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Emulsion selection for polymer cement waterproofing emulsion
1.2 Selection of Different Types of Emulsions
1.2.1 Select the emulsion according to the adhesion, compactness and water resistance of the coating
JS waterproofing emulsion can be divided into two categories: one is a non-reactive polymer, such as neoprene latex, butyl latex, vinyl acetate copolymer emulsion, etc. In the composite structure, the polymer film covers the surface of the cement gel Or cement hydrates fill between the polymer networks. Organic and inorganic materials are only inert and mechanically filled with each other. In this type of waterproofing emulsion, the adhesion, compactness, and water resistance of the coating are relatively poor. The other type is a reactive polymer in two reaction forms: one is a cross-linking curing reaction between polymers (or with a hardener) to form macromolecules; the other is a polymer reactive group Chemical reactions occur with the cement hydration products, forming an interfacial structure that is chemically bonded to enhance the performance of the material through the interface. Through appropriate modification processes, the chemical bonding of polymer and cement hydration products can be greatly enhanced.
Studies have shown that the modified acrylic copolymer emulsion can react with cement hydration-innate Ca(OH): a naturally-occurring ion-bonded macromolecular network interweaving structure, and the degree of hydration increases with the age of hydration. The greater the amount of this reactionary creature. A polymer containing a functional group such as COOH can interact with Ca+ in the cement hydration product, thereby significantly improving the strength and water resistance of the material.
1.2.2 Select emulsion according to weather conditions
The different weather conditions also have different requirements for low temperature flexibility of JS waterproofing emulsions. For example, in southern China, the waterproof temperature of the roof can meet the requirement of -10°C, while in the northern region, the requirement of low temperature resistance of -20°C can meet the waterproof requirements of the roof. In general, the glass transition temperature of the polymer emulsion for js waterproofing emulsion in the southern region is higher than that in the northern region.
1.2.3 Select Emulsion from Monomer Analysis of Emulsion
Acrylic vinegar emulsion from the monomer structure, its water resistance, weather resistance and flexibility are good; and VAE emulsion from the monomer composition, because it contains about 85% of vinyl acetate, the molecular polarity is relatively large, Water resistance is poor. Therefore, from the standpoint of monomer composition alone, acrylic vinegar-based emulsions are more waterproof than VAE emulsions and have a certain advantage in terms of water resistance and weather resistance.
1.2.4 Select emulsion according to the role of emulsion and cement
Acrylic vinegar emulsion itself is soft, its high elongation, less active groups, and the role of cement is also less, so you can use more cement and other powder. The disadvantage is that it is more difficult to achieve a tensile strength of 2.0 MPa or more, and at the same time, the elongation at break is difficult to reach more than 200%. It is also due to the fact that the active groups are few, and the effect point of the cement is little, so it is not suitable for high-strength rigidity. waterproofing emulsion. The VAE emulsion uses a large amount of polyvinyl alcohol as a protective body, and together with the activity of vinyl acetate itself, there are many points of action with cement. Therefore, manufacturers use cement-based waterproofing emulsions to reduce the formulation of cement and other fillers.
1.2.5 Select Emulsion According to Different Usage of 1S waterproofing emulsion
JS waterproofing emulsion uses different parts, and its choice of emulsion is also different. For example, the roof waterproofing coating must have excellent UV aging resistance, while the water resistance requirement is relatively low, but it must meet the requirements of intermittent water resistance and anti-water retention; and the toilet waterproofing emulsion, generally does not require anti-ultraviolet and anti-aging, but water resistance Sex must meet intermittent water resistance and high water resistance. Acrylic vinegar polymer emulsion molecules do not contain C = C unsaturated bond, the molecule is relatively stable, not subject to external thermal energy, ultraviolet light, ozone degradation and degradation caused by aging materials, and cement hydration products also have superior anti-aging properties. The VAE emulsion is a linear polymer material, the molecule does not contain reactive functional groups, cross-linking is difficult, resulting in low molecular bond energy, under the influence of external energy such as heat or ultraviolet radiation, some of the molecular bonds are easy to break, causing molecular degradation, so that The coating film becomes brittle, hard, and cracked, and thus its UV resistance and aging resistance are poor. In addition, the vinyl acetate structure has a strong polarity, resulting in poor alkali resistance.
2 Conclusion
JS waterproofing emulsion has outstanding waterproof effect, short construction period, low cost, and convenient and safe to use. It is generally welcomed by construction management and construction design and construction units. A JS waterproofing emulsion with good performance lies in the correct selection of polymer emulsions, cements, additives and construction processes. Strengthen the research, summary and construction application practice of JS waterproofing emulsion, and the material will be more applied.

Read more at http://acrylicsemulsion.pressbooks.com/chapter/emulsion-selection-for-polymer-cement-waterproofing-emulsion/ .