SUBSTANTIALLY CLOSED FABRIC MADE BY COMPRESSIVE REDISTRIBUTION OF THE FILAMENTS OF AT LEAST SOME YARNS OF AN OPEN MESH FABRIC

摘要

1463969 Closed mesh fabrics; hot pressing fabrics to reduce the open area BAY MILLS Ltd 28 April 1975 [26 April 1974] 17465/75 Headings D1K D1R and D1S A "closed" fabric having an open area of not more than 35% of the area of the fabric is formed by compressing a woven or non- woven fabric having an open area of at least 70%, the starting fabric comprising at least one layer of warp yarns constituting a first group of yarns and at least one layer of fill yarns arranged at an angle to the warp yarns and constituting a second group of yarns, the yarns of both groups having a coating of at least 5% by weight of a thermoplastic material of lower softening point than that of the yarns, the denier per inch of at least one group of yarns being at least 4000 and the yarns of at least this group each containing at least 20 filaments and having 0 to 1 turns per inch of twist. Preferably the starting fabric comprises three superposed arrays of parallel yarns, the yarns of one array being perpendicular to those of the other arrays, the yarns being identical and all having the properties specified above. The filaments may be rayon, nylon, polyester, polypropylene or glass. Each yarn may have a denier of at least 200. In the example three layers of 7¢ polyester yarns/inch, each yarn being of 1000 denier, 192 filaments, having 0.035 turns per inch and a 53% by weight polyvinyl chloride coating formed a fabric which was 48% open. It was passed at 18 ft./minute over preheating roll 18 at 260‹F then between the nip formed by steel roll 15 at 360‹F and cotton roll 16 which was maintained at 160‹F by coating roll 17. The heat and pressure soften the polyvinyl chloride so that the yarns are flattened. The fabric is maintained in contact with roll 16 long enough for the polyvinyl chloride to harden and thus bind the filaments in their new positions. The open area of the fabric is reduced by 96% and its thickness by 56%. The coating may alternatively be polyvinyl acetate or low melting polyester.