Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1998-08-19
2000-03-07
Wu, David W.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524515, 524587, C08K 334
Patent
active
060341653
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to propylene-based resin compositions and automobile trim members, and more precisely, to propylene-based resin compositions having good impact resistance, good scratch-whitening resistance and good weld appearance with little uneven gloss and to automobile trim members made by injection-molding of the composition.
BACKGROUND ART
Non-coated automobile trim members are being popularized for the purpose of reducing the production costs, for which there is increasing a great demand for materials having good characteristics of outward appearance and a quiet feel while preventing light reflection. In addition, the requirements of safe and economical materials are being on a higher level, and inexpensive materials with good impact resistance are desired.
As the materials of automobile trim members, much used are inexpensive, popular propylene-based resins. It is known that addition of styrene-based elastomers to propylene-based resins is effective for improving the impact resistance (room temperature Izod impact strength) of the resins. However, styrene-based elastomers are expensive and are problematic in that the moldings comprising them shall have an increased degree of surface gloss. Moreover, adding a large amount of rubber components to propylene-based resins for the purpose of improving the impact resistance of the resins is further problematic in that the scratch-whitening resistance of the resin moldings is poor.
On the other hand, known are molding materials having good low-temperature impact resistance. For example, disclosed are resin compositions comprising a crystalline propylene-ethylene block copolymer and an ethylene-.alpha.-olefin copolymer as produced in the presence of a metallocene catalyst (see Japanese Patent Application Laid-Open (JP-A) Hei-7-145272, JP-A Hei-7-145298); resin compositions comprising a propylene-based resin and an ethylene-butene-1 copolymer having a relatively large butene-1 unit content (the copolymer is produced substantially in the presence of a metallocene catalyst) (see JP-A Hei-6-192506, JP-A Hei-7-18151); and resin compositions comprising a propylene-based resin and an ethylene-octene-1 copolymer having a relatively large octene-1 content (the copolymer is produced substantially in the presence of a metallocene catalyst) (see International Patent Application Laid-Open No. 94-6859).
Though having good low-temperature impact resistance, those resin compositions are still defective in that their moldings often have uneven gloss and poor scratch-whitening resistance.
DISCLOSURE OF THE INVENTION
Given that situation, we, the inventors have made the present invention, and the object of the invention is to provide propylene-based resin compositions having good impact and scratch-whitening resistance and good weld appearance with little uneven gloss and to provide automobile trim members to be made by injection-molding of the composition. The members do not require coating, and are therefore economical.
The inventors have assiduously studied and, as a result, have found that a resin composition that comprises a propylene-based resin having specific properties to which are added a specific impact-resistant agent, a high-density polyethylene and talc can attain the object noted above. On the basis of this finding, the present invention has been completed.
Specifically, the present invention provides, as the first invention (I), a propylene-based resin composition comprising (A) from 42 to 95% by weight of a propylene-based resin having an isotactic pentad fraction of at least 95%, (B) from 1 to 10% by weight of an ethylene-C.sub.3 -18 .alpha.-olefin copolymer having a density of from 0.850 to 0.875 g/cm.sup.3 and a melt index of from 0.01 to 25 g/10 min, and prepared in the presence of a metallocene catalyst, (C) from 2 to 18% by weight of a high-density polyethylene having a density of from 0.93 to 0.97 g/cm.sup.3 and a melt index of from 0.5 to 10 g/10 min, and (D) from 2 to 35% by weight of talc, the total of the compon
REFERENCES:
patent: 5219913 (1993-06-01), Tomomatsu et al.
Domininghaus, Plastic for Engineers-Materials, Properties, Applications, Hanser, p. 105, 1993.
Ishii Toshiyuki
Nara Toshihide
Ohnishi Satoru
Tomomatsu Ryuzou
Choi Ling-Siu
Idemitsu Petrochemical Co. Ltd.
Wu David W.
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