There is a certain relationship between the powder quality of putty powder and HPMC (hydroxypropyl methylcellulose), but the functions and effects of the two are different.
1. Composition and powder characteristics of putty powder
Putty powder is a building material used for wall leveling, repairing and decoration. The main components include base materials (such as cement, gypsum), fillers (such as calcium carbonate) and additives (such as cellulose ether, water retaining agent, etc.). The powder quality of putty powder mainly refers to the fineness, uniformity and feel of its particles during construction. This powder quality is affected by the following factors:
Particle size of filler: Calcium carbonate is usually used as the main filler. The finer the calcium carbonate particles, the finer the powder quality of putty powder, and the better the flatness and smoothness of the wall after application.
Type of base material: For example, cement-based putty powder and gypsum-based putty powder will have different feel and characteristics due to the different base materials used. The particles of cement-based putty powder may be coarse, while those of gypsum-based putty powder may be finer.
Processing technology: In the process of producing putty powder, the degree of grinding and the uniformity of the formula will also affect the powder quality. Better processing technology can produce more delicate and uniform putty powder.
2. The role of HPMC in putty powder
HPMC, namely hydroxypropyl methylcellulose, is a common additive in putty powder. It is a water-soluble polymer that mainly plays the role of thickening, water retention and improving construction performance. HPMC itself does not directly affect the particle fineness (i.e. powder quality) of putty powder, but it has a significant improvement effect on the construction performance of putty powder:
Water retention effect: An important function of HPMC is water retention, which can delay the evaporation of water in putty powder during construction and prevent the putty powder from drying out prematurely during wall construction. This has a positive effect on wall leveling and adhesion, especially in high temperature and dry environment, water retention is particularly important.
Thickening effect: HPMC can increase the viscosity of putty powder, so that it has moderate consistency and easy scraping after stirring. This effect helps control the fluidity of putty powder during construction, reduces the phenomenon of flying and powder falling, and can enhance the bonding force, thereby indirectly improving the feel during construction.
Improve construction performance: The presence of HPMC can make putty powder easier to operate during construction, feel smoother, and present a more uniform and delicate effect when smoothing. Although HPMC does not change the physical fineness of putty powder particles, it improves the overall operating performance and makes the feel of the powder more delicate when applied.
3. Indirect effect of HPMC on the quality of putty powder
Although HPMC does not directly change the particle size or physical fineness of putty powder, it improves the construction effect of putty powder through water retention, thickening, lubricity and other aspects, making putty powder smoother and easier to operate when used. During the construction process, putty powder containing HPMC is easier to apply flat, reducing scratches and unevenness, which makes users subjectively feel that the powder is more delicate.
The water retention of HPMC can prevent shrinkage cracks in putty powder during the wall drying process, which also has a positive effect on improving the overall flatness and smoothness of the wall. Therefore, from the perspective of the final wall effect, HPMC has a certain indirect effect on the fineness of putty powder.
4. Relationship between HPMC dosage and powder quality
The dosage of HPMC also needs to be properly controlled. Usually, the dosage of HPMC in putty powder is relatively small, and excessive use will lead to the following problems:
Over-thickening: If the dosage of HPMC is too much, the putty powder may become too viscous, making it difficult to stir, and may even cause problems such as powder loss and surface stickiness. It is not easy to apply flat during construction, which will affect the final wall effect and give people a feeling of rough powder.
Extend drying time: The water retention effect of HPMC will delay the drying time of putty powder. If the dosage is too much, the wall may not dry for a long time, which is also not conducive to the construction progress.
Therefore, the dosage of HPMC must be within a reasonable range to play its role in improving the quality of putty powder.
The quality of putty powder is mainly determined by the fineness of its base material and filler, as well as the production process and other factors. As an additive in putty powder, HPMC does not directly determine the powder quality, but it has an indirect positive impact on the fineness of its powder quality by improving the water retention, thickening and construction properties of putty powder. Reasonable use of HPMC can make putty powder show better feel and application effect during construction, reduce construction defects, and thus improve the overall flatness and fineness of the wall.
Post time: Sep-30-2024