Devolatilization process for SMA (Styrene Maleic Anhydride) product production

Abstract

The invention discloses a devolatilization process for SMA (Styrene Maleic Anhydride) product production. The devolatilization process comprises mixing, preheating, extruding, filtering and devolatilization treatment of SMA, and relates to the technical field of chemical production. The devolatilization process is characterized in that a preheating mechanism is arranged at the bottom of an extrusion mechanism, and hot oil is used for preheating SMA in a preheating pipe inside a preheating pipe barrel, so that the temperature difference between the SMA and the interior of a machine barrel can be reduced, then the local overheating danger of SMA molecular chains is effectively avoided, and the obtaining rate of the SMA is guaranteed; in addition, a heat conduction pipe is arranged in the machine barrel, the hot oil passing through the preheating pipe barrel enters the heat conduction pipe, and the SMA located in the middle of the machine barrel is heated through the heat conduction pipe; meanwhile, the machine barrel is kept at a certain temperature through an electric heating sleeve arranged on the surface of the machine barrel, and the heating effect of the SMA in the middle of the machine barrel is improved through the heat conduction pipe, so that the problem that monomers are not prone to escaping due to uneven heating of the SMA is solved, and the devolatilization effect on the SMA is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of chemical production, and in particular relates to a devolatilization process for the production of SMA products. Background technique [0002] Styrene-maleic anhydride copolymer (SMA for short), which is obtained by bulk copolymerization of styrene and maleic anhydride. In the reaction process, if the conversion rate of styrene monomer exceeds 90%, a copolymer resin with good transparency and thermal stability cannot be obtained, and when the conversion rate of monomer is less than 40%, more monomers remain in the polymerization system, As a result, the contradiction between dealing with devolatilization and solvent recovery engineering is overburdened. For this reason, the conversion rate of styrene monomer is often controlled to be greater than 60% in industry. Even so, 40% of styrene monomer remains in the system, which must be removed and recovered through devolatilization. [0003] In the existing ...

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Problems solved by technology

In the reaction process, if the conversion rate of styrene monomer exceeds 90%, a copolymer resin with good transparency and thermal stability cannot be obtained, and when the conversion rate of monomer is less than 40%, more monomers remain in the polymerization system, As a result, the contradiction between dealing with devolatilization and solvent recovery engineering is overburdened

[0003] In the existing Chinese patent CN1056623C, a devolatilization process containing styrene-maleic anhydride copolymer is proposed. In this scheme, a twin-shaft screw devolatilization extruder with a combination of multiple exhaust ports and special screw blocks is adopted to adjust The temperature and pressure of each exhaust port match the vacuum degree of the exhaust port with the material temperature of the corresponding port, so that the copolymerization system containing high styrene residual monomer can be separated simply; but SMA is carried out in the extruder During the extrusion process, the heating effect of the SMA in the middle of the extruder is poor, so that the monomer in the SMA in the middle part is not as easy to escape as the outer layer during devolatilization, resulting in a decrease in the devolatilization effect. In addition, when the SMA enters the extruder After leaving the machine, due to the large temperature difference, there is a danger of overheating in the SMA molecular chain, resulting in a decrease in the output of SMA. Therefore, the present invention proposes a devolatilization process for the production of SMA products

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