FABRIC MATERIAL

Abstract: A woven fabric material is formed from tapes of synthetic resinous material such as polypropylene, either the warp tapes or the weft tapes having discontinuous longitudinally extend­ ing localised weakened areas formed in them, for example dis­ continuous longitudinally extending grooves in the tapes. The woven fabric is then stretched by stretching longitudinally and at a raised temperature that set of warp tapes or weft tapes which does not have the weakened areas, thereby causing the tapes with the weakened areas to split at those areas and open up to take on the appearance of a network. The stretched woven fabric material is cooled in the stretched condition so that the final stretched woven fabric material obtained has a substantially greater area and a lesser overall thickness than the base woven fabric, i.e. the fabric before it was streched.

Description: FABRIC MATERIAL The present invention relates to fabric materials and particularly to woven fabric materials including tapes of stretchable synthetic resinous material. The present invention is an improvement in and modification of one aspect of the invention disclosed in our co-pending European Patent Application No. 82.3036322. In the said co-pending patent application there is disclosed in relation to Figures 1 and 2 a woven construction formed from flat polypropylene tapes which constitute both the warp and weft elements of a base fabric material. The weft tapes are produced with longitudinal zones of weakness which are localised weakened areas extending longitudinally in each weft tape before the tape is woven into the base fabric material. After weaving these weft tapes with longitudinally extendable warp tapes the woven fabric material is heated to a temperature at which the synthetic resinous material becomes softened, and is tensioned in the warp direction to stretch the fabric in the warp direction to approximately twice its original length. As the heated warp tapes are stretched and extend longitudinally they interact on the weft tapes with which they are in frictional contact so that the weft tapes tend to split, either continuously or intermittently, along the weakened areas or zones into strips which are pulled apart. When the degree of stretch of the warp tape is sufficient, each longitudinally weakened weft tape splits into a series of narrow strips so that the number of weft tapes in the fabric is multiplied. On subsequent cooling of the stretched fabric under tension, the warp tapes bond to the subdivided weft tapes at the intersections to give a final product which is a stretched fabric with a high degree of dimensional stability. Instead of providing continuous longitudinally extending localised weakened areas, for example continuous grooves extending longitudinally in the weft tape, the method according to the present invention provides for the formation of discontinuous longitudinally extending localised weakened areas in each weft tape. The discontinuous longitudinally extending localised weakened areas may be arranged in groups of such areas with untreated portions of the tape between each group. Alternatively the discontinuous longitudinally extending localised weakened areas may be staggered so that most, if nowt all, of the length of the tape has one or more longitudinally extending area of laterally localised weakening within it. When a woven fabric with weft tapes having discontinuous longitudinally extending localised weakened areas is heated and stretched under tension in the warp direction, the weft tapes tend to split at these discontinuous weakened areas so that each weft tape is broken down into a series of interconnected strips. The strips are pulled apart from one another by frictional contact with the warp tapes so that each weft tape takes on the appearance of a network, which may be regular or irregular depending on the arrangement of the discontinuous weakened areas in the original weft tape. If the-degree of stretch of the warp tapes is very high, the splits formed at the discontinuous weakened areas may be propagated lengthwise so that substantial lengths, and possibly the whole length, of the weft tapes are subdivided into separate weft tapes. The treatment of the woven fabric formed with weft tapes as described is carried out substantially as described in our said co-pending European Patent Application No. 82.3036322 and the resulting product has similar advantages to those described for the product of the said co-pending patent application, including greater tenacity of the fabric (in grammes/dtex) in the warp direction, greater area of fabric for a given quantity of material, and good dimensional stability of the fabric when stretching of the fabric is undertaken under conditions permittingbondingof the warp and weft tapes at their intersections. Instead of using the tapes with the discontinuous longitudinally extending localised weakened areas as weft tapes, they may be used as warp tapes in a fabric which is stretched transversely instead of longitudinally.

Claims: CLAIMS: 1. A method of manufacturing a fabric material comprising the steps of forming a woven base fabric of warp and weft tapes, stretching the base fabric to stretch longitudinally either the warp or the weft tapes and thereby obtain a stretched fabric having greater area than the original base fabric, characterised in that the other of the warp and weft tapes include discontinuous longitudinally extending zones of weakness and that, during stretching, at least some of the other tapes split at the zones of weakness. 2. A method accord-ing to Claim 1, characterised in that the weft tapes include discontinuous longitudinally extending localised weakened areas.

Inventors: TOUGH, WILLIAM HAMISH
Applicants: SCOTT & FYFE LIMITED
Application year: 1984
Main classification: D03D15
IPC codes: D03D15