Patent GB-378910-A (GB)
Title: Improvements in or relating to textile yarns and fabrics
Filed: 1931-05-15
Abstract: Crape effects are produced upon fabrics comprising highly twisted cr<\>zepe threads of cellulose acetate or other organic derivative of cellulose, by precipitating or forming a solid or semisolid substance within the highly twisted threads.  As suitable solid or semisolid substances there are mentioned the water-insoluble or substantially water-insoluble salts or hydroxides of calcium, barium, magnesium, aluminium, zinc, iron, copper, lead, or other heavy metal.  There may be used the insoluble salts of the above metals and inorganic or organic acids, e.g. sulphuric, carbonic, phosphoric, oxalic, tartaric, citric, mucic, saccharic, oleic, stearic, palmitic, ricinoleic, and lauric acids.  Difficultly soluble compounds such as metal compounds of casein or other albuminous materials are also mentioned.  The substance deposited in the fabric may contain substantial proportions of water; for example, a small quantity of citric acid yields a relatively large bulk of hydrated barium citrate when treated with barium hydroxide.  Moreover, substances having an appreciable solubility in water may be precipitated in the crape fabrics provided that precautions are taken to diminish the solubility of the substance, for example, by the addition of alkali metal salts or alcohol.  It is preferred to form the solid or semisolid substance within the crape threads in the finished fabrics, and moreover, it is advantageous to incorporate a suitable reagent in the threads before the application of a substantial portion of the twist and then to convert the said reagent into a solid or semisolid compound after the threads have been incorporated into fabrics.  The solid substances may, if desired, be subsequently removed from the fabrics by washing or other treatment.  The crape threads employed may be sized, preferably before the application of a substantial degree of twist, in which case they may be treated with a reagent adapted to convert the sizing material by chemical means into a material of greater bulk, e.g. a casein size saturated with citric acid may be employed, and the fabric subsequently treated with a solution of barium hydroxide whereby a swelling of the size is effected in addition to the formation of the barium citrate.  Again, the treatment to produce the solid or semisolid substance may be one which is adapted to cause a swelling of the material of the thread filaments.  The yarn may also, before or after crape twisting, be dehydrated with strong calcium chloride solution, woven into fabric and the latter treated with a reagent to precipitate an insoluble calcium salt.  The highly twisted crape threads may be incorporated in the fabrics in any suitable manner, e.g. these may be employed threads of low twist in the warp and crape threads of both right- and left-hand twist in the weft, pairs of threads of left-hand twist alternating with pairs of threads of right-hand twist.  Composite threads consisting of yarn of high twist doubled with yarn of low twist, or consisting of two yarns of high but opposite twist, may also be woven.  Where the fabrics comprise yarns of low twist, these yarns may be of similar material to the yarns of high twist, or may be composed of cotton or a regenerated cellulose type of artificial silk.  Specifications 332,903, [Class 120 (iii), Yarns &c.], 348,589, 352,000, 352,451, 356,233, 357,084, 357,169, and 357,576, 357,577, 358,585, [all in Group IX], 362,523, 365,040, 365,041, 375,355 are referred to.