JP6022296B2 - Thermoplastic elastomer composition and molded article comprising the composition - Google Patents

Description

  The present invention relates to a thermoplastic elastomer composition and a molded article comprising the thermoplastic elastomer composition.

  In recent years, thermoplastic elastomer materials that are rubber-elastic soft materials that do not require a vulcanization process and that can be molded and recycled in the same way as thermoplastic resins are used in automotive parts, home appliance parts, electric wire coatings, and medical use. Widely used in the fields of parts, miscellaneous goods, footwear, etc. Among such thermoplastic elastomer materials, an olefinic thermoplastic elastomer composition comprising an olefinic rubber and a polyolefin resin is widely used as an alternative to vulcanized rubber because of its excellent strain recovery at high temperatures. (See Patent Document 1). However, in an elastomer composition containing an olefinic rubber and a molded product comprising the same, the softening agent blended in the elastomer composition bleeds out to the surface of the molded product, resulting in poor appearance of the molded product, poor surface feel due to stickiness, etc. In addition, the surface of the molded body is rough, the smoothness is poor, and the appearance is poor.

  Further, a thermoplastic elastomer composition is known in which a hydrogenated product of a block copolymer composed of an aromatic vinyl compound polymer block and a conjugated diene compound polymer block is blended with an olefin rubber (see Patent Document 2). . Further, a thermoplastic resin having a gel content of 97% or more containing a hydrogenated product and a softening agent of a block copolymer comprising a crystalline polyolefin resin, an olefin rubber, a styrene polymer block and a butadiene and / or isoprene polymer block. Elastomer compositions are known (see Patent Document 3). In these thermoplastic elastomer compositions, the hydrogenated block copolymer consisting of a styrene polymer block and a conjugated diene compound polymer block contained in the composition is excellent in softener retention. In the molded product obtained from the plastic elastomer composition, there are few problems such as bleeding out of the softener from the surface.

Japanese Examined Patent Publication No. 58-46138 JP-A-7-286078 JP-A-8-291239

However, the thermoplastic elastomer composition described above has room for improvement in that the compression set at high temperatures is inferior, and the surface of the molded article is greatly rough and inferior in surface smoothness.
The present invention has been made in view of the above circumstances, and is excellent in molding processability, flexibility, vibration damping properties, compression set at a high temperature and retainability of a softening agent, and has a smooth surface even by extrusion molding. A thermoplastic elastomer composition capable of obtaining a molded article is provided.

That is, the present invention
[1] Containing a polymer block (A) comprising a structural unit derived from an olefinic rubber (I) and an aromatic vinyl compound, and a structural unit derived from isoprene or a mixture of isoprene and butadiene, and a 3,4-bond A hydrogenated product of a block copolymer having a unit and a polymer block (B) having a total content of 1,2-bond units of 45% or more, and converted to standard polystyrene by gel permeation chromatography Heat containing hydrogenated block copolymer (II) having a peak top molecular weight (Mp) of 250,000 to 500,000, a polyolefin resin (III) other than (I), and a softening agent (IV) A plastic elastomer composition comprising:
Olefin rubber (I) and hydrogenated block copolymer (II) are contained in a ratio of olefin rubber (I): hydrogenated block copolymer (II) = 90: 10 to 10:90 (mass ratio). And 10 to 200 parts by mass of polyolefin resin (III) and 10 to 300 parts by mass of softener (IV) with respect to 100 parts by mass in total of olefin rubber (I) and hydrogenated block copolymer (II). A thermoplastic elastomer composition comprising a proportion of parts;
[2] The thermoplastic elastomer composition according to the above [1], wherein the polymer block (B) of the hydrogenated block copolymer (II) and the olefin rubber (I) are crosslinked.
[3] The thermoplastic elastomer composition according to the above [1], wherein the polymer block (B) of the hydrogenated block copolymer (II) comprises a structural unit derived from isoprene;
[4] The thermoplastic elastomer composition according to [1], wherein the hydrogenated block copolymer (II) has a bulk density of 0.10 to 0.40 g / ml.
[5] A molded article comprising the thermoplastic elastomer composition according to any one of [1] to [4] above;
About.

  According to the present invention, the thermoplasticity is excellent in molding processability, flexibility, vibration damping properties, compression set at high temperature and softener retention, and can obtain a molded body having a smooth surface even by extrusion molding. An elastomer composition and a molded article comprising the thermoplastic elastomer composition can be provided.

It is the schematic of the twin-screw extruder "TEM-35B" used by the Example and the comparative example.

  The thermoplastic elastomer composition of the present invention contains a predetermined amount of olefin rubber (I), specific hydrogenated block copolymer (II), polyolefin resin (III) and softener (IV). Hereinafter, each component will be described in detail.

[Olefin rubber (I)]
The olefin rubber (I) used in the present invention is a copolymer rubber of ethylene and one or more α-olefins having 3 to 20 carbon atoms (hereinafter referred to as “ethylene / α-olefin copolymer rubber”). And a cross-linked product thereof, a copolymer rubber (hereinafter referred to as “ethylene / α-olefin / non-conjugated polyene”) of ethylene and one or more of α-olefin having 3 to 20 carbon atoms and one or more of non-conjugated polyene Copolymer rubber) and cross-linked products of these, or cross-linked products of ethylene / α-olefin copolymer rubber and cross-linked products of ethylene / α-olefin / non-conjugated polyene copolymer rubber It is.
Among these, a cross-linked product of ethylene / α-olefin / non-conjugated polyene is preferable from the viewpoint of better strain recovery at high temperatures.

  Examples of the α-olefin having 3 to 20 carbon atoms constituting the olefin rubber (I) include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene. Is mentioned. These α-olefins may be used alone or in combination of two or more. Among these, propylene, 1-butene, 1-hexene and / or 1-octene are preferable, and propylene and / or 1-butene are more preferable.

  In the ethylene / α-olefin copolymer rubber, the molar ratio of ethylene to the α-olefin having 3 to 20 carbon atoms (ethylene: α-olefin having 3 to 20 carbon atoms) depends on the mechanical properties and high temperature of the thermoplastic elastomer composition. From the standpoint that the strain recovery property is maintained in a balanced manner, it is preferably in the range of 40:60 to 93: 7, more preferably in the range of 50:50 to 85:15, and 60:40 to More preferably, it is in the range of 80:20.

  Examples of the nonconjugated polyene constituting the ethylene / α-olefin / nonconjugated polyene copolymer rubber include 5-ethylidene-2-norbornene, dicyclopentadiene, 5-propylidene-2-norbornene, and 5-vinyl- Cyclic polyenes such as 2-norbornene, 2,5-norbornadiene, 1,4-cyclohexadiene, 1,4-cyclooctadiene, 1,5-cyclooctadiene; 1,4-hexadiene, 4-methyl-1,4 -Hexadiene, 5-methyl-1,4-hexadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6 -Octadiene, 5,7-dimethyl-1,6-octadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,7 Nonadiene, 8-methyl-1,8-decadiene, 9-methyl-1,8-decadiene, 4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6-octadiene, 7-methyl- 4-ethylidene-1,6-nonadiene, 7-ethyl-4-ethylidene-1,6-nonadiene, 6,7-dimethyl-4-ethylidene-1,6-octadiene, 6,7-dimethyl-4-ethylidene- A chain polyene having an internal unsaturated bond having 6 to 15 carbon atoms such as 1,6-nonadiene; 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1, Examples include α, ω-dienes such as 9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, 1,13-tetradecadiene, and the like.

  Among them, one of 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, 7-methyl-1,6-octadiene and 5-methyl-1,4-hexadiene is preferable, From the viewpoint of excellent reactivity, at least one of 5-ethylidene-2-norbornene, dicyclopentadiene and 5-vinyl-2-norbornene is more preferable.

  In the ethylene / α-olefin / non-conjugated polyene copolymer rubber, the molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene: α-olefin having 3 to 20 carbon atoms) is 90:10 to 40:60. In particular, 80:20 to 50:50 is preferable because flexibility and rubber elasticity of the resulting thermoplastic elastomer composition are improved.

  The mechanical strength of the thermoplastic elastomer composition is such that the iodine value (iodine value before crosslinking) of the ethylene / α-olefin / non-conjugated polyene copolymer rubber is in the range of 3 to 40, particularly 5 to 25. Further, it is preferable because rubber elasticity is improved. When an ethylene / α-olefin / non-conjugated polyene copolymer rubber having an iodine value lower than 3 is used, the molded product obtained from the thermoplastic elastomer composition tends to be inferior in mechanical strength. If the higher ethylene / α-olefin / non-conjugated polyene copolymer rubber is used, the rubber elasticity of the thermoplastic elastomer composition tends to be impaired. In addition, the "iodine value" as used in this specification means the iodine value measured by the method described in JIS K1525 4.7.

The olefin rubber (I) preferably has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 25 to 350, and preferably 40 to 300 because the molding processability of the thermoplastic elastomer composition is good. And the mechanical strength of the molded product obtained from the composition is high.
As used herein, “Mooney viscosity (ML _{1 + 4} , 100 ° C.)” refers to a viscosity measured by the method described in JIS K6300.

  The olefin rubber (I) may be previously crosslinked, and the degree of crosslinking can be appropriately adjusted according to the use of the composition of the present invention. When I) was subjected to Soxhlet extraction treatment with cyclohexane for 10 hours, the mass ratio (gel fraction) of the gel remaining without being dissolved in cyclohexane was 80 with respect to the mass of the olefin rubber after crosslinking before the extraction treatment. It is preferable that the degree of cross-linking is not less than 95%, particularly not less than 95%, since the thermoplastic elastomer composition of the present invention and the molded article comprising the composition have better strain recovery at high temperatures.

[Hydrogenated block copolymer (II)]
The hydrogenated block copolymer (II) used in the present invention comprises a polymer block (A) composed of a structural unit derived from an aromatic vinyl compound and a structural unit derived from isoprene or a mixture of isoprene and butadiene. , 4-bond unit and 1,2-bond unit sum of the content and the polymer block (B) having a content of 45% or more, which is obtained by gel permeation chromatography The peak top molecular weight (Mp) determined in terms of standard polystyrene is 250,000 to 500,000.
In this specification, the 3,4-bond unit in the structural unit derived from isoprene and the 1,2-bond unit in the structural unit derived from butadiene are referred to as “vinyl bond unit”, and the total amount thereof is referred to as “vinyl bond unit”. Referred to as "content".

  The polymer block (A) of the hydrogenated block copolymer (II) 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 90% by mass or more, more preferably 95% by mass or more, and further preferably 100% by mass based on the mass of the polymer block (A). Means that.

  Examples of the aromatic vinyl compound constituting the polymer block (A) include styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, Examples include 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, vinylnaphthalene, and vinylanthracene. 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. Especially, it is preferable that a polymer block (A) is mainly comprised from the structural unit derived from styrene.

  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 proportion of the structural unit derived from the other copolymerizable monomer is preferably less than 10% by mass based on the mass of the polymer block (A), and more preferably less than 5% by mass. preferable. Examples of other copolymerizable monomers include ion polymerizable monomers such as 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether. The bonding form of 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 (II) mainly contains structural units derived from isoprene alone or a mixture of isoprene and butadiene. The term “mainly” as used herein means that the structural unit derived from isoprene alone or a mixture of isoprene and butadiene is preferably 70% by mass or more, more preferably 90% by mass, based on the mass of the polymer block (B). That means that. In the case of butadiene alone, even if the content of 1,2-bond units is increased, visual transparency, vibration damping properties, fluidity, and improvement in compression set at high temperatures are poor, and practical significance. There are few.

When the polymer block (B) is composed only of a structural unit derived from isoprene, the structural unit is a 2-methyl-2-butene-1,4-diyl group [—CH ₂ —C (CH ₃ ) ═CH—. CH ₂ -; 1,4-bond unit, isopropenyl ethylene group _{[-CH (C (CH 3)} = CH 2) -CH 2 -; 3,4- bond unit] and 1-methyl-1-vinyl ethylene It consists of a group [—C (CH ₃ ) (CH═CH ₂ ) —CH ₂ —; 1,2-bond unit], and in the present invention, the vinyl bond content is 45% or more. The vinyl bond content is more preferably 47% or more, and further preferably 50% or more. Although there is no restriction | limiting in particular in the upper limit of vinyl bond content, Usually, it is 95% or less, and it is more preferable that it is 90% or less.

When the polymer block (B) is composed of a structural unit derived from a mixture of isoprene and butadiene, the structural unit is a 2-methyl-2-butene-1,4-diyl group or isopropenyl derived from isoprene. Ethylene group and 1-methyl-1-vinylethylene group, and 2-butene-1,4-diyl group derived from butadiene [—CH ₂ —CH═CH—CH ₂ —; 1,4-bond unit] and vinyl It consists of an ethylene group [—CH (CH═CH) —CH ₂ —; 1,2-bond unit] and has a vinyl bond content of 45% or more. The vinyl bond content is more preferably 47% or more, and further preferably 50% or more. Although there is no restriction | limiting in particular in the upper limit of vinyl bond content, Usually, it is 95% or less, and it is more preferable that it is 90% or less. In the copolymer block, the arrangement of the structural unit derived from isoprene and the structural unit derived from butadiene may be random, block, or tapered.

  In the case where the polymer block (B) is composed of a structural unit derived from a mixture of isoprene and butadiene, from the viewpoint of maintaining good vibration damping and fluidity of the thermoplastic elastomer composition obtained in the present invention, isoprene units / butadiene Unit (molar ratio) is preferably 10/90 to 99/1, more preferably 30/70 to 99/1, and still more preferably 40/60 to 99/1.

  The polymer block (B) has a small amount of structural units derived from other copolymerizable monomers together with structural units derived from isoprene or isoprene and butadiene within the range not impairing the object of the present invention. May be. 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 may be used alone or in combination of two or more. When the polymer block (B) has a structural unit derived from another copolymerizable monomer such as an aromatic vinyl compound in addition to the structural unit derived from isoprene or isoprene and butadiene, the bonding form thereof is random, Any of tapered shapes may be used.

The hydrogenated block copolymer (II) used in the present invention has a part of unsaturated double bonds (carbon-carbon double bonds) in the polymer block (B) from the viewpoint of good heat resistance. Or it is preferable that all are hydrogenated. The hydrogenation rate of the polymer block (B) at that time is preferably 50 mol% or more, more preferably 60 mol% or more, and further preferably 70 mol% or more.
In addition, the hydrogenation rate of the unsaturated double bond in the polymer block (B) is described in the examples described later before and after the hydrogenation of the content of the unsaturated double bond in the polymer block (B). It can be obtained from the iodine value measurement.

  The hydrogenated block copolymer (II) is a functional group such as a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, and an epoxy group in the molecular chain and / or at the molecular end within a range not impairing the effects of the present invention. 1 type (s) or 2 or more types may be included.

The hydrogenated block copolymer (II) is a hydrogenated product of a block copolymer containing at least one polymer block (A) and each polymer block (B). Preferably, the hydrogenated block copolymer (II) is a hydrogenated product of a block copolymer containing two or more polymer blocks (A) and one or more polymer blocks (B). 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. However, when the polymer block (A) is represented by A and the polymer block (B) is represented by B, (A-B) l, A- (B-A) m, B- (A-B) n (wherein l, m and n each independently represents an integer of 1 or more) is preferably a bonded form, and viewpoints such as rubber elasticity, mechanical properties and handleability From the above, it is particularly preferable to be a bonded form of a diblock structure represented by AB or a triblock structure represented by ABA.
In the case where the hydrogenated block copolymer (II) has two or more polymer blocks (A) or two or more polymer blocks (B), the respective polymer blocks (A) and the respective polymer blocks (A) The combined block (B) may be a block having the same configuration or a block having a different configuration. For example, in the two polymer blocks (A) in the triblock structure represented by [ABA], the types of the aromatic vinyl compounds constituting them may be the same or different. Good.

The content of the polymer block (A) is preferably in the range of 5 to 70% by mass and more preferably in the range of 15 to 50% by mass with respect to the hydrogenated block copolymer (II). When the content of the polymer block (A) is in the above range, the resulting thermoplastic elastomer composition is excellent in rubber elasticity and flexibility. The content of the polymer block in the hydrogenated block copolymer (II) (A) can be determined by ¹ H-NMR spectrum.

In the hydrogenated block copolymer (II), the peak top molecular weight of the polymer block (A) is preferably 10,000 to 60,000, more preferably 15,000 to 45,000. The peak top molecular weight of the polymer block (B) is preferably 130,000 to 450,000, more preferably 180,000 to 430,000 in the state before hydrogenation.
Moreover, the peak top molecular weight (Mp) of the whole hydrogenated block copolymer (II) is 250,000-500,000 in the state after hydrogenation, and it is more preferable that it is 310,000-500,000. preferable. When the Mp of the hydrogenated block copolymer (a) is within the above range, a powdered hydrogenated block copolymer (II) having a bulk density in the range of 0.10 to 0.40 g / ml can be easily obtained. It is done. In addition, Mp as used in this specification is the value calculated | required in standard polystyrene conversion by the gel permeation chromatography (GPC) method.

  The hydrogenated block copolymer (II) is a powder having a bulk density of 0.10 to 0.40 g / ml from the viewpoint of excellent absorbability of the softening agent (IV) described later and excellent compression set at high temperature. It is preferable that the powder is 0.15 to 0.35 g / ml. When the bulk density is less than 0.10 g / ml, the handleability may be deteriorated, and when it exceeds 0.40 g / ml, the absorbability of the softening agent (IV) may be deteriorated. The bulk density as used herein is a value calculated by putting the weighed powdered hydrogenated block polymer (II) into a graduated cylinder, measuring its volume, and dividing the mass of the polymer by the volume. It is.

<Production of hydrogenated block copolymer (II)>
Examples of the method for producing the hydrogenated block copolymer (II) include polymerization methods such as ion polymerization methods such as anionic polymerization and cationic polymerization, single site polymerization methods, and radical polymerization methods. In the case of the anionic polymerization method, for example, an aromatic vinyl compound, a conjugated diene compound (isoprene, or isoprene and butadiene is used in an inert organic solvent such as n-hexane or cyclohexane using an alkyl lithium compound as a polymerization initiator. A block copolymer having a desired molecular structure and molecular weight, and then adding an active hydrogen compound such as alcohols, carboxylic acids and water to stop the polymerization. Coalescence can be produced. The hydrogenated block copolymer (II) can be obtained by conducting a hydrogenation reaction in the presence of a hydrogenation catalyst in an inert organic solvent without preferably isolating the obtained block copolymer. it can.

  Examples of the alkyl lithium compound include alkyl lithium compounds having 1 to 10 carbon atoms in the alkyl residue, and methyl lithium, ethyl lithium, butyl lithium, and pentyl lithium are particularly preferable. The amount of the initiator such as an alkyl lithium compound is appropriately determined depending on the Mp of the hydrogenated block copolymer (II), but is generally an initiator with respect to 100 parts by mass of all monomers used for the polymerization. It is used in the range of 0.01 to 0.2 parts by mass. The polymerization is usually carried out in the temperature range of 0 to 80 ° C. for 0.5 to 50 hours.

  In the polymer block (B) of the hydrogenated block copolymer (II), the structural unit composed of isoprene or a mixture of isoprene and butadiene has a vinyl bond content of 45% or more. Lewis base is used as a cocatalyst. Examples of the Lewis base include ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran; glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; triethylamine, N, N, N ′, N′-tetramethylenediamine, N-methylmorpholine, and the like. These amine compounds can be mentioned. The amount of these Lewis bases used is generally in the range of 0.1 to 1000 times the number of moles of lithium of the alkyl lithium compound used as the initiator.

  In the hydrogenation reaction, an unhydrogenated block copolymer is dissolved in an inert organic solvent such as n-hexane or cyclohexane which is inert to the reaction and the hydrogenation catalyst in the presence of a hydrogenation catalyst. Thus, a method of reacting molecular hydrogen is preferably used. In addition, it is also possible to subject the reaction liquid obtained by sequentially copolymerizing an aromatic vinyl compound and isoprene (or a mixture of isoprene and butadiene) to a hydrogenation reaction as it is. Examples of hydrogenation catalysts include Raney nickel; heterogeneous catalysts such as Pt, Pd, Ru, Rh, Ni and other metals supported on carbon, alumina, diatomaceous earth, etc .; transition metal compounds and alkylaluminum compounds, alkyllithiums A Ziegler-based catalyst composed of a combination of compounds is used. The reaction is usually carried out at a hydrogen pressure of 0.1 to 20 MPa, a reaction temperature of 20 ° C. to 250 ° C., and a reaction time of 0.1 to 100 hours.

  The powdered hydrogenated block copolymer (II) having a bulk density of 0.10 to 0.40 g / ml used in the present invention can be produced, for example, by the following method. The reaction solution from which the hydrogenation catalyst has been removed by filtration after the above hydrogenation reaction is heated to 40 to 150 ° C., preferably 60 to 150 ° C., and a surfactant such as a fatty acid salt or a polyoxyalkylene derivative is mixed as necessary. In this state, it is supplied into hot water at 80 to 130 ° C. at a rate of 100 parts by mass / hour, and at the same time, 1 MPa of steam is supplied at a rate of 40 to 60 parts by mass / hour to inactivate saturated hydrocarbons and the like. When the boiling point of the organic solvent or the inert organic solvent and water is azeotroped, steam stripping is performed at a temperature not lower than the azeotropic temperature and not higher than 150 ° C., and the moisture content is 55 mass% / WB (wet) with a compressed water squeezer Base, the same shall apply hereinafter), preferably 45% by mass / WB or less, using a screw extruder dryer, expander dryer, conduction heat transfer dryer, hot air dryer, etc. By drying at 0 to 100 ° C., water content 0.1 wt% / WB less desired powder hydrogenated block copolymer of (II) can be produced.

The thermoplastic elastomer composition of the present invention comprises olefin rubber (I) and hydrogenated block copolymer (II), olefin rubber (I): hydrogenated block copolymer (II) (mass ratio) = 90. : From 10 to 10:90, especially from 80:20 to 20:80 is excellent in molding processability and flexibility, from the point of excellent strain recovery after applying strain for a long time at high temperature preferable.
In the thermoplastic elastomer composition of the present invention, the olefinic rubber (I) and the hydrogenated block copolymer (II) are converted into olefinic rubber (I): hydrogenated block copolymer (II) (mass ratio) = 90. : 10 to 50:50, preferably 80:20 to 60:40, a thermoplastic elastomer composition and a molded article excellent in molding processability, flexibility, and strain recovery after being strained for a long time at high temperature Can be obtained at a more economical cost.

[Polyolefin resin (III)]
The polyolefin-based resin (III) used in the present invention refers to a known polyolefin-based resin other than the above-described olefin-based rubber (I). For example, an ethylene-based polymer, a propylene-based polymer, polybutene-1 and poly-4-methyl Penten-1 etc. can be mentioned, These 1 type (s) or 2 or more types can be used preferably. Among these, from the viewpoint of excellent molding processability, one or both of an ethylene polymer and a propylene polymer are preferable, and a propylene copolymer is more preferable.

Examples of the ethylene polymer include ethylene homopolymers such as high density polyethylene, medium density polyethylene, and low density polyethylene, ethylene / butene-1 copolymer, ethylene / hexene copolymer, ethylene / heptene copolymer, Ethylene / octene copolymer, ethylene / 4-methylpentene-1 copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ethylene / methacrylic acid copolymer And ethylene copolymers such as ethylene / methacrylic acid ester copolymers, and one or more of these may be used. Among these, one or more of high density polyethylene, medium density polyethylene and low density polyethylene is preferably used.
Examples of the propylene polymer include propylene homopolymer, ethylene / propylene random copolymer, ethylene / propylene block copolymer, propylene / butene-1 copolymer, propylene / ethylene / butene-1 copolymer, propylene. -4-methylpentene-1 copolymer etc. are mentioned, These 1 type (s) or 2 or more types can be used. Among these, one or more of propylene homopolymer, ethylene / propylene random copolymer and ethylene / propylene block copolymer are more preferably used from the viewpoint of moldability.

[Softener (IV)]
Examples of the softener (IV) used in the present invention include paraffinic, naphthenic, and aromatic process oils; phthalic acid derivatives such as dioctyl phthalate and dibutyl phthalate; white oil; mineral oil; ethylene and α-olefin Liquid co-oligomer; liquid paraffin; polybutene; low molecular weight polyisobutylene; liquid polybutadiene such as liquid polybutadiene, liquid polyisoprene, liquid polyisoprene / butadiene copolymer, liquid styrene / butadiene copolymer, liquid styrene / isoprene copolymer, and Examples of such hydrogenated products. Among these, from the viewpoint of compatibility with the hydrogenated block copolymer (II), paraffinic process oil; liquid co-oligomer of ethylene and α-olefin; and liquid paraffin are preferable.

  Among the softeners (IV), the paraffinic oil has a kinematic viscosity at 40 ° C. of 20 to 800 cst (centistokes), particularly 50 to 600 cst, and a pour point of −40 to 0 ° C., particularly −30 to 0. Those having a C and a flash point (COC method) of 200 to 400 ° C., particularly 250 to 350 ° C. are preferably used.

  The thermoplastic elastomer composition of the present invention is characterized in that it contains a specific amount of the above-mentioned olefin rubber (I), hydrogenated block copolymer (II), polyolefin resin (III) and softener (IV). Specifically, the olefin rubber (I) and the hydrogenated block copolymer (II) are converted into olefin rubber (I): hydrogenated block copolymer (II) = 90: 10 to 10:90 (mass ratio). ) And a total of 100 parts by mass of the olefin rubber (I) and the hydrogenated block copolymer (II), 10 to 200 parts by mass of a polyolefin resin (III) and a softener (IV ) In a ratio of 10 to 300 parts by mass.

The thermoplastic elastomer composition of the present invention is a proportion of 10 to 200 parts by mass of the polyolefin resin (III) with respect to 100 parts by mass in total of the olefin rubber (I) and the hydrogenated block copolymer (II). It is necessary to contain. By containing 10 to 200 parts by mass of the polyolefin resin (III), the polyolefin resin (III) forms a continuous phase in the thermoplastic elastomer composition, and the olefin rubber ( I) and a hydrogenated block copolymer (II) crosslinked at least in the polymer block (A) part have a dispersed morphology in fine particles, strain recovery at high temperature, flexible rubber-like Properties and good moldability are imparted to the thermoplastic elastomer composition.
The thermoplastic elastomer composition obtained when the content of the polyolefin resin (III) is less than 10 parts by mass with respect to a total of 100 parts by mass of the olefin rubber (I) and the hydrogenated block copolymer (II). The thermoplasticity of the resin becomes insufficient, and the molding processability is inferior. On the other hand, when it exceeds 200 mass parts, the flexibility of the obtained thermoplastic elastomer composition is insufficient. The thermoplastic elastomer composition of the present invention is a total of the olefinic rubber (I) and the hydrogenated block copolymer (II) from the viewpoint that the molding processability and flexibility of the thermoplastic elastomer composition and the molded body become better. It is preferable to contain polyolefin-type resin (III) in the ratio of 12-150 mass parts with respect to 100 mass parts, and it is more preferable to contain in the ratio of 14-100 mass parts.

  The thermoplastic elastomer composition of the present invention contains the softener (IV) in a proportion of 10 to 300 parts by mass with respect to 100 parts by mass in total of the olefinic rubber (I) and the hydrogenated block copolymer (II). Olefinic rubber (I) from the viewpoints that the thermoplastic elastomer composition and the molded article comprising the thermoplastic elastomer composition have good moldability, flexibility, and high strain recovery and oil resistance at high temperatures. The softening agent (IV) is preferably contained in a proportion of 50 to 250 parts by mass with respect to a total of 100 parts by mass of the hydrogenated block copolymer (II) and contained in a proportion of 60 to 200 parts by mass. More preferably. When the content of the softening agent (IV) is more than 300 parts by mass, the thermoplastic elastomer composition and the molded article comprising the same cause bleed out of the softening agent (IV), lowering oil resistance and mechanical properties, and 10 parts by mass. If it is less than the range, flexibility and moldability are inferior.

  When the olefin rubber (I) used in the present invention and the polymer block (B) of the hydrogenated block copolymer (II) are crosslinked, a crosslinking agent (V), a crosslinking assistant (VI) and a crosslinking accelerator ( VII) can be used as needed.

[Crosslinking agent (V)]
Examples of the crosslinking agent (V) include a radical generator, sulfur or a sulfur compound.
Examples of the radical generator include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t- Butylperoxy) hexyne-3,1,3-bis (t-butylperoxyisopropyl) benzene, α, α′-bis (t-butylperoxy) diisopropylbenzene, 3,3,5-trimethylcyclohexane, n-butyl-4 , 4-bis (t-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, t- Butylcumylpe And organic peroxides such as oxides, which may be alone or in combination of two or more, one kind. Among these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and dicumyl peroxide are preferably used from the viewpoint of reactivity.
When these radical generators are used, 0.01 to 15 parts by mass, preferably 0.05 to 10 parts by mass with respect to 100 parts by mass in total of the olefin rubber (I) and the hydrogenated block copolymer (II). Used within the scope of parts.

  Examples of the sulfur compound include sulfur monochloride and sulfur dichloride. When sulfur or a sulfur compound is used, the addition amount is 0.1 to 20 parts by mass, preferably 0.2 to 100 parts by mass in total of the olefinic rubber (I) and the hydrogenated block copolymer (II). -10 parts by mass.

  Other cross-linking agents (V) include phenolic resins such as alkylphenol resins and brominated alkylphenol resins; combinations of p-quinonedioxime and lead dioxide, p, p'-dibenzoylquinonedioxime and trilead tetroxide, etc. Can also be used.

[Crosslinking aid (VI)]
Examples of the crosslinking aid (VI) include polyfunctional monomers such as triallyl isocyanurate, divinylbenzene, ethylene glycol dimethacrylate, and triethylene glycol dimethacrylate; stannous chloride, ferric chloride, organic sulfonic acid , Polychloroprene and chlorosulfonated polyethylene.

[Crosslinking accelerator (VII)]
Examples of the crosslinking accelerator (VII) include thiazoles such as N, N-diisopropyl-2-benzothiazole-sulfenamide, 2-mercaptobenzothiazole, 2- (4-morpholinodithio) benzothiazole; diphenylguanidine, Guanidines such as triphenylguanidine; aldehyde-amine or aldehyde-ammonia reactants such as butyraldehyde-aniline reactant, hexamethylenetetramine-acetaldehyde reactant; imidazolines such as 2-mercaptoimidazoline; thiocarbanilide, diethyl Thioureas such as urea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, pentamethyle Thiuram mono- or polysulfides such as thiuram tetrasulfide; Thiocarbamates such as zinc dimethyldithiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate; xanthogens such as zinc dibutylxanthate Acid salts; zinc white and the like. These crosslinking accelerators (VII) may be used alone or in combination of two or more.

[About crosslinking method]
In the thermoplastic elastomer composition of the present invention, the polymer block (B) portion of the olefin rubber (I) and the hydrogenated block copolymer (II) may be crosslinked by the following method.
As a crosslinking method, a method in which a crosslinking agent (V), a crosslinking assistant (VI) and a crosslinking accelerator (VII) are appropriately added to the olefin rubber (I) and the hydrogenated block copolymer (II) and kneaded. (Method 1), resin crosslinking method (Method 2), quinoid crosslinking method (Method 3), a method using active energy rays (Method 4), and the like.

<About Method 1>
In the thermoplastic elastomer composition of the present invention, a crosslinking agent (V), a crosslinking assistant (VI) and a crosslinking accelerator (VII) are appropriately added to the olefin rubber (I) and the hydrogenated block copolymer (II). Then, the polymer block (B) of the olefin rubber (I) and the hydrogenated block copolymer (II) can be easily crosslinked by kneading.
For example, cross-linking aids such as polyfunctional monomers such as triallyl isocyanurate, divinylbenzene, ethylene glycol dimethacrylate, and triethylene glycol dimethacrylate, if necessary, along with a crosslinking agent (V) such as an organic peroxide. Crosslinking accelerators (VII) such as disulfide compounds such as agent (VI), benzothiazyl disulfide, and tetramethylthiuram disulfide may be used. When the crosslinking aid (VI) and the crosslinking accelerator (VII) are used, the addition amount is about 0. 0 parts per 100 parts by mass in total of the olefin rubber (I) and the hydrogenated block copolymer (II). 1 to 20 parts by mass, preferably 0.2 to 10 parts by mass.
In the case of crosslinking by such a method, for example, a method of melt-kneading the thermoplastic elastomer composition, a radical generator and, if necessary, another thermoplastic resin under heating can be mentioned. The heating temperature is preferably 140 to 230 ° C., and the melt-kneading can be performed batchwise or continuously in an apparatus such as an extruder, a kneader, a roll, or a plastograph. The crosslinking reaction proceeds by such a melt-kneading process.

When sulfur or a sulfur compound is used as the crosslinking agent (V), crosslinking accelerators such as thiazoles, guanidines, butyraldehyde-aniline reactants, hexamethylenetetramine-acetaldehyde reactants, aldehyde-amine reactants ( It is highly preferred to use VII) together.
When performing crosslinking by such a method, the crosslinking agent (V), the crosslinking accelerator (VII) and the like are preferably used in a range of 50 to 250 ° C., more preferably 80 to 200 ° C. using a mixer such as a roll or a Banbury mixer. After kneading in the range, preferably 60 ° C. or higher, more preferably in the range of 90 to 250 ° C., usually for 1 minute to 2 hours, more preferably 5 minutes to 1 hour to form a crosslink. In addition, when using together crosslinking accelerator (VII), the addition amount is preferably 0.05-30 mass with respect to 100 mass parts of olefin rubber (I) and hydrogenated block copolymer (II) total. Part, more preferably 0.1 to 20 parts by weight, still more preferably 0.2 to 10 parts by weight.

<About Method 2>
In the crosslinking method based on resin crosslinking, phenolic resins such as alkylphenol resins and brominated alkylphenol resins are used as the crosslinking agent (V), and stannous chloride, ferric chloride, organic sulfonic acid, poly (polysiloxane) as the crosslinking aid (VI). Chloroprene, chlorosulfonated polyethylene or the like is used.
When performing crosslinking by such a method, the addition amount of the phenol resin as the crosslinking agent (V) is 1 to 30 parts by mass with respect to 100 parts by mass in total of the olefin rubber (I) and the hydrogenated block copolymer (II). The range of 5-20 mass parts is more preferable. The amount of the crosslinking aid (VI) added is preferably in the range of 0.1 to 10 parts by mass, and more preferably in the range of 0.5 to 5 parts by mass. The crosslinking temperature is preferably in the range of 100 to 250 ° C, more preferably 130 to 220 ° C. When resin crosslinking is performed, it is extremely preferable to use a crosslinking accelerator (VII) in combination.

<About Method 3>
In the crosslinking method using quinoid crosslinking, a combination of p-quinonedioxime and lead dioxide, p, p'-dibenzoylquinonedioxime and trilead tetroxide, or the like is used as the crosslinking agent (V).
When performing crosslinking by such a method, the quinone oxime is preferably 0.1 to 10 parts by mass, more preferably 0 to 100 parts by mass in total of the olefinic rubber (I) and the hydrogenated block copolymer (II). It is added in the range of 0.5 to 5 parts by mass, and lead oxides are preferably added in the range of 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass. The crosslinking temperature is preferably in the range of 90 to 250 ° C, more preferably 110 to 220 ° C. When performing quinoid crosslinking, it is preferable to use a crosslinking accelerator (VII) in combination.

[Other ingredients]
The thermoplastic elastomer composition of the present invention can contain other thermoplastic polymers as long as the effects of the present invention are not impaired. Other thermoplastic polymers include, for example, polyphenylene ether resins; polyamide 6, polyamide 6 · 6, polyamide 6 · 10, polyamide 11, polyamide 12, polyamide 6 · 12, polyhexamethylenediamine terephthalamide, polyhexamethylenediamine Polyamide resins such as isophthalamide and xylene group-containing polyamide; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Acrylic resins such as polymethyl acrylate and polymethyl methacrylate; Polyoxymethylene homopolymers and polyoxymethylene copolymers Polyoxymethylene resins such as: Styrene homopolymers, styrene resins such as acrylonitrile-styrene resins, acrylonitrile-butadiene-styrene resins; Nate resin; Styrenic elastomer such as styrene / butadiene copolymer rubber and styrene / isoprene copolymer rubber and hydrogenated product or modified product thereof; Natural rubber; Liquid polyisoprene rubber and hydrogenated product or modified product thereof; Chloroprene Examples include rubber, acrylic rubber, acrylonitrile butadiene rubber, epichlorohydrin rubber, silicone rubber, chlorosulfonated polyethylene, urethane rubber, polyurethane elastomer, polyamide elastomer, polyester elastomer, and soft vinyl chloride resin.
The content of the other thermoplastic polymer may be used as long as the flexibility and mechanical properties of the thermoplastic elastomer composition are not impaired, and the thermoplastic elastomer composition before addition of the other thermoplastic polymer is used. It is preferable that it is 200 mass parts or less with respect to 100 mass parts.

  The thermoplastic elastomer composition of the present invention may further contain various additives as long as the effects of the present invention are not impaired. Examples of such additives include lubricants, antioxidants, heat stabilizers, light stabilizers, weathering agents, metal deactivators, ultraviolet absorbers, light stabilizers, copper damage inhibitors, fillers, reinforcing agents, and antistatic agents. , Antibacterial agents, fungicides, dispersants, colorants and the like.

Among them, the lubricant has an action of improving the fluidity of the thermoplastic elastomer composition of the present invention and suppressing thermal degradation. Examples of the lubricant used in the present invention include silicone oils; hydrocarbon lubricants such as paraffin wax, microwax and polyethylene wax; butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, stearyl stearate and the like.
Examples of the filler include calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, magnesium carbonate, glass fiber, and carbon fiber.

The method for producing the thermoplastic elastomer composition of the present invention is not particularly limited. For example, when producing a thermoplastic elastomer composition comprising olefin rubber (I), hydrogenated block copolymer (II), polyolefin resin (III) and softener (IV) in specific proportions, A mixture of an olefin rubber (I), a polyolefin resin (III), and a softening agent (IV) obtained by crosslinking the olefin rubber (I) in advance is prepared, and a hydrogenated block copolymer (II) and a polyolefin system are prepared therein. A method in which a mixture of resin (III) and softening agent (IV) is further added and melt-mixed can be mentioned.
Further, after mixing the olefin rubber (I), polyolefin resin (III), softener (IV) and crosslinking agent (V) as necessary, the hydrogenated block copolymer (II) or hydrogenated block copolymer is mixed. A method in which the polymer (II) and the softening agent (IV) are added and the mixture is dynamically cross-linked under the melting condition is preferable from the viewpoint that the respective components can be uniformly mixed simultaneously with the cross-linking of the olefin rubber (I). .
Here, “dynamically cross-linking under melting conditions” in the present specification means cross-linking while applying shear stress to the mixture in a molten state by kneading.

As a device for performing dynamic crosslinking for producing the thermoplastic elastomer composition of the present invention, any of melt-kneading devices capable of uniformly mixing each component can be used, for example, a single screw extruder, a twin screw extruder, or the like. Machine, kneader, Banbury mixer, etc. Among them, it is preferable to use a twin screw extruder that has a large shearing force during kneading and can be operated continuously.

  The following method is mentioned as a specific example of the process at the time of manufacturing a thermoplastic elastomer composition using an extruder. That is, olefin rubber (I), hydrogenated block copolymer (II), polyolefin resin (III), softener (IV) and the like are mixed and charged into a hopper of an extruder. In that case, polyolefin resin (III), softening agent (IV), crosslinking agent (V), crosslinking assistant (VI) and crosslinking accelerator (VII) are added to olefin rubber (I) and hydrogenated block copolymer. Add to (II) from the beginning, or add part or all of them from the middle of the extruder and melt knead and extrude. In that case, you may melt-knead sequentially in steps using two or more extruders. The melt kneading temperature may be appropriately selected within a range in which the olefin rubber (I), the hydrogenated block copolymer (II), and the polyolefin resin (III) melt and the crosslinking agent (V) reacts. It is preferable that it is 160 to 270 degreeC, and it is more preferable that it is 180 to 240 degreeC. The melt kneading time is preferably about 30 seconds to 5 minutes.

  The thermoplastic elastomer composition of the present invention obtained as described above can be obtained by molding using a method such as injection molding, extrusion molding or subsequent blow molding.

  The thermoplastic elastomer composition of the present invention is excellent in molding processability, flexibility, vibration damping properties, compression set at high temperatures, and softener retention, so that sheets, films, plates, tubes, hoses, It can be used for various molded products such as belts. For example, anti-vibration rubber, mats, seats, cushions, dampers, pads, mount rubber and other anti-vibration / vibration components; footwear for sports shoes, fashion sandals, etc .; household appliances such as TVs, stereos, vacuum cleaners and refrigerators Applications: Building materials such as sealing packing used for building doors and window frames; Automotive interior / exterior components such as bumper parts, body panels, weather strips, grommets, instrument panels, and airbag covers; scissors, Various grips in drivers, toothbrushes, ski stocks, etc .; food packaging materials such as food wrap films; protective films; medical devices such as infusion bags, syringes, and catheters; stoppers for containers for storing food, beverages, drugs, etc. It can be used effectively in a wide range of applications such as cap liners. Kill.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In addition, the physical-property evaluation in a manufacture example, an Example, and a comparative example was performed by the method shown below.

(1) Content of polymer block (A) The block copolymer (II) after hydrogenation was dissolved in CDCl ₃ and ¹ H-NMR spectrum was measured (apparatus: JNM-Lambda 500 (JEOL Ltd.) And the content of the polymer block (A) was calculated from the peak intensity derived from styrene.

(2) Peak top molecular weight (Mp)
By the gel permeation chromatography (GPC) measurement, the peak top molecular weight (Mp) in terms of polystyrene was determined for the polymer block (A) before hydrogenation and the hydrogenated block copolymer (II) after hydrogenation.
Equipment: Gel permeation chromatograph “HLC-8020” manufactured by Tosoh Corporation
Column: G4000HXL x 2 (Tosoh Corporation)
Eluent: Tetrohydrofuran, flow rate: 1 ml / min Injection volume: 150 μl
Concentration: 5 mg / 10 ml (block copolymer / tetrohydrofuran),
Column temperature: 40 ° C
Calibration curve: Prepared using standard polystyrene Detection method: Differential refractive index (RI)

(3) Hydrogenation rate of hydrogenated block copolymer (II) The iodine value of the block copolymer before and after hydrogenation was measured, and the hydrogenation rate (% of hydrogenated block copolymer (II) was determined from the measured value. ) Was calculated.
Hydrogenation rate (%) = {1− (iodine value of block copolymer after hydrogenation / iodine value of block copolymer before hydrogenation)} × 100

(4) Vinyl bond content of polymer block (B) of hydrogenated block copolymer (II) The block copolymer before hydrogenation was dissolved in CDCl ₃ and ¹ H-NMR spectrum was measured (apparatus: JNM -Lambda 500 (manufactured by JEOL Ltd., measurement temperature: 50 ° C.), and the total peak area of structural units derived from isoprene, butadiene, or a mixture of isoprene and butadiene, 3,4-bond units in isoprene structural units, and In the case of a 1,2-bond unit, a 1,2-bond unit in a butadiene structural unit, or a mixture of isoprene and butadiene, the vinyl bond content (3,4- The sum of the content of bond units and 1,2-bond units) was calculated.

(5) Hardness Using pellets of the thermoplastic elastomer composition obtained in the following examples and comparative examples, injection molding was performed at 200 ° C. with an injection molding machine (“IS-55EPN”, manufactured by Toshiba Machine Co., Ltd.). A sheet-like test piece having a length of 110 mm, a width of 110 mm, and a thickness of 2 mm was prepared, and three sheets of the injection-molded sheets were stacked in accordance with JIS K 6253, and the hardness of a thickness of 6 mm was measured. The hardness meter used was a type A durometer, and the measured value was recorded as an instantaneous value. When the type A hardness is preferably 95 or less, more preferably 90 or less, and still more preferably 85 or less, the obtained molded article is excellent in flexibility.

(6) Rebound resilience (damping property)
The pellets of the thermoplastic elastomer composition obtained in the following examples and comparative examples were compression-molded at 200 ° C. for 3 minutes by a compression molding machine, diameter 29.0 ± 0.5 mm, thickness 12.5 ± A 0.5 mm cylindrical test piece was prepared. Using this test piece, the rebound resilience at 25 ° C. was measured with a Lüpke-type rebound resilience tester in accordance with JIS K 6255. The smaller the value of the impact resilience, the better the vibration damping. The rebound resilience is preferably 60% or less, more preferably 55% or less, and still more preferably 53 or less. When the rebound resilience is within the above range, the obtained molded article is excellent in vibration damping properties.

(7) Compression set Using the thermoplastic elastomer composition pellets obtained in the following examples and comparative examples, compression molding was performed at 200 ° C. for 3 minutes using a compression molding machine, and the diameter was 13.0 ± 0.5 mm. A columnar test piece having a thickness of 6.3 ± 0.3 mm was produced. Using this cylindrical test piece, the compression set after maintaining 25% compression deformation for 22 hours at two temperatures of 70 ° C. and 120 ° C. was measured in accordance with JIS K 6262. The smaller this value, the better the compression set at a high temperature. Preferably, it is 55% or less under both conditions of 70 ° C. and 120 ° C., more preferably 50% or less under both conditions of 70 ° C., 100 ° C., and 120 ° C. % Or less. When the compression set is within the above range, the obtained molded article is excellent in compression set at a high temperature.

(8) Retaining property of softener Using pellets of the thermoplastic elastomer composition obtained in the following examples and comparative examples, the injection molding machine (“IS-55EPN”, manufactured by Toshiba Machine Co., Ltd.) at 200 ° C. After injection molding, a sheet-like test piece having a length of 110 mm, a width of 110 mm, and a thickness of 2 mm was prepared and left standing at 50 ° C. for 10 days in a box dryer (“PO-50”, manufactured by Matsui Seisakusho Co., Ltd.). The presence or absence of oil bleed on the surface of the test piece was visually confirmed. When the softener (IV) is not bleeding out on the sheet surface and touched by hand, it is good (○), and when the softener (IV) is bleeding out on the sheet surface and touched by hand The case where there was slime was evaluated as bad (x).
○: No softener bleed.
X: Bleeding of softener.

(9) Extrudability (surface property)
The thermoplastic elastomer compositions obtained in the following Examples and Comparative Examples were subjected to a 180 ° C. temperature condition using a 40φ single-screw extruder having a slit die having a width of 30 mm × a thickness of 2.2 mm attached to the outlet portion. A ribbon-shaped molded body was obtained by extrusion molding, and the surface property of the molded body was evaluated using a surface roughness measuring machine (Surfcoder SE1700α manufactured by Kosaka Laboratory Ltd.) with an evaluation length of 4 mm and a measurement speed of 0. Evaluation was made according to the following criteria from the difference between the maximum and minimum surface irregularities when measured at 1 mm / sec.
○: Less than 20 μm The surface is smooth Δ: 20 μm or more and less than 30 μm The surface is rough ×: 30 μm or more The surface is rough

[Production Example 1]
(Production of hydrogenated block copolymer (II) -1)
1.84 kg of styrene and 55.8 kg of cyclohexane as a solvent were charged in a pressure-resistant container substituted with dry nitrogen. To this solution, 45 ml of sec-butyllithium (10% by mass, cyclohexane solution) was added as an initiator and polymerized at 60 ° C. for 1 hour. Next, after adding 305 g of tetrahydrofuran as a Lewis base to this reaction mixture, 8.57 kg of isoprene was added and polymerization was performed for 2 hours, and further 1.84 kg of styrene was added and polymerization was performed for 1 hour to obtain polystyrene-polyisoprene-polystyrene. A reaction solution containing a triblock copolymer was obtained. After sampling a very small amount for analysis, 5% by mass of palladium carbon (palladium supported amount: 5% by mass) as a hydrogenation catalyst was added to the copolymer, and the hydrogen pressure was 2 MPa and 150 ° C. The hydrogenation reaction was carried out for 5 hours under the conditions described above. After cooling and releasing the pressure, palladium carbon was removed by filtration, and then the filtrate was heated again to 80 ° C. and supplied to hot water at 110 ° C. at a rate of 100 kg / hour. At the same time, 1 MPa steam was supplied at a rate of 50 kg / hour, and steam stripping was performed at a temperature in the reaction vessel of 110 ± 2 ° C. The obtained slurry was dehydrated to 45% with a compressed water squeezer, dried by heating with a plate dryer at 120 ° C., and a powdery polystyrene-polyisoprene-polystyrene triblock copolymer having a water content of 0.1% by mass. The hydrogenated product (hereinafter referred to as hydrogenated block copolymer (II) -1) was obtained. The hydrogenated block copolymer (II) -1 obtained had a hydrogenation rate of 97.2%, the content of the polymer block (A) was 29.4% by mass, and the peak top of the polymer block (A) The molecular weight is 37,500, the peak top molecular weight (Mp) of the hydrogenated block copolymer (II) -1 is 315,000, the vinyl bond content of the polymer block (B) is 55.2%, and the bulk density is 0. 0.22 g / ml.

[Production Example 2]
(Production of hydrogenated block copolymer (II) -2)
In Production Example 1, 55.8 kg of cyclohexane as a solvent, 59 ml of sec-butyllithium (10% by mass, cyclohexane solution) as an initiator, and 99 g of N, N, N ′, N′-tetramethylethylenediamine as a Lewis base are polymerized. A polymerization reaction, hydrogenation reaction, decatalyst and drying were carried out in the same manner as in Production Example 1 except that 1.84 kg of styrene, 8.57 kg of butadiene and 1.84 kg of styrene were sequentially added as monomers and polymerized. A hydrogenated product of polybutadiene-polystyrene triblock copolymer was obtained (hereinafter referred to as hydrogenated block copolymer (II) -2). The hydrogenated block copolymer (II) -2 obtained had a hydrogenation rate of 98.8%, the content of the polymer block (A) was 29.3% by mass, and the peak top of the polymer block (A) The molecular weight is 28,500, the peak top molecular weight (Mp) of the hydrogenated block copolymer (II) -2 is 309,000, the vinyl bond content of the polymer block (B) is 73.2%, and the bulk density is 0. 20 g / ml.

[Production Example 3]
(Production of hydrogenated block copolymer (II) -3)
In Production Example 1, 55.8 kg of cyclohexane as a solvent, 53 ml of sec-butyllithium (10 mass%, cyclohexane solution) as an initiator, 1.59 kg of styrene as a monomer to be polymerized without adding a Lewis base, a mixture of isoprene and butadiene [Isoprene / Butadiene = 55/45 (molar ratio)] 7.44 kg, 1.59 kg of styrene were successively added and polymerized in the same manner as in Production Example 1, polymerization reaction, hydrogenation reaction, decatalyst and drying To obtain a hydrogenated product of polystyrene-poly (isoprene / butadiene) -polystyrene triblock copolymer (hereinafter referred to as hydrogenated block copolymer (II) -3). The hydrogenated block copolymer (II) -3 obtained had a hydrogenation rate of 98.9%, the content of the polymer block (A) was 29.4% by mass, and the peak top of the polymer block (A) The molecular weight is 27,500, the peak top molecular weight (Mp) of the hydrogenated block copolymer (II) -3 is 303,000, the vinyl bond content of the polymer block (B) is 8.1%, and the bulk density is 0. 0.22 g / ml.

[Production Example 4]
(Production of hydrogenated block copolymer (II) -4)
In Production Example 1, 55.8 kg of cyclohexane as a solvent, 26 ml of sec-butyllithium (10% by mass, cyclohexane solution) as an initiator, 1.25 kg of styrene as a monomer to be polymerized without adding a Lewis base, a mixture of isoprene and butadiene [Isoprene / butadiene = 55/45 (molar ratio))] 5.83 kg and 1.25 kg of styrene were successively added and polymerized in the same manner as in Production Example 1 to perform polymerization reaction, hydrogenation reaction, decatalyst, and Drying was performed to obtain a hydrogenated product of polystyrene-poly (isoprene / butadiene) -polystyrene triblock copolymer (hereinafter referred to as hydrogenated block copolymer (II) -4). The hydrogenated block copolymer (II) -4 obtained had a hydrogenation rate of 98.7%, the content of the polymer block (A) was 29.4% by mass, and the peak top of the polymer block (A) The molecular weight is 45,800, the peak top molecular weight (Mp) of the hydrogenated block copolymer (II) -4 is 495,000, the vinyl bond content of the polymer block (B) is 7.4%, and the bulk density is 0. .23 g / ml.

[Production Example 5]
(Production of hydrogenated block copolymer (II) -5)
In Production Example 1, 55.8 kg of cyclohexane as a solvent, 65 ml of sec-butyllithium (10% by mass, cyclohexane solution) as an initiator, 312 g of tetrahydrofuran as a Lewis base, 2.02 kg of styrene as a monomer to be polymerized, 9.90 kg of isoprene, The polymerization reaction, hydrogenation reaction, decatalysis and drying were carried out in the same manner as in Production Example 1 except that 2.02 kg of styrene was successively added and polymerized to hydrogenate the polystyrene-polyisoprene-polystyrene triblock copolymer. A product was obtained (hereinafter referred to as hydrogenated block copolymer (a) -5). The resulting hydrogenated block copolymer (II) -5 had a hydrogenation rate of 97.0%, the polymer block (A) content was 28.5% by mass, and the peak top of the polymer block (A). The molecular weight is 26,000, the peak top molecular weight (Mp) of the hydrogenated block copolymer (II) -5 is 225,000, the vinyl bond content of the polymer block (B) is 58.2%, and the bulk density is 0. .44 g / ml.

Olefin-based rubber (I), hydrogenated block copolymer (II), polyolefin-based resin (III), softener (IV), cross-linking agent (V), cross-linking aid (used in the following Examples and Comparative Examples) VI) and the crosslinking accelerator (VII) are as follows.
Olefin rubber (I):
Olefin-based elastomer (ethylene / α-olefin / non-conjugated polyene copolymer rubber) [“JSR EP37F” manufactured by JSR Corporation; iodine value 8, Mooney viscosity (ML _{1 + 4,} 100 ° C.) 100]
Hydrogenated block copolymer (II):
Hydrogenated block copolymer polyolefin resin (III) obtained in Production Examples 1 to 5 above:
Homo polypropylene, Prime Polymer Co., Ltd. E111G [MFR 0.5 g / 10 min (230 ° C., 21.2 N load)]
Softener (IV):
Paraffin process oil [“PW-90” manufactured by Idemitsu Kosan Co., Ltd.]
Cross-linking agent (V) -1:
2,5-dimethyl-2,5-di (t-butylperoxy) hexane [manufactured by NOF Corporation “Perhexa 25B-40”]
Crosslinking agent (V) -2:
Alkylphenol-formaldehyde condensate [Takkol 201 manufactured by Taoka Chemical Co., Ltd.]
Crosslinking aid (VI):
Triallyl isocyanurate / silica = 40/60 [Nippon Kasei Co., Ltd. “TAIC WH-60”]
Cross-linking accelerator (VII):
Two types of zinc oxide [manufactured by Sakai Chemical Industry Co., Ltd.]

[Examples 1-7 and Comparative Examples 1-8]
(Production of thermoplastic elastomer composition by split addition)
In the formulations shown in Tables 2 and 3, (i) olefin rubber (I), polyolefin resin (III), 50% by mass of softener (IV), crosslinking agent (V), crosslinking aid (VI) and (Ii) After 50% by mass of the hydrogenated block copolymer (II) and the softening agent (IV) are preliminarily mixed, a twin-screw extruder (“TEM-35B” manufactured by Toshiba Machine Co., Ltd .; cylinder 5) is used. The composition of (i) above is supplied to the hopper under the conditions of a cylinder temperature of 210 ° C. and a screw speed of 200 rpm, and the composition of (ii) is supplied from the middle of the extruder (cylinder 3). Then, the mixture was melt-kneaded and extruded into a strand shape, and then cut by a pelletizer connected to a twin-screw extruder to produce thermoplastic elastomer composition pellets. Using the obtained thermoplastic elastomer composition pellets, each test piece is prepared, and the hardness, impact resilience, compression set, softener retention, and extrudability (surface properties) are measured by the above methods. The results are shown in Table 2 and Table 3.

[Examples 8 to 9, Comparative Reference Example 1 and Comparative Examples 9 to 10]
(Manufacture of thermoplastic elastomer composition by batch addition)
Each component was premixed with the formulation shown in Tables 2 and 3 and then fed to the hopper of a twin screw extruder (“TEM-35B” manufactured by Toshiba Machine Co., Ltd .; cylinder 5). The mixture was melt-kneaded under the condition of a screw speed of 200 rpm, extruded into a strand, and then cut by a pelletizer connected to a twin-screw extruder to produce thermoplastic elastomer composition pellets. Using the obtained thermoplastic elastomer composition pellets, each test piece is prepared, and the hardness, impact resilience, compression set, softener retention, and extrudability (surface properties) are measured by the above methods. The results are shown in Table 2 and Table 3.

From Table 2, the thermoplastic elastomer compositions obtained in Examples 1 to 9 have hardness (flexibility), rebound resilience (vibration control), compression derived from hydrogenated block copolymer (II) -1. It can be seen that the permanent set, the softener (IV) retainability and the extrudability are excellent and these physical properties are well balanced.

  On the other hand, from Table 3, the thermoplastic elastomer composition obtained in Comparative Example 1 does not contain the hydrogenated block copolymer (II) -1, and thus the softener (IV) The retainability and the extrusion moldability are poor.

  The thermoplastic elastomer composition obtained in Comparative Example 2 had a rebound resilience and extrusion due to the content of polyolefin resin (III) being 5 parts by mass and a value smaller than that of the present invention. Formability is inferior.

  The thermoplastic elastomer composition obtained in Comparative Example 3 has a softener (IV) content of 350 parts by mass, which is a value larger than the provisions of the present invention. Holding property and extrusion moldability are inferior.

  In the thermoplastic elastomer composition obtained in Comparative Examples 4 and 5, the polymer block (B) constituting the hydrogenated block copolymer (II) -2 which is a component thereof is composed only of butadiene units. Therefore, Comparative Example 4 is inferior in impact resilience and extrusion moldability, and Comparative Example 5 is inferior in impact resilience, extrusion moldability and compression set at 120 ° C.

  In the thermoplastic elastomer compositions obtained in Comparative Examples 6 and 7, the vinyl bond content of the polymer block (B) constituting the hydrogenated block copolymer (II) -3 as the component is 8.1%. The rebound resilience and extrusion moldability are inferior due to the fact that the value is smaller than the regulation of the present invention.

  In the thermoplastic elastomer composition obtained in Comparative Examples 8 and 10, the peak top molecular weight (Mp) of the hydrogenated block copolymer (II) -5, which is the component, is 225,000, which is smaller than that of the present invention. Due to the value, the compression set at 70 ° C. and 120 ° C. and the retention of the softening agent (IV) are inferior.

  The thermoplastic elastomer composition obtained in Comparative Example 9 has a vinyl bond content of 7.4% in the polymer block (B) constituting the hydrogenated block copolymer (II) -4 as its component. The hardness, impact resilience, compression set at 70 ° C. and 120 ° C., and extrusion moldability are inferior due to the fact that the value is smaller than that of the invention.

  The thermoplastic elastomer composition of the present invention is excellent in molding processability, flexibility, vibration damping properties, compression set at high temperatures, and softener retention, so that sheets, films, plates, tubes, hoses, It can be used for various molded products such as belts. For example, anti-vibration rubber, mats, seats, cushions, dampers, pads, mount rubber and other anti-vibration / vibration components; footwear for sports shoes, fashion sandals, etc .; household appliances such as TVs, stereos, vacuum cleaners and refrigerators Applications: Building materials such as sealing packing used for building doors and window frames; Automotive interior / exterior components such as bumper parts, body panels, weather strips, grommets, instrument panels, and airbag covers; scissors, Various grips in drivers, toothbrushes, ski stocks, etc .; food packaging materials such as food wrap films; protective films; medical devices such as infusion bags, syringes, and catheters; stoppers for containers for storing food, beverages, drugs, etc. It can be used effectively in a wide range of applications such as cap liners. Kill.

Claims (3)

Olefin rubber (I),
Contains a polymer block (A) composed of a structural unit derived from an aromatic vinyl compound, a structural unit derived from isoprene or a mixture of isoprene and butadiene, and contains 3,4-linked units and 1,2-linked units A hydrogenated product of a block copolymer having a polymer block (B) whose total amount is 45% or more, and having a peak top molecular weight (Mp) of 250 obtained by gel permeation chromatography in terms of standard polystyrene. A hydrogenated block copolymer (II) that is from 1,000,000 to 500,000,
Polyolefin resins (III) other than the above (I)
And a thermoplastic elastomer composition comprising a softener (IV),
Olefin rubber (I) and hydrogenated block copolymer (II) are contained in a ratio of olefin rubber (I): hydrogenated block copolymer (II) = 90: 10 to 10:90 (mass ratio). ,
And 10-200 mass parts of polyolefin-type resin (III) and 10-300 mass parts of softening agents (IV) with respect to a total of 100 mass parts of olefin rubber (I) and hydrogenated block copolymer (II). in a proportion of,
The hydrogenated block copolymer (II) is a powder having a bulk density of 0.10 to 0.40 g / ml,
A thermoplastic elastomer composition obtained by crosslinking a polymer block (B) of the hydrogenated block copolymer (II) and an olefin rubber (I) .   The thermoplastic elastomer composition according to claim 1, wherein the polymer block (B) of the hydrogenated block copolymer (II) comprises a structural unit derived from isoprene. The molded object which consists of a thermoplastic-elastomer composition of Claim 1 or 2 .

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