Plastic Color Masterbatch Injection molding is one of the most common forms of molding in the formation of plastic products. In the face of colorful injection molded parts, we will think about how to make colorful, colorless products? People who are engaged in the production of color matching in injection molding will have the feeling that a product sometimes changes to a color in a few days, and even a variety of color deviations occur within a day. So, what factors affect the color stability of the molded parts?
1.Raw materials and their treatment
Raw materials include plastic raw materials, toners, masterbatches, and the like. Due to the different background colors of each raw material, the same color of the molded parts of the toner will be different. Sometimes the same supplier, the batch number is different, the background color will be somewhat biased, so the product with high color deviation requirements, even to control whether the background color of each batch is consistent. In addition to the batch of plastic raw materials, batch stability of raw materials such as toner pigments or masterbatches must also be concerned.
The raw material will have a humidity effect, and the humidity will be too large, which will cause the toner to stick and not spread. The temperature effect needs to be considered in the processing of the material. Plastic Color Masterbatch Each material and pigment has its temperature and time range of the material.Plastic Color Masterbatch Colorants are fundamental to color, so they are listed separately. There are currently many colorant products and their performance varies. If the quality of the toner is too bad, it is not heat-resistant, or if the toner used in the wrong material is not suitable, the color will be unstable. The colorant material is too coarse, and the concentration level of the color masterbatch is too low. If it exceeds this range, the color of the molded part will change. If the feeding time is small, the color that is more affected by the temperature will be unstable, such as the color containing the fluorescent material or the light-colored injection molded part. Therefore, for temperature-sensitive plastics, it is best not to dip or use the bottom temperature to dip the material. Another point is that in the hopper, due to the influence of hot air, the toner is locally concentrated, resulting in a deeper and deeper color. The injection molded parts with more pockmarks may have excessive pitting. At this time, it is necessary to add some diffusion oil to make the toner firmly adhere to the raw material.
The return material will be used in the production, and the change in the amount of water returning will also affect the color of the injection molded parts, especially the light-colored injection molded parts. The plastic crystal form also needs to be considered, and the colorant affects the crystallinity, which affects the performance, and also affects the coloring stability.
2.coloring agent: toner, masterbatch, etc.
Plastic Color Masterbatch Colorants are fundamental to color, so they are listed separately. There are currently many colorant products and their performance varies. If the quality of the toner is too bad, it is not heat-resistant, or if the toner used in the wrong material is not suitable, the color will be unstable. The colorant material is too coarse, and the concentration level of the color masterbatch is too low.
3, molding conditions
Temperature is a key factor in molding and has a significant impact on color stability. The temperature of the injection molding machine is unstable, high and low, and the color will be unstable. Usually, the temperature difference is about 10 °C, the color deviation of the injection molded parts can be seen. When the color of the injection molded part is not very different from the sample, it should be solved by adjusting the temperature. By adjusting the temperature of the normal injection molding temperature of the raw material by 5 to 15 ° C up and down, an obvious effect of improving the color deviation has been received. In most cases, the temperature rises, the dark parts will become lighter, and the white parts will be yellowish. Conversely, the temperature decreases and the color becomes darker, and white is whiter. However, there are also individual colors that are opposite or elusive, such as fluorescent colors that are hard to find. If the color deviation is too large, it is difficult to solve by adjusting the temperature. At this time, it is not too late to notify the color matching person to perform color matching, which can reduce the number of times of coloring. However, it is important to adjust the color to be used in the injection molding temperature required to produce the product. Otherwise, the color deviation will occur after the production is different from the color temperature.
Since temperature has a large influence on color, it is also necessary to pay attention to controlling the temperature during production. Once the color has been determined, the temperature range should be kept within plus or minus 5 degrees. Light color and other materials that are affected by temperature, even the temperature and time of the material should not be too high and too long, otherwise it will have an unstable effect on the color, which is fluorescent color and purple. . Therefore, if it is necessary to solve the water vapor problem for a long time, it is best to go to the color after the completion of the material.
(2) Other molding conditions
In addition to temperature, attention should also be paid to the amount of material, the production cycle, and the like. The production cycle is unstable, the time is stopped when the time is open, and the back pressure is too large to cause the running temperature, which will change the color. The toner and raw materials must be mixed according to the mixing process requirements. Otherwise, the mixing time is insufficient, the feeding method or the order is not equal, which may result in uneven toner. Molding conditions ensure that the colorant and plastic are fully mixed and plasticized without affecting the stability of the colorant and the plastic itself.
The pouring system of injection molding needs to be reasonably designed according to the shape of the parts, and the position of the gate has an influence on the filling of the plastic, making some parts of the parts produce color difference, which should be modified when necessary.