Expandable copolymer resin used for manufacturing lost foam casting model and preparation method thereof

An expandable copolymer resin used for manufacturing a lost foam casting model, comprising the following components in parts by weight:

• 100 parts of mixed monomers;
• 150-250 parts of deionized water;
• 0.3-0.6 parts of cellulose ether dispersant;
• 0.15-0.45 parts of sodium salt;
• 0.25-0.50 parts of initiator;
• 8-15 parts of foaming agent;
• 0.1-0.5 parts of molecular weight regulator;
• the mixed monomers comprise methyl methacrylate and styrene, the methyl methacrylate accounts for 70-95 wt % of the mixed monomers, and the styrene accounts for 5-30 wt % of the mixed monomers;
• the sodium salt comprises at least one of sodium sulfate, sodium pyrophosphate and sodium dichromate;
• the initiator comprises at least two of tert-butyl peroxyisooctanoate, benzoyl peroxide and tert-butyl peroxybenzoate;
• the foaming agent is consisted of n-pentane, isopentane and petroleum ether in a mass part ratio of 8:(2-6):4;
• the molecular weight regulator comprises at least one of divinylbenzene, ethylene glycol dimethacrylate, C8-C12 alkyl mercaptan, carbon tetrabromide and methyl styrene dimer;
• the molecular weight of the expandable copolymer resin is 150,000 to 300,000.