Explanation of some common terms in color datasheets
In this article, we will explain some of the technical terms found in paint datasheets. Understanding these concepts will not only help you better understand the datasheet data, but will also help you select the right product and apply the paint correctly.
1-Appearance classification of drying surfaces
1.1 Surface drying
According to ISO 1517, surface drying of paint occurs when dust cannot adhere to the painted surface.
2.1 Tactile dryness
Tactile drying is when the paint does not sink if we apply slight pressure to the surface of the paint; in fact, it should not have any elasticity.
3.1 Portable drying
It is when the paint film has hardened enough that it can be carefully picked up and carried.
4.1 Drying Repaintable
It is the time after which the next coat of paint can be applied to the surface without the layers mixing together.
These parameters are measured at a temperature of 20 ° C (68 ° F), it is obvious that with increasing temperature the drying process is accelerated and this time is reduced, and vice versa, with decreasing temperature this time is increased. If the maximum repainting time has elapsed, the desired layer must be sufficiently roughened in order to ensure adhesion of the next layer. Also, if the painting process is carried out in very polluted environmental conditions, it is better to clean the surface of contamination with methods such as high-pressure water washing before repainting.
5.1 Complete hardening
Complete hardening occurs when the solvent evaporation process (in air-dry paints) is complete and the chemical reactions between the air and the paint film (in oxidative paints) and in two-component paints the chemical reaction between the various paint components is complete and the final dry film is obtained. For two-component paints, the final hardening time[6] is usually stated at 20°C (68°F) and, as previously mentioned, increasing the temperature shortens this time, so that for two-component paints, the hardening time is usually halved for every 10°C increase, and doubled for a similar decrease in temperature.÷
2- Some definitions and parameters specific to color
1.2 Transparency of the final film
The appearance and transparency of the paint film are divided into the following five categories. These data are collected for the dry paint film and a light incidence angle of 60 degrees (in accordance with ASTM D523-67).
Classification of paint films based on transparency
2.2 Wet film thickness
The thickness of the paint film immediately after application to the surface is called the wet film thickness. There are operational methods for measuring the wet paint film, which are mentioned in the literature related to paint application inspection.2.2 Dry film thickness
After the paint has completely dried, only a portion of the original volume of paint applied remains on the surface. The dry film thickness is the amount of paint remaining after the paint has completely dried. Methods for measuring this parameter are described in the section on paint application inspection.2-2% solids
This parameter is defined as volumetric solids and mass solids and represents the percentage by volume (mass) of paint that remains on the surface after drying. Volumetric solids are calculated according to the following equation:
In this case, VS% represents the volume solids percentage.
Paints can also be classified into four categories based on their volume solids content as follows:
Color classification based on volume solids percentage
3- Specific weight
Specific gravity is the mass of a unit volume of a substance, which is expressed in units appropriate to the selected device.
For two-component paints, the specific gravity of the mixture must be taken into account, such as the flash point. Specific gravity is measured at 25°C (77°F).
4- Volatile organic matter content
This parameter expresses the amount of volatile organic compounds in the paint per liter of paint. Also in English units, this quantity is expressed in terms of the amount of volatile organic compounds in pounds per gallon.
5- Volatile organic matter content
This parameter is of great importance in paint storage and is the length of time that the paint can be stored in optimal storage conditions. This time is usually one year or less and decreases with increasing temperature of the storage environment. These conditions include storing the paint in standard sealed containers and storing the paint in a closed environment away from sunlight and at a temperature between 4 and 27 degrees Celsius. If the paint is stored in inappropriate conditions, the properties of the paint content may be lost before the expiration date and it cannot be applied. This problem is usually observed in the form of gelling, clumping or the formation of a thick layer of dry paint film.
For more information, read the article “Safety Principles in the Storage and Use of Paint” on this website.
For specialized advice and purchase of marine, coastal, offshore, industrial, and construction paints from Kansai, contact Armanifam.
