Biodegradable Nonwoven Fabric

Abstract

The present disclosure provides: a biodegradable nonwoven fabric for thermoforming, the biodegradable nonwoven fabric being composed of a fiber of a polylactic acid-based polymer, and having a basis weight of 20-300 g/m 2 , preferably, a biodegradable nonwoven fabric characterized by being composed of a long fiber of a polylactic acid polymer, having an MD-direction elongation of 50% or more at 120° C., and having an MD-direction dimensional change rate of ±4% or less at 80-140° C. as determined by thermomechanical analysis; a method for producing a molded body by using said biodegradable nonwoven fabric; and a method for molding a biodegradable beverage extraction container, the method being characterized in that the molded body has an MD-direction elongation change rate of 4% or less, as determined by thermomechanical analysis (TMA) under a load of 0.05 N/2 mm at 30-100° C.

1 . A biodegradable nonwoven fabric for thermoforming comprising fibers of a polylactic acid-based polymer, wherein the basis weight of the biodegradable nonwoven fabric is 20 g/m 2  to 350 g/m 2 . 
     
     
         2 . The biodegradable nonwoven fabric according to  claim 1 , wherein elongation in the MD direction at 120° C. is 50% or more, and dimensional change rate in the MD direction at 80° C. to 140° C. as measured by thermomechanical analysis is ±4% or less. 
     
     
         3 . The biodegradable long-fiber nonwoven fabric according to  claim 1 , wherein, in a temperature dependency test for evaluating dynamic viscoelasticity, the storage modulus over a temperature range of 90° C. to 150° C. is 10 MPa to 500 MPa. 
     
     
         4 . The biodegradable nonwoven fabric according to  claim 1 , wherein the value obtained by dividing the longitudinal tear strength of the nonwoven fabric by the basis weight thereof is 0.002 N/(g/m 2 ) to 0.5 N/(g/m 2 ). 
     
     
         5 . The biodegradable nonwoven fabric according to  claim 1 , wherein the birefringence of the fibers in the nonwoven fabric is 0.002 to 0.10. 
     
     
         6 . The biodegradable nonwoven fabric according to  claim 1 , wherein the fibers in the nonwoven fabric further comprise, in addition to the polylactic acid-based polymer, 0.5 wt % to 30 wt % of an aliphatic ester copolymer based on total resin weight. 
     
     
         7 . The biodegradable long-fiber nonwoven fabric according to  claim 1 , wherein the average fiber diameter of the nonwoven fabric is 1 μm to 40 μm and the nonwoven fabric is composed of long fibers. 
     
     
         8 . The biodegradable nonwoven fabric according to  claim 1 , wherein, in a temperature dependency test for evaluating dynamic viscoelasticity, the maximum value of the loss tangent (tan δ) of the nonwoven fabric is 0.5 or less. 
     
     
         9 . The biodegradable nonwoven fabric according to  claim 1 , wherein, in a temperature dependency test for evaluating dynamic viscoelasticity, storage modulus of the nonwoven fabric at 10° C. to 70° C. is 200 MPa or more. 
     
     
         10 . The biodegradable nonwoven fabric according to  claim 1 , wherein the R/Ave value of the basis weight of a 2.5 cm square of a stretched sheet of the nonwoven fabric, which has been biaxially stretched in the MD/CD directions simultaneously at an area magnification of 6.25 times at a temperature of 120° C., is within 1.0. 
     
     
         11 .- 13  (canceled) 
     
     
         14 . A molded body comprised of the biodegradable nonwoven fabric according to  claim 1 , wherein the molding index of the molded body is 1.1 or more. 
     
     
         15 . A molded body group comprised of the biodegradable nonwoven fabric according to  claim 1 , wherein the molding index thereof is 1.1-fold to 20-fold, and the R/Ave values of the basis weights of pieces of fabric sampled from the same location on the bottoms of 10 or more molded bodies molded with the same molding machine from a continuous nonwoven fabric are within 0.5. 
     
     
         16 . A biodegradable beverage extraction container comprised of the molded body according to  claim 14 , wherein the elongation change rate in the MD direction, as measured by thermomechanical analysis (TMA) at 30° C. to 100° C. when a load of 0.05 N/2 mm is applied to a molded body piece constituting the container, is 4% or less. 
     
     
         17 . The beverage extraction container according to  claim 16 , wherein a change in capacity of the container during immersion in boiling water is 20% to 90%. 
     
     
         18 . The beverage extraction container according to  claim 16 , wherein the degree of orientation of a nonwoven fabric molded body constituting the beverage extraction container is 0.010 or more. 
     
     
         19 . The beverage extraction container according to  claim 16 , wherein the degree of crystallinity of a nonwoven fabric molded body constituting the beverage extraction container is 30% to 70%.