KR20190073694A - Method for preparing carboxylic acid modified nitrile based copolymer latex, carboxylic acid modified nitrile based copolymer latex and article formed by the latex - Google Patents

Abstract

The present invention relates to a producing method of carboxylic acid-modified nitrile-based copolymer latex and, more specifically, to a carboxylic acid-modified nitrile-based copolymer latex producing method which includes: a step (S10) of polymerizing a conjugated diene-based monomer, an ethylenically unsaturated nitrile-based monomer, and an ethylenically unsaturated acid monomer; a step (S20) of adding and polymerizing a carbonyl group-containing acrylic monomer when a polymerization conversion rate is 60% or more during the polymerization of the step (S10); and a step (S30) of adding and stirring dicarboxylic acid dihydrazide on carboxylic acid-modified nitrile-based copolymer latex which has pH 7.0 or more after the polymerization completion of the step (S20). In the producing method of carboxylic acid-modified nitrile-based copolymer latex and a formed product formed by the same, the content of the carbonyl group-containing acrylic monomer added in the step (S20) is more than 0 wt% to less than 3 wt% with respect to the total amount of the monomer mixture; and the content of the dicarboxylic acid dihydrazide added in the step (S30) is more than 0 parts by weight to less than 3 parts by weight with respect to 100 parts by weight of the total amount of the monomer mixture. The present invention reduces sticky feeling and improves durability and chemical resistance without using sulfur and vulcanization accelerators.

Description

TECHNICAL FIELD [0001] The present invention relates to a process for producing a carboxylic acid-modified nitrile-based copolymer latex, a carboxylic acid-modified nitrile-based copolymer latex, and a molded article formed from the same. BACKGROUND OF THE INVENTION [0001] }

The present invention relates to a process for producing a carboxylic acid-modified nitrile-based copolymer latex, and more particularly to a process for producing a carboxylic acid-modified nitrile-based copolymer latex, a carboxylic acid-modified nitrile-based copolymer latex prepared therefrom, .

Rubber gloves are increasingly used in various fields such as household, food, electronics, and medical fields. In the past, rubber gloves made by deep molding of natural rubber latex were used in many cases. However, since natural rubber causes serious protein allergy such as pain and rash to some users, recently, Gloves made by dipping a latex composition containing a vulcanization accelerator are widely used.

However, in the case of sulfur crosslinked gloves made by dip-molding synthetic rubber latex in recent years, vulcanization accelerators used during sulfur crosslinking, for example, vulcanization accelerators such as thiuram-based, carbamate- And allergic rhinitis in the United States.

The zinc oxide used in the crosslinking of the synthetic rubber latex together with the sulfur and the vulcanization accelerator plays the role of forming the ionic bond with the carboxylic acid of the synthetic rubber latex to increase the strength of the dip product. There is a problem that the bonding is weakened, which causes the strength and durability of the glove to deteriorate when the user is working in an acidic environment, and there is a possibility that the zinc ions are eluted and transferred to the work material. Particularly, perspiration of a person including electrolytes, urea, citric acid, ammonia and the like as main components has a weak acidity. The ionic bond between the carboxylic acid and the zinc ion can be weakened by the acid component of such sweat, The glove tears easily, resulting in durability problems.

In recent years, a synthetic rubber latex using a polyvalent metal cationic compound has been proposed without using sulfur, a vulcanization accelerator and zinc oxide to solve the above problems, but in this case, the physical properties and durability of the sulfur bridging glove are not satisfied In fact. Various methods for producing non-sulfur and non-sulfur vulcanizing accelerator gloves such as adding various kinds of crosslinkable materials to synthetic rubber latex have been proposed, but the durability and chemical resistance of satisfactory levels have not yet been secured .

Therefore, continuous research and development are required to ensure durability and chemical resistance of non-sulfur and non-sulfur accelerator gloves.

KR 2014-0053859 A

It is an object of the present invention to solve the problems mentioned in the background of the present invention by providing a process for producing a dip molded article which can reduce the tackiness of the produced dip molded article without using sulfur and a vulcanization accelerator, Durability and chemical resistance.

That is, the present invention has been made in order to solve the problems of the prior art, and it is an object of the present invention to provide a process for producing a carboxylic acid-modified nitrile-based copolymer latex capable of crosslinking during molding of a dip molded article without using sulfur and a vulcanization accelerator, It is an object of the present invention to provide a dip molded article which is dip-formed with the carboxylic acid modified nitrile-based copolymer latex thus produced, has less tackiness, and is excellent in durability and chemical resistance.

According to one embodiment of the present invention for solving the above problems, the present invention provides a method for producing a thermoplastic resin composition, comprising: (S10) polymerizing a conjugated diene monomer, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid monomer; A step (S20) of charging and polymerizing a carbonyl group-containing acrylic monomer at a polymerization conversion rate of 60% or more during the polymerization in the step (S10); And (S30) adding and stirring dicarboxylic acid dihydrides to the carboxylic acid modified nitrile-based copolymer latex having a pH of 7.0 or more after completion of the polymerization in the step (S20). The content of the monomer having a carbonyl group is not less than 0% by weight and less than 3% by weight based on the total amount of the monomer mixture, and the amount of the dicarboxylic acid dihydrazide added in the step (S30) The present invention provides a process for producing a carboxylic acid-modified nitrile-based copolymer latex having an amount of more than 0 parts by weight and less than 3 parts by weight based on 100 parts by weight of the total mixture.

Further, the present invention relates to 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, a repeating unit derived from an ethylenically unsaturated acid monomer and a repeating unit derived from a carbonyl- And a dicarboxylic acid dihydrazide, wherein all or a part of the carbonyl group-containing acrylic monomer-derived repeating unit is distributed on the surface of the carboxylic acid-modified nitrile-based copolymer latex, and the repeating unit derived from the carbonyl group- The content of the dicarboxylic acid dihydrazide is preferably in the range of more than 0% by weight to less than 3% by weight based on the total amount of the repeating units derived from each monomer, And a carboxylic acid-modified nitrile-based copolymer latex in an amount of more than 0 parts by weight to less than 3 parts by weight.

Further, the present invention provides a molded article comprising the carboxylic acid-modified nitrile-based copolymer latex-derived layer.

When a carboxylic acid-modified nitrile-based copolymer latex is produced according to the present invention and a dipped molded article is molded using the same, the dope-molded product is less tacky and excellent in durability and chemical resistance without using sulfur and a vulcanization accelerator .

The terms and words used in the description of the present invention and in the claims should not be construed to be limited to ordinary or dictionary terms and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The term " monomer-derived repeating unit " in the present invention refers to a component derived from a monomer, a structure thereof, or a substance itself, and when the polymer is polymerized, the introduced monomer means a repeating unit .

The term " latex " in the present invention may mean that a polymer or a polymer polymerized by polymerization is present in a form dispersed in water. Specific examples thereof include rubber-like polymers polymerized by emulsion polymerization or fine particles of a copolymer May be present in a form dispersed in water in a colloidal state.

The term " carboxylic acid-modified nitrile-based copolymer latex " in the present invention refers to a state in which all of the carboxylic acid-modified nitrile-based copolymer and additives for molding a dip-shaped article on the latex are contained, May refer to a cohesive latex composition.

The term 'monomer mixture' in the present invention may mean that all of the monomers to be added in the production of the carboxylic acid-modified nitrile-based copolymer are included. Specific examples thereof include conjugated diene-based monomers, ethylenically unsaturated nitrile-based monomers, ethylenically unsaturated A monomer mixture containing an acid monomer and a carbonyl group-containing acrylic monomer, and more specifically, when it further includes an ethylenically unsaturated monomer as required, it may be a conjugated diene monomer, an ethylenically unsaturated nitrile monomer, an ethylenically unsaturated May mean a monomer mixture comprising an acid monomer, a carbonyl group-containing acrylic monomer and an ethylenically unsaturated monomer.

In the present invention, the term "crosslinking moiety" may refer to a component or structure derived from a compound, and may be a cross linking moiety formed by a crosslinking reaction to perform a cross linking function in a polymer or between polymers. .

The term " layer derived " in the present invention may refer to a layer formed from a polymer or a copolymer, and specific examples include, in the production of a dip product, a polymer or copolymer is attached, fixed, and / But may be a layer formed from a copolymer.

The process for producing a carboxylic acid-modified nitrile-based copolymer latex according to the present invention comprises: (S10) polymerizing a conjugated diene monomer, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid monomer; A step (S20) of charging and polymerizing a carbonyl group-containing acrylic monomer at a polymerization conversion rate of 60% or more during the polymerization in the step (S10); And (S30) adding and stirring dicarboxylic acid dihydrides to the carboxylic acid modified nitrile-based copolymer latex having a pH of 7.0 or more after completion of the polymerization in the step (S20). The content of the monomer having a carbonyl group is not less than 0% by weight and less than 3% by weight based on the total amount of the monomer mixture, and the amount of the dicarboxylic acid dihydrazide added in the step (S30) May be more than 0 parts by weight and less than 3 parts by weight based on 100 parts by weight of the total mixture.

According to an embodiment of the present invention, the polymerization in the step (S10) is a step for producing a carboxylic acid-modified nitrile-based copolymer, wherein the conjugated diene monomer, the ethylenically unsaturated nitrile monomer and the ethylenic unsaturated acid monomer May be carried out by copolymerization at the same time.

According to an embodiment of the present invention, the polymerization in the step (S10) may be carried out by emulsion polymerization, and each monomer may be simultaneously introduced into the polymerization reactor prior to polymerization, and a part of the monomers may be introduced into the polymerization reactor And adding the remaining monomer after the initiation of the polymerization.

According to one embodiment of the present invention, the conjugated diene-based monomer is a monomer for forming a repeating unit derived from a conjugated diene monomer contained in a carboxylic acid-modified nitrile-based copolymer, and includes 1,3-butadiene, 2,3- Butadiene, dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and isoprene. Specific examples thereof may be 1,3-butadiene or isoprene , More specifically, 1,3-butadiene. The content of the conjugated diene monomer may be 40 wt% to 89 wt%, 45 wt% to 80 wt%, or 50 wt% to 78 wt% based on the total amount of the monomer mixture, The dip-molded article molded from the carboxylic acid-modified nitrile-based copolymer latex containing the modified nitrile-based copolymer is flexible, excellent in feeling of wearing, and excellent in oil resistance and tensile strength.

According to an embodiment of the present invention, the ethylenically unsaturated nitrile monomer is a monomer for forming a repeating unit derived from an ethylenically unsaturated nitrile monomer contained in a carboxylic acid-modified nitrile-based copolymer, and includes acrylonitrile, Acrylonitrile, methacrylonitrile, fumaronitrile,? -Chloronitrile and? -Cyanoethyl acrylonitrile, and specific examples thereof may include acrylonitrile and methacrylonitrile, and more specifically, For example, it may be acrylonitrile. The content of the ethylenically unsaturated nitrile monomer may be from 10% by weight to 50% by weight, from 15% by weight to 45% by weight, or from 20% by weight to 40% by weight based on the total amount of the monomer mixture, The dip-molded article molded from the carboxylic acid-modified nitrile-based copolymer latex containing the naturally-occurring denatured nitrile-based copolymer is flexible, excellent in wearing feeling, and excellent in oil resistance and tensile strength.

According to an embodiment of the present invention, the ethylenically unsaturated acid monomer is a monomer for forming a repeating unit derived from an ethylenically unsaturated acid monomer contained in a carboxylic acid-modified nitrile-based copolymer, and may be a carboxyl group, a sulfonic acid group, An ethylenically unsaturated monomer containing an acid group such as an anhydride group, and specific examples thereof include ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid; Polycarboxylic anhydrides such as maleic anhydride and citraconic anhydride; Ethylenically unsaturated sulfonic acid monomers such as styrenesulfonic acid; Ethylenically unsaturated polycarboxylic acid partial ester monomers such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate. More specific examples thereof include acrylic acid, methacrylic acid , Itaconic acid, maleic acid, and fumaric acid, and more specific examples thereof may be methacrylic acid. The ethylenic unsaturated acid monomer may be used in the form of a salt such as an alkali metal salt or an ammonium salt at the time of polymerization. Also, the content of the ethylenic unsaturated acid monomer may be 0.1 wt% to 10 wt%, 0.5 wt% to 9 wt%, or 1 wt% to 8 wt% based on the total amount of the monomer mixture, The dip-molded article formed from the carboxylic acid-modified nitrile-based copolymer latex is flexible, has excellent wearing feeling, and has an excellent tensile strength.

In addition, according to an embodiment of the present invention, the polymerization in the step (S10) may be carried out by reacting a conjugated diene monomer, an ethylenically unsaturated nitrile monomer and an ethylenic unsaturated acid monomer with ethylene And may further include an unsaturated monomer. The ethylenically unsaturated monomer is a monomer for forming a repeating unit derived from an ethylenic unsaturated monomer, and includes aromatic vinyl monomers such as styrene, arylstyrene, and vinylnaphthalene; (Meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl The same ethylenically unsaturated amide monomers; Non-conjugated monomers such as vinyl pyridine, vinyl norbornene, dicyclopentadiene and 1,4-hexadiene; Acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (Meth) acrylate, dibutyl fumarate, diethyl maleate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, cyanomethyl Ethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, 2-ethyl 6-cyanooyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl , Ethylenically unsaturated carboxylic acid ester monomers such as glycidyl (meth) acrylate and dimethylaminoethyl (meth) acrylate, and the like. When the polymerization in the step (S10) is further carried out with an ethylenically unsaturated monomer, the content of the ethylenically unsaturated monomer may be from 0.01% by weight to 20% by weight based on the total amount of the monomer mixture, The balance between the tensile strength and the soft touch of the dip molded article is excellent.

Further, according to an embodiment of the present invention, the polymerization in the step (S10) may be carried out in the presence of an emulsifier, a polymerization initiator, a molecular weight modifier, and the like.

When the polymerization in the step (S10) is carried out in the presence of an emulsifier, the emulsifier may be at least one selected from the group consisting of an anionic surfactant, a nonionic surfactant, a cationic surfactant and a positive surfactant, Specific examples thereof include at least one anionic surfactant selected from the group consisting of alkylbenzenesulfonic acid salts, aliphatic sulfonic acid salts, higher alcohol sulfuric acid ester salts,? -Olefin sulfonic acid salts and alkyl ether sulfuric acid ester salts. The emulsifier may be added in an amount of 0.3 to 10 parts by weight, 0.8 to 8 parts by weight, or 1.5 to 6 parts by weight based on 100 parts by weight of the total amount of the monomer mixture. Within this range, And the production of a molded article is easy because of the small amount of bubble generation.

When the polymerization in the step (S10) is carried out in the presence of a polymerization initiator, the polymerization initiator may be a radical initiator, and specific examples thereof include sodium persulfate, potassium antacid, ammonium persulfate, potassium perphosphate and hydrogen peroxide Inorganic peroxides; t-butyl peroxide, cumene hydroperoxide, p-menthol hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide Organic peroxides such as oxides, 3,5,5-trimethylhexanol peroxide and t-butyl peroxyisobutyrate; Nitrogen compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobisisobutyronitrile (butyl acid) methyl, and the like, As a specific example, it may be an inorganic peroxide, and more specifically, it may be a persulfate. The polymerization initiator may be added in an amount of 0.01 to 2 parts by weight, 0.02 to 1.5 parts by weight, or 0.05 to 1 part by weight based on 100 parts by weight of the total amount of the monomer mixture. Within this range, Can be maintained at an appropriate level, and the polymerization stability is excellent.

When the polymerization in step (S10) is carried out using a molecular weight modifier, the molecular weight modifier may be, for example,? -Methylstyrene dimer; mercaptans such as t-dodecylmercaptan, n-dodecylmercaptan and octylmercaptan; Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride and methylene bromide; Sulfur-containing compounds such as tetraethylthiuram disulfide, dipentamethylenethiuramdisulfide, and diisopropylxanthogen disulfide, and specific examples thereof may be t-dodecylmercaptan. The molecular weight modifier may be added in an amount of 0.1 part by weight to 2 parts by weight, 0.2 part by weight to 1.5 parts by weight, or 0.3 parts by weight to 1.0 part by weight based on 100 parts by weight of the entire monomer mixture. Within this range, And excellent physical properties of a molded article at the time of producing a molded article after polymerization.

Also, according to one embodiment of the present invention, the polymerization may be carried out with an activator, which may be, for example, sodium formaldehyde, sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, At least one selected from the group consisting of sodium chloride, sodium chloride, sodium chloride, sodium chloride and sodium sulfite. The activator may be added in an amount of 0.001 to 5 parts by weight based on 100 parts by weight of the total amount of the main monomer.

According to an embodiment of the present invention, the polymerization may be carried out in water as a medium, specifically, deionized water. In order to ensure polymerization easiness, a chelating agent, a dispersant, a pH adjuster, a deoxidizer, , An antioxidant and an oxygen scavenger, and the like. According to one embodiment of the present invention, the emulsifier, the polymerization initiator, the molecular weight modifier, the additive, etc. may be added to the polymerization reactor as a batch or separately, as in the case of the main monomer.

According to an embodiment of the present invention, the polymerization 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, and within this range, .

According to an embodiment of the present invention, the polymerization in the step (S20) may be carried out by further adding a carbonyl group-containing acrylic monomer during the polymerization in the step (S10), and then adding the monomer charged in the step (S10) The step of polymerizing the conjugated diene monomer, the ethylenically unsaturated nitrile monomer, and the ethylenic unsaturated acid monomer (B) in the presence of the conjugated diene monomer, the ethylenically unsaturated nitrile monomer, and the ethylenic unsaturated acid monomer And at the same time.

According to one embodiment of the present invention, the carbonyl group-containing acrylic monomer charged in the step (S20) is a self-crosslinking (self-crosslinking) copolymer of a carboxylic acid- modified nitrile- a monomer for forming a repeating unit derived from a carbonyl group-containing acrylic monomer contained in a back bone of a carboxylic acid-modified nitrile-based copolymer so that cross-linking can be performed, and may be diacetone acrylamide, Amide. The acrylic monomer containing a carbonyl group is a monomer having an acrylic functional group in a carbonyl group-containing acrylic monomer participating in a radical reaction upon polymerization to form a repeating unit, and a carbonyl group in a carbonyl group-containing acrylic monomer and a hydrazide of a dicarboxylic acid dihydrazide It is possible to form a crosslinked part of the carboxylic acid-modified nitrile-based copolymer or a crosslinked part of the carboxylic acid-modified nitrile-based copolymer through the reaction of the carboxyl group-modified nitrile-based copolymer, Thus, it is possible to prevent side effects of the dip-formed article due to the cross-linking agent, while exhibiting excellent durability and chemical resistance.

According to an embodiment of the present invention, the carbonyl group-containing acrylic monomer charged in step (S20) has a polymerization conversion rate of 60% or more, 60% to 90%, 60% to 80%, or 61% to 80% Can be injected at the point of time. The carbonyl group-containing acrylic monomer is added at the beginning of the polymerization, that is, with the conjugated diene monomer, the ethylenically unsaturated nitrile monomer and the ethylenic unsaturated acid monomer to be charged in the step (S10) However, in this case, the repeating unit derived from the carbonyl group-containing acrylic monomer derived from the carbonyl group-containing acrylic monomer in the polymerized carboxylic acid-modified nitrile-based copolymer is randomly distributed, and accordingly, the carboxylic acid-modified nitrile- That is, in the latex, the degree of exposure of the carbonyl group on the repeating unit derived from the carbonyl group-containing acrylic monomer may decrease during autogenous crosslinking, and the crosslinking ability may be lowered. However, according to the present invention, when the carbonyl group-containing acrylic monomer is introduced at the time of the polymerization conversion rate, it is possible to concentrate the repeating unit derived from the carbonyl group-containing acrylic monomer onto the surface of the carboxylic acid modified nitrile-based copolymer latex, The cross-linking ability is improved, and accordingly, the durability and the chemical resistance of the formed deep-molded product are improved.

According to one embodiment of the present invention, the polymerization conversion rate may be calculated by taking a certain amount of the sample from the composition under reaction at a predetermined time interval, and measuring the content of the solid content in the sample, .

[Equation 1]

Polymerization Conversion (%) = (Ms - Mo) / (Mp - M'o)

In the above formula (1), Ms is the weight of the dried copolymer, Mo is the sum of the weight of the emulsifier and the polymerization initiator, Mp is the weight of the 100% polymerized copolymer, M'o is the sum of the weight of the emulsifier and the polymerization initiator to be.

According to an embodiment of the present invention, the content of the carbonyl group-containing acrylic monomer added in the step (S20) is more than 0 wt% to less than 3 wt%, 0.01 wt% to 2.5 wt% , Or 0.1% by weight to 2% by weight, and within this range, repeating units derived from repeating units derived from a conjugated diene monomer, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid monomer in accordance with increase in repeating units derived from an acrylic monomer containing a carbonyl group There is an effect of remarkably improving the durability and chemical resistance while preventing deterioration of mechanical properties such as tensile properties due to lowering of the content of the unit.

According to an embodiment of the present invention, the method for preparing a carboxylic acid-modified nitrile-based copolymer latex comprises the steps of: (S10) terminating the polymerization reaction in step (S20) to obtain a carboxylic acid-modified nitrile-based copolymer latex (S21). At this time, the polymerization reaction may be terminated at a polymerization conversion rate of 85% or more, 88% to 99.9%, or 90% to 99%. The method for producing a carboxylic acid-modified nitrile-based copolymer latex may further include a step (S22) of removing unreacted monomers by a deodorization process after the completion of the reaction.

According to an embodiment of the present invention, the stirring in the step (S30) may be carried out after the completion of the polymerization in the step (S20), on the carboxylic acid-modified nitrile copolymer latex having the pH of 7.0 prepared in the step (S20) A step of adding dicarboxylic acid dihydrazide and stirring to disperse the dicarboxylic acid dihydrazide in the carboxylic acid-modified nitrile-based copolymer latex. The dicarboxylic acid dihydrazide is used to induce a self-crosslinking reaction with a carbonyl group present in a repeating unit derived from an acrylic monomer containing a carbonyl group formed by the introduction of the step (S20). As described above, The role of forming a crosslinked portion in the carboxylic acid-modified nitrile-based copolymer or the carboxylic acid-modified nitrile-based copolymer through reaction of the carbonyl group in the acrylic monomer-derived repeating unit with the hydrazide group of the dicarboxylic acid dihydrazide Can be performed.

According to an embodiment of the present invention, the dicarboxylic acid dihydrazide introduced in the step (S30) may be adipic acid dihydrazide, and specific examples thereof may include adipic acid dihydrazide, In this case, the length of the self-crosslinking portion formed by the carbonyl-hydrazide reaction is appropriate, and the mechanical properties of the dip-molded article are excellent.

According to an embodiment of the present invention, in step (S30), the dicarboxylic acid dihydrazide may be a carboxylic acid-modified nitrile compound having a pH of 7.0 or higher, 7.0 to 10.0, 7.0 to 9.0, or 7.2 to 8.5 May be injected onto the copolymer latex. When the dicarboxylic acid dihydrazide is added to a carboxylic acid-modified nitrile-based copolymer latex having a pH of less than 7.0, hardening occurs rapidly, external crosslinking does not occur smoothly, and the effect of improving stickiness, durability and chemical resistance is improved , It may be preferable to add the dicarboxylic acid dihydrazide to the carboxylic acid-modified nitrile-based copolymer having a pH of 7.0 or more.

According to an embodiment of the present invention, the amount of the dicarboxylic acid dihydrazide to be added in the step (S30) is in the range of more than 0 parts by weight to less than 3 parts by weight based on 100 parts by weight of the total amount of the monomer mixture, 0.01 part by weight to 2.5 parts by weight, or 0.1 part by weight to 2 parts by weight. Within this range, stickiness of the dip-molded article is remarkably lowered, and durability and chemical resistance of the dip-molded article are excellent.

The present invention also provides a carboxylic acid-modified nitrile-based copolymer latex prepared according to the process for producing a carboxylic acid-modified nitrile-based copolymer latex. The carboxylic acid-modified nitrile-based copolymer latex can be obtained by subjecting a carboxylic acid-modified nitrile-based copolymer latex to a carboxylic acid-modified repeating unit containing repeating units derived from conjugated dienic monomer, repeating units derived from ethylenically unsaturated nitrile monomer, repeating units derived from ethylenic unsaturated acid monomers and repeating units derived from acrylonitrile- Nitrile-based copolymers; And a dicarboxylic acid dihydrazide, wherein all or a part of the carbonyl group-containing acrylic monomer-derived repeating unit is distributed on the surface of the carboxylic acid-modified nitrile-based copolymer latex, and the repeating unit derived from the carbonyl group- The content of the dicarboxylic acid dihydrazide is preferably in the range of more than 0% by weight to less than 3% by weight based on the total amount of the repeating units derived from each monomer, And more preferably 0 parts by weight to less than 3 parts by weight.

According to one embodiment of the present invention, each of the monomer-derived repeating units contained in the carboxylic acid-modified nitrile-based copolymer is formed by polymerization from a monomer described as a monomers which can be added in the above-described method for producing a carboxylic acid-modified nitrile- And the content of each monomer-derived repeating unit may be the same as the content of the above-mentioned input monomer. In addition, the dicarboxylic acid dihydrazide may be the same kind and the same amount as the dicarboxylic acid dihydrazide described above.

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer latex may be prepared by copolymerizing a carboxylic acid-modified nitrile-based copolymer and a dicarboxylic acid dihydrazide in a carboxylic acid-modified nitrile- And at the same time, by the self-crosslinking reaction between the carbonyl group of the repeating unit derived from the carbonyl group-containing acrylic monomer in the carboxylic acid-modified nitrile-based copolymer and the hydrazide of the dicarboxylic acid dihydrazide, Modified carboxylic acid-modified nitrile-based copolymer.

According to an embodiment of the present invention, the repeating units derived from the carbonyl group-containing acrylic monomers may be all or part of those distributed on the surface of the carboxylic acid-modified nitrile-based copolymer latex. Specific examples thereof include acrylic group- The content of the repeating unit derived from the carbonyl group-containing acrylic monomer is greater than the content of the repeating unit derived from the carbonyl group-containing acrylic monomer containing carbonyl group, which is formed when the monomer is introduced at the beginning of polymerization or at a polymerization conversion rate of less than 60% . In this case, stickiness of the deep-formed product is remarkably lowered, and durability and chemical resistance of the deep-molded product are excellent. As described above, in the case of the carboxylic acid-modified nitrile-based copolymer latex prepared by charging the acrylic monomer containing a carbonyl group together with the ethylenically unsaturated nitrile monomer and the ethylenic unsaturated acid monomer or by introducing the monomer at a polymerization conversion rate of less than 60% The repeating unit derived from the carbonyl group-containing acrylic monomer derived from the carbonyl group-containing acrylic monomer in the polymerized carboxylic acid-modified nitrile-based copolymer is randomly distributed in the polymerized nitrile-based copolymer, Distribution, that is, in the latex, the degree of exposure of the carbonyl group on the repeating unit derived from an acrylic monomer containing a carbonyl group is lowered during autogenous crosslinking, and the crosslinking ability may be lowered. However, the carboxylic acid-modified nitrile-based copolymer latex prepared according to the process for producing a carboxylic acid-modified nitrile-based copolymer latex of the present invention is characterized in that the repeating unit derived from the carbonyl group-containing acrylic monomer is concentrated on the surface of the carboxylic acid- And the cross-linking ability is improved at the time of self-crosslinking. Thus, the durability and chemical resistance of the formed dip-molded article are improved.

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer of the carboxylic acid-modified nitrile-based copolymer latex may have a glass transition temperature of -50 ° C to -15 ° C or -45 ° C to -20 ° C And has an excellent tensile strength within this range, and has an effect of preventing cracking of the dip-formed article. The glass transition temperature may be measured by Differential Scanning Calorimetry.

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer of the carboxylic acid-modified nitrile-based copolymer latex may have an average particle diameter of 50 nm or more, 50 nm to 500 nm, 50 nm to 300 nm, or 60 nm to 200 nm. Within this range, it is possible to prevent the viscosity increase of the carboxylic acid-modified nitrile-based copolymer latex, to produce latex at a high concentration, and to prevent deterioration of the tensile strength of the dip- have. The average particle size may be measured with a laser scattering analyzer (Nicomp).

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer latex may be at least one selected from the group consisting of a pigment such as titanium oxide, a filler such as silica, a thickener, and a pH adjuster such as ammonia or alkali hydroxide Modified nitrile-based copolymer latex composition further comprising the above-mentioned additives. As described above, when the carboxylic acid-modified nitrile-based copolymer latex further comprises the above-mentioned additives, the carboxylic acid-modified nitrile-based copolymer latex component not containing the additive may be added to the total content of the carboxylic acid-modified nitrile- And can be 80% by weight to 99% by weight, 85% by weight to 98% by weight, or 88% by weight to 97% by weight. Within this range, the mechanical properties, durability and chemical resistance of the dip-

According to an embodiment of the present invention, the carboxylic acid-modified nitrile-based copolymer latex, that is, the carboxylic acid-modified nitrile-based copolymer latex composition containing the additive has a solid concentration of 5 wt% to 40 wt%, 8 wt% To 35% by weight, or from 10% by weight to 33% by weight, and the pH may be 7.0 to 12.0, 7.5 to 11.5, or 8 to 11. Within this range, have.

According to the present invention, there is provided a molded article comprising the layer derived from the carboxylic acid-modified nitrile-based copolymer latex. The molded product may be a dip-formed product prepared by dip-molding the carboxylic acid-modified nitrile-based copolymer latex and may include a layer derived from a carboxylic acid-modified nitrile-based copolymer latex formed from a carboxylic acid-modified nitrile-based copolymer latex by dip molding Or the like. The method for producing a molded article for molding the molded article may include a step of immersing the carboxylic acid modified nitrile-based copolymer latex by a direct dipping method, an anode adhesion dipping method, a Teague adhesion dipping method, or the like, As a specific example, it can be carried out by anodic adhesion dipping, and in this case, there is an advantage that a dip-shaped article having a uniform thickness can be obtained.

As a concrete example, the method for manufacturing a molded article may include a step (S100) of attaching a coagulant to a dip forming mold; A step (S200) of immersing the dip-molding die with the coagulant attached thereto in a carboxylic acid-modified nitrile-based copolymer latex to form a layer derived from a carboxylic acid-modified nitrile-based copolymer latex, that is, a dip molding layer; And a step (S300) of self-crosslinking the carboxylic acid-modified nitrile-based copolymer latex by heating the dip-formed layer.

The step (S100) comprises immersing a dip forming mold in a coagulating agent solution so as to form a coagulant in a dip forming mold, and attaching a coagulant to the surface of the dip forming mold, wherein the coagulant solution contains water, an alcohol or a mixture thereof As a dissolved solution, the content of the coagulant in the coagulant solution may be from 5% by weight to 50% by weight, or from 10% by weight to 40% by weight, based on the total amount 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; Acetic acid salts such as barium acetate, calcium acetate and zinc acetate; And sulfates such as calcium sulfate, magnesium sulfate and aluminum sulfate, and specific examples thereof may be calcium chloride or calcium nitrate.

In the step (S200), a dip molding frame having a coagulant attached thereto is immersed in the carboxylic acid modified nitrile-based copolymer latex of the present invention to form a dip molding layer, and a dip molding layer is formed in the dip molding frame Step.

The step (S300) may be a step of heating the dip molding layer formed in the dip forming mold to evaporate the liquid component to crosslink the carboxylic acid denatured nitrile-based copolymer latex to obtain a deep molded product have. In this case, when the carboxylic acid-modified nitrile-based copolymer latex according to the present invention is used, the carbonyl group of the carbonyl group-containing acrylic monomer-containing repeating unit of the carboxylic acid-modified nitrile-based copolymer contained in the carboxylic acid- The autocrosslinking reaction between hydrazide of the di-hydrazide of the dicarboxylic acid can be carried out so that there is no problem such as the allergic reaction caused by the sulfur and the vulcanization accelerator.

According to one embodiment of the present invention, the molded article can be a glove such as a surgical glove, an inspection 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 with reference to Examples. It is to be understood, however, that the following examples are illustrative of the present invention and that various changes and modifications can be made within the scope and spirit of the present invention, which are obvious to those of ordinary skill in the art and do not limit the scope of the present invention.

Example

Example 1

<Production of Carboxylic Acid Modified Nitrile Copolymer Latex>

A 10 L high-pressure polymerization reactor equipped with a stirrer, a thermometer, a condenser, an inlet of a nitrogen gas, and an inlet for continuously feeding monomers, an emulsifier and a polymerization initiator was purged with nitrogen, and 29 parts by weight of acrylonitrile, 65 parts by weight of 3-butadiene, 5 parts by weight of methacrylic acid, 3 parts by weight of sodium alkylbenzenesulfonate, 0.5 part by weight of t-dodecyl mercaptan and 140 parts by weight of ion-exchanged water were charged and heated to 38 占 폚. After the temperature was elevated, 0.3 parts by weight of potassium persulfate as a polymerization initiator was added to initiate polymerization. When the polymerization conversion was 62%, 1 part by weight of diacetone acrylamide was added. Thereafter, when the polymerization conversion reached 95%, 0.1 part by weight of sodium dimethyldithiocarbamate was added to terminate the polymerization. Next, unreacted monomers were removed through a deodorization process, ammonia water, an antioxidant and an antifoaming agent were added. After confirming that the pH of the latex was 7.2, 1 part by weight of adipic acid dihydrazide was added and mixed To obtain a carboxylic acid-modified nitrile-based copolymer latex having a solid concentration of 45% by weight and a pH of 8.5.

A potassium hydroxide solution and a second distilled water at a concentration of 3% by weight were added to 100 parts by weight (based on solid content) of the carboxylic acid-modified nitrile-based copolymer latex obtained above to prepare a carboxylic acid-modified nitrile-based copolymer having a solid concentration of 15% A latex was obtained.

<Production of Dip Molded Parts>

13 parts by weight of calcium nitrate, 82.5 parts by weight of water and 0.5 part by weight of a wetting agent (Teric 320, Huntsman Corporation, Australia) were mixed to prepare a coagulant solution. A hand-shaped ceramic mold was immersed in the prepared coagulant solution for 1 minute, and then taken out and dried at 100 ° C for 4 minutes to apply a coagulant to the hand mold.

Thereafter, the mold coated with the coagulant was immersed in the obtained carboxylic acid modified nitrile-based copolymer latex for 1 minute, taken out, dried at 130 캜 for 4 minutes, immersed in water for 3 minutes, leached, Dried at 130 DEG C for 3 minutes, and then crosslinked at 130 DEG C for 20 minutes. The crosslinked dip molding layer was peeled off from the hand mold to obtain a glove-shaped dip molded article.

Example 2

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, acrylonitrile was added in an amount of 29.9 parts by weight instead of 29 parts by weight, and diacetone acrylamide was added in an amount of 0.1 part by weight at a polymerization conversion of 65% Ammonia water, an antioxidant and a defoaming agent, and then adding 0.1 part by weight of adipic acid dihydrazide under the condition that the pH of the latex was 7.5, the same procedure as in Example 1 was carried out.

Example 3

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, 28 parts by weight of acrylonitrile was used instead of 29 parts by weight, diacetone acrylamide was added in an amount of 2 parts by weight at a polymerization conversion of 61% Ammonia water, an antioxidant and a defoamer, and then adding 2 parts by weight of adipic acid dihydrazide under the condition that the pH of the latex was 7.2.

Example 4

The procedure of Example 1 was repeated, except that diacetone acrylamide was added in an amount of 1 part by weight at a polymerization conversion of 80% at the time of preparing the carboxylic acid-modified nitrile-based copolymer latex in Example 1.

Example 5

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, diacetone acrylamide was added in an amount of 1 part by weight at a polymerization conversion of 67%, ammonia water, an antioxidant and a defoaming agent were added, Was 7.3, and adipic acid dihydrazide was added in an amount of 0.5 part by weight.

Example 6

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, acrylonitrile was added in an amount of 29.5 parts by weight instead of 29 parts by weight, and diacetone acrylamide was added in an amount of 0.5 part by weight at a polymerization conversion of 61% Ammonia water, an antioxidant and a defoaming agent, and then adding 1 part by weight of adipic acid dihydrazide under the condition that the pH of the latex was 7.6.

Example 7

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, diacetone acrylamide was added in an amount of 1 part by weight at a polymerization conversion of 63%, ammonia water, an antioxidant and a defoaming agent were added, Was 8.5 and adipic acid dihydrazide was added in an amount of 1 part by weight.

Comparative Example 1

The procedure of Example 1 was repeated, except that adipic acid dihydrazide was not added to the carboxylic acid-modified nitrile-based copolymer latex in Example 1.

Comparative Example 2

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, acrylonitrile was added in an amount of 30 parts by weight instead of 29 parts by weight, and ammonia water, an antioxidant and an antifoaming agent were added after the addition of diacetone acrylamide , And 1 part by weight of adipic acid dihydrazide was added in a state where the pH of the latex was 7.3.

Comparative Example 3

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, acrylonitrile was added in an amount of 30 parts by weight instead of 29 parts by weight, and diacetone acrylamide and adipic acid dihydrazide were not added Was carried out in the same manner as in Example 1 above.

Comparative Example 4

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, 27 parts by weight of acrylonitrile was added instead of 29 parts by weight, and diacetone acrylamide was added in an amount of 3 parts by weight at a polymerization conversion of 62% Ammonia water, an antioxidant and a defoaming agent, and then adding 3 parts by weight of adipic acid dihydrazide under the condition that the pH of the latex was 7.1.

Comparative Example 5

In Example 1, diacetone acrylamide was added at a polymerization conversion rate of 62%, not before the initiation of polymerization, with 29 parts by weight of acrylonitrile, 65 parts by weight of 1,3-butadiene and 5 parts by weight of methacrylic acid The results are shown in Table 1.

Comparative Example 6

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, diacetone acrylamide was added in an amount of 1 part by weight at a polymerization conversion of 40%, ammonia water, an antioxidant and a defoaming agent were added, Was 7.0 and adipic acid dihydrazide was added in an amount of 1 part by weight.

Comparative Example 7

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, diacetone acrylamide was added in an amount of 1 part by weight at a polymerization conversion rate of 61%, ammonia water, an antioxidant and a defoaming agent were added, Was 6.5, and adipic acid dihydrazide was added in an amount of 1 part by weight.

Comparative Example 8

In the preparation of the carboxylic acid-modified nitrile-based copolymer latex in Example 1, diacetone acrylamide was added in an amount of 1 part by weight at a polymerization conversion of 65%, ammonia water, an antioxidant and a defoaming agent were added, Was 4.5 and adipic acid dihydrazide was added in an amount of 1 part by weight.

Experimental Example

In order to compare the physical properties of the respective dip-molded articles produced in Examples 1 to 7 and Comparative Examples 1 to 8, stickiness, durability and chemical resistance were measured, and the contents of the carbonyl group-containing acrylic monomer and the amounts Point, the content of dicarboxylic acid dihydrazide feed and the pH of the latex at the time of addition Respectively.

* Stickiness: The sticky feeling felt on the hand when the dip molded article was peeled off from the hand mold was divided into ten points by touch feeling. 10 points for easily peeled off from deep molds, and 1 point for peeled off from deep molds because stickiness is the least.

* Durability: The S-shaped specimen was immersed in the artificial sweat solution, and the number of times the specimen was broken was measured by stretching 200% of the initial length at a rate of once per 2 seconds. The higher the number, the better the durability.

* Chemical resistance: Each of the molded articles prepared in the above Examples and Comparative Examples was used to prepare test pieces according to EN374-3: 2003. Each test specimen was placed in a test vessel of 51 mm in diameter and 35 mm in depth containing hexane, the substance to be tested for chemical resistance, and the time taken for hexane to permeate the specimen at a rate of 1 μg / cm ² / min Respectively. The longer the time, the better the chemical resistance.

division Example One 2 3 4 5 6 7 Charged amount (parts by weight) of carbonyl group-containing acrylic monomer One 0.1 2 One One 0.5 One (%, Polymerization conversion rate) of the carbonyl group-containing acrylic monomer 62 65 61 80 67 61 63 Dicarboxylic acid dihydrazide feed content (parts by weight) One 0.1 2 One 0.5 One One Latex pH when dicarboxylic acid dihydrazide is added 7.2 7.5 7.2 7.2 7.3 7.6 8.5 Stickiness (10-point method) 9 6 10 10 9 8 10 Durability (times) 310 180 335 289 295 207 310 Chemical resistance (minute) 18 11 20 19 16 12 19

division Comparative Example One 2 3 4 5 6 7 8 Charged amount (parts by weight) of carbonyl group-containing acrylic monomer One 0 0 3 One One One One (%, Polymerization conversion rate) of the carbonyl group-containing acrylic monomer 62 - - 62 0 40 61 65 Dicarboxylic acid dihydrazide feed content (parts by weight) 0 One 0 3 One One One One Latex pH when dicarboxylic acid dihydrazide is added - 7.3 - 7.1 7.2 7.0 6.5 4.5 Stickiness (10-point method) 3 2 2 8 5 5 3 2 Durability (times) 98 87 101 50 85 108 81 98 Chemical resistance (minute) 7 6 5 10 20 18 18 7

As shown in Tables 1 and 2, in the case of the dip-molded article using the carboxylic acid-modified nitrile-based copolymer latex prepared according to the present invention, the amount of the carbonyl group-containing acrylic monocerebellum and the dicarboxylic acid dihydrazide It was confirmed that stickiness, durability and chemical resistance were significantly improved as compared with Comparative Example 3.

On the other hand, in Comparative Example 1 in which only the carbonyl group-containing acrylic monomer was added and in Comparative Example 2 in which only the dicarboxylic acid dihydrazide was added, it was confirmed that the effect of improving stickiness, durability and chemical resistance was extremely small.

In addition, it was confirmed that the durability of Comparative Example 4 in which an excess amount of the carbonyl group-containing acrylic monomer and the dicarboxylic acid dihydrazide was added was lowered, and the carbonyl group-containing acrylic monomer was simultaneously It was confirmed that the effect of improving stickiness and durability was insignificant even in the case of Comparative Example 5 which was added and Comparative Example 6 which was added at the time of polymerization conversion of 40% even during the polymerization. This is because the degree of exposure of the carbonyl group on the repeating unit derived from an acrylic monomer containing a carbonyl group is reduced during self crosslinking and the crosslinking ability is lowered.

In addition, in Comparative Example 7 in which dicarboxylic acid dihydrazide was added in a pH of 6.5, and Comparative Example 8 in which the pH was 4.5, stickiness, durability, and chemical resistance were all poor This is attributable to the fact that, after the introduction of the dicarboxylic acid dihydrazide, the curing rapidly proceeded, the self-crosslinking was not smoothly performed, and the crosslinking ability was degraded.

The present inventors have found that when the carboxylic acid modified nitrile-based copolymer latex is produced according to the present invention and the dip molded article is molded using the same, the stickiness of the dip molded article can be improved without using sulfur and vulcanization accelerator And it was confirmed that it is excellent in durability and chemical resistance.

Claims (10)

(S10) polymerizing a conjugated diene monomer, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid monomer;
A step (S20) of charging and polymerizing a carbonyl group-containing acrylic monomer at a polymerization conversion rate of 60% or more during the polymerization in the step (S10); And
(S30) of adding a dicarboxylic acid dihydrazide to the carboxylic acid modified nitrile-based copolymer latex having a pH of 7.0 or more after the completion of the polymerization in the step (S20)
The content of the carbonyl group-containing acrylic monomer added in the step (S20) is more than 0 wt% to less than 3 wt% with respect to the total amount of the monomer mixture,
Wherein the content of the dicarboxylic acid dihydrazide to be added in the step (S30) is more than 0 parts by weight and less than 3 parts by weight based on 100 parts by weight of the total monomer mixture. The method according to claim 1,
Wherein the carbonyl group-containing acrylic monomer charged in step (S20) is diacetone acrylamide. The method according to claim 1,
Wherein the carbonyl group-containing acrylic monomer charged in the step (S20) is introduced at a polymerization conversion rate of 61% to 80%. The method according to claim 1,
Wherein the content of the carbonyl group-containing acrylic monomer added in the step (S20) is 0.1 wt% to 2 wt% with respect to the total amount of the monomer mixture. The method according to claim 1,
Wherein the dicarboxylic acid dihydrazide to be added in the step (S30) is adipic acid dihydrazide. The method according to claim 1,
Wherein the dicarboxylic acid dihydrazide is introduced onto the carboxylic acid-modified nitrile-based copolymer latex having a pH of 7.2 to 8.5 in the step (S30). The method according to claim 1,
Wherein the content of the dicarboxylic acid dihydrazide is 0.1 part by weight to 2 parts by weight based on 100 parts by weight of the total monomer mixture in the step (S30). A carboxylic acid-modified nitrile-based copolymer comprising a repeating unit derived from a conjugated diene monomer, a repeating unit derived from an ethylenically unsaturated nitrile monomer, a repeating unit derived from an ethylenically unsaturated acid monomer, and a repeating unit derived from an acrylic monomer containing a carbonyl group; And dicarboxylic acid dihydrazide,
All or a part of the carbonyl group-containing acrylic monomer-derived repeating units are distributed on the surface of the carboxylic acid-modified nitrile-based copolymer latex,
The content of the repeating unit derived from an acrylic monomer containing a carbonyl group is more than 0 wt% to less than 3 wt% with respect to the total amount of repeating units derived from each monomer,
The content of the dicarboxylic acid dihydrazide is more than 0 parts by weight to less than 3 parts by weight based on 100 parts by weight of the total amount of each monomer-derived repeating unit. A molded article comprising the latex-derived layer of a carboxylic acid-modified nitrile-based copolymer according to claim 8. 10. The method of claim 9,
The molded article may be a glove, a condom, a catheter, or a health care article.