The flexible packaging industry is evolving rapidly, and innovation in material science has become a competitive necessity rather than a luxury. Converters, ink formulators, and brand owners are under growing pressure to deliver enhanced durability, sharper print quality, greater processing versatility, and compliance with increasingly rigorous food-safety standards. Polyurethane (PU) chemistry has risen to meet all of these demands at once.
PU-based inks are steadily capturing global market share, driven by their exceptional resistance to heat, chemicals, and demanding post-processing operations such as pasteurization, boiling, and retort sterilization. Their compatibility with a wide range of substrates — including PET, BOPP, and CPP — combined with flexibility across lamination techniques, makes them the go-to choice for flexible packaging converters in India and beyond.
At UFlex Chemicals, PU ink binder development is grounded in a deep understanding of these industry dynamics. Through advanced polyurethane chemistry and sustained R&D investment, the company has built an application-specific binder portfolio that delivers measurable improvements in print quality, process efficiency, and end-use performance.
UFlex Chemicals’ PU ink binder portfolio
UFlex offers a comprehensive, tiered binder portfolio organised across three core performance categories — Plasticizing, Semi Film-Forming, and Film-Forming — alongside a Specialty Functional grade engineered for demanding aseptic applications. Each grade is defined by clear technical parameters to support precise formulation work.
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Plasticizing PU resin grades
Designed to enhance flexibility and enable efficient solvent release, these grades deliver superior printability and consistent runability on high-speed press lines. Flexpak 5679, with its high solids content and moderate viscosity, is well suited for general-purpose gravure and flexographic applications where strong adhesion and reliable pigment interaction are critical.
Flexpak 5678, characterized by its ultra-low viscosity, is ideal for ink systems requiring precise rheology control, enabling excellent dot transfer, reduced solvent retention, and stable performance at elevated press speeds.
Extending the performance, Flexpak 6002 offers enhanced resistance to deep-freeze conditions, as well as oil and dairy environments, making it particularly suitable for demanding and high-value food packaging applications.
| Product Code | Solids / Viscosity | Key Performance Attributes |
| Flexpak 5679 | ~75% solids / 900–1100 cps | General-purpose flexo /gravure; excellent adhesion and pigment interaction |
| Flexpak 5678 | ~75% solids / 50–100 cps | Low viscosity; good compatibility with NC & NCPU; low solvent retention; excellent dot transfer at high-speed printing; strong bonding with solvent-based, solvent-free, and extrusion laminates |
| Flexpak 6002 | ~50% solids / 300–500 cps | Enhanced resistance to deep-freeze, oil, and dairy environments |
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Semi film-forming PU grades
Striking an optimal balance between flexibility and bond strength, this range is engineered for applications where lamination performance is as critical as printability. Flexpak 5100 delivers high lamination bond strength with a non-yellowing profile, making it particularly suitable for transparent overwraps and clear-window packaging formats.
Flexpak 5300 is specifically formulated for high-opacity white ink systems, offering consistent adhesion across BOPP, PET, and nylon substrates, thereby ensuring reliable performance across diverse flexible packaging structures.
Flexpak 2765, with its moderate solids content and superior hydrolytic stability, functions as a versatile, multipurpose binder. It is well suited for a wide range of ink systems, including overprint varnish (OPV) applications, where durability and stability under varying environmental conditions are essential.
| Product Code | Solids / Viscosity | Key Performance Attributes |
| Flexpak 5100 | ~70% solids / 700–1300 cps | Strong lamination bond strength; non-yellowing performance |
| Flexpak 5300 | ~30% solids / 500–1200 cps | High-opacity white inks; excellent adhesion on BOPP, PET, and nylon |
| Flexpak 2765 | ~37% solids / 500–1200 cps | Superior hydrolytic stability; multi-purpose including OPVs |
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Film-forming PU grades
Engineered for technically demanding applications, this range extends the limits of substrate adhesion, print fidelity, and process compatibility. Flexpak 2754 delivers consistent and robust adhesion across OPP, PET, and nylon substrates—materials that often require careful surface energy management—while also ensuring excellent printability and compatibility with a variety of ink systems.
Flexpak 2756 is specifically optimized for high-speed gravure printing, combining low viscosity with the film strength and integrity required for precise dot reproduction and fine-line definition.
At the advanced end of the spectrum, Flexpak 2757 represents a significant evolution in hybrid binder technology. It integrates retort resistance, high bond strength, and compatibility with extrusion lamination, while also offering improved NC compatibility, enhanced water resistance, greater flexibility, high color strength, and low solvent retention—delivering a comprehensive solution for high-performance flexible packaging applications and supports in GSM reduction with new generation cylinders. A food-compliant solution suitable across all food safety standards and regulatory frameworks.
| Product Code | Solids / Viscosity | Key Performance Attributes |
| Flexpak 2754 | ~30% solids / 500–1000 cps | Strong adhesion on OPP, PET, and nylon; excellent printability; suitable for vinyl & PU inks; good bonding with solvent-based, solvent-free, and extrusion lamination. |
| Flexpak 2756 | ~37% solids / 200–400 cps | Optimized for high-speed gravure printing; low viscosity; high-strength ink systems; good pigment dispersion. |
| Flexpak 2757 | ~50% solids / 800–1200 cps | Retort resistance; high bond strength; compatible with extrusion lamination; improved NC compatibility and water resistance; enhanced flexibility; high color strength; low solvent retention; a food-compliant solution suitable across all food safety standards and regulatory frameworks and supports in GSM reduction. |
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Specialty functional grade: Flexpak 2763
Flexpak 2763 is purpose-built for aseptic packaging—one of the fastest-growing segments in global food and beverage applications. Its key differentiator is its resistance to hydrogen peroxide (H₂O₂), the sterilizing agent widely used in aseptic filling lines for milk pouches, juice packs, and similar liquid packaging formats.
With high solids content and a controlled viscosity profile, this grade delivers excellent film integrity and chemical resistance, ensuring consistent print quality and structural performance throughout the sterilization process. This makes it a reliable solution for applications where hygiene standards, material stability, and process compatibility are critical.
| Product Code | Solids / Viscosity | Key Performance Attributes |
| Flexpak 2763 | ~75% solids / 300–600 cps | H₂O₂ resistance; engineered for aseptic packaging (milk, juice pouches) |
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Performance benefits across packaging ecosystem
The UFlex PU binder portfolio creates consistent, measurable value for ink manufacturers, formulators, and converters alike:
- Broad substrate adhesion across PET, BOPP, CPP, OPP, and nylon, reducing the need for substrate-specific reformulation
- Efficient solvent release supporting faster press-line drying speeds and improved productivity
- Wide resin compatibility with NC, PVB, ketonic, and vinyl systems, enabling versatile blend formulations
- High flexibility and mechanical durability under thermal stress and post-processing operations including heat sealing and sterilisation
- Advanced resistance properties spanning hydrolytic stability, chemical resistance, and sterilisation tolerance across pasteurisation, retort, and aseptic processes
- Non-yellowing performance in transparent and clear-window packaging applications where visual integrity is paramount
These capabilities enable ink manufacturers to formulate with confidence, converters to operate more efficiently, and brand owners to meet stringent regulatory and performance requirements across global markets.
Innovation outlook
The next frontier for PU ink binders sits at the intersection of performance and sustainability. As the packaging industry faces growing regulatory pressure around solvent use, carbon footprint, and recyclability, binder chemistry will play a central role in enabling the shift towards more sustainable ink systems — including low-VOC, water-based, and solvent-free formulations — without sacrificing performance.
UFlex Chemicals is actively developing next-generation binder technologies to meet these emerging requirements, with a particular focus on compliance with evolving global food-contact regulations and the demands of recyclable mono-material packaging structures.
Rajesh Srivastava, executive vice president of UFlex Chemicals, says, “Our focus is on developing solutions that not only address current industry needs but also anticipate future challenges — driving performance, efficiency, and sustainability in equal measure.”Â
