Cellulose nonwoven fabric
First Claim
1. A cellulose nonwoven fabric having a porosity of not less than 40% and not more than 99% which comprises not less than 50 wt % of cellulose fibers derived from natural cellulose having a maximum fiber diameter of 1,500 nm or less, a number average fiber diameter of 200 nm or less and a crystallinity determined by solid state NMR techniques of 60% or more wherein the nonwoven fabric has an average transmittance Tr,av of 0.70 or more, which is defined by the following formula (1) and determined by scanning a light with a wavelength of 850 nm perpendicularly to the nonwoven fabric immersed in toluene,(wherein Tr,av is defined by the following formula (1) with a ratio between Tr,1, an average value of transmittances obtained by filling toluene in a test tube in a condition that the nonwoven fabric is stuck to an inside wall thereof, irradiating a light with a wavelength of 850 nm to the test tube in a direction perpendicular to the nonwoven fabric, and scanning each 40-μ
- m length along the test tube in a lengthwise direction thereof to the total length of 30,000 μ
m (number of data;
750), and Tr,2, an average value of transmittances obtained by performing the same measurements except that the nonwoven fabric is removed and only toluene is placed in the test tube)
Tr,av=Tr,1/Tr,2
(1),wherein the dried nonwoven fabric has a sheet non-uniformity parameter H′
of 0.20 or less, which is defined by the following formula (3);
H′
=T′
r,sd/T′
r,av
(3)(wherein T′
r,aV and T′
r,sd, respectively, mean an average value and a standard deviation of all Tr values obtained by irradiating a light with a wavelength of 850 nm perpendicular to a dried sheet surface, and measuring Tr for each 40-μ
m length along the sheet surface in a linear direction thereof to the total length of 30,000 μ
m (number of data;
750)).
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Accused Products
Abstract
Disclosed is a cellulose nonwoven fabric containing cellulose fibers having a maximum fiber diameter of not more than 1500 nm and a crystallinity determined by solid state NMR techniques of not less than 60%. The porosity of the cellulose nonwoven fabric is not less than 40% and not more than 99%.
17 Citations
8 Claims
-
1. A cellulose nonwoven fabric having a porosity of not less than 40% and not more than 99% which comprises not less than 50 wt % of cellulose fibers derived from natural cellulose having a maximum fiber diameter of 1,500 nm or less, a number average fiber diameter of 200 nm or less and a crystallinity determined by solid state NMR techniques of 60% or more wherein the nonwoven fabric has an average transmittance Tr,av of 0.70 or more, which is defined by the following formula (1) and determined by scanning a light with a wavelength of 850 nm perpendicularly to the nonwoven fabric immersed in toluene,
(wherein Tr,av is defined by the following formula (1) with a ratio between Tr,1, an average value of transmittances obtained by filling toluene in a test tube in a condition that the nonwoven fabric is stuck to an inside wall thereof, irradiating a light with a wavelength of 850 nm to the test tube in a direction perpendicular to the nonwoven fabric, and scanning each 40-μ - m length along the test tube in a lengthwise direction thereof to the total length of 30,000 μ
m (number of data;
750), and Tr,2, an average value of transmittances obtained by performing the same measurements except that the nonwoven fabric is removed and only toluene is placed in the test tube)
Tr,av=Tr,1/Tr,2
(1),wherein the dried nonwoven fabric has a sheet non-uniformity parameter H′
of 0.20 or less, which is defined by the following formula (3);
H′
=T′
r,sd/T′
r,av
(3)(wherein T′
r,aV and T′
r,sd, respectively, mean an average value and a standard deviation of all Tr values obtained by irradiating a light with a wavelength of 850 nm perpendicular to a dried sheet surface, and measuring Tr for each 40-μ
m length along the sheet surface in a linear direction thereof to the total length of 30,000 μ
m (number of data;
750)). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- m length along the test tube in a lengthwise direction thereof to the total length of 30,000 μ
Specification