Flexible partition member for hydraulic accumulator, including ethylene-vinyl alcohol copolymer gas-barrier layer and polyamide resin elastic layer

A hydraulic accumulator having a shell and a partition member that is disposed in said shell and that divides an interior of said shell into two sections that provide a gas chamber and a liquid chamber, respectively, said partition member comprising:

• an integrally laminated composite portion comprising two adjacent layers that consist of (i) a gas-barrier layer consisting of a copolymer of ethylene and vinyl alcohol, and (ii) an elastic layer consisting essentially of a polyamide resin and a polyolefin material, said polyamide resin being present in an amount of at least 50% by weight of said elastic layer and being selected from the group consisting of nylon 6, nylon 66, nylon 6-10 and nylon 6-12, and said polyolefin material being present to prevent the copolymer of ethylene and vinyl alcohol in said gas-barrier layer from absorbing an aqueous hydraulic fluid component as opposed to an elastic layer without said polyolefin material;
• and
• a rubber layer bonded to each of opposite outer surfaces of said integrally laminated composite portion.