What Is Acrylic Resin-Based NAD Paint?
Acrylic resin-based NAD paint is a paint in which acrylic resin, a component of the paint, is dispersed in an organic solvent in the form of fine particles.
The acronym “Non Aqueous Dispersion” are called NAD paints. Other names for this type of paint include “non-aqueous dispersion paint” and “non-aqueous emulsion paint.”
Uses of Acrylic Resin-based NAD Paints
The solvent normally used for acrylic resin-based NAD paints is a weak solvent type of paint using mineral spirit (paint thinner). Compared to strong solvents such as toluene, xylene, ketone, and ester solvents, weak solvent paints have a milder odor and are less likely to damage the substrate and old paint film, making them widely used for repainting exterior walls and roofs.
Acrylic resin-based NAD paints are used on exterior walls and roofs, concrete, mortar, wood, metal, and other building materials. They have high weather resistance and durability, and provide excellent waterproofing performance against the external environment.
Principle of Acrylic Resin-Based NAD Paints
In acrylic resin-based NAD paint, the solvent evaporates during the drying process after painting, causing the dispersed particles to combine and form a coating film that fixes the paint. Therefore, compared to synthetic resin emulsion paints (EP), which use water as a solvent, acrylic resin-based non-aqueous dispersion paints are characterized by their higher adhesion to the painted substrate and higher water resistance to condensation water.
Another advantage of EP is that it has good coloring, is less susceptible to the effects of old paint films when used for repainting, and has good resistance to burns and stains when used for painting wood. In terms of workability, the hardening property, especially the initial hardening, is good, and the quick-drying property makes it possible to apply two coats in a day and easy to use even in cold regions where the drying time is long.
The reason for its effectiveness and quick-drying properties is that it is a fine particle dispersion type coating. Its thixotropy, in which viscosity decreases during application and increases during standing, makes it easy to apply and prevents sagging. It can also be said to have a milder odor than solvent-based paints that use strong solvents.
However, disadvantages include a stronger odor compared to water-based paints and inferior gloss and strength of the paint film compared to strong solvent-based paints.
Structure of Acrylic Resin-Based NAD Paint
Acrylic resin-based NAD paint is a paint in which resin particles of 0.1 μm to several μm in size are dispersed in an aliphatic hydrocarbon solvent. The paint must be free of formaldehyde preservatives, urea resins, phenolic resins, and melamine resins.
In addition to acrylic resin-based NAD paint, which contains acrylic resin particles and mineral spirits as a dispersant, it also contains pigments, which are coloring components, and dispersants that disperse the resin particles and pigments. Mineral spirit is a mixture of petroleum hydrocarbon compounds with a boiling point of about 160~200℃ and moderate drying properties. It is also used as a paint diluent.
Other Information on Acrylic Resin-Based Nad Paint
Acrylic Resin Particle Dispersion Manufacturing Method
In acrylic resin-based NAD paint, a paint base is created in which acrylic resin particles are dispersed. Pigments and other coloring components are then added to produce products in a variety of colors. Base paints in which acrylic resin particles are dispersed are made by the following procedures.
1. Raw Material Preparation
Dissolve the dispersant in mineral spirits as a dispersant. The dispersant is mainly a high-molecular-weight dispersant rather than a low molecular weight dispersant.
2. Polymerization
To the dispersant in which the dispersant is dissolved, acrylic monomers, which are the raw materials for acrylic resins, and initiators are added in batches or drop-wise to initiate polymerization. At this time, the temperature is heated as necessary. The acrylic monomer and initiator are dissolved in the dispersant, but as the polymerization progresses and the molecular weight increases, they become insoluble in the dispersant and precipitate as particles in the dispersant.
As the particles precipitate, the dispersant adsorbs to the particle surfaces to protect them from aggregating and merging into coarse particles and to stabilize them so that they do not settle.
3. Ripening
To ensure that no un-reacted monomers remain, initiators are added as necessary, and the process is heated.