JP6519271B2 - Olefin-based thermoplastic elastomer composition - Google Patents

Description

  The present invention relates to an olefin-based thermoplastic elastomer composition, and more particularly to an olefin-based thermoplastic elastomer composition capable of providing a molded article excellent in tensile strength, elongation at break and rubber elasticity. .

  Olefin-based thermoplastic elastomers are widely used as energy- and resource-saving elastomers, particularly as substitutes for vulcanized rubber, in automobile parts, industrial machine parts, electronic / electrical equipment parts, construction materials and the like.

  The olefin-based thermoplastic elastomers can be divided into crosslinked and non-crosslinked types. Generally, non-crosslinkable thermoplastic elastomers have little variation in quality because they do not involve a crosslinking reaction, and are inexpensive in manufacturing cost, but comparing them in terms of performance, tensile strength, elongation at break, or rubbery properties (for example, The crosslinkable olefin-based thermoplastic elastomer is superior to the non-crosslinkable olefin-based thermoplastic elastomer in terms of permanent elongation, compression set, and heat resistance. As a crosslinkable thermoplastic elastomer, a composition in which a specific amount of EPDM rubber or the like is contained in a crystalline polyolefin resin such as PP is known (patent documents 1 and 2), but the low temperature characteristics than conventionally known vulcanized rubber There is a need for the emergence of olefinic thermoplastic elastomer compositions that can provide molded articles excellent in tensile strength, elongation at break and rubbery properties.

Japanese Patent Application Laid-Open No. 09-012790 JP 2000-186174 A

  An object of the present invention is to provide an olefin-based thermoplastic elastomer composition capable of providing a molded article excellent in low temperature properties, tensile strength, elongation at break and rubbery properties than conventional crosslinked olefin-based thermoplastic elastomers. It is to do.

  As a result of intensive studies to solve the above problems, the present inventors have found that ethylene · α− having characteristics such as specific density, molecular weight distribution, number of unsaturated bonds, and the like polymerized using a metallocene catalyst as a soft resin component. It has been found that by selecting an olefin copolymer, a molded article excellent in low temperature characteristics, tensile strength, elongation at break and rubbery properties can be provided, and the present invention has been completed.

That is, according to a first aspect of the present invention, there is provided an olefin-based thermoplastic elastomer composition characterized by the following.
A polypropylene resin (A) and an ethylene / α-olefin copolymer (B) which is a copolymer of ethylene and one or more kinds of α-olefins of 3 to 20 carbon atoms, (A) and 10 parts by weight or more and 60 parts by weight or less of (A) and 40 parts by weight or more and 90 parts by weight or less of (B) based on 100 parts by weight of the total amount of (B),
An olefin-based thermoplastic elastomer composition characterized in that the ethylene / α-olefin copolymer (B) has the following characteristics (b1) and (b2).
(B1) The density is 0.860 to 0.920 g / cm ^3. (B2) The number of branches (N) by the comonomer in the ethylene / α-olefin copolymer, and the total number (V) of vinyl and vinylidene The relationship of the formula (1) is satisfied, and the numbers of vinyl and vinylidene are each 0.05 or more.
Formula (1): N × V ≧ 15
(However, N and V are the number per total of 1000 carbons of the main chain and side chains measured by NMR.)

Furthermore, according to the second invention of the present invention, the olefin-based thermoplastic elastomer composition according to the first invention, wherein the ethylene / α-olefin copolymer (B) further satisfies the following (b3): The goods are provided.
(B3) The total number of vinyl and vinylidene double bonds in the ethylene / α-olefin copolymer is the total number of total double bonds (vinyl, vinylidene, cis-vinylene, trans-vinylene, trisubstituted olefin) 55% or more (However, the number of vinyl, vinylidene, cis-vinylene, trans-vinylene and trisubstituted olefin is the number per total of 1000 carbon atoms of the main chain and side chains measured by NMR)

  Further, according to the third invention of the present invention, in the first or second invention, the ethylene / α-olefin copolymer (B) further has a total number of vinyl and vinylidene in (B) being NMR. The olefin-based thermoplastic elastomer composition is provided, wherein the main chain and the side chains are at least 0.2 per 1000 carbon atoms in total.

  Further, according to the fourth invention of the present invention, the ethylene-α-olefin copolymer (B) is produced by using a metallocene catalyst, The olefin system according to any one of claims 1 to 3, characterized in that A thermoplastic elastomer composition is provided.

  Further, according to the fifth invention of the present invention, the ethylene / α-olefin copolymer (B) contains 10 to 30% by mole of propylene as at least one component of α-olefin. An olefin-based thermoplastic elastomer composition according to any one of to 4 is provided.

  Further, according to the sixth aspect of the present invention, 2 to 100 parts by weight of a softener (based on 100 parts by weight of the total amount of the polyolefin resin (A) and the ethylene / α-olefin copolymer (B)) The olefin-based thermoplastic elastomer composition according to any one of claims 1 to 5, which contains C).

  Moreover, according to the seventh invention of the present invention, the thermoplastic elastomer composition according to any one of claims 1 to 6 is characterized in that the thermoplastic elastomer composition is crosslinked. To be

  The olefin-based thermoplastic elastomer composition of the present invention can be selected from the group consisting of an ethylene / α-olefin copolymer satisfying a specific condition with respect to the number of branches and the number of vinyl and vinylidene as a soft component. It is possible to provide an olefin-based thermoplastic elastomer composition capable of providing a molded article excellent in mechanical properties, heat resistance and low temperature properties.

  The present invention relates to a novel olefin-based thermoplastic elastomer composition comprising a specific ethylene / α-olefin copolymer as a soft component.

Hereinafter, each component used in this invention and the resin composition obtained are demonstrated in detail.
The polypropylene-based resin (A) in the present invention may be a polypropylene-based resin conventionally used as a crystalline resin of an olefin-based thermoplastic elastomer composition. Specifically, isotactic homopolypropylene, syndiotactic It is a random or block copolymer of homopolypropylene or an α-olefin such as ethylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1 and propylene, and the crystal component is polypropylene. In addition to these α-olefins, known monomers such as a diene compound may be copolymerized as long as the effects of the invention are not impaired. Moreover, these alpha-olefins may be used individually or in mixture of 2 or more types. Furthermore, polypropylene resins may be used alone or in combination of two or more. These representative resins are commercially available.
The polymerization mode may be random type or block type, and any polymerization mode may be adopted as long as a resinous material is obtained. These polypropylene resins may be used alone or in combination of two or more. The polypropylene-based resin (A) used in the present invention preferably has a MFR (ASTM D 1238-65T, 230 ° C.) in the range of usually 0.01 to 100 g / 10 min, particularly 0.05 to 50 g / 10 min. .
The polypropylene-based resin (A) has a role of improving the flowability and heat resistance of the composition. In the present invention, the polypropylene resin (A) is 10 parts by weight or more and 60 parts by weight or less with respect to 100 parts by weight in total of the polypropylene resin (A) and the ethylene / α-olefin copolymer (B), Preferably, it is used in a proportion of 20 to 50 parts by weight. In addition, this quantity shows the total amount, when using in mixture of 2 or more types as polypropylene resin.
When a polypropylene resin (A) is used in the proportion as described above, an olefin thermoplastic elastomer composition excellent in rubber elasticity and excellent in molding and processing can be obtained.

(I) Physical Properties of Component (B) The ethylene / α-olefin copolymer (B) in the present invention is an ethylene / α-olefin copolymer comprising ethylene and an α-olefin having 3 to 20 carbon atoms (B Is characterized by having the following characteristics (b1) and (b2).
(B1) The density is 0.860 to 0.920 g / cm ^3. (B2) The number of branches (N) by the comonomer in the ethylene / α-olefin copolymer, and the total number (V) of vinyl and vinylidene The relationship of the formula (1) is satisfied, and the numbers of vinyl and vinylidene are each 0.05 or more.
Formula (1): N × V ≧ 15
(However, N and V are the number per total of 1000 carbons of the main chain and side chains measured by NMR.)

(B1) Density The ethylene / α-olefin copolymer used in the present invention has a density of 0.860 to 0.920 g / cm ³ , preferably 0.865 to 0.910 g / cm ³ , more preferably 0. It is .870 to 0.900 g / cm < ³ >. When the density of the ethylene / α-olefin copolymer is less than 0.860 g / cm ^{3, the} adhesion of the resin pellets becomes strong and the handling becomes worse, and when the density exceeds 0.920 g / cm ³ , the olefin thermoplastic elastomer composition It is not preferable because the flexibility of the
In order to adjust the density of the polymer, a method of appropriately adjusting the content of the α-olefin which is a comonomer, the polymerization temperature, the amount of the catalyst, etc. is taken. The density of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 annex (in the case of low density polyethylene) (23 ° C.)

(B2) Relationship between Number of Branches (N) by Comonomer and Number of Vinyl and Vinylidene (V) The ethylene / α-olefin copolymer used in the present invention is the total number of branches (N) and vinyl and vinylidene by a comonomer. It is important that (V) satisfy the following formula (1).
Formula (1): N × V ≧ 15
Here, the number of branches (N) and the number of vinyl and vinylidene (V) are the number per total carbon number of 1000 of the main chain and side chains measured by NMR (number / total 1000 C).

  In the olefin-based thermoplastic elastomer composition of the present invention, a molding excellent in low temperature properties, tensile strength, elongation at break and rubbery properties is obtained by crosslinking the ethylene / α-olefin copolymer (B) which is a soft component. The crosslinking properties of the ethylene / α-olefin copolymer (B) are very important because a body is obtained.

  The present inventors changed ethylene · α-in which the polymerization conditions such as the temperature of the polymerization process, the type of catalyst used in the polymerization, the type of comonomer used and the amount thereof were changed in the production of ethylene and the α-olefin copolymer. As a result of intensively studying various olefin copolymers, as a cross-linking ethylene / α-olefin copolymer having both cross-linking properties and mechanical strength, it is included in 1) ethylene / α-olefin copolymer Among the double bonds, vinyl and vinylidene are important for the development of crosslinking properties, and 2) when the total number of vinyl and vinylidene and the number of branches of the polymer satisfy the above formula (1) It is preferable that the total number of vinyl and vinylidene groups be in a specific range, and furthermore, the number of vinyl and vinylidene groups is 0.2 per 1000 carbon atoms in the main chain and side chains measured by NMR Improvement in particular cross-linking efficiency when satisfying not less than can be achieved.

The number of branching (N) by the comonomer in the polymer indicates the amount of tertiary carbon contained in the polymer, and is the number per total of 1000 carbon atoms of the main chain and side chains measured by NMR. E.g. W. Hansen, R. Blom, and O. M. It can be calculated from ¹³ C-NMR spectrum with reference to Bade, Polymer, 36, 4295 (1997).
In addition, the number of these double bonds is the number per total of 1000 carbon atoms in the main chain and side chains, and was calculated using the integrated intensities of the characteristic peaks of ¹ H-NMR spectrum and ¹³ C-NMR spectrum .
Specifically, the number of vinyls per 1000 carbons was calculated from the peak area derived from a saturated alkyl chain appearing between chemical shifts of 0.4 to 2.8 ppm and the peak area derived from vinyl around 4.9 ppm. Moreover, the number of vinylidenes was calculated using the characteristic peak around 4.7 ppm.

The number of branches (N) due to the comonomer in the polymer can be adjusted by the addition amount of α-olefin at the time of production, polymerization conditions such as polymerization temperature and the like.
The number of branches (N) of the polymer of the present invention is 0 <N, preferably 20 <N, more preferably 40 <N, most preferably 60 <N, and the upper limit is not particularly limited. Preferably, it is in the range of N <140, more preferably N <120, and most preferably N <100.
The value of N × V is preferably in the range of preferably N × V ≧ 15, more preferably N × V ≧ 40, and the upper limit is not particularly limited as long as it can be manufactured, but is preferably N × V. The range of ≦ 200, more preferably N × V ≦ 160 can be mentioned.
The total number of vinyl and vinylidene can be controlled within the above range by appropriately selecting the appropriate metallocene catalyst, polymerization temperature and type of comonomer.
Further, the number of vinyl and vinylidene can be adjusted under production conditions such as polymerization temperature or by using a diene compound as a comonomer.

(B3) Kind of double bond and ratio thereof The total number of vinyl and vinylidene in the ethylene / α-olefin copolymer used in the present invention is preferably all doubles in the ethylene / α-olefin copolymer It occupies 55% or more, preferably 60% or more, more preferably 65% or more, and most preferably 70% or more of the total number of bonds (vinyl, vinylidene, cis-vinylene, trans-vinylene, trisubstituted olefin). When the total number of vinyl and vinylidene is 55% or more of the total number of double bonds, the ethylene / α-olefin copolymer (B) has excellent crosslinking speed, so low temperature characteristics, tensile strength, breakage It becomes an olefin-based thermoplastic elastomer excellent in elongation and rubbery properties, and if it is less than 55%, the crosslinking rate will not be sufficient, and the physical properties of the resulting olefin-based thermoplastic elastomer will deteriorate.

(B4) Type and Amount of Double Bond In the present invention, the total number of vinyl and vinylidene as long as the number (V) of vinyl and vinylidene in the ethylene / α-olefin copolymer satisfies the formula (1). It is mentioned that the amount is 0.2 or more, preferably 0.3 or more, more preferably 0.4 or more.
As a method of adjusting the total number of double bonds, a method of appropriately selecting a suitable metallocene catalyst, a polymerization temperature, a kind of comonomer, and the like can be mentioned.

The ethylene / α-olefin copolymer used in the present invention has an MFR of 0.01 to 100 g / 10 min, preferably 0.05 to 50 g / 10 min, and more preferably 0.05 to 10 g / 10 min. is there. If the MFR of the ethylene / α-olefin copolymer is less than 0.01 g / 10 min, the molecular weight is too high and dispersion becomes difficult during kneading, while if the MFR exceeds 100 g / 10 min, the molecular weight is too low. And mechanical strength.
In order to adjust the MFR of the polymer, for example, a method of appropriately adjusting the polymerization temperature, the catalyst amount, the supply amount of hydrogen as a molecular regulator and the like can be taken. The MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS-K6922-2: 1997 Appendix (190 ° C., 21.18 N load).

(B5) Flow ratio (FR)
Ethylene · alpha-olefin copolymer used in the present invention, the _{I 10} a MFR value measured at 10kg load in the flow ratio (FR), i.e. 190 ° C., in MFR measured at 2.16kg load at 190 ° C. It is preferable that the ratio (I ₁₀ / I _2.16) to certain I _2.16 be less than 7.0. In addition, melt flow rate (MFR) is a value measured based on JIS-K7210-1999.
It is known that FR is closely correlated with the molecular weight distribution of ethylene / α-olefin copolymer and the amount of long chain branching. In the present invention, among the polymers satisfying the above conditions, the ratio ( _M10 ) at ₁₀ kg load at 190 ° C. to the MFR measurement (I _2.16 ) at _2.16 kg load at 190 ° C. It is preferred to use one having an I ₁₀ / I _2.16 ) of less than 7.0. By using a copolymer having a polymer structure characterized by such long chain branching, the balance between the rigidity and the crosslinking efficiency becomes good. On the other hand, when FR is 7.0 or more, the crosslinking efficiency at the time of crosslinking tends to deteriorate.

(B6) Ratio (Mz / Mn) of Z average molecular weight (Mz) to number average molecular weight (Mn)
When the ethylene / α-olefin copolymer used in the present invention is used for a resin composition application requiring transparency, the Z average molecular weight (Mz) determined by gel permeation chromatography (GPC) is further used. The ratio (Mz / Mn) to the number average molecular weight (Mn) is preferably 8.0 or less, more preferably 5.0 or less. When Mz / Mn exceeds 8.0, transparency is deteriorated. As a method of adjusting Mz / Mn to a predetermined range, there may be mentioned a method of selecting an appropriate metallocene catalyst and the like.

In addition, although the value of Mz and Mn is a value measured by GPC, detailed measurement conditions are as the following description.
Device: Waters company GPC 150C type detector: MIRAN company 1A infrared spectrophotometer (measurement wavelength, 3.42 μm)
Column: Showa Denko AD 806 M / S 3 columns (To calibrate the column, use Tosoh mono-dispersed polystyrene (0.5 mg / ml solution of A500, A2500, F1, F2, F4, F10, F20, F40, F288)) And the elution volume and the logarithm of molecular weight were approximated by a quadratic equation, and the molecular weight of the sample was converted to polyethylene using the viscosity equation of polystyrene and polyethylene, where the coefficient of viscosity equation of polystyrene is α 0.27, log K = -3.967, polyethylene is? = 0.733, log K =-3.407.)
Measurement temperature: 140 ° C
Concentration: 10 mg / 10 mL
Injection volume: 0.2 ml
Solvent: Ortho dichlorobenzene Flow rate: 1.0 ml / min

(Ii) Monomer Configuration of Component (B) The ethylene / α-olefin copolymer used in the present invention is one or two or more kinds of ethylene and α-olefin mainly composed of a structural unit derived from ethylene. It is a random copolymer.

The α-olefin used as the comonomer is an α-olefin having 3 to 50 carbon atoms, preferably an α-olefin having 3 to 20 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-deken, 1-undeken, 1-dodeken, vinylbenzene , 1--4-4 Methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene and the like can be mentioned. Among these, preferably, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene emissions, particularly preferably propylene.

The ethylene / α-olefin copolymer used in the present invention has an ethylene content in the copolymer of 70 to 98 mol%, preferably 75 to 95 mol%, more preferably 75 to 90 mol%. The content (in the case of two or more, the total amount thereof) is 2 to 30 mol%, preferably 5 to 25 mol%, and more preferably 10 to 25 mol%. As described above, ethylene / propylene copolymer rubber (EPR), ethylene / propylene / non-conjugated diene copolymer rubber (EPDM), etc., having an ethylene content of about 20 to 50 mol% because of the high ethylene content Is different.
When the ethylene content and the α-olefin content are in this range, the flexibility and the heat resistance after crosslinking become good. When the content of the α-olefin is too low, the transparency and flexibility of the resin may be deteriorated. On the other hand, if it is too high, the softening point of the ethylene / α-olefin copolymer is too low, so that the blocking of the pellets becomes worse and the handling becomes lacking.

In the present invention, as the α-olefin used as a comonomer of the ethylene / α-olefin copolymer, it is particularly preferable to mainly use propylene. This is because, when propylene is used as a comonomer and a high pressure ion polymerization method using a metallocene catalyst described later is employed, an ethylene / α-olefin copolymer having a particularly high total number of vinyl and vinylidene can be obtained. This effect is difficult to be obtained when an α-olefin such as 1-hexene or 1-octene is polymerized as a main comonomer component.
When propylene is used as the comonomer, the content of the comonomer derived from propylene in the ethylene / α-olefin copolymer is preferably 10 mol% or more, more preferably 10 to 30 mol%, and 10 to 25 mol%. More preferable. When the content of propylene is less than 10% by mole, the crosslinking rate may decrease due to the decrease in the number of branches.

  In addition, α-olefins used as comonomers may be used alone or in combination of two or more as long as (b1) and (b2), more preferably (b3) and (b4) are satisfied. When two α-olefins are combined to form a terpolymer, ethylene-propylene-1-butene terpolymer, ethylene-propylene-1-hexene terpolymer, ethylene-propylene-1 And-an octene terpolymer, and the like.

However, it is preferably a copolymer consisting only of one or more of ethylene and α-olefins.

(Iii) Polymerization Catalyst of Component (B) and Polymerization Method The catalyst used for producing the ethylene / α-olefin copolymer used in the present invention is not particularly limited, but a metallocene catalyst is more preferably used.

The metallocene catalyst is not particularly limited, and examples thereof include catalysts using a metallocene compound such as a zirconium compound in which a group having a cyclopentadienyl skeleton is coordinated and the like and a cocatalyst as a catalyst component. In particular, it is preferable to use a metallocene compound such as a zirconium compound in which a group having a cyclopentadienyl skeleton is coordinated.
The production method is not particularly limited, and high pressure ion polymerization method, gas phase method, solution method, slurry method and the like can be used, but the ethylene-olefin copolymer having the double bond adjusted according to the present invention is obtained. For this purpose, it is preferable to use high-pressure ion polymerization method because it is desirable to carry out the polymerization at a high temperature of 150 to 330 ° C. ("Polyethylene Technology Reader", Chapter 4, Matsuo Kazuo and Mikami Naotaka, 2001).

The olefin-based thermoplastic elastomer composition according to the present invention may contain a softening agent (C) in addition to the polypropylene-based resin (A) and the ethylene / α-olefin copolymer (B).
As a softener (C) used by this invention, the softener normally used for rubber | gum can be used. Specifically, petroleum-based substances such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum jelly; coal tar such as coal tar and coal tar pitch; castor oil, linseed oil, rapeseed oil, soybean oil, Fatty oils such as coconut oil; Waxes such as tall oil, beeswax, carnauba wax, lanolin; fatty acids such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate or their metal salts; petroleum resin, coumarone indene Synthetic polymers such as resins and atactic polypropylene; ester plasticizers such as dioctyl phthalate, dioctyl adipate and dioctyl sebacate; other microcrystalline wax, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, etc. It is below.
In the present invention, the softener (C) is preferably 2 to 100 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the total amount of the polypropylene resin (A) and the ethylene / α-olefin copolymer (B). It is used in a proportion of 5 to 80 parts by weight.
When the softener (C) is used in the proportion as described above, the resulting thermoplastic elastomer composition has excellent fluidity at the time of molding, and does not lower the mechanical properties of the molded article. In the present invention, when the amount of the softener (C) exceeds 200 parts by weight, the heat resistance and the heat aging resistance of the resulting thermoplastic elastomer composition tend to decrease.

In addition to the polypropylene-based resin (A), the ethylene / α-olefin copolymer (B) and the softening agent (C), the olefin-based thermoplastic elastomer composition according to the present invention may be an ethylene / propylene copolymer. Soft resins (D) such as rubber (EPR), ethylene / propylene / non-conjugated diene copolymer rubber (EPDM) can be included.
Specific examples of the ethylene / propylene / non-conjugated diene copolymer rubber include ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber, ethylene / propylene / dicyclopentadiene copolymer rubber and the like.
In the present invention, soft resins (D) such as ethylene / propylene copolymer rubber (EPR) and ethylene / propylene / non-conjugated diene copolymer rubber (EPDM) as described above are polypropylene resins (A) and ethylene -It is desirable to use in a ratio of preferably 5 to 200 parts by weight, more preferably 10 to 150 parts by weight with respect to 100 parts by weight of the total amount of the α-olefin copolymer (B) and the softener (C).

The olefin-based thermoplastic elastomer composition according to the present invention comprises the above-described polypropylene-based resin (A), an ethylene / α-olefin copolymer (B), and a softener (C) optionally blended. After mixing, it is obtained by dynamic heat treatment and crosslinking.
Here, "dynamically heat-treating" refers to kneading in a molten state.
In the crosslinking, an organic peroxide is used. Specific examples of the organic peroxide used in the present invention include dicumyl peroxide, di-tert-butyl peroxide, 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-butyl peroxybenzoate, tert-butyl perbenzoate Tert-Butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl chloride Ruperuokishido and the like.

Among these, in terms of odor and scorch stability, 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 is preferred, among which 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane is most preferred.
Such an organic peroxide is used in an amount of 0.02 to 3 parts by weight based on 100 parts by weight of the total amount of the material to be treated, ie, the total amount of the polypropylene resin (A) and the ethylene / α-olefin copolymer (B). Preferably, it is used in an amount of 0.05 to 1 part by weight. If the blending amount of the organic peroxide is less than the above range, the resulting thermoplastic elastomer composition has a low degree of crosslinking, so that the heat resistance, the tensile properties, the elastic recovery, the impact resilience, etc. are not sufficient. Moreover, when this compounding quantity is larger than the said range, the degree of crosslinking of the thermoplastic elastomer composition obtained may become high too much, and may bring about the fall of a moldability.

In the present invention, sulfur, p-quinonedioxime, p, p'-dibenzoylquinone dioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene in the partial crosslinking treatment with the organic peroxide. Peroxy crosslinking aids such as diphenyl guanidine, trimethylolpropane-N, N'-m-phenylene dimaleimide, or divinyl benzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tri Multifunctional methacrylate monomers such as methylolpropane trimethacrylate, allyl methacrylate and diallyl terephthalate, and polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate can be blended.
By using the above-mentioned compounds, a uniform and mild crosslinking reaction can be expected. In particular, in the present invention, triallyl cyanurate, diallyl terephthalate and divinylbenzene are most preferable.
The amount of the compound such as the above-mentioned cross-linking coagent or polyfunctional vinyl monomer is usually 2 parts by weight or less, preferably 0.3 to 2 parts by weight, per 100 parts by weight of the whole treated object Used in
Also, in order to accelerate the decomposition of organic peroxide, tertiary amines such as triethylamine, tributylamine, 2,4,6-tri (dimethylamino) phenol, aluminum, cobalt, vanadium, copper, calcium, zirconium, etc. You may use decomposition promoters, such as naphthenic acid salts, such as manganese, magnesium, lead, and mercury.

The dynamic heat treatment in the present invention is preferably performed in a non-open type apparatus, and is preferably performed in an inert gas atmosphere such as nitrogen and carbon dioxide gas. The temperature of the heat treatment is usually 150 to 250 ° C, preferably 170 ° C to 225 ° C. The kneading time is usually 1 to 20 minutes, preferably 1 to 10 minutes.
As the kneading apparatus, known mixing rolls, intensive mixers (for example, Banbury mixers, kneaders), single- or twin-screw extruders, etc. can be used, but non-open type apparatuses are preferable, especially dispersion and crosslinking of rubber components. A twin screw extruder is particularly preferred because it is easy to control.
According to the present invention, a crosslinked olefin-based thermoplastic elastomer composition comprising a polypropylene-based resin (A) and an ethylene / α-olefin copolymer (B) is obtained by the above-mentioned dynamic heat treatment.

In the present invention, that the olefin-based thermoplastic elastomer composition is crosslinked means that the degree of crosslinking measured by the following method is preferably 20% by weight or more, more preferably 45% by weight or more, particularly preferably 70% by weight or more We say that there is a case.
[Method of measuring crosslinking degree]
A 300 mg sample of the thermoplastic elastomer composition was collected, sealed in a 1000 mesh stainless steel wire mesh, and subjected to Soxhlet extraction for 8 hours at the boiling point of xylene using a xylene solvent. The sample was taken out and dried under reduced pressure in a vacuum oven at 40 ° C. for 24 hours or more until constant weight.
The value obtained by subtracting the weight of all the xylene insoluble components (fibrous filler, filler, pigment, etc.) other than stainless steel wire mesh and ethylene / α-olefin copolymer (B) component from the weight of this dry residue is Final weight (乙).
On the other hand, when the weight of the ethylene / α-olefin copolymer (B) in the sample or the soft resin (D) is used in combination, the total of the ethylene / α-olefin copolymer (B) and the soft resin (D) Let weight be "corrected initial weight (A)". Here, the degree of crosslinking is determined by the following equation.
Degree of crosslinking [%] = [corrected final weight (乙) / corrected initial weight (A)] × 100

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. In addition, the evaluation method and resin which were used by the Example and the comparative example are as follows.
1. Evaluation method of resin physical properties

(1) Melt flow rate (MFR): As described above, MFR of ethylene / α-olefin copolymer was measured in accordance with JIS-K6922-2: 1997 Annex (190 ° C., 21.18 N load) .
(2) Density: As described above, the density of the ethylene / α-olefin copolymer was measured in accordance with JIS-K6922-2: 1997 Appendix (23 ° C., in the case of low density polyethylene).
(3) Number of Branches and Number of Double Bonds: The number of branches (N) in the polymer is determined by ¹³ C-NMR as follows:
The numbers of vinyl and vinylidene (V) and internal vinylidene were measured by ¹ H-NMR under the following conditions, and the amount of comonomer was determined by the number per total of 1000 carbons of the main chain and side chains.

Device: Bruker Biospin KK AVANCE III Cryo-400 MHz
Solvent: o-Dichlorobenzene / Heavy Bromobenzene = 8/2 mixed solution <Sample amount>
460 mg / 2.3 ml
< ¹³ C-NMR>
・¹ H decoupling, NOE available ・ Number of integration: 256 scan
・ Flip angle: 90 °
・ Pulse interval 20 seconds ・ AQ (take-in time) = 5.45 s D1 (waiting time) = 14.55 s
< ¹ H-NMR>
・ Number of times of accumulation: 1400 scan
・ Flip angle: 1.03 °
・ AQ (intake time) = 1.8 s D1 (waiting time) = 0.01 s

2. Evaluation method of composition (1) Melt flow rate (MFR)
The MFR of the obtained composition was measured at 230 ° C. under a 10 kg load in accordance with JIS-K7210.

(2) Degree of Crosslinking A 300 mg sample of the thermoplastic elastomer composition was collected, sealed in a 1000 mesh stainless steel wire mesh, and subjected to Soxhlet extraction for 8 hours at the boiling point of xylene using a xylene solvent. The sample was taken out and dried under reduced pressure in a vacuum oven at 40 ° C. for 24 hours or more until constant weight.
The value obtained by subtracting the weight of all the xylene insoluble components (fibrous filler, filler, pigment, etc.) other than stainless steel wire mesh and ethylene / α-olefin copolymer (B) component from the weight of this dry residue is Final weight (乙).
On the other hand, when the weight of the ethylene / α-olefin copolymer (B) in the sample or the soft resin (D) is used in combination, the total of the ethylene / α-olefin copolymer (B) and the soft resin (D) Let weight be "corrected initial weight (A)". Here, the degree of crosslinking is determined by the following equation.
Degree of crosslinking [%] = [corrected final weight (乙) / corrected initial weight (A)] × 100

(3) Tensile strength and elongation The tensile strength at break and the breaking elongation at break were measured at a tensile speed of 200 mm / min according to JIS K 6301.

(4) Compression set The compression set was measured at a test temperature of 23 ° C. and 70 ° C. for a test time of 24 hours in accordance with JIS K 6262. (5) Shore A hardness A value after 15 seconds according to JIS K 6253 It was measured.

3. Raw materials used (1) Component (A) Polypropylene-based resin The following commercially available polypropylene resins (PP-1 and PP-2) were used. Physical properties are shown in Table 1.
(PP-1): PS 201A (homopolypropylene MFR = 0.5) manufactured by Sun Aroma Co., Ltd.
(PP-2): PM 900A (homopolypropylene MFR = 30) manufactured by Sun Aroma Co., Ltd.

(2) Component (B): Ethylene-alpha-olefin copolymer The ethylene-alpha-olefin copolymer (PE-1-PE-2) manufactured by the following manufacturing method was used as an example. Physical properties are shown in Table 1.

<Method of Manufacturing PE-1 to PE-2>
(I) Preparation of catalyst 0.05 mol of the complex “rac-dimethylsilylene bisindenyl hafnium dimethyl” prepared by the method described in JP-A-10-218921, and equimolar “N, N-dimethylanilinium tetrakis” (Pentafluorophenyl) borate "was added and diluted to 50 liters with toluene to prepare a catalyst solution.
(Ii) Polymerization method of PE-1 to -2 The pressure in the reactor was maintained at 80 MPa using a stirring autoclave type continuous reactor with an inner volume of 5.0 liters, and ethylene (C2), propylene (C3), 1- The source gas was continuously supplied at a predetermined rate of 40 kg / hour of hexene (C6). Further, the catalyst solution described in (i) Preparation of catalyst was continuously supplied, and the supply amount was adjusted so as to maintain the polymerization temperature described in Table 1. After completion of the reaction, MFR, density, vinyl content, vinylidene content, internal vinylidene content, number of branches, comonomer composition ratio of the ethylene / α-olefin copolymer obtained in Table 1 shown in Table 1 Copolymers (PE-1 to 2) were obtained.

On the other hand, as a comparative example, the following commercially available ethylene / α-olefin copolymer was used as PE-3. Physical properties are shown in Table 1.
(PE-3): Dow's Engage 8200

(3) Softener (C)
Using the following process oil commercially available (C-1): Process oil PW380 manufactured by Idemitsu Kosan Co., Ltd.

(4) Other (D)
The following commercially available EPDM was used as a soft resin.
(D-1): EPDM EP57C manufactured by JSR

(5) Crosslinking agent A commercially available organic peroxide described below was used as a crosslinking agent.
Crosslinking agent 1: 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane (Alkema Yoshitomi, Luperox 101)

(6) Crosslinking auxiliary:
The following commercially available substances were used as a crosslinking aid.
Crosslinking auxiliary 1: Triallyl cyanurate

Example 1
15 parts by weight of the polypropylene resin PP-1, 10 parts by weight of PP-2, and 55 parts by weight of the ethylene / α-olefin copolymer PE-1 with 0.5 parts by weight of the crosslinking agent 1 1.5 parts by weight of agent 1 was thoroughly mixed. This is fed from the feeder into the twin screw extruder hopper at a discharge rate of 8 kg / h, and at the same time the soft material C-1 is discharged by 2 kg / h (equivalent to 20% by weight of the whole composition) It injected into a shaft extruder feed part. The mixture was kneaded by using a 35 mmφ twin screw extruder at a set temperature of 160 ° C. and a screw rotation speed of 300 rpm under the conditions of an extrusion amount of 10 kg / h to pelletize. The extruded resin temperature at this time was 255 ° C.
Physical properties, such as mechanical strength, were measured and evaluated using the obtained pellet. The evaluation results are shown in Table 2.
(Example 2)
Pellets were produced in the same manner as in Example 1 except that PE-2 was used instead of PE-1 in Example 1. The extruded resin temperature at this time was 256 ° C. The evaluation results are shown in Table 2.
(Example 3)
Pellets were produced in the same manner as in Example 1 except that the compounding amount of PE-1 was 35 parts by weight and 20 parts by weight of the soft resin D-1 were used in Example 1. The extruded resin temperature at this time was 254 ° C. The evaluation results are shown in Table 2.
(Example 4)
Pellets were produced in the same manner as in Example 3 except that PE-2 was used instead of PE-1 in Example 3. The extruded resin temperature at this time was 255 ° C. The evaluation results are shown in Table 2.
(Comparative example 1)
Pellets were produced in the same manner as in Example 1 except that PE-3 was used instead of PE-1 in Example 1. The extruded resin temperature at this time was 240 ° C. The evaluation results are shown in Table 2.
(Comparative example 2)
Pellets were produced in the same manner as in Example 3 except that PE-3 was used instead of PE-1 in Example 3. The extruded resin temperature at this time was 244 ° C. The evaluation results are shown in Table 2.

（評価）
この結果、表２から明らかなように、ＰＥ−１、ＰＥ−２を用いたオレフィン系熱可塑性エラストマー組成物は、同一押出条件下でＰＥ−３を用いたものより架橋度が勝り、ゴム的弾性は同等で、機械的強度において、実施例１〜４は比較例１〜２よりも高い値を示している。よって、実施例は比較例のものと比較して、架橋特性が良くかつより高い機械的強度を有していることがわかる。

(Evaluation)
As a result, as is clear from Table 2, the olefin thermoplastic elastomer composition using PE-1 and PE-2 has a better degree of crosslinking and is rubbery than those using PE-3 under the same extrusion conditions The elasticity is equal, and in mechanical strength, Examples 1 to 4 show higher values than Comparative Examples 1 and 2. Thus, it can be seen that the examples have better crosslinking properties and higher mechanical strength than those of the comparative examples.

  The olefin-based thermoplastic elastomer composition of the present invention has good crosslinking properties and high mechanical strength, so for example, automobile parts (weather strip, hose, air bag cover, etc.), window frames, molds, cables, packing, various extrusions Industrial parts such as products can be widely applied.

Claims (7)

A polypropylene-based resin (A) and an ethylene / α-olefin copolymer (B) which is a copolymer consisting of ethylene and one or two or more kinds of α-olefins of 3 to 20 carbon atoms, And 10 parts by weight or more and 60 parts by weight or less of (A) and 40 parts by weight or more and 90 parts by weight or less of (B) with respect to 100 parts by weight of the total amount of
An olefin-based thermoplastic elastomer composition characterized in that the ethylene / α-olefin copolymer (B) has the following characteristics (b1) and (b2).
(B1) Density is 0.860 to 0.920 g / cm ³ (b2) Branch number (N) by comonomer in ethylene / α-olefin copolymer, total number of vinyl and vinylidene (V) is as follows The relationship of the formula (1) is satisfied, and the numbers of vinyl and vinylidene are each 0.05 or more.
Formula (1): N × V ≧ 15
(However, N and V are the number per total of 1000 carbons of the main chain and side chains measured by NMR.) The olefin-based thermoplastic elastomer composition according to claim 1, wherein the ethylene / α-olefin copolymer (B) further satisfies the following (b3).
(B3) The total number of vinyl and vinylidene double bonds in the ethylene / α-olefin copolymer is the total number of total double bonds (vinyl, vinylidene, cis-vinylene, trans-vinylene, trisubstituted olefin) 55% or more (However, the number of vinyl, vinylidene, cis-vinylene, trans-vinylene and trisubstituted olefin is the number per total of 1000 carbon atoms of the main chain and side chains measured by NMR) In the ethylene / α-olefin copolymer (B), the total number of vinyl and vinylidene in the (b4) ethylene / α-olefin copolymer, as determined by NMR, is a total of 1000 carbon atoms in the main chain and side chains. The olefin-based thermoplastic elastomer composition according to claim 1 or 2, wherein the number is 0.2 or more.   The olefin-based thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the ethylene / α-olefin copolymer (B) is produced by using a metallocene catalyst.   The olefin-based thermoplastic elastomer according to any one of claims 1 to 4, wherein the ethylene / α-olefin copolymer (B) contains 10 to 30 mol% of propylene as at least one component of α-olefin. Composition.   The softener (C) is contained in an amount of 2 to 100 parts by weight based on 100 parts by weight of the total amount of the polypropylene resin (A) and the ethylene / α-olefin copolymer (B). The olefin thermoplastic elastomer composition according to any one of claims 1 to 5.   The olefin-based thermoplastic elastomer composition according to any one of claims 1 to 6, wherein the olefin-based thermoplastic elastomer composition is crosslinked.