Slivers containing cellulose acetate for spun yarns

Abstract

Sliver containing cellulose acetate staple fibres is obtained that exhibits good fibre to fibre cohesion energy and can be successfully drawn and made into spun yarns. Such slivers can be made of cellulose acetate staple fibres that have of round shape, a denier of less than 3.0, a crimp frequency per inch (CPI) from 5 to 30, a good fibre to fibre coefficient of friction and have a low static charge. The textile fabrics made from spun yarns have plant-based renewable resources by containing the cellulose acetate staple fibres, and can exhibit a thermoplastic behaviour to impart better dimensional stability to a textile fabric. The low denier of the cellulose acetate fibres can impart a feel similar to that of cotton, yet can be successfully processed through carding machines to form cohesive slivers and retain their integrity throughout the drawing process, allowing them to be formed into spun yarns.

1 . A carded sliver comprising cellulose acetate staple fibers (CA staple fibers) having a round shape, a denier of less than 3.0, a crimp frequency per inch (CPI) from 5 to 30, and wherein said sliver either:
 a. has a fiber-to-fiber cohesion energy of at least 10,000 Joules, or   b. is obtained from CA staple fibers having a scroop value of at least 0.2 and not more than 1.   
     
     
         2 . The carded sliver of  claim 1 , wherein said CA staple fibers have an uncrimped fiber to fiber coefficient of dynamic friction (F/F CODF) between 0.11 to less than 0.2 as measured according to ASTM D3412/3412M-13, at one twist, a rate of 20 m/min, and with an input tension of 10 grams on filaments used to make said CA staple fibers. 
     
     
         3 . The carded sliver of  claim 1 , wherein said CA staple fibers have a static electricity charge of less than 1.0 kV at 65% relative humidity as measured using an electrostatic fieldmeter on a two foot sample length of filaments used to make said CA staple fibers rubbed with three times back and forth. 
     
     
         4 . The carded sliver of  claim 1 , wherein the sliver has a coefficient of variation (CVm) of no more than 4.5% or not more than 4%. 
     
     
         5 . The carded sliver of,  claim 1  wherein the sliver has a short fiber content (less than ½ inch) of no more than 15% as determined by the Keisokki Fiber Length Distribution Tester. 
     
     
         6 . The carded sliver of,  claim 1  wherein at least 10 wt. % and up to 55% of the staple fibers in the sliver are CA staple fibers, and wherein the CA staple fibers are coated with a finish. 
     
     
         7 . The carded sliver of,  claim 1  wherein the CA staple fibers have a denier from 0.5 to 1.9, a CPI from 8 to 19, and wherein the cellulose acetate used to make the fibers has an acetyl degree of substitution of at least 2.2. 
     
     
         8 . The carded sliver of  claim 1 , wherein the CA staple fibers have a CPI:DPF ratio from 6:1 to 14:1. 
     
     
         9 . The carded sliver of any one of  claim 1 , wherein at least 90% of the CA staple fibers have a shape factor from 1.0 to 1.5. 
     
     
         10 . The carded sliver of  claim 1 , wherein at least 90 wt. % of the CA staple fibers have a cut length of 10 mm to 150 mm. 
     
     
         11 . The carded sliver of  claim 1 , wherein said CA staple fibers are coated with a finish in an amount of less than 2.0 wt. % FOY on a dry weight basis. 
     
     
         12 . The carded sliver of  claim 1 , wherein said CA staple fibers have a tenacity of at least 0.9 grams-force/denier, as measured according to ASTM D3822, or are made from filaments that have a tenacity of at least 0.9 grams-force/denier, as measured according to ASTM D3822. 
     
     
         13 . The carded sliver of  claim 1 , wherein said CA staple fibers have an elongation at break of at least 15%, as measured according to ASTM D3822, or wherein the sliver is obtained from staple fibers made from filaments that have an elongation at break of at least 15%, as measured according to ASTM D3822. 
     
     
         14 . The carded sliver of  claim 1  having a fiber-to-fiber cohesion energy of at least 15,000 Joules or at least 20,000 Joules. 
     
     
         15 . A spun yarn obtained from one or more carded slivers that are drawn, and at least one of said carded staple slivers comprising cellulose acetate staple fibers (CA staple fibers) having a round shape, a denier of less than 3.0, a crimp frequency per inch (CPI) from 5 to 30 wherein said at least one sliver either:
 a. has a fiber-to-fiber cohesion energy of at least 10,000 Joules, or   b. is obtained from CA staple fibers having a scroop value of at least 0.2 and not more than 1.   
     
     
         16 . The spun yarn of  claim 15 , wherein said CA staple fibers have an uncrimped fiber to fiber coefficient of dynamic friction (F/F CODF) between 0.11 to less than 0.2 as measured by according to ASTM D3412/3412M-13, at one twist, a rate of 20 m/min, and with an input tension of 10 grams on filaments used to make said CA staple fibers, and have a have a static electricity charge of less than 1.0 kV at 65% % relative humidity as measured on a two foot sample length of filaments used to make said CA staple fibers rubbed with three times back and forth. 
     
     
         17 . The spun yarn of  claim 1 , wherein said yarn contains from 10 wt. % to 70 wt % CA staple fibers. 
     
     
         18 . The spun yarn of  claim 15 , wherein said yarn has at least one of the following characteristics: (i) a breaking force of at least 150 g-N, as measured according to ASTM D2256 on a sample containing 100% of the CA staple fibers, (ii) a tenacity of at least 0.85 gF/denier as measured according to ASTM D2256 on a sample containing 100% of the CA staple fibers, or (iii) an elongation at break of at least 13% as measured according to ASTM D2256 on a sample containing 100% of the CA staple fibers. 
     
     
         19 . The spun yarn of  claim 1 , having a total denier of less than 300 and a twist per inch of less than 4. 
     
     
         20 . A textile fabric obtained from spun yarn, said yarn obtained from carded slivers comprising CA staple fibers (CA staple fibers) containing a quantity of spin finish, and wherein the textile fabric contains no spin finish or a quantity of spin finish that is less than said quantity on the CA staple fibers, said staple CA staple fibers having round shape, a denier of less than 3.0, a crimp frequency per inch (CPI) from 5 to 30, wherein said one or more carded slivers either:
 a. has a fiber-to-fiber cohesion energy of at least 10,000 Joules, or   b. is obtained from CA staple fibers having a scroop value of at least 0.2 and not more than 1.   
     
     
         21 .- 42 . (canceled)