1. Polystyrene (PS)

Application Cases and End Products

End Products: Transparent packaging boxes (such as food containers), toys (such as transparent building blocks), disposable tableware (such as cups).

Application Reasons

PS has good transparency and processing fluidity. Common solvent dyes (such as Solvent Red 52, Solvent Yellow 93) can completely dissolve in PS, providing uniform and bright colors, meeting the needs of consumer products for transparency and aesthetics.

Difficulties and Solutions in Application

Difficulties: PS has low heat resistance (heat distortion temperature of about 70-100°C), and the processing temperature (180-220°C) may decompose some solvent dyes (such as azo dyes with low heat resistance), leading to color deviation.

Solutions: Choose solvent dyes with higher heat resistance (such as anthraquinone dyes, heat resistance up to 250°C) and control the processing temperature below 200°C. Adding heat stabilizers (such as hindered phenolic antioxidants) can also reduce decomposition.

2. ABS (Acrylonitrile Butadiene Styrene)

Application Cases and End Products

End Products: Housings for home appliances (such as TV housings), automotive interior parts (such as decorative strips), electronic product buttons.

Application Reasons

ABS has excellent mechanical strength and surface gloss. Solvent dyes (such as Solvent Blue 104, Solvent Orange 60) can provide uniform coloring, offering translucent or opaque effects, meeting appearance and durability requirements, and avoiding surface defects caused by pigment particles.

Difficulties and Solutions in Application

Difficulties: The butadiene component in ABS is susceptible to UV radiation, and long-term exposure may cause dyes (such as certain azo dyes) to fade.

Solutions: Use anthraquinone solvent dyes with strong light resistance and add ultraviolet absorbers (such as benzotriazole compounds). Surface coatings (such as UV protective paint) can also extend the color life.

3. Polycarbonate (PC)

Application Cases and End Products

End Products: Eyeglass lenses, automotive headlight covers, medical device housings (such as infusion device housings), display screen covers.

Application Reasons

PC has high transparency (light transmittance of about 89%) and impact resistance. Solvent dyes (such as Solvent Green 3, Solvent Violet 13) can maintain its transparency and provide bright colors, suitable for optical and structural applications.

Difficulties and Solutions in Application

Difficulties: PC is sensitive to certain organic solvents, and the solvent carrier of some solvent dyes may cause stress cracking.

Solutions: Choose solvent dyes compatible with PC (such as low-polarity anthraquinone dyes), avoid using strong solvents, and conduct compatibility tests. Use a dry mixing method (directly mixing the dye with PC particles) to reduce solvent contact.

4. Polymethyl Methacrylate (PMMA)

Application Cases and End Products

End Products: Advertising light boxes, automotive taillight lenses, display cabinets, transparent crafts.

Application Reasons

PMMA has extremely high transparency (light transmittance up to 92%) and good weather resistance. Solvent dyes (such as Solvent Red 135, Solvent Yellow 163) can be uniformly integrated, providing bright transparent colors, meeting optical effect needs.

Difficulties and Solutions in Application

Difficulties: PMMA has low surface hardness (about 2H), and it is easily scratched during processing or use, affecting the appearance after dyeing.

Solutions: Apply a hardening coating (such as silicone coating) after dyeing to increase the hardness to 4H or higher, protecting the color and surface. Control the dye concentration at 0.1%-2% to maintain material performance.

Common Challenges and Solutions in Applications

Dye Dispersibility

Solvent dyes need to be completely dissolved in the plastic substrate to avoid color spots. The solution is to use a premixing technique, dissolving the dye in a small amount of compatible solvent and then mixing it with the resin, and ensuring uniformity through high-speed stirring.

Durability

Light and heat may affect dye stability. The solution is to select light- and heat-resistant dyes (such as metal complex or anthraquinone dyes) and combine them with stabilizers (such as antioxidants or UV absorbers).

Processing Compatibility

Different plastics have different processing temperature ranges (such as PS approximately 180-220°C, PC approximately 260-320°C). It is necessary to select dyes that match the processing conditions and adjust according to equipment parameters.