Patent GB-407000-A (GB)
Title: Improvements in the manufacture of artificial filaments, threads, and ribbons
IPC: D01F2/28
Filed: 1932-07-04
Abstract: Inorganic pigments, are subjected to or prepared from intermediate substances by heating between 200 DEG  and 500 DEG  C. under reduced pressure.  This treatment may remove water or dehydrate the material, as in the dehydration of a hydrated salt or the production of an oxide from a hydroxide.  Pigments include barium, calcium and lead sulphates and carbonates, titanium dioxide, zinc oxide, alumina, stannic oxide, stannic phosphate, antimony trioxide, barium phosphate, zinc and magnesium carbonates, barium and calcium borates, barium and lead chromates, cadmium sulphide, Prussian blue, cobalt yellow, chrome yellow, iron red, chrome red, blue verditer, Schnitzer's green, manganese brown, vandyke brown, and phosphorescent materials such as zinc sulphide as in Specification 340,636, [Group IV].  The pigments may be thus heated in the presence of suitable organic compounds which may be liquid or vapour under the conditions of heating and which may be plasticizing agents.  These include heavy oils such as heavy white mineral oil or olive, castor or other vegetable oil and substances such as in Specification 403,944, [Group IV], ethylene and trimethylene glycols, aromatic and alicyclic alcohols such as benzyl alcohol, cyclohexanol, and esters of polyhydroxy alcohols such as di- and triacetin, or mixtures thereof. The pressures may be of the order of 500 to 400 mms., down to substantially a total vacuum.  The apparatus employed may be a closed vessel fitted with stirring apparatus, a vacuum oven, a long tube with a screw conveyer or endless band and may be used in conjunction with a dehydrating or absorbing agent such as calcium chloride or activated charcoal.  A current of dry air or other gas may traverse the chamber and the materials and the heating means which may be oil bath, molten metal bath, direct or by means of steam pipes, may be arranged to subject the material to a temperature gradient during its treatment.  The material may be further ground before incorporation in the textile or spun products to a size preferably below 0.006 mm. In examples: (1) precipitated aluminium hydroxide is heated at 200 DEG  under 10 to 20 cms. pressure for 1 to 2 hours while a small current of dry air passes through the chamber.  It is then ground to a particle size of 1 to 2 microns and incorporated in a 25 per cent solution of cellulose acetate in acetone in a concentration of 2 to 3 per cent of the cellulose acetate; (2) precipitated titanic acid is heated at 300 DEG  to 400 DEG  C. under 10 to 20 cms. pressure while travelling through a tube.  It is then treated similarly to the material of (1).  The Provisional Specification describes also the drying of colloidal or finely divided metals and is not limited to any specific temperature range.ALSO:Artificial filaments, threads and ribbons, produced by wet or dry spinning processes have incorporated in them inorganic pigments which have been subjected to or prepared from intermediate substances by heating between 200 DEG  and 500 DEG C. under reduced pressure.  This treatment may remove water or dehydrate the material, as in the dehydration of a hydrated salt or the production of an oxide from a hydroxide.  Pigments include barium, calcium and lead sulphates and carbonates, titanium dioxide, zinc oxide, alumina, stannic oxide, stannic phosphate, antimony trioxide, barium phosphate, zinc and magnesium carbonates, barium and calcium borates, barium and lead chromates, cadmium sulphide, Prussian blue, cobalt yellow, chrome yellow, iron red, chrome red, blue verditer, Schnitzer's green, manganese brown, vandyke brown, and phosphorescent materials such as zinc sulphide as in Specification 340,636.  The pigments may be thus heated in the presence of suitable organic compounds which may be liquid or vapour under the conditions of heating and which may be plasticizing agents.  These include heavy oil such as heavy white mineral oil or olive castor or other vegetable oil and substances such as in Specification 403,944, ethylene and trimethylene glycols, aromatic and alicyclic alcohols such as benzyl alcohol, cyclohexanol, and esters of polyhydroxy alcohols such as di- and triacetin, or mixtures thereof.  The pressures may be of the order of 500 to 400 mms., down to substantially a total vacuum.  The apparatus employed may be a closed vessel fitted with stirring apparatus, a vacuum oven, a long tube with a screw conveyer or endless band and may be used in conjunction with a dehydrating or absorbing agent such as calcium chloride or activated charcoal.  A current of dry air or other gas may traverse the chamber and the materials and the heating means which may be oil bath, molten metal bath, direct or by means of steam pipes, may be arranged to subject the material to a temperature gradient during its treatment.  The material may be further ground before incorporation in the textile or spun products to a size preferably below 0.006 mm. The materials may be incorporated either into the spinning solutions to produce coloured or delustred products or into the formed products, which may be swollen, by passing them into a dispersion of the pigments.  The pigments may be incorporated into cellulose esters, mixed esters, ethers, mixed ethers, mixed ether-esters, and regenerated cellulose.  In examples: (1) precipitated aluminium hydroxide is heated at 200 DEG  C. under 10 to 20 cms. pressure for 1 to 2 hours while a small current of dry air passes through the chamber.  It is then ground to a particle size of 1 to 2 microns and incorporated in a 25 per cent solution of cellulose acetate in acetone in a concentration of 2 to 3 per cent of the cellulose acetate; (2) precipitated titanic acid is heated at 300 DEG  to 400 DEG  C. under 10 to 20 cms. pressure while travelling through a tube. It is then treated similarly to the material of (1).  Filaments or threads treated in this manner have a reduced tendency to cut the guides and knitting needles during subsequent textile operations. The Provisional Specification describes also the drying of colloidal or finely divided metals and is not limited to any specific temperature range.