JPH05171004A - Elastomer composition with improved scratch resistance - Google Patents

Abstract

(57) [Summary] [Structure] (a) A block copolymer composed of a polymer block A mainly containing at least two vinyl aromatic compounds and a polymer block B mainly containing at least one conjugated diene compound. Hydrogenated block copolymer obtained by hydrogenating a: a: 50 to 80% by weight (b) Polypropylene or a copolymer containing it as a main component b: 5 to 20% by weight (c) for a non-aromatic rubber Softening agent c: 0 to 45% by weight (d) An elastomer composition in which the thermoplastic polyurethane elastomer resin d is 5 to 20 parts by weight based on 100 parts by weight of the above a + b + c. [Effect] It has excellent scratch resistance, flexibility, weather resistance, and workability, so it is used for automobiles, home appliances, toy parts, sundries, etc., but especially suitable for interior and exterior parts of automobiles that require product appearance. Is.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an elastomer composition which is excellent in scratch resistance (durability of scratches on the surface), has high gloss, is flexible, has weather resistance, and can be used as a raw material for various molded products. It is about.

[0002]

2. Description of the Related Art Conventionally, a thermoplastic elastomer composition having a molding processability similar to that of a thermoplastic resin is used for automobile parts, home electric appliances parts, electric wire coatings, and miscellaneous goods, where vulcanized rubber has been the mainstream. Examples of these include olefin elastomers composed of ethylene-propylene copolymer and polypropylene, polyurethane elastomers, soft polyvinyl chloride, chlorinated polyethylene and the like.

However, at present, these molding materials have drawbacks in terms of scratchability, flexibility, processability, economic efficiency, and recycling performance. That is, although the olefin elastomer is relatively inexpensive and has excellent weather resistance and heat resistance, it is inferior in flexibility and scratch resistance. Polyurethane elastomer has excellent wear resistance, but flexibility,
It has the disadvantages of poor workability and high cost.
Soft polyvinyl chloride is relatively inexpensive and has excellent weather resistance and scratch resistance, and is used for automobile exterior parts, but its hardness changes greatly with temperature and its flexibility at low temperatures is problematic. Further, in recent years, the use of polyvinyl chloride resins, which cause hydrogen chloride generation during incineration due to the problem of waste plastic treatment, has been restricted.

Further, some proposals have been made for an elastomer composition using a hydrogenated derivative of a vinyl aromatic compound-conjugated diene compound block copolymer (hereinafter abbreviated as hydrogenated block copolymer). .. For example, JP-A-50-14742, JP-A-52-65551, and JP-A-58-206644 disclose compositions in which a hydrogenated block copolymer is mixed with a rubber softening agent and an olefin polymer. Is disclosed in Japanese Patent Laid-Open No. 3-234.
Japanese Patent No. 755 discloses a composition in which a hydrogenated block copolymer is blended with an acid-modified hydrogenated block copolymer and a thermoplastic polyurethane elastomer.

However, these compositions were also inferior in scratch resistance as were the olefin elastomers.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and has flexibility, weather resistance,
An object of the present invention is to provide an elastomer composition having improved scratch resistance while taking advantage of the characteristics of a hydrogenated block copolymer having excellent processability.

[0007]

The present invention comprises (a) a polymer block A containing at least two vinyl aromatic compounds as a main component and a polymer block B containing at least one conjugated diene compound as a main component. Hydrogenated block copolymer a obtained by hydrogenating a block copolymer:
50-80% by weight (b) Polypropylene or a copolymer containing it as a main component b: 5-20% by weight (c) Softener for non-aromatic rubber c: 0-45% by weight (d) Thermoplastic polyurethane An elastomer composition having improved scratch resistance, wherein the elastomer resin d is 5 to 20 parts by weight based on 100 parts by weight of a + b + c.

The present invention will be described in detail below. The hydrogenated block copolymer used as the component (a) in the present invention is a polymer block A mainly containing at least two vinyl aromatic compounds and a polymer block B mainly containing at least one conjugated diene compound. Is obtained by hydrogenating a block copolymer consisting of 5 to 50% by weight of a vinyl aromatic compound,
It preferably contains 15 to 40% by weight.

Further referring to the block structure, the polymer block A mainly containing a vinyl aromatic compound contains a vinyl aromatic compound polymer block or a vinyl aromatic compound in an amount of more than 70% by weight, preferably 90% by weight or more. The polymer block B has a structure of a copolymer block of a vinyl aromatic compound and a hydrogenated conjugated diene compound, and further, a polymer block B mainly composed of the hydrogenated conjugated diene compound is hydrogenated. Structure of conjugated diene compound polymer block or copolymer block of hydrogenated conjugated diene compound and vinyl aromatic compound containing more than 50% by weight, preferably 70% by weight or more of hydrogenated conjugated diene compound Is to have.

The distribution of the hydrogenated conjugated dieu compound or vinyl aromatic compound in the polymer block A and the polymer block B is random, tapered (in which the monomer component increases or decreases along the molecular chain),
It may be in the form of a partial block or any combination thereof, and each of the polymer block mainly containing the vinyl aromatic compound and the polymer block mainly containing the hydrogenated conjugated diene compound are two. In the above cases, the polymer blocks may have the same structure or different structures.

The vinyl aromatic compound constituting the hydrogenated block copolymer includes styrene, α-methylstyrene,
One or more kinds are selected from vinyltoluene and the like, and styrene is particularly preferable. As the conjugated diene compound, one kind or two or more kinds are selected from butadiene, isoprene, 1,3-pentadiene and the like, and among them, butadiene, isoprene and a combination thereof are particularly preferable.

The number average molecular weight of the above block copolymer is 20,000 to 300,000, preferably 30,000.
The range is 0 to 200,000, and the molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) is preferably 1.05 to 5. The molecular structure of the block copolymer may be linear, branched, radial, or a combination thereof. Furthermore, when butadiene is used as the conjugated diene compound in the block copolymer,
The amount of 1,2 bonds in the microstructure of the butadiene portion is 20 to 20.
It is in the range of 50%, preferably 35 to 45%.

The block copolymer may be produced by any known production method as long as it has the above-mentioned structure. For example, a vinyl aromatic compound-conjugated diene compound is synthesized in an inert solvent using a lithium catalyst or the like by the method described in JP-B-40-23798, and then, for example, JP-A-60-220147, JP-A-61-131313
It can be synthesized by hydrogenation in the presence of a hydrogenation catalyst in an inert solvent by the method described in JP-A No. 2 or JP-A-62-207303.

At this time, at least 80% of the aliphatic double bonds of the conjugated diene compound can be hydrogenated so that the polymer block containing the conjugated diene compound as a main component can be morphologically converted into an olefinic compound polymer block. . The hydrogenation rate of the aromatic double bond based on the vinyl aromatic compound is not particularly limited, but 20% or less is preferable. The amount of the end-hydrogenated aliphatic double bond contained in the hydrogenated block copolymer can be easily known by a nuclear magnetic resonance apparatus.

The polypropylene used as the component (b) of the present invention or the copolymer containing it as a main component has, for example, an MFR (230 ° C., 2.16 kg load) of 0.5 to 4.
It is generally used for molding at 0 g / 10 min, and is an essential component for improving the heat distortion resistance and processability of the obtained composition. For example, polypropylene, polypropylene and ethylene, α-such as 1-butene. Examples thereof include random copolymers with olefins and block copolymers.

The non-aromatic softening agent for rubber used as the component (c) of the present invention has the effect of improving the flexibility and processability of the resulting composition and is generally known as a mineral oil softening agent. Known paraffinic and naphthenic rubber oils can be used, paraffinic oils are preferred, and paraffinic oils containing 5% or less of the aromatic ring component are desirable.

The thermoplastic polyurethane resin used as the component (d) of the present invention is an essential component for improving scratch resistance. The thermoplastic polyurethane resin is not particularly limited, and polyester-based, polycarbonate-based, and polyether-based resins that are easily available as thermoplastic polyurethane elastomers for general molding can be used in the composition of the present invention.

The above (a), (b), (c), (d)
The composition of the present invention comprising the essential components of (a) contains 50 to 80% by weight of the hydrogenated block copolymer as the component (a). If the hydrogenated block copolymer is less than 50% by weight, the scratch resistance is inferior. If it exceeds 5% by weight, the flowability is abnormal and the processability, especially extrusion moldability, is poor, which is not preferable. The hydrogenated block copolymers may be used alone or in combination of two or more. Next, the polypropylene as the component (b) is contained in the composition in an amount of 5 to 20% by weight. If the amount of the propylene is less than 5% by weight, the flow characteristics at the time of melting are abnormal and the workability, especially the extrusion formability is poor. If it exceeds, scratch resistance is significantly reduced, which is not preferable.

It is particularly preferably 5 to 15% by weight.
The paraffinic oil as the component (c) is contained in an amount of 0 to 45% by weight, and if it exceeds 45% by weight, scratch resistance and mechanical strength are poor, which is not preferable. The thermoplastic polyurethane elastomer of the component (d) of the present invention is (a) + (b) + (c) 10.
The content of 5 to 20 parts by weight relative to 0 parts by weight is less than 5 parts by weight, and the effect of improving scratch resistance is small. The compatibility is poor, and the resulting molded article is inferior in appearance, which is not preferable.

In addition to the above-mentioned essential components, the composition of the present invention may optionally contain an anti-blocking agent, a lubricant, a pigment, a silicone oil, a light stabilizer, an ultraviolet absorber, an oxidative deterioration inhibitor, a flame retardant and the like. be able to. As a method for kneading the composition of the present invention, a method used for producing a usual resin composition or a rubber composition can be adopted, and it is easy to use a melt kneader such as an extruder, a heating roll, a Banbury mixer, and various kneaders. It is possible to knead, and as a molding processing method, processing methods such as extrusion molding, injection molding, blow molding and compression molding can be applied.

[0021]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical properties used in Examples and Comparative Examples were measured by the following test methods. (1) Hardness A indication specified in JIS-K-6301 (JIS A hardness) (2) Pencil hardness Loaded using a pencil specified in JIS S6006 using a pencil scratch tester for coating film (JIS K5401) A scratch test was carried out at 50 g, and the hardness was examined from the traces of flaws on the surface of the test piece to evaluate scratch resistance (difficulty in scratching the surface). As for the hardness code, 9H is the hardest and 4B is the softest, and the higher the hardness code, the better the scratch resistance. For the determination, the hardness of the black specular test piece surface was visually determined by scratching while changing the hardness of the pencil. (Eg 3
If it is not scratched by H and is scratched by 4H, pencil hardness is 3H, 4
When scratched with B, the pencil hardness was <4B. (3) Workability The surface of the extruded strand was visually observed and evaluated according to the following scale.

◯: The strand surface is smooth and glossy. X: The surface of the strand is rough and has no gloss. In addition, each compounded ingredient is as follows. (1) <(a) component>: Hydrogenated block copolymer (SE
B) It has a structure of SEB-1 B-A-B-A and has a bonded styrene content of 20% by weight, a number average molecular weight of 74,000, a molecular weight distribution of 1.08, and a 1,2-vinyl bond of the polybutadiene portion before hydrogenation. 36
%, A hydrogenated block copolymer having a hydrogenation rate of 99% is disclosed in
SE synthesized by the method described in JP-A-33132
It was designated as B-1 component. The impact resilience of SEB-1 was measured and found to be 63%.

It has a structure of SEB-2 ABA and has a bound styrene content of 30%, a number average molecular weight of 36000, a molecular weight distribution of 1.09, and 50% of 1,2-vinyl bonds in the polybutadiene portion before hydrogenation. A hydrogenated block copolymer having a hydrogenation rate of 99% is disclosed in JP-A-63-1313.
SEB-2 component was synthesized by the method described in Japanese Patent Publication No.

SEB-3 B-A-B-A structure, 40% by weight of bound styrene, number average molecular weight of 53,000, molecular weight distribution of 1.07, 1,2-vinyl bond of polybutadiene before hydrogenation Is 36
%, A hydrogenated block copolymer having a hydrogenation rate of 99% is disclosed in
SEB-synthesized by the method described in No. 33132
Three components were used. (2) <(b) component> Asahi Kasei polypropylene resin MFR (230 ° C, 2.16 kg load) P P-1 M1600 14g / 10min P P-2 M1700 30g / 10min (3) <(c) component> Idemitsu Kosan Co., Ltd. Dyna Process Oil PW-380 [paraffin type, kinematic viscosity; 381.6 cst / 40 ° C.,
30.1 cst / 100 ° C., average molecular weight; 746, ring analysis; Cn = 27%, Cp = 73%] (4) <(d) component> Polyurethane resin Pantex T-5000V manufactured by Dainippon Ink and Chemicals, Inc. [Type: Ester-Based, Hardness (JIS A) 82] (5) Modified Hydrogenated Block Copolymer The modified hydrogenated block copolymers used in Comparative Examples 6 and 7 are styrene / butadiene blocks having a linear SEBS bush. The hydrogenated product of the copolymer is modified with maleic anhydride, and has a styrene content of 35% by weight, a maleic anhydride addition amount of 1.0% by weight, and an MFR (200 ° C., 5 kg load) of 2.0 g / 10 min. have. (6) Colorant Carbon masterbatch (40% carbon-containing polyethylene resin)

[0025]

Examples 1 to 11 and Comparative Examples 1 to 7 The components shown in Tables 1, 2 and 3 were mixed in the indicated amounts and melt-kneaded with a 30 mm diameter twin-screw extruder to obtain resin composition pellets. It was The pellets are sandwiched between ferro plates and the heating plate temperature is 180 to 190.
A 2 mm specular sheet was prepared with a compression molding machine at ℃, and the pencil hardness of the sheet was measured. The specular surface sheet was colored black so that scratches could be easily determined by a pencil hardness test. The processability was evaluated by visually observing the surface of the strand from the extruder during melt kneading of the resin composition.

In Examples 1 to 7 and Comparative Examples 1 to 3, Table 1 shows the blending amounts of the hydrogenated block copolymer, polypropylene and paraffin oil PW-380 and the measurement results. As is clear from Examples 1 to 7 and Comparative Examples 1 to 3,
It can be seen that the composition of the present invention is a desirable composition having excellent scratch resistance and processability.

In Examples 8 to 10 and Comparative Examples 4 to 5,
Table 2 shows the measurement results of the composition in which the blending amount of the thermoplastic polyurethane resin was changed with respect to the predetermined blending amount of the hydrogenated block copolymer, polypropylene and paraffin oil PW-380.
Described in. As is clear from Examples 8 to 10 and Comparative Examples 4 to 5, it can be seen that the composition of the present invention using an appropriate amount of the thermoplastic polyurethane resin is a desirable composition excellent in scratch resistance and processability.

In Example 9 and Comparative Example 6, hydrogenated block copolymer, polypropylene, paraffin oil PW
-380, the measurement results of the composition in which the modified hydrogenated block copolymer is blended with the thermoplastic polyurethane resin are shown in Table 2. As is clear from Example 9 and Comparative Example 6, it is understood that the composition of the present invention is a desirable composition having excellent scratch resistance and processability.

In Examples 11 and 12 and Comparative Example 7, paraffin oil P was added to the hydrogenated block copolymer, polypropylene, and thermoplastic polyurethane resin in the prescribed amounts.
Table 3 shows the measurement results of the compositions in which the compounding amount of W-380 was changed. As is clear from Examples 11 and 12 and Comparative Example 7, it is understood that the composition of the present invention is a desirable composition having excellent scratch resistance and processability.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

The resin composition obtained by the present invention is excellent in scratch resistance, flexibility, weather resistance and workability,
It can be used in the fields of automobile parts, home electric appliance parts, toy parts, sundries, etc., but weather strips, malls, etc. that require a product appearance due to its particularly excellent scratch resistance.
It can be suitably used for interior and exterior parts of automobiles such as instrument panels and armrests.

Claims (1)

[Claims] 1. A hydrogenated block copolymer comprising (a) a polymer block A mainly containing at least two vinyl aromatic compounds and a polymer block B mainly containing at least one conjugated diene compound. Hydrogenated block copolymer a: 50-80% by weight (b) Polypropylene or a copolymer containing it as a main component b: 5-20% by weight (c) Non-aromatic softening agent for rubber c: 0 to 45% by weight (d) An elastomer composition in which the thermoplastic polyurethane elastomer resin d is 5 to 20 parts by weight based on 100 parts by weight of a + b + c.