WO2019058807A1 - Procédé de fabrication de composition de latex - Google Patents

Procédé de fabrication de composition de latex Download PDF

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Publication number
WO2019058807A1
WO2019058807A1 PCT/JP2018/029955 JP2018029955W WO2019058807A1 WO 2019058807 A1 WO2019058807 A1 WO 2019058807A1 JP 2018029955 W JP2018029955 W JP 2018029955W WO 2019058807 A1 WO2019058807 A1 WO 2019058807A1
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Prior art keywords
latex composition
latex
weight
carboxy
producing
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PCT/JP2018/029955
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English (en)
Japanese (ja)
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実紗 林
小出村　順司
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日本ゼオン株式会社
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Priority to JP2019543475A priority Critical patent/JP7163924B2/ja
Publication of WO2019058807A1 publication Critical patent/WO2019058807A1/fr

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    • 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
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
    • 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
    • C08K3/02—Elements
    • C08K3/06—Sulfur
    • 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
    • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
    • C08K5/38—Thiocarbonic acids; Derivatives thereof, e.g. xanthates ; i.e. compounds containing -X-C(=X)- groups, X being oxygen or sulfur, at least one X being sulfur
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C08L101/02—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups
    • C08L101/06—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups containing oxygen atoms
    • C08L101/08—Carboxyl groups
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J113/00—Adhesives based on rubbers containing carboxyl groups
    • C09J113/02—Latex

Definitions

  • the present invention relates to a latex composition, which is capable of suppressing the occurrence of symptoms of delayed allergy (Type IV) in addition to immediate allergy (Type I), and further, a dip-molded product having excellent tensile strength and tear strength, etc.
  • a film-formed article such as a dip-formed article used in contact with the human body such as a teat, a balloon, a glove, a balloon, and a sack by dip-forming a latex composition containing a natural rubber latex.
  • a latex composition containing a natural rubber latex are known.
  • the latex of natural rubber contains a protein that causes symptoms of immediate type allergy (Type I) to the human body, there have been cases where there was a problem as a dip-molded body in direct contact with a mucous membrane or an organ in vivo. Therefore, studies have been made to remove proteins in the latex of natural rubber by purification or the like, or use a latex of synthetic rubber in place of the natural rubber.
  • Patent Document 1 discloses, as a dip-forming composition, a latex composition obtained by blending zinc oxide, sulfur and a vulcanization accelerator with a synthetic polyisoprene latex which is a synthetic rubber.
  • a vulcanization accelerator contained in a dip-molded product when it is a dip-molded product Because of this, when touching the human body, it may cause allergic symptoms of delayed type allergy (Type IV).
  • the present invention has been made in view of such circumstances, and is capable of suppressing the onset of symptoms of delayed allergy (Type IV) in addition to immediate allergy (Type I), and further, tensile strength and tearing.
  • a method for producing a latex composition capable of giving a film molded article such as a dip molded article excellent in strength, a method for producing a dip molded article using the latex composition obtained by such a production method, and adhesion An object of the present invention is to provide a method for producing an agent layer forming base material.
  • the present inventors found that the pH of the carboxy-modified polymer latex is such that a sulfur-based vulcanizing agent, a xanthogen compound, and an activator are mixed. It has been found that the above object can be achieved by ripening a latex composition which is less than 10 under predetermined conditions, and the present invention has been accomplished.
  • the pH of the latex composition after ripening in the ripening step is preferably 6 or more and less than 10.
  • a modification ratio by the carboxyl group in the carboxy modified polymer is (number of carboxyl groups / total number of monomer units of the carboxy modified polymer) ⁇ 100, 0.01 to 100 It is preferable that it is 10 mol%.
  • the content ratio of the xanthogen compound in the latex composition is 0 relative to 100 parts by weight of the carboxy-modified polymer in the latex composition. It is preferable that the amount be 0.1 to 10 parts by weight.
  • the xanthogen compound preferably contains at least zinc diisopropyl xanthate.
  • the latex composition it is preferable that in the preparation step, the latex composition contain two or more of the xanthogen compounds.
  • the metal compound is preferably zinc oxide.
  • the carboxy-modified polymer synthetic polyisoprene, styrene-isoprene-styrene block copolymer, or natural rubber from which a protein is removed, is treated with a monomer having a carboxyl group. It is preferable to use one obtained by denaturing.
  • a method for producing a dip-molded product comprising the step of dip-molding the latex composition obtained by the above-mentioned production method. Furthermore, according to the present invention, there is provided a method for producing an adhesive layer-formed substrate, comprising the step of forming on the substrate surface an adhesive layer formed using the latex composition obtained by the above-mentioned production method. Be done.
  • the present invention provides a method for producing a latex composition capable of giving a body, a method for producing a dip-molded article using the latex composition obtained by such a production method, and a method for producing an adhesive layer-formed substrate. be able to.
  • the method for producing a latex composition of the present invention comprises a latex of a carboxy-modified polymer, a sulfur-based vulcanizing agent, a xanthogen compound, and an activating agent, and a latex composition before aging having a pH of less than 10. And a ripening step of ripening by storing the latex composition before ripening at a temperature of 5 to 60 ° C. for half to 14 days.
  • the latex of the carboxy-modified polymer used in the present invention is a latex of a conjugated diene polymer or a carboxy-modified polymer obtained by modifying a natural rubber from which a protein is removed with a monomer having a carboxyl group.
  • the conjugated diene polymer is not particularly limited, and examples thereof include synthetic polyisoprene, styrene-isoprene-styrene block copolymer (SIS), nitrile group-containing conjugated diene copolymer, and the like. . Among these, those containing isoprene units such as synthetic polyisoprene and SIS are preferable, and synthetic polyisoprene is particularly preferable.
  • the synthetic polyisoprene may be a homopolymer of isoprene or may be a copolymer of isoprene and another ethylenically unsaturated monomer copolymerizable therewith. It may be polymerized.
  • the content of the isoprene unit in the synthetic polyisoprene is preferably 70% by weight or more based on all the monomer units since a flexible film is easily obtained and a film-formed product such as a dip-formed product having excellent tensile strength can be obtained. More preferably, it is 90% by weight or more, still more preferably 95% by weight or more, and particularly preferably 100% by weight (homopolymer of isoprene).
  • Examples of other ethylenically unsaturated monomers copolymerizable with isoprene include conjugated diene monomers other than isoprene such as butadiene, chloroprene and 1,3-pentadiene; acrylonitrile, methacrylonitrile, fumaronitrile, ⁇ - Ethylenically unsaturated nitrile monomers such as chloroacrylonitrile; vinyl aromatic monomers such as styrene, alkylstyrenes; methyl (meth) acrylate ("methyl acrylate and / or methyl methacrylate” meaning: Ethyl (meth) acrylate etc.), ethyl (meth) acrylate, butyl (meth) acrylate, ethylenic unsaturated carboxylic acid ester monomers such as 2-ethylhexyl (meth) acrylate; Can be mentioned.
  • conjugated diene monomers other than isoprene such
  • Synthetic polyisoprene can be prepared in an inert polymerization solvent using a conventionally known method, for example, using a Ziegler type polymerization catalyst consisting of trialkylaluminum-titanium tetrachloride, or an alkyllithium polymerization catalyst such as n-butyllithium or sec-butyllithium. It can be obtained by solution polymerization of isoprene and another copolymerizable ethylenically unsaturated monomer which is optionally used.
  • a Ziegler type polymerization catalyst consisting of trialkylaluminum-titanium tetrachloride, or an alkyllithium polymerization catalyst such as n-butyllithium or sec-butyllithium.
  • the polymer solution of synthetic polyisoprene obtained by solution polymerization may be used as it is for producing synthetic polyisoprene latex, but after taking solid synthetic polyisoprene from the polymer solution, it is dissolved in an organic solvent. It can also be used to make synthetic polyisoprene latex.
  • synthetic polyisoprene latex can be used for manufacture of the latex of the carboxy modified polymer used by this invention so that it may mention later.
  • impurities such as the residue of the polymerization catalyst remaining in the polymer solution may be removed.
  • an anti-aging agent described later may be added to the solution during or after polymerization.
  • commercially available solid synthetic polyisoprene can also be used.
  • the content ratio of cis-bonded units in isoprene units contained in the synthetic polyisoprene is preferably 70% by weight or more based on More preferably, it is 90% by weight or more, still more preferably 95% by weight or more.
  • the weight average molecular weight of the synthetic polyisoprene is preferably 10,000 to 5,000,000, more preferably 500,000 to 5,000,000, further preferably in terms of standard polystyrene by gel permeation chromatography analysis. Is 800,000 to 3,000,000.
  • the polymer Mooney viscosity (ML 1 + 4 at 100 ° C.) of the synthetic polyisoprene is preferably 50 to 80, more preferably 60 to 80, and still more preferably 70 to 80.
  • a synthetic polyisoprene latex for example, (1) emulsifying a solution or a fine suspension of a synthetic polyisoprene dissolved or finely dispersed in an organic solvent in the presence of an anionic surfactant in water And (2) isoprene alone or a mixture of isoprene and an ethylenically unsaturated monomer copolymerizable therewith with an anionic surfactant. And emulsion polymerization or suspension polymerization in the presence of an agent to directly produce a synthetic polyisoprene latex, but synthetic polyisoprene having a high proportion of cis-linking units in isoprene units can be used. , A method of producing the above (1) from the point that a film molded article such as a dip molded article excellent in mechanical properties such as tensile strength is easily obtained It is preferred.
  • Examples of the organic solvent used in the production method of the above (1) include aromatic hydrocarbon solvents such as benzene, toluene and xylene; alicyclic hydrocarbon solvents such as cyclopentane, cyclopentene, cyclohexane and cyclohexene; pentane, hexane, Aliphatic hydrocarbon solvents such as heptane; halogenated hydrocarbon solvents such as methylene chloride, chloroform and ethylene dichloride; and the like.
  • aromatic hydrocarbon solvents such as benzene, toluene and xylene
  • alicyclic hydrocarbon solvents such as cyclopentane, cyclopentene, cyclohexane and cyclohexene
  • pentane, hexane Aliphatic hydrocarbon solvents
  • halogenated hydrocarbon solvents such as methylene chloride, chloroform and ethylene dichloride
  • alicyclic hydrocarbon solvents are
  • the amount of the organic solvent used is preferably 2,000 parts by weight or less, more preferably 20 to 1,500 parts by weight, and still more preferably 500 to 1,500 parts by weight with respect to 100 parts by weight of the synthetic polyisoprene.
  • Fatty acid salts such as sodium laurate, potassium myristate, sodium palmitate, potassium oleate, sodium linolenate, sodium rosinate, etc .
  • dodecyl benzene sulfone Alkyl benzene sulfonates such as sodium acid sodium, potassium dodecyl benzene sulfonate, sodium decyl benzene sulfonate, potassium decyl benzene sulfonate, sodium cetyl benzene sulfonate, potassium cetyl benzene sulfonate
  • sodium di (2-ethylhexyl) sulfosuccinate, disodium Alkyl sulfosuccinates such as potassium (2-ethylhexyl) sulfosuccinate and sodium dioctyl sulfosuccinate
  • fatty acid salts alkyl benzene sulfonates, alkyl sulfosuccinates, alkyl sulfates and polyoxyethylene alkyl ether sulfates are preferable, and fatty acids and alkyl benzene sulfonates are particularly preferable.
  • alkylbenzene it is preferable to use a fatty acid salt in combination with at least one member selected from the group consisting of sulfonates, alkyl sulfosuccinates, alkyl sulfates and polyoxyethylene alkyl ether sulfates, preferably alkyl benzene sulfonates; It is particularly preferable to use a fatty acid salt in combination.
  • fatty acid salt sodium rosinate and potassium rosinate are preferable, and as the alkylbenzene sulfonate, sodium dodecylbenzene sulfonate and potassium dodecylbenzene sulfonate are preferable.
  • these surfactants may be used alone or in combination of two or more.
  • At least one selected from the group consisting of alkyl benzene sulfonate, alkyl sulfosuccinate, alkyl sulfate and polyoxyethylene alkyl ether sulfate and fatty acid salt may be used in combination.
  • Makes the resulting latex contain at least one selected from alkyl benzene sulfonate, alkyl sulfo succinate, alkyl sulfate and polyoxyethylene alkyl ether sulfate, and fatty acid salt .
  • a surfactant other than the anionic surfactant may be used in combination, and as the surfactant other than such an anionic surfactant, ⁇ , ⁇ -unfavorable.
  • Copolymerizable surfactants such as sulfo ester of saturated carboxylic acid, sulfate ester of ⁇ , ⁇ -unsaturated carboxylic acid, sulfoalkyl aryl ether and the like can be mentioned.
  • nonionicity such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester, etc. within the range not inhibiting the coagulation by the coagulant used in dip molding Surfactants may also be used in combination.
  • the amount of the anionic surfactant used in the method of the above (1) is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of the synthetic polyisoprene. is there.
  • the amount of the anionic surfactant used is too small, a large amount of aggregates may be generated at the time of emulsification, while if it is too large, foaming tends to occur, and pinholes are formed in a film molded article such as a dip molded article obtained. Can occur.
  • alkyl benzene sulfonate, alkyl sulfo succinate, alkyl sulfate ester salt and polyoxyethylene alkyl ether sulfate ester salt is used in combination with fatty acid salt as an anionic surfactant
  • the ratio by weight of “total of agents” is preferably in the range of 1: 1 to 10: 1, and more preferably in the range of 1: 1 to 7: 1.
  • the amount of water used in the production method of the above (1) is preferably 10 to 1,000 parts by weight, more preferably 30 to 500 parts by weight, most preferably 100 parts by weight of the synthetic polyisoprene solution in organic solvent. Is 50 to 100 parts by weight.
  • the types of water used include hard water, soft water, ion-exchanged water, distilled water, zeolite water and the like, and soft water, ion-exchanged water and distilled water are preferable.
  • An apparatus for emulsifying a solution or a fine suspension of synthetic polyisoprene dissolved or finely dispersed in an organic solvent in water in the presence of an anionic surfactant is generally commercially available as an emulsifying machine or dispersing machine.
  • the method for adding the anionic surfactant to the solution or fine suspension of the synthetic polyisoprene is not particularly limited, and it may be preliminarily carried out to either water or a solution or fine suspension of the synthetic polyisoprene, or both. It may be added, or may be added to the emulsion during the emulsification operation, may be added all at once, or may be added in portions.
  • batch-type emulsification such as trade name "homogenizer” (manufactured by IKA), trade name “Polytron” (manufactured by Kinematica), trade name “TK autohomomixer” (manufactured by Tokushu Kika Kogyo) Machine name: "TK pipeline homomixer” (manufactured by Tokushu Kika Kogyo Co., Ltd.), trade name “colloid mill” (manufactured by Shinko Pantec Co., Ltd.), trade name “Slasher” (manufactured by Japan Coke Industry Co., Ltd.), trade name " Trigonal wet pulverizer (made by Mitsui Miike Kako Co., Ltd.), trade name “Cavitron” (made by Eurotech Co., Ltd.), trade name “Milder” (manufactured by Pacific Kikko Co., Ltd.), trade name “Fine Flow Mill” (Pacific Kikko Co.,
  • an organic solvent from the emulsion obtained through emulsification operation.
  • a method of removing the organic solvent from the emulsion a method capable of adjusting the content of the organic solvent (preferably an alicyclic hydrocarbon solvent) in the resultant synthetic polyisoprene latex to 500 ppm by weight or less is preferable.
  • methods such as vacuum distillation, atmospheric distillation, steam distillation, and centrifugation can be employed.
  • the synthetic polyisoprene latex by removing the organic solvent from the emulsion obtained through the emulsification operation.
  • the total content of the alicyclic hydrocarbon solvent and the aromatic hydrocarbon solvent as the organic solvent in the resultant synthetic polyisoprene latex can be 500 ppm by weight or less
  • the method is not particularly limited as long as it is such a method, and methods such as vacuum distillation, atmospheric pressure distillation, steam distillation, centrifugation and the like can be adopted.
  • concentration operation may be performed by a method such as vacuum distillation, atmospheric pressure distillation, centrifugation, membrane concentration, etc.
  • centrifugal separation it is preferable to carry out centrifugal separation from the viewpoint that the solid content concentration of the synthetic polyisoprene latex can be increased and the residual amount of surfactant in the synthetic polyisoprene latex can be reduced.
  • Centrifugation is carried out, for example, using a continuous centrifugal separator, preferably 100 to 10,000 G, solid concentration of synthetic polyisoprene latex before centrifugation, preferably 2 to 15% by weight, centrifugation
  • the flow rate to be fed into the machine is preferably 500 to 1700 kg / hr, and the back pressure (gauge pressure) of the centrifuge is preferably 0.03 to 1.6 MPa.
  • synthetic polyisoprene latex can be obtained. And thereby, the residual amount of surfactant in synthetic polyisoprene latex can be reduced.
  • the solids concentration of the synthetic polyisoprene latex is preferably 30 to 70% by weight, more preferably 40 to 70% by weight. If the solid content concentration is too low, the solid content concentration of the latex composition to be described later becomes low, so the film thickness of the dip molded product to be described later becomes thin and it is easy to break. Conversely, if the solid concentration is too high, the viscosity of the synthetic polyisoprene latex may be high, which may make it difficult to transfer by piping or to stir in the mixing tank.
  • the volume average particle size of the synthetic polyisoprene latex is preferably 0.1 to 10 ⁇ m, more preferably 0.5 to 3 ⁇ m, and still more preferably 0.5 to 2.0 ⁇ m.
  • synthetic polyisoprene latex contains additives such as pH adjusters, antifoaming agents, preservatives, crosslinking agents, chelating agents, oxygen scavengers, dispersants, anti-aging agents, etc., which are usually blended in the field of latexes. You may mix
  • pH adjusters include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; carbonates of alkali metals such as sodium carbonate and potassium carbonate; hydrogencarbonates of alkali metals such as sodium hydrogencarbonate; ammonia Organic amine compounds such as trimethylamine and triethanolamine; and the like, and hydroxides of alkali metals or ammonia are preferable.
  • the pH of the synthetic polyisoprene latex at this time is not particularly limited, but in the production method of the present invention, as described later, a synthetic polyisoprene latex or the like is used to form a latex composition, and the latex composition is When ripening under the conditions, the pH of the latex composition before ripening should be less than 10.
  • SIS styrene-isoprene-styrene block copolymer
  • SIS can be obtained by block copolymerization of isoprene and styrene in an inert polymerization solvent using an active organic metal such as n-butyllithium as an initiator and a method known in the art. And although the obtained polymer solution of SIS may be used as it is for production of SIS latex, after taking out solid SIS from the polymer solution, the solid SIS is dissolved in an organic solvent to obtain SIS. It can also be used for the production of latex. In addition, SIS latex can be used for manufacture of the latex of the carboxy modified polymer used by this invention so that it may mention later.
  • the method for producing SIS latex is not particularly limited, but a solution or fine suspension of SIS dissolved or finely dispersed in an organic solvent is emulsified in water in the presence of a surfactant, and the organic solvent is optionally removed Preferred is a method of producing SIS latex.
  • impurities such as the residue of the polymerization catalyst remaining in the polymer solution after synthesis may be removed.
  • an anti-aging agent described later may be added to the solution during or after polymerization.
  • commercially available solid SIS can be used.
  • organic solvent the same ones as in the case of the above-mentioned synthetic polyisoprene can be used, and aromatic hydrocarbon solvents and alicyclic hydrocarbon solvents are preferable, and cyclohexane and toluene are particularly preferable.
  • the amount of the organic solvent used is usually 50 to 2,000 parts by weight, preferably 80 to 1,000 parts by weight, more preferably 10 to 500 parts by weight, and still more preferably 150 to 300 parts by weight per 100 parts by weight of SIS. It is a weight part.
  • surfactant those similar to the above-mentioned synthetic polyisoprene can be exemplified, and an anionic surfactant is preferable, and sodium rosinate and sodium dodecylbenzene sulfonate are particularly preferable.
  • the amount of surfactant used is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of SIS. If this amount is too small, the stability of the latex tends to be poor, and on the other hand, if it is too large, foaming tends to occur and problems may occur during dip molding.
  • the amount of water used in the method of producing SIS latex described above is preferably 10 to 1,000 parts by weight, more preferably 30 to 500 parts by weight, most preferably 50 parts by weight with respect to 100 parts by weight of the SIS organic solvent solution. It is up to 100 parts by weight.
  • the types of water used include hard water, soft water, ion-exchanged water, distilled water, zeolite water and the like.
  • polar solvents represented by alcohols such as methanol may be used in combination with water.
  • An apparatus for emulsifying an organic solvent solution or a fine suspension of SIS in water in the presence of a surfactant may be the same as in the case of the above-mentioned synthetic polyisoprene.
  • the addition method of the surfactant is not particularly limited, and may be added in advance to either or both of water and an organic solvent solution of SIS or a fine suspension, or both, during the emulsification operation. May be added to the emulsion, may be added all at once, or may be added separately.
  • the method for producing SIS latex described above it is preferable to obtain the SIS latex by removing the organic solvent from the emulsion obtained through the emulsification operation.
  • the method for removing the organic solvent from the emulsion is not particularly limited, and methods such as vacuum distillation, atmospheric distillation, steam distillation, centrifugation and the like can be employed.
  • a concentration operation may be performed by a method such as vacuum distillation, atmospheric pressure distillation, centrifugation, or membrane concentration.
  • the solids concentration of the SIS latex is preferably 30 to 70% by weight, more preferably 50 to 70% by weight. If the solid content concentration is too low, the solid content concentration of the latex composition to be described later will be low, and the film thickness of the dip-formed product will be thin and it will be easy to break. On the other hand, if the solid concentration is too high, the viscosity of the SIS latex becomes high, which makes it difficult to transfer by piping or to stir in the mixing tank.
  • SIS latex contains additives such as pH adjusters, antifoaming agents, preservatives, crosslinking agents, chelating agents, oxygen scavengers, dispersants, anti-aging agents, etc., which are usually blended in the field of latex. It is good.
  • As the pH adjuster those similar to the above-mentioned synthetic polyisoprene can be exemplified, and alkali metal hydroxide or ammonia is preferable.
  • the pH of the SIS latex at this time is not particularly limited, but in the production method of the present invention, as described later, a SIS latex or the like is used to form a latex composition, and the latex composition is aged under predetermined conditions. At this time, the pH of the latex composition before aging may be less than 10.
  • the content of styrene units in styrene blocks in SIS contained in the SIS latex thus obtained is preferably 70 to 100% by weight, more preferably 90 to 100% by weight, based on all monomer units. More preferably, it is 100% by weight.
  • the content of isoprene units in the isoprene block in SIS is preferably 70 to 100% by weight, more preferably 90 to 100% by weight, and still more preferably 100% by weight, based on all monomer units.
  • the content ratio of styrene unit and isoprene unit in SIS is usually 1:99 to 90:10, preferably 3:97 to 70:30, more preferably 5 in weight ratio of "styrene unit: isoprene unit". The preferred range is 95 to 50:50, more preferably 10:90 to 30:70.
  • the weight-average molecular weight of SIS is preferably 10,000 to 1,000,000, more preferably 50,000 to 50,000, still more preferably 100, in terms of standard polystyrene determined by gel permeation chromatography analysis. It is between 4,000 and 3,00,000.
  • the volume average particle size of the latex particles (SIS particles) in the SIS latex is preferably 0.1 to 10 ⁇ m, more preferably 0.5 to 3 ⁇ m, and still more preferably 0.5 to 2.0 ⁇ m.
  • conjugated diene polymer as described above, a nitrile group-containing conjugated diene copolymer can also be used.
  • the nitrile group-containing conjugated diene-based copolymer is a copolymer obtained by copolymerizing an ethylenically unsaturated nitrile monomer with a conjugated diene monomer, and in addition to these, it is used as needed. And a copolymer formed by copolymerizing another ethylenically unsaturated monomer copolymerizable therewith.
  • conjugated diene monomers examples include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and chloroprene. Be Among these, 1,3-butadiene and isoprene are preferable, and 1,3-butadiene is more preferable. These conjugated diene monomers can be used alone or in combination of two or more.
  • the content of the conjugated diene monomer unit formed by the conjugated diene monomer in the nitrile group-containing conjugated diene copolymer is preferably 56 to 78% by weight, more preferably 56 to 73% by weight More preferably, it is 56 to 68% by weight.
  • the ethylenically unsaturated nitrile monomer is not particularly limited as long as it is a nitrile group-containing ethylenically unsaturated monomer, but, for example, acrylonitrile, methacrylonitrile, fumaronitrile, ⁇ -chloroacrylonitrile, ⁇ -cyanoethyl acrylonitrile Etc. Among these, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable. These ethylenically unsaturated nitrile monomers can be used alone or in combination of two or more.
  • the content ratio of the ethylenically unsaturated nitrile monomer unit formed by the ethylenically unsaturated nitrile monomer in the nitrile group-containing conjugated diene copolymer is preferably 20 to 40% by weight, and more preferably Is 25 to 40% by weight, more preferably 30 to 40% by weight.
  • Examples of the conjugated diene monomer and other ethylenically unsaturated monomers copolymerizable with the ethylenically unsaturated nitrile monomer include, for example, an ethylenically unsaturated monomer which is an ethylenically unsaturated monomer containing a carboxyl group.
  • Saturated carboxylic acid monomers vinyl aromatic monomers such as styrene, alkylstyrenes and vinylnaphthalenes; fluoroalkyl vinyl ethers such as fluoroethyl vinyl ether; (meth) acrylamides, N-methylol (meth) acrylamides, N, N-dimethylol Ethylenically unsaturated amide monomers such as (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Butyl acrylate, (meth) acrylic acid-2-ethyl Hexyl, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, dibutyl maleate, dibutyl fumarate, diethyl maleate, methoxy
  • the ethylenically unsaturated carboxylic acid monomer is not particularly limited as long as it is a carboxyl group-containing ethylenically unsaturated monomer, but, for example, a single amount of an ethylenically unsaturated monocarboxylic acid such as acrylic acid or methacrylic acid Body: Ethylenically unsaturated polyvalent carboxylic acid monomers such as itaconic acid, maleic acid, fumaric acid; Ethylenically unsaturated polyvalent carboxylic acid anhydrides such as maleic anhydride, citraconic acid; Monobutyl fumarate, Maleic acid And ethylenically unsaturated polyhydric carboxylic acid partial ester monomers such as monobutyl and mono-2-hydroxypropyl maleate; and the like.
  • Ethylenically unsaturated polyvalent carboxylic acid monomers such as itaconic acid, maleic acid, fumaric acid
  • ethylenically unsaturated monocarboxylic acids are preferable, and methacrylic acid is particularly preferable.
  • These ethylenically unsaturated carboxylic acid monomers can also be used as alkali metal salts or ammonium salts.
  • an ethylenically unsaturated carboxylic acid monomer can be used individually or in combination of 2 or more types.
  • the content ratio of the ethylenically unsaturated carboxylic acid monomer unit formed of the ethylenically unsaturated carboxylic acid monomer in the nitrile group-containing conjugated diene copolymer is preferably 2 to 5% by weight.
  • the obtained film molded product such as a dip molded product is excellent in feeling and elongation while making the tensile strength sufficient. can do.
  • the content ratio of other monomer units formed of other ethylenically unsaturated monomers in the nitrile group-containing conjugated diene copolymer is preferably 10% by weight or less, more preferably 5% by weight. % Or less, more preferably 3% by weight or less.
  • the nitrile group-containing conjugated diene-based copolymer can be obtained by copolymerizing a monomer mixture containing the above-mentioned monomers, but a method of copolymerizing by emulsion polymerization is preferable. A conventionally known method can be adopted as the emulsion polymerization method.
  • polymerization auxiliary materials such as an emulsifier, a polymerization initiator, a molecular weight modifier and the like can be used.
  • the addition method of these polymerization auxiliary materials is not particularly limited, and any method such as initial batch addition method, split addition method, continuous addition method may be used.
  • the emulsifier is not particularly limited.
  • nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester, etc .
  • potassium dodecyl benzene sulfonate dodecyl benzene
  • Anionic emulsifiers such as alkyl benzene sulfonates such as sodium sulfonate, higher alcohol sulfates, alkyl sulfosuccinates
  • cationic emulsifiers such as alkyl trimethyl ammonium chlorides, dialkyl ammonium chlorides and benzyl ammonium chlorides; ⁇ , ⁇ -unsaturated Sulfo esters of carboxylic acids, sulfate esters of ⁇ , ⁇ -unsaturated carboxylic acids, sulfoalkyl aryl ethers
  • a polymerizable emulsifier can be mentioned.
  • anionic emulsifiers are preferable, alkylbenzene sulfonates are more preferable, and potassium dodecylbenzenesulfonate and sodium dodecylbenzenesulfonate are particularly preferable.
  • These emulsifiers can be used alone or in combination of two or more.
  • the amount of the emulsifier used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer mixture.
  • the polymerization initiator is not particularly limited, and for example, inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, hydrogen peroxide and the like; diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-Butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, di- ⁇ - Organic peroxides such as cumyl peroxide, acetyl peroxide, isobutyryl peroxide, benzoyl peroxide; azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, methyl azobisisobutyrate, etc.
  • inorganic peroxides such as sodium persulfate, potassium persul
  • the amount of the polymerization initiator used is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 2 parts by weight, with respect to 100 parts by weight of the monomer mixture.
  • the peroxide initiator can be used as a redox polymerization initiator in combination with a reducing agent.
  • the reducing agent is not particularly limited, but is a compound containing a metal ion in a reduced state such as ferrous sulfate or cuprous naphthenate; a sulfonic acid compound such as sodium methanesulfonate; an amine compound such as dimethylaniline And the like. These reducing agents can be used alone or in combination of two or more.
  • the amount of the reducing agent used is preferably 3 to 1000 parts by weight with respect to 100 parts by weight of the peroxide.
  • the amount of water used in the emulsion polymerization is preferably 80 to 600 parts by weight, particularly preferably 100 to 200 parts by weight, with respect to 100 parts by weight of all the monomers used.
  • a method of adding monomers for example, a method of adding monomers to be used in a reaction vessel at once, a method of adding continuously or intermittently as polymerization progresses, a part of monomers is added The reaction may be carried out to a specific conversion rate, and then the remaining monomers may be continuously or intermittently added and polymerized, and any method may be employed.
  • the composition of the mixture may be constant or may be changed.
  • each monomer may be added to the reaction container after previously mixing various monomers to be used, or may be separately added to the reaction container.
  • a polymerization auxiliary material such as a chelating agent, a dispersing agent, a pH regulator, an oxygen scavenger, a particle size regulator and the like can be used, and the type and amount thereof are not particularly limited.
  • the polymerization temperature at the time of carrying out the emulsion polymerization is not particularly limited, but is usually 3 to 95 ° C., preferably 5 to 60 ° C.
  • the polymerization time is about 5 to 40 hours.
  • the monomer mixture is emulsion-polymerized, and when reaching a predetermined polymerization conversion rate, the polymerization reaction is stopped by cooling the polymerization system or adding a polymerization terminator.
  • the polymerization conversion rate at the time of terminating the polymerization reaction is preferably 90% by weight or more, more preferably 93% by weight or more.
  • the polymerization terminator is not particularly limited, and examples thereof include hydroxylamine, hydroxyamine sulfate, diethylhydroxylamine, hydroxyamine sulfonic acid and alkali metal salt thereof, sodium dimethyldithiocarbamate, hydroquinone derivative, catechol derivative, and hydroxydimethyl Aromatic hydroxy dithio carboxylic acids, such as benzene thio carboxylic acid, hydroxy diethyl benzene dithio carboxylic acid, hydroxy dibutyl benzene dithio carboxylic acid, and these alkali metal salts etc. are mentioned.
  • the amount of polymerization terminator used is preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the monomer mixture.
  • an anti-aging agent an antiseptic agent, an antibacterial agent, a dispersing agent, and the like may be appropriately added to the latex of the nitrile group-containing conjugated diene copolymer as needed.
  • the number average particle diameter of the latex of the nitrile group-containing conjugated diene copolymer is preferably 60 to 300 nm, more preferably 80 to 150 nm.
  • the particle size can be adjusted to a desired value by a method such as adjusting the amount of the emulsifier and the polymerization initiator used.
  • carboxy-modified polymer used in the present invention as described above, synthetic polyisoprene, styrene-isoprene-styrene block copolymer (SIS), nitrile group-containing conjugated diene copolymer and the like can be used. Not limited to these, a butadiene polymer, a styrene-butadiene copolymer, etc. may be used.
  • SIS styrene-isoprene-styrene block copolymer
  • nitrile group-containing conjugated diene copolymer and the like can be used.
  • a butadiene polymer, a styrene-butadiene copolymer, etc. may be used.
  • the butadiene polymer may be a homopolymer of 1,3-butadiene as a conjugated diene monomer, or another ethylenic non-copolymerizable with 1,3-butadiene as a conjugated diene monomer. It may be a copolymer obtained by copolymerizing a saturated monomer.
  • a styrene-butadiene copolymer is a copolymer obtained by copolymerizing styrene with 1,3-butadiene as a conjugated diene monomer, and in addition to these, it is used as needed. It may be a copolymer formed by copolymerizing another copolymerizable ethylenically unsaturated monomer.
  • a latex of a natural rubber from which proteins have been removed can also be used.
  • the latex of deproteinized natural rubber can be obtained by a known protein removing method such as a method of decomposing the protein in the natural rubber latex with, for example, a proteolytic enzyme or surfactant and removing it by washing, centrifugation or the like What is known as so-called "deproteinized natural rubber latex" can be used.
  • Carboxy-modified polymer constituting the latex of the carboxy-modified polymer used in the latex present invention carboxy-modified polymer, a conjugated diene polymer or deproteinized natural rubber as described above, be modified by a monomer having a carboxyl group It can be obtained by Alternatively, when a polymer containing an ethylenically unsaturated carboxylic acid monomer unit is used as a conjugated diene polymer, the conjugated diene polymer is modified with a monomer having a carboxyl group. Instead, the conjugated diene polymer can be used as it is as a carboxy-modified polymer.
  • the present invention by using a latex of a carboxy-modified polymer, generation of aggregates can be suppressed for the obtained latex composition, whereby a dip-molded product or the like can be obtained using the latex composition.
  • the defect rate of the film-formed body can be reduced.
  • the obtained latex composition can improve the tensile strength when it is formed into a film molded article such as a dip molded article.
  • the method for modifying a conjugated diene polymer or a deproteinized natural rubber with a monomer having a carboxyl group is not particularly limited.
  • a conjugated diene polymer or a deproteinized natural rubber having a carboxyl group may be used alone.
  • the method of graft-polymerizing a monomer in an aqueous phase is mentioned.
  • the method of graft polymerizing a monomer having a carboxyl group in the aqueous phase is not particularly limited, and a conventionally known method may be used, for example, a conjugated diene polymer or a latex of deproteinized natural rubber, After adding a monomer having a carboxyl group and a polymerization catalyst (graft polymerization catalyst) used for graft polymerization, a monomer having a carboxyl group in a conjugated diene polymer or deproteinized natural rubber in an aqueous phase The method of reacting is preferred.
  • graft polymerization catalyst graft polymerization catalyst
  • the graft polymerization catalyst is not particularly limited.
  • inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, hydrogen peroxide and the like; diisopropylbenzene hydroperoxide, cumene hydroperoxide, Organic peroxides such as t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, isobutyryl peroxide, benzoyl peroxide; 2,2'- Although azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, methyl azobisisobutyrate and the like can be mentioned, the tensile strength of a film molded product such as a dip molded product obtained is further improved Organic peroxides are preferred in terms of , 1,1,3,3-tetramethylbutyl hydroperoxide is particularly
  • the amount of the graft polymerization catalyst used varies depending on its type, but it is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the conjugated diene polymer or deproteinized natural rubber. It is a department. Moreover, it does not specifically limit as method to add a graft polymerization catalyst, Well-known addition methods, such as package addition, division
  • an organic peroxide When used as a graft polymerization catalyst, it can be used as a redox polymerization initiator in combination with a reducing agent.
  • the reducing agent is not particularly limited.
  • compounds containing metal ions in a reduced state such as ferrous sulfate and cuprous naphthenate; Sulfonic acid compounds such as sodium methanesulfonate; Amines such as dimethylaniline Compound; and the like.
  • One of these reducing agents may be used alone, or two or more thereof may be used in combination.
  • the addition amount of the organic peroxide is not particularly limited, it is preferably 0.01 to 3 parts by weight, more preferably 0.1 to 1 part by weight with respect to 100 parts by weight of the conjugated diene polymer or the deproteinized natural rubber. It is a department.
  • the addition amount of the reducing agent is not particularly limited, it is preferably 0.01 to 1 part by weight with respect to 1 part by weight of the organic peroxide.
  • the addition method of the organic peroxide and the reducing agent is not particularly limited, and known addition methods such as batch addition, divided addition, continuous addition and the like can be used, respectively.
  • the dispersant is not particularly limited. However, derivatives of aromatic sulfonic acids, fatty acid salts, alkylbenzene sulfonates, alkyl sulfosuccinates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, monoalkyl phosphates, etc. Anionic surfactants are preferred, and derivatives of aromatic sulfonic acids are more preferred.
  • the dispersants may be used alone or in combination of two or more.
  • the derivative of the aromatic sulfonic acid is not particularly limited, but a compound represented by the following general formula (1) is preferable.
  • R 1 and R 2 are each independently a hydrogen atom or any organic group, and R 1 and R 2 may be bonded to each other to form a ring structure .
  • the organic group can be an R 1 and R 2, but not limited to, methyl group, ethyl group, n- propyl group, an isopropyl group, n- butyl group, an isobutyl group Alkyl groups having 1 to 30 carbon atoms, such as sec-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; A cycloalkyl group having 3 to 30 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; and an aryl having 6 to 30 carbons such as phenyl, biphenyl, naphthyl and anthranyl.
  • These organic groups may have a substituent, and the position of the substituent can be any position.
  • the ring structure is not particularly limited, but an aromatic compound is preferable, and an aromatic compound having a benzene ring such as benzene and naphthalene is preferable. More preferred is naphthalene.
  • aromatic compound having a benzene ring such as benzene and naphthalene is preferable. More preferred is naphthalene.
  • These ring structures may have a substituent, and the position of the substituent may be any position.
  • R 1 and R 2 are mutually bonded to form a ring structure, What forms the benzene ring structure in the said General formula (1) is mentioned. More specifically, it is preferable to use a compound having a structure represented by the following general formula (2).
  • R 3 is a divalent hydrocarbon group which may have a substituent.
  • R 3 is not particularly limited as long as it is a divalent hydrocarbon group which may have a substituent, and is preferably an alkylene group having 1 to 10 carbon atoms, and a methylene group Is particularly preferred.
  • the structure represented by the said General formula (2) it is preferable to have the structure represented by the said General formula (2) repeatedly, and the repeating unit number of the structure represented by the said General formula (2) is not specifically limited Is preferably 10 to 100, more preferably 20 to 50.
  • the weight average molecular weight of the derivative of aromatic sulfonic acid is preferably 500 to 100,000, more preferably 3,000 to 50,000, and still more preferably 5,000 to 30,000.
  • the addition amount of the dispersant is not particularly limited, it is possible to more effectively suppress the generation of aggregates even when the solid concentration of the conjugated diene polymer or the latex of the deproteinized natural rubber is increased. More preferably, the amount is 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the conjugated diene polymer or deproteinized natural rubber contained in the latex.
  • the method for adding the dispersant to the conjugated diene polymer or the latex of deproteinized natural rubber is not particularly limited, and known addition methods such as batch addition, divided addition, continuous addition, and the like can be adopted.
  • the dispersant may be added directly to the latex, or an aqueous solution of the dispersant may be prepared beforehand, and the prepared aqueous solution of the dispersant may be added to the latex.
  • the reaction temperature for reacting the conjugated diene polymer or the deproteinized natural rubber with a monomer having a carboxyl group is not particularly limited, but is preferably 15 to 80 ° C., more preferably 30 to 50 ° C.
  • the reaction time for reacting a monomer having a carboxyl group may be appropriately set according to the above reaction temperature, but is preferably 30 to 300 minutes, more preferably 60 to 120 minutes.
  • the solid concentration of the conjugated diene polymer or latex of the deproteinized natural rubber when reacting a monomer having a carboxyl group is not particularly limited, but is preferably 5 to 60% by weight, more preferably 10 to 40. It is weight%.
  • Examples of the monomer having a carboxyl group include ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; and ethylenically unsaturated polyvalent acids such as itaconic acid, maleic acid, fumaric acid and butene tricarboxylic acid Carboxylic acid monomer; Partial ester monomer of ethylenically unsaturated polyvalent carboxylic acid such as monobutyl fumarate, monobutyl maleate, mono 2-hydroxypropyl maleate; Polyvalent carbon such as maleic anhydride, citraconic anhydride Acid anhydrides and the like can be mentioned, but from the viewpoint that the effect of the present invention becomes more remarkable, ethylenically unsaturated monocarboxylic acid monomers are preferable, and acrylic acid and methacrylic acid are particularly preferable. These monomers may be used alone or in combination of two or more. Further, the above-mentioned carboxyl group also includes those in the form of
  • the amount of the carboxyl group-containing monomer used is preferably 0.01 parts by weight to 100 parts by weight, more preferably 0.01 parts by weight to 100 parts by weight of the conjugated diene polymer or deproteinized natural rubber.
  • the amount is 40 parts by weight, more preferably 0.5 to 20 parts by weight.
  • the conversion of graft polymerization is preferably 95% by weight or more, more preferably 97% by weight or more.
  • the modification ratio of the carboxy-modified polymer by the monomer having a carboxyl group may be appropriately controlled depending on the purpose of use of the resulting latex composition, but is preferably 0.01 to 10 mol%, more preferably 0. 5 to 5 mol%.
  • the modification rate is represented by the following formula (i).
  • Modification rate (mol%) (X / Y) ⁇ 100 (i)
  • X represents the number of carboxyl groups in the carboxy-modified polymer
  • Y represents the total number of monomer units of the carboxy-modified polymer.
  • X can be determined by performing 1 H-NMR measurement on the carboxy-modified polymer. Further, Y can be determined by calculating (weight-average molecular weight (Mw) of carboxy-modified polymer) / (average molecular weight according to the content ratio of each monomer unit constituting the carboxy-modified polymer).
  • the latex of the carboxy modified polymer used in the present invention is added with a pH adjusting agent, an antifoaming agent, an antiseptic agent, a chelating agent, an oxygen scavenger, a dispersing agent, an antiaging agent, etc.
  • An agent may be blended.
  • pH adjusters include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; carbonates of alkali metals such as sodium carbonate and potassium carbonate; hydrogencarbonates of alkali metals such as sodium hydrogencarbonate; ammonia Organic amine compounds such as trimethylamine and triethanolamine; and the like, and hydroxides of alkali metals or ammonia are preferable.
  • the pH of the latex of the carboxy modified polymer at this time is not particularly limited, but in the production method of the present invention, as described later, the latex of the carboxy modified polymer contains a xanthogen compound, an activator, and a sulfur system. When a vulcanizing agent is blended to form a latex composition and the latex composition is aged under predetermined conditions, the pH of the latex composition before aging may be less than 10.
  • concentration operation may be performed by a method such as vacuum distillation, atmospheric pressure distillation, centrifugation, membrane concentration, etc. It is preferable to perform centrifugation from the viewpoint that the residual amount of the anionic surfactant in the latex of the carboxy-modified polymer can be adjusted.
  • the latex of the carboxy-modified polymer after graft polymerization is centrifuged, it is preferable to add a pH adjuster in advance to set the pH of the latex to 7 or more, in order to improve the mechanical stability of the latex. Is more preferably 9 or more.
  • denaturation may be in the state of a salt.
  • the pH of the latex of the carboxy modified polymer even when the pH of the latex of the carboxy modified polymer is adjusted at this time, as described later, the xanthogen compound, the activator, and the latex of the carboxy modified polymer And when a sulfur-based vulcanizing agent is blended to form a latex composition, and the latex composition is aged under predetermined conditions, the pH of the latex composition before aging may be less than 10.
  • the solids concentration of the latex of the carboxy-modified polymer of the present invention is preferably 30 to 70% by weight, more preferably 40 to 70% by weight.
  • the content ratio of the monomer unit having a carboxyl group in the carboxy-modified polymer is the total unit amount The amount is preferably 0.01 to 50% by weight, more preferably 0.5 to 40% by weight, still more preferably 1 to 30% by weight, and particularly preferably 1 to 15% by weight, based on the body unit.
  • a xanthogen compound is blended in the latex of the carboxy modified polymer described above.
  • the xanthogen compound used in the present invention can act as a vulcanization accelerator by using it in combination with a sulfur-based vulcanizing agent described later. That is, when a sulfur-based vulcanizing agent is blended in the latex composition, and the carboxy-modified polymer in the latex composition is vulcanized with the sulfur-based vulcanizing agent to form a film molded article such as a dip molded article, The xanthogen compound acts as a vulcanization accelerator.
  • xanthogen compounds act as a vulcanization accelerator in a latex composition containing a sulfur-based vulcanizing agent, and after vulcanization is performed, alcohol and carbon disulfide are added by the heat applied at the time of vulcanization, etc. And so on.
  • a xanthogen compound is decomposed into alcohol, carbon disulfide and the like by heat (heat at about 100 to 130 ° C. when vulcanizing a carboxy-modified polymer) added when producing a film molded product, and further decomposed The components (alcohol and carbon disulfide etc.) generated by As a result, the resulting molded membrane has a reduced amount of residual xanthogen compound.
  • a vulcanization accelerator for example, a dithiocarbamate-based vulcanization accelerator, a thiazole-based vulcanization accelerator, etc. which has conventionally caused the occurrence of symptoms of delayed type allergy (Type IV) Since the xanthogen compound can be used as a vulcanization accelerator without reducing the residual amount of the xanthogen compound in a film molded article such as a dip molded product to be obtained, delay of the film molded article obtained can be obtained. It is possible to suppress the occurrence of symptoms of type allergy (Type IV).
  • the latex composition used in the present invention uses a synthetic rubber such as a conjugated diene polymer or a carboxy-modified polymer using a deproteinized natural rubber, natural rubber ( It is also possible to suppress the occurrence of the symptoms of immediate type allergy (Type I) caused by the protein contained in the natural rubber (not deproteinized).
  • xanthogen compounds used in the present invention include, but are not limited to, xanthogen acid, xanthogen acid salt, xanthogen disulfide (compound in which two xanthogen acids are linked via a sulfur atom etc.), xanthogen polysulfide And the like) compounds in which three or more xanthogenic acids are linked via a sulfur atom or the like.
  • the xanthogen acid salt is not particularly limited as long as it has a xanthogenic acid structure, and is not particularly limited.
  • a general formula (ROC ( S) S) x-Z (wherein R is linear or branched) Hydrocarbon, Z is a metal atom, and x is a number corresponding to the valence of Z, and is usually 1 to 4, preferably 2 to 4, particularly preferably 2.
  • xanthogenates may be used alone or in combination of two or more.
  • the xanthogen disulfide is a compound in which two xanthogenic acids are linked via a sulfur atom or the like, and is not particularly limited, but dimethyl xanthogen disulfide, diethyl xanthogen disulfide, diisopropyl xanthogen disulfide, dibutyl xanthogen disulfide, dimethyl xanthogen polysulfide, diethyl Examples thereof include xanthogen polysulfide, diisopropyl xanthogen polysulfide, dibutyl xanthogen polysulfide and the like, and among these, diisopropyl xanthogen disulfide and dibutyl xanthogen disulfide are preferable.
  • a xanthogen polysulfide is a compound in which three or more xanthogenic acids are linked via a sulfur atom or the like, and xanthogen trisulfide in which three xanthogenic acids are linked via sulfur, and four xanthogenic acids via sulfur And xanthogen pentasulfide, in which five xanthogen acids are linked via sulfur.
  • xanthogen compounds may be contained singly in the latex composition, but two or more kinds are preferably contained.
  • xanthogenic acid when xanthogenic acid is compounded into the latex composition, part of the compounded xanthogenic acid is present in the form of xanthogenate, and as a result, the latex composition contains two or more xanthogen compounds.
  • a part of xanthogenic acid blended into the latex composition may be present in the form of xanthogen disulfide or xanthogen polysulfide by the action of the sulfur-based vulcanizing agent in the latex composition.
  • any of xanthogen acid, xanthogenate, xanthogen disulfide and xanthogen polysulfide can be used. It may exist in some form.
  • the content ratio of the xanthogen compound (when the latex composition contains a plurality of xanthogen compounds, the content ratio of the total is 100 wt% of the carboxy modified polymer contained in the latex)
  • the amount is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, and still more preferably 0.5 to 5 parts by weight with respect to parts.
  • a vulcanization accelerator in addition to xanthogen compounds, compounds conventionally used as a vulcanization accelerator in the present invention, specifically, sulfur which causes the onset of symptoms of delayed allergy (Type IV)
  • a film-formed article such as a dip-formed product obtained after acting as a vulcanization accelerator (for example, a dithiocarbamate-based vulcanization accelerator, a thiazole-based vulcanization accelerator, etc.) containing It is preferable that the compound which remains in is substantially not contained.
  • the method of blending the xanthogen compound is not particularly limited as long as the latex of the carboxy-modified polymer and the xanthogen compound are finally mixed, and is not particularly limited.
  • the obtained latex of carboxy modified polymer is mixed with xanthogen compound in latex of carboxy modified polymer, and the solution or fine suspension of carboxy modified polymer dissolved or finely dispersed in organic solvent is xanthogen compound in advance.
  • the carboxy-modified polymer in which the xanthogen compound is blended is emulsified in water, and the organic solvent is optionally removed to obtain the carboxy-modified polymer in which the xanthogen compound is blended.
  • a latex of the carboxy modified polymer is obtained, and then a method of incorporating the xanthogen compound into the latex of the carboxy modified polymer is disclosed. preferable.
  • an activator is blended to the above-mentioned latex of the carboxy-modified polymer.
  • the carboxy-modified polymer in the latex composition is vulcanized with a sulfur-based vulcanizing agent using the latex composition obtained by adding an activating agent to the latex composition to dip
  • the activating agent acts as a vulcanization accelerator together with the xanthogen compound described above, and the activating agent itself crosslinks the carboxyl group of the carboxy-modified polymer as a crosslinking agent By acting, this further improves the tear strength of the film molded article such as the obtained dip molded article.
  • the metal compound is not particularly limited, and examples thereof include metal oxides and metal compounds containing at least one carbon atom.
  • the metal constituting the metal compound is not particularly limited, but a typical metal (Group 1 element, Group 2 element, Group 12 element, Group 13 element, Group 14 element, Group 15 element, Group 16) At least one element selected from the group consisting of an element, a group 17 element and a group 18 element) is preferable, and a group 2 element, a group 12 element, a group 13 element and a group 14 element are more preferable, Zinc, magnesium, calcium, aluminum and lead are more preferred, zinc, magnesium and calcium are particularly preferred, and zinc is most preferred. These metal compounds may be used alone or in combination of two or more.
  • the metal oxide is not particularly limited, but zinc oxide, magnesium oxide, titanium oxide, calcium oxide, lead oxide, iron oxide, from the viewpoint of further improving the tear strength of a film molded product such as a dip molded product to be obtained. Copper oxide, tin oxide, nickel oxide, chromium oxide, cobalt oxide and aluminum oxide are preferred, and zinc oxide is more preferred.
  • an organic metal compound is preferable from the viewpoint that the tear strength of a film molded product such as a dip molded product to be obtained is further improved.
  • carbonates, hydrogencarbonates and organic metal compounds are more preferred.
  • inorganic salts such as carbonates and hydrogen carbonates are particularly preferable from the viewpoint of excellent stability of the compound itself and excellent availability.
  • the content ratio of the activating agent in the latex composition used in the present invention is preferably 0.01 to 10 parts by weight, more preferably 0. 10 parts by weight with respect to 100 parts by weight of the carboxy-modified polymer contained in the latex composition. It is 1 to 5 parts by weight, more preferably 1 to 3 parts by weight.
  • the method of blending the activating agent may be any method as long as the latex of the carboxy-modified polymer and the activating agent are finally mixed, and is not particularly limited. After the latex of the carboxy modified polymer is obtained, there is a method of blending an activating agent with the latex of the carboxy modified polymer.
  • Sulfur-based vulcanizing agent In the preparation process of the present invention, a sulfur-based vulcanizing agent is added to the above-described carboxy-modified polymer latex in addition to the xanthogen compound and the activator.
  • the sulfur-based vulcanizing agent is not particularly limited.
  • sulfur such as powdery sulfur, sulfur dioxide, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur and the like; sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide And sulfur-containing compounds such as caprolactam disulfide (N, N'-dithio-bis (hexahydro-2H-azepinone-2)), phosphorus-containing polysulfides, polymeric polysulfides, and 2- (4'-morpholinodithio) benzothiazole It can be mentioned.
  • sulfur is preferably used.
  • the sulfur-based vulcanizing agent can be used singly or in combination of two or more.
  • the content of the sulfur-based vulcanizing agent is not particularly limited, but preferably 0.1 to 10 parts by weight, more preferably 0.2 to 3 parts by weight with respect to 100 parts by weight of the carboxy-modified polymer contained in the latex composition. It is a weight part.
  • Latex composition before ripening contains the latex of the carboxy-modified polymer described above, a xanthogen compound, an activator, and a sulfur-based vulcanizing agent. And the pH is less than 10.
  • a xanthogen compound, an activator, and a sulfur-based vulcanizing agent are mixed with the above-mentioned carboxy-modified polymer latex, and the pH is adjusted to less than 10 as necessary.
  • the latex composition before ripening thus obtained is aged by being stored for a half day (12 hours) to 14 days under the condition of a temperature of 5 to 60 ° C. Perform (pre-crosslinking).
  • the pH of the latex composition before aging may be less than 10 as described above, but is preferably 9.5 or less, more preferably 8.5 or less. If the pH of the latex composition before aging is too high, the tensile strength and tear strength of the resulting film molded article such as a dip molded article may be reduced.
  • the lower limit of the pH of the latex composition before aging is not particularly limited, but is preferably 6 or more, and more preferably 6.5 or more.
  • the latex composition of the present invention may be any one containing a latex of a carboxy-modified polymer, a xanthogen compound, an activating agent, and a sulfur-based vulcanizing agent.
  • the body may further contain a vulcanization accelerator as long as the onset of symptoms of delayed allergy (Type IV) can be suppressed.
  • vulcanization accelerator those commonly used in dip molding can be used, and examples thereof include diethyl dithiocarbamic acid, dibutyl dithiocarbamic acid, di-2-ethylhexyl dithiocarbamic acid, dicyclohexyl dithiocarbamic acid, diphenyl dithiocarbamic acid, and dibenzyl dithiocarbamic acid.
  • the latex composition of the present invention further comprises: antiaging agents; dispersing agents; reinforcing agents such as carbon black, silica and talc; fillers such as calcium carbonate and clay; UV absorbers; plasticizers; It can be blended as needed.
  • anti-aging agents examples include 2,6-di-4-methylphenol, 2,6-di-t-butylphenol, butylhydroxyanisole, 2,6-di-t-butyl- ⁇ -dimethylamino-p-cresol, Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2,2'-methylene-bis (6- ⁇ -methyl-benzyl-p-cresol), 4, Butylation of 4'-methylenebis (2,6-di-t-butylphenol), 2,2'-methylene-bis (4-methyl-6-t-butylphenol), alkylated bisphenols, p-cresol and dicyclopentadiene Reaction products, etc., sulfur-free phenolic anti-aging agents such as; 2,2'-thiobis- (4-methyl-6-t-butylpheno) ), 4,4'-thiobis- (6-t-butyl-o-cresol
  • the content of the antiaging agent is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the carboxy-modified polymer.
  • the method of mixing various compounding agents into the latex composition of the present invention is not particularly limited.
  • a latex of a carboxy-modified polymer, a xanthogen compound, an activator, and a sulfur-based vulcanizing agent After obtaining the latex composition before ripening to be contained, a method of mixing various compounding agents to be blended with the latex composition before ripening as needed, using a dispersing machine such as a ball mill, a kneader or a disper, After preparing an aqueous dispersion of compounding components other than the latex of the carboxy-modified polymer using the above-mentioned disperser, a method of mixing the aqueous dispersion with the latex of the carboxy-modified polymer may, for example, be mentioned. In addition, at least a part of the various compounding agents may be blended after aging.
  • the solids concentration of the latex composition of the present invention is preferably 10 to 60% by weight, more preferably 10 to 55% by weight.
  • the temperature at which the ripening is carried out may be 5 to 60 ° C., preferably 10 to 50 ° C., and more preferably 10 to 45 ° C. If the temperature for aging is too low, the effect of enhancing the mechanical properties of the resulting film molded article such as a dip molded article may be insufficient. On the other hand, if the temperature for aging is too high, the tensile strength of the resulting film-formed article such as a dip-formed article may be reduced.
  • the aging time depends on the aging temperature, but may be half a day (12 hours) to 14 days, preferably half a day (12 hours) to 10 days, and more preferably half a day (12 hours) to 7 days. If the aging time is too short, the effect of enhancing the mechanical properties of the resulting film molded article such as a dip molded article may be insufficient. On the other hand, if the aging time is too long, the tensile strength of the resulting film molded article such as a dip molded article may be lowered.
  • the pH of the latex composition after aging is preferably 6 or more and less than 10, and more preferably 6 to 9.
  • the pH of the latex composition after aging is preferably 6 or more and less than 10, and more preferably 6 to 9.
  • the pH of the latex composition tends to decrease due to aging. That is, the pH of the latex composition after aging tends to be lower than the pH of the latex composition before aging.
  • the pH of the latex composition after aging is preferably in the above range, but the pH of the latex composition after aging is in the above range and If not, the pH may be adjusted to the above-mentioned range by adding a pH adjuster to the matured latex composition.
  • a pH adjuster may be added to the latex composition after aging in order to make the pH more appropriate.
  • the pH adjuster to be added to the latex composition after aging is not particularly limited, but, for example, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; carbonates of alkali metals such as sodium carbonate and potassium carbonate And hydrogencarbonates of alkali metals such as sodium hydrogencarbonate; ammonia; organic amine compounds such as trimethylamine and triethanolamine; and the like, and hydroxides of alkali metals, ammonia and organic amine compounds are preferable.
  • These pH adjusters can be used alone or in combination of two or more.
  • the latex composition contains a latex of a carboxy-modified polymer, a xanthogen compound, an activator, and a sulfur-based vulcanizing agent, and has a pH of less than 10.
  • a latex of a carboxy-modified polymer a xanthogen compound, an activator, and a sulfur-based vulcanizing agent
  • a dip-formed body can be obtained by dip-forming the latex composition obtained by the above-mentioned production method of the present invention.
  • the mold In dip molding, the mold is immersed in a latex composition, the composition is deposited on the surface of the mold, then the mold is pulled out of the composition, and then the composition deposited on the surface of the mold is dried. is there.
  • the mold before being immersed in the latex composition may be preheated. Also, before immersing the mold in the latex composition, or after pulling up the mold from the latex composition, a coagulant can be used if desired.
  • the method of using the coagulant include a method of immersing the mold prior to immersion in the latex composition in a solution of the coagulant to attach the coagulant to the mold (anode adhesion immersion method), depositing the latex composition
  • anode adhesion immersion method There is a method of immersing the obtained mold in a coagulant solution (Tig condensation and immersion method) or the like, but the anode condensation and immersion method is preferable in that a dip-formed body with less thickness unevenness can be obtained.
  • the coagulant include metal halides such as barium chloride, calcium chloride, magnesium chloride, zinc chloride and aluminum chloride; nitrates such as barium nitrate, calcium nitrate and zinc nitrate; barium acetate, calcium acetate, zinc acetate etc
  • Water-soluble polyvalent metal salts such as salts; sulfates such as calcium sulfate, magnesium sulfate and aluminum sulfate; Among them, calcium salts are preferable, and calcium nitrate is more preferable.
  • These water-soluble polyvalent metal salts can be used alone or in combination of two or more.
  • the coagulant can usually be used as a solution of water, alcohol, or a mixture thereof, and is preferably used in the form of an aqueous solution.
  • the aqueous solution may further contain a water-soluble organic solvent such as methanol or ethanol or a nonionic surfactant.
  • concentration of the coagulant varies depending on the type of the water-soluble polyvalent metal salt, but is preferably 5 to 50% by weight, more preferably 10 to 30% by weight.
  • the mold After the mold is withdrawn from the latex composition, it is usually heated to dry the deposits formed on the mold.
  • the drying conditions may be selected appropriately.
  • Crosslinking of the dip-formed layer can be carried out usually by heat treatment at a temperature of 80 to 150 ° C., preferably for 10 to 130 minutes.
  • a heating method a method by external heating with infrared rays or heated air or internal heating with high frequency can be adopted. Among them, external heating by heating air is preferable.
  • the dip-formed layer is immersed in water, preferably warm water at 30 to 70 ° C.
  • water-soluble impurities eg, excess emulsifier, coagulant, etc.
  • the removal operation of the water-soluble impurities may be carried out after the dip molding layer is heat-treated, but it is preferable to be carried out before the heat treatment in that the water-soluble impurities can be removed more efficiently.
  • a dip molded body is obtained by desorbing a dip molding layer from the type
  • the desorption method it is possible to adopt a method of peeling off from the mold by hand or peeling by water pressure or pressure of compressed air. After desorption, heat treatment may be further performed at a temperature of 60 to 120 ° C. for 10 to 120 minutes.
  • the film thickness of the dip-formed product is preferably 0.03 to 0.50 mm, more preferably 0.05 to 0.40 mm, and particularly preferably 0.08 to 0.30 mm.
  • the dip-molded body obtained by the production method of the present invention is obtained by using the above-mentioned latex composition, it is possible to obtain tensile strength and tear strength while suppressing occurrence of symptoms of delayed allergy (Type IV).
  • Type IV delayed allergy
  • the film-formed body is a glove
  • the inorganic fine particles such as talc, calcium carbonate or the like, organic particles such as starch particles or the like are gloved in order to prevent adhesion on the contact surface of the film-formed bodies
  • the surface may be sprayed, an elastomer layer containing fine particles may be formed on the surface of the glove, or the surface layer of the glove may be chlorinated.
  • dip molded articles obtained by the production method of the present invention include nipples for baby bottles, syringes, tubes, water pillows, balloon sacks, catheters, medical supplies such as condoms, balloons, dolls, balls, etc.
  • Industrial products such as pressure-molding bags, gas storage bags, and the like;
  • Adhesive Composition In the present invention, the latex composition obtained by the above-mentioned production method of the present invention can be used as an adhesive composition.
  • the content (solid content) of the latex composition in the adhesive composition is preferably 5 to 60% by weight, more preferably 10 to 30% by weight.
  • the adhesive composition preferably comprises an adhesive resin in addition to the above-described latex composition.
  • the adhesive resin is not particularly limited.
  • resorcinol-formaldehyde resin, melamine resin, epoxy resin and isocyanate resin can be suitably used, and among these, resorcinol-formaldehyde resin is preferable.
  • the resorcinol-formaldehyde resin known ones (for example, those disclosed in JP-A-55-142635) can be used.
  • the reaction ratio of resorcin to formaldehyde is usually 1: 1 to 1: 5, preferably 1: 1 to 1: 3, in terms of a molar ratio of "resorcin: formaldehyde".
  • the adhesive composition may be a conventionally used 2,6-bis (2,4-dihydroxyphenylmethyl) -4-chlorophenol or the like.
  • Compounds, isocyanates, blocked isocyanates, ethylene ureas, polyepoxides, modified polyvinyl chloride resins and the like can be contained.
  • the adhesive composition can contain a vulcanization aid.
  • the incorporation of the vulcanization aid can improve the mechanical strength of the composite to be described later obtained using the adhesive composition.
  • Vulcanization aids include quinone dioximes such as p-quinone dioxime; methacrylic acid esters such as lauryl methacrylate and methyl methacrylate; DAF (diallyl fumarate), DAP (diallyl phthalate), TAC (triallyl cyanurate), And allyl compounds such as TAIC (triaryl isocyanurate); maleimide compounds such as bismaleimide, phenyl maleimide, N, N-m-phenylene dimaleimide; sulfur; and the like.
  • Adhesive Layer-Forming Substrate According to the production method of the present invention, the latex composition obtained by the production method of the present invention described above or the adhesive layer formed using the adhesive composition obtained using the same An adhesive layer forming base material can be obtained by forming on the base material surface.
  • a fiber base material can be used.
  • the type of fiber constituting the fiber base is not particularly limited, and examples thereof include vinylon fiber, polyester fiber, nylon, polyamide fiber such as aramid (aromatic polyamide), glass fiber, cotton, rayon and the like. These can be suitably selected according to the use.
  • the shape of the fiber substrate is not particularly limited, and examples thereof include staples, filaments, cords, ropes, woven fabrics (such as canvas), and the like, and can be appropriately selected according to the use.
  • the adhesive layer-forming substrate can be used as a substrate-rubber composite by adhering to rubber through the adhesive layer.
  • the base material-rubber composite is not particularly limited. For example, rubber using a cored rubber toothed belt using cords as a fiber base, rubber using a base cloth-like fiber base such as canvas A toothed belt etc. may be mentioned.
  • the method for obtaining the base material-rubber complex is not particularly limited.
  • the adhesive composition is attached to the base material by immersion treatment or the like to obtain an adhesive layer forming base material, and the adhesive layer forming base material is obtained Is placed on rubber and heated and pressurized.
  • Pressurization can be performed using a compression (press) molding machine, a metal roll, an injection molding machine, or the like.
  • the pressure of pressurization is preferably 0.5 to 20 MPa, more preferably 2 to 10 MPa.
  • the heating temperature is preferably 130 to 300 ° C., more preferably 150 to 250 ° C.
  • the heat and pressure treatment time is preferably 1 to 180 minutes, more preferably 5 to 120 minutes.
  • a base material-rubber-base material complex can be mentioned.
  • the substrate-rubber-substrate composite can be formed, for example, by combining a substrate (which may be a composite of two or more substrates) and a substrate-rubber composite. Specifically, a core wire as a base material, a rubber and a base fabric as a base material are overlapped (in this case, an adhesive composition is appropriately attached to the core wire and base cloth to be used as an adhesive layer forming base material) By applying pressure while heating, a substrate-rubber-substrate composite can be obtained.
  • the substrate-rubber composite using the adhesive layer-forming substrate obtained by the production method of the present invention is excellent in mechanical strength, abrasion resistance and water resistance, and therefore flat belts, V-belts,
  • the belt can be suitably used as a V-ribbed belt, a round belt, a square belt, a toothed belt or the like.
  • a base material-rubber complex obtained using the adhesive layer-forming base material obtained by the production method of the present invention is excellent in oil resistance and can be suitably used as a belt-in-oil belt.
  • the substrate-rubber composite obtained by using the adhesive layer-formed substrate of the present invention can be suitably used as a hose, a tube, a diaphragm and the like.
  • hose examples include single-pipe rubber hoses, multilayer rubber hoses, knitted reinforcement hoses and cloth wound reinforcement hoses.
  • a diaphragm a flat diaphragm, a rolling diaphragm, etc. are mentioned.
  • the base material-rubber complex using the adhesive layer forming base material obtained by the manufacturing method of the present invention can be used as industrial products such as a seal, a rubber roll, etc. besides the above applications.
  • the seals include moving site seals such as for rotation, swinging, and reciprocating, and fixed site seals.
  • Examples of the motion site seal include an oil seal, a piston seal, a mechanical seal, a boot, a dust cover, a diaphragm, an accumulator, and the like.
  • An O-ring, various gaskets, etc. are mentioned as a fixed part seal.
  • Examples of rubber rolls include rolls that are parts of OA equipment such as printing equipment and copying equipment; rolls for fiber processing such as stretching rolls for spinning and draft rolls for spinning; rolls for iron making such as bridle rolls, snubber rolls, steering rolls, etc. It can be mentioned.
  • the carboxy-modified polymer constituting the latex of the carboxy-modified polymer was subjected to 1 H-NMR measurement to determine the number of carboxyl groups in the carboxy-modified polymer. Next, based on the number of carboxyl groups determined, the modification ratio of the carboxyl group-containing compound was determined according to the following formula (i).
  • Modification rate (mol%) (X / Y) ⁇ 100 (i)
  • X represents the number of carboxyl groups in the carboxy-modified polymer
  • Y represents the total number of monomer units of the carboxy-modified polymer ((weight-average molecular weight of the carboxy-modified polymer (Mw)) / (Average molecular weight according to the content ratio of each monomer unit which comprises a carboxy modified polymer) is represented, respectively.
  • Production Example 1 Production of latex of carboxy-modified synthetic polyisoprene (A-1) Synthetic polyisoprene having a weight-average molecular weight of 1,300,000 (trade name "NIPOL IR 2200L", manufactured by Nippon Zeon Co., homopolymer of isoprene, cis-binding unit 98%) is mixed with cyclohexane and dissolved while raising the temperature to 60 ° C. with stirring, and a cyclohexane solution (a) of synthetic polyisoprene having a viscosity of 12,000 mPa ⁇ s measured by a B-type viscometer Adjusted (solids concentration 8% by weight).
  • A-1 Synthetic polyisoprene having a weight-average molecular weight of 1,300,000 (trade name "NIPOL IR 2200L", manufactured by Nippon Zeon Co., homopolymer of isoprene, cis-binding unit 98%) is mixed with
  • an anionic surfactant aqueous solution (b) having a concentration of 1.5% by weight 20 parts of sodium rosin acid was added to water, and the temperature was raised to 60 ° C. for dissolution to prepare an anionic surfactant aqueous solution (b) having a concentration of 1.5% by weight.
  • a mixer (trade name “Multi-line mixer MS26-MMR-5” is used so that the above cyclohexane solution (a) and the above anionic surfactant aqueous solution (b) have a weight ratio of 1: 1.5. .5 L "(manufactured by Satake Chemical Engineering Co., Ltd.), followed by mixing and emulsifying at a rotational speed of 4100 rpm using an emulsifying apparatus (trade name” Milder MDN 310 ", manufactured by Pacific Kiko Co., Ltd.) Liquid (c) was obtained.
  • an emulsifying apparatus (trade name” Milder MDN 310 ", manufactured by Pacific Kiko Co., Ltd.) Liquid (c) was obtained.
  • the total feed flow rate of the cyclohexane solution (a) and the anionic surfactant aqueous solution (b) was 2,000 kg / hr, the temperature was 60 ° C., and the back pressure (gauge pressure) was 0.5 MPa.
  • the emulsion (c) is heated to 80 ° C. under a reduced pressure of -0.01 to -0.09 MPa (gauge pressure), cyclohexane is distilled off, and an aqueous dispersion (d) of synthetic polyisoprene is obtained. Obtained.
  • an antifoaming agent (trade name "SM 5515", manufactured by Toray Dow Corning Co., Ltd.) was continuously added while spraying so that the amount was 300 ppm by weight with respect to the synthetic polyisoprene in the emulsion (c). .
  • SM 5515 manufactured by Toray Dow Corning Co., Ltd.
  • the obtained aqueous dispersion (d) of synthetic polyisoprene is subjected to 4,000 to 500 using a continuous centrifuge (trade name "SRG510", manufactured by Alfa Laval).
  • the mixture was centrifuged at 5,000 G to obtain a latex (e) of synthetic polyisoprene having a solid concentration of 56% by weight as a light liquid.
  • the conditions for centrifugation were 10% by weight solid concentration of the aqueous dispersion (d) before centrifugation, the flow rate during continuous centrifugation was 1300 kg / hr, and the back pressure (gauge pressure) of the centrifuge was 1. It was 5 MPa.
  • the obtained latex (e) of synthetic polyisoprene had a solid concentration of 60% by weight.
  • a latex (e) of synthetic polyisoprene to which a dispersant was added was charged in a nitrogen-substituted reaction container equipped with a stirrer, and the temperature was raised to 30 ° C. while stirring. Further, using another container, 3 parts of methacrylic acid as a carboxyl group-containing compound and 16 parts of distilled water were mixed to prepare a methacrylic acid diluted solution. The methacrylic acid diluted solution was added over 30 minutes into a reaction vessel heated to 30 ° C.
  • the carboxy-modified synthetic polyisoprene (A-1) was concentrated by a centrifuge to obtain a light solution with a solid concentration of 56%. Then, with respect to the obtained latex of the carboxy-modified synthetic polyisoprene (A-1), the modification ratio by the carboxyl group-containing compound was measured according to the above method, and the modification ratio was 0.5 mol%.
  • Production Example 2 Production of Latex of Carboxy-Modified Synthetic Polyisoprene (A-2)
  • a carboxy-modified synthetic polyisoprene having a solid concentration of 55% was prepared in the same manner as in Production Example 1 except that the amount of methacrylic acid used was changed from 3 parts to 5 parts.
  • a latex of (A-2) was obtained.
  • the obtained latex of the carboxy-modified synthetic polyisoprene (A-2) was measured for the degree of modification with a carboxyl group-containing compound according to the above-mentioned method, and the degree of modification was 1 mol%.
  • Example 1 Preparation of Latex Composition First, using sodium hydroxide, a styrene-maleic acid mono-sec-butyl ester-maleic acid monomethyl ester polymer (trade name "Scripset 550", manufactured by Hercules) was treated with sodium hydroxide to form carboxyl groups in the polymer. After 100% neutralization, an aqueous solution of sodium salt (concentration 10% by weight) was prepared. Then, this sodium salt aqueous solution was added to the latex of the carboxy-modified synthetic polyisoprene (A-1) obtained in Production Example 1 with respect to 100 parts of the carboxy-modified synthetic polyisoprene (A-1) in a solid content conversion of 0. The mixture was added to make 8 parts to obtain a mixture.
  • a styrene-maleic acid mono-sec-butyl ester-maleic acid monomethyl ester polymer (trade name "Scripset 550", manufactured by Hercules) was treated with sodium hydroxide to form
  • each combination agent so that it will become 1.5 parts of zinc oxide as an activator, 1.5 parts of sulfur, and 2 parts of antioxidants (brand name "Wingstay L", Goodyear company make) in conversion of solid content.
  • Water dispersion was added to obtain a latex composition.
  • the pH of the obtained latex composition was adjusted to 7.0 by adding an aqueous potassium hydroxide solution (concentration 5.0% by weight) as a pH adjuster (the pH of the latex composition before aging was 7). .0).
  • the obtained latex composition was aged in a constant temperature water bath adjusted to 30 ° C. for 48 hours.
  • the pH of the latex composition after aging was 6.7.
  • a commercially available ceramic hand mold (made by Shinko Co., Ltd.) was washed and preheated in an oven at 70 ° C., then 18 wt% calcium nitrate and 0.05 wt% polyoxyethylene lauryl ether ( It was immersed in an aqueous coagulant solution containing trade name "Emulgen 109P" (manufactured by Kao Corporation) for 5 seconds, and was taken out from the aqueous coagulant solution. Next, the hand mold was dried in an oven at 70 ° C. for 30 minutes or more to attach a coagulant to the hand mold, and the hand mold was coated with the coagulant.
  • the coagulant-coated hand was then removed from the oven and dipped in the aged latex composition described above for 10 seconds. Then, the hand mold was air-dried at room temperature for 10 minutes, and then immersed in warm water of 60 ° C. for 5 minutes to elute water-soluble impurities to form a dip mold layer in the hand mold. Thereafter, the dip-formed layer formed in the hand mold is crosslinked by heating in an oven at a temperature of 130 ° C. for 30 minutes, cooled to room temperature, sprayed with talc, and peeled from the hand mold, A dip molded body (rubber glove) was obtained. And each evaluation of tear strength and tensile strength was performed according to the said method about the obtained dip molding body (rubber glove). The results are shown in Table 1. In Table 1, the blending amount of the dispersant is described with respect to 100 parts of the synthetic polyisoprene before the carboxy modification.
  • Example 2 The latex composition as in Example 1, except that the pH of the latex composition before ripening is set to 8.0 by adjusting the addition amount of the pH adjuster (potassium hydroxide aqueous solution) to the latex composition before ripening Products and dip molded articles (rubber gloves) were produced and evaluated in the same manner.
  • the pH of the latex composition after aging was 7.5. The results are shown in Table 1.
  • Example 3 The latex composition is the same as in Example 1 except that the pH of the latex composition before ripening is set to 9.5 by adjusting the addition amount of the pH adjuster (potassium hydroxide aqueous solution) to the latex composition before ripening. Products and dip molded articles (rubber gloves) were produced and evaluated in the same manner. The pH of the latex composition after aging was 8.5. The results are shown in Table 1.
  • the pH adjuster potassium hydroxide aqueous solution
  • Example 4 A latex of carboxy-modified synthetic polyisoprene (A-2) obtained in Production Example 2 (carboxy-modified synthetic polyisoprene (A), instead of the latex of carboxy-modified synthetic polyisoprene (A-1) obtained in Production Example 1 2) Using 100 parts in terms of conversion, and further adjusting the amount of pH adjuster (potassium hydroxide aqueous solution) added to the latex composition before ripening, the pH of the latex composition before ripening is 9. A latex composition and a dip-formed product (rubber gloves) were produced in the same manner as in Example 1 except that No. 5 was used, and evaluations were made in the same manner. The pH of the latex composition after aging was 8.5. The results are shown in Table 1.
  • Comparative Example 1 The latex composition as in Example 1, except that the pH of the latex composition before ripening was 12.0 by adjusting the amount of the pH adjuster (potassium hydroxide aqueous solution) added to the latex composition before ripening. Products and dip molded articles (rubber gloves) were produced and evaluated in the same manner. The pH of the latex composition after aging was 9.5. The results are shown in Table 1.
  • Comparative example 2 When preparing a latex composition, aging is performed by not adding zinc diisopropyl xanthate as a xanthogen compound, and further adjusting the amount of pH adjuster (potassium hydroxide aqueous solution) added to the latex composition before aging.
  • a latex composition and a dip-molded product (rubber glove) were produced in the same manner as in Example 1 except that the pH of the previous latex composition was changed to 9.5, and evaluations were made in the same manner.
  • the pH of the latex composition after aging was 9.5. The results are shown in Table 1.
  • a latex composition containing a latex of a carboxy-modified polymer, a xanthogen compound, an activating agent, and a sulfur-based vulcanizing agent, and having a pH before aging of less than 10, is used as the latex composition.
  • the resulting dip-formed body was excellent in tear strength and tensile strength (Examples 1 to 4).
  • the dip molded article obtained when the latex composition is ripened and then formed into a dip-molded article has tear strength and tensile strength.
  • the dip-molded product produced using the obtained latex composition was inferior in tear strength and tensile strength (Comparative Example 2).

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Abstract

L'invention fournit un procédé de fabrication de composition de latex qui comporte une étape de préparation au cours de laquelle est préparée une composition de latex qui comprend un latex de polymère modifié par carboxy, un agent de vulcanisation à base de soufre, un composé xanthogène et un activateur, et qui présente un pH inférieur à 10 ; et une étape de maturation au cours de laquelle ladite composition de latex est soumise à une maturation par stockage pendant une demie journée à 14 jours dans des conditions de température comprises entre 5 et 60°C.
PCT/JP2018/029955 2017-09-22 2018-08-09 Procédé de fabrication de composition de latex WO2019058807A1 (fr)

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WO2021166724A1 (fr) * 2020-02-20 2021-08-26 日本ゼオン株式会社 Procédé de fabrication de composition de latex
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