GB545466A - Improvements in and relating to the manufacture and production of softened pellicles, films, sheets, and like materials - Google Patents

Abstract

545,466. Films; paper. BRITISH CELLOPHANE, Ltd. Nov. 25, 1940, No. 16917. Convention date, Jan. 20. [Class 2 (ii)] [Also in Group VIII] Non-fibrous cellulosic pellicles of the type which includes sheets, artificial straws, and continuous tubes are treated with a softening agent, which has a tendency to cause discoloration with age, and a reducing agent, the molecule of which contains at least one sulphur atom joined directly to an oxygen atom. The reducing agent prevents the softened material from becoming discoloured. The softening agent may be glycerol, diethylene glycol, sorbitol, mono-ethanolamine formate, monoethanolamine hydrochloride, mono-ethanolamine sulphamate, di-ethanolamine addition products, tri-ethanolamine addition products, ethanolamine formamide, or urea. The reducing agent may be sodium sulphite, sodium hydrosulphite, amino-imino-methane sulphoxylic acid, acid or neutral salts of sulphurous acid, esters or salts particularly alkali metal or alkaline earth metal salts of aminoimino sulphoxylic acid, sodium sulphoxylate, or a thiosulphate. The softener and reducing agent may be applied simultaneously to the film or sheet. They may be applied as an aqueous solution or dispersion. Films may be treated in the gel state during the process of manufacture before the first drying. The pellicles may be of cellulose regenerated from .viscose or cuprammonium-cellulose solutions, or of a water- or alkali-soluble cellulose derivative such as glycol cellulose, cellulose glycollic acid, alkyl cellulose, or similar lowly esterified or etherified cellulosic material. In an example, regenerated cellulose film in the gel state is passed through a solution of ethanolamine hydrochloride containing a small amount of magnesium sulphite. The treated materials may be used for wrapping purposes. Specification 211,446, [Class 2 (ii)], is referred to. The Specification, as open to inspection under Sect. 91 comprises also the treatment of paper, especially of the glassine type, and of films of gelatine, casein, and the like. This subjectmatter does not appear in the Specification as accepted.