Application of PU leveling agent
PU leveling agent, as a key coating additive, plays a vital role in the coating industry. It not only affects
the construction performance of the coating, but is also directly related to the quality
and aesthetics of the coating film.
1. Basic knowledge of PU leveling agent
PU leveling agent, also known as surfactant, is a chemical substance that can significantly reduce the
surface tension of the coating. It is usually added to the coating system to improve the
fluidity and leveling of the coating. By adjusting the surface tension of the coating, the PU leveling agent
can eliminate the surface tension gradient, allowing the coating to spread and flow
better on the substrate, thereby forming a flat, smooth and uniform coating film.
2. The working principle of PU leveling agent
The working principle of PU leveling agent is mainly reflected in the following aspects:
Reducing surface tension:
PU leveling agent can effectively reduce the tension on the surface of the coating and improve the wettability
and fluidity of the coating. This allows the coating to better penetrate into the tiny pores of the substrate and
enhance the bonding between the coating and the substrate.
Improve leveling: By adjusting the surface tension gradient of the coating, the PU leveling agent can eliminate
various defects of the coating during the film forming process, such as scratches,
orange peel, water marks, shrinkage and pinholes. These defects not only affect the aesthetics of the coating,
but may also reduce the protective performance of the coating.
Improve gloss and smoothness: The PU leveling agent can make the coating form a surface with gloss and
smoothness after drying and film forming. This can not only improve the decorative
effect of the coating, but also enhance the wear resistance and weather resistance of the coating.
Adjust the drying speed:
Some PU leveling agents (such as solvent-based leveling agents) can affect the drying speed of the coating
by adjusting the viscosity and leveling time of the paint
film. This helps to better control the drying and curing process of the coating during the coating construction process.
3. Types of PU leveling agents
According to different chemical structures, PU leveling agents can be divided into many types, mainly including:
Organosilicon leveling agents: This type of leveling agent can significantly reduce the surface tension of the coating
and improve the wetting ability and fluidity of the substrate. Among them,
polydimethylsiloxane and its modified products are the most widely used silicone leveling agents.
Acrylic leveling agents:
Acrylic leveling agents usually have excellent compatibility and stability, which can improve the fluidity and
leveling of coatings, while improving the gloss and wear resistance of coatings.
Fluorocarbon leveling agents:This type of leveling agent has extremely low surface energy and can significantly
improve the stain resistance and weather resistance of coatings. However, due
to its high cost, the application of fluorocarbon leveling agents is relatively limited.
4. Application of PU leveling agents in coatings
PU leveling agents are widely used in various coating systems, especially in polyurethane coatings. The following
are several main application scenarios of PU leveling agents in coatings:
Automotive coatings:
In automotive coatings, PU leveling agents can significantly improve the fluidity and leveling of coatings,
eliminate various defects on the surface of the coating, and
improve the gloss and smoothness of the coating. At the same time, it can also enhance the bonding between the
coating and the substrate, and improve the durability and scratch resistance
of the coating.
Wood coatings:
In wood coatings, PU leveling agents can improve the wettability and permeability of the coating, allowing the coating
to better penetrate into the tiny pores of the wood. This can not only improve the bonding strength between the coating
and the wood, but also enhance the wear resistance and weather resistance of the coating.
Industrial coatings: In industrial coatings, PU leveling agents can significantly improve the construction performance
and coating quality of the coating. It can make the coating spread and flow
better on the substrate to form a flat and smooth coating. At the same time, it can also enhance the stain resistance and
weather resistance of the coating and extend the service life of the coating.
5. Precautions
When using PU leveling agents, you need to pay attention to the following points:
Dosage control:
The dosage of PU leveling agent should be controlled within a certain range. Excessive dosage will cause the viscosity
of the coating to drop too much, resulting in excessive
leveling (such as sagging and flowing), affecting the quality of the coating. If the dosage is too small, it cannot be evenly
distributed in each part of the coating, resulting in defects such as
insufficient leveling and shrinkage.
Compatibility:
PU leveling agent should have good compatibility with the coating system. If the compatibility is poor, it may cause
defects such as delamination and cracking in the coating.
Construction conditions:
When using PU leveling agent, pay attention to the influence of construction conditions. Factors such as temperature, humidity,
and wind speed may affect the fluidity
and leveling of the paint. Therefore, the construction conditions should be fully understood before construction, and corresponding
measures should be taken to adjust them.
In summary, PU leveling agent, as a key coating additive, has broad application prospects in the coating industry.
By understanding its basic knowledge and working principles, as well as
mastering its application skills and precautions in coatings, we can better use PU leveling agent to improve
the construction performance and coating quality of coatings.
