New technology and application of polyurethane materials and polyurethane products

Polyurethane materials [that is, high molecular polymers containing carbamate groups and -NHCOO in the main chain of macromolecules] have developed rapidly since industrial production was not put on the market in the 1950s. Compared with polymer rubber materials, it has its own unique characteristics. It can be used to produce polyurethane products with different properties and properties by different numbers of functional groups and different types of functional groups and different production processes according to different performance requirements.

Among the rubber types, there are polyurethane rubber varieties that can be crosslinked. There are also those that do not belong to rubber, such as foam plastics, hard plastic products, coatings, high resilience synthetic fibers, artificial leather, adhesives and so on.

Polyurethane materials are widely used in various fields, such as hard products, soft products and bubble products in aerospace industry. They are lighter than metal materials, [very important for aircraft] and have high resilience, non-flammability, high strength, ultra-low temperature insulation and other properties. They are used for aircraft nose covers, speed brake, radomes, aircraft fuel tank fillers, fuel consumption control carburetor buoys, etc., as well as various supporting frames and cushions for interior decoration.

And that product recently developed and use in automobile shock absorption and damping accessories attract people's high attention.

Although there are many kinds of polyurethane products, the classification of their products is nothing more than:

Flexible foam products, hard products, and elastomers [thermoplastic elastomers, vulcanizable elastomers EU, AU].

The molding equipment for its products, such as mixed polyurethane rubber, is generally solid and can be vulcanized with sulfur, peroxide and polyisocyanurate. It can be designed according to the production process and formula of conventional rubber products.

If it is a thermoplastic elastomer, it can be injected or molded. If it is plastic polyurethane, it can be produced by casting process.

Taking flexible polyurethane foam products as an example, the main reaction materials of the formula are polyether, polyester or other polyols; And polyisocyanates. Others include water [chain extender], crosslinking agent, catalyst, foam stabilizer, external foaming agent, flame retardant, mold release agent, colorant and so on. Its production process is generally two-component liquid reaction molding. That is, one group is polyol polymer and isocyanate, and then the above reactants are mixed with another group including water, foaming agent, stabilizer, catalyst and various additives to generate reactants containing organic carbamate, urea group, etc. At the same time, carbon dioxide is generated by the reaction, which releases a lot of heat to vaporize the added foaming agent, and then the foaming speed is adjusted by the catalyst to finally complete the product with uniform foam structure.

At present, the automobile manufacturing industry is constantly improving the safety, comfort and durability, and has high requirements for the durability of shock absorption and damping elastomer accessories under high-strength working conditions. A new type of shock absorber made of polyurethane flexible foam has appeared in foreign markets. Its physical and mechanical properties and shock absorption effect are slightly better than those of rubber shock absorption accessories. The product requires a density of 0. 08g/cm3, the material compression is 5%, the compression strength is above 7Kpa, the product works normally at -20-40 degrees Fahrenheit, the compression set of the product is not more than 10%, and it is oil resistant, and it does not break under repeated pressure impact. There is nothing special about its production process, but the key lies in its main reaction materials. At present, BASF monopolizes the production and supply, and BASF also learns the market supply principle of DuPont for perfluoroether rubber, that is, it only sells finished products, not raw materials, in order to reduce market competitors.

This new type of flexible polyurethane foam automobile shock-absorbing accessory adopts an advanced' one-step' molding process, that is, all raw material components in the formula, such as isocyanate, polyol polymer, chain extender, catalyst, foam stabilizer and other additives, are measured according to the formula, isocyanate is taken as a separate component, and polyol polymer, water, chain extender of auxiliary foaming agent, surfactant, catalyst and other additives are prepared into one component in advance. The foam reaction process is carry out after high-speed stirring and mixing. This one-step production process is especially suitable for processing accessories with complex shapes and small specifications. By means of molding, the mixed composite liquid is directly injected into the mold with complex shape, foamed in the mold cavity and molded. Products made by this method. The specification and size are accurate, and it can also be used as a metal inlay product according to the needs.

Polyurethane products are widely used at present, and the market demand is also great. Although China started late, it has developed rapidly, and its global market share has reached more than a quarter, and it has become the largest manufacturing and consumption market of polyurethane products in the world. Only the shortcomings exist, and the key main reaction materials are still far behind the advanced level abroad, which requires the industry to make efforts to innovate and develop.

It is reported that the wear resistance and environmental protection of retreaded tires with polyurethane as tread rubber are better than those of natural rubber. This innovative research and development has opened up a new way for the new tire turnover technology. During the 13th Five-Year Plan period, the polyurethane industry will have more room for development.