PIGMENT RED 101/ IRON OXIDE RED 130
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Technical Information
What Is PY42 / IRON OXIDE RED 130
CAS 51274-00-1, CI 77492, and classified as Iron Oxide (FeOOH), PY42 is a synthetic yellow iron oxide pigment with a goethite crystal structure. It is commonly known as Iron Oxide Red 130 despite its yellow hue, named for its tendency to dehydrate into red Fe2O3 at temperatures above roughly 180°C. This yellow oxide offers strong lightfastness and weather resistance, making it superior to organic yellows for long-term outdoor use. Its lower tinting strength is offset by exceptional durability and high purity relative to natural ochres.
Why Choose IRON OXIDE RED 130
This specific grade is optimized for applications in coatings and plastics, where its thermal sensitivity demands careful processing control to avoid unintended dehydration. Unlike organic yellows that fade rapidly under UV exposure, Iron Oxide Red 130 provides decades of color stability in exterior paints, concrete stains, and plastic siding. Its high purity ensures consistent dispersion and batch-to-batch reliability, outperforming natural ochres that often contain silica or clay impurities. For plastics, the 180°C threshold requires compounding temperatures kept below this point to preserve the yellow goethite structure. When compared to its sibling grades (none exist for this product), this grade stands alone as the balanced choice—offering cost-effective permanence without sacrificing processability in low-to-moderate heat environments. It is the go-to when UV resistance outweighs the need for intense chromatic strength.
Key Features
- Goethite crystal structure provides superior lightfastness and weather resistance compared to organic yellow pigments.
- Dehydration threshold at ~180°C makes it critical to monitor processing temperatures in plastic compounding applications.
- Synthetic manufacturing ensures high purity, eliminating impurities commonly found in natural ochre pigments.
- Lower tinting strength is offset by far greater outdoor durability, reducing the need for frequent color reapplication.
- Versatile for both coatings and plastics, offering consistent performance in construction and industrial formulations.
C.I.NO.: PY42
Advantage:
Main Application Recommended: Coatings, Plastics
Product Description – PR101
IRON OXIDE RED 130 (PIGMENT RED 101) delivers excellent light and weather fastness, ensuring long-term color stability in outdoor or exposed applications. It also has good chemical resistance and cost-effectiveness, making it a reliable choice for coatings, construction materials, and plastics.
Recommended Application：
wall bricks, cements, paving bricks, paintings, coatings, plastics, rubber and so on
Technical Data:
| Product Information | ||||
| Chemical Type | CAS NO. | 1309-37-1 | ||
| C. I. Name | Pigment Red 101 | EINECS / ELINCS NO. | 215-168-2 | |
| C. I. Constitution No. | 77491 | Chemical Formula | ||
| Technical Performance | ||||
| Full Shade | Tint | |||
| Weather Resistance | 5 | 5 | ||
| Light Fastness | 8 | 8 | ||
| Physical Properties | ||||
| Physical Form | Powder | Moisture： | ≤1.0% | |
| Content（Fe2O3 •αH2O）： | ≥96.0% | PH Value: | 3-7 | |
| Oil Absorption: | 15-25 ml/100g | Density： | 0.7-1.0g/cm3 | |
| Residue on Sieve(90 sieve)： | ≤0.3% | particle shape： | Spherical | |
| Water soluble content： | ≤0.3% | Color strength: | 95%~105% | |
| Chromatic aberration △E: | ≤1.0 | |||
| Packaging | ||||
| 25kgs/bag 1000kgs/Pallet | ||||
| Storage | Shelf Life | 5 years | ||
| Should be stored in cool, dry and ventilate place. | ||||
| TRANSPORTATION | ||||
| Avoid inversion, sunlight, moisture and crash. Avoid damage the package. | ||||
- Light fastness: Light fastness rating is assessed on 1 to 8 Blue Wool scale where 1 = ‘Poor’ and 8 = ‘Excellent’.
- Heat Stability : Heat stability values given indicate the maximum temperature at which the pigment can be stoved for 10 min. on the full shade and in reductions without undergoing any significant change in shade.
- Oil absorption: The oil absorption is determined on the basis of EN ISO 787-5 and given in g linseed oil per 100 gm. pigment.
- Solvent bleeding: The bleeding in solvents is tested using the powder grades and the visual rating given on 1 to 5 Grey scale
where 1 = ‘Heavy bleeding’ and 5 = ‘No bleeding”
Technical Note — The data and recommendations provided are based on HONOR Pigment’s internal testing and manufacturing experience. They are offered in good faith to assist customers in evaluating product suitability for their specific applications. As processing conditions, formulations, and end-use requirements vary widely, customers should conduct their own validation under actual use conditions. HONOR Pigment makes no warranties, express or implied, regarding the accuracy of this information or its fitness for any particular purpose. Nothing herein shall be construed as a license or recommendation to infringe any patent. HONOR Pigment’s standard terms and conditions of sale apply.oduct contains particles < 0.1 μm. Any user of this product is responsible for determining the suitability of Honor Pigments’s products for its particular application & to ensure that any proprietary rights & existing laws & legislation are observed.
Why Choose Honor Pigments?
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Frequently Asked Questions About PY42 / Iron Oxide Red 130
What makes PY42 suitable for coatings and plastics applications?
PY42, also known as Iron Oxide Red 130 (CAS 51274-00-1, CI 77492), is a synthetic inorganic pigment that offers excellent thermal stability up to 300°C, making it ideal for high-temperature coating and plastic processing. Its high tinting strength and consistent dispersion ensure uniform color in powder coatings, industrial paints, and masterbatches. The pigment is inherently lightfast and chemically inert, resisting fading from UV exposure and chemical attack in harsh environments. This reliability allows manufacturers to achieve stable, repeatable shades across batches without worrying about degradation during extrusion or baking cycles. For coatings, it provides opaque, matte reds; for plastics, it withstands shear forces and acts as a reinforcing filler in polyolefins and engineering resins.
What are the performance limits of Iron Oxide Red 130?
While robust, PY42 has notable limitations. Its maximum processing temperature should not exceed 300°C for prolonged periods, as decomposition may release iron ions, altering color or causing catalytic degradation in polymers like polyesters. The pigment exhibits poor dispersibility in very high-viscosity systems without optimized wetting agents, leading to agglomerates. Additionally, it lacks the brightness of organic reds (e.g., DPP reds) and cannot produce vivid, transparent shades—only earthy, opaque reds. In thin-film coatings, its particle size (0.1–0.5 µm) may reduce gloss. For plastics, high loadings (>15%) can reduce tensile strength. Always test in your specific resin system.
How does PY42 differ from other iron oxide reds like PR101?
PY42 (Iron Oxide Red 130) is chemically distinct from PR101 (synthetic hematite). PY42 is a synthetic yellow iron oxide (FeOOH) color index, but industrial naming sometimes causes confusion: CI 77492 normally denotes yellow oxides, while CI 77491 denotes red. However, PY42 as traded often refers to a red-shade grade from heat-treated yellow oxides. Compared to PR101, PY42 has a lighter, more orange-red undertone and higher oil absorption (~30–40 g/100g), which can affect paint viscosity. PR101 is more saturated, darker, and has better hiding power. For plastics, PY42 disperses more easily due to its acicular particle shape, while PR101 may produce stronger coloration. Choose PY42 when a warm, clean red with moderate opacity is desired.
What processing precautions are needed when using PY42 in plastics?
When compounding PY42 into thermoplastics, pre-dry the pigment (if hygroscopic) at 80°C for 2 hours to avoid moisture-induced streaks. Use a twin-screw extruder with high shear zones to break soft agglomerates; adding 1–2% of a compatible dispersant (e.g., stearic acid or PE wax) improves uniformity. Avoid exceededing 280°C in polycarbonate or nylon, as iron can accelerate polymer degradation. For masterbatch production, use a carrier with melt flow index (MFI) close to the target plastic to ensure even dispersion. In liquid coatings, grind PY42 in a ball mill for 45 minutes with a dispersant to reach Hegman 6+ fineness. Always verify color shift after processing, as heat can deepen the shade.
How should PY42 be stored, and are there viable substitutes?
Store PY42 in a cool, dry area (<40°C, <60% humidity) in sealed containers away from acids and strong oxidizers, as moisture can cause caking. Shelf life exceeds 5 years if uncontaminated. For substitution, consider PR101 if a darker red is acceptable, or synthetic iron oxide yellow (PY42 in true yellow form) blended with carbon black to create similar earthy reds. For high-brightness applications, replace with an organic pigment like DPP Red BO (Pigment Red 254) but expect a 3–5× cost increase and lower thermal stability. For regulatory compliance (e.g., FDA indirect contact), PY42 is generally approved, but always verify local standards. No direct 1:1 replacement exists for its unique cost-stability balance.
**Iron Oxide Red 130 (PY42) is a cost-effective, heat-stable, and lightfast workhorse pigment for coatings and plastics, delivering reliable earthy reds with moderately good opacity and excellent chemical resistance, though it cannot match organic reds in brightness or transparency and requires careful dispersion for optimal performance.**
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