What are the three components that determine the performance of a coating?

March 23, 2023 Longchang Chemical

What are the three components that determine the performance of a coating?

Definition of paint

A coating is a material that has fluidity, forms a thin film after being applied to the surface of an object, dries and cures, and is firmly bonded to the surface of the object to protect it and add beauty and other special effects, forming a continuous coating film. As the definition says, the role of paint is: protection, aesthetics, special role.




The substrates of iron, plastic , cement, wood, etc. will be damaged by rusting, becoming brittle and decomposing due to the different environment they exist.


Coatings produce a continuous, strong coating film on the surface of an object, which protects and prolongs the life of the object in its environment. For example, the car, due to its primer electrophoretic paint coated with rust prevention function has been greatly improved, even after more than ten years, can not see the body rust .




Giving processing effects such as color, gloss, smoothness and pattern to the object, providing beauty, satisfaction and comfort, and improving the value of the object. In recent years, metal treatment for automobiles has become mainstream, and, new, glossy finish is popular and new products are being supplied. As you must know, the white pearl color, which has become quite popular recently as a special paint color style, sells for about 30,000 yen more than other painted color cars .


3、Special role


In addition to protection and aesthetics, the value of the object is enhanced by the special function of the paint. There are several types of paints with special functions.

Electrical and magnetic functions: electrical conductivity, electromagnetic wave shielding, wave absorption, prevention of electrical charging, insulation, etc.

Thermal functions: heat resistance, fire resistance, solar heat absorption, temperature indication, heat reflection, etc.

Optical functions: fluorescence, light storage, infrared reflection, etc.

Physical functions: prevent bottle cracking, prevent stickers, prevent condensation, etc.

Biological functions: anti-bacterial, anti-bacteria, anti-algae, anti-insect, etc.

The performance of paint is mainly determined by three parts: film performance, construction performance and environmental performance.


Film performance

The performance of paint film refers to the performance of paint film formed after coating.

(1) Appearance of paint film: It refers to whether the paint film is smooth, with or without particles, bubbles, shrinkage, blossoms, construction traces, etc.

2) Gloss: A parameter to measure the ability of the paint film to reflect light. Gloss is a very significant feature of the paint film, which has a great influence on the decorative performance of the paint; the paint with high gloss is easy to show the defects of the substrate, so the requirements for the flatness and roughness of the substrate are relatively high.

(3) Hardness: It refers to the resistance of the paint film to the invasion of foreign objects on its surface. The hardness of paint film is one of the important indicators of physical properties. Generally speaking, the hardness of the paint film is related to the composition of the paint and the degree of drying.

You can use the Chinese pencil as the standard for scoring and observe the damage of the paint film.

(4) Adhesion: It indicates the firmness of the paint film bonding to the substrate. Adhesion is a very important indicator of the paint film, poor adhesion, the paint film is easy to peel off. Commonly used to test by scribing method (1mm and 2mm drawer)

(5) Transparency: the clarity of the paint film to show the condition of the substrate (good transparency of the paint to make a strong sense of three-dimensional wood grain, dark panels require higher transparency)

6)Coverage power (solid color): indicates the ability of the solid color paint to cover the color of the substrate (paint with good coverage power can reduce the number of coats during construction).

(7) Yellowing resistance: the ability of the paint film to maintain the original color and luster is not easy to change color (light-colored panels for transparent process requires higher yellowing resistance)

(8) scratch resistance: hard scratch (scrape, rub, scratch the surface of the paint film after drying with moderate hardness of the same strength, observe the degree of damage), soft scratch (refers to print paper with moderate strength rubbing the surface of the paint film, observe the degree of damage)

(9) flexibility: in bending, holding around, twisting and be damaged or not, can recover or can not recover the performance.

(10) fullness: the coating gives a sense of flesh, is a more important performance of the top coat, and is generally measured in comparison.

(11) Feel: The lubricious feeling of touching on the paint film by hand after the paint film is actually dried.


Construction performance

Construction performance refers to the performance and construction parameters of the paint in the construction process.

1)Constructivity: It refers to the feel, paint splash, defoaming, etc. when roller coating and brush coating.

2)Coating volume: also called paint consumption, refers to the amount of paint consumed when painting a certain thickness on the substrate per unit area.

The factors affecting the coating amount are: the factors of the coating itself (viscosity, workability, etc.), the flatness and roughness of the substrate, the absorption ability of the substrate, the weather conditions, the management and construction level, the painting requirements, etc.

3) Drying time: surface dry (refers to the time required for the paint film surface to dry), finger pressure dry (thumb pressure on the paint surface does not leave finger pressure marks or damage the surface of the coating time), sanding dry (from the coating to sanding not sticky sandpaper for this period of time), solid dry (also known as hard dry time, refers to the time required for the basic drying of the paint film)

4)Re-coating time: refers to the time from when one coating is well applied to when the next coating starts to be applied.

5)Fillability: refers to the ability of primer to fill the wood eye, fillability is a relative performance, usually a comparison test, fillability is very much related to the amount of oil content of the primer’s body pigment, so fillability has a great relationship with transparency (good fillability of the primer is applied less times)

6) sandability: after the paint film dries, it is difficult to grind it into a flat surface with sandpaper (primer with good sandability is more convenient for construction)


Environmental performance

1)Triphenylene content: pure benzene is extremely hazardous grade, which is very harmful to human body and carcinogenic, and has been banned in the paint industry;

Toluene and xylene and other molecular structure containing benzene ring belongs to the benzene family, belongs to the moderate hazard solvent, as an important organic solvent, toluene and xylene are still used.

There are two kinds of benzene-free thinners advertised on the market: one is a thinner without pure benzene with toluene and xylene; the other is a thinner without tritylenes (benzene, toluene and xylene), and the benzene-free thinner in the strict sense is free of tritylenes.

(2) Free TDI: Free TDI, that is, toluene diisocyanate, exists with two-component polyurethane coating curing agent.

Toluene diisocyanate (TDI) has a strong irritating odor and is a strong irritant to the skin, eyes and respiratory tract. Long-term exposure or inhalation of high concentrations of TDI vapor can cause bronchitis, allergic asthma and other diseases.

(3) Heavy metals: The pollution of heavy metals such as lead and chromium in paint mainly comes from the color filler and some additives. Such as red pigment (lead oxide), chrome yellow pigment (lead chromate)

Soluble heavy metals such as lead, mercury and chromium are common toxic pollutants. Long-term skin contact can cause contact dermatitis or eczema, and excessive lead, mercury and chromium can cause serious harm to the human nervous and visceral systems.

(4) VOC: is the sum of volatile organic compounds, Volatile Organic Compounds for short.

Solvent-based paints contain a large amount of solvents and need to use more thinner for dilution during construction, which is a high VOC content in paint varieties.

The main impact on human body is to stimulate the eyes and respiratory tract, skin allergies, and in serious cases, headache, sore throat, fatigue and other symptoms, which endanger human health.


What is the difference between water-based and oil-based?

Water-based paint is a water-based diluent, organic solvent-free paint, does not contain benzene, toluene, xylene, formaldehyde, free TDI toxic heavy metals, non-toxic and non-irritating odor, harmless to humans, does not pollute the environment, can be used in: wood, metal, plastic, glass, building surfaces and other materials. So the following Longchang Chemical to explain the difference between water-based paint and oil-based paint, the method of differentiation, comparison, the characteristics of water-based paint and the advantages accounted for in the decoration.


The hardness of water-based paint is a major feature, it is manufactured with water-based acrylic or water-based polyurethane system and other advanced technology, the hardness is comparable to the H level pencil. But oil-based paint is the opposite, the paint applied on the hardness is poor;

2、Feel and fullness

From the feel can also be distinguished from water-based or oil-based, because water-based paint using hand wax technology, feel will be particularly full and comfortable, but you feel the oil-based paint when you feel the feel is not good;;

3、Abrasion resistance, yellowing resistance, durability

Because the use of film and self-crosslinking technology, water-based paint painted surface with hard, wear-resistant, flexible and other characteristics, and long-term use will not appear yellowing problems, but oil-based paint is not as wear-resistant as water-based paint, and in the effect of maintaining not so good.


How to distinguish between water-based paint and oil-based paint?

1、Smell the smell

To distinguish between water-based or oil-based, first from its smell, and water-based paint is naturally nothing, and in the water-based paint does not contain benzene, toluene, xylene, formaldehyde, while oil-based is the opposite, it contains the above substances, so its smell is very irritating, a smell to know;

2、Exclusion method

use the exclusion method also allows you to choose the paint you need faster, for example, solid wood, solid wood veneer furniture generally with water-based paint, if the board furniture is mostly with oil-based paint;;

3、Seek evidence

Product Instruction Manual” and “Inspection Report” is the evidence to distinguish between water-based and oil-based, you can ask to check when you buy, if water-based paint, generally in the coating column will be marked.

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