Patent GB-674645-A (GB)
Title: Improvements in or relating to a process for reducing the shrinking tendencies of woven cotton fabrics
IPC: D06M15/423
Filed: 1950-01-17
Abstract: A colloidal aqueous solution of a polymerized, positively charged, aldehyde condensation product of an aminotriazine having at least two amino groups and a hydrogen atom attached to each amino nitrogen atom, contains 0.5-7 mols. of a water-soluble, saturated, aliphatic monocarboxylic or hydroxycarboxylic acid having a dissociation constant between 1.4 X 10-5 and 2.5 X 10-4 for each mol. of monomeric aminotriazine-aldehyde of which the polymerized product is composed, and is employed in a process for reducing the shrinking tendencies of woven cotton fabrics (see Group IV (c)).  The colloidal solution may be obtained by the process described in Specification 623,355.  The positively charged colloid particles migrate towards the cathode if the solution is submitted to electrophoresis.  In preparing the solution, it is necessary to allow ageing to take place for at least 3 hours.  If desired, the dispersion medium may be a mixture of water and a water-soluble polyhydric alcohol.  The solution may contain a softening agent for the cotton fabric, e.g. a reaction product of ethylene oxide with a mixture of the octadecylamine and octadecylguanidine salts of N-octadecyl carbamic acid.  Specified acids of the required dissociation constant are formic, acetic, propionic, butyric, isobutyric, gluconic, glycollic and lactic acids. In an example, 100 parts by weight of an 80 per cent aqueous methylated trimethylol melamine prepared as in example 2 of Specification 566,347 is mixed with 636.2 parts of water at 80-90 DEG F. and then 63.8 parts of glacial acetic acid is added.  The mixture is allowed to age for 12-16 hours at 70-90 DEG  F. before use. Instead of methylated trimethylol melamine, the unmethylated compound may be used.  In other examples, formic acid and glycollic acid are used instead of the glacial acetic acid.  Instead of melamine and its alkyl, aryl, or aralkyl derivatives, there may be used N-guanyl melamine, ammeline, formoguanamine, propioguanamine, and phenyl guanamine, and their derivatives.  Instead of formaldehyde, there may be used benzaldehyde, furfural, and acetaldehyde.  The condensation product is rendered water-insoluble after application to the fabric by heating at 65-400 DEG  F.  Specifications 623,362 and 655,541, [Group IV (c)], also are referred to.ALSO:A woven cotton fabric is rendered resistant to shrinking by impregnating it with a colloidal aqueous solution of a polymerized, positively-charged, aldehyde condensation product of an amino-triazine having at least two amino groups and a hydrogen atom attached to each amino nitrogen atom; this solution contains 0.5-7 mols. of a water-soluble, saturated, aliphatic monocarboxylic or hydroxycarboxylic acid with a dissociation constant between 1.4 X 10-5 and 2.5 X 10-4 for each mol. of monomeric amino-triazine-aldehyde of which the polymer is made; the take-up of the colloidal solution is such as to deposit in the fabric 2.5-15 per cent by weight, based on the dry weight of the fabric, of the polymer; and the impregnated fabric is dried so that the amino-triazine-aldehyde product deposited in the fabric is rendered water-insoluble.  The colloidal solutions may be obtained by the process of Specification 623,355, [Group IV (a)].  The positively charged colloid particles migrate towards the cathode when the solution is submitted to electrophoresis. The acid used may be formic, acetic, propionic, butyric, isobutyric, gluconic, glycollic, or lactic acid.  In preparing the positively-charged colloidal solution of the condensation product it is necessary to allow the solution to age for at least 3 hours.  If desired, a dispersion medium consisting of a mixture of water and a water-soluble polyhydric alcohol may be used.  In an example, cotton fabric is impregnated with a positively-charged colloidal solution of a polymerized trimethylol melamine containing acetic acid.  It is dried at 225 DEG  F. and then cured at 300 DEG  F.  It is then washed lightly with water containing N-octadecyl disodium sulphosuccinate and soda ash, then rinsed and dried.  The fabric may then be subjected to washing treatments with hot water containing sodium carbonate and soap.  It is found to be resistant to shrinking and to loss of tensile strength.  In other examples, the condensation product used is a polymerized methylated trimethylol melamine. Comparative tests are given which show that the treatment is not suitable for viscose rayon or viscose-cellulose acetate fabric, which suffer considerable loss in tensile strength.  The impregnating solution may contain a softening agent such as a reaction product of ethylene oxide with a mixture of the octadecylamine salt of N-octadecyl carbamic acid and the octadecylguanidine salt of N-octadecyl carbamic acid. Specifications 566,347, 623,362, [Group IV (a)], and 655,541 also are referred to.