GB532673A - Improvements in or relating to the production of acidyl derivatives of cellulose and other organic substances - Google Patents

Abstract

532,673. Cellulose derivatives ; resinous condensation &c. products ; albumens ; artificial silk. MONCRIEFF, R. W., BATES, H., and DREYFUS, H. July 18, 1939, Nos. 20825 and 20827. Divided out of 532,674. [Classes 2 (ii) and 2 (iii)] [Also in Group VIII] Formed articles such as yarns, fibres or foils having a basis of a cellulosic or other organic substance containing hydroxy or -NH- groups are acidylated by heating them in a medium containing a mixed anhydride of succinic, adipic, tartaric, or phthalic acid and a lower mono-carboxylic acid under such conditions that their form is retained. The mixed anhydride may be obtained by heating a mixture of the dicarboxylic acid anhydride and a lower monocarboxylic acid or ester thereof, or a mixture of a lower monocarboxylic acid anhydride and the dicarboxylic acid or an ester thereof. Free acid may be removed from the heated mixture by distillation or by passing ketene through the mixture, or by adding a base such as pyridine or calcium, barium, or strontium oxide. Acetic, propionic, butyric, methoxy-acetic, ethoxyacetic, or a chloracetic acid may be used as the monocarboxylic acid. The process is applicable to the treatment of yarns and other formed articles having a basis of wool, casein, polyamides, partially saponified polyvinyl esters, e.g. vinyl chloride-vinyl acetate co-polymers, regenerated cellulose including that obtained from the viscose, cuprammonium, or nitrocellulose process or from the saponification of cellulose esters, or having a basis of cellulose derivatives such as cellulose acetate or other cellulose ester or ether. Acidylation may be effected in the presence of catalysts such as ferric, zinc, or stannic chloride. Diluents such as kerosene, xylene, mixtures of xylene and paraffin wax, anthracene, naphthalene, or odichlorobenzene may be present. In an example, a warp-knitted cellulose acetate fabric is heated with a boiling solution of a mixed anhydride obtained by heating adipic acid with acetic anhydride, driving off free acetic acid and dissolving the residue in a mixture of xylene and o-dichlorobenzene. The fabric is subsequently washed in boiling carbon tetrachloride. In other examples, cellulose acetate fabric is heated with a mixed anhydride of phthalic acid or tartaric acid and acetic acid dissolved in kerosene. The treated fabrics are water-resistant and have a higher melting point and safe ironing temperature than before the treatment. They are insoluble in most solvents. Prior to the acidylation they may be scoured and dry cleaned to remove lubricant. The Provisional Specifications describe also the acidylation of cotton linters for the production of cellulose derivatives which can be dissolved in organic solvents and formed into filaments, foils, lacquers or other products. Esterification may be effected in presence of a solvent for the cellulose derivative produced.