The Basis For Setting The Cooling Time In Injection Molding In injection production, the cooling time of plastic injection molding parts accounts for about 80%
9 Common Problems of Color Masterbatch
Common problems of color masterbatch
Problem 1: Under sunlight, there are streaks of pigment in the product.
This question needs to be considered from two aspects: the plastic physical and mechanical properties and the plastic molding process:
Influence of plastic physical and mechanical properties:
- 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 haven’ta certain amount of back pressure, and the mixing effect of the screw is not good.
- The dispersion of the color masterbatch or the resin plasticization is not good.
The process can be adjusted as follows:
- Increase the temperature of the mixing cavitypart which is close to the blanking port slightly.
- 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 we shouldcontact the masterbatch manufacturer to solve it.
Problem 2: After using some kind of color masterbatch, the product appears to be more susceptible to cracking.
This may be due to poor diffusion and mutual solubility caused by the poor-quality dispersant or auxiliary selected by the manufacturer. And that affects the physical and mechanical properties of the product.
Problem 3: After using the color masterbatch according to the ratio on the manual, the color is too dark or too light.
Although the problem is simple, there are still many possibilities, specifically:
- The color masterbatch has not been tested carefully, and the pigment is too little or too much.
- The measurement is inaccurate during use.
- There is a problem with the matching of color masterbatch and resin, which may be caused by theimproperly selected carrier of color masterbatch. Or maybe because the manufacturer change the resin variety at will.
- The temperature of the machine is improper, and the color masterbatch stays in the machine for too long.
First, check whether the resin variety matches the color masterbatch and whether the measurement is accurate.
Then, adjust the machine temperature and speed. If there are still problems, contact the masterbatch manufacturer.
Problem 4: Under the same conditions, the color of the products injected by different injection molding machines is different.
It is often caused by the injection molding machine. Different injection molding machines have different mechanical conditions. And the differences 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. It makes the dispersion state of the color masterbatch in the barrel different.
Problem 5: Using another brand of resin, the color has changed.
The density and melt index of different brands of resin will be different, so the performance of the resin will be different. Besides, the compatibility with the color masterbatch will also be different. All the above situation will cause color change. Generally speaking, as long as the density and melt index are not much different, the difference in color can’t be too much. You can correct the color by adjusting the amount of color masterbatch.
Problem 6: Does the migration of pigments during the storage of the color masterbatch affect the quality of the product?
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 the color masterbatch is injected into the product, the pigment is in the normal color concentration in the product.
Problem 7: Some injection products have poor gloss.
There are many possibilities:
- The nozzle temperature of the injection molding machine is too low
- The mold finish of the injection molding machine is not good
- The molding cycle of the product is too long
- There is too much titanium dioxide in the color masterbatch
- The dispersion of the color masterbatch is not good.
Problem 8: After a period of time, some plastic products will fade.
The basic pigments used by manufacturers are of poor quality and drift.
Problem 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. However, this chromatic aberration is generally not serious. When using ABS color masterbatch, users must pay attention to this characteristic of ABS.