Demystifying the role of elastic waterproof interface agent in plastering gypsum

Uncover the role of elastic waterproof interface agent in plastering gypsum
1 Types of interface agents

Interface agent is a general term for a class of materials used to improve or completely change the physical and technical properties and surface chemical properties of the material surface by treating the surface of the object. According to the scope of application, it includes concrete interface agent, extruded board interface agent, rock wool board interface agent, ceramic tile interface agent, plastering gypsum interface agent, etc. According to the composition, it can be divided into two categories:

1. Dry powder interface agent, dry powder interface agent is a powder composed of inorganic cementitious materials such as cement, fillers, polymer rubber powder and related admixtures. It has high adhesion, excellent water resistance and aging resistance. When using, mix it with water in a certain proportion and use it.
2. Emulsion-type interface agent, emulsion-type interface agent is made of chemical polymer materials as the main component, supplemented by other fillers. The emulsion type is divided into single-component and double-component according to its composition and applicable base layer. When using two-component products, cement should be added in proportion. The one-component emulsion type interface agent can be used only by adding water in proportion.
2 Composition of interface agent for plastering plaster
It is an emulsion-type interface product composed of special elastic acrylic emulsion as the main component and compounded with various additives. With excellent permeability, it can fully infiltrate the surface of the substrate, make the base layer dense, and improve the adhesion of the smooth interface. It is suitable for surface treatment of substrates such as concrete, autoclaved aerated blocks, autoclaved fly ash bricks, aluminum molds, fabricated wall panels, and capillary networks. Generally known as elastic waterproof interface agent.
3 The function of elastic waterproof interface agent
■ Improve the bonding strength. After the demoulding of the concrete construction, the smooth and dense concrete surface is likely to cause subsequent construction difficulties and later engineering defects, such as plastering mortar cracking, hollowing, and falling off, especially on aluminum formwork walls. more serious. Spraying the elastic waterproof interface agent on the smooth and dense concrete surface can improve the bonding strength between the plastering gypsum and the base of the wall. Experiments have proved that the wall that has been brushed with the interface agent, when pulled out and tested, the failure interface is located in the block wall. The tensile bonding strength between the plastering layer and the base layer can be increased by more than 1 times.
■ Reinforce the base material, aerated concrete blocks and light boards have low surface strength. Spraying elastic waterproof interface agent on the surface can enhance the mechanical strength of the wall material surface and improve the bonding strength between the plastering gypsum and the wall base.

With a certain waterproof and moisture-proof function, gypsum has strong hygroscopicity, especially on the backhand wall of the bathroom and the wall around the window. The moisture is relatively high, and the interface agent treatment can effectively reduce the impact of moisture on indoor putty, paint, and wallpaper. damage and reduce the risk of putty pulverization, mildew and shelling.

Moldy putty on the backhand wall of the bathroom▲
■ Reduce the water absorption rate of the base material. The high water absorption rate of the air-entrained concrete block and the light board can easily cause the plastering gypsum to lose water and cannot be completely hydrated. Excellent water absorption, ensuring the stability of the gypsum hydration environment, and greatly improving the smoothness of gypsum mortar scraping. Close the pores on the concrete surface, avoid or greatly reduce the problem of air bubbles in plastering plaster during construction.
Serious powder removal without interface agent at the grassroots level▲
Serious air bubbles without interfacial agent on the base layer▲
■ High elasticity, effectively buffering the stress and deformation of the base layer. Due to the environmental changes of temperature and humidity, the wall of the base layer is always shrinking and deforming. The shear force of uneven settlement can buffer or eliminate the wall between the interfaces through the interface agent treatment. The accumulation of material shrinkage stress can effectively reduce the hollowing and cracking of the plaster layer. For the plates with and without interface agent, we tested the effect of buffering stress under the deformation of 3 cm. It can be clearly seen that the gypsum and the base layer have not been peeled off (empty drum) for the plate with interface agent.
Hollow cracking without interface agent treatment▲
Non-hollowing cracking after interface agent treatment▲

Environmentally friendly and formaldehyde-free. Compared with the common 108 glue and color paste interface products on the market, or the interface products with lower solid content, the elastic waterproof interface agent is a high-performance interface treatment material, non-toxic, Odorless, green and environmentally friendly.

4 Standardized construction process
● Ratio: emulsion: water (1:3) ratio
● Consumption: 0.05kg/m2 (emulsion)
● Construction thickness: 40um
● Standardized construction process: mix the interface agent according to the proportion and mix it fully with the agitator. When spraying, the distance between the nozzle of the spray gun and the wall is about 30cm, and spray at an angle of 45 degrees. The spray gun should be from the top From left to right, spray 2 times evenly in an S-shaped route to ensure that the interface agent is evenly sprayed. After the interface agent is sprayed, the appearance is light blue, it is sticky to the touch and there is no powder falling off the surface of the block when it is scratched. The next step can be carried out 2 hours after the spraying is completed.