Nine common problems of color masterbatch

1. Under sunlight, there are striped pigment bands in the product

This question needs to be considered from two aspects: the physical and mechanical properties of the plastic and the plastic molding process:

Influence of plastic physical and mechanical properties:

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

2. The injection molding machine does not add a certain amount of back pressure, and the mixing effect of the screw is not good.

3. The dispersion of the color masterbatch is not good or the resin plasticization is not good.

The process can be debugged as follows:

1. Slightly increase the temperature of the part of the mixing cavity near the discharge port

2. Apply a certain back pressure to the injection molding machine.

If it is still not good after the above debugging, it may be a problem of the dispersion or matching of the color masterbatch and resin, and the masterbatch manufacturer should be contacted to solve it.

2. After using a certain color masterbatch, the product appears to be easier to break

This may be due to poor diffusion and mutual solubility caused by the poor quality of the dispersant or auxiliary selected by the plastic machining manufacturer, which affects the physical and mechanical properties of the product.

3. The color is too dark (too light) after using according to the proportion on the masterbatch instruction

Although this problem is simple, there are many possibilities, specifically:

1. The color masterbatch has not been tested carefully, and the pigment is too little or too much

2. The measurement is inaccurate when used, and there are a lot of random measurement by domestic enterprises, especially small and medium-sized enterprises

3. There is a problem with the matching of color masterbatch and resin. This may be caused by improper selection of the carrier of the color masterbatch, or the manufacturer may change the resin variety at will

4. The temperature of the machine is improper, and the color masterbatch stays in the machine for too long

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

4. Under the same conditions, the colors of the products injected by different injection molding machines have different shades

This is often caused by the injection molding machine. Different injection molding machines have different mechanical conditions due to different manufacturing, use time or maintenance conditions, especially the difference in the degree of close contact between the heating element and the barrel, which makes the dispersion state of the color masterbatch in the barrel different. The phenomenon will appear.

5. After changing to another brand of resin, the color has changed

The density and melt index of different grades of resin will be different, so the performance of the resin will be different, and the compatibility with the color masterbatch will also be different, resulting in a color change. Generally speaking, as long as the density and melt index are not different If the color difference is large, the color difference will not be too large, and the color can be corrected by adjusting the amount of color masterbatch.

6. Does the migration of pigments that occur during the storage of the color masterbatch affect the product quality?

Some color masterbatches have high pigment content (or dyes). In this case, migration is normal. Especially the color masterbatches added with dyes will cause serious migration. But this does not affect the quality of the product, because after uhmw machining into the product, the pigment is in the normal color concentration in the product.

7. Why do some injection products have poor gloss?

There are many possibilities:

1. The nozzle temperature of the injection molding machine is too low

2. The mold finish of the injection molding machine is not good

3. The product molding cycle is too long

4. Too much titanium dioxide contained in the color masterbatch

5. The dispersion of color masterbatch is not good

8. After a period of time, some plastic products will fade

The basic pigments used by machining uhmw plastic manufacturers are of poor quality and drift.

9. Why ABS color masterbatch is particularly prone to chromatic aberration?

Different brands of ABS produced in various countries have a large color difference, even if the same brand of ABS, each batch number may exist. However, this chromatic aberration is generally not serious. When using ABS color masterbatch, users must pay attention to this characteristic of ABS.