| 摘要 |
PURPOSE: To obtain a key pad capable of thermoforming and having a good feeling of clicking by using a composition comprising a specified copolymer of ethylene with an anotherα-olefin and an ethylene/propylene/diene terpolymer. CONSTITUTION: A resin composition comprising 20-90 pts.wt. polyethylene resin (A) being a copolymer of ethylene with anα-olefin other than ethylene and having a density of 0.86-0.88g/cm<3> and 80-10 pts.wt. ethylene/propylene/diene terpolymer (B) is melt-kneaded and formed into a key pad by e.g. injection molding. Component A is made by polymerization in the presence of a catalyst being a metallocene compound containing a tetravalent transition metal. It is desirable that theα-olefin used in component A is of 6-8C from the viewpoints of the mechanical strengths and flexibility of a key pad. Component B desirably contains ethylidene-norbornene and has a propylene content of 20-60wt.%. It is desirable that Component B is dispersed in component A in the form of particle of 50μm or below desirably 20μm or below, and the resulting dispersion is optionally subjected to vulcanization by addition of a vulcanizing agent.
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