JPH0517640A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in hardness, moldability, etc., by crosslinking a mixture comprising a plurality of specified polymers, an olefinic copolymer rubber and a mineral oil softener in a specified ratio by dynamic heat treatment in the presence of a crosslinking agent. CONSTITUTION:A mixture comprising 10-70wt.% mixture of a crystalline propylene polymer with at least 20wt.% random copolymer prepared from a 3-12 Calpha-olefin, nonconjugated dienes of formula I (wherein R<1> is 1-8C alkyl; R<2> and R<3> are each H or R<1> and not all of them are H at the same time; and (n) is 2-10) and/or formula II (wherein R<4> is H or CH3; R5 is 1-6C hydrocarbon group; and (m) is 0-1) and ethylene as an optional component and having a content of the nonconjugated dienes of 0.1-15mol%, a crystallinity of 20% or above as determined byX-ray diffraction and a melt flow rate of 0.01-200g/10min and a modulus of 1000-30000kg/cm<2> as determined by a specified standard, 15-50wt.% olefinic copolymer rubber and 15-45wt.% mineral oil softener is crosslinked by dynamic heat treatment in the presence of a crosslinking agent.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION This invention relates to thermoplastic elastomer compositions. More specifically, the present invention relates to a thermoplastic elastomer composition that is used for automobile parts and industrial machine parts, has excellent properties such as flexibility, mechanical strength, and compression set and can substitute for vulcanized rubber.

[0002]

2. Description of the Related Art Thermoplastic elastomers are widely used for automobile parts and industrial machine parts as a substitute for conventional rubber because they do not require a vulcanization step and can be easily recycled and molded.

As one of such thermoplastic elastomers, a propylene polymer, an olefin copolymer rubber, and a thermoplastic elastomer composition containing a mineral oil softener are known. Since it is generally inferior to conventional rubbers in terms of moldability and level and balance of compression set, its use is limited. In order to improve these problems, various attempts have been made to improve the degree of vulcanization, improve the method of adding a mineral oil-based softening agent, and vulcanize with a phenol resin (for example, JP-A-52-13541). JP-A-5
8-46138, JP-A-1-103639, JP-A-2-235949, etc.).

[0004]

However, in the conventional thermoplastic elastomer composition, in order to maintain excellent physical properties such as hardness, mechanical strength, moldability and compression set, which are required as important physical properties, and to maintain the balance. There is still room for improvement.

[0005]

[Summary of the Invention] <Summary> The present invention has been made in view of the above-mentioned problems, and is further improved by conventional techniques to improve the quality of automobile parts, industrial It is an object of the present invention to provide a thermoplastic elastomer composition which is excellent in hardness, moldability, mechanical strength, and compression set required in the field of mechanical parts and the like, and which retains physical properties and maintains balance.

The present inventors have investigated various compounding materials for the thermoplastic elastomer composition, and as a result,
Thermoplastic elastomer obtained by dynamically heat-treating a composition in which a specific olefin copolymer rubber and a mineral oil softener are mixed with a propylene polymer mixture containing a specific random copolymer to crosslink The composition is
The present invention has been completed by finding that it is excellent in hardness, moldability, mechanical strength and compression set.

That is, the thermoplastic elastomer composition according to the present invention comprises the following components (a), (b) and component (c):
It is characterized by being dynamically heat-treated in the presence of a cross-linking agent to cross-link it.

Component (a) at least one α-olefin having 3 to 12 carbon atoms;
At least 1 selected from the following formula (1) and formula (2)
A random copolymer of certain non-conjugated dienes and optionally ethylene, wherein the content of non-conjugated dienes in the copolymer is 0.1 to 15 mol% and crystallized by X-ray diffractometry 20% or more, melt flow rate 0.01 to 200
g / 10 minutes, and elastic modulus according to JIS K7203 is 1
Mixture with a crystalline propylene polymer containing at least 20% by weight of a random copolymer of 000 to 30,000 kg / cm ² 10 to 70% by weight

[0009]

[Chemical 3] (In the formula, R ¹ represents an alkyl group having 1 to 8 carbon atoms, R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, provided that R ² and R ³ are both hydrogen. It is not an atom, and n represents a number of 2 to 10.)

[0010]

[Chemical 4] (In the formula, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrocarbon group having 1 to 6 carbon atoms, and m represents a number of 0 or 1.) Component (b) Olefin-based copolymer rubber 15 -50% by weight Component (c) Mineral oil-based softener 15-45% by weight

<Effect> The thermoplastic elastomer composition according to the present invention has an excellent physical property level and balance in hardness, moldability, mechanical strength and compression set.

[Detailed Description of the Invention] (1) Constituents <Component (a)> [General Description] The random copolymer used in the resin composition of the present invention is an α-olefin having 3 to 12 carbon atoms. Of at least one non-conjugated diene selected from the following formulas (1) and (2), and optionally ethylene, using a known Ziegler catalyst to obtain an α-olefin polymer It can be produced by random copolymerization using a known method / device similar to the production.

[0013]

[Chemical 5] (In the formula, R ¹ represents an alkyl group having 1 to 8 carbon atoms, R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, provided that R ² and R ³ are both hydrogen. It is not an atom, and n represents a number of 2 to 10.)

[0014]

[Chemical 6] (In the formula, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrocarbon group having 1 to 6 carbon atoms, and m represents a number of 0 or 1.)

Α-C3 to C12 used in the present invention
Examples of the olefin include propylene, butene-1, pentene-1, hexene-1, octene-1,3-methyl-butene-1,3-methyl-pentene-1,4-methyl-pentene-1,3,3- Dimethyl-butene-1,4,4-
Dimethyl-pentene-1,3-methylhexene-1,4
-Methyl-hexene-1,4,4-dimethyl-hexene-1,5-methyl-hexene-1, allylcyclopentane, allylcyclohexane, styrene, allylbenzene, 3-cyclohexylbutene-1, vinylcyclopropane, vinylcyclo Pentane, vinylcyclohexane,
2-vinylbicyclo [2.2.1] -heptane and the like can be mentioned. Of these, preferred are propylene, butene-1,3-methyl-butene-1,4-methyl-pentene-1, styrene and the like, and among these, particularly preferred is propylene. Two or more of these α-olefins may be used, in which case one of the main α-olefins is α-olefin.
It is 70% by weight or more, preferably 80% by weight or more, particularly preferably 90% by weight or more, based on the total amount of olefins.

The above general formula (1) used in the present invention
Examples of non-conjugated dienes represented by
5-dienes such as 1,5-heptadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 1,5-octadiene, 5-methyl-1,5
(B) 1,6-dienes such as -octadiene and 6-methyl-1,5-octadiene, for example 1,6-octadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene , 7-ethyl-1,6-octadiene, 1,6-nonadiene, 7-methyl-1,6-nonadiene, 4-methyl-1,6-nonadiene, etc.,
(C) 1,7-dienes such as 1,7-nonadiene,
(D) Other dienes such as 8-methyl-1,7-nonadiene, eg 1,11-dodecadien, 1,13-
Examples include various non-conjugated dienes such as tetradecadiene. Among these, 6-methyl-1,5
-Heptadiene, 6-methyl-1,5-octadiene,
6-methyl-1,6-octadiene, 7-methyl-1,
Branched non-conjugated dienes such as 6-octadiene, 7-ethyl-1,6-octadiene, and 8-methyl-1,7-nonadiene are preferable from the viewpoint of copolymer production technology, and especially 7-
Methyl-1,6-octadiene is preferred.

The dialkenylbenzene represented by the above formula (2) may be any of isomers such as o-form, m-form and p-form, and may be a mixture of these isomers. Further, various derivatives in which the benzene ring is substituted with the group R ⁵ may be used. Specific examples are divinylbenzene, isopropenylstyrene, divinyltoluene and the like.

Of course, these non-conjugated dienes may be a mixture of two or more kinds. The propylene copolymer containing the diene unit represented by the formula (1) and / or the formula (2) can be produced by any known method, for example, JP-A-1-
The method described in each of Japanese Patent No. 118510 or No. 56-30414 can be used.

The random copolymer used in the present invention is
The content of the non-conjugated dienes is 0.1 to 15 mol%, preferably 0.2 to 12 mol%, particularly preferably 0.5 to 8 mol%. If the content of the non-conjugated diene is less than 0.1 mol%, the content of the unsaturated group in the random copolymer resin is small, so that the effect of crosslinking cannot be fully enjoyed. Excessive amounts are not preferable because the productivity of resin production is poor and a non-uniform crosslinking reaction may occur.

The random copolymer used in the present invention is
If necessary, it contains ethylene as a copolymerized unit. The ethylene unit is optionally introduced for the purpose of adjusting or improving physical properties required for the random copolymer, such as transparency, flexibility and melting point, depending on the use of the random copolymer. .. Therefore, the content of ethylene units is appropriately determined depending on the use of the copolymer and other circumstances. Usually, the content of ethylene units is 0 to 4 mol%, preferably 0 to 3.5 mol%, particularly preferably 0.
.About.2 mol%. When the content of ethylene units becomes large, the crystallinity of the target random copolymer is lowered too much,
There is a problem that the properties of the random copolymer as a resin deteriorate.

The random copolymer used in the present invention has a crystallinity of X-ray diffraction method (for example, G. Natta et al., Rend. Accad. Naz. Lince for propylene polymer resin).
i. 22 (8), 11 (1957) method), measured value is 20% or more. In the case of a propylene-based random copolymer, 25% or more is particularly desirable.

Further, the random copolymer used in the present invention has a melt flow rate of 0.01 to 200 g / 10.
Min, particularly preferably 0.1 to 100 g / 10 min.

The random copolymer used in the present invention has a melting point of 10 at the melting peak temperature by DSC.
0 to 330 ° C., preferably 110 ° C. to 300 ° C., and particularly preferably 120 in the case of a propylene random copolymer.
Those existing in the range of ℃ to 160 ℃ are general.
If the melting point is less than 100 ° C, the heat resistance of the α-olefin resin cannot be exhibited, which is not preferable.

Further, the random copolymer used in the present invention has a property as a resin,
Flexural modulus according to K7203 is 1000-30,000
kg / cm ² , preferably 1000-25,000 kg / c
m ² , particularly preferably 1500-10,000 kg / c
It exists in the range of m ² . 1000 kg / cm ²
If it is less than the above range, the properties of the resin are deteriorated and the mechanical strength and oil resistance of the thermoplastic elastomer composition are deteriorated, which is a problem.

Component (a) of such a random copolymer
The proportion therein is at least 20% by weight. 20% by weight
If it is less than the above range, the physical property level of the composition after crosslinking modification is insufficient, which is not preferable.

The component (a) other than the random copolymer is a crystalline propylene polymer. Here, "crystalline" means an X-ray diffraction method (for propylene polymer resin, G. Natta et al., Rend. Accad, Naz. Lincei. 22 (8), 1
1 (according to the method of 1957)) has a crystallinity of 20% or more. The term "propylene polymer" refers to a homopolymer of propylene as well as a copolymer of propylene and another monomer copolymerizable therewith, and thus homopolymer of propylene. It may be a polymer, a copolymer of propylene and an α-olefin containing ethylene, such as a random or block copolymer, or a mixture thereof. In the case of a copolymer, the α-olefin is not limited to two types, and may be a plurality of three or more types. Among these, copolymers or homopolymers containing a majority of propylene are preferable, and among them, crystalline propylene-based polymers, that is, crystalline propylene homopolymer, crystalline propylene-ethylene block or random copolymer, It is preferable in terms of balance of mechanical properties. These polymers can be obtained by polymerization or modification by a known method, but they can also be appropriately selected and used from commercially available products. Of course, they can be used together.

The melt flow rate (MFR, 230 ° C., load 2.16 kg) of the crystalline propylene polymer is 0.01.
To 400 g / 10 minutes is preferable, and 0.15 to 30
The range of 0 g / 10 minutes is more preferable, and especially 0.5-
A range of 200 g / 10 minutes is preferred. The value of MFR is 0.
If it is less than 01 g / 10 min, molding workability tends to be difficult, and if it is more than 400 g / 10 min, the mechanical strength level is low, which is not preferable.

[Production of Copolymer Resin] [I] Polymerization Catalyst The random copolymer of the present invention comprises a Ziegler-type stereoregular rule formed from a known reduced highly active titanium trichloride composition and an organoaluminum compound. Of a given monomer in the presence of a neutral catalyst or a solid titanium catalyst component containing titanium, magnesium, halogen and an electron donor as essential components, and a Ziegler type stereoregular catalyst formed from an organoaluminum compound. Is usually polymerized to produce.

Among these, titanium, magnesium,
It is preferable to use a Ziegler type stereoregular catalyst formed from a solid titanium catalyst component containing halogen and an electron donor as essential components and an organoaluminum compound which is a cocatalyst because the soluble by-product polymer is small.

[II] Random Copolymerization A random copolymer is produced by mixing and contacting an α-olefin with a non-conjugated diene and, if necessary, ethylene in the presence of the above-mentioned known Ziegler-type stereoregular catalyst. Random copolymerization. The amount ratio of each monomer in the random copolymerization system does not need to be constant over time, it is convenient to supply each monomer at a constant mixing ratio, and the mixing ratio can be changed over time. It is possible. Further, in consideration of the copolymerization reaction ratio, any of the monomers, particularly non-conjugated dienes, may be added in a divided manner.

As the polymerization mode, any mode can be adopted as long as the catalyst component and each monomer are efficiently contacted with each other.
Specifically, a slurry method using an inert solvent, a slurry method using an α-olefin and a non-conjugated diene as a solvent without substantially using an inert solvent, or each monomer without substantially using a liquid solvent. It is possible to employ a gas phase method or the like that keeps the gas in a substantially gaseous state.

The polymerization conditions are not necessarily the same depending on the process employed, but the polymerization temperature is 30 to 100 ° C., preferably 40 to 90 ° C., particularly preferably 50 to 80 ° C., and the polymerization pressure is 0 to 45 kg /. cm ² G, preferably 1
40 kg / cm ² G, particularly preferably 2-36 kg / cm ² G,
Is appropriate.

The control of the molecular weight of the copolymer can be carried out by various known techniques, but in practice, the control of the molecular weight by hydrogen is most preferable. Also, before carrying out the random copolymerization,
It is also possible to polymerize a small amount of a single α-olefin to improve productivity. The α-olefin used here may be the same as or different from the α-olefin which is the main component of the copolymer.

<Component (b)> The olefin copolymer rubber used in the present invention means an elastic copolymer containing olefin as a main component. For example, there are ethylene-propylene copolymer rubber, ethylene-propylene-non-conjugated diene copolymer rubber, and ethylene-butene-non-conjugated diene copolymer rubber. Among these, ethylene-propylene-non-conjugated diene copolymers are preferable from the viewpoint of crosslinking rate. Non-conjugated dienes include dicyclopentadiene, 1,4-hexadiene, methylene norbornene, ethylidene norbornene and the like. Of these, ethylidene norbornene is preferred.

The weight ratio of ethylene / propylene in the copolymer rubber is 50/50 to 90/10, preferably 60.
/ 40 to 80/20. The content of the non-conjugated diene is 1-35 as an iodine value, preferably 5-20. The Mooney viscosity (ML _{1 + 4} 100 ° C.) of the copolymer rubber at 100 ° C. is 40 to 350, preferably 6
0-200, Mooney viscosity by ML _{1 + 8} (120 ° C.) is 30-300, preferably 40-200. When the iodine value is 1 or less or ML _{1 + 4} 100 ° C. is 40 or less, the crosslinking level of the copolymer rubber is low and the mechanical strength is not sufficient. Iodine value over 35 or ML _{1 + 4} 100 ℃
If the value is 350 or more, the moldability is low and there is a problem.

<Component (c)> The mineral oil-based softening agent used in the present invention imparts plasticity to the olefin-based copolymer rubber (component (b)), and finally, the thermoplastic elastomer composition. It is used to improve moldability, hardness, flexibility and the like. In the present invention, high-boiling fractions of petroleum such as paraffin-based, naphthene-based, and aromatic-based (average molecular weight of 30
0-1500 and a pour point of about 0 ° C. or lower) can be used. From the viewpoint of the absorption rate of the mineral oil type softening agent to the olefin type copolymer rubber and the color stability of the resulting thermoplastic elastomer, the paraffin type is preferable.
Further, the viscosity-specific gravity constant, which is a function of oil composition, is 0.79.
0 to 0.849 is preferable. This mineral oil-based softening agent may be used by being preliminarily absorbed by the copolymer rubber and in the form of an oil-extended olefin-based copolymer rubber.

<Crosslinking Agent> As the crosslinking agent, those conventionally used for olefin copolymer rubbers can be used alone or in combination. As a preferable crosslinking agent,
(A) Organic peroxides, (b) sulfur compounds, (c) quinone dioximes such as p-quinone dioxime, p-quinone dioxime benzoate, (d) alkylphenol-formaldehyde resins, brominated alkylphenol-formaldehyde resins Methylol phenolic resins such as
(E) Metal halides and the like. Among these crosslinking agents, organic peroxides, sulfur compounds and methylolphenol resins are preferred.

When the crosslinking agent is used, it is preferable to use a crosslinking aid or a crosslinking accelerator together in order to promote the crosslinking efficiently. When the organic peroxide is used as a crosslinking agent, preferred organic peroxides are 1,1-di (t-butylperoxy) 3,5,5-trimethylcyclohexane, dicumyl peroxide and 2,5- There are dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, etc., of which 2,5-dimethyl-2 , 5-di (t-
Butyl peroxy) hexane is preferred.

As the crosslinking aid for the organic peroxide, N,
N'-m-phenylene bismaleimide, p-quinone dioxime, divinylbenzene, ethylene glycol dimethacrylate, allyl methacrylate and the like are preferable.

When a sulfur compound is used as a cross-linking agent, the cross-linking accelerator and the cross-linking aid include (i) thiurams such as tetramethylthiuram disulfide and tetraethylthiuram disulfide, (b) mercaptobenzothiazole, dibenzothiazyl disulfide. Such as thiazoles, (c) diphenylguanidine, guanidines such as di-o-tolylguanidine, (d) acetaldehyde aniline, butyraldehyde aniline and other aldehyde amines, (f) zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, etc. Dithiocarbamates,
(F) Zinc oxide, active zinc and the like, and (to) stearic acid, oleic acid, zinc stearate and the like, which can be used alone or in combination of two or more kinds.

When a methylolphenol resin is used as a cross-linking agent, examples of the cross-linking aid include (a) stannous chloride,
Metal halides such as ferric chloride and zinc chloride, and organic halides such as (b) brominated butyl rubber and chlorinated polypropylene are preferable.

(2) Composition Ratio of Constituent Components The proportion of each component in the thermoplastic elastomer composition of the present invention is shown below. The ranges of the component (a), the component (b) and the component (c) are 10 to 70% by weight, 15 to 50% by weight and 15 to 45% by weight, respectively, and preferably 10 to 60% by weight and 20 to 45% by weight. %, 20 to 45% by weight, particularly preferably 15 to 50% by weight, 25 to 40% by weight, 2
5 to 45% by weight. When the content of the random copolymer as the component (a) is 70% by weight or more or the content of the olefin copolymer rubber as the component (b) is 15% by weight or less, the elastomer properties such as compression set and hardness decrease, and the component If (a) is less than 10% by weight, component (b) is more than 50% by weight, and component (c) is less than 15% by weight, moldability is insufficient,
If the content of component (c) exceeds 45% by weight, mechanical strength is insufficient, which is not preferable.

The compounding amount of the crosslinking agent is 0.01 to 5 parts by weight, preferably 0.02 to 2 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). The amount of the crosslinking aid compounded is 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight. The crosslinking agent and the crosslinking aid are
Involved in the intramolecular reaction of the olefin copolymer rubber and the intermolecular reaction with the specific propylene copolymer,
If it is less than 0.01 parts by weight or less than 0.05 parts by weight, the improvement effect is small, while if it exceeds 5 parts by weight, moldability and the like are deteriorated, which is not preferable.

The thermoplastic elastomer composition thus obtained has a gel fraction, that is, an olefin-based copolymer of the cyclohexane-insoluble matter in the olefin-based copolymer rubber produced by dynamically heat-treating and crosslinking. The ratio to the polymer rubber is preferably 50% by weight or more, more preferably 65% by weight or more. When the gel fraction is less than 50% by weight, the level of compression set is insufficient, which is not preferable. The detailed method for measuring the gel fraction will be described later.

(3) Production of composition The term "dynamically heat-treated and crosslinked" in the present invention means
It means that the composition is cross-linked by melt kneading in the presence of a cross-linking agent (and usually a cross-linking aid) under a predetermined temperature condition (usually 150 to 250 ° C.) to lower its fluidity.

When blending the components (a) to (c) and the crosslinking agent in order to obtain the thermoplastic elastomer composition of the present invention, various devices can be used. For example, melt kneading can be performed with a roll, a Banbury mixer, a single screw extruder, a twin screw extruder, or the like. In the present invention, it is preferable to knead under a nitrogen gas atmosphere. The melt-kneading temperature is usually 150 ° C to 250 ° C, preferably 160 ° C to 23 ° C.
The range is 0 ° C.

In the blending method, first, the components (a) and (b) are melt-kneaded, and then the cross-linking agent (and the cross-linking aid) is added and melt-kneaded, and then the component (c) is added. Further, there is a method of melt-kneading. However, when the amount of the component (c) is large in this method, it takes a long time to impregnate and disperse the component (c) in the component (b). ), (B) and (c) are melt-kneaded to be uniformly plasticized, and then a cross-linking agent (and a cross-linking auxiliary agent) is added to the plasticized product in the molten state and further kneaded to cross-link the olefin copolymer rubber. Cause.

[0048]

The following examples are intended to illustrate the present invention. These examples are merely illustrative and therefore do not limit the scope of the invention. Details of the polymer components used are as follows.

(1) Raw Material Component (a) a-1: A random copolymer containing 7-methyl-1,6-octadiene.

[Preparation of Supported Catalyst] 100 ml of dehydrated and deoxygenated n-heptane was introduced into a flask sufficiently purged with nitrogen, and then 0.1 mol of MgCl ₂ and Ti (O.nC ₄ H ₉ ) _{4 were} added. 0.20 mol of was introduced and reacted at 100 ° C. for 2 hours. 40 after completion of the reaction
The temperature was lowered to ° C, 15 ml of methylhydrogenpolysiloxane was introduced, and the reaction was carried out for 3 hours. After completion of the reaction, the produced solid component was washed with n-heptane and a part thereof was taken out for composition analysis.
Ti = 15.2 weight percent and Mg = 4.2 weight percent. 100 ml of dehydrated and deoxygenated n-heptane was introduced into a flask sufficiently replaced with nitrogen, and 0.03 mol of the component synthesized above was introduced in terms of Mg atom. Further, 0.05 mol of SiCl ₄ was introduced at 30 ° C. for 15 minutes and reacted at 90 ° C. for 2 hours. After completion of the reaction, it was washed with purified n-heptane. Then n
-Ortho-C ₆ H ₄ (CO
Cl) ₂ 0.004 mol and introduced at 50 ° C., then 0.05 mol SiCl ₄ introduced and 90 ° C.
And reacted for 2 hours. After completion of the reaction, it was washed with n-heptane to obtain a catalyst component. The Ti content was 2.05 weight percent.

[Production of Copolymer] After replacing the autoclave having a capacity of 1 liter with propylene, n-heptane 3 was added.
30 ml was charged, and 0.1 g of triethylaluminum and 0.07 g of a catalyst with a carrier prepared by the above method were added in this order. Next, 125 N ml of hydrogen was added, propylene was then injected under pressure, and the mixture was stirred at 50 ° C. and 0.5 kg / cm ² G. After that, 70 ml of 7-methyl-1,6-octadiene was added, and the temperature was raised while pressurizing propylene to 65 ° C. and 5.5.
Polymerization was carried out for 5 hours while maintaining kg / cm ² G. Then, after deactivating the catalyst with n-butanol, the catalyst residue was extracted with water and the copolymer was recovered by centrifugation and dried. As a result, 194 g of dry powder was obtained. The bulk density was 0.50 g / cc. In addition, the amorphous polymer is 5.4.
It was g.

The MFR of this copolymer is 3.5 g / 10.
Min, the melting peak by DSC was 149.1 ° C.
Moreover, by analysis by H ¹ -NMR, 7-methyl-1,
The content of 6-octadiene was 2.6 mol%, there was no chain of this diene monomer unit, and it was a 1,2-addition structure. The crystallinity by X-ray diffraction was 38.0%. Flexural modulus according to JIS K-7203 is 6
It was 250 kg / cm ² .

A-2: A mixture of 50 parts by weight of a propylene copolymer containing 0.4 mol% of divinylbenzene and 50 parts by weight of a propylene copolymer containing 4 mol% of 7-methyl-1,6-octadiene. ..

(1) Synthesis of divinylbenzene-containing propylene copolymer n-heptane 5 dehydrated and deoxygenated after repeating propylene substitution in an autoclave having an internal volume of 100 liters
0 liter, divinylbenzene (manufactured by Tokyo Kasei Co., Ltd.)
4.5 liters, diethyl aluminum chloride 23.
4 g and titanium trichloride (Tyo Toufa Co., Ltd. "T
TA-12 ") was introduced, 45 liters of hydrogen was further added, and the mixture was pressurized with propylene to a total pressure of 5 kg / cm ² G and polymerization was carried out at 65 ° C for 3 hours.

After completion of the polymerization, the reaction mixture was filtered to obtain 11.6 kg of a copolymer polymer. When the content of divinylbenzene in the copolymer polymer was measured by analyzing the resulting copolymer polymer by an ultraviolet spectrum method,
It was 0.4 mol%.

(2) Synthesis of propylene copolymer containing 7-methyl-1,6-octadiene [Preparation of catalyst with carrier] 1 liter of dehydrated and deoxygenated n-heptane was introduced into a flask sufficiently replaced with nitrogen.
Then 1.0 mol of MgCl ₂ and Ti (O.nC ₄
H _{9) 4-reacted} for 2 hours at 2.0 mol introduced to 100 ° C.. After the reaction was completed, the temperature was lowered to 40 ° C., 150 ml of methylhydrogenpolysiloxane was introduced, and the reaction was carried out for 3 hours. After completion of the reaction, the produced solid component was washed with n-heptane, and a part thereof was taken out and analyzed for composition. Ti = 15.2% by weight and Mg = 4.2% by weight.

1 liter of dehydrated and deoxygenated n-heptane was introduced into a flask thoroughly replaced with nitrogen, and 0.3 mol of the component synthesized above was introduced in terms of Mg atom. Si
Introducing 0.5 mol of Cl ₄ at 30 ° C. for 15 minutes
The reaction was carried out at 0 ° C for 2 hours. After completion of the reaction, it was washed with purified n-heptane. Then, 250 ml of n-heptane was mixed with 0.04 mol of ortho-C ₆ H ₄ (COCl) ₂ and introduced at 50 ° C., and then 0.5 mol of SiCl ₄ was introduced and reacted at 90 ° C. for 2 hours. After the reaction is completed, n
-Washed with heptane to give the catalyst component. The Ti content was 2.03 weight percent.

[Manufacture of Copolymer] After replacing the autoclave having a capacity of 100 liters with propylene, 30 liters of n-heptane was charged and triethylaluminum was added.
0 g, 4.0 g of diphenyldimethoxysilane and 10.0 g of the carrier-supported catalyst prepared by the above method were added. Next, after adding 12.5 liters of hydrogen, propylene was injected under pressure and stirred at 50 ° C. and 0.5 kg / cm ² G. After this, 7
-Methyl-1,6-octadiene (12 liters) was added, and the temperature was raised while pressurizing propylene at 70 ° C and 7 kg / cm.
Polymerization was carried out while holding at ² G. Then, after deactivating the catalyst with n-butanol, the catalyst residue was extracted with water, the copolymer was recovered by centrifugation and dried. 19.3 kg of dry powder was obtained.

The melting peak of this copolymer by DSC was 152.3 ° C. The content of 7-methyl-1,6-octadiene Analysis by H ¹ -NMR 4.
It was 0 mole percent.

A-3: A random copolymer containing 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene. After replacing the autoclave having a volume of 1 liter with propylene, an 8: 2 (molar ratio) mixture of 4-methyl-1,4-hexadiene and 5-methyl-1,4-hexadiene 40
0 ml was charged, and 0.9 g of triethylaluminum and 0.4 g of the carrier-supported catalyst prepared by the above method were added in this order. Next, after adding 500 Nml of hydrogen, propylene was injected under pressure and stirred at 25 ° C. and 2.5 kg / cm ² G. After that, the temperature is raised while pressing in propylene, and the temperature is 65 ° C. and 8 kg /
Polymerization was carried out for 2 hours while holding at cm ² G. Then, 114 g of dry powder was obtained in the same manner as described above. The bulk density was 0.41 g / cc.

The MFR of this copolymer was 2.2 g / 10.
Min, the melting peak by DSC was 152.0 ° C. The content of methyl-1,4-hexadiene was 3.8 mol% as analyzed by H ¹ -NMR, and there was no chain of this diene monomer unit, and it was a 1,2-addition structure. The crystallinity by X-ray diffraction was 41%. J
Flexural modulus according to IS K-7203 is 5000 kg /
It was cm ² .

A-4: Polypropylene resin manufactured by Mitsubishi Petrochemical Co., Ltd. Grade name MA3 Melt flow rate 10 (g / 10 minutes) a-5: Polypropylene resin manufactured by Mitsubishi Petrochemical Co., Ltd. Grade name MA8 Melt flow rate 0. 6 (g / 10 minutes)

Component (b) b-1: An oil-extended rubber obtained by previously mixing an ethylene-propylene-ethylidene norbornene resin manufactured by Nippon Synthetic Rubber Co., Ltd. with the mineral oil-based softening agent of component (c) by 43% by weight. Mooney viscosity: ML _{1 + 8} (120 ° C.) 62 Iodine number: 15 b-2: Ethylene-propylene-ethylidene norbornene resin manufactured by Nippon Synthetic Rubber Co., Ltd. Grade name: EP57P Mooney viscosity: ML _{1 + 4} (100 ° C) 88 Iodine number: 15

Component (c) Paraffin-based softener manufactured by Idemitsu Kosan Co., Ltd., trade name “Diana Process Oil PW-380”

(2) Evaluation Melt flow rate According to JIS K-7210, it was measured at 230 ° C. under a load of 5 g. (G / 10 minutes) Tensile property A granular thermoplastic elastomer composition is molded by a small injection molding machine (Minimax), and is subjected to JIS K-711 at 23 ° C.
It measured according to 3. (Strength at break kgf / cm ² ) (Elongation at break%) Hardness It was measured with a type A tester according to JIS K-6301.

A sheet having a gel fraction of 50 mm × 50 mm × a thickness of 0.2 mm was press-molded and immersed in cyclohexane at 23 ° C. for 72 hours to measure the amount of rubber extracted from the test piece. I asked. It was confirmed that the mineral oil-based softening agent was completely extracted under the present extraction conditions. Therefore, the gel fraction was calculated by correcting the amount of rubber extracted by calculation.

Compression set According to JIS K-6301, 70 ° C., 22 hours, 25
It was measured after the% compression test. (%). Oil bleeding 20mm x 20mm x 4mm sheet is press-formed at 75 ℃
After being left in the oven for 24 hours, the oil bleeding on the surface of the sheet was judged visually and by a finger contact method.

Examples 1 to 9 According to the composition shown in Table 1, random copolymer a-1, propylene polymer a-3, olefin copolymer rubber b-1, and mineral oil softening agent c were blended with a mixer. Then 200
The mixture was fed at 10 kg / hr to a twin-screw kneading extruder having a diameter of 30 mm and rotating at 200 rpm at the same temperature of 10 rpm, and was plasticized and kneaded to obtain a granular cooled product (first step). Table 1 shows the obtained granules.
Add a predetermined amount of the cross-linking agent and the cross-linking aid according to
The same twin-screw kneading extruder set at 0 ° C. and 250 rpm was fed at 5 kg / Hr and plasticized and kneaded to obtain a granular cooled product (second step).

Comparative Examples 1 to 10 The same operations as in Examples 1 to 9 were repeated according to the compositions shown in Table 2 to obtain granular cooled products.

Example 10 Random copolymer a-2, polypropylene a-5 and olefinic copolymer rubber b-2 having the composition shown in Table 1 were used under a nitrogen atmosphere using a Brabender Plastograph under a nitrogen atmosphere 190.
The mixture was kneaded at 160 ° C. and 5 minutes for 5 minutes (first step). Next, a cross-linking agent and a cross-linking aid were added and kneading was performed for 10 minutes (second step). Next, the mineral oil-based softening agent c was added to the kneaded product after the completion of the second step, and the mixture was kneaded using a Brabender Plastograph at 210 ° C. and 80 rpm for 5 minutes (third step). The resulting kneaded product was pulverized to obtain a granular composition.

Comparative Example 11 A composition was obtained in the same manner as in Example 10 except that the random copolymer was not used according to the composition shown in Table 3. The following Table 3 and Table 4 show the results of the above Examples and Comparative Examples.

[0072]

[Table 1]

(Note) 1. The components (a), (b) and (c) represent% by weight, and the crosslinking agent and the crosslinking aid represent parts by weight per 100 parts by weight of the components (a), (b) and (c) in total. .. 2. In Examples 1 to 9, the components (a), (b) and (c) were kneaded together (first step), and then a cross-linking agent and a cross-linking aid were added and kneaded (second step). Example 1
In 0, the components (a) and (b) were kneaded (first step)
Then, a cross-linking agent and a cross-linking aid are added and kneaded (second step), and then the component (c) is added and kneaded (third step).
did.

3. The cross-linking agents and cross-linking aids used are as follows. * 1 t-butyl peroxybenzoate * 2 divinylbenzene * 3 brominated alkylphenol formaldehyde resin * 4 di-t-butyl peroxide * 5 N, N'-meta-phenylene-dimaleimide

[0075]

[Table 2]

1. Components (a), (b) and (c)
Represents% by weight, and the cross-linking agent and the cross-linking aid are the components (a),
Parts (b) and (c) are shown per 100 parts by weight in total. 2. In Comparative Examples 1 to 10, the components (a) and (b)
And (c) were collectively kneaded (first step), and then a cross-linking agent and a cross-linking aid were added and kneaded (second step). In Comparative Example 11, components (a) and (b) were kneaded (first step), then a cross-linking agent and a cross-linking aid were added and kneaded (second step), and then component (c) was added. And kneaded (the third step).

3. The cross-linking agents and cross-linking aids used are as follows. * 1 t-butyl peroxybenzoate * 2 divinylbenzene * 3 brominated alkylphenol formaldehyde resin * 4 di-t-butyl peroxide * 5 N, N'-meta-phenylene-dimaleimide

[0078]

[Table 3]

[0079]

[Table 4]

[0080]

EFFECTS OF THE INVENTION The thermoplastic elastomer composition according to the present invention has excellent physical property level and balance in hardness, moldability, mechanical strength and compression set. It has been described in the section above.

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Claims (1)

What is claimed is: 1. A mixture of the following components (a), (b) and (c) which is dynamically heat treated in the presence of a crosslinking agent to crosslink. And a thermoplastic elastomer composition. Component (a) at least one α-olefin having 3 to 12 carbon atoms;
At least 1 selected from the following formula (1) and formula (2)
A random copolymer of certain non-conjugated dienes and optionally ethylene, wherein the content of non-conjugated dienes in the copolymer is 0.1 to 15 mol% and crystallized by X-ray diffractometry 20% or more, melt flow rate 0.01 to 200
g / 10 minutes, and elastic modulus according to JIS K7203 is 1
Mixture with a crystalline propylene polymer containing at least 20% by weight of a random copolymer of 000 to 30,000 kg / cm ² 10 to 70% by weight (In the formula, R ¹ represents an alkyl group having 1 to 8 carbon atoms, R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, provided that R ² and R ³ are both hydrogen. It is not an atom, and n represents a number from 2 to 10.) (In the formula, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrocarbon group having 1 to 6 carbon atoms, and m represents a number of 0 or 1.) Component (b) Olefin-based copolymer rubber 15 -50% by weight Component (c) Mineral oil-based softener 15-45% by weight