| 摘要 |
Curable flurooelastomeric compositions used for O-rings com- prising: A) 100 parts (phr) of a curable fluoroelastomeric co- polymer having a content in F< 6701 by weight and com- prising from 40 to 68% by weight of VDF units, from 20 to 50% by weight of HFP units, the sum being 100, and optionally one or more comonomers having ethylene unsa- turation, said copolymer having a number of ionic ter- minals of at least 0.5 for chain; B) from 1 to 5 phr of an adduct between an accelerator and a curing agent in molar ratio from 1:3 to 1:5, the accelerator being an onio-organic compound having a positive charge, the curing agent being a di- or poly- hydroxy or di- or polythiol compound; the adduct being obtained by melting of the reaction product between accelerator and curing agent in the indicated molar ratios, or by melting of the adduct mixture 1:1 added with the curing agent in the indicated amounts.
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