During the production process, if the surface of the color masterbatch is found to be not smooth, first check whether the extrusion temperature is appropriate. Extrusion temperature: If the temperature of the flame head is too high or too low, it can cause surface roughness; If the extrusion temperature is appropriate, it is necessary to consider whether the dispersibility of the pigment is good. If the molecules of the pigment are too hard, they will be poorly dispersed in the plastic, resulting in a rough surface; Dispersants (polyethylene wax) with low molecular weight or excessive addition may precipitate onto the surface during the processing of color masterbatches, causing mold paste, resulting in an unsmooth extrusion strip surface and poor particle surface roughness and light sensitivity.

Common defects of color masterbatch

1. Why do products injected by different injection molding machines have different shades of color for the same color masterbatch, resin, and formula?

This is often caused by the injection molding machine. Due to differences in manufacturing, usage time, or maintenance status, different injection molding machines may have different mechanical states, especially the difference in the tightness between the heating element and the material barrel, resulting in different dispersion states of the color masterbatch in the material barrel. This phenomenon can occur.

2. Will pigment migration during storage of color masterbatch affect the quality of the product?

Some color masterbatches have high pigment content (or dyes), in which case migration is normal. Especially when dyes are added to the masterbatch, serious migration occurs. But this does not affect the quality of the product, as after the color masterbatch is injected into the product, the pigment is at a normal color concentration in the product.

3.1 After changing to another brand of resin, the same color masterbatch and formula, but the color has changed. Why is this?

The density and melt index of different grades of resin may vary, resulting in differences in the performance of the resin compared to the color masterbatch

Compatibility may also vary, leading to color changes. Generally speaking, as long as the density and melt index do not differ significantly, the color difference will not be too significant. The color can be corrected by adjusting the amount of masterbatch.

3.2 After using color masterbatch, the product get easy to crack

This may be due to poor diffusion and miscibility caused by the poor quality of dispersants or additives used by the manufacturer, which affects the physical and mechanical properties of the product.

4. After using according to the proportion specified in the color master manual, the color is too dark or too light

Although this question is simple,
However, there are many possibilities.

5. Under sunlight, there are stripes in the product

5.1This issue needs to be considered from two aspects: the physical and mechanical properties of plastics and the plastic forming process:

The temperature of the injection molding equipment is not well controlled, and the color masterbatch cannot be fully mixed with the resin after entering the mixing chamber.

The injection molding machine did not apply a certain amount of back pressure, and the mixing effect of the screw was not good.

5.2 Poor dispersion of color masterbatch or poor resin plasticization.

In terms of technology, the following adjustments can be made: 1. Increase the temperature of the mixing chamber near the discharge port slightly; 2. Apply a certain amount of back pressure to the injection molding machine.

If the above debugging still does not work well, it may be due to the dispersion or matching problem of the color masterbatch and resin, you should contact with color masterbatch manufacturer.

  • 6.1. Color masterbatch not carefully tested, with too little or too much pigment
  • 6.2. Inaccurate measurement during use, a lot of enterprises, especially small enterprises, measuring at will
  • 6.3. There is an issue with the matching between the color masterbatch and the resin, which may be due to improper carrier selection of the color masterbatch or the manufacturer’s arbitrary change of resin variety
  • 6.4. Improper machine temperature and prolonged retention of color masterbatch in the machine

Processing procedure: Firstly, check whether the resin variety matches the color masterbatch and whether the measurement is accurate. Secondly, adjust the machine temperature or speed. If there are still problems, please contact the color masterbatch manufacturer.