KR20210043186A - Latex composition for dip-forming, method for preparing the composition and article formed by the composition - Google Patents

Abstract

The present invention relates to a latex composition for dip molding. More particularly, the present invention provides a latex composition for dip molding, which includes nitrile-based copolymer latex comprising a main monomer-derived repeating unit and a lignin-derived portion, wherein the main monomer-derived repeating unit includes a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, a repeating unit derived from a conjugated diene-based monomer, and a repeating unit derived from an oxirane-functional monomer.

Description

Latex composition for dip molding, its manufacturing method, and molded products formed therefrom {LATEX COMPOSITION FOR DIP-FORMING, METHOD FOR PREPARING THE COMPOSITION AND ARTICLE FORMED BY THE COMPOSITION}

The present invention relates to a latex composition for dip molding, and more particularly, to the latex composition for dip molding, a manufacturing method thereof, and a molded article manufactured therefrom.

Conventionally, natural rubber has been mainly used as a raw material for products requiring elasticity such as industrial, medical and food gloves, balloons, and condoms. However, in recent years, natural rubber has been replaced by nitrile rubber instead of natural rubber due to the side effects that cause serious protein allergy to some users. Nitrile-based rubber has high oil resistance, and is particularly widely used in work gloves, medical and food gloves used by users dealing with organic solvents. In addition, a product made from nitrile rubber has a property that is not easily pierced by an injection needle, compared to a product made from natural rubber, and thus has an advantage that is suitable for use by medical personnel handling a sharp scalpel or injection needle.

In addition, in recent years, due to the unstable supply and demand of natural rubber, many glove manufacturing companies are converting natural rubber glove production lines to nitrile rubber glove production lines. It is a trend that the use is continuously increasing.

However, as the use of nitrile gloves increases, the amount of waste generated is also increasing, and the problem of waste disposal is becoming serious. Accordingly, there is a need for biodegradable disposable nitrile gloves that rapidly decompose when buried after using gloves.

KR 2018-0025673 A

The problem to be solved in the present invention is to improve the biodegradability of a dip molded article in order to solve the problems mentioned in the technology behind the present invention.

That is, the present invention is intended to improve the biodegradability of a dip-molded product including a nitrile-based copolymer latex containing lignin when preparing a latex composition for dip molding.

According to an embodiment of the present invention for solving the above problems, the present invention includes a nitrile-based copolymer latex comprising a repeating unit derived from a main monomer and a lignin derived portion, and the repeating unit derived from the main monomer is ethylenically unsaturated nitrile. It provides a latex composition for dip molding comprising a repeating unit derived from a monomer-based, a repeating unit derived from a conjugated diene-based monomer, and a repeating unit derived from an oxirane-functional monomer.

In addition, the present invention comprises a main monomer mixture comprising an ethylenically unsaturated nitrile-based monomer, a conjugated diene-based monomer, and an oxirane-functional monomer; And it provides a method for producing a latex composition for dip molding comprising the step (S10) of preparing a nitrile-based copolymer latex by mixing a lignin-derived compound.

In addition, the present invention provides a dip molded article comprising the layer derived from the latex composition for dip molding.

In the case of manufacturing a dip molded product using the latex composition for dip molding according to the present invention, a rapid biodegradation effect can be expected due to the lignin-derived part included in the dip molded product. There is an effect to solve.

In addition, the present invention includes the repeating unit derived from the oxirane-functional monomer as the repeating unit derived from the main monomer of the nitrile-based copolymer latex, thereby improving the binding strength of the lignin-derived portion in the nitrile-based copolymer latex.

The terms or words used in the description and claims of the present invention should not be construed as being limited to a conventional or dictionary meaning, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention.

In the present invention, the term'monomer-derived repeating unit' may refer to a component, structure, or substance itself derived from a monomer, and refers to a repeating unit formed in the polymer by participating in the polymerization reaction of the introduced monomer during polymerization of the polymer. It can be.

In the present invention, the term'latex' may mean that a polymer or copolymer polymerized by polymerization is dispersed in water, and as a specific example, fine particles of a rubber polymer or rubber copolymer polymerized by emulsion polymerization It may mean that is present in a colloidal state and dispersed in water.

In the present invention, the term'derived layer' may refer to a layer formed from a polymer or a copolymer, and as a specific example, when manufacturing a dip molded article, the polymer or copolymer is attached, fixed, and/or polymerized on a dip mold to form a polymer or It may mean a layer formed from a copolymer.

In the present invention, the term'(meth)acrylate' may mean that both acrylate and methacrylate are possible.

According to an embodiment of the present invention, there is provided a latex composition for dip molding. The dip molding latex composition includes a nitrile-based copolymer latex containing a repeating unit derived from a main monomer and a lignin derived part, and the repeating unit derived from the main monomer is a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, and a repeating derived from a conjugated diene-based monomer. It may include a unit and a repeating unit derived from an oxirane-functional monomer.

According to an embodiment of the present invention, the ethylenically unsaturated nitrile-based monomer forming the repeating unit derived from the ethylenically unsaturated nitrile-based monomer is acrylonitrile, methacrylonitrile, fumaronitrile, α-chloronitrile, and α-cyano. It may be one or more selected from the group consisting of no ethyl acrylonitrile, and specific examples may be acrylonitrile and methacrylonitrile, and a more specific example may be acrylonitrile.

The content of the repeating unit derived from the ethylenically unsaturated nitrile-based monomer may be 10% to 50% by weight, 15% to 45% by weight, or 20% to 40% by weight, based on the total content of the repeating unit derived from the main monomer, , Within this range, a dip-molded article molded from a dip-molding latex composition containing the nitrile-based copolymer latex is flexible, has excellent touch and fit, and has excellent oil resistance and tensile strength.

According to an embodiment of the present invention, the conjugated diene-based monomer forming the repeating unit derived from the conjugated diene-based monomer is 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3 -It may be one or more selected from the group consisting of butadiene, 1,3-pentadiene, and isoprene, and as a specific example, it may be 1,3-butadiene or isoprene, and a more specific example, it may be 1,3-butadiene.

The content of the repeating unit derived from the conjugated diene-based monomer may be 50% by weight to 90% by weight, 55% by weight to 85% by weight, or 60% by weight to 80% by weight, based on the total content of the repeating unit derived from the main monomer. Within the range, the dip-molded article molded from the dip-molding latex composition containing the nitrile-based copolymer latex is flexible, has excellent touch and fit, and has excellent oil resistance and tensile strength.

According to an embodiment of the present invention, the oxirane-functional monomer forming the oxirane-functional repeating unit is glycidyl (meth)acrylate, allyl glycidyl ether, vinyl glycidyl ether, vinyl Cyclohexene oxide, limonene oxide, 2-ethylglycidyl acrylate, 2-ethylglycidyl methacrylate, 2-(n-propyl) glycidyl acrylate, 2-(n-propyl) glycidyl meth Acrylate, 2-(n-butyl) glycidyl acrylate, 2-(n-butyl) glycidyl methacrylate, glycidylmethyl methacrylate, glycidyl acrylate, (3',4' -Epoxyheptyl)-2-ethylacrylate, (3',4'-epoxyheptyl)-2-ethylmethacrylate, (6',7'-epoxyheptyl)acrylate, (6',7'-epoxy Heptyl) methacrylate, allyl-3,4-epoxyheptyl ether, 6,7-epoxyheptyl allyl ether, vinyl-3,4-epoxyheptyl ether, 3,4-epoxyheptyl vinyl ether, 6,7-epoxyheptyl Vinyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3-vinyl cyclohexene oxide, alpha-methyl glycidyl methacrylate and 3,4 -It may be a structural unit derived from an oxirane-functional ethylenically unsaturated monomer comprising at least one selected from the group consisting of -epoxycyclohexylmethyl(meth)acrylate. As a specific example, the oxirane-functional monomer may be glycidyl methacrylate.

The content of the oxirane-functional repeating unit may be 0.1 wt% to 15 wt%, 0.5 wt% to 9 wt%, or 0.5 wt% to 5 wt%, based on the total content of the repeating unit derived from the main monomer, Within this range, the bonding strength of the lignin-derived portion in the nitrile-based copolymer latex may be improved.

In addition, according to an embodiment of the present invention, in the nitrile-based copolymer latex, the repeating unit derived from the main monomer may further include a repeating unit derived from an ethylenically unsaturated acid monomer to form a carboxylic acid-modified nitrile-based copolymer. have.

The ethylenically unsaturated acid monomer forming the repeating unit derived from the ethylenically unsaturated acid monomer may be an ethylenically unsaturated monomer containing an acidic group such as a carboxyl group, a sulfonic acid group, and an acid anhydride group, specific examples of acrylic acid, methacrylic acid, itaconic acid, Ethylenically unsaturated acid monomers such as maleic acid and fumaric acid; Polycarboxylic anhydrides such as maleic anhydride and citraconic anhydride; Ethylenically unsaturated sulfonic acid monomers such as styrene sulfonic acid; It may be one or more selected from the group consisting of ethylenically unsaturated polycarboxylic acid partial ester monomers such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleic acid, and more specific examples of acrylic acid and methacrylic acid , Itaconic acid, maleic acid, and may be one or more selected from the group consisting of fumaric acid, and a more specific example may be methacrylic acid. The ethylenically unsaturated acid monomer may be used in the form of a salt such as an alkali metal salt or an ammonium salt during polymerization.

The content of the repeating unit derived from the ethylenically unsaturated acid monomer may be 0.1% to 15% by weight, 0.5% to 9% by weight, or 1% to 8% by weight, based on the total content of the repeating unit derived from the main monomer, Within this range, the dip-molded article molded from the latex composition for dip molding including the carboxylic acid-modified nitrile-based copolymer latex is flexible, has excellent fit, and has excellent resistance and tensile strength.

According to an embodiment of the present invention, the repeating unit derived from the main monomer may optionally further include a repeating unit derived from an ethylenically unsaturated monomer.

The ethylenically unsaturated monomer forming the repeating unit derived from the ethylenically unsaturated monomer is a vinyl aromatic monomer selected from the group consisting of styrene, aryl styrene, and vinyl naphthalene; Fluoroalkyl vinyl ethers such as fluoro ethyl vinyl ether; (Meth)acrylamide, N-methylol (meth)acrylamide, N,N-dimethylol (meth)acrylamide, N-methoxy methyl (meth)acrylamide, and N-propoxy methyl (meth)acrylamide Ethylenically unsaturated amide monomers selected from the group consisting of; Non-conjugated diene monomers such as vinyl pyridine, vinyl norbornene, dicyclopentadiene, and 1,4-hexadiene; Methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, dibutyl maleate, Dibutyl fumarate, diethyl maleate, methoxymethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxyethyl (meth)acrylate, cyanomethyl (meth)acrylate, 2-cyano (meth)acrylate Ethyl, (meth)acrylic acid 1-cyanopropyl, (meth)acrylic acid 2-ethyl-6-cyanohexyl, (meth)acrylic acid 3-cyanopropyl, (meth)acrylic acid hydroxyethyl, (meth)acrylic acid hydroxy It may be one or more selected from the group consisting of ethylenically unsaturated carboxylic acid ester monomers selected from the group consisting of propyl, glycidyl (meth)acrylate, and dimethylamino ethyl (meth)acrylate.

The content of the repeating unit derived from the ethylenically unsaturated monomer may be within 25% by weight, 0.01 to 25% by weight, or 0.01 to 15% by weight, based on the total content of the repeating unit derived from the main monomer, and within this range, the nitrile-based copolymer A dip-molded product molded from a dip-molding latex composition containing latex has excellent tactile and fit, and excellent tensile strength.

According to an embodiment of the present invention, the lignin-derived portion may be derived from lignin or a lignin by-product. The lignin may be used by purchasing a commercially available product, or may be extracted and used by a conventional method. For example, the lignin may be a lignosulfonate, an organic solvent 　 lignin, or a basic 　 lignin, but is not particularly limited as long as it is conventionally used 　 lignin. As an example of the lignin by-product, it may include a lignin by-product produced as a by-product of a process of producing palm oil (crude palm oil).

The lignin may be 0.1 to 35 parts by weight, 0.1 to 20 parts by weight, or 0.1 to 5 parts by weight based on the total 100 parts by weight of the repeating unit derived from the main monomer. Within this range, the dip-molded article molded from the dip-molding latex composition containing the nitrile-based copolymer has the effect of rapidly becoming microparticles by heat and biodegradation.

In particular, in the latex composition for dip molding, the content of the lignin-derived part is 0.1 to 20 parts by weight based on the total 100 parts by weight of the repeating unit derived from the main monomer, and the content of the repeating unit derived from the oxirane-functional monomer is In the case of 0.1% to 5% by weight based on the total content of the repeating unit derived from the main monomer, the bonding strength of the lignin-derived portion in the nitrile-based copolymer latex is excellent, and the dip-molded product molded from the latex composition for dip molding due to the lignin-derived portion thus formed It has the effect of rapidly becoming fine particles by heat and biodegradation.

In addition, according to an embodiment of the present invention, the latex composition for dip molding may further include additives such as a vulcanizing agent, an ionic crosslinking agent, a pigment, a vulcanization catalyst, a filler, and a pH adjusting agent, if necessary.

In addition, according to an embodiment of the present invention, the latex composition for dip molding, for example, has a solid content (concentration) of 10% to 40% by weight, 15% to 35% by weight, or 18% to 33% by weight It may be, and within this range, the efficiency of the latex transport is excellent, and there is an effect of excellent storage stability by preventing an increase in the viscosity of the latex.

As another example, the dip molding latex composition may have a pH of 8 to 12, 9 to 11, or 9.3 to 11, and has excellent processability and productivity when manufacturing a dip molded article within this range. The pH of the latex composition for dip molding may be adjusted by the introduction of the aforementioned pH adjusting agent. The pH adjusting agent may be, for example, an aqueous potassium hydroxide solution having a concentration of 1% to 5% by weight, or aqueous ammonia having a concentration of 1% to 5% by weight.

In addition, according to an embodiment of the present invention, the glass transition temperature of the nitrile-based copolymer latex in the dip molding latex composition is -50 °C to -15 °C, -47 °C to -15 °C, or -45 °C to -20 °C. It may be, and within the above range, the tensile strength of the molded article dip-molded from the dip-molding latex composition containing the nitrile-based copolymer latex prevents deterioration of tensile properties, such as cracking, while preventing the occurrence of cracks, and has an excellent fit due to low stickiness. have. The glass transition temperature may be measured using a differential scanning calorimetry.

In addition, according to an embodiment of the present invention, the average particle diameter of the nitrile-based copolymer latex particles in the dip molding latex composition may be 100 nm to 500 nm, 100 nm to 200 nm, or 120 nm to 150 nm. Within the above range, the viscosity of the nitrile-based copolymer latex is not increased, so that the nitrile-based copolymer latex can be manufactured at a high concentration, and the tensile properties such as tensile strength of the molded article dip-molded from the dip-molding latex composition containing the same are not increased. It has an excellent effect. In addition, the film formation rate is controlled to an appropriate level within the above range, so that synergy properties are excellent. The average particle diameter may be measured using a laser scattering analyzer (Nicomp).

According to the present invention, a method for preparing a latex composition for dip molding is provided. The dip molding latex composition manufacturing method includes a main monomer mixture comprising an ethylenically unsaturated nitrile-based monomer, a conjugated diene-based monomer, and an oxirane-functional monomer; And mixing the lignin-derived compound to prepare a nitrile-based copolymer latex (S10).

That is, the method for preparing the latex composition for dip molding according to the present invention is a mixture of a lignin-derived compound in a main monomer mixture including an ethylenically unsaturated nitrile-based monomer, a conjugated diene-based monomer, and an oxirane-functional monomer, and polymerized to obtain a nitrile-based compound. It may include the step of preparing a latex composition for dip molding comprising a copolymer latex.

According to an embodiment of the present invention, the polymerization of the nitrile-based copolymer latex may be carried out by emulsion polymerization. The emulsion polymerization may be carried out by polymerization of the main monomer mixture and the lignin-derived compound, and each monomer and lignin-derived compound included in the main monomer mixture may be added in the type and amount of the aforementioned monomers, and batch It can be input, continuous input, or divided input.

In addition, according to an embodiment of the present invention, the polymerization of the nitrile-based copolymer latex may be carried out in the presence of a separate emulsifier, a polymerization initiator, an activator, and a molecular weight modifier.

The emulsifier is added to impart stability to the latex during and after the polymerization reaction, and various types of emulsifiers may be used.

The emulsifier may be, for example, one or more selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants, and specific examples thereof include alkylbenzene sulfonates, aliphatic sulfonates, higher alcohol sulfuric acid It may be one or more anionic surfactants selected from the group consisting of ester salts, α-olefin sulfonates, and alkyl ether sulfate ester salts.

The emulsifier may be added in an amount of 0.3 parts by weight to 10 parts by weight, 0.8 parts by weight to 8 parts by weight, or 1.5 parts by weight to 6 parts by weight based on 100 parts by weight of the total content of the main monomer mixture, and the polymerization stability is excellent within this range. And, there is an effect that the production of the molded article is easy because the amount of foaming is small.

In addition, when the polymerization of the nitrile-based copolymer latex is carried out including a polymerization initiator, a radical initiator may be used. For example, the radical initiator may include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-mentanehydro peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide Organic peroxides such as oxide, 3,5,5-trimethylhexanol peroxide, and t-butyl peroxy iso butylate; And nitrogen compounds such as azobis isobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and methyl azobis isobutylate. The polymerization initiator may be used alone or in combination of two or more. As a specific example, an inorganic peroxide may be used as the radical initiator, and as a more specific example, a persulfate may be used as the radical initiator.

The polymerization initiator may be added in an amount of 0.01 parts by weight to 2 parts by weight or 0.02 parts by weight to 1.5 parts by weight based on 100 parts by weight of the total content of the main monomer mixture, and there is an effect of maintaining the polymerization rate at an appropriate level within this range. .

In addition, when the polymerization of the nitrile-based copolymer latex is carried out including an activator, the activator is sodium formaldehyde, sulfoxylate, sodium ethylenediamine terraacetate, ferrous sulfate, dextrose, pyrrolic acid. It may be one or more selected from the group consisting of sodium and sodium sulfite.

The activator may be added in an amount of 0.01 parts by weight to 2.0 parts by weight, 0.02 parts by weight to 1.5 parts by weight, or 0.05 parts by weight to 1.0 parts by weight based on 100 parts by weight of the total content of the main monomer mixture, and the polymerization rate within this range There is an effect that can be maintained at an appropriate level.

In addition, when the polymerization of the nitrile-based copolymer latex is carried out including a molecular weight control agent, the molecular weight control agent is, for example, α-methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, octyl mer Mercaptans such as captan; Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, and methylene bromide; And sulfur-containing compounds such as tetraethylthiuram disulfide, dipentamethylthiuram disulfide, and diisopropylxanthogen disulfide. These molecular weight modifiers may be used alone or in combination of two or more. As a specific example, the molecular weight control agent may use mercaptans, and as a more specific example, the molecular weight control agent may use t-dodecyl mercaptan.

The molecular weight modifier may be added in an amount of 0.1 parts by weight to 1.5 parts by weight or 0.2 parts by weight to 1 part by weight based on 100 parts by weight of the total content of the main monomer mixture, and has excellent polymerization stability within this range, and when manufacturing a molded article after polymerization, It has an excellent effect on the physical properties of the molded product.

In addition, according to an embodiment of the present invention, the polymerization of the nitrile-based copolymer latex may be carried out in water as a medium, for example, deionized water, and in order to ensure ease of polymerization, a chelating agent, a dispersant, and a pH adjuster as necessary. , Additives such as a deoxidant, a particle size control agent, an anti-aging agent, an oxygen scavenger, and the like may be further included.

According to an embodiment of the present invention, the emulsifier, polymerization initiator, molecular weight modifier, additive, and the like may be added collectively or dividedly into a polymerization reactor like the monomer mixture, and may be continuously added at each input.

In addition, according to an embodiment of the present invention, the polymerization of the nitrile-based copolymer latex may be carried out at a polymerization temperature of 10°C to 90°C, 20°C to 80°C, or 25°C to 75°C, within this range. The latex stability has an excellent effect.

On the other hand, according to an embodiment of the present invention, the dip molding latex composition manufacturing method may terminate the polymerization reaction to obtain a nitrile-based copolymer latex. Termination of the polymerization reaction of the carboxylic acid-modified nitrile-based copolymer latex may be carried out at a point in which the polymerization conversion rate is 90% or more, 91% or more, or 92% to 99.9%, and addition of a polymerization terminator, a pH adjuster, and an antioxidant. Can be carried out by In addition, the method for preparing the latex composition may further include a step of removing unreacted monomers by a deodorizing concentration process after the reaction is completed.

According to an embodiment of the present invention, after the step (S10) of preparing a nitrile-based copolymer latex, a step (S20) of preparing a latex composition including the nitrile-based copolymer latex may be further included.

According to an embodiment of the present invention, in the step (S20), in addition to the nitrile-based copolymer latex, at least one selected from the group consisting of a vulcanizing agent, a vulcanization accelerator, and zinc oxide may be further included.

When the polymerization in the step of preparing the latex composition is carried out including a vulcanizing agent, the vulcanizing agent may include, for example, powdered sulfur, precipitated sulfur, colloidal sulfur, surface treated sulfur, insoluble sulfur, and the like. The content of the vulcanizing agent may be 0.1 parts by weight to 10 parts by weight, 0.3 parts by weight, or 5 parts by weight based on 100 parts by weight of the solid content of the nitrile-based copolymer latex.

When the polymerization of the step of preparing the latex composition is carried out including a vulcanization accelerator, the vulcanization accelerator is, for example, 2-mercaptobenzothiazole (MBT), 2,2-dithiobisbenzota Azol-2-sulfenamide (2,2-Dithiobisbezothiozolo-2-sulfenamide, MBTS), N-cyclohexylbenzothiazole-2-sulfenamide (N-Cyclehexylbenzothiazole-2-sulfenamide, CBS), 2-morpholinothio Benzothiazole (2-Morpholinothiobenzothiazole (MBS)), tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), zinc diethyldithiocarbamate (Zinc diethyldithiocarbamate) , Zinc dibutyldithiocarbamate (ZDBC), diphenylguanidine (DPG), di-olso-tolyguanidine (Di-o-tolyguanidine, DOTG), and the like. The vulcanization accelerator may be used alone or in combination of two or more. The content of the vulcanization accelerator may be 0.1 parts by weight to 10 parts by weight or 0.3 parts by weight to 5 parts by weight based on 100 parts by weight of the solid content of the nitrile-based copolymer latex.

When the polymerization in the step of preparing the latex composition is carried out including zinc oxide, the content of zinc oxide is 0.1 to 5 parts by weight or 0.5 to 2 parts by weight based on 100 parts by weight of the nitrile-based copolymer latex solid content. It may be parts by weight. At this time, the zinc oxide may be added in a mixed form, and the zinc oxide solution may include zinc oxide, ammonium carbonate, aqueous ammonia and water, and the content of zinc oxide in the zinc oxide solution is 1 weight. % To 20% by weight, or 1% to 15% by weight, within this range, the crosslinking ability is excellent, the latex stability is excellent, and the resulting dip molded article has excellent tensile strength and flexibility.

In the step of preparing the latex composition, a pigment, a thickener, a chelating agent, a dispersing agent, a pH adjusting agent, a deoxygenating agent, a particle size adjusting agent, an anti-aging agent, an oxygen scavenger, and the like may be used as necessary.

The polymerization temperature in the step of preparing the latex composition may be, for example, 10°C to 90°C or 25°C to 75°C.

According to the present invention, a molded article comprising a layer derived from the latex composition for dip molding is provided. The molded article may be a dip molded article prepared by dip molding the latex composition for dip molding, and may be a molded article including a layer derived from the dip molding latex composition formed from the latex composition for dip molding by dip molding. The molded article manufacturing method for molding the molded article may include immersing the latex composition for dip molding by a direct immersion method, an anode adhesion immersion method, a Teague adhesion immersion method, etc. It can be carried out by an adhesion immersion method, and in this case, there is an advantage in that a dip-molded article having a uniform thickness can be obtained.

As a specific example, the method of manufacturing a dip molded article includes the steps of attaching a coagulant to a dip mold (S100); Immersing the latex composition for dip molding in the dip molding mold to which the coagulant is attached to form a layer derived from the latex composition for dip molding, that is, a dip molding layer (S200); And heating the dip molding layer to crosslink the latex composition for dip molding (S300).

The step (S100) is a step of attaching a coagulant to the surface of the dip molding mold by immersing the dip molding mold in a coagulant solution to form a coagulant in the dip molding mold. As a dissolved solution, the content of the coagulant in the coagulant solution may be 5% to 50% by weight, 7% to 45% by weight, or 10% to 40% by weight based on the total content of the coagulant solution.

The coagulant may be, for example, a metal halide such as barium chloride, calcium chloride, magnesium chloride, zinc chloride, and aluminum chloride; Nitrates such as barium nitrate, calcium nitrate and zinc nitrate; Acetates such as barium acetate, calcium acetate, and zinc acetate; And it may be one or more selected from the group consisting of sulfates such as calcium sulfate, magnesium sulfate, and aluminum sulfate, and a specific example may be calcium chloride or calcium nitrate.

In the step (S100), in order to attach the coagulant to the dip molding die, the dip molding die is immersed in the coagulant solution for 1 minute or more, 1 minute to 10 minutes, or 1 minute to 5 minutes, and after taking out, 70 to 150°C, It may further include drying at 70 ℃ to 130 ℃ or 70 ℃ to 100 ℃.

In addition, the step (S200) may be a step of immersing a dip molding mold to which a coagulant is attached to form a dip molding layer in the latex composition for dip molding according to the present invention, and taking it out to form a dip molding layer on the dip molding mold. have.

As a specific example, the step (S200) may be performed by repeating at least 2 times, 2 times to 12 times, or 2 to 10 times as necessary, in this case, the dip molded article by further strengthening the layer derived from the latex composition for dip molding It has excellent mechanical properties such as tensile properties and durability.

In addition, in the step (S200), in order to form a dip molding layer on the dip molding mold, a dip molding mold attached with a coagulant was added to the latex composition for dip molding for 1 minute or more, 1 minute to 10 minutes, or 1 minute to 5 minutes. It may further include a step of immersing for, and drying at 70 to 150° C., 70 to 130° C., or 70 to 100° C. after taking out.

In addition, the step (S300) may be a step of evaporating a liquid component by heating a dip molding layer formed on a dip molding mold to obtain a dip molding product, and crosslinking the latex composition for dip molding to proceed with curing.

Thereafter, the crosslinked dip molding layer may be peeled off from the dip molding mold by heat treatment to obtain a dip molded article.

According to an embodiment of the present invention, the molded article may be a glove such as a surgical glove, an examination glove, an industrial glove and a household glove, a condom, a catheter, or a health care product.

Hereinafter, the present invention will be described in more detail by examples. However, the following examples are intended to illustrate the present invention, and that various changes and modifications can be made within the scope of the present invention and the scope of the technical idea are obvious to those skilled in the art, and the scope of the present invention is not limited thereto.

Example

Example 1

<Production of carboxylic acid-modified nitrile-based copolymer latex>

A 10L high-pressure reactor equipped with a stirrer, a thermometer, a cooler, an inlet of nitrogen gas and an inlet to continuously input monomers, emulsifiers, and polymerization initiators was replaced with nitrogen, and then 25% by weight of acrylonitrile in the reactor, 1,3 -A main monomer mixture composed of 69% by weight of butadiene, 5% by weight of methacrylic acid and 1% by weight of glycidyl methacrylate, and 1 part by weight of lignin and 2.5 parts by weight of sodium dodecylbenzene sulfonate based on 100 parts by weight of the main monomer mixture Parts, 0.5 parts by weight of t-dodecyl mercaptan and 140 parts by weight of water were added and the temperature was raised to 40°C. After the temperature of the reactor reached 40 ℃, polymerization was carried out by adding 0.25 parts by weight of potassium persulfate as a polymerization initiator, and when the polymerization conversion rate was 95%, 0.1 parts by weight of sodium dimethyl dithiocarbamate was added to stop the polymerization. Made it. Subsequently, the unreacted monomer was removed through a deodorization process, and aqueous ammonia, an antioxidant, and an antifoaming agent were added to obtain a carboxylic acid-modified nitrile-based copolymer latex having a solid content of 45% by weight and a pH of 8.5. At this time, the glass transition temperature of the prepared carboxylic acid-modified nitrile-based copolymer latex was -30°C, and the average particle diameter of the carboxylic acid-modified nitrile-based copolymer in the latex was 120 nm.

<Preparation of latex composition for dip molding>

To 100 parts by weight of the obtained carboxylic acid-modified nitrile-based copolymer latex (based on solid content), 2 parts by weight of a potassium hydroxide solution having a concentration of 1.25% by weight, 1.2 parts by weight of sulfur powder, 0.7 parts by weight of di-n-butyldithiocarbamate zinc Part and second distilled water were added to obtain a latex composition for dip molding having a solid content concentration of 18% by weight and a pH of 10.0.

<Manufacture of dip molded products>

A coagulant solution was prepared by mixing 18 parts by weight of calcium nitrate, 81.5 parts by weight of water, and 0.5 parts by weight of a wetting agent (Teric 320, Huntsman Corporation, Australia). The hand-shaped ceramic dip molding mold was immersed in the prepared coagulant solution for 3 minutes, taken out, and dried at 80° C. for 4 minutes to apply the coagulant to the hand-shaped dip molding mold.

Thereafter, the dip molding mold coated with the coagulant was immersed in the obtained latex composition for dip molding for 3 minutes, taken out, and dried at 80° C. for 2 minutes. Subsequently, the hand-shaped dip molding mold was immersed in the monomer solution for 3 minutes, taken out and dried at 40° C. for 10 minutes, and the dip molded product was peeled off from the hand-shaped dip molding mold to obtain a glove-shaped dip molded product.

Example 2

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 5 parts by weight of lignin was used instead of 1 part by weight of lignin.

Example 3

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 10 parts by weight of lignin was used instead of 1 part by weight of lignin.

Example 4

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 15 parts by weight of lignin was used instead of 1 part by weight of lignin.

Example 5

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 20 parts by weight of lignin was used instead of 1 part by weight of lignin.

Comparative example

Comparative Example 1

In Example 1, when preparing the latex composition for dip molding, when preparing the latex composition for dip molding, acrylonitrile 25% by weight, 1,3-butadiene 70% by weight without glycidyl methacrylate as the main monomer mixture , Except that the main monomer mixture containing 5% by weight of methacrylic acid was used, and lignin was not used, it was carried out in the same manner as in Example 1.

Comparative Example 2

In Example 1, the preparation of the latex composition for dip molding was carried out in the same manner as in Example 1, except that lignin was not used.

Comparative Example 3

In Example 1, when preparing the latex composition for dip molding, 25% by weight of acrylonitrile, 70% by weight of 1,3-butadiene, and 5% by weight of methacrylic acid were used without using glycidyl methacrylate as the main monomer mixture. It was carried out in the same manner as in Example 1, except that the containing main monomer mixture was used.

Comparative Example 4

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 1 part by weight of starch was used instead of 1 part by weight of lignin.

Comparative Example 5

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 5 parts by weight of starch was used instead of 1 part by weight of lignin.

Comparative Example 6

In Example 1, when preparing the latex composition for dip molding, it was carried out in the same manner as in Example 1, except that 10 parts by weight of starch was used instead of 1 part by weight of lignin.

Experimental example

Experimental Example 1

In order to compare the physical properties of the dip-molded products prepared in Examples 1 to 5 and Comparative Examples 1 to 6, the thickness, tensile strength, elongation, stress at 300% and 500% elongation, breaking strength and durability were measured under the following conditions. It is shown in Table 1 and Table 2 below.

* Thickness (mm): 　 thickness was measured using a digital 　 thickness 　 measuring device.

* Tensile stress (MPa), elongation (%), stress at 300% elongation (300% Modulus, MPa) and stress at 500% elongation (500% Modulus, MPa): According to EN 455-2 According to this, a dumbbell-shaped specimen was produced. Subsequently, the specimen was pulled at an elongation speed of 500 mm/min, and the stress at the elongation rates of 300% and 500%, and the tensile strength at break (Force at break, N) were measured. In addition, each physical property was measured for aging at 70° C. for 4 hours and aging at 120° C. for 4 hours in a convection oven.

* Durability (times): After preparing a solution for measuring the durability of a dip-molded product at 25° C. consisting of 16 parts by weight of sodium chloride, 16 parts by weight of lactic acid, 3.2 parts by weight of urea, and 64.8 parts by weight of water, each example and comparison in a durability measuring device After inserting the dip-molded product specimen obtained in the example, the number of times to break was measured while increasing the specimen to 2.6 times the initial length (maximum 2.6 times when stretching, and at least 1 times when reducing). At this time, the high number of times is judged to be excellent in durability.

Example One 2 3 4 5 Thickness mm 0.051 0.05 0.049 0.048 0.046 Force at Break N 5.54 5.39 4.87 5.32 4.81 Tensile Stress Mpa 34.24 33.71 30.03 28.29 24.3 Elongation % 482.1 466.57 437.5 551.2 490.11 300% Modulus Mpa 11.67 11.04 9.32 6.22 5.78 500% Modulus Mpa 33.55 33.93 29.16 16.93 16.2 Durability (260%) Cycle 336 298 319 329 290 Force at Break Aging
(70℃, 4h) 6.4 6.4 5.2 5.75 5.06 Force at Break Aging
(120℃, 4h) 5.1 3.8 2.9 3.81 3.36 Durability (260%) Aging
(70℃, 4h) 349 317 322 330 326 Durability (260%) Aging(120℃, 4h) 281 245 253 207 191

Comparative example One 2 3 4 5 6 Thickness mm 0.056 0.055 0.55 0.056 0.051 0.053 Force at Break N 5.74 5.8 5.66 5.53 5.15 4.96 Tensile Stress Mpa 34.1 35.5 34.1 34.23 33.02 31.29 Elongation % 596.23 588.2 592.1 588.1 579.24 583.17 300% Modulus Mpa 6.14 6.25 6.46 6.2 6.6 6.92 500% Modulus Mpa 17.13 17.23 17.03 17.41 17.53 18.48 Durability (260%) Cycle 357 337 345 362 269 174 Force at Break Aging
(70℃, 4h) 6.41 6.47 5.82 4.24 4.76 3.22 Force at Break Aging
(120℃, 4h) 4.52 4.78 4.38 3.53 2.29 1.83 Durability (260%) Aging
(70℃, 4h) 426 513 341 235 128 81 Durability (260%) Aging(120℃, 4h) 372 366 315 45 39 17

Referring to Tables 1 and 2, it can be seen that Examples 1 to 5 according to the present invention contain lignin and exhibit the same level of physical properties as compared to Comparative Example 1 that does not contain lignin.

In addition, Examples 1 to 5 containing lignin exhibited a decrease in physical properties due to heat, and in particular, as the content of lignin increased, the physical properties decreased due to heat. In comparison, it can be seen that Comparative Example 1 that does not contain lignin maintains physical properties. Through this, it can be seen that biodegradation of the dip molded article according to the present invention easily occurs through heat, but in Comparative Example 1, biodegradation will be difficult.

In addition, looking at Comparative Examples 2 and 3 in which either of lignin and glycidyl methacrylate was not used, physical property degradation due to heat hardly appeared, and through this, due to glycidyl methacrylate, lignin was repeated from the main monomer. It was found that the bonding strength within the unit increased, and when either one of the two was used alone, the effect of improving the biodegradability could not be realized.

In addition, Examples 1 to 5 including lignin showed physical properties equivalent to those of Comparative Example 1, but Comparative Examples 4 to 6 including starch instead of lignin showed reduced physical properties.

Experimental Example 2

In order to compare the biodegradability of the dip-molded products prepared in Example 2, Example 3, and Comparative Example 1, a mixture containing 10 g of natural soil in 1 L of ionized water was impregnated at 34° C. for 72 hours, and then the thickness, tensile strength, and elongation rate , Stress at 300% and 500% elongation, breaking strength, and durability were measured under the following conditions, and are shown in Table 3 below.

Example 2 Example 3 Comparative Example 1 Thickn　ess mm 0.04 0.042 0.056 Fcrce　at　Break N 3.41 1.26 5.74 Tensile　Stress Mpa 15.19 8.46 34.1 Elogation % 364.11 217.35 596.23 300%　Modulus Mpa 2.46 2.07 6.14 500%　Modulus Mpa 7.71 6.25 17.13 Durability (260%) Cycle 20 8 357

As shown in Table 3, it was confirmed that the dip molded product containing lignin had a decomposition action by microorganisms contained in natural soil.

Claims (10)

It includes a nitrile-based copolymer latex comprising a repeating unit derived from a main monomer and a lignin-derived portion,
The repeating unit derived from the main monomer includes a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, a repeating unit derived from a conjugated diene-based monomer, and a repeating unit derived from an oxirane-functional monomer. The method of claim 1,
The repeating unit derived from the main monomer is a nitrile-based copolymer latex further comprising a repeating unit derived from an ethylenically unsaturated acid monomer. The method of claim 1,
The lignin-derived part is a latex composition for dip molding that is derived from lignin or lignin by-products. The method of claim 1,
The content of the lignin-derived part is 0.1 parts by weight to 35 parts by weight based on the total 100 parts by weight of the repeating unit derived from the main monomer. The method of claim 1,
The content of the repeating unit derived from the oxirane-functional monomer is 0.1% to 15% by weight based on the total content of the repeating unit derived from the main monomer. The method of claim 1,
The oxirane-functional monomer is glycidyl (meth)acrylate, allyl glycidyl ether, vinyl glycidyl ether, vinyl cyclohexene oxide, limonene oxide, 2-ethylglycidyl acrylate, 2-ethylgly Cidyl methacrylate, 2-(n-propyl) glycidyl acrylate, 2-(n-propyl) glycidyl methacrylate, 2-(n-butyl) glycidyl acrylate, 2-(n -Butyl) glycidyl methacrylate, glycidylmethyl methacrylate, glycidyl acrylate, (3',4'-epoxyheptyl)-2-ethylacrylate, (3',4'-epoxyheptyl )-2-ethylmethacrylate, (6',7'-epoxyheptyl)acrylate, (6',7'-epoxyheptyl)methacrylate, allyl-3,4-epoxyheptyl ether, 6,7- Epoxyheptyl allyl ether, vinyl-3,4-epoxyheptyl ether, 3,4-epoxyheptyl vinyl ether, 6,7-epoxyheptyl vinyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether , p-vinylbenzyl glycidyl ether, 3-vinyl cyclohexene oxide, alpha-methyl glycidyl methacrylate, and 3,4-epoxycyclohexylmethyl (meth) acrylate. The dip molding latex composition. The method of claim 1,
The content of the lignin-derived part is 0.1 parts by weight to 20 parts by weight based on the total 100 parts by weight of the repeating unit derived from the main monomer,
The content of the repeating unit derived from the oxirane-functional monomer is 0.1% to 5% by weight based on the total content of the repeating unit derived from the main monomer. A main monomer mixture comprising an ethylenically unsaturated nitrile-based monomer, a conjugated diene-based monomer, and an oxirane-functional monomer; And mixing the lignin-derived compound to prepare a nitrile-based copolymer latex (S10). The method of claim 8,
The method of manufacturing a latex composition for dip molding wherein the main monomer mixture further comprises an ethylenically unsaturated acid monomer. A dip-molded article comprising a layer derived from the latex composition for dip molding according to any one of claims 1 to 7.