JP2000336239A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer which improves the scratch resistance and the wear resistance of a molded product without applying any coating and exerts an excellent heat resistance and molding processibility. SOLUTION: This composition is obtained by dynamically heating a mixture comprising (a) a block copolymer and/or a partially hydrogenated block copolymer comprising a polymer block A comprising styrene or its derivative and at least one polymer block B chosen from the group consisting of (B-1) an isoprene polymer block having a 1,4-bond content of 70% or smaller, (B-2) an isoprene/butadiene copolymer block having a 1,4-bond content of 70% or smaller and (B-3) a butadiene polymer block having a 1,4-bond content of 50% or smaller, (b) an olefin resin, (c) a silicone compound having two or more SiH groups within a molecule and (d) a hydrosilylation catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic elastomer composition. More specifically, the present invention relates to a thermoplastic elastomer composition having excellent scratch resistance, abrasion resistance, heat resistance, and moldability.

[0002]

2. Description of the Related Art Compounds comprising a styrene-based elastomer and PP are used for various purposes as thermoplastic elastomers and olefin resins having excellent impact resistance. However, this thermoplastic elastomer does not have sufficient scratch resistance due to a cloth, a nail, or the like, and requires post-treatment such as applying a coating to the molded article after molding the molded article requiring the scratch resistance. Was. In JP-A-9-48882, a higher fatty acid (such as oleamide, erucamide, or stearamide) is added to the thermoplastic elastomer in order to improve the scratch resistance of the thermoplastic elastomer. In this method, it is disclosed that scratch resistance is improved by bleeding a higher fatty acid on the surface of the thermoplastic elastomer.

However, when a cloth or the like comes into contact with the surface of the thermoplastic elastomer, higher fatty acids bleeding on the surface are scraped off, and the scratch resistance tends to be greatly reduced. JP-A-8-27325 discloses that a silicone oil having a viscosity of 30,000 centistokes or less is added to a thermoplastic elastomer to improve scratch resistance. However, in this method, the silicone oil tends to bleed on the surface of the thermoplastic elastomer with the passage of time and the appearance tends to be impaired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoplastic elastomer which has improved scratch resistance and abrasion resistance without applying a coating to a molded product, and which has excellent heat resistance and moldability. It is.

[0005]

That is, the first invention of the present invention comprises (a) a polymer block A of styrene or a derivative thereof, and an isoprene polymer having a 1,4 bond content of 70% or less or A block copolymer comprising a polymer block B which is an isoprene-butadiene copolymer and / or a partially hydrogenated block copolymer, (b) an olefin resin, and (c) two SiH groups in the molecule. A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising the above-mentioned silicone compound and (d) a hydrosilylation catalyst.

A second aspect of the present invention relates to (a) a polymer block A of styrene or a derivative thereof, wherein the content of 1,4 bonds is 7
0% or less of a block copolymer comprising a polymer block B which is an isoprene polymer or an isoprene-butadiene copolymer and / or a partially hydrogenated block copolymer, (b) an olefin resin, (c) ) Si in the molecule
A silicone compound having two or more H groups, (d) a hydrosilylation catalyst, (e) a polymer block A of styrene or a derivative thereof, and an isoprene polymer having a 1,4 bond content of 70% or more, or A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising a hydrogenated block copolymer comprising a polymer block C which is an isoprene / butadiene copolymer.

The third invention relates to (a) a polymer block A of styrene or a derivative thereof, wherein the content of 1,4 bonds is 7
0% or less of a block copolymer comprising a polymer block B which is an isoprene polymer or an isoprene-butadiene copolymer and / or a partially hydrogenated block copolymer, (b) an olefin resin, (c) ) Si in the molecule
A silicone compound having two or more H groups, (d) a hydrosilylation catalyst, (e) a polymer block A of styrene or a derivative thereof, and a butadiene polymer having a 1,4 bond content of 50% or more. A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising a hydrogenated block copolymer comprising a certain polymer block C.

A fourth aspect of the present invention relates to (a) a polymer block A of styrene or a derivative thereof, wherein the content of 1,4 bonds is 5
A block copolymer comprising a polymer block B which is a butadiene polymer of 0% or less and / or a partially hydrogenated block copolymer, (b) an olefin resin,
A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising (c) a silicone compound having two or more SiH groups in a molecule, and (d) a hydrosilylation catalyst.

In a fifth aspect of the present invention, a block copolymer comprising (a) a polymer block A of styrene or a derivative thereof and a polymer block B of a butadiene polymer having a 1,4 bond content of 50% or less is used. A polymer and / or a partially hydrogenated block copolymer, (b) an olefin resin, (c) a silicone compound having two or more SiH groups in a molecule, (d) a hydrosilylation catalyst, (e) ) Hydrogenation comprising a polymer block A of styrene or a derivative thereof and at least one polymer block C selected from the group of (C-1), (C-2) and (C-3) shown below. Block copolymer (C-1) Isoprene polymer block having a 1,4 bond content of 70% or more (C-2) Isoprene / butadiene copolymer having a 1,4 bond content of 70% or more Lock content of (C-3) 1,4 bond is a thermoplastic elastomer composition characterized by being obtained by dynamic heat treatment of the mixture consisting of butadiene polymer block is 50% or more.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (Block Copolymer) The block copolymer (a) used in the present invention comprises a polymer block A of styrene or a derivative thereof and a specific isoprene polymer or a specific isoprene / butadiene copolymer. It is composed of a block B made of a polymer or a specific butadiene polymer, and may be hydrogenated. The polymer component constituting the block A is styrene or a derivative thereof.
As the styrene derivative, α-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4
-Benzylstyrene, 4- (phenylbutyl) styrene and the like. Styrene is most preferred as the polymerization component constituting block A.

The polymer component constituting the block B is:
Isoprene polymer having a 1,4 bond content of 70% or less, isoprene / butadiene copolymer having a 1,4 bond content of 70% or less, or butadiene having a 1,4 bond content of 50% or less It is a polymer. The isoprene polymer having a 1,4 bond content of 70% or less, that is, the sum of the 1,2 bond content and the 3,4 bond content (hereinafter, referred to as "vinyl bond content") ) Is 30% or more. If the vinyl bond content of the isoprene polymer is only 30% or less, sufficient scratch resistance tends not to be obtained. The content of 1,4 bonds is 50
% Or less butadiene polymer means that the vinyl bond content (content of 1,2 bonds) is 50% or more. In the case of a butadiene homopolymer, good scratch resistance can be obtained when the vinyl bond content is 50% or more.
In the present invention, the polymer of the block B may be partially hydrogenated. The hydrogenation rate is preferably 98% or less. If it is 98% or more, crosslinking by a SiH group-containing silicone compound tends to be insufficient, and excellent abrasion resistance tends not to be obtained.

(Olefin resin) The olefin resin (b) used in the present invention includes polyethylene, polypropylene, ethylene-α-olefin copolymer, polybutene, polymethylpentene, etc., among which polyethylene, polypropylene, ethylene- α-olefin resins are preferred. Examples of the polypropylene include a propylene homopolymer, a random copolymer of propylene with 10 mol% or less of ethylene or other α-olefin, and a block copolymer of propylene with 30 mol% or less of ethylene or other α-olefin. And the like. As the polyethylene, ethylene homopolymer (HDPE, LD
PE) and a copolymer (LLDPE) of ethylene and another α-olefin of 10 mol% or less. As the ethylene-α-olefin copolymer, ethylene and 1
Copolymers with 0 mol% or more of α-olefin and the like can be mentioned. The above α-olefin is preferably one having 3 to 15 carbon atoms. As specific α-olefins, propylene, butene-1, octene-1, 4-methylpentene-1 and the like are preferable.

(Silicone Compound) In the present invention, the silicone compound (c) having two or more SiH groups in the molecule may have an unsaturated group, particularly a vinyl structure, of the block copolymer (a) during the heat treatment. It can selectively react with unsaturated groups having 1,2 bond or 3,4 bond to form a crosslinked structure. This hydrosilylation reaction does not decompose the resin component because it selectively cross-links the double bond,
No low molecular weight components are formed. In the case of peroxide crosslinking systems used for crosslinking common elastomers, they produce low molecular weight components such as polymer degradation and peroxide degradation products. For this reason, these low molecular weight components tend to bleed out to the surface of the material, and the feel and appearance tend to be impaired. However, the present invention can overcome the problems that occur when crosslinking is performed with the peroxide crosslinking system described above. In addition, since a silicone compound having two or more SiH groups in a molecule, which is a cross-linking agent, is incorporated into a cross-linked structure after heat treatment, appearance deterioration due to bleed-out hardly occurs.

Preferred examples of such a silicon compound include compounds having an organosiloxane structure such as cyclic organohydrogensiloxane, linear organohydrogensiloxane and tetrahedral organohydrogensiloxane, and compounds derived therefrom. can give. In order to increase the crosslinking density of the elastomer, it is preferable that the number of SiH groups in the silicon-based compound is large. Among these silicon compounds, linear polyorganohydrogensiloxanes having 5 or more SiH groups in the molecule are preferred, more preferably 10 or more, and most preferably 15 or more. Further, as a preferable silicone-based compound, a linear polyorganohydrogensiloxane composed of only a unit containing a SiH group as described below can be mentioned.

[0015]

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Wherein n is from 2 to 100, preferably 5
To 80. In producing the elastomer, the amount of the silicon compound is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the block copolymer (a). If the amount of the crosslinking agent is less than 0.1 part by weight, sufficient crosslinking may not be obtained and the wear resistance may not be sufficient. On the other hand, even if the compounding amount of the crosslinking agent is more than 30 parts by weight, the effect hardly increases and bleeding of the crosslinking agent may occur.

(Hydrosilylation catalyst) The hydrosilylation catalyst (d) is necessary for the crosslinking reaction with the silicone compound (c) having a SiH group to proceed at a practical rate. The hydrosilylation catalyst (d) used in the present invention is not particularly limited as long as it exhibits a catalytic action in the hydrosilylation reaction, but is preferably a compound or complex such as platinum, rhodium or palladium. Among them, a complex of platinum and an unsaturated group-containing siloxane compound is most preferably used in order to realize excellent wear resistance and scratch resistance. Specific examples of the unsaturated group-containing siloxane compound include divinyltetramethyldisiloxane and tetravinyltetramethylcyclotetrasiloxane.

In order to highly disperse these hydrosilylation catalysts in a material, a method in which a catalyst dissolved in a silicone oil or a solvent is kneaded in advance into a resin and used as a masterbatch, or supported on a solid component such as an inorganic filler is used. A method, a method of using by absorbing into a powdery resin or elastomer, and the like are preferable. As the resin to be kneaded, an olefin resin is preferable, and particularly, polyethylene, polypropylene and an ethylene-α-olefin copolymer are preferable. As the solid component to be supported, a carrier having an adsorption ability is used.For example, in the case of an inorganic system, an inorganic material such as calcium carbonate, carbon black, talc, mica, barium sulfate, natural silicic acid, synthetic silicic acid (white carbon), or titanium oxide is used. Fillers are mentioned, and among these, it is preferable to use synthetic silicic acid. Known methods may be used for preparing the catalyst supported on these carriers. Examples of the powdery resin or elastomer to be absorbed include polyethylene, polypropylene, various powder rubbers, and powdery styrene-based thermoplastic elastomers. Among them, styrene-based thermoplastic elastomers are preferable.

The amount of the platinum-based hydrosilylation catalyst to be added is preferably 0.0001 to 0.1 part by weight of platinum, more preferably 0.0005, based on 100 parts by weight of the block copolymer (a). To 0.01 parts by weight. If the addition amount is less than 0.0001 parts by weight, the reaction rate becomes slow and the time required for sufficient crosslinking becomes long. On the other hand, if the amount exceeds 0.1 part by weight, the effect is hardly increased, and the cost is likely to increase because the platinum-based catalyst is expensive.

(Hydrogenated block copolymer) In the present invention, a specific hydrogenated block copolymer (e) can be used if necessary. By using the block copolymer (a) and the hydrogenated block copolymer (e) in combination, it is possible to achieve both excellent compression set and excellent wear resistance and scratch resistance. The hydrogenated block copolymer (e) used in the present invention comprises a polymer block A of styrene or a derivative thereof and a block composed of a specific isoprene polymer or a specific isoprene-butadiene copolymer or a specific butadiene polymer. C, and is characterized by being hydrogenated.

The polymer component constituting the block A is as follows:
Styrene or a derivative thereof. As the styrene derivative, α-methylstyrene, 4-methylstyrene, 4-methylstyrene,
Propylstyrene, 4-cyclohexylstyrene, 4-
Dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene and the like.
Styrene is most preferred as the polymerization component constituting block A. The polymer component constituting the block C includes:
An isoprene polymer having a 1,4 bond content of 70% or more, an isoprene / butadiene copolymer having a 1,4 bond content of 70% or more, or a 1,4 bond content of 50% or more. It is a butadiene polymer. Block C
An excellent compression set is obtained when isoprene polymer and isoprene-butadiene copolymer having a 1,4 bond content of 70% or butadiene having a 1,4 bond content of 50% or more are used. Can be realized.

In the present invention, the polymer of the block C needs to be hydrogenated, and the hydrogenation rate is 90%.
It is preferably at least 95%, particularly preferably at least 95%. When the hydrogenation rate is 90% or more, excellent weather resistance and heat resistance can be realized. The ratio between the block copolymer (a) and the hydrogenated block copolymer (e) is 1 by weight.
It is preferably from 00/00 to 5/95, and more preferably from 90/10 to 5/95 in applications requiring compression set. When the proportion of the block copolymer (a) in the both block copolymers is 5% by weight or less, excellent abrasion resistance and scratch resistance tend to be insufficient. When the proportion of the hydrogenated block copolymer (e) in the both block copolymers exceeds 10% by weight, excellent compression set can be realized.

The proportion of the olefin resin (b) is preferably 10 to 150 parts by weight based on 100 parts by weight of the total of the block copolymer (a) and the hydrogenated block copolymer (e). When the proportion of the olefin resin is 10 parts by weight or less, the appearance of the molded article tends to be inferior, and when it is 150 parts by weight or more, the flexibility tends to be inferior.

(Other Additives) In the present invention, a paraffinic oil may be added as necessary for the purpose of adjusting the hardness of the obtained composition and giving flexibility. The paraffin oil used has a kinematic viscosity at 37.8 ° C of 20 to 500 cst and a pour point of -10 to-
Those having a temperature of 15 ° C and a flash point of 170 to 300 ° C are preferred. In the present invention, if necessary, an inorganic filler may be added. This inorganic filler not only has the advantage of reducing the product cost as a bulking agent, but also has the advantage of giving a positive effect on quality improvement (heat-resistant shape retention, flame retardancy, etc.). Examples of such inorganic fillers include calcium carbonate, carbon black, talc, magnesium hydroxide, mica, barium sulfate, natural silicic acid, synthetic silicic acid (white carbon), titanium oxide, and the like. Black, furnace black and the like can be used.

(Manufacturing method) The present invention (a), (b),
As a method of dynamically heat-treating by mixing the components (c) and (d), any of the known methods used in the production of ordinary thermoplastic elastomer compositions can be employed. Basically, it is a mechanical melt-kneading method, in which a single-screw extruder, a twin-screw extruder, a Banbury mixer, various kneaders, Brabender, rolls and the like are used. The order of addition of each component in the dynamic heat treatment is not particularly limited, and for example, an addition method such as melt-kneading components other than the catalyst in advance, further adding a hydrosilylation catalyst, and melt-kneading may be employed. Melt kneading temperature is 140 ° C ~ 300
C and the shear rate may be appropriately selected from the range of 100 to 5000 / sec. The thermoplastic elastomer composition of the present invention can be formed into a desired shape using a known thermoplastic resin molding machine. Such molding is injection molding,
It can be performed by various methods such as extrusion molding, calendar molding, blow molding and the like. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0026]

The present invention will be described in more detail with reference to the following examples. The components blended in the examples and comparative examples are as follows. <Block copolymer (a1)> Styrene-vinyl isoprene-styrene block copolymer HYBRAR5125 manufactured by Kuraray [styrene content 20 wt%, MFR (190 ° C 2.16 k
g [g / 10min]) 4, non-hydrogenated type | mold <block copolymer (a2)> Styrene-hydrogenated vinyl isoprene-styrene block copolymer HYBRAR7125 manufactured by Kuraray [styrene content 20wt%, MFR (190 ° C 2.16) k
g [g / 10min]) 0.7, partially hydrogenated type

<PP (b1)> Polypropylene resin (homo), Sumitomo Chemical W501 [MFR (230 ° C.) = 3.1 g / 10 min] <PP (b2)> Polypropylene resin (random), XF770 manufactured by Chisso
0 [MFR (230 ° C.) = 5 g / 10 min] <SiH silicone (c)> manufactured by Nippon Unicar Co., Ltd.

[0028]

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<Hydrosilylation catalyst (d)> Platinum vinylsiloxane complex (hydrosilylation catalyst) A platinum vinylsiloxane complex dissolved in polydimethylsiloxane and a 2.0 wt% solution of platinum were converted to high-density polyethylene (specific gravity 0). .95), and 4 g per 96 g was prepared and melt-kneaded. <Hydrogenated block copolymer (e)> Styrene-ethylene-propylene-styrene block copolymer Kuraray SEPTON4033 [styrene content 30 wt%, MFR (230 ° C 2.16k
g [g / 10min]) 0.05] <Other components: oil> Diana Process Oil PW-380 manufactured by Idemitsu Kosan Co., Ltd.
[Paraffinic process oil, kinematic viscosity: 381.6c
st (40 ° C), 30.1 (100 ° C), average molecular weight 7
46]

<Examples 1 to 6> Of the components described in Examples shown in Table 1, all components except component (d) were melt-kneaded at about 190 ° C. for 20 minutes using a kneader to form a roll sheet. did. The roll sheet was cooled to room temperature, pelletized with a sheet pelletizer, and a thermoplastic composition to be subjected to dynamic crosslinking was obtained. The components (d) shown in Table 1 are added to the pellets, and sufficiently plasticized according to the base resin at a shear rate of 800 / sec using a twin-screw kneader (resin temperature 180 ° C to 220 ° C). ) Kneading was performed to obtain a thermoplastic elastomer composition. Injection molding using this composition,
Various physical properties were evaluated. << Comparative Examples 1 to 4 >> Comparative Examples 1, 2, and 4 shown in Table 2 were performed in the same manner as Examples 1, 3, and 4, respectively, except for the component (c) and the component (d). Comparative Example 3 was performed in the same manner as in Example 4 except for the component a.

<Evaluation> The evaluation items of the obtained elastomers are shown below. (1) Hardness JIS K6301 A type (2) Tensile strength and elongation JIS K6301, No. 3 dumbbell (3) Heat resistant shape retention test 100 ° C compression set CS [%] (2
(5% compression, 100 ° C. × 22 hours) (4) Surface abrasion resistance test A 150 × 150 × 2 mm press sheet was prepared. HEIDON's HEIDON Gakudo Abrasion Tester HEID
Set the Kanakin No. 3 cloth on the abrasion jig in ON-14DR, put the abrasion jig on the press sheet surface, measure once with a vertical load of 100 g, a moving speed of 100 mm / min, and a moving distance of 50 mm. Observation was made by visual observation, and x was given when the trace of wear was completely observed, Δ was given when the trace was slightly observed, and ○ was given when no trace was observed.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

According to the present invention, it is possible to provide a thermoplastic elastomer which has improved scratch resistance and abrasion resistance without applying a coating to a molded product, and has excellent heat resistance and molding workability. Therefore, it can be applied to various uses in which these characteristics are required.

Claims (6)

[Claims] (A) a polymer block A of styrene or a derivative thereof and a polymer block B of an isoprene polymer or an isoprene / butadiene copolymer having a 1,4 bond content of 70% or less. A block copolymer and / or a partially hydrogenated block copolymer,
A thermoplastic elastomer obtained by dynamically heat-treating a mixture comprising (b) an olefin resin, (c) a silicone compound having two or more SiH groups in a molecule, and (d) a hydrosilylation catalyst. Composition. (A) a polymer block A of styrene or a derivative thereof and a polymer block B of an isoprene polymer or an isoprene-butadiene copolymer having a 1,4 bond content of 70% or less. A block copolymer and / or a partially hydrogenated block copolymer,
(B) an olefin resin, (c) a silicone compound having two or more SiH groups in a molecule, (d) a hydrosilylation catalyst, (e) a polymer block A of styrene or a derivative thereof, and containing 1,4 bonds. A thermoplastic polymer obtained by dynamically heat-treating a mixture comprising a hydrogenated block copolymer comprising a polymer block C which is an isoprene polymer or an isoprene-butadiene copolymer having an amount of 70% or more. Elastomer composition. (A) a polymer block A of styrene or a derivative thereof and a polymer block B of an isoprene polymer or an isoprene / butadiene copolymer having a 1,4 bond content of 70% or less. A block copolymer and / or a partially hydrogenated block copolymer,
(B) an olefin resin, (c) a silicone compound having two or more SiH groups in a molecule, (d) a hydrosilylation catalyst, (e) a polymer block A of styrene or a derivative thereof, and containing 1,4 bonds. A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising a hydrogenated block copolymer comprising a polymer block C which is a butadiene polymer having an amount of 50% or more. 4. A block copolymer comprising (a) a polymer block A of styrene or a derivative thereof and a polymer block B which is a butadiene polymer having a 1,4 bond content of 50% or less and / or A partially hydrogenated block copolymer, (b) an olefin resin, (c) a silicone compound having two or more SiH groups in a molecule, (d)
A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising a hydrosilylation catalyst. 5. A block copolymer comprising (a) a polymer block A of styrene or a derivative thereof and a polymer block B of a butadiene polymer having a 1,4 bond content of 50% or less and / or A partially hydrogenated block copolymer, (b) an olefin resin, (c) a silicone compound having two or more SiH groups in a molecule, (d)
Hydrosilylation catalyst (e) Polymer block A of styrene or a derivative thereof and (C-1), (C)
-2), a hydrogenated block copolymer (C-1) composed of at least one polymer block C selected from the group of (C-3), isoprene polymer having a 1,4 bond content of 70% or more. From the isoprene-butadiene copolymer block (C-3) in which the content of the combined block (C-2) 1,4 bond is 70% or more, butadiene polymer block in which the content of the 1,4 bond is 50% or more A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture comprising: 6. The thermoplastic elastomer composition according to claim 1, wherein the olefin resin is at least one selected from the group consisting of polypropylene, polyethylene, and ethylene-α-olefin copolymer.