Patent GB-758745-A (GB)
Title: Process for improving properties of fibres, films or sheets made of synthetic thermoplastic material
IPC: D06M11/38
Filed: 1954-01-06
Abstract: The affinity for dyes of fibres, films or sheets made from polyamides, polyesters, polyacrylonitrile or copolymerization products of acrylonitrile with not more than an equal proportion of other vinyl or acrylic compounds, is improved by subjecting the fibres or other materials in a substantially non-aqueous medium to the action of a strong base and then removing the base from the treated materials, the duration of treatment, temperature and concentration of the base being adjusted so that a superficial action only on the fibre, film or sheet is produced.  Polymerized hexamethylene adipamide or glycol terephthalate materials may be treated.  The bases may be applied at elevated temperature in the form of solutions in solvents containing no water or only minor amounts of water, or in the form of non-aqueous dispersions or emulsions.  If desired they may be applied at ordinary temperature over the whole area of the material or locally, and heat may be applied subsequently by treatment in hot non-aqueous media, the heat being transmitted by solid, liquid, or gaseous bodies or by radiation.  The strong base may be a hydroxide of sodium, potassium, calcium, barium or magnesium or it may be an organic nitrogen base such as a quaternary ammonium hydroxide.  As solvent for the base there may be used ethylene glycol, glycerol or triethanolamine or its homologues or polymers.  Pattern effects may be obtained by applying resists to the material, treating it with the strong base and then dyeing.  The duration of the treatment with the strong base should be not more than 10 minutes and should preferably be less than 5 minutes at temperatures above 100 DEG  C.  Auxiliary agents such as wetting, swelling, oxidizing and reducing agents may be incorporated in the strong base preparation.  Dyes, pigments, softening agents and other finishing agents may also be present.  The treated material may be subjected to other treatments such as those involving the use of acids, cross-linking agents, oxidizing agents and reducing agents. If the materials are discoloured by the treatment with the strong base, the colour may be restored by treatment with acids or bleaching agents, e.g. hydrogen peroxide.  Pattern effects may be obtained by dyeing materials containing both treated and untreated fibres or fibres of a different kind.  The treatment also improves the feel or handle, particularly in the case of polyacrylonitrile fibres; it subdues the lustre and increases the absorbency of the materials.  If carried out without tension the treatment causes shrinkage, and crepe or crimp effects may be obtained by local treatment or by treatment of materials containing fibres of different kinds.  In examples, fabrics, yarns and staple fibres of polyacrylonitrile or acrylonitrilevinyl chloride copolymer or nylon are treated with 8-10 per cent solutions of caustic soda, barium hydroxide or tetra-ethyl ammonium hydroxide in ethylene glycol for 2 minutes at 120-150 DEG C. and are then dyed with dyestuffs of various kinds.  In one example a fabric is treated locally by screen-printing with a paste containing caustic potash, water, glycerol and tragacanth-starch thickener, drying at 60 DEG  C. and then heating in a paraffin oil bath.  After removing the paraffin, the treated fabric is dyed with an acid dyestuff, Cloth Fast Brilliant Red 4 BN.ALSO:The affinity for dyes of fibres, films or sheets made from polyacrylonitrile or copolymers of acrylonitrile with not more than an equal proportion of other vinyl or acrylic compounds, or from polyamides or polyesters, is improved by subjecting the fibres or other materials in a substantially non-aqueous medium to the action of a strong base and then removing the base from the treated materials, the duration of treatment, temperature and concentration of the base being adjusted so that a superficial action only on the fibre, film or sheet is produced.  Polymerized hexamethylene adip amide or glycol terephthalate materials may be treated.  The duration of the treatment should not be more than 10 minutes and preferably less than 5 minutes at temperatures above 100 DEG C.  If desired, the base may be applied at ordinary temperature over the whole area of the material or locally, and heat may be applied subsequently by treatment in hot non-aqueous media, the heat being transmitted by solid, liquid, or gaseous bodies or by radiation.  The base may be a hydroxide of sodium, potassium, calcium, barium, or magnesium, or it may be an organic base such as a quaternary ammonium hydroxide.  As solvent for the base there may be used ethylene glycol, glycerol or triethanolamine or its homologues or polymers.  Pattern effects may be obtained by applying resists to the material, then treating with the strong base, and subsequently dyeing.  Wetting, swelling, oxidizing, reducing or other agents may be incorporated in the strong base preparation.  Dyes, pigments and softening agents may also be present.  If the materials are discoloured by the treatment with the base, the colour may be restored by subsequent treatment with acids or bleaching agents, e.g. hydrogen peroxide.  Pattern effects may be obtained by dyeing materials containing both treated and untreated fibres or fibres of a different kind.  In examples, fabrics, yarns and staple fibres of polyacrylonitrile or of acryllonitrile-vinyl chloride copolymer or of nylon are treated with an 8-10 per cent solution of caustic soda, barium hydroxide or tetra-ethyl ammonium hydroxide in ethylene glycol for 2 minutes at 120-150 DEG C.  The materials are washed and then dyed with a solution of Chlorantine Fast Brown BRLL; or with an acetate dyestuff.  Artisil Direct Blue SAP; or with a solution containing Brilliant Indocarbon CLS, sodium sulphide and caustic soda and subsequently developing the dyestuff by hydrogen peroxide treatment; or with a solution of a vat dyestuff, Cibanon Brilliant Green 4G, caustic soda, sodium hydrosulphite and sodium nitrite, and subsequent development with hydrogen peroxide; or with a solution of an acid dye, Cloth Fast Brilliant Red 4BN; or with a solution of Naphthol AS followed by development with Fast Red Salt 3GL.  In another example, a pretreated fabric is dye-printed with a paste comprising a vat dyestuff Cibanon Brillian Green 4G, tragacanth, sodium hydrosulphite, potassium carbonate, anthraquinone and water, with subsequent steaming and treatment with peroxide.  In another example, after pretreating with caustic soda in glycol and dyeing with an acid dyestuff.  Cloth Fast Brilliant Red, a polyacrylonitrile fabric is screen-painted with a discharge paste containing caustic soda, formaldehyde sulphoxylate, anthraquinone and water, and is then steamed, acidified and washed.  In another example, a polyacrylonitrile fabric is treated locally by screen-printing with a paste containing caustic potash, water, glycerol, and tragacanth-starch thickener, drying at 60 DEG C., and then heating in a paraffin oil bath.  After removing the paraffin, the fabric is dyed with an acid dyestuff, Cloth Fast Brilliant Red 4 BN.