| 摘要 |
1,243,636. Olefin copolymer elastomer compositions. IMPERIAL METAL INDUSTRIES (KYNOCH) Ltd., and D. A. SMITH. 10 Dec., 1968 [29 Dec., 1967], No. 59194/67. Heading C3P. [Also in Division F3] The lining of a case-bonded solid propellant rocket motor comprises an elastomeric-containing compound including 100 parts of elastomer, 40-100 parts of filler material, and 20-80 parts by weight of at least one chemical compound compatible with the other contents of the elastomer-containing compound and having a temperature of endothermic decomposition above the temperature of the initial decomposition of the elastomer. In a typical embodiment, the 100 parts of elastomer consists of 75-100 parts of a terpolymer of ethylene and propylene and a diene containing unsaturated linkages of unequal reactivity (e.g. Shell ECP 900) and 25-0 parts of a chlorosulphonated polyethylene (e.g. Hypalon 40). The filler material is SiO 2 powder. Either Ca(OH) 2 or Mg(OH) 2 may be used as the chemical compound, both having an endothermic heat of decomposition in excess of that of the elastomer. Heat is absorbed by the chemical compound, thus reducing the temperature of the liner and thereby the rate of loss of the elastomer content itself. The abovedescribed terpolymer results in a low density liner but if density is relatively unimportant, other elastomers such as nitrile rubbers, chlorosulphonated polyethylene rubbers, styrene-butadiene rubbers, butyl rubbers, polyisopropene rubbers, ethylene-propylene copolymer rubbers, and silicone rubbers may be used. |
