Thermoplastic elastomer composition

Abstract

To provide a thermoplastic elastomer composition that, thanks to its flexibility, offers adequate grip strength (anti-slip), ensures long-term retention of the grip strength through its resistance to wear, and further demonstrates superior heat weldability with polar resins.SOLUTION: A thermoplastic elastomer composition comprises a thermoplastic styrenic elastomer A, a thermoplastic urethane elastomer B1, a thermoplastic urethane elastomer B2, and a softener C. The thermoplastic urethane elastomer B1 comprises polyether polyol and isocyanate compound as constitutional units. The thermoplastic urethane elastomer B2 comprises polyester polyol and isocyanate compound as constitutional units.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic elastomer composition used as a grip material for hand tools such as screwdrivers and hammers, and power tools such as electric drills, electric saws, and nail guns. [Background technology]

[0002] The handles of hand tools and power tools are typically coated with a flexible elastomer material over a rigid core made of ABS resin or fiber-reinforced nylon resin, for improved usability and slip resistance. While styrene-based elastomers are commonly used as flexible materials with excellent grip, they have limitations in adhesion to polar resins such as ABS resin and nylon. Therefore, to improve adhesive performance, elastomer compositions have been proposed in which ester-based urethane elastomers are blended with styrene-based elastomers (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2020-524729 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, ester-based urethane elastomers and styrene-based elastomers have low compatibility and insufficient abrasion resistance. As wear progresses, the uneven surface pattern of the grip disappears, leading to a decrease in the anti-slip effect.

[0005] The object of the present invention is to provide a thermoplastic elastomer composition that exhibits sufficient grip (anti-slip) flexibility, wear resistance that maintains grip over a long period of time, and excellent heat-sealability to polar resins. [Means for solving the problem]

[0006] The present invention [1] A thermoplastic elastomer composition comprising thermoplastic styrene elastomer A, thermoplastic urethane elastomer B1, thermoplastic urethane elastomer B2, and softener C, wherein the thermoplastic urethane elastomer B1 contains a polyether polyol and an isocyanate compound as constituent units, and the thermoplastic urethane elastomer B2 contains a polyester polyol and an isocyanate compound as constituent units, [2] The thermoplastic elastomer composition according to [1], wherein the mass ratio of thermoplastic urethane elastomer B1 to thermoplastic urethane elastomer B2 is 1 / 99 to 99 / 1. [3] Furthermore, the thermoplastic elastomer composition according to [1] or [2], which contains a carboxyl group or acid anhydride group-containing styrene elastomer D, and [4] A thermoplastic elastomer composition according to any one of [1] to [3] above, wherein the A hardness of thermoplastic urethane elastomer B1 is 40 to 90 points, and the A hardness of thermoplastic urethane elastomer B2 is less than or equal to the A hardness of thermoplastic urethane elastomer B1. Regarding. [Effects of the Invention]

[0007] The thermoplastic elastomer composition of the present invention exhibits excellent effects in terms of flexibility that provides sufficient grip (anti-slip), abrasion resistance that maintains grip over a long period of time, and heat fusion properties to polar resins. [Modes for carrying out the invention]

[0008] The thermoplastic elastomer composition of the present invention contains a thermoplastic styrene elastomer A, a thermoplastic urethane elastomer, and a softening agent C, and is characterized by the use of a combination of a polyether-based thermoplastic urethane elastomer B1 and a polyester-based thermoplastic urethane elastomer B2 as the thermoplastic urethane elastomer.

[0009] Thermoplastic urethane elastomers are obtained by the reaction of polyols with isocyanate compounds. Among the various polyols used in thermoplastic urethane elastomers, polyester polyols are the most polar, exhibiting high adhesion to polar resins. However, they have poor compatibility with low-polarity styrene elastomers, forming a phase-separated structure. Therefore, mixed compositions of polyester-based thermoplastic urethane elastomers and thermoplastic styrene elastomers have low interfacial strength between the two elastomers, making them prone to tearing and resulting in poor abrasion resistance. On the other hand, polyether polyols have lower polarity than polyester polyols and exhibit stronger interfacial strength with styrene-based elastomers. In this invention, the detailed mechanism by which the combined use of these two types of thermoplastic polyurethane elastomers improves abrasion resistance is not clear, but it is presumed that the difference in polarity of the two elastomers affects the interfacial strength with the thermoplastic styrene elastomer and the dispersibility during mixing.

[0010] As thermoplastic styrene-based elastomer A, block copolymers comprising a styrene block of a polymer made of styrene monomers and a conjugated diene block of a polymer made of conjugated dienes, and hydrogenated versions thereof are preferred.

[0011] Examples of styrene monomers that make up styrene blocks include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, and α-methylstyrene.

[0012] Examples of conjugated dienes that make up a conjugated diene block include butadiene, isoprene, and 1,3-pentadiene.

[0013] The block copolymer consists of a hard segment made up of styrene block units and a soft segment made up of conjugated diene block units. From the viewpoint of determining the overall physical properties, the content of styrene monomer units in the block copolymer is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 20 to 50% by mass.

[0014] The hydrogenation of the block copolymer may be partial or complete, but hydrogenation reduces the unsaturated bonds, resulting in improved heat resistance, weather resistance, and mechanical strength. From these viewpoints, a hydrogenation rate of 80% or more is preferred, and 90% or more is more preferred. The hydrogenation rate is determined by the content of carbon-carbon double bonds derived from the conjugated diene compound in the block copolymer before and after hydrogenation. 1 It can be determined by measuring the 1H-NMR spectrum and then obtaining the result from the measured value.

[0015] Specific examples of hydrogenated block copolymers include styrene-ethylene-butylene-styrene block copolymers, styrene-ethylene-propylene-styrene block copolymers, styrene-ethylene-ethylene-propylene-styrene block copolymers, styrene-isobutylene-styrene block copolymers, styrene-butadiene rubber, acrylonitrile-butadiene rubber, pyridine-butadiene rubber, styrene-isoprene rubber, styrene-ethylene copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, poly(α-methylstyrene)-polybutadiene-poly(α-methylstyrene), poly(α-methylstyrene)-polyisoprene-poly(α-methylstyrene), ethylene-propylene copolymers, and styrene-chloroprene rubber. These may be used alone or as a mixture of two or more types, but from the viewpoint of raw material preparation and workability, at least one selected from the group consisting of styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and styrene-isobutylene-styrene block copolymer (SIBS) is preferable.

[0016] The A hardness of the thermoplastic styrene-based elastomer A is preferably 50 to 95 points, more preferably 60 to 85 points, and still more preferably 70 to 80 points.

[0017] The content of the thermoplastic styrene-based elastomer A in the thermoplastic elastomer composition is preferably 5 to 50% by mass, more preferably 8 to 35% by mass, and still more preferably 10 to 20% by mass.

[0018] The thermoplastic urethane-based elastomer B1 contains a polyether polyol and an isocyanate compound as constituent units, and is obtained by reacting a polyether polyol, an isocyanate compound, and optionally a chain extender by a conventional method. In the thermoplastic urethane-based elastomer B1, the site formed by polymerization of the isocyanate compound and the chain extender is a hard segment, and the site constituted by the polyether polyol is a soft segment.

[0019] Examples of the polyether polyol include polyether diols such as aliphatic polyether diols and aromatic polyether diols.

[0020] Examples of the aliphatic polyether diol include polyoxyalkylene (having 2 to 4 carbon atoms) glycols such as polyoxyethylene glycol, polyoxytrimethylene glycol, polyoxypropylene glycol, and polyoxytetramethylene glycol, and block copolymers of the aforementioned polyoxyalkylene glycols such as polyoxyethylene-polyoxypropylene block copolymers.

[0021] Examples of the aromatic polyether diol include diols obtained by adding an alkylene (having 2 to 4 carbon atoms) oxide to an aromatic diol, such as ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A.

[0022] The polyether polyol may be used as a single compound or in combination of two or more kinds thereof.

[0023] The number average molecular weight of the polyether polyol is preferably 500 to 10,000, more preferably 700 to 7,000, and still more preferably 1,000 to 5,000. The number average molecular weight of the polyether polyol is measured as follows: heat the thermoplastic urethane-based elastomer together with water in a heated reaction vessel to hydrolyze urethane bonds, extract the polyether polyol, then measure the molecular weight in terms of polystyrene by gel permeation chromatography. An amine compound is used as a decomposition accelerator.

[0024] Examples of isocyanate compounds include aromatic diisocyanates, aliphatic diisocyanates having an aromatic ring, aliphatic diisocyanates, alicyclic diisocyanates, and other diisocyanate compounds.

[0025] Examples of aromatic diisocyanates include 2,4- or 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2,4'-MDI, paraphenylenedi diisocyanate, 1,5-naphthalene diisocyanate, and tolidine diisocyanate.

[0026] Examples of aliphatic diisocyanates having an aromatic ring include α,α,α',α'-tetramethylxylylene diisocyanate.

[0027] Examples of aliphatic diisocyanates include methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, and 1,6-hexamethylene diisocyanate.

[0028] Examples of alicyclic diisocyanates include 1,4-cyclohexane diisocyanate, methylcyclohexane diisocyanate (hydrogenated TDI), 1-isocyanate-3-isocyanate-methyl-3,5,5-trimethylcyclohexane (IPDI), 4,4'-dicyclohexylmethane diisocyanate, and isopropylidene dicyclohexyl-4,4'-diisocyanate.

[0029] The isocyanate compound may be modified in which part of the NCO group is replaced with urethane, urea, biuret, allophanate, carbodiimide, oxazolidone, amide, imide, etc., or isomers thereof.

[0030] Isocyanate compounds may be used individually or in combination of two or more compounds.

[0031] The amount of isocyanate compound used is preferably 0.1 to 5 equivalents, more preferably 0.8 to 2 equivalents, even more preferably 0.9 to 1.5 equivalents, even more preferably 0.95 to 1.2 equivalents, and even more preferably 0.98 to 1.1 equivalents, relative to 1 equivalent of the total amount of hydroxyl groups in the polyether polyol, and the hydroxyl and / or amino groups of the chain extender and other polyols used as needed, as described later.

[0032] Since isocyanate compounds react with moisture contained in polyurethane raw materials other than the isocyanate compound, such as polyether polyols and chain extenders used as needed (described later), and are partially lost, an amount to compensate for this loss may be added to the desired amount of isocyanate compound used. Specifically, for example, before mixing with the isocyanate compound during the reaction, the amount of moisture in the polyether polyol or chain extender can be measured, and an isocyanate compound having isocyanate groups equivalent to twice the amount of that moisture can be added to the predetermined amount.

[0033] The mechanism by which isocyanate groups disappear upon reaction with water is as follows: the isocyanate group reacts with water molecules to form an amine compound, and this amine compound further reacts with the isocyanate group to form a urea bond, resulting in the disappearance of two isocyanate groups for each molecule of water. This loss may result in a deficiency of the required isocyanate compound, potentially preventing the acquisition of desired physical properties. Therefore, it is effective to add an isocyanate compound to compensate for the moisture content using the method described above.

[0034] Examples of chain extenders include compounds having two or more hydroxyl groups with a molecular weight of 500 or less, compounds having two or more amino groups, and water.

[0035] Compounds having two or more hydroxyl groups include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2- Examples include aliphatic glycols such as methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; alicyclic glycols such as bishydroxymethylcyclohexane; and glycols having aromatic rings such as xylylene glycol and bishydroxyethoxybenzene. Among these, short-chain polyols with 10 or fewer carbon atoms are preferred, with ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and 2-methyl-1,3-propanediol being more preferred, and 1,4-butanediol being even more preferred from the viewpoint of having an excellent balance of physical properties in the resulting polyurethane.

[0036] Compounds having two or more amino groups include, for example, aromatic diamines such as 2,4- or 2,6-tolylenediamine, xylylenediamine, and 4,4'-diphenylmethanediamine; ethylenediamine, 1,2-propylenediamine, 2,2-dimethyl-1,3-propanediamine, 1,3-pentanediamine, 2-methyl-1,5-pentanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,6-hexanediamine, and 2,2,4- or 2,4- Examples include aliphatic diamines such as 4-trimethylhexanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine; and alicyclic diamines such as 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA), 4,4'-dicyclohexylmethanediamine (hydrogenated MDA), isopropylidenecyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, and 1,3-bisaminomethylcyclohexane. Among these, ethylenediamine, 1,2-propylenediamine, 1,3-pentanediamine, and 2-methyl-1,5-pentanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA), and 4,4'-dicyclohexylmethanediamine (hydrogenated MDA) are preferred.

[0037] Furthermore, these chain extenders can also be derived from biomass resources.

[0038] The amount of these chain extenders used is preferably 0.1 to 5.0 equivalents, more preferably 0.5 to 2.0 equivalents, even more preferably 0.8 to 1.5 equivalents, and even more preferably 0.9 to 1.5 equivalents, when the equivalent obtained by subtracting the hydroxyl group equivalent of the polyether polyol from the equivalent of the isocyanate compound is set to 1.

[0039] Commercially available polyether-based thermoplastic urethane elastomers can also be used as thermoplastic urethane elastomer B1. Examples of such commercially available products include Elastran ET-385, ET-880, ET-890 (manufactured by BASF Japan Ltd.), Huafon TPU HF-4070A, HF-4080A, HF-4390A (manufactured by Huafon Chemical Co., Ltd.), and Miractran E380, E385, E390 (manufactured by Nippon Miractran Co., Ltd.).

[0040] The A hardness of thermoplastic urethane elastomer B1 is preferably 40 to 90 points, more preferably 50 to 90 points, even more preferably 60 to 90 points, and even more preferably 70 to 90 points, from the viewpoint of flexibility.

[0041] Thermoplastic urethane elastomer B2 contains polyester polyol and isocyanate compound as constituent units and is obtained by reacting polyester polyol, isocyanate compound, and, if necessary, chain extender by conventional methods. In thermoplastic urethane elastomer B2, the portion formed by polymerization of isocyanate compound and chain extender is the hard segment, and the portion composed of polyester polyol is the soft segment.

[0042] Examples of polyester polyols include polyester diols obtained from aliphatic dicarboxylic acid components, aliphatic diol components, lactone components, etc.

[0043] Examples of aliphatic dicarboxylic acid components include aliphatic dicarboxylic acids with 4 to 12 carbon atoms, such as adipic acid.

[0044] Examples of aliphatic diol components include aliphatic diols with 2 to 12 carbon atoms, such as ethylene glycol, propylene glycol, butanediol, and neopentyl glycol.

[0045] Examples of lactone components include lactones with 4 to 12 carbon atoms, such as ε-caprolactone.

[0046] Preferred polyester polyols are aliphatic polyester diols obtained by polymerizing an aliphatic dicarboxylic acid component and an aliphatic diol component. Specifically, examples include poly(ethylene adipate), poly(1,4-butylene adipate), poly(1,6-hexane adipate), and poly-ε-caprolactone.

[0047] The number-average molecular weight of the polyester polyol is preferably 500 to 10,000, more preferably 700 to 7,000, and even more preferably 1,000 to 5,000. The number-average molecular weight of the polyester polyol is determined by heating a thermoplastic urethane elastomer with water in a heated reaction vessel to hydrolyze the urethane bonds and extract the polyester polyol, then measuring the molecular weight in terms of polystyrene by gel permeation chromatography. Pyridine is used as a decomposition accelerator.

[0048] The isocyanate compounds and chain extenders are the same as those described for thermoplastic urethane elastomer B2.

[0049] Commercially available polyester-based thermoplastic urethane elastomers can also be used as thermoplastic urethane elastomer B2. Examples of such commercially available products include Huafon TPU HF-1090AS, HF-1280AX, HF-1370A-1 (manufactured by Huafon Chemical Co., Ltd.), Elastran ET-680, ET-685, ET-690 (manufactured by BASF Japan Ltd.), and Miractran E180, E185, E190 (manufactured by Nippon Miractran Co., Ltd.).

[0050] The A hardness of thermoplastic urethane elastomer B2 is preferably 40 to 95 points, more preferably 50 to 95 points, even more preferably 60 to 95 points, and still more preferably 60 to 90 points.

[0051] In the present invention, from the viewpoint of thermal fusion properties with polar resins, the A hardness of thermoplastic urethane elastomer B2 is preferably less than or equal to the A hardness of thermoplastic urethane elastomer B1, and the difference in A hardness between thermoplastic urethane elastomer B1 and thermoplastic urethane elastomer B2 is preferably 15 points or less, more preferably 1 to 15 points, and even more preferably 2 to 10 points.

[0052] The mass ratio of thermoplastic urethane elastomer B1 to thermoplastic urethane elastomer B2 (thermoplastic urethane elastomer B1 / thermoplastic urethane elastomer B2) is preferably 1 / 99 or higher from the viewpoint of abrasion resistance, and preferably 99 / 1 or lower from the viewpoint of thermal fusion to polar resins. From these viewpoints, the mass ratio of thermoplastic urethane elastomer B1 to thermoplastic urethane elastomer B2 is preferably 1 / 99 to 99 / 1, more preferably 5 / 95 to 95 / 5, even more preferably 10 / 90 to 90 / 10, and even more preferably 20 / 80 to 80 / 20.

[0053] The total content of thermoplastic urethane elastomer B1 and thermoplastic urethane elastomer B2 is preferably 20 parts by mass or more, from the viewpoint of heat fusion to polar resins, and preferably 800 parts by mass or less, from the viewpoint of flexibility, per 100 parts by mass of thermoplastic styrene elastomer A. From these viewpoints, the total content of thermoplastic urethane elastomer B1 and thermoplastic urethane elastomer B2 is preferably 20 to 800 parts by mass, more preferably 30 to 500 parts by mass, even more preferably 50 to 400 parts by mass, even more preferably 80 to 300 parts by mass, even more preferably 100 to 300 parts by mass, and even more preferably 100 to 250 parts by mass, per 100 parts by mass of thermoplastic styrene elastomer A.

[0054] Content of thermoplastic urethane elastomer B (Total content of thermoplastic urethane elastomer B1 and thermoplastic urethane elastomer B2) The amount of this component in the thermoplastic elastomer composition is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, and even more preferably 20 to 50% by mass.

[0055] Examples of softening agent C include mineral oil-based softening agents such as paraffin oil, naphthenic oil, and asphalt oil; vegetable oil-based softening agents such as fatty oils, pine root oil, tall oil, and funthis; coal tar-based softening agents such as tars and coumarone indene resin; and liquid or low molecular weight synthetic resins such as phenolic resin low condensates, low melting point styrene resins, polybutene, and tertiary butylphenol acetylene condensates. Among these, paraffin oil is preferred from the viewpoint of preventing stickiness.

[0056] The kinematic viscosity of softener C at 40°C is such that a higher viscosity prevents volatilization during heating and melting, and also improves bleed resistance, so 30 mm 2 A value of 500mm is preferable, as a value of 500mm is preferable, and a lower value makes handling easier. 2 A value of / s or less is preferable. From these viewpoints, the kinematic viscosity of the softener C at 40°C is preferably 30 to 500 mm². 2 / s, more preferably 60-450mm 2 / s, more preferably 80-430mm 2 It is / s.

[0057] The content of softener C is preferably 10 parts by mass or more per 100 parts by mass of thermoplastic styrene elastomer A from the viewpoint of flexibility, and preferably 500 parts by mass or less from the viewpoint of preventing stickiness. From these viewpoints, the content of softener C is preferably 10 to 500 parts by mass, more preferably 20 to 400 parts by mass, even more preferably 30 to 300 parts by mass, even more preferably 40 to 200 parts by mass, and even more preferably 80 to 150 parts by mass per 100 parts by mass of thermoplastic styrene elastomer A.

[0058] The content of softener C in the thermoplastic elastomer composition is preferably 5 to 35% by mass, more preferably 10 to 30% by mass, and even more preferably 15 to 25% by mass.

[0059] From the viewpoint of improving the thermal smeltability to polar resins, the thermoplastic elastomer composition of the present invention preferably further contains a styrene-based elastomer D containing a carboxyl group or an acid anhydride group.

[0060] In the styrene-based elastomer D containing a carboxyl group or an acid anhydride group, the styrene-based elastomer can be the same as the styrene-based elastomer A mentioned above.

[0061] A styrene-based elastomer D containing a carboxyl group or acid anhydride group can be obtained, for example, by introducing a carboxyl group or acid anhydride group into a styrene-based elastomer or a hydrogenated styrene-based elastomer. The introduction of a carboxyl group or acid anhydride group can be carried out according to a method known in itself. Specifically, for example, a styrene-based elastomer can be introduced by grafting a styrene-based elastomer with an unsaturated monocarboxylic acid exemplified by acrylic acid, methacrylic acid, etc.; an unsaturated dicarboxylic acid exemplified by maleic acid, fumaric acid, hymic acid, itaconic acid, etc.; or an anhydride of an unsaturated dicarboxylic acid exemplified by maleic anhydride, hymic anhydride, itaconic anhydride, etc., in the presence of an organic peroxide, in the presence or absence of a solvent. Furthermore, styrene-based elastomers D containing a carboxyl group or acid anhydride group can also be generally available as commercially available products. For example, commercially available hydrogenated styrene elastomers with acid anhydride groups introduced using maleic anhydride include Kraton FG1901 and FG1924 from Kraton Polymers, ToughTec M1911, M1913, and M1943 from Asahi Kasei Corporation, and Globalprene 9901 from LCY Chemical Co., Ltd.

[0062] For example, if the styrene-based elastomer D containing a carboxyl group or an acid anhydride group is a styrene-based elastomer (maleic anhydride-modified styrene-based elastomer) into which an acid anhydride group has been introduced with maleic anhydride, the amount of modification by maleic anhydride (maleic anhydride content) in the maleic anhydride-modified styrene-based elastomer is preferably 0.1% by mass or more from the viewpoint of heat fusion properties with polar resins, and preferably 10% by mass or less from the viewpoint of injection moldability. From these viewpoints, the amount of modification by maleic anhydride is preferably 0.1 to 10% by mass, more preferably 0.5 to 5.0% by mass, and even more preferably 0.8 to 3.0% by mass.

[0063] The A hardness of the styrene-based elastomer D containing a carboxyl group or an acid anhydride group is preferably 50 to 90 points, more preferably 60 to 80 points, and even more preferably 65 to 75 points, from the viewpoint of flexibility.

[0064] The content of carboxyl group or acid anhydride group-containing styrene elastomer D is preferably 5% by mass or more from the viewpoint of heat fusion to polar resins, and preferably 90% by mass or less from the viewpoint of injection moldability, based on the total amount of thermoplastic styrene elastomer A and carboxyl group or acid anhydride group-containing styrene elastomer D. From these viewpoints, the content of carboxyl group or acid anhydride group-containing styrene elastomer D is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, even more preferably 10 to 70% by mass, and even more preferably 15 to 60% by mass, based on the total amount of thermoplastic styrene elastomer A and carboxyl group or acid anhydride group-containing styrene elastomer D.

[0065] The content of styrene-based elastomer D containing carboxyl groups or acid anhydride groups is preferably 1 to 20% by mass, more preferably 5 to 15% by mass, and even more preferably 8 to 12% by mass in the thermoplastic elastomer composition.

[0066] From the viewpoint of specific gravity, the thermoplastic elastomer composition of the present invention preferably further contains inorganic filler E. In particular, when used in the grip of a power tool, the specific gravity of the thermoplastic elastomer composition is preferably adjusted to 1 or higher in order to maintain a balance between the grip portion and the motor portion.

[0067] Examples of inorganic filler E include talc, mica, calcium carbonate, clay, titanium dioxide, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium oxide, iron oxide, zinc oxide, alumina, silica, diatomaceous earth, dolomite, gypsum, calcined clay, asbestos, calcium silicate, bentonite, white carbon, carbon black, iron powder, aluminum powder, stone powder, blast furnace slag, fly ash, cement, and zirconia powder. Among these, calcium carbonate is preferred from the viewpoint of economy and abrasion resistance. Alternatively, these materials may be used after being surface-treated with organic acids or silane coupling agents.

[0068] Volume-intermediate particle size (D) of inorganic filler E by wet method 50 From the viewpoint of injection moldability, the particle size (D) is preferably 0.1 μm or larger, and from the viewpoint of wear resistance, it is preferably 50 μm or smaller. From these viewpoints, the volume median particle size (D) of the inorganic filler E is preferred. 50 The particle size is preferably 0.1 to 50 μm, more preferably 0.5 to 40 μm, even more preferably 1 to 20 μm, and even more preferably 3 to 10 μm.

[0069] The content of inorganic filler E is preferably 20 parts by mass or more per 100 parts by mass of thermoplastic styrene elastomer A, from the viewpoint of specific gravity, and preferably 300 parts by mass or less from the viewpoint of abrasion resistance to polar resins. From these viewpoints, the content of inorganic filler E is preferably 20 to 300 parts by mass, more preferably 30 to 200 parts by mass, and even more preferably 40 to 150 parts by mass per 100 parts by mass of thermoplastic styrene elastomer A.

[0070] The inorganic filler E content is preferably 5 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 10 to 20% by mass in the thermoplastic elastomer composition.

[0071] The thermoplastic elastomer composition of the present invention may optionally contain various additives, to the extent that it does not impair the effects of the present invention, such as organic fillers (e.g., wood flour and cellulose powder, organic fibers), antioxidants (e.g., phenolic, sulfuric, and phosphoric), weather stabilizers, ultraviolet absorbers (e.g., benzotriazole, tridiamine, anilide, and benzophenone), heat stabilizers, anti-aging agents, light stabilizers (e.g., hindered amine and benzoate), antistatic agents, nucleating agents, pigments, adsorbents (e.g., metal oxides), metal chlorides (e.g., iron chloride and calcium chloride), hydrotalcite, aluminates, lubricants (e.g., fatty acids, higher alcohols, aliphatic amides, and aliphatic esters), flame retardants, foaming agents, and silicone compounds.

[0072] The thermoplastic elastomer composition of the present invention is obtained by mixing raw materials including thermoplastic styrene elastomer A, thermoplastic urethane elastomer B1, thermoplastic urethane elastomer B2, and softener C, and optionally carboxyl group or acid anhydride group-containing styrene elastomer D, inorganic filler E, various additives, and solidifying them by cooling.

[0073] In this invention, "mixing" is not particularly limited as long as the various components are well mixed. The various components may be dissolved in an organic solvent and mixed, or mixed by heating, melting, and kneading. However, it is preferable to mix the raw materials under conditions in which the raw materials melt, preferably under conditions in which thermoplastic styrene elastomer A and thermoplastic urethane elastomers B1 and B2 melt.

[0074] When heating, melting, and kneading, a general-purpose extruder can be used, and it is preferable to use a multi-screw extruder with two or more screws to improve the kneading state. The components may be pre-mixed using a mixing device such as a Henschel mixer and supplied from a single hopper, or each component may be charged into two hoppers and supplied while being measured using screws or the like below the hoppers.

[0075] The product obtained by mixing the raw materials constituting a thermoplastic elastomer composition can be in the form of pellets, sheets, or other shapes depending on the application. For example, it can be heated, melted, and kneaded in an extruder, extruded into strands, and then cut into cylindrical or rice-grain-shaped pellets with a cutter while being cooled in cold water. The resulting pellets are usually molded into predetermined sheet-shaped molded products or molded products by injection molding or extrusion molding. Alternatively, the melted mixture can be pelletized using a ruder or the like and used as a raw material for molding.

[0076] The A hardness of the thermoplastic elastomer composition is preferably 40 to 90 points, more preferably 50 to 80 points, even more preferably 55 to 75 points, and even more preferably 60 to 70 points, from the viewpoint of flexibility.

[0077] The thermoplastic elastomer composition of the present invention can be molded into thermoplastic elastomer articles by various known molding methods, such as extrusion molding, press molding, injection molding, calendering, hollow molding, and foam molding. Furthermore, the molded articles, such as sheets or pellets, can be further processed by thermoforming or other methods.

[0078] The thermoplastic elastomer composition of the present invention can also be used for bonding components made of different materials.

[0079] For thermally bonding thermoplastic elastomer compositions, heat can be applied using methods such as a hot press, heated roll machine, hot air generator, heated steam, ultrasonic welder, high-frequency welder, or laser.

[0080] The thermoplastic elastomer composition of the present invention exhibits high heat-sealability to polar resins, as well as high flexibility and abrasion resistance. Therefore, it can maintain sufficient grip (anti-slip) over the long term, making it particularly suitable for use as a grip material for tools with a polar resin such as nylon as the core material. Examples of such polar resins include nylon, polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS resin), mixed resins of polycarbonate and acrylonitrile-butadiene-styrene resin (so-called PC / ABS alloy resin), and resins containing these reinforced with fibers. [Examples]

[0081] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. The various physical properties of the raw materials used in the examples and comparative examples were measured by the following methods.

[0082] <Component A: Thermoplastic styrene elastomer> [Content of styrene monomer units] The content of styrene and / or styrene derivatives is determined by quantitative analysis of the characteristic groups of styrene using proton NMR measurements performed with a nuclear magnetic resonance spectrometer (BRUKER DPX-400, Germany). The content of other monomer units is also determined by proton NMR measurements.

[0083] [A hardness] A 6mm thick sheet is used, and measurements are taken at a temperature of 23°C in accordance with the method specified in JIS K 6253.

[0084] <Component B: Thermoplastic urethane elastomer> [A hardness] A 6mm thick sheet is used, and measurements are taken at a temperature of 23°C in accordance with the method specified in JIS K 6253.

[0085] <Ingredient C: Softener> [Kinematic viscosity] Measurement is performed at a temperature of 40°C in accordance with JIS K 2283.

[0086] <Component D: Maleic anhydride-modified styrenic elastomer> [Content of styrenic monomer units] Proton NMR measurement is performed using a nuclear magnetic resonance apparatus (manufactured by BRUKER, Germany, model DPX-400), and the content of styrene and / or a styrene derivative is determined by quantifying the characteristic groups of styrene. The content of other monomer units is also determined by proton NMR measurement.

[0087] [Content of maleic anhydride from graft reaction] A blend of the base material before modification and maleic anhydride is pressed using a 0.1 mm spacer, IR measurement is performed, and the characteristic carbonyl (1600 to 1900 cm -1 ) absorption and the charged amount of the organic acid are used to prepare a calibration curve, IR measurement (IR measuring instrument: FT-210 manufactured by HORIBA, Ltd.) is performed on a pressed plate of the acid-modified product, and the modification amount (maleic anhydride content) is determined.

[0088] [A hardness] Measurement is performed at a temperature of 23°C in accordance with JIS K 6253.

[0089] <Component E: Inorganic filler> [Volume median particle diameter (D 50 )] Measurement is performed by a wet method using Mastersizer 2000 manufactured by Malvem.

[0090] Examples 1 to 12 and Comparative Examples 1 to 10 (1) Preparation of thermoplastic elastomer composition (pellets) After dry-blending the raw materials shown in Tables 4 to 7 excluding Component C, Component C was impregnated therein to prepare a mixture. Thereafter, the mixture was melt-kneaded with an extruder under the following conditions, extruded into strands, cut into pieces of about 3 mm in diameter and about 3 mm in thickness by a cutter while cooling in cold water, to produce pellets of the thermoplastic elastomer composition.

[0091] [Melting and mixing conditions] Extruder: KZW32TW-60MG-NH (product name, manufactured by Technovel Co., Ltd.) Cylinder temperature: 130~220℃ Screw rotation speed: 300 r / min

[0092] The details of the raw material components used in the examples and comparative examples, as listed in Tables 4-7, are as follows.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] (2) Preparation of molded articles of thermoplastic elastomer compositions A plate measuring 2 mm thick x 125 mm wide x 125 mm long was produced by injection molding the pellets under the following conditions.

[0097] [Injection molding conditions] Injection molding machine: 100MSIII-10E (product name, manufactured by Mitsubishi Heavy Industries, Ltd.) Injection molding temperature: 200℃ Injection pressure: 30% Injection time: 3sec Mold temperature: 40℃

[0098] The thermoplastic elastomer compositions obtained in the examples and comparative examples were subjected to the measurement of A hardness and specific gravity using the following method, and their abrasion resistance and heat fusion properties were further evaluated. The results are shown in Tables 4 to 7.

[0099] [A hardness] Measurements will be taken according to JIS K 6253-3 Type A.

[0100] 〔specific gravity〕 Measurements are taken at a temperature of 23°C in accordance with JIS K 7112.

[0101] [Abrasion resistance (Taber abrasion test)] In accordance with JIS K 7204, the amount of wear loss (mg) was measured at 23°C, with an abrasion wheel of H-22 grade, a rotational speed of 72 r / min, 1000 rotations, and a load of 1000 g.

[0102] [Heat-fusible properties (adhesion test)] Nylon 6 (Novamit 1010J, manufactured by DSM Engineering Plastics Co., Ltd., size: 2 mm thick x 25 mm wide x 120 mm long) was used as the adherend. This adherend was placed in the mold of an injection molding machine, and the compositions shown in Tables 4 to 7 were injection molded under the following conditions to produce test specimens in which a 2 mm thick thermoplastic elastomer composition was fused onto the adherend as a surface layer.

[0103] <Injection molding conditions> Injection molding machine: Mitsubishi Heavy Industries, Ltd., model 100MSIII-10E Injection molding temperature: 240℃ Injection pressure: 98 MPa Injection speed: 50% Holding pressure: 20% Holding time: 10sec Injection time: 2sec Mold temperature: 40℃

[0104] Using the obtained fusion test specimens, the peel strength was measured at an ambient temperature of 23°C in accordance with JIS K6854-2 "Method for Testing Adhesive Peel Strength (180° Peel)". The thermoplastic elastomer layer was used as the surface material layer, and the polar resin (nylon 6) layer as the adherend layer. A tensile test was performed on the elastomer layer at 50 mm / min in the 180° direction, and the peel strength (unit: N / 25 mm) between the surface material layer and the adherend layer was measured.

[0105] [Table 4]

[0106] [Table 5]

[0107] [Table 6]

[0108] [Table 7]

[0109] From the above results, it can be seen that the thermoplastic elastomer compositions of Examples 1 to 12, which use both a polyether-based and a polyester-based thermoplastic urethane elastomer, possess appropriate flexibility and excellent abrasion resistance and heat-sealability to polar resins, compared to Comparative Examples 1, 2, 4, 5, and 7-10, which use either a polyether-based or polyester-based thermoplastic urethane elastomer, and Comparative Examples 3 and 6, which do not use a thermoplastic urethane elastomer. In particular, a comparison of Examples 1-4 and 5-10 shows that the heat-sealing properties are significantly improved by incorporating a styrene-based elastomer containing carboxyl groups or acid anhydride groups. Furthermore, the results from Examples 11 and 12 show that abrasion resistance is further improved when the A hardness of the polyester-based thermoplastic urethane elastomer is less than or equal to the A hardness of the polyether-based thermoplastic urethane elastomer. [Industrial applicability]

[0110] The thermoplastic elastomer composition of the present invention can be used as a grip material for hand tools such as screwdrivers and hammers, and for power tools such as electric drills, electric saws, and nail guns.

Claims

1. A thermoplastic elastomer composition comprising a thermoplastic styrene elastomer A, a thermoplastic urethane elastomer B1, a thermoplastic urethane elastomer B2, and a softener C, wherein the thermoplastic urethane elastomer B1 contains a polyether polyol and an isocyanate compound as constituent units, the thermoplastic urethane elastomer B2 contains a polyester polyol and an isocyanate compound as constituent units, the content of the thermoplastic styrene elastomer A is 5 to 50% by mass, the total content of the thermoplastic urethane elastomer B1 and the thermoplastic urethane elastomer B2 is 20 to 50% by mass, and the content of the softener C is 15 to 25% by mass.

2. The thermoplastic elastomer composition according to claim 1, wherein the mass ratio of thermoplastic urethane elastomer B1 to thermoplastic urethane elastomer B2 is 20 / 80 to 80 / 20.

3. The thermoplastic elastomer composition according to claim 1 or 2, wherein the total content of thermoplastic urethane elastomer B1 and thermoplastic urethane elastomer B2 is 80 to 300 parts by mass per 100 parts by mass of thermoplastic styrene elastomer A.

4. Furthermore, the thermoplastic elastomer composition according to claim 1 or 2, further comprising a styrene-based elastomer D containing a carboxyl group or an acid anhydride group.

5. The thermoplastic elastomer composition according to claim 1 or 2, wherein the A hardness of thermoplastic urethane elastomer B1 is 40 to 90 points, and the A hardness of thermoplastic urethane elastomer B2 is 1 to 15 points lower than the A hardness of thermoplastic urethane elastomer B1.

6. The thermoplastic elastomer composition according to claim 1 or 2, wherein the thermoplastic elastomer composition is for use as a grip material for a hand tool selected from a screwdriver and a hammer, or for a power tool.

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