GB532674A - Improvements in or relating to the production of acidyl derivatives of cellulose andother organic substances - Google Patents

Abstract

532,674. Cellulose derivatives ; resinous condensation products ; artificial silk &c. ; albumens. DREYFUS, H., MONCRIEFF, R. W., and BATES, H. July 18, 1939, Nos. 20826 and 27093. [Classes 2 (ii) and 2 (iii)] [Also in Group VIII] Filaments, fibres, foils, and other formed articles made of cellulosic or other organic substance containing hydroxy or -NH- groups are acidylated by heating them in a medium containing a mixed anhydride of a polycarboxylic acid and a lower monocarboxylic acid under such conditions that their form is retained. The mixed anhydride may be prepared from a polycarboxylic anhydride and a lower monocarboxylic acid or ester thereof, or from a lower monocarboxylic anhydride and a polycarboxylic acid or ester thereof, e.g. by heating a mixture of the reagents and removing free acid by distillation or by passing ketene through the mixture or by adding to it an organic base such as pyridine or an inorganic base such as calcium, barium, or strontium oxide. The use of a medium containing a mixed anhydride of a lower monocarboxylic acid and succinic, adipic, tartaric, or phthalic acid is excluded. Acetic, propionic, butyric, methoxy-, or ethoxy-acetic, or a chloracetic acid, may be used as monocarboxylic acid. Malonic, pimelic, sebacic, azelaic, iso- or terephthalic, maleic, malic, or citric acid may be used as polycarboxylic acid. The process is applicable to the treatment of yarns and other articles including those made 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 those made of cellulose derivatives such as cellulose acetate or other cellulose ester or ether. Acidylation may be affected 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 o-dichlorobenzene, may be used. In an example, a woven cellulose acetate fabric is heated in a medium prepared by heating sebacic acid with acetic anhydride, driving off the free acetic acid and dissolving the residue in xylene. The fabric is subsequently washed in carbon tetrachloride. 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 treatment they may be scoured and dry-cleaned to remove lubricant. The first Provisional Specification describes also the acidylation of cotton linters for the production of cellulose derivatives which can be dissolved in organic solvents and converted into filaments, foils, lacquers, or other products. The acidylation may be carried out in presence of a solvent for the cellulose derivative produced. Specification 532,673 is referred to.