| 摘要 |
PROBLEM TO BE SOLVED: To provide a key pad soft to touch, scarcely increasing a pushing load, having abrasion resistance and useful for an input push-button switch of electronic machinery and apparatus or precision mechanical equipment, etc., by forming a urethane-based coating layer having a hardness within a specific range on the surface of the key pad made of a silicone rubber. SOLUTION: This key pad 1 is obtained by forming a urethane-based coating layer 3 having a hardness (y) defined by the formula (x)-10<=(y)<=(x)+20 on the surface of the key pad 1 made of a silicone rubber having a hardness (x). The hardness (x) is preferably 50-70. The urethane-based coating layer 3 is preferably obtained by further including 5-40 wt.% of a plasticizer having >=300 molecular weight [e.g. di(butoxyethoxyethyl) adipate] in a binary system coating material comprising, e.g. a polyol compound and an isocyanate compound and then curing the coating material. A letter or a symbol 2 may be printed on the surface of the key pad 1 by screen printing, etc. The film thickness of the coating layer is preferably 5-100μm.
|
