The rubber layer at the bottom of a V-belt needs to withstand compressive stress during bending, maintaining the stiffness and shape of the belt. The compressive rubber layer is located at the bottom of the V-belt, supporting the core layer, which helps to increase the cross-section of the V-belt, enhance the friction surface with the pulley, and improve transmission efficiency. Typically, it is made from natural rubber, styrene-butadiene rubber, or neoprene rubber, and a moderate amount of reclaimed rubber powder can effectively reduce raw material costs.
1. Advantages of adding reclaimed rubber powder to the rubber V-belt compressive layer
The rubber used in the V-belt compressive layer requires good heat resistance, aging resistance, fatigue resistance, adequate hardness, low compressive deformation, and good lateral rigidity. A V-belt compressive layer made from a combination of natural rubber, neoprene rubber, and styrene-butadiene rubber can incorporate 10-30 parts of reclaimed rubber powder. This can effectively reduce raw material costs while ensuring the physical properties of the compressive layer.
60-mesh reclaimed rubber powder has a particle size of about 250 microns, which is considered medium-sized. It disperses well during mixing while maintaining some reinforcing performance. Proper use of reclaimed rubber powder in V-belt compressive layer rubber can moderately increase the hardness and structural stability of the rubber, enhance the rigidity of the compressive layer, and reduce permanent deformation during use. Additionally, the rough surface of the rubber powder helps improve wear resistance.
2. Reference formulation for adding reclaimed rubber powder to rubber V-belt compressive layer
Natural rubber 50 parts, styrene-butadiene rubber 50 parts, 60-mesh reclaimed rubber powder 20 parts, zinc oxide 5 parts, stearic acid 2 parts, adhesive 3 parts, antioxidant 2.5 parts, carbon black N330 35 parts, carbon black N660 5 parts, light calcium carbonate 40 parts, kaolin 40 parts, colophonium resin 6 parts, plasticizer 6 parts, accelerator 1.4 parts, sulfur 2.6 parts; total 268.5 parts.
3. Formulation design for rubber V-belt compressive layer with reclaimed rubber powder
When using reclaimed rubber powder to reduce costs in the V-belt compressive layer, carbon black can be used for reinforcement, preferably mixing high-abrasion carbon black with other types, in an amount of about 50 parts (E5LYY623). V-belt compressive rubber containing styrene-butadiene rubber can use medium or ultra-high abrasion carbon black. Moderately increasing the amount of zinc oxide in the vulcanization system can improve the thermal conductivity of the rubber. Adding 10-20 parts of short fiber can further increase the wear resistance and lateral rigidity of the compressive layer.
When adding 60-mesh reclaimed rubber powder to a V-belt compressive layer mainly made of natural rubber and styrene-butadiene rubber to reduce costs, it is recommended to pre-mix the rubber powder with the adhesive, then mix the carbon black with the raw rubber. In actual production, reclaimed rubber powder can also be added to other rubber belts, such as conveyor belt cover rubber, and further related studies can be conducted in the future.
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