JP2000309676A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition excellent in flexibility, mechanical strength, thermofusing strength and profile extrusion molding processability, slight in stickiness of the products, and also slight in bleeding. SOLUTION: This composition comprises the following four components 1 to 4: (1) 30-70 wt.% of a hydrogenated product with a weight-average molecular weight of 100,000-450,000 made from a block copolymer A made up of polymer block composed of vinyl aromatic hydrocarbon unit and polymer block B composed of conjugated diene unit, wherein the polymer block A accounts for 10-50 wt.% of the copolymer, (2) 70-30 wt.% of a hydrocarbon-based rubber flexibilizer, (3) 3-50 wt.% of a propylene-based polymer with a melt flow rate (MFR) of 0.01-100 g/10 min, and (4) 3-80 wt.% of a copolymer with a melt flow rate (MFR) of 1-40 g/10 min and density of 0.86-0.91 g/cm3 made from ethylene and a 4-20C α-olefin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition, and more particularly to a thermoplastic elastomer composition which is excellent in flexibility, mechanical strength, heat-sealing strength and profile extrusion processability, has low stickiness of a product, and has little bleed. The present invention relates to an elastomer composition. This composition is used for food, daily necessities, toys and sports equipment, stationery such as desk mats, interior and exterior of automobiles, civil engineering and construction such as civil engineering sheets and waterproof sheets, AV and household electrical appliances, OA. Office equipment applications, clothing and footwear applications, textile applications, medical device applications such as various catheters, sanitary products such as disposable diapers and sanitary products, chemical and mining and industrial materials, packaging and transport materials, agricultural and livestock and fishery materials, etc. It can be used in a wide range of fields, and can be suitably used for electric refrigerator gaskets, various gaskets for building materials, molding materials for automobiles, etc., taking advantage of its properties such as excellent profile extrusion workability and excellent heat fusion strength. .

[0002]

2. Description of the Related Art In recent years, a thermoplastic elastomer (hereinafter abbreviated as "TPE") which is a rubber-like soft material and which does not require a vulcanizing step and has the same moldability as a thermoplastic resin.
Are attracting attention and used in the fields of automobile parts, home electric parts, medical and food equipment parts, electric wires and miscellaneous goods. For such TPE, polyolefins,
Compositions based on various resins such as polystyrene, polyurethane, polyester, and vinyl chloride resin have been developed and are commercially available.

However, these materials have drawbacks in strength, flexibility, profile extrusion processability, economy, recyclability, etc., and have not always been satisfactory. Among these TPEs, polystyrene-based TPEs such as styrene-butadiene-styrene block copolymer (SBS) and styrene-isoprene-styrene block copolymer (SIS) are rich in flexibility and have good rubber elasticity. However, since it has a double bond in the diene-derived block in the polymer, it may have a problem in terms of heat aging resistance (thermal stability) and weather resistance.

[0004] By hydrogenating the double bond of this block copolymer, the thermal stability can be improved,
JP-A-58-206644 discloses a composition in which a hydrogenated derivative of such a vinyl aromatic-conjugated diene compound block copolymer is combined with a softener for a mineral oil rubber, a propylene polymer, and an inorganic filler. Is disclosed.
This composition was excellent in flexibility, rubber elasticity, strength, and profile extrusion property as compared with the olefin-based TPE composition, but was inferior in heat seal strength. On the other hand, as a composition having improved heat fusion strength, a hydrogenated derivative of a vinyl aromatic-conjugated diene compound block copolymer was combined with a mineral oil-based rubber softener and a specific ethylene-α-olefin copolymer. A composition has been proposed in JP-A-11-21415. However, this composition has a problem that bleeding occurs although the heat-fusibility is improved.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems, to be excellent in flexibility, mechanical strength, heat-sealing strength and profile extrusion processability, to reduce stickiness of products, and An object of the present invention is to provide a thermoplastic elastomer composition having less bleed.

[0006]

The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, have found that the hydrogen of a block copolymer composed of a specific vinyl aromatic hydrocarbon block and a conjugated diene block has been obtained. Additive derivative, softener for hydrocarbon rubber, propylene resin, and specific ethylene-α
-It has been found that a thermoplastic elastomer composition free from the above-mentioned problems can be obtained by combining an olefin copolymer, and the present invention has been completed.

That is, the gist of the present invention is as follows:
(B) a thermoplastic elastomer composition containing the four components (c) and (d). (A) A hydrogenated product of a block copolymer represented by the following general formula (1) or (2), wherein the weight average molecular weight is 100,000 to 450,000, and the polymer block (A) is the copolymer. When the proportion of which is 10 to 50% by weight: 30 to 70% by weight (however, the total amount of the component (a) and the component (b) is 100% by weight
And

[0008]

Embedded image A- (BA) n (1)

[0009]

(AB) n (2)

Wherein A is a polymer block composed of vinyl aromatic hydrocarbon units, B is a polymer block composed of conjugated diene units, and n is an integer of 1 to 5. (b) Hydrocarbon rubber Softener for use: 70 to 30% by weight (c) Propylene polymer having a melt flow rate (MFR) of 0.01 to 100 g / 10 min: 3 to 50 parts by weight (however, component (a), (b) (D) a melt flow rate (MFR) of 1 to 40 g / 10 min, a maximum melting peak temperature of 95 ° C. or lower by a differential scanning calorimeter (DSC), and Density 0.86-0. 91 g / cm ³ of a copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms: 3 to 80 parts by weight

Another gist of the present invention is that the block copolymer of the component (a) is a styrene-butadiene block copolymer,
Styrene-isoprene block copolymer and styrene-
The above thermoplastic elastomer composition, which is at least one type of block copolymer selected from the group consisting of butadiene / isoprene block copolymers, is also present in the above-mentioned thermoplastic elastomer composition. The above-mentioned thermoplastic elastomer composition wherein the propylene-based polymer is a propylene homopolymer or a propylene-ethylene copolymer, and the α-olefin constituting the ethylene-α-olefin copolymer (d) is butene- At least one α- selected from the group consisting of 1, hexene-1, and octene-1
The above thermoplastic elastomer composition which is an olefin,
Also exists.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail. The block copolymer used as the component (a) in the composition of the present invention is a hydrogenated derivative of a vinyl aromatic hydrocarbon / conjugated diene block copolymer represented by the general formula (1) or (2) ( Hereinafter, it may be abbreviated as “hydrogenated block copolymer”).

[0013]

Embedded image A- (BA) n (1)

[0014]

(AB) n (2)

(Where A is a polymer block composed of vinyl aromatic hydrocarbon units, B is a polymer block composed of conjugated diene units, and n is an integer of 1 to 5). The weight average molecular weight of the added block copolymer needs to be in the range of 100,000 to 450,000.
The more preferable weight average molecular weight is 150,000 to 400,000, further preferably 200,000 to 350,000. Weight average molecular weight of 10
If it is less than 10,000, the obtained thermoplastic elastomer composition will have poor mechanical strength and thermal fusion strength, and if it exceeds 450,000, the viscosity at the time of melting will be high and molding processability will be poor. The “weight average molecular weight” referred to in the present invention is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions.

(Measurement conditions) Instrument: 150C ALC / GPC (manufactured by MILLIPORE) Column: AD80M / S (manufactured by Showa Denko KK) 3 detectors: FOXBORO infrared spectrophotometer MIRAN1A, measurement wavelength 3 42 μm Solvent: o-dichlorobenzene Temperature: 140 ° C. Flow rate: 1 ml / min Injection volume: 200 μl Concentration: 2 mg / ml (2,6-di-t-butyl-p-phenol as an antioxidant) 0.2% by weight)

Styrene is preferred as the vinyl aromatic hydrocarbon as a monomer constituting the polymer block (A).
Also, α-methylstyrene and the like can be used. The conjugated diene monomer constituting the polymer block (B) is preferably butadiene or isoprene, or a mixture of both. When the polymer block (B) is composed of only butadiene, the block having a 1,2-addition structure in the microstructure of 20 to 50% retains the properties as an elastomer after hydrogenation. Preferred above. A more preferred ratio of the 1,2-addition structure is 35 to 45.
%. The molecular structure of the hydrogenated block copolymer is
It may be linear, branched, radial or any combination thereof.

Formulas (1) and (2) of this block copolymer
Is an integer of 1 to 5. When n exceeds 5, the production becomes complicated and it is not economical, and when it exceeds 5, the effect is not remarkably improved. In addition, when n is less than 1, it does not become a block copolymer. In addition, as a more preferable block copolymer, Formula (1)
Is a block copolymer having a basic structure of “ABA type”. The proportion of the polymer block (A) in the copolymer is 10 to 50% by weight, preferably 15 to 45%.
%, More preferably 20 to 40% by weight. When the content ratio of the polymer block (A) is less than 10% by weight, the obtained thermoplastic elastomer composition has poor mechanical strength and thermal fusion strength. On the other hand, if this proportion exceeds 50% by weight, the flexibility and the profile extrusion moldability are inferior, and the bleeding tends to deteriorate.

As a method for producing the block copolymer used in the present invention, any production method may be used as long as the above-mentioned structure and physical properties can be obtained. For example,
It can be obtained by performing block polymerization in an inert solvent using a lithium catalyst or the like according to a method described in JP-A-23798. The hydrogenation treatment of these block copolymers is described, for example, in JP-B-42-870.
No. 4, JP-B-43-6636, or JP-A-59-133203 and JP-A-60-790.
The reaction can be carried out in an inert solvent in the presence of a hydrogenation catalyst according to the method described in JP-A-05-2005. In this hydrogenation treatment, at least 50%, preferably 80% or more of the olefinic double bond in the polymer block (B) is hydrogenated, and the aromatic unsaturated bond in the polymer block (A) is It is preferable to carry out the process so that only 25% or less is hydrogenated. A commercially available product of such a hydrogenated block copolymer is “KRATON-G”.
(Shell Chemical Co., Ltd.), "Septon" (Kuraray Co., Ltd.), "Toughtec" (Asahi Kasei Corporation) and the like.

As the softener for hydrocarbon rubber used as the component (b) in the present invention, mineral oil-based and synthetic resin-based softeners are suitable. Mineral oil-based softeners are generally a mixture of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Paraffinic hydrocarbons having 50% or more of the total carbon atoms are paraffinic. On the other hand, naphthenic hydrocarbons having 30 to 45% of carbon atoms are called naphthenic oils and aromatic hydrocarbons having 35% or more of carbon atoms are called aromatic oils. ing. Among these, a paraffinic oil is preferable as the softening agent for hydrocarbon rubber used in the present invention.

The paraffinic oil has a kinematic viscosity at 40 ° C. of 20 to 800 cst (centistokes), preferably 50 to 600 cst, a fluidity of 0 to −40 ° C., preferably 0 to −30 ° C., and a flash point (COC). Law) is 200
C. to 400.degree. C., preferably 250 to 350.degree. C. are suitably used. As the synthetic resin-based softening agent, polybutene, low molecular weight polybutadiene and the like can be used, but the above-mentioned mineral oil-based softening agent is more preferable. In the present invention (c)
The propylene-based polymer used as the component includes propylene homopolymer, propylene / ethylene copolymer, propylene / butene-1 copolymer, propylene / ethylene / butene-1 copolymer, propylene / 4-methylpentene-
One copolymer may be used, and any of these may be used alone or in combination. Of these, propylene homopolymer and propylene / ethylene copolymer are preferred. In the propylene / ethylene copolymer, the proportion of the non-crystalline portion in the copolymer is more preferably 25% by weight or less, and the propylene content in the non-crystalline portion is 10 to 50% by weight. Is desirable.

The melt flow rate (MFR) of the propylene polymer used as the component (c) in the present invention is JIS
As a value at a temperature of 230 ° C. and a load of 2.16 kg, measured in accordance with Table 1 and Condition 14 of K-7210, 0.01 to
It must be in the range of 100 g / 10 minutes. If the melt flow rate is less than 0.01 g / 10 min, the melt viscosity during processing tends to be high and the workability tends to be poor. If the melt flow rate exceeds 100 g / 10 min, the rigidity decreases and the heat fusion occurs. The effect of improving the strength cannot be obtained.
A more preferred range of the melt flow rate is 0.1 to 50.
g / 10 minutes.

The ethylene-α-olefin copolymer used as the component (d) in the present invention is a copolymer containing ethylene and α-olefin as main components. The α-olefin copolymerized with ethylene has 4 to 2 carbon atoms.
It is one or a mixture of two or more selected from 0, preferably 4 to 12 α-olefins, and a straight-chain or branched one may be used. Specific examples of the α-olefin include butene-1, hexene-1, 4-methylpentene-1,
Octene-1, decene-1 and the like.
1, hexene-1, and octene-1 are preferred.

The ethylene-α-olefin copolymer
Density is 0.86-0.91 g / cm ^Three, Preferably 0.
87 ~ 0.905g / cm^Three, More preferably 0.87
5 to 0.90 g / cm^ThreeIt is. 0.86g / c density
m^ThreeIn less than the obtained thermoplastic elastomer composition
The strength is reduced and the effect of improving the heat fusion strength cannot be obtained. Ma
The density is 0.91 g / cm^ThreeExceeds this, the flexibility is reduced
Is not preferred.

The ethylene-α-olefin copolymer (d) has a melt flow rate (MFR) of 1 to 40 g / 10 minutes, preferably 1.5 to 40 g / 10 minutes.
30 g / 10 min, more preferably 2 to 20 g / 10 min is used. If the melt flow rate is less than 1 g / 10 minutes, bleeding from the obtained thermoplastic elastomer composition becomes a problem, which is not preferable.
If the time is higher than 0 minutes, the effect of improving the heat fusion strength cannot be obtained.

The maximum melting peak temperature of the ethylene-α-olefin copolymer determined by a differential scanning calorimeter (DSC) is 95 ° C. or lower, preferably 90 ° C. or lower. If the peak temperature exceeds 95 ° C., the moldability deteriorates, which is not preferable. In addition, the maximum melting peak temperature was measured by a differential scanning calorimeter (DSC) by raising the temperature of the sample to 170 ° C., holding the sample for 5 minutes, and melting the sample, and then reducing the temperature by 10 ° C./min.
The measurement was performed based on an endothermic peak curve obtained by cooling to 0 ° C., holding for 1 minute, heating to 170 ° C. at a rate of 10 ° C./min, and measuring.

The above ethylene-α-olefin copolymer can be produced, for example, by a gas-phase fluidized-bed method, a solution method, a slurry method, a high-pressure polymerization method, or the like. In this polymerization, a small amount of a diene component such as dichloropentadiene and ethylidene norbornene may be copolymerized. Examples of the polymerization catalyst include titanium compounds such as titanium halides, vanadium compounds, organoaluminum / magnesium complexes such as alkylaluminum / magnesium complexes and alkylalkoxyaluminum / magnesium complexes, and organometallic compounds such as alkylaluminum or alkylaluminum chloride. So-called Ziegler-type catalyst, or International Publication W
Examples thereof include metallocene catalysts described in O 91/04257 and the like. The catalyst referred to as the metallocene catalyst may not contain alumoxane, but it is preferable to use a catalyst obtained by combining a metallocene compound and alumoxane (a so-called Kaminsky catalyst).

The proportion of each component constituting the thermoplastic elastomer composition of the present invention is preferably 30 to 70% by weight, more preferably 30 to 70% by weight based on 100% by weight of the total amount of the components (A) and (B). Is 35 to 65% by weight, more preferably 3% by weight.
5 to 60% by weight. If the amount of the component (a) is less than 30% by weight, the resulting thermoplastic elastomer will have poor strength and thermal fusion strength, and will have poor bleeding properties. On the other hand, when the amount of the component (a) exceeds 70% by weight, flexibility and moldability deteriorate. The amount of the component (c) is (a) and (b)
When the total amount of the components is 100 parts by weight, 3 to 50 parts by weight, preferably 5 to 45 parts by weight, and more preferably 10 to 50 parts by weight.
40 parts by weight. If the amount is less than 3 parts by weight, the moldability deteriorates. If the amount exceeds 50 parts by weight, the flexibility of the thermoplastic elastomer composition is impaired. The amount of the component (d) is 10 times the total amount of the components (a) and (b).
3 to 80 parts by weight, preferably 5 to 7 parts by weight
0 parts by weight, more preferably 10 to 60 parts by weight. If the amount is less than 3 parts by weight, the moldability of the obtained thermoplastic elastomer composition is inferior, and the effect of improving the heat fusion strength is small. On the other hand, if the amount exceeds 80 parts by weight, the flexibility of the thermoplastic elastomer composition is lost, and at the same time, the bleeding property is deteriorated.

In the thermoplastic elastomer composition of the present invention, in addition to the above essential components, other optional components can be blended according to various purposes within a range not to impair the effects of the present invention. Examples of the components used as such components include fillers, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizing agents, lubricants, antifogging agents, antiblocking agents, slip agents, and dispersants. Agents, colorants, flame retardants,
Various additives such as an antistatic agent, a conductivity-imparting agent, a cross-linking agent, a cross-linking auxiliary, a metal deactivator, a molecular weight regulator, a bactericide, a fungicide, and a fluorescent whitening agent; Plastic resins, elastomers and the like other than the above essential components, and the like,
Any of these can be used alone or in combination.

Examples of the thermoplastic resin other than the above essential components include ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid ester copolymer, Ethylene and α such as ethylene and methacrylate copolymer
-Olefin copolymer, polyethylene, polybutene-1
Polyolefin resins such as resins, polyphenylene ether resins, polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyoxymethylene resins such as polyoxymethylene homopolymer and polyoxymethylene copolymer. Resins, polymethyl methacrylate resins and the like can be mentioned.

Examples of the elastomer include ethylene / propylene copolymer rubber (EPM), ethylene / propylene / non-conjugated diene copolymer rubber (EPDM), ethylene / butene copolymer rubber (EBM), and ethylene / propylene / butene copolymer. Ethylene-based elastomers such as polymerized rubber,
Styrene-based elastomers such as styrene-butadiene copolymer rubber and styrene-isoprene copolymer rubber, and polybutadiene can be exemplified. Further, examples of the filler include glass fiber, hollow glass sphere, carbon fiber, talc, calcium carbonate, mica, potassium titanate fiber, silica, titanium dioxide, and carbon black.

The thermoplastic elastomer composition of the present invention comprises:
For example, it can be manufactured by a method of mechanically melting and kneading the above components. Examples of the melt kneader that can be used here include a single screw extruder, a twin screw extruder, a Brabender plastograph, a Banbury mixer, a kneader blender, and a roll mill.
The kneading temperature is preferably in the range of 145 to 300 ° C. When kneading, even if all the components are kneaded at once,
Alternatively, a multi-stage kneading method may be used in which an arbitrary component is kneaded, and then the other remaining components are added and kneaded. The thermoplastic elastomer composition obtained as described above can be produced by, for example, injection molding (insert molding, two-color molding, sandwich molding, gas injection molding, etc.), extrusion molding, inflation molding, T-die film. Molding method,
Various molded articles can be processed by a molding method such as a laminate molding method, a blow molding method, a hollow molding method, a compression molding method, and a calendar molding method. In particular, the compositions of the present invention are useful for profile extrusion. Molded products obtained in this way are used for automobile parts, industrial parts such as home electric parts, food packaging materials,
It can be used for medical equipment parts, furniture parts, daily necessities and the like. Since the composition of the present invention is particularly excellent in profile extrusion processability and heat fusion strength, it is suitable for electric refrigerator gasket materials, various gasket materials for building materials, molding materials for automobiles, and the like.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited by the following Examples unless it exceeds the gist of the invention.

<Evaluation Method> Preparation of Measurement Sample Composition 100 mixed in a prescribed composition (Tables 3 and 4)
A phenolic antioxidant (trade name “Irganox 1010”, manufactured by Ciba Geigy Co., Ltd.) based on parts by weight
0.1 part by weight was added, and the mixture was melt-kneaded at a temperature of 200 ° C. using a twin screw extruder having an L / D of 33 and a cylinder diameter of 45 mm to obtain a thermoplastic elastomer composition pellet. This pellet is in-line screw type injection molding machine (Toshiba Machine Co., Ltd. small injection molding machine: IS90B).
Using an injection pressure of 500 kg / cm ² and an injection temperature of 20
Molded at 0 ° C and mold temperature of 30 ° C, 120mm x 8
A sheet having a thickness of 0 mm × 2 mm was prepared. This sheet was heated at a temperature of 2.
After melting at 00 ° C for 7 minutes, 50 kg / cm ² at the same temperature
For 3 minutes, and then cooled to 40 ° C.
cm ² for 2 minutes, 200mm x 200mm x 2m
m was formed into a sheet. The following measurement was performed using this sheet.

(1) Flexibility The JIS-A hardness was measured according to JIS-K6301. (2) Density Measured by the underwater displacement method according to JIS-K7112. (3) Mechanical strength (tensile strength) JIS-K
The tensile strength at break (kg / cm ² ) was measured according to 6301. (4) Melt flow rate (MFR) According to JIS-K7210, Table 1, condition 14, temperature 2
The measurement was performed at 30 ° C. and a load of 2.16 kg. (5) Maximum melting peak temperature Using a differential scanning calorimeter DSC measurement device (manufactured by Seiko Instruments Inc.), the sample was heated to 170 ° C., held for 5 minutes to melt, and then cooled at a rate of 10 ° C. / The temperature was raised to 170 ° C. at a rate of 10 ° C./min, and measured from an endothermic peak curve obtained when the temperature was measured at a rate of 10 ° C./min. (6) Heat fusion strength The press sheet obtained above is 90 mm long and 10 m wide.
m and cut the center using a cutter knife. The cut surface was brought into contact with an iron plate at a temperature of 250 ° C. for 5 seconds, and the end surfaces were immediately pressure-bonded and thermally fused. This sample is
After holding at 48 ° C. for 48 hours, a tensile test was performed under the conditions of a chuck interval of 400 mm and a tensile speed of 200 mm / min, and the thermal fusion strength was measured. (7) Evaluation of deformed extrusion moldability Using a 40 mmφ single screw extruder (manufactured by Mitsubishi Heavy Industries, Ltd.) at a screw rotation speed of 70 rpm and a temperature of 180 ° C.
The shape of the molded product extruded from the die having the shape shown in FIG. 1 was evaluated. The reflectivity of the mouth shape of the molded product and the surface state were visually judged, and those having no problems such as uneven thickness and cut edges were evaluated as good. (8) Bleed After the injection molded sheet was allowed to stand in a gear oven at 80 ° C for one week, the presence or absence of bleed was visually evaluated.

<Blending Components> The blending components used in the examples and comparative examples are as follows. (A) Component The block structure of the hydrogenated product of the vinyl aromatic hydrocarbon / conjugated diene block copolymer (A-1 to 4) used as the component (A), and the polymer blocks (A) and (B) are constituted. The monomer, weight average molecular weight and content of the polymer block (A) are as shown in Table 1.

[0037]

[Table 1]

Note 1) Monomers (A) and (B): monomers constituting polymer blocks (A) and (B) 2) Mw: weight average molecular weight 3) (A) content: weight Polymer block in coalescence (A)
Content of

(B) Component As the softener for hydrocarbon rubber as the component (b), a paraffinic oil having the following physical properties was used. Product name: "PW380" (manufactured by Idemitsu Kosan Co., Ltd.) 40 ° C kinematic viscosity: 381.6 cst Flow rate: -15 ° C Flash point: 300 ° C

(C) Component As the propylene polymer of the component (C), the following two types were used. However, "MFR" is a melt flow rate. (C-1) Propylene-ethylene copolymer Product name: "SPX9800" (manufactured by Mitsubishi Chemical Corporation) MFR: 1.0 g / 10 minutes (230 ° C, 2.16 kg) (C-2) Propylene homopolymer “TA8” (manufactured by Nippon Polychem) MFR: 0.9 g / 10 min (230 ° C., 2.16 kg)

(D) Component α-olefin unit of the ethylene-α-olefin copolymer used as component (d), melt flow rate (MF
Table 2 shows R), density, and maximum melting peak temperature by a differential scanning calorimeter.

[0042]

[Table 2] Note 1) MFR: Melt flow rate (230 ° C, 2.16 kg) 2) Tm: Maximum melting peak temperature by differential scanning calorimeter

Other Components In addition to the essential components (a) to (d) above, this Example 12
Then, calcium carbonate ("Yukalite A-1" manufactured by Mitsubishi Chemical Corporation) was added to the composition as an inorganic filler.

<Examples 1 to 12, Comparative Examples 1 to 9> Table 3
(Examples) and Table 4 (Comparative Examples) collectively show the composition of each composition, and the flexibility, mechanical strength, heat fusion strength, profile extrusion moldability, and the like of the molded article measured according to the above.

<Evaluation of Result> The following points are clarified by comparing the example with the comparative example. (1) In Comparative Example 1, although the weight average molecular weight of the component (A) is out of the range of the present invention, the breaking strength and the heat fusion strength are inferior to, for example, Example 1. . (2) In Comparative Examples 2 and 3, the ratios of the components (a) and (b) are out of the range of the present invention. It is clear that the moldability is inferior to those of Examples 6 and 7, which are close to these compounding ratios. (3) In Comparative Examples 4 and 5, in which the α-olefin unit, the melt flow rate or the maximum melting peak temperature of the component (d) does not correspond to the present invention, for example, as compared with Examples 1 to 3, tensile strength and heat fusion Poor strength and deformability, and poor bleed. (4) Comparative Example 6, which lacks the component (c), is inferior in bleed and low in tensile strength and heat fusion strength as compared with Examples 1 to 5. (5) Comparative Example 7 lacking the component (d) is inferior in heat fusion strength to Example 8 which is an example in which the amount of the component (d) is small. (6) Comparative Example 8 in which the component (d) is excessively added,
(D) The hardness is higher than that of Example 9 in which the amount of the component is large. From the above, it was found that good results were obtained in all aspects of hardness, tensile strength, heat-sealing strength, moldability (especially deformable extrusion moldability) and bleed only by the specific structure of the present invention.

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

Industrial Applicability The thermoplastic elastomer composition of the present invention is excellent in flexibility, mechanical strength, heat-sealing strength and profile extrusion processability, and gives a molded product with no stickiness and little bleed. Can be. Although this thermoplastic elastomer composition can be used for various applications, it is particularly excellent in profile extrusion processability and heat-sealing strength, so it can be used for electric refrigerator gaskets, various gaskets for building materials, molding materials for automobiles, etc. It is suitable for.

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[Procedure amendment]

[Submission date] June 4, 1999 (1999.6.4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Added

[Correction contents]

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing a die shape of a die used for evaluation of profile extrusion moldability in an example.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/18 C08L 23/18

Claims (4)

[Claims] 1. The following (a), (b), (c) and (d)
A thermoplastic elastomer composition comprising the following four components: (A) A hydrogenated product of a block copolymer represented by the following general formula (1) or (2), wherein the weight average molecular weight is 100,000 to 450,000, and the polymer block (A) is the copolymer. When the proportion of which is 10 to 50% by weight: 30 to 70% by weight (however, the total amount of the component (a) and the component (b) is 100% by weight
A- (BA) n (1) (2) (AB) n (2) (where A is a polymer block composed of vinyl aromatic hydrocarbon units, and B is (B) a polymer block comprising a conjugated diene unit, wherein n is an integer of 1 to 5) (b) Softener for hydrocarbon rubber: 70 to 30% by weight (c) Melt flow rate (MFR) is 0.01 -100 g / 10 min propylene-based polymer: 3 to 50 parts by weight (provided that the total amount of component (a) and component (b) is 100 parts by weight, the same applies hereinafter). (D) Melt flow rate (MFR) ) Is 1 to 40 g / 10 min, the maximum melting peak temperature is 95 ° C. or less by differential scanning calorimetry (DSC), and the density is 0.86 to 0. 91 g / cm ³ of a copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms: 3 to 80 parts by weight 2. The block copolymer of component (a) is at least one selected from the group consisting of a styrene-butadiene block copolymer, a styrene-isoprene block copolymer, and a styrene-butadiene / isoprene block copolymer. The thermoplastic elastomer composition according to claim 1, which is a block copolymer. 3. The thermoplastic elastomer composition according to claim 1, wherein the propylene polymer as the component (c) is a propylene homopolymer or a propylene-ethylene copolymer. 4. The α-olefin constituting the ethylene-α-olefin copolymer (d) is at least one α-olefin selected from the group consisting of butene-1, hexene-1, and octene-1. The thermoplastic elastomer composition according to any one of claims 1 to 3.