KR20210039947A - Carboxylic acid modified nitrile based copolymer latex, method for preparing the copolymer latex and article formed by the copolymer latex - Google Patents

Abstract

The present invention relates to carboxylic acid-modified nitrile-based copolymer latex. More particularly, the present invention provides carboxylic acid-modified nitrile-based copolymer latex, comprising a carboxylic acid-modified nitrile-based copolymer including a repeating unit derived from a conjugated diene-based monomer, a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, and a repeating unit derived from an ethylenically unsaturated acid monomer, and sodium alkane sulfonate, wherein the content of the sodium alkane sulfonate included is 0.7 to 4.8 parts by weight based on 100 parts by weight of the total of the carboxylic acid-modified nitrile-based copolymer.

Description

Carboxylic acid-modified nitrile-based copolymer latex, its manufacturing method, and molded products formed therefrom {CARBOXYLIC ACID MODIFIED NITRILE BASED COPOLYMER LATEX, METHOD FOR PREPARING THE COPOLYMER LATEX AND ARTICLE FORMED BY THE COPOLYMER LATEX}

The present invention relates to a carboxylic acid-modified nitrile-based copolymer latex, and more particularly, to the carboxylic acid-modified nitrile-based copolymer latex, a method for producing the same, and a molded article manufactured therefrom.

As the demand for gloves used for medical inspection, airport and parcel inspection around the world is increasing, problems with polyvinyl chloride (PVC) and natural rubber, the main raw materials used for these purposes, have arisen. The market for phosphorus acrylonitrile-butadiene-based latex is growing significantly.

PVC gloves are manufactured by mixing PVC plastisol and DOP as a plasticizer. Due to environmental issues, production and demand are gradually decreasing, and new substitutes are required. Its use is largely limited, especially in hospitals and restaurants, and its use has been discontinued.

When manufacturing gloves using acrylonitrile-butadiene-based latex, the current market is expanding rapidly because it can solve the environmental problems and skin allergy problems caused by the above ingredients. The manufacturing process speeds up, and the manufacture of thin, lightweight gloves is becoming more common. However, in the case of manufacturing a thin, lightweight glove, there is a problem that the glove strength is lowered, and thus the demand for a latex capable of expressing a higher strength is increasing.

In addition, as environmental regulations are strengthened around the world, regulations are being strengthened to continuously reduce the content of nonvolatile residues (NVRs) in gloves.

KR 2019-0073694 A

The problem to be solved in the present invention is, in order to solve the problems mentioned in the technology behind the background of the present invention, when dip molding using a latex composition for dip molding containing a carboxylic acid-modified nitrile-based copolymer latex, workability It is to minimize the defect rate while maintaining the physical properties of the dip-molded product at a level equal to or higher than that of the prior art.

That is, the present invention is a latex composition for dip molding comprising the carboxylic acid-modified nitrile-based copolymer latex by using a sodium alkane sulfonate-based emulsifier and reducing the amount of the emulsifier when preparing a carboxylic acid-modified nitrile-based copolymer latex. It is an object of the present invention to provide a carboxylic acid-modified nitrile-based copolymer latex having significantly less defects in the dip molding and reducing nonvolatile residual substances, a method for producing the same, and a dip molded product including the same.

According to an embodiment of the present invention for solving the above problems, the present invention is a carboxylic acid comprising a repeating unit derived from a conjugated diene monomer, a repeating unit derived from an ethylenically unsaturated nitrile monomer, and a repeating unit derived from an ethylenically unsaturated acid monomer. Including a modified nitrile-based copolymer and sodium alkane sulfonate, the content of the sodium alkane sulfonate, based on the total 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer, carboxylic acid contained in an amount of 0.7 parts by weight to 4.8 parts by weight It provides a modified nitrile-based copolymer latex.

In addition, the present invention is a monomer mixture containing a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer; And a step (S10) of preparing a carboxylic acid-modified nitrile-based copolymer latex by mixing sodium alkane sulfonate, wherein the step (S10) includes sodium alkane sulfonate based on 100 parts by weight of the total monomer mixture, 0.7 It provides a method for producing a carboxylic acid-modified nitrile-based copolymer latex that is mixed in parts by weight to 4.8 parts by weight.

In addition, the present invention provides a latex composition for dip molding comprising the carboxylic acid-modified nitrile-based copolymer latex.

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

The carboxylic acid-modified nitrile-based copolymer latex according to the present invention includes sodium alkane sulfonate having 13 to 17 carbon atoms in a linear structure, so that an emulsifier can be used in a small amount when preparing the latex. In the molded article of the latex composition for dip molding including the modified nitrile-based copolymer latex, it is possible to reduce nonvolatile residual substances.

In addition, when the latex is manufactured, even if an emulsifier is used in a small amount, it is possible to prevent a problem of lowering productivity, such as an increase in aggregates or adhering of a coagulum to the reactor, and to manufacture a dip-molded article having excellent tensile strength.

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'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'alkyl' refers to a straight-chain saturated monovalent hydrocarbon of carbon atoms, such as methyl, ethyl, propyl, 2-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl, dodecyl, etc. It may be, and it may mean to include not only unsubstituted ones but also those substituted by a substituent.

According to an embodiment of the present invention, a carboxylic acid-modified nitrile-based copolymer latex is provided. The carboxylic acid-modified nitrile-based copolymer latex is a carboxylic acid-modified nitrile-based copolymer comprising a repeating unit derived from a conjugated diene-based monomer, a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, and a repeating unit derived from an ethylenically unsaturated acid monomer, and sodium alkane. It includes a sulfonate (sodium alkane sulfonate), and the content of the sodium alkane sulfonate may be included in an amount of 0.7 parts by weight to 4.8 parts by weight based on 100 parts by weight of the total of the carboxylic acid-modified nitrile-based copolymer.

According to an embodiment of the present invention, the sodium alkane sulfonate may be an ionic monomer that can be used as an emulsifier.

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.

Meanwhile, the sodium alkane sulfonate acts as an emulsifier and does not participate in the polymerization reaction, and the content of sodium alkane sulfonate in the latex prepared after the polymerization reaction may be the same as the content of sodium alkane sulfonate introduced at the beginning of the polymerization. have.

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer may include a repeating unit derived from a conjugated diene-based monomer, a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, and a repeating unit derived from an ethylenically unsaturated acid monomer. .

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 40% to 90% by weight, 45% to 80% by weight, or 50% to 78% by weight, based on the total content of the carboxylic acid-modified nitrile-based copolymer. And, within this range, a dip-molded article molded from a dip-molding latex composition containing the carboxylic acid-modified nitrile-based copolymer is flexible, has excellent touch and fit, and has excellent oil resistance and tensile strength.

In addition, 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, hummaronitrile, α-chloronitrile and α -It may be one or more selected from the group consisting of cyanoethyl 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 is 9% to 50% by weight, 15% to 45% by weight, or 20% to 40% by weight, based on the total content of the carboxylic acid-modified nitrile-based copolymer. Within this range, a dip-molded article molded from a dip molding latex composition containing the carboxylic acid-modified nitrile-based copolymer is flexible, has excellent touch and fit, and has excellent oil resistance and tensile strength. .

In addition, according to an embodiment of the present invention, 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 include ethylenically unsaturated 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 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 is 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 carboxylic acid-modified nitrile-based copolymer. Within this range, a dip-molded article molded from a dip-molding latex composition containing the carboxylic acid-modified nitrile-based copolymer is flexible, has excellent fit, and has excellent oil resistance and tensile strength.

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer is derived from an ethylenically unsaturated monomer in addition to a repeating unit derived from a conjugated diene-based monomer, a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, and a repeating unit derived from an ethylenically unsaturated acid monomer. It may optionally further include a repeating unit.

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 20% by weight, 0.01 to 20% by weight, or 0.01 to 15% by weight, based on the total content of the carboxylic acid-modified nitrile-based copolymer. The dip-molded product molded from the dip-molding latex composition containing the present modified nitrile-based copolymer has excellent touch and fit, and excellent tensile strength.

According to an embodiment of the present invention, the sodium alkane sulfonate may include two or more sodium alkane sulfonates having one selected from an alkyl group having 13 to 17 carbon atoms. By using a carboxylic acid-modified nitrile-based copolymer latex containing sodium alkane sulfonate having an alkyl group having 13 to 17 carbon atoms in a straight chain within the above range, defects are significantly reduced during dip molding, and nonvolatile residues are reduced. I can make it. Specifically, the sodium alkane sulfonate has excellent stability because it has high solubility in water compared to sodium dodecylbenzene sulfonate, which was conventionally used as an emulsifier, so that the defect rate of dip molded products can be minimized, and the process of washing the dip molded product with water Since it is well soluble in water and washed away, nonvolatile residues can be significantly reduced.

The sodium alkane sulfonate may have an alkyl group having 13 to 17 carbon atoms, and the sodium alkal sulfonate may be a mixture of sodium alkane sulfonates having one selected from an alkyl group having 13 to 17 carbon atoms.

For example, the sodium alkane sulfonate having 13 to 17 carbon atoms includes at least one sodium alkane sulfonate including one type of alkyl group selected from an alkyl group having 13 to 17 carbon atoms, or selected from an alkyl group having 13 to 17 carbon atoms. It may be a mixture of sodium alkane sulfonates each containing one kind of alkyl group.

As a specific example, the sodium alkane sulfonate having 13 to 17 carbon atoms is sodium alkane sulfonate having an alkyl group having 13 carbon atoms, sodium alkane sulfonate having an alkyl group having 14 carbon atoms, sodium alkane sulfonate having an alkyl group having 15 carbon atoms, It may include two or more sodium alkane sulfonate having an alkyl group and sodium alkane sulfonate having an alkyl group having 17 carbon atoms.

In a more specific example, the sodium alkal sulfonate having 13 to 17 carbon atoms is sodium alkane sulfonate having a linear C13 alkyl group, sodium alkane sulfonate having a linear C14 alkyl group, and a linear C15 alkyl group May be a mixture of sodium alkane sulfonate, sodium alkane sulfonate having a linear C16 alkyl group, and sodium alkane sulfonate having a linear C17 alkyl group.

The sodium alkane sulfonate is included in an amount of 0.7 parts by weight to 4.8 parts by weight based on the total 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer, so that aggregates are not generated during the production of latex, and defects are significantly less generated during dip molding. , When manufacturing latex, it is possible to reduce the amount of emulsifier used, thereby reducing nonvolatile residues in the molded product.

For example, the content of the sodium alkane sulfonate is 0.7 parts by weight to 4.8 parts by weight, 0.8 parts by weight to 4.5 parts by weight, 1 part by weight to 4 parts by weight based on the total 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer. , Or 2 parts by weight to 4 parts by weight. By using a small amount of emulsifier when manufacturing the latex within the above range, it is possible to reduce the content of nonvolatile residual substances in the molded product, and precipitation and coagulation in the latex are suppressed. By suppressing possible defects, the physical properties of the molded product can be improved overall.

In addition, according to an embodiment of the present invention, there is provided a latex composition for dip molding comprising the carboxylic acid-modified nitrile-based copolymer latex according to 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 5% to 40% by weight, 8% to 35% by weight, or 10% to 25% by weight It may be, and within this range, the efficiency of transporting the latex composition is excellent, and there is an effect of excellent storage stability by preventing an increase in the viscosity of the latex composition.

As another example, the latex composition for dip molding 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 product 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 carboxylic acid-modified nitrile-based copolymer in the carboxylic acid-modified nitrile-based copolymer latex is -50 °C to -15 °C, -47 °C to -15 °C, or- It may be 45 ℃ to -20 ℃, while preventing the occurrence of cracks and deterioration of tensile properties such as tensile strength of the molded article dip-molded from the latex composition for dip molding containing the carboxylic acid-modified nitrile-based copolymer latex within the above range. , There is little stickiness, so it has an excellent fit. 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 carboxylic acid-modified nitrile-based copolymer particles in the carboxylic acid-modified nitrile-based copolymer latex is 50 nm to 500 nm, 80 nm to 300 nm, 100 nm to 250 nm Alternatively, it may be 90 nm to 200 nm. Within the above range, the viscosity of the carboxylic acid-modified nitrile-based copolymer latex is not increased, so that the carboxylic acid-modified nitrile-based copolymer latex can be manufactured at a high concentration, and the tensile of the molded article dip-molded from the dip molding latex composition containing the same There is an effect of excellent tensile properties such as strength. 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).

On the other hand, the method for producing a carboxylic acid-modified nitrile-based copolymer latex according to the present invention includes a monomer mixture including a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer; And a step (S10) of preparing a carboxylic acid-modified nitrile-based copolymer latex by mixing sodium alkane sulfonate, wherein the step (S10) includes sodium alkane sulfonate based on 100 parts by weight of the total monomer mixture, 0.7 It may be mixed in parts by weight to 4.8 parts by weight.

That is, the method for producing a carboxylic acid-modified nitrile-based copolymer latex according to the present invention is a mixture of sodium alkane sulfonate in a monomer mixture containing a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer, and polymerization. It may include the step of preparing a carboxylic acid-modified nitrile-based copolymer latex including the carboxylic acid-modified nitrile-based copolymer.

According to an embodiment of the present invention, the polymerization of the carboxylic acid-modified nitrile-based copolymer may be carried out by emulsion polymerization. The polymerization may be carried out by polymerization of the monomer mixture and sodium alkane sulfonate, and each monomer and sodium alkane sulfonate included in the monomer mixture may be added in the type and content of the aforementioned monomers, and batch input , Or can be injected continuously.

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

The emulsifier is added to impart stability to the latex during and after the polymerization reaction, and various types of anionic emulsifiers and nonionic emulsifiers may be used. For example, as anionic emulsifiers, alkyl benzene sulfonates such as sodium alkyl benzene sulfonate, alcohol sulfate, alcohol ether sulfonate, alkyl phenol ether sulfonate, alpha olefin sulfonate, paraffin sulfonate, ester sulfosuccinate, phosphate Esters, and the like, and nonionic emulsifiers may include alkyl phenol ethoxylate, fethiamine ethoxylate, fatty acid ethoxylate, alkanoamide, and the like. These emulsifiers may be used alone or in combination of two or more. In addition, 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 8 parts by weight based on 100 parts by weight of the total content of the monomer mixture, and polymerization stability within this range It is excellent in this, and there is an effect that the amount of foaming is small, making it easy to manufacture a molded article.

In addition, when the polymerization of the carboxylic acid-modified nitrile-based copolymer 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 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 carboxylic acid-modified nitrile-based copolymer includes an activator, the activator is sodium formaldehyde, sulfoxylate, sodium ethylenediamine terraacetate, ferrous sulfate, dextrose, It may be one or more selected from the group consisting of sodium pyrrolate and sodium sulfite. In addition, 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 monomer mixture, and polymerization within this range. It has the effect of maintaining the speed at an appropriate level.

In addition, when the polymerization of the carboxylic acid-modified nitrile-based copolymer includes a molecular weight modifier, the molecular weight modifier is, for example, α-methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, Mercaptans such as octyl mercaptan; 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 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, when the polymerization of the carboxylic acid-modified nitrile-based copolymer includes a polymerization terminator, the polymerization terminator may be, for example, hydroxyl amine, hydroxy amine sulfate, Diethylhydroxy Amine, hydroxy amine sulfonic acid and its alkali metal ions, sodium dimethyl dithiocarbamate, hydroquinone derivatives, hydroxy diethyl benzene dithiocarboxylic acid, hydroxy dibutyl benzene dithiocarboxylic acid And aromatic hydroxy dithiocarboxylic acid, etc. may be included. The polymerization terminator may be added in an amount of 0.05 parts by weight to 2 parts by weight based on 100 parts by weight of the total content of the monomer mixture.

In addition, according to an embodiment of the present invention, the polymerization of the carboxylic acid-modified nitrile-based copolymer 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 dispersing agent, if necessary, Additives such as a pH adjuster, a deoxygenator, a particle size adjuster, an anti-aging agent and an oxygen scavenger 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 carboxylic acid-modified nitrile-based copolymer 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. There is an excellent effect of latex stability within the range.

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

According to an embodiment of the present invention, the sodium alkane sulfonate is mixed as an emulsifier when preparing (polymerization) the carboxylic acid-modified nitrile-based copolymer latex, reducing the amount of the emulsifier to reduce the amount of the carboxylic acid-modified nitrile-based copolymer latex. It is possible to reduce the non-volatile residual material in the molded article molded with the latex composition for dip molding comprising a.

According to an embodiment of the present invention, the preparation of the dip molding latex is a latex composition comprising the carboxylic acid-modified nitrile-based copolymer latex after the step (S10) of preparing the carboxylic acid-modified nitrile-based copolymer latex. It may be performed by further including the step of manufacturing (S20).

According to an embodiment of the present invention, in the step (S20), in addition to the carboxylic acid-modified 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 step of preparing the latex composition for dip molding 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 or 0.3 parts by weight to 5 parts by weight based on 100 parts by weight of the solid content of the carboxylic acid-modified nitrile-based copolymer latex.

When the step of preparing the dip molding latex composition includes a vulcanization accelerator, the vulcanization accelerator is, for example, 2-Mercaptobenzothiazole (MBT), 2,2-dithiobisbenzo Thaazole-2-sulfenamide (2,2-Dithiobisbezothiozolo-2-sulfenamide, MBTS), N-cyclohexylbenzothiazole-2-sulfenamide (N-Cyclehexylbenzothiazole-2-sulfenamide, CBS), 2-morpholino Thiobenzothiazole (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 to 10 parts by weight or 0.3 to 5 parts by weight based on 100 parts by weight of the solid content of the carboxylic acid-modified nitrile-based copolymer latex.

When the step of preparing the latex composition for dip molding is carried out including zinc oxide, the content of zinc oxide is 0.1 to 5 parts by weight or 0.5 based on 100 parts by weight of the solid content of the carboxylic acid-modified nitrile-based copolymer latex. It may be from parts by weight to 2 parts by weight.

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, and an oxygen scavenger may be used as necessary.

The polymerization temperature in the step of preparing a latex composition for dip molding including the carboxylic acid-modified nitrile-based copolymer latex 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 molded article may include 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, and the coagulant solution is a coagulant in water, alcohol, or a mixture thereof. 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 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.

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.

Thereafter, the step of washing the dip molded product may be further included, and a final dip molded product may be obtained after removing impurities such as nonvolatile residues remaining in the dip molded product through the washing step.

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 One

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

A 10L high-pressure reactor equipped with a stirrer, a thermometer, a cooler, and an inlet of nitrogen gas is attached, and a monomer, an emulsifier, and a polymerization initiator are continuously added to the reactor. After replacing the reactor with nitrogen, 32% by weight of acrylonitrile, 1,4 -5 parts by weight of Latemul-PS (KAO) as an emulsifier (2 parts by weight of sodium alkane sulfonate), t-dodecyl mer as an emulsifier based on 100 parts by weight of the monomer mixture containing 62% by weight of butadiene and 6% by weight of methacrylic acid 0.6 parts by weight of captan and 140 parts by weight of ion-exchanged water were added and the temperature was raised to 36°C.

After the temperature was raised, 0.3 parts by weight of potassium persulfate, which is a polymerization initiator, was added, and when the conversion rate reached 94%, 0.1 parts by weight of sodium dimethyl dithiocarbamate was added to stop the polymerization. The unreacted monomer was removed through the deodorization process, and ammonia water, antioxidant, and antifoaming agent were added to obtain a latex having a solid content of 45% and a pH of 8.5.

In addition, the content of sodium alkal sulfonate in Latemul-PS (KAO) used as an emulsifier is 40% by weight, and the sodium alkane sulfonate is sodium alkane sulfonate having an alkyl group having 13 carbon atoms in a straight chain form, a straight chain form Sodium alkane sulfonate having an alkyl group of 14 carbon atoms, sodium alkane sulfonate having a straight-chain alkyl group of 15 carbon atoms, sodium alkane sulfonate having a straight-chain alkyl group having 16 carbon atoms, and sodium alkane sulfonate having a straight-chain alkyl group having 17 carbon atoms It is a mixture of sodium alkane sulfonates including alkane sulfonates.

<Preparation of latex composition for dip molding>

Solid content concentration by adding 1.0 parts by weight of sulfur, 1.5 parts by weight of zinc oxide, 0.7 parts by weight of ZDBC and 3% potassium hydroxide solution and an appropriate amount of secondary distilled water to 100 parts by weight of the prepared carboxylic acid-modified nitrile-based copolymer latex (based on solid content) A latex composition for dip molding of 15% and pH 10.0 was obtained.

<Manufacture of dip molded products>

A coagulant solution was prepared by mixing 12 parts by weight of calcium nitrate, 83.5 parts by weight of ion-exchanged water, 4 parts by weight of calcium carbonate, and 0.5 parts by weight of a wetting agent (Teric 320, produced by Huntsman Corporation, Australia). The hand-shaped ceramic mold was immersed in this solution for 1 minute, pulled out, and dried at 80° C. for 3 minutes to apply a coagulant to the hand-shaped mold.

Then, the mold coated with the coagulant was immersed in the latex composition for dip molding for 15 seconds, pulled up, dried at 80° C. for 2 minutes, and then immersed in water or hot water for 1 minute. Again, the mold was dried at 80° C. for 5 minutes and then crosslinked at 120° C. for 20 minutes. The crosslinked dip molding layer was peeled off from the hand-shaped mold to obtain a glove-shaped dip molding.

Example 2

In Example 1, except for the addition of 7.5 parts by weight (3 parts by weight of sodium alkane sulfonate) instead of 5 parts by weight of Latemul-PS (KAO) when preparing the carboxylic acid-modified nitrile-based copolymer latex. In the same manner as in 1, a glove-shaped dip molded article was obtained.

Example 3

In the above Example 1, except that 10 parts by weight (4 parts by weight of sodium alkane sulfonate) was added instead of 5 parts by weight of Latemul-PS (KAO) when preparing the carboxylic acid-modified nitrile-based copolymer latex. In the same manner as in 1, a glove-shaped dip molded article was obtained.

Example 4

In Example 1, Example 1, except that 2.5 parts by weight (1 part by weight of sodium alkane sulfonate) was added instead of 5 parts by weight of Latemul-PS (KAO) when preparing a carboxylic acid-modified nitrile-based copolymer latex. In the same manner as to obtain a glove-shaped dip molded article.

Comparative example

Comparative example One

In Example 1, except that 1.25 parts by weight (0.5 parts by weight of sodium alkane sulfonate) was added instead of 5 parts by weight of Latemul-PS (KAO) when preparing a carboxylic acid-modified nitrile-based copolymer latex. In the same manner as in 1, a glove-shaped dip molded article was obtained.

Comparative example 2

In Example 1, except that 12.5 parts by weight (5 parts by weight of sodium alkane sulfonate) was added instead of 5 parts by weight of Latemul-PS (KAO) when preparing a carboxylic acid-modified nitrile-based copolymer latex. In the same manner as in 1, a glove-shaped dip molded article was obtained.

Comparative example 3

In Example 1, when preparing a carboxylic acid-modified nitrile-based copolymer latex, an emulsifier containing 2 parts by weight of sodium dodecylbenzene sulfonate (that is, 2 parts by weight of an active ingredient) was added instead of Latemul-PS (KAO). Except for that, in the same manner as in Example 1, a glove-shaped dip-molded article was obtained.

Experimental example

Experimental example One

The polymerization stability of the carboxylic acid-modified nitrile-based copolymer latex prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was measured under the following conditions and is shown in Table 1 below.

* Polymerization stability (ppm): The polymerization stability of the prepared carboxylic acid-modified nitrile-based copolymer latex was passed through 200 mesh, and the amount of the aggregate was calculated on a solid basis and expressed in parts per million (ppm).

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 stability
[ppm] 85 62 41 107 263 46 121

Referring to Table 1, it can be seen that in the case of the carboxylic acid-modified nitrile-based copolymer latex of Examples 1 to 4, the amount of the aggregate is 107 ppm or less, which has excellent polymerization stability.

In comparison, the polymerization stability of Comparative Example 1 containing less than the content range of sodium alkane sulfonate according to the present invention and Comparative Example 3 using sodium dodecylbenzene sulfonate having an aryl group instead of sodium alkane sulfonate It was confirmed that this decreases.

Experimental example 2

Tensile strength, elongation, stress at 300% elongation, nonvolatile residual material, and pinholes of the dip-molded products prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were measured under the following conditions and are shown in Table 2 below.

* Tensile strength (MPa), elongation (%), and stress at 300% elongation (MPa): For the dip-molded products obtained in each Example and Comparative Example, a dumbbell-shaped test piece was prepared according to ASTM D-412. . Subsequently, this test piece was pulled at an elongation speed of 500 mm/min using a UTM (Universal Testing Machine), and the tensile strength at break, the elongation at break, and the stress at the elongation at 300% were measured.

* Non-volatile residual material (ppm): For the dip-molded product obtained in each Example and Comparative Example, ^{cut into 100 cm 2} size specimens and weighed, and then immersed the specimen in a bottle containing 200 g of distilled water at 60°C. Put in a kept constant temperature shaker, extract the residue from the specimen for 30 minutes, dry it in an oven at 135° C. for 40 minutes, and measure the weight. The difference in weight before and after extraction was divided by the weight of distilled water to calculate the amount of nonvolatile residues.

* Pinhole measurement: The number of pinholes in each of the 10 dip-molded products prepared in each Example and Comparative Example was visually observed and evaluated according to the following criteria.

◎: No pinhole

○: 1 pinhole occurs

△: occurrence of 2 to 3 pinholes

Ｘ: More than 4 pinholes occur

Tensile strength (MPa) Elongation(%) Stress at 300% elongation (MPa) Non-volatile residue (ppm) Pinhole Example 1 37.4 582 6.9 47 ◎ Example 2 36.9 593 6.7 61 ◎ Example 3 37.0 613 6.6 87 ○ Example 4 38.1 579 7.0 35 △ Comparative Example 1 34.2 520 7.0 32 X Comparative Example 2 32.7 563 6.8 126 △ Comparative Example 3 33.1 556 6.3 134 X

Nonvolatile residue (NVR) remaining in the glove consists of an emulsifier used in latex polymerization, a flocculant used in the glove manufacturing process, and wax. If the amount of the emulsifier is reduced during the manufacture of latex, the nonvolatile residual material in the glove can be greatly reduced, but there may be a problem of an increase in aggregates during the manufacture of latex. Due to the nature of latex, a lot of aggregates may be generated in the reactor or in the stirrer during manufacture. They act as impurities in the subsequent process, and when performed as a continuous process, it can cause many problems such as non-uniformity in physical properties. As time and effort are involved, problems that can have a profound impact on workability and productivity may occur.

Referring to Table 2, Examples 1 to 4 according to the present invention include a carboxylic acid-modified nitrile-based copolymer latex containing sodium alkane sulfonate in an appropriate range in the latex composition for dip molding, physical properties It was confirmed that the amount of non-volatile residual material was significantly reduced without deterioration of.

In particular, in Examples 1 to 3, further, it was confirmed that the number of pinholes that may be generated while solidified matters are adsorbed to the dip-molded product is significantly reduced. Through this, Examples 1 to 3 significantly reduce the amount of nonvolatile residual substances by reducing the amount of emulsifier used, and at the same time, prevent the increase of aggregates, thereby improving workability and productivity according to the reduction of aggregates. It was confirmed that defects can be significantly reduced.

On the other hand, in the case of Comparative Example 1 in which the content of sodium alkane sulfonate is smaller than the content according to the present invention, the nonvolatile residual material is small, but it is difficult to produce a dip molded article due to the occurrence of many pinholes. In the case of Comparative Example 2, there is a problem that the amount of non-volatile residual material is large and pinholes are generated, and in the case of Comparative Example 3 including sodium dodecylbenzene sulfonate instead of sodium alkane sulfonate, the amount of non-volatile residual material is significantly increased. And it was confirmed that a number of pinholes occurred.

Claims (11)

A carboxylic acid-modified nitrile-based copolymer comprising a repeating unit derived from a conjugated diene-based monomer, a repeating unit derived from an ethylenically unsaturated nitrile-based monomer, and a repeating unit derived from an ethylenically unsaturated acid monomer, and
Containing sodium alkane sulfonate,
The content of the sodium alkane sulfonate is a carboxylic acid-modified nitrile-based copolymer latex contained in an amount of 0.7 to 4.8 parts by weight based on 100 parts by weight of the total of the carboxylic acid-modified nitrile-based copolymer. The method of claim 1,
The sodium alkane sulfonate is a carboxylic acid-modified nitrile-based copolymer latex containing two or more kinds of sodium alkane sulfonate having one selected from an alkyl group having 13 to 17 carbon atoms. The method of claim 1,
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 Carboxylic acid-modified nitrile-based copolymer latex comprising a. The method of claim 1,
The ethylenically unsaturated nitrile-based monomer includes at least one selected from the group consisting of acrylonitrile, methacrylonitrile, hummaronitrile, α-chloronitrile and α-cyano ethyl acrylonitrile. Nitrile-based copolymer latex. The method of claim 1,
The ethylenically unsaturated acid monomer is a carboxylic acid-modified nitrile-based copolymer latex which is an ethylenically unsaturated monomer containing an acidic group such as a carboxyl group, a sulfonic acid group, and an acid anhydride group. The method of claim 1,
The content of the sodium alkane sulfonate is a carboxylic acid-modified nitrile-based copolymer latex contained in an amount of 1 to 4 parts by weight based on 100 parts by weight of the total of the carboxylic acid-modified nitrile-based copolymer. The method of claim 1,
Based on the total content of the carboxylic acid-modified nitrile-based copolymer, 40% to 90% by weight of repeating units derived from conjugated diene-based monomers, 9% to 50% by weight of repeating units derived from ethylenically unsaturated nitrile-based monomers, and ethylenically unsaturated acid monomers The carboxylic acid-modified nitrile-based copolymer latex containing 0.1% to 15% by weight of the derived repeating unit. A monomer mixture comprising a conjugated diene monomer, an ethylenically unsaturated nitrile monomer, and an ethylenically unsaturated acid monomer, and sodium alkane sulfonate are mixed to prepare a carboxylic acid-modified nitrile-based copolymer latex (S10),
The step (S10) is a method for producing a carboxylic acid-modified nitrile-based copolymer latex in which sodium alkane sulfonate is mixed in an amount of 0.7 parts by weight to 4.8 parts by weight based on 100 parts by weight of the monomer mixture. The method of claim 8,
The step (S10) is a method for producing a carboxylic acid-modified nitrile-based copolymer latex in which sodium alkane sulfonate is mixed in an amount of 1 to 4 parts by weight based on the total 100 parts by weight of the monomer mixture. A latex composition for dip molding comprising the carboxylic acid-modified nitrile-based copolymer latex according to any one of claims 1 to 7. A dip molded article comprising a layer derived from the latex composition for dip molding according to claim 10.