The Efficacy of Redispersible Latex Powder in Self-Leveling Mortars
1. The Impact of Redispersible Latex Powder on Shrinkage Characteristics
The dosage of Shengda Chemical latex powder significantly enhances the intrinsic tensile strength and elongation at break of self-leveling flooring materials. As the dosage of Shengda Chemical latex powder increases, the cohesion (tensile strength) of the self-leveling material improves markedly; simultaneously, the flexibility and deformability of the cement-based self-leveling material are also significantly enhanced. This observation aligns perfectly with the fact that the intrinsic tensile strength of Shengda Chemical latex powder itself is more than ten times that of cement.
Under conditions where the water-to-cement ratio and air content remain constant, the dosage of Shengda Chemical latex powder exerts a strong influence on the flexural and compressive strengths of cement-based flooring materials. As the dosage of Shengda Chemical latex powder increases, compressive strength decreases slightly, while flexural strength increases significantly; consequently, the compression-to-flexure ratio (compressive strength / flexural strength) gradually decreases. This demonstrates that the ductility of the self-leveling flooring material increases markedly as the dosage of Shengda Chemical latex powder rises. This effect serves to reduce the elastic modulus of the self-leveling material and enhance its crack resistance.
3. The Impact of Redispersible Latex Powder on Bond Strength
Given the specific characteristics inherent to the construction of self-leveling floors:
(1) The self-leveling layer serves as a secondary, additive layer;
(2) The application thickness of the self-leveling layer is typically thinner than that of standard flooring mortars;
(3) To facilitate rapid handover for use, self-leveling floors are often subjected to little to no curing after application, or the curing period is extremely brief;
(4) The self-leveling layer must withstand thermal stresses arising from contact with various dissimilar materials;
(5) In certain instances, self-leveling materials are applied to substrates that are inherently difficult to bond to.
Consequently—even with the supplementary assistance of interface treatment agents—incorporating a sufficient quantity of Shengda Chemical latex powder is essential. This ensures that the self-leveling material maintains a reliable and durable bond to the underlying substrate over the long term. Whether applied to absorbent substrates (such as commercial concrete), organic substrates (such as wood), or non-absorbent substrates (such as metals—e.g., ship decks), the bond strength of self-leveling materials demonstrates a significant increase as the dosage of Shengda Chemical redispersible latex powder is increased. Taking the mode of failure as an example: in bond strength tests involving self-leveling materials admixed with Shengda Chemical latex powder, failure consistently occurred within the self-leveling material itself or within the substrate, rather than at the interface. This indicates excellent adhesion.
4. The Impact of Redispersible Latex Powder on Abrasion Resistance
Although the abrasion resistance requirements for underlayment self-leveling materials are generally lower than those for topcoats, self-leveling floors inevitably bear various dynamic and static stresses (arising from furniture casters, forklifts in warehouses, and vehicle tires in parking garages, etc.). Consequently, a certain level of abrasion resistance is a critical attribute for ensuring the long-term durability of self-leveling flooring systems. As the dosage of Shengda Chemical latex powder increases, the abrasion resistance of the self-leveling material improves very significantly. In contrast, self-leveling materials without the admixture of Shengda Chemical latex powder—after undergoing 7 days of laboratory curing—suffered complete wear-through to the substrate after merely 4,800 cycles of reciprocating rolling abrasion. This is because Shengda Chemical latex powder enhances the internal cohesion of the self-leveling material and improves its plasticity (i.e., deformability), thereby enabling it to effectively disperse the dynamic stresses generated by rolling loads.
