Is there always a problem with the coating when recoating? It turns out that choosing the right leveling agent can save so much trouble!

Is there always a problem with the coating when recoating? It turns out that choosing the right leveling agent can save so much trouble!

In scenes such as decoration, furniture renovation or industrial product coating, recoating is a common operation. However, many people encounter various difficult problems when recoating, such as orange peel, pinholes, shrinkage holes on the coating surface, or uneven gloss and poor adhesion after the coating dries. The emergence of these problems not only affects the appearance, but also may reduce the protective performance of the coating and shorten the service life. In fact, in many cases, choosing the right leveling agent can easily solve these troubles and make recoating more effective.

Leveling agent: "beautician" of the coating surface

Leveling agent is an additive that can improve the construction performance of the coating and make the coating surface smooth and smooth. After the coating is applied, the coating surface is prone to unevenness due to factors such as the surface tension and viscosity of the coating. The leveling agent is like a skilled "beautician". It can reduce the surface tension of the coating, make the coating spread better on the surface of the substrate, fill the traces and defects left during construction, and thus form a flat and smooth coating.

From a microscopic point of view, during the drying process of the paint, the surface tension will cause the molecules in the paint to gather to the surface, causing the surface to shrink. Without the effect of the leveling agent, this shrinkage will form an irregular texture, such as orange peel. The leveling agent molecules can form a uniform film on the surface of the paint, reduce the surface tension gradient, and enable the paint to flow and spread evenly, avoiding the occurrence of these problems.

Common recoating problems and countermeasures for leveling agents

Orange peel phenomenon

Orange peel is one of the common problems when recoating. It will make the coating surface present an uneven texture similar to orange peel, which seriously affects the appearance. This is mainly caused by reasons such as excessive viscosity of the paint, improper spray gun pressure during construction, or too fast drying speed.

Choosing a suitable leveling agent can effectively solve the orange peel problem. For example, some silicone leveling agents have a good ability to reduce surface tension, which can enable the paint to spread quickly on the surface of the substrate and reduce surface shrinkage. When recoating, adding an appropriate amount of silicone leveling agent to the paint can reduce the surface tension of the paint, make the coating surface smoother, and avoid the occurrence of orange peel phenomenon.

Pinholes and craters

Pinholes are small holes on the surface of the coating, while craters are small depressions on the surface of the coating. These problems usually occur because air, water, or impurities such as oil and dust are mixed into the coating, which prevents the coating from spreading evenly during the drying process.

Leveling agents can help the coating better wet the surface of the substrate and remove air and impurities. Some acrylic leveling agents have good wetting and leveling properties. They can form a wetting film between the coating and the substrate, allowing the coating to adhere better to the substrate and promote the removal of air and impurities. Before recoating, make sure the surface of the substrate is clean, and then add an appropriate amount of acrylic leveling agent to the coating to effectively reduce the appearance of pinholes and craters.

Uneven gloss

Uneven gloss will cause the coating surface to present different light and dark areas, affecting the overall visual effect. This may be due to poor leveling of the coating, resulting in uneven coating thickness, or the coating is affected by environmental factors such as temperature and humidity changes during the drying process.

Leveling agents can improve the leveling of the coating and make the coating thickness more uniform. At the same time, some leveling agents also have the function of adjusting the drying speed of the coating, which can reduce the impact of environmental factors on the gloss of the coating. For example, fluorocarbon leveling agents can not only reduce surface tension and improve leveling, but also adjust the drying speed of the coating to a certain extent, so that the coating can maintain a uniform gloss under different environments.

Poor adhesion

Poor adhesion can cause the coating to peel and peel easily, reducing the protective performance of the coating. This may be due to improper surface treatment of the substrate or poor compatibility between the coating and the substrate.

Leveling agents can enhance the adhesion between the coating and the substrate. Some leveling agent molecules contain functional groups that can react chemically with the surface of the substrate, which can form chemical bonds between the coating and the substrate, thereby improving adhesion. When recoating, choose a leveling agent with good adhesion and ensure that the substrate surface is properly treated, such as polishing, cleaning, etc., which can effectively improve the adhesion of the coating.

How to choose a suitable leveling agent

Consider the type of coating

Different types of coatings have different requirements for leveling agents. For example, water-based coatings usually need to choose leveling agents with good compatibility with water, such as water-based silicone leveling agents, water-based acrylic leveling agents, etc.; while solvent-based coatings can choose solvent-based silicone leveling agents, fluorocarbon leveling agents, etc.

Pay attention to the construction process

The construction process will also affect the selection of leveling agents. If it is spraying, it is necessary to choose a leveling agent that can quickly reduce the surface tension and promote the atomization and spreading of the coating; if it is brushing or roller coating, it is necessary to choose a leveling agent with good wettability and leveling properties to ensure that the coating can be evenly applied to the surface of the substrate.

Reference environmental conditions

Environmental conditions such as temperature and humidity will also affect the drying and leveling of the coating. In a high temperature and dry environment, it is necessary to choose a leveling agent that can slow down the drying speed of the coating and improve the leveling property; in a low temperature and humid environment, it is necessary to choose a leveling agent that can promote the drying of the coating and prevent sagging.

Conduct a small sample test

When selecting a leveling agent, it is best to conduct a small sample test first. Add different types and amounts of leveling agents to the paint, conduct construction tests, observe the leveling effect, glossiness, adhesion and other performance indicators of the coating, and then select the most suitable leveling agent and dosage.

It is not terrible to have problems with the coating during recoating. As long as you choose the right leveling agent, you can easily solve various problems. The leveling agent is like a silently dedicated "behind-the-scenes hero". Although it is not eye-catching, it can bring a flat, smooth and beautiful surface to the coating and improve the performance and quality of the coating. When recoating, you may wish to spend more time to choose the right leveling agent to make your coating work smoother and the effect more outstanding.