Polyurethane Recycling In Waste Refrigerator Industry
Polyurethane (PU) is a new polymer material, known as "the fifth largest plastic", and is widely used because of its excellent performance. PU foam products are divided into two major categories : non-foam products and foam products.
Rigid polyurethane foam is an excellent insulation and structural material, its main feature is hard and tough, expandable, flexible, abrasion resistance, low temperature resistance, solvent resistance and other excellent properties of biological aging.
Polyurethane foam is one of the main raw material of refrigerator. In manufacturing process of refrigerators, there will be a lot of scrap plastic, refrigerator market also contains a large number of waste plastic and scrap polyurethane foam. Therefore discarded refrigerator polyurethane recycling has significant environmental and economic value.
Polyurethane physical recycling method
Physical recycling method is changing the physical form of the waste material after the case of the direct use of the basic composition and does not destroy the chemical structure of the polymer itself, does not change the method of. There are burial method, crushing method, gluing and extrusion molding method.
1 Pulverization method
Polyurethane scrap and old scrap was cut or pulverized and sieved to obtain the desired size pieces or fine powder. Generally rigid polyurethane foam pulverized relatively easily, so the technology is more mature smash such as: precision cutting technology, Flachmatritsen extrusion technology. This small piece of waste polyurethane or pulverized powder was mixed into the multi-material recovered for reuse as a filler.
2 adhesive molding
This method is the most common method in the polyurethane recycling. The key points are: firstly crushed polyurethane rigid foam into fine flakes, sprinkle-coated polyurethane adhesive, etc., and then directly put into water vapor and other high-temperature gas, after melting or dissolving, then press cured into a certain shape of the foam.
Another method of bonding process is extrusion, transforming PU material into a soft plastic material, this material is suitable for high strength, high hardness, but the elongation at break of less demanding plastic parts. For waste PU soft foam, it can be ground into a powder, blending the thermoplastic polyurethane, granulated in an extrusion molding machine, using an injection molding method for manufacturing a shoe sole and other products.
Polyurethane chemical recycling method
Chemical recycling process, under conditions of heat and the presence of air, is to achieve recycling of raw materials. The advantage is recyclable insoluble infusible thermoset waste polyurethane.
General process of waste polyurethane chemical recycling: PU waste material sorting, washing, crushed into granules - into reactor - about 200 ℃ plus degradation agent - vacuum distillation and separation and purification - inspection, storage.
Energy Recovery Act
But it should be noted that, if incomplete combustion, it will produce toxic gases during incineration, causing pollution of the atmosphere, so people incineration opposition voices rising.
Due to the excellent performance of rigid polyurethane foam and a wide range of uses, its development is increasing, and therefore its recycling of waste products, not only can effectively protect the environment, reduce pollution, and save resources, turning waste into treasure.
For the use of polyurethane rigid foam waste, from an economic point of view into prenatal, Greenmax recycling machine is good. From the performance of the final product look, or chemical recycling law alcohol solution, alkali and hydrolysis better; at the same time, choose a different approach, with the actual situation, analyze specific issues to get the best input-output ratio.