Tube for use as cooling water tube for motor vehicle radiators - comprises inner layer of peroxide-vulcanised ethylene-propylene rubber contg. silica and outer layer of peroxide-vulcanised acrylate rubber

摘要

The tube comprises (A) an inner layer suitable for contact with hot aq. fluid and (B) an outer rubber layer suitable for contact with hot air bonded together by vulcanisation. (A) contains ethylene-propylene rubber (I) vulcanisate, (B) contains acrylic rubber (II) vulcanisate. (I) and (II) are peroxide-vulcanised, and outer surface of (A) in contact with (B) contains (I) contg. SiO2. Pref. (I) contains 45-95 % ethylene units. (I) is ethylene-propylene-nonconjugated diene copolymer (III). (I) contains 95-65 % (III) with Mooney viscosity ML1+4 (100 deg.C) 20-100 and 5-35 % (III) with ML1+4 (100 deg.C) 200 or more. (I) also contains allyl co-crosslinking agent. (II) contains 3-10 % ethylene and 70-90 % acrylate ester monomer units. (II) also contains 0.12-0.30 % epoxide-contg. crosslinkable monomer. ADVANTAGE - (A) resists hot water and glycol, (B) has good resistance to heat and oil, and (I) has good bonding between (A) and (B).