Polyurethane Paint
Polyurethane paint is also called PU paint, and is usually divided into one-pack and two-pack systems. The one-pack system can be further divided into three types: oil-modified, block, and moisture-cured. Most products found on the market belong to Polyol-cured (two-pack) and moisture-cured (one-pack) (1), which are suitable for DIY.
Before the two-pack PU paint is used, the base and the curing agent must be well mixed. The curing agent, polyisocyanate, is toxic, and care must be taken when using it. The moisture-cured type must be used and dried in an environment of high relative humidity.
PU paint has good water, chemical, and weather resistance, and is frequently used in painting outdoor construction.
In choosing PU paint, consumers must know that the L type PU paint ages easily and is not suitable for light painting. To prevent aging, it is better to use N or NN type PU paint.
When using PU paint, one must follow the mixing ratio instructed by the manufacturer and use the specified dilution to ensure its characteristics, the curing effect, and the best function of its film. Usually, an air spray is used for PU paint (2), and thickness of each coat should not be too thick, otherwise the painted surface will be blistering.
- The moisture-cured PU paint should belong to the two-pack system: One pack is the paint itself; the other pack is the air's moisture.
- The paint should be ordered specially to prevent a blistering surface if the application is by brush and roller.