PU Solid Rubber Rod is a solid rod material made of polyurethane (PU) elastomer as the base material through casting or extrusion. Polyurethane is a polymer material formed by the polymerization of isocyanate (Isocyanate) and polyol (Polyol) under the action of catalyst and chain extender. Its molecular chain structure has the dual characteristics of soft segment (flexible polyether/polyester segment) and hard segment (rigid urethane segment), which gives the material unique properties of high elasticity, high strength and wear resistance.
Polyurethane elastomer is called the "fifth engineering plastic" because its performance is between rubber and plastic. As a typical form of polyurethane elastomer, PU Solid Rubber Rod is widely used in mining machinery, automobile industry, petrochemical industry and other fields with its high load-bearing capacity, excellent oil resistance and fatigue resistance, and has become a high-end material solution to replace traditional rubber (such as NR, EPDM) and plastic (such as PVC, TPU).
Scientific characteristics and advantages analysis
Molecular structure and basic performance
Soft segment (flexible segment): Polyether PU (such as PTMEG) gives the material high elasticity and low-temperature toughness (glass transition temperature Tg as low as -60℃); polyester PU (such as adipic acid series) gives the material high strength and oil resistance (mineral oil expansion rate <5%);
Hard segment (rigid segment): Carbamate groups form a physical cross-linked network through hydrogen bonds, giving the material high modulus (tensile strength can reach 25-50 MPa) and high temperature resistance (heat deformation temperature HDT up to 80-120℃);
Microphase separation structure: The soft segment and the hard segment form microphase separation on the molecular scale. The soft segment provides elasticity and the hard segment provides support, achieving a balance between high elasticity and high strength.
Excellent mechanical properties
High elasticity and high load-bearing capacity
Tensile strength: The tensile strength of PU Solid Rubber rods is as high as 25-50 MPa (ordinary rubber such as NR is 10-20 MPa, TPU is 20-35 MPa), which can withstand higher loads (such as mine conveyor belt rollers, the load-bearing capacity of PU rods is 3-5 times higher than that of NR); Tear strength: ≥50 kN/m (ordinary rubber is 20-40 kN/m), excellent cutting resistance (suitable for mining machinery gears, oil drilling seals); Resilience: Compression permanent deformation ≤15% (70℃×24h, ISO 815 standard), ordinary rubber (such as SBR) compression permanent deformation is as high as 30%-50%, and it is not easy to deform after long-term use.
High hardness and wear resistance
Hardness range: Shore A 60 - 95 (adjustable), covering all scenarios from soft (such as seals) to hard (such as industrial rollers);
Wear resistance: Akron wear test ≤ 0.05 cm³/(1.61km) (ordinary rubber is 0.1 - 0.3 cm³/(1.61km)), service life is 5 - 10 times higher than NR (such as conveyor belt rollers, PU rods can be used for 5 - 10 years, NR rods are only 1 - 2 years).
Excellent chemical corrosion resistance
Oil resistance: PU Solid Rubber rods show extremely low expansion rate (≤5%, ordinary rubber such as NR expansion rate>20%) to mineral oil (such as hydraulic oil, gear oil) and synthetic oil (such as silicone oil), suitable for automobile gearbox seals and oil drilling parts;
Solvent resistance: Resistant to polar solvents (such as acetone, ethanol), but sensitive to strong oxidizing solvents (such as concentrated sulfuric acid, concentrated nitric acid) (need to avoid contact);
Acid and alkali resistance: Resistant to weak acids (such as phosphoric acid, acetic acid) and weak alkalis (such as sodium hydroxide solution, concentration ≤10%), but not resistant to strong acids (such as concentrated sulfuric acid) and strong alkalis (such as sodium hydroxide solution>20%). 2.4. Wide temperature range adaptability
Low temperature performance: The glass transition temperature Tg of polyether PU is as low as -60℃, and it can maintain high elasticity at -40℃ (suitable for polar equipment seals);
High temperature performance: The heat deformation temperature HDT reaches 80-120℃ (60-80℃ for ordinary rubber such as NR), and the short-term temperature resistance can reach 150℃ (suitable for automobile engine compartment seals).
Accurate dimensional stability
Water absorption: The saturated water absorption is only 0.3%-0.5% (1%-2% for ordinary rubber such as NR), and the dimensional change rate is ≤0.05% (0.5%-1% for ordinary rubber), which is suitable for precision parts (such as hydraulic cylinder piston rod seals);
Linear thermal expansion coefficient: 1.2×10⁻⁴/℃ (1.5×10⁻⁴/℃ for ordinary rubber), which is less affected by temperature changes (tolerance control ±0.02 mm).
Application fields
Mining and engineering machinery
Conveyor belt rollers: PU Solid Rubber rods are used for mine conveyor belt rollers, with remarkable wear resistance and load-bearing capacity, and a service life of 5-10 years;
Excavator bucket linings: High hardness PU rods (Shore A 85-95) are used for excavator bucket linings, and their impact resistance and wear resistance are better than high manganese steel linings.
Automobile industry
Automobile seals: PU Solid Rubber rods are used for automobile engine oil seals and gearbox oil seals, with excellent oil resistance and high temperature resistance;
Automobile shock absorber parts: Low hardness PU rods (Shore A 60-75) are used for automobile suspension shock absorber bushings, with compression permanent deformation ≤15%, providing a smooth driving experience.
Petrochemical and fluid transportation
Oil drilling seals: Oil-resistant PU rods are used for high-pressure seals in oil drilling, with a compressive strength of ≥10 MPa and a mineral oil expansion resistance of <5%;
Chemical pump impellers: Corrosion-resistant PU rods are used for chemical pump impellers, and their chemical corrosion resistance is better than that of ordinary rubber impellers.
Electrical and electronic appliances and home appliances
Electronic connector cushions: Low-hardness PU rods (Shore A 70 - 80) are used for mobile phones and computer connector cushions to reduce shock and resist impact;
Home appliance gears and transmission parts: Wear-resistant PU rods are used for washing machine reduction gears and air conditioner fan bearings, and the noise is lower than that of metal gears.
