1. Pretreatment of materials
In the mixing of money, proper pretreatment of the components in the formula can effectively improve the mixing uniformity.
Surface treatment of additives:
Mainly used for inorganic additives, because the compatibility between inorganic additives and organic resins is not good.The additive is subjected to hydrophobic treatment with an additive such as a coupling agent, a surfactant, or the like to improve the uniformity of mixing with the resin.
Pretreatment of additives:
Proper preheating of the formulation components prior to mixing accelerates the diffusion rate during mixing and improves mixing uniformity.
2. Feeding sequence
Different components in the formula are added in the mixing process, and different mixing effects can be obtained.
Lubricants are generally added later to prevent friction between the materials after the addition, affecting the mixing effect.
For inorganic additives with high oil absorption, when there are liquid components in the formulation, they should be added as much as possible to prevent absorption by unrelated components.
For heat-sensitive additives that are easily decomposed, they should be added last to prevent excessive residence time at high temperatures, resulting in thermal decomposition.
For high-filling formulations, it is difficult to mix the fillers once, often adding half of the main feed port. After the melt is mixed evenly, add the other half to the side feed port.
3. Improve process conditions
A . Increasing the temperature Increasing the mixing temperature during the mixing process promotes the diffusion and convection between the materials, accelerates the mixing between the materials, and improves the mixing uniformity.
B. Increase the speed In the initial mixing, increase the mixing speed, increase the convection between the materials and improve the mixing uniformity. In the melt-kneading, the mixing speed is increased, the shearing effect between the materials is improved, and the mixing uniformity is improved.
C. Particle size uniformity The closer the particle sizes of the various additives in the formulation are to each other, the higher the uniformity of mixing.
4. Add dispersant
Paraffin, stearic acid and other dispersing agents can promote the dispersion of the components in the formulation and prevent the formation of small pieces between the additives.
Post by Shelley