Thermoplastic elastomer composition

Abstract

To provide a thermoplastic elastomer composition capable of producing a molded article having a good appearance such as surface smoothness and excellent bondability to another member.SOLUTION: The thermoplastic elastomer composition comprises: an ethylene-based polymer (A); and a propylene-based polymer (B), where a melt viscosity of the thermoplastic elastomer composition measured at a temperature of 220°C and a shear rate of 12 sec-1 is 2,500 Pa sec or less; the thermoplastic elastomer composition has a sea-island structure; and an island portion has a volume average particle diameter of 2.1 μm or more and a particle diameter dispersion D of 7.0 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoplastic elastomer composition.

Background Art

[0002] Thermoplastic elastomer compositions are widely used as materials for automotive parts and the like because they are rich in recyclability, suitable for injection molding, and excellent in product performance such as strength and flexibility (see, for example, Patent Document 1). As the uses of thermoplastic elastomer compositions expand, further improvements have been demanded for various performances such as the appearance of molded products such as surface smoothness and the bondability with other members.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Under such circumstances, the problem to be solved by the present invention is to provide a thermoplastic elastomer composition capable of producing a molded body having good appearance of a molded product such as surface smoothness and excellent bondability with other members.

Means for Solving the Problems

[0005] The present inventors have made intensive studies in view of such a background and have completed the present invention. That is, the present invention is [1] (A) A thermoplastic elastomer composition containing an ethylene-based polymer and (B) a propylene-based polymer, at a temperature of 220°C and a shear rate of 12 sec -1 the melt viscosity of the thermoplastic elastomer composition is 2500 Pa·sec or less, The thermoplastic elastomer composition has a sea-island structure, and the volume-average particle diameter of the island phase is 2.1 μm or more, and the particle size dispersion D is 7.0 or less. The thermoplastic elastomer composition relates to.

[0006] Hereinafter, [2] to

[13] are respectively preferred embodiments or implementation forms of the present invention. [2] Furthermore, it contains (D) mineral oil, and the (A) ethylene-based polymer is oil-extended with (D) mineral oil. The thermoplastic elastomer composition according to [1]. [3] (A) The Mooney viscosity (ML 1+4 100 °C) of the ethylene-based polymer is 40 or more. The thermoplastic elastomer composition according to [1]. [4] (A) The Mooney viscosity (ML 1+4 100 °C) of the oil-extended polymer composed of the ethylene-based polymer and (D) mineral oil is 40 or more. The thermoplastic elastomer composition according to [2]. [5] A method for producing a thermoplastic elastomer composition, including a step of melt-kneading (A) an ethylene-based polymer and (B) a propylene-based polymer in the presence of (C) a cross-linking agent, (A) The Mooney viscosity (ML 1+4 100 °C) of the ethylene-based polymer is 40 or more, and the melt flow rate of (B) the propylene-based polymer measured under the conditions of a temperature of 230 °C and a load of 21.18 N is 1.0 to 200 g / 10 minutes. The above production method. [6] In the above step, the specific energy defined by the power consumption (kW) / discharge amount (kg / h) by melt-kneading is 0.27 (kWh / kg) or less. The method for producing a thermoplastic elastomer composition according to [5]. [7] A method for producing a thermoplastic elastomer composition, including a step of melt-kneading an oil-extended polymer and (B) a propylene-based polymer in the presence of (C) a cross-linking agent, The oil-extended polymer is composed of (A) an ethylene-based polymer and (D) mineral oil, Mooney viscosity (ML 1+4 of the oil-extended polymer at 100 °C) is 40 or more, and (B) the melt flow rate of the propylene-based polymer measured under the conditions of a temperature of 230 °C and a load of 21.18 N is 1.0 to 200 g / 10 min, the above production method. [8] The production method of the thermoplastic elastomer composition according to [7], wherein the specific energy defined by the power consumption (kW) / discharge amount (kg / h) by melt kneading in the above step is 0.27 (kWh / kg) or less. [9] The production method of the thermoplastic elastomer composition according to [5] or [6], wherein the thermoplastic elastomer composition according to [1] or [3] is produced.

[10] The production method of the thermoplastic elastomer composition according to [7] or [8], wherein the thermoplastic elastomer composition according to [2] or [4] is produced.

[11] An injection molded article comprising the thermoplastic elastomer composition according to any one of [1] to [4].

[12] A composite molded article obtained by joining the injection molded article according to

[11] and an extrusion molded article comprising a thermoplastic elastomer composition.

[13] The composite molded article according to

[12] , which is a glass runner channel. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a thermoplastic elastomer composition capable of producing a molded article having good appearance of the molded article such as surface smoothness and excellent joining property with other members. [Embodiments for Carrying Out the Invention]

[0008] The present invention is (A) A thermoplastic elastomer composition containing an ethylene-based polymer and (B) a propylene-based polymer, at a temperature of 220 °C and a shear rate of 12 sec -1The melt viscosity of the thermoplastic elastomer composition at [specific condition] is 2500 Pa·sec or less, The thermoplastic elastomer composition has a sea-island structure, and is a thermoplastic elastomer composition in which the volume average particle diameter of the island phase is 2.1 μm or more and the particle size dispersion D is 7.0 or less. That is, the thermoplastic resin composition of the present invention contains the following components (A) and (B).

[0009] (A) Ethylene polymer The thermoplastic elastomer composition of the present invention contains (A) an ethylene-based polymer. (A) The ethylene-based polymer is a polymer containing 50 mass% or more of structural units derived from ethylene. Since it contains 50 mass% or more of structural units derived from ethylene, it is a crosslinkable polymer and is suitable for forming the island phase of the sea-island structure of the thermoplastic elastomer composition by dynamic crosslinking. (A) As the ethylene-based polymer, only one kind of polymer containing 50 mass% or more of structural units derived from ethylene may be used, or two or more kinds may be used in combination. (A) The ethylene-based polymer is not particularly limited as long as it contains 50 mass% or more of structural units derived from ethylene, but it is preferable to use the following component (A1) ethylene random copolymer and / or (A2) ethylene·α-olefin·non-conjugated diene copolymer.

[0010] (A1) Ethylene random copolymer (A1) The ethylene random copolymer preferably used as the (A) ethylene-based polymer constituting the thermoplastic elastomer composition of the present invention is an ethylene random copolymer having 50 mass% or more and 90 mass% or less of structural units derived from ethylene and structural units derived from at least one monomer selected from the group consisting of α-olefins having 3 to 10 carbon atoms (however, the total amount of the ethylene random copolymer is 100 mass%). (A1) The ethylene random copolymer may have structural units derived from monomers other than ethylene and at least one selected from the group consisting of α-olefins having 3 to 10 carbon atoms.

[0011] Examples of the α-olefin having 3 to 10 carbon atoms include propylene, 1-butene, 2-methylpropene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. In the preparation of the (A1) ethylene random copolymer, the α-olefin having 3 to 10 carbon atoms may be used alone or in combination of two or more. Examples of the structural unit derived from at least one selected from the group consisting of α-olefins having 3 to 10 carbon atoms preferably include a structural unit derived from propylene, a structural unit derived from 1-butene, or a structural unit derived from 1-octene.

[0012] (A1) The content of the structural unit derived from ethylene in the ethylene random copolymer is 50% by mass or more and 90% by mass or less, preferably 55% by mass or more and 85% by mass or less, more preferably 60% by mass or more and 75% by mass or less (however, the total amount of the (A1) ethylene random copolymer is taken as 100% by mass). (A1) The content of the structural unit derived from at least one selected from the group consisting of α-olefins having 3 to 10 carbon atoms in the ethylene random copolymer is 10% by mass or more and 50% by mass or less, preferably 15% by mass or more and 45% by mass or less, more preferably 25% by mass or more and 40% by mass or less (however, the total amount of the (A1) ethylene random copolymer is taken as 100% by mass).

[0013] (A1) The content of the structural unit derived from ethylene in the ethylene random copolymer and the content of the structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 to 10 carbon atoms can be determined by infrared spectroscopy. Specifically, using an infrared spectrophotometer, the infrared absorption spectrum of the (A1) ethylene random copolymer is measured, and according to the method described in "Characterization of Polyethylene by Infrared Absorption Spectrum (written by Takayama, Usami, etc.)" or "Die Makromolekulare Chemie, 177, 461 (1976) (written by McRae, M.A., MadamS, W.F., etc.)", the content of the structural unit derived from ethylene and the content of the structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 to 10 carbon atoms are calculated. The content of the structural unit derived from ethylene and the content of the structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 to 10 carbon atoms in the component (A1-1) and component (A1-2) described below can also be determined in the same manner.

[0014] (A1) The ethylene random copolymer may have a structural unit derived from at least one monomer other than ethylene and an α-olefin having 3 to 10 carbon atoms. Examples of the other monomers include conjugated dienes having 4 to 8 carbon atoms such as 1,3-butadiene, 2-methyl-1,3-butadiene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene; non-conjugated dienes having 5 to 15 carbon atoms such as dicyclopentadiene, 5-ethylidene-2-norbornene, 1,4-hexadiene, 1,5-dicyclooctadiene, 7-methyl-1,6-octadiene, and 5-vinyl-2-norbornene; vinyl carboxylates such as vinyl acetate; unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, and ethyl methacrylate; and unsaturated carboxylic acids such as acrylic acid and methacrylic acid. The other monomer is preferably a non-conjugated diene having 5 to 15 carbon atoms, more preferably 5-ethylidene-2-norbornene or dicyclopentadiene. The (A1) ethylene random copolymer may contain two or more structural units derived from the other monomers.

[0015] (A1) When the ethylene random copolymer has a structural unit derived from at least one monomer other than ethylene and an α-olefin having 3 to 10 carbon atoms, the content of the structural unit derived from the other monomer is preferably 30% by mass or less, more preferably 20% by mass or less (provided that the total amount of the (A1) ethylene random copolymer is 100% by mass). The content of the structural unit derived from the other monomer can be determined by infrared spectroscopy. Specifically, using an infrared spectrophotometer, the peak intensity of the peak derived from the other monomer of the (A1) ethylene random copolymer is measured, and the content of the structural unit derived from the other monomer in the (A1) ethylene random copolymer is calculated from the peak intensity. The content of the structural unit derived from the other monomer in the components (A1-1) and (A1-2) described below can be determined in the same manner.

[0016] (A1) Examples of the ethylene random copolymer include ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-propylene-1-butene copolymer, ethylene-propylene-1-hexene copolymer, ethylene-propylene-1-octene copolymer, ethylene-propylene-5-ethylidene-2-norbornene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-1,4-hexadiene copolymer, ethylene-propylene-5-vinyl-2-norbornene copolymer, and the like. The ethylene random copolymer as component (A1) may be used alone or in combination of two or more. As component (A1), preferably an ethylene-propylene copolymer or an ethylene-propylene-5-ethylidene-2-norbornene copolymer can be used.

[0017] Preferred examples of the ethylene random copolymer (A1) include the following ethylene random copolymer (A1-1) and the following ethylene random copolymer (A1-2).

[0018] The ethylene random copolymer (A1-1) (hereinafter sometimes referred to as component (A1-1)) has a structural unit derived from ethylene in an amount of 50% by mass or more and 90% by mass or less, and a structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 to 10 carbon atoms, and is an ethylene random copolymer having a gel fraction of more than 10% by mass (however, the total amount of the ethylene random copolymer is taken as 100% by mass). Component (A1-1) may have a structural unit derived from a monomer other than ethylene and at least one selected from the group consisting of α-olefins having 3 to 10 carbon atoms. Specific examples of the α-olefins having 3 to 10 carbon atoms in component (A1-1), the preferred range of the content of the structural unit derived from ethylene in component (A1-1), the preferred range of the content of the structural unit derived from at least one selected from the group consisting of α-olefins having 3 to 10 carbon atoms, specific examples of the structural unit derived from a monomer other than ethylene and at least one selected from the group consisting of ethylene and α-olefins having 3 to 10 carbon atoms, the preferred range of the content of the other monomer, and specific examples of the ethylene random copolymer are the same as those of (A1) ethylene random copolymer.

[0019] The greater the amount of cross-linked structure in the ethylene random copolymer, the greater the gel fraction. Component (A1-1) can be obtained by cross-linking component (A1-2) described below. The gel fraction of component (A1-1) can be determined by the following method from the gel mass of the thermoplastic elastomer composition containing component (A1-1) and the mass of component (A1-2) contained in the raw materials of the thermoplastic elastomer composition. The gel fraction of component (A1-1) is determined by the method described below using a Soxhlet extractor in which an extraction tube is connected to the lower part of a reflux condenser and a flask is connected to the lower part of the extraction tube. Weigh approximately 1 g of the thermoplastic elastomer composition and an empty wire cage made of a wire mesh (mesh size: 400 mesh) respectively. Introduce the wire cage enclosing the thermoplastic elastomer composition into the extraction tube. Introduce 300 ml of o-xylene into the flask. Heat the flask and reflux the o-xylene for 24 hours for extraction. After extraction, take out the wire cage containing the extraction residue from the test tube, perform drying under reduced pressure at 100 °C using a vacuum dryer, and weigh the wire cage containing the extraction residue after drying. The gel mass of the thermoplastic elastomer composition is calculated from the mass difference between the wire cage containing the extraction residue after drying and the empty wire cage. The gel fraction (mass %) of component (A1-1) is calculated based on the following formula. Gel fraction of component (A1-1) = (Gel mass of thermoplastic elastomer composition / Mass of component (A1-2)) × 100 The gel fraction of component (A1-1) is preferably 20% by mass or more, more preferably 40% by mass or more. The more the ethylene random copolymer has a crosslinked structure, the larger the gel fraction of the thermoplastic elastomer composition becomes. From the gel mass of the thermoplastic elastomer composition determined by the same method as above, the gel fraction of the thermoplastic elastomer composition can be calculated by the following formula. Gel fraction of thermoplastic elastomer composition = (Gel mass of thermoplastic elastomer composition / Mass of thermoplastic elastomer composition) × 100 The gel fraction of the thermoplastic elastomer composition is preferably 10% by mass or more and 90% by mass or less, more preferably 15% by mass or more and 60% by mass or less, still more preferably 18% by mass or more and 40% by mass or less.

[0020] Component (A1-1) can be obtained by crosslinking the following-described component (A1-2). Examples of the crosslinking method include a method of melt-kneading a composition containing component (A1-2) and the following-described crosslinking agent (C). The crosslinking may be carried out simultaneously when producing the thermoplastic elastomer composition of the present invention. In that case, by melt-kneading a composition containing component (A1-2), the following-described (B) propylene-based polymer, and (C) crosslinking agent, a composition containing component (A1-1) and (B) propylene-based polymer can be produced, and the details are as described below.

[0021] The ethylene random copolymer (A1-2) (hereinafter sometimes referred to as component (A1-2)) has a structural unit derived from ethylene in an amount of 50% by mass or more and 90% by mass or less, and a structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 to 10 carbon atoms, and is an ethylene random copolymer having a gel fraction of 10% by mass or less (where the total amount of the ethylene random copolymer is 100% by mass). Component (A1-2) may have a structural unit derived from a monomer other than at least one selected from the group consisting of ethylene and α-olefins having 3 to 10 carbon atoms. Specific examples of the α-olefins having 3 to 10 carbon atoms in component (A1-2), the preferable range of the content of the structural unit derived from ethylene in component (A1-2), the preferable range of the content of the structural unit derived from at least one selected from the group consisting of α-olefins having 3 to 10 carbon atoms, specific examples of the structural unit derived from a monomer other than at least one selected from the group consisting of ethylene and α-olefins having 3 to 10 carbon atoms, the preferable range of the content of the other monomer, and specific examples of the ethylene random copolymer are the same as in the case of (A1) ethylene random copolymer.

[0022] The gel fraction of component (A1-2) is preferably 5% by mass or less, more preferably 0 part by mass. Component (A1-2) preferably has substantially no crosslinked structure.

[0023] The Mooney viscosity (ML 1+4 100℃) of component (A1-2) measured at 100 °C is preferably 5 or more and 300 or less, more preferably 10 or more and 250 or less, and still more preferably 40 or more and 200 or less. The Mooney viscosity (ML 1+4 100℃) is measured according to JIS K6300, and "ML 1+4 100℃" has the following meaning. M: Mooney viscosity L: Use a large rotor 100℃: Measurement temperature 1+4: The measured value when the sample is heated for 1 minute and then the rotor is rotated at 2 rpm for 4 minutes

[0024] As a method for producing component (A1-2), a method of copolymerizing ethylene with at least one monomer selected from the group consisting of ethylene and an α-olefin having 3 to 10 carbon atoms in the presence of a known coordination catalyst such as a Ziegler-Natta catalyst, a metallocene complex, or a non-metallocene complex can be mentioned. Examples of the polymerization method include a slurry polymerization method, a solution polymerization method, a bulk polymerization method, and a gas phase polymerization method.

[0025] (A2) Ethylene·α-olefin·non-conjugated diene copolymer (A2) An ethylene-α-olefin-non-conjugated diene copolymer preferably used as the ethylene-based polymer has a non-conjugated diene unit content of preferably 4 to 15 wt%, more preferably 6 to 15 wt%. The (A2) ethylene-α-olefin-non-conjugated diene copolymer in the present embodiment is an ethylene-α-olefin-non-conjugated diene copolymer rubber having an A hardness of 85 or less according to JIS K6253.

[0026] As the above α-olefin, an α-olefin having 3 to 20 carbon atoms is preferable, and examples include propylene, 1-butene, 2-methylpropylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene; and combinations of two or more of these can be exemplified. Among them, from the viewpoint of availability, propylene or 1-butene is preferable, and propylene is more preferable.

[0027] Examples of the non-conjugated diene include chain non-conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, and 7-methyl-1,6-octadiene; and cyclic non-conjugated dienes such as cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, and 6-chloromethyl-5-isopropenyl-2-norbornene; and trienes such as 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, and 4-ethylidene-8-methyl-1,7-nonadiene. Among them, 5-ethylidene-2-norbornene or dicyclopentadiene is preferred.

[0028] (A2) When the total amount of ethylene units, α-olefin units having 3 to 20 carbon atoms, and non-conjugated diene units contained in the ethylene-α-olefin-non-conjugated diene copolymer is 100% by mass, the amount of ethylene units contained in the (A2) ethylene-α-olefin-non-conjugated diene copolymer is usually 30 to 80% by mass, preferably 40 to 80% by mass, and the amount of α-olefin units having 3 to 20 carbon atoms is usually 5 to 50% by mass, preferably 15 to 45% by mass. The amount of non-conjugated diene units contained in the (A2) ethylene-α-olefin-non-conjugated diene copolymer is 4 to 15% by mass, preferably 6 to 15% by mass (the total of these three types of constitutional units is 100% by mass). Specific examples of preferred (A2) ethylene-α-olefin-non-conjugated diene copolymers include ethylene-propylene-5-ethylidene-2-norbornene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-1,4-hexadiene copolymer, and ethylene-propylene-5-vinyl-2-norbornene copolymer; and combinations of two or more of these can be exemplified. Among them, an ethylene-propylene-5-ethylidene-2-norbornene copolymer having an ethylene unit content of 40 to 80% by mass, a propylene unit content of 15 to 45% by mass, and a 5-ethylidene-2-norbornene unit content of 6 to 15% by mass is preferred.

[0029] (A2) The amounts of ethylene units, α-olefin units having 3 to 20 carbon atoms, and non-conjugated diene units contained in the ethylene-α-olefin-non-conjugated diene copolymer can be determined by infrared spectroscopy (IR method). Specifically, the (A2) ethylene-α-olefin-non-conjugated diene copolymer is formed into a film with a thickness of about 0.5 mm, and then, using an infrared spectrophotometer, the peak derived from 5-ethylidene-2-norbornene of the film (1688 cm -1Measure the absorption peak (of [substance name not provided]) to calculate the amount of 5-ethylidene-2-norbornene units in the copolymer. Next, form the copolymer into a film with a thickness of about 0.1 mm, measure the infrared absorption spectrum of the film using an infrared spectrophotometer, and determine the ratio of ethylene units to propylene units according to the method described in the literature (Characterization of Polyethylene by Infrared Absorption Spectrum, written by Takayama, Usami, etc. or Die Makromolekulare Chemie, 177, 461 (1976), written by Mc Rae, M.A., MadamS, W.F., etc.). From this ratio and the amount of 5-ethylidene-2-norbornene units, the amounts of ethylene units and propylene units can be calculated.

[0030] (A2) The ethylene·α-olefin·non-conjugated diene copolymer can be obtained by polymerization using a known method. Examples of such polymerization methods include polymerization in an inert solvent such as hexane, heptane, toluene, or xylene using a polymerization catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.

[0031] (A2) The Mooney viscosity (ML 1+4 at 100 °C) of the ethylene·α-olefin·non-conjugated diene copolymer is preferably 5 or more and 300 or less, more preferably 10 or more and 250 or less, and even more preferably 50 or more and 200 or less. An olefin-based thermoplastic elastomer composition obtained using an (A2) ethylene·α-olefin·non-conjugated diene copolymer with a Mooney viscosity within the above range can provide a molded product with excellent mechanical strength and extremely good appearance when molded. The Mooney viscosity (ML 1+4 at 100 °C) is measured according to JIS K6300.

[0032] (B) Propylene polymer The thermoplastic elastomer composition of the present invention contains (B) a propylene-based polymer. The (B) propylene polymer contained in the thermoplastic elastomer composition according to the present invention (hereinafter sometimes referred to as component (B)) is a propylene (co)polymer having structural units derived from propylene of more than 50% by mass and 100% by mass or less. Component (B) may have structural units derived from monomers other than propylene. Since it contains 50% by mass or more of structural units derived from propylene, it is a non-crosslinkable or decomposable polymer compared to component (A), and is suitable for constituting the sea phase of the sea-island structure of the thermoplastic elastomer composition.

[0033] Examples of monomers other than propylene include ethylene and α-olefins having 4 or more carbon atoms, and ethylene and α-olefins having 4 or more and 20 or less carbon atoms are preferred. Examples of α-olefins having 4 or more and 20 or less carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, 2,2,4-trimethyl-1-pentene, and the like. The content of the structural unit derived from propylene, the content of the structural unit derived from ethylene, and the content of the structural unit derived from at least one monomer selected from the group consisting of α-olefins having 4 or more carbon atoms in the (B) propylene-based polymer can be determined by the same method as the content of each structural unit in the (A) ethylene-based polymer.

[0034] Examples of the (B) propylene-based polymer include a propylene homopolymer, a propylene random copolymer, and a heterophasic propylene polymerization material. The thermoplastic elastomer composition according to the present invention may contain only one kind of the (B) propylene-based polymer or may contain two or more kinds.

[0035] Examples of preferred propylene random copolymers include, for example, (1) A propylene-ethylene random copolymer in which the content of the structural unit derived from propylene is 90% by mass or more and 99.5% by mass or less, and the content of the structural unit derived from ethylene is 0.5% by mass or more and 10% by mass or less (the total amount of the structural unit derived from propylene and the structural unit derived from ethylene is 100% by mass); (2) A propylene-ethylene-α-olefin random copolymer in which the content of propylene units is 81% by mass or more and 99% by mass or less, the content of the structural unit derived from ethylene is 0.5% by mass or more and 9.5% by mass or less, and the content of the structural unit derived from an α-olefin having 4 to 10 carbon atoms is 0.5% by mass or more and 9.5% by mass or less (the total amount of the structural unit derived from propylene, the structural unit derived from ethylene, and the structural unit derived from an α-olefin having 4 to 10 carbon atoms is 100% by mass); (3) A propylene-α-olefin random copolymer in which the content of the structural unit derived from propylene is 90% by mass or more and 99.5% by mass or less, and the content of the structural unit derived from an α-olefin having 4 to 10 carbon atoms is 0.5% by mass or more and 10% by mass or less (provided that the total amount of the structural unit derived from propylene and the structural unit derived from an α-olefin having 4 to 10 carbon atoms is 100% by mass). Examples of the α-olefin having 4 to 10 carbon atoms in the above (1) and (2) include linear α-olefins such as 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene; and branched α-olefins such as 3-methyl-1-butene and 3-methyl-1-pentene. In the preparation of the above (1) and (2), the α-olefin having 4 to 10 carbon atoms may be used alone or in combination of two or more.

[0036] Examples of the production methods of a propylene homopolymer and a propylene random copolymer include methods of polymerizing propylene (and other monomers as required) in the presence of a Ziegler-Natta catalyst or a complex catalyst such as a metallocene complex or a non-metallocene complex. Examples of the polymerization method include a slurry polymerization method, a solution polymerization method, a bulk polymerization method, and a gas phase polymerization method.

[0037] As used herein, the term "heterophagic propylene polymer material" means a mixture having a structure in which a copolymer (II) (wherein the total mass of the copolymer is 100% by mass) (hereinafter sometimes simply referred to as "copolymer (II)") having a structural unit derived from ethylene of 20% by mass or more and 90% by mass or less and a structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 or more carbon atoms is dispersed in a matrix of a polymer (I) (wherein the total mass of the polymer is 100% by mass) (hereinafter sometimes simply referred to as "polymer (I)") having a structural unit derived from propylene of more than 80% by mass and 100% by mass or less. ) is dispersed. The heterophagic propylene polymer material as component (B) has a structural unit derived from propylene of 50% by mass or more based on the total amount of the heterophagic propylene polymer material being 100% by mass. The content of the polymer (I) contained in the heterophagic propylene polymer material is preferably 70% by mass or more and 90% by mass or less, more preferably 75% by mass or more and 90% by mass or less (wherein the total amount of the heterophagic propylene polymer material is 100% by mass). The content of the copolymer (II) contained in the heterophagic propylene polymer material is preferably 10% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less (wherein the total amount of the heterophagic propylene polymer material is 100% by mass).

[0038] Examples of the α-olefin having 3 or more carbon atoms in the copolymer (II) include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, 2,2,4-trimethyl-1-pentene and the like. The α-olefin having 3 or more carbon atoms is preferably an α-olefin having 3 to 20 carbon atoms, more preferably an α-olefin having 3 to 10 carbon atoms, and still more preferably propylene, 1-butene, 1-hexene, or 1-octene. In the copolymer (II), the α-olefin having 3 or more carbon atoms may be used alone or in combination of two or more.

[0039] The content of the structural unit derived from ethylene contained in the copolymer (II) is preferably 22% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less, and still more preferably 27% by mass or more and 60% by mass or less (however, the total amount of the structural unit derived from at least one selected from the group consisting of α-olefins having 3 or more carbon atoms and the structural unit derived from ethylene is 100% by mass). The content of the structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 or more carbon atoms contained in the copolymer (II) is preferably 20% by mass or more and 78% by mass or less, more preferably 30% by mass or more and 75% by mass or less, and still more preferably 40% by mass or more and 73% by mass or less (however, the total amount of the structural unit derived from at least one monomer selected from the group consisting of α-olefins having 3 or more carbon atoms and the structural unit derived from ethylene is 100% by mass).

[0040] Examples of the copolymer (II) include propylene-ethylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, propylene-ethylene-1-octene copolymer, etc., and propylene-ethylene copolymer or propylene-ethylene-1-butene copolymer is preferred. The copolymer (II) is usually a random copolymer.

[0041] Examples of the method for producing the heterophagic propylene polymerization material as the component (B) include a method of multi-stage polymerizing monomers including propylene and ethylene in the presence of a polymerization catalyst. For example, using a polymerization catalyst, in the first polymerization step, a monomer containing propylene is polymerized in the presence of the polymerization catalyst to produce a polymer (I), and in the second polymerization step, in the presence of the polymer (I) obtained in the first polymerization step, ethylene and at least one monomer selected from the group consisting of α-olefins having 3 or more carbon atoms are copolymerized to produce a copolymer (II). Examples of the polymerization catalyst used for the production of the heterophagic propylene polymerization material include Ziegler catalysts, Ziegler-Natta catalysts, catalysts composed of a transition metal compound of Group 4 of the periodic table having a cyclopentadienyl ring and an alkylaluminoxane, a transition metal compound of Group 4 of the periodic table having a cyclopentadienyl ring, a compound that reacts with the transition metal compound to form an ionic complex, and catalysts composed of an organoaluminum compound. Further, a prepolymerization catalyst may be used in the presence of the above polymerization catalyst. Examples of the prepolymerization catalyst include the catalysts described in JP-A-61-218606, JP-A-61-287904, JP-A-5-194685, JP-A-7-216017, JP-A-9-316147, JP-A-10-212319, and JP-A-2004-182981.

[0042] Examples of the polymerization method in the production of the heterophasic propylene polymerization material as component (B) include bulk polymerization, solution polymerization, slurry polymerization, gas phase polymerization, etc. Examples of the inert hydrocarbon solvent used in solution polymerization and slurry polymerization include propane, butane, isobutane, pentane, hexane, heptane, octane, etc. These polymerization methods may be combined in two or more, and may be either batch type or continuous type. As the polymerization method in the production of the heterophasic propylene polymerization material, continuous gas phase polymerization and bulk-gas phase polymerization in which bulk polymerization and gas phase polymerization are continuously carried out are preferred.

[0043] The melt flow rate (MFR) of the propylene-based polymer (B) measured under the conditions of a temperature of 230 °C and a load of 21.18 N in accordance with JIS K7210 is preferably 1.0 g / 10 min or more and 200 g / 10 min or less from the viewpoint of the bondability with other members. The melt flow rate of the propylene-based polymer (B) is more preferably 4.0 g / 10 min or more and 150 g / 10 min or less, and still more preferably 10 g / 10 min or more and 105 g / 10 min or less.

[0044] The intrinsic viscosity (hereinafter referred to as [η cxis ) of the insoluble part of the propylene-based polymer (B) in xylene at 20 °C (hereinafter referred to as the CXIS part) is preferably 0.1 dl / g or more and 6.0 dl / g or less, more preferably 0.3 dl / g or more and 5.0 dl / g or less, and still more preferably 0.3 dl / g or more and 2.9 dl / g or less. The intrinsic viscosity can be determined according to the following procedure. Using an Ubbelohde viscometer, the reduced viscosity is measured in tetralin at 135 °C, and from the obtained reduced viscosity, the intrinsic viscosity is determined by the extrapolation method according to the calculation method described on page 491 of "Polymer Solutions, Polymer Experimental Chemistry 11" (published by Kyoritsu Shuppan Co., Ltd. in 1982). Here, the CXS part and the CXIS part are obtained by the following method. (B) Approximately 5 g of a propylene-based polymer is completely dissolved in 500 ml of boiling xylene. The obtained xylene solution is gradually cooled to 20°C, adjusted at 20°C for 4 hours or more, and the precipitate and the solution are filtered. The precipitate is the CXIS part. Note that the material obtained by removing the solvent from the solution is the xylene-soluble part (CXS part) at 20°C.

[0045] (B) The propylene-based polymer is preferably a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-ethylene-1-butene random copolymer, or a heterophasic propylene polymerization material, and particularly preferably a propylene homopolymer, an ethylene-propylene random copolymer, or a heterophasic propylene polymerization material.

[0046] (C) Crosslinking agent The thermoplastic elastomer composition of the present invention having a sea-island structure is preferably produced through a step of melt-kneading (A) an ethylene-based polymer and (B) a propylene-based polymer in the presence of (C) a crosslinking agent. As the (C) crosslinking agent preferably used in this embodiment, a crosslinking agent commonly used for crosslinking rubber can be used, and examples thereof include organic peroxides, phenolic resins, sulfur, sulfur-containing compounds, p-quinone, derivatives of p-quinone dioxime, bismaleimide compounds, epoxy compounds, silane compounds, and amino resins. Among them, organic peroxides are preferred.

[0047] Examples of the organic peroxide include ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, percarbonates, peroxydicarbonates, peroxy esters, and the like. Specific organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne, 1,3-bis(tert-butylperoxyisopropyl)benzene, tert-butyl cumyl peroxide, di-tert-butyl peroxide, 2,2,4-trimethylpentyl-2-hydroperoxide, diisopropylbenzene hydroperoxide, cumene peroxide, tert-butyl peroxide, 1,1-di(tert-butylperoxy)3,5,5-trimethylcyclohexane, 1,1-di-tert-butylperoxycyclohexane, isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, and the like. The organic peroxide may be used alone or in combination of two or more.

[0048] The organic peroxide used in this embodiment may be in any form such as liquid, powder, pellet, etc. Further, in order to improve the dispersibility, it is more preferable to dilute the organic peroxide with a diluent such as an inorganic filler, mineral oil, or solvent that is inert to the crosslinking reaction and use it. Also, it is more preferable to add it in a liquid state. Among them, paraffinic oil is a preferable diluent in consideration of its handleability and the influence on the product.

[0049] In order to make the crosslinking reaction proceed uniformly and gently, an organic peroxide may be used in combination with a crosslinking aid. As the crosslinking aid, polyfunctional compounds such as sulfur-based, methacrylate-based, and maleimide-based compounds can be blended. Examples of the crosslinking aid include sulfur, p-quinonedioxime, p,p'-dibenzoylquinonedioxime, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, diallyl phthalate, tetraallyloxyethane, triallyl isocyanurate, N,N'-m-phenylenebismaleimide, maleic anhydride, divinylbenzene, zinc diacrylate, and zinc dimethacrylate. Among them, N,N'-m-phenylenebismaleimide, p,p'-dibenzoylquinonedioxime, divinylbenzene, trimethylolpropane trimethacrylate, or triallyl isocyanurate is preferred. N,N'-m-phenylenebismaleimide can also be used alone as a crosslinking agent.

[0050] (C) Examples of the phenolic resin used as the crosslinking agent include compounds represented by the following formula, which are generally used as crosslinking agents for rubber (see U.S. Patent Nos. 3,287,440 and 3,709,840):

Chemical formula

[0051] Examples of the above phenolic resin also include alkylphenol-formaldehyde and brominated alkylphenol-formaldehyde. When using a phenolic resin as a crosslinking agent, it may be combined with a crosslinking accelerator to adjust the rate of the crosslinking reaction. Examples of the crosslinking accelerator include metal halides such as stannous chloride and ferric chloride; and organic halides such as chlorinated polypropylene, butyl rubber bromide, and chloroprene rubber. The phenolic resin is preferably used in combination with a dispersant such as a metal oxide (e.g., zinc oxide) and stearic acid.

[0052] (C) There is no particular limitation on the addition amount of the crosslinking agent, and those skilled in the art can appropriately set the addition amount of the (C) crosslinking agent suitable for crosslinking the (A) ethylene-based polymer, etc. to a desired level. (C) Since the crosslinking agent may decompose in the process for crosslinking the (A) ethylene-based polymer, etc., such as melt kneading, the suitable amount of the (C) crosslinking agent is not the amount of the (C) crosslinking agent remaining in the thermoplastic elastomer composition of the present invention, but is generally specified by the amount of the (C) crosslinking agent before melt kneading the (A) ethylene-based polymer and the (B) propylene-based polymer in the presence of the (C) crosslinking agent. The amount of the (C) crosslinking agent before melt kneading is preferably 0.001 part by mass or more and 3.0 parts by mass or less, more preferably 0.01 part by mass or more and 2.0 parts by mass or less, and still more preferably 0.1 part by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the total amount of the (A) ethylene-based polymer and the (B) propylene-based polymer. When using a crosslinking aid together with the (C) crosslinking agent, the amount of the crosslinking aid before melt kneading is preferably 0.01 part by mass or more and 10 parts by mass or less, more preferably 0.05 part by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the total amount of the (A) ethylene-based polymer and the (B) propylene-based polymer.

[0053] (D) Mineral oil The thermoplastic elastomer composition of the present invention may contain (D) mineral oil. (D) The mineral oil may be mixed with the (A) ethylene-based polymer, that is, the (A) ethylene-based polymer may be extended with the (D) mineral oil. Examples of the (D) mineral oil preferably used as a softening agent in this embodiment include high-boiling fractions of petroleum such as aromatic mineral oil, naphthenic mineral oil, and paraffinic mineral oil (average molecular weight is 300 to 1500, pour point is 0 °C or lower). Among them, paraffinic mineral oil is preferred.

[0054] It is desirable to add the (D) mineral oil as an extender oil to the (A) ethylene-based polymer, particularly preferably the (A2) ethylene·α-olefin·non-conjugated diene copolymer. The addition method may be a known method. For example, (1) a method of mechanically kneading both using a kneading device such as a roll or a Banbury mixer, (2) a method of adding the component (D) to a solution of the component (A) produced in a solution state and then removing the solvent by a method such as steam stripping.

[0055] When the (D) mineral oil is blended as an extender oil for the (A) ethylene-based polymer, the Mooney viscosity (ML 1+4 100 °C) of the composition (oil-extended polymer) composed of the (D) mineral oil and the (A) ethylene-based polymer is preferably 5 or more and 300 or less, more preferably 10 or more and 250 or less, and even more preferably 40 or more and 200 or less. The Mooney viscosity (ML 1+4 100 °C) is measured according to JIS K6300. From the viewpoint of achieving the above Mooney viscosity, etc., the addition amount of the (D) mineral oil is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and even more preferably 40 to 60 parts by mass, with the total amount of the (A) ethylene-based polymer and the (D) mineral oil being 100 parts by mass.

[0056] Other components In addition to the essential components, the (A) ethylene-based polymer and the (B) propylene-based polymer (and the (C) crosslinking agent and / or the (D) mineral oil if present), the thermoplastic elastomer composition of the present invention may contain various additives. Examples of additives include polymers or oligomers other than the above components (A) and (B), plasticizers other than (D) mineral oil, inorganic fillers (such as talc, calcium carbonate, calcined kaolin, glass fiber, hollow glass spheres, silica, metal soaps, titanium dioxide, mica, potassium titanate fibers, etc.), organic fillers (such as fibers, wood powder, cellulose powder, carbon fiber, carbon black, etc.), lubricants (such as fatty acid amides, silicone oil, silicone gum, etc.), antioxidants (such as phenolic, sulfur-based, phosphorus-based, lactone-based, vitamin-based, etc.), weather stabilizers, ultraviolet absorbers (such as benzotriazole-based, triazine-based, anilide-based, benzophenone-based, etc.), heat stabilizers, light stabilizers (such as hindered amine-based, benzoate-based, etc.), pigments (such as inorganic pigments, organic pigments, pigment dispersants, etc.), nucleating agents, foaming agents, foaming nucleating agents, plasticizers, flame retardants, high-brightness agents, antibacterial agents, light diffusing agents, adsorbents (such as metal oxides (such as zinc oxide, magnesium oxide, etc.), wetting dispersants, VOC / odor stripping agents, water storage agents (such as aqueous media containing amphiphilic polymers, etc.), abrasion resistance improvers, metal chlorides (such as iron chloride, calcium chloride, etc.), hydrotalcite, aluminates, etc.). These additives may be used alone or in combination of two or more.

[0057] Examples of resins other than components (A) and (B) include olefin resins (excluding those corresponding to component (A) and component (B)), olefin elastomers (excluding those corresponding to component (A) and component (B)), hydrogenated products of block copolymers containing polymer blocks of monovinyl-substituted aromatic hydrocarbon compounds and polymer blocks of conjugated diene compounds, polyphenylene ether resins, polyamide resins, polyester resins, polyoxymethylene resins, polymethyl methacrylate resins, and the like.

[0058] Thermoplastic elastomer composition Preferably, the thermoplastic elastomer composition of the present invention contains 30 to 80 parts by mass of the (A) ethylene-based polymer and 20 to 70 parts by mass of the (B) propylene-based polymer, with the total amount of the (A) ethylene-based polymer and the (B) propylene-based polymer being 100 parts by mass. The content of the (A) ethylene polymer is more preferably from 40 to 75 mass %, particularly preferably from 50 to 70 mass %. The content of the (B) propylene-based polymer is more preferably from 25 to 60 mass %, particularly preferably from 30 to 50 mass %.

[0059] The thermoplastic elastomer composition of the present invention is subjected to a shear rate of 12 sec at a temperature of 220°C. -1 The melt viscosity measured is 2500 Pa sec or less. When the thermoplastic elastomer composition of the present invention has a melt viscosity of 2,500 Pa sec or less, it has high fluidity and excellent moldability when molded by injection molding or the like, and also has good appearance of the molded product, such as surface smoothness, and excellent bondability to other members. The melt viscosity can be measured by melting the thermoplastic elastomer composition at a predetermined temperature and measuring the melt viscosity at a predetermined shear rate according to a method known in the technical field. More specifically, the melt viscosity can be measured by, for example, the method described in the examples of the present application.

[0060] The melt viscosity can be appropriately increased or decreased by adjusting the content and melt flow rate of the (B) propylene-based polymer used in the thermoplastic elastomer composition, the proportion and particle size of the island phases in the sea-island structure usually constituted by the (A) ethylene-based polymer, the gel fraction, and the like. The melt viscosity is preferably from 500 to 2500 Pa·sec, more preferably from 800 to 2300 Pa·sec, and particularly preferably from 1000 to 2000 Pa·sec.

[0061] The thermoplastic elastomer composition of the present invention has a sea-island structure. As described above, since the (A) ethylene-based polymer is a crosslinkable polymer containing 50% by mass or more of structural units derived from ethylene, the island phase of the above sea-island structure is usually mainly composed of the (A) ethylene-based polymer. Similarly, as described above, since the (B) propylene-based polymer contains 50% by mass or more of structural units derived from propylene (compared with component (A)) and is a non-crosslinkable or decomposable polymer, the sea phase of the above sea-island structure is usually mainly composed of the (B) propylene-based polymer.

[0062] The volume average particle diameter of the island phase of the above sea-island structure is 2.1 μm or more. When the volume average particle diameter of the island phase of the sea-island structure is equal to or greater than the above predetermined value, the proportion of the sea phase occupying the surface of the molded body obtained by using the thermoplastic elastomer composition of the present invention or the interface with other members increases. Therefore, the appearance of the molded body such as surface smoothness is improved, and the bonding property with other members (especially members containing a propylene-based resin) is also improved. The volume average particle diameter of the above island phase can be measured by analyzing an image of the surface or interface obtained by a scanning electron microscope according to a method known in the art. More specifically, for example, it can be measured by the method described in the examples of the present application.

[0063] The particle diameter of the island phase of the above sea-island structure can be appropriately adjusted by adjusting the melt viscosity ratio of the (A) ethylene-based polymer and the (B) propylene-based polymer. More specifically, when the viscosities of the (A) ethylene-based polymer and the (B) propylene-based polymer during melt kneading are close, the (A) ethylene-based polymer and the (B) propylene-based polymer mix well with each other. As a result, the particle diameter of the island phase becomes small. Conversely, when the difference between the viscosity of the (A) ethylene-based polymer and the viscosity of the (B) propylene-based polymer is large, the (A) ethylene-based polymer and the (B) propylene-based polymer are difficult to mix with each other. As a result, the particle diameter of the island phase becomes large. In the thermoplastic elastomer composition of the present invention, since the melt viscosity of the (A) ethylene-based polymer is usually higher than that of the (B) propylene-based polymer, in such a case, by selecting a (B) propylene-based polymer having a low melt viscosity (a large MFR), the difference between the viscosity of the (A) ethylene-based polymer and the viscosity of the (B) propylene-based polymer can be enlarged, and the particle diameter of the island phase can be made large. Using a (B) propylene-based polymer having a low melt viscosity (a large MFR) is also preferable from the viewpoint of reducing the melt viscosity.

[0064] When crosslinking the (A) ethylene-based polymer with a peroxide or the like during melt kneading in the production of the thermoplastic elastomer composition, the melt viscosity of the (A) ethylene-based polymer tends to increase due to crosslinking, and the melt viscosity of the (B) propylene-based polymer tends to decrease due to chain scission by the peroxide or the like. Therefore, in order to adjust the particle diameter of the island phase of the sea-island structure to a desired value, it is preferable to set the melt viscosities of the (A) ethylene-based polymer and the (B) propylene-based polymer in consideration of the above tendency.

[0065] Also, the particle diameter of the island phase of the above sea-island structure can be appropriately adjusted by adjusting the intensity of melt kneading in the production of the thermoplastic elastomer composition. More specifically, by performing strong melt kneading, the (A) ethylene-based polymer and the (B) propylene-based polymer are well mixed with each other, and as a result, the particle diameter of the island phase becomes small. On the other hand, by performing weak melt kneading, the particle diameter of the island phase becomes large. The intensity of melt kneading can be specified by the specific energy (kWh / kg), which is calculated by dividing the power consumption (kW) due to melt kneading by the discharge amount (kg / h) of the melt-kneaded thermoplastic elastomer composition. The above specific energy is preferably 0.27 (kWh / kg) or less, and particularly preferably 0.1 or more and 0.25 (kWh / kg) or less.

[0066] The volume average particle diameter of the island phase of the above-mentioned sea-island structure is preferably 2.1 μm or more, more preferably 2.5 μm or more, and particularly preferably 3.0 μm or more. As described above, when the volume average particle diameter of the island phase of the above-mentioned sea-island structure is a predetermined value or more, the bonding property and adhesive strength with other members are improved. On the other hand, if there are particles with an excessively large particle diameter, stress may concentrate at the interface of such particles, and conversely, the adhesive strength may decrease. From this perspective, the volume average particle diameter of the island phase of the above-mentioned sea-island structure is preferably 10 μm or less, more preferably 8.0 μm or less, and particularly preferably 6.0 μm or less.

[0067] The particle size dispersion of the island phase of the above-mentioned sea-island structure is 7.0 or less. The particle size dispersion being a predetermined value or less means that the distribution of the particle size is uniform, and at this time, the possibility of the existence of particles with an excessively large particle diameter is low. Therefore, problems such as stress concentration at the interface of the particles and a decrease in adhesive strength can be effectively suppressed. The particle size dispersion D of the island phase is defined as the ratio Rv / Rn of the number average particle diameter Rn and the volume average particle diameter Rv, and can be determined by analyzing the image of the surface or interface obtained by a scanning electron microscope or the like according to a method known in the art. More specifically, for example, it can be determined by the method described in the examples of the present application.

[0068] The particle size dispersion of the island phase can be appropriately adjusted by adjusting the melt viscosity of the (B) propylene-based polymer and the conditions of melt kneading when producing the thermoplastic elastomer composition. For example, by selecting a (B) propylene-based polymer with a low melt viscosity (a large MFR) or by inputting a high specific energy during melt kneading, the particle size can be made uniform and the particle size dispersion can be made small. The particle size dispersion of the island phase of the above-mentioned sea-island structure is preferably 7.0 or less, and particularly preferably 6.5 or less. Although there is no particular lower limit for the particle size dispersion of the island phase of the above-mentioned sea-island structure, it is 1 or more by definition. When produced by ordinary processes, it is preferably 1.1 or more, more preferably 1.5 or more, and even more preferably 1.7 or more.

[0069] There are no particular restrictions on the method for producing the thermoplastic elastomer composition of the present invention. However, the raw materials (A) ethylene-based polymer and (B) propylene-based polymer, and various additives as desired can be kneaded by a conventional method using an ordinary extruder, Banbury mixer, roll, Brabender plastograph, kneader Brabender, etc. It is preferable to produce by melt-kneading using an extruder, particularly a twin-screw extruder.

[0070] In the production of the thermoplastic elastomer composition of the present invention, crosslinking may or may not be performed. From the viewpoints of controlling the sea-island structure, melt viscosity, etc., it is preferable to perform crosslinking. In a preferred production method when performing crosslinking, it is preferable to carry out a step of melt-kneading (A) an ethylene-based polymer and (B) a propylene-based polymer in the presence of (C) a crosslinking agent. At this time, the Mooney viscosity (ML 1+4 at 100 °C) of the (A) ethylene-based polymer is 40 or more, and the melt flow rate of the (B) propylene-based polymer measured under the conditions of a temperature of 230 °C and a load of 21.18 N is preferably 1.0 to 200 g / 10 min. When the (A) ethylene-based polymer is oil-extended with (D) mineral oil, it is preferable to carry out a step of melt-kneading an oil-extended polymer composed of (D) mineral oil and (A) ethylene-based polymer and (B) propylene-based polymer in the presence of (C) a crosslinking agent. The Mooney viscosity (ML 1+4 at 100 °C) of the oil-extended polymer is 40 or more, and the melt flow rate of the (B) propylene-based polymer measured under the conditions of a temperature of 230 °C and a load of 21.18 N is preferably 1.0 to 200 g / 10 min. By using (A) an ethylene-based polymer or an oil-extended polymer and (B) a propylene-based polymer that satisfy such conditions, the thermoplastic elastomer composition of the present invention in which the island phase has a specific volume-average particle diameter and particle diameter dispersion can be efficiently or easily produced. From the viewpoint of more efficiently or easily producing the thermoplastic elastomer composition of the present invention, the specific energy defined by the power consumption (kW) / discharge amount (kg / h) by melt kneading in the above melt kneading step is preferably 0.27 (kWh / kg) or less. The above production method can be suitably used for producing the thermoplastic elastomer composition of the present invention, but is also suitable for producing other thermoplastic elastomer compositions.

[0071] The thermoplastic elastomer composition of the present invention is used in various applications, and is particularly preferably used to constitute various members produced by injection molding or extrusion molding, a part or all of a product. In addition, when the thermoplastic elastomer composition of the present invention is used, an extruded molded body or an injection molded body having good surface smoothness can be obtained, so it can be particularly preferably used in applications where a smooth molded product appearance is required. The surface smoothness can be evaluated, for example, by measuring the ten-point average roughness of the surface of the molded body. The ten-point average roughness of the surface of the extruded molded body and the injection molded body of the present embodiment is preferably 15 μm or less, and particularly preferably 10 μm or less. Since the ten-point average roughness of the surface is generally preferably smaller, there is no particular lower limit, but when producing a thermoplastic elastomer composition at a practical cost and further producing a molded product, it usually becomes 1.0 μm or more in many cases.

[0072] Furthermore, the thermoplastic elastomer composition of the present invention is excellent in the bonding property with other members, particularly members made of a thermoplastic elastomer composition using a propylene-based polymer in the sea phase, so it can be particularly preferably used in producing a composite molded product with such members.

[0073] More specifically, preferred applications of the thermoplastic elastomer composition of the present invention include various interior and exterior automotive parts such as glass run channels, weather strips, door grommets, instrument panels, glove boxes, trims, housings, pillars, bumpers, fenders, back doors, etc., as well as various parts of household electrical appliances, various parts of housing equipment, various industrial parts, various building materials parts, etc., but are not limited thereto.

[0074] The injection molded article which is a preferred embodiment of the present invention can be produced by using the thermoplastic elastomer composition of the present invention, for example, by an ordinary injection molding method, or, if necessary, by various molding methods such as gas injection molding method, injection compression molding method, short shot foam molding method, etc. There are no particular restrictions on the molding conditions in the above injection molding, but generally it can be carried out at a molding temperature of 100 to 300°C, preferably 180 to 280°C, an injection pressure of 5 to 100 Mpa, preferably 10 to 80 Mpa, and a mold temperature of 20 to 80°C, preferably 20 to 60°C.

[0075] The injection molded article which is a preferred embodiment of the present invention may utilize its excellent bonding property to bond with other members to form a composite molded article. As the other member at that time, a molded article containing a thermoplastic elastomer composition of the same kind as the present invention, particularly a molded article containing a thermoplastic elastomer composition in which the sea phase of the sea-island structure is composed of a propylene-based polymer, is preferably used, and at this time, more excellent bonding property can be realized. The bonding strength with other members in this embodiment is preferably 3.5 MPa or more, more preferably 3.8 MPa or more, and particularly preferably 4.0 MPa or more. The higher the bonding strength with other members, the more preferable it is. In particular, there is no upper limit, but when producing a composite molded product at a practical cost, it usually becomes 6.0 MPa or less in many cases. In manufacturing the composite molded body of the present embodiment, it is preferable to place another member such as an extruded molded body in a mold, and then inject-mold the thermoplastic elastomer composition of the present invention into the mold to join it to the other member to manufacture a composite molded body. For example, by placing the main body portion (linear portion) of a glass run channel as the extruded molded body in an injection mold, and then injection-molding the thermoplastic elastomer composition of the present invention to form a corner portion joined to the main body portion, a glass run channel excellent in appearance, joining strength between the main body portion and the corner portion, etc. can be manufactured.

Examples

[0076] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0077] The physical properties and characteristics in the examples / comparative examples were evaluated by the following methods. (1) Mooney viscosity (ML 1+4 100 °C) (A) The Mooney viscosity of the ethylene-based polymer (when the (A) ethylene-based polymer is oil-extended with (D) mineral oil, the oil-extended polymer composed of the (A) ethylene-based polymer and (D) mineral oil) was measured at a temperature of 100 °C in accordance with JIS K6300.

[0078] (2) Melt flow rate (MFR, unit: g / 10 min) (A) The MFR of the ethylene-based polymer was measured in accordance with JIS K7210 under the conditions of a temperature of 190 °C and a load of 21.18 N. (B) The MFR of the propylene-based polymer was measured in accordance with JIS K7210 under the conditions of a temperature of 230 °C and a load of 21.18 N.

[0079] (3) Composition of ethylene-propylene-5-ethylidene-2-norbornene copolymer ((A) ethylene-based polymer) Measurement was carried out by infrared spectroscopy (IR method). Specifically, an ethylene-propylene-5-ethylidene-2-norbornene copolymer was formed into a film with a thickness of about 0.5 mm, and then, using an infrared spectrophotometer, the peak (1688 cm -1 of the absorption peak) intensity derived from 5-ethylidene-2-norbornene of the film was measured to calculate the content of the structural unit derived from 5-ethylidene-2-norbornene in the copolymer. Next, a new ethylene-propylene-5-ethylidene-2-norbornene copolymer was formed into a film with a thickness of about 0.1 mm, and the infrared absorption spectrum of the film was measured using an infrared spectrophotometer. According to the method described in the literature (Characterization of Polyethylene by Infrared Absorption Spectrum, written by Takayama, Usami, etc. or Die Makromolekulare Chemie, 177, 461 (1976), written by Mc Rae, M.A., MadamS, W.F., etc.), the content of the structural unit derived from ethylene and the content of the structural unit derived from propylene were calculated.

[0080] (4)(B) Intrinsic viscosity ([η cxis , unit: dl / g) of the xylene-insoluble part of the propylene-based polymer (B) After completely dissolving about 5 g of the sample of the propylene-based polymer in 500 ml of boiling xylene, the xylene solution was gradually cooled to 20 °C and adjusted for 4 hours or more at 20 °C, and then, the precipitate and the solution were filtered off. The precipitate was taken as the CXIS part. Using an Ubbelohde viscometer, the reduced viscosity was measured in tetralin at 135 °C, and from the obtained reduced viscosity, the intrinsic viscosity was determined by the extrapolation method according to the calculation method described on page 491 of "Polymer Solutions, Polymer Experimental Science 11" (published by Kyoritsu Shuppan Co., Ltd. in 1982).

[0081] (5) Melt viscosity of the thermoplastic elastomer composition Using a capillary rheometer (Capilograph 1C manufactured by Toyo Seiki Seisaku-sho, Ltd.), at a temperature of 220 °C and a shear rate of 12.16 sec -1Under the conditions, a molten thermoplastic elastomer composition was extruded from an orifice with a diameter of 1 mm and a length of 40 mm, and the melt viscosity of the thermoplastic elastomer composition was measured.

[0082] (6) Volume average particle diameter and particle size dispersion of the domain (island phase) Images for analysis were obtained using a scanning electron microscope (SEM). For sample preparation, pellets of the thermoplastic elastomer composition produced in the examples and comparative examples described below were cross-sectionally exposed with a cryomicrotome, and then RuO4 staining was performed for 90 minutes using a 1% ruthenium tetroxide (RuO4) aqueous solution. After that, an ultra-thin section with a thickness of about 150 nm was obtained with a cryomicrotome and supported on a Cu mesh to obtain an observation sample. The SEM used was HITACHI SU8020 manufactured by Hitachi High-Technologies Corporation, with an acceleration voltage of 5 kV, and the imaging mode was a reflected electron image by YAG-BSE. Each image was taken at 1280×960 pixels, and a total of 36 images, 6 vertical and 6 horizontal, with a 15% overlap between adjacent images were continuously obtained by using the automatic imaging function of the ZigZag function of the same electron microscope. The obtained images were integrated into one image using the tiling function of "ImagePro10" v10.0.3 manufactured by Nippon Roper Co., Ltd. After cutting out the central vertical 6400×horizontal 4800 image (field size of about 126 μm×about 95 μm) from the integrated image, image analysis was performed under the following conditions, and the diameter R, area S, and perimeter P of the particles were calculated for each domain. (i) Brightness of the particles: bright (ii) Binarization method: Extract the domain as the bright part, the PP part and others as the dark part using the smart extraction function. (iii) Particle segmentation: Watershed method Size 6 From the obtained values, the diameter, area, and perimeter were calculated, and with the number of rubber particles as n, the number average particle diameter Rn, volume average particle diameter Rv, and particle size dispersion D were calculated. Rn = (ΣRi) / n Rv = Σ(Ri 4 / Ri 3 ) D = Rv / Rn

[0083] (7) Ten-point average roughness i) Preparation of test piece (extruded body) Using a UNION PLASTICS USV25mmΦ extruder, the thermoplastic elastomer compositions of the examples and comparative examples were extruded under the conditions of a cylinder temperature of 200°C, a full-flight type screw, and a screw rotation speed of 40 rpm to obtain an extruded body (width 90 mm, thickness 1 mm). ii) Evaluation of ten-point average roughness In accordance with JIS B0601, using a surface roughness profiler "Surfcom 480A" manufactured by Tokyo Seimitsu Co., Ltd., the ten-point average roughness of the surface of the extruded body produced in i) above was measured.

[0084] (8) Evaluation of adhesiveness to thermoplastic elastomer molded body The thermoplastic elastomer molded body (Y) obtained in [Reference Example 1] described later was used as the adherend. First, the thermoplastic elastomer molded body (Y) was attached to an injection mold with double-sided tape. Then, using a Toshiba Machine Co., Ltd. IS100EN-3A injection molding machine, the thermoplastic elastomer compositions produced in each example / comparative example were injection molded under the conditions of a molding temperature of 250°C and a mold temperature of 50°C to obtain a composite molded body (Z1) in which the above thermoplastic elastomer molded body (Y) and the injection molded body portion made of the thermoplastic elastomer composition obtained in each example were melt-bonded. The molded body (Z1) was punched out with a JIS No. 3 dumbbell so that the melt-bonded surface was perpendicular to the long side direction of the test piece to prepare a test piece. For the above test piece, a tensile test was performed under the condition of a tensile speed of 200 mm / min to evaluate the adhesive strength. [Reference Example 1] (Preparation of thermoplastic elastomer molded body (Y)) Using a Toshiba Machine Co., Ltd. IS100EN-3A injection molding machine, the thermoplastic elastomer "Santoprene 121-73W175" manufactured by ExxonMobil was injection molded under the conditions of a molding temperature of 220 °C, a mold temperature of 50 °C, an injection time of 10 seconds, and a cooling time of 30 seconds to obtain an injection molded product (150 mm long, 90 mm wide, and 2.0 mm thick). Next, the injection molded product was cut with a cutter to a size of 30 mm long, 90 mm wide, and 2.0 mm thick, and this was used as the thermoplastic elastomer molded product (Y).

[0085] (9) Specific energy In the production of the thermoplastic elastomer, the energy required for melt kneading was determined from the power consumption (kW) of the twin-screw kneading extruder and divided by the discharge rate (kg / h) of the twin-screw kneading extruder to obtain the specific energy (kWh / kg).

[0086] Details of the materials used in the examples / comparative examples are as follows.

[0087] Oil-extended ethylene random copolymer (composition consisting of component (A2) and component (D)) (A2-i)+(D-i) (A2-i) Ethylene-propylene-5-ethylidene-2-norbornene copolymer 100 parts by mass, to which 100 parts by mass of (D-i) paraffinic mineral oil (trade name "PW-380" manufactured by Idemitsu Kosan Co., Ltd.) is added) (A2-i)+(D-i) Mooney viscosity (ML 1+4 100 °C) = 53, (A2-i) composition Content of structural units derived from ethylene = 62.0% by mass Content of structural units derived from propylene = 28.1% by mass Content of structural units derived from 5-ethylidene-2-norbornene = 9.9% by mass

[0088] Propylene polymer (component (B)) (B-i) Propylene homopolymer (h-PP) MFR (230 °C) = 0.5 g / 10 min, intrinsic viscosity of xylene-insoluble part [η cxis = 3.0 dl / g (B-ii) Homopolymer of propylene (h-PP) MFR (230 °C) = 13 g / 10 min, intrinsic viscosity of xylene-insoluble part [η cxis = 1.5 dl / g (B-iii) Homopolymer of propylene (h-PP) MFR (230 °C) = 100 g / 10 min, intrinsic viscosity of xylene-insoluble part [η cxis = 0.9 dl / g

[0089] Crosslinking agent + mineral oil (composition consisting of component (C) and component (D)) (C-i) + (D-ii): Product name "APO-10DL" manufactured by Chemische Fabrik Stockhausen GmbH APO-10DL is a composition consisting of 10% by mass of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (hereinafter referred to as (C-i)) and 90% by mass of paraffinic mineral oil (product name "PW-100" manufactured by Idemitsu Kosan Co., Ltd.; hereinafter referred to as (D-ii)) (however, the total amount of (C-i) and (D-ii) is 100% by mass).

[0090] Fatty acid amide: Product name "Neutron-S" (erucic acid amide) manufactured by Nippon Seika Chemical Co., Ltd. Crosslinking aid: Product name "Sumifine BM" (N,N'-m-phenylenebismaleimide) manufactured by Sumitomo Chemical Co., Ltd. Antioxidant: Product name "Irganox 1010" manufactured by BASF Japan Ltd.

[0091] <Example 1> 75.0 parts by mass of an oil-extended ethylene random copolymer ((A2-i) + (D-i)), 25.0 parts by mass of a homopolymer of propylene (B-ii), 3.2 parts by mass of a crosslinking agent (C-i + D-ii), 0.125 parts by mass of a fatty acid amide, 0.1 part by mass of a crosslinking aid (Sumifine BM), and 0.200 parts by mass of an antioxidant were melt-kneaded at 200 °C ± 20 °C for 40 seconds ± 20 seconds in a screw pattern A using a twin-screw kneading extruder (TEX-44HCT) manufactured by Japan Steel Works, Ltd. to produce a thermoplastic elastomer composition. The obtained thermoplastic elastomer composition was extrusion-molded by the method of (7) above and injection-molded by the method of (8) above to obtain a molded article. Table 1 shows the physical property measurement results of the molded article and the evaluation results of the adhesiveness to the thermoplastic elastomer molded article.

[0092] <Examples 2 to 5, Comparative Examples 1 to 3> A thermoplastic elastomer composition was produced and evaluated in the same manner as in Example 1, except that the blending of raw materials and the specific energy were changed as shown in Table 1. The results are shown in Table 1.

[0093]

Table 1

Industrial Applicability

[0094] The thermoplastic elastomer composition of the present invention can produce a molded article having good appearance of the molded article such as surface smoothness and excellent joinability with other members, and is particularly suitable for injection molding. Therefore, it is suitable for various automotive interior and exterior parts such as glass run channels, weather strips, door grommets, instrument panels, glove boxes, trims, housings, pillars, bumpers, fenders, back doors, etc., as well as various parts of household electrical appliances, various parts of housing equipment, various industrial parts, various building materials parts, etc. It has high applicability in various fields of industries such as the transportation machinery industry, the electric and electronic industry, and the construction industry.

Claims

1. A thermoplastic elastomer composition containing (A) an ethylene-based polymer and (B) a propylene-based polymer, Temperature 220°C, shear rate 12 sec －１ the melt viscosity of the thermoplastic elastomer composition at that time is 2500 Pa·sec or less, wherein the melt flow rate of (B) the propylene-based polymer measured under the conditions of a temperature of 230°C and a load of 21.18 N is 10 g / 10 min or more, and the thermoplastic elastomer composition has a sea-island structure, the volume average particle diameter of the island phase is 2.1 μm or more, and the particle size dispersion D is 7.0 or less.

2. The thermoplastic elastomer composition according to claim 1, further containing (D) a mineral oil, wherein the (A) ethylene-based polymer is oil-extended with the (D) mineral oil.

3. The Mooney viscosity (ML 1+4 at 100 °C) of the ethylene polymer is 40 or more, and the thermoplastic elastomer composition according to claim 1.

4. The Mooney viscosity (ML 1+4 100 °C) of the oil-extended polymer composed of (A) an ethylene-based polymer and (D) a mineral oil is 40 or more, and the thermoplastic elastomer composition according to claim 2.

5. A method for producing a thermoplastic elastomer composition, including a step of melt-kneading (A) an ethylene-based polymer and (B) a propylene-based polymer in the presence of (C) a crosslinking agent, The Mooney viscosity (ML 1+4 at 100 °C) of the ethylene-based polymer is 40 or more, and (B) the melt flow rate of the propylene-based polymer measured under the conditions of a temperature of 230 °C and a load of 21.18 N is 10 to 200 g / 10 min. The above production method.

6. The method for producing a thermoplastic elastomer composition according to claim 5, wherein the specific energy defined by the power consumption (kW) / discharge amount (kg / h) by melt-kneading in the above step is 0.27 (kWh / kg) or less.

7. A method for producing a thermoplastic elastomer composition, including a step of melt-kneading an oil-extended polymer and (B) a propylene-based polymer in the presence of (C) a crosslinking agent, wherein the oil-extended polymer consists of (A) an ethylene-based polymer and (D) a mineral oil. The Mooney viscosity (ML 1+4 at 100 °C) of the oil-extended polymer is 40 or more, and (B) the melt flow rate of the propylene-based polymer measured under the conditions of a temperature of 230 °C and a load of 21.18 N is 10 to 200 g / 10 min. The above production method.

8. The method for producing a thermoplastic elastomer composition according to claim 7, wherein the specific energy defined by the power consumption (kW) / discharge amount (kg / h) by melt-kneading in the above step is 0.27 (kWh / kg) or less.

9. The method for producing a thermoplastic elastomer composition according to claim 5 or 6, wherein the thermoplastic elastomer composition according to claim 1 or 3 is produced.

10. The method for producing a thermoplastic elastomer composition according to claim 7 or 8, wherein the thermoplastic elastomer composition according to claim 2 or 4 is produced.

11. An injection molded article comprising the thermoplastic elastomer composition according to any one of claims 1 to 4.

12. A composite molded article formed by joining the injection molded article according to claim 11 and an extrusion molded article comprising a thermoplastic elastomer composition.

13. The composite molded article according to claim 12, which is a glass run channel.

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