Application analysis of additives in water-based waterproof coatings.

as a waterproof coating raw material, its use is generally very small, only about 10% of the weight of the formula, but it plays a very large role. Add additives to waterproof coatings, reduce the appearance of paint defects and coating defects, but also waterproof coating production and construction control, especially the addition of certain additives, can increase the function of waterproof coatings, its importance is self-evident.1 membrane additive function and its application in water-based waterproof coating
1.1 membrane additive function
film additive, also known as coagulant or polysorbant, the agent boiling point is very high, so it is a high boiling point solvent, it will gradually evaporate over time after the film formation. In latex paint, latex particles in the film-forming additives dissolve, its surface will become soft, which can easily lead to polymer particles under pressure to produce deformation, and then fused into a membrane. Adding film-forming additives to water-based waterproof coatings reduces the minimum film-forming temperature of waterproof coatings.
1.2 types of membrane additives and their application
In the current actual situation, the common types of membrane additives are mainly the following: glycol, propylene glycol, ethylene glycol butyl ether, propylene glycol butyl ether, metformin and so on. In general, the latex applied to waterproof coatings has a lower glass transition temperature, i.e. Tg, VAE emulsion Tg is around minus 3 degrees C. Therefore, if the temperature is above 5 degrees C, these lotions can be successfully filmed. Adding film-forming additives to it can provide a significant acceleration effect during film drying. Taking ethylene glycol as a membrane additive as an example, after adding glycol to the water-based coating, the drying time of the coating film will be reduced with the increase of the dose. This shows that for some special waterproofing works, on the basis of ensuring the quality of the project, according to the actual situation can be appropriately added more film additives.2 thickener function and its application in water-based waterproof coating
2.1 thickener function
in water-based waterproof coating, water is its dispersion medium, the consistency is very low, in the vertical wall construction is very hydrate. To solve this problem, it is necessary to work the consistency, appropriately increase the consistency of the coating, and thus change its consistency performance, and thickeners can play an important role in this regard. In the preparation of color paste, the thickener added to it, often can make the viscosity of the grinding slurry increased, play a role in strengthening shearing, greatly promoting the dispersion of pigments. Waterproof coating to achieve a better waterproof effect, its dry film thickness is usually maintained in the range of 1.5 to 2.0mm, the coating has a certain viscosity, in order to ensure that the thickness of each brush in about 0.5mm.
2.2 thickener type and its application
There are four kinds of thickeners that are more common at present, namely cellulose ether, polyacrylate, connective thickener and inorganic thickener. Among them, cellulose ether thickeners are the most common, hydroxyethyl cellulose is one of them. Hydroxyethyl cellulose is powdery, water solubility is very good, as a non-ion thickener, has a very strong consistency, but hydroxyethyl cellulose also has certain disadvantages, that is, easy to grow mold, easy to corruption, and no better leveling. The biggest characteristic of polypropylene esters is the good antibacterial and invasive properties. The thickening mechanism of the ligation thickener and other types of thickeners is different, its molecules have both hydro-friendly and pro-oil parts, the hydro-waterable part can be hydrated and swelled to thicken the water, and the pro-oil part can be contracted with emulsion particle pigment particles to form a mesh structure. In inorgic thickeners, the representative is bento- and bento- and earth. Under normal circumstances, water-based bento-moisturized soil expands after absorbing moisture, gradually forming a denatured gel mineral, which is much larger than when it is not absorbed.3 Desiccant's function and its application in waterproof coatings
3.1 Desticulator's function
desobbizing agent, as the name implies, refers to the elimination of bubbles, to prevent bubbles from negatively affecting the coating film. In waterproof coatings, there are many active agents on the surface, such as emulsifying agents in latex, thickeners in coatings, etc., these active agents are very easy to foam. In the construction process of waterproof coating, if there is foaming phenomenon, it will seriously interfere with the normal construction, thus affecting the quality of the coating film, and eventually lead to the appearance of water seepage. In other words, the appearance of foaming phenomenon, will reduce the performance of waterproof coatings.
3.2 deboulant type and its application
At present, the more common effect is also better desolation agent can be divided into three main categories, one is phosphate-type deblistering agent, the other is mineral oil deblister, and one is silicone-type deblister. First of all, triglyceride phosphate in phosphate desolation agent in the medium and low-grade coating application range is relatively wide, its biggest disadvantage is that the deblistering effect is not ideal. Second, mineral oil deblisters, such as 681F, have better deblistering properties than phosphates, but are lower than silicone deblisters. Then there is the silicone defoiling agent, which is composed of polyether and alkyl chain modified polysilicae, in three types of defoiling agent, its defoiling effect is the best.4 The function of anti-virus, fungicides and their application in waterproof coatings
4.1 anti-virus, antibacterial agent function
waterproof coatings are highly molecular compounds as a base for water-based materials, which are rich in microbial growth elements, in the appropriate environment temperature, microorganisms will reproduce and grow in large numbers, the performance of waterproof coatings change, and thus threaten the quality of waterproof coatings, serious will also cause paint decay and waste. Add anti-virus, fungicides into waterproof coatings, a good solution to this problem: a. anti-virus, anti-bacterial agent can inhibit the production of energy; b. anti-virus, anti-bacterial agent can interfere with the biological formation of pathogens; c. anti-virus, anti-bacterial agent can destroy the integrity of cell structure.
4.2 Types of anti-virus, fungicides and their applications
In the current waterproof coating additives, a variety of more common are such categories: heterocyclic compounds, amine compounds, substitute aromatics, organic metal compounds and other major categories. It is important to note that organic mercury broad-spectrum anti-mold agents have been banned because of their great harm to humans.5 Conclusion
In short, the water-based waterproof coating system is very complex, additives as an important part of the system, although the dose is not much, but the performance of waterproof coating can play a crucial role. Therefore, in the development and production of water-based waterproof coatings, can be increased by different doses of additives to carry out experiments, so as to provide a strong reference for subsequent construction practice..