PU leveling agent: the secret of leveling in the coating industry
In the coating industry, leveling agent is an indispensable auxiliary agent, and PU (polyurethane)
leveling agent plays an important role in various coating systems with its unique properties.
1. Basic knowledge of PU leveling agent
PU leveling agent, full name polyurethane leveling agent, is a chemical substance specially used
to improve the fluidity and leveling of coatings. It is usually composed of specific organic
compounds, which can significantly reduce the surface tension of the coating, so that the coating
forms a flat, smooth and uniform coating film during the drying and film-forming process.
2. The working principle of PU leveling agent
The working principle of PU leveling agent is mainly based on its ability to reduce the surface
tension of the coating. When the coating is applied to the substrate, the PU leveling agent can quickly
migrate to the surface of the coating to form a monomolecular layer. This monomolecular
layer can significantly reduce the surface tension of the coating, so that the coating can
spread and flow better on the substrate. At the same time, the PU leveling agent can also balance
the tension difference on the surface of the coating and eliminate various defects caused
by uneven surface tension, such as scratches, orange peel, shrinkage holes, etc.
3. Types of PU leveling agents
There are many types of PU leveling agents, which can be divided into the following categories
according to their chemical structures:
Organic silicone PU leveling agents: This type of leveling agent is represented by polydimethylsiloxane
and its modified products, which can significantly reduce the surface tension of the
coating and improve the wettability and fluidity of the coating.
Acrylic PU leveling agents: Acrylic leveling agents usually have excellent compatibility and stability,
which can improve the fluidity and leveling of the coating, while improving the gloss and
wear resistance of the coating.
Fluorocarbon PU leveling agents: This type of leveling agent has extremely low surface energy and
can significantly improve the stain resistance and weather resistance of the coating, but the
cost is relatively high.
4. Application of PU leveling agents in coatings
PU leveling agents are widely used in various coating systems, especially in situations where high
flatness and smoothness are required. The following are several main application scenarios
of PU leveling agents in coatings:
Automotive coatings: In the process of automobile manufacturing, the flatness and smoothness
of the coating are crucial to the appearance quality of the vehicle. PU leveling agent can
significantly improve the fluidity and leveling of automotive coatings, eliminate various defects
on the surface of the coating, and improve the gloss and smoothness of the coating.
Wood coatings: Wood coatings need to have good wettability and permeability so that they
can better penetrate into the tiny pores of wood. PU leveling agent can improve the wettability
and permeability of wood coatings, so that the coatings can better adhere to the wood surface,
while improving the wear resistance and weather resistance of the coating.
Industrial coatings: In the industrial field, coatings need to have good construction performance
and coating quality. PU leveling agent can significantly improve the fluidity and leveling of
industrial coatings, so that the coatings can 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 for using PU leveling agent
When using PU leveling agent, you need to pay attention to the following points:
Dosage control: The amount of PU leveling agent should be adjusted according to the type of
coating and construction conditions. Excessive dosage may cause the viscosity of the coating to
drop too much, resulting in defects such as sagging; while too little dosage may not fully exert its
leveling effect.Compatibility test: Before using PU leveling agent, a compatibility test should be carried out to ensure
that it has good compatibility with the coating system. If the compatibility is poor, it may
cause defects such as delamination and cracking in the coating film.
Construction environment: The construction environment also has an important influence on the fluidity
and leveling of the coating. Therefore, when using PU leveling agent, attention should
be paid to controlling the temperature, humidity and wind speed of the construction environment to obtain
the best construction effect.
6. Conclusion
As an important additive in the coating industry, PU leveling agent plays an important role in various coating
systems with its unique properties. By understanding the basic knowledge,
working principle, types and application of PU leveling agent in coatings, this additive can be better used to
improve the construction performance and coating quality of the coating.
