Renovation of interior and exterior walls: Adhesion of paint coating film

Update time:2022-08-17

Renovation of interior and exterior walls: There are many brands and types of coatings on the market. We have always paid attention to the environmental protection of coatings. In fact, there is another point that is also very important, that is, its physical properties, including: adhesion, contrast ratio, Water and alkali resistance, scrub resistance, stain resistance, artificial weathering resistance, etc., these are the specific indicators to investigate the performance of coatings, so today we mainly talk about its adhesion for interior and exterior wall renovation.

The mutual attraction between two different substances in contact is a manifestation of molecular force. It appears only when the molecules of the two substances are in close proximity. Generally, two solids cannot be in close contact, and the adhesion between them cannot take effect; liquids and solids can be in close contact, and the adhesion between them can work. For example, there is adhesion between paint and the object it is applied to.

The adhesion of the interior and exterior wall renovation paint coating film refers to the firmness of the paint film and the surface of the object to be coated. This binding force is formed by the interaction between the polar groups (such as hydroxyl or carboxyl) of the polymer in the paint film and the polar groups on the surface of the object to be coated. There is pollution or moisture on the surface of the coated object; the paint film itself has a large shrinkage ability; the polymers are cross-linked during the curing process to reduce the number of polar groups, etc. These are all factors that lead to a decrease in paint film adhesion. The adhesion of paint films can only be determined by indirect means. At present, the methods for specifically measuring the adhesion of paint films are divided into three types, namely, the comprehensive measurement method represented by the scratch method and the circle method, the peeling test method represented by the pull-off method, and the method used in combination with solvents and softeners. Test water test method.

Paint with poor adhesion for interior and exterior wall renovation will cause chalking, peeling, blistering, and peeling of the wall surface. The reasons for the decline of adhesion caused by the renovation of interior and exterior walls are: the low molecular substances inside the object to be coated migrate to the surface of the object to be coated and accumulate between the paint film and the surface of the object to be coated, which weakens the polarity of the polymer in the paint film. The force between the polar group and the polar group on the surface of the coated object. Enhancing the adhesion of the coating can prolong the aesthetics of the wall. The main thing is to measure the PH value of the wall before coating, do a good job in the base material treatment of the wall, and apply a good moisture-proof and alkali-resistant primer. After the paint is completely dry, paint the topcoat to enhance the adhesion between the layers and increase the service life of the paint.