Fibrous sheet material and method and apparatus for forming same

Abstract

Abstract 1294794 Bonded creped sheet material; spot bonded fabric; paper - making apparatus SCOTT PAPER CO 19 April 1971 [13 April 1970] 25797/71 Headings D1L D1R D2A and D2B A fibrous sheet material having a basis wt. of 6-60 1b. per 2880 sq. ft. and having a pattern of raised areas and depressions on each of its surfaces has a bonding material disposed in the raised areas on one side of the sheet, the raised surfaces of the bonded areas being finely creped to impart softness. Web formation. The bonded, creped sheet may be formed from a web formed by depositing fibres on a foraminous screen by an airlaying or wet-laying method. The fibrous material may be short cellulosic fibres, or a blend of relatively short and long fibres, the latter being cotton, wool, regenerated cellulose, e.g. rayon, cellulose ester, e.g. cellulose acetate, polyamide, polyester, vinyl, acrylic, protein, fluorocarbon, nitrile, or dinitrile fibres. The fibrous material may be treated with conventional wet strength additives, e.g. urea-formaldehyde resins, or chemical debonding agents, e.g. cationic surface active agents before or after formation of the web but prior to drying thereof. The web is preferably formed under conditions of little or no pressing while it is wet until substantially dry, and may be creped prior to application of the bonding material. Bonding and shaping web. In a typical embodiment, see Fig. 2, the web 19 is fed between a smooth rubber press roll 23 and a patterned metal rotogravure roll 24 which dips into a pan 25 containing bonding material. The bonding material, which may be applied in a spotted or reticular pattern, Figs. 4, 5 (not shown), may be an acrylate latex rubber emulsion; an acrylate, methacrylate, vinyl acetate, vinyl chloride emulsion; a mixture of glue, urea-formaldehyde resin and polyethylene oxide, carboxymethyl cellulose, polyvinyl alcohol, polyacrylamide, or dextrin, or a.mixture thereof. The treated web issuing from between rolls 23, 24 is passed around a rotatable creping drum 27 and removed therefrom by creping blade 28, which causes unbonded web portions to puff and arch up. The web is then passed through calender rolls 30, 31 and wound into a roll 32. In a modification, Fig. 3 (not shown), the metal rotogravure roll, together with its pan containing bonding material, is arranged directly beneath the creping drum so that the bonding material is applied to the surface of the drum and transferred therefrom to the web. Paper-making apparatus. A paper-making machine, see Fig. 1, which may be used to form the web comprises headbox 10 having a slice 11, a foraminous wire 12, a carrying member 15, which may be either a wire or a felt, a drying drum 21, and creping blade 22. The wet web may be transferred to the carrying member with the aid of a pick up roll 17 provided with vacuum box 20, or air knife 18.

Inventors

No inventors recorded.

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