GB1506389A - Production of fabrics - Google Patents

Abstract

1506389 Finishing fabrics; knitted fabrics; testing fabrics IMPERIAL CHEMICAL INDUSTRIES Ltd 3 April 1975 [10 April 1974] 15875/74 Headings D1K and D1S A fabric suitable for moulding and which has an area stretch of at least 450%, preferably 500 - 900%, is produced by weft knitting, on a machine capable of making single jersey constructions, a single jersey precurser fabric under conditions giving essentially maximum loop length to the fabric stitches and minimum yarn tension, from shrinkable, unstabilised or partly stabilised bulked or potentially bulkable continuous homofilament yarn of polyester and/ or nylon such that the precursor fabric has an area stretch of at least 100%, preferably 100 - 200%, a weight in the range of 20 to 80 grams per square metre and percentage light transmission in the range of 50 to 90, these weight and light transmission properties lying within the area ABCD of Fig. 1, and subjecting the precursor fabric to a tumble bulking treatment of elevated temperature whereby it relaxes to its fullest potential. Preferably, the fabric is fed into a cool tumble dryer, the temperature is raised to the required level and the fabric is allowed to cool before being removed. The fabric is fed into the tumble dryer in such a manner that the length direction of the fabric coincides with the motion of the machine. Suitable yarns have a decitex of 30 - 200, preferably 50 - 170, are those of which the bulk has not been fully developed, e.g. yarns made by false-twisting and knit-de-knit processes. The weft-knitted fabric may be made on a flat bed or circular machine with a low knitting tension and a large stitch length. Preferably, combinations of Z- and S-twist yarns are used. Optionally, the fabric is stentered and, if tubular, slit and an adhesive selvedge applied. Before moulding, the fabric may be coated with polyvinyl chloride to produce an upholstery fabric. Resinous and plastisol finishes e.g. polyethylene or acrylic resins, may be applied to the side of the fabric to be placed against the mould surface to aid shape retention of the moulded fabric. Apparatus for measuring the light transmission of the fabric, before tumbling, Fig. 2, comprises a rectangular box divided into three compartments 3a, 3b, 3c of which the compartment 3b contains a light sensitive cell 4 shielded by a tube 9 and the compartment 3c a "bridge" circuit A powered by a source 1 which also energises a projector bulb 2. The filament of the bulb 2 is on the common horizontal axis of .the centres of apertures 6, 7. In use, a fabric sample to be tested is mounted on a pin frame which is then mounted in a slot 8 between the compartments 3a, 3b. The light is switched on and the reading on a microammeter 5 noted. Te sample is removed and the meter reading is taken with the bulb light and no fabric to give a reading corresponding to 100% light transmission. Meter readings are taken using neutral density filters of known light transmission. A calibration graph is plotted from which the light transmission of the fabric can be deduced.