Polyurethane applications include soft foam, hard foam, reaction injection molding (RIM) elastomers, cast elastomers, as well as soles, adhesives, coatings, sealants, etc., among which foam accounts for the majority, and soft foam accounts for the majority of foam. Soft foam is mainly used in furniture shockproofing, mattresses, the lower layer of carpets, car seat cushions, shockproof packaging, etc. Rigid foam is mainly used in insulation, as a building insulation laminate, which can be compounded with soft materials such as paper, aluminum foil or hard materials such as aluminum or steel plates; it can also be used in refrigerators, freezers, etc., and for industrial thermal insulation; in addition, it has applications in packaging, transportation, etc. RIM products are mainly used in the automotive industry, including dashboards, bumpers, body panels, standard windows, and are also used in agricultural equipment, mining equipment, equipment housings, and sports goods. Polyurethane castings are mainly used in industrial tires, skate wheels, printer rollers, conveyor belts, pumps, etc. All soft foam waste can be used in the lower layer of rebonded carpets. After separation and purification, the soft foam is cut into pieces of a certain size. The foam pieces are coated with an adhesive. The adhesive is a polyurethane made of toluene diisocyanate (TDI) or diphenylmethane diisocyanate (MDI) and polyether alcohol, and the amount used is 10%-20% of the amount of foam. After adding a catalyst, it is mixed, put into a mold for pressing, and heated and pressurized to cure. Depending on the applied pressure, molded products with different densities (40-100kg/m3) can be obtained. Another way to use foam is to crush the soft foam into a powder of a certain size at low temperature, and then mix the powder with polyols. The amount relative to the polyol can reach 15%-20%; the slurry made of polyols and powders is mixed with isocyanic acid, and then foamed on the foam processing equipment. By controlling the amount of catalyst and isocyanic acid, a foam with good performance can be obtained, which can be comparable to the performance of foam made from the original material.
In addition, polyurethane can be subjected to alcoholysis, hydrolysis, cracking, etc. to recover polyols and related raw materials. It can be processed by steam hydrolysis, glycol hydrolysis, cracking, etc.
