JP2003003039A - Method for producing thermoplastic elastomer composition - Google Patents

Abstract

(57) [SUMMARY] [PROBLEMS] To provide excellent flexibility, rubber elasticity, rubber elasticity at high temperature, low compression set at high temperature, high temperature creep performance, mechanical strength, oil resistance, solvent resistance, heat resistance Providing a simple method for producing a thermoplastic elastomer composition capable of producing a molded article having excellent weather resistance and the like. SOLUTION: Vinyl aromatic compound-based polymer block
Hydrogenated block copolymer (a) having a Mn of 200,000 or more comprising a conjugated diene compound polymer block, a non-aromatic rubber softener (b), and a peroxide crosslinked olefin having a density of 0.94 g / cm ³ or more System resin (c), peroxide-decomposable olefin resin (d), organic peroxide (e) and crosslinking aid (f); (a) 100 parts by weight of (b) Is 50 to 250 parts and the amount of (c) is 2.5 to 50 parts,
A method for producing a thermoplastic elastomer composition by melt-kneading a mixture in which the blending amount of (d) is 0.8 to 8 times that of (c) and heating and kneading in one step and then dynamically cross-linking.

Description

Detailed Description of the Invention TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for producing a thermoplastic elastomer composition. More specifically, the present invention provides a simple melt-kneading process, which is excellent in flexibility, rubber elasticity, particularly rubber elasticity at high temperature and has a small compression set, and further high temperature creep performance, mechanical strength, and oil resistance. The present invention relates to a method for producing a thermoplastic elastomer composition having excellent properties, solvent resistance, heat resistance, and weather resistance. The thermoplastic elastomer composition obtained by the method of the present invention can be utilized as a material for various molded products by taking advantage of its excellent properties.

[0002]

2. Description of the Related Art Thermoplastic elastomers do not require a vulcanization step and can be molded in the same manner as thermoplastic resins, so in recent years, automobile parts, home electric appliance parts, wire coatings, medical parts, footwear, and sundries It is used in a wide range of fields such as. Among such thermoplastic elastomers, polystyrene-
Polybutadiene-polystyrene block copolymer (SB
S), polystyrene-polyisoprene-polystyrene block copolymer (SIS), and styrene-based thermoplastic elastomers represented by hydrogenated products thereof are widely used because they are inexpensive and have excellent hydrolysis resistance.

Hydrogenated products of polystyrene-polybutadiene-polystyrene block copolymers and polystyrene-
A hydrogenated product of a block copolymer having a vinyl aromatic compound polymer block and a conjugated diene compound polymer block, represented by a hydrogenated product of a polyisoprene-polystyrene block copolymer, is a vinyl aromatic compound polymer block. Although the block copolymer having a conjugated diene compound polymer block has improved problems such as heat resistance and weather resistance, it is inferior in rubber elasticity at high temperature and has a large compression set at high temperature.

In order to improve the above points, Japanese Patent Laid-Open No. 59-62.
36 and JP-A-8-225713 describe a hydrogenated product of a block copolymer comprising such a vinyl aromatic compound polymer block-conjugated diene compound polymer block as a) peroxide-decomposable olefin resin. When,
b) A method of partially cross-linking with an organic peroxide in combination with a peroxide cross-linking olefin copolymer rubber or a peroxide cross-linking olefin resin has been proposed.

More specifically, the above-mentioned JP-A-59-623.
No. 6 discloses (a-1) 100 parts by mass of hydrogenated product of a block copolymer having two or more vinyl aromatic compound polymer blocks and one or more conjugated diene compound polymer blocks, (a-2). 20 to 150 parts by mass of peroxide cross-linking olefin copolymer rubber, (a-3) 0 to 50 parts by mass of peroxide non-crosslinking hydrocarbon rubber-like substance, (a-4) softening for non-aromatic rubber 80 to 300 parts by mass of the agent,
(A-5) Peroxide decomposition type olefin resin 30
To 400 parts by mass, and (A-6) inorganic filler 0 to 90
First, 0 parts by mass of each component is dynamically crosslinked by heat-treating at least the entire amount of (a-2) among the components other than (a-1) in the presence of an organic peroxide, and then performing the dynamic crosslinking. There is described a method for producing an elastomeric composition by mixing a product with the component (A-1) and the remaining components. And, in this publication, it is explained that the mechanical strength of the elastomeric composition is significantly reduced when the multi-step partial crosslinking-compounding step described above is not adopted.

Further, JP-A-8-225713 discloses a block copolymer having two or more (ro-1) vinyl aromatic compound polymer blocks and one or more conjugated diene compound polymer blocks and / or a block copolymer thereof. Hydrogenated product 10
0 parts by mass, (B-2) softener for non-aromatic rubber 40 to 3
00 parts by mass, (b-3) peroxide cross-linking olefin resin and / or copolymer rubber 1.0 containing the same
To 100 parts by mass, (b-4) peroxide-decomposable olefin resin and / or a copolymer containing the same.
In the method for producing a thermoplastic elastomer composition containing 150 parts by mass, the component (b-1) and the component (b-2),
At least a part of the component (ro-3) and the component (ro-3)
Part of 4) is heat treated in the presence of organic peroxide to crosslink, and then the crosslinked product and the balance of component (b-4) or the balance of component (b-3) and component (b-4). And a method for producing a thermoplastic elastomer resin composition in which is added. Then, in this publication, the composition dynamically crosslinked in the presence of organic peroxide and the component (B-4) to be blended later are compatible with each other and microdispersed in the composition,
Processing characteristics of the resulting thermoplastic elastomer resin composition,
It is explained that fluidity and mechanical strength are improved.

However, in the methods described in the above-mentioned two publications, each component cannot be dynamically crosslinked at a final blending ratio at once, and some of the components are dynamically crosslinked. Since it is necessary to mix the remaining components later, the manufacturing process of the thermoplastic elastomer resin composition is very complicated, and the rubber elasticity is still insufficient especially at high temperatures.

[0008]

The object of the present invention is to provide a hydrogenated product of a block copolymer having a vinyl aromatic compound polymer block and a conjugated diene compound polymer block, a softening agent for a non-aromatic rubber, and a peroxide. In a thermoplastic elastomer composition obtained by dynamically crosslinking a mixture containing an oxide crosslinkable olefin resin and a peroxide decomposable olefin resin in the presence of an organic peroxide,
A dynamic crosslinked thermoplastic elastomer composition having excellent physical properties is obtained by a simple heat kneading step of one step without requiring a multistep partial crosslinking-compounding step as in the prior art described in the above publication. It is to provide a method of manufacturing. In particular, in a simple heat kneading step, it is excellent in flexibility, rubber elasticity, especially rubber elasticity at high temperature and has a small compression set, high temperature creep performance, mechanical strength, oil resistance, solvent resistance. It is an object of the present invention to provide a method for producing a dynamically crosslinked thermoplastic elastomer composition capable of producing a molded article having excellent properties, heat resistance, weather resistance and surface characteristics.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a hydrogenated product of a block copolymer having a vinyl aromatic compound polymer block and a conjugated diene compound block and a non-aromatic system. In producing a thermoplastic elastomer composition by dynamically crosslinking a mixture containing a softening agent for rubber, a peroxide-crosslinking olefin-based resin, and a peroxide-decomposing olefin-based resin in the presence of an organic peroxide, a vinyl aromatic As a hydrogenated product of a block copolymer having a compound polymer block and a conjugated diene compound polymer block, one having a molecular weight in a specific range is used, and one having a specific density is used as a peroxide cross-linking olefin resin. In addition, hydrogenated block copolymer, softener for non-aromatic rubber, per If the compounding amounts of the oxidant crosslinkable olefinic resin and the peroxide decomposing olefinic resin are set within a specific range, the multi-step dynamic crosslinking-compounding step as in the prior art described in the above two publications becomes unnecessary. It was found that a dynamically crosslinked thermoplastic elastomer composition having good physical properties can be obtained in a single heating and kneading step. In particular, the dynamically crosslinked thermoplastic elastomer composition obtained by such a one-step heating and kneading step and the molded article obtained therefrom have excellent flexibility, and also have excellent rubber elasticity, particularly rubber elasticity at high temperature. Even if it is compressed at high temperature for a long time, the compression set is small, and in addition, it has excellent properties such as high temperature creep performance, mechanical strength, oil resistance, solvent resistance, heat resistance, and weather resistance. There is no bleed-out of softener to
It has been found to have a good appearance. Further, the inventors of the present invention preferably use the conjugated diene polymer block as a hydrogenated product of the block copolymer, which is a polymer block composed of 1,3-butadiene and isoprene. And it is preferable to use the compounding amount of the cross-linking aid in a specific range, and it is found that a softening agent for a non-aromatic rubber having a specific kinematic viscosity is preferably used, and based on those findings The present invention has been completed.

That is, the present invention contains (1) (i) at least one polymer block A mainly containing a vinyl aromatic compound and at least one polymer block B mainly containing a conjugated diene compound. Hydrogenated block copolymer (a) having a number average molecular weight of 200,000 or more obtained by hydrogenating a block copolymer, a softening agent for non-aromatic rubber (b),
A peroxide cross-linking olefin resin (c) having a density of 0.94 g / cm ³ or more, a peroxide decomposing olefin resin (d), an organic peroxide (e), and a cross-linking aid (f); And (ii) the compounding amount of the non-aromatic softening agent for rubber (b) is 50 to 250 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (a); (iii) peroxide The amount of the crosslinked olefin resin (c) added is 100% of the hydrogenated block copolymer (a).
2.5 to 50 parts by weight with respect to parts by weight; and
(Iv) The amount of the peroxide-decomposable olefin-based resin (d) is 0.8 to 8 times the amount of the peroxide-crosslinked olefin-based resin (c); A method for producing a thermoplastic elastomer composition, which comprises melt-kneading under heating to dynamically crosslink.

According to the present invention, (2) the polymer block B containing the conjugated diene compound as a main component in the hydrogenated block copolymer (a) is a polymer block composed of 1,3-butadiene and isoprene. (3) The method for producing a thermoplastic elastomer composition according to (1); (3) The amount of the organic peroxide (e) added is 0.3 to 1. The heat of (1) or (2), which is 5 parts by mass, and the amount of the crosslinking aid (f) added is 0.5 to 3.0 times by mass the amount of the organic peroxide (e) compounded. Method for producing a plastic elastomer composition; and (4) Kinematic viscosity (Bv) (mm ² / s) of the non-aromatic softening agent for rubber (b) at 40 ° C
Is a method for producing the thermoplastic elastomer composition according to any one of (1) to (3) above, which satisfies the following formula:

[0012]

## EQU2 ## Bv (mm ² / s) ≧ 3 × 10 ⁷ / Mna [In the above formula, Bv is 4 of the non-aromatic rubber softening agent (b)]
Kinematic viscosity at 0 ° C. and Mna represent the number average molecular weight of the hydrogenated block copolymer (a). ]; Is included as a preferable aspect.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. Hydrogenated block copolymer (a) used in the present invention
Is a hydrogenated product obtained by hydrogenating a block copolymer containing at least one polymer block A mainly containing a vinyl aromatic compound and at least one polymer block B mainly containing a conjugated diene compound. It is a block copolymer. In the hydrogenated block copolymer (a), examples of the vinyl aromatic compound constituting the polymer block A include styrene, α-methylstyrene, o-methylstyrene,
m-methylstyrene, p-methylstyrene, pt-butylstyrene, 2,4-dimethylstyrene, 2,4,6
-Trimethylstyrene, monofluorostyrene, monochlorostyrene, dichlorostyrene, vinylnaphthalene,
Examples of the polymer block A include vinyl anthracene and the like, and the polymer block A is one or two of these vinyl aromatic compounds.
It can be formed from more than one species. Among them, the polymer block A is preferably formed of styrene. The polymer block A may be an unsaturated monomer other than a vinyl aromatic compound (for example, 1-butene, pentene, hexene, 1,3-butadiene, isoprene) as long as it does not hinder the objects and effects of the present invention. ,
It may have a small amount (preferably 10% by mass or less of the polymer block A) of one or more structural units derived from methyl vinyl ether, methyl methacrylate, vinyl acetate, etc.).

Examples of the conjugated diene compound constituting the polymer block B in the hydrogenated block copolymer (a) used in the present invention include 1,3-butadiene, isoprene and 2,3-dimethyl-1, 3-butadiene, 1,
3-pentadiene, 1,3-hexadiene and the like can be mentioned, and the polymer block B can be formed of one kind or two or more kinds of these conjugated diene compounds. Among them, the polymer block B is 1,3-
It is particularly preferred that it is formed from both butadiene and isoprene. If polymer block B is formed from both 1,3-butadiene and isoprene,
The molded article obtained from the thermoplastic elastomer composition has no stickiness on the surface, and the polymer block B has 1,3
-The retention of the non-aromatic softening agent for rubber (b) in the hydrogenated block copolymer (a) is increased as compared with the case of comprising a butadiene homopolymer or an isoprene homopolymer,
Bleeding out of the non-aromatic softening agent for rubber (b) can be suppressed.

The bonding form of the conjugated diene compound in the polymer block B is not particularly limited. For example, in the case of 1,3-butadiene, 1,2-bond and / or 1,4
In the case of -bond, isoprene, 1,2-bond, 3,4-bond and / or 1,4-bond can be adopted, and any of these bond forms may be used. Of which
When the polymer block B is formed from both 1,3-butadiene and isoprene, it is particularly preferred that the sum of 3,4-bonds and 1,2-bonds is 5 to 70 mol%. Further, the polymer block B is a conjugated diene compound of two or more kinds (for example, 1,3-butadiene and isoprene).
In the case of being formed from, the bonding form thereof can be completely alternating, random, tapered, partially block-shaped, or a combination of two or more thereof.

In the polymer block B, some or all of the carbon-carbon double bonds based on the conjugated diene compound must be hydrogenated (hydrogenated). The hydrogenation rate is not particularly limited, but from the viewpoint of heat resistance and weather resistance, it is preferable that 85 mol% or more of the carbon-carbon double bond based on the conjugated diene compound be hydrogenated, and 90 mol% or more of water. It is more preferable that they are added. The hydrogenation rate (hydrogenation rate) is the content of the carbon-carbon double bond based on the conjugated diene compound in the polymer block B before and after hydrogenation, iodine value measurement, infrared spectrophotometer, ¹ H-N
It can be measured by an MR spectrum or the like and can be obtained from the measured value.

The polymer block B may be an unsaturated monomer other than the conjugated diene compound (for example, 1-butene, 1-pentene, 1-hexene, methyl, etc.) as long as it does not interfere with the objects and effects of the present invention. It may have a small amount (preferably 10% by mass or less of the polymer block B) of one or more structural units derived from vinyl ether, styrene, methyl methacrylate, vinyl acetate, etc.).

As long as the hydrogenated block copolymer (a) is a hydrogenated product of a block copolymer in which at least one polymer block A and at least one polymer block B are bonded, its weight is The binding mode of the united block is not limited,
It may be linear, branched, radial, or a combined form of two or more thereof combined. Among them, it is preferable that the polymer block A and the polymer block B have a linear bond form. For example, when the polymer block A is represented by A and the polymer block B is represented by B. To the hydrogenated product of the AB diblock copolymer, AB-
Hydrogenated product of triblock copolymer of A, Hydrogenated product of tetrablock copolymer of ABAB, ABABA
The hydrogenated product of the pentablock copolymer can be mentioned. Among them, the hydrogenated product of the ABA triblock copolymer is preferably used from the viewpoints of easiness of production of the block copolymer, flexibility, rubber elasticity and the like.

The content of the structural unit derived from the vinyl aromatic compound in the hydrogenated block copolymer (a) is in the range of 10 to 65 mass% from the viewpoint of mechanical strength and flexibility of the thermoplastic elastomer composition. Preferably 15
More preferably, it is within the range of from 35 to 35 mass%. The content of the structural unit derived from the vinyl aromatic compound in the hydrogenated block copolymer (a) can be determined by ¹ H-NMR spectrum or the like.

The hydrogenated block copolymer (a) is
The number average molecular weight after hydrogenation is required to be 200,000 or more, more preferably 250,000 or more. When the number average molecular weight of the hydrogenated block copolymer (a) is less than 200,000, the rubber elasticity at high temperature of the thermoplastic elastomer composition produced by the method of the present invention is lowered. The upper limit of the number average molecular weight of the hydrogenated block copolymer (a) is not particularly limited, but it is preferably 500,000 or less from the viewpoint of processability of the thermoplastic elastomer composition produced by the method of the present invention. The number average molecular weight referred to in the present specification is a polystyrene-equivalent molecular weight determined by gel permeation chromatography (GPC) measurement.

As long as the hydrogenated block copolymer (a) does not impair the gist of the present invention, the hydrogenated block copolymer (a) may be used in the molecular chain and / or
Alternatively, one or two functional groups such as a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group and an epoxy group may be attached to the terminal of the molecule.
It may have more than one species.

The method for producing the hydrogenated block copolymer (a) used in the present invention is not particularly limited, and the hydrogenated block copolymer (a) can be produced, for example, by the following conventionally known anionic polymerization method. That is, a vinyl aromatic compound and a conjugated diene compound are sequentially polymerized in a polymerization reaction-inert organic solvent such as n-hexane and cyclohexane using an alkyllithium compound as an initiator, or block copolymerization is performed by a method such as coupling. Form a coalesce. Then, the obtained block copolymer is hydrogenated in the presence of a hydrogenation catalyst in an inert organic solvent according to a known method to produce a hydrogenated block copolymer (a).

As the non-aromatic softening agent for rubber (b) used in the present invention, any conventionally known non-aromatic softening agent for rubber can be used, and among them, non-aromatic minerals. Oils or liquid or low molecular weight synthetic softeners are suitable. The non-aromatic softening agent for rubber (b) may be used alone or in combination of two or more kinds. Generally, a process oil or a softener for a mineral oil type rubber called an extender oil, which is used for softening, increasing the volume and improving the processability of a rubber, is a combination of an aromatic ring, a naphthene ring and a paraffin chain. A mixture of
Of the total number of carbon atoms, those in which the number of carbon atoms in the paraffin chain accounts for 50% or more are called paraffinic. Many are called aromatic. In the present invention, among the above-mentioned process oils, paraffin-based process oil and naphthene-based process oil can be used. In addition to them, white oil, mineral oil, low molecular weight copolymer (oligomer) of ethylene and α-olefin, paraffin wax, liquid paraffin and the like can be used. Among these, in the present invention, paraffin-based process oil and / or naphthene-based process oil are preferably used as the non-aromatic rubber softening agent (b).

When an aromatic rubber softening agent such as an aromatic process oil is used instead of the non-aromatic rubber softening agent (b), the hydrogenated block copolymer (a) is used. The polymer block composed of the vinyl aromatic compound therein is attacked, and the physical properties of the thermoplastic elastomer composition, particularly mechanical strength and rubber elasticity cannot be improved.

Further, in the production method of the present invention, from the viewpoint of improving the heat resistance of the obtained thermoplastic elastomer composition, in particular, maintaining the rubber elasticity at high temperature, the softening agent for non-aromatic rubber (b ) At 40 ° C. (m
It is preferable that m ² / s) satisfies the following mathematical formula.

[0026]

## EQU3 ## Bv (mm ² / s) ≧ 3 × 10 ⁷ / Mna [In the above formula, Bv is 4 of the non-aromatic rubber softening agent (b)]
Kinematic viscosity at 0 ° C. and Mna represent the number average molecular weight of the hydrogenated block copolymer (a). ] The kinematic viscosity (mm ² / s) of the non-aromatic softening agent for rubber in the present specification at 40 ° C. means a temperature of 40 by using a B-type viscometer.
It is the value of the quotient obtained by dividing the kinematic viscosity measured at ° C by the density of the non-aromatic rubber softening agent (b) at 40 ° C.

The compounding amount of the non-aromatic softening agent for rubber (b) must be 50 to 250 parts by mass, preferably 80 parts by mass, relative to 100 parts by mass of the hydrogenated block copolymer (a). To 200 parts by mass. The blending amount of the non-aromatic rubber softening agent (b) is such that the hydrogenated block copolymer (a) 1
When the amount is less than 50 parts by mass with respect to 00 parts by mass, the flexibility of the thermoplastic elastomer composition obtained by the method of the present invention becomes poor, and the molding processability decreases, while 250 parts by mass. If it exceeds the range, the mechanical strength of the molded article made of the thermoplastic elastomer composition obtained by the method of the present invention is insufficient, and further bleeding out of the softening agent (b) for non-aromatic rubber occurs.

The peroxide-crosslinkable olefin resin (c) used in the present invention means an olefin resin which is crosslinked by heat treatment in the presence of peroxide to increase its molecular weight. Examples of the peroxide-crosslinking olefin resin (c) include polyethylene, copolymers of ethylene with a small amount of propylene, 1-hexene, 1-octene, and the like, and one or more of these may be used. Can be used. Among them, polyethylene is preferably used from the viewpoint of exhibiting rubber elasticity at high temperature.

The peroxide-crosslinkable olefin resin (c) used in the present invention has a density must be at 0.94 g / cm ³ or more, preferably 0.95 g / cm ³ or more. When the density of the peroxide-crosslinking olefin resin (c) is less than 0.94 g / cm ³ ,
The rubber elasticity of the thermoplastic elastomer composition obtained by the method of the present invention is insufficient at a high temperature, particularly at a high temperature exceeding 100 ° C.

The MFR of the peroxide-crosslinking olefin resin (c) is 10 to 50 g / 10 minutes under the conditions of 190 ° C. and 21.2 N, which means that the fluidity of the obtained thermoplastic elastomer composition is high. Is preferable from the point of 2
It is more preferably 0 to 50 g / 10 minutes.

The amount of the peroxide-crosslinking olefin resin (c) to be added is 100% of the hydrogenated block copolymer (a).
It is necessary to be 2.5 to 50 parts by mass, preferably 5 to 45 parts by mass with respect to parts by mass. The amount of the peroxide-crosslinking olefin resin (c) is 2.5.
If it is less than 50 parts by mass, the rubber elasticity of the obtained thermoplastic elastomer composition at high temperature becomes insufficient and the compression set becomes large, while if it exceeds 50 parts by mass, the hardness of the obtained thermoplastic elastomer composition. Is too high, the flexibility is lost, and the bleed-out of the softening agent (b) for non-aromatic rubber becomes remarkable, which is not desirable.

The peroxide-decomposable olefin resin (d) used in the present invention is an olefin resin that is thermally decomposed by heat treatment in the presence of peroxide to reduce its molecular weight and increase its fluidity. Say. Examples of the peroxide-decomposable olefin resin (d) include, for example, isotactic polypropylene, a copolymer of propylene and a small amount of other α-olefin such as ethylene, 1-butene, 1-hexene, and 1-octene. And one or more of these can be used. Among them, a copolymer of propylene and a small amount of α-olefin is preferably used from the viewpoint that the rubber elasticity of the thermoplastic elastomer composition is good, and particularly a block type is more preferably used.

The amount of the peroxide-decomposable olefin resin (d) to be blended must be 0.8 to 8 times the amount of the peroxide-crosslinking olefin resin (c), and 1 to 5 is required. It is preferably mass times. When the amount of the peroxide-decomposable olefin resin (d) is less than 0.8 times the amount of the peroxide crosslinkable olefin resin (c), a molded article obtained from the thermoplastic elastomer composition, particularly The surface smoothness of the injection-molded product is lost, while when it exceeds 8 times by mass, the rubber elasticity of the resulting thermoplastic elastomer composition at high temperature is lost and the compression set becomes large.

In the present invention, the organic peroxide (e) is used together with the above components. As the organic peroxide (e), any organic peroxide having a crosslinking action under dynamic conditions may be used, and either aromatic peroxide or aliphatic peroxide can be used. Further, one kind of organic peroxide may be used, or two or more kinds of organic peroxide may be used. Specific examples of the organic peroxide (e) that can be used in the present invention include 2,5-dimethyl-2,5-
Di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t
-Butyl peroxybenzoate, dicumyl peroxide, diisopropyl benzohydroperoxide,
1,3-bis- (t-butylperoxyisopropyl)
Examples thereof include benzene and benzoyl peroxide, and one or more of these can be used. The amount of the organic peroxide (e) to be used can be arbitrarily selected, but in view of the effect of improving the rubber elasticity at high temperature and the fluidity of the thermoplastic elastomer composition obtained by the method of the present invention, the above-mentioned component (a) is used. ) To (d) is preferably 0.3 to 1.5 parts by mass, and more preferably 0.5 to 1.0 parts by mass, based on 100 parts by mass.

In the present invention, a crosslinking aid (f) is further used. A polyfunctional monomer is preferably used as the crosslinking aid (f), and specific examples thereof include vinyl polyfunctional monomers such as triallyl isocyanurate and divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and triethylene glycol. Examples thereof include acrylic polyfunctional monomers such as dimethacrylate. The amount of the cross-linking aid (f) to be added is not particularly limited, but in general, the organic peroxide (e)
It is particularly preferably 0.5 to 3.0 parts by mass with respect to 1 part by mass.

In the present invention, an inorganic filler may be used if necessary. By blending the inorganic filler, it is possible to improve some physical properties such as compression set of a molded article made of the thermoplastic elastomer composition obtained by the method of the present invention, and further reduce the cost by increasing the amount. it can. Examples of inorganic fillers that can be used include calcium carbonate, talc, magnesium hydroxide, mica, clay, barium sulfate, natural silicic acid, synthetic silicic acid, titanium oxide, and carbon black.
These 1 type (s) or 2 or more types can be used.

In the present invention, if necessary, poly α-
Reinforcing resin such as methylstyrene, non-hydrogenated block copolymer, flame retardant, antioxidant, heat stabilizer, ultraviolet absorber, light stabilizer, antistatic agent, release agent, foaming agent, pigment, dye, A whitening agent or the like can be used.

In the present invention, the components (a) to (f) described above are used.
And, optionally, a mixture containing other components is kneaded together in a heat-melted state in one step. As a result, a dynamically crosslinked thermoplastic elastomer composition having excellent properties can be produced by an extremely simple process. Here, the term "dynamic cross-linking" in the present specification means that a mixture containing the above-mentioned components (a) to (f) and optionally other components is kneaded in a heating and melting state while applying a shear stress from the outside. Means to crosslink. In the production method of the present invention, in producing the dynamically crosslinked thermoplastic elastomer composition, the kneading temperature is preferably selected from the range of 150 to 250 ° C. Among them, the first half of the kneading is performed at a temperature at which the half-life of the organic peroxide (e) is 1/2 or more of the total kneading time, and the second half of the kneading has the half-life of the organic peroxide (e) of 1 of the total kneading time. It is preferable to carry out kneading at a temperature of less than / 2 from the viewpoint that the obtained thermoplastic elastomer composition has good physical properties and molding processability. When the kneading is carried out in the first half of the kneading at a temperature at which the half-life of the organic peroxide (e) is less than 1/2 of the total kneading time, the hydrogenated block copolymer (a) and the peroxide-crosslinking olefin resin (c) Is not preferable because the crosslinking reaction proceeds before being finely dispersed in the composition, and the resulting thermoplastic elastomer composition tends to have deteriorated physical properties and moldability. In the present specification, the first half of kneading generally means the time from the start of kneading to about half of the total kneading time, and the latter half is the latter half of kneading.

In the production method of the present invention, the heating and melt-kneading in the above-mentioned one-step process is a method conventionally used for melt-kneading a thermoplastic polymer, for example, a single-screw extruder,
A twin-screw extruder, a Banbury mixer, a heating roll, a Brabender, a kneader such as various kneaders can be used to adopt a method of kneading each constituent component in a heat-melted state at once, and among them, From the viewpoint of temperature control during kneading, a method of performing melt kneading in a single stage using a single-screw extruder, a twin-screw extruder, or the like is preferably adopted because a dynamically crosslinked thermoplastic elastomer composition can be produced more easily. It

The thermoplastic elastomer composition obtained by the method of the present invention can be molded by various molding methods such as injection molding, press molding, extrusion molding, calender molding and blow molding. From the thermoplastic elastomer composition obtained by the method of the present invention, it is possible to obtain a molded article having excellent flexibility, mechanical strength and rubber elasticity, for example, a sheet, a film, a plate-like body, or a tube-shaped body, Applications for hoses, belts, tubes, etc .; Footwear applications for sports shoes, fashion sandals, etc .; Home appliance applications for TVs, stereos, vacuum cleaners, refrigerators, etc. Sealing packings for building doors and window frames; Bumper parts, It can be effectively used for a wide range of applications such as interior and exterior parts for automobiles such as body panels and weather strips; various grips for scissors, drivers, toothbrushes, ski poles and the like.

[0041]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. In the following examples, various physical properties (hardness, tensile strength, tensile elongation, compression set, oil resistance and surface condition) of molded articles obtained from the thermoplastic elastomer composition were measured or evaluated by the following methods. .

(1) Hardness: "Type A" hardness was measured according to JIS K-6253.

(2) Tensile strength and tensile elongation: Dumbbell No. 5 test pieces were punched out from the injection-molded sheets obtained in the following examples and subjected to a tensile test in accordance with JIS K-6251, and at the time of breaking. The strength and the elongation were measured and used as the tensile strength and the tensile elongation.

(3) Compression set: The injection-molded sheet obtained in the following example was punched into a circle having a diameter of 29 mm,
Six pieces are stacked and pressed at a temperature of 200 ° C. and a pressure of 2.9 MPa to prepare a test piece, and the test piece is used to JIS
According to K-6262, temperature 100 ℃ and 120 ℃
Then, compression was performed at a compression rate of 25% for 22 hours, the compression was released after 22 hours, and the compression set at that time was measured.

(4) Oil resistance: length × width × thickness = 40 mm × 20 mm × 2 m from the injection-molded sheets obtained in the following examples
A test piece of size m was punched out, and JIS K-6258 was used.
A No. 2 swelling oil was used to conduct an oil resistance test at 100 ° C. for 24 hours, and the mass increase rate after the oil resistance test with respect to the mass before the oil resistance test was determined as the mass swelling rate.

(5) Surface texture of molded product: The surface of the injection-molded sheet obtained in the following example was visually observed to be good (◯) when it had a smooth surface without roughness, and The case where the surface was rough was evaluated as defective (x).

The contents and abbreviations of the components used in the following examples are as follows. (1) Hydrogenated block copolymer (a): Blocked by anionic polymerization of a mixed monomer of styrene and isoprene / 1,3-butadiene in cyclohexane using s-butyllithium as a polymerization initiator. The copolymer was synthesized, and the obtained block copolymer was subjected to hydrogenation reaction in cyclohexane at 75 ° C. for 5 hours at 75 ° C. in a hydrogen pressure atmosphere of 0.8 MPa using a Ziegler catalyst. The hydrogenated block copolymer shown was obtained.

[0048]

[Table 1]

(2) Softener for non-aromatic rubber (b): (b) -1: "Diana Process P" manufactured by Idemitsu Kosan Co., Ltd.
W-380 "[paraffin-based process oil; kinematic viscosity =
381.6 mm ² / s (40 ° C.), pour point = −15 ° C.,
Ring analysis: CN = 27.0%, CP = 73.0%] (b) -2: “Diana Process P” manufactured by Idemitsu Kosan Co., Ltd.
W-90 ”[paraffin-based process oil; kinematic viscosity = 9
5.54 mm ² / s (40 ° C.), pour point = −15 ° C., ring analysis: CN = 29.0%, CP = 71.0%]

(3) Peroxide cross-linking olefin resin (c): (c) -1: "Novatech HJ" manufactured by Nippon Polychem Co., Ltd.
490 "[high-density polyethylene resin; MFR = 20 g /
10 minutes (190 ° C, 21.2N), density = 0.958g
/ Cm ³ ] (c) -2: "Novatech LJ" manufactured by Nippon Polychem Co., Ltd.
800 ”[low density polyethylene resin; MFR = 20 g /
10 minutes (190 ° C, 21.2N); density = 0.918g
/ Cm ³ ]

(4) Peroxide-decomposable olefin resin (d): (d) -1: "Grand Polypro J704" manufactured by Grand Polymer Co., Ltd. [block type polypropylene resin; MFR = 5 g / 10 minutes (230 ° C., 21 .2N),
Density = 0.90 g / cm ³ ] (d) -2: “Grand Polypro B701” manufactured by Grand Polymer Co., Ltd. [block type polypropylene resin; MFR = 0.5 g / 10 min (230 ° C., 21.2)
N), density = 0.90 g / cm ³ ]

(5) Organic peroxide (e): "Perhexa 25B-40" manufactured by NOF CORPORATION [2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 40 mass% content product , Supported material: Silica] (6) Crosslinking aid (f): "Tyke M" manufactured by Nippon Kasei
-60 "(triallyl isocyanurate, product containing 60% by mass, supported material: diatomaceous earth)

Examples 1 to 6 (1) The hydrogenated block copolymer (a), the non-aromatic softening agent for rubber (b), the peroxide-crosslinking olefin resin (c), and the peroxide. The decomposing olefin resin (d), the organic peroxide (e) and the crosslinking aid (f) were premixed in the amounts shown in Table 2 below, and then they were collectively packaged in a twin-screw extruder (Toshiba Machinery Co. Made "TEM-35
B)) and kneaded at a screw rotation speed of 200 rpm at the temperatures shown in Table 2 below, and then extruded in a strand shape and cut to produce pellets of the dynamically crosslinked thermoplastic elastomer composition. (2) Using the pellet obtained in (1) above, an injection molding machine (“IS-55EPN” manufactured by Toshiba Machine Co., Ltd., mold clamping pressure 55 ×)
10 ³ kg) and injection-molded under the conditions of a melting temperature of 230 ° C. and a mold temperature of 40 ° C., length × width × thickness = 110.
A sheet-shaped molded product having a size of mm × 110 mm × 2 mm was manufactured. About this molded product, hardness, tensile strength, tensile elongation,
The compression set, oil resistance and surface condition were measured or evaluated by the methods described above, and the results are shown in Table 2 below.

Comparative Examples 1 to 5 (1) The hydrogenated block copolymer (a), the non-aromatic rubber softening agent (b), the peroxide cross-linking olefin resin (c), and the peroxide. Decomposition type olefin resin (d), organic peroxide (e), crosslinking aid (f)
Was pre-mixed in the amount shown in Table 3 below, and then it was collectively supplied to a twin-screw extruder (“TEM-35B” manufactured by Toshiba Machine Co., Ltd.), and the screw rotation speed at the temperature shown in Table 3 below. 20
After kneading at 0 rpm, it was extruded in a strand shape and cut to produce pellets of the dynamically crosslinked thermoplastic elastomer composition. (2) Using the pellet obtained in (1) above, an injection molding machine (“IS-55EPN” manufactured by Toshiba Machine Co., Ltd., mold clamping pressure 55 ×)
10 ³ kg) and injection-molded under the conditions of a melting temperature of 230 ° C. and a mold temperature of 40 ° C., length × width × thickness = 110.
A sheet-shaped molded product having a size of mm × 110 mm × 2 mm was manufactured. About this molded product, hardness, tensile strength, tensile elongation,
The compression set, the oil resistance and the surface condition were measured or evaluated by the methods described above, and the results are shown in Table 3 below. In Comparative Example 2, the bleed-out of the non-aromatic softening agent for rubber (b) in the molded product was remarkable,
Further, in Comparative Example 5, the surface of the molded product was significantly roughened, and the quality of the molded product was poor in all cases. Therefore, the tests of hardness, tensile strength, tensile elongation, compression set and oil resistance were not conducted.

[0055]

[Table 2]

[0056]

[Table 3]

As is clear from the results shown in Table 2, in Examples 1 to 6, the hydrogenated block copolymer (a) having a number average molecular weight of 200,000 or more, the non-aromatic softening agent for rubber (b), A peroxide crosslinkable olefin resin (c) having a density of 0.94 g / cm ³ or more, a peroxide-decomposable olefin resin (d), an organic peroxide (e) and a crosslinking aid (f) are used, and water is used. Addition block copolymer (a) 10
50 parts by weight of the non-aromatic softening agent (b) for rubber
To 250 parts by mass, the peroxide-crosslinking olefin resin (c) is used in an amount of 2.5 to 50 parts by mass, and the peroxide-decomposing olefin resin (d) is further added. By setting the content within the range of 0.8 to 8 times the compounding amount of the peroxide-crosslinking olefin resin (c), it is possible to perform an extremely simple operation of melting and kneading all the components in one step under heating. Despite being adopted, the molded articles made of the thermoplastic elastomer compositions obtained in Examples 1 to 6 have excellent flexibility, rubber elasticity,
In particular, it has excellent rubber elasticity at high temperatures, a small compression set, and excellent mechanical strength and oil resistance.
Furthermore, it has no surface roughness or bleed-out and has excellent surface characteristics.

On the other hand, as is clear from the results of Table 3, in Comparative Example 1, the number average molecular weight of the hydrogenated block copolymer (a) was more than 200,000 in the production of the thermoplastic elastomer composition. By using the small hydrogenated block copolymer (a) -4, the molded article made of the thermoplastic elastomer composition obtained in Comparative Example 1 has an extremely large compression set at high temperature and Inferior in rubber elasticity. In Comparative Example 2, since the non-aromatic rubber softening agent (c) was used in an amount exceeding the amount specified in the present invention, molding of the thermoplastic elastomer composition obtained in Comparative Example 2 was performed. Bleedout of the softener in the product is remarkable. In Comparative Example 3, since the peroxide-crosslinking olefin resin (c) is not used, the molded article made of the thermoplastic elastomer composition obtained in Comparative Example 3 has a large compression set at high temperature. , Inferior in rubber elasticity at high temperature. In Comparative Example 4, the density of the peroxide-crosslinked olefin resin (c) was 0.94 g / cm.
By using (c) -2 of less than ³ , Comparative Example 4
The molded article made of the thermoplastic elastomer composition obtained in (1) above has a large compression set at high temperature, is inferior in rubber elasticity at high temperature, and has a large degree of swelling with oil and inferior oil resistance. In Comparative Example 5, the use of the peroxide-decomposable olefin-based resin (d) is less than that specified in the present invention, so that the surface roughness of the molded product is remarkable.

[0059]

According to the method of the present invention, a multi-step process is not required, and all the components are melted and kneaded together in a single step under heating. The composition can be easily produced with high productivity. In particular, the thermoplastic elastomer composition obtained by the method of the present invention and the molded article comprising the same are excellent in flexibility, rubber elasticity, particularly rubber elasticity at high temperature, and even when compressed for a long time at high temperature. It has a small compression set and excellent characteristics such as high-temperature creep performance, mechanical strength, oil resistance, solvent resistance, heat resistance, and weather resistance.In addition, surface roughness and bleed-out of softening agent to the surface Without a good appearance. The thermoplastic elastomer composition obtained by the method of the present invention can be effectively used for a wide range of applications including industrial parts due to the excellent physical properties described above.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F070 AA06 AA12 AA13 AA15 AA18                       AB08 AB22 AC44 AC45 AC56                       AC63 AC66 AC94 AE02 AE08                       GA05 GB08                 4J002 AE034 AE044 AE054 BB032                       BB052 BB123 BB143 BP011                       EA047 EH047 EK036 EK046                       EK056 EU137 FD024 FD146                       FD157

Claims (4)

[Claims] 1. A hydrogenated block copolymer containing (i) at least one polymer block A mainly containing a vinyl aromatic compound and at least one polymer block B mainly containing a conjugated diene compound. Hydrogenated block copolymer (a) having a number average molecular weight of 200,000 or more, a softening agent (b) for a non-aromatic rubber, and a peroxide-crosslinking olefin resin (having a density of 0.94 g / cm ³ or more ( c), a peroxide-decomposable olefin resin (d), an organic peroxide (e), and a crosslinking aid (f); and (ii) a non-aromatic rubber softening agent (b). Quantity
5 with respect to 100 parts by mass of the hydrogenated block copolymer (a)
0 to 250 parts by mass; (iii) 2.5 to 50 parts by mass of the peroxide-crosslinking olefin resin (c) based on 100 parts by mass of the hydrogenated block copolymer (a). And (iv) the amount of the peroxide-decomposing olefin resin (d) is 0.8 to 8 times the amount of the peroxide-crosslinking olefin resin (c). A method for producing a thermoplastic elastomer composition, which comprises melt-kneading and dynamically crosslinking under heating in a single step. 2. A polymer block B mainly composed of a conjugated diene compound in the hydrogenated block copolymer (a),
The method for producing a thermoplastic elastomer composition according to claim 1, which is a polymer block composed of 1,3-butadiene and isoprene. 3. The amount of the organic peroxide (e) added is 0.3 to 100 parts by weight of the total of (a) to (d).
1.5 parts by mass, and the addition amount of the crosslinking aid (f) is 0.5 to 3. with respect to the blending amount of the organic peroxide (e).
The method for producing the thermoplastic elastomer composition according to claim 1, wherein the amount is 0 times by mass. 4. A softening agent (b) for a non-aromatic rubber at 40 ° C.
The method for producing a thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the kinematic viscosity (Bv) (mm ² / s) in (4) satisfies the following formula. ## EQU1 ## Bv (mm ² / s) ≧ 3 × 10 ⁷ / Mna [In the above formula, Bv is 4 of the non-aromatic rubber softening agent (b)]
Kinematic viscosity at 0 ° C. and Mna represent the number average molecular weight of the hydrogenated block copolymer (a). ]