Cast polyurethane rolls are rubber rolls produced by pouring liquid urethane. These rolls have become increasingly popular in various industrial applications due to their superior performance compared to traditional rubber rollers.
Understanding Polyurethane Rubber Rolls
1. **Characteristics and Types of Polyurethane Rubber Rolls**
Cast polyurethane rolls are made by pouring liquid urethane into molds, resulting in a high-performance material with exceptional properties. Compared to conventional rubber, they offer higher mechanical strength (2–3 times that of natural rubber), excellent wear resistance (5–10 times better than natural rubber), and outstanding compression resistance. They also feature a wide hardness range, with high elasticity even at high hardness—something other rubbers cannot match. Additionally, they provide a smooth surface finish, good machinability, and strong adhesion to metal cores, making them ideal for high-speed and high-pressure applications.
Polyurethane rolls are generally divided into three main types based on the soft segment: polyester, polyether, and polycaprolactone. Polyester-type polyurethane is commonly used in low to medium hardness rolls, offering good physical properties and solvent resistance, often found in non-ferrous metal industries. Polyether-type polyurethane is preferred for high-speed, high-hardness applications, such as printing and drawing rolls, due to its excellent water resistance, low-temperature performance, and processability. Polycaprolactone-type polyurethane offers a well-balanced set of properties, including good low-temperature resistance and hydrolysis resistance, and is often used in press rolls and high-demand applications.
2. **Basic Requirements for Polyurethane Materials in Rubber Rolls**
To ensure quality and performance, polyurethane materials must meet several key requirements:
- They must meet the physical and mechanical performance standards required for different types of rubber rolls.
- They should bond strongly with the roll core to meet bonding process demands.
- The hardness of the roller must be suitable and uniform across the surface.
- The surface must be free from bubbles, impurities, or mechanical damage.
3. **Key Technical Performance of Rubber Rolls**
(1) **Hardness**: Different types of rubber rolls require varying levels of hardness. For example:
- Squeeze roll: 80–90 Shore A
- Printing roll: 92–97 Shore A
- High-speed leather roll: 50–60 Shore A
- Mercerized roll: 85 Shore A
- Ink roll: 20–25 Shore A
- Cold roll: 85–95 Shore A
- Drying cylinder roll: 85–95 Shore A
- Drawing roll: 85–90 Shore A
- Felt roll: 95–100 Shore A
(2) **Surface Requirements**: Depending on the application, the surface may need to be smooth, textured, or treated with special coatings.
(3) **Medium-to-High Ratio**: This refers to the difference between the center diameter and the edge diameter of the roll. It helps compensate for deflection during operation and increases with the length of the roll.
Polyurethane rubber rolls have significantly improved over time, replacing many traditional rubber rolls in modern manufacturing processes. Their versatility, durability, and adaptability make them an essential component in various industries.
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A toilet seat is a component that is installed over the toilet bowl, also known as the seat for the person sitting on the toilet. Its main function is to provide a comfortable and hygienic environment for use. Here are some details about the common toilet seat cover:
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Comfort: toilet seats are usually designed with the user's comfort in mind, with materials and shapes carefully selected and designed to ensure comfort during use.
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Hygienic: Toilet lids help to keep the toilet hygienic by preventing the inside of the toilet from coming into direct contact with airborne contaminants such as dust and bacteria. Additionally, covering the toilet lid also reduces the spread of odours created when flushing.
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Durability: Toilet lids are usually made of durable and easy-to-clean materials that can withstand the friction of daily use and cleaning agents and are not easily damaged.
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Aesthetics: The design of the toilet seat also takes into account the overall aesthetics of the bathroom, and its colour, shape and style are usually in harmony with the toilet and the overall style of the bathroom.
In addition to the above basic functions, some toilet seat also has a special design, such as with a slow-down function of the toilet seat, you can avoid the noise generated by the sudden closure of the toilet seat; or with an antibacterial coating of the toilet seat, you can effectively inhibit the growth of bacteria.
In short, although ordinary toilet seat seems simple, it plays an important role in daily life, providing convenience and comfort for our life.
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