Patent ID: 7413804

Claim:
A method of coating a polymeric resinous thin film having a predetermined thickness on a surface of a tubular braid reinforcing material, said polymer resinous thin film consisting of two layers, a single skin layer with micro pores having a diameter in the range from 0.01 to 1 μm and a single inner layer of a sponge structure with micro pores having a diameter less than 10 μm, the method comprising: spin coating a polymeric resinous coating material including a polymer resin, an organic solvent polyvinylpyrollidone and a hydrophilic compound on the surface of the tubular braid, extruding it into the air, and coagulating the coating material in a coagulating bath, wherein the ration (k) of the spin coating feed rate (Q) and the braid advancing speed (v) with respect to a unit outer diameter (D O ) of the braid as represented by the formula k ⁡ ( g ⁢ / ⁢ m 2 ) = Q ⁡ ( g ⁢ / ⁢ min ) v ⁡ ( m ⁢ / ⁢ min ) ⁢ D 0 ⁡ ( m ) falls within the range of 200 to 3,000 g/m 2 .