| 摘要 |
<p>PROBLEM TO BE SOLVED: To make a golf club shaft light in weight by decreasing the quantity of resin as a whole and to practically keep the rigidity of the shaft even when lightening is attained by making the weight ratio of resin less than 33% concerning fiber reinforced thermosetting resin. SOLUTION: A 1st layer 2 of a golf club shaft 1 uses a prepreg obtained by immersing thermosetting resin in fibers arranged in prescribed direction and a 2nd layer 3 uses a prepreg to which the quantity of immersion is less than that in the case of the 1st layer. Then, the ratio occupied by the resin of the thicker prepreg in the 1st layer 2, namely, the resin content (RC) is from 33W% to 37W% similarly to the conventional shaft and the RC of the 2nd layer 3 is less than 22W%. When this shaft is put into a burning furnace and burnt for two or three hours almost at 140 deg.C, the temperature inside the burning furnace is increased on the initial stage of burning, the resin on the fibers inside the two layers of prepregs is made into gell and flows, this is absorbed by the 2nd layer 3, the immersion of resin is almost averaged and the average RC is made less than 33W%.</p> |
