JPH09221516A - Thermpolastic olefin elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic olefin elastomer compsn. having a good rubber elasticity and a high heat resistance by cross-linking a mixture comprising an ethylene-α-olefin copolymer rubber, a specific olefin resin, and a butadiene copolymer under specified conditions. SOLUTION: This compsn. is prepd. by dynamically thermally cross-linking. with an org. peroxide, a mixture comprising 40-94 pts.wt. ethylene-α-olefin copolymer rubber formed from ethylene. a 3-20C α-olefin, and if necessary a nonconjugated diene, 5-50 pts.wt. olefin resin comprising an α-olefin (co)polymer having an α-olefin content of 50-100mol% and a melt flow rate of 5-80g/10min, and 1-40 pts.wt. butadiene polymer comprising polybutadiene or an SB rubber. Pref. the ethylene-α-olefin copolymer rubber is an ethylene- propylene-ethylidenenorbornene terpolymer rubber. The mixture is melt kneaded with 0.06-0.4wt.% (based on the mixture) org. peroxide to be cross-linked.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an olefin-based thermoplastic elastomer composition, and more particularly to an olefin-based thermoplastic elastomer composition having no surface roughening and excellent rubber elasticity and heat resistance.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Olefin-based thermoplastic elastomers are excellent in heat resistance, lightweight, and easy to recycle. Therefore, vulcanized rubbers such as NBR, SBR, and BR are used as energy-saving and resource-saving type elastomers. It is widely used as a substitute for automobile parts, industrial machine parts, electric / electronic parts, building materials, etc.

However, the conventional molded article made of an olefinic thermoplastic elastomer has drawbacks in that the elongation at break at break is small and the rubber elasticity is inferior as compared with the molded article made of vulcanized rubber, and its improvement is strong. Is desired.

As a method for improving the rubber elasticity of an olefin-based thermoplastic elastomer, a method of completely crosslinking the olefin-based thermoplastic elastomer while avoiding decomposition of the olefin-based plastic by using a cross-linking agent other than organic peroxide is disclosed in JP-B-58. -46138. However, in such a method, since a phenolic resin and a Lewis acid are used together or sulfur is used as a crosslinking method, the metal portion of the kneading machine is severely corroded and malodorous, and the obtained olefinic thermoplastic elastomer is obtained. The molded article of (1) has a problem that it is colored in a light brown color due to the corrosive metal and the malodorous component and cannot be colored in a vivid color.

When a large amount of organic peroxide is used as a cross-linking agent, the resulting thermoplastic elastomer molded article has improved compression set and oil resistance, but has a problem of rough skin and poor workability. is there.

Therefore, the present inventors provide an olefin-based thermoplastic elastomer molded article which is excellent in rubber elasticity, heat resistance and oil resistance and has a small compression set without causing the above problems. Earnestly researched to obtain a thermoplastic elastomer composition capable of producing a mixture obtained by adding a specific amount of a specific butadiene-based polymer to a specific ethylene / α-olefin copolymer rubber and a specific olefin-based plastic, The present invention has been completed by finding that the target olefin-based thermoplastic elastomer composition can be obtained by dynamically heat-treating and crosslinking in the presence of an organic peroxide.

[0007]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, has no surface roughness, is excellent in rubber elasticity, heat resistance and oil resistance and has a compression set. An object of the present invention is to provide an olefin-based thermoplastic elastomer composition which has a small (CS) and can supply a molded product which can be colored in a bright color.

[0008]

SUMMARY OF THE INVENTION The olefinic thermoplastic elastomer composition according to the present invention comprises [I] ethylene and 3 to 2 carbon atoms.
Ethylene / α-olefin copolymer rubber (a) consisting of 0 α-olefin and, if necessary, non-conjugated diene: 40 to 94 parts by weight, and [II] 3 to 2 carbon atoms.
The content of the α-olefin of 0 is 50 to 100 mol%, and the melt flow rate (ASTM D-123
8-65T, 230 ° C, 2.16kg load) is 5-80
Olefin plastic (b) consisting of α-olefin homopolymer or copolymer in the range of g / 10 minutes:
5 to 50 parts by weight and [III] butadiene homopolymer or styrene-butadiene copolymer rubber butadiene-based polymer (c): 1 to 40 parts by weight [component (a),
The total amount of (b) and (c) is 100 parts by weight] and is a cross-linked product obtained by dynamically heat-treating the mixture in the presence of an organic peroxide.

The above mixture has a total amount of 100 ethylene / α-olefin copolymer rubber (a), olefin plastic (b) and butadiene polymer (c).
It may contain 5 to 50 parts by weight of a non-peroxide type rubber-like substance (d) and / or 5 to 50 parts by weight of a mineral oil-based softening agent (e) with respect to parts by weight.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The olefinic thermoplastic elastomer composition according to the present invention will be specifically described below.

The thermoplastic elastomer composition according to the present invention comprises an ethylene / α-olefin copolymer rubber (a).
An olefin-based plastic (b), a butadiene-based polymer (c), and, if necessary, a peroxide non-crosslinked rubber-like substance (d) and / or a mineral oil-based softening agent (e) in a specific ratio. It is a crosslinked product obtained by dynamically heat treating the contained mixture in the presence of an organic peroxide.

The olefinic thermoplastic elastomer composition according to the present invention has many crosslinking reactions in the competitive reaction between the decomposition reaction and the crosslinking reaction which occur when the rubber component in the above mixture is thermally reacted with the organic peroxide. As a result of many decomposition reactions with components that increase the molecular weight of the polymer inside,
It is a cross-linkable thermoplastic elastomer composition in which a component that reduces the molecular weight of the polymer in the mixture coexists. In this composition, the rubber phase mainly composed of the ethylene / α-olefin-based copolymer rubber (a) and the butadiene-based polymer (c) is highly crosslinked.

Ethylene / α-olefin copolymer rubber
(A) The ethylene / α-olefin copolymer rubber (a) used in the present invention comprises ethylene and α having 3 to 20 carbon atoms.
-Amorphous random elastic copolymer composed of olefin, or amorphous random elastic copolymer composed of ethylene, α-olefin having 3 to 20 carbon atoms and non-conjugated diene, mixed with peroxide However, it is an olefin-based copolymer rubber that is cross-linked to reduce fluidity or does not flow when kneaded under heating.

The ethylene / α-olefin copolymer rubber (a) has an ethylene content of 50 mol% or more, and specific examples thereof include the following rubbers. (1) Ethylene / α-olefin copolymer rubber [ethylene / α-olefin (molar ratio) = about 90/10 to 50 /
50] (2) Ethylene / α-olefin / non-conjugated diene copolymer rubber [ethylene / α-olefin (molar ratio) = about 90
/ 10 to 50/50] Further, specific examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene and ethylidene norbornene. Of these, ethylene / propylene copolymer rubber, ethylene / propylene / non-conjugated diene copolymer rubber, ethylene / 1-butene copolymer rubber, ethylene / 1-butene / non-conjugated diene copolymer rubber are preferable. , Especially ethylene / propylene / non-conjugated diene copolymer rubber, especially ethylene / propylene / ethylidene norbornene copolymer rubber, from which thermoplastic elastomer moldings (non-foam, foam) having an appropriate cross-linking structure can be obtained Is particularly preferable.

The Mooney viscosity [ML _{1 + 4 of the} ethylene / α-olefin copolymer rubber (a) used in the present invention is used.
(100 ° C.)] is preferably in the range of 10 to 250, particularly 30 to 150.

The ethylene value of the ethylene / α-olefin copolymer rubber (a) is preferably 25 or less. When the iodine value of the ethylene / α-olefin-based copolymer rubber (a) is within such a range, a thermoplastic elastomer composition partially cross-linked in good balance can be obtained.

The ethylene / α-olefin copolymer rubber (a) as described above is an ethylene / α-olefin copolymer rubber (a), an olefin plastic (b) and a butadiene polymer (c). It is used in a proportion of 40 to 94 parts by weight, preferably 45 to 85 parts by weight, and more preferably 50 to 80 parts by weight with respect to a total amount of 100 parts by weight.

Olefin-based plastic (b) The olefin-based plastic (b) used in the present invention means a homopolymer or copolymer containing 50 to 100 mol% of α-olefin having 3 to 20 carbon atoms. An olefin-based plastic which is a polymer and which is mixed with peroxide and kneaded under heating to thermally decompose to reduce the molecular weight and increase the fluidity of the resin.

Specific examples of such an olefinic plastic (b) include the following homopolymers or copolymers. (1) Propylene homopolymer (2) Random copolymer of propylene and 10 mol% or less of other α-olefins (3) Block copolymer of propylene and 30 mol% or less of other α-olefins ( 4) 1-Butene homopolymer (5) Random copolymer of 1-butene and other α-olefin at 10 mol% or less (6) 4-Methyl-1-pentene homopolymer (7) 4-Methyl -1-Pentene and other α less than 20 mol%
-Random copolymer with olefin As the α-olefin, specifically, ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-
Hexene, 1-octene and the like. Among the above olefin-based plastics (b), a propylene homopolymer and a propylene / α-olefin copolymer having a propylene content of 50 mol% or more are preferable, and among them, isotactic polypropylene, propylene / ethylene copolymer, Propylene / 1-butene copolymer, propylene / 1-
A hexene copolymer and a propylene-4-methyl-1-pentene copolymer are particularly preferable.

The melt flow rate of this olefinic plastic (b) (ASTM D-1238-65T,
230 ° C, 2.16 kg load) is 5 to 80 g / 10
Min, particularly preferably in the range of 5 to 20 g / 10 min.

In the present invention, the olefinic plastic (b) serves to improve the fluidity and heat resistance of the composition. The olefin-based plastic (b) is 5 parts by weight based on 100 parts by weight of the total amount of the above-mentioned ethylene / α-olefin-based copolymer rubber (a), the olefin-based plastic (b) and the butadiene-based polymer (c). -50 parts by weight, preferably 10-40 parts by weight, more preferably 15-30 parts by weight.
When the olefin-based plastic (b) is used in the above proportion, a thermoplastic elastomer composition having good fluidity, which can provide a molded product (non-foamed product, foamed product) having excellent flexibility, can be obtained.

Butadiene-based polymer (c) The butadiene-based polymer (c) used in the present invention means a radical chain reaction when treated with an organic peroxide at a high temperature, and is based on the number of moles of effective oxygen of the added organic peroxide. A rubber-like or liquid butadiene-based polymer which has many crosslinking points and is capable of co-crosslinking with the ethylene / α-olefin-based copolymer rubber (a).

Specific examples of such a butadiene-based polymer (c) include the following homopolymers or copolymers. (1) Butadiene Homopolymer (Polybutadiene) As the bonding mode of butadiene, there are the following 1,2 bond, cis 1,4 bond, and trans 1,4 bond, but any bonding mode may be used.

[0024]

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(2) Styrene / butadiene random copolymer or block copolymer (SBR) having a styrene content of 50% by weight or less The Mooney viscosity of the butadiene-based polymer (c) of the above (1) and (2) [ML _{1 + 4} (100 ° C.)] is preferably 100 or less, particularly preferably 50 or less. Especially in 1,2-polybutadiene, liquid 1,2-polybutadiene is preferable.

In the present invention, the butadiene-based polymer (c) has the role of increasing the crosslinking efficiency of the rubber phase in the thermoplastic elastomer composition and improving the rubber elasticity. The butadiene-based polymer (c) as described above is an ethylene / α-olefin-based copolymer rubber (a), an olefin-based plastic (b) and a butadiene-based polymer (c).
Is used in an amount of 1 to 40 parts by weight, preferably 5 to 30 parts by weight, and more preferably 5 to 25 parts by weight, based on 100 parts by weight in total. When the butadiene-based polymer (c) is used within the above range, a thermoplastic elastomer composition having high elasticity and capable of forming a molded article having an excellent appearance can be obtained.

Peroxide Non-Crosslinked Rubbery Material (d) The mixture used in the present invention is ethylene / α-
In addition to the olefin copolymer rubber (a), the olefin plastic (b) and the butadiene polymer (c),
It may contain a peroxide non-crosslinked rubbery substance (d).

The non-crosslinking peroxide type rubber-like substance (d) is a hydrocarbon type rubber-like substance which does not crosslink even when mixed with peroxide and kneaded under heating and does not deteriorate in fluidity. Examples thereof include polyisobutylene, butyl rubber (IIR), propylene / ethylene copolymer rubber having a propylene content of 70 mol% or more, and propylene / 1-butene copolymer rubber. Among these, polyisobutylene and butyl rubber are preferable in terms of performance and handling. Especially Mooney viscosity [ML _{1 + 4} (100 ℃)] is 60
The following polyisobutylene and butyl rubber are preferable in terms of improving the fluidity of the composition.

In the present invention, "crosslink" means
In a competitive reaction of decomposition reaction and crosslinking reaction that occurs when a polymer is thermally reacted with peroxide, it is a phenomenon that the apparent molecular weight of the polymer in the composition increases as a result of many crosslinking reactions. The term “” means a reaction phenomenon in which the apparent molecular weight of the polymer decreases as a result of the large number of decomposition reactions.

The above-mentioned peroxide non-crosslinking rubber-like substance (d) is, if necessary, ethylene / α-olefin copolymer rubber (a), olefin plastic (b).
And 5 to 50 parts by weight, preferably 5 to 40 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of the total amount of the butadiene-based polymer (c).

Mineral oil softener (e) The mixture used in the present invention is the above-mentioned ethylene / α-
In addition to the olefin-based copolymer rubber (a), the olefin-based plastic (b), the butadiene-based polymer (c) and the peroxide non-crosslinking rubber-like substance (d), a mineral oil-based softening agent (e) is contained. You may stay.

As such a mineral oil-based softening agent (e), the intermolecular force of the rubber is usually weakened during roll processing of the rubber to facilitate the processing and to help disperse the curb black and white carbon. Alternatively, a high-boiling petroleum fraction used for the purpose of lowering the hardness of the vulcanized rubber and increasing the flexibility may be mentioned. This petroleum fraction is classified into paraffin type, naphthene type, aromatic type and the like.

Specific examples of the mineral oil softener (e) include process oil, paraffin, liquid paraffin, white oil, petrolatum, petroleum sulfonate, petroleum asphalt, gilsonite, mineral rubber, petroleum resin and the like. To be

In the present invention, a mineral oil softener (e)
Is an ethylene / α-olefin copolymer rubber (a),
5 to 50 parts by weight, preferably 5 to 45 parts by weight, more preferably 1 based on 100 parts by weight of the total amount of the olefin-based plastic (b) and the butadiene-based polymer (c).
It is used in a proportion of 0 to 30 parts by weight. When the mineral oil-based softening agent (e) is used in the above proportion, the flow of the thermoplastic elastomer composition can be achieved without deteriorating the physical properties such as heat resistance and tensile properties of the molded product (non-foamed product, foamed product). The sex can be improved sufficiently.

Other Ingredients In the present invention, in addition to the mineral oil-based softening agent (e), other softening agents can be used, if necessary, within a range not impairing the object of the present invention. As the softening agent other than the mineral oil-based softening agent (e) used as necessary in the present invention, the softening agents usually used for rubber are suitable, and specifically, such as coal tar and coal tar pitch. Coal tars; fatty oils such as castor oil, linseed oil, rapeseed oil, soybean oil, and coconut oil; tall oil, beeswax, carnauba wax, lanolin and other waxes; ricinoleic acid, palmitic acid, stearic acid, 12-hydroxyl Fatty acids such as stearic acid, montanic acid, oleic acid, and erucic acid or metal salts thereof; ester-based plasticizers such as dioctyl phthalate, dioctyl adipate, dioctyl sebacate; and other microcrystalline wax, liquid thiochol and the like may be added.

Further, in the above mixture used in the present invention, if necessary, a filler, a conventionally known heat stabilizer, an antiaging agent, a weather stabilizer, an antistatic agent, a metal soap, a lubricant such as wax, and the like, Additives such as pigments, dyes, nucleating agents, flame retardants, antiblocking agents, foaming agents and foaming aids can be added within the range not impairing the object of the present invention.

As the filler used as necessary in the present invention, a filler usually used for rubber is suitable, and specifically, calcium carbonate, calcium silicate, clay, kaolin, talc, silica, silica. Sodium, mica powder, asbestos, barium sulfate, aluminum sulfate, calcium sulfate, magnesium carbonate, molybdenum disulfide,
Examples thereof include glass fiber, glass sphere, shirasu balloon, graphite and alumina.

Further, as the conventionally known heat stabilizer, antiaging agent, and weather resistance stabilizer which are optionally used in the present invention, phenol-based, sulfite-based, phenylalkane-based, phosphite-based, amine-based stabilizers are used. And so on.

Further, as the foaming agent used in the present invention, organic and inorganic pyrolyzable foaming agents; water; solvents such as hydrocarbons and fluorocarbons; nitrogen, carbon dioxide,
There are gases such as propane and butane, but a pyrolytic foaming agent is preferable.

Specific examples of the thermal decomposition type foaming agent include:
Inorganic foaming agents such as sodium hydrogen carbonate, sodium carbonate, ammonium hydrogen carbonate, ammonium carbonate, ammonium nitrite; N, N'-dimethyl-N, N'-dinitrosoterephthalamide, N, N'-dinitrosopentamethylenetetramine, etc. Azo compounds such as azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl) Hydrazide), diphenyl sulfone-3,3'-disulfonyl hydrazide and other sulfonyl hydrazide compounds; calcium azide, 4,4'-diphenyl disulfonyl azide, p-toluene sulfonyl azide and other azide compounds.

These foaming agents are used in an arbitrary ratio according to the desired expansion ratio. Further, if necessary, a foaming aid can be added, and as the foaming aid, zinc,
A metal compound such as calcium, lead, iron or barium; an organic acid such as salicylic acid, phthalic acid or stearic acid, or urea or a derivative thereof is used. The foaming auxiliary agent functions to lower the decomposition temperature of the foaming agent, promote decomposition, uniformize bubbles, and the like.

Olefinic Thermoplastic Elastomer Composition As described above, the olefinic thermoplastic elastomer composition according to the present invention comprises an ethylene / α-olefinic copolymer rubber (a) and an olefinic plastic (b).
And a butadiene-based polymer (c) and, if necessary, a peroxide-non-crosslinked rubber-like substance (d), a mineral oil-based softening agent (e)
It is a crosslinked product obtained by dynamically heat treating a mixture containing and the like in the presence of an organic peroxide.

Specific examples of the above organic peroxide include dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di- (tert-butylperoxy).
Hexane, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy)- 3,3,5-trimethylcyclohexane, n-butyl
-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperbenzoate, tert-butylperoxyisopropyl carbonate, Diacetyl peroxide, lauroyl peroxide, tert-butylcumyl peroxide and the like.

Among these, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane and 2,5-dimethyl-2,5-di-from the viewpoint of odor and stability of scorch. (Tert-Butylperoxy) hexyne-3,1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4 1,4-bis (tert-butylperoxy) valerate is preferred, and among them, 1,3-bis (tert-butylperoxyisopropyl) benzene is most preferred.

The above organic peroxide is ethylene / α-
0.05 to 3% by weight, preferably 0.05 to 1% by weight, based on 100% by weight of the total amount of the olefin-based copolymer rubber (a), the olefin-based plastic (b) and the butadiene-based polymer (c). %, More preferably 0.06-0.
Used in a proportion of 4% by weight.

In the present invention, during the crosslinking treatment with the above organic peroxide, sulfur, p-quinonedioxime, p,
Peroxy crosslinking aids such as p'-dibenzoylquinone dioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene, diphenylguanidine, trimethylolpropane-N, N'-m-phenylenedimaleimide, Or polyfunctional methacrylate monomers such as divinylbenzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, vinyl butyrate, vinyl stearate. Polyfunctional vinyl monomers can be included.

By using the above compound,
A uniform and mild crosslinking reaction can be expected. Particularly, in the present invention, divinylbenzene (DVB) is most preferable. Divinylbenzene is easy to handle and is compatible with the ethylene / α-olefin copolymer rubber (a), the olefin plastic (b) and the butadiene polymer (c) which are the main components of the above-mentioned substance to be crosslinked. Is good, and
Since it has a function of solubilizing the organic peroxide and acts as a dispersant for the organic peroxide, it is possible to obtain a thermoplastic elastomer composition having a uniform cross-linking effect by heat treatment and a good balance of fluidity and physical properties.

In the present invention, the above-mentioned crosslinking aid or polyfunctional vinyl monomer is the above-mentioned ethylene.
0.05-3% by weight, preferably 0.1-3% by weight, based on 100% by weight of the total amount of the α-olefin-based copolymer rubber (a), the olefin-based plastic (b) and the butadiene-based polymer (c). 1% by weight, more preferably 0.1 to 0.
It is preferably used in a proportion of 6% by weight. When the blending ratio of the crosslinking aid or the polyfunctional vinyl monomer is within the above range, the resulting thermoplastic elastomer composition may have the crosslinking aid and the polyfunctional vinyl monomer remaining as unreacted monomers in the elastomer. Since it does not exist, physical properties do not change due to heat history during processing and molding, and it has excellent fluidity.

The above-mentioned "dynamically heat-treating" means kneading the above-mentioned components in a molten state. Dynamic heat treatment is performed using a kneading device such as a mixing roll, an intensive mixer (for example, Banbury mixer, kneader), a single-screw or twin-screw extruder, etc., but in a non-open kneading device such as a Banbury mixer. Is preferred. The dynamic heat treatment is preferably performed in an inert gas such as nitrogen or carbon dioxide.

The kneading is preferably carried out at a temperature at which the half-life of the organic peroxide used is less than 1 minute.
The kneading temperature is usually 150 to 280 ° C., preferably 170
To 240 ° C., and the kneading time is 1 to 20 minutes, preferably 1 to 5 minutes. The shearing force applied at the time of kneading is usually determined within the range of 10 to 10 ⁴ sec ^-1 , preferably 10 ² to 10 ⁴ sec ^-1 in terms of shear rate.

In the present invention, a preferable method for mixing and kneading the above-mentioned respective components is ethylene.
The α-olefin-based copolymer rubber (a), the olefin-based plastic (b) and the butadiene-based polymer (c) were mixed in advance and uniformly kneaded to form pellets, and the obtained pellets and divinylbenzene were added. The dissolved organic peroxide and, if necessary, further a crosslinking aid, a vulcanization accelerator and the like are mixed with a known kneader such as a tumbler type Brabender, a V type Brabender or a Henschel mixer, preferably at 50 ° C. or lower. It is desirable to employ a method of uniformly mixing at temperature and then kneading under the predetermined conditions.

Next, if necessary, the thermoplastic elastomer composition obtained by the above method is blended with a blending agent such as a foaming agent, a foaming aid and a wetting agent. Further, a weather resistance stabilizer, a heat resistance stabilizer, an antioxidant, a colorant and the like may be added at any stage of the above process.

As described above, a thermoplastic elastomer composition in which the rubber phase containing the ethylene / α-olefin copolymer rubber (a) and the butadiene polymer (c) as main components is highly crosslinked is obtained. .

The degree of crosslinking of the olefinic thermoplastic elastomer composition according to the present invention is 85 to 100% by weight, preferably 90 to 100% by weight, particularly preferably 95 to 100% by weight, as a gel content measured by the following method. Is within the range of. [Measurement method of gel content] About 100 mg of a sample of the thermoplastic elastomer composition was weighed and 0.5 mm × 0.5 m
It is cut into m × 0.5 mm strips, and the strips obtained are then placed in 30 ml of cyclohexane in a closed container at 23 ° C.
Soak for 48 hours.

Next, this sample is taken out on a filter paper and dried at room temperature for 72 hours or more until a constant weight is obtained. The value obtained by subtracting the weight of the cyclohexane-insoluble component (fibrous filler, filler, pigment, etc.) other than the polymer component from the weight of this dry residue is defined as "corrected final weight (Y)".

On the other hand, a value obtained by subtracting the weight of the cyclohexane-soluble component (eg, softening agent) other than the polymer component and the weight of the cyclohexane-insoluble component (fibrous filler, filler, pigment, etc.) other than the polymer component from the weight of the sample. Is the “corrected initial weight (X)”.

Here, the gel content (cyclohexane insoluble content) is obtained by the following formula. Gel content [% by weight] = [corrected final weight (Y) / corrected initial weight (X)] × 100 As described above, the olefin-based thermoplastic elastomer composition according to the present invention comprises ethylene / α-olefin. Since the rubber phase mainly composed of the copolymer rubber (a) and the butadiene polymer (c) is highly crosslinked, it has excellent rubber properties such as compression set and impact resilience.

From the olefinic thermoplastic elastomer composition according to the present invention, extrusion molding, press molding, injection molding,
A non-foamed molded product can be prepared by various molding methods such as calender molding.

Further, a foam can be prepared from the olefin-based thermoplastic elastomer composition containing the foaming agent according to the present invention. As the foam molding method, various molding methods such as extrusion molding, press molding, injection molding and calender molding that have been conventionally used for obtaining foam molded articles can be adopted.

As a method for preparing a foam by an extrusion molding method, for example, the above-mentioned composition is melted by an extruder,
There is a method of molding a foam by extruding it from a die and foaming it. The resin temperature during extrusion is preferably in the range of 110 to 250 ° C.

As a method of preparing a foam by a press molding method, for example, pellets of the above-mentioned composition are inserted into a heated mold of a press molding machine, and a mold pressure is applied or a mold pressure is applied. Without this, there is a method of forming a foam by melting the composition and then foaming the composition. The mold temperature is preferably in the range of 110 to 250 ° C.

As a method for preparing a foam by an injection molding method, for example, the composition described above is heated and melted by an injection molding machine, and then injected into a mold so that the tip of a nozzle foams the composition to obtain a foam. There is a method of molding. The resin temperature during injection is preferably in the range of 110 to 250 ° C.

[0063]

EFFECT OF THE INVENTION The olefinic thermoplastic elastomer composition according to the present invention does not use a phenolic resin and a Lewis acid together in the preparation thereof or does not use sulfur. It can be prepared without generating a bad odor. Therefore, the olefinic thermoplastic elastomer composition according to the present invention,
It is possible to provide a molded product that can be colored in a bright color.

Further, the olefinic thermoplastic elastomer composition according to the present invention has a compression-permanent property which does not cause roughening of the extruded surface and has excellent rubber elasticity (large elongation at break at tensile strength), heat resistance and oil resistance. It is possible to provide a molded product having a small strain (CS).

Since the olefinic thermoplastic elastomer composition according to the present invention has the effects as described above, it is used for automobile parts such as glass run channels, weatherstrip sponges, body panels, steering wheels, side shields; shoe soles, sandals, etc. Footwear; electric parts such as wire coating rubber, connectors, cap plugs; civil engineering materials such as water boards, noise barriers; golf club grips, baseball bat grips, swimming fins, leisure glasses such as underwater glasses, gaskets, waterproofing It can be widely used for miscellaneous items such as cloths, garden hoses, and belts.

[0066]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The measurement of the gel content of the thermoplastic elastomer composition in Examples and the like is as described above. Further, the tensile strength at break of the molded body obtained in Examples etc., the elongation at tensile break,
The hardness, compression set, oil resistance and heat resistance tests were carried out by the following methods. [Test method] (1) Tensile test JIS K 63 after punching a thermoplastic elastomer sheet
No. 3 type dumbbell test piece described in No. 01 (1989) was prepared, and this test piece was used for JIS K 630.
According to the method defined in 1 paragraph 3, a tensile test was performed under the conditions of a measurement temperature of 25 ° C. and a tensile speed of 500 mm / min to measure the tensile strength at break (MPa) and the elongation at break (%). (2) Hardness test A hardness test was performed in accordance with JIS K 6301 (1989) to measure spring hardness (JIS A hardness).

(3) Compression set test In accordance with the low temperature compression set test defined in JIS K 6301 (1989), the compression set test was conducted under the following conditions, and the compression set (%) I asked. Test temperature = 70 ° C., test time = 22 hours (4) Oil resistance test The test piece was immersed in JIS No. 3 oil at 70 ° C. in accordance with the dipping test specified in JIS K 6301 (1989).
It was soaked for 70 hours and the volume change rate (%) was measured. (5) Rough skin evaluation Visually observing the appearance of the strands that came out of the extruder at the time of producing the thermoplastic elastomer, and when there is no rough skin, "none" is given,
The one in which rough skin was observed was defined as "present".

[0068]

Example 1 63 mol% ethylene content, 1 iodine value
3. 49 parts by weight of ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (a) (hereinafter abbreviated as EPDM) having a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 75 and a melt flow rate (ASTM D-1238-6
5T, 230 ° C, 2.16kg load) is 20g / 10
Minutes, 30 parts by weight of a propylene homopolymer (b) having a density of 0.91 g / cm ³ (hereinafter abbreviated as PP-1), a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 44, cis 1, Polybutadiene rubber (c) having a 4-bond content of 96% (hereinafter,
21 parts by weight of BR), 10 parts by weight of butyl rubber (d) (hereinafter abbreviated as IIR) having a degree of unsaturation of 0.5% and a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 40, and naphthene. 30 parts by weight of the system process oil (e) (hereinafter abbreviated as oil) in a nitrogen atmosphere with a Banbury mixer, 1
The mixture was kneaded at 80 ° C. for 5 minutes, passed through a sheeting roll, and pellets were manufactured with a sheet cutter.

Next, 140 parts by weight of the pellets obtained as described above and 0.1 part by weight of 1,3-bis (tert-butylperoxyisopropyl) benzene (hereinafter abbreviated as PO) were added to divinylbenzene (hereinafter, Abbreviated as DVB) 0.2
The solution dissolved and dispersed in parts by weight was mixed with a tumbler blender, and this solution was uniformly attached to the pellet surface.

Next, the pellets were extruded at 210 ° C. in a nitrogen atmosphere using an extruder and subjected to dynamic heat treatment (melt kneading) to obtain a thermoplastic elastomer composition having a gel content of 98%. It should be noted that during the melt-kneading, the metal corrosion and the foul odor of the kneader do not occur, and the strand has a good skin condition,
There was no strand break.

The thermoplastic elastomer composition obtained as described above was molded into a shape having a thickness of 1 mm, a length of 200 mm and a width of 200 mm by using a press molding machine under the following conditions.
Test pieces for the above-mentioned tensile test, hardness test, compression set test, oil resistance test and heat resistance test were prepared from the obtained molded body, and these tests were conducted. <Press conditions> Press temperature: 190 ° C. Press time: Preheat 6 minutes, main pressurization 4 minutes, cooling 4 minutes The results are shown in Table 1.

[0072]

Example 2 In Example 1, the EP used in Example 1 was used.
Except that 49 parts by weight of ethylene / propylene copolymer rubber (hereinafter abbreviated as EPM) having an ethylene content of 72 mol% and a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 70 was used in place of DM. The procedure was as in Example 1. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

Table 1 shows the results.

[0074]

Example 3 In Example 1, the PP used in Example 1 was used.
-1 instead of melt flow rate (ASTM D-1
238-65T, 230 ° C, 2.16kg load) is 5
0, except that 30 parts by weight of a propylene homopolymer having a density of 0.91 g / cm ³ (hereinafter abbreviated as PP-2) was used.
Performed in the same manner as in Example 1. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0076]

[Example 4] The BR used in Example 1 in Example 1
Except that 21 parts by weight of a styrene-butadiene copolymer rubber (hereinafter abbreviated as SBR) having a styrene content of 23.5% by weight and a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 52 was used instead of The same procedure as in Example 1 was performed. It should be noted that, during the melt-kneading, metal corrosion of the kneading machine and bad odor did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0078]

Fifth Embodiment In the first embodiment, the EPDM of the first embodiment,
The blending amounts of PP-1 and BR are 85 parts by weight,
The same procedure as in Example 1 was repeated except that the amount was changed to 10 parts by weight and 5 parts by weight. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0080]

Example 6 Example 4 was repeated except that the amounts of EPDM, PP-1 and SBR were changed to 50 parts by weight, 10 parts by weight and 40 parts by weight, respectively. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0082]

Example 7 The procedure of Example 1 was repeated, except that the amounts of EPDM, PP-1 and BR were changed to 50 parts by weight, 45 parts by weight and 5 parts by weight, respectively. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0084]

Example 8 Example 8 was repeated except that the amounts of EPDM, PP-1 and SBR were changed to 40 parts by weight, 35 parts by weight and 25 parts by weight, respectively. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0086]

Example 9 In Example 1, EPDM and PP-
The amount of 1 was changed to 85 parts by weight and 10 parts by weight respectively, and liquid polybutadiene having a 1,2 bond content of 98% or more (hereinafter abbreviated as liquid PB) was replaced by 5 instead of BR.
The same procedure as in Example 1 was carried out except that the parts by weight were used. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0088]

Comparative Example 1 Example 1 was repeated except that the amounts of EPDM, PP-1 and BR were changed to 70 parts by weight, 30 parts by weight and 0 part by weight, respectively. It should be noted that, during the melt-kneading, metal corrosion and a bad odor of the kneader did not occur, the strand had a good skin condition, and the strand did not break.

The results are shown in Table 1.

[0090]

Comparative Example 2 The procedure of Example 1 was repeated except that the amounts of EPDM and BR were changed to 20 parts by weight and 50 parts by weight, respectively, but molding was not possible.

[0091]

Comparative Example 3 In Example 1, EPDM, BR, PO
The same procedure as in Example 1 was repeated, except that the blending amounts of DVB and DVB were changed to 70 parts by weight, 0 parts by weight, 0.5 parts by weight, and 0.7 parts by weight, respectively. It should be noted that, although metal corrosion and a bad odor of the kneader did not occur during the melt kneading, the skin condition of the strand was poor, the strand was frequently broken, and the workability was poor.

The results are shown in Table 1.

[0093]

[Table 1]

Claims (5)

[Claims] 1. [I] Ethylene, α having 3 to 20 carbon atoms
-Ethylene / α-olefin copolymer rubber (a) consisting of olefin and, if necessary, non-conjugated diene: 4
0 to 94 parts by weight, the content of [II] α-olefin having 3 to 20 carbon atoms is 50 to 100 mol%, and
Melt flow rate (ASTM D-1238-65
T, 230 ° C, 2.16 kg load) is 5 to 80 g / 10
Olefin plastics (b) consisting of α-olefin homopolymers or copolymers in the range of minutes: 5 to 50
Parts by weight and [III] butadiene homopolymer or styrene-butadiene copolymer rubber butadiene polymer (c): 1 to 40 parts by weight [total amount of components (a), (b) and (c)] Is 100 parts by weight], which is a crosslinked product obtained by dynamically heat-treating a mixture thereof in the presence of an organic peroxide. 2. The total amount of the mixture of ethylene / α-olefin copolymer rubber (a), olefin plastic (b) and butadiene polymer (c) is 100.
It is a mixture containing 5 to 50 parts by weight of a non-crosslinking rubbery substance (d) and / or 5 to 50 parts by weight of a mineral oil-based softening agent (e) with respect to parts by weight. The olefinic thermoplastic elastomer composition according to claim 1. 3. The ethylene-α-olefin-based copolymer rubber (a), wherein the α-olefin is propylene or 1-butene.
The olefinic thermoplastic elastomer composition described in 1. 4. The non-crosslinked peroxide rubber-like substance (d) is polyisobutylene or butyl rubber (II
R), The olefinic thermoplastic elastomer composition according to claim 2. 5. The olefinic thermoplastic elastomer composition according to claim 1, which is a crosslinked product obtained by dynamically heat treating the mixture in the presence of an organic peroxide and divinylbenzene. .