GB905833A - Improvements in the treatment of filaments, films and other shaped articles of synthetic polymers - Google Patents

Abstract

Filaments, films &c., having an oriented structure, consisting of a polyester, a polyamide, a polyimide, a polyurea, a polyurethane or a polyhydrocarbon, and being of uniform cross-section except for the presence of randomly distributed short-length regions, transverse to the axis of orientation, which are of smaller cross-section, and which occur with a frequency of at least 10 per inch, and preferably 500 to 20,000 per inch, and have distributed therein a "modifier", such as a dye or other colouring material, are produced by drawing unoriented or incompletely oriented filaments &c. while they are in contact with a "surface-crack-promoting agent" which either is or contains a modifier, the conditions of drawing being such that the desired oriented structure is obtained. The "SCPA" should not be a solvent or strong swelling agent for the polymer, and should preferably be a liquid, but may be a gas. The agent preferably has a surface tension measured relative to air not greater than 60 dynes per cm. at the treating temperature and is preferably non-aqueous, water itself being unsatisfactory. The cracking solution preferably contains at least 10%, and more especially 25% by weight of a non-aqueous organic liquid. The agent preferably has a wetting angle of less than 90 degrees and especially as low as 30 degrees. The modifier is preferably soluble in the agent. The modifier may be a lubricant such as a silicone oil, 2-ethoxy acrylate or ethyl acrylate. It may be a flame-proofing or retarding agent, such as bis(chloroethyl) vinyl phosphate or phylic acid. The modifier or additive may be an inorganic salt such as silver nitrate or potassium dichromate, a colloid such as colloidal carbon black, a wetting agent or hydrophobic agent, an anti-soil or anti-static additive, an adhesive or bonding agent, especially for rubber, a mixture of different dyes of different or the same type, or of a dyestuff, an anti-static additive and an ultra-violet light absorber. A reactive modifier may be introduced into the filaments &c. and subsequently or simultaneously reacted with another material, e.g. a dye mordant or dye assistant may first be introduced into the filaments which are subsequently treated with a dye. Numerous other types of modifiers are specified and examples are given of the treatment according to the invention of undrawn filaments of polyethylene terephthalate, nylon 66, poly(m-phenylene isophthalamide), polypropylene and a polyurethane derived from ethylene bischloroformate and piperazine. The "cracking agents" used in the examples include purified kerosine, ethanol containing a dye, mixtures of ethanol and water containing a dye, a 5% ethanol solution of acrylic acid, mixtures of acetone and water and mixtures of acetic acid and water. A description is given of a simple test for determining whether a given liquid is a suitable "cracking agent" for filaments of a specific polymer. The drawing of the filaments is preferably carried out below 30 DEG C. The process renders it possible to cause dyes to penetrate very deeply into filaments even when there is no chemical affinity between the dye and the filament polymer. A mixture of an addition polymer and a compatible monomer of low molecular weight may be used in the spinning process and during the drawing process of the invention the monomer can be activated for further addition polymerization by imbibing a catalyst into the polymeric filament or film. Grafted copolymer filaments &c. may be obtained by infusing the filaments &c. with a graftable additive during drawing and the latter then caused to graft on the polymer chain by thermal, chemical or other initiation. Specification 608,332, Belgium Specification 546,815 and U.S.A. Specification 2,278,888 are referred to.ALSO:Filaments, films &c., having an oriented structure, consisting of a polyester, a polyamide, a polyimide, a polyurea, a polyurethane or a polyhydrocarbon, and being of uniform cross-section except for the presence of randomly distributed short-length regions, transverse to the axis of orientation, which are of smaller cross-section, and which occur with a frequency of at least 10 per inch, and preferably 500 to 20,000 per inch, and have distributed therein a "modifier", such as a dye or other colouring material, are produced by drawing unoriented or incompletely oriented filaments &c. while they are in contact with a "surface-crack-promoting agent" which either is or contains a modifier, the conditions of drawing being such that the desired oriented structure is obtained. The "SCPA" should not be a solvent or strong swelling agent for the polymer, and should preferably be a liquid, but may be a gas. The agent preferably has a surface tension measured relative to air not greater than 60 dynes per cm. at the treating temperature and is preferably non-aqueous, water itself being unsatisfactory. The cracking solution preferably contains at least 10%, and more especially 25% by weight of a non-aqueous organic liquid. The agent preferably has a wetting angle of less than 90 degrees and especially as low as 30 degrees. The modifier is preferably soluble in the agent. The modifier may be a lubricant such as a silicone oil, 2-ethoxy acrylate or ethyl acrylate. It may be a flame-proofing or retarding agent, such as bis(chloroethyl) vinyl phosphate or phylic acid. The modifier or additive may be an inorganic salt such as silver nitrate or potassium dichromate, a colloid such as colloidal carbon black, a wetting agent or hydrophobic agent, an anti-soil or anti-static additive, an adhesive or bonding agent, especially for rubber, a mixture of different dyes of different or the same type, or of a dyestuff, an anti-static additive and an ultraviolet light absorber. A reactive modifier may be introduced into the filaments &c. and subsequently or simultaneously reacted with another material, e.g. a dye mordant or dye assistant may first be introduced into the filaments which are subsequently treated with a dye. Numerous other types of modifiers are specified and examples are given of the treatment according to the invention of undrawn filaments of polyethylene terephthalate, nylon 66, poly (m-phenylene isophthalamide), polypropylene and a polyurethane derived from ethylene bischloroformate and piperazine. The "cracking agents" used in the examples include purified kerosine, ethanol containing dye, mixtures of ethanol and water containing a dye, a 5% ethanol solution of acrylic acid, mixtures of acetone and water and mixtures of acetic acid and water. A description is given of a simple test for determining whether a given liquid is a suitable "cracking agent" for filaments of a specific polymer. The drawing of the filaments is preferably carried out below 30 DEG C. The process renders it possible to cause dyes to penetrate very deeply into filaments even when there is no chemical affinity p between the dye and the filament polymer. Specification 608,332, Belgian Specification 546,815 and U.S.A. Specification 2,278,888 are referred to.