Coldseal adhesives

The adhesive may be solvent or water-based, hot-melt, coldseal or heatseal and pressure sensitive or chemically reactive. So the solidification process may occur via drying of water or solvent-based adhesives, by cooling of hot-melt and heat-seal adhesives, or by curing of chemically-reactive systems. With two notable exceptions - self-adhesive labels used on items of fruit or vegetables, and heat-sealable layers on packaging films - adhesives are in general not intended to touch the packaged food directly. 

There are two main types of coldseal adhesive and these are based on natural latex or synthetic polymers. They differ from pressure-sensitive adhesives in that they stick only to themselves. They are applied to form dry but gummy adhesive layers on flexible plastic films or paper and can be subsequently sealed together by pressure alone to form wrappers for food items and especially for confectionery. 

If coldseal adhesives are prepared from rubber latex there is the special consideration of latex alergenicity. Although the transfer of latex proteins to packaged food is likely to be very low, if measurable at all, at this time it is difficult to come to any firm conclusions on this topic because of the absence of quantitative data on the extent of migration. 

MOUNTEORT, K., jicKELLS, s. and CASTLE, L. (1999) Investigations of coldseal adhesives for their potential for chemical migration (Final report). FSA Project No. FS 2223. Commission Directive 2002/72/EC of 6 August 2002 relating to plastic materials and articles intended to come into contact with foodstuffs. Official Journal of the European Union (L 39/2). 

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