Introduction to the inspection of emulsion paint polymer film

The inspection of polymer films is actually divided into two aspects: free film inspection and sample inspection. Free film inspection mainly includes: tensile strength, elongation, water resistance, water absorption, air permeability, etc. Only the water resistance test of the polymer film is introduced here. Because the water resistance of the polymer film is of great significance to latex paint, especially real stone paint.

Take a representative sample of the emulsion, apply the emulsion on a glass plate with an applicator (such as 100 µm), and dry it in a Drying Oven at 35°C±2°C for 24h.

You can drop distilled water on the dry film, and then observe how long it takes for the whitening phenomenon to appear. The longer it takes for a drop of distilled water to turn white, the better its relative water resistance.

You can also immerse the coated glass plate in water to observe the change and adhesion of the coating film, such as whitening and cracking. It is judged according to the length of time from immersion in water to the appearance of whitening and cracking, and the size of the change.

Through a certain amount of experiments, the time interval of whitening can be obtained, which can be used as an index for future control .

The inspection items of the sample include water resistance, acid resistance, alkali resistance, chemical resistance, solvent resistance,

Resistance items such as weather resistance, physical property items such as gloss, fluidity, and hardness. These are often tested on the basis of compositional formulations, therefore, such tests are covered in the section on latex paint product testing.