JP2002348413A - High-strength thermoplastic rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-strength thermoplastic rubber composition that is superior in a bleed resistance, appearance, touch, wear resistance and oil resistance. SOLUTION: In the rubber composition consisting of (A) a cross linking rubber-like polymer and (B) a thermoplastic resin, cross linked partially or totally, the thermoplastic rubber composition with the polymer ratio of the polystyrene-converted molecular weight of 150,000 or less being 30% or less is provided.

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 high-strength thermoplastic rubber composition excellent in not only mechanical strength but also bleed resistance, appearance, feel, abrasion resistance, and oil 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 the olefin-based elastomer, ethylene-propylene-diene rubber (EPDM) or an olefin-based elastomer produced with a metallocene catalyst (JP-A-8-12)
0127, JP-A-9-137001) are known. However, the above composition does not always have sufficient appearance and mechanical strength, and a rubber composition that can withstand practical use is required.

[0003]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention has no such problems as described above, namely, mechanical strength, bleeding resistance, appearance, flexibility (feel), and abrasion resistance. ,
Another object of the present invention is to provide a high-strength thermoplastic rubber composition having excellent oil resistance.

[0004]

Means for Solving the Problems The present inventors diligently studied a thermoplastic rubber composition having excellent appearance and mechanical strength, and found that the crosslinkable rubber-like polymer has a specific molecular weight distribution. It has been found that not only mechanical strength and appearance, but also feel, abrasion resistance and oil resistance are remarkably improved, and the present invention has been completed. That is, the present invention provides: (A) Crosslinkable rubbery polymer and (B)
In a partially or completely crosslinked rubber composition composed of a thermoplastic resin, the proportion of the polymer having a polystyrene equivalent molecular weight of 150,000 or less in the crosslinked rubbery polymer (A) is 30% or less. 1. a thermoplastic rubber composition, (A) The crosslinkable rubbery polymer is composed of ethylene and 3 carbon atoms.
Fully double bond of an unsaturated rubber composed of an ethylene / α-olefin copolymer containing α-olefins of from 20 to 20 or a homopolymer and / or copolymer having a double bond in a main chain and a side chain 2. The thermoplastic rubber composition according to the above 1, wherein 50% or more of the thermoplastic rubber composition is one or more crosslinkable rubbery polymers selected from hydrogenated hydrogenated rubbers. (B) The thermoplastic rubber composition according to the above 1 or 2, wherein the thermoplastic resin is an olefin-based resin, and (C) The thermoplastic rubber composition according to any one of (1) to (3), wherein the thermoplastic rubber composition is cross-linked with a cross-linking agent and further added with (D) a softening agent.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The composition of the present invention has a specific rubber form,
A partially or completely crosslinked rubber composition comprising (A) a crosslinkable rubbery polymer and (B) a thermoplastic resin.
The polystyrene equivalent molecular weight in (A) is 1
It is necessary that the proportion of the polymer of 50,000 or less is 30% or less. The proportion is preferably at most 25%, more preferably at most 20%, most preferably at most 15%, very preferably at most 10%. When the proportion is 30% or less, the crosslinking property is significantly increased, and the mechanical strength, appearance,
Improved feel, abrasion resistance, and oil resistance. The above ratio is 3
If it exceeds 0%, the crosslinkability is significantly reduced.

In the present invention, the crosslinkable rubbery polymer (A) preferably has a glass transition temperature (Tg) of -30 ° C. or lower. Examples of such rubbery polymers include, for example, diene rubbers such as polybutadiene, poly (styrene-butadiene), and poly (acrylonitrile-butadiene), and saturated rubbers obtained by hydrogenating the diene rubbers, isoprene rubbers, and chloroprene rubbers. Rubber, such as polybutyl acrylate, and crosslinked rubber such as ethylene-α-olefin copolymer rubber, ethylene-propylene-diene monomer terpolymer rubber (EPDM), and ethylene-octene copolymer rubber Alternatively, a non-crosslinked rubber and a thermoplastic elastomer containing the above rubber component can be used.

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. 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 particularly preferred are those having 3 to 12 carbon atoms.
And propylene, butene-1, and octene-1 are most preferred. Further, (A) may contain a monomer having an unsaturated bond, if necessary, for example, a conjugated diolefin such as butadiene and isoprene, a non-conjugated diolefin such as 1,4-hexadiene, and dicyclohexane. Cyclic diene compounds such as pentadiene and norbornene derivatives, and acetylenes are preferred, and ethylidene norbornene (ENB) and dicyclopentadiene (DCP) are most preferred.

The ethylene / α-olefin copolymer (A) preferably used in the present invention is preferably produced using a known metallocene catalyst. Generally, 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 polymer yield than a Ziegler-based catalyst. Has a narrow molecular weight distribution, and the distribution of the comonomer α-olefin having 3 to 20 carbon atoms in the copolymer is uniform.

(A) Ethylene used in the present invention
Α-olefin copolymer is α-olefin copolymer
The ratio is preferably from 1 to 60% by weight, more preferably
10 to 50% by weight, most preferably 20 to 45 weight
%. α-olefin copolymerization ratio is 60% by weight
If the ratio exceeds the range, the hardness, tensile strength, etc. of the composition are greatly reduced.
On the other hand, if it is less than 1% by weight, flexibility and mechanical strength are reduced.
I do. (A) Density of ethylene / α-olefin copolymer
Is 0.8-0.9 g / cm ^ThreePreferably in the range of
New Olefin elastomers with densities in this range
By using an
A stoma 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 (1
A range of 90 ° C. and a load of 2.16 kg) is preferably used, and more preferably 0.2 to 10 g / 10 min. If the amount exceeds 100 g / 10 minutes, the crosslinkability of the composition will be insufficient, and if it is less than 0.01 g / 10 minutes, the fluidity will be poor and the processability will be undesirably reduced.

(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, among the preferred crosslinkable rubber-like polymers in (A), there is a thermoplastic elastomer, and among them, a polystyrene-based thermoplastic elastomer is particularly preferred, and a block comprising an aromatic vinyl unit and a conjugated diene unit is preferred. Copolymers and block copolymers in which the conjugated diene unit is partially hydrogenated or epoxy-modified are mentioned.

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, the conjugated diene monomer constituting the block copolymer,
Examples thereof 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 block composed of a conjugated diene and / or a partially hydrogenated unit thereof is represented by B. When displaying with,
SB, S (BS) n (where n is an integer of 1 to 3),
S (BSB) n (where n is an integer of 1 to 2) linear block copolymer or (SB) n X (where n is an integer of 3 to 6; X is silicon tetrachloride, tetrachloride And a coupling agent residue such as tin or polyepoxy compound.
It is preferably a star block copolymer having a portion as a bonding center. Among them, a type 2 linear block copolymer of SB, type 3 of SBS and type 4 of SBSB are preferred.

In the present invention, another preferred hydrogenated copolymer (A) is a polymer having a double bond in a main chain and a side chain and / or an unsaturated rubber comprising a copolymer. More than 50% of the double bonds are hydrogenated rubber. The full double bond in the hydrogenated rubber is
When 50% or more is hydrogenated, preferably 90% or more, and more preferably 95% or more is hydrogenated, 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. Preferably, there is. Specific examples of such rubbers include polybutadiene, poly (styrene-butadiene),
Rubbery polymers obtained by partially or completely hydrogenating diene rubbers such as poly (acrylonitrile-butadiene), polyisoprene, and polychloroprene;
Particularly, a hydrogenated butadiene rubber or a hydrogenated isoprene rubber is 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) .Method of hydrogenation using triisobutylborane catalyst described in Hung Yu Chen, J. Polym. Sci. Polym.
Hydrogenation using toluenesulfonyl hydrazide described in Letter Ed., 15, 271 (1977), or an organic cobalt-organoaluminum catalyst or an organic nickel-organoaluminum catalyst described in JP-B-42-8704. And a method of hydrogenation. Here, a particularly preferred hydrogenation method is described in JP-A-59-133203 and JP-A-60-2201, which use a catalyst capable of hydrogenation under mild conditions of low temperature and low pressure.
No. 47, or hydrogen in an inert organic solvent in the presence of a catalyst comprising a bis (cyclopentadienyl) titanium compound and a hydrocarbon compound having a sodium, potassium, rubidium or cesium atom. This is a method disclosed in JP-A-62-207303.

The Mooney viscosity (ML) of the hydrogenated rubber measured at 100.degree.
The weight% styrene solution viscosity (5% SV) is 0.02-
It is preferably in the range of 0.3 (Pa · sec).
A particularly preferable range is 0.025 to 0.15 (Pa · se).
c). 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. 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. In the present invention, as a method for controlling the proportion of the polymer having a molecular weight in terms of polystyrene of 150,000 or less in (A) the crosslinkable rubbery polymer, a portion having a molecular weight of 150,000 or less is controlled to 30.
%, A method of removing a portion having a molecular weight of 150,000 or less by an operation such as extraction, or a polymerization method in which a molecular weight of 150,000 or less is not selectively produced by a polymerization catalyst or the like. Can be

In the present invention, (B) the thermoplastic resin comprises:
There is no particular limitation as long as it can be uniformly dispersed with (A). For example, a polyaromatic vinyl type, a polyphenylene ether type, a polyolefin type, a polyvinyl chloride type, a polyamide type, a polyester type, a polyphenylene sulfide type, a polycarbonate type, a polymethacrylate type alone or a mixture of two or more types are used. be able to. Particularly, as the thermoplastic resin, an olefin-based resin such as an ethylene-based resin or a propylene-based resin is preferable, and a propylene-based resin is particularly preferable.

Specific examples of the propylene resin most preferably used in the present invention include homo isotactic polypropylene, syndiotactic polypropylene, propylene and ethylene, butene-1, pentene-1, hexene-1 and the like. And other isotactic copolymer resins (including block and random) with other α-olefins. In the present invention, among the components (B), (B-1)
Most preferred is a combination of a propylene random copolymer resin such as a random copolymer resin of ethylene and propylene with (B-2) a propylene block copolymer resin or a homopolypropylene resin. The appearance and mechanical strength are further improved by combining such two types of olefin resins, such as a crosslinked olefin resin and a decomposed olefin resin.

As (B-1), for example, a random copolymer resin of ethylene and propylene can be mentioned. When an ethylene component is present in the polymer main chain, it becomes a crosslinking point of a crosslinking reaction, and This shows the characteristics of the base resin. (B-2) is mainly composed of α-olefin,
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, such as a propylene-based block copolymer resin, it exhibits the properties of a decomposable olefin-based resin.

(B) shows a plurality of (B-1) and (B-2)
A combination of components may be used. Further, the melt index of the olefin resin suitably used in the present invention,
Those having a range of 0.1 to 100 g / 10 minutes (230 ° C., 2.16 kg load) are preferably used. 100g / 1
If it exceeds 0 minutes, the heat resistance and mechanical strength of the thermoplastic elastomer composition will be insufficient, and if it is less than 0.1 g / 10 minutes, the fluidity will be poor and the moldability will decrease, which is not desirable.

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 partially or completely crosslinked rubber composition of the present invention is preferably crosslinked with (C) a crosslinking agent. The component (C) contains (C-1) a crosslinking initiator as an essential component, and optionally contains (C-2) a polyfunctional monomer and (C-3) 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, per 100 parts by weight of the composition comprising (A) and (B).
Used in parts by weight. If the amount is less than 0.01 part by weight, crosslinking is insufficient, and if it exceeds 10 parts by weight, the appearance and mechanical strength of the composition are reduced.

Here, examples of the (C-1) crosslinking initiator include radical initiators such as organic peroxides and organic azo compounds. Specific examples thereof include 1,1-bis (t-butylperoxy) -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-
Peroxy ketals such as 4,4-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-
Dialkyl peroxides such as dimethyl-2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3; acetyl peroxide, isobutylene Luper oxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5
Diacyl peroxides such as trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and m-trioil peroxide; t-butylperoxyacetate, t-butylperoxyisobutyrate, t -Butyl peroxy-2-ethylhexanoate, t-butyl peroxy laurate, t-butyl peroxy benzoate, di-t-butyl peroxy isophthalate, 2,
Peroxyesters such as 5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and cumylperoxyoctate; and t-butyl Hydroperoxides such as hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide and 1,1,3,3-tetramethylbutyl peroxide Can be mentioned.

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 component (C-1) is preferably 1 to 80% by weight, more preferably 10 to 10% by weight of the component (C).
An amount of 50% by weight 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 (C-2) polyfunctional monomers of the (C) crosslinking agent 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 in combination with the component (C-3), particularly when the functional group has three or more functional groups. 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-
Phenylene bismaleimide, 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.

(C-2) is preferably 1 to 80% by weight, more preferably 10 to 50% by weight in the component (C).
Is used. If it is less than 1% by weight, the crosslinking is insufficient, and if it exceeds 80% by weight, the mechanical strength tends to decrease. The monofunctional monomer (C-3) used in the present invention is a vinyl monomer added for controlling a crosslinking reaction rate, and is preferably a radical polymerizable vinyl monomer, and is preferably an aromatic vinyl monomer. Monomers, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, acrylic acid ester monomers, methacrylic acid ester monomers, acrylic acid monomers, methacrylic acid monomers, maleic anhydride monomers 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 it is less than 1% by weight, the crosslinking is insufficient, and if it exceeds 80% by weight, the mechanical strength tends to decrease. The (D) softener is preferably a process oil such as a paraffinic or naphthenic oil. These are used for adjusting the hardness and flexibility of the composition in a proportion of 5 to 500 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the composition comprising (A) and (B). . If the amount is less than 5 parts by weight, flexibility and workability are insufficient, and if it exceeds 500 parts by weight, oil bleed becomes remarkable, which is not desirable.

The particle size of the rubbery polymer in the present invention is controlled by the type and amount of the crosslinking initiator and crosslinking aid, the amount added, the reaction temperature and the reaction system. Are small particles, and uniform particles (i.e., approximate the ratio between the particle diameter d ₁ and the particle minor diameter d ₂ to 1) in order to be the important that under high shear forces, and to suppress the crosslinking rate It is. 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, use of an excessively active crosslinking initiator and a crosslinking aid, or high-temperature reaction conditions cause aggregation of the rubbery polymer and do not satisfy the requirements of the present application. By adding a crosslinking initiator and a crosslinking assistant to the component (A) while preliminarily absorbing a small amount of the softening agent (A) into the component (A), the crosslinking reaction proceeds gently, so that the particles are uniform with small particles. Particles can be generated.

The composition of the present invention is obtained by combining (A) a crosslinkable rubber-like polymer, (B) a thermoplastic resin, and (D) a softener in a specific composition ratio as described above, so that the composition has a high mechanical strength. The balance between flexibility and processability is improved, and it can be preferably used. Further, the composition of the present invention can contain an inorganic filler and / or a plasticizer to such an extent that its characteristics are not impaired. Examples of the inorganic filler used here include calcium carbonate, magnesium carbonate, silica, carbon black, glass fiber, titanium oxide, clay, mica, 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 stabilizer, antioxidant, ultraviolet absorber, light stabilizer, flame retardant, silicone oil, anti-blocking agent, foaming agent,
Antistatic agents, antibacterial agents and the like are also preferably used.

For the production of the composition of the present invention, general methods such as a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder and the like 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 is preferably used as a 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)
And (D) a softening agent is added and the mixture is melt-kneaded to make the cross-linking reaction and kneading dispersion sufficient, and then the mixture is removed from the extruder to obtain pellets of the composition of the present invention. it can.

A particularly preferred melt extrusion method is to have a length L in the die direction with respect to the raw material addition portion,
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 supply part, and the length of the kneading part is 3D to 10D, respectively.

One of the twin-screw extruders 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. Even in the case where a larger kneading is required, a co-rotating / completely meshing screw is preferable.

In the method for producing the composition of the present invention, it is more preferable that the following kneading degree is satisfied. ^{M = (π 2/2)} (L / D) D 3 (N / Q) 10 × 10 6 ≦ M ≦ 1000 × 10 6 where, M: kneading degree, L: extrusion die direction feedstock added portion as a base point Machine length (mm), D: extruder barrel inner diameter (m
m), Q: discharge amount (kg / h), N: screw rotation speed (rpm) kneading degree ^{M = (π 2/2)} (L / D) D 3 (N / Q) is 10
It is important that × 10 ⁶ ≦ M ≦ 1000 × 10 ⁶ . When M is less than 10 × 10 ⁶ , the appearance is deteriorated due to enlargement and aggregation of the rubber particles, while M is 1000 × 10 ⁶
Is exceeded, the mechanical strength decreases due to excessive shearing force.

In order to achieve better appearance and mechanical strength, it is preferable to satisfy the following relational expression. That is, when T ₁ is the half-life temperature (° C.) for one minute of (C), first, melt kneading is performed at the following melting temperature T ₂ (° C.), and then melt kneading is performed at the melting temperature T ₃ (° C.).
In particular, in a melt extruder having a length L in the die direction with respect to the raw material addition port, 0.1 L to 0.1 L from the raw material addition port.
The extruder zone having a length of 5 L is first melt-kneaded at a melting temperature T ₂ (° C.), and then the subsequent extruder zone is melt-kneaded at a melting temperature T ₃ (° C.).

Here, T ₁ is preferably in the range of 150 to 250 ° C., and T ₁ or T _{2 in} each zone of the melt extruder may be a uniform temperature or 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 obtained by any molding method. Manufacture of various molded products is possible. Injection molding, extrusion molding, compression molding, blow molding, calender molding, foam molding and the like are preferably used.

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) Molecular Weight The molecular weight is not particularly limited with respect to the GPC apparatus and the measuring method, but the present inventors used the following apparatus and measuring method. 1. Equipment Waters 150C GPC 2. 2. One column SHOdex AT-807S 1 Tosoh TSK-GEL GMH-H6 2 3 in total Solvent 1,2,4-trichlorobenzene 4. Measurement temperature 140 ° C 5. Standard substance polystyrene having a peak in the molecular weight distribution is a change curve with respect to the base line in GPC measurement, and includes both a broad curve and a sharp curve. The number of peaks is defined by the number of junctions between the tangent parallel to the baseline and the curve. The weight average molecular weight of the peak is the peak top of the GPC curve, and refers to the weight average molecular weight at the intersection of the curve and a tangent drawn in a straight line parallel to the base line.

(2) Bleed resistance The molded article surface was observed and evaluated after being left in an atmosphere of 120 ° C. for 100 hours. A: Very good. ：: good △: slightly oily substance adhered to the surface of the molded product. ×: A large amount of oily substance adhered to the surface of the molded product, and the stickiness was remarkable.

(3) Wear Resistance Evaluation was performed using a Gakushin type wear tester. The evaluation conditions are as follows. Temperature condition: 23 ° C atmosphere Stroke: 120 mm Frequency: 1 reciprocal / 2 seconds Load: 200 g 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

(4) Feeling In a 23 ° C. atmosphere, the touch was actually touched with a hand to evaluate the dry feeling (no stickiness) and whether or not a fingerprint mark remains on the surface of the molded product. A: The feel is extremely good and smooth, and no fingerprint is left. ：: Fingerprint marks remain on the surface of the molded product, but no stickiness is felt. ×: Fingerprint marks remain, and there is a sticky feeling and a slimy feeling.

(5) Appearance of Injection Molded Article The appearance of the injection molded article was evaluated according to the following criteria. ◎ Very good ○ Good △ Good, but some aggregates are observed. × Agglomerates overall, no gloss

(6) Oil resistance Weight W of a composition sheet having a thickness of 2 mm in advance₀Measure
After that, the composition sheet was placed in liquid paraffin at 80 ° C. for 2 hours.
After standing for 0 hours, the weight of the composition sheet (W ₁)
And calculate the weight change rate as follows. Where the number
The smaller the value, the better the oil resistance. Weight change rate = (W₁-W₀) / W₀× 100 (%) (7) Tensile breaking strength (MPa) According to JIS K6251, 2
The evaluation was performed at 3 ° C. (8) Analysis of conjugated diene rubber 1) Hydrogenation rate (%) It was measured by NMR according to the following procedure.

First, the polybutadiene rubber before hydrogenation was dissolved in deuterated chloroform, and FT-NMR (270 Meg.,
Proton (= CH-) by 1,2-vinyl of JEOL) at chemical shifts 4.7～5.2Ppm (the signal C _0), the chemical shift 5.2～5.8Ppm (signal D ₀ ) Was calculated from the integrated intensity of the vinyl proton (= CH ₂ ) in the following formula. (V) = _{[0.5C 0 /{0.5C 0 +0.5 (D 0} -0.5
C ₀ )｝] × 100 Next, the polybutadiene rubber after the 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 A ₁ ) the added 1,2 bonds with methyl group protons (-CH ₃₎ chemical shifts 4.7～5.2Ppm (the signal C ₁₎ of the hydrogenated non 1,2-vinyl by proton (= CH ₂₎ It was calculated from the integrated intensity of chemical shift 5.2～5.8Ppm (the signal D ₁₎ of the hydrogenated non-vinyl proton (= CH-) by the following equation.

First, p = 0.5C ₀ /(0.5C ₁ + A ₁ /
3) Let A ₁₁ = pA ₁ , C ₁₁ = pC ₁ , D ₁₁ = pD _1, and 1,2-
Hydrogenation ratio of the vinyl bond moiety (B) (B) = _{[(A 11/3) / {} A 11/3 + C 11/2} ] ×
100 Hydrogenation rate of 1,4-double bond part (C) (C) = [｛0.5 (D ₀ −0.5C ₀ ) −0.5 (D ₁₁ −
0.5C ₁₁ )｝ / 0.5 (D ₀ -0.5 C ₀ )] × 100 Hydrogenation rate of the entire 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-vinyl bond after == (V) × {100- (B)} / 100 (%) 1,4-bond after hydrogenation = {100- (V)} × {100- (B)} / 100 (%) The following components were used in Examples and Comparative Examples.

(A) Rubbery Polymer The ratio of the following polymer having a molecular weight in terms of polystyrene of 150,000 or less in the rubbery polymer is increased by changing the polymerization initiator amount and the temperature to increase the overall molecular weight. By decreasing or decreasing the molecular weight, a portion having a molecular weight of 150,000 or less was controlled. 1) Copolymer of ethylene and octene-1 (TPE-
1) It was prepared by a method using a metallocene catalyst described in JP-A-3-1630088. The composition ratio of ethylene / octene-1 in the copolymer is 72/28 (weight ratio).
(Referred to as TPE-1) 2) Copolymer of ethylene and octene-1 (TPE-
2) It was manufactured by a method using a usual Ziegler catalyst. The ethylene / octene-1 composition ratio of the copolymer is 72/2.
8 (weight ratio). (Referred to as TPE-2) 3) Ethylene propylene ethylidene norbornene (ENB) copolymer (TPE-3) Produced by a method using a metallocene catalyst described in JP-A-3-16388. The composition ratio of ethylene / propylene / ENB in the copolymer is 72/24/4 (weight ratio). (Referred to as TPE-3)

(B) Thermoplastic resin 1) Polypropylene (PP) Nippon Polyolefin Co., Ltd., isotactic homopolypropylene (PP) 2) Polystyrene (PS) Asahi Kasei Corp. (PS) 3 ) Polystyrene / acrylonitrile (AS) Acrylonitrile / styrene (25 / manufactured by Asahi Kasei Corporation)
4) Hydrogenated styrene / butadiene block copolymer (SEBS) manufactured by Asahi Kasei Corporation (referred to as SEBS)

(C) Crosslinking agent 1) Crosslinking initiator (C-1) 2,5-dimethyl-2,5-bis (t-manufactured by NOF Corporation)
Butylperoxy) hexane (Product 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)
Butylperoxy) hexine-3 (trade name: perhexin 25B) (referred to as POX-2) 3) Polyfunctional monomer (C-2) manufactured by Wako Pure Chemical Industries, Ltd., divinylbenzene (referred to as DVB) 4) Multiplicity Functional monomer (C-2) Nippon Kasei Co., Ltd., triallyl isocyanurate (TA
5) Polyfunctional 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 (MMA) (d) Paraffin oil Idemitsu Kosan Co., Ltd., Diana Process Oil PW-9
0 (referred to as MO)

[0050]

Examples 1 to 5 and Comparative Examples 1 to 3 A twin-screw extruder (25) consisting of 11 blocks having an inlet at the center of the barrel.
mmφ, L / D = 47), (A) TPE-1 / (B) PP
/ (C-1) POX-1 / (C-2) TAIC / (D) MO = 70 /
The composition consisting of 30 / 0.5 / 1.0 / 40 (weight ratio) 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. (Standard melting conditions) 1) Melt extrusion temperature 250 ° C. constant 2) Discharge rate Q = 12 kg / h 3) Extruder barrel inner diameter D = 25 mm 4) L / D = 47 when extruder length is L (mm) 5) Screw rotation speed N = 280 rpm From the elastomer composition thus obtained, 200
A sheet having a thickness of 2 mm was prepared by injection molding at ℃, and each characteristic was evaluated. The results are shown in Table 1. Table 1 shows that when the requirements of the present invention are satisfied, the mechanical strength, bleed resistance, appearance, feel, abrasion resistance, and oil resistance of the injection molded product are excellent.

[0051]

[Table 1]

[0052]

Examples 6 to 17 In Example 1, (A)
Hydrogenated rubber, TPE-2, or TPE-3 in which the proportion of a polymer having a polystyrene equivalent molecular weight of 150,000 or less accounts for 20%.
A similar experiment was repeated, except that was used. The results are shown in Table 2. According to Table 2, as (A), ethylene produced using a metallocene catalyst and C3 to C2 were used.
Full-duplex of an ethylene / α-olefin copolymer comprising an α-olefin of 0 and / or a homopolymer having a double bond in a main chain and a side chain, and / or an unsaturated rubber comprising a random copolymer When a hydrogenated rubber in which 50% or more of the bond is hydrogenated is used, it is found that the bleeding resistance, the appearance, the feel, the abrasion resistance, and the oil resistance of the injection molded product are excellent.

[0053]

[Table 2]

[0054]

Examples 18 to 23 In Example 3, (C-1) and (C-2) were replaced with (C-1) and (C-
The same experiment was repeated, except that 2) and (C-3) were changed. Table 3 shows the results. In addition, (C-
When 2) and (C-3) were used in combination, both were used in equal amounts. Table 3 shows that when TAIC is used as (C-2), bleed resistance is particularly excellent.

[0055]

[Table 3]

[0056]

Examples 24 to 27 In Example 1, as (A), TPE-1 in which the ratio of a polymer having a molecular weight in terms of polystyrene of 150,000 or less was 23% was used, and (B) was used.
Was changed to the thermoplastic resin shown in Table 4, and the same experiment was repeated. Table 4 shows the results.

[0057]

[Table 4]

[0058]

The thermoplastic rubber composition of the present invention is excellent in mechanical strength, bleed resistance, appearance, feel, abrasion resistance and oil resistance. The thermoplastic rubber composition of the present invention includes automobile parts, automobile interior materials, airbag covers, mechanical parts, electric parts, cables, hoses, belts, toys, miscellaneous goods, daily necessities, building materials, sheets, films and the like. It can be widely used for various applications, and plays a large role in the industrial world.

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Claims (4)

[Claims] 1. A partially or completely crosslinked rubber composition comprising (A) a crosslinkable rubbery polymer and (B) a thermoplastic resin, wherein (A) the crosslinkable rubbery polymer accounts for A thermoplastic rubber composition, wherein the proportion of the polymer having a polystyrene equivalent molecular weight of 150,000 or less is 30% or less. 2. The crosslinkable rubbery polymer (A) is an ethylene / α-olefin copolymer containing ethylene and an α-olefin having 3 to 20 carbon atoms, or a double bond in a main chain and a side chain. 2. An unsaturated rubber comprising a homopolymer and / or a copolymer, wherein at least 50% of all double bonds are hydrogenated hydrogenated rubbers and at least one crosslinkable rubbery polymer. 5. The thermoplastic rubber composition according to item 1. 3. The thermoplastic rubber composition according to claim 1, wherein (B) the thermoplastic resin is an olefin resin. 4. The thermoplastic rubber composition according to claim 1, wherein the thermoplastic rubber composition is crosslinked with a crosslinking agent (C) and further added with a softening agent (D).