Patent GB-343124-A (GB)
Title: Improvements in the colouration of materials made of or containing cellulose derivatives
IPC: D06P3/40
Filed: 1929-11-08
Abstract: Aqueous dispersions of metal oxides for use in mordanting materials made of or containing cellulose esters or ethers are obtained as follows: (1) A dispersion of titanium oxide is obtained by adding a 5 per cent caustic soda solution to a solution of titanium sulphate of a strength corresponding to 5 per cent of TiO2 while maintaining the temperature at 0-5 DEG  C., separating, washing, draining, and pressing the precipitated hydroxide to a paste containing about 20 per cent of TiO2, stirring into this paste concentrated hydrochloric acid corresponding to 1-2 per cent of HCl calculated on the weight of TiO2, heating to 80-100 DEG  C. until it gelatinizes, a further quantity of the acid being added, if desired, to facilitate dispersion, and diluting with water to give a sol containing about 5 per cent of TiO2; (2) A dispersion of alumina is obtained similarly, using aluminium sulphate instead of titanium sulphate; (3) A dispersion of alumina is obtained by adding aqueous ammonia to a solution of alum, filtering and washing the precipitate, boiling it with about 200 times its weight of water, and adding \baN/20\be hydrochloric acid in quantity corresponding to about \ba1/10\be of the weight of the liquor.  Other mordants specified are the oxides of zinc, chromium, iron, cerium, and tin.ALSO:Mordant dyes, dyeing with; cellulose esters or ethers, dyeing; regenerated celluloses, dyeing; printing.-In the mordant dyeing of materials made of or containing cellulose esters or ethers the mordant metals are applied in the form of suspensions, dispersions, or colloidal solutions of the mordant metal oxides or compounds.  The invention is applicable to mixed materials containing cellulose esters or ethers in admixture with other fibres such as silk, cotton, regenerated cellulose, or wool. The mordant metal oxides or compounds may be applied by any of the processes described in Specification 343,121, and the dyes may be applied before or after the mordanting.  For local colouration either local application of the mordant and uniform application of the dyestuff or local application of the dyestuff and uniform application of the mordant may be adopted.  Specified mordant metals are titanium, zinc, aluminium, chromium, iron, cerium, or tin, and specified dyestuffs are h matein, fustic, Persian berries, alizarin and other mordant dyes of the anthraquinone series, gallocyanines, and o-oxyazo dyestuffs.  The following examples are specified.  (1) Cellulose acetate yarn or fabric is dyed by treatment for 1 hour at 70-75 DEG  C. in a bath containing H matein, Anthracene blue WG new, Gallocyanine, Alizarin orange, or Alizarin yellow after mordanting by treatment for 10-30 minutes at 60 DEG  C. in a bath containing a dispersion of titanium oxide; a suitable dispersion is obtained by adding a 5 per cent caustic soda solution to a solution of titanium sulphate of a strength corresponding to 5 per cent of TiO2 while maintaining the temperature at 0-5 DEG  C., separating, washing, draining, and pressing the precipitated hydroxide to a paste containing about 20 per cent of TiO2, stirring into this paste concentrated hydrochloric acid corresponding to 1-2 per cent HCl calculated on the weight of TiO2, heating to 80-100 DEG  C. until it gelatinizes, a further quantity of the acid being added, if desired, to facilitate dispersion, and diluting with water to give a sol containing about 5 per cent of TiO2.  (2) The goods are dyed by treatment for 1 hour at 70-75 DEG  C. in a bath containing alizarin and calcium acetate after mordanting by treatment at 50-70 DEG  C. in a bath containing a dispersion of 4-8 per cent of alumina until the required absorption is obtained; a suitable dispersion is obtained as described in (1) using aluminium sulphate instead of titanium sulphate.  (3) A cellulose acetate yarn or fabric is dyed by treatment for 1 hour at 50-70 DEG  C. in a bath containing Acid green after mordanting by treatment for 20-30 minutes in a bath containing a dispersion of alumina; a suitable dispersion is obtained by adding aqueous ammonia to a solution of alum, filtering and washing the precipitate, boiling it with about 200 times its weight of water, and adding N/20 hydrochloric acid in quantity corresponding to about 1/10 of the weight of the liquor.