| 摘要 |
<p>1494059 Non - woven fabric SCOTT PAPER CO 23 Feb 1976 [13 March 1975] 07109/76 Heading D1R A method of forming a bulky, flexible, stretchable nonwoven fibrous sheet comprises dry-forming a low integrity fibrous web having a basis wt. of 5 to 100 lbs/2880 sq. ft., bonding the fibres with a brittle, temporary binder to allow subsequent processing, applying a permanent binder to one or both surfaces of the temporarily bonded web (in a solids wt. per cent of 5 to 30, based on the dry wt. of the temporarily bonded web) in a pattern covering 5 to 60% of the area of the said surface(s) and extending at least 10% through the thickness of the web; adhering to a creping surface 48 the areas of the web to which the permanent binder has been applied; creping the web and thereby breaking the bonds formed by the brittle temporary binder to cause the non permanently bonded areas 62 to bulk. As shown the web is formed from three corded layers of fibres of length “ inch to 3 inch, selected from cotton, rayon, polyolefin, polyester, cellulose acetate, acrylic or polyamide. Garnetts may replace the cording machines 10. Alternatively wood pulp or cotton linter fibre of less than “ inch length may be air laid, optionally mixed with textile length fibres. The temporary binder is preferably starch. Alternatively dextrin, animal glue, gum, casein, carboxymethyl cellulose, urea-formaldehyde resin, polyacrylate, polyamide, polyvinyl alcohol or a polyvinyl alcohol/polyvinyl acetate copolymer may be used. It may be sprayed, padded or coated onto one or both web surfaces, or mixed in powder form with the fibresduring web formation and activated with moisture. As shown an aqueous dispersion of starch is applied by lower roll 22 of a bonding nip and the water is removed by dryer cans 32. The permanent binder is an emulsion or dispersion of polymers or copolymers of ethylene, vinyl acetate, acrylate, styrene, butadiene, vinyl chloride or vinylidene chloride. A latex dispersion of ethylene/vinyl acetate copolymer is preferred. It is applied by gravure roll 38. Creping drum 48 rotates at a circumferential speed of 105 to 150% of the take-up roll. Both sides of the web can be printed with permanent binder and then creped. The web is heated by cans 56 to remove moisture and cure the binder if a curable binder is used.</p> |
