Vulcanized rubber powder is a powdery substance of different particle sizes made from waste rubber, processed by mechanical processing, crushing, or grinding. It can be combined with rubber or other polymer materials to produce new materials, with tires being one of its key application areas. The reasonable use of vulcanized rubber powder in tire compounds can not only reduce raw material costs but also optimize processing performance, further improving tire processing stability and finished product quality.
1. Key points of the mixing process for tire compound mixed with vulcanized rubber powder
The mixing process directly determines the dispersion effect of vulcanized rubber powder in tire compounds and the overall processing performance of the compound, and is often produced using two-stage, three-stage, or multi-stage mixing processes. Vulcanized rubber powder is generally added to the mixer together with raw rubber. By appropriately adjusting mixing temperature, rotor speed, and mixing time, mechanical shear force and heat action fully wet the rubber powder and evenly disperse it in the compound, effectively preventing powder agglomeration from affecting its properties. When mixing tire compounds mixed with vulcanized rubber powder, it is recommended to raise the discharge temperature by 5-10°C and appropriately extend the mixing time.
After adding vulcanized rubber powder to tire compounds, the residual accelerators and activators on the powder surface are gradually released during mixing, increasing overall compound activity and slightly shortening scorching time. Strict temperature control during mixing and extrusion stages effectively prevents scorching and ensures production stability.
2. Vulcanized rubber powder improves tire compound extrusion processes
The extrusion process directly affects the dimensional accuracy, surface quality, and production efficiency of finished tire products. Vulcanized rubber powder plays the following three roles in the tire compound extrusion process.
(1) Vulcanized rubber powder can improve the rheological behavior of tire compounds, enhancing the affinity among the compound and the rollers; Tire compounds mixed with vulcanized rubber powder have good roller wrapping properties during hot mixing, with no strips or sticking to the glue supply.
(2) Vulcanized rubber powder can reduce the extrusion expansion rate of tire compound, suppress elastic shrinkage, stabilize the dimensions of semi-finished products, and provide good stiffness, which is more beneficial for subsequent molding processes, especially for areas with strict dimensional requirements such as sidewalls and bead wrapping.
(3) Vulcanizing rubber powder can enhance the adhesion and cohesion of tire compounds, improving the structural stability of semi-finished products; During forming and bonding, the joints of the extruded parts are firm and not easily detached.
3. Vulcanized rubber powder improves the vulcanization process of tire compounds
The vulcanized rubber powder forms tiny channels at the contact surface with the mold, which helps air escape, improves the flow of the compound, and reduces the occurrence of glue shortages and bubbling in finished tire products; Glue powder particle size and surface E5LYY1222 treatment state have a significant impact on exhaust performance. It should be noted that although the addition of rubber powder improves exhaust and flow, it does not mean that the requirements for venting operations can be relaxed. For structurally complex tire components, strict exhaust procedures must still be followed to ensure sufficient air is expelled from the mold cavity.
In actual production, different parts of tire rubber have different performance requirements, so the types and amounts of vulcanized rubber powder used vary greatly. We will share with you a low-cost formula for tires mixed with vulcanizing rubber powder in the future.
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