Different ways to achieve better wettability of water-based coatings!

Coating is a mixed system of multiple components, and its surface or interface has a great influence on the performance of the coating
.
Surface defects often occur during the coating application or drying process.
The defects can lead to poor visual effects of the coating and reduce the ability of the coating to protect the substrate
.

Common defect performance

Poor substrate wettability

Poor flow (orange peel) and shrinkage

reason

1.
A very important parameter is the surface tension of the material involved in the film formation process;

2.
More importantly, the difference in surface tension is the actual cause of these surface defects;

3.
The reasons for the different surface tension include the system itself (evaporation of solvent or crosslinking reaction of resin) or external factors (overspray, dust particles or substrate contamination).
Coating online coatingol.
com
.

Modern water-based coatings are facing a series of technical and commercial challenges.

The wetting phenomenon is a key point, especially in water-based coatings.
Because the surface tension of water-based coatings is very high, it is very important to choose a suitable wetting aid.
Additives that migrate at the interface and adjust surface or interfacial tension can improve wettability
.

Different ways to achieve better wettability

A classic way to increase the wettability of the substrate is to use an additive that can reduce the surface tension of the coating to be coated.

Preferred method

For many years, paint formulators have used this tool to increase the wettability of the substrate, while also improving the wettability of primers, topcoats and intermediate paints.

Three major shortcomings

1.

2.
Different coatings and the wetting process with a given substrate need to be considered.
In a multi-coating system, if the bottom layer has relatively low surface energy, the use of additives to adjust the surface tension will cause problems;

3.
Many wetting agents will cause a series of foam stabilization problems during use, especially the use of fluorine-containing surfactants
.

Classic method

In most coating formulations, organically modified polysiloxanes are used to reduce surface tension (classic silicone additives).

New and unique approach

A new and unique method for multi-coat systems is not to use substrate wetting additives, but to increase the surface energy of the bottom layer (or primer) so that subsequent coatings do not require traditional wetting agents

Different from other surface additives-the new additives can greatly increase the surface energy of the cured coating film.
The result is that there will be perfect wettability in the subsequent coating and a good layer will be produced when recoating.
Between adhesion
.

Summarize

Leveling agents are the basic components of many coating systems.

Using this method, a special acrylic comb copolymer was designed as a surface modification assistant to change the surface energy of the coating, for example, to make the surface hydrophilic or hydrophobic;

Silicone-modified acrylate has a very flexible molecular design, so the coating properties such as hydrophobicity, oil resistance, anti-cratering and slippage can be adjusted very accurately;

The properties that can be directionally adjusted with polyester-modified acrylate are hydrophilic, antistatic, anti-fogging, and improve recoatability and adhesion