Patent GB-553338-A (GB)
Title: Improvements in or relating to moistureproof sheet wrapping material
IPC: C09D101/18
Filed: 1941-08-06
Abstract: 553,338. Coating - compositions. BRITISH CELLOPHANE, Ltd. Aug. 6, 1941, No. 10008. Convention date, Aug. 7, 1940. [Class 95] [Also in Groups IV, V and VIII] A moisture proofing surface coating composition or a composition for forming self-sustaining moisture proof films comprises a wax moisture proofing agent, a halogenated aliphatic hydrocarbon, which contains at least one combined halogen atom for every 15 combined carbon atoms and which is liquid below 35‹ C. and is of low volatility at ordinary room temperature, and a film-forming agent of the class comprising cellulose esters and ethers, artificial resins produced from acrylic acid derivatives, unvulcanized rubber, gutta percha, thermoplastic rubber derivatives of the type known as " Pliolite," chlorinated rubber, and synthetic rubbers such as polymers of isobutadiene and their homologues. The halogenated aliphatic hydrocarbon serves as a blending agent for the wax or waxlike substance. It may be present in sufficient quantity and be of such nature as to serve also as the film-forming agent and in that case, a film-forming agent of the class specified above may be omitted. The waxy substance may be paraffin wax, Japan wax, pale-wax, beeswax, spermaceti, Chinese insect wax, carnauba wax, candelilla wax, or a synthetic wax, e.g. a substance described in Specification 467,901. Mixtures of hard and soft waxes may be used. The halogenated aliphatic hydrocarbon may be a chlorinated paraffin wax, chlorinated petroleum oil, a chlorinated or brominated C 34  H 66  diolefine, e.g. 9: 10: 25 : 26 - tetrachloro - tetratriacontane. Cellulose derivatives which may be used as filmforming substance include ethyl, benzyl, and glycol cellulose ethers, and cellulose acetate and nitrate. A plasticizer may be present in the composition. Specified plasticizers are tricresyl phosphate, dicyclohexyl phthalate, methyl- (dimethyl cyclohexyl) adipate, and butyl benzoyl benzoate. In some cases the halogenated aliphatic hydrocarbon used as blending agent also acts as a plasticizer. Natural or synthetic resins may be added to the other ingredients of the coating composition. Among such resins are rosinates, dammar, copal, kauri, alkyd resins, polyvinyl resins, chlorinated diphenyl resins, soluble phenol-formaldehyde resins. The composition may be applied to non-fibrous sheet wrapping material, e.g. films of regenerated cellulose, cellulose esters or ethers, gelatine, casein, rubber hydrochloride. The composition is preferably applied as a solution in a volatile solvent, e.g. a mixture of ethyl alcohol, ethyl acetate, and toluene. In an example, a regenerated cellulose film is moistureproofed by coating it with a composition comprising ethyl cellulose, paraffin wax, chlorinated paraffin wax, maleic anhydride modified ester gum, toluene, and ethyl alcohol. In another example, the coating composition comprises " Pliolite" resin (a thermoplastic rubber compound obtained by condensing rubber with a catalyst such as tin tetrachloride), paraffin wax, chlorinated paraffin wax, and toluene. In another example, the coating composition comprises chlorinated rubber, paraffin wax, chlorinated paraffin wax, calcium rosinate or lithium rosinate, and toluene. The coated sheets or the films made of the composition are heat-sealable. They may be subjected to a heat treatment to improve the transparency. Specification 283,109, [Class 2 (ii)], also is referred to.