From the perspective of practical applications, let's talk about the advantages and disadvantages of polyurethane elastomers and the current status and prospects of their application development.
1. The main advantages of polyurethane elastomers
1. The adjustable range of performance is large. Many physical and mechanical performance indicators can be changed within a certain range by selecting raw materials and adjusting the formula, so as to meet the different requirements of users for product performance. For example, hardness is often an important indicator for users of products. Polyurethane elastomers can be made into soft printing rubber rollers with a Shore A hardness of about 20, and can also be made into hard steel rolling rubber rollers with a Shore D hardness of more than 70, which is difficult for general elastomer materials to do. Polyurethane elastomers are flexible polymer materials composed of many flexible segments and rigid segments. With the increase in the proportion of rigid segments and the increase in the density of flexible groups, the original strength and hardness of the elastomer will increase accordingly.
2. Excellent wear resistance. Especially under working conditions with wetting media such as water and oil, its wear resistance is often several to dozens of times that of ordinary rubber materials. Although metal materials such as steel are very hard, they are not necessarily wear-resistant. For example, the metal mouth rings and protective rings of the large water pumps in the Yellow River irrigation area are severely worn and leaking after being washed by a large amount of sediment in just a few hundred hours. However, the mouth rings and protective rings coated with polyurethane elastomers have been running continuously for 1,800 hours without wear. Other applications such as rice husking machine rubber rollers, vibrating screen plates for coal preparation, track races in sports fields, dynamic oil seals for cranes and forklifts, elevator wheels and roller skate wheels are also places where polyurethane elastomers can be used. One point that needs to be mentioned here is that in order to increase the friction coefficient of low and medium hardness polyurethane elastomer parts and improve the wear resistance under load, a small amount of lubricants such as aluminum disulfide, graphite or silicone oil can be added to this type of polyurethane elastomer.
3. Diverse processing methods and wide applicability. Polyurethane elastomers can be molded by plasticizing, mixing, and vulcanization processes like general rubber (MPU); they can also be made into liquid rubber, cast and molded or sprayed, potted, and centrifugally molded (CPU); they can also be made into granules, and molded by injection, extrusion, calendaring, blow molding, and other processes like ordinary plastics (CPU). Molded or injection-molded parts can also be cut, ground, drilled, and other mechanical processes within a certain hardness range. The diversity of processing makes polyurethane elastomers very widely applicable and their application areas are constantly expanding.
4. Oil resistance, ozone resistance, aging resistance, low temperature resistance, good sound permeability, strong adhesion, and excellent biocompatibility and blood compatibility. These advantages are the reason why polyurethane elastomers are widely used in military, aerospace, acoustics, biology and other fields.
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