Porous film manufacturing method and apparatus

Abstract

A method of manufacturing a porous film includes a decomposition step of introducing a porous film precursor which is formed by coagulating an undiluted film forming solution containing a hydrophilic polymer and a hydrophobic polymer, into a decomposition container; bringing a heated chemical containing an oxidizing agent into contact with the porous film precursor in the decomposition container; warming the porous film precursor in contact with the chemical; and decomposing the hydrophilic polymer remaining inside the porous film precursor using the oxidizing agent. An apparatus for manufacturing a porous film includes a decomposition device provided with the decomposition container.

1 . (canceled) 
     
     
         2 . An apparatus for manufacturing a porous film comprising:
 a decomposition device that decomposes a hydrophilic polymer remaining in a porous film precursor formed by coagulating an undiluted film forming solution containing the hydrophilic polymer and a hydrophobic polymer,   wherein the decomposition device comprises a decomposition container in which a heated chemical containing an oxidizing agent is brought into contact with the porous film precursor, the porous film precursor in contact with the chemical is warmed, and the hydrophilic polymer remaining inside the porous film precursor is decomposed with the oxidizing agent.   
     
     
         3 . The apparatus of  claim 2 , wherein the decomposition device further comprises:
 a heater, which heats an inside of the decomposition container;   a traveling device, which causes the porous film precursor to travel through the decomposition container; and   chemical contacting device, which brings the chemical into contact with the porous film precursor traveling inside the decomposition container.   
     
     
         4 . The apparatus of  claim 3 , wherein the chemical contacting device is provided at a plurality of places inside the decomposition container. 
     
     
         5 . The apparatus of  claim 3 , wherein the heater heats the inside the decomposition container by supplying vapor to the inside the decomposition container. 
     
     
         6 . The apparatus of  claim 3 , wherein the chemical contacting device comprises a chemical vessel into which the chemical is injected and through which the porous film precursor travels through the chemical. 
     
     
         7 . The apparatus of  claim 6 , wherein the chemical vessel is a cascade vessel in which an inside of the vessel is divided into a plurality of zones, and the chemical that overflows from a zone on an upstream side is sequentially supplied to a zone on a downstream side. 
     
     
         8 . The apparatus of  claim 3 , wherein the chemical contacting device comprises a sprayer, which sprays the chemical on the porous film precursor. 
     
     
         9 . The apparatus of  claim 3 , wherein the decomposition container comprises a heat exchange portion inside thereof in which the chemical is heated by heat exchange with a gas inside the decomposition container. 
     
     
         10 . The apparatus of  claim 3 , wherein the traveling device comprises a plurality of traveling rolls and wherein a portion of the traveling rolls are driving rolls. 
     
     
         11 . The apparatus of  claim 3 , wherein the traveling device comprises a plurality of traveling rolls, and wherein a guide bar is attached to at least one of the traveling rolls to prevent the porous film precursor from deviating from the traveling roll. 
     
     
         12 . The apparatus of  claim 3 , wherein the traveling device comprises a plurality of traveling rolls, and wherein a regulation groove is formed on a surface of at least one of the traveling rolls to regulate the traveling of the porous film precursor. 
     
     
         13 . The apparatus of  claim 2 , wherein the decomposition container comprises an entrance through which the porous film precursor is introduced into the decomposition container and an exit through which the porous film precursor is derived out from the decomposition container, and
 wherein at the entrance and the exit, there are respectively provided a water sealing portion that insulates the inside of the decomposition container from outside air and enables the porous film precursor to be introduced and derived.   
     
     
         14 . The apparatus of  claim 13 , wherein the water sealing portion comprises a liquid replacing device that replaces a liquid inside the water sealing portion. 
     
     
         15 . The apparatus of  claim 2 , wherein the decomposition container comprises side wall portions and a top portion which closes upper ends of the side wall portions, and
 wherein the top portion comprises an apex portion and a slope portion which slopes downward from the apex portion.