MHEC (Methyl Hydroxyethyl Cellulose) is another cellulose-based polymer that is commonly used as an additive in cement-based rendering applications. It has similar advantages to HPMC, but has some differences in properties. The following are the applications of MHEC in cementitious plasters:
Water retention: MHEC increases the water retention in the plastering mixture, thus prolonging the workability. It helps prevent the mixture from drying prematurely, allowing enough time for application and finishing.
Workability: MHEC improves the workability and spreadability of the plastering material. It improves cohesion and flow properties, making it easier to apply and achieve a smooth finish on surfaces.
Adhesion: MHEC promotes better adhesion of the plaster to the substrate. It helps ensure a strong bond between the plaster and the underlying surface, reducing the risk of delamination or separation.
Sag Resistance: MHEC imparts thixotropy to the plaster mixture, improving its resistance to sag or slump when applied vertically or overhead. It helps to maintain the desired thickness and shape of the plaster during application.
Crack resistance: By adding MHEC, the plastering material acquires higher flexibility and thus enhanced crack resistance. It helps minimize the occurrence of cracks caused by drying shrinkage or thermal expansion/contraction.
Durability: MHEC contributes to the durability of the plastering system. It forms a protective film when dry, increasing resistance to water penetration, weathering and other environmental elements.
Rheology Control: MHEC acts as a rheology modifier, affecting the flow and workability of the rendering mixture. It helps control viscosity, improves pumping or spraying characteristics, and prevents settling or separation of solid particles.
It should be noted that the specific amount and selection of MHEC may vary depending on the specific requirements of the plastering system, such as required thickness, curing conditions and other factors. Manufacturers often provide guidelines and technical data sheets with recommended levels of use and instructions for incorporating MHEC into cementitious gypsum formulations.
Post time: Jun-08-2023