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

Abstract

The invention discloses an expandable copolymer resin for manufacturing a lost foam casting model and a preparation method thereof and belongs to the field of lost foam casting materials. The expandable copolymer resin has the molecular weight of 150,000-300,000 and is prepared from a mixed monomer, deionized water, a cellulose ether dispersant, a sodium salt, an initiator, a foaming agent and a molecular weight regulator; the mixed monomer is prepared from MMA and ST, the MMA accounts for 70-95% of the weight of the mixed monomer, and the ST accounts for 5-30% of the weight of the mixed monomer; the sodium salt comprises at least one of sodium sulfate, sodium pyrophosphate and sodium dichromate; the foaming agent is prepared from n-pentane, isopentane and petroleum ether; the molecular weight regulator is prepared from at least one of divinylbenzene, ethylene glycol dimethacrylate, C8-C12 alkyl mercaptans, carbon tetrabromide and methyl styrene dimer. The model formed by the expandable copolymer resin has the advantage of reducing or eliminating carbon defects of castings during casting of cast iron and cast steel.

Description

technical field [0001] The invention relates to the field of lost foam casting materials, more specifically, it relates to an expandable copolymer resin for making lost foam casting models and a preparation method thereof. Background technique [0002] Lost foam casting is a new casting technology developed in the 1980s. Its key technology is to replace traditional wooden molds and wax molds with foam plastic molds. Its advantages are as follows: [0003] 1. The dimensional accuracy and surface finish of castings are higher than those of sand castings; [0004] 2. The emission of organic waste gas is less, and it is easy to realize clean production; [0005] 3. The structural design of castings has a great degree of freedom. The components processed and assembled by multiple parts can be molded in pieces and bonded together for integral casting, which greatly saves the cost of assembly and processing. [0006] In order to achieve the above advantages of lost foam casting, ...

AI Technical Summary

Problems solved by technology

[0008] However, the synthetic resin foams used in the prior art are polystyrene, polymethyl methacrylate or their copolymers, and the main component of EPS is benzene ring compounds, which are difficult to thermally decompose at high temperatures, but Under the high temperature of molten iron casting, it is easy to decompose and generate tar-like substances, which adhere to the inner surface of the outer coating of the model. Therefore, a large amount of carbon slag is formed at a high temperature above 900°C and adheres to the surface of cast iron and steel, resulting in carbon in the casting. defect phenomenon

As a result, when casting cast iron and steel, the qualified rate of the final castings is low and the quality is poor

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