Hydroxypropyl Methyl Cellulose (HPMC) is a multifunctional chemical material widely used in building materials, especially in the production and application of putty powder. Putty powder is a material used for building surface treatment. Its main function is to fill the unevenness of the wall surface and provide a smooth and uniform base layer, which provides a good foundation for subsequent coating or decoration processes.
Basic properties of HPMC
HPMC is a non-ionic cellulose ether obtained by chemically modifying cellulose. It has good water solubility and can be quickly dissolved in cold water to form a transparent or translucent colloidal solution. HPMC contains hydroxyl and methyl groups in its molecular structure, so it has good thickening, suspension, dispersion, emulsification, bonding, film formation, and protective colloid functions. In addition, it also has excellent water retention and stability, and is not easily affected by temperature and pH changes.
The role of HPMC in putty
Thickener and suspending agent: HPMC can increase the viscosity of putty slurry, making it easier to apply and shape during construction, while preventing the sedimentation of pigments and fillers during storage and construction.
Water-retaining agent: HPMC has excellent water-retaining properties, which can reduce water loss during construction, extend the open time of putty, and ensure the uniformity and stability of putty during drying. This can effectively prevent shrinkage cracks in the putty layer and improve construction quality.
Lubricating effect: HPMC can improve the lubricity of putty, making it smoother during construction, reducing construction difficulty, reducing the labor of operators, and improving work efficiency.
Binder: HPMC can enhance the bonding force between putty and substrate, making the putty layer more firmly attached to the wall surface and preventing it from falling off.
Improving construction performance: HPMC can improve the operability of putty, making it easier to spread and smooth when applying and scraping, reducing construction marks, and ensuring the smoothness and beauty of the wall.
How to use HPMC
During the production process of putty, HPMC is usually added to the dry mix in the form of powder. The amount of addition varies depending on the type of putty and performance requirements. Generally speaking, the amount of HPMC is controlled at about 0.2%~0.5% of the total amount of putty. In order to ensure that HPMC can fully play its role, it is usually necessary to add it slowly during the mixing process and keep it mixed evenly.
Advantages and disadvantages of HPMC in putty
Advantages:
Good environmental protection: HPMC is non-toxic and harmless, does not contain heavy metals and harmful substances, meets environmental protection requirements, and is friendly to construction personnel and the environment.
Stable performance: HPMC has strong adaptability to changes in environmental conditions such as temperature and pH, stable performance, and is not easy to deteriorate.
Wide applicability: HPMC is suitable for various substrates and coating systems, and can meet different construction requirements.
Disadvantages:
High cost: Compared with other traditional materials, HPMC has a higher cost, which may increase the production cost of putty products.
Sensitive to water quality: HPMC has high requirements for water quality, and differences in water quality may affect its solubility and performance.
The application of HPMC in putty has significant advantages. It not only improves the construction performance of putty, but also improves the physical and chemical properties of putty. Although its cost is relatively high, the quality improvement and construction convenience it brings make it widely used in high-quality construction projects. With the continuous advancement of building materials technology, the application prospects of HPMC in putty and other building materials will be broader.
Post time: Aug-09-2024