Patent GB-541559-A (GB)
Title: Improvements in and relating to moistureproofing compositions and articles coated therewith
IPC: C09D101/18
Filed: 1940-05-30
Abstract: 541,559. Resinous compositions. BRITISH CELLOPHANE, Ltd. May 30, 1940, No. 9523. Convention date, June 1, 1939. [Class 95] [Also in Groups IV and VIII] A moisture-proofing coating composition comprises essentially a film-forming substance, a moisture-proofing substance and a resinous polyhydric alcohol ester of a synthetic terpinene-maleic anhydride polybasic acid resin complex, known as " isopropyl " acid and comprising essentially 3-isopropyl-6-methyl-3: 6- endoethylene-delta-4-tetrahydro-phthalic anhydride. Preferably, the film-forming substance is nitrocellulose or a mixture of nitrocellulose and butyl methacrylate or other resin. Instead of nitrocellulose there may be used another cellulose derivative, or a natural or synthetic resin. The moisture-proofing substance may be paraffin wax, petroleum, ceresin, Japan wax, palm wax, beeswax, chlorinated hydrocarbons, Chinese insect wax, or other natural or synthetic wax or wax-like substance. Soft waxes may be mixed with harder waxes such as carnauba, or candelilla. The nitrocellulose may be mixed with resins such as dammar, copal, kauri, rosinates, polyhydric alcohol-polybasic acid resinous condensation products, vinyl derivatives, chlorinated diphenyl resins, or soluble phenol-formaldehyde resins. The coating composition may be applied to sheets or films of regenerated cellulose, whether made by the viscose, cuprammonium or other process, or to sheets or films of cellulose ethers such as ethyl, benzyl, or glycol cellulose, cellulose esters such as cellulose nitrate or cellulose acetate, or to gelatine, or casein. The amount of nitrocellulose in the composition may comprise 30-70 per cent. of the total solids. A plasticizer may be present. Glycol, glycerol, diethylene glycol, triethylene glycol, tetraethylene glycol, n-butylene glycol, isobutylene glycol, and propylene glycol esters of " isopropyl " acid or mixed esters thereof may be used, and they may be fully or partially esterified products. In examples, the compositions contain in addition to nitrocellulose and an ester of " isopropyl " acid, paraffin wax, dibutyl phthalate, dicyclo-hexyl phthalate, ethyl acetate. toluene, ethyl alcohol, wax-free dammar resin, and modified rosin. In one example, there is used the mixed ester ethylene-diethylene-triethylene glycol " isopropyl." The coating compositions are applied to regenerated cellulose films softened with glycerol. They give heat seal 'bonds of high strength. The coated films are of use in packing cereals, nuts, and other foods. They may be formed into transparent bags. The " modified rosin" which may be present in the composition is obtained by dissolving rosin in gasoline in about equal parts, adding slowly a strong solution of sulphuric acid while agitating and cooling, allowing the mixture to settle after the re-action has ceased, separating the acid portion and distilling the gasoline portion to remove the gasoline and obtain rosin, free or combined, of improved colour and higher melting point. Specifications 283,109, [Class 95], and 446,383, [Group IV], are referred to.