| 摘要 |
PROBLEM TO BE SOLVED: To obtain an NBR composition simultaneously satisfying various properties required for valve materials or packing materials for beer barrels and useful as a valve material for beer barrels meeting the food sanitation law by compounding a blend polymer with silica, calcium carbonate and/or the like, and an organic peroxide. SOLUTION: This NBR composition is obtained by compounding (A) a blend polymer composed of (i) 50-90 wt.% of NBR and (ii) 50-10 wt.% of polyvinyl chloride or chlorinated polyethylene with (B) silica (pref. synthetic silica <=30μm in particle size), (C) at least one of calcium carbonate, calcium oxide and calcium hydroxide, and (D) pref. 1-5 pts.wt., based on 100 pts.wt. of the component A, of an organic peroxide (pref. dicumyl peroxide or the like).
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