JP2013159632A - Thermoplastic elastomer composition and foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a thermoplastic elastomer composition superior to an ethylene-vinyl acetate copolymer in flexibility, molding processability, and fracture behavior such as tear strength; and a foam prepared by foaming the thermoplastic elastomer composition.SOLUTION: A thermoplastic elastomer composition includes an ethylene-vinyl acetate copolymer (X) and a copolymer (Y) of a conjugated diene compound and a nonconjugated olefin.

Description

  The present invention relates to a thermoplastic elastomer composition excellent in moldability and flexibility including an ethylene vinyl acetate copolymer, and a foam obtained by foaming this thermoplastic elastomer composition.

Ethylene vinyl acetate copolymers are widely used for materials that require flexibility, such as shock absorbers for shoes, and the ethylene vinyl acetate copolymers used for such applications are acetic acid in the copolymer. By adjusting the amount of vinyl, flexibility is improved.
However, when the amount of vinyl acetate in the ethylene vinyl acetate copolymer is increased, the glass transition temperature (Tg) is increased, so that the moldability is lowered.
Therefore, efforts to improve flexibility while maintaining moldability of the ethylene vinyl acetate copolymer, that is, research on resin compositions having both moldability and flexibility have been actively conducted. For example, the said subject is solved by mixing an ethylene vinyl acetate copolymer and other resin (refer patent document 1, 2).

JP 2002-80651 A JP 2000-14403 A

Even in the resin composition containing the ethylene-vinyl acetate copolymer described in Patent Documents 1 and 2, it is possible to obtain certain flexibility and moldability, but further improvement is desired. .
The present invention relates to a thermoplastic elastomer composition that is superior in flexibility and molding processability to an ethylene vinyl acetate copolymer and has excellent fracture behavior such as tear strength, and a foam formed by foaming this thermoplastic elastomer composition. The purpose is to provide a body.

The present inventor has found that the problems of the present invention can be solved by blending a specific copolymer with an ethylene vinyl acetate copolymer, and has completed the present invention.
That is, the present invention is a thermoplastic elastomer composition containing an ethylene vinyl acetate copolymer (X) and a copolymer (Y) of a conjugated diene compound and a non-conjugated olefin, and a foam obtained by foaming the same.

  According to the present invention, a thermoplastic elastomer composition that is superior in flexibility and molding processability to an ethylene vinyl acetate copolymer and excellent in fracture behavior such as tear strength, and the thermoplastic elastomer composition are foamed. A foam can be provided.

The thermoplastic elastomer composition according to the present invention comprises an ethylene vinyl acetate copolymer (X) and a copolymer (Y) of a conjugated diene compound and a non-conjugated olefin.
Thus, by blending the copolymer of the specific compound with the ethylene vinyl acetate copolymer (X), fracture behavior such as tear strength can be improved. The reason why the tear strength is improved when the copolymer is blended with the ethylene vinyl acetate copolymer (X) is that the rubber phase in which the copolymer is contained is deformed and the tear input from the outside is applied. This is probably because energy is consumed.

<Ethylene vinyl acetate copolymer (X)>
The ethylene vinyl acetate copolymer (X) used in the present invention includes ethylene and vinyl acetate by a production method such as solution polymerization, emulsion polymerization, and suspension polymerization, and a vinyl monomer copolymerizable with these, if necessary. If it is obtained by copolymerizing, there is no particular limitation.

  Examples of vinyl monomers that can be used include (meth) acrylic monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Styrene monomers such as styrene and α-methylstyrene, nitrile monomers such as acrylonitrile and methacrylonitrile, α-olefins and the like.

  As vinyl acetate content of the said ethylene vinyl acetate copolymer (X), 1-50 mass% is preferable, an upper limit is more preferable 35 mass% or less, and 25 mass% or less is still more preferable. When the content of vinyl acetate is within this range, the flexibility of the thermoplastic elastomer composition is further improved.

The Mooney viscosity is preferably 10 to 70 ML (1 + 4) 100 ° C. [conforms to JIS K6300]. If the Mooney viscosity is in this range, the workability and mechanical strength are more excellent.
In this invention, 1 type of the said ethylene vinyl acetate copolymer (X) may be used independently, and 2 or more types may be used together.

The weight average molecular weight (Mw) of the ethylene-vinyl acetate copolymer (X) is preferably 30,000 or more, more preferably 50,000 or more, and more preferably 100,000 or more from the viewpoint of improving fracture behavior without impairing workability. preferable.
Further, the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is preferably 10 or less, and more preferably 6 or less. When the molecular weight distribution is 10 or less and the molecular weight distribution is narrow, the physical properties are uniform.
In addition, a weight average molecular weight, a number average molecular weight, and molecular weight distribution can obtain | require polystyrene as a standard substance by the gel permeation chromatography (GPC) measured on appropriate temperature conditions.

The solubility parameter δ (SP value) of the ethylene vinyl acetate copolymer (X) is more preferably in the range of 5 to 12 (cal · cc ⁻¹ ) ^1/2 . When the solubility parameter δ (SP value) of the ethylene vinyl acetate copolymer (X) is in this range, the phase with the copolymer (Y) (a copolymer of a conjugated diene compound and a nonconjugated olefin) is obtained. The solubility becomes good, and the impact resistance and fracture characteristics of the resin composition can be improved.

The solubility parameter δ (cal · cc ⁻¹ ) ^1/2 is defined by the following formula (1) in consideration of the attractive force between molecules in the Hildebrand-Scatchard solution theory.
δ = (ΔE _V / V ₁ ) ^1/2 (1)
Here, ΔE _V represents evaporation energy, V ₁ represents molecular volume, and ΔE _V / V ₁ represents cohesive energy density (CED).
The solubility parameter δ (SP value) in the present invention is a value calculated according to the Fedors method.

<Copolymer of conjugated diene compound and non-conjugated olefin (Y)>
Next, the copolymer (Y) of a conjugated diene compound and a non-conjugated olefin will be described.
≪Configuration of copolymer (Y) of conjugated diene compound and non-conjugated olefin≫
The cis-1,4-bond amount of the conjugated diene compound-derived portion (conjugated diene portion) of the copolymer (Y) of the conjugated diene compound and non-conjugated olefin used in the present invention is preferably 50% or more, More preferably, it exceeds 92%, and more preferably 95% or more. If the amount of cis-1,4 bonds in the conjugated diene compound portion (part derived from the conjugated diene compound) is 50% or more, a low glass transition point (Tg) can be maintained, and thereby, impact resistance at low temperatures can be maintained. Improved.

By making the cis-1,4-bond amount of the conjugated diene compound-derived moiety (conjugated diene moiety) more than 92%, the tear strength, impact resistance at low temperature, crack growth resistance, weather resistance, and heat resistance are improved. It becomes possible. Further, when the cis-1,4-bond amount of the conjugated diene compound-derived portion (conjugated diene portion) is 95% or more, the tear strength, impact resistance at low temperature, crack growth resistance, weather resistance, and heat resistance are further improved. be able to.
The amount of cis-1,4 bonds is the amount in the conjugated diene compound-derived moiety, and is not a ratio relative to the entire copolymer.

  10-70 mol% is preferable and, as for the ratio of the nonconjugated olefin origin part in the copolymer of a conjugated diene compound and a nonconjugated olefin, 20-70 mol% is more preferable. Within this range, the tear strength is good and the impact resistance is good. From this viewpoint, the proportion of the non-conjugated olefin-derived portion in the copolymer is more preferably 20 to 50 mol%, and further preferably 20 to 35 mol%.

  The non-conjugated olefin is preferably an acyclic olefin. Moreover, it is preferable that carbon number of a nonconjugated olefin is a 2-10 alpha olefin. Since the α-olefin has a double bond at the α-position of the olefin, it can be efficiently copolymerized with the conjugated diene compound. Accordingly, preferred examples of non-conjugated olefins include α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and among these, ethylene, propylene and 1-butene is preferred and ethylene is more preferred. These non-conjugated olefins may be used alone or in combination of two or more. In addition, an olefin refers to the compound which is an aliphatic unsaturated hydrocarbon and has one or more carbon-carbon double bonds.

The conjugated diene compound preferably has 4 to 12 carbon atoms. Specific examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, and among these, 1,3-butadiene and isoprene are preferable. Moreover, these conjugated diene compounds may be used independently and may be used in combination of 2 or more type.
The copolymer can be prepared by the same mechanism using any of the specific examples of the conjugated diene compound described above.

  The copolymer of the conjugated diene compound and the non-conjugated olefin does not cause a problem of lowering the molecular weight, and the weight average molecular weight (Mw) is not particularly limited. From the viewpoint of application to a polymer structural material, the polystyrene-converted weight average molecular weight (Mw) of the copolymer of the conjugated diene compound and the nonconjugated olefin is preferably 10,000 to 10,000,000. 1,000,000 is more preferable, and 50,000-600,000 is still more preferable. If the Mw is 10,000,000 or less, the moldability becomes good.

  The copolymer according to the present invention preferably has a conjugated diene compound-derived portion having a 1,2-adduct portion (including 3,4-adduct portion) content of 5% or less in the conjugated diene compound-derived portion. More preferably, it is 3% or less, More preferably, it is 2.5% or less.

  When the content of the 1,2-adduct portion (including the 3,4-adduct portion) of the conjugated diene compound in the conjugated diene compound-derived portion is 5% or less, the weather resistance and ozone resistance of the copolymer according to the present invention are improved. Further improvement can be achieved. Furthermore, when the content of 1,2 adducts (including 3,4 adducts) in the conjugated diene compound portion is 2.5% or less, the copolymer of the present invention further improves ozone resistance and fatigue resistance. Can be improved.

The content of the 1,2-adduct portion (including the 3,4-adduct portion) of the conjugated diene compound in the conjugated diene compound-derived portion is an amount in the conjugated diene compound-derived portion, and is not a ratio to the entire copolymer.
The 1,2-adduct portion (including 3,4-adduct portion) content of the conjugated diene compound portion (including the 3,4-adduct portion) Including) content) has the same meaning as the amount of 1,2-vinyl bonds when the conjugated diene compound is butadiene.

Further, the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is preferably 10 or less, and more preferably 6 or less. If the molecular weight distribution is 10 or less, the physical properties are uniform.
Here, the average molecular weight and the molecular weight distribution can be determined using polystyrene as a standard substance by gel permeation chromatography (GPC).

The copolymer of the conjugated diene compound and the non-conjugated olefin according to the present invention may be a random copolymer or a block copolymer. Alternatively, a taper copolymer may be used. The taper copolymer is a copolymer in which a random copolymer and a block copolymer are mixed, from a block portion composed of monomer units of a conjugated diene compound and a monomer unit of non-conjugated olefins. And at least one block portion (also referred to as a block structure) and a random portion (also referred to as a random structure) in which monomer units of a conjugated diene compound and a non-conjugated olefin are irregularly arranged. It is a copolymer.
That is, the taper copolymer indicates that the composition of the conjugated diene compound component and the non-conjugated olefin component is distributed continuously or discontinuously.
Alternatively, it may be an alternating copolymer in which conjugated diene compounds and non-conjugated olefins are alternately arranged (a molecular chain structure of -ABABABAB-, where A is a conjugated diene compound and B is a non-conjugated olefin). .

The structure of the block copolymer is (AB) _x , A- (BA) _x and B- (AB) _x (where A is a block composed of monomer units of a conjugated diene compound). And B is a block portion composed of monomer units of non-conjugated olefin, and x is an integer of 1 or more. In addition, the block copolymer provided with two or more structures of (AB) or (BA) is called a multiblock copolymer.
In the case of the block copolymer, the block portion composed of the monomer unit of the non-conjugated olefin exhibits static crystallinity, and thus is excellent in mechanical properties such as breaking strength and gas barrier properties.

When the copolymer (Y) of a conjugated diene compound and a non-conjugated olefin is a random copolymer, the arrangement of the monomer units of the non-conjugated olefin is irregular, and the copolymer causes phase separation. There is no crystallization temperature derived from the block portion. That is, the heat resistance of the copolymer is improved. This makes it possible to introduce a non-conjugated olefin having properties such as heat resistance into the main chain of the copolymer.
Content of the said copolymer (Y) (copolymer of a conjugated diene compound and a nonconjugated olefin) is 1-110 mass parts with respect to 100 mass parts of the above-mentioned ethylene vinyl acetate copolymers (X). It is preferable that it is 1 to 100 parts by mass. By setting it within this range, flexibility and fracture behavior can be improved while suppressing a decrease in molding processability. From this viewpoint, the content of the copolymer is more preferably 30 to 100 parts by mass, further preferably 50 to 100 parts by mass, and still more preferably 70 to 100 parts by mass.

≪Method for producing copolymer (Y) of conjugated diene compound and non-conjugated olefin≫
Next, the manufacturing method of a copolymer is demonstrated in detail. However, the manufacturing method described in detail below is merely an example. The copolymer according to the present invention can be produced by polymerizing a conjugated diene compound and a non-conjugated olefin in the presence of a polymerization catalyst or a polymerization catalyst composition.

  As a polymerization method, any method such as a solution polymerization method, a suspension polymerization method, a liquid phase bulk polymerization method, an emulsion polymerization method, a gas phase polymerization method, and a solid phase polymerization method can be used. Moreover, when using a solvent for a polymerization reaction, the solvent used should just be inactive in a polymerization reaction, For example, toluene, cyclohexane, normal hexane, mixtures thereof etc. are mentioned.

The method for producing a copolymer (Y) of a conjugated diene compound and a non-conjugated olefin includes, for example, (1) a polymerization reaction system including a conjugated diene compound as a monomer and a non-conjugated olefin other than the conjugated diene compound. The components of the polymerization catalyst composition may be provided separately and used as a polymerization catalyst composition in the reaction system, or (2) a polymerization catalyst composition prepared in advance may be provided in the polymerization reaction system. Moreover, (2) includes providing a metallocene complex (active species) activated by a cocatalyst. In addition, the usage-amount of the metallocene complex contained in a polymerization catalyst composition has the preferable range of 0.0001-0.01 times mole with respect to the sum total of nonconjugated olefins other than a conjugated diene compound and this conjugated diene compound.
Moreover, in the manufacturing method of the copolymer of a conjugated diene compound and a nonconjugated olefin, you may stop superposition | polymerization using polymerization terminators, such as methanol, ethanol, and isopropanol.

  The polymerization reaction of the conjugated diene compound and the non-conjugated olefin is preferably performed in an atmosphere of an inert gas, preferably nitrogen gas or argon gas. The polymerization temperature of the polymerization reaction is not particularly limited, but is preferably in the range of −100 ° C. to 200 ° C., for example, and can be about room temperature. If the polymerization temperature is raised, the cis-1,4 selectivity of the polymerization reaction may be lowered. Moreover, since the pressure of the said polymerization reaction fully takes in a conjugated diene compound and a nonconjugated olefin in a polymerization reaction system, the range of 0.1-10.0 MPa is preferable. Further, the reaction time of the polymerization reaction is not particularly limited, and is preferably in the range of 1 second to 10 days, for example, but may be appropriately selected depending on conditions such as the type of monomer to be polymerized, the type of catalyst, and the polymerization temperature. it can.

  In the polymerization of the conjugated diene compound and a non-conjugated olefin other than the conjugated diene compound, the pressure of the non-conjugated olefin is preferably 0.1 MPa to 10 MPa. When the pressure of the non-conjugated olefin is 0.1 MPa or more, the non-conjugated olefin can be efficiently introduced into the reaction mixture. Moreover, even if the pressure of the non-conjugated olefin is increased too much, the effect of efficiently introducing the non-conjugated olefin reaches a peak, and therefore the pressure of the non-conjugated olefin is preferably 10 MPa or less.

  In the method for producing the copolymer, when the conjugated diene compound is polymerized with a non-conjugated olefin other than the conjugated diene compound, the concentration of the conjugated diene compound at the start of polymerization (mol / l) and the concentration of the non-conjugated olefin (Mol / l) preferably satisfies the relationship of the following formula. By setting the value of the concentration of the non-conjugated olefin / the concentration of the conjugated diene compound to 1 or more, the non-conjugated olefin can be efficiently introduced into the reaction mixture.

Non-conjugated olefin concentration / conjugated diene compound concentration ≧ 1.0
More preferably, it is preferable to satisfy | fill the relationship of a following formula.
Non-conjugated olefin concentration / conjugated diene compound concentration ≧ 1.3
More preferably, it is preferable to satisfy | fill the relationship of a following formula.
Non-conjugated olefin concentration / conjugated diene compound concentration ≧ 1.7

  According to the production method, except that the polymerization catalyst or the polymerization catalyst composition is used, the monomer conjugated diene compound and the non-conjugated compound are produced in the same manner as in the production method of the polymer by the normal coordination ion polymerization catalyst. Olefin can be copolymerized. In addition, the more specific manufacturing method of the copolymer of the said conjugated diene compound and nonconjugated olefin used by this invention is as having described in WO2011 / 016210, for example.

<Other ingredients>
-Filler The thermoplastic elastomer composition may contain a filler. As the filler, those generally used without particular limitation can be used as necessary.
Specific examples of inorganic fillers include silicates such as fine powder talc, kaolinite, calcined clay, biophyllite, sericite and wollastonite, carbonates such as precipitated calcium carbonate, heavy calcium carbonate and magnesium carbonate. , Hydroxides such as marine products aluminum, magnesium hydroxide, oxides such as zinc oxide, zinc white, magnesium oxide, powders of synthetic silicic acid or silicates such as hydrous calcium silicate, hydrous aluminum silicate, hydrous silicic acid, anhydrous silicic acid Flaky filler such as mica; fibrous filler such as basic magnesium sulfate whisker, calcium titanate whisker, aluminum borate whisker, sepiolite, PMF (Processed Mineral Fiber), zonotlite, potassium titanate, elestite ; Glass balun, fly ash balun, etc. Agent; and the like.

-Rubber component You may mix | blend another rubber component and another resin component with the thermoplastic-elastomer composition which concerns on this invention. Other rubber components are not particularly limited and may be appropriately selected depending on the purpose. For example, other conjugated diene compounds and copolymers of nonconjugated olefins, natural rubber, various butadiene rubbers, various styrene- Butadiene copolymer rubber, isoprene rubber, butyl rubber, bromide of copolymer of isobutylene and p-methylstyrene, halogenated butyl rubber, acrylonitrile butadiene rubber, chloroprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene Copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene copolymer rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluorine Rubber, urethane rubber And the like. These may be used individually by 1 type and may use 2 or more types together.

Additives The thermoplastic elastomer composition of the present invention includes softeners, nucleating agents, antioxidants, anti-aging agents, hydrochloric acid absorbents, heat stabilizers, light stabilizers, UV absorbers, lubricants, antistatic agents. Agent, flame retardant, pigment, dye, dispersant, copper damage inhibitor, neutralizer, foaming agent, plasticizer, anti-bubble agent, cross-linking agent, cross-linking aid, cross-linking accelerator, peroxide, etc. Additives such as an agent, a heweld strength improver, a plasticizer, a processing aid, a weathering stabilizer, an anti-coloring agent, and an anti-blooming agent may be included.
The crosslinking agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a sulfur-based crosslinking agent, an organic peroxide-based crosslinking agent, an inorganic crosslinking agent, a polyamine crosslinking agent, a resin crosslinking agent, and a sulfur compound. System crosslinking agent, oxime-nitrosamine system crosslinking agent sulfur and the like.

<Manufacture of thermoplastic elastomer composition>
The thermoplastic elastomer composition of the present invention is a mixture of the above-mentioned various components and melts an ethylene vinyl acetate copolymer (X) and a copolymer (Y) (a copolymer of a conjugated diene compound and a non-conjugated olefin). -It can be manufactured by kneading. From the viewpoint of sufficiently melting and kneading while saving time and energy, the melting and kneading temperature is preferably 100 to 250 ° C, more preferably 120 to 230 ° C.
This thermoplastic elastomer composition is suitably used for impact absorbing applications such as shoe soles.
Moreover, the molding method applied with respect to the conventional resin composition is applicable to this thermoplastic elastomer composition without a restriction | limiting in particular. As the molding method, a known molding method such as injection molding, extrusion molding, vacuum / compression molding or the like can be employed.
In the thermoplastic elastomer composition, a foam having high flexibility can be obtained by foaming the thermoplastic elastomer composition by a known method. Examples of the foaming method include a so-called decompression method in which a material containing a thermoplastic elastomer composition is supplied into a cavity formed in a mold and the material is foamed and molded while decompressing the inside of the cavity. Can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
The analysis method of ethylene-butadiene copolymer (EBR) and the evaluation method of thermoplastic elastomer are shown below.

<Analytical method of ethylene-butadiene copolymer (EBR (a) and EBR (b))>
・ Copolymer microstructure (1,2-vinyl bond content, cis-1,4 bond content)
The microstructure of the butadiene moiety in the copolymer (1,2-vinyl bond content) was determined from the 1,2-vinyl bond component (5.0 by ¹ H-NMR spectrum (100 ° C., d-tetrachloroethane standard: 6 ppm)). -5.1 ppm) and the integral ratio of the entire butadiene bond component (5-5.6 ppm). Further, the microstructure (cis-1,4 bond amount) of the butadiene moiety in the copolymer is determined based on the ¹³ C-NMR spectrum (100 ° C., d-tetrachloroethane standard: 73.8 ppm). (26.5-27.5 ppm) and the total butadiene bond component (26.5-27.5 ppm + 31.5-32.5 ppm) were obtained from the integral ratio.

-Ethylene content of copolymer The content (mol%) of the ethylene moiety in the copolymer is the total ethylene bond component (28 according to ¹³ C-NMR spectrum (100 ° C, d-tetrachloroethane standard: 73.8 ppm). .5-30.0 ppm) and the total butadiene bond component (26.5-27.5 ppm + 31.5-32.5 ppm).

-Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the copolymer
Gel permeation chromatography [GPC: Tosoh HLC-8121GPC / HT, column: Tosoh GMH _HR- H (S) HT × 2, detector: differential refractometer (RI)] on the basis of monodisperse polystyrene The polystyrene equivalent weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer were determined. The measurement temperature is 140 ° C.

-Block polyethylene melting point of copolymer (DSC peak temperature)
Differential scanning calorimetry (DSC) was performed according to JIS K7121-1987, a DSC curve was drawn, and a block polyethylene melting point (DSC peak temperature) was measured. In order to avoid the influence of impurities such as single polymer and catalyst residue, the measurement is performed by immersing the copolymer in a large amount of tetrahydrofuran for 48 hours, removing all components dissolved in tetrahydrofuran, and then using the dried rubber component as a sample. did.

-Identification of copolymer The chain distribution was analyzed by applying the ozonolysis-GPC method in the literature ("Proceedings of the Society of Polymer Science, Vol. 42, No. 4, Page 1347"). The gel permeation chromatography was measured based on [GPC: Tosoh HLC-8121GPC / HT, column: Showa Denko GPC HT-803 × 2, detector: differential refractometer (RI), monodisperse polystyrene as a reference. The temperature was measured using 140 ° C.].

<Evaluation method>
-Tear Strength The tear strength measurement is based on the conditions of ASTM-D624 at 170 ° C. The shape of the test piece was a ring shape with a notch (ASTM-624-C). The specimen was tested at a specific gauge length of 1.750 inches.
About Examples 1-4 and Comparative Examples 1-3, the value of the comparative example 1 was set to 100, and the index display was carried out by the following formula. The larger the value, the better the tear strength.
Tear strength index = {(Tear strength of test sample) / (Tear strength of sample of Comparative Example 1)
Degree)} × 100
About Examples 5-8 and Comparative Examples 4-6, the value of the comparative example 4 was set to 100, and the index display was carried out by the following formula. The larger the value, the better the tear strength.
Tear strength index = {(Tear strength of test sample) / (Tear strength of sample of Comparative Example 4)
Degree)} × 100

-Impact resistance It carried out with the Charpy impact tester according to JISK7111: 1996 at normal temperature (25 degreeC).
About Examples 1-4 and Comparative Examples 1-3, the value of the comparative example 1 was set to 100, and the index display was carried out by the following formula. The larger the value, the better the impact resistance.
Impact resistance index = {(impact value of test sample) / (impact value of sample of comparative example 1)} × 100
About Examples 5-8 and Comparative Examples 4-6, the value of the comparative example 4 was set to 100, and the index display was carried out by the following formula. The larger the value, the better the impact resistance.
Impact resistance index = {(Shock value of test sample) / (Shock value of sample of Comparative Example 4)} × 100

・ Melt flow rate (evaluation of processability)
A sample was filled in a cylinder with an inner diameter of 9.55 mm and a length of 162 mm of a melt indexer L244 (Takara Industry Co., Ltd.), melted at 190 ° C., and then a blanker with a weight of 2160 g and a diameter of 9.48 mm was used. Load evenly. The amount of resin extruded per unit time (g / 10 minutes) from an orifice with a diameter of 2.1 mm provided in the center of the cylinder was measured, and this was used as the melt flow rate. However, if the melting point of the sample is around 190 ° C or exceeds 190 ° C, the measurement is performed under a load of 2160g and at a plurality of temperatures above the melting point. And the value extrapolated to 190 ° C.
About Examples 1-4 and Comparative Examples 1-3, the value of the comparative example 1 was set to 100, and the index display was carried out by the following formula. The larger the value, the better the workability.
Flow rate index = {(flow rate of test sample) / (flow rate of sample of comparative example 1)
G)} × 100
About Examples 5-8 and Comparative Examples 4-6, the value of the comparative example 4 was set to 100, and the index display was carried out by the following formula. The larger the value, the better the workability.
Flow rate index = {(flow rate of test sample) / (flow rate of sample of Comparative Example 4)
G)} × 100

Production Example 1
(A) Production of block polymerization type of ethylene-butadiene copolymer (EBR) After 150 ml of toluene was added to a sufficiently dry 2 L stainless steel reactor, ethylene was introduced at 0.8 MPa. On the other hand, in a glove box under a nitrogen atmosphere, bis (2-phenylindenyl) gadolinium bis (dimethylsilylamide) [(2-PhC ₉ H ₆ ) ₂ GdN (SiHMe ₂ ) ₂ ] 14.5 μmol was placed in a glass container. , Triphenylcarbonium tetrakis (pentafluorophenyl) borate (Ph ₃ CB (C ₆ F ₅ ) ₄ ) 14.1 μmol and diisobutylaluminum hydride 0.87 mmol were charged and dissolved in 5 ml of toluene to obtain a catalyst solution. Thereafter, the catalyst solution was taken out from the glove box, an amount of 14.1 μmol in terms of gadolinium was added to the monomer solution, and polymerization was carried out at 50 ° C. for 5 minutes. Thereafter, 20 ml of a toluene solution containing 3.05 g (0.056 mol) of 1,3-butadiene was added while lowering the ethylene introduction pressure at a rate of 0.2 MPa / min, and polymerization was further performed for 15 minutes. Next, “the ethylene introduction pressure was returned to 0.8 MPa, polymerization was performed for 5 minutes, and then the ethylene introduction pressure was reduced at a rate of 0.2 MPa / min, while 6.09 g (0. The operation of adding 40 ml of a toluene solution containing 113 mol) and then performing polymerization for another 30 minutes was repeated a total of 3 times. After the polymerization, 1 ml of 2,2′-methylene-bis (4-ethyl-6-t-butylphenol) (NS-5) 5% by mass isopropanol solution was added to stop the reaction, and the copolymer was separated with a large amount of methanol. And vacuum-dried at 70 ° C. to obtain a polymer. The yield of the obtained copolymer (a) was 24.50 g.
For the obtained copolymer (a), the microstructure, ethylene content, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), block polyethylene melting point (DSC peak temperature) and chain structure were measured by the above methods. ·evaluated.
As the microstructure of the butadiene portion in the copolymer (a), the cis-1,4-bond amount was 97% and the 1,2-vinyl bond amount was 1.4%.
The weight average molecular weight Mw was 205,000, and the molecular weight distribution Mw / Mn was 9.15.
The ethylene content was 34 mol%.
The block polyethylene melting point (DSC peak temperature) was 121 ° C., and the chain structure was a block.

Production Example 2
(B) Production of random polymerization type of ethylene-butadiene copolymer (EBR) After adding 700 ml of a toluene solution containing 28.0 g (0.52 mol) of 1,3-butadiene to a sufficiently dry 2 L stainless steel reactor Ethylene was introduced at 0.8 MPa. On the other hand, dimethylaluminum (μ-dimethyl) bis (2-phenylindenyl) neodymium [(2-PhC ₉ H ₆ ) ₂ Nd (μ-Me) ₂ AlMe _{2 is} placed in a glass container in a glove box under a nitrogen atmosphere. 400.0 μmol and 200.0 μmol of triphenylcarbonium tetrakis (pentafluorophenyl) borate (Ph ₃ CB (C ₆ F ₅ ) ₄ ) were charged and dissolved in 80 ml of toluene to obtain a catalyst solution. Thereafter, the catalyst solution was taken out from the glove box, an amount of 390.0 μmol in terms of neodymium was added to the monomer solution, and polymerization was performed at room temperature for 120 minutes. After the polymerization, 1 ml of 2,2′-methylene-bis (4-ethyl-6-tert-butylphenol) (NS-5) 5% by mass of isopropanol solution was added to stop the reaction, and a copolymer with a large amount of methanol was added. Was separated and vacuum dried at 70 ° C. to obtain a copolymer (b). The yield of the obtained copolymer (b) was 18.00 g.
About the obtained copolymer (b), the microstructure, ethylene content rate, the weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) were measured and evaluated by said method.
As the microstructure of the butadiene portion in the copolymer (b), the cis-1,4-bond amount was 91% and the 1,2-vinyl bond amount was 2.1%.
The weight average molecular weight Mw was 263,000, and the molecular weight distribution Mw / Mn was 1.58. The ethylene content was 15 mol%.
Since the chain structure of the ethylene-butadiene copolymer (b) (EBR) is random, the ethylene portion of the copolymer (b) having a random structure is taken out, and the taken-out ethylene portion is taken into this copolymer (b The melting temperature of the hypothetical polymer obtained by homopolymerization under the same conditions as in the synthesis of ()) was taken as the melting temperature of the ethylene portion of the random copolymer.
The melting temperature of the ethylene part of the copolymer (b) was 110 ° C.

<Examples 1-4 and Comparative Examples 1-3>
According to the blending contents shown in Table 1, a thermoplastic elastomer composition was prepared by kneading at 200 ° C. and 150 rpm using a twin screw extruder and pelletizing with a pelletizer.
Next, the test piece was shape | molded at 200 degreeC using the injection molding machine from the obtained pellet of the Example and the comparative example. Using each of the obtained test pieces, impact resistance, tear strength and melt flow rate were evaluated by the above methods. The results are shown in Table 1.

In addition, the following were used as a component shown in Tables 1 and 2.
EVA: ethylene vinyl acetate copolymer (X)
Tosoh Corporation
Product name "UE634",
Vinyl acetate content 26% by mass
Mw120000, Mn31000, Mw / Mn3.9
・ PE: Polyethylene resin, Prime Polymer Co., Ltd.
Product name "HI-ZEX (HDPE) 1608J"

  As is clear from Table 1, Examples 1-4 were found to have better tear strength, impact resistance, and melt flow rate than Comparative Examples 1-3.

<Examples 5-8 and Comparative Examples 4-6>
According to the blending contents shown in Table 2, a thermoplastic elastomer composition was prepared by kneading at 200 ° C. and 150 rpm using a twin screw extruder and pelletizing with a pelletizer.
Next, the test piece was shape | molded at 200 degreeC using the injection molding machine from the obtained pellet of the Example and the comparative example. Using each of the obtained test pieces, impact resistance, tear strength and melt flow rate were evaluated by the above methods. The results are shown in Table 2.

  As is clear from Table 2, Examples 5 to 8 were found to have better tear strength, impact resistance, and melt flow rate than Comparative Examples 4 to 6.

Claims (14)

An ethylene vinyl acetate copolymer (X);
A thermoplastic elastomer composition comprising a conjugated diene compound and a copolymer (Y) of a non-conjugated olefin.   The thermoplastic elastomer composition according to claim 1, wherein the content of the copolymer (Y) is 1 to 100 parts by mass with respect to 100 parts by mass of the ethylene vinyl acetate copolymer (X).   The thermoplastic elastomer composition according to claim 1 or 2, wherein the content of vinyl acetate in the ethylene vinyl acetate copolymer (X) is 1 to 50 mass%.   The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein an amount of cis-1,4 bonds in the conjugated diene compound portion of the copolymer (Y) is 50% or more.   The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein in the copolymer, the proportion of the non-conjugated olefin-derived portion is 20 to 70 mol%.   The thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the copolymer (Y) is a block copolymer.   The thermoplastic elastomer composition according to any one of claims 1 to 6, wherein the copolymer (Y) has a weight average molecular weight in terms of polystyrene of 10,000 to 10,000,000.   The thermoplastic elastomer composition according to any one of claims 1 to 7, wherein the copolymer (Y) has a molecular weight distribution (Mw / Mn) of 10 or less.   The thermoplastic elastomer composition according to any one of claims 1 to 8, wherein the non-conjugated olefin is an acyclic olefin.   The thermoplastic elastomer composition according to any one of claims 1 to 9, wherein the non-conjugated olefin has 2 to 10 carbon atoms.   The thermoplastic elastomer composition according to claim 9, wherein the non-conjugated olefin is at least one selected from the group consisting of ethylene, propylene, and 1-butene.   The thermoplastic elastomer composition according to claim 11, wherein the non-conjugated olefin is ethylene.   The thermoplastic elastomer composition according to any one of claims 1 to 12, wherein the conjugated diene compound is at least one selected from the group consisting of 1,3-butadiene and isoprene.   A foam formed by foaming the thermoplastic elastomer composition according to any one of claims 1 to 13.