Patent GB-369344-A (GB)
Title: An improved process for bleaching and dyeing furs, hairs, skins and leather
IPC: D06L4/10
Filed: 1931-02-17
Abstract: Any solid adsorbent such as silica gel, infusorial earth or silica, a calcined inorganic salt such as sodium pyrophosphate, sawdust or wood meal in a pulverent condition is impregnated with such an amount of an alkaline hydrogen peroxide solution that the mass is just dry. All adsorbents may be treated with a stabilizer for hydrogen peroxide and infusorial earth, which has an accelerative effect on bleaching, may be used in admixture with other adsorbents.  In examples the following bleaching agents are described : (1) a hydrogen peroxide solution containing ammonia, sodium phosphate, and turkey-red oil adsorbed in silica gel; (2) sawdust impregnated with a solution of hydrogen peroxide and ammonia; (3) hardwood sawdust impregnated with hydrogen peroxide; (7) sawdust impregnated with hydrogen peroxide and monopol soap; (8) granulated sodium pyrophosphate or a mixture thereof with sawdust or wood meal impregnated with hydrogen peroxide.ALSO:Furs, hairs, skins, or leather, such as kid-leather or chamois leather, are bleached or dyed with solid adsorbents charged with the liquids serving for the bleaching or dyeing.  For bleaching, for example, furs, by means of an alkaline hydrogen peroxide solution any inert adsorbent such as silica gel, infusorial earth or silica, or a calcined inorganic salt such as sodium pyrophosphate in a pulverent condition is impregnated with such an amount of the solution that the mass will still feel dry.  Sawdust or wood meal is the prepared adsorbent and all adsorbents may be pretreated with a stabilizer for hydrogen peroxide and may be used repeatedly. Infusorial earth has an accelerative effect on bleaching and may be used in admixture with other adsorbents. Besides hydrogen peroxide other liquids evolving oxygen or other known bleaching agents such as those containing or evolving chlorine or sulphur dioxide may be used whilst the adsorbents may also be impregnated with dyestuffs or developers for dyestuffs where the goods have been pretreated with a developable dyestuff. The grain size of the adsorbent varies the effects produced and the goods, which may be embedded in the changed adsorbent or agitated or sprinkled therewith, may be treated only in parts to produce spots or stripes.  In examples (1) a hydrogen peroxide solution containing ammonia, sodium phosphate and turkey-red oil is adsorbed in silica gel and fur are bleached therewith by agitation in a drum.  (2) Dry human hair is bleached by being sprinkled with sawdust impregnated with a solution of hydrogen peroxide and ammonia.  (3) Skins which have to be cleared at the surface only are laid face downwards in hardwood sawdust which has been impregnated with hydrogen peroxide.  (4) Genuine skins are embellished by treatment with sawdust impregnated with a solution of ursol containing hydrogen peroxide or by separate treatment with the adsorbed dyestuff alone and adsorbed hydrogen peroxide.  By rubbing or treating single spots local effects may be obtained.  (5) For ameliorating skins a solution of ursol D.F. may be sprinkled on the skins and then treated with sawdust impregnated with hydrogen peroxide.  (6) For drawing the darker stripe on the back line of skins they are first treated with sawdust containing hydrogen peroxide and ammonia, the stripes are then drawn on with the dyeing solution and the stripe is then rubbed with sawdust containing hydrogen peroxide and glycerine. (7) Chamois leather is shaken with sawdust impregnated with hydrogen peroxide and monopol soap.  (8) Skins are bleached with granulated sodium pyrophosphate or a mixture thereof with sawdust or wood meal impregnated with hydrogen peroxide.