These are intended to provide FDF members with guidance on curing times (or setting times) for the material prior to first food contact, whilst maintaining the safety and quality of the packaged food.
Flexible packaging materials for the food industry are often multi-layered, the different layers performing different food packing functions.
Isocyanate-based adhesives might be used to bond together these layers to create a high performance specification.
A spokesperson at the FDF explained that "isocyanate-based adhesives consist of two components, which - when mixed - react and cure to form a stable polyurethane layer capable of bonding together plastics, films, paper, foil, metallised films and other materials."
"If mixing of the two components is not managed correctly the adhesive will not cure at all, resulting in a situation where the two materials are not bonded and uncured adhesive could 'ooze' from the cut end of the laminate."
Normally, the laminate would not be used because the materials have not bonded.
However, in the unlikely event that the materials were used there would be potential for it to contaminate the food.
It is important therefore that the adhesive is fully cured before food contact is allowed.
Food contamination problems have reduced in recent years, following a number of legislative developments in 2001.
According to the FDF spokesperson, the EU Directive 2001/62/EC (which amended Directive 90/128/EEC) relating to plastic materials and articles intended to come into contact with foodstuffs, introduced a Specific Migration Limit (SML) for aromatic amine contamination, based upon toxicological studies and detection limits, of 0.02mg/kg in food or food stimulant.
This SML was then incorporated into Commission Directive 2002/72/EC (as amended).
The Flexible Packaging Association, now part of the UK Packing and Films Association, has a code of practice which was originally issued in April 1998.
This was supplemented in May 2001 and consolidated in another guidance document issued in October that year - FPA Guidelines for Laminating with Isocyanate Containing Adhesives.
The FDF confirms that since 2001 there have been a number of packaging developments leading to a range of solutions on the market available to manufacturers.
Isocyanate-based adhesive laminates remain a good high performance specification product.
The FDF explains that these guidelines provide an overview of the relevant EU and US legislation, an outline of the basic chemistry and use of isocyanate-based adhesives, and include simple controls that all users of such materials should follow.