The reaction temperature and time have a significant effect on the rate of prepolymer formation and the chemical structure of the prepolymer. When there is no catalytic reaction, carbamate is mainly formed below 100°C, and urea is also formed when water is present; above 100°C, biuret and allophanate are also...

No matter it is the prepolymer synthesis reaction or various other reactions for the synthesis of CPU, it is related to the acidity and alkalinity in the reaction system. Acid and basic impurities mainly act as catalysts. The acidic medium is conducive to the chain extension reaction to generate carbamate and...

The main factors affecting the quality of prepolymers is whether high-quality raw materials are used to synthesize products. For oligomer polyols, the indicators that should be controlled include hydroxyl value, acid value, moisture, metal impurities, color and unsaturation (PPG), etc. For polyisocyanates, the...

Synthesis process of prepolymer The synthesis process of prepolymer can be divided into laboratory method and industrial production method. The latter has manual batch method and mass production method. They will be introduced separately below. (1)   Laboratory method  ...

Prepolymer synthesis Formulation design Different application fields have different requirements for product performance, and the performance of the product depends on the raw materials and their ratio and processing technology. Therefore, before making CPU products, the qualified raw materials should...

The moisture content of oligomeric polyols should be less than 0.05% no matter how to produce CPU products. If the value is higher than this value, the dehydration operation should be carried out. The most commonly used methods are intermittent water removal, continuous spray dehydration and continuous membrane...

In recent years, urethane materials have been widely used because of their higher strength. Rubber and polyurethane materials, because of their high elasticity, good wear resistance, sound insulation and damping characteristics, are used in automobile, ordnance, aerospace, chemical industry and other damping and...

Casting polyurethane roller is a kind of roller made by pouring liquid polyurethane rubber. Compared with ordinary rubber rollers, it has higher mechanical strength (2-3 times of natural rubber), excellent wear resistance (5-10 times of natural rubber), outstanding compression resistance; wide range of hardness,...

Polyurethane bushing is a ring sleeve that acts as a gasket. In the valve application field, the bushing is in the valve cover, and generally uses corrosion-resistant materials such as polytetrafluoroethylene or graphite for sealing.   Function of polyurethane bushing   The valve...

If the isocyanate index (NCO / OH) is greater than 2, there will be excess isocyanate monomer in the prepolymer. If NCO / Oh ≫ 2, the product is actually a mixture of isocyanate terminated prepolymer and isocyanate monomer. This mixture is called a semi prepolymer.   The semi prepolymer method...

Polyurethane bushings are manufactured at Pepsen from 2004 when rubber bushings were widely replaced by polyurethane bushings in China. Our durable custom polyurethane bushings can be molded or machined depending on hardness, quantity and shape. Polyurethane bushings have been widely used in vibration isolation...

According to the synthesis process of CPU elastomer, it can be divided into one-step method and two-step method, the latter is also called prepolymer method, and prepolymer method can be divided into prepolymer method and semi prepolymer method. Prepolymer method is to synthesize prepolymer...