Water-Based Coatings for Interiors | Exterior - Formulation Design and Application

In today's water-based coatings market, understanding how to use some key components in formulations is important for coating manufacturers. As a supplier of coating raw materials (Resins, Pigments,  Additives, fillers and other paint raw materials. Almost most of coating/paint raw materials, you can find in iSuoChem), iSuoChem helps customers develop high-performance coating products. After around 20 years of working with coating factories and users worldwide, this article shares basic knowledge, formulation design, preparation steps, and trends in water-based architectural coatings.

I. What Are Water-Based Coatings and Their Market Outlook?

With stricter eco-friendly rules and more eco-aware consumers, water-based coatings have become popular in the building industry.  You can find that these coatings have low VOC emissions, are safe to use, and don't have strong smells. Water makes up most of the liquid in these coatings, with only 10-15% being other solvents. This reduces air pollution and safety risks during application.

Water-based coatings can be grouped by their film-forming materials: acrylic esters, vinyl acetate esters, epoxy resins, and polyurethanes. Acrylic esters are widely used. Why? That's because they last long, keep their color and shine, and are cost-effective. As a raw material supplier of water-based coatings, knowing this market helps iSuoChem give better product support.

II. Main Parts and Jobs of Water-Based Coatings

1. Base Resin

The base resin forms the coating's film . It also affects hardness, stickiness, water resistance, and weather durability.

· Acrylic Emulsion: A key base material with good light-resistance, weather-durability, and anti-oxidation. Used for indoor and outdoor walls. For example, BASF's Acronal® PS 713 ap is made for cement uses and sticks well to different surfaces. (iSuoChem offers equivalent quality products at lower prices)

· Styrene acrylic Emulsions: Made from styrene and acrylate, they are low-cost, hard, and water-resistant. Styrene acrylic emulsions are often used in interior paints and primers.

· Epoxy Emulsions: Great stickiness, chemical resistance, and rust protection. Used in floor coatings and anti-rust primers.

· Polyurethane Dispersions: Flexible, scratch-resistant, and clear. Used in wood coatings and topcoats.

2. Pigments

Pigments give color and hiding power. There are white pigments and colored pigments in the coating market.

· Titanium Dioxide (TiO₂): The main white pigment. It gives great coverage and whiteness. Usually 3-6% of the mix.

· Organic Pigments: Organic pigments(pigment red, yellow, orange, violet, blue, green and other colors) are chosen based on light fastness, weather durability, and chemical stability.

· Effect Pigments:

Floating Glitter Powder: This type of glitter creates a shiny metal look, good for decoration.

Color-Changing Pigments: Change color with heat or light (We call it thermochromic pigment and photochromic pigments. You can find all these above pigments by ispigment.com).

3. Fillers

Fillers help control cost and improve coating performance.

· Mica Powder: Makes the film stronger, more heat and rust resistant, and less permeable. In marking paints, it can be 18-25% of the mix.

· Heavy Calcium Carbonate: Common low-cost filler that increases hardness.

· Wollastonite: Improves scratch and rust resistance.

· Kaolin: Boosts hiding power and suspension.

4. Additives

Additives are used in small amounts,  but they greatly improve making and performance.

· Dispersants: Help spread pigments and fillers evenly, prevent settling.

· Thickeners: Adjust thickness, improve application and anti-sag.

· Wetting Agents: Lower surface tension, help spread on surfaces.

· Leveling Agents: Make the film smooth, remove brush marks.

· Defoamers: Stop or remove bubbles during making and use. Usually 0.5-1.1%.

5. Solvents and Water

Water is the main liquid, usually 4-7.5% of the mix. Sometimes a bit of co-solvent is added to help film formation and flow.

III. Example Formulations and Explanations

Here are some common water-based coating recipes showing how much of each part to use.

1. Water-Based Marking Coating

For marks needing good coverage and durability.

How to Make: Mix water, titanium dioxide, heavy calcium carbonate, mica powder, dispersant, and co-solvent well. Grind into a color paste. In another container, mix emulsion and other additives with fast stirring. Add the color paste to the emulsion, mix, and filter.

2. Multi-Use Water-Based Wall Coating

For walls needing waterproofing, fire resistance, heat and sound insulation.

3. Water-Based Acrylic Wood Coating

For indoor wood surfaces, eco-friendly and works well.

· Acrylic Emulsion: 40-60%

· Defoamer: 0.2-0.8%

· Wetting and Dispersing Agent: 0.5-1.5%

· Titanium Dioxide (if needed): 5-15%

· Filler (e.g., mica powder): 5-10%

· Thickener: 0.2-1.0%

· Film-forming Aid: 3-6%

· Water: Add to 100%

IV. Key Steps in Making Water-Based Coatings

The making process affects the final product quality.

1. Pre-dispersion: Add water, dispersant, some defoamer, pigments, and fillers to a mixing tank. Stir fast until smooth.

2. Grinding: Grind the mixed slurry with a sand mill or three-roll mill until fine (usually 20-30 μm).

3. Mixing: Add emulsion base and other additives to the ground slurry. Stir slowly to avoid bubbles.

4. Viscosity Adjustment: Add thickener to get the right thickness.

5. Filtration and Packaging: Remove bits and pieces through a filter, then pack.

During production, control stirring speed, temperature, and pH to keep the system stable and avoid problems.

Water-based coating technology offers great chances for material suppliers and makers. Working closely with coating manufacturers to create special resins, effect pigments, and functional additives for specific uses can help stand out in a busy market.

FAQ

1. How to repair coating settling and separation?

In coatings, solid particles like pigments can separate from the liquid. This happens because of gravity or because the particles have a different density. This leads to an uneven mixture.

Cause: Pigments and fillers are heavy, not thick enough.

Fix: Use better thickeners, add anti-settling agents, increase low-shear viscosity.

2. Too many bubbles in paint?

 Cause: Too much surfactant, too fast stirring.

 Fix: Add the right defoamer, improve stirring method.

3. How to fix the pinchpores in my coatings?

Tiny holes, called pinholes, can appear in a dried coating film. They are often caused by air or solvents that were trapped during application and then burst out as the film cures.

Cause: Uneven surface tension, dirt.

Fix: Add wetting agent, clean equipment well.

4. How to solve the problem of slow paint drying speed?

Cause: High humidity, slow evaporation of film-forming aids.

Fix: Change film-forming aid amount, add some additives, like CAB resins, acrylic resins or others.