Solvent Dyes Selection Guide for Transparent Plastics
For purchasing managers and formulation engineers working with transparent engineering plastics, one question comes up more than any other: for the same transparent product, should I use a solvent dye or a pigment? The answer usually comes down to two requirements — transparency and color saturation. As a manufacturer with years of experience in colorants, Aolong's laboratory handles a steady stream of exactly this kind of selection consultation. Today, let's walk through a practical selection guide that makes the logic behind solvent dye selection clear.
I. Why Transparent Products Prefer Solvent Dyes
Solvent dyes are a class of colorants that dissolve in organic solvents. Because they dissolve at the molecular level and disperse uniformly in the resin matrix, they achieve a level of transparency and gloss that pigments cannot match. For transparent engineering plastics such as PC, PMMA and PET, solvent dyes are practically the only option that delivers both high light transmittance and vivid color saturation.
Transparent engineering plastic pellets and molded parts colored with solvent dyes
Transparent plastic pellets and molded parts colored with Aolong solvent dyes — clear, evenly shaded and free of specks.
Compared with pigments, solvent dyes offer three key differences:
- Higher transparency: molecular-level dissolution, no dispersed particles, more uniform light transmission
- Higher color strength: less dosage for the same shade, better cost efficiency
- Smaller batch-to-batch variation: even dissolution means more consistent color reproduction
II. 4 Key Indicators Before You Choose
1. Heat Resistance (Melting Point)
Engineering plastic processing temperatures are generally above 200°C, so solvent dyes must not decompose or change color at processing temperature. Heat resistance is usually judged by melting point:
| Product | Melting Point | Typical Applications |
|---|---|---|
| Solvent Red 135 (SR 135) | 318°C | High-temp engineering plastics, PET spinning |
| Solvent Orange 63 (SO 63) | 320°C | Fluorescent orange, PET/Nylon spinning |
| Solvent Yellow 114 (SY 114) | 264°C | PC / PS / PET general purpose |
| Solvent Red 179 (SR 179) | 255°C | Nylon 6 spinning |
| Solvent Green 28 (SG 28) | 245°C | Engineering plastics, spinning |
| Solvent Blue 67 (SB 67) | 220°C | Spinning, indoor products |
Note: melting point and heat resistance are not exactly the same thing. For example, Solvent Red 207 (SR 207) has a melting point of 243°C but a heat resistance up to 300°C; Solvent Yellow 114 (SY 114) melts at 264°C with heat resistance also up to 300°C. When selecting, always use the heat resistance rating, not just the melting point.
2. Light Fastness
Outdoor or long-exposure applications (automotive parts, outdoor signage) demand high light fastness. Most Aolong solvent dyes achieve Grade 7-8 light fastness at 1/3 standard depth:
- High light fastness (7-8): SR 135, SY 114, SV 59, etc., suitable for long-term outdoor use
- Good light fastness (6-7): SB 67, etc., suitable for indoor products and spinning
- For extended outdoor exposure, we recommend consulting Aolong for a customized UV-resistant formulation
3. Solubility and Compatibility
Solvent dyes need to be compatible with the resin matrix and disperse evenly. Aolong solvent dyes have excellent solubility in organic solvents, with a typical dosage of 0.1%–2.0% (adjusted by target shade depth), ensuring no color specks and consistent, stable coloring.
4. Migration and Regulatory Compliance
For food packaging, cosmetics packaging and children's products, pay attention to migration and regulatory compliance (e.g., food contact materials, toy safety standards). Because solvent dye molecules are smaller, migration risk is relatively higher. Aolong can provide compliance evaluation and formulation advice for specific applications.
III. Aolong's Six Color Series at a Glance
Aolong Chemical's solvent dyes cover six major color groups — Red, Yellow, Blue, Green, Orange and Violet — with 30+ specifications covering almost all transparent engineering plastic color matching needs:
🎨 Red Series
- Solvent Red 135 (SR 135): standard yellowish red, 318°C melting point, excellent heat and light resistance — first choice for PET spinning and blow molding
- Solvent Red 179 (SR 179): yellowish red, 255°C heat resistance — designed for Nylon 6 spinning
- Solvent Red 195 (SR 195): bright bluish red, excellent light and weather fastness — recommended for spinning
- Solvent Red 207 (SR 207): economical reddish blue, heat resistance up to 300°C
💛 Yellow Series
- Solvent Yellow 114 (SY 114): bright greenish yellow, 300°C heat resistance — general purpose for engineering plastics and spinning
- Solvent Yellow 93 (SY 93): greenish yellow, suitable for various PS grades (not recommended for ABS)
- Solvent Yellow 98 (SY 98): fluorescent greenish yellow for striking fluorescent effects
💙 Blue Series
- Solvent Blue 67 (SB 67): phthalocyanine greenish blue, spinning and indoor decoration
- Solvent Blue 35 (SB 35): bright greenish blue, high color strength
- Solvent Blue 45 (SB 45): reddish blue, highly recommended for PET spinning and blow molding
- Solvent Blue 97 (SB 97): high color strength reddish blue, general purpose for nylon spinning
💚 Green Series
- Solvent Green 3 (SG 3): bluish green, for PC and spinning
- Solvent Green 5 (SG 5): perylene fluorescent green, suitable for PS / SAN / PMMA / PC
- Solvent Green 28 (SG 28): yellowish green, general purpose for engineering plastics and spinning
🟠 Orange Series
- Solvent Orange 63 (SO 63): fluorescent reddish orange, for PET and Nylon 6 spinning
- Solvent Orange 107 (SO 107): transparent reddish orange, 255°C heat resistance, highly recommended for spinning
🟣 Violet Series
- Solvent Violet 13 (SV 13): bluish violet, excellent weather fastness, suitable for long-term outdoor use
- Solvent Violet 31 (SV 31): bright violet, engineering plastics and spinning
- Solvent Violet 37 (SV 37): bright bluish violet, excellent heat resistance
- Solvent Violet 59 (SV 59): bluish violet, for PC and spinning, meets long-term outdoor requirements
IV. Three Steps to Lock In Your Grade
Aolong laboratory color matching and quality inspection
The color matching and quality inspection process in the Aolong laboratory keeps color consistent across every batch.
Step 1: Define resin and process
- PET spinning / blow molding → prioritize high-melting-point grades (SR 135, SY 114, SB 45)
- PC / PS / PMMA injection molding → most grades work; match by heat resistance
- Nylon (PA) → watch hydrolysis and heat resistance; SR 179 and SB 97 are common choices
Step 2: Define color and effect
- Fluorescent effect → SO 63, SY 98, SG 5
- High transparency + high saturation → SR 135, SY 114, SB 67
- Long-term outdoor exposure → high light fastness grades (SR 135, SV 13, SV 59)
Step 3: Define dosage
- Light transparent shade: 0.05%–0.3%
- Standard shade: 0.3%–1.0%
- Deep high-strength shade: 1.0%–2.0%
Want to see how these grades perform in real applications? Check out our solvent dye application scenarios.
V. FAQ
Q1: Can solvent dyes and pigments be used together? A: Yes. A common approach is to use pigments to adjust the hue and solvent dyes to enhance transparency and gloss. Aolong can help optimize the blended formulation.
Q2: Do solvent dyes migrate? A: Compared with pigments, solvent dye molecules are smaller and migration risk is higher. For food-contact or long-term storage applications, always run migration tests first. Aolong can provide targeted grade recommendations.
Q3: What are the MOQ and lead time? A: Standard SKUs start at 1kg, custom formulations at 5kg; stock items ship in 7 days, custom in 15–25 days.
Q4: Can I get free samples? A: Yes. Aolong offers free samples to qualified customers. Please provide the target substrate, color reference and process so we can recommend the most suitable grade.
📞 Contact Us
Need free samples, technical documentation, quotations or custom color matching? Contact our sales team or reach us through the following channels:
- Company Name: Aolong Chemical Co., Ltd.
- Email: sales@aolongchemical.com
- Phone: +86 571 86690377
- Website: www.aolongchemical.com
- Address: No. 1788 Jinggang Road, Shushan District, Hefei, Anhui Province, China
Want to review Aolong's full solvent dye product launch? Read Aolong Chemical Launches Comprehensive Solvent Dyes Series.
Aolong Chemical, focusing on thermochromic technology, illuminating the future of functional materials with "color"!