Process for the production of a crimped continuous multifilament yarn

Abstract

Process and apparatus for producing a crimped continuous multifilament yarn by the sequential steps of air-jet texturizing to form multiple random filamentary loops, immediately pulling out metastable loops formed in the yarn without heating and without stretching or deforming the yarn filaments, next shrinking and heat setting the yarn at a temperature of about 150°-245° C., and then winding the yarn onto a spool at a predetermined yarn tension. The resulting spooled texturized yarn has valuable properties and characteristics in subsequent processing and textile operations.

The invention is hereby claimed as follows: 
     
       1. A process for the production of a linearly stable, crimped continuous multifilament yarn which comprises: guiding the initial non-crimped multifilament yarn between a first and second delivery system through an air-jet texturizing nozzle as a texturizing zone at .Iadd.a temperature insufficient to heat set the yarn and at .Iaddend.an overfeed rate corresponding to a circumferential speed V 2  of the second delivery system which is less than the circumferential speed V 1  of the first delivery system, thereby forming multiple random loops in the individual filaments including a minor proportion of metastable loops;   .Iadd.eliminating or at least pulling out to a stable position a predominant number of said metastable loops without removing the other random loops and without any elastic or plastic deformation of the individual filaments by .Iaddend.conducting the yarn immediately after it has left the texturizing zone into a heat-free stabilizing zone by means of a third delivery system having a run-out speed V 3  greater than the run-in speed V 2  of the second delivery system.[., such that metastable loops are pulled out of the yarn without causing any elastic or plastic deformation of the individual filaments.].;   then conducting the stabilized yarn into a setting zone by means of a fourth delivery system having a run-out circumferential speed V 4  which allows a .Iadd.controlled .Iaddend.shrinkage of the yarn to a predetermined amount, the yarn in said setting zone being subjected to a shrinking treatment and heat treatment at temperatures from 150° C. up to about 245° C.; and   winding the yarn after said shrinkage onto a spool at a predetermined yarn tension and at a winding speed V 5  which is less than V 1 .   
     
     
       2. A process as claimed in claim 1 wherein the run-out speed V 3  from the stabilizing zone is less than the run-in speed V 1  into the texturizing zone. 
     
     
       3. A process as claimed in claim 1 wherein the winding speed V 5  is less than V 2 . 
     
     
       4. A process as claimed in claim 1 wherein the run-in speed V 1  into the texturizing zone is up to 300% greater than the run-out speed V 2  from said texturizing zone. 
     
     
       5. A process as claimed in claim 1 wherein the run-in speed V 1  into the texturizing zone is up to 25% greater than the run-out speed V 2  from said texturizing zone. 
     
     
       6. A process as claimed in claim 1 wherein the run-out speed V 3  from the stabilizing zone is 2 to 30% greater than the run-in speed V 2  into said stabilizing zone. 
     
     
       7. A process as claimed in claim 1 wherein the run-out speed V 3  from the stabilizing zone is 2 to 15% greater than the run-in speed V 2  into said stabilizing zone. 
     
     
       8. A process as claimed in claims 1, 6 or 7 wherein the run-out speed V 4  of the setting zone is about 2 to 10% less than the run-out speed V 3  of the stabilizing zone. 
     
     
       9. A process as claimed in claim 1 wherein the run-out speed V 4  of the setting zone is less than the run-in speed V 3  of said setting zone. 
     
     
       10. A process as claimed in claim 9 for producing a low shrinkage yarn having a linear density higher than 70 dtex wherein the run-out speed V 4  of the setting zone is less than the run-in speed V 2  of the stabilizing zone. 
     
     
       11. A process as claimed in claim 1 wherein the winding speed V 5  is approximately equal to the run-out speed V 4  of the setting zone but less than the run-out speed V 3  of the stabilizing zone. 
     
     
       12. A process as claimed in claim 1 wherein the pulling out of the yarn in the stabilizing zone is less than the change in length of the same yarn if it were to be subjected to the shrinking and heat treatment immediately after the texturizing zone and then subjected to a weight load of 0.3 g/den for 30 seconds duration. 
     
     
       13. A process as claimed in claim 1 wherein the yarn being used is a multifilament yarn of polyethylene terephthalate. 
     
     
       14. A process as claimed in claim 1 wherein the yarn being used is a multifilament yarn of polyethylene terephthalate which has been spun at a spinning speed of more than 2,500 m/min and subsequently stretched in the ratio of 1:1.2 to 1:2 before being introduced into the texturizing zone. 
     
     
       15. A process as claimed in claims 13 of 14 wherein the yarn has a linear density on the order of 167 dtex. 
     
     
       16. A process as claimed in claims 13 or 14 wherein the yarn has a linear density on the order of 267 dtex. 
     
     
       17. A process as claimed in claim 1 wherein a number of yarns from identical texturizing and stabilizing zones are combined into a two-ply or three-ply yarn with an identical shrinking and heat treatment of the individual yarns. 
     
     
       18. The air-jet texturized and linearly stabilized yarn product obtained by the process of claim 1, said yarn product having a boiling shrinkage of less than 3.3% and an instability of less than 1.0%, measured as the percentage increase in yarn length of a sample having an initial length of one meter under a base load of 1/100 g/den after being subjected to a load of 1/3 g/den for 30 seconds and then relieved again to the base load of 1/100 g/den for another 30 seconds. 
     
     
       19. The yarn product as claimed in claim 18 wherein two or three identically texturized and stabilized yarns are combined into a corresponding three ply yarn with all of the individual yarns having been subjected to an identical shrinking and heat treatment. 
     
     
       20. The yarn product as claimed in claims 18 or 19 wherein each individual yarn is a multifilament polyethylene terephthalate yarn. 
     
     
       21. The yarn product as claimed in claim 18 wound onto said spool after said shrinkage at a predetermined yarn tension and sufficiently stabilized to provide run-off properties permitting the spool to be introduced directly onto a knitting or weaving machine without respooling. 
     
     
       22. The spooled yarn product of claim 21 wherein the yarn is a multifilament polyethylene terephthalate yarn.