| 摘要 |
813,863. Coated regenerated cellulose films. BRITISH CELLOPHANE Ltd. Nov. 15, 1957 [Dec 7, 1956]. No. 37493/56. Class 140. A semi-moistureproof sheet wrapping material comprises a regenerated cellulose film coated on at least one side with a continuous unbroken surface coating of a composition capable of rendering the film permeable to water vapour such that the film has a permeability value of 1500 to 7000 at 40‹ C and 500 to 2500 at 20 ‹ C.. the coating being anchored to the film by means of an anchoring agent and the film containing as a softening agent a polyalkylene oxide of molecular weight between 106 and 600 and a solubility in water of at least 4 per cent by weight at 25‹ C. present in the film within the range 5 to 30 per cent by weight of the combined weight of the cellulose and softening agent. The polyalkylene oxide is formed by the polymerization of an alkylene oxide, e.g. ethylene, propylene or butylene oxide, and may be mixed with another softening agent e.g. glycerine or urea. The anchoring agent may be a cationic urea-formaldehyde resin, polyalkylene imine, vinyl chloride-maleic anhydride copolymer, or a melamine-formaldehyde resin. The coating composition may be that disclosed in Specifications 664,248, 756,346 or 768,571. U.S.A. Specification 2,328,679 also is referred to. |
