Patent ID: 6660339
Filing Date: 2003-12-09
Classification: C23C

Abstract:
A process of providing hydrophobicity of a degree such that a static water contact angle of more than 95Â° is achieved on the surface of a water vapour permeable substrate by coating said substrate with a fluro-monomer while maintaining the water vapor permeability of said substrate said process being carried out in a vacuum chamber containing: (i) a support movable from a first to a second position, (ii) a vaporizer comprising an inlet and a vapor outlet said outlet being adjacent to said support when said support is at said first position, (iii) curing means at a second downstream position of said support, and (iv) means for maintaining said support at a temperature below that of said vaporizer; said process comprising the steps of(a) placing said substrate in thermal contact with said movable support in a manner permitting the surface of said substrate to move sequentially past said vapor outlet and said curing means; (b) maintaining said substrate at a temperature below the vaporising temperature of said fluro-monomer; (c) evacuating gas from said chamber until the pressure within said chamber is less than 1.35 Pa; (d) selecting a curable fluoro-monomer component, having an average molecular weight between 150 and 1000 Atomic Mass Units, and a vapor pressure such that it condenses at said temperature and said pressure on said substrate surface; (e) metering a quantity of said curable component into said inlet of said vaporizer; (f) vaporizing said curable component within said vaporizer and exhausting the vaporized curable component through said vapor outlet; (g) moving said support with said substrate past said vapor outlet and said curing means from said first to said second position at a rate of more than 1 cm/sec; (h) condensing a film of said monomer component on the surface of said substrate to a thickness of less than 5 &mgr;m; while moving said substrate past said vapor outlet; (i) crosslinking said condensed monomer film while moving said substrate past said curing means, preferably throughout said thickness of said film.