Release time:

2020-11-26

What are the mixing principles of an open mill? The mixing process of an open mill generally includes three stages: wrapping, feeding, and mixing. (1) Wrapping Several states of rubber in an open mill: 1—Rubber is difficult to enter the roll gap; 2—Tightly wrapped around the front roll; 3—Forms a bag-like shape after leaving the roll; 4—Viscous flow wrapping the roll (2) Feeding Before the rubber is wrapped around the roll and the compounding agents are added, an appropriate amount of rubber should be accumulated at the upper end of the roll gap. Appropriate accumulation is a necessary condition for feeding. (3) Mixing Circumferential direction: Most even mixing; Axial direction: Uneven; Radial direction: Least even Factors Affecting Open Mill Mixing 1. Rubber Loading Capacity The rubber loading capacity should be reasonably determined based on the specifications of the open mill and the characteristics of the rubber compound. Excessive capacity reduces the mixing dispersion effect, increases the mixing temperature, and easily causes scorching, affecting the quality of the rubber compound; insufficient capacity reduces production efficiency. Formula: V—Rubber loading capacity, L; D—Roll diameter, cm; L—Roll length; 2. Roll Gap The roll gap is generally 4-8mm. Reducing the roll gap increases the shearing effect, but also increases heat generation. 3. Mixing Temperature If the roll temperature is too low, the rubber hardness is too high, and the equipment is easily damaged. Increasing the roll temperature helps reduce the viscosity of the rubber and accelerate the mixing and feeding speed, but if the temperature is too high, it can easily cause the rubber to leave the roll and scorch, making it difficult to operate. The roll temperature is generally maintained between 50-60℃ through cooling. However, when mixing rubber compounds containing high-melting-point compounding agents (such as high-melting-point coumarone resin), the roll temperature needs to be appropriately increased.