How to improve the mixing uniformity of each component in the plastic formulation?

Appropriate top treatment of the components in the formulation prior to mixing can effectively improve the uniformity of the mixing system.

(1) Surface treatment of filler: mainly used for inorganic fillers, due to poor compatibility between inorganic fillers and organic resins, surface treatment of inorganic fillers, can improve compatibility with resins for better mixing uniform.

The inorganic filler is surface-organized and coated with JL-G series filler surface modifier/dispersant/activator to achieve hydrophobic treatment.

(2) Pre-heat treatment of the filler: Before mixing, it is possible to preheat the formulation components appropriately, and then remove some of the volatiles, and also accelerate the diffusion speed in the mixing and improve the mixing uniformity.

Feeding sequence

The components in the formulation are added in different order during the mixing process, and different mixing effects can be obtained.

1. Lubricants are generally added later to prevent friction between the materials after the addition, which affects the mixing effect.

2. For inorganic fillers with large oil absorption, when there are liquid components in the formulation, they should be added as much as possible. In case of being absorbed by unrelated components. For example, in the soft PVC formulation, when there is DOP and CaCO3, since CaCO3 has a large oil absorption, it should be added after the PVC and DOP are thoroughly mixed.

3. For heat-sensitive additives that are easily decomposed, they should be added last time to prevent the residence time at high temperature for too long, resulting in thermal decomposition.

Increased temperature

During the mixing process, increasing the mixing temperature promotes the diffusion and convection between the materials, accelerates the mixing between the materials, and improves the mixing uniformity. This method is particularly effective for mixing between solid components.

Increase speed

In the initial mixing, increasing the mixing speed can increase the convection between the materials, thereby effectively improving the mixing uniformity.

In the case of melt-kneading, the mixing speed is increased, and the shearing action between the materials can be improved to achieve the purpose of uniform mixing.

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. For example, the mixing between the powder and the powder and the pellets is much better than the mixing between the powder and the pellet.

Adding dispersing agent

The dispersant promotes the dispersion of the components in the formulation and prevents the formation of small pieces between the additives.

Common dispersants are: new JL-M01A/B series processing dispersion modifiers, low molecular weight polymers such as low molecular weight PP/PS.