Common sense of polyurethane properties

Polyurethane elastomer: also known as superior glue, beef tendon king. Because it has significant advantages such as high strength, large elasticity, small deformation, and good stretching force. It has been widely used in the stamping industry of metal processing. Known as "pressure fluid mold" and "strong spring strip", using polyurethane as the mold material can greatly shorten the mold making time, relax the fit gap, and reduce the mold making cost. The stamped product can meet the requirements of no burr in the incision, full edges and corners, and high yield.

Polyurethane (PUR) refers to a large class of polymers containing more urethane groups on the main chain of the molecule. It is a polymer material between plastic and rubber. It has a large elongation. , Wide range of hardness, wide range of formula adjustment, excellent wear resistance and mechanical properties. Casting polyurethane elastomer (CPUR) is the most important one of the three processing types of polyurethane elastomers. Its dosage accounts for 60% of the amount of PUR. It has diversified chemical structure, easy adjustment of viscosity, excellent processing technology and easy It has the advantages of industrial production, convenient use and fast curing, so it is very suitable for making large and complex components. Polyurethane wear-resistant liner is produced and processed by casting polyurethane elastomer process. Polyurethane is a type of polymer containing urethane-type repeating structural units in the macromolecular chain. PU is a product reflected by polyisocyanate and polyether or polyester polyol in a certain proportion.

Properties of PU elastomers: The properties of PU elastomers are slightly different from those of PU elastomers synthesized from plastic polyols. Polyester PU has high mechanical properties, good oil resistance, but poor water resistance; polyether PU has better low temperature resistance and hydrolysis resistance than polyester type, but oil resistance and mechanical properties are slightly worse. Corrosion-resistant, hydrolysis-resistant, wear-resistant polyurethane seals, diaphragms, oil seals, etc.

Mechanical properties of PU: The hardness of PU elastomers varies widely, ranging from Shore A10 to D80, and the elongation at break is as high as 600% ~ 800%. The highest Shore hardness of natural rubber is only A70, and the elongation at break is 550%. The tear strength of PU elastomer is higher, which is 2~5 times larger than that of natural rubber. PU elastomer has high resilience and good shock absorption effect. The wear resistance of PU elastomer is good, which is 3~10 times that of natural rubber.

Polyurethane features: 1. Wide range of hardness. It still has the elongation and resilience of rubber at high hardness. The hardness range of polyurethane board is Shore A10-D80. 2. High strength. Their tear strength, tear strength and load-carrying capacity are much higher than general purpose rubbers at rubber hardness. At high hardness, its impact strength and flexural strength are much higher than those of plastics. 3. Wear-resistant. Its wear resistance is very outstanding, generally in the range of 0.01-0.10 (cm3)/1.61km, which is about 3-5 times that of rubber. 4. Oil resistance. Polyurethane board is a kind of strong polar polymer compound, which has little affinity with non-polar mineral oil, and is hardly corroded in fuel oil and mechanical oil. 5. Good oxygen and ozone resistance. 6. Excellent vibration absorption performance, can be used for vibration reduction and buffering. In the mold manufacturing industry, it can replace rubber and springs. 7. Has good low temperature performance. 8. Radiation resistance. Polyurethane has good resistance to high-energy rays, and still has satisfactory performance under the radiation dose of 10-10 g. 9. Has good machinability. (turning, milling, grinding and drilling are available)

Applications: Suitable for shock-absorbing pads, pads, springs for metallurgy, mining, petroleum, automobiles, building materials, sports, heavy machinery, large stamping equipment, and punching dies for various metal plates and pipes. The friction of general mechanical equipment acts as a buffer or shock absorber, and is an ideal die spring. All kinds of machinery dedicated.