With the development of society and the advancement of technology, the application of new materials has become more and more extensive. Since the beginning of the 1980s, polyurethane elastomers have changed from military to military and civilian, and after civilian-oriented, the variety of products has continuously increased. The scale of production is increasing, and the role played by various sectors of the national economy and people ’s clothing, food, housing and transportation is becoming increasingly important. Now from the perspective of practical application, talk about the advantages and disadvantages of polyurethane elastomers and their application and development status and prospects.
First, the main advantages of polyurethane elastomer
1. The adjustable range of performance is large. Many physical and mechanical performance indexes can be changed within a certain range through the selection of raw materials and the adjustment of formulas, so as to meet different requirements of users on product performance. For example, hardness is often an important indicator for users. Polyurethane elastomer can be made into a soft printing rubber roller with a Shore A hardness of about 20, or a hard steel rubber roller with a Shore D hardness of 70 or more. This is difficult to achieve with general elastomer materials. Polyurethane elastomer is a polar polymer material composed of many flexible segments and rigid segments. As the proportion of rigid segments increases and the density of polar groups increases, the original strength and hardness of the elastomer will increase accordingly.
2. Excellent wear resistance. Especially in the working conditions with the presence of water, oil and other wetting media, its wear resistance is often several to tens of times that of ordinary rubber materials. Although metal materials such as iron and steel are very hard, they are not necessarily wear-resistant. For example, the large water pumps in the irrigation area of the Yellow River have a large amount of sediment washed out of the metal ring and protective ring of the overflow parts. , And the ring and protective ring covered with polyurethane elastomer continue to run for 1800 small advances and are still not worn. Others such as rubber rollers for rice milling rice mills, vibrating sieve plates for coal preparation, race track track, dynamic oil seals for crane forklifts, elevator wheels and roller skate wheels, etc. are also polyurethane elastomers Where it comes in. It should be mentioned here that to increase the friction coefficient of medium and low hardness polyurethane elastic components and improve the wear resistance under load, a small amount of aluminum disulfide, graphite or silicone oil can be added to this type of polyurethane elastomer Lubricant.
3. Various processing methods and wide applicability. Polyurethane elastomer can be formed by plasticizing, mixing and vulcanization process (referred to as MPU) like general rubber; it can also be made into liquid rubber, cast molded or sprayed, potted, centrifugal (referred to as CPU); it can also be made Granulated materials, like ordinary plastics, are formed by injection, extrusion, calendering, blow molding and other processes (referred to as CPU). Molded or injection molded parts can also be cut, repaired, drilled, etc. within a certain hardness range. The versatility of processing makes the polyurethane elastomers widely applicable, and the application fields continue to expand.
4. Oil resistance, ozone resistance, aging resistance, radiation resistance, low temperature resistance, good sound permeability, strong adhesion, excellent biocompatibility and blood compatibility. These advantages are the reasons why polyurethane elastomers are widely used in military, aerospace, acoustics, biology and other fields.