Introduction to PU polyurethane rubber

Polyurethane rubber has excellent abrasion resistance and Good airtightness, the operating temperature range is generallyis -20~80℃. In addition, it also has moderate resistance to oil, oxygen and ozone aging, but is not resistant to acids, alkalis, water, steam and ketones. Suitable for manufacturing various rubber sealing products, such as oil seals, O-rings and diaphragms.

Polyurethane rubber is a series of elastomer materials that contain more urethane groups on the polymer backbone. It is actually polyurethane rubber, referred to as polyurethane rubber or urethane rubber.(urethane rubber) or polyurethane elastomer (polyurethane elastomer). In addition to urethane groups, the polymer chain also contains ester groups, ether groups, urea groups, aryl groups and aliphatic chains. It is usually formed by the reaction of oligomer polyol, polyisocyanate and chain extender. Polyurethane rubber forms different structures and types depending on the raw materials and proportions used, reaction methods and conditions, etc.

1. PU polyurethane rubber properties:

1. Resistance to low temperature and resistance to It has good ozone, radiation resistance, electrical insulation and bonding properties.

2. Oil resistance and drug resistance Good sex. UR has less affinity with non-polar mineral oil and is almost not corroded in fuel oil (such as kerosene, gasoline) and mechanical oil (such as hydraulic oil, engine oil, lubricating oil, etc.), which is much better than general-purpose rubber. Comparable to nitrile rubber. The disadvantage is that it swells greatly in alcohols, esters, ketones and aromatic hydrocarbons.

3. Excellent wear resistance: The grinding performance is the highest among all rubbers. Laboratory measurement results show that the wear resistance of UR is 3 to 5 times that of natural rubber, and is often as high as about 10 times in practical applications.

4. Good buffering and shock absorption. At room temperature, UR shock-absorbing elements can absorb 10% to 20% of vibration energy. The higher the vibration frequency, the greater the energy absorption.

5. From Shaw A60 to Shaw It has high strength and good elasticity in the hardness range of A70.

6. The friction coefficient is high, generally above 0.5.

2. PU polyurethane rubber application:

First of all, it can be applied to plastic track sports venues in track and field, including basketball, volleyball, badminton and tennis venues. Both indoor and outdoor types. This kind of plastic floor lasts longer than wooden floors, is wear-resistant, oil-resistant, weather-aging resistant, has suitable elasticity, good shock-absorbing performance, and is firmly bonded to the base layer. Polyurethane rubber has excellent oil resistance and is therefore also used as an oil-resistant cylinder. Due to its excellent performance, it can replace other alloys in the automobile industry and can be used in automobile bumpers, steering wheels, and automobile peripheral components. Secondly, due to the advantages of low wear, high friction coefficient and low noise, the transmission device made of it has stable rotation speed. Therefore, conveyor belts used in coal mines and mines can be made of polyurethane compound rubber, and high-hardness polyurethane casting rubber can be used as gear mercury gears, which have the characteristics of stable liquid transmission. In addition, it is also used as lining and protective layer, as non-metal car anti-skid chains and as lining of high-rise building firefighting water pipes; as high-pressure seals and high-pressure water pipes; in shoemaking It can reduce costs and be beautiful; it can be used as aircraft thin-walled fuel tanks, oil-resistant seals, dust-proof seals; as potting materials for cable streets, electronic components and printed circuits; and it can be used as an ideal shock-proof rubber, and it can also be used in human organs. It is also widely used in medical and sanitary equipment.

Secondly, it is also used in the defense industry, such as polyurethane insulation materials in aerospace systems, which has the advantages of excellent bonding performance and high strength.

Application examples:

1, is used for unloading and stripping the die. ���Rubber pad.

2、It has been widely used in blanking, bending, shallow drawing and forming processes.

Three, PU polyurethane rubber classification:

The traditional classification of polyurethane elastomers is based on processing methods[1], divided into cast polyurethane elastomer, mixing polyurethane elastomer and thermoplastic polyurethane elastomer. Due to the different raw materials used, synthesis and processing methods, and application purposes, reaction injection polyurethane elastomers (RIMPU) and solution-dispersed polyurethane elastomers have emerged. According to the formed form, it is divided into solid system and liquid system. It is also divided according to the chemical composition of the raw materials, generally divided into polyester or polyether, so there are polyether polyurethane elastomers and polyester polyurethane elastomers.

Four. PU polyurethane rubber vulcanization system:

There are three types of vulcanizing agents: isocyanate, peroxide and sulfur: Commonly used varieties of isocyanate vulcanizing agents are TDI and its dimers, MDI dimers and PAPI, etc., which can generate allophanate cross-linking bonds (easy to absorb water, pay attention to the environmental humidity when using). Products with good wear resistance, high strength and high hardness can be produced; dicumyl peroxide (DCP) is the most commonly used peroxide vulcanizing agent, and peroxide vulcanized PUE products have good dynamic properties. The compression permanent deformation is small, the elasticity and aging resistance are good, but the disadvantage is that it cannot be directly vulcanized with steam, and the tear strength is poor; PUE containing unsaturated segments can be vulcanized using a sulfur system, and the dosage is generally 1.5~2 parts to promote Agents M and DM are the most commonly used, generally around 6 parts, and vulcanized products have better overall performance.