The flexo fizz redefining raffia bags

The Indian packaging market has long been defined by gravure dominance. For years, the narrative remained unchanged: If a brand owner required high-fidelity graphics, sharp resolution, and consistent long-run performance, gravure was the first candidate. Flexo was suitable for surface printing on coated woven sacks but technically hindered when it came to premium laminated woven sacks.

However, the tide is shifting. Jainam Shah, partner at Flexure Print N Pack, is spearheading a movement that challenges these legacy perceptions. Through a major technical milestone — the successful printing of reverse-printed BOPP laminated woven sacks, Flexure is proving that flexo is no longer just an alternative; it is a superior solution for the modern supply chain.

The raffia revolution

Raffia bags, or BOPP-laminated woven sacks, are the workhorses of the Indian industrial and agricultural sectors. Traditionally, these bags fell into two categories. The first is the 'coated woven sack,' where a woven fabric is coated with a PP film and surface-printed. While economical, its surface is rough, the graphics are dull, and their barrier properties are ultimately compromised. The second is the premium 'BOPP-laminated woven sack.' This construction involves reverse-printing on a BOPP film to protect the ink and provide a high-gloss, premium finish.

Until now, this was the exclusive domain of gravure. "Till date, premium raffia packaging has been available only in gravure. It was never available in flexo," says Shah. The barrier was not the press, but the chemistry. Flexo's inks were fundamentally incompatible with the extrusion lamination process used for raffia. When molten PP were applied over flexo inks, the bonding failed. "In flexo, the cost of printing plates is less compared to rotogravure cylinders. The changeover happens quickly, handling and storage of plates is relatively easier, and the print quality can be equal or better than gravure," Shah says.

The breakthrough came through a collaboration between Flexure Print N Pack and Ahmedabad-based Navrang Machinery. During Plastindia, the duo showcased a reverse-printed BOPP bag produced entirely on flexo.

Engineering a circular economy

Beyond the visual upgrade, the move to flexo-printed raffia solves a sustainability puzzle. Standard laminated bags often rely on multi-material structures and adhesives that make recycling difficult. "We made it a PP-family pack, a bag that can be recyclable," Shah explains. They used a BOPP film, a PP extrudate, and a PP woven fabric, bonded by the newly developed specialised chemical layer rather than traditional adhesives. This "mono-material" approach aligns with global pushes for circularity while maintaining the 15-20 kg burst strength required for fertilisers, rice, seeds, animal feeds and a host of other commodities.

Navrang's anchor coating unit is not an accessory to the lamination process — it is the process. Positioned inline between the printing station and the extrusion lamination point, it performs a sequence of operations that change the surface chemistry of the printed film and make a permanent bond possible.

According to Bhagirath Parmar, technical director of Navrang Machinery, the true revolution in this process lies in what happens immediately after: The inline anchor coating unit. He says, "Without this, achieving a permanent bond between the ink layer and the molten PP at production speed is simply not possible." He believes that the anchor coating unit is not a workaround, it is a purpose-engineered solution to a problem that had, for years, prevented the full commercial adoption of reverse flexo printed BOPP film in the woven bag segment.

Adding to this, Parmar says, "Reverse printing on flexo is, in itself, a well-established practice. Laminating that printed film with woven PP fabric, introduces a challenge of a different order." He says the two substrates belong to different material families, and at the speeds and temperatures demanded by modern extrusion lamination, standard adhesion mechanisms are insufficient.