Solvent Blue 45 / Solvent Dyes
s for bottle coloration: (1) exceptional thermal s
Technical Information
Color Index: Solvent Blue 45
Molecular formula: C44H52N4O6S2
CAS No.: 37299-23-5
Solvent Blue 45 is a blue solvent dye with good light fastness and very good heat resistance.
Applications: In PET spin dyeing, good values are obtained in textile properties (wash and rubbing fastness and fastness to dry heat setting). Further applications include the coloration of PET bottles.
Description
Solvent Blue 45 is a blue solvent dye with good light fastness and very good heat resistance. In PET spin dyeing, good values are obtained in textile properties including wash fastness, rubbing fastness, and fastness to dry heat setting. Further applications include the coloration of PET bottles.
Product Overview — Why Solvent Blue 45?
Solvent Blue 45 is a premium anthraquinone solvent dye specifically optimized for polyethylene terephthalate (PET) applications, delivering exceptional wash fastness, rubbing fastness, and dry heat setting resistance in spin-dyed polyester fibers and PET bottle coloration. With a heat resistance ceiling of 330°C in polycarbonate and 310°C in PET, SB45 exceeds the thermal performance envelope of standard solvent dyes, enabling high-speed injection molding and extrusion without perceptible color shift. Its light fastness rating of 7-8 (Blue Wool Scale) in transparent PET at 1/25 standard depth ensures years of color stability in outdoor packaging, beverage bottles, and industrial textiles. The unique molecular structure — C₄₄H₅₂N₄O₆S₂, incorporating dual sulfonamide functional groups — enhances solubility in the PET melt phase while maintaining migration fastness that meets food-contact packaging requirements. Compared to Solvent Blue 97, SB45 is the specialist choice for PET bottle preform molding at 280-300°C, where its higher molecular weight provides reduced volatility during melt processing and superior shade consistency across production batches. Key applications include carbonated beverage bottles, cosmetic and personal care packaging, and high-tenacity polyester industrial yarns where color performance directly impacts product value and brand perception in competitive retail environments.
Identification Information
Color Index: Solvent Blue 45
Molecular formula: C44H52N4O6S2
CAS No.: 37299-23-5
Product Specification
Appearance: Blue powder
The fine blue powder morphology ensures rapid dispersion and uniform color uptake during PET melt-phase dyeing, eliminating visible color streaks in bottle preforms and fibers.
Tinting Strength: 100±3%
A tinting strength of 100±3% indicates standard full-strength performance, with the tight ±3% tolerance ensuring that PET bottle shade remains consistent across multi-cavity molds and extended production runs.
Shade: Color Similar to the standard
Shade conformance to a certified reference standard guarantees visual color consistency — essential for brand owners whose packaging color specifications form part of their trademark identity.
Ash: ≤ 1.0%
Low ash content below 1.0% minimizes insoluble particulates that could cause filtration pressure buildup during PET melt spinning or create visible specks in high-clarity bottle applications.
Moisture: ≤ 1.0%
Controlled moisture below 1.0% prevents hydrolytic degradation of the dye during PET processing at 280-300°C, maintaining full color strength and avoiding bubble defects in transparent packaging.
Color Differential Value ΔE: ≤ 0.8
A ΔE ≤ 0.8 ensures batch-to-batch color variation remains below the human eye’s discrimination threshold (ΔE ~1.0), critical for brand owners performing incoming QC on pre-colored PET resin or masterbatch.
Bulk Density: 1.10 g/cm³
A bulk density of 1.10 g/cm³ reflects the powder’s packing behavior in hoppers and feeders — this relatively low bulk density is typical of high-molecular-weight anthraquinone dyes and requires gentle agitation in gravimetric dosing systems for consistent metering accuracy.
Melting Point: ~ (approximate)
The approximate melting point with gradual softening behavior is characteristic of this high-molecular-weight dye (797 g/mol) — rather than a sharp melt transition, SB45 softens progressively, which enhances its dispersibility in the PET melt phase and reduces the risk of undissolved dye aggregates.
Physical properties
| Items | PS | ABS | PC | PETP |
| Light fastness SD 1/3 Opaque | 6-7 | 5-6 | 6 | 6 |
| Light fastness SD 1/25 Transparent | 7-8 | 5-6 | 7 | 7 |
| Heat resistance SD 1/3 Opaque (℃ | 300 | 300 | 330 | 310 |
Application Profile
| PS | ● | HIPS | ● | ABS | ● |
| PC | ● | PVC-R | ● | PMMA | ● |
| SAN | ● | AS | ● | PA | – |
| PET | ● |
Note: ● = recommended ○ = potential use – = not recommended
Recommended Dosage
Transparent: 0.03
Non-transparent: 0.05
Packaging
Regular Packaging is in 25kgs paper drum, carton or bag. Products with low density will be packed into 10-20 kgs.
Exceptional Color Performance
Solvent Blue 45 is the ultimate solution for achieving vibrant and durable blue hues in a variety of applications. Renowned for its excellent light fastness and outstanding heat resistance, this dye is engineered to deliver reliable, high-performance results every time. Whether you are working with textiles or other PET-based materials, Solvent Blue 45 ensures consistent and visually stunning outcomes.
Optimized for PET Spin Dyeing
One of the key applications of Solvent Blue 45 is in PET (polyethylene terephthalate) spin dyeing. When used in this process, it provides unparalleled benefits, including remarkable wash fastness, exceptional rubbing fastness, and superior resistance to dry heat setting. These properties make it a go-to choice for industries prioritizing longevity and durability in their dyed products.
Perfect for PET Bottle Coloration
Solvent Blue 45 is not just limited to textiles; it also excels in the coloration of PET bottles. Its high thermal stability and consistent color performance make it an ideal choice for creating visually appealing and long-lasting packaging solutions. Whether producing bottles for beverages, cosmetics, or other consumer products, this dye ensures vibrant results that stand out on shelves.
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
📩 Need more details?
Request TDS, SDS, or a free sample for testing.
Technical FAQ — Solvent Blue 45
What makes Solvent Blue 45 the preferred choice for PET bottle coloration versus other blue solvent dyes?
Solvent Blue 45 is specifically engineered for PET applications, offering three decisive advantages for bottle coloration: (1) exceptional thermal stability up to 310°C in PET, matching the processing window of PET bottle preform injection molding (270-300°C) without dye decomposition or color shift; (2) superior wash and rubbing fastness in the final bottle product, as the dye is molecularly dissolved and locked within the PET matrix during solid-state polymerization; and (3) a light fastness of 7-8 in transparent PET at 1/25 SD, ensuring that colored bottles retain their brand-specific shade even after months of retail display under fluorescent lighting. Its high molecular weight (797 g/mol) also minimizes volatilization during the melt phase, an issue that affects lower-molecular-weight solvent dyes used in PET processing.
How does Solvent Blue 45 perform in PET spin dyeing compared to conventional disperse dyes?
In PET spin dyeing (also called dope dyeing or solution dyeing), Solvent Blue 45 outperforms conventional disperse dyes in three critical areas: wash fastness, rubbing fastness, and dry heat setting fastness. Unlike disperse dyes — which are applied to the fiber surface in a post-spinning dye bath and rely on diffusion into the fiber — SB45 is incorporated directly into the PET melt before extrusion. This means the dye is distributed throughout the entire fiber cross-section rather than concentrated at the surface, resulting in color that cannot be removed by washing, abrasion, or subsequent heat setting at 180-200°C. The textile properties achieved with SB45 in PET are equivalent to those of high-performance pigments but without the filter pressure and spinneret abrasion issues associated with particulate colorants in fine-denier fiber production.
What explains Solvent Blue 45’s exceptional heat resistance of up to 330°C in polycarbonate?
SB45’s outstanding thermal stability — rated at 330°C in PC and 310°C in PET — derives from its robust anthraquinone chromophore structure combined with dual sulfonamide substituents (C₄₄H₅₂N₄O₆S₂). The sulfonamide groups (-SO₂-NH-) act as electron-withdrawing stabilizers that increase the activation energy required for thermal decomposition of the conjugated chromophore system. Additionally, the dye’s high molecular weight (797 g/mol) provides a higher boiling point and lower vapor pressure compared to lighter anthraquinone dyes, reducing evaporative loss during high-temperature melt processing. This molecular architecture allows SB45 to survive the 280-300°C preform injection molding cycle for PET bottles — and even the 320-330°C processing range for optical-grade polycarbonate — without measurable color degradation.
Can Solvent Blue 45 be used in food-contact PET packaging applications?
Solvent Blue 45’s migration resistance rating of 5/5 across all tested polymers, combined with its high molecular weight (797 g/mol), provides strong technical evidence for suitability in food-contact PET applications. The dye’s large molecular size effectively prevents migration through the PET polymer matrix — a phenomenon governed by diffusion kinetics where molecules above approximately 500 g/mol show dramatically reduced migration rates in glassy polymers like PET. However, compliance with specific food-contact regulations (FDA 21 CFR, EU 10/2011, China GB 9685) requires verification of the exact grade and any co-additives. Honor Pigments recommends customers request the specific compliance documentation for their target market and end-use conditions. A migration testing protocol following EU 10/2011 with food simulants appropriate to your packaging application is available through our technical service team.