Polyurethane rollers are a key equipment component widely used in modern industry. Due to their excellent physical properties, especially high elasticity, wear resistance, corrosion resistance and impact resistance, they are widely used in printing, papermaking, rubber processing, steel metallurgy and other industries. As a high-performance material, polyurethane performs well in the manufacture of rollers, and its excellent comprehensive performance enables it to play an important role in various complex working conditions.

However, the performance and service life of polyurethane rollers are closely related to the composition, formulation and processing technology of its materials. Therefore, understanding the material composition of polyurethane rollers is crucial to optimizing the performance of rollers, extending service life and improving production efficiency.

This article will explore the material composition of polyurethane rollers in depth, analyze the main components and proportions of the materials used in polyurethane rollers and their effects on performance, so as to provide a theoretical basis for the selection and manufacture of polyurethane rollers in industrial production.

What is polyurethane?

Polyurethane is a polymer material synthesized by chemical reaction between isocyanates and polyols. The composition of polyurethane has great flexibility due to different production processes, uses and performance requirements. The basic composition of polyurethane usually includes the following major components:

Isocyanates

Isocyanates are one of the key reactants in the synthesis of polyurethane. They play a decisive role in the hardness, wear resistance and heat resistance of polyurethane. Commonly used isocyanates are:

● Toluene diisocyanate (TDI): commonly used in the production of soft and medium hardness polyurethanes, with good flexibility and elasticity.

● Diphenylmethane diisocyanate (MDI): suitable for the production of hard polyurethanes, with good wear resistance and thermal stability, and often used to make high-hardness polyurethane rollers.

● Highly chlorinated diisocyanate (HDI): commonly used to make polyurethane materials with stronger elasticity, usually used in coatings and coatings.

Polyols

Polyols are another key component in the synthesis of polyurethanes. The molecular structure of polyols determines the elasticity, hardness and strength of polyurethanes. Common polyols include:

● Polyether polyols: Polyether polyols are the most commonly used type of polyols, with good elasticity, weather resistance and water resistance. It is used to make soft and medium-hard polyurethanes.

● Polyester polyols: Polyester polyols have a tighter molecular structure and are usually used to make hard polyurethanes with good heat resistance and mechanical strength.

● Amino alcohols and epoxy alcohols: These polyols are used in certain specific formulations to improve the impact resistance, wear resistance or chemical resistance of polyurethanes.

Catalysts

The synthesis process of polyurethane requires catalysts to accelerate the reaction between isocyanates and polyols. Commonly used catalysts include amine catalysts, metal catalysts, etc., which can control the reaction speed, reaction temperature, and the molecular weight and cross-linking degree of the final polyurethane.

Chain Extenders

Chain extenders are some low molecular weight compounds that can react with prepolymers. Their function is to increase the chain length of polyurethane molecules, increase the molecular weight of polyurethane, and thus improve the physical properties of polyurethane. For example, commonly used chain extenders include 1,4-butanediol, ethylene glycol, etc.

Crosslinkers

Crosslinkers are used to form chemical crosslinking structures between polyurethane molecular chains, thereby enhancing the strength, hardness, wear resistance and temperature resistance of polyurethane. The addition of crosslinkers will significantly improve the durability and rigidity of polyurethane.

Fillers and Plasticizers

In polyurethane, fillers are usually used to enhance the rigidity, heat resistance and compression resistance of the material. Common fillers include calcium carbonate, talcum powder, silicates, etc. Plasticizers are used to improve the processing properties of polyurethane, making it more flexible and plastic. Common plasticizers include phthalates.

Stabilizers and Antioxidants

Polyurethane is prone to oxidation at high temperatures and when exposed to air, affecting its performance and service life. For this reason, manufacturers often add antioxidants, UV stabilizers, etc. to the formula to improve the anti-aging properties of polyurethane.

What are the material compositions of polyurethane rollers?

The performance of polyurethane rollers directly depends on the composition of its materials and the design of the formula. Different types of polyurethane rollers use different raw material ratios and processing techniques, so their final performance is also different. The following is an analysis of the relationship between the material composition and performance of polyurethane rollers:

1. Relationship between hardness and elasticity

The hardness of polyurethane rollers is determined by the type, ratio and degree of crosslinking of isocyanate and polyol in its material composition. Polyurethane rollers with higher hardness usually use a higher proportion of MDI and hard polyols, which makes the polyurethane material have better mechanical strength and wear resistance. In contrast, polyurethane rollers with lower hardness often use TDI and flexible polyols, which have better elasticity and adaptability.

● Hardness: The hardness of polyurethane rollers is usually adjusted by changing the type of polyol (such as using polyether polyols and polyester polyols) and its molecular weight. Higher hardness helps to improve the wear resistance of the roller, but may sacrifice its elasticity and impact absorption capacity.

● Elasticity: The elasticity of polyurethane is determined by the flexible chain segment of its molecular structure. Polyurethane rollers with low hardness have higher elasticity and are suitable for occasions requiring larger compression deformation and elastic recovery.

2. Relationship between wear resistance and impact resistance

The wear resistance and impact resistance of polyurethane rollers are closely related to the crosslinking degree and hardness of their molecular structure. Polyurethanes with higher hardness and higher crosslinking degree have stronger wear resistance, but may sacrifice some impact resistance. Polyurethanes with lower hardness and more flexible molecular chains show better impact resistance, but relatively poor wear resistance.

● Wear resistance: By selecting polyurethane materials with high crosslinking degree and higher hardness, the wear resistance of the roller can be greatly improved, which is suitable for high-speed and high-load working environments.

● Impact resistance: In some specific applications, impact resistance is more important than wear resistance. At this time, polyurethane rollers usually use a formula with lower hardness and higher elasticity to ensure that brittle fracture does not occur under force impact.

3. Chemical resistance and heat resistance

The chemical resistance and heat resistance of polyurethane rollers are usually closely related to the selection of polyols, isocyanates and additives in their material composition. For example, polyurethanes containing a higher proportion of polyester polyols generally show better oil resistance and acid and alkali resistance, while polyurethanes containing polyether polyols have advantages in water resistance and cold resistance. By adjusting the proportions of these components, polyurethane rollers with different chemical resistance can be manufactured.

● Chemical resistance: The chemical resistance of polyurethane is mainly optimized by selecting the appropriate type of polyol (such as polyester polyol) and cross-linking agent. Polyurethanes with good chemical resistance are suitable for environments in contact with corrosive liquids or gases.

● Heat resistance: The heat resistance of polyurethane is usually related to its degree of cross-linking and the type of isocyanate used (such as MDI, HDI). Polyurethane rollers in high-temperature working environments need to have strong thermal stability and low thermal expansion coefficient.

Optimization and application of polyurethane roller material composition

Depending on different application requirements, the material composition of polyurethane rollers needs to be finely optimized. In actual production, engineers will adjust the formula of polyurethane rollers according to factors such as working environment, load conditions, required wear resistance, impact resistance and chemical resistance, so as to manufacture polyurethane rollers that meet specific needs.

During the production process, through the precise control of the raw material selection, proportion and processing technology of polyurethane, polyurethane rollers with a wide range of hardness, excellent wear resistance and impact resistance can be manufactured. At the same time, the use of suitable fillers and stabilizers can help to further improve the comprehensive performance of polyurethane rollers and ensure their stability and reliability under extreme working conditions such as high load, high temperature and high speed.

JH Machinery is a leading supplier of customized industrial rolls, offering solutions tailored to diverse industries. Since 2001, our ISO9001-certified factory has been producing high-quality products, including cooling rolls, mirror rolls, and rubber rolls. We serve industries such as automotive, mining, and packaging, ensuring precision and reliability in every order. With competitive pricing, bulk purchasing options, and exceptional after-sales service, JH Machinery is your trusted partner in China.