A wide variety of colorants are available in shade, cost, thermal stability, light stability and grade.
It is essential to remember that color is subjective.
It is not possible to eliminate the subjectivity with spectrophotometer.
The subjective parameters:
The light source
The part finish
The type of polymer
The configuration of the part
The non-subjective parameters:
The base resin
For example: if you tried to use the same color concentrate for a homopolymer polypropylene and co-polymer polypropylene, you are not likely to achieve the same color.
Easy To Overlook Variable:
Part gloss: The more gloss the darker the color will appear
Reference Standards (masters) Do we all have the same standard? How are they stored? They should be kept in a dark places, as color will fade with time.
Have you changed your base resin?
Melt temperature: Is the mold in a different machine than previously used? Different screw geometry will produce a different heat profile.
COLOR IS WHAT WE SEE, NOT WHAT WE MEASURE!
One must supply all the necessary information and materials in order to successfully match your color and processing requirements.
The specific type, grade and manufacturer of the polymer to be used.
A good standard (e.g. existing color concentrate vs. a leaf).
Your manufacturing process: (e.g. Injection blow molding, hot runner mold, temperature inside your barrel).
The end product: (Indoor/outdoor use, FDA, light exposure, bottles etc…).
Every pigment and dye will have different heat parameters, light fastness, price tag and ability to make your manufacturing process and end product a great success.
On the other hand not enough information can make color the “necessary evil”.
Always provide as much information as possible.
It is our aim to incorporate the correct processing and additive aids to simplify your manufacturing needs.
It all starts at the beginning of a new project. “The Design Stage”.
The initial match may have been a pantone number (paper), a painted part, fabric or a different grade of plastic than you are using. When there is a problem, the solution is to COMMUNICATE. We must all work together to understand and resolve the issue.
There are three major classes of problems:
Metamerism when a color looks different under different light sources. When we match the color using two different types of resin, we experience metamerism as well. It is not possible to do an exact match (e.g. A GPPS standard to a TPE part.) These have different textures making is impossible to achieve a 100% perfect match.
When light hits the surface of the part, the angle of refraction is different for each family of plastic. Consequently, the human eye will see the difference.
Some colors will nucleate and the cycle time can be shortened.
Some colors will require different heating band setting profiles due to heat sensitive pigments. This is normal.
Some color will cause shrinkage. warpage, plate-out and blanching. This will require a rematch in order to reformulate by using pigments and additives to prevent these problems.
It is not possible to avoid the reduction of mechanical properties of a colored part to a part molded with natural resin.
Color is a contaminant and will reduce the mechanical properties differently.
The resolution of most color problems is dependent on communication with everyone involved.
Our laboratories custom match colorant systems and additive compositions designed specifically for your application.
: Learn More
If you have any questions or comments, please contact us.
ISO 9001:2008 certified