Foam molding production process
DATE：2021/11/22 8:38:23 / READ： / SOURCE：This station
Foam molding production process
First mix the unsaturated polyester and styrene monomer at a mixing ratio of (21～2,5)1, then add water, dibenzoyl peroxide and zinc stearate, and then slowly add sodium carbonate and maleic acid Solution and a small amount of dimethylaniline. Sodium carbonate and maleic anhydride react to produce carbon oxide gas. Pour the prepared solution into the mold and keep the temperature at 75°C to obtain a foam with a density of 54kg/m3. If vacuum forming is used and bubbles are introduced, the volume can be expanded by 5 to 8 times.To obtain a foam with a lower density, the mixed system can first flow through a 3.2mm nozzle to the decompression zone and then into the foaming zone. The foaming zone should maintain proper temperature and pressure to promote foaming expansion and solidification. . The foam plastic with a density of 32-64kg/m3 prepared in this way has high strength and good rigidity.
Partially cross-linked polyester resin is foamed in a circular reactor with a free-moving piston. The water generated during the reaction is used to evaporate at 180-220°C. After 15 minutes at 0.08-0.1 MPa, after 0.8 ～1.6kPa completed in 35～60min. If 95 parts of difluorochloromethane and 5 parts of chlorotrifluoromethane foaming agent are used, and chlorinated paraffin and antimony oxide are introduced into the polyester mixed system, foams with flame retardant properties can be prepared. If trifluorochloromethane is used as the blowing agent, medium and high density (12-256kg/m) foam can also be obtained.
In the production process, if 60% alumina is added, the foamed plastic obtained has high hardness, high compressive strength and good fire resistance. Its coking temperature is 1650℃. Adding aluminum powder, sodium silicate powder, dolomite powder and fluorosilicate powder can improve the insulation performance of foam.
Water-filled polyester foam uses unsaturated polyester mixed with water to form a latex solution, which solidifies to form hard white fine granules. This granular material contains very fine water droplets evenly distributed, and the diameter of the water droplets is generally 2 to 5 m. The resin with a moisture content of up to 90% can be used for foaming and expansion, while the optimal strength of the material can still be maintained at 50% to 60%. After dehydration and concentration, the cell wall strength is high enough to withstand the test of the freezing cycle at -34°C. This foamed plastic can be processed by wood processing method for secondary processing.
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