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A problem that is more likely to occur when plastic granulation, according to the original formula production, there are color differences from time to time. Many people are strange, the same formula, before qualified, but this time the boot is not qualified, and even the difference is very big; Or running in the production process, it ran off, so the inevitable stop, check the problem, readjust the formula, and then boot.

If bad luck, it is estimated that a night or a few days on this, and ""no grain harvest"". So, today, let's talk about several reasons for color difference in the granulation process:

master color without careful testing, Production of granulation directly

This is the author's real experience of things, at that time, the company in order to reduce environmental pollution, reduce cleaning time, etc., decided to use color masterbatch instead of color powder, nylon modified granulation. The replacement of high concentration masterbatch in foreign R & D department after testing, the test results qualified.

Therefore, in the production process in accordance with the original toner ratio of the formula, according to the color master batch toner content to develop the proportion, so as to produce in the production line. The result, more painful, after dozens of boot test shutdown, the production of several tons of unqualified products, is still very different from the standard sample. Finally, had to give up.

(Many people may ask, why not stop and test deploy on the trial line? Among the reasons, the author is not willing to disclose too much, but things are happening)

Therefore, it is recommended that if the high concentration of color masterbatch instead of color powder granulation. If you are not 100% confident, please first test in the test line, after the test line qualified, and then in the production line for production, sometimes in the test line qualified, the production line is not necessarily qualified, but also need to be deployed again. Therefore, careful color testing is a more effective way to reduce production costs and reduce waste.

mother color match the problems with the resin

Due to the improper choice of the carrier of the masterbatch, or the manufacturer will change the variety of resin. Different grades of resin its density and melting index will be different, so the performance of the resin will be different, and the compatibility of the master will be different, resulting in color change, generally speaking, as long as its density and melting index is not very different, then the color difference is not too big, you can adjust the amount of color master to more positive color.

Metering is not accurate when used, Pigment, pigment too little or too much

toner heat-resistant

due to improper temperature machine, especially on the high side, the pigment in the machine for a long time, cause the toner burn, Resulting in the color of the difference. Generally, the heat resistance of inorganic pigments is relatively good, which can basically meet the requirements of plastic processing, and the heat resistance of organic pigments is relatively poor. Usually the higher the temperature, the shorter the heat resistance time.

so the machine at high temperature, masterbatch or pigments in the machine for a long time, cause the toner is burnt, resulting in color.

the influence of the production process

drying material link

ABS, PA, PC and other raw materials need to dry water before color matching, and baking time is too long, baking temperature is too high, will make the raw material base color baking yellow or discoloration and lead to color difference.

mixing materials links

in the process of mixing materials, material cylinder is not clean, will be mixed with other colors and color difference; Mixing time is not enough will be mixed with other colors and produce color difference; Mixing time is not enough or too much material leads to uneven mixing will also produce color difference.

charging links

refueling production must clean cylinder, and drying and then continue production.

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