The request for alkaline washable ink for PET (Polyethylene Terephthalate) and PC (Polycarbonate) drinking water containers points directly to the need for coding solutions in returnable/reusable bottling systems and for improving plastic recycling.
Inks and adhesives used for returnable packaging must be durable enough to survive filling and distribution, yet completely removable in the industrial washing process, which typically uses hot, caustic (alkaline) solutions (often 60°C – 80°C).
Background and Challenges:
A drinking water manufacturer uses 5-gallon (approximately 18.9-liter) reusable containers made of Polyethylene Terephthalate (PET) and Polycarbonate (PC) for home and office drinking water. To meet traceability, batch management, and logistics requirements, production dates, batch numbers, and barcodes must be printed directly onto the container surfaces. However, standard inks are difficult to fully remove during industrial washing processes. Ink residue not only compromises container appearance but also interferes with subsequent refilling operations and reduces the purity and value of recycled plastic.
Prima solution:
Guangzhou Prima Technology Co., Ltd implemented an alkaline-washable Continuous Inkjet (CIJ) ink specifically engineered for reusable packaging. This ink has the following key features:
Excellent Durability:
Resists abrasion, condensation, and mild chemical exposure at ambient to 40°C temperatures, ensuring legible codes throughout the distribution cycle.
Superior Alkaline Solubility:
Completely dissolves within 30 seconds in a standard industrial wash solution (54–57°C, containing 3% sodium hydroxide), leaving no residue or smearing.
Compatibility with PET and PC:
Provides optimal adhesion—sufficient to stay intact during use, yet non-penetrating to avoid permanent staining or premature flaking.
Food-Safe Compliance:
Free of heavy metals and harmful volatile compounds, certified under relevant food-contact regulations (e.g., Regulation (EU) 2023/1442).
Achievement
1.Containers emerge from the wash process looking like new, with a return-and-reuse rate exceeding 98%.
2.Reduced defect rates caused by ink residue, leading to an estimated 15% annual reduction in cleaning costs.
3.Enhanced purity of recycled plastic pellets, strengthening the closed-loop recycling system.
4.Alignment with brand owners’ sustainability goals and ESG (Environmental, Social, and Governance) compliance requirements.
This Alkaline washable ink can be used in all our CIJ printer, such as PRIMA-B600 CIJ printer, IPS-C240 CIJ printer, IPS-C550 CIJ printer and other brand of CIJ printers.