JP2006328307A - Injection molded body - Google Patents

Abstract

The present invention provides an injection molded article excellent in injection moldability obtained from a crosslinked rubber composition having excellent continuous productivity.
SOLUTION: (A) Crosslinkable rubbery polymer such as ethylene / α-olefin copolymer produced using metallocene catalyst, (B) Olefin resin such as propylene resin, (C) Branched olefin Injection molded body of a crosslinked rubber composition comprising an extensional viscosity improver selected from an epoxy resin, a fluororesin, a polyester resin and a polyamide resin, in particular, (C) is fiberized, and further, An injection-molded article of a rubber composition, which may be crosslinked.
[Selection figure] None

Description

  The present invention relates to an injection molded body. More specifically, the present invention relates to an injection molded article excellent in injection moldability obtained from a crosslinked rubber composition having excellent continuous productivity.

Conventionally, injection molded articles have been widely used as home appliance parts, automobile exterior parts, housing / building material parts, and the like. However, a soft injection-molded product is soft and good, but has a low mechanical strength. On the other hand, a hard injection-molded product has a problem of insufficient touch (flexibility). For this reason, in addition to the above characteristics, the appearance of an injection molded article having excellent fluidity that can be molded thinly in response to weight reduction is awaited.
As such a rubber composition, a dynamic crosslinking technique using an olefin elastomer (for example, see Patent Documents 1 and 2) produced by ethylene-propylene-diene rubber (EPDM) is known. When the composition is pelletized by the strand method because the melt viscosity is lowered with the improvement of the properties, it becomes difficult to take up the strands, resulting in a problem of inferior continuous productivity.

On the other hand, as a technique for improving viscoelasticity such as foaming characteristics, an olefin-based elastomer blended with acrylic-modified polytetrafluoroethylene (for example, see Patent Document 3), a polyolefin blended with polyalkylene terephthalate or polyalkylene naphthalate (for example, , See Patent Document 4). Although the above composition has improved viscoelasticity such as foaming characteristics, an injection molded product that has poor injection moldability and can withstand practical use is demanded.
JP-A-8-120127 Japanese Patent Laid-Open No. 9-137001 US6787607 B2 publication JP 2005-68217 A

  In view of such a current situation, the present invention is to provide an injection molded article excellent in injection moldability obtained from a crosslinked rubber composition having no such problems as described above, that is, having excellent continuous productivity. It is the purpose.

As a result of intensive investigation of an injection molded product obtained from a crosslinked rubber having excellent continuous productivity, the present inventors have surprisingly found that the use of a crosslinked rubber composition having a specific elongation viscosity improver The inventors have found that continuous productivity can be dramatically improved while maintaining the injection moldability of the composition, and the present invention has been completed.
That is, the present invention relates to an injection-molded product of a crosslinked rubber composition comprising a crosslinkable rubber-like polymer (A), an olefinic resin (B), and an elongational viscosity improver (C). The present invention provides an injection molded article of a rubber composition characterized in that

  The crosslinked rubber composition constituting the injection-molded article of the present invention is excellent in continuous productivity while maintaining injection moldability.

The present invention will be specifically described below.
The injection-molded article of the present invention comprises a crosslinked rubber composition comprising a crosslinkable rubber-like polymer (A), an olefin resin (B), and an extensional viscosity improver (C).
Here, it is important that the component (A) and the component (B) are crosslinked while maintaining thermoplasticity. Crosslinking of the above components improves excellent mechanical properties, particularly rubber properties and durability.
And addition of an extensional viscosity improver (C) is essential. Component (C) is a component for selectively increasing the extensional viscosity while restricting the increase in shear viscosity. In order to improve the injection moldability, it is preferable that the shear viscosity is low. In general, however, in such a case, the extensional viscosity is lowered, and the continuous productivity represented by strand take-up is remarkably lowered. As a mechanism, the present inventors have found that (C) a specific agent is fibrillated during molding, thereby suppressing an increase in shear viscosity and increasing an extensional viscosity, thereby completing the present invention.

Hereinafter, each component of the present invention will be described in detail.
(A) Component In the present invention, (A) the crosslinkable rubber-like polymer is obtained by hydrogenating a diene rubber such as polybutadiene, poly (styrene-butadiene), poly (acrylonitrile-butadiene), and the diene rubber. Saturated polymer rubber (hydrogenated copolymer rubber), isoprene rubber, chloroprene rubber, acrylic rubber such as polybutyl acrylate, ethylene-propylene copolymer, ethylene-octene copolymer, ethylene-propylene-diene monomer Examples thereof include a crosslinked rubber or non-crosslinked rubber such as an ethylene / α-olefin copolymer such as a terpolymer (EPDM), and a thermoplastic elastomer containing the rubber component.

Further, (A) preferably has a glass transition temperature (Tg) of −10 ° C. or lower.
And (A) Mooney viscosity (ML) (ISO 289-1985 (E) conformity) measured at 100 degreeC has preferable 20-150, More preferably, it is 50-120.
In this invention, it is preferable in (A) crosslinkable rubber-like polymer. One of the polymers is an ethylene / α-olefin copolymer, more preferably a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of the α-olefin include propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, and dodecene-1. Etc. Among them, hexene-1, 4-methylpentene-1, and octene-1 are preferable, and an α-olefin having 3 to 12 carbon atoms is particularly preferable, and propylene, butene-1, and octene-1 are most preferable.

Further, (A) the crosslinkable rubber-like polymer can contain a monomer having an unsaturated bond, if necessary, such as conjugated diolefins such as butadiene and isoprene, 1,4-hexadiene and the like. Non-conjugated diolefins, cyclic diene compounds such as dicyclopentadiene and norbornene derivatives, and acetylenes are exemplified. In particular, ethylidene norbornene (ENB) and dicyclopentadiene (DCP) are most preferable.
In the present invention, an ethylene / α-olefin copolymer (hereinafter referred to as “(A) ethylene / α-olefin copolymer)”, which is one of the preferred copolymers of (A), is a known metallocene catalyst. It is preferable to manufacture using.

In general, a metallocene catalyst comprises 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 a polymer obtained in comparison with a Ziegler catalyst. The molecular weight distribution is narrow and the distribution of the α-olefin having 3 to 20 carbon atoms, which is a comonomer in the copolymer, is uniform.
The ethylene / α-olefin copolymer (A) used in the present invention preferably has a copolymerization ratio of α-olefin of 1 to 60% by weight, more preferably 10 to 50% by weight, most preferably. 20 to 45% by weight. The copolymerization ratio of α-olefin is preferably 60% by weight or less from the viewpoints of the hardness and tensile strength of the composition, and is preferably 1% by weight or more from the viewpoints of flexibility and mechanical strength.

The density of the ethylene / α-olefin copolymer (A) is preferably in the range of 0.8 to 0.9 g / cm ³ . By using an ethylene / α-olefin copolymer having a density in this range, the thermoplastic elastomer composition of the present invention having excellent flexibility and low hardness can be obtained.
The ethylene / α-olefin copolymer (A) used in the present invention preferably has long chain branching. Due to the presence of long chain branching, it is possible to make the density smaller compared to the proportion (% by weight) of the α-olefin copolymerized without reducing the mechanical strength. An ethylene / α-olefin copolymer having high hardness and high strength can be obtained. The ethylene / α-olefin copolymer having a long chain branch is described in US Pat. No. 5,278,272.

The ethylene / α-olefin copolymer of (A) desirably has a melting point peak of a thermobalance (DSC) above room temperature. When it has a melting point peak, the form is stable in the temperature range below the melting point, it is easy to handle and has little stickiness.
The melt index of the ethylene / α-olefin copolymer (A) used in the present invention is in the range of 0.01 to 100 g / 10 min (190 ° C., 2.16 kg load (0.212 Pa)). Those are preferably used, and more preferably 0.2 to 10 g / 10 min. From the viewpoint of crosslinkability of the thermoplastic elastomer composition of the present invention, 100 g / 10 min or less is preferable, and from the viewpoint of fluidity and processability, 0.01 g / 10 min or more is preferable.

In the present invention, the hydrogenated copolymer which is another preferred copolymer of (A) is a homopolymer rubber of at least one conjugated diene monomer, or a conjugated diene monomer and an aromatic A copolymer rubber comprising a vinyl monomer, preferably a hydrogenated copolymer rubber in which the hydrogenation rate of the full double bond of the random copolymer is 50% or more, particularly in the main chain and the side chain. A hydrogenated copolymer rubber in which 50% or more of the total olefinic double bonds of the unsaturated polymer rubber comprising a polymer and / or copolymer having a double bond is hydrogenated is preferable.
In the hydrogenated copolymer rubber, if necessary, for example, olefinic, methacrylic ester, acrylic ester, unsaturated nitrile, vinyl chloride monomer and other conjugated dienes can be copolymerized. A monomer (hereinafter referred to as a copolymerizable monomer) can be copolymerized.

Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3- Hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene and the like can be mentioned, and 1,3-butadiene, isoprene and 1,3-pentadiene are preferable, Most preferred are 3-butadiene and isoprene.
Examples of the aromatic vinyl monomer include styrene, α-methyl, t-butylstyrene, divinylbenzene, N, N-dimethyl-p-aminoethylstyrene, vinylpyridine, and the like. -Methylstyrene is preferred. The aromatic monomers can be used alone or in combination of two or more. The aromatic vinyl monomer content is preferably 0 to 80% by weight, more preferably 0 to 50% by weight, and most preferably 0 to 30% by weight.

  In the hydrogenated copolymer as (A), the vinyl bond in the conjugated diene monomer portion before hydrogenation may be present uniformly in the molecule, or may increase or decrease or decrease along the molecular chain. In addition, a plurality of blocks having different vinyl bond contents may be included. When the aromatic vinyl monomer and / or copolymerizable monomer is included, the conjugated diene monomer and the aromatic vinyl monomer and / or copolymerizable monomer are randomly bonded. However, it may contain a block-like aromatic vinyl monomer and / or a block-like copolymerizable monomer. The content of the block-like aromatic vinyl polymer is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total aromatic vinyl monomer.

The total olefinic double bonds in the hydrogenated copolymer rubber are 50% or more, preferably 90% or more, more preferably 95% or more, and the remaining double bonds in the main chain are 5% or less. The residual double bond in the side chain is 5% or less. Specific examples of such hydrogenated copolymer rubbers include partially or completely hydrogenated diene rubbers such as polybutadiene, poly (styrene-butadiene), poly (acrylonitrile-butadiene), polyisoprene, polychloroprene. Examples thereof include rubber-like polymers, and hydrogenated butadiene-based or hydrogenated isoprene-based rubber is particularly preferable.
Such a hydrogenated copolymer rubber can be obtained by partially hydrogenating the above-described diene rubber by a known hydrogenation method. For example, F.A. L. Ramp, etal, J. et al. Amer. Chem. Soc. , 83, 4672 (1961), a method of hydrogenation using a triisobutylborane catalyst, Hung Yu Chen, J. et al. Polym. Sci. Polym. Letter Ed. , 15, 272 (1977), or hydrogenation using an organic cobalt-organic aluminum catalyst or organic nickel-organic aluminum catalyst described in Japanese Patent Publication No. 42-8704. The method etc. can be mentioned.

Here, particularly preferred hydrogenation methods are disclosed in JP-A-59-133203 and JP-A-60-220147 using inert catalysts that can be hydrogenated under mild conditions of low temperature and low pressure, or inert organic compounds. Contacting with hydrogen in a solvent in the presence of a catalyst comprising a bis (cyclopentadienyl) titanium compound and a hydrocarbon compound having a sodium atom, a potassium atom, a rubidium atom or a cesium atom This is the method shown in the gazette.
The hydrogenated copolymer rubber preferably has a 5 wt% styrene solution viscosity (5% SV) at 25 ° C. in the range of 20 to 300 centipoise (cps). A particularly preferred range is 25 to 150 cps.

The hydrogenated copolymer rubber preferably has crystallinity, and the endothermic peak calorific value, which is an index of crystallinity, is controlled by adding a polar compound such as tetrahydrofuran or controlling the polymerization temperature. The reduction of the endothermic peak heat amount is achieved by increasing the amount of polar compound during the production of the rubbery polymer or increasing the 1,2-vinyl bond by decreasing the polymerization temperature.
The (A) crosslinkable rubbery polymer used in the present invention may be used by mixing a plurality of types. In such a case, the workability can be further improved.
In the present invention, the proportion of the polymer having a polystyrene-reduced molecular weight of 150,000 or less in the crosslinkable rubber-like polymer (A) is preferably 30% by weight or less, more preferably 25% or less, and still more preferably. 20% or less, most preferably 15% or less, and most preferably 10% or less. When the ratio is 30% or less, the crosslinkability is remarkably increased, and the mechanical strength, appearance, feel, wear resistance and oil resistance are improved.

In the present invention, as a method for controlling the proportion of the polymer having a polystyrene-reduced molecular weight of 150,000 or less in the crosslinkable rubber-like polymer (A) in the present invention, the entire molecular weight of 150,000 or less is 30% or less. And a method of removing a part 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 generated by a polymerization catalyst or the like.
In the present invention, the degree of crosslinking obtained from the xylene-insoluble matter of (A) is preferably 10% or more, more preferably 30%, and most preferably 70%. When it is within the above range, excellent injection moldability, flexibility and scratch resistance are exhibited.

(B) Component In the present invention, the (B) olefin resin is a copolymer resin containing ethylene or / and α-olefin, such as ethylene or propylene resin, alone or in combination of two or more. In particular, a propylene resin is preferable.
Specific examples of the propylene-based resin most preferably used in the present invention include homoisotactic polypropylene, propylene, and other α-olefins such as ethylene, butene-1, pentene-1, and hexene-1. And isotactic copolymer resins (including blocks and random).

In the present invention, among the components (B), (B-1) a propylene random copolymer resin alone such as a random copolymer resin of ethylene and propylene, which is a cross-linked olefin resin, or (B-1) and ( B-2) A combination with a propylene block copolymer resin or a homopolypropylene resin which is a decomposable olefin resin is preferred. The appearance and mechanical strength are further improved by combining two types of olefin resins, such as a crosslinked olefin resin and a decomposable olefin resin.
Examples of (B-1) include a random copolymer resin of ethylene and propylene. When the ethylene component is present in the polymer main chain, it becomes a cross-linking point of the cross-linking reaction, and Show properties.

(B-2) is mainly composed of an α-olefin, and preferably contains no ethylene unit in the polymer main chain. However, when an ethylene-α olefin copolymer is present as a dispersed phase, such as a propylene block copolymer resin, the characteristics of the decomposable olefin resin are exhibited.
(B) may be a combination of a plurality of components (B-1) and (B-2).
Random copolymer resin with α-olefin mainly composed of propylene among (B-1) can be produced by high pressure method, slurry method, gas phase method, bulk method, solution method, etc. As the catalyst, Ziegler-Natta catalyst, single site, metallocene catalyst is preferable. In particular, when a narrow composition distribution and molecular weight distribution are required, a random copolymerization method using a metallocene catalyst is preferable.

A specific method for producing the random copolymer resin is disclosed in European Patent 096943A or US Pat. No. 5,19841,401, and after introducing liquid propylene into a reactor equipped with a stirrer, the catalyst is added to the gas phase or liquid phase from a nozzle. Next, ethylene gas or α-olefin is introduced into the gas phase or liquid phase of the reactor, and the reaction temperature and reaction pressure are controlled to conditions under which propylene is refluxed. The polymerization rate is controlled by the catalyst concentration and the reaction temperature, and the copolymer composition is controlled by the amount of ethylene or α-olefin added.
Moreover, the thing of the range of 0.1-100 g / 10min (230 degreeC, 2.16kg load (0.212Pa)) is preferably used for the melt index of the olefin resin used suitably by this invention. From the viewpoint of heat resistance and mechanical strength of the thermoplastic elastomer composition, it is preferably 100 g / 10 min or less, and from the viewpoint of fluidity and moldability, 0.1 g / 10 min or more is preferable.

In the present invention, each component in 100 parts by weight of the composition comprising (A) and (B), (A) is preferably 1 to 99% by weight, more preferably 10 to 80% by weight, most preferably 20 to 70% by weight, and (B) is preferably 1 to 99% by weight, more preferably 90 to 20% by weight, and most preferably 80 to 30% by weight. Within the above range, the balance between injection moldability and scratch resistance is improved.
In the present invention, the rubber composition comprising (A) and (B) may be one obtained by melt-mixing separate (A) and (B) with an extruder, or (A) and (B May be a polymerizable olefinic crosslinkable rubber composition produced during polymerization. Such a polymerizable olefinic crosslinkable rubber composition is a thermoplastic elastomer produced by a polymerization method comprising a dispersed phase of an olefinic rubber and a continuous phase of an olefinic resin. Usually, it is produced by a multistage polymerization method.

In the present invention, the multistage polymerization method means a polymerization method in which a plurality of types of polymers can be continuously produced by performing multistage polymerization of two or more stages, instead of completing the polymerization once. However, this method is different from the usual polymer blending method in which a mixed resin composed of different kinds of polymers is obtained using a mechanical method.
The olefinic crosslinkable rubber composition obtained by the multistage polymerization method is a copolymer obtained by multistage polymerization of (1) hard segment and (2) soft segment in a reactor. (1) The hard segment is typically a propylene homopolymer block or a copolymer block of propylene and an α-olefin, such as propylene / ethylene, propylene / 1-butene, propylene / ethylene / 1- Examples include binary or ternary copolymer blocks such as butene. The (2) soft segment is typically an ethylene homopolymer block and a copolymer block of ethylene and α-olefin, such as ethylene / propylene, ethylene / 1-butene, ethylene / propylene / 1-butene. Binary or ternary copolymer blocks such as

(C) Component In the present invention, (C) the extension viscosity improver is a component for selectively increasing the extension viscosity while limiting the increase in shear viscosity, and the mechanism is not clear. As a mechanism, (C) is fiberized during molding, thereby increasing the extensional viscosity while suppressing the increase in shear viscosity. As a result, while maintaining high injection moldability, high continuous productivity represented by strand take-up is manifested.
(C) in the present invention is not particularly limited as long as it is an agent that improves the elongational viscosity, but among them, one or more agents selected from branched olefin resins, fluorine resins, polyester resins, and polyamide resins are preferable.

The branch-containing olefin resin as (C) is preferably a branched structure in a copolymer resin containing ethylene or / and α-olefin alone or in combination of 2 to 20 carbon atoms such as ethylene or propylene resin. In particular, a propylene resin having a branched structure is preferable.
A preferred fluorine-based resin as (C) is a resin containing a fluorine atom in the resin. Specific examples thereof include polymonofluoroethylene, polydifluoroethylene, polytrifluoroethylene, polytetrafluoroethylene, and tetrafluoroethylene / hexafluoropropylene copolymer. Further, if necessary, the above fluorine-containing monomer and a copolymerizable monomer may be used in combination. Of the fluororesins, polytetrafluoroethylene is most preferred.

Methods for producing these fluorine-based resins are disclosed in US Pat. No. 2,393,697 and US Pat. No. 2,534,058. For example, tetrafluoroethylene is converted into ammonium persulfate, persulfate in an aqueous medium. Polymerize under pressure of 7-7 kg / cm ² at a temperature of 0-200 ° C. using a radical initiator such as potassium sulfate and then coagulate from a suspension, dispersion or emulsion, or precipitate Thus, polytetrafluoroethylene powder is obtained.
The fluororesin is preferably subjected to resin modification treatment from the viewpoint of dispersibility. For example, acrylic resin modification is preferred, and it contains a (meth) acrylic acid alkyl ester polymer containing a structural unit consisting of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. Most preferably, the acrylic resin-modified polytetrafluoroethylene disclosed in WO 02/090440 A1 is preferable because it has an extremely high effect of increasing the elongational viscosity while maintaining the shear viscosity.
The polyester-based resin as the preferred (C) is a resin containing an ester bond in the molecule, and in particular, a resin having an ester bond in the main chain is more likely to be fiberized than a side chain, and has a greater effect of improving the extensional viscosity. preferable. Examples of such polyester resins include polyalkylene terephthalates such as polybutylene terephthalate and polyethylene terephthalate, and polyalkylene naphthalates such as polyethylene naphthalate.

(D) Component It is preferable that the composition of this invention is bridge | crosslinked with (D) crosslinking agent.
(D) The crosslinking agent contains (D-1) a crosslinking initiator as an essential component, and contains (D-2) a polyfunctional monomer and (D-3) a monofunctional monomer as necessary. The (D) crosslinking agent is used in an amount of 0.001 to 10 parts by weight, preferably 0.005 to 3 parts by weight, based on 100 parts by weight of the total of (A) and (B). Within the above range, the level of cross-linking is increased, and the balance between the powder fluidity and the mechanical strength of the composition is improved.

  Here, examples of the (D-1) crosslinking initiator include radical initiators such as organic peroxides and organic azo compounds, and 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-4,4-bis (t Peroxyketals such as -butylperoxy) butane and n-butyl-4,4-bis (t-butylperoxy) valerate; di-t-butyl peroxide, dicumyl peroxide, -Butyl cumyl peroxide, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, α, α'-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5 -Dialkyl peroxides such as bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3.

  Acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and diacyl peroxides such as m-trioyl peroxide; t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxylaurate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl Peroxyesters such as carbonate and cumylperoxyoctate; and t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide And hydroperoxides such as 1,1,3,3-tetramethylbutyl peroxide.

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 (D-1) is preferably used in an amount of 1 to 80% by weight, more preferably 10 to 50% by weight in the component (D). 1% by weight or more is preferable from the viewpoint of crosslinkability, and 80% by weight or less is preferable from the viewpoint of mechanical strength.

  In the present invention, the (D) polyfunctional monomer contained in the (D) crosslinking agent as necessary is preferably a radical 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 particularly in the case of having 3 or more functional groups in combination with (D-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-quinonedioxime, P, P'-dibenzoylquinonedioxime, phenylmaleimide, allyl methacrylate, N, N'-m-phenylenebismaleimide, diallyl Phthalate, tetraallyloxyethane, 1,2-polybutadiene and the like are preferably used. Triaryl isocyanurate is particularly preferable. These polyfunctional monomers may be used in combination.

The (D-2) is preferably used in an amount of 1 to 80% by weight, more preferably 10 to 50% by weight in the component (D). 1% by weight or more is preferable from the viewpoint of crosslinkability, and 80% by weight or less is preferable from the viewpoint of mechanical strength.
The (D-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 or acrylonitrile. , Unsaturated nitrile monomers such as methacrylonitrile, ester monomers such as acrylic acid ester monomers and methacrylic acid ester monomers, unsaturated carboxylic acids such as acrylic acid monomers and methacrylic acid monomers Examples thereof include unsaturated carboxylic acid anhydrides such as acid monomers and maleic anhydride monomers, and N-substituted maleimide monomers.

The (D-3) is preferably used in an amount of 1 to 80% by weight, more preferably 10 to 50% by weight in the component (D). 1% by weight or more is preferable from the viewpoint of crosslinkability, and 80% by weight is preferable from the viewpoint of mechanical strength.
In the present invention, the most preferable combination (D) of the crosslinking agent is 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane (trade name Perhexa 25B, manufactured by NOF Corporation as a crosslinking initiator. ) Or 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 manufactured by Nippon Oil & Fats Co., Ltd. and triallyl isocyanurate (TAIC) manufactured by Nippon Kasei Co., Ltd. )) Is excellent in mechanical strength and retainability of the softener when the softener described below is present.

(E) component In this invention, the agent (E) chosen from a softening agent, the powdery compound which does not melt at 250 degreeC, a polyorganosiloxane, a styrene-type thermoplastic elastomer, and a resin-type wax can be contained as needed. .
The softener is preferably a process oil composed of paraffinic, naphthenic, aromatic hydrocarbons. In particular, naphthenic hydrocarbon-based process oils are preferred from the viewpoint of compatibility with paraffinic hydrocarbons or rubber. From the viewpoint of heat and light stability, the aromatic hydrocarbon content in the process oil is preferably 10% or less, more preferably 5% or less, in terms of the carbon number ratio of ASTM D2140-97. Most preferably, it is 1% or less.
These softeners are used in an amount of 5 to 500 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the total of (A) and (B). Within the above range, the balance between injection moldability, flexibility and bleed resistance is excellent.

  In the present invention, (E) the powdery compound that does not melt at 250 ° C., which can be added as necessary, may be organic or inorganic. Specific examples include organic acid metal salts such as fatty acid metal salts, 2,2′-methylenebis (4,6-di-t-butylphenyl) sodium phosphate, bis (p -Methylbenzylidene) sorbitol, bis (p-ethylbenzylidene) sorbitol and the like. Specific examples of the inorganic system include zinc oxide, alumina (aluminum oxide), aluminum silicate, silica (silicon oxide), calcium oxide, calcium carbonate, titanium oxide, iron oxide, barium oxide, manganese dioxide, magnesium oxide, and oxidation. Manganese, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, tin oxide, antimony oxide, nickel oxide, copper oxide, tungsten oxide, etc. or a complex (alloy) thereof, Hydrates of inorganic metal compounds such as aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, zeolite, calcium hydroxide, barium hydroxide, basic magnesium carbonate, zirconium hydroxide, tin oxide hydrate, boron Zinc acid, zinc metaborate, On the other hand barium, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, may be mentioned kaolin, montmorillonite, bentonite, clay, mica, talc and the like, among which a plate-like filler is preferably talc, mica, kaolin is particularly preferred.

The amount of the powdery compound is preferably from 0.1 to 200 parts by weight, more preferably from 1 to 150 parts by weight, and most preferably from 5 to 100 parts per 100 parts by weight of the total of (A) and (B). Part by weight, very preferably 5 to 50 parts by weight.
In the present invention, the (E) polyorganosiloxane that can be added as necessary is a component for improving the wear resistance, and has a kinematic viscosity of 5000 centistokes (5 × 10 5 at 25 ° C. as defined in JIS-K2410). ⁻³ m ² / sec) or more.
The polyorganosiloxane is in the form of a viscous syrupy to gum, and is not particularly limited as long as it is a polymer containing an alkyl, vinyl and / or aryl group-substituted siloxane unit. Of these, polydimethylsiloxane is most preferred.

The kinematic viscosity (25 ° C.) of the polyorganosiloxane used in the present invention is 5000 CS (5 × 10 ⁻³ m ² / sec) or more, more preferably 10,000 CS (1 × 10 ⁻² m ² / sec). ) 10,000,000 ⁽¹⁰ m 2 / sec) below, and most preferably less than 50,000 CS (0.05m ² / sec) over 2 million ^(2m 2 / sec).
In this invention, it is preferable that the addition amount of polyorganosiloxane is 0.01-20 weight part with respect to a total of 100 weight part of (A) and (B), More preferably, it is 0.1-10. Parts by weight, most preferably 0.5 to 5 parts by weight.
In the present invention, the (E) styrenic elastomer that can be added as necessary is a block copolymer comprising an aromatic vinyl unit and a conjugated diene unit, and more preferably, the conjugated diene unit portion is partially hydrogenated. An added or epoxy-modified block copolymer.

Examples of the aromatic vinyl monomer constituting the block copolymer include styrene, α-methylstyrene, paramethylstyrene, p-chlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, and the like. Yes, styrene is most preferred, but the above aromatic vinyl monomer may be copolymerized mainly with styrene.
Examples of the conjugated diene monomer constituting the block copolymer include 1,3-butadiene and isoprene.
In the block copolymer block structure, a polymer block composed of aromatic vinyl units is represented by S, and a polymer block composed of conjugated dienes and / or partially hydrogenated units thereof is represented by B. SB, S (BS) _n (where n is an integer from 1 to 3), S (BSB) _n (where n is an integer from 1 to 2), (SB) ) _N X (where n is an integer of 3 to 6, X is a coupling agent residue such as silicon tetrachloride, tin tetrachloride, polyepoxy compound, etc.) Star) block copolymers are preferred. Of these, SB type 2, SBS type 3 and SBSB type 4 linear block copolymers are preferred.

The amount of the styrenic elastomer is preferably 1 to 100 parts by weight, more preferably 1 to 50 parts by weight, and most preferably 1 to 30 parts by weight with respect to 100 parts by weight of the total of (A) and (B). Very preferably 1 to 20 parts by weight.
In the present invention, the resin wax (E) that can be added as necessary is a low molecular weight thermoplastic resin, and in the case of an olefin wax, it differs from the (B) in terms of molecular weight.
Regarding the molecular weight of (E), the weight average molecular weight (Mw) calculated by gel permeation chromatography (GPC) is 3000 to 20000, preferably 3000 to 15000, more preferably 5000 to 10,000. Average molecular weight (Mn) is 500-10000, Preferably it is 500-8000, More preferably, it is 1000-5000.

Among the (E) resinous waxes in the present invention, olefinic waxes are preferable, and for example, ethylene and an α-olefin having 3 to 20 carbon atoms are contained. Particularly preferably, the olefin wax produced by a metallocene catalyst comprising a group IV metal cyclopentadienyl derivative such as titanium or zirconium and a co-catalyst has not only a narrow molecular weight distribution but also a copolymer. Has a uniform distribution of α-olefin having 3 to 20 carbon atoms, which is a comonomer, and therefore has less stickiness and bad odor.
In the present invention, if necessary, a thermoplastic resin other than (B) can be contained and is not particularly limited. For example, polyolefin-based, polystyrene-based, polyphenylene ether-based, polyvinyl chloride-based, polyamide-based, polyester A system, a polyphenylene sulfide system, a polycarbonate system, a polymethacrylate system, or the like, or a mixture of two or more types can be used.

In the present invention, other inorganic fillers, plasticizers, organic / inorganic pigments, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, silicone oils, foaming agents to the extent that they do not impair their characteristics It is possible to contain an antistatic agent and an antibacterial agent.
For the production of the composition of the present invention, it is possible to adopt a general method such as a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder or the like used for the production of ordinary resin compositions and elastomer compositions. It is. In particular, a twin screw extruder is preferably used in order to achieve dynamic crosslinking efficiently. In the twin-screw extruder, (A) and (B) are uniformly and finely dispersed, and other components are added to cause a crosslinking reaction, thereby continuously producing the composition of the present invention. Is more suitable.

  As a preferred specific example, the composition of the present invention can be produced through the following processing steps. That is, (A) ((A-1) and (A-2)), (B), and (C) are mixed well and put into a hopper of an extruder. At this time, it is preferable that (A-1) and (A-2) are simultaneously added to the extruder and melt-kneaded. (D) may be added from the beginning together with (A) and (B), or may be added in 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 midway. You may add a part of (A) and (B) from the middle of an extruder. When heated and melted and kneaded in an extruder, the above (A) and (D) undergo a crosslinking reaction, and (E) a softener is added to melt and knead so that the crosslinking reaction and kneading dispersion are sufficient. The pellet of the composition of this invention can be obtained by taking out from an extruder after that.

Further, a particularly preferable melt extrusion method is a case where a twin screw extruder having a length L in the die direction from the raw material addition portion and having an L / D of 5 to 100 (where D is a barrel diameter) is used. is there. The twin-screw extruder has a plurality of supply parts of a main feed part and a side feed part that have different distances from the tip part, and is provided between the supply parts and between the tip part and the tip part. It is preferable that a kneading portion is provided between the supply portion and the supply portion at a short distance from each other, and the length of the kneading portion is 3D to 10D, respectively.
In addition, one twin-screw extruder of the production apparatus used in the present invention may be a twin-screw co-rotating extruder or a bi-shaft counter-rotating extruder. As for the engagement of the screw, there are a non-engagement type, a partial engagement type, and a complete engagement type, and any type may be used. When applying a low shearing force to obtain a uniform resin at a low temperature, a different direction rotation / partial meshing screw is preferred. When slightly larger kneading is required, a co-rotating and complete meshing screw is preferable. When larger kneading is required, a co-rotating and fully meshing screw is preferred.
The most preferable production method of the composition of the present invention is a method in which (A), (B) and (C) are melt-mixed and then crosslinked by (D).

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these. In these examples and comparative examples, the test methods used for evaluating various physical properties are as follows.
1. Melting test As a twin capillary rheometer, using the Advanced Capillary Extension Rheometer manufactured by ROSAND, the shear viscosity (Pa · s) and elongational viscosity (Pa · s) of the molten polymer at a melting temperature of 200 ° C and a shear rate of 10,000 1 / s taking measurement.
2. Continuous productivity As the extruder, a twin-screw extruder (cylinder inner diameter (D) = 40, screw length (L) (L / D) = 50) having an inlet at the center of the barrel is used. As the screw, a double screw having a kneading part before and after the injection port is used.
While the composition is melt extruded at 200 ° C. for 10 hours continuously, pelletization is performed with a strand cutter, and the average number of strand breaks per hour is used as an indicator of continuous productivity.

3. (C) Component fiber formation observation The shape of the component (C) is observed from a transmission electron micrograph photographed by an ultrathin section method of the composition.
4). Molding evaluation A commercially available injection molding machine having a clamping force of 350 tons having a flat plate-shaped mold having a width of 10 cm, a length in the flow direction of 40 cm, and a thickness of 2 mm is used. The cylinder temperature and mold temperature are 200 ° C. and 50 ° C., respectively, the injection pressure and the injection speed are set to 90% and 70% of the capacity of the apparatus, respectively, and the composition is injection molded. The injection moldability is evaluated by evaluating the appearance of the molded body.
◎ Very good.
○ Good △ Good, but the flow mark is slightly conspicuous × Not completely filled or poor appearance such as flow mark is conspicuous In addition, when two symbols are used together like ○ △ etc., in the middle Indicates.

The following are used for each component used in Examples and Comparative Examples.
(A) Crosslinkable rubbery polymer 1) Ethylene / α-olefin copolymer a) Ethylene / propylene / ethylidene norbornene (ENB) copolymer (TPE-1)
It is produced by a method using a metallocene catalyst described in JP-A-3-163088. The composition ratio of ethylene / propylene / ENB of the copolymer is 72/24/4 (weight ratio), and the Mooney viscosity is 100. (Referred to as TPE-1)
b) Ethylene / propylene / ethylidene norbornene (ENB) copolymer (TPE-2) produced by a method using a normal Ziegler catalyst. The composition ratio of ethylene / propylene / ENB of the copolymer is 72/24/4 (weight ratio), and the Mooney viscosity is 105. (Referred to as TPE-2)
c) Copolymer of ethylene and octene-1 (TPE-3)
It was produced by a method using a metallocene catalyst described in JP-A-3-16388. The composition ratio of ethylene / octene-1 in the copolymer is 72/28 (weight ratio), and the Mooney viscosity is 100. (Referred to as TPE-3)

2) Hydrogenated conjugated diene rubber a) Hydrogenated butadiene polymer The hydrogenated butadiene polymer is produced by hydrogenating a butadiene polymer based on the method described in WO01 / 48079. The Mooney viscosity is 100. (Referred to as H-BR)
b) Hydrogenated Styrene / Butadiene Copolymer A styrene / butadiene copolymer is produced by hydrogenation based on the method described in WO01 / 48079. The styrene / butadiene composition ratio of the precursor copolymer is 70/30 (weight ratio), and the Mooney viscosity is 100. (Referred to as H-SBR)

(B) Olefin resin (1) Polypropylene Isotactic homopolypropylene (referred to as PP) MFR: 0.5 g / 10 min (230 ° C., 2.16 kg load)
(C) Extension viscosity improver (1) Branched PP (referred to as b-PP)
Branched homopolypropylene MFR 0.3g / 10min (230 ° C, 2.16kg load)
(2) Acrylic modified polytetrafluoroethylene (referred to as a-PTFE)
Manufactured according to WO 02/090440 A1.

  (3) Polybutylene terephthalate (referred to as PBT)

(D) Crosslinking agent 1) Crosslinking initiator (C-1)
2,5-dimethyl-2,5-bis (t-butylperoxy) hexane (referred to as POX)
2) Polyfunctional monomer (C-2)
Triallyl isocyanurate (referred to as TAIC)
(E) Dispersant 1) Softener Paraffin oil (referred to as MO)
2) Powdery compound Commercially available talc (referred to as TL)

[Examples 1-15 and Comparative Examples 1-2]
As the extruder, a twin screw extruder (cylinder inner diameter (D) = 40, screw length (L) (L / D) = 50) having an inlet at the center of the barrel is used. As the screw, a double screw having a kneading part before and after the injection port is used.
In the composition shown in Table 1, (A), (B), and (C) were first melted at the front stage of the twin-screw extruder, and then (D) and (E) were fed from the side feeder to obtain a cylinder temperature of 160. Melt extrusion is performed under the conditions of ° C., rotation speed of 300 rpm, and discharge rate of 50 kg / hour.
Various evaluations are made on the compositions thus obtained.
The results are shown in Table 1.
According to Table 1, when an elongation viscosity improver is used, the elongation viscosity can be increased without increasing the shear viscosity, so that the strand breakage can be suppressed while maintaining the injection moldability, and the continuous productivity is improved. It turns out that it improves. Moreover, it turns out that the said effect is remarkably high especially when an elongation viscosity improver is fiberized.

  The injection molded article of the present invention is used for automobile parts, automobile interior materials, airbag covers, machine parts, electrical parts, cables, hoses, belts, toys, sundries, daily necessities, building materials, sheets, films, etc. It can be used widely and plays a major role in industry.

Claims (9)

  An injection-molded product of a crosslinked rubber composition comprising a crosslinkable rubbery polymer (A), an olefinic resin (B), and an extensional viscosity improver (C).   The injection molded body of the rubber composition according to claim 1, wherein the component (C) is fiberized.   The injection-molded article according to claim 1 or 2, wherein the component (C) is one or more elongational viscosity improvers selected from a branch-containing olefin resin, a fluorine resin, a polyester resin, and a polyamide resin.   (A) An ethylene / α-olefin copolymer (A-1) produced using a metallocene catalyst, wherein the component contains ethylene and an α-olefin having 3 to 20 carbon atoms, or double in the main chain and side chain One or more crosslinkable rubbers selected from hydrogenated rubbers (A-2) in which 50% or more of all olefinic double bonds of unsaturated rubbers comprising a homopolymer and / or copolymer having a bond are hydrogenated The injection-molded article according to any one of claims 1 to 3, which is a shaped polymer.   (A) component consists of (A-1) component and (A-2) component, and (A-2) component has an aromatic vinyl monomer content of 50 wt% or more and 90 wt% or less. A hydrogenated copolymer obtained by hydrogenating a copolymer comprising a diene monomer and an aromatic vinyl monomer, and wherein the aromatic vinyl monomer portion is mainly bonded randomly. Item 5. An injection-molded article according to Item 4.   The component (B) is a propylene resin, The injection molded article according to any one of claims 1 to 5.   The injection-molded article according to any one of claims 1 to 6, which is crosslinked with a crosslinking agent (C).   The injection molding according to any one of claims 1 to 7, further comprising a softening agent, a powdery compound that does not melt at 250 ° C, a polyorganosiloxane, a styrene thermoplastic elastomer, and a resin wax (D). body.   The skin material according to any one of claims 1 to 8.