Revealing the role of elastic waterproof interface agent in plastering plaster
1 Types of interface agents
Interface agents are a general term for a class of materials that are 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, plaster gypsum interface agent, etc. It can be divided into 2 major categories according to its composition:
1. Dry powder interface agent. Dry powder interface agent is a powder composed of inorganic gelling materials such as cement, fillers, polymer powder and related additives. It has high adhesion, excellent water resistance and aging resistance. When using, mix it with water in a certain proportion and mix it before use.
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 two-component products according to their composition and applicable base layer. When using two-component products, cement needs to be added in proportion. The one-component emulsion interface agent only needs to be mixed with water in proportion to be used.
2 Composition of interface agent for plastering gypsum
It is an emulsion-type interface product that uses special elastic acrylic emulsion as the main component and is compounded with a variety of additives. It has excellent permeability and can fully infiltrate the surface of the base material, making the base layer dense and improving the adhesion of the smooth interface. Suitable for surface treatment of concrete, autoclaved aerated blocks, autoclaved fly ash bricks, aluminum molds, prefabricated wall panels, capillary network and other substrates. Generally called elastic waterproof interface agent.
3 Functions of elastic waterproof interface agent
■ Improve the bonding strength. After the demoulding of concrete construction, the smooth and dense concrete surface can easily cause difficulties in subsequent construction and defects in later projects, such as cracking, hollowing, and falling off of plastering mortar, especially on aluminum formwork walls. more serious. Spraying an elastic waterproof interface agent on a smooth and dense concrete surface can improve the bonding strength between the plaster and the wall base. Experiments have proven that for walls painted with interface agents, during pull-out testing, the failure interface is located within the block wall. The tensile bonding strength between the plaster layer and the base layer can be increased by more than 1 times.
■ Reinforcement base materials, such as aerated concrete blocks and lightweight boards, have low surface strength. Spraying an elastic waterproof interface agent on the surface can enhance the mechanical strength of the surface of the wall material and improve the bonding strength between the plastering gypsum and the wall base.
■ It has a certain waterproof and moisture-proof function. Gypsum is very hygroscopic. Especially the backhand wall of the bathroom and the wall around the window have a large amount of moisture. The interface agent treatment can effectively reduce the impact of moisture on indoor putty, paint and wallpaper. damage and reduce the risk of putty powdering, mildew, and shelling.
The putty on the backhand wall of the bathroom is moldy▲
■ Reduce the water absorption rate of the base material. Aerated concrete blocks and lightweight boards have high water absorption rates, which can easily cause the plastering gypsum to lose water and fail to fully hydrate. It has low strength and is easy to depowder. Interface agent treatment can effectively reduce the base material’s water absorption rate. The water absorption rate ensures a stable gypsum hydration environment and greatly improves the smoothness of the gypsum mortar. Close the pores on the concrete surface to avoid or greatly reduce the problem of bubbles produced by plastering plaster during construction.
Without interface agent on the base layer, the dusting is serious▲
Without interface agent on the base layer, there are serious bubbles▲
■ High elasticity, effectively buffering the stress deformation of the base layer. Due to environmental changes in temperature and humidity, the base wall itself always undergoes shrinkage and deformation, and is affected by the shear force of uneven settlement. Interface agent treatment can buffer or eliminate the wall between interfaces. The accumulation of material shrinkage stress effectively reduces hollowing and cracking of the plaster layer. We tested the stress buffering effect of boards with and without interface agent under 3 cm deformation. It can be clearly seen that the gypsum and base layer of the board with interface agent are not peeled off (hollowed out).
The hollow drum cracked without interface agent treatment▲
The unhollowed and cracked drums treated with interface agent▲
■ Environmentally friendly and formaldehyde-free. Compared with the common 108 glue and color paste interface products on the market, or interface products with lower solid content, the elastic waterproof interface isThe agent is a high-performance interface treatment material that is non-toxic, odorless, and environmentally friendly.
4 Standardized construction process
● Ratio: lotion: water (1:3) ratio
●Consumption: 0.05kg/m2 (emulsion)
● Construction thickness: 40um
● Standardized construction technology: Mix the interface agent according to the proportion, and use a stirrer to mix it thoroughly. Use spraying or roller coating. When spraying, the distance between the spray gun head and the wall is about 30cm, and the spray gun should be sprayed at a 45-degree angle. The spray gun should be from the top to the bottom, spray 2 times evenly in an S-shaped path from left to right to ensure that the interface agent is evenly sprayed. After the interface agent is sprayed, it will look light blue, sticky to the touch, and no powder will fall off when the surface of the block is scratched. The next step can be carried out 2 hours after the spraying is completed.
