JP2018083885A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition that is soft and has excellent touch feeling, has excellent wear resistance and scratch resistance, and is difficult to cause blocking between pellets, compacts formed of the composition, and composite compacts formed by fusing the composition with the member.SOLUTION: A thermoplastic elastomer composition that includes a styrenic elastomer A having a content of styrenic monomer units of 45 to 80% by mass and a polyolefin resin B having a weight average molecular weight of 1,000,000 to 7,000,000 of 5 to 50 parts by mass relative to 100 parts by mass of the styrenic elastomer A and has the A hardness of 90 or lower, characterized in that the styrenic elastomer A is a styrenic copolymer having a hard segment that is a polymerization unit of the styrenic monomer and a soft segment that is a polymerization unit between the styrenic monomer and at least either one of olefin and conjugated diene, or hydrogenated product thereof, molded products made of the composition, and composite compacts obtained by fusing the composition with the member.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic elastomer composition useful for various molded articles used for automobiles, machines, construction materials, clothing, food containers, home appliances, electrical equipment, medical equipment, packaging materials, stationery and miscellaneous goods, and the like. The present invention relates to a molded article made of a product, and a composite molded body in which the composition is fused to a member.

  Styrenic elastomers are materials with excellent hygiene, wear resistance, and flexibility, and are used for grips, skin materials, tubes, cords, medical devices, and the like, but are not sufficiently scratch resistant. For this reason, in applications such as automotive interior parts and furniture skins, where flexibility and tactile sensation are required, the scratch resistance and wear resistance deteriorate due to the relationship between flexibility and trade-off. There is a need for excellent thermoplastic elastomer compositions.

  Patent Document 1 discloses that slidability is improved by using a thermoplastic elastomer such as a polystyrene-based thermoplastic elastomer together with an ultrahigh molecular weight polyethylene having a molecular weight of about 500,000 or more and a low molecular weight polyethylene having a molecular weight of 10,000 or less. Is disclosed.

  Patent Document 2 discloses that cross-copolymerization of an aromatic vinyl compound monomer with an ethylene-aromatic vinyl compound-aromatic polyene copolymer is excellent in scratch resistance and abrasion resistance.

  Patent Document 3 discloses a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate as slidability modifiers that can impart excellent slidability, surface appearance and impact resistance to thermoplastic elastomers. There is disclosed a slidability modifier obtained by mixing a silicone-based oil or an olefin-based oil (B) with a graft copolymer (A) obtained by graft-polymerizing a vinyl monomer to a composite rubber made of

JP-A-63-101441 JP 2009-102515 A JP 2001-261919 A

  However, Patent Document 1 also describes that low molecular weight polyethylene exhibits oil-like properties, and such a product is likely to cause blocking between pellets, so that it can be used industrially as a molding material. Is unsuitable.

  The cross-copolymer described in Patent Document 2 is also not necessarily sufficient in abrasion resistance with scratches, and the pellets are likely to block each other, which is unsuitable for industrial use as a molding material.

  In addition, since the slidability modifier described in Patent Document 3 requires an oil component, there is a problem of oil bleed, the pellets tend to block each other, and are difficult to use industrially as a molding material. The surface of the molded body is easy to stick and has a poor touch feeling.

  Therefore, there is a demand for a thermoplastic elastomer composition that is flexible and has excellent wear resistance and scratch resistance, but both pellets are prone to blocking and are not suitable for industrial use as molding materials. It is.

  An object of the present invention is to provide a thermoplastic elastomer composition that is flexible, has good tactile sensation, is excellent in wear resistance and scratch resistance, and is less likely to cause blocking between pellets, a molded article comprising the composition, and the composition as a member An object of the present invention is to provide a composite molded body fused to the above.

The present invention
[1] A styrene elastomer A having a styrene monomer unit content of 45 to 80% by mass and a polyolefin resin B having a weight average molecular weight of 1,000,000 to 7,000,000 are mixed with respect to 100 parts by mass of the styrene elastomer A. A thermoplastic elastomer composition containing ~ 50 parts by mass and having an A hardness of 90 or less, wherein the styrene elastomer A is a polymer segment of a styrene monomer, and a styrene monomer A thermoplastic elastomer composition, which is a styrene copolymer or a hydrogenated product thereof having a soft segment that is a copolymer unit of olefin and at least one of olefin and conjugated diene,
[2] A molded article comprising the thermoplastic elastomer composition according to [1], and [3] a composite molded article obtained by fusing the thermoplastic elastomer composition according to [1] and a nonpolar resin.

  The thermoplastic elastomer composition of the present invention is flexible and tactile, has excellent wear resistance and scratch resistance, and is less likely to cause blocking between pellets, and further has moldability and fusion to nonpolar resins. Therefore, it is easy to apply as various industrial products and parts.

  The thermoplastic elastomer composition of the present invention contains a styrene elastomer A and an ultrahigh molecular weight polyolefin resin B having a high content of styrene monomer units. Generally, the higher the content of the styrenic monomer unit, the less the stickiness and the better the tactile sensation. On the other hand, it becomes harder and the flexibility tends to decrease. However, in the present invention, the flexibility of the thermoplastic elastomer composition can be supplemented by using an ultrahigh molecular weight polyolefin resin in combination with a styrene elastomer having a high content of styrene monomer units. An excellent effect of improving friction and scratch resistance is achieved.

  The content of the styrene monomer unit in the styrene elastomer A is 45% by mass or more, preferably 50% by mass or more, more preferably 55% by mass or more, from the viewpoint of reducing stickiness. Therefore, it is 80% by mass or less, preferably 75% by mass or less, more preferably 70% by mass or less. In the present invention, the styrenic monomer includes not only styrene but also o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, etc. Also included are styrene derivatives substituted with ~ 4 alkyl groups.

  Examples of monomers other than styrene monomers include conjugated dienes, olefins, methacrylate monomers, acrylate monomers, unsaturated nitrile monomers, and vinyl chloride monomers. Can be mentioned.

  Examples of the conjugated diene include butadiene, isoprene, 1,3-pentadiene and the like.

  Examples of the olefin include ethylene, propylene, butylene and the like.

  The styrene elastomer A may be either a block copolymer or a random copolymer of a styrene monomer and another monomer, and has both a block copolymer unit and a random copolymer unit. You may do it. Moreover, these mixtures may be sufficient.

  In the present invention, the styrenic elastomer A includes a hard segment that is a polymerization unit of a styrenic monomer, a styrenic monomer, from the viewpoint of suppressing a decrease in flexibility accompanying an increase in the styrenic monomer unit. A styrene copolymer having a soft segment that is a copolymer unit with at least one of an olefin and a conjugated diene or a hydrogenated product thereof, and specific examples of such a styrene elastomer include the following three types: . These may be used alone or in combination of two or more.

Styrene elastomer A1:
A soft segment having a region containing a conjugated diene unit as a main constituent unit and a region containing a styrene monomer unit as a main constituent unit, which is a copolymerized unit of a styrene monomer and a conjugated diene, and Hydrogenated styrenic elastomer A2 of a triblock type controlled distribution block copolymer having hard segments that are polymerized units of styrenic monomers at both ends:
Hydrogenated styrenic elastomer of triblock random copolymer having hard segments that are polymerized units of styrene monomer at both ends of a soft segment that is a random copolymerized unit of styrene monomer and conjugated diene A3:
A cross copolymer having a soft segment, which is a random copolymer unit of a styrene monomer and an olefin, as a main chain and a hard segment as a polymer unit of a styrene monomer as a side chain

  The content of styrene monomer units in these styrene elastomers is the total amount of styrene monomer units in the hard segment and styrene monomer units in the soft segment.

In addition, as for the styrene-type elastomer A containing a conjugated diene unit, it is preferable that a part or all of the unsaturated bond of a conjugated diene unit is hydrogenated. By hydrogenating the unsaturated bond of the conjugated diene unit, the unsaturated bond is reduced and the heat resistance, weather resistance and mechanical properties are improved. The hydrogenation rate is preferably 80% or more, and more preferably 90% or more. In the present invention, the hydrogenation rate is determined by measuring the content of carbon-carbon double bonds derived from the conjugated diene in the styrene-based elastomer A by ¹ H-NMR spectrum before and after hydrogenation. Can be sought.

  The styrenic elastomer A1 is a copolymer of a conjugated diene and a styrene monomer, and includes a region containing a conjugated diene unit as a main constituent unit, preferably 50% by mass or more, and a styrene monomer unit as a soft segment. It has a block unit having a controlled distribution structure having a region containing preferably 50% by mass or more as a main constituent unit, and is called a “controlled distribution block copolymer”. The triblock controlled distribution block copolymer having hard segments that are polymerized units of styrene monomer at both ends of the soft segment is flexible and melts even if the content of the entire styrene monomer unit increases. It is preferable because the fluidity is hardly lowered.

  A block unit containing a conjugated diene unit and a styrenic monomer unit and having a controlled distribution structure contains at least two regions containing the conjugated diene unit as a main constituent unit and a styrene monomer unit as a main constituent unit. The terminal adjacent to the hard segment block unit is preferably a region containing a conjugated diene unit as a main constituent unit.

  A hydrogenated product of a triblock type controlled distribution styrene block copolymer in which the conjugated diene is butadiene is called a control distribution SEBS. As a commercial product of the control distribution SEBS, for example, A manufactured by Kraton Polymer Co., Ltd. Series etc. are mentioned.

  Control distribution block copolymers are well known in the technical field, and are described in, for example, JP-A-2007-84821 and JP-T-2013-518170.

  In the triblock random copolymer of the styrene elastomer A2, the content of the styrene monomer unit in the random copolymer unit is preferably 45 to 80% by mass, more preferably 50 to 75% by mass, and further preferably. Is 55 to 75% by mass.

  Moreover, content of the conjugated diene unit in a random copolymerization unit becomes like this. Preferably it is 20-55 mass%, More preferably, it is 25-50 mass%, More preferably, it is 30-45 mass%. The conjugated diene is preferably butadiene.

  Examples of commercially available triblock random copolymers include S.O.E. series manufactured by Asahi Kasei Corporation.

  In the main chain of the cross copolymer of the styrene elastomer A3, a styrene polyene monomer is used as a styrene monomer in order to form a side chain in addition to the styrene monomer exemplified above. Used.

  A styrene-based polyene monomer is a compound capable of coordination polymerization having a plurality of double bonds (vinyl groups) and a benzene ring, and one of the double bonds (vinyl groups) is used for coordination polymerization. The double bond left in the state is a compound capable of anion polymerization. Suitable aromatic polyene monomers include at least one selected from the group consisting of o-divinylbenzene, p-divinylbenzene and m-divinylbenzene.

  In the random copolymerization unit of the olefin that is the main chain of the cross-copolymer and the styrene monomer including the styrene polyene monomer, the content of the styrene monomer unit other than the styrene polyene monomer is From the viewpoints of flexibility, moldability, abrasion resistance, and scratch resistance, it is preferably 8 to 28 mol%, more preferably 10 to 25 mol%. The content of the styrenic polyene monomer unit is preferably 0.01 to 0.5 mol%, more preferably 0.01 to 0.2 mol%. The content of olefin units is preferably 17 to 60 mol%, more preferably 20 to 55 mol%. Ethylene is preferred as the olefin.

  The styrene monomer used for the hard segment as the side chain is a styrene monomer other than the styrene polyene monomer, and even if it is the same compound as the styrene monomer used for the main chain, Different compounds may be used.

  The mass ratio (main chain / side chain) of the main chain (soft segment) and side chain (hard segment) in the cross-copolymer is preferably 60/40 to 95/5 from the viewpoint of flexibility and heat resistance. Preferably it is 70 / 30-95 / 5.

  The cross copolymer is, for example, a random copolymer obtained by copolymerizing a styrene monomer containing ethylene and a styrene polyene monomer by coordination polymerization using a single site coordination polymerization catalyst. It is obtained by anionic polymerization using an anionic polymerization initiator in the presence of a styrene monomer and forming a side chain composed of a polystyrene chain with a random copolymer as a main chain. For a specific manufacturing method, Patent Document 2 can be referred to.

  Examples of commercially available cross-copolymers include SE polymers manufactured by Denki Kagaku Kogyo Co., Ltd.

  The melting point of the cross copolymer is preferably 100 ° C. or higher, more preferably 110 ° C. or higher from the viewpoint of heat resistance, and preferably 250 ° C. or lower, more preferably 200 ° C. or lower, from the viewpoint of moldability.

  As the styrene elastomer A, from the viewpoint of oil resistance, styrene elastomer A2 and / or A3 are preferable, and styrene elastomer A3 is more preferable.

  The styrenic elastomer A preferably contains a crystalline component. The styrene-based elastomer containing a crystalline component includes a portion that undergoes crystal shrinkage and a portion that does not crystallize because the crystalline component shrinks due to crystallization upon cooling after the raw material component is melt-kneaded in the manufacturing process of the thermoplastic elastomer composition. Slight irregularities are formed on the surface due to the difference of Thereby, the tactile sensation of the thermoplastic elastomer composition is further improved. Among the styrene elastomers A, the styrene elastomer A3 (cross copolymer) includes a crystalline component, and the ethylene unit in the main chain is the crystalline component. The presence of the crystalline component can be confirmed by the presence or absence of a crystal melting peak in DSC analysis. The heat of crystal fusion of the cross copolymer is preferably 0.05 to 0.50 J / g, more preferably 0.10 to 0.30 J / g.

  The weight average molecular weight of the styrenic elastomer A is preferably 30,000 or more, more preferably 40,000 or more from the viewpoint of improving wear resistance, and preferably 500,000 or less, more preferably 350,000 or less from the viewpoint of moldability. . When the styrene-based elastomer A is composed of a plurality of styrene-based elastomers, it is preferable that the weighted average value of the weight average molecular weight of each elastomer falls within the above range.

  The content of the styrenic elastomer A in the thermoplastic elastomer composition is preferably 50 to 95% by mass, more preferably 60 to 90% by mass.

  The polyolefin resin B has an ultra high molecular weight. By using the ultrahigh molecular weight polyolefin resin B together with the styrene elastomer A, the wear resistance is improved without causing a decrease in flexibility due to the compatibility of the polyester resin B and the styrene elastomer A. From these viewpoints, the weight average molecular weight of the polyolefin resin B is 1,000,000 or more, preferably 1,300,000 or more, more preferably 1,600,000 or more, and 7,000,000 or less.

  The polyolefin resin B preferably has a melt mass flow rate (MFR) as low as possible from the viewpoint of preventing a decrease in flexibility due to compatibility with the styrene-based elastomer A during the production of the composition. The MFR of the polyolefin resin B at 190 ° C. and a nominal load of 2.16 kg is preferably 0.1 g / 10 min or less, more preferably 0.05 g / 10 min or less.

  Examples of the polyolefin resin B include polyethylene, polypropylene, ethylene-propylene copolymer, and the like. Among these, polyethylene is preferable from the viewpoint of wear resistance and self-lubricity.

  The polyolefin resin B is preferably in the form of powder from the viewpoint of dispersion without being compatible with the styrene-based elastomer A. The volume-based average particle diameter of the powder is preferably 10 to 200 μm.

  The content of the polyolefin resin B is 5 parts by mass or more, preferably 7 parts by mass or more, more preferably 10 parts by mass or more from the viewpoint of wear resistance with respect to 100 parts by mass of the styrene elastomer A. From this viewpoint, it is 50 parts by mass or less, preferably 45 parts by mass or less, more preferably 40 parts by mass or less.

  The content of the polyolefin resin B in the composition of the present invention is preferably 3 to 35% by mass, more preferably 6 to 30% by mass.

  The composition of the present invention preferably further contains a lubricant C from the viewpoint of further improving the wear resistance.

  The lubricant C is composed of a polymer component that increases the compatibility between the styrenic elastomer A and at least one slippery component selected from the group consisting of silicone, fluorine, and amide from the viewpoint that oil bleeding is difficult to occur. Solid lubricants are preferred. Among these solid lubricants, silicone-based polymer lubricants such as silicone-modified (meth) acrylic polymers and silica-supported ultrahigh molecular weight silicone pellets (silicon concentrate) are preferable, and silicone-modified (meth) acrylic polymers are more preferable.

  The silicone-modified (meth) acrylic polymer has a structure containing at least one polysiloxane portion and at least one (meth) acrylic acid polymer portion. For example, (Acrylates / acrylic acid manufactured by Shin-Etsu Chemical Co., Ltd.) Ethylhexyl / dimethicyl methacrylate copolymer (trade name: KP578), wax type (acrylates / stearyl acrylate / dimethicone methacrylate) copolymer (trade name: KP561P), (acrylates / behenyl acrylate / dimethicone methacrylate) copolymer (KP562P) ), Saimak of Toagosei Co., Ltd., Charine of Nissin Chemical Industry Co., Ltd., and others having various structures and characteristics are known.

  The higher the melting point of the silicone-modified (meth) acrylic polymer, the higher the wear resistance, and it is preferably 50 ° C. or higher, more preferably 100 ° C. or higher. Further, when the composition is melt-kneaded, it is preferable that the silicone-modified (meth) acrylic polymer is also melted and mixed more uniformly with the components of the composition, and is preferably 220 ° C. or less, more preferably 200 ° C. or less. . From these viewpoints, the melting point of the silicone-modified (meth) acrylic polymer is preferably 50 to 220 ° C, more preferably 100 to 200 ° C.

  Other lubricants C include paraffin and hydrocarbon resin lubricants (paraffin wax, liquid paraffin, polyethylene wax, etc.), fatty acid lubricants (stearic acid, hydroxystearic acid, composite stearic acid lubricant, hardened oil, etc.), fatty acids Amide lubricants (stearoamide, oxy-stearamide, oleyl amide, erucyl amide, ricinol amide, behen amide, methylol amide, monoamide type of higher fatty acids, methylene bis stearamide, methylene bis stearo behenamide, ethylene bis stearamide Higher fatty acid bisamide type lubricants, stearamide type lubricants, complex type amide type lubricants, etc.), fatty acid ester type lubricants (methyl hydroxy stearate, polyhydric alcohol fatty acid ester, saturated fatty acid ester, Tellurium wax, complex ester lubricant, etc.), fatty acid ketone lubricant, aliphatic alcohol (higher alcohol, higher alcohol complex type, higher alcohol / ester, etc.), partial ester of fatty acid and polyhydric alcohol (glycerin fatty acid ester, hydroxy) Stearic acid triglyceride, sorbitan fatty acid ester, etc.), composite lubricants, distearyl / epoxy / hexahydrophthalate, phthalic anhydride derivatives, etc., and these may be used alone or in combination of two or more. Also good.

  The content of the lubricant C is preferably 1 to 20 parts by mass, more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the styrene elastomer A.

  Further, the content of the lubricant C in the composition of the present invention is preferably 0.5 to 16% by mass, more preferably 1 to 10% by mass.

  The composition of the present invention may contain other thermoplastic resins and thermoplastic elastomers as long as the effects of the present invention are not impaired. Among these, the polar elastomer can improve the fusion property of the composition to the polar resin. The polar elastomer is not particularly limited, and examples thereof include NBR (nitrile rubber), polyurethane rubber, epichlorohydrin rubber, polyester thermoplastic elastomer, polyurethane thermoplastic elastomer, polyamide thermoplastic elastomer, and the like.

  The thermoplastic elastomer composition of the present invention is, as necessary, a reinforcing agent such as carbon black, silica, carbon fiber, and glass fiber, an inorganic filler, and an insulating heat conductive filler as long as the effects of the present invention are not impaired. , Pigments, hydrated metal compounds, red phosphorus, ammonium polyphosphate, antimony, silicone and other flame retardants, antistatic agents, tackifiers, crosslinking agents, crosslinking aids, heat stabilizers, antioxidants, light stabilizers, You may contain various additives, such as a ultraviolet absorber, an antiblocking agent, a sealing property improving agent, a mold release agent, a coloring agent, and a fragrance | flavor.

  The thermoplastic elastomer composition of the present invention can be obtained, for example, by melt-kneading a styrene-based elastomer A and a polyolefin resin B and, if necessary, a raw material containing a lubricant C and other additives, and solidifying by cooling.

  In the melt-kneading, from the viewpoint of further improving the scratch resistance, it is preferable to knead the raw material components so that the polyolefin resin B is not compatible with the styrenic elastomer A due to melting. From this viewpoint, the temperature for melt kneading is preferably 100 to 230 ° C, more preferably 140 to 200 ° C.

  In the case of melt mixing, a kneader or a general melt extruder can be used, and it is preferable to use a single screw extruder for improving the kneading state. As for the supply to the extruder, various components may be directly supplied to the extruder, a mixture of various components using a mixing device such as a Henschel mixer in advance may be provided from one hopper, or two hoppers. Each of the components may be charged and used while being quantified with a screw or the like under the hopper.

  The thermoplastic elastomer composition can be used by directly forming a molded product obtained by melting and mixing into pellets, powders before forming a molded product to be used as a final product depending on the application. Intermediate products such as sheets can be used. For example, it is melt-mixed by an extruder, extruded into a strand, and cut into pellets such as a cylindrical shape and a rice grain by a cutter while cooling in cold water. The obtained pellets can be usually formed into a predetermined sheet-like molded product or a molded product by a molding method such as injection molding, extrusion molding, or press molding.

  The A hardness of the thermoplastic elastomer composition of the present invention is 90 or less, preferably 85 or less, more preferably 80 or less, preferably 20 or more, more preferably 25 or more, and still more preferably, from the viewpoint of flexibility. Is over 30.

  A molded body is obtained by appropriately heat-molding the thermoplastic elastomer composition of the present invention according to a conventional method. The use of the molded product obtained by thermoforming the thermoplastic elastomer composition of the present invention is not particularly limited, and general styrene elastomers, polyolefin elastomers, polyurethane elastomers, polyamide elastomers, acrylic elastomers And polyester elastomers can be used.

  The apparatus used for manufacturing a molded body using the thermoplastic elastomer composition of the present invention can be any molding machine capable of melting a molding material. Examples thereof include a kneader, an extrusion molding machine, an injection molding machine, a press molding machine, a blow molding machine, and a mixing roll.

  The thermoplastic elastomer composition of the present invention can also be used as a composite molding material. In addition to being well fused with a nonpolar resin, when a polar elastomer or the like is used in combination, the polarity of metals, ceramics, glass, polar resins, etc. Good adhesion to a member with

  Accordingly, the present invention further provides a composite molded body in which the thermoplastic elastomer composition of the present invention and a member, preferably a nonpolar resin, are fused and integrated. Accordingly, it is possible to combine a member having a complicated joint surface and a member having joint surfaces having different shapes.

  Examples of the nonpolar resin include polyethylene, polypropylene, and ethylene-propylene copolymer. Among these, polyethylene is preferable from the viewpoints of high cold resistance and impact resistance, and excellent fusion properties with the thermoplastic elastomer composition of the present invention. The copolymer may be any of a random copolymer, a block copolymer, and a graft copolymer.

  In the present invention, the fusion is carried out by applying heat equal to or higher than the melting point of the thermoplastic elastomer composition of the present invention to form a melt, and then solidifying at a temperature equal to or lower than the melting point, thereby fixing to the interface to be fused. A phenomenon. To apply heat, a hot press machine, a heated roll machine, a hot air generator, heated steam, an ultrasonic welder, a high frequency welder, a laser, or the like can be used. Therefore, even if the interface of the fused part is a complicated three-dimensional shape, it can be well blended and integrated into the complicated three-dimensional shape. The fusion between the thermoplastic elastomer composition and the member may be entirely or partially.

  The composite molded product obtained by fusing the thermoplastic elastomer composition of the present invention to a member is injection molding, injection compression molding, insert molding, multicolor molding, vacuum molding, pressure molding, blow molding, hot press molding, foam molding, laser. The thermoplastic elastomer composition of the present invention is not self-adhesive like an adhesive and is easy to handle, although it can be obtained by molding by a method such as fusion molding or extrusion molding. Therefore, it can be applied to injection molding.

  The composite molded body in which the thermoplastic elastomer composition of the present invention is fused to a member includes an insert molded body in which a nonpolar resin is inserted into a molded body composed of a thermoplastic elastomer composition, a thermoplastic elastomer composition, and a nonpolar body. Examples include composite molded bodies obtained by multicolor molding of resins.

  The molded product of the thermoplastic elastomer composition of the present invention is used as various molded products used in automobiles, machines, construction materials, clothing, food containers, home appliances, electrical equipment, medical equipment, packaging materials, stationery / miscellaneous goods, etc. However, it can be suitably used as a sheet material or a skin material for furniture, automobile interior materials, etc., taking advantage of the features that it is flexible and has a good tactile feel, and also has good wear resistance and scratch resistance. .

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Various physical properties such as raw materials used in Examples and Comparative Examples were measured by the following methods.

<Styrene elastomer>
[Content of styrene monomer unit]
Proton NMR measurement is performed with a nuclear magnetic resonance apparatus (manufactured by BRUKER, Germany, DPX-400), and the content of styrene and / or styrene derivatives is determined by quantifying the characteristic groups of styrene.

[Weight average molecular weight (Mw)]
Under the following measurement conditions, the molecular weight is measured in terms of polystyrene by gel permeation chromatography, and the weight average molecular weight is determined.

Measuring device / pump: JASCO (manufactured by JASCO Corporation), PU-980
・ Column oven: Showa Denko KK, AO-50
・ Detector: Hitachi, RI (differential refractometer) detector L-3300
・ Column type: Showa Denko Co., Ltd. “K-805L (8.0 × 300mm)” and “K-804L (8.0 × 300mm)” each used in series ・ Column temperature: 40 ℃
・ Guard column: KG (4.6 × 10mm)
・ Eluent: Chloroform ・ Eluent flow rate: 1.0 ml / min
・ Sample concentration: about 1mg / ml
・ Sample solution filtration: 0.45μm pore size disposable filter made of polytetrafluoroethylene ・ Standard sample for calibration curve: Polystyrene made by Showa Denko K.K.

[Crystal melting heat]
Using a differential scanning calorimeter “DSC8500” (manufactured by PerkinElmer Japan Co., Ltd.), the sample was kept at 230 ° C. for 10 minutes and then cooled to 50 ° C. at a rate of 10 ° C./min. Heat to 230 ° C at a rate of 10 ° C per minute. The area of the melting peak obtained from the obtained DSC curve is defined as the heat of crystal melting.

[Melting point]
Using a differential scanning calorimeter “DSC8500” (manufactured by PerkinElmer Japan Co., Ltd.), the sample was kept at 230 ° C. for 10 minutes and then cooled to 50 ° C. at a rate of 10 ° C./min. Heat to 230 ° C at a rate of 10 ° C per minute. From the obtained DSC curve, the peak of the melting peak is defined as the melting point.

<Polyolefin resin>
[Weight average molecular weight (Mw)]
Under the following measurement conditions, the molecular weight is measured in terms of polystyrene by gel permeation chromatography, and the weight average molecular weight is determined.
-Pump: JASCO (JASCO Corporation), PU-980
・ Column oven: Showa Denko KK, AO-50
・ Detector: Hitachi, RI (differential refractometer) detector L-3300
・ Column type: Two TSKgel GNH6-HT (7.5 × 300mm) are used in series ・ Column temperature: 140 ℃
・ Guard column: KG (4.6 × 10mm)
-Eluent: o-dichlorobenzene (Wako Pure Chemical Industries) and BHT (Takeda Pharmaceutical) 0.025 mass% as an antioxidant
・ Eluent flow rate: 1.0ml / min
・ Sample concentration: about 1mg / ml
Standard sample for calibration curve: Polystyrene manufactured by Showa Denko K.K.

[Melt Mass Flow Rate (MFR)]
Measured under conditions of 190 ° C and nominal load of 2.16 kg in accordance with ASTM D1238.

[Average particle size]
The polyolefin particles dispersed in decane are measured with a Coulter Counter Multisizer (II) manufactured by Beckman Coulter, and the volume-based average particle diameter is measured.

<Lubricant>
[Average particle size]
Measurement is performed using a scanning electron microscope (SEM) apparatus.
The shape of the primary particles can be directly observed by scanning electron microscope observation. Select 30 arbitrary particles, measure the major axis and minor axis, normalize to ellipse, and calculate the cross-sectional area to calculate the area standard The average particle diameter can be calculated.

Measuring device / SEM: VE-8800 (manufactured by KEYENCE)
・ Acceleration voltage: 1.3kV

[Melting point]
Using a differential scanning calorimetry (DSC) apparatus, the melting peak temperature obtained by raising the temperature at 10 ° C./min according to the method specified in JIS K 7121 is defined as the melting point. When a plurality of melting peaks appear, the melting peak appearing at a lower temperature is taken as the melting point.

Examples 1-9 and Comparative Examples 1-10
(1) Production of thermoplastic elastomer composition The materials shown in Tables 4 and 5 were dry blended, the mixture was melt-mixed with an extruder under the following conditions, extruded into strands, cooled with cold water by a cutter, The pellets were cut to a diameter of about 3 mm and a thickness of about 3 mm to produce thermoplastic elastomer composition pellets.

[Melting and mixing conditions]
Extruder: Made by Technobel, KZW32TW-60MG-NH
Screw rotation speed: 200 ~ 650r / min
Cylinder temperature: 160 ℃ ~ 200 ℃

  The details of the raw materials described in Tables 4 and 5 used in Examples and Comparative Examples are as follows.

(2) Production of molded body of thermoplastic elastomer composition Pellets were injection molded under the following conditions to produce plate A having a thickness of 2 mm x width 125 mm x length 125 mm.

<Injection molding conditions>
Injection molding machine: 100MSIII-10E, manufactured by Mitsubishi Heavy Industries, Ltd.
Injection molding temperature: 200 ℃
Injection pressure: 98MPa, injection speed: 50%, holding pressure: 20%, holding time: 10sec
Injection time: 2sec
Mold temperature: 40 ℃

  Using the plate A, the following measurements or evaluations were performed on the compositions obtained in Examples 1 to 9 and Comparative Examples 1 to 10. The results are shown in Tables 4 and 5.

[Flexibility]
Plate A was used for 24 hours at an ambient temperature of 23 ° C. Measurement time: 1 second after the needle contacted the sample, load: 5 kg, all other conditions were as specified in JIS K 6253 The durometer A hardness was measured according to the standard.

[Abrasion resistance (Taber abrasion test)]
In accordance with JIS K 7204, the wear loss amount (mg) of plate A was measured at 23 ° C., wear wheel: H-22, rotation speed: 72 r / min, number of rotations: 1,000 times, load: 1000 g. The amount of wear loss is preferably 200 mg or less, more preferably 100 mg or less.

[Scratch resistance]
Uses a pencil hardness tester from Yasuda Seiki Seisakusho in accordance with JIS K5600-5-4 (General coating test methods-Part 5: Mechanical properties of coating films-Section 4: Scratch hardness (pencil method)) A scratch test was conducted.
Test piece: Plate A
Load: 100g
Pencil: H
A distance scratch test of at least 7 mm was performed at a speed of 0.5 to 1 mm / s, a 5 mm range was magnified from the test start point, and the state of the scratch was visually observed based on the following evaluation criteria.
〔Evaluation criteria〕
○: Scratches are not confirmed.
Δ: Scratches are confirmed only at the beginning of the test (within 3 mm at the beginning of scratching).
X: Scratches are confirmed on the entire test surface.

[Pellet block resistance]
Gently put 1kg of pellets before injection molding on plate A into a stainless steel container 150mm x 150mm x 200mm in height and let stand at 23 ° C and 50% RH for 24 hours. Discharged. The state of the pellets after discharge was visually observed and evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
○: Pellets are divided individually.
Δ: The pellet is partially agglomerated.
X: The pellets are generally in one lump.

[Feel]
Using a friction tester KSE-SE manufactured by Kato Tech Co., Ltd., a 10 mm x 10 mm piano wire sensor imitating a fingertip was brought into contact with the surface of plate A with a load of 25 g and slid 20 mm at a constant speed of 1 mm / sec. The tactile sensation was quantified as MIU and MMD from the frictional force and its fluctuation. MIU is a coefficient of friction, and a larger value means less slipping. MIU is preferably 1.5 or less. Further, MMD is a fluctuation value of the friction coefficient. The larger the value, the lower the smoothness and the greater the roughness. MMD is preferably 0.1 or less. Both MIU and MMD are in the preferred range at the same time, and those having an A hardness of 90 or less are particularly preferred because they cause a soft and smooth feel.

〔Oil resistance〕
In accordance with JIS K6258, the plate A was immersed in IRM903 oil manufactured by Nippon Sun Oil Co., Ltd., and the mass before and after immersion was measured. The mass fraction (%) increased by the immersion was calculated as the swelling ratio with the mass of the test piece before immersion as 100%. When there is no swelling of the plate A due to the test oil, it becomes 0%, but the larger the swelling, the larger the number, so the swelling rate is 0% or more, and the smaller the value, the better the oil resistance. . The swelling rate is preferably 100% or less, more preferably 50% or less.

From the above results, it can be seen that the thermoplastic elastomer compositions of Examples 1 to 9 are flexible and tactile, have excellent wear resistance, scratch resistance, and pellet block resistance, and also have good oil resistance. I understand.
In contrast, Comparative Example 1 in which the styrene elastomer does not have a copolymer part of a styrene monomer and an olefin and / or conjugated diene and the content of the styrene monomer unit is small is It lacks oil resistance.
Even in the case of the controlled distribution SEBS, Comparative Example 2 having a small content of styrene monomer units lacks the wear resistance, tactile sensation, and oil resistance.
Even if the content of the styrene monomer unit is large, Comparative Example 3 in which the styrene elastomer does not have a copolymer part of the styrene monomer and the olefin and / or conjugated diene is wear resistance and scratch resistance. Lack of stickiness and poor flexibility.
Comparative Examples 4 to 7 containing no polyolefin resin lack pellet resistance.
Even though the polyolefin resin is contained, Comparative Examples 8 and 9 having a small weight average molecular weight lack the scratch resistance.
Comparative Example 10 having too much polyolefin resin lacks flexibility.

(3) Production of composite molded body The plates A of Examples 1, 3, 4, and 6 were cut into a size of 25 mm in width and 120 mm in length.
2mm thick, 25mm wide, 120mm long plate A and the following non-polar resin of the same size as the plate A are stacked and hot press molded (temperature 200 ° C, preheating 2 minutes, pressure 3 minutes, cooling 2 Min, press pressure 10 MPa). All the plates were fused with each nonpolar resin to produce a composite sheet having a thickness of 4 mm.

[Nonpolar resin]
Low density polyethylene (LDPE): Novatec J802 (Nippon Polypro Co., Ltd.)
High density polyethylene (HDPE): Nipolon Hard 1200 (manufactured by Tosoh Corporation)
Block polypropylene (Block PP): PM870A (manufactured by Sun Allomer Co., Ltd.)

  The peel strength of the composite sheet was measured at an ambient temperature of 23 ° C. by a method based on JIS K6854-2 “Test method for adhesive peel strength (180 degree peel)”. Using the thermoplastic elastomer layer as the flexible adherent and the nonpolar resin layer as the rigid adherend, the thermoplastic elastomer layer is subjected to a tensile test in the 180 ° direction at 50 mm / min, and the thermoplastic elastomer layer and the nonpolar resin layer are The peel strength (unit: N / 25 mm) was measured. The results are shown in Table 6.

  From the above results, it can be seen that a composite molded body with a nonpolar resin can be obtained using the thermoplastic elastomer composition of the present invention.

  The thermoplastic elastomer composition of the present invention is used for various molded articles used in automobiles, machines, construction materials, clothing, electronic materials, food containers, home appliances, electrical equipment, medical equipment, packaging materials, stationery and miscellaneous goods, etc. It is done.

Claims (7)

  5 to 50 masses of styrene elastomer A having a styrene monomer unit content of 45 to 80 mass% and polyolefin resin B having a weight average molecular weight of 1,000,000 to 7,000,000 with respect to 100 mass parts of the styrene elastomer A. A thermoplastic elastomer composition having a hardness of 90 or less, wherein the styrene elastomer A is a hard segment that is a polymerized unit of a styrene monomer, a styrene monomer, an olefin, and A thermoplastic elastomer composition, which is a styrenic copolymer or a hydrogenated product thereof having a soft segment that is a copolymerized unit with at least one of conjugated dienes. A styrenic copolymer or a hydrogenated product thereof,
(i) A soft segment which is a copolymer unit of a styrene monomer and a conjugated diene, and has a region containing the conjugated diene unit as a main constituent unit and a region containing a styrene monomer unit as a main constituent unit And a hydrogenated triblock controlled distribution block copolymer having hard segments that are polymerized units of a styrene monomer at both ends thereof,
(ii) Hydrogenated product of a triblock random copolymer having a hard segment that is a polymer unit of a styrene monomer at both ends of a soft segment that is a random copolymer unit of a styrene monomer and a conjugated diene ,as well as
(iii) A group consisting of a cross copolymer having a soft segment as a random copolymer unit of a styrene monomer and an olefin as a main chain and a hard segment as a polymer unit of a styrene monomer as a side chain. The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition is at least one selected from the group.   The thermoplastic elastomer composition according to claim 1 or 2, wherein a melt mass flow rate of the polyolefin resin B at 190 ° C and a nominal load of 2.16 kg is 0.1 g / 10 min or less.   The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the styrene elastomer A contains a crystalline component.   Furthermore, the thermoplastic elastomer composition in any one of Claims 1-4 containing the lubricant C.   The molded object which consists of a thermoplastic-elastomer composition in any one of Claims 1-5.   A composite molded article obtained by fusing the thermoplastic elastomer composition according to any one of claims 1 to 5 and a nonpolar resin.