| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve a hit feeling and controllability by winding stringy thermoplastic elastomer around a core to form a middle layer and by covering the core with a cover. SOLUTION: While both a liquid core or a solid core are acceptable core, the solid core is more preferable. A thermoplastic elastomer component is wound like a string around the core to form a middle layer of which thickness is 1.0 to 5.0 mm. For example, an interrelated group of polystyrene is used for the thermoplastic elastomer, and titanous oxide, tungsten, fillers such as an age resister, and an additive agent are mixed. A hardness of the thermoplastic elastomer component is over 45 degrees of JIS-C hardness, preferably less than about 100 degrees, furthermore the hardness of 45 to about 65 degrees is more preferable. This makes it possible to improve a hit feeling and controllability.</p> |
