Porous body and process for manufacturing same

Abstract

The object of the present invention is to provide a porous body having fluid permeance, which contains cellulose-based nanofibers having an extremely thin fiber diameter and high hydrophilicity, and to manufacture a porous body at low cost. The porous body according to the present invention is a porous body in which nanofibers are entangled to form net-like structural bodies in pores of a porous support having many pores that are connecting with one another, wherein the nanofibers are cellulose-based nanofibers, and have a number average fiber diameter of from 1 to 100 nm.

1 . A porous body in which nanofibers are entangled to form net-like structural bodies in pores of a porous support having many pores that are connecting with one another,
 wherein the nanofibers are cellulose-based nanofibers, and have a number average fiber diameter of from 1 to 100 nm.   
     
     
         2 . The porous body according to  claim 1 , wherein the net-like structural bodies have a number average pore diameter of from 10 to 200 nm. 
     
     
         3 . The porous body according to  claim 1 , wherein the support has an average fine pore diameter of from 0.01 to 20 μm. 
     
     
         4 . The porous body according to  claim 1 , wherein the support is either one of a porous film or a fiber sheet. 
     
     
         5 . The porous body according to  claim 1 ,
 wherein the net-like structural bodies contain a surfactant, and   the content of the surfactant is from 0.10 to 100% by mass in terms of solid content concentration with respect to the dry mass of the nanofibers.   
     
     
         6 . The porous body according to  claim 5 , wherein the surfactant is a cationic surfactant. 
     
     
         7 . A process for manufacturing a porous body, including:
 a step of preparing a dispersion liquid, in which a dispersion liquid that cellulose-based nanofibers having a number average fiber diameter of from 1 to 100 nm are dispersed in a dispersion medium is prepared,   a step of attaching, in which the dispersion liquid is attached to a porous support having many pores that are connecting with one another, and   a step of drying, in which the support is dried to remove the dispersion medium.   
     
     
         8 . The process for manufacturing a porous body according to  claim 7 , wherein the dispersion medium is water. 
     
     
         9 . The process for manufacturing a porous body according to  claim 7 , wherein the dispersion liquid contains the nanofibers by from 0.001 to 0.500% by mass in terms of solid content concentration with respect to the total mass of the dispersion liquid. 
     
     
         10 . The process for manufacturing a porous body according to  claim 7 , wherein the dispersion liquid further contains a surfactant, and contains the surfactant by from 0.0001 to 1.0000% by mass in terms of solid content concentration with respect to the total mass of the dispersion liquid. 
     
     
         11 . The porous body according to  claim 3 , wherein the support is either one of a porous film or a fiber sheet. 
     
     
         12 . The porous body according to  claim 2 ,
 wherein the net-like structural bodies contain a surfactant, and   the content of the surfactant is from 0.10 to 100% by mass in terms of solid content concentration with respect to the dry mass of the nanofibers.   
     
     
         13 . The porous body according to  claim 12 , wherein the surfactant is a cationic surfactant. 
     
     
         14 . The porous body according to  claim 1 , wherein the net-like structural bodies contain a surfactant, and the surfactant is a cationic surfactant. 
     
     
         15 . The process for manufacturing a porous body according to  claim 7 , wherein the dispersion liquid contains a surfactant, and the surfactant is a cationic surfactant. 
     
     
         16 . The process for manufacturing a porous body according to  claim 10 , wherein the surfactant is a cationic surfactant. 
     
     
         17 . The process for manufacturing a porous body according to  claim 9 , wherein the dispersion liquid further contains a surfactant, and contains the surfactant by from 0.0001 to 1.0000% by mass in terms of solid content concentration with respect to the total mass of the dispersion liquid. 
     
     
         18 . The process for manufacturing a porous body according to  claim 17 , wherein the surfactant is a cationic surfactant. 
     
     
         19 . The process for manufacturing a porous body according to  claim 7 , further including a step of removing, in which the excessively attached dispersion liquid was removed, and the step of removing is performed after the step of attaching and before the step of drying. 
     
     
         20 . The porous body according to  claim 1 , wherein the raw material of the cellulose-based nanofibers contains at least any one of kraft pulps derived from various wood materials, sulfite pulp, waste paper pulps, mechanical pulps and non-wood pulp. 
     
     
         21 . The process for manufacturing a porous body according to  claim 7 , wherein the raw material of the cellulose-based nanofibers contains at least any one of kraft pulps derived from various wood materials, sulfite pulp, waste paper pulps, mechanical pulps and non-wood pulp. 
     
     
         22 . The porous body according to  claim 1 , wherein the support is inorganic fiber sheets, animal fiber sheets, metal fiber sheets, porous films, porous ceramics, recycled fiber sheets, vinylon sheets or polyvinylidene chloride sheets. 
     
     
         23 . The process for manufacturing a porous body according to  claim 7 , wherein the support is inorganic fiber sheets, animal fiber sheets, metal fiber sheets, porous films, porous ceramics, recycled fiber sheets, vinylon sheets or polyvinylidene chloride sheets.