Characteristics of rubber additives using MIPELON™
Abrasion resistance, sliding properties, chemical resistance, hardness adjustment
CASECASE
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CASE06
Rubber modifier (PTFE substitute)
Improves the abrasion resistance and sliding properties of various rubbers. Hardness adjustment is also possible.
Examples of use and evaluation
Rubber rolls, rubber stoppers for pharmaceutical vials, belts, hoses
Issues with rubber materials
Rubber is an important item that has supported people's lives since ancient times. Its characteristics are that it is soft, stretches, and returns to its original state when left alone. It is said that there are no other materials that can substitute for these characteristics. Today, various forms of synthetic rubber exist in addition to natural rubber, such as ethylene rubber and chloroprene rubber, and these are used in all facets of our lives from automobiles to industry. However, although rubber has excellent properties such as its strength, there are some cases where it cannot produce the required physical properties when used on its own. In particular, in recent years amid the trend towards addressing the SDGs, there have been increasing demands to improve elements of performance such as durability and abrasion resistance.
Solution
MIPELON™ is a fine-particle ultra-high molecular weight polyethylene. Using MIPELON™ as a rubber additive can improve the abrasion resistance and sliding properties of the rubber. As Figure 1 shows, MIPELON™ XM220 particles have an average diameter of 30 μm. Due to Mitsui Chemical's proprietary manufacturing technologies, MIPELON™ particles have a characteristic spherical shape compared with other U-PE varieties. Additionally, as the figure below shows, there is a narrow distribution of particle sizes around the average value, producing uniform particle sizes. Compared with other additives used to reduce the friction and abrasion of rubber, MIPELON™ displays the lowest friction coefficient.
MIPELON™ additive
As MIPELON™ is a polyethylene, it features excellent compatibility with olefin-based rubbers such as EPDM. The typical process used to blend MIPELON™ with EPDM rubber involves adding MIPELON™ to a 100ºC EPDM mixture at 10 - 40 PHR, together with carbon black and process oil. Additionally, as the melting point of MIPELON™ is 136°C, a blending temperature of 130ºC or below is suitable for blending rubber and MIPELON™. If the temperature is higher than this, the particles could clump together and become poorly dispersed in the rubber.
Effects of adding MIPELON™
When we measured the difference in wear resistance when adding MIPERON™ and PTFE, a fluororesin, to EPDM, we found that the wear loss was reduced by approximately 45% when 40 phr of MIPERON™ was added. Abrasion loss declines as the amount of MIPELON™ XM220 added is increased between 10 and 40 PHR. MIPELON™ particles are self-lubricating and this property helps improve abrasion resistance. Adding MIPELON™ can also lower the density of the rubber, making it possible to manufacturing rubber products with high abrasion resistance at lighter weights. Additionally, MIPELON™ does not affect strength properties such as tensile strength or compression set.
Examples of MIPELON™ applications
MIPELON™ can be used for the manufacturing of industrial rolls such as OA rolls and to modify the properties of belts for products such as conveyors and motorcycles. It is suitable for applications where it is desired to improve wear resistance, improve the life of parts and the reliability of equipment, and since it is PAFS-free, it is a promising product as a substitute for PTFE. Additionally, MIPELON™ is an olefin-based substance that is compliant with FDA and GB standards, is not harmful to humans, and is also suitable to the manufacturing of rubber for medical use, such as rubber stoppers for pharmaceutical vials.
Summary
MIPELON™ can improve the abrasion resistance of rubber, chiefly EPDM. It also produces various other effects such as helping to reduce weight, improving hardness, and not impacting tensile strength or compression set.