Patent GB-1121753-A (GB)
Title: Production of polyester fibres with improved hydrophilic surfaces
IPC: D06M11/70
Filed: 1965-10-13
Abstract: A high melting, crystalline, linear, polyester fibre material is treated to give the material excellent wettability, good adhesive properties, a high resistance to soiling by oily soils and a hydrophilic surface by coating the fibre with an aqueous solution containing an inorganic acid that is non-volatile at 200 DEG C. and having a dissociation constant of at least 10-3, mixtures of such acids, ammonium salts of such acids, or volatile amine salts of such acids, to deposit on the surface from 0.05 to 5% by weight of such acid or salt, evaporating substantially all of the solvent, heating at 80 to 200 DEG C said substantially dry acid or salt-coated fibre, and washing said fibre to remove substantially all of said acid or salt.  Acids specified include phosphoric acid, phosphorous acid, perchloric acid, and sulphuric acid.  The material may be in the form of a fibre, cut staple, spun yarn, continuous filaments, filamentary tow or knitted or woven fabrics.  The polyester may be derived from a hexacarbocyclic nuclear dicarboxylic bifunctional compound wherein the carboxyl radicals are nuclearly substituted in the paraposition. Preferably the polyester is derived from a bifunctional glycol having from 2 to 10 carbon atoms.  Specified polyesters include polyethylene terephthalate, the polyester derived from pentamethylene glycol and 4, 4\sv-sulphonyl dibenzoic acid, the polyester derived from 1, 4-cyclohexanedimethanol and terephthalic acid, or a modified form of such a polyester.  A blend of a polyester fibre material and other natural or man-made fibre materials may be treated, for example a blend of 60% polyester fibres and 40% cotton fibres, or a blend of 50% polyester fibres and 50% of wool or regenerated cellulose fibres. The polyester may alternatively be derived from 4, 4\sv-diphenic acid, 1, 2-di(para-carboxyphenyl)-ethane, 1, 2-di(para-carboxyphenoxy)-ethane, 4, 4\sv-di-carboxydiphenyl ether and various esters of these acids such as the lower alkyl diesters. Such compounds are reacted in known manner with bifunctional glycols containing from about 2 to about 10 carbon atoms, e.g. ethylene glycol, tetramethylene glycol, 2, 2, 4, 4-tetraalkyl-1, 3-cyclobutanediol, pentamethylene glycol, neopentylene glycol, 1, 4-cyclohexane-dimethanol, quinitol and 1, 4-bis(hydroxy ethyl) benzene.  In a preferred method, there is deposited 0.3 to 1.0%, of the treating agent based on the weight p  of polyester material, and the treated material is heated to 100 to 160 DEG C.  The treating agent may be applied in aqueous or aqueous-organic solvent solution and a surfactant may be present in the solution of the treating agent.  Examples describe (1) the treatment of polyethylene terephthalate fibres with phosphoric acid in aqueous solution; (2) the treatment of a fabric of polyethylene terephthalate with phosphorous acid, similar results being obtained in the treatment of fabrics made from poly(1, 4-cyclohexane dimethylene terephthalate), poly (ethylene 2,6-naphthalenedicarboxylate) and poly (pentamethylene 4, 4-sulphonyldibenzolate).  In Example 3 the method of Example 2 is applied, using phosphoric acid.  In Example 4 a mixture of phosphoric acid and sulphuric acid is applied by the method of Example 2.  In Example 5 a polyethylene terephthalate fabric is treated with sulphuric acid.  In Example 6 a tow of polyethylene terephthalate fibres is treated with phosphoric acid, dissolved in butyl alcohol or isopropyl alcohol and water, and containing a non-ionic wetting agent.  In Example 7, fibres of polyethylene terephthalate are treated with perchloric acid, or with the pyridine, ethylamine or trimethylamine salt of perchloric acid. In Example 8, a fabric made from polyethylene terephthalate is treated with a water solution of the monopyridene salt of sulphuric acid.