New-type expandable copolymer resin and preparation method thereof

Abstract

The invention is a preparation method of developable copolymerization resin used to make disappearing-model material, at least composed of mixed monomer, deionized water, dispersant, vesicant, evaocating agent and denaturing aiding agent. Its character: the molecular construction is different, the carbon content of StMMA copolymerization resin (MMA: St=70:30) is 69.6%, and there are two oxygen atoms in StMMA molecule, the oxygen atom escaping in CO gas form. It resolves the problems of carbon fault and carbon adding of EPS model in EPC techinque; StMMA has good separating quality, which makes it possible to use finer pearl particles (0.17-0.20nm) to produce thin-wall cas, and it can make thick-wall and thin-wall cast, the gas of StMMA analyte can quickly escape through the coat and the casting sand can be repeatedly used.

Description

Technical field: [0001] The invention discloses a preparation method of expandable copolymer resin (StMMA for short) used for manufacturing lost foam casting materials, which belongs to the manufacturing field of lost foam casting materials. Background technique: [0002] The lost foam casting (EPC process) used in the casting process is a new process with no allowance and precise molding. Since the easy-to-gasify foam plastic is used as the model, there is no need to take the mold, no parting surface, no mud core, so there is no flash burr, no draft angle, and the size error caused by the combination of core blocks is reduced. Dimensional accuracy and surface roughness approach investment casting. Because lost foam casting adopts dry sand molding, the defects caused by water, binder and other additives in the molding sand are eliminated, and the casting waste rate is significantly reduced. In particular, this new process does not require high technical levels of operators...

AI Technical Summary

Problems solved by technology

However, its shortcomings are: first, the carbon defect problem that occurs when the model is pouring ferrous metal; second, because the EPS molecule contains a thermodynamically stable carbon-rich benzene structure, it is difficult to decompose; third, because the EPS decomposition rate is relatively Slow, it is a disorderly fracture method, and a large amount of liquid is produced. These liquids are in contact with the molten metal for a long time to crack the carbon-oxygen bond in the benzene ring structure, forming hydrogen and carbon, and increasing the carbon by the cavity. opportunity for capture, while containing some sticky residue in the sand, which poses a problem for sand reuse

From the above, the main disadvantage of using the EPS model is that it is easy to cause carbon defects in cast iron and steel castings

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