Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/02—Direct processing of dispersions, e.g. latex, to articles
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
  • C08K5/37—Thiols
  • C08K5/378—Thiols containing heterocyclic rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F236/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F236/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F236/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
  • C08F236/14—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen
  • C08F236/16—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen containing halogen
  • C08F236/18—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen containing halogen containing chlorine
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0091—Complexes with metal-heteroatom-bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2311/00—Characterised by the use of homopolymers or copolymers of chloroprene
  • C08J2311/02—Latex
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2411/00—Characterised by the use of homopolymers or copolymers of chloroprene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
  • C08K2003/2296—Oxides; Hydroxides of metals of zinc
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/019—Specific properties of additives the composition being defined by the absence of a certain additive

Definitions

• the present invention relates to a chloroprene-based polymer latex composition and its dip-molded product. More particularly, it relates to a chloroprene-based polymer latex composition containing chloroprene and a dip-molded article obtained using the composition.
• Chloroprene-based polymers are known as materials for dip-molded products such as medical surgical gloves, medical examination gloves, industrial gloves, balloons, catheters, and rubber boots.
• Patent Document 1 describes that damping performance is improved by mixing a low-molecular-weight chloroprene polymer having a number average molecular weight in the range of 500 to 50,000 with respect to anti-vibration rubber applications.
• Patent Document 2 regarding the use of dip-molded products, 100 parts by mass of modified polychloroprene obtained by copolymerizing chloroprene and methacrylic acid, 90 to 150 parts by mass of water, 1 to 5 parts by mass of an emulsifier, and 0 parts by mass of potassium ion A polychloroprene latex of pH 7-14 is described containing 0.5-2.5 parts by weight.
• Patent Document 3 relates to dip molding product application, copolymerizing chloroprene and 2,3-dichloro-1,3-butadiene, polychloroprene 13C-solid NMR spectrum, peak area of 126.2 ⁇ 127.6ppm (A), a peak area (B) of 122.0 to 126.2 ppm, and a peak area (C) of 129.9 to 130.3 ppm are in the range represented by the following general formula (I).
• Mercaptan-modified polychloroprene latex Are listed.
• Patent Document 4 describes a chloroprene polymer latex that can achieve both excellent flexibility and mechanical properties in a vulcanized rubber produced by dip molding by containing high and low molecular weight substances for use in dip-molded products. It is
• Dip-molded products of chloroprene-based polymers tend to require high flexibility, as is the case with dip-molded products obtained using natural rubber or polyisoprene.
• a chloroprene-based polymer latex composition with improved physical properties is desired.
• vulcanization accelerators such as thiuram, dithiocarbamate, thiourea, guanidine, xanthate, and thiazole, which are preferred for improving mechanical strength, are classified as type IV allergens and are considered sanitary.
• a main object of the present invention is to provide a chloroprene-based polymer latex composition capable of obtaining a chloroprene-based polymer dip-molded article having high breaking strength while maintaining high strength.
• the present invention provides a chloroprene-based polymer latex composition
• a chloroprene-based polymer latex composition comprising a chloroprene-based polymer latex, a metal oxide, and a heteroaromatic compound
• the chloroprene-based polymer latex composition comprises the chloroprene-based polymer
• the chloroprene-based polymer latex containing 0.5 to 15.0 parts by mass of the metal oxide and 0.1 to 10.0 parts by mass of the heteroaromatic compound based on 100 parts by mass of the solid content of the latex.
• the content of the alkyl mercaptan compound is 0.34 parts by mass or less with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex, and the heteroaromatic compound is represented by the chemical formula (1).
• a chloroprene-based polymer latex composition a chloroprene-based polymer latex composition.
• X in the chemical formula (1) represents a hydrogen atom or a metal atom.
• R 1 to R 4 each represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted ether group, a nitro group, an amino group, or a carboxyl group, and R 1 to R 4 may be the same or different.
• the content of the alkylmercaptan compound is 0.34 parts by mass or less with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex
• the heteroaromatic compound is represented by the chemical formula (1), a chloroprene-based A polymer latex composition.
• X in the chemical formula (1) represents a hydrogen atom or a metal atom.
• R 1 to R 4 each represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted ether group, represents a nitro group, an amino group, or a carboxyl group.R 1 to R 4 may be the same or different.
• [2] The chloroprene-based polymer latex composition according to [1], which contains 0.5 to 10.0 parts by mass of an antioxidant with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex.
• the chloroprene-based polymer latex contains at least one of a chloroprene homopolymer and a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, and In the molecular weight distribution obtained by gel permeation chromatography measurement of the sol soluble in tetrahydrofuran, the first peak having a weight average molecular weight of 500,000 or more and the weight average molecular weight of 7,000 to 80,000
• a coalesced latex composition [5]
• the chloroprene-based polymer rubber obtained by freeze-drying the chloroprene-based polymer latex is cut, placed in a flask attached to a condenser, and extracted with an ethanol/toluene azeotrope specified in JIS K6229.
• the total amount b of abietic acid, neoabietic acid, parastric acid, levopimaric acid and their salts relative to the total amount a of dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid and their salts in the components measured by gas chromatography The chloroprene-based polymer latex composition according to any one of [1] to [4], wherein the mass ratio b/a of is 0.10 or more.
• JIS Japanese Industrial Standards
• the content of the alkyl mercaptan compound in the chloroprene-based polymer latex composition is a specific amount or less, and the chloroprene-based polymer latex composition contains a heteroaromatic compound and a metal compound in a specific amount.
• the content of alkyl mercaptan compounds which is a concern for hygiene, is low, and extremely excellent flexibility can be achieved even if the amount of vulcanization accelerator or sulfur added is reduced or not.
• a chloroprene-based polymer latex composition capable of obtaining a chloroprene-based polymer dip-molded article having high breaking strength while having a chloroprene-based polymer latex composition.
• Chloroprene-Based Polymer Latex Composition First, the chloroprene-based polymer latex composition according to the first embodiment of the present invention will be described.
• the chloroprene-based polymer described in the present embodiment is a polymer containing monomer units derived from 2-chloro-1,3-butadiene (hereinafter also referred to as chloroprene). is. Further, the chloroprene-based polymer according to one embodiment of the present invention can also be a copolymer of chloroprene and other monomers copolymerizable with chloroprene.
• chloroprene-based polymer according to one embodiment of the present invention can also contain no sulfur, and the chloroprene-based polymer according to one embodiment of the present invention has -S-S resulting from sulfur in the main chain. - can also be without structure.
• the chloroprene-based polymer according to one embodiment of the present invention may be obtained by mixing two or more different chloroprene-based polymers.
• Chloroprene-based polymers include homopolymers of chloroprene (2-chloro-1,3-butadiene), copolymers of chloroprene and 1-chloro-1,3-butadiene, chloroprene and 2,3-dichloro-1, Containing at least one selected from the group consisting of copolymers with 3-butadiene and copolymers of chloroprene, 1-chloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene is preferred, and at least one selected from homopolymers of chloroprene and copolymers of chloroprene and 2,3-dichloro-1,3-butadiene is more preferred.
• the chloroprene-based polymer according to one embodiment of the present invention contains 50 to 100% by mass of monomer units derived from chloroprene when the chloroprene-based polymer contained in the chloroprene-based polymer latex composition is taken as 100% by mass. It can contain 90 to 100% by mass, preferably.
• the content of monomeric units derived from chloroprene is, for example, , 100% by weight, and may be within a range between any two of the numerical values exemplified herein.
• the chloroprene-based polymer according to one embodiment of the present invention is derived from 2,3-dichloro-1,3-butadiene when the chloroprene-based polymer contained in the chloroprene-based polymer latex composition is taken as 100% by mass. It can contain 0 to 30% by mass of monomer units.
• the content of monomer units derived from 2,3-dichloro-1,3-butadiene is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 , 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30% by mass, and any of the numerical values exemplified here 2 It may be within a range between two.
• the chloroprene-based polymer according to one embodiment of the present invention may contain monomer units derived from chloroprene and monomer units derived from 2,3-dichloro-1,3-butadiene.
• the chloroprene-based polymer contains 100% by mass of the total of the monomer units derived from chloroprene and the monomer units derived from 2,3-dichloro-1,3-butadiene contained in the chloroprene-based polymer. Then, it preferably contains 0 to 30% by mass, more preferably 5 to 25% by mass, of monomer units derived from 2,3-dichloro-1,3-butadiene.
• each monomer unit refers to all chloroprene-based polymers contained in the chloroprene-based polymer latex composition. means the sum of each monomeric unit in
• the chloroprene-based polymer according to one embodiment of the present invention is a sulfur-modified chloroprene-based
• the polymer content is preferably 20% by mass or less.
• the content of the sulfur-modified chloroprene polymer is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 , 19, 20% by weight, and may be within a range between any two of the numerical values exemplified herein.
• a chloroprene-based polymer according to an embodiment of the present invention may not contain a sulfur-modified chloroprene-based polymer.
• the chloroprene-based polymer latex according to one embodiment of the present invention can be obtained by dispersing a chloroprene-based polymer in water.
• a chloroprene-based polymer in water.
• At least one selected from the group consisting of copolymers with 1,3-butadiene is dispersed in water, and a homopolymer of chloroprene, or chloroprene and 2,3-dichloro-1, A copolymer with 3-butadiene may be dispersed in water.
• Alkyl Mercaptans Compound Contained in Chloroprene-based Polymer Latex Composition
• the content is 0.34 parts by mass or less.
• the content of the alkyl mercaptan compound is, for example, 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0 .10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22 , 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34 parts by mass and may be in a range between any two of the numerical values exemplified here.
• the content of alkyl mercaptan compounds in the chloroprene-based polymer latex composition can be measured using gas chromatography.
• the analysis target can be a chloroprene-based polymer latex or composition.
• a solvent such as THF or A standard addition method may be applied.
• Measurement conditions for gas chromatography can be as shown in Examples.
• the alkyl mercaptan compounds are not particularly limited, but examples include long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan.
• long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan.
• Alkyl mercaptan compounds are usually used as chain transfer agents to obtain the chloroprene-based polymer contained in the chloroprene-based polymer latex composition.
• the content of the alkyl mercaptan compound contained in the chloroprene-based polymer latex composition can be adjusted by adjusting the charging amount and the polymerization conversion rate as a chain transfer agent in the polymerization process for obtaining the chloroprene-based polymer and the chloroprene-based polymer latex. can be controlled by
• a monomer such as a chloroprene monomer or 2,3-dichloro-1,3-butadiene is added in portions during the polymerization reaction to adjust the charging amount of the chain transfer agent. can also
• the chloroprene-based polymer latex according to one embodiment of the present invention has a tetrahydrofuran-soluble sol content in the chloroprene-based polymer latex measured by gel permeation chromatography.
• the molecular weight distribution obtained by the above can have a first peak with a weight average molecular weight of 400,000 or more.
• the first peak preferably has a weight average molecular weight of 500,000 or more.
• the obtained dip-molded article can have better breaking strength.
• the weight average molecular weight of the first peak in the molecular weight distribution can be 500,000 or more, or may be 600,000 or more, from the viewpoint of easily obtaining excellent breaking strength.
• the weight average molecular weight of the first peak is, for example, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 750,000, 800,000, 850,000 , 900,000, 950,000, 1,000,000, and may be in the range between any two of the numbers exemplified herein.
• the chloroprene-based polymer latex according to one embodiment of the present invention can have a second peak with a weight average molecular weight of 7,000 to 120,000 in the molecular weight distribution, and the second peak has a weight average molecular weight of is preferably 7,000 to 80,000.
• the weight average molecular weight of the second peak when the weight average molecular weight of the second peak is at least the above lower limit, more excellent breaking strength can be obtained.
• the weight-average molecular weight of the second peak may be 10,000 or more, or 15,000 or more from the viewpoint of easily obtaining a dip-molded body.
• the weight average molecular weight of the second peak is equal to or less than the above upper limit, better flexibility can be obtained.
• the weight average molecular weight of the second peak of the chloroprene-based polymer is 80,000 or less, 70,000 or less, 50,000 or less, or 30,000 or less from the viewpoint of easily obtaining even better flexibility. good.
• the weight average molecular weight of the second peak is, for example, 7,000, 8,000, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000 , 17,000, 18,000, 19,000, 20,000, 21,000, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29 , 000, 30,000, 35,000, 40,000, 50,000, 60,000, 70,000, 80,000, 100,000, 120,000, any two of the numerical values exemplified here It may be within a range between two.
• the chloroprene-based polymer latex according to one embodiment of the present invention preferably has a first peak and a second peak in the molecular weight distribution.
• chloroprene-based polymer latex According to the chloroprene-based polymer latex according to one embodiment of the present invention, it is possible to obtain a dip-molded article having even better flexibility and breaking strength due to the above molecular weight distribution.
• the molecular weight distribution of the sol soluble in tetrahydrofuran in the chloroprene-based polymer latex can be obtained by weight average molecular weight measurement by gel permeation chromatography.
• the chloroprene-based polymer latex is dissolved in tetrahydrofuran, and the eluted portion (sol portion) is analyzed by gel permeation chromatography (GPC). GPC measurement conditions can be as described in Examples.
• GPC gel permeation chromatography
• a chloroprene-based polymer latex composition was analyzed, and the chloroprene-based polymer latex composition was dissolved in tetrahydrofuran and analyzed in the same manner. It is also possible to determine the molecular weight distribution of the tetrahydrofuran-soluble sol in the polymer latex.
• a chloroprene-based polymer latex in which the first peak and the second peak are detected in the molecular weight distribution may be obtained.
• the weight average molecular weight of each chloroprene-based polymer latex depends on the type and amount of the chain transfer agent in the polymerization of each chloroprene-based polymer latex, polymerization temperature, It can be controlled by adjusting the polymerization time, the polymerization conversion rate, and the like.
• the two or more types of chloroprene-based polymer latexes may be stirred and mixed using paddle blades at 100 rpm for 1 minute to obtain the chloroprene-based polymer latexes.
• the toluene-insoluble content (gel content) of the chloroprene-based polymer latex according to one embodiment of the present invention is 50 to 50% with respect to 100% by mass of the chloroprene-based polymer. 85% by mass, preferably 60 to 85% by mass.
• the toluene-insoluble content is, for example, 50, 55, 60, 65, 70, 75, 80, 85% by mass, and may be within a range between any two of the numerical values exemplified here. By setting the toluene-insoluble content within the above numerical range, more excellent breaking strength is exhibited. This numerical range can be adjusted by preparing two or more types of chloroprene-based polymer latexes having different toluene-insoluble contents and adjusting the mixing ratio of these.
• Toluene-insoluble matter is obtained by cutting 1 g of chloroprene-based polymer rubber obtained by freeze-drying chloroprene-based polymer latex into 2 mm squares, dissolving in toluene for 16 hours, centrifuging, and filtering using a 200-mesh wire mesh. It is obtained by separating the insoluble matter and measuring the dried weight.
• the toluene-insoluble matter can be obtained from the following formula.
• the chloroprene-based polymer latex according to one embodiment of the present invention is obtained by cutting a chloroprene-based polymer rubber obtained by freeze-drying the chloroprene-based polymer latex, putting it in a flask attached to a condenser, and adding ethanol specified in JIS K 6229.
• the mass ratio b/a of the total amount b of parastric acid, levopimaric acid and salts thereof is preferably 0.10 or more.
• the above b/a is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.0. 1, 1.2, and may be in the range between any two of the numbers exemplified herein.
• the mass ratio b/a is 0.10 or more, higher breaking strength is exhibited, and more preferably when the mass ratio b/a is in the range of 0.3 to 1.2, high breaking strength and excellent A flexible dip-molded body is obtained.
• the chloroprene-based polymer rubber which is a dried product obtained by freeze-drying the chloroprene-based polymer latex, it is placed in a flask attached to a condenser, and ethanol specified in JIS K 6229 is added.
• gas chromatograph-mass spectrometry measurements can be performed.
• the measurement conditions for gas chromatography mass spectrometry can be as described in Examples.
• the value obtained by dividing the peak area value of the peak corresponding to each resin acid component by the total peak area value detected by gas chromatography-mass spectrometry can be regarded as the content.
• the total amount a, the total amount b and the mass ratio b/a can be obtained from the peak area of each resin acid.
• a chloroprene-based polymer latex composition was analyzed, and a dried product obtained by freezing the chloroprene-based polymer latex composition was analyzed in the same manner. It is also possible to obtain the mass ratio b/a in the chloroprene-based polymer latex contained.
• the value of the mass ratio b/a can be controlled by adjusting the types of rosin acid and rosin salt added as emulsifiers and their compounding ratio.
• a method for producing a chloroprene-based polymer latex according to one embodiment of the present invention can include a polymerization step of polymerizing a monomer containing chloroprene to obtain a chloroprene-based polymer latex. Moreover, the method for producing a chloroprene-based polymer latex according to one embodiment of the present invention can further include a mixing step of mixing two or more types of chloroprene-based polymer latexes having different weight average molecular weights.
• the monomer contains chloroprene and can also contain other monomers copolymerizable with chloroprene.
• Other monomers copolymerizable with chloroprene include 1-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, isoprene, styrene, methacrylic acid, acrylonitrile, sulfur, and the like. can be done.
• Monomers can also include chloroprene and 2,3-dichloro-1,3-butadiene.
• each monomer to be charged are preferably adjusted so that each monomer in the resulting polymer is within the above numerical range.
• the copolymerization amount of 2,3-dichloro-1,3-butadiene in the chloroprene polymer contained in the chloroprene polymer latex is the chloroprene monomer contained in the chloroprene polymer and 2,3-dichloro It can also be in the range of 0 to 30% by mass with respect to 100% by mass in total with -1,3-butadiene. is preferably in the range of 0 to 30 parts by weight per 100 parts by weight of the total of the chloroprene monomer and the 2,3-dichloro-1,3-butadiene monomer.
• the charged amount of 2,3-dichloro-1,3-butadiene is adjusted to a total of 100 parts by mass of the chloroprene monomer and the 2,3-dichloro-1,3-butadiene monomer. , more preferably 5 to 25 parts by mass.
• raw material monomers are polymerized by polymerization methods such as emulsion polymerization, solution polymerization, suspension polymerization, and bulk polymerization.
• polymerization methods such as emulsion polymerization, solution polymerization, suspension polymerization, and bulk polymerization.
• emulsion polymerization is preferable because of various advantages such as easy control, easy removal of the polymer from the polymerization-terminated liquid, and relatively high polymerization rate.
• Emulsion polymerization is a kind of radical polymerization, and raw material monomers are mixed with a chain transfer agent, water, an alkali (e.g., metal hydroxide such as potassium hydroxide and sodium hydroxide), an emulsifier (dispersant), a reducing agent. (for example, sodium hydrogen sulfite), a polymerization initiator, etc., are put into a reactor and polymerized.
• a chain transfer agent water
• an alkali e.g., metal hydroxide such as potassium hydroxide and sodium hydroxide
• an emulsifier disersant
• a reducing agent for example, sodium hydrogen sulfite
• a polymerization initiator etc.
• the type of chain transfer agent used in emulsion polymerization is not particularly limited, and examples thereof include long-chain alkylmercaptans such as n-dodecylmercaptan and tert-dodecylmercaptan, and dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide. , iodoform, etc., known chain transfer agents commonly used in the emulsion polymerization of chloroprene can be used.
• the chain transfer agent long-chain alkylmercaptans are preferred, and n-dodecylmercaptan is more preferred.
• the weight average molecular weight of the obtained chloroprene-based polymer latex can be adjusted.
• the charged amount of the chain transfer agent before the initiation of emulsion polymerization is adjusted to the monomer It is preferably 0.01 part by mass or more per 100 parts by mass (for example, 100 parts by mass of chloroprene and 2,3-dichloro-1,3-butadiene in total).
• the amount of the chain transfer agent charged is more preferably 0.02 to 0.05 parts by mass.
• the amount of the chain transfer agent, particularly long-chain alkyl mercaptans charged is 0.01 parts by mass or more, the storage stability of the latex is further improved, and the amount charged is less than 0.10 parts by mass, particularly 0.01 part by mass. If the amount is less than 0.5 parts by mass, the toluene-insoluble matter will increase, and the breaking strength of the resulting dip-molded article containing the chloroprene-based polymer latex will increase.
• the charged amount of the chain transfer agent before the initiation of emulsion polymerization is It is preferably 1.0 to 10.0 parts by mass with respect to 100 parts by mass of the polymer.
• the charged amount is, for example, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 parts by mass and may be in a range between any two of the numerical values exemplified here.
• emulsifiers include anionic emulsifiers and nonionic emulsifiers.
• anionic emulsifiers include fatty acid salts such as tallow fatty acid potassium, partially hydrogenated tallow fatty acid potassium, potassium oleate and sodium oleate; resinates; alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate; sodium salts of ⁇ -naphthalenesulfonic acid formalin condensates;
• nonionic emulsifiers include polyethylene glycol ester emulsifiers and polyvinyl alcohol.
• anionic emulsifiers are preferred, resinates are preferred, rosin acids and rosin acids are preferred, and at least one selected from the group consisting of potassium rosinate and sodium rosinate is more preferred.
• resinates are preferred, rosin acids and rosin acids are preferred, and at least one selected from the group consisting of potassium rosinate and sodium rosinate is more preferred.
• emulsifiers can be used singly or in combination of two or more.
• the amount of the emulsifier used is preferably 1.0 to 6.5 parts by weight per 100 parts by weight of the monomer.
• the emulsifier used for emulsion polymerization is preferably a resinate, particularly rosin acids, and rosin acids contain components having a conjugated double bond structure, such as abietic acid, neoabietic acid, parastric acid, and levopimaric acid. It is preferred to use rosin acids and their metal salts. Breaking strength can be further improved by using rosin acids containing these resin acids.
• rosin acids are dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid and their salts contained in the chloroprene polymer latex, abietic acid, neoabietic acid, parastric acid, levopimaric acid and It is preferable to select the type and adjust the blending amount so that the mass ratio b/a of the total amount b of the salt of is 0.10 or more.
• rosin acids it is possible to prevent aggregation and pH fluctuation of rubber solids when blended with the base latex.
• emulsifiers include, for example, metal salt of aromatic sulfinic acid formalin condensate, sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, sodium alkyldiphenylethersulfonate, potassium alkyldiphenylethersulfonate, polyoxyethylene alkylethersulfonate. sodium, sodium polyoxypropylene alkyl ether sulfonate, potassium polyoxyethylene alkyl ether sulfonate, potassium polyoxypropylene alkyl ether ether sulfonate, and the like.
• the content of anionic surfactants other than rosin acid is preferably 0.2 to 1.0% by mass with respect to 100% by mass of the chloroprene-based polymer contained in the chloroprene-based polymer latex.
• the amount of the anionic surfactant excluding rosin acid to be charged before the initiation of emulsion polymerization is set to is preferably within the range of 0.2 to 0.9 parts by mass.
• the pH of the aqueous emulsion at the start of emulsion polymerization is preferably 10.5 to 13.5.
• the aqueous emulsion refers to a mixed solution of a chain transfer agent and monomers (chloroprene, 2,3-dichloro-1,3-butadiene, etc.) immediately before the start of emulsion polymerization. A case where the composition is changed by addition is also included.
• the pH of the aqueous emulsion at the start of emulsion polymerization is 10.5 or more, the polymerization reaction can be controlled more stably.
• the pH is 13.5 or less, an excessive increase in viscosity during polymerization is suppressed, and the polymerization reaction can be controlled more stably.
• the polymerization temperature for emulsion polymerization is preferably within the range of 5 to 55°C. When the temperature is 5°C or higher, the emulsion does not freeze, and when it is 55°C or lower, the chloroprene monomer does not evaporate or boil, which is preferable.
• potassium persulfate As the polymerization initiator, potassium persulfate, benzoyl peroxide, ammonium persulfate, hydrogen peroxide, etc., which are used in normal radical polymerization, can be used.
• the polymerization conversion rate is preferably in the range of 50-95%.
• the polymerization reaction is terminated by adding a polymerization terminator.
• the polymerization conversion rate is 50% or more, the toluene-insoluble matter tends to increase, and the strength of the obtained dip-molded coating tends to increase. It is also advantageous from the viewpoint of production cost. If the polymerization conversion rate is less than 95%, it is possible to avoid a decrease in polymerization reactivity due to a decrease in unreacted monomers and a decrease in productivity.
• polymerization terminators examples include diethylhydroxyamine, thiodiphenylamine, 4-tert-butylcatechol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol and the like. Unreacted monomers after completion of the emulsion polymerization can be removed by a conventional method such as distillation under reduced pressure.
• chloroprene-based polymer latex obtained by the production method of one embodiment of the present invention contains a freeze stabilizer, an emulsion stabilizer, a viscosity modifier, an antioxidant, Preservatives and the like can optionally be added.
• a method for producing a chloroprene-based polymer latex according to an embodiment of the present invention may further include a mixing step of mixing two or more types of chloroprene-based polymer latexes having different weight average molecular weights after the polymerization step. .
• a mixing step two or more chloroprene-based polymer latexes can be mixed by a known method.
• the chloroprene-based polymer latex may be obtained by stirring and mixing with a paddle blade at 30 to 300 rpm for 20 seconds to 3 minutes, for example, 100 rpm for 1 minute.
• the chloroprene-based polymer latex composition according to the present invention contains a metal oxide.
• Metal oxides contained in the chloroprene-based polymer latex composition are not particularly limited, and examples thereof include zinc oxide, lead oxide, trilead tetroxide, magnesium oxide, aluminum oxide iron oxide, beryllium oxide, and titanium oxide.
• the metal oxide preferably contains zinc oxide.
• Zinc oxide is generally considered to function as a scavenger for dechlorinated atoms in chloroprene-based polymers.
• these metal oxides may be used individually by 1 type, and may be used in mixture of 2 or more types.
• the amount of the metal oxide added is preferably 0.5 to 15.0 parts by mass with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex contained in the chloroprene-based polymer latex composition.
• the amount of the metal oxide added is 0.5 parts by mass or more, the breaking strength is expected to improve due to the cross-linking effect between the polymers.
• the amount of the metal oxide to be added is 15.0 parts by mass or less, it is possible to obtain an immersion-molded article having excellent flexibility. From the viewpoint of physical property balance between flexibility and breaking strength of the obtained dip-molded product, the amount of metal oxide added is more preferably 0.5 to 5.0 parts by mass.
• the chloroprene-based polymer latex composition according to the present invention contains a heteroaromatic ring-based compound.
• the heteroaromatic compound contained in the chloroprene-based polymer latex composition can be represented by chemical formula (1) and has a benzimidazole structure.
• a compound having this structure may be mainly used as a secondary anti-aging agent in compounding a rubber composition.
• X in the mercapto group represents a hydrogen atom or a metal atom.
• X may be a hydrogen atom and may have a thiol group.
• X can also be a metal atom, and examples of metal atoms include zinc, sodium, copper, nickel, and tellurium, with zinc being preferred.
• R 1 to R 4 in chemical formula (1) each represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted ether group, a nitro group, an amino group, or a carboxyl group.
• R 1 to R 4 may be the same or different.
• a heteroaromatic compound may be used individually by 1 type, and may be used in mixture of 2 or more types.
• Heteroaromatic compounds include, for example, 2-mercaptobenzimidazole, 5-methyl-2-mercaptobenzimidazole, 4-methyl-2-mercaptobenzimidazole, 5-methoxy-2-mercaptobenzimidazole, 4-methoxy-2-mercaptobenzimidazole. , 5-nitro-2-mercaptobenzimidazole, 5-amino-2-mercaptobenzimidazole, 5-carboxy-2-mercaptobenzimidazole, zinc salts of 2-mercaptobenzimidazole, and the like.
• 2-mercaptobenzimidazole 5-methyl-2-mercaptobenzimidazole, 4-methyl-2-mercaptobenzimidazole, 5-methoxy-2-mercaptobenzimidazole, 4-methoxy-2-mercaptobenzimidazole, 2-mercaptobenzimidazole is preferred.
• the amount of the heteroaromatic compound added is preferably 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the solid content of the chloroprene polymer latex contained in the chloroprene polymer latex composition.
• the amount of the heteroaromatic compound to be added is, for example, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0. 0, 7.0, 8.0, 9.0, 10.0 parts by mass, and may be within a range between any two of the numerical values exemplified here.
• the amount added is 0.2 parts by mass or more, the immersion-molded article obtained using this composition exhibits a very high breaking strength.
• the amount added is 10.0 parts by mass or less, the stability of the chloroprene-based polymer latex composition is ensured. From the viewpoint of the physical property balance between the flexibility and breaking strength of the obtained dip molded product, the amount added is more preferably 0.3 to 5.0 parts by mass.
• the chloroprene-based polymer latex composition according to the present invention may also contain an antioxidant.
• an antioxidant There are no particular restrictions on the antioxidant, and phenolic antioxidants, amine antioxidants, heat resistant oxidation (aging) inhibitors, ozone resistant antioxidants, and the like can be used.
• a phenol-based antioxidant can be used from the viewpoint of the color tone, texture, and sanitation of the dip-molded product.
• hindered phenol-based antioxidants have a strong effect.
• hindered phenolic antioxidants examples include 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'- butylidene (3-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), butylated reaction product of p-cresol and dicyclopentadiene, 2,5'-di-t -butylhydroquinone, 2,5'-di-t-amylhydroquinone.
• the butylated reaction product of p-cresol and dicyclopentadiene is desirable from the viewpoint of being generally dispersible in aqueous materials.
• these compounds may be used individually by 1 type, and may mix and use 2 or more types.
• the amount of the antioxidant added is preferably 0.5 to 10.0 parts by mass based on 100 parts by mass of the solid content of the chloroprene-based polymer latex contained in the chloroprene-based polymer latex composition.
• the amount of antioxidant added is, for example, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 parts by mass, and may be within a range between any two of the numerical values exemplified here.
• the amount of the antioxidant to be added is 0.5 parts by mass or more, it is possible to obtain the effect of suppressing the color tone change of the dip-molded product.
• the amount of the antioxidant to be added is 10.0 parts by mass or less, the stability of the chloroprene-based polymer latex composition is ensured. Further, from the viewpoint of physical property balance between flexibility and breaking strength of the dip-molded body obtained, the amount of the antioxidant to be added is more preferably 0.5 to 5.0 parts by mass.
• the chloroprene-based polymer latex composition according to one embodiment of the present invention may also contain a vulcanizing agent and/or a vulcanization accelerator. Further, the chloroprene-based polymer latex composition according to one embodiment of the present invention contains sulfur and the above-mentioned thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthate-based, thiazole-based vulcanization accelerators, etc.
• the chloroprene-based polymer latex composition molded article includes one containing a vulcanizing agent and not containing a vulcanization accelerator, one containing a vulcanizing accelerator but not containing a vulcanizing agent, and one containing a vulcanizing agent and a vulcanization accelerator. including those containing, and those not containing vulcanizing agents and vulcanization accelerators. Whether or not a vulcanizing agent and a vulcanization accelerator are blended may be determined according to the desired dip-molded product.
• vulcanizing agents include, but are not limited to, sulfur, zinc oxide, and magnesium oxide.
• the amount of the vulcanizing agent added can be 0 to 10.0 parts by mass with respect to 100 parts by mass of the solid content of the chloroprene-based polymer latex contained in the chloroprene-based polymer latex composition.
• the amount of the vulcanizing agent added is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by mass, and is within the range between any two of the numerical values exemplified here. may be
• the vulcanization accelerator acts with the vulcanizing agent to increase the vulcanization speed, shorten the vulcanization time, lower the vulcanization temperature, reduce the amount of vulcanizing agent, and improve the physical properties of the vulcanized rubber. It is an agent added for the purpose of, and usually refers to an agent that accelerates the sulfur vulcanization reaction.
• Vulcanization accelerators generally used for vulcanization of chloroprene-based polymer latex include thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthate-based, and thiazole-based accelerators. It is not limited. These are used alone or in combination of two or more as needed.
• Thiuram-based vulcanization accelerators include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide.
• Dithiocarbamate-based vulcanization accelerators include sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, and copper dimethyldithiocarbamate.
• ferric dimethyldithiocarbamate, tellurium diethyldithiocarbamate, etc., and zinc dibutyldithiocarbamate is particularly preferably used.
• Thiourea-based vulcanization accelerators include ethylenethiourea, N,N'-diethylthiourea, trimethylthiourea, and N,N'-diphenylthiourea.
• Guanidine-based vulcanization accelerators include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and dicatechol borate di-o-tolylguanidine salts. .
• xanthate-based vulcanization accelerators examples include zinc butylxanthate and zinc isopropylxanthate.
• Thiazole-based vulcanization accelerators include 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, 2-mercaptobenzothiazole zinc salt, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(4'- morpholinodithio)benzothiazole and the like.
• the amount of the vulcanization accelerator added can be 0 to 5.0 parts by mass with respect to 100 parts by mass of the solid content of the chloroprene polymer latex contained in the chloroprene polymer latex composition.
• the amount of vulcanization accelerator added is, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5 .0 and may be in the range between any two of the values exemplified herein.
• a chloroprene-based polymer latex composition molded article according to one embodiment of the present invention exhibits excellent mechanical properties regardless of the presence or absence of the addition of a vulcanizing agent and a vulcanization accelerator.
• the chloroprene-based polymer latex composition according to one embodiment of the present invention has a solid content of 100 mass of the chloroprene-based polymer latex contained in the chloroprene-based polymer latex composition.
• the content of the vulcanizing agent may be 1 part by mass or less, and the content of the vulcanization accelerator may be 0.5 parts by mass or less.
• chloroprene-based polymer latex composition may be free of vulcanizing agents and vulcanization accelerators, and sulfur and thiuram-based, dithiocarbamate-based, thiourea-based, It can be free of vulcanization accelerators such as guanidine, xanthate, and thiazole.
• a chloroprene-based polymer latex composition according to one embodiment of the present invention is obtained by heating an immersion-molded product containing a chloroprene-based polymer latex composition at 130° C. for 4 hours.
• the rupture strength of the immersion-molded product after heating obtained in the above step measured according to JIS K6251, is preferably 17 MPa or more, more preferably 20 MPa or more.
• the breaking strength is, for example, 39, 40 MPa, and may be in the range between any two of the values exemplified here.
• a chloroprene-based polymer latex composition according to one embodiment of the present invention is a dip-molded article obtained by heating a dip-molded article containing the chloroprene-based polymer latex composition at 130° C. for 4 hours.
• the elongation at break measured according to K6251 is preferably 1000% or more.
• the elongation at break is, for example, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400%, and may be within a range between any two of the values exemplified herein.
• a chloroprene-based polymer latex composition according to one embodiment of the present invention is a dip-molded article obtained by heating a dip-molded article containing the chloroprene-based polymer latex composition at 130° C. for 4 hours.
• the modulus at 100% elongation measured based on K6251 is preferably 0.75 MPa or more, more preferably 0.70 MPa or less.
• the modulus at 100% elongation is, for example, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75 MPa. , within a range between any two of the numerical values exemplified herein.
• the above dip-molded product contains a chloroprene-based polymer latex, a metal oxide, and a heteroaromatic compound, and may further contain an antioxidant. Also, the above dip-molded body can be free of a vulcanizing agent and a vulcanization accelerator.
• the method for producing the dip-molded article and the method for measuring elongation at break, strength at break, and 100% modulus can be as described in Examples.
• the breaking elongation, breaking strength, and modulus at 100% elongation of the dip-molded article containing the chloroprene-based polymer latex composition depend on the type and amount of the chloroprene-based polymer latex composition, and It can be controlled by adjusting the polymerization formulation and conditions of the chloroprene-based polymer latex used, the weight-average molecular weight, the toluene-insoluble matter, and the like.
• a chloroprene-based polymer latex composition according to one embodiment of the present invention is a dip-molded article obtained by heating a dip-molded article containing the chloroprene-based polymer latex composition at 130° C. for 4 hours.
• the modulus at 100% elongation measured based on K6251 can be 0.75 MPa or less and the breaking strength can be 17 MPa or more.
• ASTM standard "D3577" for use in surgical gloves specifies a breaking strength of 17 MPa or more, and 20 MPa can be said to exhibit more sufficient mechanical properties.
• the dip-molded film containing the chloroprene-based polymer latex composition according to one embodiment of the present invention is flexible and has sufficient mechanical strength without containing sulfur or vulcanization accelerators that have concerns about sanitation. can have.
• a method for producing a chloroprene-based polymer latex composition comprises a chloroprene-based polymer latex, a metal oxide, a heteroaromatic compound, and others. It can include a raw material mixing step of mixing raw materials containing required drugs. In the mixing step, an aqueous dispersion containing the metal oxide, the heteroaromatic compound, and other required agents may be prepared in advance, and the chloroprene-based polymer latex and the aqueous dispersion may be mixed. .
• the mixing step can be performed with a known mixing device such as a ball mill.
• a dip-molded article according to one embodiment of the present invention is obtained using the chloroprene-based polymer latex composition described above.
• the dip-molded article of this embodiment is obtained by dip-molding the chloroprene-based polymer latex composition of the first embodiment described above alone or after blending it with another chloroprene-based polymer latex composition. It has a low modulus value when stretched, is flexible, and has excellent mechanical properties such as strength and elongation.
• the dip-molded article can be suitably used as industrial/general household gloves, medical gloves, balloons, catheters and boots.
• the thickness (for example, minimum thickness) of the dip molded body may be 0.01 to 0.50 mm.
• the thickness of the dip molded body is, for example, 0.01, 0.05, 0.10, 0.20, 0.30, 0.40, 0.50 mm. It may be in the range between.
• the thickness of the immersion-molded article can be adjusted by the time for which the mold is immersed in the polymer latex composition, the solid content concentration of the chloroprene-based polymer latex composition, and the like. When it is desired to reduce the thickness of the dip-molded article, the dipping time may be shortened or the solid content concentration of the chloroprene-based polymer latex composition may be lowered.
• the molding method for producing the dip-molded article of one embodiment of the present invention is not particularly limited, and the article may be molded according to a conventional method.
• the forming method includes, for example, a coagulation liquid immersion method, a simple immersion method, a thermal immersion method, an electrodeposition method, and the like.
• the coagulation liquid immersion method can be used from the viewpoint of easy production and the viewpoint of easily obtaining a immersion-molded article having a constant thickness.
• the mold coated with the coagulating liquid is immersed in the chloroprene-based polymer latex composition to coagulate the chloroprene-based polymer latex composition.
• the method for producing a dip-molded article according to one embodiment of the present invention includes the step of heating the obtained dip-molded article to vulcanize the polymer latex composition and the unvulcanized dip-molded article. can.
• the vulcanization temperature may be appropriately set according to the composition of the chloroprene-based polymer latex composition, and may be 100 to 220°C or 110 to 190°C.
• the vulcanization time may be appropriately set according to the composition of the chloroprene-based polymer latex composition, the shape of the unvulcanized molding, and the like, and may be 10 to 300 minutes.
• the dip-molded article according to one embodiment of the present invention has a modulus at 100% elongation measured in accordance with JIS K 6251 of 0.75 MPa or less and a breaking strength of 17 MPa or more. Can be molded.
• the dip molded body according to one embodiment of the present invention has a breaking strength measured according to JIS K6251 of, for example, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29. , 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 MPa, and may be in the range between any two of the values exemplified herein. Further, the dip molded body according to one embodiment of the present invention has a breaking elongation measured based on JIS K6251 of, for example, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400%, where It may be in a range between any two of the numerical values given.
• the dip-molded article according to one embodiment of the present invention has a modulus at 100% elongation measured according to JIS K6251 of, for example, 0.3, 0.35, 0.4, 0.45, 0.5, 0.5. 55, 0.6, 0.65, 0.7, 0.75 MPa, and may be within a range between any two of the numerical values exemplified here.
• the method for producing the dip-molded article and the method for measuring elongation at break, strength at break, and 100% modulus can be as described in Examples.
• the dip-molded body according to one embodiment of the present invention is flexible and can have sufficient mechanical strength without containing sulfur or vulcanization accelerators that may cause hygiene concerns.
• sulfur and a vulcanization accelerator are indispensable in order to obtain a vulcanized rubber having the desired mechanical strength.
• flexibility also deteriorates, making it difficult to achieve both high breaking strength and excellent flexibility.
• the dip-molded article obtained from the chloroprene-based polymer latex composition of the present embodiment may contain sulfur or a vulcanization accelerator.
• the above dip-molded article has mechanical properties equal to or better than vulcanized dip-molded articles obtained from conventional chloroprene-based polymer latexes, even without containing sulfur and vulcanization accelerators. Therefore, the chloroprene-based polymer latex composition of the present embodiment is suitably used as a raw material for dip-molded articles (dip-molded films).
• parts by mass means chloroprene monomer and 2,3-dichloro-1,3-butadiene before starting emulsion polymerization. It is the amount per 100 parts by mass of the monomers. "% by mass” is the amount relative to 100% by mass of the chloroprene-based polymer contained in the chloroprene-based polymer latex.
• the pH of the aqueous emulsion before the initiation of polymerization was 13.2.
• 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and polymerization was carried out at a polymerization temperature of 25° C. under a nitrogen stream.
• the polymerization conversion rate (polymerization rate) reached 82%, 0.01 part by mass of diethylhydroxyamine as a polymerization terminator was added to terminate the polymerization to obtain a latex.
• a chloroprene-based polymer latex with a solid content of 60% was obtained by distilling the latex under reduced pressure to remove unreacted monomers and some water.
• a chloroprene-based polymer latex with a solid content of 60% was obtained by distilling the latex under reduced pressure to remove unreacted monomers.
• Synthesis Examples B2 to B5 The charged amount of 2,3-dichloro-1,3-butadiene and n-dodecylmercaptan as a chain transfer agent, the type and amount of rosin acid, the polymerization temperature, and the polymerization conversion rate were set as shown in Table 1 below. Chloroprene-based polymer latex samples of Synthesis Examples B2 to B5 were prepared in the same manner as in Synthesis Example B1 except for the above.
• the pH of the aqueous emulsion before the initiation of polymerization was 13.1.
• 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and polymerization was carried out at a polymerization temperature of 35° C. under a nitrogen stream.
• 0.01 part by mass of diethylhydroxyamine as a polymerization terminator was added to terminate the polymerization to obtain a latex.
• a chloroprene-based polymer latex with a solid content of 60% was obtained by distilling the latex under reduced pressure to remove unreacted monomers.
• Peak areas of peaks corresponding to dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid and salts thereof, and their total peak areas (total amount a), and abietic acid, neoabietic acid, parastric acid, levopimale The peak areas of the peaks corresponding to acids and salts thereof, and the total peak area (total amount b) of these peaks were determined. Also, the ratio of each of these peak area values to the total peak area value detected by gas chromatography-mass spectrometry was regarded as the content.
• Example 1 When the total of the chloroprene-based polymer latex of Synthesis Example A1 and the chloroprene-based polymer latex of Synthesis Example B1 is 100 parts by mass, the ratio of 75 parts by mass of the sample of Synthesis Example A1 and 25 parts by mass of the sample of Synthesis Example B1 to obtain a mixed chloroprene-based polymer latex.
• ETA solution ethanol/toluene
• the peak area of the peak corresponding to the salt of and the total peak area of these peaks (total amount b) were determined. Also, each of these peak area values relative to the total peak area value detected by gas chromatography-mass spectrometry was regarded as the content.
• the value of (total amount b)/(total amount a) was 0.80.
• Preparation of evaluation sample (immersion molded film)> (Preparation of chloroprene-based polymer latex composition) 100 parts by mass of the solid content of the chloroprene-based polymer latex was mixed with 5.1 parts by mass of the aqueous dispersion, and water was added to adjust the total solid content concentration of the blend to 30% by mass, thereby obtaining the chloroprene-based polymer. A latex composition was made.
• the aqueous dispersion contains 2 parts by weight of two kinds of zinc oxide, 2 parts by weight of a butylated reaction product of p-cresol and dicyclopentadiene (trade name "Nocrac PBK", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), a chemical formula ( 2) 2-Mercaptobenzimidazole (trade name “Nocrac MB”, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), sodium salt of ⁇ -naphthalenesulfonic acid formalin condensate (trade name “Demoll N”, manufactured by Kao Corporation) ) and 13 parts by mass of water were mixed at 20° C. for 16 hours using a ceramic ball mill.
• Nocrac PBK a butylated reaction product of p-cresol and dicyclopentadiene
• a chemical formula ( 2) 2-Mercaptobenzimidazole trade name “Nocrac MB”, manufactured by Ouchi Shinko Kagaku Kogyo Co.,
• the resulting chloroprene-based polymer latex was obtained by adding 2 parts by mass of two types of zinc oxide, a butylated reaction product of p-cresol and dicyclopentadiene (trade name: Nocrack PBK", manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) 2 parts by mass, 2-mercaptobenzimidazole described in the chemical formula (2) (trade name "Noclac MB”, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), ⁇ -naphthalenesulfonic acid It contains 0.1 part by mass of formalin condensate sodium salt (trade name “Demoll N”, manufactured by Kao Corporation) and 13 parts by mass of water.
• the dip-molded product does not contain sulfur and vulcanization accelerators such as thiuram, dithiocarbamate, thiourea, guanidine, xanthate, and thiazole.
• Examples 2 to 15, Comparative Examples 1 to 6 A dip-molded body was prepared in the same manner as in Example 1 except that the formulation of the chloroprene-based polymer latex was changed to the conditions shown in Tables 2, 3, and 4 below. , guanidine-based, xanthate-based, and thiazole-based dip-molded film samples were produced and evaluated.
• the metal oxide zinc oxide, the heteroaromatic compound 2-mercaptobenzimidazole, and the antioxidant contained in the chloroprene-based polymer latex composition The amount of Nocrac PBK added was changed.
• Examples 6, 7, 12 to 15 and Comparative Example 5 the type and mixing ratio of the synthesized polychloroprene-based polymer latex were changed, and the content of the alkylmercaptan compound and the detection value of the weight average molecular weight peak were changed. .
• the heteroaromatic compounds were changed to compounds represented by the following chemical formulas (3) to (6).
• the dip-molded articles (immersion-molded films) obtained using the chloroprene-based polymer latex compositions of the present invention from Examples 1 to 15 had high breaking strength and elongation of 100%.
• the time modulus value was low, that is, it had excellent mechanical properties such as breaking strength and breaking elongation while having very good flexibility.
• Comparative Example 1 was inferior in breaking strength because the heteroaromatic compound was not contained in the chloroprene-based polymer latex composition.
• n-dodecylmercaptan which is an alkyl mercaptan compound
• the modulus 100 value is high and the flexibility is low. Oops.
• hygiene concerns regarding n-dodecyl mercaptan remained, and the odor derived from mercaptan became severe.
• Example 12 using only Synthesis Example A3 and Example 15 in which the value of the weight average molecular weight of the second peak is high, the resulting dip-molded film exhibits sufficiently excellent breaking strength. Furthermore, as in Examples 1 to 11 and 13 to 15, Synthesis Example A containing a high-molecular-weight chloroprene-based polymer and Synthesis Example B containing a low-molecular-weight chloroprene-based polymer were mixed to form a chloroprene-based polymer latex. When the first peak having a weight average molecular weight of 500,000 or more and the second peak having a weight average molecular weight of 7,000 to 80,000 are present, the plasticizing effect of the low molecular weight polymer is exhibited, and the breaking strength is high. It was also confirmed that a dip-molded film having excellent flexibility can be obtained.

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• 2022
  • 2022-09-28 JP JP2023552829A patent/JP7704879B2/ja active Active
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  • 2022-09-28 EP EP22878396.5A patent/EP4389815A4/en not_active Withdrawn
  • 2022-09-28 US US18/693,435 patent/US20240384067A1/en not_active Abandoned
  • 2022-09-28 CN CN202280063266.3A patent/CN117980395A/zh active Pending

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