JP6911344B2 - Thermoplastic elastomer resin composition - Google Patents

Description

The present invention relates to a thermoplastic elastomer having excellent heat resistance and deformation recovery. Specifically, the present invention has heat resistance capable of maintaining its shape even under a temperature condition of 45 ° C. or higher, and is continuously deformed by a continuous load. After that, the present invention relates to a thermoplastic elastomer resin composition having deformation recovery property when the load is removed.

In recent years, thermoplastic elastomer materials, which are soft materials having rubber elasticity and which do not require a vulcanization process and can be molded and recycled in the same manner as thermoplastic resins, have been used for bedding such as pillows and mattresses, automobile parts, and home appliances. It is widely used in the fields of parts, wire coating, medical parts, miscellaneous goods, bedding, etc. Among such thermoplastic elastomer materials, olefin-based thermoplastic elastomers made of polyolefin-based resins are widely used because they are excellent in deformation recovery.

Ethylene / α-olefin copolymers can be extruded and have excellent rubber elasticity and deformation recovery, so they are durable in applications that are relatively repeatedly compressed, such as cushioning materials, cushions and mats. Useful for improving. In general, an ethylene / α-olefin copolymer is a useful elastomer having better deformation recovery and flexibility as the density is lower, but it is difficult to achieve both heat resistance and deformation recovery.

In order to solve this problem, for example, in Patent Document 1, a specific ethylenically unsaturated silane compound is grafted onto a specific ethylene-based copolymer. However, it takes a long time of one week in a room where hot water is sprayed in the form of mist, which is inferior in productivity, and because it is crosslinked, it is excellent in deformation recovery and heat resistance, but it is recyclable. It was inferior to.

Japanese Unexamined Patent Publication No. 2013-181117

The present invention relates to a thermoplastic elastomer resin composition having excellent heat resistance and deformation recovery. Specifically, the present invention has heat resistance capable of maintaining a shape even under a temperature condition of 45 ° C. or higher, and continuously under a continuous load. It is an object of the present invention to provide a thermoplastic elastomer resin composition having deformation recovery property when a load is removed after being deformed.

As a result of diligent research to solve the above problems, the present invention has been completed. That is, the present invention has a density of 30 to 95 parts by weight of the ethylene / α-olefin copolymer (A) ^{having a density of 900 to 920 kg / m 3 and a weight average molecular weight measured by GPC in the range of 40,000 to 100,000.} Ethylene / α-olefin copolymer (B) 5 to 70 parts by weight ((A) and (B)) having a weight average molecular weight of 890 to 920 kg / m ^{3 and a weight average molecular weight in the range of 110,000 to 250,000 measured by GPC.} The total is 100 parts by weight), and the present invention relates to a thermoplastic elastomer resin composition having a hysteresis loss rate of 30% or less at 23 ° C. and a deformation recovery rate of 70% or more at 45 ° C. ..

The thermoplastic elastomer composition of the present invention has excellent strain recovery properties, and has excellent strain recovery properties, such as office chairs, furniture, sofas, bed pads, mattresses, vehicle seats such as trains, automobiles, motorcycles, strollers, and child seats, floor mats, and collisions. It has become possible to provide a resin suitable for a cushion material used for a mat for shock absorption such as a pinch prevention member or the like. In particular, it has become possible to provide a resin composition suitable for cushioning materials such as office chairs, furniture, sofas, bed pads, and mattresses, which are prone to settling due to temperature due to summer or body temperature.

Hereinafter, the present invention will be described in detail.

The thermoplastic elastomer resin composition of the present invention contains two types of ethylene / α-olefin copolymer resins having different densities. The ethylene / α-olefin copolymer of the present invention is obtained by copolymerizing ethylene with an α-olefin having 3 or more carbon atoms. Here, examples of the α-olefin having 3 or more carbon atoms include propylene, butene-1, penten-1, hexene-1, 4-methyl-1-pentene, heptene-1, octene-1, nonene-1, and decene. -1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonenecene-1, eikocene-1, etc. -1, penten-1, hexene-1, 4-methyl-1-pentene, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1 , Pentadecene-1, Hexadecene-1, Heptene-1, Octadecene-1, Nonadesen-1, Eikosen-1. Further, two or more of these can be used, and these α-olefins are usually copolymerized in an amount of 1 to 40% by weight. This copolymer can be obtained by copolymerizing ethylene and α-olefin using a catalyst system based on a metallocene compound and an organometallic compound.

The density of the ethylene / α-olefin copolymer (A) is 900 to 920 kg / m ³ . It is preferably 915 kg / m ³ or less, more preferably 0.913 kg / m ³ or less. The lower limit of the density is from the viewpoint of heat resistance 900 kg / ^{m 3} or more, 901kg / ^{m 3} or more. If the density exceeds 920 kg / cm ³ , the hysteresis loss rate of the thermoplastic elastomer resin composition increases, which impairs the elastic properties, which is not preferable. When the density is ^{smaller than 900 kg / m 3} , the hysteresis loss becomes small, but it is not preferable because the heat resistance is impaired.

The density of the ethylene / α-olefin copolymer (B) is 890 to 920 kg / m ³ , preferably 915 kg / m ³ or less. If the density exceeds 920 kg / m ³ , the hysteresis loss rate of the thermoplastic elastomer resin composition increases, which impairs the elastic properties, which is not preferable. If the density is ^{less than 890 kg / m 3} , the heat resistance is impaired, which is not preferable.

The molecular weight of the ethylene / α-olefin copolymer (A) has a weight average molecular weight in the range of 40,000 to 100,000, preferably in the range of 40,000 to 90,000. If the weight average molecular weight exceeds 100,000, the moldability is significantly impaired, which is not preferable. If the weight average molecular weight is less than 40,000, the deformation recovery is impaired, which is not preferable.

The molecular weight of the ethylene / α-olefin copolymer (B) has a weight average molecular weight in the range of 110,000 to 250,000, preferably in the range of 110,000 to 200,000. If the weight average molecular weight exceeds 250,000, the moldability is significantly impaired, which is not preferable. If the weight average molecular weight is less than 100,000, the effect of improving the deformation recovery is small, which is not preferable.

The component ratio of the ethylene / α-olefin copolymer (A) is 30 to 95 parts by weight, preferably 30 to 90 parts by weight. When the component ratio of the ethylene / α-olefin copolymer (A) exceeds 95 parts by weight, the effect of improving the deformation recovery is small, and when it is less than 30 parts by weight, the moldability is impaired, which is not preferable.

The component ratio of the ethylene / α-olefin copolymer (B) is 5 to 70 parts by weight, preferably 10 to 70 parts by weight. The total of (A) and (B) is 100 parts by weight.

The hysteresis loss rate of the thermoplastic elastomer resin composition of the present invention at 23 ° C. is 30% or less. If the hysteresis loss rate is more than 30%, the elastic property is impaired, which is not preferable.

The strain recovery rate of the thermoplastic elastomer resin composition of the present invention at 45 ° C. is 70% or more. If the strain recovery rate is less than 70%, the deformation becomes large, which is not preferable.

The flexural modulus of the obtained thermoplastic elastomer composition is preferably in the range of 40 to 110 MPa because it has excellent cushioning properties.

According to JIS K 7210 of the obtained thermoplastic elastomer composition, the melt flow rate (MFR) measured at 190 ° C. and a load of 21.18 N is 0.1 to 10 g / 10 minutes, because the moldability is excellent. preferable.

Further, it is preferable that the tie molecule existence probability (P) is 0.20 or more because the deformation recovery property is not impaired.

The above-mentioned tie molecule existence probability (P) is equal to or higher than the critical molecular weight (Mc) at which the tie molecule can be formed in the relationship of molecular weight-elution amount obtained by gel permeation chromatography (GPC) measurement of the thermoplastic elastomer of the present invention. It can be calculated from the ratio of the elution area to the total elution area.

Here, the critical molecular weight (Mc) at which Thai molecules can be formed is determined by J.I. Polym. Sci. , Polym. Phys. Ed. , 29, 129 (1991), can be calculated by the following method with reference to the concept of Thai molecule formation. The details will be described below. Tie molecules are formed when the spread of the molecular chain in the molten state (average distance between molecular ends: r) is larger than the critical thickness (2 Lc + La) consisting of crystals and amorphous in the solid state. The critical condition in which is formed can be expressed by the following equation (I).

r = (2Lc + La) (I)
(In the formula, Lc is the crystal thickness and La is the amorphous thickness.)
In the case of an ethylene / α-olefin copolymer, r has a relationship of the following formula (II) with the molecular weight (M).

r = C _∞・ M / M ₀・ lv ² (II)
Here C∞ the characteristic ratio 6.8, _{M 0} is the backbone molecular weight 14, lv backbone bond length 1.53, M is the molecular weight.

Substituting the formula (II) into the formula (I), Mc is the same as M, so that the formula (III) is obtained, and the Thai molecule can be formed from the formula (III) by obtaining the values of Lc and La. The critical molecular weight (Mc) can be calculated.

Mc = 0.88 (2Lc + La) ² (III)
Further, Lc can be calculated by the following formula (IV) from the melting point (Tm) of the ethylene / α-olefin copolymer obtained by measurement using a differential scanning calorimeter (DSC).

Lc = (6.26 × 414) / (414-Tm) (IV)
(Here, the unit of Tm is [K].)
La can be calculated from Lc and the crystallinity (Xc) by the following equation (V).

La = (Lc (1-Xc)) / Xc (V)
Xc can be calculated by the following equation (VI) from the density (d) measured by the density gradient tube.

Xc = (d-0.86) /0.14d (VI)
The melting point of the thermoplastic elastomer resin composition of the present invention is preferably 80 ° C. or higher, which can maintain heat resistance, and more preferably 85 ° C. or higher because the heat resistance is improved. If necessary, polymer modifiers such as styrene isoprene copolymers, styrene butadiene copolymers, and hydrogenated copolymers thereof can be blended as polybutadienes, polyisoprenes, and styrene-based thermoplastic elastomers. Furthermore, phthalic acid ester-based, trimellitic acid ester-based, fatty acid-based, epoxy-based, adipic acid ester-based, polyester-based plasticizers, known hindered phenol-based, sulfur-based, phosphorus-based, and amine-based antioxidants, Hindered amine-based, triazole-based, benzophenone-based, benzoate-based, nickel-based, salicyl-based light stabilizers, antistatic agents, epoxy compounds, isocyanate compounds, carbodiimide compounds and other reactive groups, metal inactive agents , Organic and inorganic nucleating agents, neutralizing agents, antioxidants, antibacterial agents, fluorescent whitening agents, fillers, flame retardants, flame retardant aids, organic and inorganic pigments can be added.

The thermoplastic elastomer resin composition of the present invention has excellent deformation recovery and has heat resistance that can maintain its shape even in the summer or in an environment where the temperature tends to cause settling due to body temperature.

The molding method and application of the thermoplastic elastomer resin composition are not particularly limited, but it is used in applications where deformation recovery is required when the load is removed after the thermoplastic elastomer resin composition is continuously deformed by a continuous load.

For example, by injection molding or extrusion molding, a molded body having a flat plate, a rod shape, a spiral shape, a deformed cross section or a hollow cross section is applied to an application similar to a cushioning spring, or is applied to a support such as a cushion. Cases and the like can be mentioned. As an example, a three-dimensional network structure in which a continuous linear body composed of a plurality of strands obtained by extrusion molding is wound in a three-dimensional random loop shape, and at least a part of contact portions of the plurality of loops is fused. Examples thereof include a network structure having the above, and a structure composed of fiber aggregates exemplified in JP-A-2012-112072 and JP-A-5-163657.

Next, the present invention will be described with specific examples, but the present invention is not limited thereto. The evaluation of the characteristic values in the examples is as follows.
(1) Density Using a MI meter with a hood, a sample extruded at 190 ° C. with a load of 5 kg was slowly cooled in the hood for 5 minutes, and then measured with a density gradient tube at 23 ° C.
(2) GPC
The GPC in the present invention is measured under the following conditions.
[Device] HLC-8121GPC / HT manufactured by Tosoh Corporation
[Measurement conditions] Column: TSKgel GMHHR-H (20) HT x 3, eluent: trichlorobenzene + antioxidant (BHT 0.05%), flow velocity: 1.0 ml / min, sample concentration: 1.0 mg / ml , Injection volume: 0.3 ml, Column temperature: 140 ° C., Detector: HLC-8121 GPC / HT
(3) MFR
According to JIS K7210, the measurement was performed at a temperature of 190 ° C. and a load of 21.18 N.
(4) Strain recovery rate A 1 mm sheet was prepared under the conditions of a temperature of 200 ° C. and a cooling temperature of 10 ° C. using a compression molding machine (AWFA-50 manufactured by Shinto) having a strain recovery rate of 50 tons. A strip having a width of 10 mm and a length of 100 mm was cut out from the obtained sheet and marked with a distance of 50 mm before the test. Using a tensile tester (manufactured by RTG-1210 Orientec Co., Ltd.), it was fixed to a gripper having a distance of 50 mm in an atmosphere at a temperature of 45 ° C., deformed to 75 mm at a tensile speed of 50 mm / min, and held for 60 minutes. Then, the test piece was instantly removed from the grip, left for 10 minutes in an atmosphere of a temperature of 23 ° C., the distance marked was measured using a caliper, and the strain recovery rate was calculated by the following formula.

Strain recovery rate = distance before test / distance after test x 100
(5) Hysteresis loss rate A 1 mm sheet was produced under the conditions of a temperature of 200 ° C. and a cooling temperature of 10 ° C. using a compression molding machine (AWFA-50 manufactured by Shinto) having a hysteresis loss rate of 50 tons. A strip with a width of 10 mm and a length of 100 mm is cut out from the obtained sheet, fixed to a gripper with a distance of 50 mm, pulled to 25% at a speed of 50 mm / min, and the gripper is zeroed at the same speed without a hold time. Returned to.

The tensile energy (EC) indicated by the stress curve during tensile deformation and the tensile energy (EC') indicated by the stress curve during decompression were used, and the hysteresis loss was determined according to the following equation.

Hysteresis loss (%) = (EC-EC') / EC × 100
WC = ∫PdT (area when deformed from 0% to 25%)
WC'= ∫PdT (area when deformed from 25% to 0%)
Simply, it can be calculated by data analysis with a personal computer. (Average value of n = 5)
(6) Bending Elastic Modulus Bending Elastic Modulus Measured using a multipurpose test piece injection-molded under predetermined conditions in accordance with JIS-K6922-2 under the conditions of a span of 64 mm and a bending speed of 2 mm / min.

Examples of synthesis in the examples are described below as examples of production of an ethylene / α-olefin copolymer.

Manufacturing example 1
[Preparation of modified clay compound]
29.7 g of N, N-dimethyl-octadecylamine and 10 mL of 37% hydrochloric acid were added to 500 mL of deionized water to prepare an aqueous solution of N, N-dimethyl-octadecylammonium hydrochloride. 100 g of montmorillonite having an average particle size of 7.8 μm (prepared by pulverizing Kunipia F (manufactured by Kunimine Industries) with a jet pulverizer) was added to the above-mentioned aqueous hydrochloride solution and reacted for 6 hours. After completion of the reaction, the reaction solution was filtered, and the obtained cake was dried under reduced pressure for 6 hours to obtain 120 g of a modified clay compound. The amount of organic cation introduced was 1.0 mmol / g.
[Catalyst preparation]
In a 20 L stainless steel container under a nitrogen atmosphere, add 3.3 L of heptane, a hexane solution of triethylaluminum (TEAL) (20 wt% diluted product) to 1.125 mol (0.9 L) per aluminum atom, and according to [Preparation of Modified Clay Compound]. 38 g of the prepared modified clay compound was added, and the mixture was stirred for 1 hour. 1.25 mmol of diphenylmethylene (4-phenyl-1-indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride synthesized according to Production Example 1 was added thereto, and the mixture was stirred for 12 hours. A catalyst was prepared by adding 5.8 L of an aliphatic saturated hydrocarbon solvent (IP Solvent 2835 (manufactured by Idemitsu Petrochemical Co., Ltd.)) to the obtained suspension system (zirconium concentration 0.125 mmol / L).
[polymerization]
Polymerization was carried out using a tank reactor. Ethylene and hexene-1 were continuously press-fitted into the reactor to set the total pressure to 950 kgf / cm ² , the ethylene concentration to 65 mol%, and the hexene-1 concentration to 35 mol%. Then, the reactor was stirred at 1500 rpm.

Then, the prepared catalyst was continuously supplied to the reactor, and polymerization was carried out so that the average temperature was maintained at 200 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 900 kg / m ³ and an MFR of 0.1 g / 10 minutes was obtained.

Manufacturing example 2
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 70 mol%, the hexene-1 concentration was 30 mol%, and the polymerization was carried out so that the average temperature was maintained at 225 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 905 kg / m ³ and an MFR of 4.0 g / 10 minutes was obtained.

Manufacturing example 3
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 72 mol%, the hexene-1 concentration was 28 mol%, and the polymerization was carried out so that the average temperature was maintained at 250 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 905 kg / m ³ and an MFR of 20 g / 10 minutes was obtained.

Manufacturing example 4
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 70 mol%, the hexene-1 concentration was 30 mol%, and the polymerization was carried out so that the average temperature was maintained at 220 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 905 kg / m ³ and an MFR of 1.0 g / 10 minutes was obtained.

Production example 5
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 72 mol%, the hexene-1 concentration was 28 mol%, and the polymerization was carried out so that the average temperature was maintained at 240 ° C. As a result, an ethylene / hexene copolymer-1 having a density of 905 kg / m ³ and an MFR of 12 g / 10 minutes was obtained.

Production example 6
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 75 mol%, the hexene-1 concentration was 25 mol%, and the polymerization was carried out so that the average temperature was maintained at 220 ° C. As a result, an ethylene / hexene copolymer-1 having a density of 910 kg / m ³ and an MFR of 1.0 g / 10 minutes was obtained.

Production example 7
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 75 mol%, the hexene-1 concentration was 25 mol%, and the polymerization was carried out so that the average temperature was maintained at 240 ° C. As a result, an ethylene / hexene copolymer-1 having a density of 910 kg / m ³ and an MFR of 12 g / 10 minutes was obtained.

Production Example 8
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 75 mol%, the hexene-1 concentration was 25 mol%, and the polymerization was carried out so that the average temperature was maintained at 210 ° C. As a result, an ethylene / hexene copolymer-1 having a density of 910 kg / m ³ and an MFR of 0.5 g / 10 minutes was obtained.

Manufacturing example 9
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 65 mol%, the 1-hexene concentration was 35 mol%, and the polymerization was carried out so that the average temperature was maintained at 230 ° C. As a result, an ethylene / 1-hexene copolymer having a density of 900 kg / m ³ and an MFR of 8.0 g / 10 minutes was obtained.

Production Example 10
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 63 mol%, the hexene-1 concentration was 37 mol%, and the polymerization was carried out so that the average temperature was maintained at 210 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 895 kg / m ³ and an MFR of 2.0 g / 10 minutes was obtained.

Production Example 11
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 80 mol%, the hexene-1 concentration was 20 mol%, and the polymerization was carried out so that the average temperature was maintained at 210 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 928 kg / m ³ and an MFR of 0.5 g / 10 minutes was obtained.

Production Example 12
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 80 mol%, the hexene-1 concentration was 20 mol%, and the polymerization was carried out so that the average temperature was maintained at 240 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 930 kg / m ³ and an MFR of 12 g / 10 minutes was obtained.

Production Example 13
[polymerization]
The polymerization was carried out in the same manner as in Production Example 1 except that the ethylene concentration was 63 mol%, the hexene-1 concentration was 37 mol%, and the polymerization was carried out so that the average temperature was maintained at 260 ° C. As a result, an ethylene-hexene-1 copolymer having a density of 900 kg / m ³ and an MFR of 40 g / 10 minutes was obtained.

Example 1
As the ethylene / α-olefin copolymer (A), the ethylene / hexene-1 copolymer and the ethylene / α-olefin ^{copolymer having a density of 905 kg / m 3 and an MFR of 4.0 g / 10 minutes polymerized in Production Example 2 (} As B), an ethylene / hexene-1 copolymer having a density of 900 kg / m ³ and an MFR of 0.1 g / 10 min, which was polymerized in Production Example 1, was blended at 90/10 (part by weight / part by weight), and a twin-screw extruder was used. Using (manufactured by Toyo Seiki Co., Ltd.), melt-kneading was carried out under the conditions of a screw rotation speed of 20 rpm and a barrel set temperature of 220 ° C. to obtain a thermoplastic elastomer resin composition.

The obtained thermoplastic elastomer resin composition had a strain recovery rate of 75% and a hysteresis loss rate of 27%, and were excellent in heat resistance and recovery.

Example 2
As the ethylene / α-olefin copolymer (A), the ethylene / hexene-1 copolymer and the ethylene / α-olefin copolymer (B) polymerized in Production Example 3 at a density of 905 kg / m ^{3 and MFR of 20 g / 10 minutes.} The same method as in Example 1 was prepared by blending an ethylene / hexene-1 copolymer having a density of 905 kg / m ^{3 and an MFR of 1.0 g / 10 minutes polymerized in Production Example 4 at 30/70 (parts by weight / part by weight).} Obtained a thermoplastic elastomer resin composition in the above.

The obtained thermoplastic elastomer resin composition had a strain recovery rate of 79% and a hysteresis loss rate of 27%, and were excellent in heat resistance and recovery.

Example 3
As the ethylene / α-olefin copolymer (A), the ethylene / hexene-1 copolymer and the ethylene / α-olefin copolymer (B) polymerized in Production Example 7 having a density of 910 kg / m ^{3 and an MFR of 12 g / 10 min.} The same method as in Example 1 was prepared ^{by blending an ethylene / hexene-1 copolymer having a density of 910 kg / m 3} and an MFR of 1.0 g / 10 minutes polymerized in Production Example 6 at 70/30 (parts by weight / part by weight). Obtained a thermoplastic elastomer resin composition in the above.

The strain recovery rate of the obtained thermoplastic elastomer resin composition was 73%, and the hysteresis loss rate was 28%, which were excellent in heat resistance and recovery property.

Example 4
As the ethylene / α-olefin copolymer (A), the ethylene / hexene-1 copolymer and the ethylene / α-olefin copolymer (B) polymerized in Production Example 9 having a density of 900 kg / m ^{3 and an MFR of 8 g / 10 minutes.} As a result, the ethylene / hexene-1 copolymer having a density of 910 kg / m ³ and an MFR of 0.5 g / 10 min, which was polymerized in Production Example 8, was blended with 80/20 (parts by weight / part by weight) in the same manner as in Example 1. A thermoplastic elastomer resin composition was obtained.

The obtained thermoplastic elastomer resin composition had a strain recovery rate of 74% and a hysteresis loss rate of 27%, and were excellent in heat resistance and recovery.

Comparative Example 1
The ethylene / hexene-1 copolymer having a density of 905 kg / m ³ and an MFR of 12 g / 10 minutes polymerized in Production Example 5 has a strain recovery rate of 68% and a hysteresis loss rate of 33%, and has excellent heat resistance and strain recovery. It was low.

Comparative Example 2
As the ethylene / α-olefin copolymer (A), the ethylene / hexene-1 copolymer and the ethylene / α-olefin copolymer (B) polymerized in Production Example 12 at a density of 930 kg / m ^{3 and MFR of 12 g / 10 minutes.} The same method as in Example 1 was prepared ^{by blending an ethylene / hexene-1 copolymer having a density of 895 kg / m 3} and an MFR of 2.0 g / 10 min, which was polymerized in Production Example 10, at 60/40 (parts by weight / part by weight). Obtained a thermoplastic elastomer resin composition in the above.

The obtained thermoplastic elastomer resin composition had a strain recovery rate of 62% and a hysteresis loss rate of 39%, which were inferior in heat resistance and strain recovery.

Comparative Example 3
As the ethylene / α-olefin copolymer (A), the ethylene / hexene-1 copolymer and the ethylene / α-olefin copolymer (B) polymerized in Production Example 13 at a density of 900 kg / m ^{3 and MFR of 40 g / 10 minutes.} The same method as in Example 1 was prepared by blending an ethylene / hexene-1 copolymer having a density of 928 kg / m ^{3 and an MFR of 0.5 g / 10 min, which was polymerized in Production Example 11, at 50/50 (parts by weight / part by weight).} Obtained a thermoplastic elastomer resin composition in the above.

The obtained thermoplastic elastomer resin composition had a strain recovery rate of 63% and a hysteresis loss rate of 34%, which were inferior in heat resistance and strain recovery.

Claims (3)

Ethylene / α-olefin copolymer (A) having a density of 900 to 920 kg / m ³ and a weight average molecular weight measured by GPC in the range of 40,000 to 100,000 (A) 30 to 95 parts by weight and a density of 890 to 920 kg / m 3. m ³ , Weight average molecular weight measured by GPC is in the range of 110,000 to 250,000 Ethylene / α-olefin copolymer (B) 5 to 70 parts by weight ((A) and (B) total 100 weight The composition contains (parts), and the hysteresis loss rate at 23 ° C. below is 30% or less, the strain recovery rate at 45 ° C. below is 70% or more, and the bending elasticity below is 40 to 110 MPa. A thermoplastic elastomer resin composition in the range.
The α-olefin is one or two selected from butene-1, penten-1, hexene-1, 4-methyl-1-pentene, heptene-1, octene-1, nonene-1, and decene-1. That is all.
Strain recovery rate: A 1 mm sheet was produced under the conditions of a temperature of 200 ° C. and a cooling temperature of 10 ° C. using a compression molding machine. A strip having a width of 10 mm and a length of 100 mm was cut out from the obtained sheet and marked with a distance of 50 mm before the test. It was fixed to a gripper having a distance of 50 mm in an atmosphere of a temperature of 45 ° C. using a tensile tester, deformed to 75 mm at a tensile speed of 50 mm / min, and held for 60 minutes. Then, the test piece was instantly removed from the grip, left for 10 minutes in an atmosphere of a temperature of 23 ° C., the distance marked was measured using a caliper, and the strain recovery rate was calculated by the following formula.
Strain recovery rate = distance before test / distance after test x 100
Hysteresis loss rate: A 1 mm sheet was produced under the conditions of a temperature of 200 ° C. and a cooling temperature of 10 ° C. using a compression molding machine. A strip with a width of 10 mm and a length of 100 mm is cut out from the obtained sheet, fixed to a gripper with a distance of 50 mm, pulled to 25% at a speed of 50 mm / min, and the gripper is zeroed at the same speed without a hold time. Returned to.
Tensile energy (EC) indicated by stress curve during tensile deformation, tensile energy indicated by stress curve during decompression
Hysteresis loss was calculated according to the following formula using ruggy (EC').
Hysteresis loss (%) = (EC-EC') / EC × 100
WC = ∫PdT (area when deformed from 0% to 25%)
WC'= ∫PdT (area when deformed from 25% to 0%)
Bending elastic modulus: Bending elastic modulus Measured using a multipurpose test piece injection-molded under predetermined conditions in accordance with JIS-K6922-2 under the conditions of a span of 64 mm and a bending speed of 2 mm / min. The olefin-based thermoplastic elastomer composition according to claim 1, wherein the tie molecule presence probability (P) is 0.20 or more. The olefin-based thermoplastic elastomer composition according to claim 1 or 2, wherein the MFR is in the range of 0.1 to 10 g / 10 minutes.