Lyocell filament fibers and tire cord using the same

Abstract

The present invention is relates to lyocell filament fibers having fatigue resistance and durability, of which the dimensional stability at high temperature and the high speed driving performance are good, and a tire cord prepared therefrom.

1 . A lyocell filament fiber, of which the shrinkage behavior factor (SBF) defined by the following Calculation Formula 1 is 0.1 (cN/tex)/% or more at 180° C.:
   Shrinkage behavior factor (SBF)=Shrinkage stress (cN/tex)/Shrinkage rate (%).   Calculation Formula 1
 
 
     
     
         2 . The lyocell filament fiber according to  claim 1 , wherein the shrinkage behavior factor (SBF) is 0.1 to 10 (cN/tex)/%. 
     
     
         3 . The lyocell filament fiber according to  claim 1 , wherein the shrinkage rate of Calculation Formula 1 is 2.0% or less. 
     
     
         4 . The lyocell filament fiber according to  claim 3 , wherein the shrinkage rate is 0.1 to 2.0%. 
     
     
         5 . The lyocell filament fiber according to  claim 1 , which is of multi-filaments, of which the total number of filaments is 200 to 2000 and the total fineness is 200 to 3000 denier. 
     
     
         6 . A lyocell tire cord, wherein the shrinkage rate at 180° C. measured according to ASTM D 5591 is a negative value. 
     
     
         7 . The lyocell tire cord according to  claim 6 , wherein the shrinkage rate is −0.1 to −2%. 
     
     
         8 . The lyocell tire cord according to  claim 6 , wherein the shrinkage stress at 180° C. is 0.01 cN/tex or more. 
     
     
         9 . The lyocell tire cord according to  claim 6 , including a twisted yarn comprising lyocell filament fibers and an adhesive adhered to the twisted yarn, wherein the lyocell filament fibers have shrinkage behavior factor (SBF) of 0.1 (cN/tex)/% or more at 180° C., the SBF being defined by the following Calculation Formula 1:
   Shrinkage behavior factor (SBF)=Shrinkage stress (cN/tex)/Shrinkage rate (%).   Calculation Formula 1
 
 
     
     
         10 . A lyocell tire cord, of which the length deformation rate (LDR) defined by the following Calculation Formula 2 is −1.5% to 1.5%:
   Length deformation rate (LDR)=( L   t   −L   i )/ L   i ×100   Calculation Formula 2
 
 wherein 
 L i  is the initial length of the cord, and 
 L t  is the terminal length measured at 180° C. after loading the initial load of 0.0565 g/d. 
 
     
     
         11 . The lyocell tire cord according to  claim 10 , wherein the length deformation rate is 0 to 1.5%. 
     
     
         12 . The lyocell tire cord according to  claim 10 , wherein the tire cord includes a twisted yarn of lyocell filament fibers. 
     
     
         13 . The lyocell tire cord according to  claim 10 , wherein the tire cord includes a 2 to 3 ply twisted yarn, of which the total number of filaments is 400 to 6000, the total fineness is 400 to 9000 denier, and the twisting level is 200 to 600 TPM. 
     
     
         14 . The lyocell tire cord according to  claim 10 , of which the shrinkage stress at 180° C. is 0 to 0.6 cN/tex. 
     
     
         15 . A lyocell tire cord including a twisted yarn of lyocell filament fibers and an adhesive, of which a flat spot factor defined by the following Calculation Formula 3 is 2.0 or less:
   Flat spot factor (%)=( L   1   −L   2 )/ L   0 ×100   Calculation Formula 3
   wherein   L 0  is the initial length of the cord,   L 1  is the length of the cord measured after loading a load corresponding to 13% of the breaking tenacity of the cord to the cord at a temperature of 120° C. for 5 minutes and cooling the same to 20° C. while maintaining the load, and   L 2  is the length of the cord measured after loading the load corresponding to 13% of the breaking tenacity of the cord to the cord at the temperature of 120° C. for 5 minutes and cooling the same to 20° C. while maintaining the load of 0.01 g/d.   
     
     
         16 . The lyocell tire cord according to  claim 15 , wherein flat spot factor is 0.5 to 2.0%. 
     
     
         17 . The lyocell tire cord according to  claim 15 , wherein the length deformation rate defined by the following Calculation Formula 4 is 5% or less:
   Length deformation rate (%)=( L   1   −L   0 )/ L   0 ×100   Calculation Formula 4
   wherein   L 0  is the initial length of the cord, and   L 1  is the length of the cord measured after loading the load corresponding to 13% of the breaking tenacity of the cord to the cord for 5 minutes at the temperature of 120° C. and cooling the same to 20° C. while maintaining the load.   
     
     
         18 . The lyocell tire cord according to  claim 15 , wherein the total number of filaments is 400 to 6000, the total fineness is 400 to 9000 denier, and the twisting level is 200 to 600 TPM. 
     
     
         19 . A lyocell filament fiber, of which the elongation at yield point defined by the Meredith equation in the stress-strain curve measured at 120° C. is 1.7% or less. 
     
     
         20 . The lyocell filament fiber according to  claim 19 , wherein the elongation in the initial elastic section of the stress-strain curve measured at 120° C. is 0.4% or less. 
     
     
         21 . The lyocell filament fiber according to  claim 19 , wherein the elongation maintaining rate defined by the following Calculation Formula 5 is 95 to 100%:
     S=S   120   /S   105 ×100   Calculation Formula 5
   wherein   S is the elongation maintaining rate,   S 120  is the elongation at yield point measured at 120° C., and   S 105  is the elongation at yield point measured at 105° C.   
     
     
         22 . The lyocell filament fiber according to  claim 19 , wherein the stress at yield point defined by the Meredith equation in the stress-strain curve measured at 120° C. is 4 g/d or more. 
     
     
         23 . The lyocell filament fiber according to  claim 22 , wherein the stress at yield point defined by the Meredith equation in the stress-strain curve measured at 120° C. is 4 to 4.5 g/d. 
     
     
         24 . A tire cord including the lyocell filament fibers according to  claim 19 . 
     
     
         25 . A tire cord of which the elongation at yield point defined by the Meredith equation in the stress-strain curve measured at 120° C. is 3.3% or less. 
     
     
         26 . The tire cord according to  claim 25 , wherein the elongation in the initial elastic section of the stress-strain curve measured at 120° C. is 1.3% or less. 
     
     
         27 . The tire cord according to  claim 25 , of which the elongation maintaining rate (S) defined by the following Calculation Formula 6 is 95 or more:
     S=S   120   /S   105 ×100   Calculation Formula 6
   wherein   S is the elongation maintaining rate,   S 120  is the elongation at yield point measured at 120° C., and   S 105  is the elongation at yield point measured at 105° C.   
     
     
         28 . The tire cord according to  claim 25 , wherein the elongation maintaining rate (S) is 95 to 110%. 
     
     
         29 . The tire cord according to  claim 25 , wherein the stress at yield point defined by the Meredith equation in the stress-strain curve measured at 120° C. is 3.4 g/d or more. 
     
     
         30 . The tire cord according to  claim 29 , wherein the stress at yield point defined by the Meredith equation in the stress-strain curve measured at 120° C., is 3.5 to 4 g/d. 
     
     
         31 . A lyocell filament fiber, of which the ratio Mt/Mi of the terminal modulus Mt to the initial modulus Mi is 0.05 to 0.5. 
     
     
         32 . The lyocell filament fiber according to  claim 31 , wherein the initial modulus Mi is 0.5 to 2.0 (g/d)/%. 
     
     
         33 . The lyocell filament fiber according to  claim 31 , wherein the elongation at maximum point is 5 to 10%. 
     
     
         34 . The lyocell filament fiber according to  claim 31 , wherein the value of Mt and the value of Mi are based on the values measured after conditioning the twisted yarn of filaments having the total number of filaments of 1000, the total fineness of 1650 denier, and the twisting number of 80 TPM at the standard condition (25° C., 65% RH) for 24 hours, and drying the same at 105° C. for 4 hours. 
     
     
         35 . The lyocell filament fiber according to  claim 31 , of which (Mt/Mi) C /(Mt/Mi) D  is 0.5 to 1.0, wherein (Mt/Mi) D  is defined as the value of Mt/Mi of the filament fiber of the dried condition and (Mt/Mi) C  is defined as the value of Mt/Mi of the filament fiber conditioned in the standard condition (25° C., 65% RH). 
     
     
         36 . The lyocell filament fiber according to  claim 35 , wherein the value of (Mt/Mi) C  and the value of (Mt/Mi) D  are based on the values measured by using the twisted yarn having the total number of filaments of 1000, the total fineness of 1650 denier, and the twisting number of 80 TPM. 
     
     
         37 . A tire cord including the lyocell filament fibers according to  claim 31 . 
     
     
         38 . A tire cord including lyocell filament fibers, of which the ratio Mt/Mi of the terminal modulus Mt to the initial modulus Mi is 0.1 to 1.0. 
     
     
         39 . The tire cord according to  claim 38 , wherein the filament fibers are included in the form of 2 to 3 ply twisted yarn, of which the total number of filaments is 400 to 6000, the total fineness is 400 to 9000 denier, and the twisting level is 200 to 600 TPM.