KR102251967B1 - A latex composition for dip-forming, a method for preparing thereof, and a dip-formed article prepared therefrom - Google Patents

Abstract

An embodiment of the present invention provides a latex composition for dip molding, comprising a carboxylic acid-modified nitrile-based copolymer latex, a polyvinylpyrrolidone-based resin, and a filler.

Description

Latex composition for dip molding, its manufacturing method, and dip-formed products manufactured therefrom {A LATEX COMPOSITION FOR DIP-FORMING, A METHOD FOR PREPARING THEREOF, AND A DIP-FORMED ARTICLE PREPARED THEREFROM}

The present invention relates to a latex composition for dip molding, a method for producing the same, and a dip molded article prepared therefrom.

The main raw material of gloves used for conventional medical, agricultural and livestock processing, and industrial use was natural rubber latex. However, in the case of using a glove made from natural rubber latex, a problem in which the user of the glove suffers from contact allergic disease due to the protein contained in the natural rubber latex occurs frequently.

Accordingly, attempts have been made to manufacture a raw material for gloves that can replace natural rubber latex. For example, attempts have been made to manufacture gloves by applying a synthetic rubber latex that does not contain protein, such as a nitrile-based copolymer latex. Compared to natural rubber latex gloves, nitrile-based copolymer latex gloves have a higher puncture strength, and thus, demand is increasing in medical or food fields where contact with sharp objects occurs frequently. However, until now, the puncture strength, tensile strength, elongation, etc. implemented in the nitrile-based copolymer latex gloves clearly have limitations.

On the other hand, Patent Publication No. 10-1964278 discloses an invention titled "latex composition for dip molding and a dip molded article manufactured therefrom". The latex composition for dip molding includes an alkenyl succinic acid-based emulsifier, and the dip-molded article prepared therefrom has improved tensile strength.

Korean Patent Application Publication No. 10-2017-0081839 discloses an invention entitled "latex composition for dip molding and a molded article manufactured therefrom". The latex composition for dip molding includes an emulsifier composed of a triblock copolymer, and the dip-molded article prepared therefrom has improved tensile strength to elongation.

Korean Patent Publication No. 10-2018-0051147 discloses an invention entitled "latex composition for dip molding and a molded article manufactured therefrom". The latex composition for dip molding includes polyethylene glycol, and the dip-molded article prepared therefrom has improved tensile strength and elongation.

The above inventions improve the physical properties of the dip-molded product by adding a special emulsifier or using a modified monomer, but there is a limitation in that the mechanical properties cannot be improved in a balanced way.

And, in the manufacturing process of the nitrile-based copolymer glove, in the dip molding process, the nitrile-based copolymer latex is a halide-based calcium chloride (CaCl ₂ ), magnesium chloride (MgCl _{2 ).} ), barium chloride (BaCl ₂ ), or nitrate-based calcium nitrate (calcium nitrate, Ca(NO ₃ ) ₂ ), magnesium nitrate (magnesium nitrate, Mg(NO ₃ ) ₂ ), etc. There is a problem that the chemical stability of the latex is rapidly deteriorated as it is exposed to the cationic coagulant for a long time. This lowers the productivity as well as mechanical properties of the nitrile-based copolymer glove.

The present invention is to solve the problems of the prior art described above, and an object of the present invention is to improve the productivity of dip molded products by preventing the chemical stability of the nitrile latex composition for dip molding from deteriorating, and to improve the productivity of the dip molding nitrile-based latex composition. When a dip molded article is manufactured using a latex composition, it is to provide a dip molded article having mechanical properties such as excellent tensile strength and elongation.

One aspect of the present invention provides a latex composition for dip molding, comprising a carboxylic acid-modified nitrile-based copolymer latex, a polyvinylpyrrolidone-based resin, and a filler.

In one embodiment, the carboxylic acid-modified nitrile-based copolymer latex, based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex, 45 to 80% by weight of a conjugated diene-based monomer; 15 to 45% by weight of ethylenically unsaturated nitrile monomer; And 1 to 10% by weight of an ethylenically unsaturated acid monomer.

In one embodiment, the conjugated diene-based monomer is 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, isoprene, and these It may be one selected from the group consisting of a combination of two or more of them.

In one embodiment, the ethylenically unsaturated nitrile monomer is selected from the group consisting of acrylonitrile, methacrylonitrile, hummaronitrile, α-chloronitrile, α-cyano ethyl acrylonitrile, and combinations of two or more thereof It can be one that becomes.

In one embodiment, the ethylenically unsaturated acid monomer is acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, citraconic anhydride, styrene sulfonic acid, monobutyl fumarate, monobutyl maleate, mono-2 maleic acid -It may be one selected from the group consisting of hydroxy propyl and a combination of two or more of them.

In one embodiment, the content of the polyvinylpyrrolidone-based resin may be 0.1 to 3 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex.

In one embodiment, the content of the filler may be 0.1 to 5 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex.

In one embodiment, the polyvinylpyrrolidone-based resin comprises one monomer selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate, and combinations of two or more thereof. It may contain 20 to 80% by weight based on the total weight of the polyvinylpyrrolidone-based resin.

In one embodiment, the average particle diameter of the filler may be 10 to 200 nm.

In one embodiment, the weight average molecular weight of the polyvinylpyrrolidone resin may be 5,000 to 50,000 g/mol.

In one embodiment, the filler may be one selected from the group consisting of silica, fumed silica, precipitated silica, silica sol, and a combination of two or more of them.

In one embodiment, the dip molding latex composition may further include one selected from the group consisting of a pigment, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, and a combination of two or more of them.

In one embodiment, the carboxylic acid-modified nitrile-based copolymer latex is one selected from the group consisting of an emulsifier, a polymerization initiator and a molecular weight control agent, a polymerization terminator, a pH control agent, an antioxidant, an oxygen trapping agent, and a combination of two or more thereof. It may contain more.

Another aspect of the present invention is (a) emulsion polymerization of a mixture of a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer to obtain a carboxylic acid-modified nitrile-based copolymer latex; And (b) mixing an aqueous solution of a polyvinylpyrrolidone resin and an aqueous filler solution with the product of step (a).

Another aspect of the present invention provides a dip molded article obtained by dip molding the latex composition for dip molding.

In one embodiment, the dip-molded product may be one selected from the group consisting of medical gloves, agricultural and livestock processing gloves, and industrial gloves.

By preventing the chemical stability of the nitrile-based latex composition for dip molding according to the present invention from deteriorating, productivity of the dip-molded product is improved, and when a dip-molded product is manufactured using the nitrile-based latex composition for dip molding, excellent tensile strength, Mechanical properties such as elongation can be implemented.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be deduced from the configuration of the invention described in the detailed description or claims of the present invention.

The present invention may be implemented in a number of different forms, and therefore is not limited to the embodiments described herein.

Throughout the specification, when a part is said to be "connected" with another part, this includes not only "directly connected" but also "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, this means that other components may be further provided, not excluding other components, unless specifically stated to the contrary.

When a range of numerical values is described herein, the value has the precision of significant figures provided according to the standard rules in chemistry for significant figures, unless a specific range thereof is stated otherwise. For example, 10 includes a range of 5.0 to 14.9, and the number 10.0 includes a range of 9.50 to 10.49.

As used herein, the term "primary particle" refers to a one-dimensional or more particle having an average particle size of 1 to 100 nm. In this regard, "secondary particle" means a particle formed by agglomeration of the primary particles. In this case, the secondary particles may be formed by physical or chemical bonds such as van der Waals bonds and covalent bonds.

Latex composition for dip molding

The latex composition for dip molding according to an aspect of the present invention may include a carboxylic acid-modified nitrile-based copolymer latex, a polyvinylpyrrolidone-based resin, and a filler.

The carboxylic acid-modified nitrile-based copolymer latex, based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex, 45 to 80% by weight of a conjugated diene-based monomer; 15 to 45% by weight of ethylenically unsaturated nitrile monomer; And 1 to 10% by weight of an ethylenically unsaturated acid monomer.

As a non-limiting example of the present invention, the content of the conjugated diene-based monomer is 45% by weight or more, 50% by weight or more, or 55% by weight or more, based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex, and 80 It may be less than or equal to 75%, or less than or equal to 70% by weight. If the content of the conjugated diene-based monomer is less than 45% by weight, the dip-molded product may be excessively cured to reduce the fit of the user of the dip-molded product. This may decrease and the tensile strength may be lowered.

As a non-limiting example of the present invention, the content of the ethylenically unsaturated nitrile monomer is 15% by weight or more, 20% by weight or more, or 25% by weight or more, based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex, It may be 45% by weight or less, 40% by weight or less, or 35% by weight or less. If the content of the ethylenically unsaturated nitrile monomer is less than 15% by weight, the oil resistance of the dip-molded product may decrease and the tensile strength may decrease. When the content of the ethylenically unsaturated nitrile monomer exceeds 45% by weight, the dip-molded product may be excessively cured, thereby reducing the user's wearing comfort.

As a non-limiting example of the present invention, the content of the ethylenically unsaturated acid monomer is 1% by weight or more, 2% by weight or more, or 3% by weight or more, based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex, It may be 10% by weight or less, 9% by weight or less, or 8% by weight or less. If the content of the ethylenically unsaturated acid monomer is less than 1% by weight, the tensile strength of the dip molding may be reduced. When the content of the ethylenically unsaturated nitrile monomer exceeds 10% by weight, the dip-molded product may be excessively cured and thus the user of the dip-molded product may deteriorate the fit.

As a non-limiting example of the present invention, the carboxylic acid-modified nitrile-based copolymer latex may be a copolymer represented by Formula 1 below.

[Formula 1]

Formula 1 is a general example of a conjugated diene monomer unit, an ethylenically unsaturated nitrile monomer unit, and an ethylenically unsaturated acid monomer unit, which are three constituent units of the carboxylic acid-modified nitrile copolymer latex. It is not limited. In addition, Formula 1 shows each unit in order for convenience, and in the copolymer, each unit is mixed and distributed randomly regardless of the order of Formula 1, or at least part of the copolymer is divided into block units according to the needs of the user. It may be distributed.

The ratio of a, b, and c may be adjusted according to the ratio of each monomer unit constituting the copolymer.

The conjugated diene-based monomer is composed of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, isoprene, and combinations of two or more of them. It may be one selected from the group, preferably, 1,3-butadiene (buta-1,3-diene), but is not limited thereto.

The ethylenically unsaturated nitrile monomer may be one selected from the group consisting of acrylonitrile, methacrylonitrile, hummaronitrile, α-chloronitrile, α-cyano ethyl acrylonitrile, and combinations of two or more thereof, Preferably, it may be acrylonitrile (prop-2-enenitrile), but is not limited thereto.

The ethylenically unsaturated acid monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, citraconic anhydride, styrene sulfonic acid, monobutyl fumarate, monobutyl maleate, mono-2-hydroxy propyl maleic acid, and these It may be one selected from the group consisting of a combination of two or more of them, and preferably, may be methacrylic acid (2-methylprop-2-enoic acid), but is not limited thereto.

As a non-limiting example of the present invention, the polyvinylpyrrolidone resin may be a block copolymer represented by Formula 2 below. In this case, the ratio of n to m may be 1 to 1.5.

[Formula 2]

The content of the polyvinylpyrrolidone-based resin may be 0.1 to 3 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. At this time, the content of the polyvinylpyrrolidone-based resin is 0.1 parts by weight or more, 0.3 parts by weight or more, or 0.5 parts by weight or more, 3 parts by weight or less, 2.8 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. It may be less than or equal to 2.6 parts by weight or less.

The content of the filler may be 0.1 to 5 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. At this time, the content of the filler is 0.1 parts by weight or more, 0.3 parts by weight or more, or 0.5 parts by weight or more, 5 parts by weight or less, 4.8 parts by weight or less, or It may be less than 4.6 parts by weight.

The polyvinylpyrrolidone-based resin includes one monomer selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate, and combinations of two or more of them. It may contain 20 to 80% by weight based on the total weight, preferably, but may be vinyl acetate, but is not limited thereto. Polyvinylpyrrolidone-based resin has excellent compatibility with carboxylic acid-modified nitrile-based copolymer latex and exhibits acid resistance to improve the chemical stability of the latex particles, as well as excellent dispersibility with nanoparticle oxides, resulting in chemical stability of the latex particles. In addition to improvement, it is possible to improve mechanical properties such as tensile strength of dip-molded products at the same time.

As a non-limiting example of the present invention, the content of the first monomer is 20% by weight or more, 30% by weight or more, 40% by weight or more, and 80% by weight or less, based on the total weight of the polyvinylpyrrolidone-based resin, It may be 70% by weight or less, or 60% by weight or less.

The average particle diameter of the filler may be 10 to 200 nm. These filler particles may include primary particles to secondary particles. In this case, the average particle diameter of the filler may be 10 nm or more, 15 nm or more, or 20 nm or more, and may be 200 nm or less, 195 nm or less, or 190 nm or less. The average particle diameter of the filler may mean the particle diameter of the primary particles, but is not limited thereto.

The weight average molecular weight of the polyvinylpyrrolidone-based resin may be 5,000 to 50,000 g/mol. The weight average molecular weight of the polyvinylpyrrolidone-based resin is 5,000 g/mol or more, 6,000 g/mol or more, or 7,000 g/mol or more, 50,000 g/mol or less, 49,000 g/mol or less, or 48,000 g/mol or less. I can.

The filler may be one selected from the group consisting of silica, fumed silica, precipitated silica, silica sol, and a combination of two or more of them, and preferably, may be fumed silica, but is not limited thereto.

The latex composition for dip molding may further include one selected from the group consisting of a pigment such as titanium dioxide, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent such as zinc oxide, and a combination of two or more of them.

As a non-limiting example of the present invention, the vulcanizing agent may include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, surface treated sulfur, and insoluble sulfur. Such a vulcanizing agent attacks the pi bonds in the conjugated double bonds of butadiene to cross-link between polymer chains, thereby not only imparting elasticity to the copolymer, but also improving the chemical resistance of the dip-molded product.

As a non-limiting example of the present invention, the vulcanization accelerator is 2-mercaptobenzothiazole, 2,2-dithiobisbenzothiazole-2-sulfenamide, N-cyclohexylbenzothiazole-2-sulfenamide, 2-morpholinothiobenzothiazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, diphenylguanidine, di-o-tolyl It may be one selected from guanidine and a combination of two or more of them, and preferably, zinc dibutylthiocarbamate (ZDBC), but is not limited thereto.

The carboxylic acid-modified nitrile-based copolymer latex may further include one selected from the group consisting of an emulsifier, a polymerization initiator and a molecular weight control agent, a polymerization terminator, a pH control agent, an antioxidant, an oxygen trapping agent, and a combination of two or more of them.

As a non-limiting example of the present invention, the emulsifier may be one of an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant, and preferably, an alkylbenzene sulfonate salt, which is an anionic surfactant. , An aliphatic sulfonate, a sulfate ester salt of a higher alcohol, an α-olefin sulfonate salt, an alkyl ether sulfate ester salt, and more preferably, sodium alkylbenzene sulfonate, but limited thereto. It does not become. These emulsifiers may be used in an amount of 0.8 to 8 parts by weight based on 100 parts by weight of the monomer mixture.

As a non-limiting example of the present invention, the polymerization initiator is an inorganic peroxide selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-tanhydro peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide An organic peroxide selected from the group consisting of oxide, 3,5,5-trimethylhexanol peroxide, and t-butylperoxy isobutylate; It may be one of azobis isobutyronitrile, azobis-2,4-dimethyl valeronitrile, azobiscyclohexanecarbonitrile, and azobisisobutyric acid (butyric acid) methyl, preferably potassium persulfate (potassium persulfate), but is not limited thereto. This polymerization initiator may be used in an amount of 0.02 to 1.5 parts by weight based on 100 parts by weight of the monomer mixture.

As a non-limiting example of the present invention, the molecular weight modifier may include mercaptans such as α-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 tetraethyl thiuram disulfide, dipentamethylene thiuram disulfide, and diisopropylxanthogen disulfide; It may be one of, and preferably, t-dodecyl mercaptan, but is not limited thereto. This molecular weight modifier may be used in an amount of 0.2 to 0.7 parts by weight based on 100 parts by weight of the monomer mixture.

As a non-limiting example of the present invention, the polymerization terminator is hydroxyl amine, hydroxy amine sulfate, diethyl hydroxy amine, hydroxy amine sulfonic acid and its alkali metal ion, sodium dimethyldithiocarbamate, hydroquinone derivative , Hydroxy diethyl benzene dithio carboxylic acid, hydroxy dibutyl benzene dithio carboxylic acid, and the like, may be one of aromatic hydroxy dithio carboxylic acids, preferably sodium dimethyldithiocarbamate. However, it is not limited thereto.

As a non-limiting example of the present invention, it may be desirable to adjust the hydrogen ion concentration index of the latex composition for dip molding to pH 9 to 11 by adding the pH adjusting agent. As such a pH adjuster, 1 to 5% by weight of potassium hydroxide aqueous solution or 1 to 5% by weight of aqueous ammonia may be used. At this time, the solid content of the pH adjusting agent may be 40 to 50% by weight, preferably, 40% by weight or more, 42% by weight or more, or 44% by weight or more, 50% by weight or less, 48% by weight or less, or It may be up to 46% by weight.

Manufacturing method of latex composition for dip molding

A method of preparing a latex composition for dip molding according to another aspect of the present invention includes (a) a carboxylic acid-modified nitrile-based copolymer by emulsion polymerization of a mixture of a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer. Obtaining a coalescence latex; And (b) mixing an aqueous solution of a polyvinylpyrrolidone resin and an aqueous filler solution with the product of step (a).

As a non-limiting example of the present invention, the polyvinylpyrrolidone resin may be prepared by spray drying. In addition, when only the polyvinylidene-based resin is added and the aqueous filler solution is not added, the tensile strength of the dip-molded product may decrease.

As a non-limiting example of the present invention, in the aqueous filler solution, the content of the filler may be 3 to 40% by weight based on the total weight of the aqueous solution. In this case, the content of the filler may be 3% by weight or more, 40% by weight or less, 35% by weight or less, or 30% by weight or less. In addition, the aqueous filler solution may include one in the form of a silica sol in which the content of silica is 10 to 50% by weight based on the total weight of the silica sol. In this case, the content of silica may be 10% by weight or more, 15% by weight or more, or 20% by weight or more, and may be 50% by weight or less, 45% by weight or less, or 40% by weight or less.

As a non-limiting example of the present invention, the mixing reaction in step (b) may be performed at 25 to 75°C, and it may be preferable to stop the polymerization reaction when the conversion rate of the reactant is 93% or more.

As a non-limiting example of the present invention, the solid content concentration of the polyvinylpyrrolidone-based resin aqueous solution introduced in step (b) may be 10 to 40% by weight based on the total weight of the aqueous solution. At this time, the solid content concentration of the polyvinylpyrrolidone-based resin may be 10% by weight or more, 15% by weight or more, or 20% by weight or more, and 40% by weight or less, 35% by weight or less, or 30% by weight or less.

Dip molded product

The dip molded article according to another aspect of the present invention may be obtained by dip molding the latex composition for dip molding.

The dip molded product may be one selected from the group consisting of medical gloves, agricultural and livestock processing gloves, and industrial gloves.

Hereinafter, an embodiment of the present invention will be described in detail.

Manufacturing Example 1

An agitator, a thermometer, a cooler, and a nitrogen gas inlet were provided, and a 10 L high-pressure reactor was prepared so that each component can be continuously injected. In a nitrogen atmosphere, a monomer mixture containing 61.5% by weight of 1,3-butadiene, 32% by weight of acrylonitrile, and 6.5% by weight of methacrylic acid was added to the reactor based on the total weight of the mixture. Thereafter, in the reactor, 2 parts by weight of sodium alkylbenzene sulfonate, 0.5 parts by weight of t-dodecyl mercaptan, and 140 parts by weight of ion-exchanged water based on 100 parts by weight of the monomer mixture. It was added in parts by weight. Then, after raising the temperature of the reactor to about 40° C., 0.3 parts by weight of potassium persulfate was added.

When the conversion rate of 1,3-butadiene reached about 95%, 0.1 part by weight of sodium dimethyldithiocarbamate was added to stop the polymerization reaction. Thereafter, the unreacted monomer was removed through a deodorization process, and ammonia water, an antioxidant, an antifoaming agent, and the like were added to prepare a carboxylic acid-modified nitrile-based copolymer latex.

The solid content concentration of the carboxylic acid-modified nitrile-based copolymer latex was measured as 45% by weight based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex, and the hydrogen ion concentration index was measured as pH 8.0.

Manufacturing Example 2

A polyvinylpyrrolidone polymer having a weight average molecular weight of 7,000-11,000 g/mol was added to a 1 L container and stirred with secondary distilled water at 2,000 RPM for 1 hour, thereby preparing an aqueous polyvinylpyrrolidone solution. At this time, the amount of polyvinylpyrrolidone was calculated so that the solid content concentration was 20% by weight based on the total weight of the aqueous solution.

In addition, polyvinylpyrrolidone-vinyl acetate copolymer having a vinyl acetate content of 40% by weight based on the total weight of the copolymer was added to a 1 L container and stirred with secondary distilled water at 2,000 RPM for 1 hour, A polyvinylpyrrolidone-vinyl acetate copolymer aqueous solution was prepared. At this time, the amount of polyvinylpyrrolidone-vinyl acetate copolymer was calculated so that the solid content concentration was 20% by weight based on the total weight of the aqueous solution.

Manufacturing Example 3

Fumed silica particles were added to a 1 L container, and stirred with secondary distilled water at 1,500 RPM for 6 hours using a bead mill to prepare a fumed silica aqueous solution. At this time, the fumed silica was used in which the particle diameter of the primary particles was 20 to 30 nm, and the amount of fumed silica was calculated so that the solid content concentration was 5% by weight based on the total weight of the aqueous solution.

Comparative Example 1

After adding the carboxylic acid-modified nitrile-based copolymer latex according to Preparation Example 1 and the polyvinylpyrrolidone-vinyl acetate copolymer aqueous solution according to Preparation Example 2 to the reactor, using a high-speed stirrer at 4,000 RPM for 10 minutes By stirring, a carboxylic acid-modified nitrile-based copolymer latex containing an additive was prepared.

At this time, the amount of the polyvinylpyrrolidone-vinyl acetate copolymer aqueous solution was calculated so that 0.25 parts by weight of the solid content of the polyvinylidone-vinyl acetate copolymer was added based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex.

Thereafter, a carboxylic acid-modified nitrile-based copolymer latex in which the additive is mixed in a 2 L plastic container, 40% by weight sulfur aqueous solution, 40% by weight zinc dibutyldithiocarbamate (ZDBC) hydrate, 40% by weight zinc oxide An aqueous solution, 40% by weight titanium dioxide aqueous solution, 4% by weight potassium hydroxide aqueous solution, and secondary distilled water were added to obtain a latex composition for dip molding.

At this time, 400 g of carboxylic acid-modified nitrile-based copolymer latex mixed with the above additives, aqueous sulfur solution 11.25 g, ZDBC hydrate 6.75 g, zinc oxide aqueous solution 11.25 g, titanium dioxide aqueous solution 11.25 g, potassium hydroxide aqueous solution 1,350 g, secondary distilled water 474.8 g was added.

The solid content concentration of the dip molding latex composition was measured as 20% by weight based on the total weight of the dip molding latex composition, and the hydrogen ion concentration index was measured as pH 10.

Examples 1-6

In a reactor, the carboxylic acid-modified nitrile-based copolymer latex according to Preparation Example 1, the polyvinylpyrrolidone aqueous solution or polyvinylpyrrolidone-vinyl acetate copolymer aqueous solution according to Preparation Example 2, and fumed silica according to Preparation Example 3 An aqueous solution was added and stirred at 4,000 RPM for 10 minutes using a high-speed stirrer, thereby preparing a carboxylic acid-modified nitrile-based copolymer latex mixed with an additive.

In this case, the amount of the polyvinylpyrrolidone aqueous solution or the polyvinylpyrrolidone-vinyl acetate copolymer aqueous solution added is polyvinylpyrrolidone (PVP) or polyvinylidone based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. -It was calculated so that 0.25 parts by weight of the solid content of the vinyl acetate copolymer (PVA) was added.

In addition, the fumed silica aqueous solution was used with a solid content concentration of 30% by weight based on the total weight of the aqueous solution, and the amount of the fumed silica aqueous solution was 0.5 to 0.7% by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. It was calculated to be added.

Thereafter, a carboxylic acid-modified nitrile-based copolymer latex in which the additive is mixed in a 2 L plastic container, 4.5 g of a sulfur aqueous solution having a sulfur content of 40% by weight, 2.7 g of a ZDBC hydrate having a content of ZDBC of 40% by weight, and zinc oxide. 6.3 g of an aqueous solution of zinc oxide having a content of 40% by weight, 4.5 g of an aqueous solution of titanium dioxide having a content of 40% by weight of titanium dioxide, 54 g of an aqueous potassium hydroxide solution having a content of 4% by weight of potassium hydroxide, and 474.8 g of secondary distilled water were added. A latex composition for dip molding was obtained.

The solid content concentration of the dip molding latex composition was measured as 20% by weight based on the total weight of the dip molding latex composition, and the hydrogen ion concentration index was measured as pH 10.

Table 1 below summarizes the latex components introduced in Comparative Example 1 and Examples 1 to 6.

division Carboxylic acid-modified nitrile-based copolymer latex PVP PVA Fumed silica Comparative Example 1 100 0 0.25 0 Example 1 100 0.25 0 0.5 Example 2 100 0.25 0 0.6 Example 3 100 0.25 0 0.7 Example 4 100 0 0.25 0.5 Example 5 100 0 0.25 0.6 Example 6 100 0 0.25 0.7 * Unit: Carboxylic acid-modified nitrile copolymer latex (parts by weight) PVP (parts by weight) PVA (parts by weight) fumed silica (parts by weight)

Hereinafter, embodiments of the present invention will be described in more detail. However, the following experimental results are only representative of the above examples, and the scope and contents of the present invention are reduced or limited by the examples, and thus cannot be interpreted. Effects of each of the various embodiments of the present invention that are not explicitly presented below will be specifically described in the corresponding section.

Experimental Example 1

Chemical stability of the latex composition for dip molding was analyzed by measuring the aggregation time of the latex composition for dip molding according to Comparative Examples 1 and 1 to 6 of the present invention. In this case, the aggregation time refers to the time from the time when the calcium chloride aqueous solution is added dropwise to the time when the latex composition for dip molding starts to aggregate.

Specifically, 2 g of the latex composition for dip molding according to Comparative Examples 1 and 1 to 6 of the present invention was added to a 300 mL beaker, and then 200 g of secondary distilled water was added, followed by stirring at 200 RPM for 1 hour. Thereafter, a calcium chloride aqueous solution having a calcium chloride content of 0.3% by weight based on the total weight of the aqueous solution was added dropwise at a rate of 3 mL/min, and the stirring was stopped at the point where the latex composition for dip molding began to aggregate.

In order to quantitatively analyze the chemical stability of the latex composition for dip molding according to Comparative Examples 1 and 1 to 6 of the present invention, a chemical stability index (CSI) expressed as in Equation 1 was calculated. .

[Equation 1]

CSI (%) = coagulation time (min) of the latex composition for dip molding according to Comparative Example 1 or Examples 1 to 6 / coagulation time (min) of the latex composition for dip molding according to Comparative Example 1 (min) * 100

Table 2 below summarizes the CSI of the latex composition for dip molding according to Comparative Example 1 and Examples 1 to 6 of the present invention.

division CSI Comparative Example 1 100 Example 1 119.0 Example 2 118.0 Example 3 117.0 Example 4 122.0 Example 5 121.0 Example 6 120.4 * Unit: CSI(%)

Referring to Table 2, when PVP or PVA is used as an additive, it can be seen that the CSI of the latex composition for dip molding increased by at least 18%, regardless of the fumed silica content.

Experimental Example 2

6 L of calcium nitrate aqueous solution (calcium nitrate) containing 18% by weight of calcium nitrate based on the total weight of the aqueous solution was added to an oven at 60° C. and heated for about 3 hours to bring it to a medium temperature.

A plate-shaped ceramic mold having a size of 17 cm * 17 cm * 0.5 cm in width * length * thickness was immersed in the medium-temperature solution for 1 minute, and then dried at 80° C. for 3 minutes, and the coagulant was used as a plate-shaped ceramic. It was applied to the mold. Subsequently, the ceramic mold of the flat plate coated with the coagulant was immersed in the latex composition for dip molding according to Comparative Examples 1 or 1 to 6 of the present invention for 1 minute, and then dried at 70° C. for 10 minutes, and for 3 minutes. Washed with water.

The washed ceramic mold was dried again at 70° C. for 10 minutes, and then crosslinked at 120° C. for 25 minutes. Thereafter, the crosslinked plate-shaped latex film for dip molding was wound from the ceramic mold to obtain a latex molded article for dip molding in the form of a sheet.

The physical properties of the latex molded article for dip molding were measured and shown in Table 3 below. At this time, the test piece of the latex film for dip molding was manufactured in a dumbbell shape according to ASTM D412.

division The tensile strength 100% modulus 300% modulus 500% modulus Elongation Comparative Example 1 42.4 2.7 5.9 22.7 570 Example 1 47.1 2.7 5.5 19.7 608 Example 2 47.4 2.6 5.1 17.0 617 Example 3 46.9 2.5 4.8 16.2 615 Example 4 53.7 2.6 5.5 21.1 610 Example 5 52.9 2.5 5.0 18.3 614 Example 6 54.7 2.4 4.7 17.2 622 * Unit: tensile strength (MPa), elongation (%) modulus (MPa)
* Measurement method: Using UTM (Universal Testing Machine), a test piece of latex film for dip molding was pulled at an elongation speed of 500 mm/min, and tensile strength, modulus, and elongation at break were measured.

In general, the higher the value of the tensile strength and elongation of the latex molded article, the better the dip quality, and the lower the 300% modulus value, the better the user of the dip molded article can feel.

Referring to Table 3, when manufacturing a latex molded article for dip molding by using PVP and fumed silica at the same time, it can be seen that the tensile strength is improved by 10.6 to 11.79%, and the elongation is improved by 6.6 to 8.2%. . In addition, when manufacturing a latex molded article for dip molding by using PVA and fumed silica at the same time, it can be confirmed that the tensile strength is improved by 24.7-29.0%, and the elongation is improved by 7.0-9.1%.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims to be described later, and all changes or modified forms derived from the meaning and scope of the claims and the concept of equivalents thereof should be construed as being included in the scope of the present invention.

Claims (16)

Including a carboxylic acid-modified nitrile-based copolymer latex, a polyvinylpyrrolidone-based resin and a filler,
The content of the polyvinylpyrrolidone-based resin is 0.1 to 3 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex,
The content of the filler is 0.1 to 5 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex,
The polyvinylpyrrolidone resin is,
One monomer selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate, and combinations of two or more of them is 20 to 80 weight based on the total weight of the polyvinylpyrrolidone resin. Containing %, the latex composition for dip molding. The method of claim 1,
The carboxylic acid-modified nitrile-based copolymer latex,
Based on the total weight of the carboxylic acid-modified nitrile-based copolymer latex,
45 to 80% by weight of a conjugated diene-based monomer;
15 to 45% by weight of ethylenically unsaturated nitrile monomer; And
Ethylene unsaturated acid monomer 1 to 10% by weight; containing, a latex composition for dip molding. The method of claim 2,
The conjugated diene-based monomer is composed of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, isoprene, and combinations of two or more of them. One selected from the group, a latex composition for dip molding. The method of claim 2,
The ethylenically unsaturated nitrile monomer is one selected from the group consisting of acrylonitrile, methacrylonitrile, hummaronitrile, α-chloronitrile, α-cyano ethyl acrylonitrile, and combinations of two or more thereof, dip molding For latex composition. The method of claim 2,
The ethylenically unsaturated acid monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, citraconic anhydride, styrene sulfonic acid, monobutyl fumaric acid, monobutyl maleate, mono-2-hydroxy propyl maleic acid, and these One selected from the group consisting of a combination of two or more of, a latex composition for dip molding. delete delete delete The method of claim 1,
The average particle diameter of the filler is 10 to 200 nm, the latex composition for dip molding. The method of claim 1,
The weight average molecular weight of the polyvinylpyrrolidone-based resin is 5,000 to 50,000 g/mol, a latex composition for dip molding. The method of claim 1,
The filler is one selected from the group consisting of silica, fumed silica, precipitated silica, silica sol, and a combination of two or more of them, a latex composition for dip molding. The method of claim 1,
The dip molding latex composition further comprises one selected from the group consisting of a pigment, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, and a combination of two or more of them. The method of claim 1,
The carboxylic acid-modified nitrile-based copolymer latex further comprises one selected from the group consisting of an emulsifier, a polymerization initiator and a molecular weight control agent, a polymerization terminator, a pH control agent, an antioxidant, an oxygen trapping agent, and a combination of two or more thereof, dip molding For latex composition. (a) emulsion polymerization of a mixture of a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer to obtain a carboxylic acid-modified nitrile-based copolymer latex; And
(b) mixing the product of step (a) with an aqueous polyvinylpyrrolidone resin solution and an aqueous filler solution; and
The mixing amount of the polyvinylpyrrolidone-based resin is 0.1 to 3 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex,
The mixing amount of the filler is 0.1 to 5 parts by weight based on 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex,
The polyvinylpyrrolidone resin is,
One monomer selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate, and combinations of two or more of them is 20 to 80 weight based on the total weight of the polyvinylpyrrolidone resin. % Containing, a method for producing a latex composition for dip molding. A dip molded article obtained by dip molding the latex composition for dip molding according to claim 1. The method of claim 15,
The dip molded article is one selected from the group consisting of medical gloves, agricultural and livestock processing gloves, and industrial gloves.