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What Temperature Limits Apply to Adhesives?

August 27, 2013
Question 

In reading 21 CFR §175.105, there is no mention of temperature limit. Does this mean products compliant with 175.105 can be used at any temperatures? I also noticed that §177.1390 and §177.1395 indicate higher temperatures for laminate structures. Does this mean lower temperatures could not be used and be said to be compliant with 177.1390 & 177.1395?

Answer 

The U.S. Food and Drug Administration (FDA) has cleared the use of substances listed in Title 21 of the Code of Federal Regulations (C.F.R.) § 175.105 for use in adhesive formulations intended for the packaging, transporting, or holding of food, subject to certain limitations. While, as you point out, there are no temperature limitations, the adhesive must be separated from food by a functional barrier or be subject to other limitations. As temperatures increase, the effectiveness of the functional barrier may decrease to the point it is no longer effective. It is the responsibility of the food packaging stakeholder to determine whether a true functional barrier exists, or that the adhesive components otherwise do not transfer to food. Potential for migration of the packaging material may be assessed by considering the package structure and the exposure conditions anticipated for the package based on the intended conditions of use or, in some instances, through diffusion modeling or migration testing.

Components of multilayer structures that are not separated by a functional barrier and are used above room temperature must be the subject of either 21 C.F.R. § 177.1390 (for applications above 250°F, such as retorting) or 21 C.F.R. § 177.1395 (for applications from 120°F through 250°F, such as steam-sterilization and hot fill), or an effective Food Contact Notification (FCN) that covers the intended use. Generally speaking, FDA would not object to the use of a laminate complying with one of these regulations from being used at lower temperatures.