In the 1930s, the Bayer laboratory in Germany used diisocyanate and polyol polyurethane as raw materials to prepare polyurethane samples such as rigid foam. Since 1946, the United States has carried out research on rigid polyurethane foam, which is used in aircraft sandwich panel parts. In 1952, Bayer reported on the pilot research results of polyester soft polyurethane foam; from 1952 to 1954, it developed a continuous method to produce polyester flexible polyurethane foam technology and developed corresponding production equipment; In 1961, the rigid polyurethane foam was prepared by using polyisocyanate PAPI with lower vapor pressure, which improved the performance of hard products and reduced the toxicity during construction. It was applied to the on-site spraying process to further extend the application range of rigid foam. expand.
Due to the mass production of lower-priced polyether polyols in the 1960s, as well as the development of one-step and continuous soft foam production processes and equipment, polyurethane soft foams have gained application. In the mid-1960s, cold-cured semi-rigid foams and self-skinning molded foams were developed. In the 1970s, cold-cured high-rebound foams were developed on the basis of highly reactive polyether polyols. In the 1970s, Maxfoam flat-top foaming process and vertical foaming process of polyurethane soft foam were developed to make the process of bulk polyurethane soft foam mature. Later, with the development of various new polyether polyols and foam stabilizers, various molded polyurethane foams were also developed.
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