China EPS foam recycling situation and technology progress
In recent years, EPS (expanded polystyrene) foam recycling are attention by relevant departments, regulatory guidance and policy support were introduced. From the whole, made our EPS foam recycling was no small accomplishment. Following several EPS foam recycling technology to achieve the degree of practical methods elaborated.
1. Mechanical recycling.
This method can be divided into simple regeneration and compound recycling in two ways. Simple regeneration is mainly used for the production of the corner waste material also includes easy to clean recycling of disposable waste, their composition is simple and clean, renewable materials separately or mixed in certain proportions using new materials, or you can use existing technology and equipment, are primarily used and proven methods are:
① For recovery and recycling. After crushing, the EPS foam waste, made from PS (polystyrene) foam, hot melt after adding a foaming agent, flame retardant, nucleating agents, processing XPS (extruded polystyrene) foam, the foam is widely used in building materials. At present, the area of the recycling technology in China has been promoting, and became one of the principal avenues for EPS recycling.
② For recycling. Foam manufacturers scrap and non-qualified products through crushing machines can be broken into particles of a certain size, when combined with the new advance Pearl particles, forming again on sheet metal forming machines or package forming machine, made from EPS foam products of various specifications and shapes. Production proven product performance to meet the national standard (GBl0801-2002) under the premise of broken particles between the dosage at 10%~25%, can save raw material 10%~25%.
③ Hot melt regeneration. Hot-melt recycled the following process. A technology of EPS scrap foam is placed at 140 ℃ ~ 190 ℃ constant temperature for baking, making it shrink off bubbles, cool down, crushing, baking generate flammable gas when they needed effective exhaust measures, pay attention to production safety. Another process is to first scrap breaking, again propelling screw foam particle forces joined in the extruder barrel, by the melt extrusion, latiao heating, cooling, cutting into recycled pellets. There is also a process of EPS scrap foam is to be immersed in a high-boiling solvent, making it foam and gel, and then mixed with modified resin, additives, extrusion granulation of the multi-stage exhaust and condensation for solvent recovery. Using gels made from grains, after it has been dried to the solvent content of 6%~l0%, also can be used in the manufacture of polystyrene foam products again.
2. Production of lightweight thermal insulating building materials.
After waste foamed plastics are crushed, by infrared radiation heating, its smaller below one-twentieth; and then mixed with special cement, made from rice flower sugar-like building material, is deemed to be of non-combustible building materials. Such silencers average 60% of building materials, for certain frequency noise suppression of up to 90% per cent. This material is now being used as soundproofing the walls and ceiling of the facility. In addition, EPS foam crushing materials also can be made into light block, external wall insulation mortar and light mortars. Can also glue mixture of clay and EPS foam crushing material according to the certain proportion, baking in the heat, EPS foam crushing material is burning thus made of hollow clay brick, this brick with high strength and excellent thermal insulation properties.
3. Chemical recycling.
Chemical recovery feasibility method as a reconciliation of EPS foam and received national attention, the approach is to break down EPS foam scrap into reusable components such as monomers, compounds, fuel, make EPS foam recycling truly closed-loop process. This method has the following advantages compared with mechanical recycling: generated by the decomposition of chemical raw materials and their quality can be comparable with new materials; in addition, it has the potential of a significant amount of processing waste, is able to realize the real governance of recycling of EPS foam for pollution of the environment.