Phenomenon：The gloss of the paint film is very low after drying, or the gloss drops and the hazy phenomenon appears after painting soon.

Phenomenon：The dry, non-sticky paint film surface then appears sticky again.

Phenomenon：The bubbles are suspended in the paint film without breaking, which seriously affects the appearance. Generally it appears in the bright light system. This phenomenon is caused by the reaction of isocyanate (-NCO) and moisture (H2O). Therefore, dark bubble is unique to polyurethane paint.

Phenomenon：The color of the paint film changes, generally yellowing or fading.

Phenomenon：The phenomenon of cracks on the surface of the paint film under the influence of internal stress, external impact or environmental conditions.

Phenomenon：After drying, the gloss of the paint film is not good, and it appears wizened and not full phenomenon.

Phenomenon：A paint film defect in which the painted surface is not painted or does not cover the base color.

Phenomenon：When spraying the same or different kinds of paint on the dry paint film, the lower paint film will be eroded, swollen, and softened during the coating or drying period. This causes the primer film to separate from the surface of the substrate, causing wrinkles, swelling, blistering, and loss of gloss.

Phenomenon：After the paint film dries, there will be protruding bubbles of different sizes or bubble marks after overflow.

Phenomenon：The phenomenon of irregularly protruding particles or filamentous fibrous objects on the surface of the paint film or on the entire surface.