Shandong Lanhua Chemical Industry Co., Ltd

Expandable polystyrene (EPS), commonly known as polystyrene and styrene copolymer, is a mixture of resin, physical foaming agent and other additives.
EPS processing technology and process have become more and more perfect and mature in China. However, with the increasingly fierce competition among peers and thinner profits, EPS processing manufacturers have reduced production costs and improved product quality in order to win. This requires EPS processing manufacturers to pay attention to every link in production and processing, analyze and improve the disadvantages in the processing and production process, so as to achieve the purpose.
EPS processing generally goes through the processes of pre foaming, ripening, molding and product ripening
A. Foaming
Raw beads soften when heated to above 92 ℃ by steam in continuous or intermittent pre hair machine, and the volume of volatile particles of foaming agent expands slowly to the required ratio or gram weight. Stable ratio is the guarantee of fixed molding conditions, and the molding quality can be guaranteed. Due to different pre launch conditions, it must rely on the proficiency and experience of operators to properly adjust the pre launch temperature, steam pressure, feed volume and foaming ratio within the allowable foaming speed, so as to obtain satisfactory results.
B. Mellow
Due to the evaporation of foaming agent and the condensation of residual foaming agent, the newly developed foam particles appear soft and inelastic in a vacuum state. Therefore, there must be sufficient time for air to enter the micro pores in the foam particles to make the internal and external pressure balance and elastic. Generally, it takes about 4 hours. In order to improve the quality of products, the time can be extended if conditions permit, The second foaming can be carried out after 2-3 hours of round ripening.
Round ripening should be in the round ripening bin made of mesh anti-static gauze, so as to facilitate the moisture distribution attached to the bubble particles and eliminate the static electricity naturally accumulated during the friction of the bubble particles. At the same time, good ventilation can increase the degree of round ripening.
In order to avoid the fresh foam particles, especially the light foam particles, being crushed by the wind and the cold wind shrinking the foam particles and sharply increasing the ripening time, it is better for the foam particles to fall into the warehouse freely. If conditions permit, the foam particles can be sent by air or sucked into the silo after the foam particles are slightly ripened, so as to obtain full foam particles and reduce the same ripening time.
C. Molding
After ripening, the foam particles are filled in a certain mold and heated by steam to form a molded product with a fixed shape. It has the characteristics of tough, light and dense fusion, closed bubble holes and no water absorption. Improper processing and forming conditions or operation will lead to the shrinkage of finished products, uneven surface, difficult demoulding, brittle products and high scrap rate.
The supply conditions of steam, cooling water and compressed air are the basis to ensure good demoulding, good adhesion, beautiful surface and shorten the forming cycle, so they must be stable.
Main steam pressure: 0.4-0.7mpa
Cooling water pressure: 0.3-0.5mpa
Compressed air: 0.45-0.70mpa
Vacuum degree: - 600-650mmhg
The rich experience of operators is the key to producing good products. They can formulate corresponding operating parameters for a product and adjust corresponding parameters according to the situation of the product, so as to achieve the perfection of the product.
D. Product ripening

The moisture attached to the surface of the demoulded product and the condensation of the product Bubble Particle steam into moisture must be evaporated. At the same time, the product bubble particle is in a vacuum state and has a large shrinkage force due to cold decompression. The products with higher magnification may shrink in the thin-walled part, so they need to be matured. The hardness and strength of the finished products placed in the warehouse or exposed to the sun will be improved, It is better if it can be matured in a drying room of 50-60 ℃.