Duplex Board Grey Product Definition and Structure
Jinqiao Duplex Board Grey is a versatile coated paperboard characterized by its dual-sided color contrast:
Top Surface (Coated Side): Bright white, coated with kaolin or calcium carbonate for smoothness and excellent printability.
Bottom Surface (Grey Side): Uncoated grey, made from unbleached chemical pulp or recycled fiber, providing rigidity and cost-efficiency.
Typical Grammage: 200–450 g/m², available in standard sheet sizes (e.g., 787×1092mm, 889×1194mm) or reels.
Core Materials:
Top Layer: Bleached chemical wood pulp (e.g., sulfate pulp) + coating pigments + binders.
Bottom Layer: Mixture of unbleached pulp, mechanical pulp, or recycled fibers (depending on grade).
Jinqiao's Advantage: Balances cost and performance, suitable for mid-to-low-end packaging needs.
Primary Applications
Due to its cost-effectiveness and print adaptability, Jinqiao Duplex Board Grey is widely used in:
Food Packaging: Biscuit boxes, cake trays, instant food cartons (ensure compliance with food-contact standards like FDA or GB 4806.8).
Electronics Packaging: Phone boxes, small appliance cartons (often paired with cushioning materials like EPE foam).
Daily Necessities & Cosmetics: Laundry detergent boxes, cosmetic packaging (relies on surface printing for aesthetics).
Industrial Products: Toolboxes, component packaging (higher-grammage boards for heavy-duty use).
Limitations: Poor water resistance; unsuitable for prolonged outdoor or high-humidity environments.
Key Quality Criteria and Selection Tips
Critical Technical Indicators:
Whiteness (Top Surface): ≥80% (ISO standard); higher whiteness ensures better color reproduction in printing.
Smoothness: ≥300 seconds (Bekk method); low smoothness may cause ink absorption 不均 (uneven ink absorption).
Stiffness (Bending Stiffness): ≥500 mN·m (A method for 230g/m²); insufficient stiffness leads to box collapse.
Interlayer Bond Strength: ≥1.5 J/m²; prevents delamination during lamination or die-cutting.
Visual and Tactile Inspection:
Appearance: Check for spots, holes, or scratches; ensure the coating is intact.
Texture: The top surface should feel smooth, while the grey side should be free of burrs. Shake the sheet-crisp sounds indicate better stiffness.
Water Resistance Test: Drop water on the grey side; no penetration within 5 seconds signals 合格 (qualified) sizing for food packaging.
Supplier Selection:
Prioritize suppliers with FSC/PEFC certification for sustainable sourcing (Jinqiao offers certified grades).
Request COA (Certificate of Analysis) for grammage tolerance, burst strength, and folding endurance. Always conduct pre-batch sample testing.
Processing and Printing Considerations
Printing Techniques:
Suitable Methods: Offset printing (CMYK for detailed graphics), flexographic printing (for simple designs). Avoid full-coverage solid printing (risks show-through on the grey side).
Ink Requirements: Use fast-drying offset inks; test adhesion with the 3M tape pull-off method.
Surface Finishing: Common treatments include lamination (gloss/matte), UV varnishing, embossing, or aqueous coating for abrasion resistance.
Die-Cutting and Forming:
Die-Cutting Precision: Ensure the board's thickness tolerance (±3%) matches the die design to avoid cracking.
Creasing Quality: Pre-test crease lines for smooth folding without fiber breakage.
Environmental Considerations:
Recyclability: The grey layer's recycled content makes it suitable for eco-friendly packaging (check local recycling guidelines).
Low-VOC Coatings: Opt for water-based coatings to meet EU REACH or China's GB 38507 standards.
Idustry Standards and Compliance
Chinese National Standards:
GB/T 10335.2-2015 (White board paper for packaging)
GB/T 22814-2008 (Test method for coated grey board)
International Equivalents:
ISO 534 (Paper and board-determination of grammage)
ISO 2759 (Paper and board-determination of smoothness by air leakage method (Bekk))
If you need Duplex Board Grey Place contact us
WhatsApp：(+86)18933510649
email：02@songhongpaper.com (Ryan liu)
website：https://www.grayboardpaper.com/
address：(Factory Building) Hengyu Road 4th, Sandong Digital Park, Huicheng District, Huizhou City, Guangdong Province
YouTube：https://www.youtube.com/@SonghongPaperCardboard
LinkedIn：https://www.linkedin.com/in/chen-songhongpaper-561022367/
Facebook：https://www.facebook.com/share/1BkX4E196x/?mibextid=wwXIfr
YouTube：https://youtube.com/@chensonghongpaper?si=ZgFz0baC-R-WRys_
X: https://x.com/songhongpa86818