Hydroxyethyl Cellulose * Exterior Paint

Exterior wall paint is a protective layer on the surface of a building, which has functions such as waterproofing, anti-corrosion, and weather resistance. In the production process of exterior wall paint, adding a certain proportion of hydroxyethyl cellulose can play the following roles:

Ⅰ. Thickening effect

1. Suspended solid particles: Exterior wall paints usually contain solid ingredients such as pigments and fillers, such as titanium dioxide, calcium carbonate, etc. Hydroxyethyl cellulose (HEC) can increase the viscosity of the paint, so that these solid particles are evenly suspended in the paint system. Taking the textured exterior wall paint containing mica flakes as an example, HEC can prevent the mica flakes from settling due to gravity, ensuring that the texture and color of the paint applied everywhere are uniform during storage and use.

2. Improve construction performance: The thickened exterior wall paint is easier to control during construction. For brush application, the appropriate viscosity can make the paint adhere better to the brush, and it will not be too thin and flow when applied to the wall, which is convenient for construction personnel to control the coating thickness. In spray application, it can prevent excessive atomization of the paint, so that the paint can be evenly attached to the wall, and reduce the splashing and sagging caused by too thin paint.

Ⅱ. Adjust rheology

1. Optimize construction operability: HEC can adjust the rheology of the exterior wall paint to make it have shear thinning characteristics. During the construction process, when the paint is subjected to shear force (such as the force generated by stirring, brushing, spraying, etc.), the viscosity will temporarily decrease, making it easier to operate. For example, when a roller is used for construction, the shear force exerted by the roller on the paint will reduce the viscosity of the paint, making it easier to transfer from the roller to the wall; when the shear force disappears, the viscosity is restored, and the paint can maintain good coverage and texture on the wall.

2. Balance leveling and anti-sagging: By adjusting the rheology, HEC helps to balance the leveling and anti-sagging of exterior wall paint. Leveling refers to the ability of the paint to automatically level the surface after application, and anti-sagging is the performance of preventing the paint from flowing on vertical or inclined surfaces. For exterior wall paint, good leveling can make the wall coating surface smooth and beautiful, while good anti-sagging can ensure that the paint will not flow due to gravity when it is constructed at a high altitude or the wall is uneven.

III. Water retention effect

1. Improve film quality: During the film formation process of the paint, HEC can form a water-retaining layer on the surface of the paint to slow down the evaporation rate of water. The film-forming substances (such as emulsions) in exterior wall paints need to be in a certain moisture environment to fully blend and form a continuous paint film. If the water evaporates too quickly, the film-forming substances may not react completely, resulting in cracking, powdering and other problems in the paint film. The water retention effect of HEC provides sufficient time and a suitable moisture environment for the film-forming substances, thereby improving the quality of the paint film and enhancing the durability of the exterior wall coating.

2. Adapt to environmental changes: Exterior wall paints are affected by different environmental conditions, such as high temperature, low humidity or high humidity. The water retention effect of HEC can help the paint better adapt to these environmental changes. In a dry environment, it can prevent the paint from failing to form a film normally due to excessive water loss; in a humid environment, it can adjust the water evaporation rate to avoid affecting the film formation speed and quality due to excessive water.

IV. Enhanced stability

1. Extended shelf life: During storage, HEC helps maintain the stability of the exterior wall paint system. It can prevent the agglomeration and sedimentation of components such as pigments and fillers, so that the paint can remain uniform after being stored for a period of time.

2. Improve chemical stability: HEC can also improve the chemical stability of exterior wall coatings, making them more resistant to corrosion by chemicals such as acids and alkalis. Exterior walls are often exposed to acid rain, alkaline exudates from building materials, etc. Coatings containing HEC can better cope with the effects of these chemicals, reduce damage to the coating, and maintain the decorative effect of the exterior walls.