A common issue during plastic granulation is the occasional color difference that occurs based on the original formula. Many people are puzzled that the same formula, which was previously qualified, is now unqualified when turned on, and there is even a significant difference; Or running during the production process, it may deviate and inevitably shut down, check for problems, readjust the formula, and then restart. If you're not lucky, you might end up with this one night or a few days and 'no harvest' at all

  【Without careful color testing, the color masterbatch is directly produced into granules】

  Case: A certain enterprise company uses color masterbatch instead of color powder for nylon modified granulation. The replaced high concentration color masterbatch has been tested by the R&D department and the test results are qualified. Therefore, in the production process, according to the formula of the original color powder ratio, the ratio is formulated based on the content of the color masterbatch color powder, and then produced on the production line. The result was quite painful. After dozens of startup tests and shutdowns, several tons of unqualified products were produced, but they still differed greatly from the standard samples. In the end, I had to give up.

  因此：若用高浓度色母取代色粉造粒时。如果没有百分百的自信，请先在测试线进行测试，在测试线合格之后，再在生产线进行生产，有的时候在测试线合格，生产线都不一定合格，还需要再次调配。所以认真试色对于降低生产成本，减少浪费是一种比较有效的方法。

  【There are issues with the matching between colorants and resins】

  Due to improper selection of colorants or arbitrary changes in resin varieties by manufacturers. The density and melt index of different grades of resin may vary, resulting in differences in resin performance and compatibility with colorants, leading to color changes. Generally speaking, as long as the density and melt index are not significantly different, the color difference will not be too large, and the amount of colorants can be adjusted to correct the color.

  【Inaccurate measurement during use, excessive or insufficient amount of colorants and pigments】

 The phenomenon of domestic enterprises, especially small and medium-sized enterprises, arbitrarily measuring exists in large numbers. When weighing, they make mistakes in proportion, weight, and variety, resulting in the color of the produced masterbatch being different from the standard. These are all low-level mistakes that can be overcome with diligence. The higher the precision, the better the accuracy, which can also reduce the occurrence of non-conforming products to a certain extent.

  【Color powder heat resistance】

  The temperature of the granulator equipment may be improper, especially high, and the color masterbatch may stay in the machine for too long, causing the color powder to burn out and resulting in color differences. Generally, inorganic pigments have good heat resistance and can basically meet the requirements of plastic processing, while organic pigments have poor heat resistance. Usually, the higher the temperature, the shorter the heat resistance time. So, when the machine temperature is too high, the color masterbatch or color powder stays in the machine for too long, causing the color powder to burn off and resulting in color difference.

【The impact of the production process】

  1. Drying process

  ABS, PA, PC and other raw materials need to be dried for moisture before color matching. Prolonged baking time and high baking temperature can cause the base color of the raw materials to turn yellow or discolor, resulting in color difference.

 2. Mixing process

 During the mixing process, if the material tank is not cleaned thoroughly, other colors may mix and cause color differences; Insufficient mixing time may result in color differences due to the mixing of other colors; Insufficient mixing time or excessive material can result in uneven mixing and color deviation.

  3. Feeding process

  The replacement production must clean the material cylinder thoroughly and dry it before continuing production.

  What are the reasons for color difference waste in plastic coloring and granulation production? Pay attention to the above aspects, which can greatly reduce the waste of resources!