How Do I Choose the Right Matting Agent?
Choosing a matting agent starts with three variables: target gloss (measured in GU at 60°), resin system, and application method. For gloss below 10 GU at 60°, you need a treated precipitated silica with d50 of 4–6 µm and loading at 5–8% on total formula weight. For semi-matte finishes (20–40 GU), a coarser gel-type silica at 2–4% is more cost-effective. Particle size distribution matters more than average size — a narrow PSD gives consistent sheen with fewer surface defects. Our selection guide maps every GMATT grade to specific gloss targets and resin families.
Which Resin Systems Work With Silica Matting Agents?
Silica-based matting agents are compatible with virtually all resin systems — epoxy, polyurethane, acrylic, alkyd, polyester, and UV-curable chemistries. The key variable is surface treatment. Untreated (hydrophilic) grades like GMATT 100 Series suit waterborne acrylics and epoxies. Wax-treated grades like GMATT 200 Series prevent hard settling in solventborne PU and alkyd systems. For UV coatings curing at 50–120°C, GMATT UV Series uses a reactive surface treatment that avoids oxygen inhibition at the film surface. See our resin compatibility matrix for grade-by-grade recommendations.
How Much Matting Agent Do I Need to Add?
Loading depends on target gloss and film thickness. As a baseline: 3–4% delivers semi-matte (25–35 GU at 60°), 5–6% reaches matte (10–20 GU), and 7–8% achieves deep matte (<10 GU). These figures assume 40–60 µm DFT in a clear system — pigmented formulations need 10–20% higher loading because pigment particles compete for surface roughness. Overloading beyond 10% risks viscosity spikes, poor film integrity, and increased haze. Always run a loading ladder in 1% increments and measure at both 60° and 85° to catch sheen. Our technical guide covers dispersion and letdown protocols.
Why Is My Matting Agent Not Reducing Gloss Enough?
Insufficient matting almost always traces to one of three causes: over-dispersion, wrong particle size, or poor incorporation. High-shear dispersion (above 10 m/s tip speed for more than 5 minutes) breaks silica aggregates below their effective d50, destroying matting efficiency. Under-dispersion leaves agglomerates that cause surface defects without reducing gloss. The fix: disperse at 5–8 m/s tip speed, add the matting agent during letdown (not grind), and verify d50 with a Hegman gauge reading of 3–4. If gloss is still too high after correcting dispersion, step down one particle size grade — moving from 8 µm to 5 µm d50 typically drops gloss 8–12 GU at the same loading.
GMATT Series Quick-Reference Specs
Use this table to narrow candidates before requesting samples. All values are typical for 5% loading in a clear solventborne PU at 50 µm DFT.
| Grade | Type | d50 (µm) | Surface Treatment | 60° Gloss (GU) | Best For |
|---|---|---|---|---|---|
| GMATT 100 | Gel silica | 8–10 | None | 20–30 | Waterborne, low-cost matte |
| GMATT 200 | Gel silica | 5–7 | Wax-treated | 12–20 | Solventborne PU, alkyd |
| GMATT 300 | Precipitated | 4–6 | Organic-treated | 5–12 | High-performance matte, wood |
| GMATT 600 | Precipitated | 3–5 | Untreated | 8–15 | Architectural, industrial primers |
| GMATT WB | Gel silica | 6–8 | Hydrophilic | 15–25 | Waterborne acrylic, latex |
| GMATT UV | Precipitated | 4–6 | Reactive silane | 8–15 | UV-cure, electron beam |
Frequently Asked Questions
Common questions about resources.
+What is a matting agent and how does it work?
A matting agent is a finely divided solid — typically silica — that creates micro-roughness on a cured film surface, scattering reflected light to reduce gloss. Particle size (d50) controls the texture scale: finer particles (3–5 µm) produce smoother matte finishes, while coarser grades (8–12 µm) give more aggressive texture at lower loading.
+Can I use the same matting agent in waterborne and solventborne coatings?
Not ideally. Waterborne systems need hydrophilic (untreated) silica that wets out in water without floating or flocculating. Solventborne systems perform better with wax-treated or organically modified grades that prevent hard packing during storage. Using a waterborne grade in solvent risks settling; using a solvent grade in water risks floating and surface defects.
+What particle size should I choose for my application?
Target gloss dictates particle size. For deep matte (<10 GU at 60°), use 3–6 µm d50. For semi-matte (20–40 GU), use 6–10 µm. For satin (40–60 GU), use 8–12 µm at reduced loading (1–3%). Finer particles give smoother feel but require higher loading, so balance texture, cost, and film properties.
+How do I prevent matting agent from settling in the can?
Settling is a density and rheology problem. Silica (SG ~2.0) is denser than most binders. Use wax-treated grades (like GMATT 200 Series) that form a loose network resisting sedimentation. Add 0.3–0.5% anti-settling rheology modifier. Store at 15–30°C — heat reduces viscosity and accelerates settling. If hard-packed, the batch is typically unrecoverable.
+Does matting agent affect chemical resistance or hardness?
At normal loading (3–8%), silica matting agents have minimal impact on hardness and can slightly improve scratch resistance by reinforcing the film surface. Above 10% loading, film integrity may suffer — reduced flexibility, increased porosity, and lower chemical resistance. Keep loading at the minimum needed for target gloss to preserve coating performance.
+What is the difference between gel silica and precipitated silica matting agents?
Gel silica is produced by acidifying sodium silicate to form a hydrogel, yielding irregular porous particles with broad PSD — lower cost, good for general matte. Precipitated silica is formed by controlled precipitation, giving more uniform particles with narrower PSD — higher matting efficiency per unit loading, preferred for premium low-gloss finishes below 10 GU.
Start with target gloss and resin type — these two variables eliminate 80% of candidates. Then optimize loading and dispersion to fine-tune. Request samples from our GMATT range to validate in your exact formulation.