Summary of specific steps for plastic color matching

The setting items include colorant shape, color matching, colorant selection (including addition amount, colorant type selection), design formula, repeated color matching test, and color matching colorant selection including weather resistance, dispersibility, deformation, filterability, Mobility, heat sealability, safety, coloring costs.

1, first understand the sample requirements

(1) the type of plastic of the sample;

(2) the plastic use of the sample;

(3) Sample forming process.

According to the above three conditions, it can be understood that the colorants selected for the product need to meet the requirements (heat resistance, light resistance, weather resistance, migration resistance, safety). In addition, the color matching personnel are required to confirm the dosage form of the colorant required by the customer (pigment dry powder, masterbatch, sand, modified material), and confirm the coloring ratio (addition amount) required by the customer.

2, according to customer requirements for preliminary formulation design

(1) Selection of pigments. The colorant is selected depending on whether the sample is transparent, opaque or translucent.

(2) Comprehensive consideration of coloring costs. Cost is also a very important consideration, and the price of the pigment is as important as the performance of the pigment.

(3) Prepare a preliminary formula. After repeated research, the difference between the standard color sample and the reference is repeatedly compared from the aspects of hue, brightness, shading, etc., on the basis of which the colorant formulation of the reference substance is corrected, and a preliminary formula is prepared. In the absence of a reference, the color shade, hue, and brightness of the plastic product (sample) should be carefully analyzed to determine the color properties, and then the color scheme is based on the Munsell color system, and the formulation is formulated.

3, repeatedly adjust the sample as close as possible to the customer sample

At present, the plastic dispensing method adopted by various enterprises is actually a trial and error method, which is not very scientific, but it is still very recognized in the color matching of the plastic industry, and is widely used by most enterprises. The color matching personnel perform the physical coloring test according to the proposed preliminary formula, and compare the prepared colored sample with the standard color sample and the reference material to further adjust the coloring formula. The samples were then prepared according to the adjusted formula for comparison.

4, the comparison of colors

The comparison of the color of the sample and the sample provided by the customer is a very important part of the color matching. According to the customer sample production process to make samples comparison, film products are often compared by blown film method, injection products are compared by injection molding, and fiber products are compared by spinning method.

(1) The influence of the light source. The light source is preferably natural light when it is used. It is possible to use a standard light source box. Otherwise, comparing the color of two samples under some lights may cause the colors to look the same because of the "metamorphism" phenomenon, but under natural light. But there is a big color difference.

(2) The effect of thickness. Different thickness products give the human eye a different feeling; the thickness is smaller than the light transmission, and the color becomes lighter. Therefore, the color of the sample should be consistent with the thickness of the customer sample as much as possible.

(3) The influence of the surface state. Different surfaces have different light reflections. For example, on the same sample, the color of the matte surface on the high-gloss surface obviously gives people different feelings. On the same sample, the rough surface is smoother and darker, so the colorimetric When comparing, try to compare the parts with similar surface conditions.

(4) The influence of the resin. The same pigment is used in different resins. The color is different due to the different color and transparency of the resin. Therefore, the color matching should pay attention to the color matching of the resin provided by the customer to ensure the accuracy of the color, especially the modified material. Color matching needs more attention.

(5) Colorimetric judgment error.

The most common problem in the verification process is that the colorimetric judgment is wrong. The judgment error is mainly caused by lack of experience. Usually, it can only be practiced by constant practice and continuous enrichment of experience. Appropriate use of some instruments such as colorimeter can also be used. Helps make the right judgment.

5, metamerism

A pair of samples were made from different colorants. They are matched by a particular source when they are illuminated by a particular source. If the illumination changes, the object will no longer match. Metamerism is common and sometimes unpleasant, but metamerism makes it possible to match many different pigments. Toxic colorants can be replaced with non-toxic colorants. Expensive colorants can be replaced with inexpensive colorants to reduce cost. Due to the presence of metamerism, it is possible to use a different colorant to re-grant a recipe. The color combiner can assign the coordinates of an article in a color space to match their colors, even though they are made from different colorants. The only way to eliminate the conditional color matching of an object is to use the same colorant.