JP2010248328A - Thermoplastic elastomer composition and hot-melt sealant comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition which maintains good processability and flexibility and has remarkably improved heat resistance, and to provide a hot-melt sealant comprising the same. <P>SOLUTION: This thermoplastic elastomer composition comprises 100 pts.mass of a hydrogenated block copolymer (I) produced by hydrogenating a block copolymer comprising at least a polymer block (A) consisting mainly of aromatic vinyl compound units and a polymer block (B) consisting mainly of conjugated diene units, and having a weight-average mol.wt. of 370,000 to 500,000 and a heat of crystal fusion of 5 to 25 mJ/mg; 100 to 900 pts.mass of a rubber softener (II); and 1 to 50 pts.mass of a polyolefin resin (III). The hot-melt sealant comprises the same. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition and a hot melt sealant comprising the same, which have improved heat resistance while maintaining processability and flexibility.

Sealants are used in a wide range of industrial fields such as architecture, electricity, and automobiles. There are two types of sealants: cross-linked and hot-melt types. Cross-linked types include silicone-based sealants, urethane-based sealants, polysulfide-based sealants, and vulcanized rubber-based sealants. Hot-melt types include EVA-based sealants and soft vinyl chloride-based sealants. And thermoplastic elastomer sealants. In recent years, with the enhancement of functions of products, there has been a demand for better sealing performance with sealants and ease of disassembly during re-installation and recycling.
Among these sealants, a thermoplastic elastomer sealant made of a thermoplastic elastomer composition is suitable in that it has rubber elasticity and high sealability can be obtained by pressurization, and that it can be easily disassembled due to non-crosslinking. However, heat resistance (high rubber elasticity at high temperatures and less change in elasticity over time due to plastic deformation at high temperatures) is inferior to cross-linked type, resulting in long-term sealing performance at high temperatures. It is pointed out that it cannot be maintained.

As a thermoplastic polymer composition having improved heat resistance, a thermoplastic polymer composition comprising a block copolymer having a number average molecular weight of 250,000 or more, a non-aromatic rubber softener and a polyethylene resin has been proposed. (See Patent Document 1). A thermoplastic elastomer composition comprising a hydrogenated block copolymer having a weight average molecular weight of 250,000 or more, a non-aromatic rubber softener, and a crystalline polyolefin is known (see Patent Document 2). Furthermore, hydrogenated paraffin process oil, high molecular weight styrene block copolymer, polyphenylene ether resin or modified polyphenylene ether resin, antioxidant and amorphous polyalphaolefin are blended as a hot melt composition with improved thermal degradation. A hot melt composition is known (see Patent Document 3).

JP 2001-240720 A JP 2002-226666 A JP 2005-97360 A

The compositions described in Patent Documents 1 and 2 improve the heat resistance and reduce the compression set by using a block copolymer having a high molecular weight (about 350,000 weight average molecular weight). There was a need for better heat resistance. However, when a block copolymer having a higher molecular weight (for example, a weight average molecular weight of 370,000 or more) is used in order to further improve the heat resistance, the workability is remarkably lowered, and the composition is obtained by kneading each component. It turns out that there are problems that are difficult to obtain. Further, even in the case of a composition using a high molecular weight block copolymer, when the block copolymer does not have heat of crystal melting, the elasticity at a high temperature (for example, 120 ° C.) becomes low, In some cases, it was difficult to obtain a high sealing performance. Furthermore, as disclosed in Patent Document 3, a composition containing amorphous polyalphaolefin has a problem that it is poor in heat resistance because it easily undergoes plastic deformation.

As a result of intensive studies to achieve the above problems, the present inventors have identified a styrene block copolymer, a rubber softener and a polyolefin resin having a specific range of weight average molecular weight and heat of crystal fusion. The present inventors have found that the heat resistance can be remarkably improved while maintaining the workability and flexibility by using the thermoplastic elastomer composition contained in the above ratio, thereby completing the present invention.
That is, the present invention provides the following (1) and (2).
(1) A weight average molecular weight 370 in which a block copolymer composed at least of a polymer block (A) mainly composed of aromatic vinyl compound units and a polymer block (B) mainly composed of conjugated diene units is hydrogenated. 100 parts by mass of a hydrogenated block copolymer (I) having a heat of crystal melting of 5 to 25 mJ / mg,
A thermoplastic elastomer composition containing 100 to 900 parts by mass of a rubber softener (II); and a polyolefin resin (III).
(2) A hot melt sealant comprising the thermoplastic elastomer composition of (1).

ADVANTAGE OF THE INVENTION According to this invention, the thermoplastic elastomer composition which improved heat resistance markedly while maintaining workability and a softness | flexibility, and a hot melt sealant consisting thereof can be provided.

The thermoplastic elastomer composition of the present invention is a thermoplastic elastomer composition containing hydrogenated block copolymer (I), rubber softener (II) and polyolefin resin (III) as essential components.
[Hydrogenated block copolymer (I)]
The hydrogenated block copolymer (I) is a hydrogenated block copolymer comprising at least a polymer block (A) mainly composed of aromatic vinyl compound units and a polymer block (B) mainly composed of conjugated diene units. A hydrogenated block copolymer added, having a weight average molecular weight of 370,000 to 500,000 and a heat of crystal melting of 5 to 25 mJ / mg.
In order to obtain a thermoplastic elastomer composition having remarkably improved heat resistance, it is important to control the weight average molecular weight and heat of crystal melting of the hydrogenated block copolymer (I) within the above ranges. Hereinafter, specific examples of the polymer block (A), the polymer block (B), and the hydrogenated block copolymer (I) constituting the hydrogenated block copolymer (I) will be described.

<Polymer block (A)>
The polymer block (A) of the hydrogenated block copolymer (I) is mainly composed of structural units (aromatic vinyl compound units) derived from an aromatic vinyl compound. Here, “mainly” means that the aromatic vinyl compound unit is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass based on the mass of the polymer block (A). It means that there is.
Examples of the aromatic vinyl compound constituting the polymer block (A) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, vinylnaphthalene, vinylanthracene, p. -Propylstyrene, pt-butylstyrene, p-cyclohexylstyrene, p-dodecylstyrene, 2-ethyl-4-benzylstyrene, p- (phenylbutyl) styrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene , Methoxystyrene, indene and the like.
The polymer block (A) may contain only a structural unit derived from one kind of the above-described aromatic vinyl compound, or may contain a structural unit derived from two or more kinds. Among them, the polymer block (A) is preferably mainly composed of structural units derived from styrene, α-methylstyrene, and p-methylstyrene.

The polymer block (A) may contain a small amount of a structural unit derived from another copolymerizable monomer together with a structural unit derived from an aromatic vinyl compound. At this time, the ratio of the structural unit derived from the other copolymerizable monomer is preferably less than 30% by mass based on the mass of the polymer block (A), and more preferably less than 10% by mass. preferable.
Examples of other copolymerizable monomers include monomers capable of anionic polymerization such as methacrylic acid ester, acrylic acid ester, 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether. The bonding form of the units based on these other copolymerizable monomers may be any form such as random or tapered.

The polymer block (B) of the hydrogenated block copolymer (I) is mainly composed of structural units derived from conjugated dienes (conjugated diene units). Here, “mainly” means that the conjugated diene unit is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass based on the mass of the polymer block (B). Means.
Examples of the conjugated diene constituting the polymer block (B) include isoprene, butadiene, hexadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and the like.
This polymer block (B) may be comprised only from the structural unit derived from 1 type of above described conjugated diene, and may be comprised from the structural unit derived from 2 or more types. Among these, the polymer block (B) is preferably mainly composed of structural units derived from butadiene or a mixture of butadiene and isoprene. When the polymer block (B) has a structural unit derived from two or more kinds of conjugated dienes, the bonding form thereof is random, block, tapered, or a combination of two or more thereof. be able to.

The polymer block (B) may have a small amount of a structural unit derived from another copolymerizable monomer together with a structural unit derived from a conjugated diene as long as the object of the present invention is not impaired. At this time, the proportion of the structural unit derived from the other copolymerizable monomer is preferably less than 30% by mass based on the mass of the polymer block (B), and more preferably less than 10% by mass. preferable.
Examples of other copolymerizable monomers include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, diphenylethylene, 1-vinylnaphthalene, 4- Examples include anion polymerizable monomers such as aromatic vinyl compounds such as propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, and 4- (phenylbutyl) styrene. These other copolymerizable monomers can be used alone or in combination of two or more. When a structural unit derived from a conjugated diene and a structural unit derived from another copolymerizable monomer such as an aromatic vinyl compound are copolymerized, their bonding form may be either random or tapered.

The polymer block (B) is a carbon derived from a conjugated diene from the viewpoint of making the resulting thermoplastic elastomer composition highly elastic and having excellent compatibility with polyolefin, weather resistance, and heat resistance. -Some or all of the carbon double bonds need to be hydrogenated (hydrogenated). The hydrogenation rate (hydrogenation rate) of the polymer block (B) is preferably 80 mol% or more, more preferably 95 mol% or more, and still more preferably 97 mol% or more.
The hydrogenation rate is determined by measuring the content of carbon-carbon double bonds derived from the conjugated diene in the polymer block (B) before and after hydrogenation, by measuring iodine value, infrared spectrophotometer, ¹ H- It can be measured from an NMR spectrum or the like and obtained from the measured value.

The polymer block (B) is preferably the following polymer block from the viewpoints of elasticity, compatibility with polyolefin, weather resistance, heat resistance and the like.
(I) A polybutadiene block composed of structural units derived from butadiene.
(Ii) A butadiene / isoprene copolymer block composed of structural units derived from a mixture of butadiene and isoprene.
In particular, it is preferable that the polymer block (B) is the butadiene / isoprene copolymer block (ii) composed of a butadiene unit and an isoprene unit, because the resulting thermoplastic elastomer composition is excellent in elasticity.

In the (i) polybutadiene block, 70 to 10 mol%, particularly 65 to 20 mol% of the units derived from the butadiene are 2-butene-1,4-diyl groups [—CH ₂ —CH═CH—CH ₂ —. 1,4-bonded butadiene units], and 30 to 90 mol%, particularly 35 to 80 mol% is a vinylethylene group [—CH (CH═CH) —CH ₂ —; 1,2-bonded butadiene units]. Preferably there is. When the content of 1,4-bonded butadiene units (1,4-bonding amount) in the polybutadiene block is within the above-described range, the rubber elasticity of the resulting thermoplastic elastomer composition is improved.

In the above (ii) butadiene / isoprene copolymer block, the unit derived from butadiene consists of 2-butene-1,4-diyl group and vinylethylene group, and the unit derived from isoprene is 2-methyl- 2-butene-1,4-diyl group [—CH ₂ —C (CH ₃ ) ═CH—CH ₂ —; 1,4-bonded isoprene unit], isopropenylethylene group [—CH (C (CH ₃ ) = CH ₂ ) —CH ₂ —; 3,4-bonded isoprene unit] and 1-methyl-1-vinylethylene group [—C (CH ₃ ) (CH═CH ₂ ) —CH ₂ —; 1,2-bonded isoprene Unit], and the ratio of each unit is not particularly limited. In the butadiene / isoprene copolymer block, the arrangement of butadiene units and isoprene units may be any of random, block, and tapered shapes.
In the butadiene / isoprene copolymer block, the molar ratio of butadiene unit: isoprene unit is preferably 10:90 to 90:10 from the viewpoint of the effect of improving the rubber elasticity of the thermoplastic elastomer composition obtained, : 70 to 70:30 is more preferable.

The hydrogenated block copolymer (I) used in the present invention is a hydrogenated block copolymer obtained by hydrogenating a block copolymer containing at least one polymer block (A) and a polymer block (B). It is. Preferably, the hydrogenated block copolymer (I) is a hydrogenated block copolymer obtained by hydrogenating a block copolymer containing one or more polymer blocks (A) and two or more polymer blocks B. is there. The bonding form of the polymer block (A) and the polymer block (B) is not particularly limited, and may be any of linear, branched, radial, or a combination of two or more thereof. . The content of the polymer block (A) is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, and particularly preferably 25 to 50% by mass with respect to the total amount of the hydrogenated block copolymer (I). . When the content of the polymer block (A) is less than 10% by mass, the resulting thermoplastic elastomer composition may be inferior in heat resistance, whereas when it exceeds 60% by mass, The melt viscosity of the polymer (I) tends to be too high and the processability tends to be inferior, and the flexibility of the resulting thermoplastic elastomer composition may be poor.

<Properties of hydrogenated block copolymer (I)>
As a specific example of the hydrogenated block copolymer (I), when the polymer block (A) is represented by A and the polymer block (B) is represented by B, the diblock represented by [AB] A block copolymer, a triblock copolymer represented by [A-B-A] or [B-A-B], a tetra-block copolymer represented by [A-B-A-B], or A polyblock copolymer in which 5 or more of A and B are linearly bonded, (AB) nX type copolymer (X represents a coupling residue, and n represents an integer of 3 or more. ), And hydrogenated products such as mixtures thereof. Among these, the triblock copolymer represented by [ABA], the pentablock copolymer represented by [ABABABA], and the (AB) nX type copolymer. A hydrogenated product of a polymer is preferable, and a hydrogenated product of a triblock copolymer represented by [ABA] is more preferable from the viewpoint of production stability and flexibility of a thermoplastic elastomer composition to be obtained. .
Here, in the present specification, when the same kind of polymer block is linearly bonded via a divalent coupling agent or the like, the entire bonded polymer block is handled as one polymer block. It is. Accordingly, strictly including the above-described examples, the polymer block that should be originally expressed as [A-X-A] is, as a whole, unless otherwise required to be distinguished from the single polymer block A. Is displayed. In the present specification, this type of polymer block containing a coupling agent residue is handled as described above, and therefore, for example, it contains a coupling agent residue, and strictly speaking, [A-B-X-B-A ] A block copolymer to be represented as [ABA] is treated as an example of a triblock copolymer.

In the hydrogenated block copolymer (I), the molecular weight of the polymer block (A) and the polymer block (B) is not particularly limited, but the heat resistance and processability of the resulting thermoplastic elastomer composition are not limited. From the viewpoint, the weight average molecular weight of the polymer block (A) is preferably 20,000 to 80,000, the weight average molecular weight of the polymer block (B) is preferably 50,000 to 340,000, and more Preferably it is 210,000-340,000.
The total weight average molecular weight of the hydrogenated block copolymer (I) needs to be 370,000 to 500,000, preferably 400,000 to 490,000, more preferably 420,000. ~ 480,000. If the weight average molecular weight of the hydrogenated block copolymer (I) is less than 370,000, the resulting thermoplastic elastomer composition may not have sufficient heat resistance, and if it exceeds 500,000, the resulting thermoplasticity The elastomer composition may be inferior in processability.
In addition, the weight average molecular weight as used in this specification is the value calculated | required from the standard polystyrene calibration curve by the gel permeation chromatography (GPC) method.

The hydrogenated block copolymer (I) needs to have a heat of crystal melting of 5 to 25 mJ / mg, preferably 7 to 23 mJ / mg, more preferably 9 to 22 mJ / mg. If the hydrogenated block copolymer (I) does not have a heat of crystal fusion, or if the heat of crystal fusion is less than 5 mJ / mg, the resulting thermoplastic elastomer composition may not have sufficient heat resistance, and 25 mJ If it exceeds / mg, the flexibility of the resulting thermoplastic elastomer composition may be impaired. The heat of crystal fusion of the hydrogenated block copolymer (I) can be controlled by adjusting the kind of conjugated diene constituting the polymer block (B), the copolymerization ratio, the 1,4-bond amount, and the like. .
The crystal melting heat can be measured by a differential scanning calorimetry (DSC) apparatus.

<Production of hydrogenated block copolymer (I)>
"polymerization"
The method for producing the hydrogenated block copolymer (I) is not limited at all, and for example, it can be produced by performing a known polymerization method such as an ionic polymerization method such as anionic polymerization or cationic polymerization, or a radical polymerization method. For example, in the case of anionic polymerization, a block copolymer is obtained by sequentially polymerizing an aromatic vinyl compound and a conjugated diene in an organic solvent inert to a polymerization reaction such as n-hexane and cyclohexane using an alkyl lithium compound as an initiator. Form.

《Hydrogenation》
The hydrogenation reaction of the block copolymer obtained above is carried out, for example, in the presence of a catalyst in a saturated hydrocarbon solvent such as cyclohexane, usually at a reaction temperature of 20 to 100 ° C. The hydrogenation of the block copolymer can be obtained under the conditions of hydrogen pressure of 0.1 to 10 MPa.
As a catalyst for this hydrogenation reaction, Raney nickel; heterogeneous catalyst in which a metal such as Pt, Pd, Ru, Rh, Ni is supported on a carrier such as carbon, alumina, diatomaceous earth; Ziegler-type catalyst consisting of a combination of an organometallic compound composed of a Group 10 metal and an organoaluminum compound such as triethylaluminum or triisobutylaluminum, or an organolithium compound; Enyl) compounds and metallocene catalysts composed of a combination of lithium, sodium, potassium, aluminum, zinc, magnesium and other organic metal compounds.

[Rubber softener (II)]
The rubber softening agent (II) used in the present invention imparts flexibility to the thermoplastic elastomer composition of the present invention and gives high sealing performance by following the unevenness of the adherend. The rubber softener is preferably a non-aromatic one from the viewpoint of imparting flexibility, and can be appropriately selected from conventionally known ones.
Non-aromatic rubber softeners include, for example, paraffinic process oil, naphthenic process oil, ethylene and α-olefin oligomers, liquid paraffin, polybutene, low molecular weight polybutadiene, low molecular weight polyisoprene, and hydrogenated low molecular weight polybutadiene. And hydrogenated low molecular weight polyisoprene. Among these, paraffinic process oil, oligomers of ethylene and α-olefin, and liquid paraffin are preferable. From the viewpoint of not lowering the processability of the thermoplastic elastomer composition obtained, kinematic viscosity at 40 ° C. of softening agent for rubber is preferably in the range of 5~250mm ² / sec, more preferably 6~200mm ² / sec 6 to 150 mm ² / sec is more preferable. When the kinematic viscosity at 40 ° C. is less than 5 mm ² / second, the flammable gas may be volatilized, and when it exceeds 250 mm ² / second, the workability may decrease.

[Polyolefin resin (III)]
Examples of the polyolefin resin (III) used in the present invention include propylene homopolymers or propylene / ethylene copolymers such as homopolypropylene, random polypropylene, block polypropylene, atactic polypropylene, and syndiotactic polypropylene; Butene copolymer, propylene / 1-hexene copolymer, propylene / 1-heptene copolymer, propylene / 1-octene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-nonene Copolymers, propylene / α-olefin copolymers such as propylene / 1-decene copolymer; propylene-based polymers containing modified products thereof such as maleic anhydride, high density polyethylene, medium density polyethylene, low density Polyethylene (LD E) ethylene homopolymers; ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-heptene copolymer, ethylene / 1-octene copolymer, ethylene-4-methyl -1-pentene copolymer, ethylene / 1-nonene copolymer, ethylene / α-olefin copolymer such as ethylene / 1-decene copolymer; ethylene / vinyl acetate copolymer; ethylene / acrylic acid copolymer And ethylene / methacrylic acid copolymers; ethylene polymers containing modified products of these polymers and copolymers, such as maleic anhydride, and the like. May be used in combination. Among these, a crystalline propylene polymer is preferable. Here, the crystalline propylene polymer refers to a propylene polymer having a crystal melting temperature (Tm), that is, a peak top of crystal melting heat measured by DSC of 130 ° C. or higher. In particular, from the viewpoint of heat resistance and processability of the obtained thermoplastic elastomer composition, homopolypropylene and block polypropylene are preferably used, and homopolypropylene is more preferably used. When a crystalline propylene-based polymer is used, it is preferable to use one having a melt flow rate (MFR) in the range of 0.1 to 800 g / 10 min, more preferably in the range of 1 to 50 g / 10 min. preferable.

[Content Ratio of Each Component in Thermoplastic Elastomer Composition]
In the thermoplastic elastomer composition of the present invention, the content of the rubber softening agent (II) is required to be 100 to 900 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (I), and 150 It is preferable that it is -500 mass parts, and it is more preferable that it is 200-400 mass parts. When the content is less than 100 parts by mass, the flexibility may be lowered. On the other hand, when it exceeds 900 parts by mass, sufficient heat resistance may not be obtained.
Further, the content ratio of the polyolefin resin (III) is required to be 1 to 50 parts by mass, and preferably 3 to 30 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (I). 5 to 20 parts by mass is more preferable. If the content is less than 1 part by mass, the workability may be poor, whereas if it exceeds 50 parts by mass, the flexibility may be reduced.

Furthermore, the thermoplastic elastomer composition of the present invention is a thermoplastic elastomer composition obtained even when the content ratio of the polyolefin resin (III) to the total mass of the thermoplastic elastomer composition is as small as 0.5 to 8% by mass. Can maintain the workability. It is surprising that the processability of the thermoplastic elastomer composition can be maintained even when an additive such as a tackifier resin, a softener or a polyphenylene ether resin is added. If the content is less than 0.5% by mass, the workability may be poor, while if it exceeds 8% by mass, the flexibility may decrease.

[Tackifying resin (IV)]
The thermoplastic elastomer composition of the present invention can contain a tackifier resin (IV) for the purpose of improving the adhesion to an adherend. Examples of the tackifier resin (IV) include natural rosin, hydrogenated rosin resin, hydrogenated rosin ester resin, terpene resin, terpene phenol resin, aromatic modified terpene resin, hydrogenated terpene resin, aromatic Examples include modified hydrogenated terpene resins, C5 petroleum resins, C9 petroleum resins, phenolic resins, xylene resins, and alicyclic hydrogenated petroleum resins. Among these, alicyclic hydrogenated petroleum resins, hydrogenated terpene resins, and aromatic-modified hydrogenated terpene resins are preferred from the viewpoint of not damaging the flexibility and heat resistance of the resulting thermoplastic elastomer composition.
When the tackifier resin (IV) is contained, the content is preferably 10 to 300 parts by mass, more preferably 50 to 250 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (I). If the addition amount of the tackifying resin (IV) is less than 10 parts by mass, the effect of improving the tackiness may not be obtained. On the other hand, if it exceeds 300 parts by mass, the heat resistance and flexibility of the thermoplastic elastomer composition obtained. May decrease.

[Filler]
The thermoplastic elastomer composition of the present invention may further contain a filler for the purpose of reducing costs and improving physical properties for special applications. Examples of the filler include calcium carbonate, talc, clay, synthetic silicon, titanium oxide, carbon black, barium sulfate, mica, glass fiber, whisker, carbon fiber, magnesium carbonate, glass bead powder, glass hollow sphere powder, and resin hollow Examples thereof include spherical powder, metal powder, kaolin, graphite, molybdenum disulfide, zinc oxide, and the like, and one or more of these can be contained.
When the filler is contained, the content is preferably in a range that does not impair the object of the present invention, and is generally 10 to 500 parts per 100 parts by mass of the hydrogenated block copolymer (I). It is preferable that it is a mass part, and it is more preferable that it is 20-300 mass parts. When the added amount of the filler is less than 10 parts by mass, the effect of filling the obtained thermoplastic elastomer composition may not be obtained. On the other hand, when the amount exceeds 500 parts by mass, the processability of the obtained thermoplastic elastomer composition may be reduced. Flexibility may be reduced.

（式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立して、水素原子、ハロゲン原子、炭化水素基、置換炭化水素基、アルコキシ基、シアノ基、フェノキシ基又はニトロ基を表し、ｍは重合度を表す整数である。）
好ましいポリフェニレンエーテル系樹脂は、上記式（１）におけるＲ^１及びＲ^２がアルキル基、特に炭素原子数１〜４のアルキル基であり、Ｒ^３及びＲ^４が、水素原子又は炭素原子数１〜４のアルキル基であるポリマーである。ｍは通常５０以上が好ましい。例えば、ポリ（２，６−ジメチル−１，４−フェニレン）エーテル、ポリ（２，６−ジエチル−１，４−フェニレン）エーテル、ポリ（２−メチル−６−エチル−１，４−フェニレン）エーテル、ポリ（２−メチル−６−プロピル−１，４−フェニレン）エーテル、ポリ（２，６−ジプロピル−１，４−フェニレン）エーテル、ポリ（２−エチル−６−プロピル−１，４−フェニレン）エーテル、ポリ（２，６−ジメトキシ−１，４−フェニレン）エーテル、ポリ（２，６−ジクロロメチル−１，４−フェニレン）エーテル、ポリ（２，６−ジブロモメチル−１，４−フェニレン）エーテル、ポリ（２，６−ジフェニル−１，４−フェニレン）エーテル、ポリ（２，６−ジトリル−１，４−フェニレン）エーテル、ポリ（２，６−ジクロロ−１，４−フェニレン）エーテル、ポリ（２，６−ジベンジル−１，４−フェニレン）エーテル、ポリ（２，５−ジメチル−１，４−フェニレン）エーテル等が挙げられる。中でも特に好ましいポリフェニレンエーテル系樹脂は、ポリ（２，６−ジメチル−１，４−フェニレン）エーテルである。またこれらは極性基を有する変性剤により変性されていてもよい。極性基としては、例えば、酸ハライド、カルボニル基、酸無水物、酸アミド、カルボン酸エステル、酸アジド、スルフォン基、ニトリル基、シアノ基、イソシアン酸エステル、アミノ基、イミド基、水酸基、エポキシ基、オキサゾリン基、チオール基等が挙げられる。 本発明で用いるポリフェニレンエーテル系樹脂の分子量は、数平均分子量１，０００〜１００，０００が好ましく、特に各種の物性のバランスを考慮すると６，０００〜６０，０００の範囲のものが更に好ましい。
ポリフェニレンエーテル系樹脂を含有させる場合は、水添ブロック共重合体（Ｉ）１００質量部に対して１〜２００質量部の範囲であることが好ましく、５〜１００質量部であることがより好ましい。ポリフェニレンエーテル系樹脂の添加量が１質量部未満であると得られる熱可塑性エラストマー組成物の耐熱性改善効果が不十分となる場合があり、一方、２００質量部を超えると得られる熱可塑性エラストマー組成物の加工性や柔軟性が低下する場合がある。 [Polyphenylene ether resin]
The thermoplastic elastomer composition of the present invention may further contain a polyphenylene ether resin for the purpose of improving heat resistance. There is no restriction | limiting in particular as polyphenylene ether-type resin used here, A conventionally well-known thing can be used. For example, a polymer represented by the following general formula (1) can be used.

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group, a substituted hydrocarbon group, an alkoxy group, a cyano group, a phenoxy group or a nitro group. , M is an integer representing the degree of polymerization.)
In the preferred polyphenylene ether resin, R ¹ and R ² in the above formula (1) are alkyl groups, particularly alkyl groups having 1 to 4 carbon atoms, and R ³ and R ⁴ are hydrogen atoms or carbon atoms having 1 to ⁴ carbon atoms. 4 is a polymer that is an alkyl group. m is usually preferably 50 or more. For example, poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) Ether, poly (2-methyl-6-propyl-1,4-phenylene) ether, poly (2,6-dipropyl-1,4-phenylene) ether, poly (2-ethyl-6-propyl-1,4-phenylene) Phenylene) ether, poly (2,6-dimethoxy-1,4-phenylene) ether, poly (2,6-dichloromethyl-1,4-phenylene) ether, poly (2,6-dibromomethyl-1,4- Phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2,6-ditolyl-1,4-phenylene) ether, poly (2,6-dichloro-) , 4-phenylene) ether, poly (2,6-dibenzyl-1,4-phenylene) ether, poly (2,5-dimethyl-1,4-phenylene) ether. Among them, a particularly preferable polyphenylene ether resin is poly (2,6-dimethyl-1,4-phenylene) ether. These may be modified with a modifying agent having a polar group. Examples of polar groups include acid halides, carbonyl groups, acid anhydrides, acid amides, carboxylic acid esters, acid azides, sulfone groups, nitrile groups, cyano groups, isocyanate esters, amino groups, imide groups, hydroxyl groups, and epoxy groups. , An oxazoline group, a thiol group, and the like. The molecular weight of the polyphenylene ether resin used in the present invention is preferably a number average molecular weight of 1,000 to 100,000, and more preferably in the range of 6,000 to 60,000 in consideration of the balance of various physical properties.
When the polyphenylene ether-based resin is contained, the content is preferably in the range of 1 to 200 parts by mass, more preferably 5 to 100 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (I). The thermoplastic elastomer composition obtained when the addition amount of the polyphenylene ether-based resin is less than 1 part by mass may be insufficient in the heat resistance improvement effect of the thermoplastic elastomer composition obtained. The workability and flexibility of the object may be reduced.

[Other optional ingredients]
In the thermoplastic elastomer composition of the present invention, as an optional component other than the tackifying resin (IV), the filler, and the polyphenylene ether-based resin, as long as it does not impair the characteristics of the composition, A polymer, a crosslinking agent, a crosslinking aid, an antioxidant, a light stabilizer, an ultraviolet absorber, a flame retardant, an antistatic agent, a lubricant, a colorant, an antibacterial agent, a foaming agent, and the like can be appropriately contained.
<Other polymers>
Examples of the other polymer include styrene resins and rubbers such as polystyrene, syndiotactic polystyrene, styrene / maleic anhydride copolymer resin, styrene / butadiene copolymer rubber, and styrene / isoprene copolymer rubber; Acrylic resins such as methyl acrylate and polymethyl methacrylate; polycarbonate resin; polyamide 6, polyamide 6 · 6, polyamide 6 · 10, polyamide 11, polyamide 12, polyamide 6 · 12, polyhexamethylenediamine terephthalamide, polyhexa Polyamide resins such as methylenediamine isophthalamide and xylene group-containing polyamide; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polyoxymethylene homopolymer, polyoxymethylene copolymer Polyoxymethylene resins such as ethylene / propylene copolymer rubber (EPM), ethylene / propylene / non-conjugated diene copolymer rubber (EPDM); natural rubber; synthetic isoprene rubber, liquid polyisoprene rubber and its hydrogenated product or modification Chloroprene rubber; acrylic rubber; butyl rubber; acrylonitrile-butadiene rubber; epichlorohydrin rubber; silicone rubber; fluoro rubber; chlorosulfonated polyethylene; urethane rubber; polyurethane elastomer; polyamide elastomer; polyester elastomer; Etc.
When these other polymers are contained, the content is preferably within a range in which the characteristics of the obtained thermoplastic elastomer composition are not impaired, and 100 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (I). It is preferable that:

[Preparation of Thermoplastic Elastomer Composition]
As a method for preparing the thermoplastic elastomer composition of the present invention, a method used for preparing a normal thermoplastic resin composition or thermoplastic elastomer composition can be employed. Specifically, using a melt kneader such as a single screw extruder, twin screw extruder, Banbury mixer, heating roll, various kneaders, the hydrogenated block copolymer (I), rubber softener (II), It can be prepared by melt-kneading a polyolefin resin (III), a tackifier resin (IV) used as necessary, and a mixture of various additive components.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. The analysis and physical property evaluation in each example were performed by the following methods.
[analysis]
(1) Hydrogenation rate The hydrogenation rate was determined by measuring the iodine value before and after hydrogenation of the carbon-carbon double bond content based on the conjugated diene in the polymer block (B).
(2) Weight average molecular weight The weight average molecular weight was determined by measuring the hydrogenated block copolymer with a gel permeation chromatography (GPC) apparatus under the following conditions, and obtaining the value in terms of polystyrene.
Column: Trade name: TSKgel G4000H xl, manufactured by Tosoh Corporation (column temperature: 40 ° C.)
-Mobile phase: tetrahydrofuran (flow rate: 1 ml / min)
・ Detector: differential refractometer ・ Standard material: TSK standard polystyrene manufactured by Tosoh Corporation ・ Sample concentration: 5 mg / 10 cc
(3) Heat of crystal melting The heat of crystal melting was determined by measuring the hydrogenated block copolymer with a differential scanning calorie (DSC) device in the range of -100 to 100 ° C (temperature increase rate 10 ° C / min).
(4) 1,4-bond amount 1,4-bond amount was determined by measuring the block copolymer before hydrogenation with a nuclear magnetic resonance (H-NMR) apparatus.
[Physical properties]
(1) Flexibility Based on JIS K 6253, Shore hardness (A type) was measured at a measurement temperature of 23 ° C. using a 6 mm thickness test piece. The hardness value was used as an index of flexibility.
(2) Workability Based on JIS K7210, MFR in 200 degreeC and a 2.16kg load was measured. The MFR value was used as an index of workability.
(3) A compression set of 120 ° C. × 22 hours was measured using a test piece of 29 mmΦ according to JIS K 6262 except for the heat resistance measurement temperature. Compression rate is 25%. The value of compression set was used as an index of heat resistance.

<Production Example 1: Production of hydrogenated block copolymer (I)>
After adding 700 kg of cyclohexane and 323 g of a 10 mass% sec-butyllithium toluene solution (32.3 g in terms of sec-butyllithium) to a pressure-resistant vessel equipped with a stirrer substituted with nitrogen, and stirring and heating to 50 ° C., 15 kg of styrene was added and polymerized for 1 hour. Next, a mixture of 35 kg of butadiene and 35 kg of isoprene was added to this polymerization solution and polymerized for 1 hour, then 15 kg of styrene was added again and polymerized for 1 hour, and the 1,4-bond amount of the conjugated diene moiety was 92%. A cyclohexane solution of a polystyrene-poly (butadiene / isoprene) -polystyrene triblock copolymer was obtained.
Subsequently, 3500 g of a Ziegler catalyst toluene solution (350 g in terms of nickel octylate / triethylaluminum) consisting of a 10 mass% nickel octylate / triethylaluminum mixture was added to the cyclohexane solution of the triblock copolymer with stirring. After hydrogen substitution, the mixture was heated to 80 ° C. and hydrogenated under a hydrogen pressure of 3 MPa for 5 hours to obtain a hydrogenated block copolymer (I).

<Production Example 2: Production of hydrogenated block copolymer-2>
After adding 700 kg of cyclohexane and 299 g of a toluene solution of 10% by mass of sec-butyllithium (29.9 g in terms of sec-butyllithium) to a pressure-resistant vessel equipped with a stirrer purged with nitrogen and stirring and heating to 50 ° C., 15 kg of styrene was added and polymerized for 1 hour. Next, 70 kg of isoprene was added to this polymerization solution and polymerized for 1 hour, and then 15 kg of styrene was added again and polymerized for 1 hour to obtain a polystyrene-polystyrene having a conjugated diene moiety having a 1,4-bond content of 92%. A cyclohexane solution of a triblock copolymer of isoprene-polystyrene was obtained.
Subsequently, 3500 g of a Ziegler catalyst toluene solution (350 g in terms of nickel octylate / triethylaluminum) consisting of a 10 mass% nickel octylate / triethylaluminum mixture was added to the cyclohexane solution of the triblock copolymer with stirring. After hydrogen substitution, the mixture was heated to 80 ° C. and subjected to a hydrogenation reaction under a hydrogen pressure of 3 MPa for 5 hours to obtain a hydrogenated block copolymer-2.

<Production Example 3: Production of hydrogenated block copolymer-3>
After adding 700 kg of cyclohexane and 645 g of a toluene solution of 10% by mass of sec-butyllithium (64.5 g in terms of sec-butyllithium) to a pressure-resistant vessel equipped with a stirrer substituted with nitrogen, and heating to 50 ° C., 15 kg of styrene was added and polymerized for 1 hour. Next, a mixture of 35 kg of butadiene and 35 kg of isoprene was added to this polymerization solution and polymerized for 1 hour, then 15 kg of styrene was added again and polymerized for 1 hour, and the 1,4-bond amount of the conjugated diene moiety was 92%. A cyclohexane solution of a polystyrene-poly (butadiene / isoprene) -polystyrene triblock copolymer was obtained.
Subsequently, 3500 g of a Ziegler catalyst toluene solution (350 g in terms of nickel octylate / triethylaluminum) consisting of a 10 mass% nickel octylate / triethylaluminum mixture was added to the cyclohexane solution of the triblock copolymer with stirring. After hydrogen substitution, the mixture was heated to 80 ° C. and hydrogenated under a hydrogen pressure of 3 MPa for 5 hours to obtain hydrogenated block copolymer-3.

Examples 1-2 and Comparative Examples 1-4
Each component shown in Table 1 was mixed at 230 ° C. for 2 hours using a sigma blade type kneader according to the formulation shown in Table 1 to prepare a sealant composition. Next, from the obtained composition, a predetermined molding was produced at a molding temperature of 230 ° C. using a press molding machine, and the physical properties were evaluated. The results are shown in Table 1.

In addition, the detail of the component shown in Table 1 is as follows.
1) Hydrogenated block copolymer (I): Hydrogenated product of polystyrene-poly (butadiene / isoprene) -polystyrene triblock copolymer obtained in Production Example 1; styrene unit content = 30% by mass, weight average Molecular weight = 400,000, hydrogenation rate = 98.5%, heat of crystal fusion = 18 mJ / mg
2) Hydrogenated block copolymer-2: hydrogenated polystyrene-polyisoprene-polystyrene triblock copolymer obtained in Production Example 2; styrene unit content = 30 mass%, weight average molecular weight = 400,000 , Hydrogenation rate = 99.0%, heat of crystal fusion = 0 mJ / mg
3) Hydrogenated block copolymer-3: hydrogenated polystyrene-poly (butadiene / isoprene) -polystyrene triblock copolymer obtained in Production Example 3; styrene unit content = 30 mass%, weight average molecular weight = 200,000, hydrogenation rate = 98.5%, heat of crystal fusion = 22 mJ / mg
4) Rubber softener (II): Paraffin-based process oil; Idemitsu Kosan Co., Ltd., trade name “Diana Process PW-90”, kinematic viscosity 95.54 mm ² / sec (40 ° C.)
5) Polyolefin resin (III): homopolypropylene resin; manufactured by Nippon Polypro Co., Ltd., trade name “NOVATEC PP MA3”, MFR = 10 g / 10 min
6) Tackifying resin (IV): Hydrogenated alicyclic hydrocarbon resin; manufactured by ExxonMobil, trade name “Escollets ECR-227E”
7) Filler: Glass hollow sphere powder; manufactured by 3M, trade name “Glass Bubbles K-37”
8) Polyphenylene ether resin: modified polyphenylene ether resin; product name "Zylon 500H" manufactured by Asahi Kasei Chemicals
9) Anti-aging agent-1: Hindered phenol-based anti-aging agent; product name “Irganox 1010” manufactured by Ciba Specialty Chemicals
10) Anti-aging agent-2: Phosphorus-based anti-aging agent; trade name “Irgaphos 168” manufactured by Ciba Specialty Chemicals

From Table 1, it can be seen that the thermoplastic elastomer composition obtained in Example 1 or 2 is excellent in heat resistance while maintaining workability and flexibility.
On the other hand, it can be seen that the thermoplastic elastomer composition obtained in Comparative Example 1 is inferior in heat resistance because it uses hydrogenated block copolymer-2 which does not have heat of crystal melting.
Since the thermoplastic elastomer composition obtained in Comparative Example 2 uses hydrogenated block copolymer-3 having a small weight average molecular weight, it can be seen that although it is excellent in workability, it is inferior in heat resistance.
Since the thermoplastic elastomer composition obtained in Comparative Example 3 did not contain the polyolefin resin (III), the thermoplastic elastomer composition was not bundled and could not be kneaded and molded. Therefore, various performances could not be evaluated.
Further, it can be seen that the thermoplastic elastomer composition obtained in Comparative Example 4 is inferior in flexibility because the content of the polyolefin resin (III) is larger than the range specified in the present application.

The thermoplastic elastomer composition of the present invention has remarkably improved heat resistance while maintaining flexibility and processability. For example, as an amorphous sealant that seals in a gap of a connecting portion using a hand gun or the like. Alternatively, a string-like or packing-like molded sealant is produced using extrusion molding, injection molding, or the like, and used for various purposes such as equipment around an automobile engine or a joint part of a device such as a solar panel. be able to.

Claims (6)

A weight average molecular weight of 370,000-, in which a block copolymer comprising at least a polymer block (A) mainly composed of aromatic vinyl compound units and a polymer block (B) mainly composed of conjugated diene units is hydrogenated. 500,000, 100 parts by mass of hydrogenated block copolymer (I) having a crystal melting heat of 5 to 25 mJ / mg;
A thermoplastic elastomer composition containing 100 to 900 parts by mass of a softening agent for rubber (II); and 1 to 50 parts by mass of a polyolefin resin (III).   The thermoplastic elastomer composition according to claim 1, wherein the polymer block (B) is a polymer block comprising a butadiene unit and an isoprene unit.   The thermoplastic elastomer composition according to claim 1 or 2, wherein the polyolefin resin (III) is a crystalline propylene polymer.   The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein a content ratio of the polyolefin resin (III) to the mass of the entire thermoplastic elastomer composition is 0.5 to 8 mass%.   Furthermore, thermoplastic elastomer of any one of Claims 1-4 which contains tackifying resin (IV) in the ratio of 10-300 mass parts with respect to 100 mass parts of hydrogenated block copolymer (I). Composition.   A hot melt sealant comprising the thermoplastic elastomer composition according to any one of claims 1 to 5.