Method for producing molding sand, and molding sand

Abstract

A method for producing molding sand includes mixing an artificial sand with a furan resin composition including a furan resin precursor, and mixing a curing agent with the artificial sand with which the furan resin composition is mixed, wherein the curing agent includes xylene sulfonic acid.

1 . A method for producing a molding sand, the method comprising the steps of:
 mixing artificial sand with a furan resin composition including a furan resin precursor, and   mixing a curing agent with the artificial sand with which the furan resin composition is mixed,   wherein the curing agent includes xylene sulfonic acid.   
     
     
         2 . The method for producing a molding sand according to  claim 1 , wherein
 in the step of mixing the artificial sand with the furan resin composition, the temperature is 100° C. or less.   
     
     
         3 . The method for producing a molding sand according to  claim 1 , wherein
 0.3 parts by mass or more and 3 parts by mass or less of xylene sulfonic acid is mixed relative to 1 part by mass of the furan resin precursor.   
     
     
         4 . A molding sand comprising:
 an artificial sand,   a surface-modified layer containing furan resin covering the artificial sand, and   a curing agent layer attached to the surface-modified layer, wherein   the curing agent layer includes xylene sulfonic acid.