Styrofoam foaming method
DATE：2022/1/11 8:47:53 / READ： / SOURCE：This station
Styrofoam foaming method
Foams made of dissolved liquids as foaming agents can be divided into two types in terms of production methods.
① Add low-boiling point liquid into suspension polymerized styrene particles to form expandable beads, and then make products through pre-foaming, curing and foam molding. This method is called expandable beads Foaming method.
② The mixture of high molecular weight polystyrene resin, foaming agent and other agents is extruded and foamed through the extruder head, and then cooled and shaped into foam products. This method is called direct extrusion foaming method. , Expandable bead foaming method.
The manufacture of expandable polystyrene beads, the manufacturing methods of expandable polystyrene beads include one-step, one-half and two-step methods
In the one-step method, styrene, an initiator and a blowing agent are added to the reaction together at the beginning, and the pellets obtained by polymerization already contain the blowing agent, and become expandable polystyrene beads. The expandable polystyrene beads made by the one-step method have uniform and small cells, and the product has good elasticity. The foaming agent is added during the polymerization, which can save the operation process, but the foaming agent is used as a stone to inhibit polymerization. The relative molecular weight of the polymer is low, and there is some powder after the reaction, which needs to be processed
(2) One-step and a half method When the monomer styrene is polymerized to form elastic beads, four foaming agents are added and the polymerization is continued until the end. The polystyrene beads thus obtained also contain a foaming agent. The advantages and disadvantages of the one-step and half-method are roughly the same as the one-step method, because the foaming agent is added in the middle stage of reaction anti-oxidation, the polymerization inhibition effect has been reduced, the operation cycle has been shortened, and the relative molecular mass of the polymer is improved than the one-step method.
③Two-step method The first step is to polymerize styrene into polystyrene beads, the second step is low boiling and then the polystyrene beads are screened into different grades, and then a fat substitute foaming agent is added to the beads of the same grade. , heating to make the foaming agent penetrate into the beads, and after cooling, it becomes expandable polystyrene beads. The two-step method has many operating procedures, and the penetration time of the foaming agent is longer, but the quality of the polymer is improved, and the relative molecular weight can reach 55000600. In addition, the particle size is screened, and the unqualified ones are removed in advance, which helps to improve the quality of the products, so the two-step method is mostly used. The two-step method is now used as an example to illustrate the production process.
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