Durable coatings – PA12 powders for high performance, burnish and mar-resistant coatings
New advanced architectural paints, wood coatings, and more generally industrial coatings (for home appliance, for instance) are designed to withstand the intensive use and high-volume traffic of commercial, institutional, and residential buildings. Formulators need to create a wide variety of glossy to matte, smooth to textured finishes with excellent durability, suitable for use in a variety of environments.
Burnish resistance is a key property for matte and semi-gloss coatings. Conventional matting agents have limitations when it comes to formulating burnish-resistant coatings. Orgasol® polyamide 12 powder offers a unique combination of properties, which makes it the additive of choice for the formulator.
Orgasol® PA12 powder key properties for burnish resistance:
- Unique spherical shape and narrow particle size distribution
- Wide range of particle size, from 5 to 60 microns
- Semi-crystalline polyamide 12 : a combination of hardness and flexibility
- Good compatibility with all binders
Furniture Coating Formulation: A deep matte, clear, burnish resistant topcoat
A 2-component polyurethane deep matte coating formulated using Orgasol® polyamide 12 powders.
| Weight Composition % | Formulation | Supplier |
| PART A | ||
| Butyl Acetate | 9.2 | |
| SYNOCURE® 213 BA 50 | 33.4 | ARKEMA |
| OCTA SOLIGEN ZINC 8% | 0.1 | Borchers |
| Butyl Acetate | 16.2 | |
| Solution CAB 381-2 (10% AB-PMA) | 28.7 | Eastman |
| BORCHI® GOL LAC 80 (10% in ethyl acetate | 0.2 | Borchers |
| ORGASOL® 2001 UD NAT1 | 2.5 | ARKEMA |
| ORGASOL® 2002 D NAT1 | 3.0 | ARKEMA |
| PART B | ||
| DESMODUR® N75 BA | 3.2 | Covestro |
| Butyl Acetate | 6.0 |
Orgasol® and Synocure® are registered trademarks of Arkema Inc. Borchi® is a registered trademark of Borchers GmbH. Desmodur® is a registered trademark of Coverstro Deutschland AG
Burnish Resistance Test
In order to evaluate burnish resistance, a coated panel is submitted to rubbing using a felt pad for a defined number of cycles. After rubbing, the gloss of the coating is measured and compared to the initial gloss. The lower the gloss increase, the better the burnishing resistance.
A comparison of Orgasol® PA12 powder performance with a standard matting agent, silica
Burnish Resistance of PA12 Powder vs. Silica
Evolution of Gloss with the Number of Rubbing Cycles
| 0 | 50 | 100 | |
|---|---|---|---|
| Formulation 1 (silica) | 5 | 36 | 46 |
| Formulation 2 (silica and Orgasol® PA12 powder) | 5 | 9 | 10 |
| Formulation 3 (pure Orgasol® PA12 powder | 5 | 5 | 5 |
The superiority of Orgasol® polyamide 12 powder is clear as no change of gloss is observed after the burnishing test was performed. Even a partial substitution of silica with the adapted Orgasol® PA12 powders improves significantly the burnish resistance of the coating, while keeping a very low gloss.
