The Influence of Pigments on Chromatic Aberration of Injection Molding Products

I. What is chromatic aberration?

Chromatic aberration literally refers to the difference in color that is visible to the observer. It's quick, cheap and easy to measure chromatic aberration with naked eyes, but it's not reliable.

There are three kinds of human visions: rod photoreceptor cell vision, which is more sensitive at night (scotopic vision); cone cell vision, which is more sensitive during the day (photopic vision); mesopic vision, which judges the aberration by switching the scotopic vision and photopic vision.

The chromatic aberration that the observer can distinguish is also related to the psychological and physiological factors of the observer. It is a major scientific advance to describe chromatic aberration with data. The use of chromatic aberration instrument for chromatic aberration test can avoid human and environmental factors, resulting in misjudgment.

In 1976, International Commission on Illumination practiced CLE*L*Α*B color system, which uses specific data to indicate the differences of two color in color perception.

II. The chromatic aberration of plastic injection moulding parts

The chromatic aberration is a common defect in injection moulding. It is common to scrap injection products in batches due to the chromatic aberration of fittings. There are many factors affecting chromatic aberration, including raw material resin, color masterbatch, injection moulding process, injection moulding machine, injection moulding die, etc. Because it involves a wide range of aspects, chromatic aberration control technology is also recognized as a difficult technology to master in injection moulding.

In the actual production process, the masterbatch is one of the most important factors affecting chromatic aberration, and among which the heat resistance of colorant in masterbatch is an important factor affecting chromatic aberration.

Chemical Industrial Press recently published a new book named Plastic Colouring Agent-Variety, Performance and Application, which is welcomed by the masterbatch industry. Many enterprises regard it as a plastic coloring reference book and prepare one for every technical personnel. For this reason, Chen Xinhua, the author of the book, was invited to attend the fourth China Injection moulding Industry Conference in 2016. From the perspective of colorants, he analyzed the influence of chromatic aberration on injection moulded products. He said that the influence of pigment heat resistance on chromatic aberration is not only determined by the chemical structure, but also by the size of the pigment particle size, crystal shape, and the amount of additives.