold, and if too high, powder will easily fall off.

The flow starting temperature is measured as follows. The dried organic polymer fine particles were mixed with a bottom area of 1 cm ² ,
A sample is formed by compression molding into a cylindrical body having a height of about 1 cm. Shimadzu Flow Tester CFT-500C
(Manufactured by Shimadzu Corporation) with a piston applied with a test load of 10 kgf while heating at a temperature rising rate of 3 ° C./min.
Extrude through a die with a die diameter of 0.5 mm and a die length of 1 mm.
/ 2 method.

The flow initiation temperature of the polymer is 20 to 200 ° C., preferably 40 to 180 ° C., above the glass transition temperature.
high. If this difference is too small, it will be difficult to release from the hand mold, and conversely if it is too large, powder will easily fall off.

The monomer which can be used for producing the organic polymer fine particles is not particularly limited, but a conjugated diene monomer, an aromatic vinyl monomer, an ethylenically unsaturated nitrile monomer and an ethylenic unsaturated monomer are used. Examples thereof include saturated carboxylic acid ester monomers, ethylenically unsaturated carboxylic acid monomers, ethylenically unsaturated carboxylic acid amide monomers, and crosslinkable monomers.

As the conjugated diene monomer, for example, 1,
3-butadiene, isoprene, 2,3-dimethyl-1,
3-butadiene, 1,3-pentadiene, chloroprene and the like can be mentioned. Among these, 1,3-butadiene is preferable. Conjugated diene-based monomer, for all monomers,
Usually, it is used in the range of 20% by weight or less, preferably 10% by weight or less. If this amount is too large, blocking resistance tends to deteriorate.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, chlorostyrene, hydroxymethylstyrene and the like.

Examples of the ethylenically unsaturated nitrile monomer include (meth) acrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile and the like. The ethylenically unsaturated nitrile monomer is usually used in the range of 0 to 50% by weight, preferably 0 to 40% by weight, based on the total monomers. If this amount is too large, powder tends to fall off.

Examples of the ethylenically unsaturated carboxylic acid ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
Butyl (meth) acrylate, (meth) acrylic acid-2-
Ethylhexyl, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, cyanomethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate , (Meth) acrylic acid ester such as 2-hydroxyethyl (meth) acrylate and glycidyl (meth) acrylate; ethylenically unsaturated polycarboxylic acid ester such as dibutyl maleate, dibutyl fumarate and diethyl maleate; Can be mentioned.
The amount of the ethylenically unsaturated carboxylic acid ester monomer used is not particularly limited.

Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; ethylene such as fumaric acid, maleic acid, itaconic acid and butenetricarboxylic acid. Unsaturated polycarboxylic acid; monoethyl maleate,
Partial esterified products of ethylenically unsaturated polyvalent carboxylic acids such as monomethyl itaconate may be mentioned.

Examples of the ethylenically unsaturated carboxylic acid amide monomer include (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide and N-methoxymethyl (meth).
Examples include acrylamide.

The crosslinkable monomer is a compound having at least 2, preferably 2 to 4, radically polymerizable carbon-carbon double bonds. Specific examples thereof include polyvalent vinyl aromatic compounds such as diisopropenylbenzene and divinylbenzene; unsaturated ester compounds of α, β-ethylenically unsaturated carboxylic acid such as vinyl acrylate, vinyl methacrylate and allyl methacrylate; Unsaturated ester compounds of polyvalent carboxylic acids such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate and triallyl trimellitate; unsaturated of polyhydric alcohols such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and propylene glycol dimethacrylate. Ester compounds: 1,2-polybutadiene, divinyl ether, divinyl sulfone, N, N'-m-phenylene maleimide and the like. In addition, ethylene glycol, propylene glycol, butanediol,
Hexanediol, neopentyl glycol, aliphatic or aromatic diols such as bisphenol A; 2 to 2
Polyethylene glycol having 0, preferably 2 to 8 oxyethylene units; polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol; and unsaturated fatty acids such as maleic acid, fumaric acid, and itaconic acid An unsaturated polyester compound produced from a polycarboxylic acid may be mentioned. Among these, divinylbenzene is preferable. Divinylbenzene has an ortho-form, a meta-form and a para-form, and may be used alone or in a mixture thereof.

The amount of the crosslinkable monomer used is preferably 0.1 to 7% by weight, more preferably 0.1% by weight, based on all the monomers.
It is 2 to 5% by weight. By adjusting the amount of the crosslinkable monomer used, the difference between the flow initiation temperature and the glass transition temperature in the polymer constituting the organic polymer fine particles can be adjusted within a desired range.

The polymer constituting the fine particles of the organic polymer is not particularly limited. For example, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, styrene- (meth) acrylic acid ester copolymer, (meth) Acrylic ester (co) polymer, polyolefin, polyamide, polyester, phenol resin, etc. can be used. Of these, styrene- (meth) acrylic acid ester copolymers and (meth) acrylic acid ester (co) polymers are preferable, and styrene- (meth) acrylic acid is preferable, because they have an excellent balance between blocking resistance and powder falling resistance. Acid ester copolymers are more preferred. The styrene- (meth) acrylic acid ester copolymer is preferably a styrene-butyl acrylate copolymer, and the (meth) acrylic acid ester (co) polymer is a methyl methacrylate-butyl acrylate copolymer. preferable.

In the case of styrene-butyl acrylate copolymer, styrene is preferably used in an amount of 50 to 98% by weight, more preferably 60 to 9%, based on the total amount of monomers.
5% by weight, butyl acrylate is preferably 1.9-43
% By weight, more preferably 4.8 to 35% by weight, the crosslinkable monomer is preferably 0.1 to 7% by weight, more preferably 0.2 to 5% by weight and the other monomer is preferably 0.
It is from 10 to 10% by weight, more preferably from 0 to 5% by weight. In the case of a methyl methacrylate-butyl acrylate copolymer,
The amount of each monomer used with respect to all monomers is preferably 50 to 98% by weight of methyl methacrylate, and more preferably 6%.
0 to 95% by weight, butyl acrylate is preferably 1.9
To 43% by weight, more preferably 4.8 to 35% by weight, the crosslinkable monomer is preferably 0.1 to 7% by weight, more preferably 0.2 to 5% by weight and other monomers are preferable. Is 0 to 10% by weight, more preferably 0 to 5% by weight.

The organic polymer fine particles are usually produced by suspension polymerization, and preferably produced by polymerizing the above-mentioned monomers in an aqueous medium in the presence of a dispersant.

Water is usually used as the aqueous medium, and it may contain a water-soluble organic solvent such as methanol or ethanol. Especially, it is preferable to use only water. The amount of the aqueous medium used is usually 100 to 1000 parts by weight, preferably 200 to 50 parts by weight, relative to 100 parts by weight of the monomer.
0 parts by weight.

As the dispersant, for example, cellulose derivatives such as hydroxyalkyl cellulose and carboxymethyl cellulose; starch derivatives such as carboxymethyl starch and oxidized starch; gum arabic, transgant gum, polyalkylene glycol and polyvinyl alcohol are used. Of these, polyvinyl alcohol is preferable.
The polyvinyl alcohol has a saponification degree of 80 to 98.
Those having a mol% and an average degree of polymerization of 100 to 3000 are preferable, and those having a saponification degree of 85 to 90 mol% and a viscosity degree of polymerization of 300 to 1500 are more preferable.

The amount of the dispersant used is usually 0.5 to 50 parts by weight, preferably 1 to 2 with respect to 100 parts by weight of the monomer.
It is 0 part by weight, more preferably 1 to 10 parts by weight.

The method of using the dispersant is not particularly limited, but the dispersant may be added to the polymerization reactor in advance, or a part of the dispersant may be added to the polymerization reactor to start the polymerization reaction, and then the balance is left. It can be added to the polymerization reactor.

The method of adding the monomer is not particularly limited, but after the monomer is added to the polymerization reactor in advance or a part of the monomer is added to the polymerization reactor to start the polymerization reaction. , The rest can be added to the polymerization reactor.

As the polymerization initiator used for polymerizing the above-mentioned monomers, those usually used in suspension polymerization can be used. Examples of the polymerization initiator include oil-soluble peroxides such as t-butyl hydroperoxide, benzoyl peroxide, and di-t-butyl peroxide; azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobis-2. , Oil-soluble azo compounds such as 4-dimethylvaleronitrile; and the like. Of these, oil-soluble peroxides are preferable. The amount of the polymerization initiator used is usually 0.1 to 10 relative to 100 parts by weight of the monomer.
Parts by weight, preferably 0.5 to 5 parts by weight.

The method of adding the polymerization initiator is not particularly limited, but after the entire amount is added to the polymerization reactor before the initiation of the polymerization or a part of the polymerization initiator is introduced into the polymerization reactor before the initiation of the polymerization, The balance can be added at a specific time, or a part of the mixture can be added to the polymerization reactor before the start of polymerization to start the polymerization, and then the balance can be continuously or intermittently added to the polymerization reaction system.

In the polymerization, a chain transfer agent may be used, though it is not essential. As the chain transfer agent, for example,
Mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-stearyl mercaptan; mercaptos such as thioglycolic acid, thiomalic acid and 2-ethylhexyl thioglycolate. Compounds having a group; xanthogen compounds such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide; α-methylstyrene dimer, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-methyl-2 -Α-methylstyrene dimers such as pentene and 1,1,3-trimethyl-3-phenylindane; dichloromethane,
Halogenated hydrocarbons such as dibromomethane, carbon tetrachloride and carbon tetrabromide; vinyl ethers such as α-benzyloxystyrene, α-benzyloxyacrylonitrile and α-benzyloxyacrylamide; triphenylethane, pentaphenylethane and the like. . When a chain transfer agent is used, its amount is usually 0.01 to 5 parts by weight with respect to 100 parts by weight of the monomer.

The method of adding the chain transfer agent is not particularly limited and may be added all at once or intermittently or continuously to the polymerization reaction system.

A preferred method for producing the organic polymer fine particles in the present invention is to mix a solution prepared by mixing a monomer, a polymerization initiator and optionally a chain transfer agent with an aqueous solution of a dispersant, and then disperse the mixture. It is a method of making a fine dispersion using a machine, then adding the whole amount of the fine dispersion to a polymerization reaction vessel, and then initiating the polymerization at a desired temperature.

Examples of the disperser include homodispers, ultrasonic dispersers, dyno mills and ring mills.

The polymerization temperature is not particularly limited, but usually 0 to
The temperature is 150 ° C, preferably 50 to 100 ° C.

After the desired polymerization conversion rate is reached, the polymerization is stopped. The termination of the polymerization can be performed by adding a polymerization terminator or simply by cooling the polymerization reaction system. The polymerization conversion rate when terminating the polymerization is preferably 90.
The content is at least wt%, more preferably at least 93 wt%, and particularly preferably at least 95 wt%. After stopping the polymerization, unreacted monomers may be removed, if desired.

The organic polymer fine particles used in the present invention include:
If necessary, an auxiliary agent such as a chelating agent, a dispersion auxiliary agent, a pH adjusting agent, a preservative, a plasticizer, an antifoaming agent may be used together during or after the polymerization.

The aqueous dispersion in which the organic polymer fine particles obtained by the above method are dispersed in an aqueous medium is subjected to filtration, centrifugation, etc. to remove the aqueous medium, and further dried to obtain only the organic polymer fine particles. May be taken out.

The volume average particle diameter of the organic polymer fine particles is usually 1 to 50 μm, preferably 2 to 30 μm, more preferably 3 to 20 μm.

The shape of the organic polymer fine particles is not particularly limited, and organic polymer fine particles having an irregular shape, a dulma shape, an irregular shape, or a spherical shape can be used, but a spherical shape is preferable.

Polymer Latex The polymer latex used in the present invention is not particularly limited, but those produced by emulsion polymerization can be used. Among them, in an aqueous medium, a surfactant or a dispersant (hereinafter,
Both are collectively referred to as a “dispersion stabilizer”. The polymer latex obtained by polymerizing a monomer in the presence of 1) is preferable, and the polymer latex obtained by polymerizing a monomer in the presence of a dispersant in an aqueous medium is more preferable.

Water is usually used as the aqueous medium, and it may contain a water-soluble organic solvent such as methanol or ethanol. The amount of the aqueous medium used is usually 50 to 600 parts by weight, preferably 100 to 4 parts by weight, based on 100 parts by weight of the monomer.
It is 00 parts by weight.

As the surfactant, for example, sulfuric acid ester of higher alcohol, alkylbenzene sulfonate,
Anionic surfactants such as aliphatic sulfonates, polyoxyethylene alkylaryl sulfonates, polyphosphates; examples of nonionic surfactants are nonionic surfactants such as alkyl esters of polyethylene glycol or alkyl phenyl ethers. Activator: Cationic surfactant such as aliphatic amine salt or its quaternary ammonium salt, aromatic quaternary ammonium salt, heterocyclic quaternary ammonium salt; carboxybetaine, sulfobetaine, aminocarboxylic acid salt, imidazoline derivative, etc. And amphoteric surfactants. These emulsifiers may be used alone or in combination of two or more kinds. The amount of these surfactants used is usually 0.1 per 100 parts by weight of the monomer.
10 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

As the dispersant, those mentioned above can be used. Of these, polyvinyl alcohol is preferable. The saponification degree of polyvinyl alcohol is preferably 40 to 100 mol%, more preferably 50 to 99 mol%, and further preferably 70 to 98 mol%. The average degree of polymerization of polyvinyl alcohol is usually 50 to 8,000, preferably 100 to 6,000, more preferably 100 to 6,000.
It is 5,000.

The amount of the dispersant used is usually 0.5 to 100 parts by weight, preferably 1 to 100 parts by weight, based on 100 parts by weight of the monomer.
50 parts by weight, more preferably 1 to 20 parts by weight.

When a dispersant is used, the amount of the surfactant used is preferably 0.5 part by weight or less, and 0.05 part by weight or less, based on 100 parts by weight of the monomer. Are more preferably used, and particularly preferably not used. If the amount used is too large, the blocking resistance tends to deteriorate.

As the monomers that can be used for producing the polymer latex, those listed for producing the organic polymer fine particles can be used.

The polymer constituting the polymer latex is not particularly limited, but examples thereof include styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, styrene- (meth) acrylic acid ester copolymer, and (meth) acrylic. An acid ester (co) polymer or the like can be used. Among them, styrene- (meth) acrylic acid ester copolymers and (meth) acrylic acid ester (co) polymers are preferable, and (meth) acrylic acid ester, from the viewpoint of excellent balance between blocking resistance and powder falling resistance. (Co) polymers are more preferred. The styrene- (meth) acrylic acid ester copolymer is preferably a styrene-butyl acrylate copolymer, and the (meth) acrylic acid ester (co) polymer is a methyl methacrylate-butyl acrylate copolymer. preferable.

In the case of a styrene-butyl acrylate copolymer, styrene is preferably used in an amount of 10 to 60% by weight, more preferably 20 to 5 by weight, based on the total amount of monomers.
0% by weight, butyl acrylate is preferably 40 to 90% by weight, more preferably 50 to 80% by weight, and other monomers are 0 to 20% by weight, preferably 0 to 10% by weight.
Is.

In the case of a methyl methacrylate-butyl acrylate copolymer, the amount of each monomer used relative to all monomers is
Methyl methacrylate is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and butyl acrylate is preferably 40 to 90% by weight, more preferably 50 to 80%.
%, And other monomers are preferably 0 to 20% by weight, more preferably 0 to 10% by weight.

The method of using the dispersion stabilizer is not particularly limited, but the dispersion stabilizer may be added in advance to the polymerization reactor,
After a part of the dispersion stabilizer is added to the polymerization reactor to start the polymerization reaction, the rest is added to the polymerization reactor, or the dispersion stabilizer is continuously or intermittently added at the same time as the start of the polymerization reaction. It can be added to the polymerization reactor.

The method of adding the monomer is not particularly limited, but after the monomer is added to the polymerization reactor in advance or a part of the monomer is added to the polymerization reactor to start the polymerization reaction. The balance can be added to the polymerization reactor, or the monomer can be continuously or intermittently added to the polymerization reactor at the same time as the start of the polymerization reaction. Above all, a method of continuously adding the monomer to the polymerization reactor at the same time as the start of the polymerization reaction is preferable.

The method of adding the monomer and the dispersion stabilizer is not particularly limited, but they may be added separately, or the monomer,
It can be added in the form of a monomer emulsion obtained by mixing a dispersion stabilizer and water. When the monomer and the dispersion stabilizer are added separately, it is preferable to start the addition of both at substantially the same time, and it is preferable to finish the addition of both at almost the same time. Among them, a method of continuously adding to a polymerization reactor in the form of a monomer emulsion obtained by mixing a monomer, a dispersion stabilizer and water is preferable.

The addition rate in the case of continuously adding the monomers is not particularly limited, but it is preferable to control so as to keep the polymerization conversion rate during the reaction at 10% by weight or more. A preferable polymerization conversion rate during the reaction is 20% by weight or more, and more preferably 30% by weight or more. If the addition rate of the monomer is too fast, the polymerization conversion rate becomes low, and coarse particles are likely to occur.

As the polymerization initiator used for polymerizing the above-mentioned monomers, those usually used in emulsion polymerization can be used. Specific examples of the polymerization initiator include water-soluble peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide; oil-soluble peroxides such as t-butyl hydroperoxide, benzoyl peroxide and di-t-butyl peroxide. Oxides; redox initiators obtained by combining peroxides with various reducing agents such as sodium bisulfite can be mentioned. Of these, water-soluble peroxides are preferable, and persulfates are more preferable. The amount of the polymerization initiator used is usually 0.05 with respect to 100 parts by weight of the monomer.
-3 parts by weight, preferably 0.1-2 parts by weight.

The method of adding the polymerization initiator is not particularly limited, but after the whole amount is added to the polymerization reactor before the initiation of the polymerization or a part of the polymerization initiator is introduced into the polymerization reactor before the initiation of the polymerization, The balance can be added at a specific time, or a part of the mixture can be added to the polymerization reactor before the start of polymerization to start the polymerization, and then the balance can be continuously or intermittently added to the polymerization reaction system.

When polyvinyl alcohol is used as the dispersion stabilizer in the above-mentioned method for producing a polymer latex, it is preferable to carry out the polymerization in the presence of alcohol. The alcohol that can be used in this case is not particularly limited, but monohydric or polyhydric water-soluble alcohols are preferable. Specific examples of such alcohol include, for example,
Methanol, ethanol, propanol, butanol,
Examples thereof include ethylene glycol, propylene glycol and glycerol. The amount of alcohol used is usually 1 to 50 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the monomer.

The method of adding the alcohol is not particularly limited, but the whole amount is added to the polymerization reactor before the initiation of the polymerization, or a part of the alcohol is added to the polymerization reactor before the initiation of the polymerization to initiate the polymerization, and then the remaining portion is left. It may be added at a specific time, or a part thereof may be charged into the polymerization reactor before the start of the polymerization to start the polymerization, and the rest may be continuously or intermittently added to the polymerization reaction system. Among them, the method of adding the whole amount to the polymerization reactor before the initiation of the polymerization is preferable.

In the polymerization, a chain transfer agent may be used, though it is not essential. As the chain transfer agent, the above-mentioned ones can be used. The amount of chain transfer agent used is 100
It is usually 0.01 to 5 parts by weight with respect to parts by weight. The method of adding the chain transfer agent is not particularly limited and may be added all at once or intermittently or continuously to the polymerization reaction system.

The polymerization temperature is not particularly limited, but is usually 0.
~ 100 ° C, preferably 50-95 ° C.

After the predetermined polymerization conversion rate is reached, the polymerization is stopped. The termination of the polymerization can be performed by adding a polymerization terminator or simply by cooling the polymerization reaction system. The polymerization conversion rate when terminating the polymerization is preferably 90.
The content is at least wt%, more preferably at least 93 wt%, and particularly preferably at least 95 wt%. After stopping the polymerization, unreacted monomers may be removed, if desired.

The polymer latex used in the present invention includes
If necessary, an auxiliary agent such as a chelating agent, a dispersant, a pH adjuster, an antiseptic, a plasticizer and an antifoaming agent may be used together during or after the polymerization.

The glass transition temperature of the polymer constituting the polymer latex is not particularly limited, but is usually -40 to 3
It is 0 ° C., preferably −20 to 20 ° C. If the glass transition temperature is too low, the blocking resistance tends to decrease.On the contrary, if it is too high, the coating layer may crack when the dip molded product is stretched, and the coating layer may peel off from the dip molded product body. is there.

The volume average particle diameter of the polymer latex is usually 0.01 to 2 μm, preferably 0.05 to 1 μm. If the particle size is too small, the viscosity tends to increase during polymerization and handling becomes difficult. On the contrary, if the particle size is too large, it becomes difficult to obtain a uniform coating layer.

Coating Agent The coating agent for a dip-molded article of the present invention comprises the above-mentioned organic polymer fine particles and the above-mentioned polymer latex. The mixing ratio of the polymer latex and the organic polymer fine particles is 100 parts by weight of the polymer latex solid content,
The organic polymer fine particles usually have a solid content of 20 to 30.
The amount is 0 parts by weight, preferably 30 to 200 parts by weight, more preferably 50 to 150 parts by weight. When the compounding ratio is within this range, the balance of blocking resistance, desorption property and powder falling resistance is excellent.

The dip molded article coating agent is produced by mixing polymer latex and organic polymer fine particles. The method of mixing is not particularly limited, but the organic polymer fine particles obtained by previously separating and drying the polymer latex may be dispersed, or the aqueous dispersion of the polymer latex and the organic polymer fine particles obtained by the polymerization. You may mix and. Among them, the method of mixing the polymer latex and the aqueous dispersion of the organic polymer fine particles obtained by the polymerization is preferable from the viewpoint of more excellent powder falling resistance.

If desired, the dip-molded article coating agent may contain a thickening agent, a wetting agent, a defoaming agent, a pH adjusting agent, an antiaging agent and the like. Further, a water-affinity solvent such as alcohols, cellosolves, glycols, and glycerin may be appropriately blended depending on the purpose of improving the drying property and the film forming property.

The solid content concentration of the coating agent for a dip molded product is usually 1 to 15% by weight, preferably 3 to 12% by weight, more preferably 5 to 10% by weight.

Dip-molded product The dip-molded product of the present invention comprises a dip-molded product coated with the coating agent. The coating amount is not particularly limited, but is a solid content per unit surface area, preferably 0.1 to ² g / m ² , and more preferably 0.15 to 5 g / m ² .
It is 1.5 g / m ² .

The dip-molded article is not particularly limited, but gloves, finger sack obtained by dip-molding on a molding die by a conventional dip-molding method such as a direct dipping method, a coagulation dipping method, or a heat-sensitive dipping method. And so on. The dip-molded product is not particularly limited, but a product made of natural rubber latex or synthetic rubber latex can be used. Examples of the synthetic rubber latex include styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, carboxy-modified acrylonitrile-butadiene copolymer latex, and the like.
Among these, the coating agent of the present invention, in particular,
It can be suitably used for a glove obtained by a coagulation dipping method using a carboxy-modified acrylonitrile-butadiene copolymer latex.

The molding die used in the dip molding is, for example, porcelain, earthenware, metal, glass,
And those made of plastic. When the dip molded product is a glove, the mold has a shape corresponding to the contour of a human hand, and a shape from the wrist to the fingertip, depending on the intended use of the glove to be manufactured,
Various shapes such as a shape from the elbow to the fingertip can be used.

Examples of the method for coating the dip-molded product with the coating agent include a method of immersing the dip-molded product in the coating agent and a method of applying the coating agent to the dip-molded product. Among them, the method of immersing the dip-molded product in the coating agent is preferable because a uniform surface treatment layer can be easily obtained.

The coating may be performed subsequent to the dip molding in the manufacturing process of the dip molded product, or
The completed dip-molded product may be processed later. In either case, after coating, it is dried to obtain a dip-molded article. Further, the coating may be performed on only one side of the dip-molded article, on both sides thereof, or on the entire surface or a part thereof.

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

[0078]

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

(Evaluation of Polymer Latex and Organic Polymer Fine Particles) (1) Volume Average Particle Diameter (μm) Coulter LS230 (Coulter Particle Size Measuring Instrument)
It was measured at. (2) Glass transition temperature (° C) In the case of polymer latex, the polymer latex is cast on a glass plate with a frame and left in a constant temperature and humidity chamber at a temperature of 20 ° C and a relative humidity of 65% for 48 hours to obtain a film. This was used as a sample. In the case of organic polymer particles, an aqueous dispersion of organic polymer particles is cast on a glass plate with a frame, left for 48 hours in a constant temperature and humidity chamber at a temperature of 20 ° C. and a relative humidity of 65%, and dried. And The glass transition temperature of the above sample was measured by a differential scanning calorimeter (manufactured by Seiko Denshi Kogyo KK: SSC520).
0) was used under the conditions of a starting temperature of -100 ° C and a heating rate of 5 ° C / min.

(3) Flow start temperature The organic polymer fine particles obtained by drying as described above were further vacuum dried at 60 ° C. for 4 hours, and then compression molded into a cylindrical body having a bottom area of 1 cm ² and a height of 1 cm. did. Using a Shimadzu flow tester CFT-500C (manufactured by Shimadzu Corporation), the test load was 10 while the temperature was raised at a temperature rising rate of 3 ° C / min.
A piston subjected to kgf is extruded through a die having a die diameter of 0.5 mm and a die length of 1 mm, and measured by a 1/2 method from a change curve of piston stroke with respect to temperature. The measurement temperature range was 35 to 300 ° C. Here, the 1/2 method measures the temperature corresponding to the average piston stroke value of the minimum piston stroke value immediately before the start of extrusion from the die and the piston stroke value after the end of extrusion on the curve of change in piston stroke with respect to temperature. Is the way.

(Physical properties of gloves) (4) Releasability from hand mold Before hand, the hand mold after vulcanization and before the gloves are peeled off is put on a load cell of a Tensilon tensile tester (UTM-250 type: manufactured by Toyo Baldwin Co.). Was hung so that it faces down. Then, the temperature of the palm portion of the hand mold is measured with a laser-type non-contact thermometer (THI440N: manufactured by TASCO),
When the temperature reached 70 ° C., the gloves were peeled off from the hand mold while being inverted. At this time, the maximum value of the stress measured by the load cell is defined as the mold release stress. This test was performed 5 times, and the average value of the three releasing stresses excluding the maximum value and the minimum value of the five releasing stresses was taken as the average releasing stress. The smaller the average mold release stress, the easier the mold release from the hand mold.

(5) Removability The degree of difficulty when putting on and taking off gloves while the inner surface was dry was evaluated according to the following criteria.

(6) Blocking resistance A glove having a surface-treated layer on the inner side was overlaid with a load of 9.8 KPa applied from the outside. Temperature 40
After leaving the gloves in a constant temperature and humidity oven at a temperature of 95% and a humidity of 95% for 24 hours, the gloves were taken out, and the ease of peeling when the overlapped portions were peeled off with both hands was evaluated according to the following criteria. Evaluation criteria Blocking resistance A: Can be peeled off without difficulty. Blocking resistance B: Peeling requires force. Blocking resistance C: Not peelable. (7) Peeling resistance According to ASTM D6124-97, the amount of released resin (m
g) was measured. The smaller this amount is, the more excellent the powder falling resistance is.

Production of Polymer Latex (Production Example 1) 90 ml of deionized water was placed in a pressure vessel equipped with a stirrer.
Parts, butyl acrylate 58 parts, methyl methacrylate 42
Parts, and polyvinyl alcohol (PVA-224E, manufactured by Kuraray Co., Ltd., average degree of polymerization 2400, degree of saponification 88 mol%)
5 parts was added and stirred to obtain a monomer emulsion. Separately
A pressure resistant reaction vessel equipped with a stirrer was charged with 57 parts of deionized water and 8 parts of ethanol, and the temperature was raised to 80 ° C.
Was maintained, an initiator solution prepared by dissolving 0.5 part of ammonium persulfate in 10 parts of deionized water was added. After 2 minutes, the addition of the monomer emulsion to the reaction vessel was started, and the addition was completed over 4 hours. After the addition was completed, stirring was continued for another 2 hours and then cooled to terminate the reaction. The polymerization conversion rate at this time was 98%. After removing the unreacted monomer, the latex was adjusted to obtain a polymer latex having a solid content concentration of 40%. The volume average particle size of the obtained polymer latex was 0.31 μm, and the glass transition temperature was 4 ° C.

Production of organic polymer fine particles (Production Example 2) An average degree of polymerization of 500 in 200 parts of deionized water,
2.3 parts of polyvinyl alcohol having a saponification degree of 88 mol% was dissolved, and further 94.7 parts of styrene, 5 parts of butyl acrylate, 0.3 part of divinylbenzene, 0.8 part of t-dodecyl mercaptan and benzoyl peroxide ( BP
After adding a solution obtained by mixing 5 parts of (O), a homogenizer treatment was performed to prepare a fine dispersion liquid. This was transferred to a reaction vessel equipped with a stirrer capable of controlling temperature, and after nitrogen substitution, the temperature was raised to 90 ° C. to initiate polymerization. After 6 hours, the reaction was terminated by cooling. The polymerization conversion rate at this time was 97%. After removing the unreacted monomer, an organic polymer fine particle aqueous dispersion A having a solid content concentration of 30% was obtained. The volume average particle diameter of the organic polymer fine particles, the glass transition temperature of the polymer and the flow initiation temperature were measured, and the results are shown in Table 1.

(Production Examples 3 to 8) Except that the monomer mixture and the amount of benzoyl peroxide shown in Table 1 were changed.
The same procedure as in Production Example 2 was carried out to obtain organic polymer fine particle aqueous dispersions B to G. However, the flow starting temperature of the organic polymer fine particles G exceeded the upper limit of the measurement temperature range.

(Example 1) 100 parts of polymer latex (as solid content) and organic polymer fine particle aqueous dispersion A100
Parts (in terms of solid content) were mixed, and the total solid content concentration was adjusted to 8% with deionized water to obtain a coating agent for a dip molded product.

Vulcanizing agent dispersion 7 having a solid content concentration of 50.2%, prepared by mixing 10 parts of sulfur, 15 parts of zinc oxide, 7 parts of titanium oxide, 0.3 part of potassium hydroxide and 32 parts of water.
Part was mixed with 333 parts of a carboxy-modified acrylonitrile-butadiene copolymer latex for dip molding having a solid content concentration of 30% to obtain a dip molding compound solution having a solid content concentration of 30.4%.

On the other hand, a coagulant solution having a solid content concentration of 20.4% prepared by mixing 20 parts of calcium nitrate, 0.05 part of polyoxyethylene octylphenyl ether as a nonionic emulsifier and 80 parts of deionized water. A glove made of porcelain was immersed in the above for 1 minute, pulled up, and then dried at 50 ° C. for 3 minutes to adhere the coagulant to the glove.

Next, the glove mold to which the coagulant was attached was dipped in the above dip molding compound solution for 10 seconds and pulled up to 6
It was dried at 0 ° C. for 5 minutes, immersed in warm water at 50 ° C. for 5 minutes, and further dried at 60 ° C. for 5 minutes.

Then, the glove type is applied to the coating agent 10 times.
After dipping for 2 seconds and pulling up, it was dried at 70 ° C. for 10 minutes with a drier, and further vulcanized at 120 ° C. for 25 minutes to obtain a solid coating on the surface of the glove mold. Finally, the solid coating was peeled off while being inverted from the mold to obtain a rubber glove having a coating layer inside. The thickness of this rubber glove was 0.15 mm, and the coating amount was 1 g / m ² . The properties of this glove were evaluated and the results are shown in Table 1.

(Examples 2 to 4) The same procedure as in Example 1 was carried out except that the organic polymer fine particle aqueous dispersions B to D were used in place of the organic polymer fine particle aqueous dispersion A. The results are shown in Table 1.

Comparative Examples 1 to 3 The same procedure as in Example 1 was carried out except that the organic polymer fine particle aqueous dispersions E to G were used in place of the organic polymer fine particle aqueous dispersion A. The results are shown in Table 1.

[0094]

[Table 1]

The following can be seen from Table 1. The coating agent of Comparative Example 1 using the organic polymer fine particle aqueous dispersion E having a low flow starting temperature of the polymer and having a difference between the glass transition temperature and the flow starting temperature smaller than the range specified in the present invention was coated. Although gloves have excellent removability and powder falling resistance, they are inferior in releasability from a hand mold and blocking resistance. The glove coated with the coating agent of Comparative Example 2 using the organic polymer fine particle aqueous dispersion F in which the difference between the glass transition temperature and the flow initiation temperature in the polymer was smaller than the range specified in the present invention was separated from the hand mold. Excellent in moldability and detachability, but inferior in blocking resistance and powder falling resistance.
A glove coated with the coating agent of Comparative Example 3 using the organic polymer fine particle aqueous dispersion G in which the glass transition temperature and the flow initiation temperature of the polymer are higher than the ranges specified in the present invention,
Although it is excellent in releasing from the hand mold, blocking resistance, and detachability, it is inferior in powder falling resistance.

In comparison with these, all the gloves coated with the coating agent within the range specified in the present invention,
It is easily released from the hand mold, and has excellent blocking resistance, detachability, and powder falling resistance (Examples 1 to 4).

[0097]

According to the present invention, it is easy to release from the hand mold,
Provided are a dip-molded article coating agent capable of producing a dip-molded article which has excellent blocking resistance, is easy to put on and take off, and is hard to fall off powder, and a dip-molded article coated with the coating agent.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 133/06 C09D 133/06 // B29K 21:00 B29K 21:00 B29L 31:48 B29L 31:48 F Terms (reference) 4F205 AA13K AA21K AA45 AB11 AB23 AC05 AH70 GA08 GB01 GF01 GF02 4J038 CA021 CA022 CC011 CC012 CC061 CC062 CC101 CC102 CG121 CG122 CG141 CG142 CG161 CG162 CG171 CG172 CH031 CH132 MA10 MA14 MA10 MA14 MA14

Claims (6)

[Claims] 1. A coating agent for a dip molded article, which comprises organic polymer fine particles and a polymer latex, wherein the polymer constituting the organic polymer fine particles has a glass transition temperature of 40 to 120 ° C. and a flow initiation temperature. Is 90-270
℃, and the flow start temperature is 20 from the glass transition temperature
A coating agent for a dip molded product, which is characterized by having a temperature of up to 200 ° C. 2. An organic polymer fine particle is a crosslinkable monomer of 0.1.
The coating agent for a dip molded article according to claim 1, which is obtained by suspension polymerization of a monomer mixture containing 7 to 7% by weight. 3. A monomer mixture comprising 50-98% by weight of styrene, 1.9-43% by weight of butyl acrylate, 0.1-7% by weight of a crosslinkable monomer and 0-10 of other monomers. The coating agent for a dip-molded article according to claim 2, wherein the coating agent is composed of wt%. 4. The monomer mixture is methyl methacrylate 5
The composition according to claim 2, which comprises 0 to 98% by weight, butyl acrylate 1.9 to 43% by weight, a crosslinkable monomer 0.1 to 7% by weight, and another monomer 0 to 10% by weight. Coating agent for dip molded products. 5. Organic polymer fine particles in a solid content of 20 to 300 per 100 parts by weight of a polymer latex solid content.
The coating agent for a dip-molded article according to claim 1, which is contained in an amount of 1 part by weight. 6. A dip-molded article coated with the coating agent according to claim 1.