There is provided a synthetic polymer fibre having an amorphous phase of at least 10% of the crystallinity ratio. The synthetic polymer fibre includes 0.1 to 5.0 wt. % of a biodegradation—inducing additive with respect to the total weight of the synthetic polymer fibre. The biodegradation-inducing additive is incorporated in the amorphous phase such that the biodegradation-inducing additive is physically and/or chemically accessible for a biodegradation initiation to form nuclei of biodegradation within the amorphous phase.

A method for fusing aramid fibers, wherein a) at least one area of an aramid fiber is treated with an ionic liquid so that the aramid is partially dissolved, b) the aramid fiber is contacted via the dissolved area with another aramid fiber area with pressure being applied to the contact area, and subsequently c) the partially dissolved area of the aramid is re-coagulated.

Provided is a down-proof woven fabric which is highly effective to prevent leakage of down from a seam of a product, even having a low cover factor, the woven fabric containing a single yarn having a convex portion and a concave portion in a cross section, in which an air permeability is 0.1 cm.sup.3/cm.sup.2.Math.s or more and 2.0 cm.sup.3/cm.sup.2.Math.s or less; a total fineness is 5 dtex or more and 80 dtex or less; a total cover factor of a warp and a weft is 1500 or more and 2200 or less; a hole is formed in the woven fabric with a sewing machine needle having a cross-sectional diameter (thickness of a main body of the sewing machine needle) of 1.00 mm, and in an area having a radius of 1.5 mm about the hole, a total number of warps and wefts that are displaced by 0.08 mm or more with the sewing machine needle is 3 or less at 15 minutes after the sewing machine needle is pulled out from the woven fabric; and the following characteristics: (i) a fitting ratio of single yarns is 10% or more and 80% or less (ii) a laminating rate of the single yarn is 0.4 or more and 3.0 or less (iii) a number of convex portions of the single yarn is 2 or more and 12 or less (iv) the single yarn has a modification degree of 1.2 or more and 3.0 or less (v) a concave portion of the single yarn has a depth of 0.6 μm or more and 8 μm or less
CF=CF.sub.T+CF.sub.W where CF represents the total cover factor of the warp and the weft; CF.sub.T represents a cover factor of the warp; and CF.sub.W represents the cover factor of the weft.

An artificial hair fiber is superior in productivity and flame retardance, and is suppressed in color unevenness. An artificial hair fiber, including polyamide; and 5 to 40 parts by mass of bromine flame retardant and 0.01 to 10 parts by mass of pigment processing pigment with respect to 100 parts by mass of the polyamide; wherein the pigment processing pigment includes a colorant and a dispersant; the dispersant is contained by 20 to 80 mass % with respect to 100 mass % of total amount of the colorant and the dispersant; the dispersant includes one or more selected from the group consisting of montanoic acid metallic salt, montanoic acid wax, polyethylene wax, and fluorine wax, is provided.

The present disclosure provides fibers and filaments formed from polyamide polymers polymerized with dual termination of the amino and carboxyl end-groups, referred to herein as dual-terminated polyamides, or dual terminated PA. In one embodiment, the dual-terminated polyamide is considered “highly terminated” and is useful in producing stain resistant textiles such as carpet fibers, for example.

The present disclosure provides fibers and filaments formed from polyamide polymers polymerized with dual termination of the amino and carboxyl end-groups, referred to herein as dual-terminated polyamides, or dual terminated PA. In one embodiment, the dual-terminated polyamide is considered “highly terminated” and is useful in producing stain resistant textiles such as carpet fibers, for example.

A fiber for artificial hair constituted of a resin composition containing an aliphatic polyamide. A weight average molecular weight Mw of a dissolved component obtained when the fiber for artificial hair is dissolved in hexafluoroisopropanol is 46,000 or more and less than 65,000.

A fiber for artificial hair constituted of a resin composition containing an aliphatic polyamide. A weight average molecular weight Mw of a dissolved component obtained when the fiber for artificial hair is dissolved in hexafluoroisopropanol is 46,000 or more and less than 65,000.

The invention is related to an improved fiber and articles comprising the improved fibers. The fiber comprises: 90 wt % to 99.99 wt % thermoplastic resin; and 0.01 wt % to 10 wt % additive is defined by Formula (I):

##STR00001## wherein: Ar is selected from the group consisting of aryl, monosubstituted aryl and polysubstituted aryl, heteroaryl, monosubstituted heteroaryl and polysubstituted heteroaryl; Ar.sup.1 and Ar.sup.2 are independently selected from the group consisting of aryl, monosubstituted aryl and polysubstituted aryl, heteroaryl, monosubstituted heteroaryl and polysubstituted heteroaryl; R.sup.1 and R.sup.2 are independently an alkylene radical having 2-20 carbon atoms; and n and m are independently 1-20.

The invention is related to an improved fiber and articles comprising the improved fibers. The fiber comprises: 90 wt % to 99.99 wt % thermoplastic resin; and 0.01 wt % to 10 wt % additive is defined by Formula (I):

##STR00001## wherein: Ar is selected from the group consisting of aryl, monosubstituted aryl and polysubstituted aryl, heteroaryl, monosubstituted heteroaryl and polysubstituted heteroaryl; Ar.sup.1 and Ar.sup.2 are independently selected from the group consisting of aryl, monosubstituted aryl and polysubstituted aryl, heteroaryl, monosubstituted heteroaryl and polysubstituted heteroaryl; R.sup.1 and R.sup.2 are independently an alkylene radical having 2-20 carbon atoms; and n and m are independently 1-20.