Coating is a coating material widely used in construction, automobile, shipbuilding and other industries, and the units involved mainly include:
Area Units: Coatings are usually calculated in terms of coating usage per square meter (m²) to allow for calculation of the total amount and cost of coating required.
Thickness unit: The thickness of the coating is usually expressed in microns (μm) or millimeters (mm) in order to control the thickness and uniformity of the coating.
Units of Weight: The weight of paint is usually expressed in kilograms (kg) or grams (g) to allow calculation of the total amount of paint required and cost.
Concentration unit: The concentration of paint is usually expressed in weight percent (wt%) or volume percent (vol%) in order to control the proportion and quality of paint components.
Drying time unit: The drying time of the paint is usually expressed in minutes (min) or hours (h) in order to calculate the construction time and production efficiency of the paint.
Viscosity unit: The viscosity of the coating is usually expressed in Newton (N) or Pascal second (Pa·s) in order to evaluate the fluidity and coating performance of the coating.
Coating roughness is usually expressed in microns (μm) in order to control the quality and appearance of the coated surface.
The application thickness of coatings is usually expressed in terms of wet film thickness (WFT) and dry film thickness (DFT). Wet film thickness refers to the thickness of the coating before drying after application, usually expressed in millimeters (mm) or microns (μm); dry film thickness refers to the thickness of the paint after drying, usually in microns (μm) or millimeters (mm) expressed as a unit.
Weather resistance of coatings : usually expressed in hours (h) or years (y) in order to evaluate the durability and service life of coatings under various environmental conditions.
The color of paint : It is usually expressed by the ternary color value of colorimetry, that is, RGB (red, green, blue) or CMYK (cyan, magenta, yellow, black) and other color systems. In addition, the color of paint can also be described and compared using standards such as Color Charts.
Solid content of paint : usually expressed in weight percent (wt%), which represents the percentage of actual solid particles in the paint. In general, the higher the solids content of the coating, the better the hardness, abrasion resistance and durability of the coating film.
Surface dry time and hard dry time of paint : usually expressed in hours (h) or minutes (min). Tack-free time refers to the time until the surface of the paint can be touched without leaving fingerprints, usually half of the film thickness. Hard drying time refers to the time after the paint is applied to reach the final hardness, usually the time after the coating film dries.
Viscosity of a paint : Usually expressed in kilobores (KU), this is a method of calculating the viscosity of a paint by measuring the time it takes for the paint to pass through a specific pore size in the gel state.
Tensile strength, compressive strength, bending strength of coatings : mechanical properties such as these are usually expressed in units of Newton (N) or megapascal (MPa), and these performance indicators are usually related to the performance of the material or structure being coated.
Coating volatility and solvent content : Usually expressed in weight percent (wt%), these performance indicators can affect the service life and environmental impact of the coating.
Resistivity of coatings : : Usually expressed in ohm-meter (Ω·m) or kilo-ohm-meter (kΩ·m), this performance parameter is usually used to evaluate the electrical insulation performance and conductivity of the coating.
Rheological properties of coatings : usually described by parameters such as shear stress, shear rate and viscoelasticity. These parameters are usually expressed in Newtons (N) or Pascals (Pa) and are used to evaluate the rheological properties of coatings, such as flow, stability, shear performance, etc.
Optical properties of coatings : usually described by parameters such as transparency, reflectivity, absorptivity, and refractive index. These parameters are usually expressed as percentages or numerical values, and are used to evaluate the optical properties of coatings, such as reflection and refraction of light wavelengths, etc.
Corrosion resistance of coatings : usually evaluated by parameters such as salt spray test and damp heat test. These tests are usually expressed in units of time (hours or days) and are used to evaluate the resistance of a coating to a corrosive environment.
The flammability and fire safety of coatings are usually described by parameters such as ignition point, auto-ignition temperature, and smoke density. These parameters are usually expressed in the form of temperature, mass percentage, etc., and are used to evaluate the safety performance of coatings under fire conditions.
Coating adhesion : : usually expressed in the form of N/m or MPa, used to evaluate the bonding strength between the coating and the surface of the object to be coated.
The fluidity of the paint is usually expressed in seconds, which usually refers to the flow time of the paint at standard temperature and standard humidity.
The pH value of the paint : usually expressed as a value from 0-14, used to evaluate the acid-base properties of the paint.
Water Absorption of Coating : Usually expressed as a percentage, it is used to evaluate the coating's ability to absorb water.
Abrasion resistance of coatings : usually expressed in the form of weight loss or number of wear cycles, etc., used to evaluate the anti-wear performance of coatings.
Chemical resistance of coatings : Usually, the resistance to chemicals such as solvents, acids, and alkalis is used as a standard to evaluate the chemical corrosion resistance of coatings.
Particle Size Distribution of Coatings : Usually expressed as a numerical distribution or a volume distribution, it is used to assess the size and uniformity of particles in a coating.
Storage stability of coatings : usually described by shelf life or storage conditions, used to evaluate the storage stability and service life of coatings under different conditions.
Hardness of the coating : usually expressed in Dublin hardness (DHD) or Perkins hardness (Pencil Hardness), which is used to evaluate the scratch resistance of the coating.
Surface Tension of a Coating : Usually expressed in Newtons per meter (N/m) or pounds force per inch (lb/in), it is used to assess the wettability and adhesion of a coated surface.
In short, there are many units and performance parameters involved in coatings. Different parameters can describe the performance and quality of coatings from different angles, and provide important reference information for manufacturers and users. In practical applications, it is necessary to select the corresponding units and performance parameters according to the specific coating type and application field to evaluate the performance and quality of the coating.
Cheryl Roberts
Dr. Stephen Bailey