Lyocell fiber, nonwoven fibrous aggregate containing the same, and a mask pack sheet containing the same

Abstract

Disclosed are a lyocell fiber, a nonwoven fibrous aggregate containing the lyocell fiber, and a mask pack sheet containing the nonwoven fibrous aggregate. The lyocell fiber contains a monofilament having a cross-section of a flat yarn or a flat yarn having a curvature. Such lyocell fiber exhibits physical properties that could not be provided by existing lyocell fibers having a circular cross-section, and thus can afford excellent properties such as excellent bendability for industrial material application, good feel and soft gloss property for clothes or interior applications, and transparency, skin adhesion, absorption, and maintenance of a solvent such as moisture, and a smooth surface feel for a mask pack nonwoven fibrous aggregate application.

1 . A lyocell fiber comprising lyocell multifilaments prepared by spinning a lyocell spinning dope comprising a cellulose pulp and a solvent,
 wherein a monofilament making up the multifilament has a cross-section having a central major axis (L1) and a central minor axis (S1), a ratio of lengths of the central major axis (L1) and the central minor axis (S1) is 1.5:1˜10.5:1, and a ratio of a length of a central major axis (L1) and a length of a straight line (L2) between both ends of the central major axis is 1.0-1.5:1.   
     
     
         2 . The lyocell fiber according to  claim 1 , wherein the length of the central major axis (L1) is 12˜42 μm, and the length of the central minor axis (S1) is 4-7 μm. 
     
     
         3 . The lyocell fiber according to  claim 1 , wherein the monofilament has fineness of 1.0-4.0 denier, and a value obtained by dividing a cross-sectional perimeter of the monofilament by fineness is 24.5 to 32 μm/denier. 
     
     
         4 . A nonwoven fibrous aggregate containing lyocell fiber,
 wherein a monofilament making up a lyocell fiber has a cross-section having a central major axis (L1) and a central minor axis (S1), a ratio of lengths of the central major axis (L1) and the central minor axis (S1) is 1.5:1˜10.5:1, and a ratio of a length of the central major axis (L1) and the length of a straight line (L2) between both ends of the central major axis is 1.0-1.5:1.   
     
     
         5 . The nonwoven fibrous aggregate according to  claim 4 , wherein the length of the central major axis (L1) of the monofilament is 12-42 μm, and the length of the central minor axis (S1) is 4-7 μm. 
     
     
         6 . The nonwoven fibrous aggregate according to  claim 4 , wherein the monofilament has fineness of 1.0-4.0 denier, and a value obtained by dividing the cross-sectional perimeter of the monofilament by the fineness is 24.5 to 32 μm/denier. 
     
     
         7 . The nonwoven fibrous aggregate according to  claim 4 , wherein the fineness of the lyocell fiber is 1.0 to 4.0 denier. 
     
     
         8 . The nonwoven fibrous aggregate according to  claim 4 , wherein the fiber length of the lyocell fiber is 36 to 40 mm. 
     
     
         9 . The nonwoven fibrous aggregate according to  claim 4 , wherein a crimp number of the lyocell fiber is 8 to 12 cpi. 
     
     
         10 . The nonwoven fibrous aggregate according to  claim 4 , wherein the lyocell fiber has an emulsion content of 0.1 to 0.4 wt %, based on 100 wt % of the lyocell fiber. 
     
     
         11 . The nonwoven fibrous aggregate according to  claim 4 , wherein a basis weight of the nonwoven fibrous aggregate is 30 to 60 g/m 2 . 
     
     
         12 . The nonwoven fibrous aggregate according to  claim 4 , wherein the thickness of the nonwoven fibrous aggregate is 0.3 to 0.5 mm. 
     
     
         13 . The nonwoven fibrous aggregate according to  claim 4 , wherein the nonwoven fibrous aggregate has moisture absorption of 1000 to 1600%, based on the weight of the lyocell fiber. 
     
     
         14 . The nonwoven fibrous aggregate according to  claim 4 , wherein the nonwoven fibrous aggregate has transparency after moisture treatment of 80 to 84%. 
     
     
         15 . The nonwoven fibrous aggregate according to  claim 4 , wherein the nonwoven fibrous aggregate has transparency after essence treatment of 88 to 94%. 
     
     
         16 . The nonwoven fibrous aggregate according to  claim 4 , wherein the nonwoven fibrous aggregate has skin adhesion after moisture treatment of 3.6 to 4.2 gf. 
     
     
         17 . The nonwoven fibrous aggregate according to  claim 4 , wherein the nonwoven fibrous aggregate has skin adhesion after essence treatment of 4.5 to 5.3 gf. 
     
     
         18 . The nonwoven fibrous aggregate according to  claim 4 , wherein the nonwoven fibrous aggregate has an emulsion content of 0.001 wt % or less, based on 100 wt % of the nonwoven fibrous aggregate. 
     
     
         19 . A mask pack sheet using the nonwoven fibrous aggregate according to  claim 4 .