Common Issues in Water-Based Ink Printing on Paper Bags

Date: Mar 19 2025 From: Star Color

Water-based ink printing on paper bags is a mature production process. However, manufacturers transitioning from gravure to flexographic printing or switching from solvent-based to water-based inks often encounter various challenges. These issues not only compromise printing quality but also reduce production efficiency and increase costs. Below we summarize these problems and provide actionable solutions to help you overcome printing challenges effectively.

Issue 1: Slow Drying Speed and Low Production Efficiency

Cause Analysis
Water-based inks contain 10-20% water with a typical solids content of 40-45%. All moisture must evaporate quickly post-printing for ink curing. Insufficient drying temperature or low airflow fails to provide adequate heat and air circulation for rapid evaporation. Poor absorbency of substrates like laminated paper or high-gloss cardboard prevents moisture absorption, prolonging drying time.

Solutions

Optimize drying systems using infrared + hot air combination drying at 60-80°C. This range ensures fast drying while preventing paper deformation from overheating.
Maintain airflow ≥15m/s with uniform coverage across printed surfaces to accelerate evaporation.
Use quick-drying inks with solids content >50% (e.g., Zhongzhixing Flexo Water-Based Series). Higher solids content enables faster drying under identical conditions.

Issue 2: Significant Color Deviation and Poor Color Reproduction

Cause Analysis
Insufficient ink color strength or batch instability causes color variations across printed batches. Variations in paper whiteness (≥85% ISO 2470) and ink absorbency (30-50s/100ml ISO 5637) lead to inconsistent color rendering. Improper ink-water balance disrupts ink transfer and color accuracy.

Solutions

Standardize ink testing using spectrophotometers (e.g., X-Rite eXact) to ensure ΔE <1.5. Monitor ink viscosity at 25°C (30-45s via #4 cup).
Select papers with whiteness ≥85% and ink absorbency 30-50s/100ml for stable color performance.
Control ink-water balance: maintain dampening solution at 5-8% with conductivity 800-1200μS/cm for uniform ink transfer.

Common Issues in Water-Based Ink Printing on Paper Bags

Issue 3: Ink Skinning and Anilox Roller Clogging

Cause Analysis
High workshop temperature (>25°C) and humidity (>70%) accelerate ink drying, causing skinning on anilox rollers. Insufficient anti-skinning agents (<0.5-1%) and residual ink after shutdowns exacerbate clogging.

Solutions

Install humidity/temperature sensors to maintain 20-25°C and 50-70% RH.
Add ethylene glycol butyl ether anti-skinning agents (0.5-1%) to retard drying.
Clean equipment with alkaline cleaners (pH 9-10) after >15min shutdown to prevent residue buildup.

Issue 4: Poor Water Resistance and Color Fading

Cause Analysis
Substandard ink film resin (failing ASTM D1308 Class 1) and inadequate crosslinking/UV curing leave porous ink layers vulnerable to moisture.

Solutions

Upgrade to high-water-resistant inks (withstand 30min boiling).
Apply water-based varnish (≥3μm dry film thickness) for enhanced surface protection.
Boost UV curing energy to ≥300mJ/cm² (120W/cm mercury lamp) for full polymerization.

Zhongzhixing Water-Based Inks

High solids content ensures rapid drying and productivity.
Stable color strength minimizes batch-to-batch variation for consistent color accuracy.
Anti-skinning formulation reduces anilox clogging under standard conditions.
Premium resins deliver exceptional water resistance and fade resistance.
Wide compatibility adapts seamlessly to various printing equipment, resolving challenges and enhancing market competitiveness.