Patent GB-734493-A (GB)
Title: Improvements in or relating to a process of improving synthetic polyamide fibre materials
IPC: D06M11/70
Filed: 1951-08-28
Abstract: Polyamide textile materials are treated in their entirety or locally with a 2 to 50 per cent solution by weight of an inorganic acid, a 5 to 40 per cent solution by weight of hydrogen peroxide or a 10 to 60 per cent solution by weight of a water-soluble organic aliphatic acid for 5 to 60 seconds at a temperature of not more than 100 DEG  C. in order to produce a superficial action on the material without appreciable injury to its mechanical properties. Specified treatment agents include lactic, oxalic, formic, acetic, hydrochloric, sulphuric, nitric and phosphoric acids.  The treated material can be dyed by cellulose-and wool-dyeing methods, and also by neutral dye bath liquors.  Spun yarns, staple fibre, woven and knitted fabrics and mixed fabrics containing polyamides may be treated.  By using fixed and unfixed yarns and/or polyamides of different chemical constitution, it is possible to obtain differential colour effects or shrinkage and creping effects. Local pattern effects may be obtained by printing insoluble resists inert to the treatment agent on the fabric.  The process may be carried out with or without tension in one or both directions of the fabric.  The action of the treatment agent may be stopped by washing out and, if necessary, neutralizing. The material may be permanently shaped or embossed before stopping the action.  In an example a caprolactam fibre fabric is treated without desizing in a solution containing 8 per cent hydrogen peroxide and 20 per cent acetic acid at 80 DEG  C. for 10 seconds. It is then cold-washed, neutralized and dyed with a direct dyestuff. Specifications 643,386 and 682,975 are referred to.ALSO:Polyamide textile materials are treated in their entirety or locally with a 2 to 50 per cent solution by weight of an inorganic acid, a 5 to 40 per cent solution by weight of hydrogen peroxide or a 10 to 60 per cent solution by weight of a water-soluble organic aliphatic acid for 5 to 60 seconds at a temperature of not more than 100 DEG  C. in order to produce a superficial action on the material without appreciable injury to its mechanical properties. Specified treatment agents include lactic, oxalic, formic, acetic, hydrochloric, sulphuric, nitric and phosphoric acids.  The treated material can be dyed by cellulose and wool-dyeing methods, and also by neutral dye-bath liquors.  Spun yarns, staple fibre, woven and knitted fabrics and mixed fabrics containing polyamides may be treated.  By using fixed and unfixed yarns, and/or polyamides of different chemical constitution, it is possible to obtain differential colour effects or shrinkage and creping effects. Local pattern effects may be obtained by printing insoluble resists inert to the treatment agent on the fabric.  The process may be carried out with or without tension in one or both directions of the fabric.  The action of the treatment agent may be stopped by washing out and, if necessary, neutralizing. The material may be permanently shaped or embossed before stopping the action.  In an example a caprolactam fibre fabric is treated without desizing in a solution containing 8 per cent hydrogen peroxide and 20 per cent acetic acid at 80 DEG  C. for 10 seconds. It is then cold-washed, neutralized and dyed with a direct dyestuff. Specifications 643,386 and 682,975, [Group IV (c)], are referred to.