JPH09316287A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded product excellent in flexibility, mechanical strengths and rubber elasticity together with transparency. SOLUTION: This thermoplastic elastomer composition comprises (1) 100 pts.wt. of a hydrogenated block copolymer obtained by hydrogenating a block copolymer, having two or more of polymer blocks A comprising a vinyl aromatic compound and one or more of polymer blocks B comprising a conjugated diene compound, and containing 5-45wt.% of the vinyl aromatic compound and having 50000-150000 number average molecular weight, (2) 5-100 pts.wt. of an olefin-based copolymer comprising ethylene unit (I) and a >=4C α-olefin unit (II) in a units (I)/(II) ratio of 55/45 to 99/1 and (3) 10-200 pts.wt. of a plasticizer, and has <=10% haze value of a sheet when formed into the sheet having 2mm thickness.

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 which is excellent in transparency and gives a molded article excellent in flexibility, mechanical strength and rubber elasticity.

[0002]

2. Description of the Related Art In recent years, thermoplastic elastomer compositions have
It does not require a vulcanization process and can be molded in the same way as thermoplastics, so it can be used for automobile parts, home appliance parts,
It is used in a wide range of fields such as toys, sporting goods, and daily necessities.

[0003] Among such thermoplastic elastomer compositions, a vinyl aromatic compound-
Several proposals have been made regarding thermoplastic elastomer compositions using hydrogenated conjugated diene compound block copolymers (hereinafter sometimes referred to as block copolymer hydrogenated products). For example, a thermoplastic elastomer composition obtained by blending a hydrogenated block copolymer with a hydrocarbon oil and an olefin polymer is disclosed in JP-A-50-14742, JP-A-58-206644 and the like. ing.

[0004]

However, molded articles obtained from these thermoplastic elastomer compositions are excellent in flexibility and mechanical strength but inferior in transparency.
Its use is limited.

The present invention has been made in view of the above problems of the prior art, and provides a thermoplastic elastomer composition which is excellent in transparency and gives a molded article excellent in flexibility and mechanical strength. The challenge is to provide.

[0006]

According to the present invention, the above-mentioned problems are (a) two or more polymer blocks A made of a vinyl aromatic compound and one polymer block B made of a conjugated diene compound. A hydrogenated block copolymer obtained by hydrogenating a block copolymer having 1 or more of them, wherein the vinyl aromatic compound content is 5 to 45% by weight, and the number average molecular weight is 50,000 to 150,000. 100 parts by weight of hydrogenated block copolymer, (b) ethylene unit (I) and α-olefin unit (II) having 4 or more carbon atoms, the molar ratio of both ethylene unit (I) / carbon number 4 The above α-olefin unit (II) = 55/45 to 99
5 to 100 parts by weight of an olefinic copolymer having a ratio of 1/1 and (c) 10 to 200 parts by weight of a plasticizer, and a thickness of 2
When formed into a sheet of mm, the haze value of the sheet is 1
It is solved by providing a thermoplastic elastomer composition characterized by being 0% or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrogenated block copolymer (a) constituting the thermoplastic elastomer composition of the present invention comprises two or more polymer blocks A comprising a vinyl aromatic compound in the molecule, and a conjugated diene. A hydrogenated block copolymer obtained by hydrogenating a block copolymer having at least one polymer block B composed of a compound, for example, (AB)
_n- A (n represents an integer of 1 to 10), (AB) _m- X
(X represents a residue of a coupling agent, m represents an integer of 2 to 15) and the like. Hydrogenated block copolymer obtained by hydrogenating a vinyl aromatic compound-conjugated diene compound block copolymer having a structure such as Examples thereof include polymers. In the hydrogenated block copolymer (a), the content of the vinyl aromatic compound must be 5 to 45% by weight, and 10 to 4
It is preferably 0% by weight. The content of the vinyl aromatic compound in the hydrogenated block copolymer (a) is 5% by weight.
When the content is less than 50%, the mechanical strength of the molded product obtained from the thermoplastic elastomer composition is not sufficient. On the other hand, when the content of the vinyl aromatic compound exceeds 45% by weight, it is obtained from the thermoplastic elastomer composition. The flexibility of the molded product decreases.

The number average molecular weight of the hydrogenated block copolymer (ii) needs to be 50,000 to 150,000. When the number average molecular weight of the hydrogenated block copolymer (a) is less than 50,000, the mechanical strength of the molded product obtained from the thermoplastic elastomer composition is insufficient, while the hydrogenated block copolymer (a) ) Has a number average molecular weight of 15
If it exceeds 0000, the transparency of the molded article obtained from the thermoplastic elastomer composition will decrease.

The vinyl aromatic compound constituting the polymer block A in the block copolymer before hydrogenation is, for example, styrene, α-methylstyrene, o, m- or p-methylstyrene, 1,3-dimethyl. Examples thereof include styrene, vinyl naphthalene, vinyl anthracene and the like.
Among them, styrene or α-methylstyrene is preferred. The vinyl aromatic compounds may be used alone or in combination of two or more.

The conjugated diene compound constituting the polymer block B in the block copolymer before hydrogenation is, for example, 1,3-butadiene, isoprene, 2,3
-Dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like. Among these, isoprene, 1,3-butadiene or a mixture thereof is preferable. The conjugated diene compounds may be used alone or in combination of two or more.

The structure of the polymer block B in the block copolymer before hydrogenation is not particularly limited, and the content of 1,2-bonds and 3,4-bonds is not particularly limited.
Further, the bonding mode of the polymer block A and the polymer block B in the hydrogenated block copolymer (a) may be linear, branched, or any combination thereof.

Further, the hydrogenated block copolymer (a) is
A functional group such as a carboxyl group, a hydroxyl group, an acid anhydride, an amino group, or an epoxy group may be contained in the molecular chain or at the molecular terminal as long as the gist of the present invention is not impaired.

The hydrogenated block copolymer (a) is, for example,
It can be produced by the following known anionic polymerization method. That is, a block copolymer is formed by sequentially polymerizing a vinyl aromatic compound and a conjugated diene compound in an inert organic solvent such as n-hexane or cyclohexane using an alkyllithium compound or the like as an initiator. Next, this block copolymer is hydrogenated in a known manner in an inert organic solvent in the presence of a hydrogenation catalyst to obtain a hydrogenated block copolymer (a). At this time, from the viewpoint of heat resistance and weather resistance, it is preferable to hydrogenate 70% or more of the carbon-carbon double bonds derived from the conjugated diene compound in the block copolymer before hydrogenation. The content of carbon-carbon double bonds in the polymer block B in the hydrogenated block copolymer (a) can be measured by iodine value measurement, infrared spectrophotometer, nuclear magnetic resonance or the like.

Next, the olefin-based copolymer (b) constituting the thermoplastic elastomer composition of the present invention will be described. The olefin copolymer (b) is composed of an ethylene unit (I) and an α-olefin unit (II) having 4 or more carbon atoms, and the molar ratio of both is ethylene unit (I) / carbon number of 4 or more. Α-olefin unit (II) of
Polymers of 55/45 to 99/1 are used. If the molar ratio of the ethylene unit (I) to the α-olefin unit (II) having 4 or more carbon atoms is out of the above range, the phase of the olefin copolymer (b) and the hydrogenated block copolymer (a) will be changed. Since the solubility is poor and the molding processability of the thermoplastic elastomer composition is impaired, a molded article having excellent transparency and flexibility and mechanical strength cannot be obtained. Ethylene unit (I)
And the molar ratio of the α-olefin unit (II) having 4 or more carbon atoms is preferably ethylene unit (I) / α-olefin unit (II) having 4 or more carbon atoms = 65/35 to 99/1. .

Examples of the α-olefin unit (II) having 4 or more carbon atoms which composes the olefin copolymer (b) include, for example, 1-butene, 2-methyl-1-butene and 3-methyl-1-. Butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-
Examples include structural units derived from α-olefins such as octadecene. Among them, those having 4 to 12 carbon atoms
Structural units derived from an α-olefin of are preferred,
A structural unit derived from an α-olefin having 5 to 10 carbon atoms is more preferable, and a structural unit derived from 1-octene is particularly preferable. These may be used alone,
Two or more kinds may be used as a mixture.

Specific examples of the olefin-based copolymer (b) will be given below. For example, ethylene-butene random copolymer, ethylene-hexene random copolymer, ethylene-
Examples thereof include an octene random copolymer, an ethylene-decene random copolymer, and an ethylene-4-methylpentene random copolymer. Among these, an ethylene-butene random copolymer, an ethylene-hexene random copolymer, and an ethylene-octene random copolymer are preferred.

In the present invention, the olefin copolymer (b) is used.
For example, "Affinity (AFFINITY)", "Engage (EN
GAGE) "(both are trade names)," EXACT "(trade name) manufactured by Exxon Chemical Co., Ltd.,
"ESPREN" manufactured by Sumitomo Chemical Co., Ltd.
E) A commercially available product such as N series of SPO (trade name) ”can be used. These olefin-based copolymers (b) may be used alone or in combination of two or more.

The amount of the olefinic copolymer (B) used is
5 to 100 parts by weight of the hydrogenated block copolymer (a)
It is necessary to be 100 parts by weight, preferably 10 to 70 parts by weight. Olefin-based copolymer (b)
When less than 5 parts by weight is used with respect to 100 parts by weight of the hydrogenated block copolymer (a), the molding processability of the thermoplastic elastomer composition is poor, and the molded product obtained from the composition is poor. The problem arises that the mechanical strength is insufficient. On the other hand, when the amount of the olefin-based copolymer (b) used exceeds 100 parts by weight with respect to 100 parts by weight of the hydrogenated block copolymer (a), the rubber of the molded product obtained from the thermoplastic elastomer composition The elasticity is insufficient, which is not preferable.

As the plasticizer (c) constituting the thermoplastic elastomer composition of the present invention, known ones can be used without particular limitation, and examples thereof include paraffin type, naphthene type, aromatic type and liquid paraffin. Hydrocarbon oils; vegetable oils such as peanut oil and rosin; phosphoric acid esters; chlorinated paraffins; silicone oils; liquid polyisoprene or hydrogenated products thereof, liquid polybutadiene, liquid polyisobutylene and other liquid polymers having plasticizing ability or these. Modified products of the above can be used.

The amount of the plasticizer (c) used is required to be 10 to 200 parts by weight, preferably 20 to 150 parts by weight, based on 100 parts by weight of the hydrogenated block copolymer (a). . When the amount of the plasticizer (c) used is less than 10 parts by weight based on 100 parts by weight of the hydrogenated block copolymer (a), the thermoplastic elastomer composition obtained has poor moldability, while the plasticizer ( When the amount of (c) used exceeds 200 parts by weight relative to 100 parts by weight of the hydrogenated block copolymer (a), the molded product obtained from the thermoplastic elastomer composition has reduced mechanical strength and oil resistance, and has a surface The problem of increased tackiness arises.

The thermoplastic elastomer composition of the present invention comprises
If necessary, a filler can be added as long as it does not impair the gist of the present invention. Examples of such a filler include calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, magnesium carbonate, glass fiber, and carbon fiber.

Further, in the thermoplastic elastomer composition of the present invention, within a range that does not impair the gist of the present invention, various polyethylenes, various polypropylenes, olefin copolymers such as ethylene-propylene random copolymers (b). Polyolefin resin different from: polystyrene, poly α
-Methylstyrene, high impact polystyrene, AB
S-based resins such as S; polyethylene terephthalate;
Polyester resin such as polybutylene terephthalate;
A thermoplastic resin such as a polyamide resin such as nylon-6, nylon-66, and nylon-12 may be added.
Further, it is possible to add a heat stabilizer, an antioxidant, a light stabilizer, a colorant, a flame retardant, a tackifier, an antistatic agent, a foaming agent and the like.

As the method for producing the thermoplastic elastomer composition of the present invention, conventionally known methods can be used without any particular limitation. To obtain a homogeneous composition, a single-screw extruder, a twin-screw extruder, a Banbury are used. Mixer, brabender,
It is preferable to knead each component in a heated and molten state using a kneader such as an open roll or a kneader. Before melt-kneading, each component is dry-blended in advance using a mixer such as a Hensyl mixer or a tumbler,
A homogeneous thermoplastic elastomer composition can be obtained by melt-kneading the mixture.

The thermoplastic elastomer composition of the present invention comprises:
For example, it can be processed into a molded product using a conventionally known method such as extrusion molding, injection molding, hollow molding, compression molding, and calendar molding.

The thermoplastic elastomer composition of the present invention comprises
Excellent moldability, transparency, flexibility,
It has the feature of giving a molded product excellent in mechanical strength and rubber elasticity. Among them, the transparency is very excellent, when the sheet has a thickness of 2 mm, the haze value of the sheet is 10% or less. Further, a molded product obtained from the thermoplastic elastomer composition of the present invention is JI
The permanent elongation defined by S-K6301 is 10% or less, and the rubber elasticity is very excellent.

The thermoplastic elastomer composition of the present invention comprises:
For example, it is formed into a sheet, a film, or formed into a multilayer with another sheet or film, and is used for a sheet or a film such as packaging of daily sundries, packaging of industrial materials, packaging of foods and the like. Also used for hoses, tubes, belts, etc .;
Footwear for sports shoes, fashion sandals, etc .; for household appliances such as TVs, stereo cleaners, etc .; packing for refrigerator doors, sealing for building doors, window frames, bumper parts, body panels, etc. Daily necessities for interior / exterior parts; medical supplies such as medical syringe gaskets, catheter tubes, infusion bags, etc .; various grips for scissors, drivers, toothbrushes, skis, etc .; stationery such as pen grips; water glasses, snorkels, etc. Used in a wide range of applications such as leisure goods, toys, and industrial goods.

[0027]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. In these examples and comparative examples,
The transparency, mechanical strength and rubber elasticity of the molded product obtained from the thermoplastic elastomer composition were evaluated by the methods described below.

A) Transparency According to the method defined in JIS-K7105, the haze value of a sheet having a thickness of 2 mm was measured. b) Mechanical strength A dumbbell-shaped test piece specified in JIS-3 is punched out from a sheet having a thickness of 2 mm, and the test piece is used to JIS.
-Tensile speed 50 according to the method specified in K6301.
Tensile test is performed at cm / min and breaking strength (kg / cm
² ) was measured and used as an index of mechanical strength. c) Rubber elasticity A dumbbell-shaped test piece specified in JIS-1 is punched out from a sheet having a thickness of 2 mm, and the test piece is used to JIS.
-Tensile speed 50 according to the method specified in K6301.
A tensile test was performed at cm / min, and the permanent elongation (%) at 100% elongation was measured and used as an index of rubber elasticity.

Further, in the following Examples and Comparative Examples, the following were used as the hydrogenated block copolymer, the olefinic copolymer and the plasticizer, respectively. Hydrogenated block copolymer A -1) "Septon 4033" (trade name, Kuraray Co., Ltd.)
Made) [Styrene content: 30%, number average molecular weight: 100,000, hydrogenation rate: 98% or more] B-2) "Septon 8007" (trade name, Kuraray Co., Ltd.)
Manufactured) [styrene content: 29%, number average molecular weight: 85,000,
Hydrogenation rate: 98% or more] a-3) "Septon 4055" (trade name, Kuraray Co., Ltd.)
Made) [styrene content: 30%, number average molecular weight: 200,000, hydrogenation rate: 98% or more] olefin copolymer b-1) "AFFINITY PL-1880" (trade name,
(Made by Dow Chemical Co.) [Molar ratio of ethylene unit / 1-octene unit = 96.7 / 3.3] b-2) "ENGAGE EG-8200" (trade name, manufactured by Dow Chemical Co.) [Ethylene unit / 1-Octene unit molar ratio = 92.2 / 7.8] b-3) "Mitsubishi Polyethylene-LL UF420" (trade name,
Mitsubishi Chemical Co., Ltd.) [Ethylene unit 100%] b-4) "Mitsubishi Polypro MA3" (trade name, Mitsubishi Chemical Co., Ltd.) [Propylene unit 100%] Plasticizer c-1) "Diana Process Oil PW −380 ”(trade name, manufactured by Idemitsu Kosan Co., Ltd.)

Examples 1 to 8 and Comparative Examples 1 to 3 Using a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., TEM-35B), according to the formulation shown in Table 1, each component was heated to 230 ° C.
To obtain a pellet-shaped thermoplastic elastomer composition. The obtained pellets were heated at a cylinder temperature of 230.
And a thickness of 2 mm by an injection molding machine (IS-55EPN manufactured by Toshiba Machine Co., Ltd.) set at 60 ° C. and a mold temperature of 60 ° C.
Was prepared. Using the obtained sheet, the transparency, mechanical strength and rubber elasticity were evaluated according to the methods described above. The results are shown in Table 1.

[0031]

[Table 1]

As is apparent from Table 1, the molded articles obtained from the thermoplastic elastomer compositions of Examples 1 to 8 are excellent in transparency and have sufficiently high mechanical strength. Also, J
The permanent elongation specified in IS-K6301 is 10% or less, and the rubber elasticity is excellent.

On the other hand, the molded product obtained from the thermoplastic elastomer composition of Comparative Example 1 exhibits sufficient physical properties in mechanical strength and rubber elasticity, but has low transparency.
Further, although the molded products obtained from the thermoplastic elastomer compositions of Comparative Example 2 and Comparative Example 3 have excellent mechanical strength,
Poor transparency and poor rubber elasticity.

[0034]

Industrial Applicability According to the present invention, there is provided a thermoplastic elastomer composition which is excellent in transparency and gives a molded article excellent in flexibility, mechanical strength and rubber elasticity. Molded articles obtained from the thermoplastic elastomer composition of the present invention are useful in fields such as daily necessities, industrial goods, food containers, packaging materials, etc., and are particularly suitable for fields requiring transparency and rubber elasticity, and parts. Can be used.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location C08L 23/08 LCN C08L 23/08 LCN (72) Inventor Mitsuo Masuda Higashi, Kamisu-cho, Kashima-gun, Ibaraki Prefecture 36 Wada, Kuraray Co., Ltd. (72) Masao Ishii Inventor Masao Ishii 36, Higashiwada, Kamisu Town, Kashima-gun, Ibaraki Kuraray Co., Ltd.

Claims (2)

[Claims] 1. Water obtained by hydrogenating a block copolymer having (a) two or more polymer blocks A made of a vinyl aromatic compound and one or more polymer blocks B made of a conjugated diene compound. 100 parts by weight of a hydrogenated block copolymer having a vinyl aromatic compound content of 5 to 45% by weight and a number average molecular weight of 50,000 to 150,000, and (b) an ethylene unit. (I) and an α-olefin unit having 4 or more carbon atoms (I
I) and the molar ratio of both is ethylene unit (I) / α-olefin unit (II) having 4 or more carbon atoms = 55/45
5 to 100 parts by weight of 99/1 olefinic copolymer, and (c) 10 to 200 parts by weight of a plasticizer,
A thermoplastic elastomer composition, which has a haze value of 10% or less when formed into a sheet having a thickness of 2 mm. 2. A molded article obtained from the thermoplastic elastomer composition according to claim 1.