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With the development of the economy, the application of vacuum feeding machines is becoming increasingly widespread. The conveying system of the vacuum feeder can be used in conjunction with major process equipment such as mixers, granulators, screening machines, coating machines, filling machines, packaging machines, vibrating screens, and reaction vessels. The process of particle size reduction of solid materials, polymer gel and liquid drops in the vacuum feeder is collectively referred to as "dispersion mixing". In order to achieve the required product quality specifications, there is a dispersing and mixing effect in the typical vacuum feeding machine processing process, which mainly has the following functions:

(1) Mix organic or inorganic pigments with color masterbatch.

(2) Crush high molecular weight particles to achieve homogenization of the polymer melt.

(3) Mixing of incompatible polymer blends.

The dispersion mixing effect is the result of shear stress acting on a single particle, and the level and duration of shear stress acting on the particle are parameters that affect dispersion mixing. The crushing process of solid particles in polymer melts is similar to fatigue failure. Therefore, in addition to the smaller shear stress required for dispersion mixing, a shorter residence time is also required. After reaching a shorter residence time and smaller shear stress, the magnitude of stress and the length of residence time have an equivalent effect on dispersion and mixing. The relationship between shear force and residence time required to achieve the same dispersion quality when the carbon black content is constant. The smaller the value, the worse the dispersion effect. The wide engagement disc in the kneading section is an element that generates high shear stress at the gap between the inner walls of the vacuum feeder cylinder. To control the temperature rise caused by friction within a reasonable range, it is necessary to use forced cooling for the barrels of these key parts; In addition, forced cooling can increase the viscosity of the material.

Different methods for determining the quality of color masterbatch mixtures have been established in laboratories and technical research, regardless of their purpose. Let's discuss them in detail below.

1. The vacuum feeder mixes the mother material and natural material and injects thin sample pieces, which are then compared with standard samples to determine their mixing quality.

2. Cut thin slices of 40 microns from the diluted sample using a slicer, observe them under a microscope, and compare them with standard samples to determine their grade.

3. Pressure filtration test. This method can lead to more representative conclusions. It is a new development in the quality grade determination method of masterbatch, and has been used in practice for some time. The method is to add the premix of masterbatch and color masterbatch to a vacuum feeder for melting plasticization and mixing. A gear pump is installed at the entrance of the experimental head to measure and establish pressure. Pass the mixture melt through the filter plate at the outlet of the ancient machine head.