Sealing technology manual for the process industry - Flavoring agents

In addition to the demanding cleaning processes, flavoring agents in the food industry require an equally careful se- lection of the right material. The various flavors affect the material resistance very differently. Especially peach and tropical fruit flavors as well as orange oil can result in prob- lems with regard to material resistance. Flavoring agents consist of various chemical ingredients. Therefore a classification based on their elastomer-dest- roying potential is difficult, even more difficult than for CIP cleaning agents, for example. In addition, the ingredients which are dangerous for elastomers may potentiate their effect or, conversely, may greatly attenuate each other. It is very difficult to gain systematic knowledge here. Traditionally, FKM is used in these media because FKM has excellent resistances to aliphatic and aromatic hydro- carbons as well as oils and fats. FKM can also be used in me- dia such as essential oils and citrus flavorings, whereas EPDM swells a lot due to its high proportion of non-polar ingredients. Since most flavoring agents in addition contain aldehydes, ketones and carboxylic acids, which are known to be harmful to elastomers, there is sometimes no other FLAVORING AGENTS IMMERSION RESULTS OF EPDM, FKM, FLUOROPRENE® XP, HNBR AND VMQ IN ORANGE OIL EPDM FKM FLUOROPRENE® XP HNBR VMQ 24 H 96 H 24 H 96 H 96 H 336 H 672 H 24 H 96 H 24 H 96 H 150 100 50 0 –50 –100 volume in % elongation at break in % tensile strength in % Change in % VMQ and EPDM materials clearly swell far too much in orange oil. Even the swelling behavior of HNBR exceeds the tolerable limit. Fluororubbers, on the other hand, are very resistant. alternative but to resort to FDA-compliant perfluoro- elastomers. Fluoroprene® XP, with its significantly better chemical resistance compared to an FKM, can be an inter- esting alternative to this solution. At any rate, what is important in terms of reliable material recommendations are well-grounded resistance tests. In order to be able to make a reliable assessment of the suitability of an elastomer, not only should the physical in- fluences through the usual tests of mass and volume changes be used here, but also the no less hazardous chem- ical effects of the media on the mechanical properties of the material. These can be determined through comparative measurements of elongation at break, 100% modulus and tensile strength. Because even in dilutions as low as one tenth of one percent, flavoring agents may lead to partly fatal changes in the tensile strength of elastomers. APPENDIX PRODUCT PORTFOLIO MATERIALS RESISTANCE & PURITY ENGINEERING PLASTICS ELASTOMERIC MATERIALS TECHNICAL FUNDAMENTALS INTRODUCTION 57

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