GB550620A - Improvements in or relating to moistureproof sheets or films and methods of producing the same - Google Patents

Abstract

550,620. Resinous condensation products. BRITISH CELLOPHANE, Ltd. July 10, 1941, No. 8742. Convention date, July 11, 1940. [Class 2 (iii)] [Also in Group VIII] Moisture-proof coatings for sheets or films made of regenerated cellulose, cellulose esters and ethers, gelatine, polyvinyl resins, rubber hydrochloride, &c. comprise a urea-formaldehyde-monohydric alcohol resin condensed by heat to the hardened insoluble form and a wax moisture proofing agent. The resins may be prepared by condensation of the ethers of dimethylol urea, e.g. as described in Specification 483,399 or the monomeric crystalline dimethylol urea ether may be used as such or in partly polymerized form and condensed in situ byheating the film, if desired, with the addition of .an acid condensing agent, e.g. maleic acid. Resins derived from higher alkyl ethers, e.g. lauryl or octyl ethers, are preferred. Waxes specified are paraffin wax, or monohydric esters of higher fatty acids having a m.p. above 50‹C. The heat-sealing properties of the film are improved by the addition of amides, e.g. diphenyl lauramide, dimethyl-benzoyl benzamide, acetanilide ; blown oils, ester gums, maleic anhydride modified rosins and estergums, methylabietate, resins, and gums may also be added. The compositions may be applied dissolved in mixtures of solvents, e.g. toluene, ethyl acetate, isobutyl alcohol or n-butyl alcohol. In example regenerated cellulose sheeting is coated with a composition comprising urea-formaldehyde-isobutanol resin, paraffin wax, blonde shellac, gum dammar, isobutyl alcohol, toluene and ethyl acetate. Other components specified in the examples are : rosin modified by treatment with H 2 SO 4 , as described in U.S.A. Specification 2,017,866, hydrogenated methyl abietate, non-drying oil modified glycerol-phthalic anhydride resin, sebacic acid modified alkyd resin, dibutyl phthalate and n-butyl alcohol.