Henkel recently introduced Loctite Liofol LA 2798, a formulation that was reportedly specifically developed for high-performance packaging applications such as thermal processes like sterilization. It is completely free of (3-glycidyloxypropyl)trimethoxysilane (GLYMO), epoxy silane, and heavy metals. Loctite Liofol LA 2798 has been designed as a modular system. The base component can be combined with different hardeners for specific areas of application: sterilization processes, aggressive filling goods, and hot filling processes. The fields of application range from pet food and medical applications to convenience products.
“Common flexible packaging adhesives in the high-performance segment may still rely on GLYMO as an adhesion promoter,” said Helga Garmann, manager of product development for Polyurethanes Europe. “Henkel, however, has always attached the highest importance to offering clean and uncritical formulations.”
Following the 11th Amendment to the EU Plastics Regulation (EU 10/2011), GLYMO has been assessed as potentially genotoxic. A limit of 0.15 µg/kg has been defined to ensure its safe use for food applications. The substance is explicitly allowed to be used. Nevertheless, it also means the packaging producer has to verify that its concentration, as well as that of its derivates, remains below the specified migration limits under conditions of use.
“As testing is complex, we recommend the use of adhesives that do not contain any GLYMO,” said Garmann.
To provide customers with a solution that is completely free of “substances of concern” in its formulation, Henkel reports that it developed the Loctite Liofol LA 2798 adhesive base for medium-high and high-performance applications. In addition to GLYMO or epoxy silane, the formulation is also free of substances such as neopentyl glycol (NPG), hexanediol, tin, and bisphenol A (BPA), making it safe for fatty foodstuffs, oil fatty acids, and alcoholic contents.
The system is reportedly specifically designed for high-temperature food contact and medical retort applications. Henkel currently offers four hardeners that can be combined with the Loctite Liofol LA 2798 adhesive base. Combinations with the room-temperature-curing aromatic hardeners Loctite Liofol LA 5028 and LA 5036 are reportedly ideal for contents such as dried animal food or hot filling goods. These can be used for boiling and pasteurization, placing this system in the medium-high performance segment.
For high performance, Henkel offers the aliphatic hardener Loctite Liofol LA 7371, which also cures at room temperature and is optimal for 45-min sterilization processes at 134°C. This system has a Generally Recognized as Safe (GRAS) statement, certifying its safety for food applications such as baby foods according to FDA 177.1390.
For packaging and sterilizing liquid, particularly aggressive filling goods such as fatty foods and oily fatty contents like cat food, Henkel recommends a combination with Loctite Liofol LA 5802. This system is designed for processing temperatures of 134°C for 45 min and will have a GRAS statement certifying its safety for food applications according to FDA 177.1390.
According to Henkel, all of these solutions share the properties of excellent filling and good resistance, and ensure that the packaging performs to the highest food safety standards even with aggressive fillings. Due to their high-performance properties, the adhesives are also microwavable, which is especially relevant for packaging convenience food products and ready-made meals.
Additional details are available at www.henkel.de.