【Coating Society Information】Commonly used technical parameters and calculation methods for paint coating

01 The volume solids of the paint The volume solids of the paint is the volume ratio of the non-volatile components in the paint to the liquid paint.

This is a very important concept.
After the solvent in the liquid coating evaporates, what really stays on the surface of the coated object and becomes the paint film is the non-volatile content in the coating, that is, the solid content.

Example: For a paint product, the measured wet film thickness is 200um and the dry film thickness is 80um.
Calculate the volume solid content: volume solid content = dry film thickness/wet film thickness = 80/200 = 40% The volume solids is 40%.

02Dry film thickness and wet film thickness The thickness of the dry film is usually specified in the coating contract.

The measurement of the wet film thickness can help determine how thick a coating layer must be applied to achieve the specified dry film thickness.

The measurement of the wet film is helpful to find the difference in the thickness of each construction coating in time, so as to correct it.

Knowing the specified dry film thickness, check the volume solid content of related products, and calculate the corresponding wet film thickness, which can be calculated according to the following formula.

Example: The volume solid content of epoxy general primer is 57%, and when the dry film thickness reaches 50 microns, calculate the wet film thickness to meet the requirements.

Wet film thickness=dry film thickness/volume solids=50/57=87.
7≈90um.

03 The wet film thickness after dilution In actual construction, it is often necessary to add a thinner to the coating.
The use of thinner increases the total volume, but does not increase the volume solid content.

For example, if you add 25% thinner to dilute the paint, all you need is to add 25% to the formula, calculate the wet film thickness of the diluted paint, and calculate it according to the following formula: Example: paint with a solid content of 50%, diluted After 20%, a dry film with a thickness of 100um should be applied.

In order to ensure that the specified dry film thickness is achieved, what should be the wet film thickness applied by the paint? 04Theoretical coating rate is a key factor in calculating the cost and coating consumption for owners and contractors.
The theoretical coating rate means that the coating is applied on a smooth surface without loss.
The area that can be coated per 1L is M2, unit It is M2/L. According to this definition, we can get the following calculation formula for the coating rate of liquid paint under any given dry film thickness (expressed in square meters per liter): For example: the volume solid content of inorganic zinc-rich primer is 63% , The dry film thickness is specified as 75um, and the theoretical coating rate is calculated: 05 Actual coating rate The actual coating rate is the percentage of the theoretical coating rate minus the loss.
The calculation formula is as follows: If the theoretical coating rate has been calculated, It can also estimate the loss percentage of the coating, such as 40% loss, then according to the thickness of the previous inorganic zinc-rich primer of 75 microns, the theoretical coating rate: actual coating rate = theoretical coating rate (1-40%) = 8.
4 (1-40%) =5.
04m2/L In fact, this loss percentage is uncertain, because the actual construction is affected by many factors, construction methods, working techniques, the shape of the coated object, and the roughness of the surface.
Degree, working environment and distribution degree of paint film, etc.

06 Actual amount of paint The actual amount of paint is obtained on the basis of the actual coating rate, which can be calculated according to the following formula: (1-loss%) in the above formula is the loss factor.

Example: There is a storage tank with an inner wall of 2000M2, spraying 2 coats of phenolic epoxy paint with a volume solid content of 76%, each of 150 microns, and the estimated loss is 40%.
Calculate how many L of phenolic epoxy paint should be used.

Then the total of 2 coatings needs to be calculated by 658×2=1316L07 coating price.
When quoting the coating project, the coating company often uses different coating products, or even the same coating products but different volume content products, and the quotation is The price is also different.

Can it be said that the low price is the low cost? Facts have proved that even if the unit price of a product with a high volume content is high, the unit price per square meter is often lower than that of a product with a low price and a low volume content.

[Picture] Example: A structure requires epoxy primer with a dry film thickness of 120 microns.
The solid content of traditional epoxy primer is 50%.
If the unit price is 32 yuan/L, high solid content modified epoxy The solid content of the primer is 80%.
If the unit price is 49 yuan/L, it can be seen that the unit price per square meter is lower if the modified epoxy primer with high solid content is used. Foreign coating companies adopt the concept of L in coating formulation design, technical data calculation and packaging specifications.
Domestic companies often use KG to calculate and package technical data.
The introduction of the concept of quality can facilitate calculations.
Related data products The density can be obtained from the manufacturer's data sheet.

Price per liter ÷ density = price per kilogram Example: a certain epoxy iron-removing intermediate paint, the density is 1.
8KG/L, and the price is 48.
8 yuan/L, then the price per kilogram of the epoxy iron-removing intermediate paint is 48.
8÷1.
8= 27.
11 yuan/KG Since the density of paint is usually higher than 1.
0KG/L, unless the thinner of the solvent is sometimes lower than 1.
0KG/L, the price per liter is larger than the unit price per KG.