CASECASE

CASE06

Rubber modifier

Improves the abrasion resistance and sliding properties of various rubbers. Hardness adjustment is also possible.

Characteristics of rubber additives using MIPELON^™

Abrasion resistance, sliding properties, chemical resistance, hardness adjustment

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.

Figure 2: Particle sizes around the average value

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^™

Measuring the differences in abrasion resistance when MIPELON^™ and PTFE are added to EPDM shows that abrasion loss is reduced by around 45% when MIPELON^™ is added at 40 PHR. 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 best suited to applications designed to improve abrasion resistance, extend component life and enhance the reliability of equipment. 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.