Series "Innovative printing and paper technology" (3): With the new Planamelt adhesive system, Planatol Adhesive GmbH breaks fresh ground between the cost-favourable ethylene vinyl acetate (EVA) hotmelts and the high-quality polyurethane (PUR)-based hotmelt.
After a development period of nearly two years, the company succeeded in adapting this solution which is well-established in the packaging segment to the graphic arts industry.
The idea: A new adhesive system which is suited for the existing hotmelt systems, allows the binding of heavy paper grades and also features the necessary flexibility for variable runs in digital printing. Despite high quality it should be noticeably more cost-favourable than polyurethane (PUR) hotmelts. With Planamelt, Planatol Adhesive in fact presents an extremely low-odour hotmelt adhesive whose pull resistance value of up to 13 N/cm makes it predestined for the adhesion of heavy paper grades up to 200 g/m2; at the same time, this adhesive system, which is suited for spine and side gluing, can be used for heavily printed paper thanks to its oil resistance. In addition, it maintains its adhesive properties even after multiple heating cycles. According to the manufacturer, PLANAMELT is suited for nozzle and roller application, and it can be processed in one-shot and two-shot procedures.
The technology: With PLANAMELT, Planatol Adhesive pursues a third path between EVA and PUR hotmelts. The system is based on the so-called metallocenes which are well established in the packaging segment due to their adhesive strength on difficult surfaces and their temperature resistance. Other advantages: during processing, hotmelt neither forms strings nor can it gel or encrust. In addition, the amounts that need to be applied are smaller than with EVA hotmelts of a comparable price level. According to calculations of Planatol, it achieves nearly the quality level of high-quality PUR systems especially on heavy grade paper at 50 per cent of the process costs.
Facts:
• Clean adhesion of heavy grade paper up to 250 g/m². Pull resistance values nearly at PUR level: 13 N/cm (grammage: 80 g/m²) 11 N/cm (grammage: 135 - 200 g/m²)
• Thermal stability: ~ 2000 mPas at 170°C, ~ 3500 mPas (150°C), ~ 7000 mPas (130°C)
• Compatible with commonly used hotmelt systems (nozzle or roller application). Delivery in the form of granules in 25 kg sacks
