Application of Cellulose in Putty Mortar
Release Time:
2022-04-26
Source:
In the aesthetic sensibilities of Eastern cultures, the smooth, even surface of a building is generally regarded as beautiful. It is precisely for this reason that putty has come into widespread use. Putty is a thin-layer plastering material that plays a crucial role in both the decorative and functional aspects of a building. The three layers of decorative coating—base wall, putty leveling layer, and finish coat—serve distinct purposes and exhibit different elastic moduli and deformation coefficients. When ambient temperature and humidity fluctuate, these three layers deform to varying degrees. Therefore, the putty and finish-coat materials must possess an appropriate elastic modulus, leveraging their inherent elasticity and flexibility to relieve concentrated stresses, thereby resisting cracking of the base layer and preventing delamination and flaking of the finish coat. A high-performance putty should demonstrate excellent substrate-wetting properties, re-coatability, smooth and easy application, and sufficient working time, while also exhibiting superior adhesion, flexibility, sandability, and durability.
As the most important component of the commercialization of building materials in China, the country’s ready-mixed mortar industry has, under the combined influence of market forces and policy interventions, gradually transitioned from the market introduction phase to a period of rapid growth. The use of ready-mixed mortar is an effective means of enhancing construction quality and promoting civilized site practices; its widespread adoption and application facilitate the comprehensive utilization of resources and represent a key measure for sustainable development and the advancement of a circular economy; moreover, the use of ready-mixed mortar can substantially reduce the rate of rework in construction projects, increase the degree of mechanization, improve construction efficiency, and alleviate labor intensity, thereby continuously enhancing residential comfort while reducing overall building energy consumption.
In the commercialization of ready-mixed mortar, cellulose ethers have played a milestone role. Their judicious application has made mechanized construction of ready-mixed mortar feasible; high-performance hydroxypropyl cellulose (HPMC) can markedly enhance the workability, pumpability, and sprayability of mortar; its thickening capability improves the wetting of the base wall by the fresh mortar, thereby increasing bond strength; it allows adjustment of the mortar’s open time; its unparalleled water-retention capacity significantly reduces the likelihood of plastic cracking; and it promotes more complete cement hydration, thus enhancing overall structural strength. Taking ordinary plastering mortar as an example, a high-quality mortar mix should exhibit excellent workability: easy mixing, good wettability of the base wall, smooth and non-sticky application, sufficient working time with minimal consistency loss, and ease of leveling. The hardened mortar, in turn, should demonstrate superior mechanical properties and surface appearance: appropriate compressive strength, strong bond to the base wall, good durability, a smooth and even surface free from hollows, cracks, or powdering.
