How to improve the water resistance of waterborne epoxy coatings

As a high-performance, high-value-added adhesive, epoxy resin adhesive is highly valued by the industry, but at the same time, counterfeit and shoddy products are often patronized. Therefore, we can identify it by the following chemical methods. Method 1:

The sample is dissolved in sulfuric acid, and then concentrated nitric acid is added, and a large amount of sodium hydroxide solution is poured into it. The second type: drop 5 drops of concentrated nitric acid on the resin adhesive film, move the reactant into the test tube after a few minutes, add 6ml of acetone and then add potassium hydroxide ethanol solution to make it alkaline, if it turns from red to purple, it indicates that it contains epoxy resin glue containing bisphenol A type, this method is also intuitive; Method 3:

Take the adhesive film or glue solution, p-phenylenediamine and 8ml of sample water, boil for 8min, if it is epoxy resin, the solution is peach....

Composition of coatings: film-forming substances (binders), pigments and fillers, solvents, additives;

The water resistance mainly depends on the binder, so the key to improving the water resistance of water-based epoxy coatings is to choose an excellent water-based epoxy resin and water-based epoxy curing agent.

Summary. Epoxy resin is an organic compound that contains two or more epoxy groups in the molecule, and their relative molecular mass is not high except for a few individuals. The molecular structure of epoxy resin is characterized by the presence of active epoxy groups in the molecular chain, which can be located at the end, middle or in a cyclic structure of the molecular chain.

Because the molecular structure contains active epoxy groups, they can be cross-linked with various types of curing agents to form insoluble polymers with a three-way network structure. All polymer compounds containing epoxy groups in their molecular structure are collectively referred to as epoxy resins. The cured epoxy resin has good physical and chemical properties, it has excellent adhesion strength to the surface of metal and non-metallic materials, good dielectric properties, small variable shrinkage, good dimensional stability of products, high hardness, good flexibility, and stability to alkali and most solvents, so it is widely used in various departments of national defense and national economy for pouring, impregnation, laminating materials, adhesives, coatings and other uses.

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Hello, the ratio is epoxy resin 100, carbon black 2-5, alumina powder 25, etc., see the figure below.

Epoxy resin is an organic compound that contains two or more epoxy groups in the molecule, and their relative molecular mass is not high except for a few individuals. The molecular structure of epoxy resin is characterized by the presence of active epoxy groups in the molecular chain, which can be located at the end, middle or in a cyclic structure of the molecular chain. Because the molecular structure contains active epoxy groups, they can be cross-linked with various types of curing agents to form insoluble polymers with a three-way network structure.

All polymer compounds containing epoxy groups in their molecular structure are collectively referred to as epoxy resins. The cured epoxy resin has good physical and chemical properties, it has excellent adhesion strength to the surface of metal and non-metallic materials, good dielectric properties, small variable shrinkage, good dimensional stability of products, high hardness, good flexibility, and stability to alkali and most solvents, so it is widely used in various departments of national defense and national economy for pouring, impregnation, laminating materials, adhesives, coatings and other uses.

Ethylenediamine, triethanolamine or triethylenetetraamine in epoxy curing agent are miscible with water, and aromatic amines such as dicyandiamine, m-phenylenediamine, N,N-dimethylaniline are slightly soluble in water and have better solubility resistance.

Water-based epoxy resin refers to a stable dispersion system in which epoxy resin is dispersed in the form of particles or droplets in a dispersion medium with water as a continuous phase. Because epoxy resin is a thermosetting resin with linear structure, water-based epoxy curing agent must be added before construction, and chemical cross-linking reaction occurs at room temperature. In addition to the many advantages of solvent-based epoxy resin coatings, water-based epoxy resin coatings are:

Reasonable selection of epoxy resin substrate, Guxiao Selling roughening agent and various modifiers and additives can prepare water-based epoxy resin coatings with different properties. The multi-performance characteristics of waterborne epoxy resin coatings determine that they have a wider application prospect than solvent-based or solvent-free epoxy resin coatings. At present, the application of waterborne epoxy resin coating mainly includes the following aspects:

The first is floor coating, which can be used as a high-performance environment-adaptable floor coating to replace solvent-based epoxy resin coatings, and can also be mixed into cement mortar as a polymer component to make high-performance polymer mortar floor materials; The second is the wooden floor coating, which can be used as a varnish for wooden flooring, replacing the solvent-based polyurethane crystal floor paint widely used in the market.

Hello, I am happy to serve you and give you the following answers: waterborne polyurethane and water-based epoxy resin blend generally have good weather resistance, but it will also be affected by the external environment, if the temperature is too high or the humidity is too large, it will affect the weather resistance. In general, waterborne polyurethane and waterborne epoxy resin are blended with good weather resistance, but if the temperature is too high or the humidity is too high, it will affect the weather resistance.

Solution: 1. First of all, the ambient temperature and humidity should be controlled, and the temperature and humidity should be kept within the appropriate range to ensure that the water-based polyurethane and water-based epoxy resin are blended with good weather resistance. 2. Secondly, the appropriate coating should be selected, and the weather resistance of the coating will also affect the weather resistance of water-based polyurethane and water-based epoxy resin, so we should choose a Xiaoshi coating with good weather resistance.

3. Finally, attention should be paid to the construction process, which will also affect the weather resistance of waterborne polyurethane and water-based epoxy resin, so we should pay attention to the construction process to ensure that the water-based polyurethane and water-based epoxy resin are blended with good weather resistance. Personal experience: waterborne polyurethane and water-based epoxy resin blend generally have good weather resistance, but it will also be affected by the external environment, so attention should be paid to controlling the ambient temperature and humidity, choosing the appropriate coating, and paying attention to the construction process to ensure that the water-based polyurethane and water-based epoxy resin blend has good weather resistance.

The difference between modified epoxy resin waterproof coating and permeable epoxy resin waterproof coating: The difference between pro-modified epoxy resin waterproof coating and permeable epoxy resin waterproof coating is that epoxy resin is made of chemical raw materials, and waterproof coating is made of waterproof coating. The difference between modified epoxy resin waterproof coating and permeable epoxy resin waterproof coating is that epoxy resin is made of chemical raw materials, and waterproof coating is made of waterproof coating.

Definition of High Permeability Modified Epoxy Coating and Chemical Grouting Material High permeability modified epoxy material is not a coating or chemical grouting material with general permeability, but refers to a coating that can penetrate into C50 high-grade concrete for more than 2mm after brushing, and can form a consolidated reinforcement layer or can be poured into the mud layer with a permeability coefficient of k=(10 6 10 8) cm, so that the "soil" quality becomes a "rock" quality chemical grouting material.

Waterborne epoxy coatings have the following advantages:

1) Water as the dispersion medium, no organic solvent or low content of volatile organic compounds, no environmental pollution, no fire hazard; meet current environmental protection requirements;

2) Good operation performance, construction tools can be directly cleaned with water, safe and convenient operation;

3) It has good adhesion to most substrates, and can be used with cement or cement mortar;

4) It can be cured in room temperature and humid environment, with a reasonable curing time, and ensure a high cross-linking density.

5) It can be mixed with other water-based polymer systems to make up for each other in terms of performance.

1) The heat of evaporation of water is high compared to organic solvents, which requires another means to help the evaporation of water. Under the conditions of low temperature and high humidity, the evaporation of water is more invasive, which prolongs the surface drying time.

2) The surface tension of water is high, which causes difficulties in the wetting of substrates and pigments and fillers, especially the substrate with unclean degreasing, and it is necessary to add substrate wetting agent to improve the wettability of water-based epoxy resin coating on the substrate;

3) The dispersion stability of pigments and fillers in water-based epoxy coatings is worse than that of solvent-based coatings, and it is easy to aggregate and precipitate;

4) The conductivity of water is high, which is easy to corrode the metal, and the flash erosion problem that occurs in the drying process of the coating film can be solved by using flash corrosion inhibitors and active pigments.

1) The heat of evaporation of water is high compared to organic solvents, which requires another means to help the evaporation of water. Under the conditions of low temperature and high humidity, the evaporation of water is more invasive, which prolongs the surface drying time.

2) The surface tension of water is high, which causes difficulties in the wetting of substrates and pigments and fillers, especially the substrate with unclean degreasing, and it is necessary to add substrate wetting agent to improve the wettability of water-based epoxy resin coating on the substrate;

3) The dispersion stability of pigments and fillers in water-based epoxy coatings is worse than that of solvent-based coatings, and it is easy to aggregate and precipitate;

4) The conductivity of water is high, which is easy to corrode the metal, and the flash erosion problem that occurs in the drying process of the coating film can be solved by using flash corrosion inhibitors and active pigments.

It has extremely high adhesion to the substrate, excellent corrosion resistance and chemical resistance of the cured coating film, small shrinkage of the coating film, high hardness, good wear resistance and excellent electrical insulation performance. Using water as a dispersed medium, it saves energy, is pollution-free, and meets the requirements of environmental protection.

1) Water as the dispersion medium, does not contain toluene, xylene and other volatile organic solvents, will not cause environmental pollution, no hidden danger of fire, to meet the current environmental protection requirements, of course, a small amount of propylene glycol methyl ether and other non-air pollution alcohol ether solvents can be added to improve the film formation of water-based epoxy coatings.

2) It can be applied and cured in a humid environment, with a reasonable curing time, to ensure that the coating film has a high cross-linking density.

3) It has good adhesion to most substrates, even on the surface of wet substrates.

4) Good operation performance, construction tools can be directly cleaned with water, can be reused, the preparation and construction operation of paint is safe and convenient.

5) The cured coating film has a soft luster, good texture, and good anti-corrosion performance and unidirectional air permeability. The general floor coating is especially suitable for construction in humid environments, such as underground parking lots, canteens and other wet floors.