What you need to know about choosing conductive carbon black for polyurethane paint

The polyurethane paint film is bright and plump, hard and wear-resistant, resistant to oil, acid, chemicals and industrial waste gas, good electrical properties, and can be miscible with a variety of resins. People who are engaged in the production or processing of pigment carbon black have such experience. Although the color of carbon black is black, due to the different types of carbon black, when you observe carefully, you will find that there will be some subtle changes in color. From the perspective of blackness, the smaller the particle size of carbon black, the higher the blackness; from the perspective of hue, the large particle size varieties have a blue phase, and the small particle size varieties have a red phase.

Muddy: The varnish is opaque, and the resulting turbid phenomenon is called turbidity. The main reason is improper choice of solvent, moisture absorption, water content, etc. Choose a suitable solvent, and add some butanol, turpentine, and benzene to solve the problem.

Thickening: The reason is: the acid value of the paint is high, and the saponification reaction occurs with the alkaline pigment; the barrel leaks and the solvent volatilizes; the water is mixed in the barrel; the storage temperature is too high, which accelerates the polymerization of the paint. Remedy: add the corresponding solvent, add water if there is water, appropriate amount of butanol, stir evenly and adjust the viscosity before use.

Precipitation and agglomeration: Reason: the storage time is too long; the pigment proportion is too large; the paint viscosity is too low; the fineness is too large. Remedy: pour out the upper paint liquid, stir the sediment first, then add the paint liquid and stir evenly before use.

Skinning: First of all, it is explained that the oxidatively dried paint contains a drier. After the paint is brushed, the solvent volatilizes and oxidatively dries. Generally, the time is controlled according to the standard. Too fast drying will easily affect the weather resistance of the paint film. Causes of crusting: Generally, the lid of the barrel is not tightly leaked or the barrel is not full; or the dosage of surface drying is large; the anti-skinning agent is leaked; the container is placed open during the construction process. Some barrels are crusted and should be used after removing the patent skin and filtering. If the construction is to be placed, a layer of thinner should be sprinkled on it. In the case of nitro lacquer crusts, banana water can be used to melt the crusts without affecting the quality.

Pseudo-thickness: also known as thixotropy, it is like liver transformation when it is still, and it flows when it is stirred, and more lithopone occurs. In the color paint of carbon black for polyurethane paint, it is generally not called paint film sickness.