Toning tips for powder coatings to share!

As an important part of colored powder coatings, pigments mainly play a role in covering, decorating and protecting the object being coated.

According to the structural design of the painted workpiece, colored powder coatings can show the hidden style and cultural heritage of the workpiece, giving people a beautiful feeling, and the coating film has different properties such as UV resistance, weather resistance, water resistance, alkali resistance, and acid resistance.

Degree of influence.

The current powder coating manufacturers generally use manual color matching and computer color matching, and manual color matching is usually the main way.

Therefore, this article summarizes some color matching techniques .

1.

Basics of Color Science

Color is a kind of visual angle nerve sensation caused by the stimulation of radiant energy of a certain wavelength and intensity by the human eye, although the color varies greatly.

But the most basic colors are only three basic colors: red, yellow, and blue, which are usually called three primary colors.

The two primary colors are mixed with each other in equal amounts to form a secondary color (intermediate color), and the secondary color and the primary color are mixed with each other in equal amounts.
Recolor, as shown in the figure:

Mixing the three primary colors of red, yellow, and blue in equal amounts will turn it into black.

As a powder paint colorist, you must master these basic knowledge.

Generally, a pigment is determined by the three parameters of hue, saturation, and lightness, which are also called the three elements of color.

Hue refers to the color difference between different colors such as red, yellow, and blue, which determines the spectral composition of the light source and the ratio of the various wavelength radiation reflected (or transmitted) on the surface of the object to the human eye.

Brightness (also known as brightness) refers to the difference between the lightness and darkness of the color.
It is the light perception of the human eye on the object.
Generally, the visual angle of the hand is affected by the past experience.
The higher the object’s reflectivity to light, the more its brightness.
high.

Saturation (also known as purity) refers to the degree of color saturation, sometimes also called chroma, that is, the purity of the color displayed on the basis of hue.
The monochromatic light of visible light is the most saturated color.

When these pigments are mixed with more white light, the more they become more unsaturated, the less selective the reflection of light waves, and the stronger the selectivity to light waves, the more saturated.

A single color is a pure color without adding other colors, and other colors are added to become secondary colors or multiple colors.
When two coated objects of the same color are irradiated by different lights or sunlight, the two objects show different colors and shades.
, This is the nature of brightness, and the color of a certain hue has strengths and weaknesses, which is the difference in saturation.

Toning is the knowledge that every technician must have.
The three elements of color can be used to distinguish the difference of colored powder coatings, that is, only when the three characteristic values ​​of hue, brightness and saturation of the two colors are the same, the two Only when the two colors are exactly the same, if one of the parameters is not equal, the two colors are inconsistent.

2.

Toning skills of powder coatings

2.

1 Pigments commonly used in powder coating toning

Pigments used in powder coatings can usually be classified according to different methods such as production method, composition structure, function, etc.
:

According to the production method, the production method can be divided into natural pigments and synthetic pigments.
Among natural pigments, such as ingot blue, there are less natural pigments used in powder coatings, while synthetic pigments include titanium dioxide, iron oxide series pigments, and phthalates.
Cyanine series, azo pigments, polycyclic pigments, etc.

Functional distinction, according to the function in powder coatings, it can be divided into coloring pigments, extender pigments (also called fillers), anti-rust pigments, conductive pigments, etc.
For most functional powder coatings, the application of functional fillers is very important.

According to the chemical composition structure, the pigments for powder coatings can be divided into inorganic and organic according to the chemical composition structure.
Among the inorganic pigments, titanium dioxide, zinc oxide, iron oxide series, molybdenum chromium series, aluminum pigments, metal pigments, etc.
, and organic pigments Such as phthalocyanine series, azo series, polycyclic pigments, etc.

Manufacturers permitted by the conditions can be divided into more detailed charts, or because of the needs of the manufacturer's internal coding, examples can be as follows:

2.

2 Hue in the toning process of powder coatings

The pigments used in powder coatings show different hues due to different factors such as the chemical composition, crystal structure, surface state, particle size, process and equipment of the pigment.

For example, carbon black is the most widely used pigment in powder coatings.

When its particle size decreases or the surface increases, the blackness of carbon black increases, absorbs more light, reflects less, and makes people feel darker.

Some businesses may also encounter the problem that black is not “black” no matter how it is adjusted, that is, the hue problem!

It is very important to understand the color relative to powder paint toning.

For example, if the adjustment is exactly the same as the model, it is set to 10 (which means that you are very satisfied, and you don't need to add any more colorants).

Then it is easier for us to do the process from 0 to 9, but from 9-10, there is a lot of difficulty.

At the end of the adjustment, no paint is needed, and only the hue is missing.

In addition, both domestic and foreign pigments have different degrees of hue batch difference, and the powder coating production process is not easy to control, so general customers are also allowed to have a certain color difference range.

2.
3 The gorgeousness of the color sample

Inorganic pigments usually have good gloss and color retention and low cost, but the pigments are darker (that is, not bright) and have low tinting power, while organic pigments usually exhibit bright colors, high tinting power, high cost, and poor gloss and color retention.

Of course, some large-scale organic pigments have lightfastness above level 7 (lightfastness 1-8, level 8 is the highest level), weather resistance is above level 4 (weatherability 1-5, level 5 is the highest level), but the price is extremely high.
Expensive, so the price and cost of powder made of this kind of pigment are also high.

According to the gorgeousness of the color sample, combined with the price cost, a standard color formula is debugged.

3.
Computerized and manual toning

3.
1 Computerized color grading

The use of modern tinting technology to produce colored powder coatings is the direction of current international development.
Computer color matching must meet the following conditions:

The hardware, spectrophotometer, computer, software, and color matching program of the entire color matching system should be produced by one company;

In the process of establishing the basic data of computer color matching, the color of the target color is measured with a spectrophotometer, converted into an electrical signal by the computer, and compared with the original stored basic data, the paint formula close to the target hue is calculated.

3.
2 Artificial color matching

Due to the limitations of computer color measurement of powder coatings, artificial color matching is particularly important nowadays.

Conditional manufacturers can do some databases, conduct a single-color plate system experiment on a pigment, and make three color levels for a given pigment: a high-saturation color plate with little or no white pigment; add a large amount of white pigment to dilute Light-colored swatches; dark swatches with black paint.

The establishment of the database needs to obtain the following relevant information: the coloring power and hiding power of the pigment, and the degree of discoloration caused by temperature and time during the baking process.
The final result should be recorded in detail (such as curing conditions, use and requirements) , Colorimetric conditions, and color difference range information).

With this information, we have a relatively sufficient grasp of the properties of the pigment.

Due to the limitations of instrument color matching, the effect of instrument color matching is ultimately determined by visual inspection, so manual color matching is still the main color matching method in the recent period.

4.
Conclusion

In recent years, with the continuous expansion of the application fields of high-performance powder coatings, different coloring styles have also shown a diversified trend, embellishing a beautiful space for people’s lives.
Powder coating formulators should focus on different colors when designing colors or matching pigments.
Color selection under different conditions, different conditions and requirements, using a variety of methods and means, to be consistent with the sample, to achieve a more perfect color!