Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-09-21
2002-05-28
Nutter, Nathan M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S193000, C525S194000, C525S203000, C525S205000, C525S221000, C525S232000, C525S233000, C525S236000, C525S241000, C525S244000
Reexamination Certificate
active
06395833
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a thermoplastic elastomeric resin composition and resin granules thereof having an excellent fluidity suited to powder molding.
DESCRIPTION OF THE PRIOR ART
Powder molding methods, such as rotational powder molding, are widely used to produce a surface akin for automobile interior parts, such as instrumental panels, console boxes and the like. To easily provide the molded skin with leather grain patterns or stitches on their surfaces so as to attain softness to touch, polyvinyl chlorides have been used. However, from the environmental viewpoint, thermoplastic elastomers or polyurethane resins are increasingly used instead of the polyvinyl chlorides.
A rotational powder molding method is mainly used to mold the thermoplastic elastomers or the polyurethane resins. For this molding method, the powder should have good fluidity in order that the powder adheres uniformly on the surface of a mold with a complicated shape, and also that an excess charge of the powder is removed easily.
For the purpose of providing thermoplastic elastomeric resin powder having an improved fluidity, various kinds of thermoplastic elastomer and powder thereof have been proposed. For example, Japanese Patent Application Laid-Open H10-45976 discloses thermoplastic elastomer powder having a sphere-equivalent average diameter of larger than 0.7 mm to 1.20 mm and a bulk density of at least 0.38, where the thermoplastic elastomer is prepared by dynamically vulcanizing a composition comprising a polyolefin resin and ethylene-&agr;-olefin copolymer rubber. Japanese Patent Application Laid-Open H10-81793 discloses powder comprising the aforesaid resin composition and a hydrogenated conjugated diene polymer or a random copolymer of a hydrogenated conjugated diene polymer with a vinyl aromatic compound. Japanese Patent Application Laid-Open H10-182900 discloses a thermoplastic elastomer for powder slush molding comprising a polypropylene resin, hydrogenated styrene butadiene rubber, a process oil and an elastomer such as styrene/ethylene-propylene/styrene block copolymer. Likewise, Japanese Patent Application Laid-Open H11-60826 discloses a powdery resin composition comprising a polyolefin type polymer and a hydrogenated diene type polymer, wherein stickiness of the resins is suppressed so as to improve the fluidity.
These powder resins are prepared by several methods. For example, one method is a freeze-crushing method where the resin is frozen with liquid nitrogen or the like and crushed in a mill such as a turbo mill, a roller mill, and a hammer mill. Another method is to extrude a resin through a die into a strand which is then drawn, cooled, and subsequently cut. Likewise, the powder resins may be prepared by crushing the thermoplastic elastomer at a temperature of its glass transition or below, and then treating with a solvent.
These powder resins, however, tend still to adhere and coagulate, and still need improvement in its fluidity. In addition, the powder resins are difficult to handle on site and also cause problems due to dust. Accordingly, it is an object of the invention to solve the above-mentioned fluidity problem associated with powder resins in powder molding.
Further, because the sheer force applied to a molten resin is smaller in powder molding, the resin should therefore have a good melt flowability in its molten state to give a uniform thickness to the molded article. Usually, in the powder molding of a thermoplastic elastomer, a sufficient melt flowability cannot be attained unless a mold temperature is set considerably high, e.g., 300° C., compared to that for polyvinyl chloride. The mold is repeatedly heated to such a high temperature and cooled. As a result, the mold deteriorates faster due to metal fatigue. Accordingly, it is another object of the invention to provide a thermoplastic elastomeric resin composition having a good melt flowability even at lower mold temperatures.
In addition, molded articles obtained from thermoplastic elastomers are not satisfactory in terms of oil resistance and abrasion resistance. Japanese Patent Application Laid-Open H10-310617 discloses a thermoplastic elastomer composition comprising a polyurethane resin, in which the composition has improved oil resistance and abrasion resistance. The composition is intended to be subjected to injection molding, and therefore does not have a melt flowability sufficient for powder molding. Accordingly, it is still another object of the invention to provide thermoplastic elastomeric resin composition having excellent oil resistance and abrasion resistance as well as good melt flowability.
SUMMARY OF THE INVENTION
A purpose of the present invention is to provide a resin composition having good melt flowability. Thus, the present invention is a thermoplastic elastomeric resin composition for powder molding, comprising
a composition prepared by dynamically vulcanizing
100 parts by weight of (a) a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
20 to 300 parts by weight of (b) a non-aromatic softening agent for rubber,
10 to 150 parts by weight of (c) a peroxide-decomposing olefinic resin and/or a copolymer containing said resin,
0.01 to 15 parts by weight of (d) an unsaturated glycidyl compound,
0.01 to 15 parts by weight of (e) an unsaturated carboxylic acid or a derivative thereof, and
1 to 30 parts by weight of (f) a liquid polybutadiene, and
10 to 2,500 parts by weight of (h) at least one material selected from the group consisting of polyester polymers and copolymers; polyurethane polymers and copolymers, and polyamide polymers and copolymers;
characterized in that
10 to 200 parts by weight of (p) a compound represented by the following chemical formula (I) is also dynamically vulcanized or kneaded with said vulcanized composition or with said vulcanized composition and component (h):
H
2
C═CH—CH
2
—O—(C
n
H
2n
O)
m
—X (I)
wherein n is an integer of from 2 to 5, C
n
H
2n
may be branched, x represents B or CH═CH
2
, m is the number of the repeating unit C
n
H
2n
O, and a number average molecular weight of the compound is in a range of from 200 to 6,000.
In the aforesaid composition, it is preferred that component (p) is a chemical compound represented by the following chemical formula (II) or (III):
H
2
C═CH—CH
2
—O—(C
3
H
6
O)
m1
—H (II)
wherein the number average molecular weight is in a range of from 1,200 to 1,800,
H
2
C═CH—CH
2
—O—(C
3
H
6
O)
m2
—CH═CH
2
(III)
wherein the number average molecular weight is in a range of from 2,500 to 3,500.
The present invention also provide a thermoplastic elastomeric resin composition for powder molding, comprising
a composition prepared by dynamically vulcanizing
100 parts by weight of (a) a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
20 to 300 parts by weight of (b) a non-aromatic softening agent for rubber,
10 to 150 parts by weight of (c) a peroxide-decomposing olefinic resin and/or a copolymer containing said resin,
0.01 to 15 parts by weight of (d) an unsaturated glycidyl compound,
0.01 to 15 parts by weight of (e) an unsaturated carboxylic acid or a derivative thereof, and
1 to 30 parts by weight of (f)a liquid polybutadiene; and
10 to 2,500 parts by weight of (u) a thermoplastic polyurethane resin, characterized in that said component (u) is derived from a polyol having a number average molecular weight of from 600 to 3,000 and has a number average molecular weight of from 10,000 to 500,000.
Further, the present invention provide a thermoplastic elastomeric resin composition having good flowabilit
Tasaka Michihisa
Yamanaka Toshimi
Nutter Nathan M.
Pitney Hardin Kipp & Szuch LLP
Riken Technos Corporation
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