| 摘要 |
A non-woven fabric suitable for use as a tufted carpet base is prepared by applying a polar lubricant to a non-woven self-bonded fabric comprising randomly disposed continuous filaments of a polymer from the group of isotactic polypropylene, linear polyethylene, linear copolymers of ethylene or propylene with up to 25% by weight of other copolymerizable monomers, and melt blends of said polymers and copolymers with up to 25% of other polymers, e.g. atactic polypropylene, branched polyethylene, polyisobutylene; the filaments possess a birefringence that is at least 40% of the maximum birefringence and the average edge bond count of the fabric, i.e. the number of bonds appearing on an edge face of the fabric per one hundred filaments, lies between 30 and 80. The polar lubricants include methyl hydrogen polysiloxane, 2-ethylhexyl silicate, 2-ethylhexyl sebacate, acetyl 2-ethylhexyl citrate, refined coconut oil potassium oleate, potassium n-octyl phosphates and mixed n-octyl-hydroxy-ethyl esters of phosphoric acid. The lubricants may be applied by spraying, padding, roll coating and in the form of dispersions or solutions in water or an organic medium, and lubricant pickup is usually from 0.3% to 10% by weight of the fabric. The fibrous web may be air-laid and is bonded by exposing the web to a non-solvating fluid, e.g. steam, at a bonding temperature Tx which is within 45 DEG C. below the crystalline melting temperature of the filament while simultaneously applying light compressive forces to the surfaces of the web to prevent shrinkage of the filaments of more than 20% and to prevent loss in birefringence of more than 50%. The bonding temperature Tx is that temperature within the 45 DEG C. range which gives the best tear resistance in the bonded product and is determined for any given material by experiment. The compressive restraint on the sheet is usually maintained till the temperature is at least 5 DEG C. below the bonding temperature. The sheet or web may contain up to 25% of other filamentary materials, such as glass, metal, or other organic or inorganic materials. Minor amounts of fillers, stabilisers, pigments and the like may also be included. The web may be pressed and heated to emboss or otherwise treat its surface after the bonding process. In examples described the fabric was tufted in conventional manner with nylon carpet yarn at a spacing of 4 to 15 stitches per inch with tuft rows at 0.188 inch separation and tuft height of 0.44 inch. The tufting needle diameter may range from 0.1 to 0.18 inch. A latex adhesive may be applied to the back of the tufted carpet and dried to hold the tufts in place or a secondary backing fabric of the same type as the primary fabric but without the polar lubricant, laminated thereto by means of the adhesive layer. |
