Patent GB-1214964-A (GB)
Title: Improvements in processes for the heat treatment of textile filamentary structures with hot gases
Inventor: FERNANDES HAROLD
IPC: D02J13/00
Filed: 1969-02-20
Abstract: 1,214,964. Heat treating synthetic yarns with hot gases. E. I. DU PONT DE NEMOURS & CO. 20 Feb., 1969 [20 Feb., 1968; 18 Sept., 1968], No. 9332/69. Heading B5B. [Also in Division B1] In processes in which textile filamentary structures such as synthetic yarns having a coating of a textile finish containing oxidizable organic components which are vaporizable at the treating temperature are treated with a hot gas at a temperature within the range of about 100‹ C. to about 250‹ C., whereby a portion of the organic components of said finish are vaporized to produce an undesirable vapour and transported by the hot gas, at least a portion of the hot gas leaving the treating zone and containing said vapour is directed through a gas-permeable solid medium or structures having a catalyst for oxidation of the oxidizable organic components of the textile finish in a finely dispersed form on the solid medium or structure to oxidize said vaporized organic components to a state in which they are not undesirable or are less undesirable. The gas may be continuously recirculated through the heat treating zone. The gas-permeable medium may be comprised of activated alumina granules. The gas permeable structure may be comprised of a ceramic honeycomb coated with activated alumina. The oxidation catalyst may be palladium or platinum or mixtures thereof. In an example, an aqueous solution of manganese nitrate, nickel nitrate, cobalt nitrate, and chromium trioxide is prepared, and mixed with an aqueous solution of ammonium carbonate, the resulting precipitate is filtered, washed with water, mixed with activated carbon, aluminium hydrate and colloidal silica, and the mixture is milled dried at 150‹ C. and calcined at 350‹ C. for 30 minutes. The resulting catalyst is crushed, screened to 6 to 10 mesh, the granules moistened with palladium nitrate solution, the moist granules dried and calcined for 30 minutes at 250‹ C., moistened with a chloro platinic acid solution and again dried and calcined at 250‹ C. for 30 minutes. In the process of the invention the continuous catalytic oxidation of the volatilized portion of the finish in the hot gas exhausted from the zone in which the running coated yarn is heat treated prevents the accumulation and the decomposition of the volatilized finish in the recirculated gas with formation of objectionable deposits in the treatment system. The textile material treated in the examples is a continuous filament polyamide yarn and the heat treatment temperatures used in the examples are 130‹ C., 180‹ C. and 190‹ C. respectively. The oxidizable textile finish used for coating the yarns may, for example, be a solution containing 98% of the di-(2-ethyl-hexanoate) of a mixture of polyethylene glycols having an average molecular weight of about 238, and 2% of 4,4<SP>1</SP>-thio-bis-(3-methyl-6-tert.-butyl phenol, or may, for example, be a solution containing 54 parts by weight of butyl stearate, 15 parts by weight of sorbitan monolaurate and 31 parts by weight of a refined kerosene.