| 摘要 |
<p>1427040 Coated fabrics E I DU PONT DE NEMOURS & CO 16 Feb 1973 [16 Feb 1972] 7769/73 Heading B2E [Also in Division B5] A bonded non-woven fabric suitable for use as a backing for a tufted pile carpet which is coated with a latex after tufting, is composed of filaments of isotactic polypropylene which are of two types and/or of both types as alternating segments in the same filament, namely matrix fibres which have an average denier of at least 12 and an average tenacity of at least 2.5 grains per denier and binder fibres which have a lower orientation and a lower softening point than the matrix fibres and through meltbonding of which the filaments are bonded together, the fabric comprising a machine direction (MD) layer on at least one surface of the fabric, in which MD layer the filaments 2 are disposed generally in the machine direction of the fabric, and a cross-machine direction (XD) layer in which the filaments 1 are disposed generally in the cross-machine direction, each of the layers constituting 40-60% of the total fabric weight and consisting of 82-50% by weight of matrix fibres and 18-50% by weight of binder fibres, the MD layer having an MD L / XD L of at least 3.0, the XD layer having an XD L /MD L of at least 3.0 and the fabric having an MD/45‹ of at least 1.5, an XD/45‹ of at least 1.5 and an (MD+XD)/45‹ of 3.5-30, in which MD L /XD L , XD L /MD L , MD/45‹, XD/ 45‹ and (MD+XD)/45‹ are directionality values representing the relative properties of the filaments aligned in specified directions by the randometer method, The fabric may be produced by forming the MD layer or XD layer by depositing suitable filaments which may be electrostatically charged onto a moving surface by means of a plurality of pneumatically oscillated gas streams which forward the filaments, forming the other layer on top of the first layer in the same way and heating the structure comprising the MD and XD layers while restraining it under conditions such that melt-bonding of the binder fibres takes place, preferably by passage through saturated steam. A polysiloxane finish may be applied after bonding filaments having segments of matrix fibres and binder fibres may be produced by stretching the extruded filaments over rolls one of which is a heated fluted roll having grooves running along its surface in the axial direction so that segments of the filaments which touch the hot surface of the roll between grooves are drawn additionally but those segments suspended over the grooved portions are not drawn additionally. In an alternative arrangement extruded filaments may be divided into two streams one of which is passed over additional rolls as compared with the other before they are combined to form a single group. After tufting to form a carpet, a latex comprising 3 parts by weight of elastomer particles of 60% by weight of styrene and 40% by weight of butadiene and 1 part by weight of elastomer particles of 40% by weight of styrene and 60% by weight of butadiene may be applied by roller coating to the backing.</p> |
