Polyurethane elastomer is a high polymer between plastic and rubber in terms of its modulus, mainly including polyurethane compound rubber, polyurethane casting rubber, polyurethane water latex and polyurethane thermoplastic. Polyurethane leather (PU leather), polyurethane adhesive, polyurethane coating, polyurethane elastic fiber and polyurethane foam rubber are all specific application parts derived from the above four types of rubber. The polyurethane elastomer is divided into twelve aspects to be described below.
(1) The kneading type polyurethane elastomer is made into various products by the same processing method as natural rubber. Vulcanization is a vulcanization molding process in which cross-linking is carried out through chemical bonds. The vulcanizing agent can be peroxide (such as DCP), sulfur and polyisocyanate, or a vulcanizing agent used in combination with peroxide and polyisocyanate. Fillers can be added to reduce costs, reinforcing agents can be added to improve mechanical properties, and various additives can be added to improve certain properties.
(2) Pouring and acid casting molding of cast-type polyurethane shade elastomer can be poured into various complex chess-shaped products. It can be used as a polyurethane coating with a solvent, and it can be painted into a spray coating: the fabric can be impregnated with a solvent, and then processed into artificial suede; it can also be sprayed on the cloth with a solvent to make artificial fur, etc. These products can be used as paving materials, stadium floor paints, stadium running tracks, waterproofing materials for construction, interior and exterior decorative paints for furniture and walls, etc. Polyurethane casting rubber can be made into various crystals by adding appropriate catalysts by room temperature vulcanization, and can be processed into elastic foam rubber by adding foaming agent.
(3) Polyurethane water latex Polyurethane water latex is the structural group of polyurethane elastomer, which is hydrophilic and hydrophobic; that is, some groups can be dissolved in water and some groups can only be dissolved in solvents. Polyurethane water latex can be used as coatings and adhesives, decoration materials and paving materials. Impregnated fabrics can be used as reinforcing materials; can make a variety of high-strength laminates. It can be used as finishing agent and fabric finishing agent, and the performance of cross-linked water latex has caught up with the performance of solvent-based polyurethane.
(4) Thermoplastic polyurethane elastomers can be made into various elastic products by processing methods like plastics, which can be processed by compression molding, injection molding, extrusion, jade extension and blow molding. With solvent, it can be used to make coatings, and it can also make PU leather, which can be used in clothing, packaging materials and shoe upper leather. Various fillers and additives can be added during processing to reduce costs and improve certain physical properties, and colorants can also be added to make the products have various bright colors.
(5) Polyurethane leather Polyurethane leather is generally called PU leather. PU leather is made of polyurethane casting glue, thermoplastic and polyurethane water latex. Polyurethane casting glue is used as the adhesive layer or foam layer of PU leather, and polyurethane water latex and polyurethane thermoplastic are used as the surface layer of PU leather. In the production process, it is divided into wet production process and dry production process
Process: In terms of the structure of leather, it is divided into adhesive and non-adhesive, foamed layer and non-foamed layer; in application, it is divided into garment leather, shoe upper leather and industrial leather.
(6) Polyurethane elastic fiber Polyurethane elastic fiber is a fiber made by drawing and spinning with all-thermoplastic polyurethane thermoplastic. These elastic fibers are used for urban fabrics, socks, etc. for people to wear, and coloring materials can be used to make beautiful, durable and brightly colored clothing.
(7) Polyurethane coating Polyurethane coating is also called polyurethane paint or polyurethane enamel. Homogeneous polyurethane coating can be made by adding solvent from polyurethane thermoplastic or casting glue. The polyurethane latex is a heterogeneous polyurethane coating. Polyurethane coatings are further divided into two-component polyurethane coatings and one-component polyurethane coatings. Polyurethane coatings are oil-resistant, wear-resistant, weather-resistant, have firm adhesion, smooth surface and small friction coefficient. This kind of coating is applied on the surface of modern transportation vehicles, with low frictional resistance and energy saving. Therefore, polyurethane coatings are used in foreign aircraft, automobiles and ships.
(8) There are many types of polyurethane adhesives, polyisocyanate adhesives, polyurethane prepolymer adhesives, one-component polyurethane adhesives, two-component polyurethane adhesives, polyurethane thermoplastics Adhesives, polyurethane hot melt adhesives, polyurethane self-adhesives, polyurethane pure adhesives, powdered polyurethane adhesives, film polyurethane adhesives, strips, tapes, polyurethane rollers and bonded polyethylene, Polyurethane adhesives for polypropylene, etc.
Polyurethane adhesive has good bonding effect on various fabrics, plastics, rubber, wood, glass and pottery products and cement products, and its peel strength is 300-500N/cm (under hot pressing). The urethane adhesive is bonded to steel, aluminum, copper and other gold screens, and its peel strength can reach 300-1000N/cm (in the case of hot pressing).
(9) Polyurethane foam rubber Polyurethane foam rubber is made by mixing polyurethane compound rubber, thermoplastic plastic and casting rubber with foaming agent.
This kind of rubber is particularly elastic, comfortable to lay and sit on, and will not feel very tired for a long time, so it is widely used in bicycle seats, driver seats and sofas of motorcycles, cars, airplanes, ships, and passenger seats.
(10) Polyurethane auxiliary materials are synthesized by one-step method, prepolymerization method and semi-prepolymerization method. Polyurethane casting adhesives with different properties are added with different pigments and different fillers, and are paved on the ground of sports fields and hotels, or used for waterproofing. The material is auxiliary installed on the roof, and used as a caulking material in construction projects and transportation vehicles such as automobiles and trains. In the construction, it can be divided into one-component and two-component for construction.
(11) Polyurethane grouting material Polyurethane prepolymer is added with different fillers and injected into the formation to stabilize the ground, prevent seepage, prevent leakage, and block water. It is divided into oil-soluble and water-soluble polyurethane grouting materials.
(12) Medical polyurethane materials.
