Patent GB-179384-A (GB)
Title: Improvements in the dyeing of acetyl cellulose
IPC: D06P3/46
Filed: 1921-03-21
Abstract: Colloidal dye solutions are prepared by adding to a solution of dye or leuco-compound a protective colloid (gelatine, casein, saponin, starch, &c.) and a precipitant (except metallic chlorides). Suitable precipitants are:-For basic dyes, a weak alkali such as ammonia, a salt of an acid metallic oxide such as molybdates, tungstates, or stannates, or an organic compound of acid character such as tannic acid or salts of phenols, naphthols, aromatic acids, hydroxyacids, sulphonic acids, etc.; for acid or direct cotton dyes, a salt of an organic base such as aniline, benzidine, dianisidine, phenylenediamines, naphthylamines, &c. Sulphur dyes are dissolved in sodium sulphide, hydrosulphite, &c. and vat dyes in sodium hydrosulphite, the same precipitants being used as in the case of direct dyes. Examples are given of dye-baths containing:-Methylene blue, glue, and sodium stannate; magenta, saponin, and tannic acid; diamine sky blue, glue, dianisidine, and acetic acid; thional navy blue R, sodium sulphide, glue, dianisidine, and acetic acid; ciba blue 2B or indigo, caustic soda, sodium hydrosulphite, glue, dianisidine, and acetic acid. The Provisional Specification describes also the use of salts of aluminium, barium, magnesium, &c. as precipitants for direct or acid dyes, and of oxidizing agents such as air, or metal salts as precipitants for vat or sulphur dyes; it also refers to the use of alizarin dyes using metallic salts or mordants or organic bodies as precipitants.ALSO:Cellulose acetate goods are dyed with colloidal dye solutions prepared by adding to a solution of dye or leuco-compound a protective colloid (gelatine, casein, saponin, starch, &c.) and a precipitant (except metallic chlorides); preferably the precipitants are bodies which are themselves absorbed by the cellulose acetate. Suitable precipitants are :-for basic dyes, a weak alkali such as ammonia, a salt of an acid metallic oxide such as molybdates, tungstates, or stannates, or an organic compound of acid character such as tannic acids or salts of phenols, naphthols, aromatic acids, hydroxyacids, sulphonic acids, etc.; for acid or direct cotton dyes, a salt of an organic base such as aniline, benzidine, dianisidine, phenylene-diamines, naphylamines &c. Sulphur dyes are dissolved in sodium sulphate, hydrosulphite, &c. and vat dyes in sodium hydrosulphite, the same precipitants being used as in the case of direct dyes. Examples are given of dyeing triacetate silk in baths containing :-Methylene blue, glue, and sodium stannate; magenta, saponin, and tannic acid; diamine sky blue, glue, dianisidine, and acetic acid; thional navy blue R, sodium sulphide, glue, dianisidine, and acetic acid; ciba blue 2 B or indigo, caustic soda, sodium hydrosulphite, glue, dianisidine, and acetic acid.  Mixed goods containing cotton may be dyed with sulphur or vat dyes as described above, the cotton threads being subsequently dyed with direct dyes.  The Provisional Specification describes also the use of salts of aluminium, barium, magnesium, &c. as precipitants for direct or acid dyes, and of oxidizing agents such as air, or metal salts as precipitants for vat or sulphur dyes; it also refers to the use of alizarin dyes using metallic salts or mordants or organic bodies as precipitants.