Epoxy foam resin

A process for making epoxy resin foam blocks of varying density comprising the following steps:

• (i) preparing a foam resin comprising:
• a first epoxy resin, a foaming agent to the extent of 2% to 10% of the mass of the epoxy resin, a surfactant to the extent of 2% to 6% of the mass of the epoxy resin, a filler, and a toughening agent, wherein the foam resin is made by the following steps:
• mixing the first epoxy resin and the foaming agent in a reaction chamber and stirring at a speed of about 500 rpm to form a homogeneous mixture;
• heating while stirring the homogeneous mixture to a temperature in the range of about 70° C. to 80° C.;
• increasing the speed of stirring to about 600-1000 rpm and temperature to about 120° C. to 180° C. to obtain a mixture containing froth;
• cooling the mixture containing the froth to a temperature in the range of about 15° C. to 30° C. and skimming off the froth to obtain a reaction resin;
• mixing said reaction resin with the surfactant, the filler and the toughening agent to obtain a mixture containing the reaction resin, the surfactant, the filler and the toughening agent;
• and
• stirring the mixture containing the reaction resin, the surfactant, the filler and the toughening agent at a speed of about 50-200 rpm to form a homogeneous foam resin;
• and
• (ii) preparing a curing agent comprising:
• a hardener and a second epoxy resin, and
• mixing together the foam resin and the curing agent, the ratio of the foam resin to curing agent being in the range of about 100:20 to 100:25 by mass to form a reaction mixture;
• pouring the reaction mixture inside a mold maintained at a temperature in the range of 70° C. to 80° C. and allowing the mixture to cure in the mold for 60 to 100 min.;
• allowing the mold to cool at a temperature in the range of 15° C. to 30° C. and demolding to obtain a green block;
• and
• post-curing the green block in an air circulatory oven for 10 to 15 hrs to obtain a final hard foam block.