Custom Color for Custom Plastic Injection Molded Parts

Do aesthetics matter in your custom injection molding project? For many projects, the parts we make are internal pieces to a larger product or a part where function matters much more than appearance. In some cases however, aesthetics matter more and our customers want to manipulate the color of their plastic for their injection molding project. This is just another reason to love plastic engineering. We have the capacity to manipulate color so that we can perfect the aesthetics of your project, tailored directly to your vision.

Picture of red, blue, and yellow plastic resin pellets

There are a few different ways to add color to plastic during the injection molding process. Which way your engineer chooses will be based on the plastic material choice and the design and functionality of the finished product.

Solvent Coloring

This method is performed by the plastic injection molders themselves, not the resin supplier. It involves mixing a pigmented oil with a solvent which is then sprayed over the resin pellets before processing. This method proves a little difficult to control the pigment to plastic ratio.

Dry Pigment Mixing

Similar to solvent coloring, dry pigment mixing requires the injection molding operators to add a dry pigment to the resin batch at 2% pigment to volume. In this method, some of the dry pigment will naturally stick to the sides of the hopper making the ability to control the finished pigment less precise.


picture of red, orange, green, and pink plastic resin pellets

Unlike solvent coloring and dry pigment mixing, masterbatching is completed by the resin supplier. These colors can still be customized, and also come in standard colors. However, these resins are typically heavily pigmented and are not ready to be molded as-is. They still will be added to the resin in the hopper, before processing. Typically this pigmentation process is only used on larger productions.

Compounded Colors

Ready to process and made by the resin supplier, the compounded color or “pre-mixed” method certainly requires the least amount of work on the plastic injection molders end. Still not the optimal choice for small batch projects, however this is easier for quicker production turnaround time.

6 thoughts on “Custom Color for Custom Plastic Injection Molded Parts”

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