High speed melt spinning of fibers

Abstract

Thermoplastics may be melt spun at high production rates, and without physical property degradation, by spinning a blend of the thermoplastic and a minor amount of a specified liquid crystalline polymer.

What is claimed is:  
     
         1 . A process for the melt spinning of one or more thermoplastics at windup speeds of about 1000 m/minute or more, wherein the improvement comprises, spinning said thermoplastic or thermoplastics as a blend which contains about 0.1 to about 10 percent by weight of a liquid crystalline polymer, said percentage based on a total amount of said thermoplastic or thermoplastics present plus said liquid crystalline present, 
 and provided that said liquid crystalline polymer consists essentially of repeat of the formula: 
 (I) at least one repeat unit selected from the group consisting of  
                     
 (III) at least one repeat unit selected from the group consisting of  
                     
   wherein: 
 a molar ratio of (II) to (III) ranges from about 25:75 to about 90:10;  
 a molar ratio of (I) to [(II)+(III)] is substantially 1:1;  
 a molar ratio of (IV) to (V) ranges from about 97:3 to about 50:50;  
 a number of moles of (IV) plus (V) ranges from about 100 to about 600 per 100 moles of (I); and  
   wherein (I), (II), (III), (IV), (V) and (VI) are in units of moles.    
     
     
         2 . The process as recited in  claim 1  wherein said thermoplastic is a polyester or a polyamide.  
     
     
         3 . The process as recited in  claim 1  wherein said thermoplastic is poly(ethylene terephthalate).  
     
     
         4 . The process as recited in  claim 1  wherein said thermoplastic is one or both of nylon-6,6 and nylon-6.  
     
     
         5 . The process as recited in  claim 1  wherein in said liquid crystalline polymer, repeat unit (I) consists essentially of (IA) and (IB) and the molar ratio of (IA) to (IB) is about 75:25 to about 25:75, the molar ratio of (II):(III) is about 30:70 to about 85:15, the molar ratio of (IV):(V) is about 50:50 to about 90:10, the number of moles of (IV) plus (V), per 100 moles of (I), is about 200 to about 500.  
     
     
         6 . The process as recited in  claim 1  wherein said thermoplastic is poly(1,3-propylene terephthalate).  
     
     
         7 . The process as recited in  claim 1 ,  2 ,  3 ,  4 ,  5  or  6  wherein about 0.5 to about 5 percent of said liquid crystalline polymer is present.  
     
     
         8 . A composition, comprising: 
 (a) from about 99.9 to about 90 percent by weight of a thermoplastic;    (b) from about 0.1 to about 10 percent by weight of a liquid crystalline polymer consisting essentially of repeat units of the formula: 
 (I) at least one repeat unit selected from the group consisting of  
                     
 (III) at least one repeat unit selected from the group consisting of  
                     
   wherein: 
 a molar ratio of (II) to (III) ranges from about 25:75 to about 90:10;  
 a molar ratio of (I) to [(II)+(III)] is substantially 1:1;  
 a molar ratio of (IV) to (V) ranges from about 97:3 to about 50:50;  
 a number of moles of (IV) plus (V) ranges from about 100 to about 600 per 100 moles of (I); and  
   wherein (I), (II), (III), (IV), (V) and (VI) are in units of moles, and said percent by weight of (a) and said percent by weight of (b) are based on the total amount of (a) and (b) present.    
     
     
         9 . The composition as recited in  claim 8  wherein said thermoplastic is a polyester or a polyamide.  
     
     
         10 . The composition as recited in  claim 8  wherein said thermoplastic is poly(ethylene terephthalate).  
     
     
         11 . The composition as recited in  claim 8  wherein said thermoplastic is one or both of nylon-6,6 and nylon-6.  
     
     
         12 . The composition as recited in  claim 8  wherein in said liquid crystalline polymer, repeat unit (I) consists essentially of (IA) and (IB) and the molar ratio of (IA) to (IB) is about 75:25 to about 25:75, the molar ratio of (II):(III) is about 30:70 to about 85:15, the molar ratio of (IV):(V) is about 50:50 to about 90:10, the number of moles of (IV) plus (V), per 100 moles of (I), is about 200 to about 500.  
     
     
         13 . The composition as recited in  claim 8 ,  9 ,  10 ,  11 , or  12  wherein about 0.5 to about 5 percent of said liquid crystalline polymer is present.  
     
     
         14 . The composition as recited in  claim 7 ,  8 ,  9 ,  10 ,  11 , or  12  in the form of a fiber.  
     
     
         15 . The composition as recited in  claim 11  in the form of a fiber.