Sodium Carboxymethyl cellulose is generally not used in exterior wall coatings but can be used in interior wall coatings for the following reasons:
I. Reasons for not being suitable for exterior wall coatings
1. Insufficient water resistance: Exterior walls are exposed to the natural environment for a long time and have to withstand the scouring of rainwater. Sodium Carboxymethyl cellulose has a certain hydrophilic property and will absorb moisture, which easily leads to problems such as blistering and peeling of exterior wall coatings after encountering water, reducing the protective performance and service life of the coatings.
2. Poor weather resistance: Exterior wall coatings need to withstand various harsh climatic conditions such as ultraviolet rays in sunlight, temperature changes, and wind blowing. Sodium Carboxymethyl cellulose may degrade under long-term outdoor environments, making the performance of the coatings unstable and difficult to maintain a good appearance and protective effect.
3. Insufficient strength: Exterior walls may be subjected to some external impacts and frictions, such as sand and wind, and branches scraping. Sodium Carboxymethyl cellulose cannot provide sufficient strength and hardness for exterior wall coatings, making it difficult to meet the mechanical performance requirements of exterior walls for coatings.
II. Reasons for being suitable for interior wall coatings
1. Good thickening property: In interior wall coatings, Sodium carboxymethyl cellulose can play a thickening role, giving the coatings an appropriate viscosity and facilitating construction and application to ensure that the coatings can evenly cover the wall surface.
2. Water retention: It helps to maintain the moisture in the coatings and prevent the coatings from losing water too quickly during the drying process, so that the coatings have enough time for leveling and curing, improving the construction performance and film quality of the coatings.
3. Improving adhesion: It can enhance the adhesion between the coatings and the interior wall surface, making the coatings not easily fall off and ensuring the decorative effect and service life of the interior wall.
4. Low cost: Compared with some other additives, carboxymethyl cellulose is relatively inexpensive. While meeting the performance requirements of interior wall coatings, it can reduce production costs.
