JP3303005B2 - Thermoplastic elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be used as a material for various molded products which are rich in flexibility, have excellent compression set resistance at high temperatures, oil resistance, mechanical strength and good weather resistance. The present invention relates to a thermoplastic elastomer composition.

More specifically, a specific hydrogenated block copolymer,
A novel dynamically vulcanized thermoplastic elastomer composition obtained by blending a softener for a non-aromatic rubber, a polyolefin resin, a reactive alkylphenol / formaldehyde resin, and optionally a hydrotalcite compound, and kneading the mixture by heating and kneading. It is.

[0003]

2. Description of the Related Art In recent years, thermoplastic elastomers which do not require a vulcanization step and have the same moldability as thermoplastic resins have been widely used in the fields of automobile parts, home appliance parts, sundries, footwear and the like. It has become.

Above all, vinyl aromatic compound-conjugated diene compound block copolymers such as styrene-butadiene block copolymer and styrene-isoprene block copolymer have elasticity and feel similar to those of conventional vulcanized rubber. Therefore, the vulcanized rubber has been evaluated as being suitable as a molded article material in which the vulcanized rubber has been used.

However, the above vinyl aromatic compound-conjugated diene compound block copolymer is inferior in heat resistance, weather resistance and oil resistance as a thermoplastic elastomer to vulcanized rubber, so that its use range is limited. was there.

A thermoplastic elastomer comprising a hydrogenated product of a vinyl aromatic compound-conjugated diene compound block copolymer (hereinafter referred to as a hydrogenated block copolymer) having improved these disadvantages has been improved in weather resistance and heat resistance. However, oil resistance was the same as before, and heat resistance was still insufficient.

Several proposals have been made for elastomer compositions using this hydrogenated block copolymer. For example, JP-A-52-65551 and JP-A-5-55551
JP-A-8-206644 discloses an elastomer composition obtained by blending an olefin polymer, a hydrocarbon oil and an inorganic filler with a hydrogenated block copolymer, and further discloses JP-A-59-6236, and JP-A-59-131
No. 613 discloses an elastomer composition obtained by partially crosslinking an elastomer composition obtained by blending an olefin polymer, a hydrocarbon oil and an inorganic filler with a hydrogenated block copolymer in the presence of an organic peroxide and a crosslinking monomer. Proposals have been made to improve the compression set resistance of articles at high temperatures. Also, JP-A-63-99256 and JP-A-63-112649 disclose the mechanical strength and the high temperature of a hydrogenated block copolymer composition obtained by partially crosslinking in the presence of an organic peroxide. In order to improve the compression set resistance, a hydrogenated block copolymer is blended with a polyolefin resin and a softening agent for rubber and optionally an olefin copolymer to form a reactive alkylphenol /
A hydrogenated block copolymer composition dynamically vulcanized with a formaldehyde resin is disclosed.

[0008]

However, of these prior art proposals, the hydrogenated block copolymer composition obtained by dynamic vulcanization using a reactive alkylphenol / formaldehyde resin is resistant to compression set at high temperatures. Although the properties are improved, it cannot be said that the metal halides or organic halides are used as a vulcanization accelerator during dynamic vulcanization with a reactive alkylphenol / formaldehyde resin. Hydrogen hydride is contained in the hydrogenated block copolymer composition, and weather resistance (Sunshine Weatherometer: 83
(Retention rate of tensile strength at 500 ° C. × 500 hours), and the oil resistance was also insufficient.

The present invention has been made to solve the problems which have been difficult with the above-mentioned conventional elastomer molding materials. In particular, the present invention has a processability as a thermoplastic elastomer and a possibility of recycling scrap. It has been made based on the demand for molding materials that have excellent compression set and mechanical strength at high temperatures, good weather resistance and oil resistance at high temperatures, and can satisfy performances that have never been achieved before. It has been found that this demand can be sufficiently achieved by dynamically vulcanizing a hydrogenated block copolymer having a specific hydrogenation rate with a specific composition, and furthermore, a practically useful composition. It is what has been done.

[0010]

That is, the present invention provides (a) a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one conjugated diene compound. hydrogenating a block copolymer consisting of a hydrogen addition rate of the aliphatic double bonds based on the conjugated diene compound is greater than 60%, less than 85% unmodified hydrogenated block copolymer 100 Parts by weight (b) Softener for non-aromatic rubber 20 to 200 parts by weight (c) Polyolefin resin 15 to 150 parts by weight (d) Reactive alkylphenol / formaldehyde resin 0.3 to 30 parts by weight (e) Hydrotalcite A dynamically vulcanized thermoplastic elastomer composition comprising 0 to 50 parts by weight of a similar compound.

Hereinafter, the present invention will be described in detail.

The hydrogenated block copolymer used as the component (a) in the present invention comprises at least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound. It is a hydrogenated block copolymer obtained by hydrogenating a block copolymer consisting of united blocks B. That is, for example,

[0013]

Embedded image This is produced by hydrogenating a vinyl aromatic compound-conjugated diene compound block copolymer having such a structure.

The hydrogenated block copolymer contains 5 to 60% by weight, preferably 10 to 55% by weight of a vinyl aromatic compound. Further, when referring to the block structure, it is mainly composed of the vinyl aromatic compound. The polymer block A is a vinyl aromatic compound polymer block or a copolymer of a vinyl aromatic compound containing more than 50% by weight, preferably 70% by weight or more of a vinyl aromatic compound and a hydrogenated conjugated diene compound. The polymer block B, which has a block structure and is mainly composed of a hydrogenated conjugated diene compound, comprises a hydrogenated conjugated diene compound polymer block or a hydrogenated conjugated diene compound. More than 70% by weight
It has a structure of a copolymer block of a hydrogenated conjugated diene compound and a vinyl aromatic compound contained above.

The polymer block A mainly composed of a vinyl aromatic compound and the polymer block B mainly composed of a hydrogenated conjugated diene compound have a hydrogenated molecular chain in each polymer block. Distribution of the conjugated diene compound or vinyl aromatic compound is random,
It may be tapered (the monomer component increases or decreases along the molecular chain), may be partially block-shaped, or may be composed of any combination thereof. When there are two or more polymer blocks each containing a conjugated diene compound as a main component, each of the polymer blocks may have the same structure or different structures.

The vinyl aromatic compounds constituting the hydrogenated block copolymer include, for example, styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, p-tert.
One or more of butylstyrene, 1,1'-diphenylethylene and the like can be selected, and among them, styrene is preferable. Further, as the conjugated diene compound before hydrogenation constituting the hydrogenated conjugated diene compound, for example,
Butadiene, isoprene, 1,3-pentadiene, 2,
One or more kinds are selected from 3-dimethyl-1,3-butadiene and the like, and among them, butadiene, isoprene and a combination thereof are preferable. The polymer block mainly composed of the conjugated diene compound before hydrogenation can have any microstructure in the block. For example, in a polybutadiene block, the amount of 1,2-vinyl bond is 10 to 10. 65%, preferably 20-55%.

The number average molecular weight of the hydrogenated block copolymer having the above structure and used in the present invention is 5,000.
~ 1,000,000, preferably 10,000-50
3,000 to 300,000 to 300,00 to maintain the balance between the physical properties and processability of the composition of the present invention.
0 is a more preferable range, and the molecular weight distribution [ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / M
n)] is 10 or less. Further, the molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or any combination thereof.

The method for producing these block copolymers may be any method as long as it has the above-mentioned structure. For example, according to the method described in Japanese Patent Publication No. 40-23798,
A vinyl aromatic compound-conjugated diene compound block copolymer is synthesized in an inert solvent using a lithium catalyst or the like, and then, for example, JP-B-42-8704 and JP-B-43
Although it can be obtained by the method described in US Pat. No. 6,636,698, it was synthesized using a titanium-based hydrogenation catalyst exhibiting excellent performance in weather resistance and heat deterioration resistance of the obtained hydrogenated block copolymer. Hydrogenated block copolymers are most preferred. For example, JP-A-59-133203 and JP-A-60-133
According to the method described in JP 79005, hydrogenation can be carried out in an inert solvent in the presence of a titanium-based hydrogenation catalyst to synthesize the hydrogenated block copolymer used in the present invention.

At this time, the hydrogenation rate of the aliphatic double bond based on the conjugated diene compound of the vinyl aromatic compound-conjugated diene compound block copolymer is more than 60% and less than 85%. Preferably it is more than 65% and less than 75%. When the hydrogenation rate is 60% or less, the resulting dynamic vulcanization composition has good compression set and oil resistance at high temperatures (100 ° C.) at high temperatures (100 ° C.), but has poor mechanical strength and elongation. The amount of the aliphatic double bond based on the conjugated diene compound of the hydrogenated block copolymer increases, the compatibility with the non-aromatic rubber softener deteriorates, and the surface of the injection-molded product of the composition has an oil. Bleeding occurs, which is not preferable. When the hydrogenation rate is 85% or more, the amount of the aliphatic double bond based on the conjugated diene compound, which becomes a crosslinking point at the time of the crosslinking reaction with the reactive alkylphenol / formaldehyde resin, decreases, and the mechanical strength and elongation are good. However, the compression set and oil resistance at high temperatures are deteriorated, and the compression set is particularly remarkably deteriorated.

An aromatic double compound based on a vinyl aromatic compound copolymerized with a polymer block A mainly composed of a vinyl aromatic compound and, if necessary, a polymer block B mainly composed of a conjugated diene compound. The hydrogenation rate of the bond is not particularly limited, but the hydrogenation rate is preferably 20% or less. The amount of unhydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be easily known by an infrared spectrophotometer, a nuclear magnetic resonance apparatus, or the like.

The softener for non-aromatic rubber used as the component (b) in the present invention is an essential component for making the resulting composition a flexible rubber-like composition. Mineral oils or liquid or low molecular weight synthetic softeners are suitable. A mineral oil-based rubber softener generally called a process oil or extender oil used for softening, increasing the volume of a rubber, and improving processability is a mixture of an aromatic ring, a naphthene ring, and a paraffin chain. Those in which the number of carbon atoms in the paraffin chain accounts for 50% or more of the total carbon are called paraffinic, and those having 30 to 45% naphthenic ring carbon are naphthenic or those having more than 30% aromatic carbon. Is considered to be aromatic. The mineral oil-based rubber softener used as the component (b) of the present invention is preferably a naphthene-based or paraffin-based one in the above category, and an aromatic-based one having an aromatic carbon number of 30% or more is
It is not preferable to mix the component (a) with the component (a) because the Tg (glass transition point) of the hard segment of the component (a) is lowered. Therefore, as the component (b) used in the present invention, a softener for non-aromatic rubber, which is a paraffin oil substantially containing no aromatic carbon, can be more preferably provided. The properties of these softeners for non-aromatic rubbers are described in 37.
The kinematic viscosity at 8 ° C. is 20 to 500 cst, and the pour point is −
Those having a temperature of 10 to -15 ° C and a flash point of 170 to 300 ° C can be used. In addition, liquid polybutene, liquid low molecular weight polybutadiene, and the like can be used as the synthetic softener, but the above-mentioned softener for mineral oil-based rubber gives better results.

The compounding amount of the softener of the component (b) is 20 to 200 parts by weight, preferably 30 to 150 parts by weight, per 100 parts by weight of the component (a). If the amount exceeds 200 parts by weight, the softener tends to bleed out and the final product may be tacky. In addition to the decrease in mechanical strength, it is not preferable in terms of heat creep performance. . If the amount is less than 20 parts by weight, the resulting composition is close to the resin composition, the hardness is increased, the flexibility is lost, and economical aspects are not preferred.

Next, the polyolefin resin used as the component (c) of the present invention is effective not only for improving workability during molding but also for improving oil resistance and heat resistance. Examples of the polyolefin resin used here include polyethylene, ultra-high-molecular-weight high-density polyethylene, isotactic polypropylene, and copolymers of propylene and other small amounts of α-olefins, such as propylene / ethylene copolymer and propylene / 1. -Hexene copolymer, propylene / 4-methyl-1-pentene copolymer, and poly (4
-Methyl-1-pentene), polybutene-1 and the like. In particular, when a polypropylene resin is used, the MFR (ASTM-D1238-L condition, 230
C) is 0.1 to 50 g / 10 min, especially 0.5 to 30 g / min.
Those having a range of 10 minutes can be suitably used.

The amount of the component (c) is based on 100 parts by weight of the hydrogenated block copolymer of the component (a).
It can be suitably selected in the range of 15 to 150 parts by weight, and particularly preferably 20 to 100 parts by weight. If the amount exceeds 150 parts by weight, the resulting composition has excellent oil resistance, but the hardness is too high to obtain a rubber-like composition, and the composition loses its flexibility at high temperatures (100 ° C.). Rubber elasticity (compression set) is extremely deteriorated, which is not preferable. If the amount is less than 15 parts by weight, the resulting composition has excellent rubber elasticity at high temperatures as a rubber-like property, but has poor oil resistance and workability, which is not preferable.

Next, the reactive alkylphenol / formaldehyde resin used as the component (d) of the present invention is:
General formula:

[0026]

Embedded image (Where n is an integer of 0 to 5, X is a hydroxyl group or a halogen group, Y is hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, Z
Is a halogen group or a hydrocarbon group having 1 to 20 carbon atoms, R ′
Is _{-CH 2 -, - CH 2 OCH} 2 - represents a bond)
And a known reactive alkylphenol / formaldehyde resin which is generally known as a resol type phenol resin and can be used as a resin vulcanizing agent for rubber.

This resin is generally obtained by a binding reaction between a substituted phenol and an aldehyde in an alkaline medium, or a phenol cured resin obtained by a binding reaction of a bifunctional phenol dialcohol. As long as the resin has the above-mentioned structure, any method may be used for producing the phenol-cured resin, and the disclosure of a method for producing such a phenol-cured resin and a vulcanization system using the same are disclosed in, for example, US Pat. 370
Nos. 9840, 297,2600 and 3093
613.

Specific examples of this resin include commercially available Tackirol 201 and Tackirol 25.
0-1 (manufactured by Taoka Chemical Co., Ltd.)
SP-1045, Schenectady SP-10
55 (Schenectady Chemicals
Co. Manufactured).

This resol type phenol resin can be used alone, but a vulcanization accelerator can be used in combination to adjust the vulcanization rate. Examples of the vulcanization accelerator include metal halides (stannic chloride, ferric chloride), organic halides (chlorinated polyethylene, chlorosulfonated polyethylene, chlorinated paraffin, brominated butyl rubber, chloroprene ), zinc oxide, Magnesium oxide
Can be used. Among them, methylolphenol /
When a formaldehyde resin is used as a vulcanizing agent, a metal halide is used, and when a brominated phenol / formaldehyde resin is used, zinc oxide is preferable because it shows a good vulcanization accelerating effect. The hydrogenated block copolymer composition having a specific hydrogenation rate, which is dynamically vulcanized using the component (d) and a vulcanization accelerator optionally used together, can be prepared by using a known reaction type alkylphenol / formaldehyde resin. Compared to the dynamically vulcanized hydrogenated block copolymer composition, it shows extremely good compression set and oil resistance under high temperature, good mechanical strength, no oil bleed on the molded product surface, and excellent It shows the unexpected unexpected performance balance.

Here, the hydrogenated block copolymer composition dynamically vulcanized means that 1 g of the composition obtained in the present invention is refluxed for 10 hours with a Soxhlet extractor using boiling xylene, and the residue is 80 mesh. The gel content (%) represented by a value obtained by multiplying the ratio of the dry weight (g) of the insoluble matter remaining on the mesh / the weight (g) of the component (a) contained in 1 g of the composition by 100 times by filtration through a wire mesh of Is at least 50%, preferably 80% or more, more preferably 90% or more (however, insoluble components such as hydrotalcites and other inorganic fillers are not included in the vulcanized product), In addition, the vulcanization is performed during melt-kneading of the hydrogenated block copolymer composition. In order to obtain such a dynamically vulcanized hydrogenated block copolymer composition, the amount of the component (d) is 0.3 to 100 parts by weight of the hydrogenated block copolymer.
It can be suitably selected from 30 parts by weight, preferably 5 to 25 parts by weight, and the compounding amount of the vulcanization accelerator used in some cases is 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight. And the gel content thereof can be adjusted. When the amount of (d) exceeds 30 parts by weight,
The coloring of the composition based on the reactive alkylphenol / formaldehyde resin is undesirably large. 0.3
If the amount is less than part by weight, the crosslinking reaction of the hydrogenated block copolymer is not sufficiently performed, the gel content is reduced, and the compression set and oil resistance at high temperatures are deteriorated.

In the present invention, a hydrotalcite compound as the component (e) may be optionally added.
The hydrotalcite compounds used as the component (e) include hydrotalcite (chemical structure [Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H), which is a natural mineral produced in the Ural region of the USSR and Snarim of Norway. ₂ O]) and a synthetic product having the similar structure, the general ^{_{formula: M 1-X 2+ M X}} 3+ (OH) 2 + X-nY a Y n- · mH 2 O ( wherein M ^{2 +} Is Mg ²⁺ , Zn ²⁺ , Ca ²⁺ , Ni ²⁺ , Co
²⁺ represents two metal ions selected from the group consisting of Mn ²⁺ and Cu ²⁺ , and M ³⁺ represents a trivalent metal ion selected from the group consisting of Al ³⁺ , Fe ³⁺ and Cr ³⁺ . Represents a metal ion, and A ^n- is H
CO ₃ ^-, CO ₃ ^2- and OH ^- n selected from the group consisting of
X, Y, and m are each a positive number and satisfy the following conditions: 0.1 <X <0.5, 0.1 <Y <0.40 ≦ m <
1) which can be produced according to known methods, for example, the methods disclosed in JP-B-46-2280, JP-B-50-30039, JP-B-52-335 and the like. Commercially available hydrotalcite compounds include those having the chemical structure [Mg _4.5 Al ₂ (OH) ₁₃
CO ₃ .3.5H ₂ O] trade name DHT-4A, chemical structure [Mg _4.2 Al ₂ (OH) _12.4 CO ₃ ] trade name DHT-
4A-2, chemical structure [Mg ₆ Al ₂ (OH) ₁₆ CO _3.
4H ₂ O] tradename queue word 500 (all manufactured by Kyowa Chemical Co.) and the like, are those usually used in the resin of the thermal stability improving agent.

The amount of component (e) is 50 parts or less, preferably 1 to 30 parts, per 100 parts by weight of component (a). In less than 1 part, due to hydrotalcites,
The effect of capturing the halogen contained in the composition is not sufficient, and although the composition can be practically used, the weather resistance is reduced. 3
If the amount exceeds 0 parts, the weather resistance is sufficient, but the mechanical strength and elongation are poor, which is not preferable.

In the present invention, an inorganic filler can be further added as required.

Examples of the inorganic filler used here include calcium carbonate, carbon black, talc, clay, magnesium hydroxide, mica, barium sulfate, natural silicic acid, synthetic silicic acid (white carbon), titanium oxide, and magnesium oxide. , Zinc oxide and the like, and as the carbon black, channel black, furnace black, royal black and the like can be used. Of these inorganic fillers, talc, calcium carbonate and furnace black are economically advantageous and preferred. It is also possible to add a conductive filler to impart conductivity. For example, conductive carbon such as Ketjen black may be used.

The method for producing the dynamically vulcanized hydrogenated block copolymer composition of the present invention can be a method used in the production of ordinary resin compositions or rubber compositions.
Compounding can be performed using a melt-kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a heating roll, a Brabender, or various kneaders.

At this time, the components (a) to (d) and, if necessary, the vulcanization accelerator are previously mixed at room temperature with a Henschel mixer or the like, and then dynamically vulcanized while heating and kneading at a temperature of 150 to 300 ° C. After that, if necessary, a method of melt-kneading the component (e) or the inorganic filler at a temperature of 150 to 250 ° C. or a part of the component (b) and the components (a), (c), (d) and, depending on the case, The vulcanization accelerator is previously mixed with a Henschel mixer or the like, and then dynamically vulcanized while being heated, melt-kneaded at a temperature of 150 to 300 ° C., and then the remainder of (b) and, if necessary, the component (e) and inorganic filler Or melt-kneading at a temperature of 150 to 250 ° C. or the components of (a) to (d) are mixed in advance with a Henschel mixer or the like, and then heated and melt-kneaded at a temperature of 150 to 300 ° C., and in some cases vulcanization is accelerated. After melt kneading and dynamic vulcanization, Depending on the requirements (e) method of the component and inorganic filler are melt-kneaded at a temperature of 150 to 250 ° C. can also be employed.

Accordingly, the method for producing the hydrogenated block copolymer composition is not limited as long as it has the characteristics of the above-mentioned dynamically vulcanized hydrogenated block copolymer composition.

The thus obtained dynamically vulcanized hydrogenated block copolymer composition of the present invention can be obtained by compounding the above-mentioned components. If necessary, a flame retardant, a glass fiber , Carbon fiber, nylon fiber, antioxidant, heat stabilizer, ultraviolet absorber, hindered amine light stabilizer, colorant, petrolatum, paraffin, polyethylene wax, linseed oil, epoxidized soybean oil, soybean oil,
Ester plasticizers such as dioctyl phthalate and dioctyl adipate can also be added.

Further, the dynamically vulcanized hydrogenated block copolymer composition of the present invention has thermoplasticity in spite of containing a vulcanized product, so that a commonly used thermoplastic resin molding machine can be used. And various molding methods such as injection molding, extrusion molding, blow molding, and calendar molding are applicable.

[0040]

The present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto.
The hydrogenation rate of the component (a) and the test methods used for various evaluations in Examples and Comparative Examples are as follows.

(1) Method of Measuring Hydrogenation Rate The raw polymer before hydrogenation and the hydrogenated polymer were converted into a carbon disulfide solution and subjected to FT-IR (Perkin Elmer 160).
(Type 0) and the amount of bound styrene was determined according to the Hampton method, and S ₀ and S ₁ (%), and the hydrogenation rate was calculated by the following equation.

[0042]

(Equation 1)

(2) Hardness [-] JIS-K6301, A type

(3) Tensile strength [kg / cm ² ] JIS-K6301, a 2 mm thick compression molded sheet was used as a sample, and a test piece was a No. 3 dumbbell.

(4) Compression set [%] JIS-K6301, 100 ° C. × 22 hours, 25% deformation

(5) Oil resistance No. specified in JIS-K6301. 3 Using test oil (lubricating oil) at 70 ° C for 2 hours, 50mm x 50mm x 2mm
A thick test piece was immersed, and the weight change (%) before and after immersion was determined.

(6) Weather resistance Using a sunshine weatherometer manufactured by IBIDEN Co., Ltd.
Retention rate (%) of tensile strength (kg / cm ² ) at 83 ° C. × 500 hours

(7) Oil bleed Using Toshiba Machine Co., Ltd. IS55EPN injection molding machine, injection temperature: 220 ° C., injection speed: 60%, 50 mm ×
A color plate of 90 mm × 2.5 t was prepared, and the presence or absence of oil bleed was confirmed by a tentacle.

The components that were blended are as follows.

(1) Component (a) <Component (a-1)> has a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene, a bound styrene content of 33%, a number average molecular weight of 166,000, A hydrogenated block copolymer having a molecular weight distribution of 1.10, a 1,2-vinyl bond content of a polybutadiene portion before hydrogenation of 37%, and a hydrogenation rate of 70% was obtained by the method described in JP-A-60-790.
Synthesis was carried out using a Ti-based hydrogenation catalyst described in Japanese Patent Publication No. 05-2005 as Component (a-1).

<Component (a-2)> It has a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene, and has an amount of bound styrene of 35.
%, Number average molecular weight 183000, molecular weight distribution 1.12,
Before the hydrogenation, the amount of 1,2-vinyl bond in the polybutadiene portion is 3
A hydrogenated block copolymer having a hydrogenation rate of 5% and a hydrogenation rate of 82% was synthesized using the catalyst described above to obtain a component (a-2).

<Component (a-3)> having the structure of polystyrene-hydrogenated polybutadiene-polystyrene,
Bound styrene content 30%, number average molecular weight 155,000, molecular weight distribution 1.08, 1,2 of polybutadiene part before hydrogenation
-A hydrogenated block copolymer having a vinyl bond content of 38% and a hydrogenation rate of 65% was synthesized using the above-mentioned catalyst to obtain Component (a-3).

<Component (a-4)> (Polystyrene-hydrogenated polybutadiene) having a structure of _4- Si, a bound styrene content of 18%, a number average molecular weight of 143,000, a molecular weight distribution of 1.38, and polybutadiene before hydrogenation A hydrogenated block copolymer having a 1,2-vinyl bond content of 32% and a hydrogenation rate of 52% was synthesized using the catalyst described above to obtain the component (a-
4).

<Component (a-5)> It has a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene, and has a bound styrene content of 29.
%, Number average molecular weight 168,000, molecular weight distribution 1.08,
Before the hydrogenation, the amount of 1,2-vinyl bond in the polybutadiene portion is 3
A hydrogenated block copolymer having a hydrogenation ratio of 6% and a hydrogenation rate of 89% was synthesized using the catalyst described above to obtain Component (a-5).

<Component (a-6)> It has a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene, and has an amount of bound styrene of 35.
%, Number average molecular weight 179000, molecular weight distribution 1.06,
The 1,2-vinyl bond content of the polybutadiene part before hydrogenation is 38.
%, And a hydrogenated block copolymer having a hydrogenation rate of 97% was synthesized using the catalyst described above to obtain Component (a-6).

<Component (a-7)> having the structure of polystyrene-hydrogenated polybutadiene-polystyrene,
KRATON-G-1651 having a bound styrene content of 33%
(Shell Chemical Co., Ltd.) was used as the component (a-7).

(2) Component (b) Diana Process Oil PW-380 manufactured by Idemitsu Kosan Co., Ltd.
[Paraffin-based process oil, kinematic viscosity: 381.6c
st (40 ° C.), average molecular weight 746, ring analysis; C _A =
0%, C _N = 27%, C _P = 73%]

(3) Component (c) Polypropylene resin manufactured by Asahi Kasei Corporation, E-1100 [M
FR (230 ° C.) = 0.5 g / 10 min]

(4) Component (d) <Component (d-1)> Thermal reaction type alkylphenol / formaldehyde resin manufactured by Taoka Chemical Co., Ltd., Tackirol
-201 <Component (d-2)> Reactive brominated alkylphenol / formaldehyde resin manufactured by Taoka Chemical Co., Ltd., Tackir
ol 250-1

(5) Component (e) Hydrotalcite compounds manufactured by Kyowa Chemical Co., Ltd., DHT
-4A-2

(6) Component (f) Clay manufactured by ENGEL HARD, UW-90

(7) Component (g) Vulcanization accelerator <Component (g-1)> Stannous chloride (S) manufactured by Rare Production Metals Co., Ltd.
nCl ₂ .2H ₂ O) <Component (g-2)> Reagent primary zinc oxide manufactured by Wako Pure Chemical Industries, Ltd.

Example 1 All the components shown in Table 1 were mixed with a Henschel mixer, melt-kneaded in a 30 mm diameter twin screw extruder at 190 to 220 ° C., and dynamically vulcanized. A combined composition was obtained. The polymer was subjected to compression molding to measure various physical properties, and the results are shown in Table 2.

Examples 2 to 4 and Comparative Examples 1 to 4 Compositions were obtained in the same manner as in Example 1 using the components shown in Table 1. The evaluation results are shown in Table 2. As is clear from Table 2,
In Comparative Example 1 with a hydrogenation rate of 52%, although compression set and oil resistance were good, oil bleeding occurred, and tensile strength was slightly inferior. Comparative Examples 2 and 4 with a hydrogenation rate of 89% The compression set and oil resistance were inferior, and Comparative Example 3 having a hydrogenation rate of 97% was significantly inferior in compression set and oil resistance.

REFERENCE EXAMPLE 1 Using the components shown in Table 1, kinematic vulcanization was performed using 1.2 parts by weight of an organic peroxide [2,5-dimethyl-2,5-di (tert-butylperoxy) hexane] and divinylbenzene. (DVB) A composition was obtained in the same manner as in Example 1, except that 4 parts by weight was used. Table 2 shows the evaluation results. Although weather resistance was excellent as compared with Examples 1-4, other physical properties were quite inferior.

Examples 5 to 8, 10, 11 All components except (e) and (f) shown in Table 3 were mixed with a Henschel mixer, and dynamic vulcanization was carried out in the same manner as in the above examples. . Thereafter, the pelletized, dynamically vulcanized hydrogenated block copolymer composition and the components (e) and (f) are mixed again with a Henschel mixer, and the mixture is subjected to a temperature of 180 to 200 ° C. by a twin-screw extruder having a diameter of 30 mm. Was melt-kneaded. Various properties were measured using this polymer, and the results are shown in Table 4. Examples 1 to 5 which were not added by the addition of component (e)
As compared with No. 4, the weather resistance was improved, and the other physical properties were the same and showed an excellent balance of physical properties.

Example 9 A composition was obtained in the same manner as in Example 1 using the components shown in Table 3. The evaluation results are shown in Table 4.

Comparative Examples 5 and 6 Using the components shown in Table 3, compositions were obtained in the same manner as in Example 1. The evaluation results are shown in Table 4. As is clear from Table 4, Comparative Example 5 in which the component (d) was less than 0.3 parts by weight was inferior in compression set resistance and oil resistance, and the component (c) was 15%.
Comparative Example 6, which was less than part by weight, was not a thermoplastic elastomer and could not be molded.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

[Table 3]

[0072]

[Table 4]

[0073]

As described above, a hydrogenated block having a specific hydrogenation rate in a hydrogenated block copolymer composition obtained by blending a known reaction type alkylphenol / formaldehyde resin and dynamically vulcanizing. By using the copolymer, it exhibits compression set and oil resistance at 100 ° C. which is much higher than expected, and the addition of a specific halogen scavenger optionally improves weather resistance, improves mechanical strength and The appearance of the molded article was also found to be good.

That is, when a hydrogenated block copolymer having a hydrogenation rate of 60% or less is used, not only the compression set at 100 ° C. is excellent but the mechanical strength is insufficient, but also the molded article surface Oil bleeding occurred and was not practical. When the hydrogenation ratio is 85% or more, the mechanical strength is excellent, but the compression set resistance at 100 ° C. and the oil resistance are insufficient.

Claims (1)

(57) [Claims] 1. A block copolymer comprising (a) at least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound. 100 parts by weight of a hydrogenated unmodified hydrogenated block copolymer having a hydrogenation rate of an aliphatic double bond based on the conjugated diene compound of more than 60% and less than 85% From 20 to 200 parts by weight of a softening agent for rubbers (c) from 15 to 150 parts by weight of a polyolefin resin (d) from 0.3 to 30 parts by weight of a reactive alkylphenol / formaldehyde resin (e) from 0 to 50 parts by weight of a hydrotalcite compound A dynamically vulcanized thermoplastic elastomer composition comprising: