Heat-Resistant Inorganic Pigments | 2013-04-01

Google reveals that heat-resistant inorganic pigments provide durable, vibrant color for various high-temperature applications such as ceramics, plastics, and coatings, ensuring stability and long-lasting performance. This quality makes them indispensable in fields requiring both esthetic and functional durability.

Standard yellow iron oxides, known for their high hiding power and opacity, excellent weather, light, and chemical fastness, are cost-effective pigments for a wide range of color shades. However, their application in high-temperature-cured coatings like coil, powder, or stoving paints is restricted.

Link to CHENGYU

When yellow iron oxides are exposed to high temperatures, their goethite structure (FeOOH) dehydrates and partially transforms into hematite (Fe2O3), resulting in a darker, more brown hue (Figure 1). This transformation can occur at temperatures as low as 160°C, influenced by curing time, binder system, and coating formulation.

Heat-Resistant Inorganic Pigments

Overcoming Poor Heat Fastness

The poor heat fastness of standard yellow iron oxides can be mitigated by incorporating Nubifer K Series zinc ferrites and Nubifer Y-7050 heat-resistant yellow iron oxide pigments.

Zinc Ferrites, Nubifer K Series

Zinc ferrites are complex inorganic pigments with a ZnFe2O4 spinel crystal structure (Figure 2). They offer excellent light, weather, and chemical fastness, high hiding power, and opacity, in addition to high-temperature resistance. However, their tan color differs significantly from yellow iron oxides (Figure 3).

Notable zinc ferrites include Nubifer Y-905K and Nubifer Y-805K. Nubifer Y-805K, darker and redder, is the most heat-stable zinc ferrite available, enduring 300°C for 5 minutes in polypropylene, compared to Nubifer Y-905K's 260°C. Typical curing parameters for coil, powder, and stoving coatings still render Nubifer Y-905K suitable (Figure 4).

Nubifer Y-7050

Our R&D has developed an inorganic encapsulation for yellow iron oxide that prevents color change at high temperatures. This encapsulation is fully inorganic and compatible with various binders.

For instance, in an epoxy acrylic stoving coating, standard yellow iron oxide shows color change at 220°C/20 min, while Nubifer Y-7050 remains stable. At 240°C, the difference is more pronounced, with standard yellow iron oxide turning completely brown while Nubifer Y-7050 retains its color (Figure 5).

Replacing Pigment Brown 24

Titanate chrome brown 24 (PBr 24), used for beige/light-yellow shades in high-temperature applications, can be cost-effectively replaced with Nubifer Y-7050, offering similar performance at a lower cost (Figure 6). Heat stability, Kesternich (SO2 fastness), and QUV-A tests confirm comparable performance in a polyester HAA powder coating (Figure 7).

Replacing Red Organic Pigments

Red organic pigments in coatings can be partially substituted with Nubifer Y-7050 and Nubifer Y-905K without significant color or hiding power changes. This also reduces coloration cost by approximately 25% for PR 254 and 19-20% for PR 170 (Figures 8 and 9). Nubifer Y-905K is particularly effective in minimal color change.

Formulating High-Performance Coatings with Nubifer Y-7050

To develop heat-stable colors in high-temperature-cured coatings, Nubifer Y-7050 provides a lower-cost alternative to high-performance inorganic or organic pigments. Testing confirms its weather fastness and stability in various formulations (Figures 10-12 and Figures 13-15).

Summary

Standard yellow iron oxides are ideal for varied color shades due to their performance and cost advantages. However, their application is limited in high-temperature coatings due to color changes. Nubifer Y-7050 and Nubifer K Series zinc ferrites offer cost-efficient, high-performance solutions for such applications.

• Nubifer Y-7050: Heat-resistant yellow iron oxide with inorganic encapsulation, stable up to 240°C.
• Nubifer K Series: Zinc ferrites, notably Nubifer Y-905K, with minimal color change in high-temperature conditions.

Integrating these products into formulations allows for cost-effective, high-performance coil, powder, and stoving coatings in a range of colors.

Go Green Color Asphalt Pigment is a unique Color Pigment system specifically developed for the Color Asphalt market. Recognized as non-toxic and environmentally friendly, these pigments are easy to disperse, heat resistant, and possess high tinting power, good adherence, excellent light fastness, weather resistance, and chemical resistance.

The product incorporates premium quality inorganic pigments within a unique carrier system, offering consistent coloration of asphalt along with numerous benefits during production, laying, and service.

Advantages

Technical Data Sheet

The company offers the world’s best iron oxide pigments for asphalt. We are your one-stop shop for all needs, with specialized staff ready to help you find the product you need.

ItemIron Oxide RedHeat Stable YellowCompound Ferric GreenCompound Ferric BlueType1301UPT155605103Fe2O3 Content (%) ≥92 ≥82 —— ——

Oil Absorption

(g/100g)

Res. on 325 Mesh

(%)

Water Sol. Salts

(%)

(%)

Tamped Apparent

Density g/cm3

E

Compared with std.

Tingting Strength

(%)

Different colors are available:

Improved Color Consistency Go Green Color Asphalt Pigment is manufactured using a high shear dispersion process, resulting in high levels of color strength and consistency.

Package

25kg kraft bag, 25kg melting PE bag, 1 ton bag

For more information, please visit Iron Oxide Pigment Supplier.