What Is an Acrylic Emulsion?
An Acrylic Emulsion is an acrylic resin which is emulsified and dispersed in a solution.
They have excellent gloss, weather resistance, stain resistance, and are often used in coatings for housing construction materials.
Acrylic emulsions are often emulsified and dispersed in water.
In addition, since acrylic resins can be freely designed, various types of emulsions have been developed for applications other than housing construction materials.
Uses of Acrylic Emulsions
Acrylic emulsions are available in two types: organic solvent-based and water-based.
- Solvent-Based Emulsions
Acrylic resin is emulsified and dispersed in an organic solvent such as thinner.
Solvent-based emulsions have the following advantages:
- Acrylic resin and organic solvent blend wells, and emulsions are easier to make than water-based emulsions.
- Excellent water resistance and adhesion, and resistance to rain and wind.
- Good elongation when applied, and easy to use as a coating.
- Because of its water resistance and paintability, it was widely used for the exterior walls of houses.
However, organic solvents also have problems with air pollution and adverse health effects. Sick building syndrome, which has become a problem, is one of the causes of organic solvents.
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Water-based emulsion
Acrylic resin is emulsified and dispersed in water.
Since organic solvents are not used, these emulsions are environmentally friendly and are now the mainstream method used.
As an alternative to solvent-based emulsions, they are widely used in housing construction materials.
Principle of Acrylic Emulsions
Emulsifiers play a major role in emulsions. Resin and water do not mix well together, so they separate when mixed normally.
Emulsifiers consist of hydrophilic groups that are compatible with water and hydrophobic groups that are compatible with resin. When an emulsifier is added, hydrophilic groups are placed on the water side and hydrophobic groups on the resin side, forming spherical aggregates. The stable existence of many micelles results in an emulsion.
Particles are uniformly dispersed among each other because of the influence of electric charge.
Along with the electrostatic repulsive force, an attractive force also acts. Attraction is the force that attracts objects.
If the balance between repulsion and attraction is lost, particles will agglomerate.
What Are Acrylic Emulsion Paints?
Acrylic emulsion paints dissolve easily with water only and become water-resistant when dried.
A unique feature of these paints is that discoloration after drying is reduced. Acrylic emulsions are usually a mixture of pigment, water, and acrylic resin, resulting in a milky white color. Discoloration occurs when the paint dries due to evaporation of water. By using acrylic resins with high transparency, discoloration is reduced after drying.
Acrylic emulsion paints harden as time passes after application.
Types of Acrylic Emulsion Paints
Acrylic emulsion paints are classified into three main types. They are transparent acrylic paints, opaque acrylic gouache, and ink-like liquid acrylic paints.
Acrylic paints are characterized by their high transparency. The intensity of color can be adjusted by using curing to enable layering. In addition, the flexibility of acrylic resin allows painting on hard objects such as cement and metal, as well as softer objects such as clothing. It is also attractive that there are a full range of auxiliary paints that further aid expression are also available.
Acrylic gouache paints are acrylic paints with less acrylic resin and more pigment. They are characterized by colors that cover the color of the underlying layer and have a matte effect. It is resistant to uneven brush strokes even after it dries. It is also compatible with oil-based paints which can be painted over acrylic gouache paints.
The disadvantage is the lack of flexibility due to the low acrylic resin content. It cannot be painted thickly in one coat, and requires layering. It is also not suitable for outdoor painting due to its weak adhesion.
Acrylic liquid paints are designed for airbrush emulsion spraying. If more water is distributed, it does not mix well with the acrylic resin. As a result, the color will separate over time. Due to the low pigment distribution, these paints are sensitive to light and are intended for indoor use.
Types of acrylic emulsion paints are classified according to the water and acrylic resin to be mixed.