Solution to the color difference of blow molded products

Author: MULAN - Plastic Molding Manufacturer

Controlling raw materials is the key to solving the color difference of blow molded products. If all new materials are used in full and the parameter temperature is well controlled, the color difference of the blown product caused by raw materials is basically very small. If recycled materials are added, problems such as color value of the recycled materials and uneven stirring during the mixing process of the added amount will appear. There is a problem of color difference in blow molded products. If adding recycled materials in production, it is necessary to adjust the addition ratio and stirring time according to the performance of recycled materials to ensure uniform raw materials and reduce color difference of blow molded products. 1. The problem of raw materials and color masterbatch When using color masterbatch, strengthen the inspection of raw material warehousing; as much as possible, use the same manufacturer, same brand masterbatch and color masterbatch to produce the same product in blow molding. If it is necessary to change the color masterbatch manufacturer, do a small sample test, and only after meeting the standards can mass production begin. 2. The problem of uneven mixing of raw materials and color masterbatch Poor mixing of raw materials and masterbatches will also change the color of the product. After the raw materials and color masterbatch are evenly stirred, when the material is fed into the hopper through the lower suction, the color masterbatch is separated from the masterbatch due to electrostatic action, and is easily adsorbed on the wall of the hopper, which will inevitably cause changes in the amount of color masterbatch during the blow molding cycle, resulting in color difference . The most effective way is not to use the suction machine, but to use the hot air dryer, and use the method of manual feeding to prevent the color difference caused by the separation of the toner and the masterbatch. 3. The temperature of the barrel affects the color difference In the blow molding process, it is often encountered that the temperature of the barrel changes sharply due to a damaged heating ring or the heating control part is out of control for a long time, resulting in chromatic aberration. Generally, when the heating ring is damaged and fails, the chromatic aberration will be accompanied by uneven plasticization, and the uncontrolled long-term burning of the heating control part is often accompanied by gas spots, severe discoloration or even coking of the product. Therefore, the blow molding process needs to check the heating part frequently, and replace and repair it in time when the heating part is found to be damaged or out of control, so as to reduce the probability of such color difference. 4. Problems in production process adjustment When adjusting the blow molding process parameters in the production process, try not to change the blow molding temperature, back pressure, blow molding cycle and the amount of color masterbatch added. At the same time, it is necessary to observe the influence of the change of process parameters on the color.