GAS IMPERMEABLE ELASTIC MEMBRANE AND HYDRO-PNEUMATIC ACCUMULATOR PROVIDED WITH THE MEMBRANE

摘要

PROBLEM TO BE SOLVED: To provide high stability against aging at high temperature by forming a membrane constituted of two layers of copolymer containing polyamido block and polyether block between which a film of gas impermeable copolymer containing OH-group is built in, and arranging rubber coatings on the layers so as to form an elastic membrane. ;SOLUTION: A film 1 of hard material which is impermeable against gas and the like, particularly, nitrogen, is inserted between two layers 2, 3 made of material of refractivity and elasticity. The gas impermeable material is partially crystalline copolymer containing OH-group, and it is favorable to use EVOH. EVOH is essentially copolymer consisting of ethylene and vinyl alcohol units. The layers 2, 3 are desirable to contain rubber coatings 4, 5. The role of the rubber is to give working liquid resistance and give the membrane leaktightness. The elastic membrane is relatively easily stored, it can be packed, and it provides favorable aging resistance under the condition of high temperature.;COPYRIGHT: (C)1998,JPO