Process for producing hoses of high impermeability to gas and vapor

Claim 1

A process for the production of a hose construction comprising a core tube having a resinous inner wall and a rubbery outer wall, a reinforcement layer disposed around said outer wall, and a cover laminated over said reinforcement layer, which process comprises extruding a resin around a mandrel to form a tubular layer and provide said inner wall having a thickness of not more than 800 μm, said mandrel being formed of an unplasticized or plasticized polymeric or elastomeric material and having a bending strength of 0.2 to 3 kgf, and said plasticized material containing a plasticizer in an amount of not more than 10% by weight, laminating said outer wall over said inner wall, forming said reinforcement layer over said outer wall, and forming said cover of a rubbery material around said reinforcement layers, whereby the hose has high impermeability to gas and to vapor and great flexibility.