The relationship between film formation and MFFT of waterborne coatings This week, Mr. Li asked us three questions through our questioning water-based paint expert column. This is the second problem: Problem: Film formation above MFFT, no film formation below MFFT, what happens during above or below the MFFT, resulting in film formation? Above MFFT, the emulsion particles are soft and hard below. This phenomenon is associated with glass transition.

Waterborne two-component paint seeds and loss of light - ask water-based paint experts Question: Hello! I have two problems with the double-surface water-based topcoat. One is that when the film is thick, it is easy to produce rash [related to defoaming agent or related to water and curing agent to produce CO2?]. One is a double component. After mixing for 2 hours, it will lose light. What is the reason? Is there a solution? Thank you. Answer: Our team of experts has had a heated discussion about your issue. Because we don't know your specific formula, we only guess based on the phenomenon you describe. Our experts have different opinions about your issue. We will now hand over the views of all the parties we have collected, and we hope to have a multi-faceted reference value for you. View 1: The seedsphenomenon that occurs when you encounter a thick film in a two-component water-based topcoat is due to the "Bernard vortex" phenomenon. Specifically, the solvent in the aqueous resin or the aqueous formulation system is not coordinated during the volatilization process. When the gas is generated, the surface of the paint film is dried and the gas is not discharged, so that dark bubbles or scorpions are formed below the paint film. To solve this problem, you need to adjust the recipe structure, especially to adjust the drying process of the recipe: 1. Pay attention to the drying speed of the resin itself 2. Pay attention to the coordination of additives 3. Pay attention to the choice of surface desiccant As for your second question, this is due to the mismatch between the crosslinker and the resin and other additives in the formulation, and the cross-linking reaction is not normal. It is recommended to adjust the formulation structure and pay attention to the type and amount of additives. View 2: Question 1, if this phenomenon occurs only in thick film, it is likely that it is not caused by the problem of surface tension, that is, it is not necessarily the problem of defoaming. You can use a coating that avoids bubbles, such as scraping, to confirm. Question 2, the two-component system has a certain period of use. After mixing the two components, the reaction starts in the prevention process, the molecular weight increases, and even cross-linking occurs. Intermolecular infiltration is affected during film formation, and it is impossible to form a microscopically flat film, which is macroscopically loss of light. The first and second questions add up to look like you should use better quality resins and crosslinkers. Sinograce Chemical produces water based coating,Water-based glue, polyurethane coating,Acrylic solution. visit us sinograce chemical: https://www.sinogracechem.com Get a Quote Now :sales@sinogracechem.com Telephone               :+86 0551 63459511

Filming aids in waterborne coatings Problem : Why do you need to add filming aids to one-component waterborne coatings? The emulsion alone does not form a film. Filming aids are added to form a film. Why does the film-forming auxiliary volatilize, which is still a complete film, and is different from a film without a filming aid? Why can't a single emulsion be fused by water to produce a capillary pressure fusion film? Response: Film forming auxiliaries are not required for all emulsion film formation. These additives are only required for those resins that require higher hardness after film formation.ecause the emulsion particles of these resins are relatively hard and their self-flowability is not good, even if the capillary pressure (surface tension) you mentioned is not enough to fuse the particles, the polymer chains penetrate each other and form a molecular level.Continuous film.Water in these systems is only a dispersing medium and does not have the plasticizing effect of softening resin particles. In Sinograce chemcal's resin system, fast drying nano-scale waterborne acrylic resins, high adhesion aqueous acrylic emulsions and high solid aqueous aliphatic polyurethane dispersions do not require a filming aid. High-hardness water-based acrylic emulsions, self-crosslinking acrylic emulsions, etc., require the use of a film-forming aid in the formulation to aid film formation. visit us sinograce chemical: https://www.sinogracechem.com Get a Quote Now :sales@sinogracechem.com Telephone               :+86 0551 63459511

Is the black spot on the surface of the water-based paint mildew? - Ask the water-based paint expert Problem: The wooden doors of our company's surface veneer have no black spots before they are painted. After spraying the water-based paint (primer + top coat), black spots appear on the veneer during the natural drying process. I wonder if the water-based paint is mildewed? If the oil-based colorant is used to seal the bottom, will the water-based primer finish avoid such problems? Response： According to your description and photo analysis, the phenomenon you are experiencing is not the mildew of the waterborne wood, but the chemical substrate of the wood substrate you use. This is because there is no black spot in the wood. This is the case when the wood is unevenly colored, and when it is dry, it will be swollen with water or the solution will swell. Most wood is chemically treated. Black spots do not occur when the chemical treatment is good. However, in some cases, such as excessive hydrogen peroxide accumulation or unidentified stains, there will be black spots on your picture. We recommend that you try to wash the surface of the wood with water or sprinkle, and then dry the paint. We feel that after solving the problem that the substrate is not clean, the problems you encounter can be solved. For wooden doors that have been painted, only remove the paint and clean it. Sealing the bottom with an oily colorant and applying a waterborne primer finish may not solve your problem. This still depends on the substrate. If the substrate is not clean, black spots may occur, but the solvent has little effect on the fiber, and the black spots are not so obvious. I hope our answer will help you. If you have more specific requirements, you can contact us directly. For more information on waterborne coatings, you can also visit sinograce chemical's waterborne coatings knowledge base and recipes in our waterborne formula library. Or ask us directly through our question water-based paint expert column. Sinograce Chemical produces water based coating,Water-based glue, polyurethane coating,Acrylic solution. visit us sinograce chemical: https://www.sinogracechem.com Get a Quote Now :sales@sinogracechem.com Telephone               :+86 0551 63459511