Patent GB-782455-A (GB)
Title: Manufacture of moisture-resistant coated films of regenerated cellulose
IPC: C08J7/052
Filed: 1955-03-30
Abstract: A regenerated cellulose film is impregnated with a water-soluble reaction product of phosphorus oxychloride, or phosphorus thiotrichloride, with an alkylene imine, or with a mixture of an alkylene imine and a subordinate amount of a secondary aliphatic amine, and subsequently coated with a moisture-resistant, preferably heat-sealing coating.  For impregnation, the reaction product may be added to an aqueous bath, preferably the softening bath used in the treatment of the film during manufacture, or the dried film may be treated with a solution of the reaction product in, e.g. ethyl or methyl alcohol. The reaction products may be monomers or low-degree polymers. The monomer is prepared by reacting the phosphorus compound with, e.g. ethylene imine, with or without dimethyl- or diethyl-amine, in the ratio 1 mol. amine to 2 mol. imine per atom of phosphorus present, in the presence of an acid-binding agent, e.g. ammonia, or trimethyl- or triethyl-amine, in, e.g. chloroform, benzene, toluene or chlorobenzene as solvent.  Polymerization is effected by heating at up to 100 DEG  C., or by catalysts, e.g. sulphuric, sulphurous, or carbonic acid, dimethyl-, diethyl-, dipropyl-, or dibutyl-sulphate, the methyl or ethyl ester of p-toluene sulphonic acid, or water, and solvents, e.g. benzene, toluene or xylene, may or may not be present.  The polymer is precipitated by dilution with, e.g. benzene, toluene or acetone. Mixtures of reaction products may be used.  An acid or acid-reacting salt may be added to the impregnation bath or the film may be treated before or after impregnation with an acid or acid-reacting salt, e.g. boric, lactic, glycollic, citric, gallic, succinic or maleic acid or monosodium or monopotassium phosphates.  In examples: (1) film is passed through an aqueous softening bath containing glycerol and a polymerized product of phosphorus oxychloride and ethylene imine, dried, and coated with a composition containing nitrocellulose, dibutyl- and dicyclohexyl-phthalates, modified phthalate resin, urethane-formaldehyde resin, and paraffin wax dissolved in 1/1 ethyl acetate-benzene; (4) dried film before coating with the composition of (1) is passed through an ethyl alcohol solution of equal parts of the polymerized reaction product of phosphorus oxychloride and ethylene imine and the monomer reaction product of phosphorus thiotrichloride and ethylene imine; (5) film before coating as in (1) is passed through an aqueous softening bath containing ethylene glycol, the reaction product of (1) and gallic acid.ALSO:The monomer reaction products of phosphorus oxychloride or phosphorus thiotrichloride with an alkylene imine or with a mixture of an alkylene imine with a subordinate amount of a secondary aliphatic amine may be used to impregnate regenerated cellulose film before coating with a moisture-proofing coating. The monomer is prepared by reacting the phosphorus compound with e.g. ethylene imine with or without dimethyl- or diethyl-amine, in the ratio 1 mol. amine to 2 mols. imine per atom of phosphorus present, in the presence of an acid-binding agent, e.g. ammonia, or trimethyl-, or triethyl-amine, in e.g. chloroform, benzene, toluene, or chlorobenzene as solvent.