Hydroxypropyl Methylcellulose (HPMC), as an important building material additive, is widely used in porcelain coatings, especially in the formula of dry powder porcelain coatings. It can not only improve the construction performance of the coating, but also improve the water resistance, adhesion and operability of the coating.
1. Properties of Hydroxypropyl Methylcellulose
Hydroxypropyl Methylcellulose is a water-soluble polymer compound modified from natural plant cellulose. Its main characteristics include:
Thickening: KimaCell®HPMC can significantly increase the viscosity of the coating, making the coating more stable during construction.
Water solubility: It has good water solubility and can form a stable solution in water.
Film-forming property: It can form a uniform film and improve the surface smoothness and uniformity of the coating.
Adhesion: Improve the adhesion of the coating to the base surface (such as cement, masonry, wood, etc.).
Improve the workability of the coating: It can adjust the fluidity and water retention of the dry powder coating, extend the construction time, and avoid premature drying.
2. The role of hydroxypropyl methylcellulose in dry powder porcelain-like paint
In dry powder porcelain-like paint, HPMC mainly plays the following roles:
Thickening and adjusting viscosity: The thickening effect of HPMC makes the paint have good rheology during preparation and use, and it is not easy to produce sagging.
Improving construction performance: By adjusting the smoothness and water holding capacity of the paint, HPMC can improve the operability during construction, especially in high temperature or dry environment, it can effectively extend the open time of the paint, making the paint easier to apply and trim.
Improving adhesion: HPMC can enhance the adhesion between the paint and the substrate, especially on cement substrates or masonry substrates, providing stronger adhesion and reducing the phenomenon of paint shedding.
Preventing sedimentation and stratification: HPMC has good suspension properties, which can effectively avoid the sedimentation of dry powder paint during storage and ensure the uniformity of the paint.
Enhancing water resistance and crack resistance: HPMC can improve the water resistance of the coating, increase the crack resistance of the coating, and make the coating more stable when it is wet or the external environment changes greatly.
3. Typical formula of dry powder imitation porcelain paint
Dry powder imitation porcelain paint usually contains the following main components:
Inorganic fillers: such as talcum powder, heavy calcium powder, etc. These fillers are used to adjust the texture and hardness of the paint and help the coating to obtain a good surface effect.
Resin or emulsion: Commonly used resins include acrylic resin, polyurethane resin, etc., which can enhance the adhesion, hardness and weather resistance of the paint.
Modified cellulose: such as HPMC, the main function of this type of substance is to adjust the viscosity, fluidity, operability and stability of the paint.
Colorant: such as pigment, used to adjust the color of the paint, common ones are titanium dioxide, carbon black, etc.
Preservative: used to prevent the growth of microorganisms in the paint and ensure the service life of the paint.
Plasticizer and leveling agent: used to improve the surface smoothness of the coating and avoid irregular texture on the coating surface.
4. The amount and ratio of HPMC in dry powder imitation porcelain paint
In dry powder imitation porcelain paint, the amount of HPMC added usually accounts for about 0.5%-2% of the entire paint formula. The specific ratio depends on the required coating performance. The following is a typical formula ratio (taking 10 kg dry powder coating as an example):
Inorganic filler (talcum powder, heavy calcium powder, etc.): about 6-7 kg
Resin: about 1.5-2 kg
Hydroxypropyl methylcellulose (HPMC): about 0.05-0.2 kg
Pigment (such as titanium dioxide): about 0.5-1 kg
Preservative: about 0.05 kg
Plasticizer and leveling agent: about 0.1 kg
The specific adjustment of the formula should be determined according to different construction requirements and performance requirements, especially under the climatic conditions of different regions, the amount of HPMC used needs to be optimized accordingly.
5. Usage and precautions
When using HPMC, it is recommended to follow the following steps:
Pre-wetting before mixing: KimaCell®HPMC powder should be mixed with water before adding other raw materials, so that it can fully absorb water and swell before adding other ingredients, so as to avoid HPMC agglomeration.
Slow addition: When mixing other dry powder ingredients, HPMC should be added slowly to avoid incomplete dissolution due to too fast addition.
Evenly mixed: In the formula, all ingredients need to be evenly mixed to ensure that HPMC can fully play its role in the coating.
Storage conditions: Dry powder imitation porcelain coatings should be stored in a dry and cool place to avoid high temperature and humidity affecting the quality of the coating.
The application of hydroxypropyl methylcellulose in dry powder imitation porcelain coatings can significantly improve the construction performance, adhesion and water resistance of the coating, making the coating more stable and durable. Through reasonable formula design and use methods, the advantages of HPMC can be fully utilized, the comprehensive performance of the coating can be improved, and different construction requirements can be met. In actual applications, the amount of HPMC added needs to be adjusted according to the specific situation to ensure that the coating achieves the desired effect.
Post time: Feb-12-2025