JP6214865B2 - Rubber-modified thermoplastic elastomer - Google Patents

Description

  The present invention relates to a rubber-modified thermoplastic elastomer having low adhesiveness and high softness, and a thermoplastic resin composition containing the rubber-modified thermoplastic elastomer and another thermoplastic resin.

  In recent years, examples of elastomers used in the fields of automobiles, home appliances, OA equipment, building materials, etc. include PVC, styrene, urethane, and olefin. Among them, PVC-based elastomers are widely used, but it is necessary to add a large amount of plasticizer in order to impart softness, and there are problems such as heat loss, and dioxins may be generated during incineration. is there. In addition, in the styrene-based elastomer, there are elastomers having segments such as isoprene, butadiene, and acrylate as a soft component, but a block copolymer having a hard segment and a soft segment requires a special polymerization method, There was a disadvantage that it was inferior in economic efficiency. As the urethane-based elastomer, thermoplastic polyurethane is used, but there is a disadvantage that it is inferior in moisture resistance. Olefin-based elastomers have a problem of low polarity and poor surface decorating properties such as painting and printing.

  Regarding styrene elastomers other than block copolymers, JP-A-8-27336 (Patent Document 1) describes a copolymer having a glass transition temperature of 20 ° C. or lower and a styrene resin having a heat distortion temperature of 95 ° C. or higher. The thermoplastic resin composition which consists of these is mentioned. Japanese Patent Application Laid-Open No. 2000-169656 (Patent Document 2) discloses that a soft resin composed of a (meth) acrylic acid ester copolymer, a styrene copolymer, and a graft copolymer can be used to provide softness. It is described that it is possible to obtain a soft building material component that is high, has low adhesiveness at high temperatures, and is excellent in shape retention during heating. However, in these compositions or soft parts for building materials, there is a problem that when high softness is required, the adhesiveness becomes large, and the balance between softness and adhesiveness cannot be satisfied.

JP-A-8-27336

JP 2000-169656 A

  An object of the present invention is to provide a rubber-modified thermoplastic elastomer having low tackiness and high softness, and a rubber-modified thermoplastic elastomer composition containing the rubber-modified thermoplastic elastomer and other thermoplastic resins.

  As a result of intensive studies on the solution of the above problems, the present inventors have found that a rubber-modified thermoplastic elastomer having a specific rubber content, a graft ratio and a storage elastic modulus provides an excellent balance between adhesiveness and softness. The present invention has been reached.

That is, in the present invention, in the presence of 70 to 95 parts by weight of the rubber-like polymer, the aromatic vinyl monomer and other vinyl monomers that can be copolymerized with the aromatic vinyl monomer 5 to 30 are used. A rubber-modified thermoplastic elastomer (A) obtained by graft polymerization of parts by weight, having a graft ratio of 7 to 35%, and a storage elastic modulus of acetone insolubles of 0.5 to 40 MPa, and others A rubber-modified thermoplastic elastomer composition containing the thermoplastic resin (B), wherein the content of the rubber-like polymer component in the composition is 80 to 95% by weight. The present invention relates to a rubber-modified thermoplastic elastomer composition obtained from a plastic elastomer composition.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a rubber-modified thermoplastic elastomer having low adhesiveness and high softness, and a rubber-modified thermoplastic elastomer composition containing the rubber-modified thermoplastic elastomer and other thermoplastic resins.

The present invention will be described in detail below.
The rubber-modified thermoplastic elastomer (A) of the present invention is grafted with an aromatic vinyl monomer and another vinyl monomer copolymerizable with the aromatic vinyl monomer in the presence of a rubber-like polymer. It is a copolymer elastomer obtained by polymerization.

  The rubbery polymer used in the present invention includes polybutadiene rubber, styrene-butadiene rubber (SBR), styrene-butadiene-styrene (SBS) block copolymer, styrene- (ethylene-butadiene) -styrene (SEBS) block copolymer, Diene rubbers such as acrylonitrile-butadiene rubber (NBR), butyl acrylate-butadiene, butyl acrylate rubber, butadiene-butyl acrylate rubber, 2-ethylhexyl acrylate-butyl acrylate rubber, 2-ethylhexyl methacrylate-butyl acrylate rubber, acrylic acid Acrylic rubbers such as stearyl-butyl acrylate rubber, polyorganosiloxane-butyl acrylate composite rubber, and other polyolefins such as ethylene-propylene rubber, ethylene-propylene-diene rubber Fin-based rubber, silicone rubber such as polyorganosiloxane rubber and the like, which can be used singly or in combination. In particular, polybutadiene rubber, styrene-butadiene rubber, butyl acrylate rubber, and ethylene-propylene-diene rubber are preferable.

  Although there is no restriction | limiting in particular in the weight average particle diameter of a rubber-like polymer, It is preferable that it is 0.05-1.0 micrometer from a viewpoint of the balance of softness and adhesiveness, and it is 0.1-0.6 micrometer. It is more preferable. In addition, a known method can be used to adjust the weight average particle size of the rubbery polymer, but a rubbery polymer having a relatively small particle size is produced in advance, and the target weight average particle size is increased by agglomeration. It is also possible to use an agglomerated and enlarged rubber-like polymer.

  The rubber-modified thermoplastic elastomer (A) of the present invention needs to contain 70 to 95 parts by weight of a rubbery polymer per 100 parts by weight of the rubber-modified thermoplastic elastomer (A). If the amount is less than 70 parts by weight, the softness of the rubber-modified thermoplastic elastomer (A) is inferior. When it exceeds 95 parts by weight, the rubber-modified thermoplastic elastomer (A) has poor adhesion. Preferably it is 75 weight part-90 weight part.

  Examples of the aromatic vinyl monomer constituting the rubber-modified thermoplastic elastomer (A) include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methyl-p-methyl. Examples thereof include styrene, halogenated styrene, ethyl styrene, p-isopropyl styrene, pt-butyl styrene, 2,4-dimethyl styrene, divinyl benzene and the like, and one or more can be used. As the aromatic vinyl monomer, styrene, α-methylstyrene, and p-methylstyrene are particularly preferable.

  Other vinyl monomers that can be copolymerized with aromatic vinyl monomers include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, methyl (meth) acrylate, and ethyl (meth) acrylate. , (Meth) acrylate monomers such as butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, maleimides such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide Examples of the monomer include one or two or more. As other vinyl monomers, acrylonitrile, methyl (meth) acrylate, and N-phenylmaleimide are particularly preferable.

  There is no particular limitation on the composition ratio of the above-mentioned monomer that is graft-polymerized with the rubber-like polymer, but the aromatic vinyl monomer is 50 to 90% by weight, and other vinyl monomers that can be copolymerized are 10 to 10%. The composition ratio is preferably 50% by weight, more preferably 60 to 80% by weight of an aromatic vinyl monomer, and more preferably 20 to 40% by weight of another copolymerizable vinyl monomer.

  There is no restriction | limiting in particular about the polymerization method of the rubber modified thermoplastic elastomer (A) of this invention, Although it can manufacture by emulsion polymerization, suspension polymerization, block polymerization, solution polymerization, or these combination, it manufactures by emulsion polymerization. Things are preferable.

  Examples of the polymerization initiator used when polymerizing the rubber-modified thermoplastic elastomer (A) include benzoyl peroxide, lauroyl peroxide, t-butyl peroxypivalate, t-butyl peroxybenzoate, and t-butyl peroxyiso. Organic peroxides such as butyrate, t-butyl peroxy octoate, cumyl peroxy octoate, 1,1-bis (t-butyl peroxy) 3,3,5-trimethylcyclohexane, 2,2-azobis An azo compound such as isobutyronitrile, 2,2-azobis (2-methylbutyronitrile), 2,2-azobis (2,4-dimethylvaleronitrile) can be used. In particular, the use of organic peroxides is preferable. Among them, t-butyl peroxypivalate, t-butyl peroxyoctoate, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane are particularly preferable. Is preferred. Although there is no restriction | limiting in particular in the quantity of the polymerization initiator used for superposition | polymerization, 0.001-5.0 weight part is with respect to 100 weight part of total amounts of the rubber-like polymer used for superposition | polymerization, and a vinyl-type monomer. Used in a range.

  When polymerizing the rubber-modified thermoplastic elastomer (A), a hydrocarbon solvent can be used as necessary. Examples of hydrocarbon solvents include saturated hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane, cycloheptane, and unsaturated hydrocarbons such as pentene, hexene, heptene, cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene, and 1-methylcyclohexene. Hydrocarbon compounds such as hydrocarbons, aromatic hydrocarbons such as benzene, toluene, and xylene. In particular, cyclohexene and toluene, which have a moderately low boiling point and can be easily recovered and reused by steam distillation after the completion of polymerization, are preferable from the viewpoint of environmental problems, although they are different from the object of the present invention. It is used in the range of 0 to 50 parts by weight with respect to 100 parts by weight of the total amount of the rubbery polymer and vinyl monomer used for polymerization.

  It is also possible to use a chain transfer agent as necessary. Examples of the chain transfer agent include alkyl mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan, xanthogen compounds such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, Thiuram compounds such as tetramethylthiuram monosulfide, phenol compounds such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol, allyl compounds such as allyl alcohol, dichloromethane, dibromomethane, tetrabromide Halogenated hydrocarbon compounds such as carbon, vinyl ethers such as α-benzyloxystyrene, α-benzyloxyacrylonitrile, α-benzyloxyacrylamide, and triphenyl Examples include ethane, pentaphenylethane, acrolein, metaacrolein, thioglycolic acid, thiomalic acid, 2-ethylhexyl thioglycolate, terpinolene, α-methylstyrene dimer, and the like, and one or more of these can be used. . It is used in the range of 0 to 5 parts by weight with respect to 100 parts by weight of the total amount of the rubbery polymer and the diene monomer.

  The graft ratio of the rubber-modified thermoplastic elastomer (A) of the present invention needs to be 4 to 35%. When the graft ratio is less than 4%, the rubber-modified thermoplastic elastomer (A) has poor adhesiveness. When the graft ratio exceeds 35%, the softness of the rubber-modified thermoplastic elastomer (A) is inferior. Preferably, it is 7 to 30%.

  The graft ratio of the rubber-modified thermoplastic elastomer (A) is the amount of the copolymer component that is directly grafted to the rubber-like polymer with respect to the amount of the rubber-like polymer in the rubber-modified thermoplastic elastomer (A). Say percentage. This graft ratio can be controlled by changing the polymerization initiator amount, polymerization temperature, chain transfer agent amount, and the like.

The graft ratio can be determined by the following method. 3 g of the rubber-modified thermoplastic elastomer (A) is put into 100 ml of acetone at room temperature and stirred sufficiently, and then centrifuged to remove acetone-soluble components. Then, it dries and calculates | requires an insoluble part (W). On the other hand, the amount of the rubber-like polymer in the insoluble matter (W) can be calculated based on the rubber-like polymer used for the polymerization. With the calculated amount of the rubbery polymer as R, the graft ratio is obtained from the following formula.
Graft ratio (%) = [(W−R) / R] × 100

  The storage elastic modulus of the rubber-modified thermoplastic elastomer (A) of the present invention in the acetone-insoluble portion needs to be 0.5 to 40 MPa. When the storage elastic modulus is less than 0.5 MPa, the rubber-modified thermoplastic elastomer (A) has poor adhesion, and when it exceeds 40 MPa, the rubber-modified thermoplastic elastomer (A) has poor flexibility. From the viewpoint of the balance between adhesiveness and softness, the storage elastic modulus is preferably 1 to 35 MPa, and more preferably 3 to 30 MPa.

  The storage elastic modulus of the rubber-modified thermoplastic elastomer (A) in the acetone-insoluble portion can be adjusted by appropriately selecting the amount of polymerization initiator, the polymerization temperature, the amount of chain transfer agent, and the gel content of the rubbery polymer. For example, if the amount of the chain transfer agent used in the polymerization of the rubber-modified thermoplastic elastomer (A) is increased, the storage elastic modulus in the acetone-insoluble matter is reduced, and if the gel content of the rubber-like polymer is increased, the storage in the acetone-insoluble matter is reduced. The elastic modulus increases. Further, when the graft ratio of the rubber-modified thermoplastic elastomer (A) is small, the storage elastic modulus is small, and when the graft ratio is large, the storage elastic modulus is also large.

  The method for obtaining the storage elastic modulus of the rubber-modified thermoplastic elastomer (A) in the acetone insoluble matter is as follows. 6 g of the rubber-modified thermoplastic elastomer (A) was put into 200 ml of acetone at room temperature and sufficiently stirred, and then centrifuged to remove acetone-soluble components. The obtained acetone insoluble matter was vacuum-dried to remove acetone, and then melt-pressed to prepare a sheet having a thickness of 1 mm. This sheet was cut into a strip shape having a length of 40 mm and a width of 5 mm to obtain a test piece. As a measuring device, Rhegel E-4000 manufactured by UBM Co., Ltd. is used, and the storage modulus is measured by measuring the test piece at a frequency of 1 Hz with the measurement temperature being constant at 30 ° C. and the measurement mode being the fixed end bending mode. did.

  In the present invention, other thermoplastic resins (B) can be used in addition to the rubber-modified thermoplastic elastomer (A). However, when other thermoplastic resin (B) is used, it is necessary that the rubber-like polymer contained in the rubber-modified thermoplastic elastomer composition is 70 to 95% by weight. If the amount is less than 70% by weight, the softness of the composition is inferior.

  Other thermoplastic resins (B) used in the present invention include, for example, styrene resins such as ABS resin, AES resin, ASA resin, AS resin, HIPS and PS whose rubbery polymer content is less than 70% by weight. Resins, olefin resins such as polyethylene and polypropylene, polyamide resins such as PA6, PA66, PA46 and PA12, polyester resins such as polybutylene terephthalate, polyethylene terephthalate and polyarylate, polycarbonate resins, polyphenylene ether resins, polymethyl methacrylate, Examples thereof include methacrylic resins such as polyethyl methacrylate, polylactic acid resins, polyacetals, vinyl chloride resins, and the like, and these can be used alone or in combination of two or more.

  As the other thermoplastic resin (B), from at least two groups selected from the group of aromatic vinyl monomers, vinyl cyanide monomers, (meth) acrylic acid esters, and maleimide monomers. In the case of using a copolymer obtained by copolymerizing the monomer, a reduced viscosity of the copolymer (0.4 g / 100 cc, using N, N dimethylformamide as a solvent at 30 ° C. from the viewpoint of tackiness. Measurement) is preferably 0.2 to 1.2 dl / g, and more preferably 0.25 to 1.0 dl / g.

  Other thermoplastic resin (B) is selected from the group of aromatic vinyl monomers, vinyl cyanide monomers, (meth) acrylic acid esters and maleimide monomers in the presence of rubbery polymers. In the case of using a rubber-modified thermoplastic resin obtained by graft copolymerization of a monomer composed of at least two kinds of groups and having a rubber-like polymer content of less than 50% by weight, an adhesive viewpoint The reduced viscosity (measured at 30 ° C. using N, N dimethylformamide as a solvent) of the acetone soluble part of the rubber-modified thermoplastic resin is preferably 0.2 to 1.0 dl / g. 0.25 to 0.5 dl / g is more preferable.

  The rubber-modified thermoplastic elastomer (A) and the rubber-modified thermoplastic elastomer composition of the present invention are a hindered amine-based light stabilizer, a hindered phenol-based, a sulfur-containing organic compound-based, if necessary, as long as the purpose is not impaired. , Antioxidants such as phosphorus-containing organic compounds, heat stabilizers such as phenols and acrylates, benzoate, benzotriazole, benzophenone, salicylate UV absorbers, organic nickel, higher fatty acid amides, etc. Flame retardants and flame retardant aids such as lubricants, plasticizers such as phosphate esters, polybromophenyl ether, tetrabromobisphenol A, brominated epoxy oligomers, halogen-containing compounds such as bromine compounds, phosphorus compounds, and antimony trioxide Agent, odor masking agent, carbon black, titanium oxide, pigment That the addition of such fine dye can be. Furthermore, reinforcing agents and fillers such as talc, calcium carbonate, aluminum hydroxide, glass fibers, glass flakes, glass beads, carbon fibers, and metal fibers can be added.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” and “%” are based on weight unless otherwise specified.

Production of butyl acrylate rubber latex (a-1) In a nitrogen-replaced glass reactor, 180 parts by weight of deionized water, 15 parts by weight of butyl acrylate, 0.1 part by weight of allyl methacrylate, 0.06 part by weight of dipotassium alkenyl succinate (Solid content conversion) 0.15 parts by weight of potassium persulfate was charged and reacted at 65 ° C. for 1 hour. Thereafter, an emulsifier aqueous solution in which 0.24 parts by weight of dipotassium alkenyl succinate (in terms of solid content) was dissolved in 85 parts by weight of butyl acrylate and 0.53 parts by weight of allyl methacrylate and 20 parts by weight of deionized water for 3 hours. Over time. After dropping, the mixture was held for 3 hours to obtain butyl acrylate rubber latex (a-1). The weight average particle diameter of the butyl acrylate rubber latex (a-1) was 0.15 μm, and the gel content was 90%.

Production of Styrene-Butadiene Rubber Latex (a-2) After replacing the inside of a 10-liter pressure vessel with nitrogen, 95 parts by weight of 1,3-butadiene, 5 parts by weight of styrene, 0.5 parts by weight of n-dodecyl mercaptan, excess 0.3 parts by weight of potassium sulfate, 1.8 parts by weight of disproportionated sodium rosinate, 0.1 parts by weight of sodium hydroxide and 145 parts by weight of deionized water were charged and reacted at 70 ° C. for 8 hours while stirring. Thereafter, 0.2 parts by weight of disproportionated sodium rosinate, 0.1 parts by weight of sodium hydroxide and 5 parts by weight of deionized water were added. Further, stirring was continued for 6 hours while maintaining the temperature at 70 ° C. to complete the reaction. Thereafter, the remaining 1,3-butadiene was removed under reduced pressure to obtain a styrene-butadiene rubber latex (a-2). The weight average particle diameter of the styrene-butadiene rubber latex (a-2) was 0.2 μm, and the gel content was 80%.

Production of Rubber Modified Thermoplastic Elastomer (A-1) A glass reactor was charged with 150 parts by weight of deionized water and 85 parts by weight (solid content) of styrene-butadiene rubber latex (a-2), and nitrogen substitution was performed. After nitrogen substitution, when the temperature inside the tank was reached and reached 60 ° C., 0.4 part by weight of lactose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. An aqueous solution dissolved in was added. An emulsifier obtained by dissolving 1.0 part by weight of potassium oleate in a mixed solution of 4 parts by weight of acrylonitrile, 11 parts by weight of styrene, 0.15 part by weight of t-butyl hydroperoxide and 16 parts by weight of deionized water after reaching 65 ° C. The aqueous solution was continuously added dropwise over 3 hours. After dripping, it was kept for 3 hours to obtain a latex of rubber-modified thermoplastic elastomer (A-1). Then, powder of rubber-modified thermoplastic elastomer (A-1) was obtained by salting out, dehydrating and drying. The graft ratio of the rubber-modified thermoplastic elastomer (A-1) was 15%, and the storage elastic modulus in the acetone insoluble part was 6.3 MPa.

Production of Rubber-Modified Thermoplastic Elastomer (A-2) A glass reactor was charged with 150 parts by weight of deionized water and 80 parts by weight (solid content) of styrene-butadiene rubber latex (a-2), followed by nitrogen substitution. After nitrogen substitution, when the temperature in the tank was reached and reached 60 ° C., 0.3 part by weight of lactose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 65 ° C., an emulsifier prepared by dissolving 1.0 part by weight of potassium oleate in a mixed solution of 5 parts by weight of acrylonitrile, 15 parts by weight of styrene, 0.15 part by weight of t-butyl hydroperoxide and 16 parts by weight of deionized water. The aqueous solution was continuously added dropwise over 3 hours. After dripping, it was kept for 3 hours to obtain a latex of a rubber-modified thermoplastic elastomer (A-2). Then, powder of rubber-modified thermoplastic elastomer (A-2) was obtained by salting out, dehydrating and drying. The graft ratio of the rubber-modified thermoplastic elastomer (A-2) was 19%, and the storage elastic modulus in the acetone insoluble part was 21 MPa.

Production of Rubber Modified Thermoplastic Elastomer (A-3) A glass reactor was charged with 150 parts by weight of deionized water and 75 parts by weight (solid content) of butyl acrylate rubber latex (a-1), followed by nitrogen substitution. After nitrogen replacement, when the temperature in the tank was increased to 55 ° C., 0.4 parts by weight of lactose, 0.3 parts by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 60 ° C., an emulsifier prepared by dissolving 1.0 part by weight of potassium oleate in a mixed liquid of 8 parts by weight of acrylonitrile, 17 parts by weight of styrene, 0.4 part by weight of t-butyl hydroperoxide and 16 parts by weight of deionized water. The aqueous solution was continuously added dropwise over 3 hours. After dripping, it was kept for 3 hours to obtain a latex of a rubber-modified thermoplastic elastomer (A-3). Then, powder of rubber-modified thermoplastic elastomer (A-3) was obtained by salting out, dehydrating and drying. The graft ratio of the rubber-modified thermoplastic elastomer (A-3) was 25%, and the storage elastic modulus in the acetone insoluble part was 8.2 MPa.

Production of Rubber Modified Thermoplastic Elastomer (A-4) A glass reactor was charged with 150 parts by weight of deionized water and 90 parts by weight (solid content) of styrene-butadiene rubber latex (a-2), followed by nitrogen substitution. After nitrogen substitution, when the temperature in the tank was reached and reached 60 ° C., 0.3 part by weight of lactose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 65 ° C, 1.0 part by weight of potassium oleate is dissolved in a mixture of 7 parts by weight of methyl methacrylate, 3 parts by weight of styrene, 0.15 part by weight of t-butyl hydroperoxide and 16 parts by weight of deionized water. The emulsifier aqueous solution was continuously added dropwise over 1 hour. After dripping, it was kept for 3 hours to obtain a latex of a rubber-modified thermoplastic elastomer (A-4). Then, powder of rubber-modified thermoplastic elastomer (A-4) was obtained by salting out, dehydrating and drying. The graft ratio of the rubber-modified thermoplastic elastomer (A-4) was 9%, and the storage elastic modulus in the acetone insoluble part was 3.7 MPa.

Production of Rubber-Modified Thermoplastic Elastomer (A-5) A glass reactor was charged with 200 parts by weight of deionized water and 97 parts by weight (solid content) of butyl acrylate rubber latex (a-1), followed by nitrogen substitution. After nitrogen substitution, when the temperature in the tank was increased to 55 ° C., 0.3 part by weight of lactose, 0.05 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 60 ° C., a mixed solution of 1 part by weight of acrylonitrile, 2 parts by weight of styrene and 0.05 part by weight of t-butyl hydroperoxide was continuously added dropwise over 30 minutes. After dripping, it was kept for 1 hour to obtain a latex of a rubber-modified thermoplastic elastomer (A-5). Then, powder of rubber-modified thermoplastic elastomer (A-5) was obtained by salting out, dehydrating and drying. The graft ratio of the rubber-modified thermoplastic elastomer (A-5) was 2%, and the storage elastic modulus in the acetone insoluble part was 0.2 MPa.

Production of Rubber Modified Thermoplastic Elastomer (A-6) In a glass reactor, 150 parts by weight of deionized water and 65 parts by weight (solid content) of styrene-butadiene rubber latex (a-2) were charged and nitrogen substitution was performed. After nitrogen substitution, when the temperature in the tank was reached and reached 60 ° C., 0.3 part by weight of lactose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 65 ° C., an emulsifier prepared by dissolving 1.0 part by weight of potassium oleate in a mixed solution of 9 parts by weight of acrylonitrile, 26 parts by weight of styrene, 0.15 part by weight of t-butyl hydroperoxide and 16 parts by weight of deionized water. The aqueous solution was continuously added dropwise over 3 hours. After dripping, it was kept for 3 hours to obtain a latex of a rubber-modified thermoplastic elastomer (A-6). Thereafter, salting out, dehydration and drying were performed to obtain a powder of rubber-modified thermoplastic elastomer (A-6). The graft ratio of the rubber-modified thermoplastic elastomer (A-6) was 45%, and the storage elastic modulus of the acetone insoluble part was 92 MPa.

Production of Rubber Modified Thermoplastic Elastomer (A-7) A glass reactor was charged with 200 parts by weight of deionized water and 93 parts by weight (solid content) of butyl acrylate rubber latex (a-1) to perform nitrogen substitution. After nitrogen substitution, when the temperature in the tank was increased to 55 ° C., 0.3 part by weight of lactose, 0.05 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 60 ° C., a mixed solution of 2 parts by weight of acrylonitrile, 5 parts by weight of styrene, and 0.05 parts by weight of t-butyl hydroperoxide was continuously added dropwise over 60 minutes. After dripping, it was kept for 1 hour to obtain a latex of a rubber-modified thermoplastic elastomer (A-7). Then, the powder of rubber-modified thermoplastic elastomer (A-7) was obtained by salting out, dehydrating and drying. The graft ratio of the rubber-modified thermoplastic elastomer (A-7) was 5%, and the storage elastic modulus in the acetone insoluble part was 0.3 MPa.

Production of Thermoplastic Resin (B) Latex 120 parts of deionized water and 0.3 part of potassium oleate were added to a glass reactor, followed by nitrogen substitution. Then, after adding 9 parts of styrene and 3 parts of acrylonitrile, the reactor was heated to 60 ° C., and an aqueous solution in which 0.4 part of potassium persulfate was dissolved in 10 parts of deionized water was added as a polymerization initiator. . Thereafter, an aqueous solution obtained by dissolving 66 parts of styrene, 22 parts of acrylonitrile and 1.2 parts of potassium oleate in 20 parts of deionized water was continuously added at 60 ° C. for 3 hours, followed by polymerization at 60 ° C. for 3 hours. A latex of the plastic resin (B) was obtained.

Production of rubber-modified thermoplastic elastomer composition (C-1) 85 parts by weight of latex of rubber-modified thermoplastic elastomer (A-1) (solid content conversion) and 15 parts by weight of latex of thermoplastic resin (B) (solid content) Conversion) was mixed and salted out, dehydrated and dried to obtain a powder of the rubber-modified thermoplastic elastomer composition (C-1).

Production of Thermoplastic Elastomer Composition (C-2) 80 parts by weight of latex of rubber-modified thermoplastic elastomer (A-5) (solid content conversion) and 20 parts by weight of latex of thermoplastic resin (B) (solid content conversion) Were mixed, salted out, dehydrated and dried to obtain a powder of the rubber-modified thermoplastic elastomer composition (C-2).

Production of Thermoplastic Elastomer Composition (C-3) 80 parts by weight of latex of rubber-modified thermoplastic elastomer (A-2) (in terms of solid content) and 20 parts by weight of latex of thermoplastic resin (B) (in terms of solid content) Were mixed, salted out, dehydrated and dried to obtain a powder of rubber-modified thermoplastic elastomer composition (C-3).

Evaluation of Softness A rubber-modified thermoplastic elastomer or a rubber-modified thermoplastic elastomer composition was melt-pressed to prepare a sheet having a thickness of 3 mm. The Shore A hardness of this sheet was measured using a Shore A hardness meter manufactured by Zwick. The smaller the Shore A hardness, the better the softness. The measurement results are shown in Table 1.

Evaluation of Tackiness A rubber-modified thermoplastic elastomer or a rubber-modified thermoplastic elastomer composition is melt-pressed to create a sheet having a thickness of 1 mm, cut into a strip having a length of 40 mm and a width of 5 mm, and a test piece is prepared. Created. The test pieces were placed side by side on a black mount. On top of that, the filter paper is stacked and pressure-bonded by passing through a roll whose temperature is adjusted to 30 ° C. After the filter paper is peeled off, the adhesion of the filter paper to the surface of each test piece is observed. Elastomer tackiness was evaluated. The evaluation was relatively visually evaluated as follows, with ◎ indicating that the tackiness with little fiber adhesion was small and excellent, and × indicating that the fiber adhesion was large and adhesion was greatly inferior. The evaluation results are shown in Table 1.
(Excellent) ◎>○>△> × (poor)

  As shown in Table 1, Examples 1 to 5 are examples of the rubber-modified thermoplastic elastomer and the elastomer composition according to the present invention, and were excellent in the balance between tackiness and softness.

  As shown in Table 1, Comparative Examples 1 and 2 were inferior in adhesiveness or softness because the rubber-like polymer content of rubber-modified thermoplastic elastomer, the graft ratio and the storage elastic modulus were outside the scope of the present invention. As a result. Since Comparative Example 3 had a storage elastic modulus of less than 0.5 MPa, it resulted in poor adhesion. Comparative Example 4 uses another thermoplastic resin, and even if the content of the rubber-like polymer of the rubber-modified thermoplastic elastomer composition is within the scope of the present invention, the graft ratio and the storage elastic modulus are out of the scope of the present invention. Therefore, the result was inferior in tackiness. Comparative Example 5 is an example in which the content of the rubber-like polymer is less than 70% by weight using other thermoplastic resins, even if the graft ratio and the storage elastic modulus are within the range of the present invention. The result was inferior.

  Since the rubber-modified thermoplastic elastomer and the elastomer composition of the present invention are excellent in adhesiveness and softness, they are highly useful in the fields of automobiles, home appliances, OA equipment, building materials, and the like.

Claims (1)

In the presence of 70 to 95 parts by weight of a rubbery polymer, 5-30 parts by weight of an aromatic vinyl monomer and another vinyl monomer copolymerizable with the aromatic vinyl monomer are graft-polymerized. The rubber-modified thermoplastic elastomer (A) and other thermoplastic resins (B ) characterized in that the graft ratio is 7 to 35% and the storage elastic modulus of acetone insolubles is 0.5 to 40 MPa. A rubber-modified thermoplastic elastomer composition comprising a rubber-modified thermoplastic elastomer composition containing 80 to 95% by weight of the rubber-like polymer component in the composition.