JP2001081242A - Thermoplastic rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic rubber composition which is excellent in the external appearance, softness, (touch feeling), mechanical strengths and thermal stability and which enables the quality stabilization in order to improve the productivity. SOLUTION: A crosslinked thermoplastic rubber composition comprises 1-99 pts.wt. of (A) a crosslinkable rubbery polymer and 1-99 pts.wt. of (B) a polypropylene-based resin (the sum total of components A and B is 100 pts.wt.), where the component (B) comprises, based on a melt test (under a condition at 200 deg.C) in the presence of an organic peroxide, (B-1) a polypropylene-based resin which has a feature of having developed a torque higher since just after the perfect melt than the M0 which is a torque just after the perfect melt and (B-2) a polypropylene-based resin which has a feature of having been under a condition of a torque lower since just after the melt than the M0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic rubber composition. More specifically, the present invention relates to a thermoplastic rubber composition having excellent appearance, flexibility (touch), mechanical strength, and abrasion resistance.

[0002]

2. Description of the Related Art A rubber-like polymer such as a radically crosslinkable olefinic elastomer and an olefinic resin having no radically crosslinkable property such as PP are crosslinked while being melt-kneaded in an extruder in the presence of a radical initiator. Thermoplastic elastomer compositions by dynamic crosslinking are already known technologies and are widely used in applications such as automobile parts.

As such an olefin elastomer, ethylene-propylene-diene rubber (EPDM) or an olefin elastomer produced by using a metallocene catalyst (JP-A-8-120127, JP-A-9-127)
No. 137001) is known. Further, as a thermoplastic cross-linked rubber composed of an olefin rubber and a special polyolefin resin, for example, thermoplastic cross-linking of an olefin rubber, a degradable polyolefin, and a cross-linked polyolefin composed of ethylene and an α-olefin having 4 to 10 carbon atoms Disclosed is a method for producing a sheet of a thermoplastic crosslinked rubber composition with a rubber composition (JP-A-60-231747), an olefin rubber, a decomposable polypropylene, a crosslinked polyethylene, etc. (JP-A-1-295818). Have been. However, any of the compositions of the above publications have an appearance,
Flexibility (tactile sensation) and mechanical strength are not always sufficient, and there is a need for a high-strength thermoplastic rubber composition that can withstand practical use.

[0004]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention does not have the above-mentioned problems, that is, it is excellent in appearance, flexibility (touch), mechanical strength, and abrasion resistance. Further, it is an object of the present invention to provide a thermoplastic rubber composition capable of stabilizing quality in order to improve productivity.

[0005]

Means for Solving the Problems The inventors of the present invention have intensively studied a rubber-based thermoplastic composition having excellent mechanical strength, and have found that a rubber-like polymer is made of a thermoplastic resin having specific properties. Surprisingly, it has been found that the mechanical strength and abrasion resistance are dramatically improved while maintaining the appearance and flexibility, and the present invention has been completed.

That is, the present invention relates to (A) 1 to 99 parts by weight of a crosslinkable rubbery polymer and (B) a polypropylene resin
99 parts by weight [the total amount of (A) and (B) is 100 parts by weight]
And (B) is a rubber composition obtained by crosslinking
In a melting test of the (B) in the presence of an organic peroxide (at a temperature of 200 ° C.), it has a property that a torque higher than M ₀ exists immediately after melting with respect to a torque M ₀ immediately after complete melting. a polypropylene resin (B-1), thermoplastic rubber composition characterized by comprising from a polypropylene resin (B-2) having properties in the M ₀ following torque state since immediately after melting, and (a ) Ethylene / α-olefin copolymer containing ethylene and α-olefin having 3 to 20 carbon atoms produced using a metallocene catalyst
1 to 99 parts by weight and (B) polyolefin resin 1 to 9
A rubber composition obtained by crosslinking 9 parts by weight [the total amount of (A) and (B) is 100 parts by weight], wherein (B) is a rubber composition in the presence of an organic peroxide. In the melting test (B) (temperature condition: 200 ° C.), a polyethylene-based resin having a property that a torque higher than M ₀ immediately after melting is present with respect to the torque M ₀ immediately after complete melting and / or a carbon number of 4 to 2
A thermoplastic rubber composition comprising: an olefin resin (B-1) mainly containing ₀ and a polyolefin resin (B-2) having a property of being in a torque state of M ₀ or less immediately after melting. It provides things.

Hereinafter, the present invention will be described in detail. The composition of the present invention comprises (A) a specific rubber-like polymer and (B) a specific polyolefin-based resin.

[0008] Here, (B) in the molten test of the present application defines a crosslinkable resin characteristics that there is a high torque than M ₀ since immediately after melting, the characteristics in the M ₀ following torque state since immediately after melt Combined use with a decomposable resin is essential. The presence of the cross-linkable resin suppresses the decomposition of the decomposable resin, resulting in the rubber / resin having a close viscosity ratio and excellent expression, flexibility (touch), mechanical strength, and abrasion resistance. In addition, the inventors have found that the quality can be stabilized because the productivity is improved, and the present invention has been completed.

Hereinafter, each component of the present invention will be described in detail. In the present invention, (A) the crosslinkable rubber-like polymer preferably has a glass transition temperature (Tg) of -30 ° C or lower. Examples of such a rubber-like polymer include polybutadiene and poly (styrene-butadiene). , Poly (acrylonitrile-butadiene) and other diene rubbers and hydrogenated hydrogenated saturated rubbers, isoprene rubber, chloroprene rubber, acrylic rubbers such as polybutyl acrylate, ethylene-propylene copolymer rubber, ethylene-propylene rubber -Diene monomer terpolymer rubber (EPD
M), a crosslinked rubber or a non-crosslinked rubber such as an ethylene-octene copolymer rubber, and a thermoplastic elastomer containing the above rubber component.

In the present invention, among the crosslinkable rubbery polymers (A), ethylene / α-olefin copolymers are particularly preferred, and ethylene and α-olefins having 3 to 20 carbon atoms are more preferred.

The α-olefin having 3 to 20 carbon atoms includes, for example, propylene, butene-1, pentene-
1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, and the like. Among them, hexene-1, 4-methylpentene-1 and octene-1 are preferred, and α-olefins having 6 to 12 carbon atoms are particularly preferred, and octene-1 is most preferred. Octene-1 is excellent in softening effect even in a small amount, and the obtained copolymer is excellent in mechanical strength.

The (A) ethylene / α-olefin copolymer suitably used in the present invention is preferably produced using a known metallocene catalyst.

In general, a metallocene-based catalyst is composed of a cyclopentadienyl derivative of a Group IV metal such as titanium or zirconium and a co-catalyst, and is not only highly active as a polymerization catalyst but also has a higher activity than a Ziegler-based catalyst. The molecular weight distribution of the resulting polymer is narrow, and the distribution of the comonomer α-olefin having 3 to 20 carbon atoms in the copolymer is uniform.

The ethylene / α-olefin copolymer (A) used in the present invention preferably has an α-olefin copolymerization ratio of 1 to 60% by weight, more preferably 10 to 50% by weight, most preferably 10 to 50% by weight. Preferably it is 20 to 45% by weight. α-olefin copolymerization ratio is 60% by weight
If it exceeds 1, the hardness, tensile strength and the like of the composition are greatly reduced, while if it is less than 1% by weight, the flexibility and the mechanical strength are reduced.

(A) Ethylene / α-olefin copolymer
Has a density of 0.8 to 0.9 g / cm. ^TwoIn the range of
Is preferred. Olefins having a density in this range
Excellent flexibility and low hardness by using stoma
Thus, an elastomer composition can be obtained.

(A) Ethylene α used in the present invention
-The olefin copolymer desirably has a long-chain branch. The presence of the long-chain branch enables the density to be lower than the ratio (% by weight) of the copolymerized α-olefin without lowering the mechanical strength. Hardness and high strength elastomer can be obtained. The olefin elastomer having a long chain branch is described in US Pat. No. 5,278,272.

The (A) ethylene / α-olefin copolymer preferably has a DSC melting point peak at room temperature or higher.

When it has a melting point peak, the form is stable in the temperature range below the melting point, the handleability is excellent, and the stickiness is small.

The melt index of (A) used in the present invention is 0.01 to 100 g / 10 min (19
(0 ° C., 2.16 kg load) is preferably used, and more preferably 0.2 to 10 g / 10 min.
If the amount exceeds 100 g / 10 minutes, the crosslinking property of the composition is insufficient.

(A) used in the present invention may be a mixture of a plurality of types. In such a case, it is possible to further improve the workability.

In the present invention, one of the preferred crosslinkable rubbery polymers among (A) is a thermoplastic elastomer, and among them, a polystyrene thermoplastic elastomer is particularly preferred. Or a block copolymer in which the above conjugated diene unit is partially hydrogenated or epoxy-modified.

The aromatic vinyl monomer constituting the block copolymer is, for example, styrene, α-methylstyrene, paramethylstyrene, p-chlorostyrene, p-bromostyrene, 2,4,5-tribromobenzene. Styrene is the most preferable, and styrene is most preferable. However, other aromatic vinyl monomers described above may be copolymerized mainly with styrene.

Further, examples of the conjugated diene monomer constituting the block copolymer include 1,3-butadiene and isoprene.

In the block structure of the block copolymer, a polymer block composed of an aromatic vinyl unit is represented by S, and a polymer composed of a conjugated diene and / or a partially or completely hydrogenated unit thereof. When a block is represented by B, a linear block copolymer of SB, S (BS) n (where n is an integer of 1 to 3), and S (BSB) n (where n is an integer of 1 to 2) Or (SB) nX (where n
Is an integer of 3 to 6. X is a residue of a coupling agent such as silicon tetrachloride, tin tetrachloride, and a polyepoxy compound. ),
It is preferably a star block copolymer having a B portion as a bonding center. Above all, type 2 of SB, SBS
Type 3 and SBSB type 4 linear-block copolymers are preferred.

In the present invention, another preferred hydrogenated copolymer of (A) is a total of unsaturated rubber comprising a polymer having a double bond in a main chain and a side chain and / or a random copolymer. More than 50% of the double bonds are hydrogenated rubber.

The total double bond in the hydrogenated rubber is 50
% Or more, preferably 90% or more, more preferably 95% or more, and the remaining double bond in the main chain is 5% or less and the remaining double bond in the side chain is 5% or less. preferable. Specific examples of such a rubber include a rubbery polymer obtained by partially or completely hydrogenating a diene rubber such as polybutadiene, poly (styrene-butadiene), poly (acrylonitrile-butadiene), polyisoprene, and polychloroprene. Hydrogenated butadiene rubber or hydrogenated isoprene rubber is particularly preferable.

Such a hydrogenated rubber can be obtained by partially hydrogenating the above rubber by a known hydrogenation method. For example, FLRamp, etal, J.Amer.Chem.Soc., 83,46
72 (1961), a method for hydrogenation using a triisobutylborane catalyst, Hung Yu Chen, J. Polym. Sci. Polym. Let
ter Ed., 15,271 (1977), a method of hydrogenation using toluenesulfonyl hydrazide;
There can be mentioned a method of hydrogenation using an organic cobalt-organoaluminum catalyst or an organic nickel-organoaluminum catalyst described in JP-A-2-8704. Here, a particularly preferred hydrogenation method is a low temperature,
JP-A-59-133203 and JP-A-60-220147 using catalysts capable of hydrogenation under low pressure and mild conditions
Patent Publication or an inert organic solvent, a bis (cyclopentadienyl) titanium compound and a sodium atom,
This is a method described in JP-A-62-207303 in which hydrogen is brought into contact with a hydrocarbon compound having a potassium atom, a rubidium atom or a cesium atom in the presence of a catalyst.

The Mooney viscosity (ML) of the hydrogenated rubber measured at 100.degree.
The weight% styrene solution viscosity (5% SV) is 20 to 300
It is preferably in the range of centipoise (cps).
A particularly preferred range is 25 to 150 cps.

The endothermic peak calorie, which is an index of the crystallinity of the hydrogenated rubber, is controlled by adding a polar compound such as tetrahydrofuran or controlling the polymerization temperature. The reduction of the endothermic peak calorific value is achieved by increasing the amount of the polar compound or decreasing the polymerization temperature to increase the 1,2-vinyl bond.

(A) used in the present invention may be a mixture of a plurality of types. In such a case, it is possible to further improve the workability.

(A) used in the present invention may be a mixture of a plurality of types. In such a case, it is possible to further improve the workability.

In the present invention, the polypropylene resin (B) is a resin mainly composed of propylene units. In the melting test prescribed in the present application, a crosslinked polypropylene resin having a property that a torque higher than M0 exists immediately after melting ( B
-1) and a decomposable polypropylene resin (B-2) having a torque state of M0 or less immediately after melting.

The polypropylene resin (B-1) used in the present invention is not particularly limited as long as it satisfies the melting characteristics in the melting test prescribed in the present application. Specific examples of (B-1) are copolymer resins containing propylene in an amount of 50% by weight or more. In particular, as a monomer copolymerizable with propylene, ethylene or an α-olefin having 4 to 20 carbon atoms is used. preferable. A random copolymer resin of ethylene and propylene is most preferable, and when an ethylene component is present in the polymer main chain, it becomes a crosslinking point of a crosslinking reaction,
The properties of the crosslinked polypropylene resin are shown.

The proportion of the monomer copolymerizable with propylene is preferably from 1 to 49% by weight, more preferably from 2 to 40% by weight, even more preferably from 3 to 30% by weight in (B-1). Very preferably 5 to 20% by weight, most preferably 5 to 10% by weight.

Such (B-1) is based on JIS K67
58-specified flexural modulus of 100 to 10,000 kgf / c
m ² , and in the differential scanning calorimetry (DSC method), an endothermic peak exists in a temperature range of 100 to 150 ° C., and when the above-mentioned endothermic peak calorie is in a range of 10 to 600 J / g, it is excellent. Appearance, flexibility (touch), mechanical strength, and thermal stability are exhibited.

The polypropylene resin (B-2) used in the present invention is not particularly limited as long as it satisfies the melting characteristics in the melting test specified in the present application. Specific examples of (B-2) are a single resin or a copolymer resin containing 50% by weight or more of propylene, and particularly, as a monomer copolymerizable with propylene, ethylene or a C4 to C2 monomer.
Α-olefin of 0 is preferable, and is an isotactic copolymer resin of homo isotactic polypropylene, propylene and another α-olefin such as butene-1, pentene-1, hexene-1, and the like. Resins are preferred.

As (B-2), it is preferable that an ethylene unit is not contained in the polymer main chain. However, when an ethylene-α-olefin copolymer is present as a dispersed phase, as in a propylene-based block copolymer resin, it exhibits the characteristics of a decomposable polypropylene-based resin.

The polypropylene resin used in the present invention has a melt index of 0.1 to 100 g / g.
Those having a range of 10 minutes (230 ° C., 2.16 kg load) are preferably used. If it exceeds 100 g / 10 minutes, the heat resistance and mechanical strength of the composition will be insufficient, and
If it is less than g / 10 minutes, the fluidity is poor and the molding processability is undesirably reduced.

(B-2) is composed mainly of α-olefin, and (B) may be a combination of a plurality of (B-1) and (B-2) components.

In 100 parts by weight of the composition comprising (A) and (B), (B) is used in a composition ratio of 1 to 99 parts by weight. Preferably 5 to 90 parts by weight, more preferably 2
0 to 80 parts by weight. If the amount is less than 1 part by weight, the fluidity and processability of the composition are reduced, and if it exceeds 99 parts by weight, the flexibility of the composition is insufficient, which is not desirable.

The thermoplastic rubber composition of the present invention is a crosslinked thermoplastic rubber composition comprising the above components (A) and (B). Crosslinking is partial or complete crosslinking.

The partially or completely crosslinked thermoplastic rubber composition of the present invention is preferably crosslinked with (C) a crosslinking agent. (C) contains (C-1) a crosslinking initiator as an essential component, and if necessary, (C-2) a polyfunctional monomer, and (C-3)
Contains a monofunctional monomer.

The above (C) is used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the composition comprising (A) and (B). If the amount is less than 0.01 part by weight, the crosslinking is insufficient, and if it exceeds 10 parts by weight, the appearance and mechanical strength of the composition decrease.

Here, the (C-1) crosslinking initiator includes a radical initiator such as an organic peroxide and an organic azo compound, and specific examples thereof include 1,1-bis (t-butyl). Peroxy) -3,3,5-trimethylcyclohexane,
1,1-bis (t-hexylperoxy) -3,3,5
-Trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-
Butylperoxy) cyclododecane, 1,1-bis (t
-Butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,
Peroxy ketals such as 4-bis (t-butylperoxy) butane and n-butyl-4,4-bis (t-butylperoxy) valerate; di-t-butyl peroxide, dicumyl peroxide, t -Butylcumyl peroxide, α, α′-bis (t-butylperoxy-m
-Isopropyl) benzene, α, α'-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5 Dialkyl peroxides such as -bis (t-butylperoxy) hexyne-3;

Acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,
Diacyl peroxides such as 5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and m-trioyl peroxide; t-butylperoxyacetate, t-butylperoxyisobuty Rate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate,
2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-
Peroxyesters such as butylperoxyisopropyl carbonate and cumylperoxyoctate;

Further, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide and 1,
Hydroperoxides such as 1,3,3-tetramethylbutyl peroxide can be exemplified.

Among these compounds, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl -2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 are preferred.

The above (C-1) is preferably 1 to 80% by weight, more preferably 10 to 50% by weight in the component (C).
Is used. If the amount is less than 1% by weight, crosslinking is insufficient, and if it exceeds 80% by weight, the mechanical strength decreases.

In the present invention, one of the polyfunctional monomers (C-2) of the crosslinking agent (C) is preferably a radically polymerizable functional group as a functional group, and particularly preferably a vinyl group. Although the number of functional groups is 2 or more, it is effective especially in the case of having 3 or more functional groups in combination with (C-3). Specific examples include divinylbenzene, triallyl isocyanurate, triallyl cyanurate, diacetone diacrylamide, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate,
Trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diisopropenylbenzene, P-quinone dioxime, P,
P'-dibenzoylquinone dioxime, phenylmaleimide, allyl methacrylate, N, N'-m-phenylenebismaleimide, diallyl phthalate, tetraallyloxyethane, 1,2-polybutadiene and the like are preferably used. Particularly, triallyl isocyanurate is preferable. These polyfunctional monomers may be used in combination of two or more.

The above (C-2) is preferably 1 to 80% by weight, more preferably 10 to 50% by weight in the component (C).
Is used. If the amount is less than 1% by weight, the effect is insufficient, and if it exceeds 80% by weight, the mechanical strength decreases.

The above (C-3) used in the present invention
Is a vinyl monomer added to control the crosslinking reaction rate, preferably a radical polymerizable vinyl monomer, and an aromatic vinyl monomer, acrylonitrile, unsaturated nitrile monomer such as methacrylonitrile, etc. Body, acrylic acid ester monomer, methacrylic acid ester monomer, acrylic acid monomer, methacrylic acid monomer, maleic anhydride monomer,
And N-substituted maleimide monomers.

The above (C-3) is preferably 1 to 80% by weight, more preferably 10 to 50% by weight in the component (C).
Is used. If the amount is less than 1% by weight, the effect is insufficient, and if it exceeds 80% by weight, the mechanical strength decreases.

The thermoplastic rubber composition of the present invention may optionally contain (D) a softening agent for improving processability.

The above (D) is preferably a paraffinic or naphthenic process oil. These are used for adjusting the hardness and flexibility of the composition in an amount of 5 to 500 parts by weight, preferably 10 to 150 parts by weight, per 100 parts by weight of the composition comprising (A) and (B). If less than 5 parts by weight, flexibility,
If the workability is insufficient, and if it exceeds 500 parts by weight, oil bleed becomes remarkable, which is not desirable.

In the present invention, (A) an ethylene / α-olefin copolymer containing ethylene and an α-olefin having 3 to 20 carbon atoms produced using a metallocene catalyst, or a copolymer having two or more main and side chains. When using a hydrogenated rubber in which 50% or more of the total double bonds of the unsaturated rubber composed of a polymer having a heavy bond and / or a random copolymer is hydrogenated, a polyolefin resin is used as (B). be able to. Particularly preferred is a combination of a polyethylene resin and / or an olefin resin (B-1) mainly containing 4 to 20 carbon atoms and another polyolefin resin (B-2). In this case, not only the appearance, flexibility (tactile sensation), mechanical strength, thermal stability and quality stability are excellent, but also excellent scratch resistance is exhibited.

The above (A) is an ethylene / α-olefin copolymer produced by using a metallocene catalyst or a hydrogenated rubber, which is shown in the above-mentioned crosslinkable rubber polymer.

The polyethylene resin (B-1) is not particularly limited as long as it satisfies the melting characteristics in the melting test specified in the present application. Specific examples of (B-1) include a homo-resin or a copolymer resin containing 50% by weight or more of ethylene, and particularly a C3-C20 α-olefin as a monomer copolymerizable with ethylene. Are preferred, homo low density polyethylene, high density polyethylene,
It is a linear low-density polyethylene or a copolymer resin with other α-olefins such as propylene, butene-1, pentene-1, and hexene-1.

The polyolefin resin (B-2) is not particularly limited as long as it satisfies the melting characteristics in the melting test specified in the present application. As a specific example of (B-2), a single resin or a copolymer resin containing 50% by weight or more of propylene is preferable. In particular, as a monomer copolymerizable with propylene, ethylene or α having 4 to 20 carbon atoms is used. -An olefin is preferred, and a block copolymer resin is more preferred.

As (B-2), it is preferable that no ethylene unit is contained in the polymer main chain. However, when an ethylene-α-olefin copolymer is present as a dispersed phase, as in a propylene-based block copolymer resin, it exhibits the characteristics of a decomposable polypropylene-based resin.

The composition of the present invention can contain an inorganic filler and a plasticizer to such an extent that its characteristics are not impaired. As the inorganic filler used here, for example,
Calcium carbonate, magnesium carbonate, silica, carbon black, glass fiber, titanium oxide, clay, mica,
Examples include talc, magnesium hydroxide, and aluminum hydroxide. Examples of the plasticizer include phthalic acid esters such as polyethylene glycol and dioctyl phthalate (DOP). Also, other additives, for example, organic and inorganic pigments, heat stabilizers, antioxidants,
UV absorbers, light stabilizers, flame retardants, silicone oils, antiblocking agents, foaming agents, antistatic agents, antibacterial agents and the like are also suitably used.

For the production of the composition of the present invention, general methods such as a Banbury mixer, a kneader, a single-screw extruder, and a twin-screw extruder used in the production of ordinary resin compositions and rubber compositions are employed. It is possible to In particular, a twin-screw extruder is preferably used to achieve dynamic crosslinking efficiently. The twin-screw extruder is used for dispersing (A) and (B) uniformly and finely and further adding other components to cause a cross-linking reaction to continuously produce the composition of the present invention. ,
More suitable.

The composition of the present invention comprises (B-1) and (B-
When (2) is simultaneously present, it is preferred to crosslink (A) with a (C) crosslinker. When crosslinking is performed with (C) in the presence of (A) and (B-1), (B-1) is also crosslinked with (A), and the appearance is reduced. On the other hand, when cross-linking with (C) in the presence of (A) and (B-2), (A) is cross-linked, but (B)
-2) is decomposed and the mechanical strength is significantly reduced.

As a preferred specific example, it can be manufactured through the following processing steps. That is, (A) and (B) are mixed well and put into a hopper of an extruder.
(C) may be added together with (A) and (B) from the beginning, or may be added from the middle of the extruder. The oil may be added from the middle of the extruder, or may be added separately at the beginning and during the middle. A part of (A) and (B) may be added in the middle of the extruder. When heated and melted and kneaded in an extruder, the above (A) and (C) undergo a cross-linking reaction, and further (D) a softening agent is added and melt-kneaded to make the cross-linking reaction and kneading dispersion sufficient. Thereafter, by taking out from the extruder, pellets of the composition of the present invention can be obtained.

A particularly preferred melt extrusion method is to have a length L in the die direction from the raw material addition portion and
This is the case where a twin-screw extruder with / D of 5 to 100 (where D is the barrel diameter) is used. The twin-screw extruder has a plurality of supply portions of a main feed portion and a side feed portion having different distances from a tip portion thereof, and between a plurality of the supply portions and between the tip portion and the tip portion. It is preferable that a kneading part is provided between the supply part and a kneading part close to the feeding part, and the length of the kneading part is 3D to 10D.

One twin-screw extruder of the production apparatus used in the present invention may be a twin-screw co-rotating extruder or a twin-screw different-direction rotating extruder. In addition, regarding the screw engagement, non-engagement type, partial meshing type,
There is a complete meshing type, and any type may be used. In order to obtain a uniform resin at a low temperature by applying a low shearing force, a different direction rotation / partial engagement screw is preferable. When slightly large kneading is required, a co-rotating / completely meshing screw is preferable. When even greater kneading is required, a co-rotating and fully meshing screw is preferred.

In the present invention, the morphology of the composition comprising the components (A) and (B) is also important for improving the appearance and the mechanical strength, and the component (A) exists as independent particles. It is necessary that the component (B) be in a continuous phase, and for that purpose, for example, it is important to suppress the crosslinking rate under a high shear force. Specifically, it is achieved by reducing the amount of a crosslinking initiator or a crosslinking assistant and performing a reaction at a temperature as low as possible and for a long time, which is higher than the decomposition temperature of the crosslinking initiator. It can also be achieved by using a polyfunctional monomer and a monofunctional monomer in combination as a crosslinking aid. Excessive addition of a crosslinking initiator and a crosslinking aid, or excessively high activity of a crosslinking initiator, a crosslinking aid and high-temperature reaction conditions cause aggregation of the rubbery polymer and do not satisfy the requirements of the present application.
By mixing a crosslinking initiator and a crosslinking assistant into (A) while preliminarily absorbing a small amount of (D) a softening agent in (A), the crosslinking reaction proceeds gently. Can be generated.

As a production method for achieving excellent appearance and improvement in mechanical strength, it is more preferable to satisfy the following kneading degree. ^{M = (π 2/2)} (L / D) D 3 (N / Q) 10 × 10 6 ≦ M ≦ 1000 × 10 6 where, L: die direction of extrusion PIC material added section as a base point (mm), D: extruder barrel inner diameter (mm), Q: discharge rate (kg / h), N: screw rotation speed (rpm)

[0068] kneading degree ^{M = (π 2/2)} (L / D) D
It is important that ³ (N / Q) is 10 × 10 ⁶ ≦ M ≦ 1000 × 10 ⁶ . When M is less than 10 × 10 ⁶ , the rubber particles are enlarged and agglomerated, and the appearance is deteriorated. On the other hand, when M exceeds 1000 × 10 ⁶ , excessive shear force causes
The mechanical strength decreases.

To achieve better appearance and mechanical strength, it is preferable to satisfy the melting temperature of the following relational expression. That is, first, melt-kneading is performed at a melting temperature T ₂ (° C.), and then melt-kneading is performed at a melting temperature T ₃ (° C.). 0.1 L to 0.5 from the addition port
First, the extruder zone having a length of L is melt-kneaded at a melting temperature T ₂ (° C.), and then the extruder zone is melted at a melting temperature T ₂ (° C.).
₃ Melt and knead at (° C).

Here, it is particularly preferable that T ₁ is 150 to 250 ° C., and T ₁ or T _{2 in} each zone of the melt extruder may be a uniform temperature, or may have a temperature gradient. Is also good.

T ₁ : 1 minute half-life temperature (° C.) of (C) T ₁ −100 <T ₂ <T ₁ +40 T ₂ +1 <T ₃ <T ₂ +200

The rubber composition thus obtained can be used to produce various molded articles by any molding method. Injection molding, extrusion molding, compression molding, blow molding, calender molding, foam molding and the like are preferably used.

[0073]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In these examples and comparative examples, the test methods used for evaluating various physical properties are as follows.

(1) Tensile breaking strength [MPa] From a T-die extruded sheet, a value of 2 was obtained in accordance with JIS K6251.
The evaluation was performed at 3 ° C. (2) Tensile rupture elongation [%] From a T-die extruded sheet, 2 according to JIS K6251
The evaluation was performed at 3 ° C. (3) MFR [g / 10 min] 190 ° C., 2.16 k according to ASTM D1238
The evaluation was performed under the condition of g load.

(4) Appearance The appearance was evaluated from the sheet skin according to the following criteria. ◎ Very good ○ Good △ Good, but somewhat rough × Overall rough. No luster

(5) Flexibility (Tactile Feeling) Flexibility was evaluated from the sheet skin according to the following criteria. ◎ Extremely flexible and good tactile feeling ○ Good △ Good, but a little hardness is felt × Hard overall and bad tactile feeling

(6) Scratch resistance The tip is a rectangle having a length of 10 mm and a width of 1 mm and a weight of 30 mm.
The sheet was scratched by dropping a 0 g wedge from a height of 5 cm onto the sheet, and the sheet was visually evaluated according to the following criteria. ◎ Very good ○ Good △ Good, but noticeable scratches × Notable scratches

(7) Abrasion resistance A molded product was compression-molded to produce a sheet, and a 5 cm × 5 cm × 2 mm stainless plate with a felt cloth adhered to the lower surface was placed on the sheet under the following evaluation conditions. Was. Apparatus: Gakushin-type abrasion tester Temperature condition: 23 ° C atmosphere Stroke: 120 mm Frequency: 1 round trip / 2 seconds Load: 1 kg Friction material: 100% cotton cloth Kanakin No. 3 (JIS L)
0803) Tri-folded and attached Contact area: 1 square cm The evaluation is the number of times of friction reciprocation until the surface texture of the molded product disappears

(8) Extrusion Stability (Quality Stability) Using a melt extruder, the resin composition was continuously melt-extruded for 10 hours, and the tensile rupture strength (Tb) of the composition obtained every hour was measured. The continuous productivity (quality stability) was evaluated from the rate of change (%) of the maximum (Tb) ₁ relative to the average (Tb) ₀ . Tb change rate (%) = 100 × [(Tb) ₁ − (Tb)
₀ ] / (Tb) ₀

(9) Melting test Using a Labo Plast Mill manufactured by Toyo Seiki Seisaku-sho, the weight ratio was polyolefin resin / POX-1 / DVB = 100 /
The composition of 0.67 / 1.33 is melt-kneaded for 10 minutes at a set temperature of 200 ° C. and a rotation speed of 100 rpm (POX-1 and DVB will be described later). When the resin in the pellet state is charged into the Labo Plastomill, the pellet state is changed to a semi-molten state, and finally to a molten state without retaining the shape, but the torque immediately after the molten state is reduced to the torque M ₀ immediately after the melting. and said torque M ₀ immediately after melting behavior and melt is shown as starting point immediately after melting in FIG.

(10) Analysis of conjugated diene rubber 1) Hydrogenation rate (%) It was measured by NMR according to the following procedure. First, polybutadiene rubber before hydrogenation was dissolved in deuterated chloroform, and FT-N
Chemical shift 4.7 with MR (270 mega, manufactured by JEOL)
~ 5.2 ppm (assumed as signal C0) of protons (= CH ₂ ) by 1,2-vinyl, and a chemical shift of 5.2 to 5.2
From the integrated intensity of 5.8 ppm (referred to as signal D0) vinyl proton (= CH ₂ ), it was calculated by the following equation. (V) = [0.5C0 / ｛0.5C0 + 0.5 (D0−
0.5C0)｝] × 100

Next, the polybutadiene rubber after partial hydrogenation was dissolved in deuterated chloroform, and similarly, by FT-NMR, a chemical shift of 0.6 to 1.0 ppm (referred to as signal A1) was added to hydrogenated 1,1. 2 coupled with methyl group protons (-CH _3), chemical shift 4.7~5.2ppm
1,2 not hydrogenated (referred to as signal C1)
- Proton by vinyl (= CH _2), the chemical shift 5.
It was calculated by the following equation from the integrated intensity of 2-5.8 ppm (assumed as signal D1) of a non-hydrogenated vinyl proton (= CH).

First, p = 0.5C0 / (0.5C1 + A
1/3) A11 = pA1, C11 = pC1, D11 = pD1, and the hydrogenation rate of the 1,2-vinyl bond (B) (B) = [(A11 / 3) / ｛A11 / 3 + C11 /
2｝] × 100 Hydrogenation rate of 1,4-double bond (C) (C) = [｛0.5 (D0−0.5C0) −0.5 (D
11-0.5C11)｝ / 0.5 (D0-0.5C
0)] × 100 Hydrogenation rate of whole butadiene part (A) (A) = (V) × (B) / 100 + [100− (V)]
× (C) × 100

2) Microstructure The symbols defined above are described below. 1,2-vinyl bond before hydrogenation = (V) × (B) / 100 (%) 1,4 bond before hydrogenation = {100− (V)} × (C) / 100 (%) Hydrogenation 1,2-bond after hydrogen = (V) × {100- (B)} / 100 (%) 1,4-bond after hydrogenation = {100- (V)} × {100- (B)} / 100 (%)

(11) Light stability As a light stability tester, ATLAS Electric Devices Co., USA
JIS K7 using ATLAS CI35W Weatherometer
102. Irradiation conditions include
Tester internal temperature, 55 ° C, humidity 55%, no rain, xenon light (wavelength 340nm, energy 0.30W / m ² )
Irradiation was performed for 300 hours. After irradiation, the appearance of the sheet was visually evaluated according to the following criteria. ◎ Extremely good ○ Good △ Good, but somewhat rough × Overall rough. The following components were used for each component used in Examples and Comparative Examples.

(A) Rubbery polymer Copolymer of ethylene and octene-1 (TPE-1) It was produced by a method using a metallocene catalyst described in JP-A-3-16388. The ethylene / octene-1 composition ratio of the copolymer is 72/28 (weight ratio) (referred to as TPE-1).

Copolymer of ethylene and octene-1 (TPE-2) The copolymer was prepared by a method using an ordinary Ziegler catalyst. The ethylene / octene-1 composition ratio of the copolymer is 72/2.
8 (weight ratio) (referred to as TPE-2).

Ethylene / propylene / dicyclopentadiene copolymer (TPE-3) This was produced by a method using a metallocene catalyst described in JP-A-3-16388. The composition ratio of ethylene / propylene / dicyclopentadiene in the copolymer is 72/2.
4/4 (weight ratio) (referred to as TPE-3).

Styrene-ethylene-butylene-styrene copolymer (SEBS) manufactured by Asahi Kasei Kogyo Co., Ltd. (trade name: Tuftec (referred to as SEBS)) Styrene-butadiene copolymer (SB) Asahi Kasei Kogyo Co., Ltd. [trade name Tufprene (referred to as SB)] Hydrogenated rubber Polybutadiene and styrene-butadiene copolymer (manufactured by Asahi Kasei Kogyo Co., Ltd.) were produced by hydrogenating 0 to 100% by a known method.

(B) Polyolefin-based resin Polypropylene (PP-1): decomposable type (B-2) Isotactic homopolypropylene [MFR (30 g / min) (ASTM D) manufactured by Nippon Polyolefin Co., Ltd.
230 ° C, 2.16 kg load according to 1238)] (P
P-1)

Polypropylene (PP-2): Decomposed type (B-2) Isotactic homopolypropylene [MFR (0.5 g / min) (ASTM D) manufactured by Nippon Polyolefin Co., Ltd.
230 ° C, 2.16 kg load according to 1238)
(Referred to as PP-2)

Ethylene (ET) -propylene (PP)
Copolymer resin: Decomposition type (B-2) Nippon Polyolefin Co., Ltd., block ET-PP resin [ET / PP = 7/93 (weight ratio)] (referred to as EP-0)

Ethylene (ET) -propylene (PP)
Copolymer resin: Cross-linked (B-1) Random ET-PP resin [ET / PP = 7/93 (weight ratio) (trade name: PM94), manufactured by Japan Polyolefin Co., Ltd.]
0M)] (referred to as EP-1) On the basis of the composition of EP-1, a random ET-PP copolymer resin having a different composition was produced by a known production method while changing the amount ratio of ethylene and propylene.

Low-density polyethylene: cross-linked (B-1) Suntec LD (LDPE) manufactured by Asahi Kasei Corporation

(C) Crosslinking agent 1) Crosslinking initiator (C-1) 2,5-dimethyl-2,5-bis (t-manufactured by NOF CORPORATION)
Butylperoxy) hexane (trade name Perhexa 25)
B) (referred to as POX-1)

2) Crosslinking initiator (C-1) 2,5-dimethyl-2,5-bis (t-manufactured by NOF Corporation)
Butyl peroxy) hexin-3 (trade name perhexin 25B) (referred to as POX-2)

3) Polyfunctional monomer (C-2) divinylbenzene (referred to as DVB) manufactured by Wako Pure Chemical Industries, Ltd.

4) Polyfunctional monomer (C-2) Triallyl isocyanurate (TA) manufactured by Nippon Kasei Co., Ltd.
(Referred to as IC)

5) Multifunctional monomer (C-2) N, N'-m phenylenebismaleimide (referred to as PMI) manufactured by Ouchi Shinko Chemical Co., Ltd. 6) Monofunctional monomer (C-3) Asahi Kasei Kogyo Co., Ltd., Methyl methacrylate (referred to as MMA)

7) Monofunctional monomer (C-3) Styrene (referred to as ST) manufactured by Asahi Kasei Kogyo Co., Ltd.

(D) Paraffin oil Diana Process Oil PW-9 manufactured by Idemitsu Kosan Co., Ltd.
0 (referred to as MO)

Reference Examples 1 to 5 The weight ratio of thermoplastic resin / POX-1 / DVB = 100 / 0.67 was measured using a Labo Plast Mill manufactured by Toyo Seiki Seisaku-sho, Ltd.
/1.33 composition at a set temperature of 200 ° C. and a rotation speed of 10
The mixture was melt-kneaded at 0 rpm for 10 minutes. The result is shown in FIG. The thermoplastic resins used are as follows.

Reference Example Thermoplastic Resin Reference Example 1 PP-1 Reference Example 2 EP-1 Reference Example 3 PP-1 / EP-1 = 50/50 Reference Example 4 PP-1 / LDPE = 90/10 Reference Example 5 PP-1 / LDPE = 50/50

In a melting test (temperature condition: 200 ° C.) in the presence of an organic peroxide as defined in the present application, EP-1 (Reference Example 2) showed a torque M ₀ immediately after complete melting and a torque M ₀ immediately after melting. is a typical cross-linked thermoplastic resin having a characteristic of high torque from the M ₀ is present (B-1), PP- 1
(Reference Example 1) is a typical decomposable thermoplastic resin (B) having a characteristic of being in a torque state of M ₀ or less immediately after melting.
-2).

According to FIG. 1, the decomposition of the decomposable thermoplastic resin is suppressed by the combined use of the crosslinked / decomposed thermoplastic resin, while the cross-linking reaction of the crosslinked thermoplastic resin is suppressed. It can be seen that thermal stabilization of the resin is promoted.

Example 1, Comparative Examples 1 and 2 The experiment was repeated in the same manner as in Reference Example 1 with the compositions shown in Table 1,
The decomposition rate of (B) was evaluated from the MFR change rate. That is,
The MFR without the addition of affecting crosslinking / disassembly (C) (D) component and MI _0, and MI ₁ to MFR in the case of adding (C) (D) _component, the ratio of MI 1 / MI ₀ Is defined as the decomposition rate. The results are shown in Table 1 and FIG.

According to Table 1 and FIG. 2, the decomposition rate MI ₁ /
It can be seen that MI ₀ is lower than that of each of them alone and is thermally stabilized.

[0108]

[Table 1]

Example 2, Comparative Examples 3 and 4 The same experiment as in Reference Example 1 was repeated with the compositions shown in Table 2.
However, after (A) to (D) were added all at once, the reaction was carried out for 10 minutes, then (E) was added, and the reaction was carried out for another 10 minutes under the same conditions.

From the composition thus obtained, 200
A sheet having a thickness of 2 mm was prepared by compression molding at ℃, and various characteristics were evaluated. The results are shown in Table 2 and FIG.

According to Table 2 and FIG. 3, when the decomposed type PP-2 was used as (B) (Comparative Example 3), the torque rapidly decreased after the dynamic crosslinking reaction of (A). When the decomposition type PP-2 / crosslinked type EP-1 is used in combination as (B) (Example 2), the decrease in the torque becomes slow, and the decrease in the molecular weight of (B) is suppressed. It can be seen that it improves.

[0112]

[Table 2]

Examples 3 to 11 and Comparative Examples 5 to 9 Using a twin-screw extruder (25 mmφ, L / D = 47) consisting of 11 blocks having an inlet at the center of the barrel, see Table 3
The composition described was melt-kneaded in the following manner on the basis of the following melting conditions. As the screw, a double screw having a kneading portion before and after the injection port was used. In addition, MO
In the case of using, an extruder was used to perform injection by a pump through an injection port at the center of the extruder to perform melt extrusion.

(Reference Melting Conditions) 1) Melt extrusion temperature constant at 220 ° C. 2) Discharge rate Q = 12 kg / h 3) Extruder barrel inner diameter D = 25 mm 4) L / L when extruder length is L (mm) D = 475 5) Screw rotation speed N = 280 rpm A sheet having a thickness of 2 mm was formed at 200 ° C. from the composition thus obtained using a T-die extruder, and various evaluations were made. The results are shown in Table 3.

According to Table 3, the combined use of a decomposable / crosslinked thermoplastic resin as (B) not only stabilizes the melt viscosity and improves the extrusion stability, but also improves the mechanical properties,
It can be seen that the appearance is also improved.

[0116]

[Table 3]

Examples 12 to 25 In Example 5, (A) was a hydrogenated rubber, TP
The same experiment was repeated, except that E-2 and TPE-3 were changed. The results are shown in Table 4.

According to Table 4, as (A), ethylene produced using a metallocene catalyst and α having 3 to 20 carbon atoms were used.
-50% or more of the total double bonds of an unsaturated rubber consisting of an ethylene / α-olefin copolymer comprising an olefin and / or a homopolymer having a double bond in a main chain and a side chain and / or a random copolymer. It can be seen that, when a hydrogenated rubber obtained by hydrogenating is used, it is excellent in tensile breaking strength, appearance, flexibility, and scratch resistance.

[0119]

[Table 4]

Examples 26 to 35 In Example 5, the melting temperature T _{2 was determined} according to the following definition.
(° C.), melt-kneading first, then melting temperature T ₃ (° C.)
, And the same experiment was repeated except that instead of DVB, (C-2) and (C-3) shown in Table 5 were changed. Table 5 shows the results. In addition, (C-
2) When (C-3) was used in combination, both were used in equal amounts. According to Table 5, it can be seen that the production under the following melting conditions improves the tensile strength at break, appearance, flexibility, and scratch resistance.

T ₁ : 1 minute half-life temperature (° C.) of (C-1) T ₁ -100 <T ₂ <T ₁ +40 T ₂ +1 <T ₃ <T ₂ +200

[0122]

[Table 5]

Examples 36 to 38 The same experiment as in Example 5 was repeated except that the kneading degree was changed according to the following definition. Table 6 shows the results.
It was shown to. ^{M = (π 2/2)} (L / D) D 3 (N / Q)

Here, L: extruder length (mm) in the die direction based on the raw material addition section, D: extruder barrel inner diameter (m
m), Q: discharge rate (kg / h), N: screw rotation speed (rpm), D = 25 mm, L / D = 47

According to Table 6, 10 × 10 ⁶ ≦ M ≦ 100
It can be seen that the production at a kneading degree M of 0 × 10 ⁶ improves the tensile strength at break, appearance, flexibility, and scratch resistance.

[0126]

[Table 6]

Examples 39 to 58 The same experiment as in Example 5 was repeated except that (A) and (B) described in Table 7 were used, and the wear resistance was evaluated.
Table 7 shows the results. Table 7 shows that the use of a crosslinkable rubber-like polymer using a metallocene catalyst improves wear resistance.

[0128]

[Table 7]

Examples 59 to 67 The same experiments as in Example 5 were repeated except that (A) and (B) shown in Table 8 were changed, or the addition method of (B) was changed. Table 8 shows the results.

In Examples 59 to 67, as in the examples and comparative examples in Tables 1 to 7, except for MO, they were collectively blended and melt-extruded. In Examples 61 to 63, (A) )
(C) After producing a crosslinked product with (D) and a part of (B-1) or (B-2), the remaining (B-1) or (B-2)
-2) was mixed with the above crosslinked product and melt-extruded. According to Table 7, it can be seen that when (B-1) and (B-2) are present at the same time, it is preferable to crosslink (A) with the crosslinker (C).

[0131]

[Table 8]

[0132]

The thermoplastic rubber composition of the present invention has an appearance,
It has excellent flexibility (tactile sensation) and mechanical strength, and can stabilize quality in order to improve productivity. The composition of the present invention can be used for automotive parts, automotive interior materials, airbag covers, mechanical parts, electrical parts, cables, hoses, belts, toys, miscellaneous goods, daily necessities, building materials, sheets, films, and other applications. It can be used widely and plays a large role in the industrial world.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in torque (kgm) by a Labo Plastomill of Reference Examples 1 to 5.

FIG. 2 shows P in component (B) of Example 1 and Comparative Examples 1 and 2.
It is the figure which showed the relationship between the composition ratio of P-1 / EP-1 and the decomposition rate of (B).

FIG. 3 is a diagram showing changes in torque (kgm) and temperature (° C.) by the Labo Plastomill of Example 2 and Comparative Example 3. The solid line shows Example 2 and the dotted line shows Comparative Example 3.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/12 C08L 23/12 23/14 23/14 23/16 23/16 25/04 25/04 53 / 00 53/00

Claims (9)

[Claims] 1. A composition comprising (A) 1 to 99 parts by weight of a crosslinkable rubbery polymer and (B) 1 to 99 parts by weight of a polypropylene resin [total amount of (A) and (B) is 100 parts by weight]. A crosslinked thermoplastic rubber composition, wherein (B) is
In a melting test of the (B) in the presence of an organic peroxide (at a temperature of 200 ° C.), it has a property that a torque higher than M ₀ exists immediately after melting with respect to a torque M ₀ immediately after complete melting. a polypropylene resin (B-1), thermoplastic rubber composition characterized by consisting of a polypropylene resin (B-2) having properties in the M ₀ following torque state since immediately after melting. 2. The thermoplastic rubber composition according to claim 1, wherein (A) is a styrenic and / or olefinic rubbery polymer. 3. (A) is ethylene and α having 3 to 20 carbon atoms.
3. The thermoplastic rubber composition according to claim 2, comprising an ethylene / α-olefin copolymer with an olefin. 4. The thermoplastic rubber composition according to claim 3, wherein (A) is an ethylene / α-olefin copolymer produced using a metallocene catalyst. 5. The heat according to claim 1, wherein (B-1) is a polypropylene random copolymer resin, and (B-2) is a polypropylene block copolymer resin or a polypropylene resin. Plastic rubber composition. 6. (B-1) has a flexural modulus of 100 to 10000 kgf / cm ² according to JIS K6758, and has a differential scanning calorimetry (DSC) of 100.
2. An endothermic peak exists in a temperature range of from -150 [deg.] C., and the endothermic peak calorie is in a range of from 10 to 600 J / g.
6. The thermoplastic rubber composition according to any one of items 5 to 5. 7. (A) 1 to 99 parts by weight of an ethylene / α-olefin copolymer rubber of ethylene and an α-olefin having 3 to 20 carbon atoms produced using a metallocene catalyst, and (B) a polyolefin-based rubber A crosslinked thermoplastic rubber composition comprising 1 to 99 parts by weight of a resin [the total amount of (A) and (B) is 100 parts by weight], wherein (B) is
In a melting test of the (B) in the presence of an organic peroxide (at a temperature of 200 ° C.), it has a property that a torque higher than M ₀ exists immediately after melting with respect to a torque M ₀ immediately after complete melting. the polyolefin resin (B-1), thermoplastic rubber composition characterized by consisting of a polyolefin resin (B-2) having properties in the M ₀ following torque state since immediately after melting. 8. (B-1) is a polyethylene resin and / or
The thermoplastic rubber composition according to claim 7, wherein the thermoplastic rubber composition is a polyolefin resin composed of an α-olefin having 4 to 20 carbon atoms, and (B-2) is a polypropylene block copolymer resin or a polypropylene resin. 9. The method according to claim 1, wherein (A), (B-1) and (B-2) are mixed and crosslinked with (C) a crosslinking agent.
9. The thermoplastic rubber composition according to any one of 8 above.