Method for manufacturing porous sheet and porous sheet manufactured by the method

Abstract

The present invention provides a method for producing a porous sheet, including the steps of a) producing a polymer resin sheet containing an object to be processed by supercritical fluid extraction which is dissolved in supercritical fluid; and b) injecting the supercritical fluid into the polymer resin sheet to extract the object to be processed by supercritical fluid extraction that is contained in the polymer resin sheet, thereby forming pores in the polymer resin sheet, and a porous sheet produced by the same.

1 . A method for producing a porous sheet, comprising the steps of:
 a) producing a polymer resin sheet containing an object to be processed by supercritical fluid extraction which is dissolved in supercritical fluid; and   b) injecting the supercritical fluid into the polymer resin sheet to extract the object to be processed by supercritical fluid extraction that is contained in the polymer resin sheet, thereby forming pores in the polymer resin sheet.   
     
     
         2 . The method according to  claim 1 , wherein the object to be processed by supercritical fluid extraction contains one or more selected from the group consisting of aromatic compounds, aliphatic hydrocarbons and aliphatic alcohols. 
     
     
         3 . The method according to  claim 1 , wherein the polymer resin sheet of step a) contains a polymer resin selected from the group consisting of polyurethane, thermoplastic elastomer, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastomeric rubber, styrene-based copolymer, polyaromatics, fluoropolymer, polyimide, cross-linked polyurethane, cross-linked polyolefin, polyether, polyester, polyacrylate, elastomeric polyethylene, polytetrafluorethylene, polyethylene terephthalate, polyarylene, polystyrene, polymethylmethacrylate, copolymers thereof, block copolymers thereof, mixtures thereof and blends thereof. 
     
     
         4 . The method according to  claim 1 , wherein step a) includes the steps of a1) mixing the object to be processed by supercritical fluid extraction with a polymer resin or a precursor; and a2) curing the mixture of step a1). 
     
     
         5 . The method according to  claim 4 , wherein in step a1), one or more chain extenders selected from the group consisting of 1,4-butanediol, 4,4′-methylenebis(2-chloroaniline), ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2,4-trimethylpentanediol, hydroquinone, bis (2-hydroxyethyl) hydroquinone, 4,4′-dihydroxybiphenyl, bisphenol A, bisphenol F, and mixtures thereof are further added. 
     
     
         6 . The method according to  claim 4 , wherein in step a2), the curing process is performed at 70 to 100° C. for 4 to 48 hrs. 
     
     
         7 . The method according to  claim 1 , wherein in step a), the object to be processed by supercritical fluid extraction is contained in the polymer resin sheet in an amount of 5 to 50% by weight. 
     
     
         8 . The method according to  claim 1 , wherein the supercritical fluid of step b) contains one or more selected from the consisting of supercritical carbon dioxide, supercritical isobutane, supercritical butane, supercritical propane, supercritical pentane, and supercritical nitrogen. 
     
     
         9 . The method according to  claim 1 , wherein the step b) is performed at a pressure of 50 to 300 atm and a temperature of 25 to 120° C. 
     
     
         10 . The method according to  claim 1 , wherein in step b), the pores formed within the polymer resin sheet have an average diameter of 80 micrometers or less. 
     
     
         11 . The method according to  claim 1 , wherein in step b), the sheet having the pores formed within the polymer resin sheet may have a density of 0.5 to 1 g/cm3. 
     
     
         12 . The method according to  claim 1 , wherein in step b), the polymer resin sheet having the pores has a porosity of 50% or less. 
     
     
         13 . A porous sheet produced by the method according to  claim 1 . 
     
     
         14 . A porous sheet having pores, which is formed by extraction of an object to be processed by supercritical fluid extraction contained in a polymer resin sheet. 
     
     
         15 . The porous sheet according to  claim 14 , wherein the object to be processed by supercritical fluid extraction contains one or more selected from the consisting of aromatic compounds, aliphatic hydrocarbons and aliphatic alcohols. 
     
     
         16 . A polishing pad including the porous sheet according to  claim 13 . 
     
     
         17 . A polishing pad including the porous sheet according to  claim 14 .