Patent ID: 9243350
Filing Date: 2016-01-26
CPC Classification: D01F,D06P

Claim Text:
1. A meta-type wholly aromatic polyamide fiber comprising a UV absorber with a water solubility of less than 0.04 mg/L, and having: a crystallinity of 5 to 20%; a degree of dye exhaustion of 90% or more in the form of a dyed fiber; and a light resistance retention of 80% or more after carrier dyeing; wherein the degree of dye exhaustion is measured by the following method: (i) to a residual dyeing liquid that has dyed the fiber before dyeing (raw fiber), the same volume of dichloromethane as the residual dyeing liquid is added to extract the residual dye; (ii) subsequently, the absorbance of the extract is measured at wavelengths of 670 nm, 540 nm, and 530 nm, and the dye concentration of the extract at each wavelength is calculated from calibration curves for the above three wavelengths previously prepared using a dichloromethane solution having a known dye concentration; (iii) the average of the concentrations at the above three wavelengths is taken as the dye concentration of the extract (C); and (iv) a value obtained by the following equation 4 using the dye concentration before dyeing (Co) is defined as the degree of dye exhaustion (U): and wherein the light resistance retention is measured by the following method: (i) resistance to light-induced discoloration and fading (ΔE*) is determined using light-irradiated staple fiber that has been irradiated in a carbon arc fade meter at 63° C. for 24 hours and unirradiated staple fiber, wherein resistance to light-induced discoloration and fading (ΔE*) is calculated as follows: and (ii) light resistance retention is a value calculated by the following equation 6 using the resistance to light-induced discoloration and fading (ΔE*) of staple fiber before and after dyeing: