JP2001011239A - Latex for dip-forming and dip-formed product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dip-formed product unlikely to cause protein allergy, having soft touch and furthermore excellent in mechanical strength, and to provide a latex for dip-forming therefor. SOLUTION: This latex for dip-forming is a copolymer latex obtained by polymerizing a monomer mixture comprising 10-90 wt.% of a conjugated diene monomer, 0.1-20 wt.% of an ethylenically unsaturated acid monomer and 10-89.9 wt.% of other ethylenically unsaturated monomers copolymerizable therewith, wherein the amount of acid groups bonded to or adsorbed on the surface of the copolymer latex constituting the latex and that of the acid groups in the aqueous phase of the copolymer latex add up to 0.1-2.0 milliequivalent, in terms to hydrochloric acid, per 1 gram of the copolymer. Another objective dip-formed product is obtained by dip-forming the latex.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dip-formed product and a dip-forming latex, and more particularly, to a dip-formed product having excellent oil resistance, high mechanical strength, and a soft and uniform film. The present invention relates to a latex for dip molding for obtaining a molded product.

[0002]

2. Description of the Related Art Conventionally, rubber gloves obtained by dip molding a composition obtained by blending a vulcanizing agent such as sulfur with natural rubber latex have been used. But recently,
There is a problem that natural proteins contained in natural rubber latex cause allergic reactions by contacting human skin, causing rashes, itchiness and the like. On the other hand, dip molding is also performed from a composition in which zinc oxide is blended as a vulcanizing agent with a carboxylic acid-modified nitrile copolymer latex such as an acrylic acid-acrylonitrile-butadiene copolymer latex. The dip molded product thus obtained is particularly excellent in oil resistance,
Due to its high mechanical strength, it has been awarded in workplaces using organic solvents. However, this type of molded article has a disadvantage that the texture is hard. Therefore, in order to soften the texture of the dip-formed product, a method in which natural rubber latex and a carboxylic acid-modified nitrile-based copolymer latex are alternately stacked to form a dip, or a carboxylic acid-modified nitrile-based copolymer latex and a carboxylic acid A method of dip-forming a mixed latex (Japanese Unexamined Patent Publication No. 53-101036) in which a modified synthetic cis-1,4-polyisoprene rubber latex is mixed has been proposed. However, the dip-molded articles obtained by these methods have the above-mentioned problem of protein allergy, and also have the problems that the steps are complicated and the productivity is low.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dip-formed article which is free from the possibility of causing protein allergy, has a soft texture, and is excellent in mechanical strength. To provide latex.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the amount of acid groups on the surface of the copolymer constituting the latex and the amount of acid groups in the aqueous phase of the copolymer latex are determined. It has been found that this object can be achieved by using a latex having a total amount within a specific range, and the present invention has been completed based on this finding.

Thus, according to the present invention, 10 to 90% by weight of a conjugated diene monomer and 0.1 to 0.1% of an ethylenically unsaturated acid monomer are used.
A latex of a copolymer obtained by polymerizing a monomer consisting of 10 to 89.9% by weight and 10 to 89.9% by weight of another ethylenically unsaturated monomer copolymerizable with these monomers. The sum of the amount of acid groups bonded or adsorbed on the surface of the copolymer constituting the latex and the amount of acid groups in the aqueous phase of the copolymer latex is 0.1% / g of copolymer in terms of hydrochloric acid equivalent.
A latex for dip molding is provided, which is 1 to 2.0 meq.

Further, according to the present invention, there is provided a dip-formed product obtained by dip-forming the above-mentioned dip-forming latex.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The latex for dip molding of the present invention comprises 10 to 90% by weight of a conjugated diene monomer and 0.1% of an ethylenically unsaturated acid monomer.
It is a latex of a copolymer obtained by polymerizing a monomer consisting of 10 to 89.9% by weight and 10 to 89.9% by weight of another ethylenically unsaturated monomer copolymerizable with these monomers.

The conjugated diene monomer that can be used in the present invention is not particularly limited, and specific examples thereof include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 2-ethyl. -1,3-butadiene, 1,3-
Examples thereof include pentadiene and chloroprene. One of these conjugated diene monomers may be used alone, or two or more thereof may be used in combination.
Of the above, 1,3-butadiene or isoprene is preferably used.

The amount of the conjugated diene monomer used is
It is 0 to 90% by weight, preferably 20 to 80% by weight, and more preferably 25 to 75% by weight. If the amount is less than 10% by weight, the texture as a glove cannot be obtained, and if it is more than 90% by weight, the shape retaining property as a glove cannot be obtained. The amount of the conjugated diene monomer may be appropriately determined within the above range according to the type of the other ethylenically unsaturated monomer copolymerizable therewith, which is used in combination therewith,
When an ethylenically unsaturated nitrile monomer is used as another ethylenically unsaturated monomer, 30 to 9
0% by weight, preferably 35 to 80% by weight. If the amount of the conjugated diene monomer is less than 30% by weight, the texture of the dip molded product becomes hard, and if it is more than 90% by weight, the oil resistance of the dip molded product deteriorates,
It is not preferable because the tensile strength and the tear strength decrease. When an aromatic vinyl monomer is used as another ethylenically unsaturated monomer, the amount is 10 to 90% by weight, preferably 20 to 80% by weight of the monomer. If the amount is less than 10% by weight, the feeling of the dip molded product becomes hard, and if it is more than 90% by weight, the tensile strength and the tear strength are undesirably reduced.

The ethylenically unsaturated acid monomer which can be used in the present invention is not particularly limited as long as it is an ethylenically unsaturated monomer containing an acidic group such as a carboxyl group, a sulfonic acid group and an acid anhydride group. Not done. Specific examples thereof include ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; ethylenically unsaturated polycarboxylic acid monomers such as itaconic acid, maleic acid, fumaric acid and butenetricarboxylic acid; Monoester monomers of ethylenically unsaturated polycarboxylic acids such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate; polycarboxylic anhydrides such as maleic anhydride and citraconic anhydride; styrene sulfone Acid, vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamide-2
-Ethylenically unsaturated sulfonic acid monomers such as hydroxypropanesulfonic acid; (meth) acrylic acid-3-chloro-
Ethylenically unsaturated phosphoric acid monomers such as 2-propyl phosphate, (meth) acrylic acid-2-ethyl phosphate, and 3-allyloxy-2-hydroxypropane phosphoric acid; and the like.

These ethylenically unsaturated acid monomers can be used as alkali metal salts or ammonium salts. One of these ethylenically unsaturated acid monomers may be used alone, or two or more thereof may be used in combination. Of the above, methacrylic acid is particularly preferably used. The amount of the ethylenically unsaturated acid monomer used is 0.1 to 20% by weight of the monomer, preferably 1 to 15% by weight, more preferably 2 to 10% by weight. When the amount is less than 0.1% by weight, the tensile strength of the dip-formed product is reduced. On the contrary, when the amount is more than 20% by weight, the tear strength of the dip-formed product is lowered and the hand becomes hard.

Other ethylenically unsaturated monomers copolymerizable with the conjugated diene monomer and the ethylenically unsaturated acid monomer include an ethylenically unsaturated nitrile monomer, an aromatic vinyl monomer, Ethylenically unsaturated acid derivative monomers, crosslinkable monomers and the like can be used. The type and amount of these monomers are appropriately determined in consideration of various characteristics such as texture, oil resistance, and mechanical strength required for a target dip molded product.

[0013] The ethylenically unsaturated nitrile monomer is not particularly limited. Specific examples thereof include acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, and α-cyanoethylacrylonitrile. Of these ethylenically unsaturated nitrile monomers, acrylonitrile is preferred.
The amount of the ethylenically unsaturated nitrile monomer to be used may be determined according to the required characteristics of the desired dip molded product, but is usually 9 to 50% by weight of the monomer, preferably 20 to 50% by weight.
45% by weight. If the amount is less than 9% by weight, the oil resistance of the dip molded product will be poor, and if it is more than 50% by weight, the hand of the dip molded product will be hard.

[0014] The aromatic vinyl monomer is not particularly limited. Specific examples include styrene, methylstyrene,
Examples thereof include vinyl toluene, chlorostyrene, and hydroxymethylstyrene. Of these aromatic vinyl monomers, styrene is preferred. The amount of the aromatic vinyl monomer to be used may be determined according to the required characteristics of the target glove, but is usually 10 to 89.9% by weight, preferably 20 to 80% by weight of the monomer. . If the amount is less than 10% by weight, the texture of the dip molded product becomes too soft, and if it is more than 89.9% by weight, the texture of the dip molded product becomes hard.

The ethylenically unsaturated acid derivative monomer is not particularly limited. Specific examples thereof include, for example, ethylenically unsaturated acid ester monomers and ethylenically unsaturated acid amide monomers.

The ethylenically unsaturated acid ester monomer comprises an ethylenically monounsaturated acid or an ethylenically polyunsaturated acid,
It is an ester with various alcohols which may have a substituent such as halogen. Specific examples of the ethylenically unsaturated 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, 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,
(Meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, and N, N-dimethylaminoethyl (meth) acrylate; dibutyl maleate and fumarate Polycarboxylic acid esters such as dibutyl acid and diethyl maleate; and the like.

Specific examples of the ethylenically unsaturated acid amide monomer include, for example, (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth)
(Meth) acrylamide-based monomers such as acrylamide and N-propoxymethyl (meth) acrylamide.

Examples of the crosslinkable monomer include conjugated divinyl compounds such as divinylbenzene; polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol (meth) A) acrylate and other poly (meth) acrylate compounds.

The latex for dip molding of the present invention comprises the amount of acid groups bonded or adsorbed on the surface of the copolymer constituting the latex (hereinafter referred to as "surface acid group amount") and the aqueous phase of the copolymer latex. The total acid group content (hereinafter, referred to as "aqueous phase acid group amount") (hereinafter, sometimes referred to as "total acid group amount") in terms of hydrochloric acid equivalent is 0.1 g / g of the copolymer. 1 to
The amount is preferably 2.0 meq, more preferably 0.15 to 1.8 meq per gram of the copolymer. If the total acid group content is less than 0.1 milliequivalent, crosslinking in gloves becomes insufficient and the tear strength becomes weak, and the colloid stability of the latex becomes insufficient. Occasionally, a solidified product may be generated. 2.
If it exceeds 0 meq, there is a problem that the hydrophilic component of the glove becomes excessive and the strength at the time of immersion in water is reduced.

The method for controlling the total amount of the acid groups within the above range is not particularly limited, but usually, the type and amount of the ethylenically unsaturated acid monomer used in the polymerization or the method for controlling the polymerization reaction system are mainly This is performed by adjusting the timing of addition. In addition, the type or amount of the emulsifier or the polymerization initiator;
It is possible to use a method of adjusting H or the like together.

The latex for dip molding of the present invention is usually produced by an emulsion polymerization method. The polymerization temperature at the time of emulsion polymerization is not limited. However, it is preferable to carry out the polymerization at 45 ° C. or lower because a dip molded product having a high mechanical strength and a soft texture can be obtained.

In the production of the dip molding latex of the present invention, the method of adding the monomer mixture is not particularly limited.
A method in which the monomer mixture is charged to the polymerization reactor all at once, a method in which the monomer mixture is continuously supplied to the polymerization reactor, a part of the monomer mixture is charged in the polymerization reactor, and the remaining monomer is charged. Any method such as a method of continuously supplying the polymer to the polymerization reactor may be employed.

The polymerization initiator used for producing the dip-forming latex of the present invention is not particularly limited.

Specific examples include sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate,
Inorganic peroxides such as hydrogen peroxide; diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1,3,3
3-tetramethylbutyl hydroperoxide, 2,
Organic peroxides such as 5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, di-α-cumyl peroxide, acetyl peroxide, isobutyryl peroxide, benzoyl peroxide; azo Bisisobutyronitrile, azobis-
Examples include azo compounds such as 2,4-dimethylvaleronitrile and methyl azobisisobutyrate. These polymerization initiators can be used alone or in combination of two or more. The peroxide initiator is preferably used because a latex can be stably produced, and a dip molded product having a high mechanical strength and a soft texture can be obtained. The amount of the initiator used varies slightly depending on the type of the initiator, but is preferably 0.01 to 0.6% by weight based on the monomer mixture.

Further, a combination of a peroxide initiator and a reducing agent is used as a redox polymerization initiator.

The reducing agent of the redox polymerization initiator is not particularly limited, and specific examples thereof include compounds containing metal ions in a reduced state such as ferrous sulfate and cuprous naphthenate; sodium methanesulfonate And the like; amine compounds such as dimethylaniline; and the like. These reducing agents can be used alone or in combination of two or more. The amount of the reducing agent varies slightly depending on the reducing agent, but is preferably 0.03 to 1 part by weight of the peroxide.
It is preferably 10 parts by weight.

Among these initiators, a redox polymerization initiator obtained by combining a peroxide initiator and a reducing agent is preferred.

The emulsifier used in the dip-forming latex of the present invention is not particularly limited, either. For example, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, and polyoxyethylene sorbitan alkyl ester. Emulsifier; myristic acid, palmitic acid,
Oleic acid, fatty acids such as linolenic acid and salts thereof, higher alcohol sulfates, alkyl sulfosuccinic acids, alkylbenzene sulfonates, anionic emulsifiers such as aliphatic sulfonates; ammonium chlorides such as trimethylammonium chloride and dialkylammonium chloride; Benzylammonium salt and the fourth
Cationic emulsifiers such as quaternary ammonium salts; and copolymerizable emulsifiers such as sulfoesters of α, β-unsaturated carboxylic acids, sulfate esters of α, β-unsaturated carboxylic acids, and sulfoalkylaryl ethers. In particular, an anionic emulsifier or a nonionic emulsifier is preferably used. These emulsifiers can be used alone or in combination of two or more. The amount of the emulsifier used is not particularly limited, but may be 0.1 to 9 based on the monomer mixture.
It is preferably 0% by weight.

In the polymerization of the latex for dip molding of the present invention, if necessary, a polymerization auxiliary material such as a molecular weight modifier, a particle diameter modifier, an antioxidant, a chelating agent, an oxygen scavenger and the like may be used. it can.

When it is necessary to improve the mechanical strength of a dip-formed product with the latex of the present invention, it is preferable to add a metal oxide such as zinc oxide as a compound thereof. It is generally known to crosslink polymers with a vulcanizing agent such as sulfur in order to impart a rubber latex film strength. Latexes having an acidic group such as carboxylic acid on the particle surface are said to undergo metal cross-linking between polymers via metal ions by adding a metal oxide such as zinc oxide. It is generally known that a strength comparable to that of the above can be obtained.
By utilizing this reaction, it is possible to obtain more optimal strength as compared with the film strength development by sulfur vulcanization. However, it has been pointed out that the use of this metal crosslinking alone hardens the texture, and it is preferable to control the total amount of acid groups in the latex or use it together with sulfur vulcanization.

Examples of metal oxides other than zinc oxide include magnesium oxide and lead oxide. The amount used is usually 0.1 to 5 parts by weight per 100 parts by weight of latex.
% By weight, preferably 0.5% to 3% by weight.
If it is less than 0.1% by weight, the strength is small, and if it is more than 5% by weight, the effect of addition on the strength and the like is saturated, and it is not economical.

The dip-formed product of the present invention is obtained by dip-forming the dip-forming latex of the present invention. In general, dip molding is performed by immersing a mold in a dip molding compound liquid, depositing latex on the surface of the mold, and then pulling up the latex-deposited mold from the dip molding compound liquid.
It is performed by drying. Specific examples of the dip forming method include a direct immersion method, an anodic adhesion immersion method, and a teag adhesion immersion method.

The composition for dip molding used for dip molding is a composition containing the latex for dip molding of the present invention as a main component. In general, the dip-forming compounding liquid contains, in addition to the dip-forming latex, a vulcanizing agent (crosslinking agent), a vulcanization aid for cross-linking the latex with metal ions, a vulcanization accelerator, and a base as a pH adjuster. Is blended.
If necessary, an antioxidant, a filler, a thickener and the like can be added. The latex for dip molding of the present invention used in the dip molding compounding liquid can be used alone or in combination of two or more. Further, other latexes such as natural rubber latex and isoprene rubber latex can be used in combination, as long as the object of the present invention is not impaired.

In dip molding, a coagulant is used before the mold is immersed in the compounding liquid or after the mold is pulled up from the compounding liquid. Examples of the method of use include a method in which the mold before immersion is immersed in a solution of the coagulant to adhere to the mold, and a method in which the solution of the coagulant is sprinkled on the mold in which latex is deposited.

In dip molding, hot water treatment or heat treatment is carried out after withdrawing from the dip molding composition. By performing the warm water treatment or the heat treatment, the surplus monomers and the compounding aid are removed, and the crosslinking reaction of the copolymer is promoted. The method of hot water treatment or heat treatment is not particularly limited,
For example, a method of immersing a latex-deposited mold in warm water, a method of blowing hot air in an oven or the like on the latex-deposited mold, and a method of irradiating the latex-deposited mold with infrared rays are exemplified. it can.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Parts and% in Examples and Comparative Examples are based on weight unless otherwise specified. Further, the weight of the latex is expressed in terms of solid content unless otherwise specified. In addition, various measured values in the examples were obtained by the following methods.

(Amount of acid groups per 1 g of copolymer latex)
A glass container washed with distilled water and having a capacity of 150 ml was charged with 50 g of the copolymer latex whose solid content was adjusted to 2%, and a solution conductivity meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd .: CM-11)
7. Set in the cell type used: K-121) and stir. Thereafter, stirring is continued until the addition of hydrochloric acid is completed.
The electric conductivity of the copolymer latex is 2.5 to 3.0 (m
After adding 0.1 N sodium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd .: reagent grade) to the copolymer latex so as to become S), the electric conductivity is measured after 6 minutes have passed. This value is defined as the electrical conductivity at the start of the measurement. To this copolymer latex, 0.5 ml of 0.1 N hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd .: reagent grade) is added, and after 30 seconds, the electric conductivity is measured.
0.5 ml of 0.1N hydrochloric acid is added again, and 30 seconds later, the electric conductivity is measured. This operation is repeated at intervals of 30 seconds until the electric conductivity of the copolymer latex becomes equal to or higher than the electric conductivity at the start of the measurement.

The obtained electric conductivity data was plotted on a graph in which the vertical axis: electric conductivity (mS) and the horizontal axis: cumulative amount of added hydrochloric acid (mmol), as shown in FIG.
An amount of hydrochloric acid-electric conductivity curve having two inflection points is obtained. Three inflection point X coordinate and X-coordinate at the hydrochloric completion of the addition of, and in turn each _{P 1,} P 2, _{P 3} and _{P 4} from the smaller value, X coordinate from zero to _{P 1,} from _{P 1} to P _2, from _{P 2} from to _{P 3} and _{P 3} to _{P 4,} the four data in the section of each by the least squares method obtaining an approximate straight line _{L 1,} L 2, _{L 3} and _{L 4.} L ₁ and L
The X coordinate of the intersection of the _{2 A 1} (mmol), _{L 2} and _{L 3} X coordinate of the intersection between the _{A 2} (mmol), the X coordinate of the intersection between _{L 3} and _{L 4 A 3} and (mmol) I do.

The amount of surface acid groups per 1 g of the copolymer and the amount of aqueous acid groups per 1 g of the copolymer are given as milliequivalents in terms of hydrochloric acid from formulas (a) and (b), respectively. Therefore, the amount of acid group per 1 g of the copolymer latex is the sum of those formulas (a) and (b) as shown in formula (c). (A) Amount of acid groups on the surface per 1 g of polymer = A ₂ -A ₁ (b) Amount of acid groups in the aqueous phase per 1 g of polymer = A ₃ -A ₂ (c) Per 1 g of copolymer latex Total acid group content =
(A) + (b)

(Hand) A test piece was prepared by punching a dip-formed product with a dumbbell deformation No. 2 (small), and a tensile speed of 5
It was pulled at 00 mm / min, and the tensile strength when the elongation was 300% was measured. The smaller the value, the softer the texture.

(Tensile Strength) A test piece was prepared by punching out a dip-formed product with a dumbbell deformation No. 2 (small size), pulled at a tensile speed of 500 mm / min, and the tensile strength immediately before breaking was measured.

(Strength after immersion in water) A test piece prepared by punching a dip molded product with a dumbbell deformation No. 2 (small) was immersed in water for 3 hours, and after wiping off excess water, a tensile speed of 50% was applied.
It was pulled at 0 mm / min, and the tensile strength immediately before breaking was measured.

Example 1 In a polymerization reactor purged with nitrogen,
Acrylonitrile 34 parts, 1,3-butadiene 59 parts,
7 parts of methacrylic acid, 0.5 part of molecular weight modifier (TDM: t-dodecyl mercaptan), 150 parts of soft water, emulsifier (sodium dodecylbenzenesulfonate: LAS-Na)
2.5 parts, 0.2 parts of an initiator (potassium persulfate) and 0.1 part of a reducing agent (ethylenediaminetetraacetic acid) were charged, and the polymerization was maintained at 30 ° C. and reacted for 20 hours. Was added to terminate the polymerization. After removing unreacted monomers from the obtained latex, p of copolymer latex
H and the concentration were adjusted to obtain a solid concentration of 45% and a pH of 8.3.
Was obtained. Table 1 shows the physical properties of the obtained latex.

[0044]

[Table 1]

(Examples 2 to 4, Comparative Examples 1 to 3) A solid content of 45% was obtained in the same manner as in Example 1 except that the monomer composition was changed.
%, PH 8.3 copolymer latex was obtained. Table 1 shows the physical properties of the obtained latex.

Example 5 1.0 part of sulfur and 1.
0 parts, titanium oxide 1.0 parts and potassium hydroxide 0.03
Of the vulcanizing agent solution having a solid content of 50% prepared by mixing 3.2 parts of water and 3.2 parts of water with the solid content of 45% obtained in Example 1.
% Of latex to obtain a dip molding compounding liquid. On the other hand, calcium nitrate 20 parts, nonionic emulsifier (Emulgen-810: product of Kao Corporation) 0.05
The glove mold was immersed in a coagulant solution having a solid content concentration of 20% prepared by mixing the mixture and 80 parts of water for 1 minute, pulled up, dried at 50 ° C. for 3 minutes, and allowed to adhere to the glove mold. Next, the glove mold to which the coagulant was adhered was immersed in the compounding solution for dip molding for 6 minutes, pulled up, and dried at 20 ° C. for 3 minutes. Next, the glove mold was dried in a dryer at 80 ° C. for 20 minutes, subsequently heated to 120 ° C., and heat-treated for 25 minutes to obtain a solid film on the surface of the glove mold. Finally, the solid film was peeled from the glove mold to obtain a glove-shaped dip-formed product. Table 1 shows the evaluation results of these dip-formed products.

(Examples 6 to 8, Comparative Examples 4 to 6) Example 2
To 4, and the same evaluation as in Example 5 was performed using the copolymer latexes obtained in Comparative Examples 1 to 3. Table 1 shows the results.

From the evaluation results of the dip molded products in Table 1, the following can be understood for the dip molded products of the comparative examples. The dip-formed product of Comparative Example 6 obtained using the latex of Comparative Example 1 having a total acid group content smaller than the range specified in the present invention has a soft feel, but also a low tensile strength and a low strength after immersion in water. The dip-formed product of Comparative Example 5 obtained by using the latex of Comparative Example 2 having a total acid group content larger than the range specified in the present invention has a high tensile strength, a hard feel, and a low strength after immersion in water. . Comparative Example 6 obtained using the latex of Comparative Example 3 having a total acid group content larger than the range specified in the present invention.
Although the dip-formed product has a high tensile strength, it has a hard feel and a low strength after immersion in water.

On the other hand, it can be seen that the dip-formed products of Examples 5 to 8 using the copolymer latex of the present invention have a soft feel, and have high tensile strength and strength after immersion in water.

[0050]

Thus, according to the present invention, there can be obtained a dip molded product which has no fear of causing protein allergy, has a soft texture, and is excellent in mechanical strength, and a dip molding latex therefor.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a change in electric conductivity with respect to an added amount of hydrochloric acid.

[Explanation of symbols]

P ₁ The amount of hydrochloric acid at the first inflection point P ₂ The amount of hydrochloric acid at the second inflection point P ₃ The amount of hydrochloric acid at the third inflection point P _{4 The} amount of hydrochloric acid at the end of addition

Claims (2)

[Claims] 1. A conjugated diene monomer in an amount of 10 to 90% by weight, an ethylenically unsaturated acid monomer in an amount of 0.1 to 20% by weight, and other ethylenically unsaturated monomers copolymerizable with these monomers. A latex of a copolymer obtained by polymerizing a monomer consisting of 10 to 89.9% by weight of a copolymer, the amount of acid groups bonded or adsorbed on the surface of the copolymer constituting the latex and the copolymer A latex for dip molding, wherein the total of the amount of acid groups in the aqueous phase of the latex and the equivalent of hydrochloric acid is 0.1 to 2.0 meq / g of copolymer in terms of hydrochloric acid equivalent. 2. A dip molded product obtained by dip molding the latex for dip molding according to claim 1.