IRON OXIDE RED 110/ PIGMENT RED 101
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Technical Information
What Is PY42 / PIGMENT RED 101
PY42 / Pigment Red 101, with CAS number 51274-00-1 and CI 77492, is an Iron Oxide (FeOOH) pigment. Known as iron oxide yellow with a goethite structure, it naturally dehydrates to red Fe2O3 above approximately 180°C, making temperature control critical for plastics applications. It offers good lightfastness and weather resistance, with lower tinting strength than organic yellows but far superior outdoor durability. Synthetic grades provide higher purity than natural ochres, making it ideal for construction, industrial coatings, and plastics.
Why Choose PIGMENT RED 101
This specific grade of Pigment Red 101 is optimized for coatings and plastics applications where thermal stability and longevity are paramount. Its advantage lies in balancing cost-effectiveness with exceptional weatherability, outperforming organic yellows in exterior exposure tests. For coatings, it provides reliable color retention in industrial and architectural finishes. In plastics, its high purity synthetic form ensures consistent dispersion and color strength while maintaining the critical dehydration temperature threshold. Unlike organic alternatives that fade or chalk outdoors, this grade maintains integrity for decades. It is the preferred choice when the application demands resistance to UV, moisture, and chemical exposure. When compared to other iron oxide shades, this yellow variant offers unique opacity and tinting characteristics without sibling grades to complicate selection.
Key Features
- Dehydrates to red Fe2O3 above ~180°C, setting a critical thermal limit for plastics processing.
- Offers excellent lightfastness and weather resistance outlasting organic yellow pigments in exterior use.
- Synthetic production ensures higher purity and consistent particle size compared to natural ochres.
- Provides durable tinting strength specifically suited for industrial coatings and plastic masterbatches.
- Maintains color stability under prolonged UV exposure without significant chalking or fading.
C.I.NO.: PY42
Advantage:
Main Application Recommended: Coatings, Plastics
Features:
IRON OXIDE RED 110 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. | ||||
Why Choose Honor Pigments?
- 🌍 Global Export Expertise — Trusted by customers in 40+ countries for consistent quality and reliable supply
- ✅ Strict Quality Control — ISO 9001 certified with batch-to-batch consistency and zero-defect policy
- 💰 OEM Production Advantage — Competitive pricing without compromising pigment performance
- 🧪 Technical Support — Free color matching, formulation advice and sample testing before bulk order
Frequently Asked Questions About PY42
Is PY42 / Pigment Red 101 suitable for both coatings and plastics applications?
Yes, PY42 (CAS 51274-00-1) is a synthetic iron oxide red widely used across coatings and plastics due to its excellent chemical stability and UV resistance. In coatings, it delivers high opacity and weatherability for architectural, industrial, and automotive primers. In plastics, it withstands processing temperatures up to 250°C and is compatible with thermoplastics like polyolefins, PVC, and ABS. However, for high-gloss finishes or transparent effects, its relatively large particle size may reduce clarity. For most demanding outdoor applications, it outperforms organic reds in color retention. Always pre-test dispersion in your specific resin system to avoid agglomeration.
What are the main performance limits of Pigment Red 101 (CI 77492) in terms of heat and light stability?
Pigment Red 101 offers outstanding heat stability up to 300°C in short-term processing, making it ideal for plastics injection molding and powder coatings. Lightfastness is excellent—typically rated 7-8 on the blue wool scale—ensuring minimal fading even under prolonged UV exposure. The main limitation is its inherent dullness: it produces earthy, opaque reds rather than vibrant, transparent shades. It also has lower tinting strength compared to organic reds, meaning higher loadings are needed for intense colors. Additionally, in acidic or highly alkaline environments (pH 11), slight surface staining may occur. For outdoor coatings, confirm with a QUV test.
How does PY42 compare to its sibling Pigment Yellow 42 or other iron oxide reds?
PY42 is chemically identical to Pigment Yellow 42—both are α-Fe2O3; the color difference arises from particle shape and size distribution. PY42 (red) features larger, more acicular particles, giving better hiding power and redder shade, while Yellow 42 is finer and more yellow. Against other iron oxide reds like Pigment Red 101 (CI 77491, hematite), PY42 is almost synonymous—both provide similar durability and chemical resistance. The key sibling distinction: CI 77492 (PY42) specifically denotes the yellowish-red variant. Compared to organic reds (e.g., PR 254), PY42 is far cheaper and more lightfast but lacks brightness. In blends with organics, it reduces cost while improving weatherability.
What processing precautions are recommended when using Pigment Red 101 in plastics compounding?
For plastics compounding, PY42 (CAS 51274-00-1) requires good dispersion due to its high specific gravity (~5.0) and tendency to agglomerate. Pre-dry the pigment at 80-100°C if stored in humid conditions to avoid moisture-induced defects. Use a twin-screw extruder with high shear zones or a masterbatch approach with 40-60% pigment loading in a carrier resin. Avoid exceeding 280°C processing temperature for prolonged periods, as surface water may cause blistering. Anti-dust grades are recommended for safety. In injection molding, ensure adequate back-pressure to break agglomerates. Thorough dispersion improves color strength and prevents streaking in final parts. Always verify compatibility with antioxidants and flame retardants.
Can PY42 be stored long-term, and what are suitable substitution options if supply issues arise?
PY42 is chemically inert and can be stored for 2+ years in sealed, dry containers away from extreme heat and moisture. Avoid stacking bags too high to prevent caking from pressure. For substitution during supply disruption, consider synthetic iron oxide black (Pigment Black 11) blended with vermilion organics (e.g., PR 170) to approximate the shade, though lightfastness will decrease. Alternatively, calcined iron oxide reds (e.g., Pigment Red 101, CI 77491) are directly interchangeable but shift slightly yellow-red. Trial first—substitution rates typically require 10-15% more pigment to match opacity. Natural red oxides are not recommended due to inconsistent particle size. For critical outdoor uses, always requalify the substitute with UV weathering tests.
Pigment Red 101 takeaway: PY42 is a cost-effective, ultra-durable iron oxide red ideal for high-performance coatings and plastics where weatherability and opacity matter more than vibrant color. Its stability and UV resistance make it a workhorse, but expect muted shades and higher loadings compared to organics. Proper dispersion and temperature control unlock full value, while it serves as a reliable, non-hazardous alternative to heavy-metal pigments in regulated markets.
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