KR101467020B1 - Carboxylic acid modified-nitrile based copolymer latex for dip-forming, latex composition for dip-forming comprising the same, and products thereof - Google Patents

Abstract

The present invention relates to a carboxylic acid-modified nitrile-based copolymer latex comprising two kinds of copolymers having different latex particle diameters, a latex composition for dip molding comprising the same, and a molded article produced therefrom, To 140 nm and a nitrile copolymer latex having an average particle diameter of 150 nm to 200 nm are blended and then used to manufacture a molded article having a high tensile strength and excellent wearing feeling.

Description

TECHNICAL FIELD The present invention relates to a carboxylic acid-modified nitrile-based copolymer latex for dip molding, a latex composition for dip molding comprising the same, and a molded article prepared from the latex composition, and products thereof}

The present invention relates to a carboxylic acid-modified nitrile-based copolymer latex for dip molding, a latex composition for dip molding comprising the same, and a molded article produced therefrom. More particularly, the present invention relates to a latex composition comprising two carboxylic acid modified nitrile- Copolymer latexes having a mean particle size of 100 nm to 140 nm and a carboxylic acid modified nitrile copolymer latex having an average particle size of 150 nm to 200 nm are manufactured and blended and used to obtain a high tensile strength The present invention relates to a carboxylic acid-modified nitrile-based copolymer latex capable of producing such an excellent molded article, a dip-shaped latex composition comprising the same, and a dip-formed article made therefrom.

Currently, efforts are being made by glove manufacturers to lighten nitrile rubber gloves. In order to reduce the weight of the glove, it is necessary to make the glove thin. However, when the glove is made thin, the tensile strength of the glove is lowered. Therefore, glove makers are interested in carbonic acid modified nitrile latex which does not deteriorate tensile strength even when making gloves thin, but carbonic acid denatured latex, which exhibits excellent tensile strength in lightweight gloves, is not yet available.

Accordingly, it is an object of the present invention to provide a carboxylic acid-modified nitrile-based copolymer latex which is capable of producing a molded article having a higher tensile strength and a better fit than conventional gloves.

Another object of the present invention is to provide a latex composition for deep molding comprising the carboxylic acid-modified nitrile-based copolymer latex and a molded article produced therefrom.

The above object of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a modified latex copolymer latex comprising two latexes having a different average particle size of latex and containing carboxylic acid modified nitrile copolymer latex, So that the conventional problems as described above can be solved.

According to the present invention, a carboxylic acid nitrile-based copolymer latex having an average particle size of latex of 100 nm to 140 nm and a carboxylic acid nitrile-based copolymer latex having an average particle size of 150 nm to 200 nm are blended and used, It is possible to manufacture molded products.

When a dipped molded article is produced by blending two latexes having different average particle diameters, more latex particles are formed within a unit area than a dip molded article produced from a latex having an average particle size of one, and a film having a high strength and a high flatness is formed The tensile strength is high and the wearing feeling is excellent.

The nitrile-based copolymer latex of the present invention comprises two modified nitrile-based copolymers having different latex average particle diameters. Preferably, a carboxylic acid-modified nitrile-based copolymer latex having an average particle diameter of 100 nm to 140 nm and a carboxylic acid-modified nitrile-based copolymer latex having an average particle diameter of 150 nm to 200 nm are prepared and then blended.

The weight ratio of the two carboxylic acid modified nitrile-based copolymer latexes having different average particle diameters is 10:90 to 90:10, and more preferably 20:80 to 80:20.

In order to achieve the other object of the present invention, a composition for dip molding comprising a carboxylic acid-modified nitrile-based copolymer latex is prepared by adding a vulcanizing agent, an ionic cross-linking agent, a pigment, a filler, And at least one additive selected from the group consisting of an antioxidant and a modifier.

Further, a dip molded article for achieving still another object of the present invention is characterized by being obtained by dip-molding the composition.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a process for preparing a carboxylic acid-modified nitrile-based copolymer latex by adding an emulsifier, a polymerization initiator and a molecular weight regulator to each monomer constituting the carboxylic acid-modified nitrile-based copolymer, The final product is formed by molding.

Hereinafter, the carboxylic acid-modified nitrile-based copolymer latex and the latex composition containing the latex used for obtaining the dip-shaped article of the present invention will be described in detail.

1. Carboxylic acid-modified nitrile-based copolymer latex

The carboxylic acid-modified nitrile-based copolymer latex according to the present invention is prepared by adding an emulsifier, a polymerization initiator, a molecular weight modifier, and other additives to each monomer constituting the carboxylic acid-modified nitrile-based copolymer, followed by emulsion polymerization.

The monomer constituting the carboxylic acid-modified nitrile-based copolymer is composed of 40 to 89% by weight of a conjugated diene monomer, 10 to 50% by weight of an ethylenically unsaturated nitrile monomer, and 0.1 to 10% by weight of an ethylenically unsaturated acid monomer.

Specific examples of the conjugated diene monomer as the other monomer constituting the carboxylic acid-modified nitrile-based copolymer according to the present invention include 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-butadiene, 1,3-pentadiene and isoprene. Of these, 1,3-butadiene and isoprene are preferable, and 1,3-butadiene is most preferably used.

The conjugated diene monomer is contained in an amount of 40 to 89% by weight, preferably 45 to 80% by weight, and most preferably 50 to 78% by weight in the total monomers constituting the carboxylic acid-modified nitrile-based copolymer. If the content of the conjugated dienic monomer is less than 40% by weight, the dip molded article becomes hard and the feeling of wearing becomes worse. When the content exceeds 89% by weight, the oil resistance of the dip molded article is deteriorated and the tensile strength is lowered.

As the other monomers constituting the carboxylic acid-modified nitrile-based copolymer according to the present invention, the ethylenically unsaturated nitrile-based monomer is at least one monomer selected from the group consisting of acrylonitrile, methacrylonitrile, fumaronitrile,? -Chloronitrile, Acrylonitrile, and acrylonitrile. Of these, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is most preferably used.

The ethylenically unsaturated nitrile monomer is contained in an amount of from 10 to 50% by weight, preferably from 15 to 45% by weight, and most preferably from 20 to 40% by weight, of the total monomers constituting the carboxylic acid-modified nitrile-based copolymer. When the content of the ethylenically unsaturated nitrile-based monomer is less than 10% by weight, the oil resistance of the dip-molded article deteriorates and the tensile strength decreases. When the ethylenically unsaturated nitrile-based monomer content exceeds 50% by weight, the dip-

As the other monomers constituting the carboxylic acid-modified nitrile-based copolymer according to the present invention, the ethylenically unsaturated acid monomer is an ethylenically unsaturated monomer containing at least one acidic group selected from the group consisting of a carboxyl group, a sulfonic acid group, and an acid anhydride group, Examples thereof include ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid; Polycarboxylic anhydrides such as maleic anhydride and citraconic anhydride; Ethylenically unsaturated sulfonic acid monomers such as styrenesulfonic acid; Ethylenic unsaturated polycarboxylic acid partial ester monomers such as monobutyl fumarate, monobutyl maleate, mono-2-hydroxypropyl maleate, and the like. Of these, methacrylic acid is particularly preferable. Such ethylenically unsaturated acid monomers can be used in the form of alkali metal salts or ammonium salts.

The ethylenic unsaturated acid monomer is contained in an amount of 0.1 to 10% by weight, preferably 0.5 to 9% by weight, more preferably 1 to 8% by weight, based on the total monomers constituting the carboxylic acid-modified nitrile-based copolymer. When the content of the ethylenically unsaturated acid monomer is less than 0.1% by weight, the tensile strength of the dip-molded article is lowered. When the content of the ethylenic unsaturated acid monomer is more than 10% by weight, the resulting dip-

The carboxylic acid-modified nitrile-based copolymer according to the present invention may further include other ethylenically unsaturated monomers copolymerizable with the ethylenically unsaturated nitrile monomer and the ethylenically unsaturated acid monomer, and specifically, styrene, alkylstyrene, A vinyl aromatic monomer selected from the group consisting of vinylnaphthalene and vinylnaphthalene; Fluoroalkyl vinyl ethers such as fluoro ethyl vinyl ether; (Meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl An ethylenically unsaturated amide monomer selected from the group consisting of: Nonconjugated diene monomers such as vinylpyridine, vinylnorbornene, dicyclopentadiene and 1,4-hexadiene; (Meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, trifluoroethyl (Meth) acrylate, dibutyl fumarate, diethyl maleate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, cyanomethyl Ethyl (meth) acrylate, 2-ethyl-6-cyanohexyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxy Ethylenically unsaturated carboxylic acid ester monomers selected from the group consisting of ethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, and dimethylaminoethyl It was used as the one or more kinds.

The amount of the ethylenically unsaturated nitrile monomer and other ethylenic unsaturated monomer copolymerizable with the ethylenic unsaturated acid monomer may be used in an amount of 20 wt% or less and 20 wt% or more of the total monomers constituting the carboxylic acid-modified nitrile-based copolymer The balance between soft fit and tensile strength does not fit well.

The carboxylic acid-modified nitrile-based copolymer latex of the present invention can be prepared by adding an emulsifier, a polymerization initiator, a molecular weight modifier, and the like to the monomers constituting the carboxylic acid-modified nitrile-based copolymer and emulsifying them.

The emulsifier is not particularly limited, and for example, an anionic surfactant, a nonionic surfactant, a cationic surfactant, a positive surfactant and the like can be used.

Of these, anionic surfactants selected from the group consisting of alkylbenzenesulfonic acid salts, aliphatic sulfonic acid salts, sulfuric acid ester salts of higher alcohols,? -Olefin sulfonic acid salts, and alkyl ether sulfuric acid ester salts are particularly preferably used. The amount of the emulsifier to be used is preferably 0.3 to 10 parts by weight, more preferably 0.8 to 8 parts by weight, and most preferably 1.5 to 6 parts by weight, based on 100 parts by weight of the monomer constituting the carboxylic acid-modified nitrile- Is used. If the amount of the emulsifier is less than 0.3 parts by weight, the stability during polymerization tends to deteriorate. If the amount is more than 10 parts by weight, foaming becomes more frequent, and it is difficult to produce a dip molded article.

The polymerization initiator is not particularly limited, but a radical initiator can be preferably used. Examples of the radical initiator include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium persulfate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-menthol hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide Organic peroxides such as oxides, 3,5,5, -trimethylhexanol peroxide, t-butyl peroxyisobutyrate; At least one member selected from the group consisting of azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobisisobutyric acid (butyl acid) methyl, Inorganic peroxides are more preferable, and persulfates are particularly preferably used. The amount of the polymerization initiator to be used is preferably 0.01 to 2 parts by weight, more preferably 0.02 to 1.5 parts by weight, based on 100 parts by weight of the total monomer constituting the carboxylic acid-modified nitrile-based copolymer. If the amount of the polymerization initiator is less than 0.01 part by weight, the polymerization rate is lowered and the final product is difficult to produce. If the amount is more than 2 parts by weight, the polymerization rate becomes too fast and it is difficult to control the polymerization.

The activating agent may be selected from the group consisting of sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, dextrose, sodium pyrophosphate, and sodium sulfite.

Examples of the molecular weight regulator include, but are not limited to, mercaptans such as? -Methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, and octyl mercaptan; Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, and methylene bromide; Containing sulfur compounds such as tetraethylthiuram disulfide, dipentamethylenethiuramdisulfide, diisopropylkisantigen disulfide, and the like. These molecular weight modifiers can be used alone or in combination of two or more. Of these, mercaptans are preferable, and t-dodecyl mercaptan can be more preferably used. The amount of the molecular weight modifier to be used varies depending on the kind thereof, but is preferably 0.1 to 2 parts by weight, more preferably 0.2 to 1.5 parts by weight, more preferably 0.2 to 1.5 parts by weight, Preferably 0.3 to 1.0 part by weight. If the amount of the molecular weight modifier is less than 0.1 parts by weight, the physical properties of the dip-molded article are markedly deteriorated. If the amount is more than 2 parts by weight, the polymerization stability is lowered.

Further, it is of course possible to further add a chelating agent, a dispersant, a pH adjuster, an oxygen scavenger, a particle size regulator, an anti-aging agent, and an oxygen scavenger in the polymerization of the latex of the present invention.

The method of introducing the monomer mixture constituting the carboxylic acid-modified nitrile-based copolymer is not particularly limited, and a method of charging the monomer mixture into the polymerization reactor at one time, a method of continuously introducing the monomer mixture into the polymerization reactor, A method in which the monomer is introduced into a polymerization reactor and the remaining monomers are continuously supplied to a polymerization reactor.

The polymerization temperature during the emulsion polymerization is not particularly limited, but is usually 10 to 90 占 폚, preferably 25 to 75 占 폚. The conversion rate when the polymerization reaction is stopped is preferably 90% or more, and more preferably 93% or more. The unreacted monomer is removed and the solid content and pH are adjusted to obtain a carboxylic acid-modified nitrile-based copolymer latex.

The average particle diameter of the latex of the present invention is preferably 80 to 220 nm, more preferably 100 to 200 nm. When the average particle diameter is 100 nm or less, the viscosity of the latex is increased. When the average particle diameter is 200 nm or more, the polymerization stability is deteriorated and productivity is low, which is not preferable. The average particle diameter can be adjusted depending on the type and content of the above emulsifier.

The average particle size of the latex was measured with a Laser Scattering Analyzer (Nicomp).

2. Latex composition for deep molding

The carboxylic acid-modified nitrile-based copolymer latex of the present invention obtained by the above-mentioned method comprises at least one additive selected from the group consisting of a vulcanizing agent, an ionic crosslinking agent, a pigment, a filler, a thickener and a pH regulator, Can be prepared.

A latex composition for dip molding is prepared comprising a common additive used in a composition for dip molding such as an ionic crosslinking agent, a pigment such as titanium oxide, a filler such as silica, a thickener, and a pH controlling agent such as ammonia or alkali hydroxide.

It is preferable that the carboxylic acid-modified nitrile-based copolymer latex is contained in the composition in an amount of 80 to 99% by weight, preferably 85 to 98% by weight, and most preferably 88 to 97% by weight, In terms of physical properties of the glove.

The solid concentration of the latex composition for dip molding of the present invention is preferably 10 to 40% by weight, more preferably 15 to 35% by weight, and most preferably 18 to 33% by weight. The pH of the latex composition for dip molding of the present invention is preferably 8.0 to 12, more preferably 9 to 11, and most preferably 9.3 to 10.5.

3. Dip molded products

As a dip molding method for obtaining the dip-shaped article of the present invention, a usual method can be used, and examples thereof include a direct dipping method, an anode adhesion dipping method, and a Teague adhesion dipping method. Of these, the positive electrode deposition dipping method is preferable because of the advantage of easily obtaining a dip-shaped article having a uniform thickness.

Hereinafter, a method for producing a dip-molded article using the latex composition of the present invention will be described in detail.

(a) immersing a hand shaped dip forming mold in a coagulant solution and attaching a coagulant to the surface of the dip forming mold

Examples of coagulants include metal halides such as barium chloride, calcium chloride, magnesium chloride, zinc chloride and aluminum chloride, and the like; Nitrates such as barium nitrate, calcium nitrate and zinc nitrate; Acetic acid salts such as barium acetate, calcium acetate and zinc acetate; Calcium sulfate, magnesium sulfate, and sulfate such as aluminum sulfate. Of these, calcium chloride and calcium nitrate are preferred. The coagulant solution is a solution in which the above coagulant is dissolved in water, alcohol or a mixture thereof. The concentration of the coagulant in the coagulant solution is usually 5 to 75% by weight, preferably 15 to 55% by weight.

(b) immersing a dip molding die with a coagulant on the latex watch composition of the present invention to form a dip molding layer

A dip forming mold having a coagulant attached thereto is dipped in a latex composition for dip molding made of the latex resin composition of the present invention, and then a dip forming mold is taken out to form a dip forming layer in a dip forming mold.

(c) crosslinking the latex resin by heat-treating the dip molding layer formed in the dip molding die

At the time of the heat treatment, the water component first evaporates and crosslinking is performed. Subsequently, the dip-molded layer bridged by heat treatment is peeled off from the dip-molded product to obtain a dipped molded article.

(d) measuring the physical properties of the obtained dip-molded article

A dumbbell-shaped test piece was produced from the obtained dip-molded article in accordance with ASTM D-412. Subsequently, the test piece was pulled at a stretching speed of 500 mm / min using a universal testing machine (UTM), and the tensile strength and elongation at break were measured, and the tactile sensation was measured by the stress when the elongation was 300%. The higher the tensile strength and elongation, the better the quality of the dip product, and the lower the stress value when the elongation is 300%, the better the quality of the deep-molded product is.

First, a hand shaped dip forming die is immersed in a coagulating agent solution, and a coagulant is attached to the surface of the dipping forming die. Examples of coagulants include metal halides such as barium chloride, calcium chloride, magnesium chloride, zinc chloride and aluminum chloride, and the like; Nitrates such as barium nitrate, calcium nitrate and zinc nitrate; Acetic acid salts such as barium acetate, calcium acetate and zinc acetate; Calcium sulfate, magnesium sulfate, and sulfate such as aluminum sulfate. Of these, calcium chloride and calcium nitrate are preferred. The coagulant solution is a solution in which the above coagulant is dissolved in water, alcohol or a mixture thereof. The concentration of the coagulant in the coagulant solution is usually from 5 to 75% by weight, preferably from 15 to 55% by weight, most preferably from 18 to 40% by weight.

Subsequently, a dip forming mold in which the coagulant is submitted is immersed in a latex composition for dip molding made of the carboxylic acid modified nitrile-based copolymer latex of the present invention, and a dip forming mold is taken out to form a dip molding layer in a dip forming mold. Subsequently, the dip molding layer formed in the dip forming mold is subjected to heat treatment to crosslink the carboxylic acid-modified nitrile-based copolymer latex. During the heat treatment, the physical component first evaporates and vulcanization is carried out through crosslinking. Subsequently, the dip-formed layer crosslinked by the heat treatment is peeled off from the dip forming mold to obtain a dipped molded article.

The process according to the invention can also be used for any latex article which can be produced by a technically known dip-molding process. Specifically, it can be applied to deep-formed latex articles selected from surgical gloves, examination gloves, condoms, catheters or various kinds of health care products such as industrial and household gloves.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

[Example]

Example 1

A 10 L high-pressure reactor equipped with a stirrer, a thermometer, a condenser, an inlet of nitrogen gas, and a monomer, an emulsifier and a polymerization initiator was continuously introduced. The reactor was charged with 25 wt.% Of acrylonitrile, 4 parts by weight of sodium alkylbenzenesulfonate, 0.5 part by weight of t-dodecyl mercaptan, and 140 parts by weight of ion-exchanged water were added to 100 parts by weight of a monomer mixture of 7% by weight and 7% by weight of methacrylic acid.

After the temperature was elevated, 0.3 parts by weight of potassium persulfate as a polymerization initiator was added. When the conversion was 95%, 0.1 part by weight of sodium dimethyldithiocarbamate was added to stop the polymerization. Unreacted monomers were removed through a deodorization process, and ammonia water, an antioxidant, a defoaming agent and the like were added to obtain a carboxylated acrylonitrile-butadiene copolymer latex having a solid concentration of 45% and a pH of 8.5.

The latex has an average particle size of 105 nm as a result of an average particle size analysis, and the latex prepared as above is referred to as 'latex-A'.

Next, a 10 L high-pressure reactor equipped with a stirrer, a thermometer, a condenser, an inlet for nitrogen gas, and a monomer, an emulsifier and a polymerization initiator was continuously introduced. The reactor was charged with 25 wt% of acrylonitrile, 1.5 parts by weight of sodium alkylbenzenesulfonate, 0.5 part by weight of t-dodecyl mercaptan and 140 parts by weight of ion-exchanged water were added to 100 parts by weight of a monomer mixture of 68% by weight of butadiene and 7% by weight of methacrylic acid, .

After the temperature was elevated, 0.2 parts by weight of potassium persulfate as a polymerization initiator was added. When the conversion was 95%, 0.1 part by weight of sodium dimethyldithiocarbamate was added to terminate the polymerization. Unreacted monomers were removed through a deodorization process, and ammonia water, an antioxidant, a defoaming agent and the like were added to obtain a carboxylated acrylonitrile-butadiene copolymer latex having a solid concentration of 45% and a pH of 8.5.

As a result of the average particle size analysis, the latex exhibits an average particle diameter of 187 nm. Hereinafter, the latex prepared as above is referred to as 'latex-B'.

Latex-A and latex-B were mixed at 50:50 to prepare a latex.

(Preparation of composition for dip molding)

A 3% potassium hydroxide solution and an appropriate amount of secondary distilled water were added to the latex to obtain a composition for dip molding having a solid concentration of 25% and a pH of 10.0.

(Dip molded article production)

22 parts by weight of calcium nitrate, 69.5 parts by weight of distilled water, 8 parts by weight of calcium carbonate and 0.5 part by weight of a wetting agent (Teric 320 produced by Huntsman Corporation, Australia) were mixed to prepare a coagulant solution. A hand-shaped ceramic mold was immersed in this solution for 1 minute, pulled out, dried at 80 ° C for 3 minutes, and the coagulant was applied to the hand mold.

Next, the mold coated with the coagulant was immersed in the composition for deep molding for 1 minute, pulled up, dried at 80 DEG C for 1 minute, and immersed in water or hot water for 3 minutes. The mold was again dried at 80 DEG C for 3 minutes and then crosslinked at 130 DEG C for 20 minutes. The crosslinked dip molding layer was peeled off from the hand mold to obtain a glove-shaped dip molded article. The physical properties of this dip-molded article are shown in Table 1.

Example 2

A 10 L high-pressure reactor equipped with a stirrer, a thermometer, a condenser, an inlet of nitrogen gas, and a monomer, an emulsifier and a polymerization initiator was continuously introduced. The reactor was charged with 25 wt.% Of acrylonitrile, 3 parts by weight of sodium alkylbenzenesulfonate, 0.5 part by weight of t-dodecyl mercaptan, and 140 parts by weight of ion-exchanged water were added to 100 parts by weight of a monomer mixture of 7% by weight and 7% by weight of methacrylic acid.

After the temperature was elevated, 0.3 parts by weight of potassium persulfate as a polymerization initiator was added. When the conversion was 95%, 0.1 part by weight of sodium dimethyldithiocarbamate was added to stop the polymerization. Unreacted monomers were removed through a deodorization process, and ammonia water, an antioxidant, a defoaming agent and the like were added to obtain a carboxylated acrylonitrile-butadiene copolymer latex having a solid concentration of 45% and a pH of 8.5.

The latex has an average particle size of 133 nm as a result of an average particle size analysis, and the latex prepared as above is referred to as 'latex-C'.

Next, a 10 L high-pressure reactor equipped with a stirrer, a thermometer, a condenser, an inlet for nitrogen gas, and a monomer, an emulsifier and a polymerization initiator was continuously introduced. The reactor was charged with 25 wt% of acrylonitrile, 1.5 parts by weight of sodium alkylbenzenesulfonate, 0.5 part by weight of t-dodecyl mercaptan and 140 parts by weight of ion-exchanged water were added to 100 parts by weight of a monomer mixture of 68% by weight of butadiene and 7% by weight of methacrylic acid, .

After the temperature was elevated, 0.3 parts by weight of potassium persulfate as a polymerization initiator was added. When the conversion was 95%, 0.1 part by weight of sodium dimethyldithiocarbamate was added to stop the polymerization. Unreacted monomers were removed through a deodorization process, and ammonia water, an antioxidant, a defoaming agent and the like were added to obtain a carboxylated acrylonitrile-butadiene copolymer latex having a solid concentration of 45% and a pH of 8.5.

The latex has an average particle size of 156 nm as a result of an average particle size analysis, and the latex prepared as described above is referred to as a latex-D.

Latex-C and latex-D were mixed at 50:50 to prepare a latex.

In the same manner as in Example 1, a glove-shaped deep-molded product was prepared, and physical properties thereof are shown in Table 1.

Example 3

In the same manner as in Example 1 except that latex-A and latex-B were mixed in a weight ratio of 25:75 in Example 1, a glove-shaped deep-molded product was prepared and physical properties thereof are shown in Table 1.

Example 4

In the same manner as in Example 1 except that latex-A and latex-B were mixed in a weight ratio of 75:25 in Example 1, a glove-shaped deep-molded product was prepared and physical properties thereof are shown in Table 1.

Example 5

A glove-shaped dip-molded article was prepared in the same manner as in Example 1 except that latex-A and latex-D were mixed in a weight ratio of 50:50 in Example 1, and physical properties thereof are shown in Table 1.

Example 6

In the same manner as in Example 1 except that latex-B and latex-C were mixed in a weight ratio of 50:50 in Example 1, a glove-shaped deep-molded product was prepared and physical properties thereof are shown in Table 1.

Comparative Example 1

In the same manner as in Example 1 except that latex-A was used alone in Example 1, a glove-shaped deep-molded product was prepared, and physical properties thereof are shown in Table 1.

Comparative Example 2

In the same manner as in Example 1 except that latex-B was used alone in Example 1, a glove-shaped deep-molded product was prepared, and physical properties thereof are shown in Table 1.

Comparative Example 3

In the same manner as in Example 1 except that latex-C was used alone in Example 1, a glove-shaped deep-molded product was prepared, and physical properties thereof are shown in Table 1.

Comparative Example 4

Dip molded articles in the form of gloves were prepared in the same manner as in Example 1 except that latex-D was used alone in Example 1, and physical properties thereof are shown in Table 1.

Tensile Strength (MPa) Elongation (%) Stress at 300% (MPa) Example 1 32.8 652 3.8 Example 2 33.9 650 3.6 Example 3 28.2 612 3.2 Example 4 30.1 624 3.3 Example 5 32.6 624 4.0 Example 6 35.0 654 3.6 Comparative Example 1 25.8 582 3.3 Comparative Example 2 21.9 549 3.3 Comparative Example 3 23.9 574 3.5 Comparative Example 4 22.0 588 3.2

Based on the results of the above table, a dip molded article made from a carboxylic acid modified nitrile latex in which a latex having a large average particle diameter and a small latex are mixed has excellent physical properties such as tensile strength and elongation.

Claims (15)

Wherein the carboxylic acid-modified nitrile-based copolymer latex comprises 45 to 80% by weight of a conjugated diene-based monomer, 15 to 45% by weight of an ethylenically unsaturated nitrile-based monomer %, And the ethylenic unsaturated acid monomer is polymerized in an amount of 0.1 to 10% by weight based on the total weight of the latex. The carboxylic acid-modified nitrile-based copolymer latex according to claim 1, wherein the two different carboxylic acid modified nitrile-based copolymer latexes having different average particle diameters have an average particle diameter of the latex of 100 nm to 140 nm and 150 nm to 200 nm, respectively. The carboxylic acid-modified nitrile-based copolymer latex according to claim 1, wherein the weight ratio of the two carboxylic acid modified nitrile-based copolymer latexes having different average particle diameters is 10:90 to 90:10. delete The conjugated diene-based monomer according to claim 1, wherein the conjugated diene-based monomer is at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and isoprene Wherein the at least one carboxylic acid-modified nitrile-based copolymer latex is at least one selected from the group consisting of the following. The method according to claim 1, wherein the ethylenically unsaturated nitrile monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, fumaronitrile,? -Chloronitrile and? -Cyanoethyl acrylonitrile By weight of a carboxylic acid-modified nitrile-based copolymer latex. The composition of claim 1 wherein said ethylenically unsaturated acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, citraconic anhydride, styrenesulfonic acid, monobutyl fumarate, monobutyl maleate, -Hydroxypropyl, and the carboxylic acid-modified nitrile-based copolymer latex is at least one selected from the group consisting of hydroxypropyl. [Claim 2] The method of claim 1, wherein the carboxylic acid-modified nitrile-based copolymer latex is prepared by reacting the ethylenically unsaturated nitrile-based monomer and the ethylenic unsaturated acid monomer with an ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated nitrile- Wherein the latex further comprises at least 20% by weight of the monomer. The copolymer according to claim 8, wherein the copolymerizable ethylenically unsaturated monomer is at least one selected from the group consisting of a vinyl aromatic monomer, a fluoroalkyl vinyl ether, an ethylenically unsaturated amide monomer, a non-conjugated diene monomer and an ethylenically unsaturated carboxylic acid ester monomer By weight of a carboxylic acid-modified nitrile-based copolymer latex. The latex according to claim 1, wherein the latex comprises 0.3 to 10 parts by weight of an emulsifier, 0.01 to 2 parts by weight of a polymerization initiator, and 0.1 to 2 parts by weight of a molecular weight adjuster, based on 100 parts by weight of total monomers constituting the carboxylic acid modified nitrile- By weight of a carboxylic acid-modified nitrile-based copolymer latex. A latex composition for dip molding, which comprises a carboxylic acid-modified nitrile-based copolymer latex according to any one of claims 1 to 3 or 5 to 10. The latex composition for deep molding according to claim 11, wherein the carboxylic acid-modified nitrile-based copolymer latex is contained in 80 to 99% by weight of the total composition. The latex composition for deep molding according to claim 11, wherein the composition comprises at least one additive selected from the group consisting of a vulcanizing agent, an ionic cross-linking agent, a pigment, a filler, a thickener and a pH adjuster. A deep-formed product obtained by dip-molding the latex composition for dip molding according to any one of claims 11 to 13. 15. The dip molded article of claim 14, wherein the dip-molded article is a glove, a test glove, a condom, a catheter, or a health care article.