WO2020045082A1

WO2020045082A1 - Thermoplastic elastomer composition and production method therefor

Info

Publication number: WO2020045082A1
Application number: PCT/JP2019/031875
Authority: WO
Inventors: 亘佑中村; 雄志熊谷; 勝長谷川; 哲央野口
Original assignee: デンカ株式会社
Priority date: 2018-08-30
Filing date: 2019-08-13
Publication date: 2020-03-05
Also published as: JPWO2020045082A1; JP7348191B2

Abstract

A thermoplastic elastomer composition which comprises 50-85 mass% cross copolymer (A) and 15-50 mass% polyethylene-based resin (B) and which has an MFR (230°C, 10-kg load) of 0.3-10 g/10 min and a gel content of 1.0 mass% or higher.

Description

Thermoplastic elastomer composition and method for producing the same

The present invention relates to a thermoplastic elastomer composition having excellent heat resistance, oil resistance, and scratch resistance, and a molded article, a sheet, and a skin material using the same, and a method for producing the same.

表 Skin materials covering the surface of various hard machines such as passenger cars and various automobiles, furniture and indoor interiors, and robots are required to have various functions in addition to various levels of softness. For example, as interior skin materials for automobiles, heat resistance, weather resistance, cold resistance, creasing retention including heat history during molding, scratch resistance to human contact (scratch wear resistance), accompanying humans Oil resistance and chemical resistance to chemical substances are required. Conventionally, in such a field, a skin material sheet made of soft vinyl chloride (soft PVC) to which a plasticizer is added has been used. Soft PVC has excellent softness, oil resistance, and scratch resistance, and is a material that is advantageous in cost. However, soft PVC contains problems of management during incineration, that is, volatile organic compounds (VOCs) due to plasticizers contained in large quantities in recent years, concerns that some plasticizers may become environmental hormones, and heavy metal stabilizers. Therefore, there is a demand for materials having better environmental properties. Therefore, skin material sheets made of TPO (thermoplastic olefin resin) or TPS (thermoplastic styrene resin) have been receiving attention. TPO and TPS are characterized by heat resistance, softness, recyclability, and environmental friendliness, and have been widely used. These materials are compounds composed of a soft component and a heat-resistant component, but have the problem that the scratch resistance is reduced to an insufficient level by the PP (isotactic polypropylene) component used as the heat-resistant component. I have. Further, the crosslinked ethylene-propylene rubber or the crosslinked or non-crosslinked styrene-based hydrogenated block copolymer used as a soft component does not have sufficient oil resistance, and may swell or deform in a severe environment. Even if an attempt is made to improve the scratch resistance by reducing the amount of PP added, there is a problem that the heat resistance, in particular, the surface grain retention at the time of sheet molding is reduced and the grain disappears.

数多く Based on the above situation, many new thermoplastic elastomers having the required characteristics according to various applications have been proposed. For example, Patent Literatures 1 and 2 disclose a so-called “method” obtained by a method of copolymerizing a small amount of divinylbenzene with a styrene-ethylene copolymer and introducing a polystyrene chain (cross chain) via a vinyl group of the divinylbenzene unit. Cross copolymers have been proposed. The cross copolymer obtained by this method is a block copolymer having a branched structure having a styrene-ethylene copolymer chain as a soft segment and polystyrene as a hard segment.

JP 2009-102515 A International Publication No. 2007/139116 International Publication No. 2009/128444 JP 2010-24215 A

Cloth copolymers are thermoplastic elastomers that have excellent properties such as scratch resistance, softness, transparency, and moldability, but depending on the application, heat resistance and oil resistance may be insufficient. However, there is a problem that it is difficult to improve heat resistance and oil resistance while maintaining such characteristics. In order to cope with such a problem, if PP is added to increase the heat resistance, the abrasion resistance with scratches is reduced as in the case of TPO and TPS. Therefore, the addition of PPE (polyphenylene ether) resin (Patent Document 3) and the addition of TPEE (Polyester soft resin) (Patent Document 4) improve the heat resistance. The heat resistance of the styrene-ethylene cross copolymer sheet can be improved by electron beam crosslinking. Patent Literature 1 describes in particular a tape base material, an electric wire covering material, and a foamed material using an electron beam crosslinked body of a cross copolymer. For example, Patent Document 2 describes a composition obtained by dynamically cross-linking a cross-copolymer with another polymer, particularly a crystalline polypropylene.

However, the thermoplastic elastomer composition using the above-mentioned cross-copolymer according to the conventional technique still cannot be said to have sufficient heat resistance and oil resistance, and does not have sufficient scratch resistance. In particular, interior skin materials for automobiles and the like are required to have high heat resistance, oil resistance, and scratch resistance, and are also required to have high-temperature oil resistance, so that a higher-performance thermoplastic elastomer composition has been required. .

The present invention can provide a thermoplastic elastomer composition having excellent heat resistance, oil resistance, and scratch resistance, and a molded article, a sheet, and a skin material using the same.

That is, the following can be provided in the embodiment of the present invention.

[1]
A cross-copolymer (A) containing 50 to 85% by mass and a polyethylene resin (B) 15 to 50% by mass,
MFR (230 ° C., 10 kg load) is 0.3 g / 10 min or more and 10 g / 10 min or less, and contains a gel content of 1.0 mass% or more;
Thermoplastic elastomer composition.

[2]
The thermoplastic elastomer composition according to [1], wherein the storage elastic modulus E ′ measured at 150 ° C., a frequency of 1 Hz, and a temperature rise of 4 ° C./min is in a range of 1 × 10 ⁵ to 5 × 10 ⁶ Pa. .

[3]
Under the conditions of 150 ° C., a frequency of 1 Hz, and a temperature rise of 4 ° C./min, the storage elastic modulus E ′ can be measured at 150 ° C. and 190 ° C., and the ratio of the storage elastic modulus E ′ between 190 ° C. and 150 ° C. (E ′ ( 190) / E ′ (150)) is 0.3 or more, the thermoplastic elastomer composition according to [1] or [2].

[4]
The cross copolymer (A) has a structure in which an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. The thermoplastic elastomer composition according to any one of [1] to [3], which is a copolymer satisfying at least one of the following conditions (1) to (3).
(1) The content of the aromatic vinyl compound monomer unit of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the content of the aromatic polyene monomer unit is 0.01 mol% or more. 0.5 mol% or less, the balance being the content of olefin monomer units.
(2) The olefin-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw / Mn) of 1.8 or more and 6 or less.
(3) The content of the olefin-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is in the range of 60 to 95% by mass.

[5]
The cross copolymer (A) has a structure in which an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. The thermoplastic elastomer composition according to any one of [1] to [4], which is a copolymer satisfying at least one of the following conditions (1) to (3).
(1) The content of the aromatic vinyl compound monomer unit of the ethylene-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the content of the aromatic polyene monomer unit is 0.01 mol% or more. 0.5 mol% or less, with the balance being the ethylene monomer unit content.
(2) The ethylene-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw / Mn) of 1.8 or more and 6 or less.
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is in the range of 70 to 95% by mass.

[6]
The cross copolymer (A) is composed of 70 to 95% by mass of an olefin-aromatic vinyl-aromatic polyene copolymer having an aromatic vinyl monomer unit content of 10 to 30% by mole, and aromatic vinyl monomer. 5 to 30% by mass of an aromatic vinyl polymer comprising monomer units, and the olefin-aromatic vinyl-aromatic polyene copolymer and the aromatic vinyl polymer cannot be substantially separated by solvent separation. The thermoplastic elastomer composition according to any one of [1] to [5].

[7]
The thermoplastic elastomer composition according to any one of [1] to [6], wherein the polyethylene resin (B) is high density polyethylene (HDPE).

[8]
A thermoplastic elastomer composition further comprising 1 to 40 parts by mass of a polypropylene resin (C) based on 100 parts by mass of the thermoplastic elastomer composition according to any one of [1] to [7].

[9]
Further, 1 to 50 parts by mass of a plasticizer (D) and / or 1 to 25 parts by mass of a styrene-based thermoplastic elastomer (E) based on 100 parts by mass of the thermoplastic elastomer composition according to [1] or [8]. A thermoplastic elastomer composition blended by mass.

[10]
A molded article comprising the thermoplastic elastomer composition according to any one of [1] to [9].

[11]
The molded article according to [10], which is a sheet.

[12]
A multilayer sheet including the sheet according to [11].

[13]
The molded article according to [10], wherein a change in specular gloss measured at an incident angle of 60 ° after exposure to a 110 ° C environment for 24 hours is 1.0% or less.

[14]
A skin material comprising the sheet according to [11] or the multilayer sheet according to [12].

[15]
An automobile interior member including the skin material according to [14].

[16]
A method for producing a thermoplastic elastomer composition, comprising a step of mixing a cross-copolymer (A), a polyethylene-based resin (B), and a crosslinking agent under shear and crosslinking.

[17]
A step of synthesizing an olefin, an aromatic vinyl compound, and an aromatic polyene monomer from each monomer using a coordination polymerization catalyst to synthesize an olefin-aromatic vinyl compound-aromatic polyene copolymer;
An aromatic vinyl compound monomer and an anionic polymerization initiator are added to the obtained olefin-aromatic vinyl compound-aromatic polyene copolymer, and anion polymerization is performed to obtain the cross copolymer (A). The production method according to [16], further comprising:

[18]
A step of blending and kneading the polypropylene-based resin (C), the plasticizer (D), and / or the styrene-based thermoplastic elastomer (E) with the thermoplastic elastomer composition obtained in [16] or [17]. A method for producing a thermoplastic elastomer composition, further comprising:

According to the present invention, it is possible to provide a thermoplastic elastomer composition having excellent heat resistance, oil resistance, and scratch resistance, and a molded article, a sheet, and a skin material using the same.

It is a graph which shows the storage elastic modulus of the thermoplastic elastomer composition which concerns on an Example and a comparative example.

Hereinafter, the thermoplastic elastomer composition of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within a range that does not impair the effects of the present invention. In the present specification and claims, a numerical range includes a lower limit value and an upper limit value unless otherwise specified.

The thermoplastic elastomer composition contains the cross copolymer (A) and the polyethylene resin (B).

[Cross copolymer (A)]
As the cross-copolymer (A), any one can be used as long as the polymer main chain and another polymer chain are cross-linked. In a preferred embodiment, the cross copolymer (A) may have a structure in which an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded. In a further preferred embodiment, the cross-copolymer (A) is composed of an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain via an aromatic polyene monomer unit. May have a combined structure.

In a preferred embodiment, the cross copolymer (A) may be a copolymer satisfying at least one, more preferably at least two, and more preferably all of the following conditions (1) to (3).
(1) The content of the aromatic vinyl compound monomer unit of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, more preferably 12 to 28 mol%, and further preferably 15 to 25 mol. %, The content of the aromatic polyene monomer unit is 0.01 mol% or more and 0.5 mol% or less, more preferably 0.01 mol% or more and 0.4 mol% or less, further preferably 0.02 mol% or more. 0.1 mol% or less, the balance being the content of olefin monomer units.
(2) The weight average molecular weight of the olefin-aromatic vinyl compound-aromatic polyene copolymer is from 50,000 to 300,000, and the molecular weight distribution (Mw / Mn) is from 1.8 to 6, more preferably 1.8 or more. 5 or less, more preferably 1.8 or more and 4 or less.
(3) The content of the olefin-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is 60 to 95% by mass, more preferably 65 to 90% by mass, and further preferably 70 to 95% by mass. In the range.

Examples of the olefin monomer unit include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, vinylcyclohexane, and cyclic olefins, ie, cyclopentene. Α-olefins and cyclic olefins, for example, and norbornene. Preferably, the olefin may include an ethylene monomer, and most preferably is an ethylene monomer.

When an ethylene monomer unit is used, the ethylene monomer unit is preferably used alone. In addition to ethylene, a relatively small amount of an α-olefin having 3 to 20 carbon atoms is used as long as the effect of the present invention is not impaired. Α-olefin-based monomers and cyclic olefin-based monomers such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, vinylcyclohexane, and cyclic olefins such as cyclopentene and norbornene May be copolymerized.

Examples of the aromatic vinyl compound monomer unit include styrene and various substituted styrenes such as p-methylstyrene, m-methylstyrene, o-methylstyrene, ot-butylstyrene, mt-butylstyrene, and p-methylstyrene. Examples include units derived from each styrene monomer such as t-butylstyrene, p-chlorostyrene, and o-chlorostyrene. Among these, a styrene unit, a p-methylstyrene unit and a p-chlorostyrene unit are preferred, and a styrene unit is particularly preferred. One of these aromatic vinyl compound monomer units may be used alone, or two or more of them may be used in combination.

として As the aromatic polyene monomer unit, for example, an aromatic polyene having 10 to 30 carbon atoms and having a plurality of double bonds (vinyl groups) and one or more aromatic groups can be used. For example, o-divinylbenzene, p-divinylbenzene, m-divinylbenzene, 1,4-divinylnaphthalene, 3,4-divinylnaphthalene, 2,6-divinylnaphthalene, 1,2-divinyl-3,4-dimethylbenzene And units derived from aromatic polyene monomers such as 1,3-divinyl-4,5,8-tributylnaphthalene, and preferably any one of an orthodivinylbenzene unit, a paradivinylbenzene unit and a metadivinylbenzene unit. One type or a mixture of two or more types is suitably used.

The content ratio in the olefin-aromatic vinyl compound-aromatic polyene copolymer is in the range of 10 to 30 mol% of the monomer unit of the aromatic vinyl compound from the viewpoint of improving softness and scratch resistance. Is preferred. When the amount of the aromatic vinyl compound monomer unit is 10 mol% or more, sufficient softness and scratch resistance can be obtained. When the amount of the aromatic vinyl compound monomer unit is 30 mol% or less, sufficient flexibility at low temperatures is obtained, and the scratch resistance is improved.

含有 The content of the aromatic polyene monomer unit may be 0.01 to 0.5 mol%, preferably 0.02 to 0.1 mol%. When the aromatic polyene monomer unit is at least 0.01 mol%, the mechanical properties will be improved, and when it is at most 0.5 mol%, the moldability will be improved.

In the cross copolymer (A), the content ratio of the olefin-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain is preferably from the viewpoint of improvement in softness. The amount of the aromatic vinyl compound-aromatic polyene copolymer chain may be 70 to 95% by mass, and the amount of the aromatic vinyl compound polymer chain may be 5 to 30% by mass. Further, from the viewpoint of improving the physical properties of the thermoplastic elastomer composition, from 82 to 92% by mass of the olefin-aromatic vinyl compound-based copolymer, and from 8 to 18% by mass of the polymer comprising the aromatic vinyl compound monomer unit. %.

For details of the present cross-copolymer and a method for producing the same, WO2000 / 37517, WO2007 / 139116, or JP2009-120792, the entire description of which is incorporated herein by reference. It is described in the gazette.

In a preferred embodiment, the cross copolymer (A) is obtained by copolymerizing ethylene, an aromatic vinyl compound, and an aromatic polyene monomer using a coordination polymerization catalyst to form an ethylene-aromatic vinyl compound-aromatic A polyene copolymer is synthesized, and in an anion polymerization step, a polymerization method is carried out using an anion polymerization initiator in the coexistence of an ethylene-aromatic vinyl compound-aromatic polyene copolymer and an aromatic vinyl compound monomer. The obtained copolymer may further satisfy all of the following conditions (1) to (3).
(1) The content of the aromatic vinyl compound monomer unit of the ethylene-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the content of the aromatic polyene monomer unit is 0.01 mol% or more. 0.5 mol% or less, with the balance being the ethylene monomer unit content.
(2) The ethylene-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw / Mn) of 1.8 or more and 6 or less.
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is in the range of 60 to 95% by mass.

In a preferred embodiment, the olefin-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain may be bonded via an aromatic polyene monomer unit. The formation of the bond mediated by the aromatic polyene monomer unit can be proved by the following observable phenomenon. In the following description, as a preferable example, an ethylene-styrene (aromatic vinyl compound) -divinylbenzene (aromatic polyene) copolymer chain and a polystyrene (aromatic vinyl compound) chain are linked via a divinylbenzene unit. The case where they are combined is shown.

¹ H-NMR of the ethylene-styrene-divinylbenzene copolymer macromonomer obtained in the coordination polymerization step, and the cross-copolymer obtained through anionic polymerization in the presence of the copolymer and the styrene unit ( Proton NMR) is measured, and the peak intensity of the vinyl group hydrogen (proton) of both divinylbenzene units is compared using an appropriate internal standard peak (an appropriate peak derived from an ethylene-styrene-divinylbenzene copolymer). . Here, as described above, in the case of a cross copolymer having a bond in which an aromatic polyene monomer unit is interposed, the peak intensity (area) of the vinyl group hydrogen (proton) of the divinylbenzene unit is ethylene-styrene- Compared with the same peak intensity (area) of the divinylbenzene unit of the divinylbenzene copolymer macromonomer, the peak intensity is less than 50%, preferably less than 20%. This is because during the anionic polymerization (cross-forming step), the divinylbenzene unit is copolymerized simultaneously with the polymerization of the styrene unit, and the ethylene-styrene-divinylbenzene copolymer chain and the polystyrene chain are bonded via the divinylbenzene unit. Therefore, in the cross-copolymer after anionic polymerization, the peak intensity of hydrogen (proton) of the vinyl group of the divinylbenzene unit is greatly reduced. Actually, the peak of hydrogen (proton) of the vinyl group of the divinylbenzene unit has substantially disappeared in the cross copolymer after anionic polymerization. The details of the above method are described in a known document "Synthesis of a branched copolymer using an olefin-based copolymer containing a divinylbenzene unit", Toru Arai, Masaru Hasegawa, Journal of the Rubber Society of Japan, p382, vol. 82 (2009).

From another viewpoint, in the cross copolymer (A), an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. (For example, an ethylene-styrene-divinylbenzene copolymer chain and a polystyrene chain are bonded via a divinylbenzene unit) can be proved by the following observable phenomenon. That is, as described above, the cross-copolymer having a bond in which an aromatic polyene monomer unit is interposed therein contains ethylene-styrene- Divinylbenzene copolymer chains and polystyrene chains cannot be separated. Ethylene-styrene-divinylbenzene copolymer and polystyrene having the same composition as the ethylene-styrene-divinylbenzene copolymer chain contained in the ordinary cross-copolymer are subjected to Soxhlet extraction with boiling acetone to form acetone-insoluble parts. Usually, it can be separated into polystyrene as an acetone-soluble part in an ethylene-styrene-divinylbenzene copolymer. However, when the same Soxhlet extraction was performed on a cross copolymer having an aromatic polyene monomer unit interposed bond, a relatively small amount of polystyrene homogen contained in the present cross copolymer as an acetone-soluble portion was obtained. Although a polymer is obtained, the acetone-insoluble portion occupying most of the amount is shown by NMR measurement to contain both the ethylene-styrene-divinylbenzene copolymer chain and the polystyrene chain. It can be seen that it cannot be separated by Soxhlet extraction. The details of this method are also described in the above-mentioned known document "Synthesis of branched copolymers using olefin-based copolymers containing divinylbenzene units", Toru Arai, Masaru Hasegawa, Journal of the Rubber Society of Japan, p382, vol. 82 (2009).

From the above, the cross copolymer (A) according to a preferred embodiment has an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain, and is an ethylene-aromatic vinyl compound. An ethylene-aromatic vinyl compound-aromatic polyene copolymer having a structure in which an aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit It may be a copolymer in which the chain and the aromatic vinyl compound polymer chain cannot be separated substantially by solvent separation. The term "substantially" as used herein means that the present cross-copolymer may contain a relatively small amount of an aromatic vinyl compound (polystyrene) homopolymer that does not impair the effects of the present invention. I do.

(4) The weight average molecular weight Mw of the aromatic vinyl compound polymer chain contained in the cross copolymer (A) is arbitrary, but is generally in the range of 10,000 to 80,000. In the cross copolymer, the molecular weight of the aromatic vinyl compound polymer chain bonded to the main chain olefin-aromatic vinyl compound-aromatic polyene copolymer cannot be determined. The weight average molecular weight Mw of the aromatic vinyl compound polymer homopolymer contained in the copolymer in a relatively small amount is defined as the weight average molecular weight Mw of the aromatic vinyl compound polymer chain contained in the cross copolymer. I have.

When the cross copolymer (A) was subjected to ¹ H-NMR measurement, the amount of the aromatic polyene (eg, divinylbenzene) unit contained was significantly smaller than that of the aromatic vinyl compound (eg, styrene) unit. Since the position overlaps with the aromatic vinyl compound (for example, styrene) unit, the peak cannot be directly confirmed. Therefore, in the ¹ H-NMR measurement of the cross copolymer according to the preferred embodiment, the peak derived from the olefin-aromatic vinyl compound-aromatic polyene copolymer (ethylene-styrene-divinylbenzene copolymer) and the aromatic A peak derived from a vinyl compound polymer (polystyrene) was observed, and an olefin unit derived from an olefin-aromatic vinyl compound-aromatic polyene copolymer (ethylene-styrene-divinylbenzene copolymer) of a cross-copolymer was observed. Content, aromatic vinyl compound (styrene) unit content, and aromatic vinyl compound polymer (polystyrene) content. Note that, here, the olefin-aromatic vinyl compound-aromatic polyene copolymer (ethylene-styrene-divinylbenzene copolymer) may contain from 0.01 mol% to 0.5 mol% of the aromatic compound. The polyene (divinylbenzene) content is determined by including the aromatic vinyl compound (styrene) unit content in which the peak positions overlap with each other. In addition, the above-mentioned acetone-insoluble portion which occupies most of the cross-copolymer includes an ethylene-aromatic vinyl compound-aromatic polyene copolymer (ethylene-styrene-divinylbenzene copolymer) and an aromatic vinyl compound polymer ( Polystyrene), which cannot be separated by further fractionation. Therefore, in a preferred cross copolymer, the ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain have a bond (for example, ethylene-styrene-divinylbenzene copolymer). (A polymer chain and a polystyrene chain have a bond). The cross-copolymer has substantially no gel component despite the bond between the ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain. And a practical molding processability as a thermoplastic resin, that is, a specific MFR value.

The cross copolymer (A) according to a preferred embodiment comprises 70 to 95% by mass of an olefin-aromatic vinyl compound-aromatic polyene copolymer having an aromatic vinyl monomer unit content of 10 to 30 mol%. And 5 to 30% by mass of an aromatic vinyl polymer comprising an aromatic vinyl monomer unit, and the two may be substantially inseparable by solvent separation.

[Polyethylene resin (B)]
The polyethylene resin (B) in which the thermoplastic elastomer composition of the present invention can be used may be a resin containing 50% by mass or more of an ethylene monomer unit. The polyethylene resin (B) may be an ethylene homopolymer, and ethylene and another α-olefin, for example, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, or a mixture thereof. It may be a copolymer with the above mixture. The polyethylene resin (B) may be high-density polyethylene (hereinafter “HDPE”), low-density polyethylene (hereinafter “LDPE”), linear low-density polyethylene (hereinafter “LLDPE”), or a mixture thereof.

HDPE has a density of 0.940 g / cm ³ or more, preferably 0.940 to 0.970 g / cm ³ , more preferably 0.950 to 0.970 g / cm ³ . The melting point thereof is preferably 126 to 136 ° C. as measured by a DSC method (differential scanning calorimeter), the melt flow rate (MFR) is 190 ° C. specified by JIS K-6922-2: 2010, and the load is 2.16 kg. Under the measurement conditions, it is preferably 0 (substantially no flow) to 30 g / 10 min, more preferably 0.05 to 10 g / 10 min. Those having an MFR of 0.05 g / 10 min or more have excellent processability of the thermoplastic elastomer composition, and those having an MFR of 10 g / 10 min or less have high mechanical properties of the obtained thermoplastic elastomer composition. Also, a so-called ultrahigh molecular weight polyethylene having a number average molecular weight of 1,000,000 or more can be suitably used.

LDPE and LLDPE preferably have a melting point of 60 to 125 ° C. measured by a DSC method (differential scanning calorimeter), a melt flow rate (MFR) of 190 ° C. specified in JIS @ K-6922-2: 2010, and a load. Under the measurement conditions of 2.16 kg, it is preferably 0.05 to 30 g / 10 min, and more preferably 0.05 to 10 g / 10 min. If the MFR is 0.05 g / 10 min or more, the thermoplastic elastomer composition has excellent processability, and if the MFR is 30 g / 10 min or less, the obtained thermoplastic elastomer composition has high mechanical properties. LDPE is usually produced by a known high-pressure radical polymerization method, and may be produced by any of a tubular method and an autoclave method. LLDPE can be produced by coordination polymerization using a Ziegler-Natta catalyst or a metallocene catalyst, by copolymerizing ethylene and an α-olefin as a comonomer.

ＨＤ From the viewpoint of the heat resistance of the obtained thermoplastic elastomer composition, HDPE is preferred as the polyethylene resin (B) to be used.

[Thermoplastic elastomer composition]
The thermoplastic elastomer composition of the present embodiment contains 50 to 85% by mass of the cross copolymer (A) and 15 to 50% by mass of the polyethylene resin (B). If the cross copolymer (A) is less than 50% by mass, the resulting composition may have insufficient flexibility, and if it is more than 85% by mass, heat resistance and oil resistance may be insufficient.

ゲル The thermoplastic elastomer composition according to the embodiment of the present invention has a gel content of 1.0% by mass or more. In a preferred embodiment, the gel fraction can be measured in boiling xylene (140 ° C.) after 8 hours. If the gel content is less than 1.0% by mass, crosslinking is insufficient, and heat resistance and oil resistance may be insufficient. Preferably, the gel content is from 3.0% by mass to 60% by mass. If it is at most 60% by mass, thermoplasticity and moldability will be good.

The MFR (measured based on JIS K7210-1: 2014) of the thermoplastic elastomer composition according to the embodiment of the present invention is preferably 0.3 g / 10 min or more and 10 g / 10 min or less. More preferably, the storage elastic modulus E ′ measured under the conditions of 150 ° C., a frequency of 1 Hz, and a temperature rise of 4 ° C./min is in the range of 1 × 10 ⁵ to 5 × 10 ⁶ Pa, and more preferably 1 × 10 ⁵ to 2 Pa. × 10 ⁶ Pa, and the gel content after 8 hours in boiling xylene (140 ° C.) is 1.0% by mass or more. In a particularly preferred embodiment, the ratio of the storage modulus E ′ (E ′ (190) / E ′ (150)) of the thermoplastic elastomer composition at 190 ° C. and 150 ° C., respectively, may be 0.3 or more. , More preferably 0.3 or more and 1 or less.

Ａ The thermoplastic elastomer composition according to the embodiment of the present invention preferably has an A hardness (measured based on JIS K-6253-3: 2012) of 95 or less, more preferably 90 or less, and 70 or more. When the A hardness is in this range, even if a polypropylene-based resin is further compounded as shown below, it is possible to have appropriate softness as a skin material.

When the MFR (JIS # K7210: 2014) of the thermoplastic elastomer composition is less than 0.3 g / 10 minutes, there is a possibility that the moldability may be insufficient and economical efficiency may be lost during the production, and if it is higher than 10 g / 10 minutes. , Heat resistance and oil resistance may be reduced.

If the storage modulus E ′ of the thermoplastic elastomer composition measured at 150 ° C., a frequency of 1 Hz and a temperature rise of 4 ° C./min is less than 1 × 10 ⁵ , the heat resistance may be reduced. On the other hand, when it is higher than 5 × 10 ⁶ Pa, the thermoplasticity is relatively reduced, and the moldability may be deteriorated. Further, the storage elastic modulus of the thermoplastic elastomer composition according to the embodiment of the present invention can be measured at 150 ° C. and 190 ° C., and even in a temperature range not lower than the melting point (about 130 ° C.) of the polyethylene resin (B). There is no significant drop. Specifically, the ratio of storage elastic modulus E ′ between 190 ° C. and 150 ° C. (E ′ (190) / E ′ (150)) is 0.3 or more, more preferably 0.3 or more and 1 or less. This is considered to indicate the presence of a typical crosslinked structure.

熱 The thermoplastic elastomer composition of the present invention can exhibit good oil resistance. Specifically, the swelling ratio after immersion in liquid paraffin or oleic acid at 70 ° C. for 24 hours can be 120% by mass or less.

熱 The thermoplastic elastomer composition of the present invention shows good heat resistance. Specifically, the press sheet with the grain was allowed to stand at 110 ° C. for 24 hours, and then the 60 ° gloss value (gloss value at an incident angle of 60 °) of the grain of the press sheet was measured and compared with the gloss value before the test. Preferably, the amount is 1.00% or less. In the case where the heat resistance is low, the grain changes due to heat, so that the rate of change in gloss becomes a larger value.

熱 The thermoplastic elastomer composition of the present invention has good scratch resistance. Specifically, a scratch of 3 cm or more was applied to the mirror surface of the mirror press sheet by using a scratch type hardness meter “318S” manufactured by Eriksen and having a ball tip (ultra-hardness) of 1.0 mm in diameter at a load of 3N. In this case, it is preferable that the scratch depth is 15 μm or less.

The thermoplastic elastomer composition of the present invention can be obtained by a so-called dynamic crosslinking method. Dynamic cross-linking (dynamic vulcanization) is a method in which shearing, dispersion and cross-linking are simultaneously caused by strongly kneading various compounds in a molten state under a temperature condition at which a cross-linking agent reacts. Such a dynamic crosslinking treatment is described, for example, in Reference A. Y. See Coran et al., Rub. Chem. and @Technol. vol. 53.141 to (1980), JSR TECHNICAL REVIEW, No. 112/20050, P20-24. The kneading machine at the time of dynamic crosslinking is usually performed using a closed kneading machine such as a Banbury mixer or a pressure kneader, a single-screw or twin-screw extruder, or the like. The kneading temperature is usually from 130 to 300 ° C, preferably from 150 to 200 ° C. The kneading time is usually 1 to 30 minutes.

架橋 The crosslinking agent in the case of dynamic crosslinking may include an organic peroxide (F). Examples of such an organic peroxide (F) include a phenol resin crosslinking agent, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) -hexane, and 2,5-dimethyl- 2,5-di (tert-butylperoxy) -hexyne-3, di-tert-butyl peroxide and the like. As a crosslinking aid, a polyfunctional monomer such as a maleimide compound, divinylbenzene, TAIC (trimethallyl isocyanurate), or trimethylolpropane trimethacrylate can also be used.

In one embodiment, 1 to 40 parts by mass of the polypropylene resin (C) may be further added to 100 parts by mass of the thermoplastic elastomer composition. By blending 1 part by mass or more of the polypropylene resin, it becomes possible to further improve oil resistance and heat resistance. The softness can be maintained by blending the polypropylene resin in an amount of 40% by mass or less.

In one embodiment, the thermoplastic resin composition is based on 100 parts by mass of the thermoplastic elastomer composition containing the cross copolymer (A) and the polyethylene resin (B), or further blended with the polypropylene resin (C). Further, 1 to 50 parts by mass of a plasticizer (D) and / or 1 to 25 parts by mass of a styrene-based thermoplastic elastomer (E) may be further blended with 100 parts by mass. By using a plasticizer and a styrene-based thermoplastic elastomer in combination, the softness can be improved while preventing the bleed-out of the plasticizer (such as oil).

Examples of the plasticizer (D) include paraffin-based (liquid paraffin, etc.), naphthene-based, aroma-based process oil, mineral oil-based softeners such as liquid paraffin, castor oil, linseed oil, olefin-based wax, mineral-based wax, various types Known compounds such as esters can be used.

As the styrene-based thermoplastic elastomer (E), for example, a thermoplastic elastomer containing a styrene portion can be used. As an example, the “Septon” series (SEP, SEPS, SEEPS, SEBS, SEEPS-OH) sold by Kuraray can be used.

The thermoplastic elastomer composition obtained by blending these polypropylene resin (C), plasticizer (D), and / or styrene thermoplastic elastomer (E) also exhibits excellent A hardness and scratch resistance. And exhibit more excellent oil resistance and heat resistance.

方法 A method of blending the polypropylene resin (C), the plasticizer (D), and / or the styrene thermoplastic elastomer (E) is optional. Preferably, a polypropylene resin (C) and a plasticizer (D) are separately added to the thermoplastic elastomer composition containing the cross copolymer (A) and the polyethylene resin (B) obtained by the dynamic crosslinking method. And / or a styrene-based thermoplastic elastomer (E) is blended and kneaded by a known method. At this time, the same dynamic vulcanization may be performed by using a crosslinking agent or a crosslinking assistant, or the composition may be produced by simply kneading without using these. In particular, in the case of using a polypropylene resin (C), it is finally possible to simply knead the composition without using a cross-linking agent or a cross-linking aid to avoid breaking of the polypropylene chain due to radicals. It is preferable from the viewpoint of heat resistance and oil resistance of the resulting composition.

When compounding the polypropylene resin (C), the plasticizer (D), and / or the styrene thermoplastic elastomer (E), use one twin feed extruder with side feed economically. Can also. Specifically, the main raw materials including the cross-copolymer (A), the polyethylene resin (B), the cross-linking agent, and the like are charged from the raw material inlet, and the cross-linking agent substantially completes the reaction in the extruder region. Dynamic crosslinking is performed, and when the crosslinking agent has substantially completed the reaction, the polypropylene-based resin (C), the plasticizer (D), and / or the styrene-based thermoplastic elastomer (E) are blended from the side feed. By kneading, the thermoplastic elastomer composition (dynamic vulcanizate) containing the cross copolymer (A) and the polyethylene resin (B) is continuously added to the polypropylene resin (C) and the plasticizer (D). And / or a thermoplastic elastomer composition containing a styrene-based thermoplastic elastomer (E).

That is, in one embodiment, there is provided a method for producing a thermoplastic elastomer composition, which comprises a step of mixing at least a cross-copolymer (A), a polyethylene-based resin (B), and a cross-linking agent under shear and further cross-linking the mixture. it can. In one embodiment, the thermoplastic elastomer composition obtained above is further blended with a polypropylene resin (C), a plasticizer (D), and / or a styrene thermoplastic elastomer (E), A method for producing a thermoplastic elastomer composition including a step of kneading can also be provided.

In one embodiment, a molded article using the thermoplastic elastomer composition can be provided. Examples of such a molded article include synthetic leathers and skin materials described in JP-A-2009-102515, WO09 / 128444, WO13 / 018171, or JP-A-2011-153214. It is suitably used for grips or exterior members, foams, skin materials, tape base materials, wire covering materials, gaskets, sheets, or conductive sheets. The sheet using the thermoplastic elastomer composition according to the embodiment of the present invention may be a single layer or a multilayer. In the case of a multilayer, it may be a multilayer further having a layer composed of another resin component, or a multilayer composed only of a layer composed of the present thermoplastic elastomer composition.

In one embodiment, a skin material (for example, a skin material sheet) for an automobile interior having a single-layer or multi-layer sheet containing the thermoplastic elastomer composition can be suitably provided. As such a skin material, a sheet of a thermoplastic elastomer composition can be used for a surface layer, and a foamed polypropylene sheet can be used as a base (base) layer. In this case, in addition to excellent heat resistance, oil resistance, and scratch resistance, thermal adhesiveness to the expanded polypropylene sheet is required. However, the thermoplastic elastomer composition according to the embodiment of the present invention has thermal adhesion to the expanded polypropylene sheet. The properties are good and suitable. In one embodiment, an automobile interior member including the skin material can be provided. Due to the characteristics of the thermoplastic elastomer according to the embodiment of the present invention, there is little odor to humans and low gloss, so that driving is not hindered by the reflection of light incident from outside the window, and the human feel is comfortable. Therefore, an extremely advantageous effect can be obtained as an automobile interior member.

表面 The surface of the single-layer or multi-layer sheet according to the embodiment of the present invention can be subjected to a known surface coating agent treatment in order to further impart texture, scratch resistance, and oil resistance. Such surface coats include, for example, urethane surface coat agents.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but these are only examples and do not limit the content of the present invention. The raw materials and production methods used in Examples and Comparative Examples are as follows.

Cross copolymer (A)
The cross copolymers 1 to 3 shown in Table 1 were used. These cross-copolymers were produced by the production methods of Examples or Comparative Examples described in WO2000 / 37517, WO2007 / 139116 and JP-A-2009-120792. Was similarly determined by the method described in these publications. That is, the composition in the cross-copolymer or ethylene-aromatic vinyl compound-aromatic polyene copolymer, that is, the content of ethylene and aromatic vinyl compound and the content of aromatic vinyl compound polymer are determined by ¹ H-NMR (proton NMR). The content of the aromatic polyene in the ethylene-aromatic vinyl compound-aromatic polyene copolymer was determined from the amount of the aromatic polyene charged during the polymerization and gas chromatographic analysis of the polymerization solution sampled after the completion of the coordination polymerization. The amount of the aromatic polyene used in the polymerization was determined from the difference in the amount of the unreacted aromatic polyene, and the amount was calculated by comparing with the amount of the copolymer obtained by the polymerization. The molecular weight in the polymerization solution was determined by GPC measurement. The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polystyrene chain were determined by GPC measurement of an aromatic vinyl compound polymer separated by solvent fractionation.

In these cross copolymers, the vinyl group hydrogen (proton) peak intensity (area) of the divinylbenzene unit is the same as that of the divinylbenzene unit of the ethylene-styrene-divinylbenzene copolymer obtained in the coordination polymerization step. The strength (area) was less than 20%. In fact, the hydrogen (proton) peak of the vinyl group of the divinylbenzene unit had substantially disappeared in the cross-copolymer after anionic polymerization. The cross copolymer was subjected to Soxhlet extraction using boiling acetone, and the ethylene-styrene-divinylbenzene copolymer chain (essentially, ethylene-styrene copolymer chain) and polystyrene chain included were extracted. Could not be separated. In order to define the cross copolymer, the styrene content, divinylbenzene content, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), cross copolymer of the ethylene-styrene-divinylbenzene copolymer used are specified. The content of the ethylene-styrene-divinylbenzene copolymer, the weight average molecular weight (Mw) of the polystyrene chain, the molecular weight distribution (Mw / Mn), and the MFR (JIS # K7210-1, 200 ° C., 49N) are shown. The gel content measured by ASTM-D2765-84 was less than 0.1% by mass (lower detection limit or less) in any of the cross copolymers.

The measurement conditions of GPC (gel permeation chromatography) were as follows.
<GPC measurement conditions>
Equipment name: HLC-8220 (manufactured by Tosoh Corporation)
Column: 4 Shodex GPC KF-404HQ in series Temperature: 40 ° C
Detection: Differential refractive index Solvent: Tetrahydrofuran Calibration curve: Prepared using standard polystyrene (PS).

Polyethylene resin (B) and other raw materials are as shown in Table 2.

(4) The raw materials shown in Tables 1 and 2 were dynamically vulcanized under the following conditions with the compositions shown in Table 3 to obtain the thermoplastic elastomer compositions of Examples 1 to 9. Similarly, thermoplastic elastomer compositions of Comparative Examples 1 to 4 were obtained. The evaluation results are shown in Tables 3a and 3b.

(Dynamic crosslinking)
The cross copolymer (A), the polyethylene resin (B), and the organic peroxide (F) were mixed with a Henschel mixer for 1 minute. The obtained mixture was kneaded using a twin-screw extruder (TEM35B manufactured by Toshiba Machine Co., Ltd.) at a resin temperature of 220 ° C., a screw rotation speed of 170 rpm, and a residence time of 120 seconds, and was extruded into a strand from a die, cut and heated. A plastic elastomer composition was obtained.

(Preparation of test pieces)
The sheet was prepared according to the following. A sample for physical property evaluation was a square mirror-surface pressed sheet having a thickness of 1 mm and 0.3 mm formed by a heat press method (200 ° C., time: 5 minutes, pressure: 50 kg / cm ² ) using a mirror surface mold (manufactured by STAVAX). Was used. As the press sheet with a single-sided grain, a grain mold was used, and a press sheet with a single-sided grain having a thickness of 0.6 mm, in which a crimp pattern was applied to one side of the sheet by the same heating press method, was used.

(Soft)
In accordance with JIS K6253-3: 2012, the instantaneous hardness was determined using a type A durometer hardness. Six 1 mm-thick square mirror-finished press sheets were used as test pieces. In addition, A hardness 95 or less was set to a preferable level.

(High temperature oil resistance)
A mirror-finished press sheet with a single-sided grain having a thickness of 0.6 mm and a side of 20 mm is placed in a 60 mL plastic bottle containing 4 g of liquid paraffin, (Hi-Kol K-350 manufactured by Kaneda) or oleic acid (first grade manufactured by Junsei Chemical Co., Ltd.). After being immersed above and left at 70 ° C. for 24 hours, the press sheet was taken out and weighed, and the swelling ratio of the press sheet was calculated by comparing with the weight before the test. In addition, the swelling rate of 120 wt% or less was regarded as a pass level.

(Heat-resistant)
After leaving a mirror-finished pressed sheet with a thickness of 0.6 mm and one side of 50 mm on each side at 110 ° C. for 24 hours, measure the 60 ° gloss value of the pressed sheet textured surface and compare it with the gloss value before the test to obtain a pressed sheet textured surface. Was calculated. A gloss change value of 1.00% or less was regarded as a pass level.

(Scratch resistance)
On a specular side of a specular press sheet with a thickness of 0.6 mm and a side of 50 mm on each side, a scratch-type hardness meter “318S” manufactured by Ericssen having a 1.0 mm-diameter ball tip (ultra-hardness) is used on the specular side. Scratches of 3 cm or more. The depth of the groove at the center of the scratch (the portion intersecting with the center line of the press sheet) was measured using a surface roughness measuring device (Surfcoder ET4000AK manufactured by Kosaka Laboratory Co., Ltd.). In addition, 15 micrometers or less of damage depths were set as the pass level.

(MFR)
It measured at 230 degreeC and 10 kg of load based on JIS7210. In addition, 0.3 g / 10 min or more and 10 g / 10 min or less were regarded as acceptable levels.

(Gel fraction)
A mirror pressed sheet with a single-sided grain having a thickness of 0.6 mm was cut into a width of 1 mm and a length of 3 mm, and 0.2 g of the sheet was immersed in xylene at 140 ° C. for 8 hours, and the insoluble matter was filtered off with a 200-mesh metal mesh filter. From the dry weight, the xylene-insoluble gel content was calculated as mass%. The gel fraction of 1.0% by mass or more was regarded as an acceptable level, and the range of 3.0% by mass to 60% by mass was particularly preferred.

(Storage modulus E ')
A measurement sample (8 mm × 50 mm) was cut out from a 0.3 mm-thick square mirror-finished press sheet, and a dynamic viscoelasticity measuring device (RSA-III manufactured by Rheometrics) was used at a frequency of 1 Hz and a temperature rise of 4 ° C./min. The storage elastic modulus E ′ was determined in the temperature range of 30 ° C. to 200 ° C. The storage elastic modulus E ′ at 150 ° C. was 1 × 10 ⁵ Pa or more and 5 × 10 ⁶ Pa or less, and the acceptable level was 1 × 10 ⁵ Pa or more and 2 × 10 ⁶ Pa or less. When the ratio of storage modulus E ′ at 190 ° C. and 150 ° C. (E ′ (190) / E ′ (150)) is 0.3 or more, it is considered that a typical crosslinked structure is present. Therefore, the pass level was set.

Each of the thermoplastic elastomer compositions according to the examples, including the cross copolymer (A) and the polyethylene resin (B), and dynamically crosslinked in the presence of a peroxide, has a suitable MFR value and storage elasticity. It shows that the resin composition has good softness and good high-temperature oil resistance, heat resistance, and scratch resistance. On the other hand, when the polyethylene-based resin (B) is not used, in the viscoelastic spectrum measurement, the resin melts before reaching the measurement temperature of 150 ° C., and the storage elastic modulus becomes lower than the lower limit of measurement, Heat resistance and high temperature oil resistance were also insufficient (Comparative Example 1). If the blending amount of the polyethylene resin (B) is too large, the softness is lost (Comparative Example 2). When dynamic crosslinking is performed using only the polypropylene-based resin (C) instead of the polyethylene-based resin (B), the resulting composition has an excessively high MFR value, and particularly has not achieved high-temperature oil resistance (Comparative Example). 3). In the case of the composition using the polyethylene resin (B) and not performing the dynamic crosslinking without using the crosslinking agent, in the viscoelastic spectrum measurement, the composition melts before reaching the measurement temperature of 150 ° C., and the storage elasticity is increased. The ratio was below the lower limit of the measurement, the gel content was small, and the heat resistance and oil resistance at high temperatures were insufficient (Comparative Example 4).

FIG. 1 shows a graph of the temperature change of the storage elastic modulus for Examples 1 to 3 and Comparative Example 3 as typical examples of the examples. The storage elastic modulus of the thermoplastic elastomer composition according to the present example, which contains the cross copolymer (A) and the polyethylene resin (B) and is dynamically crosslinked in the presence of a peroxide, is determined by the polyethylene resin ( There is no significant decrease in the temperature range above the melting point of B) (about 130 ° C.). Specifically, the ratio of storage elastic modulus E ′ between 190 ° C. and 150 ° C. (E ′ (190) / E ′ (150)) is 0.3 or more, more preferably 0.3 or more and 1 or less. This is considered to indicate the presence of a typical crosslinked structure. In FIG. 1, the unit on the vertical axis is Pa, the horizontal axis is temperature, and the unit is ° C. For example, 1. What is indicated as E + 07 means 1.0 × 10 ⁷ .

On the other hand, the thermal cross-link according to Comparative Example 3, which included the cross-copolymer (A) and the polypropylene-based resin (C) but did not include the polyethylene-based resin (B), and was dynamically crosslinked in the presence of a peroxide. The plastic elastomer composition melts at a temperature equal to or higher than the melting point (approximately 170 ° C.) of the polypropylene resin (C), and the storage elastic modulus E ′ sharply decreases. At 190 ° C., it is below the lower limit of measurement (1 × 10 ⁴ Pa). Specifically, the ratio of storage elastic modulus between 190 ° C. and 150 ° C. (E ′ (190) / E ′ (150)) is 0. 01 or less. When only the cross-copolymer (A) and the polypropylene-based resin (C) are included and the dynamic cross-linking is performed in the presence of a peroxide, the cross-linked structure related to the polypropylene-based resin (C) is substantially small. It is considered to indicate.

Further, using the thermoplastic elastomer composition obtained in Example 2, a polypropylene resin, a plasticizer, and a styrene thermoplastic elastomer shown in Table 4 were blended and kneaded, whereby the thermoplastic elastomers of Examples 10 to 14 were mixed. A composition was obtained. Evaluation results of commercially available TPV-based skin materials, TPS-based skin materials, and PVC-based skin materials are also described as Comparative Examples 5 to 7. Table 5 shows the blending of the raw materials and the evaluation results. The thermoplastic elastomer composition of the example exhibited excellent scratch resistance while having the same level of heat resistance and oil resistance as compared with the commercially available TPV and TPS skin materials of the comparative example. The thermoplastic elastomer compositions of the examples exhibited excellent oil resistance and heat resistance as compared with the PVC skin material.

Further, the thermoplastic elastomer composition obtained in Example 12 was extruded by an extrusion sheet molding machine with a T-die set at a die temperature of 200 ° C., and simultaneously extruded, and a 1.0 mm-thick foamed PP sheet (Toray Pef # 10010AP67 manufactured by Toray Industries, Inc.) ) And a grain roll immediately after the die were subjected to heat fusion to obtain a grained multilayer sheet according to Example 15. The thickness of this multilayer sheet was 1.5 mm. The obtained multilayer sheet was subjected to vacuum forming using an instrument panel mold made of a polypropylene resin at a sheet surface temperature of 110 ° C. to obtain an instrument panel-type automobile interior member. Table 6 shows the evaluation criteria and results.

(Heat cycle test)
With respect to the instrument panel-type automobile interior member, a heat cycle test of 10 cycles was carried out with 80 ° C. for 4 hours to −30 ° C. for 2 hours as one cycle. After the test, the instrument panel-type automobile interior member was left at room temperature for 1 hour or more, and then, at a part designated at five places at random, L * was measured using a colorimetric colorimeter (ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.). , A *, and b * were measured, and the average value was used as a reference value. The color difference ΔE was calculated by comparing the average value of L *, a *, and b * before the test. The color difference ΔE 2.0 or less was regarded as a pass level.

In addition, the appearance of the instrument panel-type automobile interior member after the heat cycle test was visually confirmed, and it was confirmed that there was no deformation, crack, or peeling.

(chemical resistance)
A glass cleaner (HONDA's genuine product number 08CBC-B010L1) was spread on the surface of the instrument panel-type automobile interior member so as to have an application amount of about 0.4 g / 100 cm ² . After being left at 80 ° C. for 48 hours, the appearance of the instrument panel-type automobile interior member was visually checked, and it was confirmed that there was no deformation, crack, or peeling.

(Scratch resistance)
A test piece having a diameter of about 120 mm was cut out from an instrument panel-type automobile interior member, a hole having a diameter of about 6 mm was formed in the center thereof, and a tungsten carbide test piece (HA-201 manufactured by Tester Sangyo Co., Ltd.) was used. A cutter was attached, and a scratch of 3 cm or more was drawn under the conditions of a rotation speed of 0.5 rpm and a load of 3 N. The test pieces after the test were visually checked and classified according to the following evaluation criteria. In addition, grade 4 or higher was considered as a pass.
5th grade: not recognized at all 4th grade: slightly recognized but hardly noticeable 3rd grade: slightly but clearly recognized 2nd grade: somewhat remarkable 1st grade: considerably remarkable

(Light fastness)
Regarding the instrument panel-type automobile interior member, a black panel temperature of 89 ° C., a humidity of 50% RH, and an irradiance of 100 W / m were applied using a xenon weathering tester (Atlas Ci4000 manufactured by Toyo Seiki Seisaku-Sho, Ltd.) in accordance with JIS B7754. ^{2. A} light resistance test was performed under the condition of a radiation exposure amount of 75 MJ / m ² . After the test, the instrument panel-type automobile interior member was left at room temperature for 1 hour or more, and then, at a part designated at five places at random, L * was measured using a colorimetric colorimeter (ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.). , A *, and b * were measured, and the average value was used as a reference value. The color difference ΔE was calculated by comparing the average value of L *, a *, and b * before the test. The color difference ΔE 2.0 or less was regarded as a pass level.

Claims

A cross-copolymer (A) containing 50 to 85% by mass and a polyethylene resin (B) 15 to 50% by mass,
MFR (230 ° C., 10 kg load) is 0.3 g / 10 min or more and 10 g / 10 min or less, and contains a gel content of 1.0 mass% or more;
Thermoplastic elastomer composition.
2. The thermoplastic elastomer composition according to claim 1, wherein the storage elastic modulus E ′ measured at 150 ° C., a frequency of 1 Hz, and a temperature rise of 4 ° C./min is in a range of 1 × 10 5 to 5 × 10 6 Pa. .
Under the conditions of 150 ° C., a frequency of 1 Hz, and a temperature rise of 4 ° C./min, the storage elastic modulus E ′ can be measured at 150 ° C. and 190 ° C., and the ratio of the storage elastic modulus E ′ between 190 ° C. and 150 ° C. (E ′ ( The thermoplastic elastomer composition according to claim 1, wherein (190) / E '(150)) is 0.3 or more.
The cross copolymer (A) has a structure in which an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. 4. The thermoplastic elastomer composition according to claim 1, which is a copolymer satisfying at least one of the following conditions (1) to (3).
(1) The content of the aromatic vinyl compound monomer unit of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the content of the aromatic polyene monomer unit is 0.01 mol% or more. 0.5 mol% or less, the balance being the content of olefin monomer units.
(2) The olefin-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw / Mn) of 1.8 or more and 6 or less.
(3) The content of the olefin-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is in the range of 60 to 95% by mass.
The cross copolymer (A) has a structure in which an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein the copolymer satisfies at least one of the following conditions (1) to (3).
(1) The content of the aromatic vinyl compound monomer unit of the ethylene-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the content of the aromatic polyene monomer unit is 0.01 mol% or more. 0.5 mol% or less, with the balance being the ethylene monomer unit content.
(2) The ethylene-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw / Mn) of 1.8 or more and 6 or less.
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is in the range of 70 to 95% by mass.
The cross copolymer (A) is composed of 70 to 95% by mass of an olefin-aromatic vinyl-aromatic polyene copolymer having an aromatic vinyl monomer unit content of 10 to 30% by mole, and aromatic vinyl monomer. 5 to 30% by mass of an aromatic vinyl polymer comprising monomer units, and the olefin-aromatic vinyl-aromatic polyene copolymer and the aromatic vinyl polymer cannot be substantially separated by solvent separation. The thermoplastic elastomer composition according to any one of claims 1 to 5.
The thermoplastic elastomer composition according to any one of claims 1 to 6, wherein the polyethylene resin (B) is a high-density polyethylene (HDPE).
A thermoplastic elastomer composition further comprising 1 to 40 parts by mass of a polypropylene resin (C) based on 100 parts by mass of the thermoplastic elastomer composition according to any one of claims 1 to 7.
9. The thermoplastic elastomer composition according to claim 1 or 8, further comprising 1 to 50 parts by mass of a plasticizer (D) and / or 1 to 25 parts by mass of a styrene-based thermoplastic elastomer (E). A thermoplastic elastomer composition that is blended.
成形 A molded article comprising the thermoplastic elastomer composition according to any one of claims 1 to 9.
The molded article according to claim 10, which is a sheet.
A multilayer sheet comprising the sheet according to claim 11.
The molded article according to claim 10, wherein a change in specular gloss measured at an incident angle of 60 ° after exposure to a 110 ° C environment for 24 hours is 1.0% or less.
表 A skin material comprising the sheet according to claim 11 or the multilayer sheet according to claim 12.
An automobile interior member including the skin material according to claim 14.
(4) A method for producing a thermoplastic elastomer composition, comprising a step of mixing a cross-copolymer (A), a polyethylene-based resin (B), and a crosslinking agent under shear and crosslinking.
Synthesizing an olefin, an aromatic vinyl compound, and an aromatic polyene monomer using a coordination polymerization catalyst to synthesize an olefin-aromatic vinyl compound-aromatic polyene copolymer;
An aromatic vinyl compound monomer and an anionic polymerization initiator are added to the obtained olefin-aromatic vinyl compound-aromatic polyene copolymer, and anion polymerization is performed to obtain the cross copolymer (A). 17. The method according to claim 16, further comprising the steps of:
A step of blending and kneading a polypropylene-based resin (C), a plasticizer (D), and / or a styrene-based thermoplastic elastomer (E) with the thermoplastic elastomer composition obtained in claim 16 or 17. A method for producing a thermoplastic elastomer composition, comprising: