Effect of cellulose ether (HPMC/MHEC) on putty properties

Cellulose ether is a common raw material in powdered building materials. It can be widely used in interior and exterior wall putty, waterproof putty, and elastic putty. Cellulose ether plays an important role in improving the construction performance of putty. Putty without cellulose ether has great viscosity, poor scraping, and easy sagging, resulting in material waste. With the increase of cellulose ether addition, the construction performance of putty is significantly improved and enhanced. This is mainly because the molecular structure of cellulose ether contains rich hydroxyl groups. After dissolving in water, it is surrounded by water molecules and absorbs a large amount of water. Under hydration, the volume of the molecule itself expands significantly. At the same time, the molecular chains gradually entangle with each other and form a high-viscosity aqueous solution, which makes it have good thixotropic properties and construction performance, improves the adhesion of putty, and better bonds the substrate. In addition to giving the putty system good construction performance, cellulose ether also gives the putty system excellent water retention and enhances the adhesion of putty. Therefore, the drying time of putty can be adjusted according to its addition amount to avoid cracks and dehydration caused by excessive water loss to meet the requirements of actual use.

Effect of cellulose ether dosage on surface drying time of putty

As can be seen from the figure, as the dosage of cellulose ether increases, the surface drying time of the putty film is prolonged. However, it is not the case that the more cellulose ether is added, the better. If the dosage is too large, the surface drying time will be prolonged accordingly, which will lead to a longer construction period, which is not conducive to the actual engineering requirements. On the other hand, due to its high price, it is more appropriate to determine the dosage of 0.4% ~ 0.6% after comprehensive consideration.