PIGMENT BLUE 28/ Cobalt Aluminate Blue 91480
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Technical Information
What Is PB28 / Cobalt Aluminate Blue 91480
CAS 1345-16-0, CI 77346, Type: Cobalt Aluminate (CoAl2O4). This inorganic pigment features a spinel crystal structure that delivers extreme thermal stability exceeding 1000°C, making it capable of surviving conditions that destroy any organic pigment. PB28 offers a distinctive reddish-blue shade with exceptional lightfastness and chemical resistance, remaining completely inert and non-migrating in all applications. The spinel crystal form ensures permanent color retention under extreme processing conditions.
Why Choose Cobalt Aluminate Blue 91480
This specific grade of PB28 is optimized for plastics applications where extreme thermal and chemical stability are non-negotiable. During high-temperature plastic processing, organic blues like phthalo or ultramarine degrade or shift color, while Cobalt Aluminate Blue 91480 maintains its exact shade and performance. Its lower tinting strength compared to organic blues is offset by unmatched durability — the pigment withstands repeated thermal cycles without fading or migrating. For engineering plastics, architectural coatings, and high-temp ceramics requiring long-term outdoor exposure, this grade outperforms all alternatives. There are no sibling grades for this product; PB28 is a single, specialized solution for demanding environments where standard organic pigments fail.
Key Features
- The spinel crystal structure provides heat resistance above 1000°C, surviving conditions that destroy any organic pigment.
- It offers a unique reddish-blue shade with excellent lightfastness and chemical resistance in all environments.
- The pigment is completely inert and non-migrating, ensuring stable performance in plastic matrices.
- Its low tinting strength is offset by unmatched durability, making it ideal for high-temperature ceramics and engineering plastics.
- It is the only solution for applications requiring extreme thermal and chemical stability, with no sibling grades available.
C.I.NO.: PB28
Advantage:
Main Application Recommended: Plastics
Product Description Description – PB28
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Cobalt Aluminate Blue 91480 (PIGMENT BLUE 28) consists of minute,very thin, more or less hexagonal flakes. A high-temperature calcined blue pigment with excellent chemical resistance, outdoor durability, light fastness, thermal stability, no bleeding and no migration. Widely used in fields with high requirements for heat resistance, weather resistance and light resistance; compatible with most resins or polymers. Reddish hue, small particle size, easy to disperse; strong tinting power, good hiding power, etc.
>Recommended Application
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Coatings: solvent based paints, water based paints, auto paints, industrial coatings, powder coatings, wood coatings, coil coatings
Plastics: PE, PP, PBT, PVC, PET, EVA, ABS
>Technical Data
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| Product Information | ||||
| Chemical Type | Co-Al-O | CAS NO. | 1345-16-0 | |
| C. I. Name | Pigment Blue 28 | EINECS / ELINCS NO. | 310-193-6 | |
| C. I. Constitution No. | 77346 | Chemical Formula | ||
| Technical Performance | ||||
| Full Shade | Tint | |||
| Weather Resistance | 5 | 5 | Heat Stability °C | 800°C |
| Light Fastness | 8 | 8 | ||
| Physical Properties | ||||
| Physical Form | Powder | Resistance to Acid | 5 | |
| Mean Particle size um | ≤2 | Resistance to Alkali | 5 | |
| Moisture Content | 0.002 | |||
| Water soluble salt | 0.0017 | |||
| Oil Absorption g/100g | 34.26 | |||
| PH | 6~9 | |||
| 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?
- 🌍 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 PB28
What is the primary application fit for Cobalt Aluminate Blue 91480 in plastics?
PB28 (Cobalt Aluminate Blue 91480) is specifically engineered for high-temperature plastic processing, including engineering thermoplastics like polycarbonate (PC), polyamide (PA), and ABS. Its exceptional thermal stability (up to 1000°C) makes it ideal for applications requiring prolonged exposure to heat, such as automotive components, exterior building profiles, and outdoor furniture. Unlike organic pigments, it resists migration and warpage in crystalline polymers. For general-purpose thermoplastics like polyethylene or polypropylene, it offers superior weatherability and lightfastness, ensuring color retention even under intense UV exposure. However, it is not recommended for transparent applications due to its opacity.
What are the performance limits or processing risks of this pigment?
The main performance limit is its high specific gravity (approximately 4.3 g/cm³), which can cause settling in liquid colorants or uneven dispersion in injection molding if not properly compounded. It is also sensitive to acidic environments; prolonged contact with strong acids may cause color shift or fading. During processing, over-shear or excessive milling may break down its crystalline structure, reducing color strength. Additionally, PB28 has moderate oil absorption, so masters batch formulations may require surfactant optimization. Avoid using in flexible PVC with high plasticizer levels, as leaching or blooming can occur over time.
How does PB28 compare to its sibling Cobalt Blue (PB36) in plastic applications?
PB28 (Cobalt Aluminate Blue) and PB36 (Cobalt Chromite Blue) are chemically distinct. PB28 offers a cleaner, brighter blue with higher tinting strength and better opacity, making it preferable for vibrant, solid colors. PB36, being a chromite-based spinel, has higher infrared reflectance and is often used for “cool roof” coatings. In plastics, PB28 performs better in transparent systems when opacity is desired, while PB36 is more stable in alkaline environments. For cost-sensitive commodity plastics, PB28 is generally more economical per unit of color strength. Both offer excellent weatherability, but PB28 is less abrasive to molds due to its smoother particle shape.
What are the recommended processing conditions and dispersion techniques?
For optimal dispersion, PB28 should be pre-mixed with a dispersant or ground into a master batch at a 10–20% pigment loading. Twin-screw extrusion with high shear is recommended for uniform distribution. Processing temperatures can range from 180°C to 320°C without color degradation. In injection molding, avoid prolonged residence time above 280°C to prevent slight shifts toward greenish-blue. Use a melt temperature of 240–260°C for polyolefins and 270–300°C for engineering plastics. For liquid color, employ ball milling for at least 1 hour with a low-viscosity carrier to prevent sedimentation.
How should PB28 be stored, and what alternatives exist if supply is limited?
Store PB28 in a cool, dry place away from humidity and acidic vapors. Sealed containers prevent moisture absorption, which can cause agglomeration during compounding. Shelf life is typically 10+ years when stored properly. If substitution is required, consider PB29 (Ultramarine Blue) for low-temperature applications, but note PB29 has poor acid resistance. For high-heat applications, Phthalocyanine Blue (PB15:3) is an alternative if temperatures remain below 200°C, but UV stability will be inferior. For strict long-term outdoor use, only PB36 (Cobalt Chromite Blue) offers comparable weatherability and thermal resistance.
Cobalt Aluminate Blue 91480 takeaway: PB28 is the ideal choice for high-temperature plastics requiring brilliant, opaque blue shades with unmatched heat stability, UV resistance, and cost efficiency. Its superior dispersion and non-migrating properties make it reliable for demanding automotive, architectural, and outdoor plastic applications where color consistency over decades is non-negotiable.
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