Polyurethane Foam
Polyurethane rigid foam is a high molecular polymer made of isocyanate and polyether as the main raw materials, mixed with a variety of additives such as foaming agent, catalyst, flame retardant, etc. through special equipment, and foamed on-site by high-pressure spraying.
Rigid polyurethane foam plastics are mainly used in building exterior wall insulation, roof waterproofing and insulation integration, cold storage insulation, pipeline insulation materials, building panels, refrigerated trucks and cold storage insulation materials, etc.
Product Type
Polyurethane foam plastics are widely used, almost penetrating into all sectors of the national economy, especially in furniture, bedding, transportation, refrigeration, construction, insulation and other sectors. It has become one of the indispensable materials.
It has become one of the most widely used varieties of plastics. Polyurethane soft foam is mainly used in furniture, bedding and other household items, such as sofas and seats, back cushions, mattresses and pillows; polyurethane rigid foam is mainly used for thermal insulation, refrigeration and freezing equipment and cold storage, insulation panels, wall insulation, pipeline insulation, tank insulation, single-component foam caulking materials, etc.
Uses
A. High efficiency and energy saving, no gaps after filling, strong bonding after curing.
B. Shockproof and pressure-resistant, no cracking, no corrosion, no falling off after curing.
C. With ultra-low temperature thermal conductivity, heat resistance and heat preservation.
D. High efficiency insulation, sound insulation, waterproof and moisture-proof after curing.
E. This caulking agent can adhere to concrete, coating, wall, wood and plastic surfaces.
Polyurethane Foam Waste Recycling
Soft foam recycling technology can be divided into two categories, one is physical method and the other is chemical method. Physical recycling technology is a method of recycling foam plastics by bonding and pressurizing, filling, extrusion molding, etc. This method is simple and easy to implement and relatively mature, but the recycled foam is suitable for low-end products and ages and is eliminated faster. Chemical recycling technology is relatively complex and industrialized later. Until new degradation methods continue to emerge, the foam obtained from the final recycling has better performance.
Physical recycling method
(1) Bonding and pressurizing
This method is to crush the polyurethane soft foam into 3-10 mm pieces through a crusher, put it into a container with a stirrer, spray it with a reactive, single-component moisture-curing polyphenyl polymethylene polyisocyanate adhesive, the amount of adhesive is about 5%-10% of the mass of the waste material, mix it evenly, put the foam sprayed with glue into a mold for molding, and cure it at room temperature for 12 hours according to an appropriate compression ratio, or keep it at 150℃ for 40 minutes to obtain the finished product. The recycled foam can be used as packaging, automobile lining, carpet lining, support and other low-grade parts.
(2) As filler
After screening and cleaning to thoroughly remove the metal impurities that may be contained in the soft polyurethane waste foam, it is crushed into particles with a particle size of about 3 mm, and then the particles are crushed into 180-300 μm powder at low temperature or using a two-roll grinding room temperature crusher, and then the powder is added to the new soft foam composite material as a filler. This not only recycles waste foam plastics, but also reduces the cost of new products. It is economically and technically feasible and is very suitable for soft foam production plants to digest waste within the factory.
(3) Extrusion molding
Extrusion molding uses thermodynamics to convert the molecular chains in soft polyurethane foam into medium-length chains, converting foam materials into soft plastic materials. This material is suitable for making plastic products with high strength and hardness, but low requirements for tensile strength and elongation at break. The specific method is to crush the foam into powder, mix it with thermoplastic polyurethane, granulate it in an extruder, and use injection molding to make products such as soles. Bayer Company of Germany has conducted research in this area. This method is suitable for recycling very limited waste products and is not suitable for large-scale recycling.
Chemical recycling method
(1) Alcoholysis method
In the research on chemical recycling of soft polyurethane waste, alcoholysis is the most active and has achieved good economic and environmental benefits. It is the recycling method currently being promoted. There are many alcoholysis methods that have been studied, among which small molecule alkyl diols are mostly used as the main alcoholysis agent. Under the action of a certain proportion of alcoholysis agent and alcoholysis co-agents such as alcoholamine, tertiary amine, and organic metal compounds, the reaction temperature is controlled at 150-250℃ for alcoholysis reaction for 1-5 hours to obtain a mixture of regenerated polyols and aromatic amines.
(2) Hydrolysis
The hydrolysis method is to introduce water vapor with a pressure of 50-150Kpa into the waste soft foam at a temperature of 250-340℃ under the catalysis of alkali metal hydroxide, and the waste soft foam can be decomposed into amines, polyols, and CO2.
(3) Alkaline hydrolysis method
The alkaline hydrolysis method uses a mixture of one or more alkali metal hydroxides such as NaOH, LiOH, KOH, Ca(OH)2 as a decomposition agent, and a quaternary ammonium salt or sulfate as an activator. The mixture is added to a decomposer containing crushed soft foam and heated to 160°C under stirring to start the decomposition reaction. The mixture is stirred and kept warm for about 4 hours to obtain the alkaline hydrolysis products such as polyols, divalent aromatic amines and sodium carbonate.
Plastic crusher, as an efficient and environmentally friendly mechanical equipment, is gradually becoming a key link in the waste plastic recycling industry chain. It can quickly crush various waste plastic products into small particles, laying the foundation for subsequent recycling and truly achieving the environmental goal of turning waste plastics into recycled raw materials.
For more information on bowling equipment maintenance, please visit and consult with
