Development overview of polyurethane foam

Polyurethane foam can be traced back tothe 1940s. During World War II, researchers at Germany's Bayer Laboratory used diisocyanate and polyols as raw materials to produce rigid foams, adhesives and coatings. Polyurethane foam's light weight, easy processing and molding, high specific strength and other properties aroused the interest of American industry, especially those related to the Air Force. In 1946 Later, rigidpolyurethane foam's research work is carried out at Goodyear Aeronautics and Lockheed Aeronautics span>Polyurethane foam (hereinafter referred to as rigid polyurethane foam) is manufactured for use in aircraft sandwich panel components.

In 1952, Bayer reported Softpolyurethane foam (hereinafter referred to as polyurethane soft foam) pilot research results. From 1952 to 1954, Bayer developed a continuous method to produce polyester soft plastic using isocyanate and polyester polyol as raw materials. Polyurethane foam technology and developed corresponding production equipment. Although polyester flexible foam has excellent performance, its cost is high, so people are looking for raw materials that are cheaper than polyester. DuPont in the United States and others will use cheap alkylene oxides, castor oil, etc. as raw materials to prepare polyether polyols for soft materialsPolyurethane foam Products made from this polyether polyol have better performance and lower prices, which has brought another major breakthrough to the polyurethane industry. Polyurethane foam's new products, new processes and new equipment are constantly being developed.

The industrial development of polyurethane soft foam and polyurethane rigid foam began in the late 1950s and 1960s. At the end of 1958, Mobei and Union Carbide in the United States used triethylenediamine with high catalytic activity as a foaming catalyst, and combined it with a silicone surfactant formula to develop a "one-step" process technology. This was a major breakthrough in foam production technology and is still widely used today. With the successful development of one-step foam production technology, the development of soft foam continuous production processes and equipment, and the mass industrial production of lower-priced polyether polyols in the 1960s, polyurethane soft foam first gained application. In the mid-1960s, cold-cured semi-rigid foam and self-skinned molded foam were developed. In 1964, the American Union Carbide Company developed polymer polyols and developed new varieties of soft foam. In the 1970s, high molecular weight and high activity foams were developed. Cold-cured high-resilience foam was developed based on polyether polyols. In the 1970s, the Maxfoam flat-top foaming process and vertical foaming process of polyurethane soft foam were developed based on the continuous horizontal foaming process of the 1960s, making the process of block polyurethane soft foam more mature. Later, various new polyether polyols and foam stabilizers were developed, and various molded polyurethane foams were developed.

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font> Around the 1960s, low-viscosity polyether polyols and low-volatility polyphenyl polymethylene polyisocyanate (PAPI) were developed, and the low gas thermal conductivity foaming agent monochlorotrifluoromethane (CFC) -11), the development of new foam stabilizers and efficient catalysts, as well as the development of efficient foaming machinery, have promoted the development of rigid materials. :19px">Polyurethane foam development and application. The on-site spraying process further expands the application range of rigid foam plastics.

my country's polyurethane foamstarted in the mid-to-late 1950s. Some scientific research units in China, such as the Shanghai Light Industry Research Institute and the Tianjin Textile Research Institute, successively carried out Polyester type and polyether typePolyurethane foam. In 1963, the Jiangsu Provincial Institute of Chemical Industry, the Chemistry Department of Nanjing University and the Nanjing Plastics Factory collaborated To solve key problems, we were the first to successfully develop a one-step polyether polyurethane soft foam production process in China, and in 1966 established a polyether polyol, foam leveling agent (water-soluble silicone "foaming spirit") and domestically produced polyurethane soft foam equipment. Production equipment. In the mid-1960s, Shanghai Plastic Products Factory No. 6, Tianjin Textile Science Research Institute and other units introduced continuous horizontal foaming machines from the UK to produce lumpy soft foam. In the early 1980s, each foam factory successively introduced multiple production line, the production level has been greatly improved. Research on polyurethane rigid foam began in 1964, and it was not produced in a certain scale of small industrial installations until the mid-1970s. It was first used for ships, cold storage, petrochemical pipeline insulation, etc., and later for refrigerators. Freezers have become a major application field for rigid foam. Due to the weak foundation of raw material supporting industry and application development work, development has been slow. In 1978, the national output of polyurethane products, mainly foam plastics, was only about 5,000t. It only began to develop rapidly in the 1980s. stage, especially the rapid development of the national economy in the past 10 years and the entry of large multinational companies into the Chinese market,Polyurethane foamand the entire polyurethane industry have entered a period of rapid development. font> China's polyurethane foam production was estimated to be about 20,000 tons in 1984, about 40,000 tons in 1986, about 91,000 tons in 1988 (about 46,000 tons for soft foam and about 45,000 tons for hard foam), and about 200,000 tons in 1994. About 440,000 tons in 2000 (260,000 tons of soft foam and 180,000 tons of hard foam), about 1.03 million tons in 2004 (550,000 tons of soft foam and 480,000 tons of hard foam), and about 1.48 million tons in 2006 (73 tons of soft foam). million tons, hard foam 750,000 tons), about 1.57 million tons in 2007 (soft foam 755,000 tons, hard foam 814,000 tons).

Foaming After more than 10 years of exploration and practice, the additive Freon replacement technology has gradually matured, and the situation has become clear. In my country, most of the CFC replacements in polyurethane soft foam production are methylene chloride production lines as a transition, and all-water foaming-softening technology. For zero ozone potential (ODP) blowing agent alternative technology, there are production devices using carbon dioxide as the blowing agent. Self-skinning foam uses monofluorodichloroethane (HCFC-141b) and difluorochloromethane (HCFC-22) as the transition route, and the production of self-skinning foam plastics using all-water foaming technology is also popular in China. be applied at the same time. In the production of rigid polyurethane foam, all-water foaming technology is more commonly used in situations where thermal conductivity requirements are not too strict. However, in situations where thermal insulation requirements are high, such as building insulation boards, HCFC-141b is mostly used in China as a transitional foam. alternatives. In the refrigerator industry, HCFC-141b was once used as a blowing agent, but now cyclopentane is mainly used. China announced its ban on CFC-11 on July 1, 2007. In recent years, major companies have begun to develop and launch ideal alternatives to HCFC-141b. Among them, the three most important alternatives in the world with physical properties and foam properties close to HCFC-141b are HFC-245fa, HFC-365mfc and cyclopentane.