Method for making yarns, fibres and filaments

Abstract

The invention concerns a method for making yarns, fibres and filaments based on polyamide, and yarns, fibres and filaments obtainable by said method. The invention concerns a method for making yarns, fibres and filaments based on a polyamide composition having a molecular structure for enhancing overall productivity of the spinning process, in particular by improving the capacity for drawing the yarns produced thereby providing, for example, for a single identical spinning speed a much higher yarn meterage produced per time unit after drawing. The invention consists in a method for making synthetic yarns, fibres and filaments based on polyamide, comprising the following steps: i) mixing in molten phase the following compounds A and B: compound A: a linear polyamide; compound B selected in the group comprising: star-shaped or H-shaped macromolecular chains including one or several cores and at least three polyamide branches or three polyamide segments bound to said core, obtained from amino acid monomers and/or lactams, and as the case may be linear polyamide macromolecular chains obtained from amino acid monomers and/or lactams the melt index in molten phase of the polyamide or of the polyamide composition measured in accordance with the ISO 1133 standard at 275° C. under 100 g load being higher than 20 g/10 min, and a multifunctional compound comprising at least three identical acid or amine functions; ii) spinning the mixture in molten phase; iii) and optionally drawing said resulting yarns, fibres or filaments.

1 . Process for manufacturing synthetic, polyamide-based yarns, fibers and filaments, comprising the following operations: 
 i) Blending, in the melt, at least one of the compounds A and B below: 
 compound A: a linear polyamide  
 compound B chosen from the group comprising: 
 a polyamide or a polyamide composition comprising: 
 starburst or H-shaped macromolecular chains comprising one or more cores and at least three polyamide branches or three polyamide segments linked to the said core, obtained from amino acid and/or lactam monomers,  
 where appropriate, linear polyamide macromolecular chains obtained from amino acid and/or lactam monomers,  
 the melt flow index of the polyamide or of the polyamide composition measured according to ISO standard 1133 at 275° C. under a 100 g charge being greater than 20 g/10 min, and  
 
 a multifunctional compound comprising at least three identical acid or amine functions,  
 
   ii) spinning the blend in the melt, and    iii) optionally drawing the said yarn(s), fiber(s) or filament(s) obtained.    
     
     
         2 . Process according to  claim 1 , characterized in that the weight ratio between the starburst or H-shaped macromolecular chains and the sum of the starburst or H-shaped macromolecular chains and of the linear chains in compound B is between 0.1 and 1.  
     
     
         3 . Process according to either of the preceding claims, characterized in that compound B is a starburst polyamide obtained by copolymerization using a monomer blend comprising: 
 a) a multifunctional compound comprising at least three reactive functions chosen from amines, carboxylic acids and derivatives thereof, the reactive functions being identical,    b) monomers of general formulae (IIa) and/or (IIb) below:   X—R 2 —Y  (IIa)   or                          c) optionally, monomers of general formula (III) below:   Z—R 3 —Z  (III)   in which: 
 Z represents a function that is identical to that of the reactive functions of the multifunctional compound  
 R 2  and R 3 , which may be identical or different, represent substituted or unsubstituted, aliphatic, cycloaliphatic or aromatic hydrocarbon-based radicals containing from 2 to 20 carbon atoms, and possibly comprising hetero atoms,  
 Y is a primary amine radical when X represents a carboxylic radical, or  
 Y is a carboxylic radical when X represents a primary amine radical.  
   
     
     
         4 . Process according to either of claims  1  and  2 , characterized in that compound B is an H-shaped polyamide obtained by copolymerization using a monomer blend comprising: 
 a) 1 to 50 μmol per gram of polymer of compound B of a multifunctional compound comprising at least three reactive functions chosen from amines, carboxylic acids and derivatives thereof, the reactive functions being identical,  
 b) lactams and/or amino acids  
 c) a difunctional compound chosen from dicarboxylic acids and diamines,  
 d) a multifunctional compound whose function is chosen from amines, carboxylic acids and derivatives thereof, the functions of c) and d) being amines when the functions of a) are acids, the functions of c) and d) being acids when the functions of a) are amines, the ratio in equivalents between the functional groups of a) and the sum of the functional groups of c) and d) being between 1.5 and 0.66, the ratio in equivalents between the functional groups of c) and the functional groups of d) being between 0.17 and 1.5.  
 
     
     
         5 . Process according to either of claims  1  and  2 , characterized in that compound B is obtained by extruding a polyamide of the type obtained by polymerization of lactams and/or amino acids with a multifunctional compound comprising at least three reactive functions chosen from amines, carboxylic acids and derivatives thereof, the reactive functions being identical.  
     
     
         6 . Process according to one of  claims 3  to  5 , characterized in that the multifunctional compound has an arborescent or dendritic structure.  
     
     
         7 . Process according to one of  claims 3  to  5 , characterized in that the multifunctional compound is represented by formula (I) 
       R1A—z] m   (I) 
       in which: 
 R 1  is a linear or cyclic, aromatic or aliphatic hydrocarbon-based radical containing at least two carbon atoms and possibly comprising hetero atoms,  
 A is a covalent bond or an aliphatic hydrocarbon-based radical containing from 1 to 6 carbon atoms,  
 Z represents a primary amine radical or a carboxylic group,  
 m is an integer between 3 and 8.  
 
     
     
         8 . Process according to  claim 7 , characterized in that the multifunctional compound is chosen from 2,2,6,6-tetra(P-carboxyethyl)cyclohexanone, trimesic acid, 2,4,6-tri(aminocaproic acid)-1,3,5-triazine and 4-aminoethyl-1,8-octanediamine.  
     
     
         9 . Process according to one of the preceding claims, characterized in that the weight proportion of compound B in the blend relative to the total weight of compounds A and B is less than 30%.  
     
     
         10 . Process according to  claim 9 , characterized in that the weight proportion of compound B in the blend relative to the total weight of compounds A and B is less than 20%.  
     
     
         11 . Process according to  claim 10 , characterized in that the weight proportion of compound B in the blend relative to the total weight of compounds A and B is less than 15%.  
     
     
         12 . Process according to one of the preceding claims, characterized in that the weight proportion of starburst or H-shaped macromolecular chains of compound B in the blend relative to the total weight of compounds A and B is less than 25%.  
     
     
         13 . Process according to one of the preceding claims, characterized in that the weight proportion of starburst or H-shaped macromolecular chains of compound B in the blend relative to the total weight of compounds A and B is less than 15%.  
     
     
         14 . Process according to one of the preceding claims, characterized in that compound A is a polyamide chosen from nylon-6, nylon-11, nylon-12 and blends and copolymers based on these polyamides.  
     
     
         15 . Process according to one of the preceding claims, characterized in that compound A is a nylon-6 with a relative viscosity of greater than 3.5.  
     
     
         16 . Process according to one of  claims 1  to  13 , characterized in that compound A is a linear polyamide obtained from diacid monomers and diamine monomers.  
     
     
         17 . Process according to  claim 16 , characterized in that compound A is a nylon-6,6 obtained from adipic acid and hexamethylenediamine.  
     
     
         18 . Process according to either of claims  16  and  17 , characterized in that compound A is a copolyamide comprising at least 90 mol % of hexamethylenediamine adipate repeating units.  
     
     
         19 . Process according to one of the preceding claims, characterized in that a compound capable of catalysing the polycondensation of the polyamide is added to the blend, compounds A and B being in dried form.  
     
     
         20 . Process according to one of the preceding claims, characterized in that the spinning is performed with a spinning speed of greater than 3 500 m/min.  
     
     
         21 . Yarns, fibers and filaments that may be obtained by a process according to one of the preceding claims.  
     
     
         22 . Yarns, fibers and filaments that may be obtained by the process according to one of  claims 1  to  20 , characterized in that the monofilament yarn count is less than 0.8 dtex and preferably less than 0.6 dtex.