Water-based wood coating fully enclosed varnish coloring coating process

When using ordinary varnish to modify the color, the reason why the color control is difficult is that there are some opaque materials that affect the transparency of the varnish or affect the adhesion between layers, such as sanding agents, opaque wax pastes, matting powders and so on.
These materials should be removed as much as possible in the color repair varnish to make the function of the color repair varnish more specific.

2.
3.
3 Influencing factors of constructability control

2.
3.
3.
1 Rheology

The ideal color trimming effect is to obtain a uniformly colored, flat and smooth surface.
In order to achieve this effect as much as possible, there must be no shrinkage, black edges, sagging, orange peel, and particles during the construction process.
In the actual construction process, a small amount of orange peel and particles are unavoidable.
It can be covered and filled by moderate sanding and topcoat, and finally a more ideal coating effect can be obtained.
There are almost no problems with shrinking edges, black edges and sagging.
Therefore, it is necessary to effectively restrict the flow of paint during the color repair varnish construction.
In order to ensure the flatness of the board surface, the coating film after construction must be leveled as much as possible, which requires the color repair varnish to have a certain level of leveling.
Generally, the leveling problem can be solved by choosing a suitable thickener and extending the drying time of the coating film.

2.
3.
3.
2 Construction viscosity

In mass production, color repairing is done by manual production.
The spraying equipment generally chooses the lower pot type ordinary air spray gun, and the spray gun caliber is generally 1.
3mm or 1.
5mm.
The construction viscosity needs to be adjusted appropriately according to the size of the sprayed object.
When the construction object is large, the viscosity should be appropriately low, generally 13-15s (2#); when the construction object is small, the viscosity should be appropriately higher, which can be 16-20s (2# Yantian Cup).
This is because when operating on a large area, the spray gun will be farther away from the surface of the coated object, the paint mist will be exposed to the air for a longer time, and the viscosity of the paint mist will be higher when it reaches the surface of the coated object, which needs to be reduced.
The construction viscosity is suitable to ensure that the viscosity of the paint mist reaches the surface of the object to be coated.
At the same time, the spray gun has a long back-and-forth cycle during large-area operation, and the time that the coating film is exposed to the air will be prolonged.
This also requires reducing the construction viscosity to ensure that the coating film can have time to level when the color repair is completed.

2.
3.
4 Common problems and solutions in construction

2.
3.
4.
1 Interlayer compatibility and adhesion

In color repair, the more transparent the color repair varnish, the better, but the better the transparency of water-based resins, the mechanical properties or cost performance are often not high.
This means that in order to achieve better mechanical properties or cost-effectiveness, some water-based resins with low transparency will be widely used in primers and topcoats.
In the entire construction process, if only the color repair problem is considered, the color repair varnish can use a water-based polyurethane dispersion with better transparency, which not only has good transparency, but also has better wettability.
However, water-based PU (polyurethane) dispersions and water-based AC (acrylic) primers and water-based AC topcoats often suffer from poor compatibility and poor interlayer adhesion.
Therefore, when making color repairing varnish, not only the color repairing construction problem must be considered, but also the compatibility and poor adhesion between the color repairing varnish and the primer and top coat after the color repairing.
In order to reduce the hidden dangers of the product during use, the color repair varnish and the resin used in the primer and topcoat should be as consistent as possible.

2.
3.
4.
2 White point

White spot refers to the phenomenon that the color correction varnish does not color the uneven or not polished place on the primer substrate during color repair.
This phenomenon is caused by the poor wettability of the color repair varnish or the primer itself is difficult to wet.
It is mostly related to the performance of the resin in the primer or the color repair varnish.
It is often difficult to achieve complete improvement by changing the type and amount of wetting agent.
the goal of.
Therefore, it is generally the first choice to replace the primer or color repair varnish resin when this problem occurs.
If it is determined that it is a primer problem rather than a color repair varnish problem, you can also apply a primer on the primer that can be easily wetted and does not have compatibility.
For transitional primers that have problems with sex and adhesion, wait for the primer to dry before trimming, and there will be no white spots.

3.
Conclusion

The coloring and coating of water-based wood coating closed varnish is a hurdle that has to be overcome in the development process of water-based wood coatings.
This article introduces and compares some common coloring methods, and proposes a special color-repairing varnish color-repairing method.
Production practice has proved that this method is more effective, but there are still many areas to be improved in the product development of color repair varnishes, such as there are more microbubbles during the color repair construction, how to ensure that the coating film is dried as much as possible The flatness of the entire plane can reduce the spray thickness of the topcoat.
The author believes that through the joint efforts of people in the industry, these problems will definitely be solved, and only when this problem is completely solved, can water-based wood coatings get rid of the limitations of their original coating >(Source: Global Coatings Network) (For more information, please log in: Global Coatings Network http:// )