Summary
code (UR), by polymerization of a polyester (or polyether) and diisocyanate compounds formed by dicyandiamide lipid. Its chemical structure is generally more complex than the elastomeric polymer, in addition to recurring urethane groups, often also containing molecular chain an ester group, an ether group, an aromatic group and the like groups.
UR molecular main chain by a flexible segment and a hard segment composed of mosaic; also known as the soft segment soft segment, a polyol oligomer (e.g., polyesters, polyethers, polybutadiene ) configuration; hard segment known as the hard segment, the reaction product of a diisocyanate (e.g., TDI, MDI, etc.) and small molecule chain extender (diol, such as diamines and the like) configuration. The proportion of soft segment than the hard segment. Soft, the strength of different polarities of the hard segment, the hard segment polar, together readily, to form a plurality of micro branches soft segment phase, called micro-phase separation structure, its physical and mechanical properties of the micro phase there are a lot degree of separation.
between UR molecular main chain by the biasing force due to hydrogen bonding, and thus has high strength and high elasticity.
properties: high hardness, high strength, high elasticity, high wear resistance, tear resistance, aging resistance, ozone resistance, radiation and good electrical conductivity, etc., is generally not more than rubber of.
Category
traditional classification is based polyurethane elastomer to the division processing method, into casting polyurethane elastomer, polyurethane elastomer and kneading thermoplastic polyurethane elastomer . As the raw material used, synthesis and processing purposes, such as different applications and methods, there was a reaction injection polyurethane elastomer (RIMPU) and dispersion solution of polyurethane elastomer. According to the shape formed by the system is divided into solid and liquid systems. There is also the raw material chemical composition points, generally do not have the polyether or polyester type, hence the polyether polyurethane elastomers and polyester-based polyurethane elastomer.
properties:
(1) Wear Resistance Excellent: All the wear of rubber is the highest. Results showed that laboratory, UR wear resistance is 3 to 5 times natural rubber, practical applications are often as high as 10 times.
(2) Shore A60 to A70 Shore hardness within a range of the high strength, good elasticity.
(3) good shock absorption. At room temperature, UR damping element can absorb 10% to 20% of the energy of vibration, the higher the vibration frequency, the greater the energy absorption.
(4) good chemical resistance and oil resistance. UR affinity for non-polar mineral oil is small, almost no erosion of the fuel (e.g., kerosene, gasoline), and machine oil (e.g., hydraulic oil, oil, lubricants, etc.), much better than the general purpose rubber, comparable with nitrile rubber. The disadvantage is swellable in alcohols, esters, ketones and aromatic hydrocarbon is large.
(5) a high coefficient of friction, generally above 0.5.
(6) temperature resistance, ozone, radiation, electrical insulation and good adhesion properties.
curing system:
isocyanate curing agent, a peroxide and sulfur categories: Common varieties isocyanate-based curing agent and a dimer of TDI, and the MDI dimer PAPI the like, may be generated allophanate bond crosslinks (easy to absorb water when ambient humidity Note that use), can be prepared good abrasion resistance, high strength, greater stiffness article; dicumyl peroxide (DCP ) is the most common use of a peroxide vulcanizing agent, a peroxide curing PUE product having good dynamic properties, low compression set, flexibility, and aging resistance are good, the disadvantage is not directly vulcanizing steam, tear strength poor; PUE segment containing an unsaturated sulfur curing system employed, is generally used in an amount of 1.5 to 2 parts accelerator M and DM most commonly used, usually about 6 parts, preferably vulcanized article overall performance.
Applications:
First, it can be applied to plastic track track and field sports venues, including basketball, volleyball, badminton and tennis courts indoor and outdoor types. Longer than the plastic flooring site use, and abrasion resistance, oil, weathering suitably elastic, shock-absorbing properties, the base layer through the adhesive honest. Urethane rubber has excellent oil resistance, and thus also as oil Kun tube. Because of excellent performance, in the automotive industry can place his alloys, can be used in automotive bumper, automotive steering wheel and upper peripheral parts. Second, because of having a low wear, noise and high coefficient of friction, etc., so that the transfer device he produced a steady speed. Coal mine and mix it with a belt that can be made of polyurethane, a polyurethane rubber of high hardness can be used for pouring mercury gear gear transfer liquid having stable characteristics. It also with the backing and a protective layer made of non-metallic high-rise buildings and automobile anti-skid chains save pipe liner; for high pressure seal and a high pressure hose; shoe can be reduced in terms of cost, nice; it can be used as a thin plane wall tank, oil seals, dust seals; streets for the cable, electronic components and printed circuits potting material, and vibration-proof rubber may be desirable, while in human organs and medical instrument also has a wide range of uses.
Next is also used in the defense industry, aerospace systems, such as polyurethane insulating material having excellent adhesion property, high strength and so on.
Application examples:
1: on the die for unloading, peeling rubber.
2: has been widely used in punching, bending, shallow drawing and molding step.