The raw material granulate granules are supplied in a wide variety of types, colors, and designs. In order to influence properties or color, the producer often uses liquid and/or powder additives that are added to the plastic.
Sometimes the base material does not have the desired properties or color. Masterbatches are used to obtain the correct properties. In this case, a masterbatch is granulate that has been mixed with a high concentration of dye in a special company. By mixing the masterbatch in the right proportion with the basic raw material, a plastic injection molded product with the right color is created. In addition, various additives can also be added using these masterbatches. Examples of this are:
• Additives that provide protection against UV radiation/discoloration
• Fire-retardant additives
• Additives to improve the impact resistance of basic raw materials
• Blowing agents to increase the volume of the end product
• Binding resins to make plastics adhere better to other plastics
• Additives to make plastics less static
How long should the plastic product remain colorfast and lightfast?
The color fastness and light fastness are important for master batches. Lightfastness or lightfastness is the property of a dye that indicates the extent to which the dye is influenced by the influence of sunlight in particular. In other words, lightfastness is the ability to resist color changes when exposed to light. This is determined using the so-called blue wool standard. This standard ranges from 0 to 8, where 0 is very bad and 8 is very good.
Color fastness is the property of a dye or a material containing a dye to retain its original shade or intensity. Colorfastness refers primarily to the ability not to run or fade, which is usually the result of cleaning or exposure to light.
The required color and light fastness is mainly determined by the desired lifespan of the product, as well as the application and the environment in which it is used.
Dosing and mixing
A special dosing and mixing device is used to color or mix plastic granulate with a masterbatch. There are two methods of getting the right mixing ratio with these devices. The first is through gravimetric dosing, where the device first weighs the components. The device then ensures mixing of the exact weighed parts. With volumetric dosing, the device doses the various components by volume. This type of device first doses exactly the amount of dye and base material. The dye and the basic raw material are then intensively mixed in the granulate funnel.
Liquid masterbatches
It is also possible to use liquid color additives during the injection molding process. Liquid additives can be added to the process with great precision with special dosing equipment. The advantage of this is that you can quickly change colors and dose very accurately.
