Colored synthetic fiber

Abstract

The present invention relates to the field of polymers, in particular that of polyester fibers, and relates more specifically to a process for manufacturing a colored synthetic fiber, and to the uses thereof. More particularly, the present invention relates to a process for manufacturing a colored synthetic fiber from a semicrystalline thermoplastic polyester based on isosorbide, said fiber being colored by means of an aqueous solution of at least one disperse dye. The present invention also relates to a fiber colored by a disperse dye and also to the use thereof in the field of furnishings, textiles or sporting goods. The process according to the invention makes it possible to obtain colored synthetic fibers having improved quality and improved stability of the dyeing.

1 . A process for manufacturing a colored synthetic fiber comprising the following steps of:
 1) providing a semicrystalline thermoplastic polyester comprising at least one 1,4:3,6-dianhydrohexitol unit (A), at least one aliphatic diol unit (B) other than the 1,4:3,6-dianhydrohexitol units (A), and at least one aromatic dicarboxylic acid unit (C), wherein the (A)/[(A)+(B)] molar ratio is at least 0.05 and at most 0.30, the reduced viscosity in solution (35° C.; ortho-chlorophenol; 5 g/l of polyester) of which is greater than 50 ml/g;   2) preparing the synthetic fiber from said semicrystalline thermoplastic polyester; and   3) dyeing said synthetic fiber with an aqueous solution of at least one disperse dye.   
     
     
         2 . The process according to  claim 1 , wherein the disperse dye is selected from azo-type dyes, anthraquinone-type disperse dyes, methine-type dyes, nitro-type dyes, naphthoquinone-type dyes, aminoketone-type dyes and mixtures thereof. 
     
     
         3 . The process according to  claim 2 , wherein the disperse dye is an azo dye selected from the di-azo dyes or the mono-azo dyes derived from azobenzene. 
     
     
         4 . The process according to  claim 1 , wherein the aqueous solution of disperse dye used for the dyeing step has a temperature of 120° C. to 140° C., preferably 130° C., and a pH of 3.5 to 5.5, preferably of 4 to 5. 
     
     
         5 . The process according to  claim 1 , wherein the 1,4:3,6-dianhydrohexitol unit (A) is selected from isosorbide, isomannide, isoidide, or one of the mixtures thereof, preferably, the unit (A) is isosorbide. 
     
     
         6 . The process according to  claim 1 , wherein the aliphatic diol unit (B) is 1,4-cyclohexanedimethanol. 
     
     
         7 . The process according to  claim 1 , wherein the aromatic dicarboxylic acid unit (C) is terephthalic acid. 
     
     
         8 . The process according to  claim 1 , wherein the semicrystalline thermoplastic polyester is free of non-cyclic aliphatic diol unit or comprises a molar amount of non-cyclic aliphatic diol units, with respect to the total number of monomer units of the polyester, of less than 1%; preferably, the polyester is free of non-cyclic aliphatic diol unit. 
     
     
         9 . The process according to  claim 1 , wherein the preparation step of the synthetic fiber is carried out by the melt spinning method or by wet or dry solution processes. 
     
     
         10 . A synthetic fiber colored by a disperse dye, said synthetic fiber consisting substantially of a semicrystalline thermoplastic polyester comprising at least one 1,4:3,6-dianhydrohexitol unit (A), at least one aliphatic diol unit (B) other than the 1,4:3,6-dianhydrohexitol units (A), at least one aromatic dicarboxylic acid (C), wherein the (A)/[(A)+(B)] molar ratio is at least 0.05 and at most 0.30, the reduced viscosity in solution (35° C.; ortho-chlorophenol; 5 g/l of polyester) of which is greater than 50 ml/g. 
     
     
         11 . Use of the synthetic fiber as defined according to  claim 10 , in the field of furnishings, textiles or sporting goods.