Code (UR), is formed by the polymerization of polyester or polyether with two different melamine lipid compounds. Its chemical structure of the complex than the general elastic polymer, except for recurring carbamate groups, molecular chain often also contain ester, ether, aromatic radical groups.
Duan Xiangzhong in ur molecular chain by flexible chain segment and rigid chain segment mosaic composition; flexible chain segment, also known as soft chain segment by oligomer Polyols (such as polyester, polyether, polybutadiene); rigid chain segment, also known as hard chain segment, a diisocyanate (TDI, MDI) and small molecule chain extension agent (such as binary amine and diols etc.) of the reaction products. Soft chain segment ratio than the hard segments. Soft and hard chain segment polarity strength of different hard segment polarity is strong, easy to gather together to form many micro District Branch soft chain, said for the micro phase separation structure and its physical and mechanical properties and micro phase separation degree has a great relationship.
Because of the existence of the hydrogen bond, the main chain of UR has high strength and high elasticity.
Features: high hardness, good strength, high elasticity, high wear resistance, tear resistance, aging resistance, ozone resistance, radiation resistance and good electrical conductivity, etc., are generally rubber can not be compared.
classification
Polyurethane elastomer traditional classification is divided according to the processing method and divided into casting polyurethane elastomer, mixed refining type polyurethane elastomer and thermoplastic polyurethane elastic body. Due to the use of raw materials, the synthesis and processing method and application purposes, reaction injection type polyurethane elastic body (RIMPU) and the solution dispersion type polyurethane elastomer. According to formation is divided into solid and liquid systems. There are also divided according to the chemical composition of raw materials, there are generally polyester or polyether, polyether polyurethane elastomers and polyester polyurethane elastomer thereby.
Properties:
(1) excellent wear resistant performance: wear resistance is the highest in all rubber. Laboratory test results show that the wear resistance of UR is 3~5 times of natural rubber, the actual application is often as high as 10 times.
(2) in shore A60 to shore A70 hardness range of high strength, good flexibility.
(3) buffer damping is good. At room temperature, the UR absorption element can absorb the energy of 10%~20% vibration, the higher the frequency, the greater the energy absorption.
(4) resistant to oil and drug resistance good.UR and non polar mineral oil affinity of smaller, in the fuel oil (such as kerosene gasoline) and mechanical oil (such as hydraulic oil, oil, lubricating oil, etc.) almost not affected by erosion, much better than the general rubber can be comparable with the nitrile rubber. The disadvantage is that in alcohols, esters, ketones and aromatic hydrocarbons in the swelling larger.
(5) the friction coefficient is higher, generally above 0.5.
(6) low temperature resistance, ozone resistance, radiation resistance, electrical insulation, good adhesive performance
Curing system:
Isocyanate curing agent, peroxide and sulfur of three kinds: isocyanate curing agent for the common varieties of TDI and two dimers, two MDI dimer and PAPI, can generate allophanate crosslinkages (easy to absorb water, when the attention of environmental humidity), can produce good abrasion resistance, high strength. The hardness of products is bigger; two cumene peroxide (DCP) is the most widely used peroxide curing agent, peroxide curing PUE product has good dynamic performance, small compression permanent deformation, elasticity and aging resistance are good, the disadvantage is not for direct steam vulcanization, tear strength is poor; containing unsaturated chains the PUE adopts the sulfur curing system, the dosage is generally 1.5~2, accelerator M and DM are most commonly used, generally around 6, the comprehensive performance of the vulcanized products better.
Folding edit this paragraph application:
First, it can be applied to the field of plastic runway sports venues, including basketball, volleyball, badminton and tennis courts indoor and outdoor two types. This plastic field than that of the wood floor used for a long time, and abrasion resistant, oil resistant, weather resistant elastic suitable, good shock absorption, through the base of polyurethane rubber has excellent adhesion to be honest. The oil resistance, which is also used as oil resistant roller. Because of the excellent performance, he can replace the alloy in automobile industry, can be used in automobile bumper, steering wheel and vehicle peripheral parts quality. Secondly because with low abrasion, high friction coefficient and low noise etc., so he made a transfer device stable speed. So the coal mine and the mine belt available polyurethane rubber production, casting polyurethane rubber with high hardness can be used for gear gear transmission characteristics of liquid mercury, is stable. In addition, it is also used with lining and Paul Protective layer for nonmetallic antiskid chain for automobile and high-rise buildings save pipe lining; high-pressure seal and high-pressure pipe; in the shoe can reduce costs, beautiful appearance; it can be thin wall aircraft tank, oil resistant seals, dustproof seals; cable street, potting material for electronic components and printed circuit, and can be ideal quakeproof rubber, also in terms of human organs and medical sanitary ware also widely used.
Secondly, it is also used in the national defense industry, such as polyurethane thermal insulation materials in aerospace systems, with excellent adhesion, high strength and so on.
Application examples:
1: for unloading, peeling rubber pad on the die.
2: in punching, bending, shallow drawing and forming process has been widely used.