How to eliminate the phenomenon of paint bubbles, and why do bubbles appear when spraying paint?

Water-based paints. As the name suggests, water is used as a solvent or dispersion medium to add various binders, pigments, and defoamers.

It is prepared with additives such as thickeners and film-forming agents. Among them, defoamer is also one of the important components, because the foaming of the paint will affect the production of canning, and the foaming of the paint will cause the eye of the needle.

Shrinkage porosity is a construction defect. Therefore, in the process of preparation of water-based coatings, a certain amount of coating defoamer will be added, which plays a role in eliminating foam and inhibiting foam regeneration.

Due to its own characteristics, water-based coatings have high requirements for the surface state of the coating film and high requirements for construction performance. If there are air bubbles in the paint, it will reduce production efficiency and cause defects in the coating film. Generally, water-based paint blistering is mainly due to the following reasons.

1. Blistering during production: stirring will be carried out during production because the coating production formula contains a variety of additives, which contain surfactants.

It is easy to foam when stirring.

2. Blistering during the curing process: During the curing process of the coating, gas is generated during the reaction, resulting in blistering.

3. Blistering during construction: In the process of construction, the coating film has high temperature and too much absorption, which is easy to blister; The way it is brushed causes blistering.

In order to avoid foaming problems in water-based coatings, suitable paint defoamers can be added during production or use.

Foam can be eliminated and controlled in time. Avoid adverse effects caused by foam.

In the case of paint foam, you can find a professional defoamer manufacturer to provide defoaming solutions, professional manufacturers for the water-based paint production process and construction characteristics, for the research and development of paint defoamer, defoaming, foam inhibition effect is good, will not produce construction defects.

Most of the agent varieties belong to surfactants.

can change the surface tension of the coating.

As a result, there are internal factors that make the paint itself easy to blister or stabilize the foam.

The paint manufacturing process requires the use of a variety of high-speed mixers, such as three-roller machines, sand mills, and ball mills. Various methods and methods used in paint coating, such as air spraying, airless spraying, roller coating, flow coating and spray coating. In these processes, the free energy of the coating system is increased to varying degrees, helping to produce foam, which is an external factor that produces foam.

Water-based latex coatings in the coating industry.

The foam problem is the most prominent, which is caused by its special formula and special production process.

1) Latex paint.

It is used as a diluent with water, and a certain amount of emulsifier must be used when the emulsion is polymerized.

In order to produce a stable aqueous dispersion. The use of emulsifiers leads to a significant reduction in the surface tension of the emulsion system, which is the main cause of foaming.

2) Wetting agent and dispersant of dispersed pigments in latex paint.

It is also a substance that reduces the surface tension of the system, which contributes to the formation and stability of foam.

3) The low viscosity of latex paint is not easy to construct, and the use of thickener will thicken the film wall of the foam and increase its elasticity, so that the foam is stable and not easy to eliminate.

4) Extraction of free monomers during the production of emulsion; Adjustment, dispersion and stirring when preparing latex paint; Spraying, brushing, rolling and other operations on the construction process. All of these can alter the free energy of the system to varying degrees, prompting the creation of bubbles. The foam problem of latex paint makes the production operation difficult, and the air in the foam will not only hinder the dispersion of pigments or fillers, but also make the utilization rate of the equipment insufficient and affect the output; Due to foam during canning, it needs to be filled many times.

The air bubbles left on the paint film during construction cause surface defects, which not only damage the appearance, but also affect the anti-corrosion and weather resistance of the paint film.

In the coating industry, the surface tensiometer is used as a measuring instrument to measure the tension of the coating surface, eliminate the bubbles of the coating product, and provide a lot of data support for improving the surface filling process of the coating product.

1. The reason for bubbles in paint spraying.

Leakage is sent 1, this may be a problem that has been overlooked, there is water in the trachea, and it enters the coating system when spraying, because it is incompatible, so there are a lot of bubbles, and the defoamer has no effect probably because of the problem of water.

2. When adjusting the gun, the amount of paint is too large, the airflow is too large, resulting in thick coating, and there is splashing in the later stage, so bubbles are easy to appear.

3. There is a problem with the formula system, 1000cp is a very low viscosity, and bubbles will appear if there are incompatible components in the system.

4. The viscosity of the paint is too high, the coating is thick at one time, the wood conduit is thick and deep, and the filling hole contains air; The spray air pressure is too high, and too much air is mixed into the paint.

5. Oil, dust, sweat, etc. are attached to the surface of the coating, and moisture is gathered around these impurities.

6. The temperature difference between the paint and the coated surface is too large.

7. Improper use of thinner, excessive addition of curing agent or wrong use of curing agent.

8. The temperature of the coating environment is too high or the relative humidity is too high.

9. If the return to the lower coating is not completely dry, the upper coating will be applied, and the upper coating will dry rapidly.

10. When the heating and drying coating is used, the temperature is too high, the standing time before the coating is heated is not enough, the solvent is not fully volatilized, the paint itself brings bubbles, and the bubbles generated during stirring are not eliminated, etc.

Second, the method of eliminating air bubbles.

It's normal to have bubbles, but they can all be adjusted to have no bubbles or fast defoaming. If the effect of adding defoamer is not great, you can try it with another resin, and the viscosity of the resin is too high.

Also pay attention to the compatibility of defoamer and leveling agent. The most difficult thing is the use of defoamer, you can use a measuring cylinder, pour the paint after high-speed stirring into the graduated cylinder, and the defoaming effect after a few minutes. Try more experiments yourself, and you will definitely find the reason.

Cause: Gases (solvent vapor, water vapor, expanded air or other gases that can be mixed into the paint such as carbon dioxide, etc.) break through the coating and bulge to form bubbles, which then crack or wear out to form pinholes. When the drying rate of the surface layer of the coating is slightly higher than that of the inside, when the surface layer has begun to condense and the internal solvent or air continues to evaporate, it will break through the surface layer of the coating to form bubbles.

This is related to the following conditions: the viscosity of the paint is too high, it is thick at one time, the wood conduit is thick and deep, and the filling of the hole is not real and contains air; The spray air pressure is too high, and too much air is mixed into the paint. Oil, dust, sweat, etc. are attached to the surface of the coating, and moisture accumulates around these unclean objects; The temperature difference between the paint and the surface to be painted is too large; Improper use of diluent, excessive addition of curing agent or use of the wrong curing agent; The ambient temperature or relative humidity of the coating environment is too high; If the drying of the lower coating is not complete, the upper coating will be applied, and the upper coating will dry rapidly; When the coating is heated and dried, the temperature is too high, the standing time before the coating is heated is not enough, the solvent is not fully volatilized, the paint itself brings air bubbles, and the air bubbles generated during stirring are not eliminated, etc. - The answer is a reference to "Golden Pegasus Paint".

Hello! We're happy to answer your questions. The reasons why the paint has bubbles are as follows:

1) The substrate treatment is not up to standard, such as the high moisture content of the wood, or the pine resin and the aromatic oil contained in the wood itself are not removed, which will lead to blistering when it volatilizes from Zheng Ran. (2) Apply the finishing layer when the oily or water-based putty is not completely dry or the primer is not dry. (3) The joints and holes of the wood are not filled, and there are voids and holes.

4) The paint viscosity is too high. (5) Improper paint ratio. (6) Drag the brush back and forth while brushing, and the air bubbles generated are not eliminated.

7) Oil, dust, blisters, etc. are attached to the surface of the substrate, and water is stained around these impurities. (8) There is water in the compressor and air pipe, or water splashes on the construction surface. <>

Due to the loss of local adhesion, the wall coating separates the paint film from the surface of the substrate and causes blistering.

Possible causes: 1. Apply oil-based paint on a damp and not dry substrate.

2. Moisture seeps into the room through the exterior wall. This generally does not happen with latex paints.

3. Soon after the latex paint dries, the paint film is exposed to high humidity, especially when the surface treatment is not thorough.

Solution: 1. If the blisters are not fully extended to the substrate: remove them by scraping with a scraper, then polish them with fine sandpaper, then rinse them with clean water, and repaint them with high-quality interior wall latex paint after drying.

To drive away moisture, scrape with a scraper to remove air bubbles, then polish with fine sandpaper, then rinse with water, wait to dry, apply a layer of sealing primer, and then brush the topcoat.