JP7069760B2 - Modified elastomer composition, crosslinked elastomer composition and molded article thereof - Google Patents

Description

The present invention relates to a modified elastomer composition, a crosslinked elastomer composition and a molded product thereof. More specifically, the present invention relates to a modified elastomer composition and a crosslinked elastomer composition having excellent compression set and durability, and a molded product using the same.

The thermoplastic elastomer means an elastomer that softens by heating and has fluidity, and when cooled, it has rubber elasticity. Thermoplastic elastomers have the same formability as thermoplastic resins, have rubber elasticity, and are recyclable. Therefore, automobile parts, building parts, medical parts, electric wire covering materials, miscellaneous goods, etc. It is widely used in various applications.

It is important to have good rubber elasticity or compression set characteristics when used in applications that require sealing properties, and much research has been done for this purpose, but thermoplastic elastomers ensure thermoplasticity. Therefore, since it contains a thermoplastic resin such as a polyolefin, its compressive permanent strain characteristics are insufficient as compared with thermosetting rubber, and its usable use is limited. On the other hand, thermosetting rubbers such as EPDM have excellent compression set characteristics, but have the disadvantages that they require a long crosslinking step and are inferior in durability.

For example, Patent Documents 1 to 3 propose silane-modified elastomer compositions having improved compression set, but it is necessary to add a large amount of unsaturated silane compound to improve the compression set. There were problems with economics and productivity. Patent Document 4 also proposes an elastomer composition by silane modification, but the compression set is insufficient at a pressure of more than 50% (70 ° C. × 22 hours). Patent Document 5 proposes a dynamically cross-linked thermoplastic elastomer composition using a cross-linking agent such as a phenol resin. However, as described above, since the component contains a non-cross-linked thermoplastic resin, it is compressed and permanently strained. The properties were inadequate.

International Publication No. 2016/140251 International Publication No. 2016/140252 International Publication No. 2016/140253 Japanese Patent No. 5346285 Special Table No. 2005-516098

The present invention has been made in view of the above problems, and an object thereof is a modified elastomer composition which exhibits compression set characteristics similar to those of a conventional thermosetting rubber and has durability similar to that of a thermoplastic elastomer composition. It is an object of the present invention to provide an article, a crosslinked elastomer composition and a molded product thereof.

As a result of diligent studies to solve the above problems, the present inventor has obtained a modified elastomer composition obtained by graft-modifying a composition containing an ethylene / α-olefin copolymer rubber and an unsaturated silane compound, or further. It has been found that a crosslinked elastomer composition obtained by subjecting this to a crosslinking reaction can obtain a molded product having compression permanent strain characteristics equivalent to those of a thermosetting rubber, which was originally considered impossible, and completed the present invention. rice field.
That is, the gist of the present invention lies in the following [1] to [7].

[1] A modified elastomer composition containing the following components (A) to (C) and grafted with the following components (D), wherein the component (B) is 0 with respect to 100 parts by mass of the component (A). A modified elastomer composition having an amount of 0.01 to 5 parts by mass and a component (C) of 0.001 to 2 parts by mass with respect to 100 parts by mass of the component (A).
Component (A): Ethylene / α-olefin copolymer rubber component (B): Saturated silane compound component (C): Crosslinking aid component (D): Peroxide

[2] The modified elastomer composition according to [1], wherein the amount of the component (D) used is 0.01 to 3 parts by mass with respect to 100 parts by mass of the component (A).

[3] The modified elastomer composition according to [1] or [2], wherein the end peak temperature of melting measured by a differential scanning calorimeter (DSC) of the component (A) is 115 ° C. or higher.

[4] The modified elastomer composition according to any one of [1] to [3], wherein the component (B) is a compound represented by the following formula (1).
RSi (R') ₃ ... (1)
(However, R is an ethylenically unsaturated hydrocarbon group, and R'is a hydrocarbon group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms independently of each other, and at least one of R'. One is an alkoxy group having 1 to 10 carbon atoms.)

[5] The modified elastomer composition according to any one of [1] to [4], further comprising component (E): 0.5 to 200 parts by mass of a softening agent.

[6] A crosslinked elastomer composition obtained by subjecting the modified elastomer composition according to any one of [1] to [5] to a crosslinking reaction with a component (F): silanol condensation catalyst.

[7] A molded product molded from the modified elastomer composition according to any one of [1] to [5] or the crosslinked elastomer composition according to [6].

According to the present invention, it is possible to provide a modified elastomer composition and a crosslinked elastomer composition having excellent compression set and good durability, and a molded product using the same.
The modified elastomer composition and the crosslinked elastomer composition of the present invention, and a molded product using the same, are exposed to applications requiring good rubber elasticity, in which thermosetting rubber is conventionally used, and to a harsher usage environment. Expected to be applied to various applications.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following description, and can be arbitrarily modified and carried out without departing from the gist of the present invention. In this specification, when a numerical value or a physical property value is inserted before and after using "-", it is used as including the values before and after that.

[Modified Elastomer Composition]
The modified elastomer composition of the present invention contains the following components (A) to (C) and is grafted with the component (D), and preferably further contains the following component (E).
Component (A): Ethylene / α-olefin copolymer rubber by 100 parts by mass Component (B): Unsaturated silane compound by 0.01 to 5 parts by mass Component (C): Crosslinking aid by 0.001 to 2 parts by mass Part component (D): Peroxide The peroxide is preferably used in an amount of 0.01 to 3 parts by mass with respect to 100 parts by mass of the component (A).
Component (E): 0.5 to 200 parts by mass of softener

[Crosslinked elastomer composition]
The crosslinked elastomer composition of the present invention is obtained by subjecting the modified elastomer composition to a crosslinking reaction with the following component (F).
Component (F): Silanol condensation catalyst

<Mechanism>
The mechanism by which the modified elastomer composition and the crosslinked elastomer composition of the present invention have an excellent compression set and good durability is presumed as follows.
Due to the effects of the components (B), (C), (F), and the components (C), (D), the degree of cross-linking of the component (A) is significantly increased, high rubber elasticity can be obtained, and the residual double is obtained. Good durability can be obtained because there is no bond.

<Component (A): Ethylene / α-olefin copolymer>
The ethylene / α-olefin copolymer of the component (A) contains an ethylene unit and an α-olefin unit, and the content of the ethylene unit is preferably 50% by mass or more with respect to the total amount of the constituent units thereof. Is. The type of the ethylene / α-olefin copolymer of the component (A) is not particularly limited as long as it is such, and a known ethylene / α-olefin copolymer is appropriately used.

Specific examples of the ethylene / α-olefin copolymer include, for example, an ethylene / propylene copolymer, an ethylene / 1-butene copolymer, an ethylene / 4-methyl-1-pentene copolymer, and an ethylene / 1-hexene. Examples thereof include a copolymer of ethylene such as a copolymer and an ethylene / 1-octene copolymer and one or more of α-olefins having 3 to 10 carbon atoms.

The type of catalyst used in producing the ethylene / α-olefin copolymer is not particularly limited, and examples thereof include a Ziegler-Natta catalyst and a metallocene catalyst. Among these, an ethylene / α-olefin copolymer produced by a metallocene catalyst is preferable.

The ethylene / α-olefin copolymer used in the present invention has a melting end peak temperature (hereinafter sometimes referred to as “melting end point”) measured by a differential scanning calorimeter (DSC) of 115 ° C. or higher. Is preferable. When the melting end point of the ethylene / α-olefin copolymer is 115 ° C. or higher, the shape can be maintained by crystals even at a high temperature. From this viewpoint, the melting end point of the ethylene / α-olefin copolymer is preferably 115 ° C. or higher. However, if the melting end point of the ethylene / α-olefin copolymer is excessively high, there is a risk of poor appearance due to unmelted lumps when the temperature of the molding is raised and early crystallization (melt fracture) when the molding is cooled. Therefore, the melting end point of the ethylene / α-olefin copolymer is usually 145 ° C. or lower. The melting end point of the ethylene / α-olefin copolymer is measured by the method described in the section of Examples described later.

The density of the ethylene / α-olefin copolymer of the component (A) used in the present invention (measured by JIS K6922-1, 2: 1997) is preferably 0.850 to 0.910 g / cm ³ . It is more preferably 0.860 to 0.900 g / cm ³ , and even more preferably 0.860 to 0.880 g / cm ³ . When the density is not more than the above upper limit value, it tends to be flexible and excellent in sealing performance. Further, when the density is equal to or higher than the above lower limit value, the shape can be maintained at room temperature and the hysteresis loss is small, so that the settling (compression permanent strain) tends to be excellent.

The content of the ethylene unit of the ethylene / α-olefin copolymer of the component (A) is preferably 50% by mass or more, more preferably 60% by mass or more. When the content of ethylene units is at least the above lower limit, it tends to be easy to obtain an elastomer composition having excellent mechanical strength and rubber elasticity.
The content of each structural unit of the component (A) can be determined by infrared spectroscopy.

The melt flow rate (MFR) of the ethylene / α-olefin copolymer used in the present invention is a melt flow rate (MFR) measured under the conditions of a temperature of 190 ° C. and a load of 21.2 N in accordance with JIS K7210 (1999). It is preferably 0.01 to 30 g / 10 minutes. If the MFR is too large, the compression set becomes large and the sealing property may be deteriorated. Further, if the MFR is too small, the motor load at the time of modified extrusion is large, the resin pressure rises, the productivity deteriorates, and the surface after molding may be roughened. From these viewpoints, the MFR of the ethylene / α-olefin copolymer is more preferably 0.1 g / 10 minutes or more, while more preferably 10 g / 10 minutes or less.

The ethylene / α-olefin copolymer used in the present invention can be obtained as a commercially available product. For example, Dow Chemical's Engage (registered trademark) series, Nippon Polyethylene's kernel (registered trademark) series, Dow Chemical's Infuse (trademark registered) series, Mitsui Chemicals' Toughmer (registered trademark) series, Mitsui Applicable products can be selected and used from the Evolu (trademark registration) series manufactured by Kagaku Co., Ltd.

As the ethylene / α-olefin copolymer of the component (A), only one type can be used alone, or two or more types can be used in any combination and ratio.

<Component (B): unsaturated silane compound>
The unsaturated silane compound of the component (B) used in the present invention is not limited, but the unsaturated silane compound represented by the following formula (1) is preferably used.
RSi (R') ₃ ... (1)

In the above formula (1), R is an ethylenically unsaturated hydrocarbon group, and R'is a hydrocarbon group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms independently of each other, and is of R'. At least one of them is an alkoxy group having 1 to 10 carbon atoms.

In the formula (1), R is preferably an ethylenically unsaturated hydrocarbon group having 2 to 10 carbon atoms, and more preferably an ethylenically unsaturated hydrocarbon group having 2 to 6 carbon atoms. Specific examples thereof include an alkenyl group such as a vinyl group, a propenyl group, a butenyl group and a cyclohexenyl group.

In the formula (1), R'is preferably a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and more preferably a hydrocarbon group having 1 to 4 carbon atoms or 1 to 4 carbon atoms. It is an alkoxy group of. Further, at least one of R'is preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkoxy group having 1 to 4 carbon atoms. The hydrocarbon group having 1 to 10 carbon atoms of R'may be any of an aliphatic group, an alicyclic group, and an aromatic group, but it is preferably an aliphatic group. The alkoxy group having 1 to 10 carbon atoms of R'may be linear, branched or cyclic, but is preferably linear or branched. When R'is a hydrocarbon group, specifically, an alkyl group represented by a methyl group, an ethyl group, an isopropyl group, a t-butyl group, an n-butyl group, an i-butyl group, a cyclohexyl group, or a phenyl group. Examples thereof include an aryl group typified by a group. When R'is an alkoxy group, specific examples thereof include a methoxy group, an ethoxy group, an isopropoxy group and a β-methoxyethoxy group.

When the unsaturated silane compound is represented by the above formula (1), at least one of the three R's is an alkoxy group, but it is preferable that two R's are alkoxy groups, and all R'are It is more preferably an alkoxy group.

As the unsaturated silane compound, vinyltrialkoxysilane typified by vinyltrimethoxysilane, vinyltriethoxysilane, propenyltrimethoxysilane and the like is desirable among those represented by the formula (1). This is because the vinyl group enables the modification of the component (A) to an ethylene / α-olefin copolymer, and the alkoxy group promotes the crosslinking reaction described later. That is, the alkoxy group introduced by graft-modifying the ethylene / α-olefin copolymer with an unsaturated silane compound reacts with water in the presence of a silanol condensation catalyst and hydrolyzes to generate a silanol group to generate silanol. When the groups are dehydrated and condensed, the ethylene / α-olefin copolymers are bonded to each other and a cross-linking reaction occurs. As these unsaturated silane compounds, one type may be used alone, or two or more types may be used in combination.

<Component (C): Crosslinking aid>
Examples of the cross-linking aid for the component (C) include silicon hydride compounds such as metrohydrogensilicon, and peroxide aids such as sulfur, p-quinonedioxime, p-dinitrosobenzene, and 1,3-diphenylguanidine. Agents: Polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane. Polyfunctional (meth) acrylate compounds such as tri (meth) acrylate and allyl (meth) acrylate; having a bismaleimide structure such as N, N'-m-phenylene bismaleimide and N, N'-m-toluylene bismaleimide. Compounds; trimethylolpropane, trimethylolpropane trimethacrylate, tin chloride (SnCl ₂ ) and the like can be mentioned. Among these, polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, and diallyl phthalate, and polyfunctional (meth) acrylate compounds are preferable.

Phenol resin can also be used as another cross-linking aid. Examples of the phenol resin include alkylphenol formaldehyde, alkylphenol norformaldehyde bromide, and the like.

Only one of these cross-linking aids can be used alone, or two or more of them can be used in any combination and ratio.

<Component (D): Peroxide>
Examples of the peroxide of the component (D) include hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters and organic peroxides contained in the ketone peroxide group, and specific examples thereof are as follows. Something is mentioned.

The hydroperoxide group includes cumenhydroperoxide, tertiary butyl hydroperoxide, etc., and the dialkyl peroxide group includes dicumyl peroxide, jittery butyl peroxide, 2,5-dimethyl-2,5-diter. Shari butyl peroxyhexane, 2,5-dimethyl-2,5-diter Shari butyl peroxyhexin-3, di (2-tershari butyl peroxyisopropyl) benzene, etc. are included, and the diacyl peroxide group includes lauryl. Includes peroxide, benzoyl peroxide and the like. The peroxyester group includes tertiary peroxyacetate, tertiary butylperoxybenzoate, tertiary butylperoxyisopropylcarbonate, etc., and the ketone peroxide group includes cyclohexanone peroxide, etc. These organic peroxides. May be used alone or in combination of two or more.

When used in combination with the above-mentioned cross-linking aid of the component (C), a radical generator having a high thermal decomposition temperature is preferable. From this viewpoint, ditertiary butyl peroxide, di (2-terriary butyl peroxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and dicumyl peroxide are preferable.

<Component (E): softener>
The modified elastomer composition of the present invention can contain a softening agent as a component (E) from the viewpoint of increasing flexibility and improving processability, fluidity and oil resistance.

Examples of the component (E) include a softening agent for mineral oil-based rubber, a softening agent for synthetic resin-based rubber, and the like, and among these, softening for mineral oil-based rubber from the viewpoint of compatibility with other components and the like. Agents are preferred.

The softener for mineral oil-based rubber is generally a mixture of aromatic hydrocarbons, naphthenic hydrocarbons and paraffin-based hydrocarbons, and the ratio of carbon of the paraffin-based hydrocarbon to the total carbon atom is 50% by mass. The above are paraffin oils, naphthenic hydrocarbons with a carbon content of 30 to 45% by mass are naphthenic oils, and aromatic hydrocarbons with a carbon content of 35% by mass or more are aromatic oils. It is called. Among these, as the softener, a liquid hydrocarbon-based rubber softener that is liquid at room temperature (23 ± 2 ° C.) is preferable, and a liquid paraffin oil that is liquid at room temperature is more preferable.
By using a softening agent for liquid hydrocarbon rubber as a softening agent, the flexibility and elasticity of the modified elastomer composition of the present invention can be increased, and the processability and fluidity tend to be dramatically improved. ..

The paraffin-based oil is not particularly limited, but has a kinematic viscosity at 40 ° C. of usually 10 cst (centi-stokes) or more, preferably 20 cSt or more, and usually 800 cSt or less, preferably 600 cSt or less. The pour point is usually −40 ° C. or higher, preferably −30 ° C. or higher, and 0 ° C. or lower is preferably used. The pour point is usually −40 ° C. or higher, preferably −30 ° C. or higher, and 0 ° C. or lower is preferably used. Further, a flash point (COC) of usually 200 ° C. or higher, preferably 250 ° C. or higher, and usually 400 ° C. or lower, preferably 350 ° C. or lower is preferably used.

As the softener of the component (E), only one kind may be used alone, or two or more kinds may be used in any combination and ratio.

<Component (F): Silanol condensation catalyst>
By blending the component (F) silanol condensation catalyst with the modified elastomer composition of the present invention, the composition can be crosslinked between molecules, and the silanol group is generated by reacting with water and hydrolyzing. Further, by dehydrating and condensing the silanol groups, the cross-linking reaction proceeds, and the modified elastomers are bonded to each other to produce a cross-linked elastomer composition having excellent heat resistance.

The silanol condensation catalyst of the component (F) that can be used in the present invention comprises a metal organic acid salt, a titanate, a borate salt, an organic amine, an ammonium salt, a phosphonium salt, an inorganic acid and an organic acid, and an inorganic acid ester. Examples include one or more compounds selected from the group.

Examples of the metal organic acid salt include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, stannous acetate, stannous octanate, cobalt naphthenate, lead octylate, lead naphthenate, and octylic acid. Examples thereof include zinc, zinc caprylate, iron 2-ethylhexanoate, iron octylate, iron stearate and the like. Examples of the titanate include titanate tetrabutyl ester, titanium acid tetranonyl ester, bis (acetylacetonitrile) di-isopropyl titanate and the like. Examples of the organic amine include ethylamine, dibutylamine, hexylamine, triethanolamine, dimethylsoyaamine, tetramethylguanidine, pyridine and the like. Examples of the ammonium salt include ammonium carbonate, tetramethylammonium hydroxide and the like. Examples of the phosphonium salt include tetramethylphosphonium hydroxide. Examples of the inorganic acid and the organic acid include sulfonic acids such as sulfuric acid, hydrochloric acid, acetic acid, stearic acid, maleic acid, toluenesulfonic acid and alkylnaphthylsulfonic acid. Examples of the inorganic acid ester include a phosphoric acid ester and the like.

Among these, metal organic acid salts, sulfonic acids, and phosphate esters are preferable, and more preferably, metal carboxylates of tin, such as dioctyltin dilaurate, alkylnaphthylsulfonic acid, and ethylhexyl phosphate esters, can be mentioned.

The silanol condensation catalysts listed above may be used alone or in combination of two or more.

The silanol condensation catalyst is preferably used as a masterbatch in which a polyolefin and a silanol condensation catalyst are mixed. Examples of the polyolefin that can be used in this masterbatch include polyethylene, polypropylene, and an ethylene / α-olefin copolymer.

Examples of polyethylene include (branched or linear) ethylene homopolymers such as low / medium / high density polyethylene; ethylene / propylene copolymer, ethylene / 1-butene copolymer, and ethylene / 4-methyl-. Ethylene / α-olefin copolymers such as 1-pentene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer; ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid Examples thereof include an ethylene-based copolymer resin such as a copolymer and an ethylene / (meth) acrylic acid ester copolymer. Among these, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 4-methyl-1-pentene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, etc. Ethylene / α-olefin copolymer of the above is preferable.

Among these, in the present invention, high-pressure low-density polyethylene, high-density polyethylene, and an ethylene / α-olefin copolymer having an excellent balance between heat resistance and strength are preferable. The ethylene / α-olefin copolymer is more preferably an ethylene / 1-butene copolymer, an ethylene / 4-methyl-1-pentene copolymer, an ethylene / 1-hexene copolymer, or an ethylene / 1-octene. It is an ethylene / α-olefin copolymer such as a copolymer, and this ethylene / α-olefin copolymer is 1 type or 2 or more types of α-olefin 2 to 60% by mass and ethylene 40 to 98% by mass. It is more preferable that it is a copolymer of and. In the masterbatch of the silanol condensation catalyst, only one of these polyolefins may be used, or two or more of these polyolefins may be blended and used.

When the silanol condensation catalyst is used as a master batch in which a polyolefin and a silanol condensation catalyst are mixed, the content of the silanol condensation catalyst in the master batch is not particularly limited, but is usually about 0.1 to 5.0% by mass. It is preferable to do so.

Commercially available products can be used as the silanol condensation catalyst-containing masterbatch, and for example, "LZ082" and "LZ033" manufactured by Mitsubishi Chemical Corporation can be used.

<Mixing ratio>
In the modified elastomer composition of the present invention, the content of the component (B) with respect to 100 parts by mass of the component (A) is 0.01 to 5 parts by mass, preferably 0, from the viewpoint of sufficiently advancing the crosslinking reaction. It is 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass.
The content of the component (C) is 0.001 to 2 parts by mass with respect to 100 parts by mass of the component (A), and is preferably 0.003 to 1 part by mass from the viewpoint of obtaining economic efficiency and a sufficient cross-linking reaction. Is.
The content of the component (D) is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the component (A), and is more preferable from the viewpoint of obtaining a sufficient cross-linking reaction and maintaining a smooth molded appearance. It is 0.05 to 2 parts by mass, more preferably 0.1 to 1 part by mass.

When the modified elastomer composition of the present invention contains the component (E), the content of the component (E) with respect to 100 parts by mass of the component (A) is 0.5 to 200 parts by mass. If the content of the component (E) is less than the above lower limit, the effect of improving the flexibility, fluidity, and oil resistance of the component (E) cannot be sufficiently obtained, and if the content exceeds the above upper limit, there is a risk of bleeding out from the surface. be. From this viewpoint, the content of the component (E) with respect to 100 parts by mass of the component (A) is preferably 1 to 100 parts by mass, and more preferably 5 to 80 parts by mass.

When the silanol condensation catalyst of the component (F) is added to the modified elastomer composition of the present invention and subjected to a crosslinking reaction, the addition amount thereof is not particularly limited, but the modified elastomer of the present invention excluding the component (F) is not particularly limited. It is preferably 0.001 to 0.5 parts by mass, and more preferably 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the composition. When the addition amount of the silanol condensation catalyst is at least the above lower limit value, the crosslinking reaction proceeds sufficiently and the heat resistance tends to be good, which is preferable. When it is at least the above upper limit value, early crosslinking is unlikely to occur in the extruder. , It is preferable because the strand surface and the appearance of the product tend to be less likely to be roughened.

<Other ingredients>
In addition to the above components, the modified elastomer composition of the present invention contains various additives and fillers, resins and elastomers other than the component (A) as other components within a range that does not impair the effects of the present invention. be able to.

Examples of the additive include a heat stabilizer, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a crystal nucleating agent, a rust inhibitor, a viscosity modifier, a foaming agent, a lubricant, a pigment and the like. can. Of these, it is preferable to contain an antioxidant, particularly a phenolic antioxidant, a sulfur-based antioxidant or a phosphorus-based antioxidant. The antioxidant is preferably contained in 100% by mass of the modified elastomer composition of the present invention in an amount of 0.1 to 1% by mass.

Examples of other resins include polyolefin resins, polyester resins, polycarbonate resins, polymethylmethacrylate resins, rosin and its derivatives, terpene resins and petroleum resins and their derivatives, alkyd resins, alkylphenol resins, terpenephenol resins, and kumaron. Inden resin, synthetic terpene resin, alkylene resin, olefin-based elastomer other than component (A), polyamide-based elastomer such as polyamide / polyol copolymer; polyvinyl chloride-based elastomer, polybutadiene-based elastomer, styrene-based elastomer, hydrogenation thereof Examples thereof include those obtained by modifying with an acid anhydride or the like to introduce a polar functional group, and those obtained by grafting, random and / or block copolymerizing another monomer.

<Manufacturing and molding of modified elastomer composition>
The modified elastomer composition of the present invention comprises known ethylene / α-olefin copolymer rubber, unsaturated silane compounds, peroxides, cross-linking aids, and if necessary, softeners and other components. It can be produced by mechanically mixing with a method, for example, a henschel mixer, a V-blender, a tumbler blender, or the like, and then mechanically melt-kneading by a known method. For this melt-kneading, a general melt-kneader such as a Banbury mixer, various kneaders, a single-screw or twin-screw extruder can be used. Further, as shown in Examples described later, when the composition of the present invention is kneaded and produced by a single-screw or twin-screw extruder or the like, it is usually heated to 120 to 240 ° C, preferably 120 to 220 ° C. Can be melt-kneaded with.

In the modified elastomer composition of the present invention, the above-mentioned silanol condensation catalyst is blended, molded by various molding methods such as extrusion molding, injection molding, and press molding, and then exposed to an aqueous atmosphere to carry out a crosslinking reaction between silanol groups. Can be advanced to obtain a crosslinked elastomer composition. Various conditions can be adopted as the method of exposing to the water atmosphere, the method of leaving in the air containing water, the method of blowing air containing water vapor, the method of immersing in a water bath, and the method of sprinkling hot water in a mist form. How to do it, etc.

In this case, the hydrolyzable alkoxy group derived from the unsaturated silane compound used for the graft modification of the component (A) reacts with water in the presence of a silanol condensation catalyst to hydrolyze to generate a silanol group, and further. By dehydrating and condensing the silanol groups, the cross-linking reaction proceeds, and the modified elastomers are bonded to each other to form a cross-linked elastomer composition.

The progress rate of the cross-linking reaction is determined by the conditions of exposure to the water atmosphere, but usually the exposure may be in the temperature range of 0 to 130 ° C. and in the range of 5 minutes to 1 week. Particularly preferred conditions are a temperature range of 40 to 90 ° C. and a range of 30 minutes to 24 hours. When using moist air, the relative humidity is selected from the range of 1-100%.

The degree of cross-linking of the cross-linked elastomer composition thus obtained can be adjusted by changing the type and blending amount of the silanol condensation catalyst, the conditions (temperature, time) for cross-linking, and the like.

<Use>
The use of the modified elastomer composition and the crosslinked elastomer composition of the present invention is not particularly limited, but for automobile parts such as glass run channels, weather strips, hoses, wiper blades and glomets, packings, gaskets, cushions, anti-vibration rubbers, tubes and the like. It can be suitably used as a building, industrial parts, other sports, miscellaneous goods, medical parts, food parts, household appliances parts, and wire covering materials.

Hereinafter, specific embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. The values of various production conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the above-mentioned upper limit or lower limit value. , The range specified by the combination of the values of the following examples or the values of the examples may be used.

In the following Examples and Comparative Examples, the raw materials used for preparing the elastomer composition and the evaluation method of the obtained elastomer composition are as follows.

[raw materials]
The raw materials used in the following Examples / Comparative Examples are as follows.

<Ethylene / α-olefin copolymer>
(A-1): Engage (registered trademark) XLT8677 (manufactured by Dow Chemical Co., Ltd.)
Ethylene / α-olefin copolymer α-olefin: 1-octene MFR: 0.5 g / 10 minutes (190 ° C, 21.2 N load)
Density: 0.87 g / cm ³
Melting end point: 123 ° C
(A-2): Engage (registered trademark) 8180 (manufactured by Dow Chemical Co., Ltd.)
Ethylene / α-olefin copolymer α-olefin: octene MFR: 0.5 g / 10 minutes (190 ° C, 21.2 N load)
Density: 0.88 g / cm ³
Melting end point: 70 ° C
(A-3): Toughmer (registered trademark) A0550S (manufactured by Mitsui Chemicals, Inc.)
Ethylene / α-olefin copolymer α-olefin: butene MFR: 0.5 g / 10 minutes (190 ° C, 21.2 N load)
Density: 0.86 g / cm ³
End point of melting: 58 ° C
(Note that the method for measuring the melting end points of the components (A-1), (A-2), and (A-3) is as described below.)

<Unsaturated silane compound>
(B) Vinyltrimethoxysilane: KBM-1003 (manufactured by Shin-Etsu Chemical Co., Ltd.)

<Crosslinking aid>
(C-1) Divinylbenzene (mixture of 55% by mass of divinylbenzene manufactured by Wako Pure Chemical Industries, Ltd. and 45% by mass of ethylvinylbenzene)
(C-2) Trimethylolpropane Tremethacrylate (manufactured by Wako Pure Chemical Industries, Ltd.)
(C-3) Bismaleimide (manufactured by Wako Pure Chemical Industries, Ltd.)
(C-4) Triallyl cyanurate (manufactured by Wako Pure Chemical Industries, Ltd.)

<Organic peroxide>
(D-1) Di (2-tertiary butyl peroxyisopropyl) benzene: Perbutyl P (manufactured by NOF CORPORATION)
(D-2) Jitterly Butyl Peroxide: Perbutyl D (manufactured by NOF CORPORATION)
(D-3) 2,5-dimethyl-2,5-di (t-butylperoxy) hexane: Kayahexa AD40C (manufactured by Kayaku Akzo Corporation 2,5-dimethyl-2,5-di (t-butylperoxy) Oxy) Mixture of 40% by mass of hexane and 60% by mass of organic filler)

<Softener>
(E) Paraffin-based rubber softener (paraffin-based oil manufactured by Idemitsu Kosan Co., Ltd. Trade name: Diana (registered trademark) Process oil PW90)
Viscosity at 40 ° C: 95.54 cSt (Centistokes)
Pour point: -15 ° C
Flash point: 272 ° C

<Catalyst Masterbatch (MB)>
(F) Silanol condensation catalyst MB: LZ033 (manufactured by Mitsubishi Chemical Corporation, 1.2% tin catalyst (dioctyl tin dilaurate) -containing linear low-density polyethylene, MFR of low-density polyethylene: 2 g / 10 minutes (190 ° C., 21. 2N load), density of low density polyethylene: 0.92g / cm ³ )

<Other ingredients>
(G-1) Partially crosslinked olefin-based thermoplastic elastomer: 3655B (manufactured by Mitsubishi Chemical Corporation)
(G-2) Completely cross-linked olefin-based thermoplastic elastomer: A64BU (manufactured by Mitsubishi Chemical Corporation)

[Measurement of melting end point of ethylene / α-olefin copolymer]
Using a differential scanning calorimeter manufactured by Hitachi High-Tech Science Co., Ltd., trade name "DSC6220", heat the sample of about 5 mg from 20 ° C to 200 ° C at a heating rate of 100 ° C / min according to JIS K7121. After holding at 200 ° C for 3 minutes, the temperature was lowered to -10 ° C at a cooling rate of 10 ° C / min, and then the temperature was raised to 200 ° C at a heating rate of 10 ° C / min. (° C.) was calculated and used as the melting end point.

[Evaluation methods]
Various evaluation methods of the elastomer composition in Examples and Comparative Examples are shown below.

(1) Surface hardness The obtained molded sheet was measured for Duro A hardness (after 15 seconds) in accordance with JIS K6253 (Duro-A).

(2) Permanent compression strain The obtained molded sheet was measured at 70 ° C. for 22 hours under 25% compression conditions in accordance with JIS K6262 standards.

(3) Evaluation of stickiness immediately after molding The obtained molded sheet was visually evaluated for stickiness before the crosslinking treatment. Those with stickiness were marked with x, and those without stickiness were marked with ○.

[Example 1]
With the raw material blending shown in Table 1, each raw material other than the ingredient (E) was blended and mixed with a Henschel mixer for 1 minute. Next, the obtained mixture is charged into the upstream supply port of the same-direction twin-screw extruder (manufactured by Japan Steel Works, Ltd., product number: TEX30, L / D = 46, number of cylinder blocks: 12) by a mass feeder. bottom. Then, the component (E) is supplied from the supply port in the middle of the extruder by the liquid addition pump, and the temperature is raised in the range of 120 to 200 ° C. from the upstream portion to the downstream portion with a total discharge amount of 25 kg / h. Melt-kneading was performed and pelletized to produce a modified elastomer composition. To 100 parts by mass of the obtained modified elastomer composition, 4 parts by mass (0.048 parts by mass) of LZ033 as the component (F) silanol condensation catalyst MB was added to obtain a modified elastomer composition containing the catalyst MB. Obtained. Using an in-line screw type injection molding machine (manufactured by Toshiba Machine Co., Ltd., product number: IS130), the composition was injection molded under the conditions of an injection pressure of 50 MPa, a cylinder temperature of 220 ° C, and a mold temperature of 40 ° C. A sheet having a thickness of 2 mm, a width of 120 mm, and a length of 80 mm was formed. Further, it was exposed to a constant temperature and humidity chamber at 85 ° C. and 85% RH for 24 hours to prepare a sheet for evaluating surface hardness and compression set.

[Examples 2 to 6 and Comparative Examples 1 to 4]
Treatment was carried out in the same manner as in Example 1 except that the composition was changed to the raw material composition shown in Table 1, to obtain pellets of the modified elastomer compositions of Examples 2 to 6 and Comparative Examples 1 to 4, respectively, and similarly to the evaluation sheet. Molding and evaluation were performed. The evaluation results are shown in Table 1.

In Table 1, the component (C-1) is not the actual compounding amount, but the compounding amount of divinylbenzene alone (actual compounding amount 55%) among the components (C-1), and the component (D) is shown. Regarding -3), not the actual compounding amount, but the compounding amount of only 2,5-dimethyl-2,5-di (t-butylperoxy) hexane among the components (D-3) (the actual compounding amount). 40%).

[Evaluation results]
As shown in Table 1, it can be seen that all of Examples 1 to 6 corresponding to the elastomer composition of the present invention are not sticky and have good compression set.
On the other hand, the elastomer compositions of Comparative Examples 1 to 4 were not sticky or had insufficient compression set.
From these results, it was found that the elastomer composition of the present invention is not sticky and has good sealing properties.

Since the elastomer composition of the present invention is excellent in compression set, it is required to be used in various applications such as automobile parts such as glass run channels and weather strips, civil engineering / building material parts such as building gaskets, sporting goods, industrial parts, and home appliances. It can be widely and effectively used in parts, medical parts, food parts, medical equipment parts, electric wires, miscellaneous goods, and the like.

Claims (6)

A modified elastomer composition containing the following components (A) to (C) and grafted with the following components (D), wherein the component (B) is 0.01 to 100 parts by mass of the component (A). It is 5 parts by mass, and the component (C) is 0.001 to 2 parts by mass with respect to 100 parts by mass of the component (A).
A modified elastomer composition having a melting end peak temperature of 115 ° C. or higher as measured by a differential scanning calorimetry (DSC) for component (A).
Component (A): Ethylene / α-olefin copolymer rubber component (B): Saturated silane compound component (C): Crosslinking aid component (D): Peroxide The modified elastomer composition according to claim 1, wherein the amount of the component (D) used is 0.01 to 3 parts by mass with respect to 100 parts by mass of the component (A). The modified elastomer composition according to claim 1 or 2, wherein the component (B) is a compound represented by the following formula (1).
RSi (R') ₃ ... (1)
(However, R is an ethylenically unsaturated hydrocarbon group, and R'is a hydrocarbon group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms independently of each other, and at least one of R'. One is an alkoxy group having 1 to 10 carbon atoms.) The modified elastomer composition according to any one of claims 1 to 3, further comprising a component (E): 0.5 to 200 parts by mass of a softening agent. A crosslinked elastomer composition obtained by subjecting the modified elastomer composition according to any one of claims 1 to 4 to a crosslinking reaction with a component (F): silanol condensation catalyst. A molded product molded from the modified elastomer composition according to any one of claims 1 to 4 or the crosslinked elastomer composition according to claim 5 .