JP2015105281A - Composition for dip molding, and dip molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for dip molding capable of imparting a dip molded object excellent in water repellency and having a swelling rate suppressed lowly, and to provide a dip molded object obtained by using the composition for dip molding.SOLUTION: A composition for dip molding contains a latex of carboxyl group-containing nitrile rubber (A), a crosslinking agent, and a fatty acid soap and/or a resin acid soap (C). A dip molded object obtained by using the same is also provided.

Description

  The present invention relates to a dip-molding composition and a dip-molded article, and more specifically, a dip-molding composition that provides a dip-molded article having excellent water repellency and a low swelling rate, and the dip-molding article The present invention relates to a dip-molded article obtained using the composition.

  Conventionally, dip-molded products are known which are dip-molded with a dip-molding composition containing natural latex typified by natural rubber latex and used in contact with the human body such as nipples, balloons, gloves, balloons and sacks. It has been. However, since natural latex contains a protein that causes allergic symptoms in the human body, there are cases where there is a problem as a dip-molded product that comes into direct contact with living mucous membranes or organs. Therefore, studies have been made on using synthetic nitrile rubber latex.

  For example, Patent Document 1 includes 65 to 84.5 parts by weight of a conjugated diene monomer, 15 to 25 parts by weight of an ethylenically unsaturated nitrile monomer, and 0.5 to 10 parts by weight of an ethylenically unsaturated acid monomer. And a latex for dip molding obtained by copolymerizing 100 parts by weight of a monomer mixture composed of 0 to 19.5 parts by weight of other ethylenically unsaturated monomers copolymerizable therewith, and using the latex A dip-molded product obtained in this way is disclosed. The dip-molded article disclosed in Patent Document 1 has excellent texture and sufficient tensile strength, but has a low water repellency and a relatively high swelling rate. It has been necessary to perform a water repellent treatment by coating the surface of the surface using silicon or a fluorine-based polymer. In particular, gloves are frequently used even in working environments where water is used, so if they are used for gloves without water-repellent treatment, the grip properties may decrease or swell due to contact with water. This will cause problems.

JP 2003-165814 A

  An object of the present invention is to provide a dip-molding composition that provides a dip-molded article having excellent water repellency and a low swelling rate, and a dip-molded article obtained using the dip-molding composition And In particular, the present invention relates to a dip-molded product that can achieve excellent water repellency and low swelling without performing water-repellent treatment such as surface coating, and dip-molding suitable for manufacturing the dip-molded product. It is an object to provide a composition for use.

  As a result of diligent research to solve the above problems, the present inventors have found that the dip molding composition containing a carboxyl group-containing nitrile rubber latex, a crosslinking agent, and a fatty acid soap and / or a resin acid soap The inventors have found that the object can be achieved and have completed the present invention.

That is, according to the present invention, there is provided a dip molding composition containing a latex of a carboxyl group-containing nitrile rubber (A), a crosslinking agent (B), and a fatty acid soap and / or a resin acid soap (C). .
Preferably, the fatty acid soap and / or resin acid soap (C) is oleate and / or rosinate.

Moreover, according to this invention, the dip molding product obtained by carrying out the dip molding of the said composition for dip molding is provided. The dip-molded product is preferably obtained by dip molding using a polyvalent metal salt as a coagulant.
And it is preferable that the dip molded product of this invention is a glove.

  According to the present invention, there are provided a dip-molding composition that provides a dip-molded article having excellent water repellency and a low swelling rate, and a dip-molded article obtained by using the dip-molding composition. Can do. In particular, the dip-molded product obtained by using the dip-molding composition of the present invention can achieve excellent water repellency and low swelling ratio without performing water-repellent treatment such as surface coating. The water repellent treatment such as the above can be omitted, and thereby productivity can be improved.

FIG. 1 is a diagram showing a wet state of a dip-formed product in Examples and Comparative Examples of the present invention.

  The dip molding composition of the present invention is a dip molding composition containing a latex of a carboxyl group-containing nitrile rubber (A), a crosslinking agent (B) and a fatty acid soap and / or a resin acid soap (C).

Latex of carboxyl group-containing nitrile rubber (A) Latex of carboxyl group-containing nitrile rubber (A) used in the present invention is a conjugated diene monomer, ethylenically unsaturated nitrile monomer, ethylenically unsaturated carboxylic acid monomer And a latex of nitrile rubber obtained by copolymerizing other ethylenically unsaturated monomers copolymerizable therewith, and used as necessary.

  Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and chloroprene. It is done. Among these, 1,3-butadiene and isoprene are preferable, and 1,3-butadiene is more preferable. These conjugated diene monomers can be used alone or in combination of two or more. The amount of the conjugated diene monomer used is preferably 30 to 89 parts by weight, more preferably 40 to 84 parts by weight, and still more preferably 50 to 78 parts by weight with respect to 100 parts by weight of the total monomers used for the polymerization. is there. If the amount of the conjugated diene monomer used is too small, the resulting dip-molded product tends to be inferior in texture, and conversely if too large, the tensile strength tends to be inferior.

  Examples of the ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile and the like. Of these, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable. These ethylenically unsaturated nitrile monomers can be used alone or in combination of two or more. The amount of the ethylenically unsaturated nitrile monomer used is preferably 10 to 50 parts by weight, more preferably 15 to 45 parts by weight, still more preferably 20 to 40 parts by weight based on 100 parts by weight of the total monomers used for the polymerization. Parts by weight. If the amount of the ethylenically unsaturated nitrile monomer used is too small, the resulting dip-formed product tends to be inferior in tensile strength, and conversely if too large, the texture tends to be inferior.

  Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; ethylenically unsaturated polyvalent carboxylic acids such as itaconic acid, maleic acid and fumaric acid Monomers; ethylenically unsaturated polyvalent carboxylic acid partial ester monomers such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate; and other ethylenic monomers such as maleic anhydride and citraconic anhydride A monomer that generates a carboxyl group by hydrolysis of an unsaturated polycarboxylic acid anhydride, and the like. Among these, an ethylenically unsaturated monocarboxylic acid monomer is preferable, acrylic acid and methacrylic acid are more preferable, and methacrylic acid is particularly preferable. These ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. The amount of the ethylenically unsaturated carboxylic acid monomer used is preferably from 1 to 20 parts by weight, more preferably from 1 to 15 parts by weight, and even more preferably from 2 to 100 parts by weight based on 100 parts by weight of the total monomers used for the polymerization. 10 parts by weight. If the amount of the ethylenically unsaturated carboxylic acid monomer used is too small, the resulting dip-formed product tends to be inferior in tensile strength, and conversely if too large, the texture tends to be inferior.

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

  The amount of other ethylenically unsaturated monomers that can be copolymerized is 20 parts by weight or less, preferably 15 parts by weight or less, more preferably 10 parts by weight or less, based on 100 parts by weight of all monomers used for polymerization. It is. If the amount of other copolymerizable ethylenically unsaturated monomers used is too large, the resulting dip-molded product tends to be inferior in texture.

  The latex of the carboxyl group-containing nitrile rubber (A) used in the present invention is obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, and a method of copolymerization by emulsion polymerization is preferred. A conventionally well-known method can be employ | adopted as an emulsion polymerization method.

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

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

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

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

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

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

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

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

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

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

  After stopping the polymerization reaction, if desired, the unreacted monomer is removed, and the solid content concentration and pH are adjusted, whereby the carboxyl group-containing nitrile rubber (A) latex can be obtained.

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

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

Cross-linking agent (B)
As the crosslinking agent (B), those usually used in dip molding can be used, for example, sulfur such as powdered sulfur, sulfur white, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, etc .; hexamethylenediamine, triethylenetetramine And polyamines such as tetraethylenepentamine; and the like. Among these, sulfur is preferable. The blending amount of the crosslinking agent (B) in the dip molding composition of the present invention is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the latex of the carboxyl group-containing nitrile rubber (A). More preferably, it is 0.5 to 5 parts by weight.

Fatty acid soap and / or resin acid soap (C)
The fatty acid soap and / or resin acid soap (C) used in the present invention is a fatty acid salt and / or resin acid salt, and a fatty acid salt and / or resin acid salt obtained by neutralizing a fatty acid and / or resin acid with a base. Is preferred. In the present invention, in addition to the latex of carboxyl group-containing nitrile rubber (A) and the crosslinking agent (B), a dip-molded product obtained by blending fatty acid soap and / or resin acid soap (C) is obtained. Even when water repellent treatment such as surface coating is not performed, water repellency is excellent and the swelling rate can be kept low.

  Although it does not specifically limit as a fatty acid, A C5-C30 fatty acid is preferable and a C10-C20 fatty acid is more preferable. Specific examples of fatty acids include linear fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, and behenic acid; And the like. The resin acid is not particularly limited, and examples thereof include rosin acid (containing abietic acid, neoabietic acid, parastrinsic acid, pimaric acid, isopimaric acid, or dehydroabietic acid). These can be used alone or in combination of two or more. Among these, linear fatty acids and resin acids are preferable, oleic acid and rosin acid are more preferable, and oleic acid is particularly preferable from the viewpoint that the effect of improving water repellency and low swellability can be further enhanced. .

  The base is not particularly limited, but alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonia, methylamine, dimethylamine, ethylamine, diethylamine, (iso) propylamine, di ( Iso) propylamine, monoethanolamine, N-methylmonoethanolamine, N-ethylmonoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, 2-amino-2-methyl-1 -Propanol, 2-amino-2-methyl-1,3-propanediol, aminoethylethanolamine, N, N, N ', N'-tetrakis (hydroxyethyl) ethylenediamine, N, N, N', N'- Tetrakis (2-hydro Shipuropiru) amines such as ethylene diamine; and the like. These can be used alone or in combination of two or more. Among these, alkali metal hydroxides are preferable, sodium hydroxide and potassium hydroxide are more preferable, and potassium hydroxide is particularly preferable.

  That is, the fatty acid soap and / or resin acid soap (C) used in the present invention is preferably a linear fatty acid alkali metal salt and a resin acid alkali metal salt. More preferably, an alkali metal salt of a linear fatty acid and an alkali metal salt of a resin acid neutralized with a metal hydroxide, more preferably an alkali metal salt of a linear fatty acid, potassium oleate and oleic acid Sodium is particularly preferred.

  The blending amount of the fatty acid soap and / or the resin acid soap (C) in the dip molding composition of the present invention is preferably 0 with respect to 100 parts by weight of the solid content of the latex of the carboxyl group-containing nitrile rubber (A). 0.1 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, and particularly preferably 0.5 to 4 parts by weight. If the blending amount of fatty acid soap and / or resin acid soap (C) is too small, it may be difficult to obtain the effect of improving water repellency and low swellability. There is a risk of pinholes.

In addition to the above-mentioned latex of carboxyl group-containing nitrile rubber (A), crosslinking agent (B) and fatty acid soap and / or resin acid soap (C), other compounding agents and the like are also included in the dip molding composition of the present invention. If desired, a crosslinking aid, a crosslinking accelerator, a filler, a pH adjuster, a thickener, an anti-aging agent, a dispersant, a pigment, a filler, a softener and the like may be blended.

  As the crosslinking aid, those usually used in dip molding can be used, and examples thereof include zinc oxide, stearic acid, and a zinc salt of stearic acid. Among these, zinc oxide is preferable. These crosslinking aids can be used alone or in combination of two or more. The amount of the crosslinking aid is preferably 0.5 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the solid content of the latex of the carboxyl group-containing nitrile rubber (A).

  As the crosslinking accelerator, those usually used in dip molding can be used. Acids and their zinc salts; 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2- (2,4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthio-carbylthio) benzothiazole, 2- (2,6-dimethyl-4-morpholinothio) benzothiazole, 2- (4'-morpholino-dithio) benzothia Lumpur, 4-morpholinyl-2-benzothiazyl disulfide, 1,3-bis (2-benzothiazyl mercaptomethyl) such as urea and the like. Among these, zinc dibutyldithiocarbamate, 2-mercaptobenzothiazole, and zinc 2-mercaptobenzothiazole are preferable, and zinc dibutyldithiocarbamate is particularly preferable. These vulcanization accelerators can be used alone or in combination of two or more. The blending amount of the crosslinking accelerator is preferably 0.1 to 5 parts by weight, more preferably 0.2 to 2 parts by weight with respect to 100 parts by weight of the solid content of the latex of the carboxyl group-containing nitrile rubber (A). .

  The solid content concentration of the dip molding composition of the present invention is preferably 10 to 40% by weight, more preferably 15 to 35% by weight. Moreover, the pH of the dip molding composition of this invention becomes like this. Preferably it is 8.5-12, More preferably, it is 9-11.

Dip-molded product The dip-molded product of the present invention is obtained by dip-molding the above-described dip-molding composition of the present invention.
As the dip molding method, a normal method may be employed, and examples thereof include a direct dipping method, an anode adhesion dipping method, and a teag adhesion dipping method. Among these, the anode coagulation dipping method is preferable because a dip-molded product having a uniform thickness can be easily obtained.

  In the case of the anode adhesion dipping method, for example, a dip-molding mold is immersed in a coagulant solution, the coagulant is attached to the surface of the mold, and then the dip-molding composition is immersed in the dip-molding composition, A dip-formed layer is formed on the substrate.

  Although it does not specifically limit as a coagulant, In this invention, it is preferable to use a polyvalent metal salt. By using a polyvalent metal salt as a coagulant, the fatty acid and / or resin acid constituting the fatty acid soap and / or resin acid soap (C) contained in the dip molding composition of the present invention at the time of coagulation is a polyvalent metal. An ionic bond is formed with the polyvalent metal ion derived from the salt, whereby a polyvalent metal salt of a fatty acid or a polyvalent metal salt of a resin acid is formed. In the dip-molded product of the present invention, the water repellency and low swellability can be further improved by containing fatty acids and resin acids in the form of polyvalent metal salts of fatty acids and resin acids.

  Although it does not specifically limit as polyvalent metal salt, Polyvalent metal halides, such as barium chloride, calcium chloride, magnesium chloride, zinc chloride, and aluminum chloride; Polyvalent metal nitrates, such as barium nitrate, calcium nitrate, and zinc nitrate; Acetic acid And polyvalent metal acetates such as barium, calcium acetate and zinc acetate; and polyvalent metal sulfates such as calcium sulfate, magnesium sulfate and aluminum sulfate. Among these, since the effect of the present invention becomes more remarkable, a polyvalent metal salt in which the polyvalent metal is calcium is preferable, calcium chloride and calcium nitrate are more preferable, and calcium nitrate is particularly preferable.

  The coagulant is preferably used in the form of an aqueous solution. This aqueous solution may further contain a water-soluble organic solvent such as methanol or ethanol, or a nonionic surfactant. The coagulant concentration is usually 5 to 70% by weight, preferably 10 to 50% by weight.

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

  The crosslinking of the dip-molded layer is usually performed by performing a heat treatment at a temperature of 100 to 150 ° C., preferably 10 to 120 minutes. As a heating method, an external heating method using infrared rays or heated air or an internal heating method using high frequency can be employed. Of these, external heating with heated air is preferred.

  A dip-molded product is obtained by detaching the crosslinked dip-molded layer from the dip-molding die. As the desorption method, it is possible to adopt a method of peeling from the mold by hand, or peeling by water pressure or compressed air pressure. In addition, after desorption, you may heat-process for 10 to 120 minutes at the temperature of 60-120 degreeC.

  Further, the dip-molded product of the present invention is obtained using the above-described dip-molding composition of the present invention, and is excellent in water repellency and has a low swelling rate. It is suitable for applications that are used in contact with each other, specifically for glove applications, especially for thin surgical gloves. Alternatively, the dip-molded product of the present invention is not limited to gloves, but also medical supplies such as nipples for baby bottles, syringes, tubes, water pillows, balloon sacks, catheters and condoms; toys such as balloons, dolls and balls; It can also be used for industrial goods such as bags for gas and bags for gas storage;

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples. In the following, “part” is based on weight unless otherwise specified. The test and evaluation were as follows.

The contact angle (water contact angle) of the contact angle dip-formed product was measured using a trade name “FAMAS dropmaster 700” (manufactured by Kyowa Kagaku). An appropriate amount of the liquid at the time of measurement was 1.5 μL, and analysis was performed by the Young-Laplace method. It can be determined that the larger the contact angle, the better the water repellency.

Sprinkle 5 cc of water on the wet area dip-molded product using a spray bottle, leave it for 30 seconds, and then visually observe it in the range of 5 cm x 5 cm occupying most of the glove-shaped palm part. The ratio of the area wetted with water (unit:%) was determined. In addition, the measurement was performed 5 times and the average value was made into the wet area. It can be determined that the smaller the wet area, the better the water repellency.

The area swell ratio dip-molded product is punched into a circular shape using a 37 mmφ punching die to obtain a circular sample, and the obtained circular sample is immersed in distilled water at 24 ° C. in constant temperature and humidity for 2 hours. The area swelling rate was calculated according to the formula: It can be determined that the lower the area swelling rate, the better the low swelling property.
Area swelling rate (%) = {(sample area after immersion−sample area before immersion) / sample area before immersion} × 100

Production Example 1
Production of latex of carboxyl group-containing nitrile rubber (A-1) In a pressure-resistant polymerization reactor, 29 parts of acrylonitrile, 5.5 parts of methacrylic acid, 0.5 part of t-dodecyl mercaptan as a molecular weight regulator, 150 parts of deionized water, After charging 2.5 parts of sodium dodecylbenzenesulfonate and replacing the internal gas with nitrogen three times, 65.5 parts of 1,3-butadiene was charged. Next, 0.2 part of potassium persulfate and 0.1 part of sodium ethylenediaminetetraacetate were charged, and then the polymerization temperature was set to 39 ° C. to initiate the polymerization reaction. The polymerization reaction was continued until the polymerization conversion reached 97%, and then 0.1 part of diethylhydroxylamine was added to stop the polymerization reaction. After the unreacted monomer was distilled off under reduced pressure from the obtained copolymer latex, the solid content concentration and pH were adjusted, and the carboxyl group-containing nitrile rubber having a solid content concentration of 43% and a pH of 8.5 ( A latex of A-1) was obtained.

Example 1
Preparation of composition for dip molding Solid content in 232.5 parts of latex of carboxyl group-containing nitrile rubber (A-1) obtained in Production Example 1 (100 parts in terms of carboxyl group-containing nitrile rubber (A-1)) In terms of conversion, 1 part of sulfur (crosslinking agent (B)), 1 part of potassium oleate (fatty acid soap and / or resin acid soap (C)), 0.5 part of zinc dibutyldithiocarbamate (crosslinking accelerator), zinc oxide ( (Crosslinking aid) 1.5 parts, Titanium oxide (pigment) 1.5 parts, After adding the aqueous dispersion of each compounding agent, add aqueous potassium hydroxide to adjust the pH to 9.4. An adjusted dip molding composition (solid content concentration: 25% by weight) was obtained.

Production of dip-molded product A glass glove mold with a ground surface was washed and preheated in an oven at 70 ° C., and then 13 wt% calcium nitrate and 0.05 wt% polyoxyethylene lauryl ether ( It was immersed for 5 seconds in a 25 ° C. aqueous coagulant solution comprising “Emulgen 109P” (trade name, manufactured by Kao Corporation) and taken out.

  The glove mold coated with the coagulant was then dried in an oven at 70 ° C. Thereafter, the glove mold coated with the coagulant is taken out of the oven, dipped in the dip-forming composition obtained above (adjusted to 25 ° C.) for 10 seconds, taken out, and dried at room temperature for 60 minutes, A glove mold coated with a dip molding layer was obtained. The glass mold covered with this dip-molded layer was immersed in warm water at 60 ° C. for 2 minutes and then air-dried at room temperature for 30 minutes. Thereafter, the glass mold covered with the dip-molded layer was placed in an oven at 120 ° C. and crosslinked for 20 minutes. Next, the glass mold covered with the crosslinked dip-molded layer was cooled to room temperature, and the dip-molded layer was peeled from the glass mold. And the contact angle, the area swelling rate, and the wet area were measured about the obtained dip-molded product (gloves). The results are shown in Table 1.

Example 2
A dip-molding composition and a dip-molded article (gloves) in the same manner as in Example 1 except that the amount of potassium oleate as the fatty acid soap and / or resin acid soap (C) was changed from 1 part to 3 parts ) And evaluated in the same manner. The results are shown in Table 1.

Example 3
As a fatty acid soap and / or resin acid soap (C), in the same manner as in Example 1, except that 1 part of sodium rosinate was used instead of 1 part of potassium oleate, a composition for dip molding and a dip molded article were used. (Gloves) were obtained and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 1
A dip-molding composition and a dip-molded product (gloves) were obtained in the same manner as in Example 1 except that potassium oleate was not blended, and evaluation was performed in the same manner. The results are shown in Table 1.

Comparative Example 2
In the same manner as in Example 1, except that 1 part of sodium oleate was used instead of 1 part of potassium oleate as the fatty acid soap and / or resin acid soap (C), a dip molding composition and dip A molded product (gloves) was obtained and evaluated in the same manner. The results are shown in Table 1.

As shown in Table 1, obtained using a dip molding composition containing a latex of carboxyl group-containing nitrile rubber (A), a crosslinking agent (B), and fatty acid soap and / or resin acid soap (C). The dip-molded articles (gloves) of Examples 1 to 3 have a large contact angle, a small wetted area, excellent water repellency, a low area swelling rate, and a low swelling rate. In particular, the dip-molded articles (gloves) of Examples 1 to 3 were able to realize such characteristics without performing water-repellent treatment such as surface coating.
On the other hand, in Comparative Example 1 in which fatty acid soap and / or resin acid soap (C) was not blended, and in Comparative Example 2 in which sodium dodecylbenzenesulfonate was used instead of fatty acid soap and / or resin acid soap (C) The resulting dip-formed product (gloves) has a small contact angle, a large wetted area, poor water repellency, and a high area swelling rate (Comparative Examples 1 and 2). .
1 (A) shows the wet state at the time of measuring the wet area of the dip molded product (glove) obtained in Example 1, and FIG. 1 (B) shows the dip molded product obtained in Comparative Example 1 ( The wet state at the time of measuring the wet area of the gloves) is shown. Comparing FIG. 1 (A) and FIG. 1 (B) also confirms that the dip-formed product (gloves) obtained in Example 1 is excellent in water repellency. Here, only the wet state of Example 1 and Comparative Example 1 was shown, but Examples 2 and 3 also have the same tendency as Example 1, and Comparative Example 2 has the same tendency as Comparative Example 1. It was in.

Claims (5)

  A composition for dip molding containing a latex of a carboxyl group-containing nitrile rubber (A), a crosslinking agent (B), and a fatty acid soap and / or a resin acid soap (C).   The dip molding composition according to claim 1, wherein the fatty acid soap and / or the resin acid soap (C) is an oleate and / or a rosinate.   A dip-molded product obtained by dip-molding the dip-molding composition according to claim 1.   The dip-formed product according to claim 3, obtained by dip-molding using a polyvalent metal salt as a coagulant.   The dip-formed product according to claim 3 or 4, which is a glove.