Abstract: A composite fiber is described which comprises a polyester component and a polyamide component bound in a side-by-side or eccentric core-in-sheath structure, exhibiting a percentage of crimp DC of 1.3-15.0% after the composite fiber is treated in boiling water for 30 minutes under a load of 1.76×10?3 cN/dtex, and then dry heat treated for 30 minutes at 100° C. under a load of 1.76×10?3 cN/dtex, for stabilization of the crimps and further dry heat treated for one minute at 160° C. under a load of 1.76×10?3 cN/dtex, as well as a percentage of crimp HC of 0.5-10% after immersion in water at 20-30° C. for 10 hours, and a difference ?C of 0.5-7.0% between the percentage of crimps.

Abstract: A conjugate fiber-containing yarn containing side-by-side or eccentric core-in-sheath conjugate fibers each composed of a polyester component and a polyamide component, that can be crimped by heating, and that has properties of increasing its crimp ratio when it absorbs moisture or water and is excellent in windbreaking and warmth-retaining properties, has a wool-like soft and bulky hand, and is capable of forming a fabric in which a see-through property is not increased even when wetted with water.

Abstract: A composite fiber which expresses crimping and whose percentage of crimp varies reversibly in response to humidity, which maintains excellent variation properties in percentage of crimp even after the processes of dyeing and finishing, and which is highly practical and can easily yield comfortable fabrics with reduced stuffy feeling. The composite fiber comprises a polyester component and a polyamide component bound in a side-by-side or eccentric core-in-sheath structure, exhibiting a percentage of crimp DC of 1.3-15.0% after the composite fiber is treated in boiling water for 30 minutes under a load of 1.76×10?3 cN/dtex, and then dry heat treated for 30 minutes at 100° C. under a load of 1.76×10?3 cN/dtex for stabilization of the crimps and further dry heat treated for one minute at 160° C. under a load of 1.76×10?3 cN/dtex, as well as a percentage of crimp HC of 0.5-10% after immersion in water at 20-30° C. for 10 hours, and a difference ?C of 0.5-7.0% between the percentage of crimps.

Abstract: A woven or knit fabric containing crimped composite fibers having its air permeability enhanced by water wetting and being useful in clothes such as outerwear, which woven or knit fabric contains 10 to 100 mass % of composite fibers of side-by-side type or eccentric core sheath type composed of polyester resin component and polyamide resin component whose thermal shrinkages are different from each other, the composite fibers having crimps developed by heat treatment. The composite fibers exhibit humid crimp factor HCF (%), as measured through a procedure comprising immersing the same in water of 30° C. for 2 hr, pulling them up, interposing them between a pair of filter papers at 30° C. in a humidity of 90% RH within 60 sec of the pulling up and applying a pressure of 0.69 mN/cm2 for 5 sec, of ?10% lower than the dry crimp factor DCF (%) after dying by allowing them to stand still at 20° C.

Abstract: A woven or knitted fabric with a air space which is reversibly decreased by wetting with water compared to its dry state, comprises crimped filaments A whose percentage of crimp decreases upon wetting with water, and filaments B selected from among filaments with no crimps and crimped filaments which undergo substantially no change in percentage of crimp upon wetting with water, wherein the difference between the dry percentage of crimp DCf(%) and the wet percentage of crimp (HCf) (DCf?HCf) of a crimped filament A taken from the woven or knitted fabric is at least 10%, and the average value RA between the change in dimensions RP(%) of the woven or knitted fabric in the warp (or wale) direction when wet and when dry, and the change in dimensions RF(%) in the weft (or course) direction when wet and when dry (=(RP?RF)/2)(%) is at least 5%.

Abstract: A woven or knitted fabric, having a roughness which is manifested when wetted with water and disappears when dried, comprises crimped filaments A whose percentage of crimp decrease when wetted with water, and filaments B composed of non-crimped filaments and/or crimped filaments which undergo substantially no change in percentage of crimp when wetted with water, wherein the change of the roughness is 5% or more, determined in accordance with the following equation: Change in Roughness (%)=((TW?TD)/TD)×100 in which TD: a thickness upon drying and TW: a thickness upon wetting with water, of the woven or knitted fabric.

Abstract: A polyamide fiber comprised of (A) a thermoplastic aliphatic polyamide having copolymerized therein a polyalkylene oxide unit and having a melting point of at least 160.degree. C., and (B) a polyoxyalkylene glycol, wherein the ingredient (B) is finely dispersed in the ingredient (A). A polyamide fiber exhibiting a rate of moisture absorption of at least 3.5%/5 minutes at 25.degree. C. and R.H. 90% and/or a triboelectric voltage of not larger than 1.5 kV at 20.degree. C. and R.H. 40% is obtained by removing the ingredient (B) from the above-mentioned polyamide fiber by means of dissolution.

Abstract: A synthetic polymer multifilament yarn capable of being converted to a bulky yarn is composed of a plurality of irregular individual filaments each having at least two belt-shaped filamentary constituents, at least one core filamentary constituent located between the belt-shaped constituents and extending in a sinuous manner and having a thickness varying alternately between thick and thin, and at least two thin middle filamentary constituents located between the core constituent and the belt-shaped constituents to thereby connect those constituents to each other.

Abstract: A synthetic polymer hollow irregular multifilament yarn useful for producing bulky yarn products comprises a plurality of hollow irregular individual filaments each comprising a hollow filamentary constituent, a non-hollow sinuous filamentary constituent sinuously extending in a wave form along the hollow filamentary constituent, having a smaller average thickness than the hollow filamentary constituent and being connected to one side of the hollow filamentary constituent through a middle filamentary constituent distortedly extending along the hollow filamentary constituent and having a cross-sectional profile in the form of a waist, and is produced by extruding at least one polymer melt through a spinneret having a plurality of spinning orifices each consisting of a first orifice segment adequate for forming a hollow filament, a second orifice segment adequate for forming a non-hollow filament and having a smaller cross-section than that of the first orifice segment and a third orifice segment in the form of

Abstract: A synthetic polymer hollow irregular multifilament yarn useful for producing bulky yarn products comprises a plurality of hollow irregular individual filaments each comprising a hollow filamentary constituent, a non-hollow sinuous filamentary constituent sinuously extending in a wave form along the hollow filamentary constituent, having a smaller average thickness than the hollow filamentary constituent and being connected to one side of the hollow filamentary constituent through a middle filamentary constituent distortedly extending along the hollow filamentary constituent and having a cross-sectional profile in the form of a waist, and is produced by extruding at least one polymer melt through a spinneret having a plurality of spinning orifices each consisting of a first orifice segment adequate for forming a hollow filament, a second orifice segment adequate for forming a non-hollow filament and having a smaller cross-section than that of the first orifice segment and a third orifice segment in the form of