New polyurethane sealing material for contact with food

Raku-PUR 31-3173 is suitable for use as a lid sealing material for containers that come into contact with food at room temperature for only short periods and without heating. This new foam gasket based on polyurethane is aimed at manufacturers of canisters, drums and IBC containers for aqueous, alcoholic, fatty, and dry goods.

“The Raku-PUR 31-3173 foam gasket meets the requirements of Art. 3 Regulation (EC) No. 1935/2004 and sections 30 and 31(1) of the German Food and Feed Code (LFGB) in conjunction with Regulation (EU) No. 10/2011 under consideration of the surface/volume ratio and if it is used as part of an object within the meaning of section 2(6) of the LFGB”, explains Dr. Ulrich Nehring from the Institut Nehring laboratory for foodstuffs, consumer goods and the environment in his report.

The two-component soft integral foam Raku-PUR 31-3173 boasts two impressive properties – its compression set of just 2 % and its low water absorption rate of around 5.5 %. After 24 h 50 % deformation and at a temperature of 50 or 70 °C, the cured foam gasket returns to its original form with shrinkage of just 2 %. It therefore has a recovery rate of 99 – 100 % based on EN ISO 1856. To test its water absorption, the two-component soft integral foam was submerged in 10 cm of water for 24 h.

The certification for use in the food industry from Institut Nehring applies to the formulation of Rampf's white foam gasket, which is specially formulated to meet the requirements for contact with food. The system contains no solvents, plasticisers or CFCs/HCFCs. Raku-PUR 31-3173 is available in 30 kg containers and 200 – 1,000 l IBCs.

The polyurethane system can be processed in situ. The two-component sealing material is applied to the component directly with a two-component low-pressure mixing and dispensing system and begins to expand in situ after a cream time of 45 – 80 s. For processing one, two, and multi-component reaction resins, sister company Rampf Dosiertechnik offers systems that can be integrated seamlessly into both existing and new systems for the production of new drums and reconditioning of drums and IBCs.

The new material is a valuable addition to the Rampf group's portfolio of foam gaskets. Rampf Giessharze develops and sells liquid and thixotropic sealing systems, foam and unfoamed gaskets, Raku-Skin foam gaskets made of a soft polyurethane foam core and moulded, rigid and high-pressure foams. The company also offers electro and engineering casting resins, edge and filter casting resins, and two-component adhesives for all key industries around the globe.