Early printing inks relied on solvent-based systems for quick drying and strong adhesion but these prioritised performance over health and environmental concerns. Over decades, the industry shifted toward formulations balancing speed, safety and regulatory compliance amid rising VOC emission standards. Today, innovations in water-based, low-odour and sustainable inks drive this evolution, reducing trade-offs in quality and efficiency.
Early Solvent-Based Inks
Conventional solvent inks dominated printing since the late 19th century, using hydrocarbon solvents and resins for lithographic and flexographic processes. These formulations excelled in adhesion to diverse substrates and rapid drying via solvent evaporation, essential for high-speed production. However, they emitted high volatile organic compounds (VOCs), posing health risks to workers and contributing to air pollution with strong odours.
Limited early focus on emissions led to regulatory pressures, prompting gradual reformulation. Pigments dispersed in aggressive solvents like toluene ensured vibrant colours but increased flammability and cleanup challenges. By the mid-20th century, these inks powered offset and gravure printing but highlighted the need for safer alternatives.
Solvent Systems in Modern Printing
Modern solvent inks incorporate ethanol, ethyl acetate and isopropyl alcohol for faster evaporation and lower toxicity compared to traditional options. MEK-free, alcohol-based variants reduce odours, minimising sensory contamination in food packaging while maintaining adhesion and contrast. These systems achieve extended decap times in inkjet applications through fast solvents and fluorosurfactants, avoiding intermediate slow-evaporating components.
Eco-solvent inks further refine this by using biodegradable carriers with minimal VOCs, suitable for confined spaces without ventilation upgrades. In flexography, precise viscosity control at 19 seconds (B4 cup at 25°C) via temperature management cuts solvent top-ups and shop-floor odours.
Shift to Safer Solvents and Low-Odour Inks
The move to alternative solvents emphasises low-odour, low-VOC profiles without sacrificing print quality. Alcohol-based inks replace harsher solvents like MEK, offering usability benefits and compliance with emission regulations. Water-miscible options and glycol ethers provide wetting on low-energy substrates, bridging solvent and water-based worlds.
Low-odour formulations reduce health risks and improve air quality on production lines. In narrow web printing, they lower flammability due to water content, though transitions require press adjustments.
Growth of Water-Based Inks
Water-based inks have surged, with market value growing at 5.6% CAGR through 2027, outpacing solvents at 1.3%. Acrylic resins enable adhesion on non-porous flexible packaging via advanced crosslinking for resistance to water, chemicals and heat. Regulations on solvent emissions accelerated adoption, especially on absorbent paper substrates where VOCs absorb naturally.
In flexible packaging, wetting agents and faster dryers overcome historical challenges, expanding use beyond paper. Benefits include softer hands in apparel printing and easier cleanup, though longer drying demands more energy.
| Aspect | Solvent-Based Inks | Water-Based Inks |
| VOC Emissions | High | Low |
| Drying Speed | Fast (low energy) | Slower (higher energy) |
| Odour/Health | Strong, risky | Minimal, safer |
| Substrate Fit | Excellent on non-porous | Good with aids on flexibles |
| Cost Impact | Lower energy, controls needed | Dryer upgrades possible |
Trade-Offs: Drying Energy vs. Emissions Water-based inks cut VOCs dramatically but require higher drying energy since water’s higher boiling point demands more heat than solvents.
Sustainability-Driven Developments
Sustainability pushes food-safe, low-migration inks using approved foodstuffs as components, ensuring no toxicological risks even in direct contact. These meet statutory preconditions for primary packaging. Recyclable-compatible inks, like NC-free PU and PVB variants, show no colour degradation in PE/PP streams, approved by RecyClass if under 5% weight. Primers aid deinking.
Printech Case Study: Partnering for Ink Innovation
Printech Middle East, a UAE-based provider of printing solutions, partnered with Siegwerk to distribute advanced flexible packaging inks, enabling regional customers to adopt low-VOC, high-performance formulations. In one collaboration, Printech supported a flexo expansion for Hotpack Global, integrating Siegwerk’s inks with W&H CI flexo machine for superior quality and efficiency in converting Gravure printed job to a flexo printing job for a very well known snack food customer.
This unlocked low-odour alcohol-based inks, reducing solvent use and odours while maintaining adhesion on recyclables, cutting emissions by optimising viscosity via temperature control. The customer achieved 20% faster setups and compliance for food-safe packaging, boosting productivity without quality loss. Printech’s technical consulting ensured seamless implementation, exemplifying the shift to sustainable inks.