Patent GB-441573-A (GB)
Title: Improvements in the manufacture of crepe threads and fabrics
Filed: 1934-04-21
Abstract: 441,573. CrÛpe threads. DREYFUS, H., 22, Hanover Square, London. April 21, 1934, No. 8912. [Class 120 (iii)] In the production of highly twisted crÛpe threads from filaments of cellulose esters or ethers, at least the last part of the crÛpe twist is applied while the material of the thread is in a softened state. The desired temporary softening of the filaments may be effected by means of organic liquids which may be volatile, by means of aqueous liquids containing substances which impart to the liquid a softening action and which may be organic solvents or swelling agents for the cellulose esters or ethers or inorganic agents having a swelling action thereon. The liquids may be employed hot or cold and under pressure and may contain substances which facilitate the wetting of the threads by the liquid. Vapours of organic substances may also be employed for effecting the desired softening of the filaments and may be saturated or supersaturated or employed in the presence of the substance in liquid form, e.g. by wetting the thread with the liquid softening agent, and the vapours may be employed at pressures below, at, or. above that of the atmosphere. Steam may be used in conjunction with the softening agent. The filaments may be softened by heat and without the use of a substance which itself has a softening action on the material of the filaments, e.g. a heated gas or a superheated vapour may be used. The softening agent may be incorporated in the threads in an operation separate from the crÛpe twisting operation, e.g. by impregnating the packages of thread or a high boiling softening agent may be incorporated in the spinning solution which is spun by a dry-spinning process. Twisting may be effected by drawing the thread off over the end of a rotating package through a guide fixed substantially in line with the axis of rotation of the package or by the use of a ring twister, the means for applying the softening agent and the twisting spindle being arranged so that the last part at least of the twist is inserted while the thread is in a softened state; the ballooning of the thread may be restricted by the device described in Specification 304,806, [Class 120 (ii)]. When liquid softening agents are employed the thread may be drawn upwards through a small hole into the liquid contained in a suitable receptacle provided with means to lead the liquid issuing from the hole away and prevent it from reaching the twisting spindle, and the hole may take the form of a short tube of fine bore fixed in the receptacle ; the liquid may be supplied to the thread by passing it in contact with a wick or a grooved or other roller taking liquid from a bath and when using hot liquids, the liquid may be applied to the thread in a heated state or applied at a lower temperature and the thread heated, e.g. by passage through a heated chamber. When vapours are employed, one or more chambers supplied with vapour inlets and small holes for the passage of the thread may be used ; the vapour may be arranged to condense in the device so that the vapour is employed in the presence of the liquid or the thread may be moistened with the liquid, e.g. by a wick, before entering the vapour treatment device. The thread may be initially twisted to a small degree and the crepe twist may be applied in one or more stages, the final stage of twisting being effected while the material of the thread is in a softened state ; one or more of the earlier stages of twisting may also be effected while the thread is in a softened state. The minimum crÛpe twist depends on the denier of the thread and the stretch imparted to the filaments of the threads by the crepe twisting is of the order of 5 to 25 per cent of their original length. The crÛpe threads may be made from filaments that have been stretched while in a softened state, e.g. as described in Specifications 277,089, 323,790, [both in Class 2 (ii)], 370,430, 371,461 ; 438,584, 438,585, 438,586, 438,587, 438,655, and 438,656, [all in Group IV], and may contain substantially continuous filaments or may be spun from a mass of discontinuous filaments (staple fibre) or those prepared in the manner described in Specifications 424,683, 424,752, 424,830, and 424,879. The threads may consist of or contain cellulose ester filaments which have been superficially saponified or have been partially saponified throughout and the saponincation may be effected intermittently along the length of the threads. The threads may be composed in part of filaments of one ester or ether of cellulose and in part of filaments of another ester or ether of cellulose or in part of filaments of a cellulose ester or ether and in part of filaments of another material. The threads may be sized uniformly or intermittently along their length at any suitable stage of their manufacture ; the sizing materials may be those selected in accordance with the description in Specification 348,589. The thread may be wetted before or during the application of the crÛpe twist. Specifications 437,019, 438,589,438,590, 438,591, and 438,654 also are referred to. Reference has been directed by the Comptroller to Specifications 386,344 and 386,374.