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How do temperature and time affect the quality of casting polyurethane prepolymers?
Views: 96 | Update Date: Oct 16 , 2020

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...

How does acidity and alkalinity affect the quality of urethane prepolymers?
Views: 79 | Update Date: Oct 12 , 2020

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...

How does moisture affect the quality of prepolymers for cast urethane?
Views: 103 | Update Date: Sep 29 , 2020

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...

PU elastomer production process- step 3
Views: 115 | Update Date: Sep 23 , 2020

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  ...

PU elastomer production process- step 2
Views: 87 | Update Date: Sep 15 , 2020

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...

PU elastomer production process- step 1 Dehydration of oligomeric polyols
Views: 97 | Update Date: Sep 09 , 2020

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...

Characteristics and classification of urethane spring
Views: 119 | Update Date: Sep 03 , 2020

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...

Characteristics and types of polyurethane roller
Views: 148 | Update Date: Aug 25 , 2020

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,...

What is the advantage of polyurethane bushings?
Views: 138 | Update Date: Aug 19 , 2020

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...

What is semi prepolymer method of PU ?
Views: 136 | Update Date: Aug 13 , 2020

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...

Latest the Inquiries of Pepsen Urethane Bushings in July, 2020
Views: 160 | Update Date: Aug 09 , 2020

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...

Synthesis of polyurethane
Views: 143 | Update Date: Aug 06 , 2020

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...

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