Controlling raw materials is the key to solving the color difference of blow molded products. If the full amount of new materials is used to control the parameter temperature, the color difference of blow mould products caused by the raw materials is basically unlikely. If the recycled materials are added, problems such as the color value of the recycled materials and the uneven stirring during the adding 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 mould products.
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 mould. 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.
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 easy to be adsorbed on the wall of the hopper. Chromatic aberration occurs. The 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.
In the blow mould 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 mould 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.
When adjusting the blow mould process parameters in the production process, try not to change the blow mould temperature, back pressure, blow mould 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 of blow mould products.