Patent GB-688135-A (GB)
Title: Stabilization against shrinkage of textile fabrics consisting predominantly of regenerated cellulose
IPC: D06M15/39
Filed: 1950-03-24
Abstract: Textile fabrics consisting predominantly of regenerated cellulose are stabilized against shrinkage under repeated washings by impregnation with an aqueous alkaline liquid containing a water-insoluble alkali-soluble cellulose ether having free hydroxyl groups and a saturated aliphatic aldehyde or a water-soluble, liquid, potentially thermosetting condensation product of such an aldehyde with a saturated aliphatic ketone, removal of excess treating liquid and heating.  The term "water-insoluble alkali-soluble cellulose ether" covers those ethers soluble in 2-8 per cent aqueous alkali and includes alkyl ethers, carboxyalkyl ethers, mixed alkyl hydroxyalkyl ethers, mixed alkyl carboxyalkyl ethers and the salts of the carboxyalkyl ethers which contain free hydroxyl groups.  The impregnating liquid may contain 0.5-2 per cent by weight of the cellulose ether, 5-40 per cent, preferably 10 per cent, by weight of the aldehyde or condensate, and may have a pH of 12.2-13.0.  The thermosetting condensate may be obtained by reacting an aliphatic aldehyde and an aliphatic ketone in the presence of a catalyst such as sodium or potassium hydroxide, dipotassium hydrogen phosphate, trisodium phosphate or borax.  On completion of the reaction, the catalyst may be neutralized with acid (in the case of caustic alkalis) or removed by addition of barium or calcium chloride. Suitable aldehydes include formaldehyde, acetaldehyde, propionaldehyde and butyraldehyde; suitable ketones include acetone, diethyl ketone, methyl ethyl ketone and methyl propyl ketone.  The cellulose ether and the aldehyde or aldehyde-ketone condensate are preferably dissolved in the aqueous alkali.  In an example, a regenerated cellulose staple fibre fabric is passed into an aqueous alkaline solution containing 1 pound of water-insoluble hydroxyethyl cellulose soluble in 3 per cent aqueous sodium hydroxide at 20 DEG C., 10 pounds of 37 per cent formaldehyde and 1 pound of dry caustic soda per 100 pounds of solution.  It is squeezed, passed through 3.8 per cent sulphuric acid to coagulate the ether, washed, scoured and heated at 260 DEG  F. in relaxed condition.  In an example of the preparation of the aldehyde-ketone condensate, 15 parts of formaldehyde (as trioxymethylene) are mixed with 15 parts of acetone dissolved in 15 parts of water.  About one part of trisodium phosphate dissolved in a small quantity of water is added and the mixture is allowed to reflux, external heating being stopped when the reaction begins.  When the reaction stops, the mixture is heated to boiling for a short time and cooled for 12 hours at room temperature. Aqueous barium chloride is added to precipitate the phosphate, the pH being maintained at 7.  The barium phosphate is filtered and volatile substances removed by heat to form a thick viscous liquid.  Any precipitated salt is filtered off.ALSO:Textile fabrics consisting predominantly of regenerated cellulose are stabilized against shrinkage under repeated washings by impregnation with an aqueous alkaline liquid containing a water-insoluble alkali-soluble cellulose ether having free hydroxyl groups and a saturated aliphatic aldehyde or a water-soluble, liquid, potentially thermosetting condensation product of such an aldehyde with a saturated aliphatic ketone, removal of excess treating liquid, and heating.  The term "water-insoluble alkali-soluble cellulose ether" covers those ethers soluble in 2-8 per cent aqueous alkali and includes alkyl ethers, carboxyalkyl ethers, mixed alkyl hydroxyalkyl ethers, mixed alkyl carboxyalkyl ethers and the salts of the carboxyalkyl ethers which contain free hydroxyl groups.  The cellulose ether may be coagulated on the fabric prior to heating by passage of the fabric through aqueous acid, or it may be coagulated simultaneously with the curing of the condensation product at about 280 DEG  F.  After the heating the fabric is rinsed and then dried.  The impregnating liquid may contain 0.5-2 per cent by weight of the cellulose ether, 5-40 per cent, preferably 10 per cent, by weight of the aldehyde or condensate, and may have a pH of 12.2-13.0.  The thermosetting condensate may be obtained by reacting an aliphatic aldehyde and an aliphatic ketone in the presence of a catalyst such as sodium or potassium hydroxide, dipotassium hydrogen phosphate trisodium phosphate or borax (see Group IV (a)).  Suitable aldehydes include formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde; suitable ketones include acetone, diethyl ketone, methyl ethyl ketone and methyl propyl ketone.  The cellulose ether and the aldehyde or aldehydeketone condensate are preferably dissolved in the aqueous alkali at room temperature and the solution applied to the textile fabric at room temperature by spraying, dipping or otherwise impregnating.  Any excess may be removed by centrifuging or squeezing.  In an example a plain weave 100 per cent regenerated cellulose staple fibre fabric is passed into an aqueous alkaline solution containing 1 lb. of water-insoluble hydroxyethyl cellulose soluble in 3 per cent aqueous sodium hydroxide at 20 DEG  C., 10 pounds of 37 per cent formaldehyde and 1 pound of dry caustic soda per 100 lbs of solution.  It is squeezed to 70 per cent pick-up, passed through 3.8 per cent sulphuric acid to coagulate the ether, washed, scoured and heated at 260 DEG  F. for 5 minutes in relaxed condition.