| 摘要 |
Yarn containing keratinous fibres is crimped by twisting the yarn, setting the twist by treatment with a reducing agent, and then untwisting at least some of the imposed twist. Keratinous fibres mentioned are various animal wools and they may be blended with non-keratinous fibres, for example cotton, rayon, cellulose acetate and triacetate, vinyl, acrylic, polyamide and polyester fibres, to produce a single or multi-ply yarn to be crimped. The imposed twist may be in the same direction as, or in the opposite direction to, the original twist in the yarn while the back twist may be greater or less than the imposed twist. In an example the yarn is twisted and wound on to a perforated dye spindle which is immersed in an aqueous solution containing 1% sodium bisulphite. After ten minutes excess reducing agent is drained from the yarn and the yarn is then steamed for a further ten minutes. The yarn is then rinsed, optionally dyed, dried in an oven at 80 DEG C, and then entwisted on to another bobbin. If the yarn has been stretched on a bobbin for an extended time it has little tendency to retract unless exposed to steaming or wetting. The retracted yarn has either a helical or random configuration depending on the degree of twist in the set state. The yarn may be plied with a similar elastic yarn or with a non-elastic yarn comprising keratinous and/or non-keratinous fibres. Reducing agents listed include lower alkanolamine sulphites; metallic formaldehyde sulphoxylates; alkali metal sulphoxylates, borohydrides, and sulphites; sodium sulphide, hydrosulphide, hypophosphite, thiosulphate, and dithionate; ammonium bisulphite; cysteine hydrochloride; titanous chloride; sulphurous acid; and mercaptan acids, salts, and glycols, and alkyl mercaptans. Swelling agents -for example urea-and low molecular weight (> 4000) polyhydroxy compounds-for example ethylene glycol, may added to the reducing agent. |
