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Q: Is there a quality check list of food-grade powder coating as per FDA requirements?

With FDA (Food and Drug Administration)-compliant powder coatings there are two ways to have a powder coating meet this requirement. Powder coatings that may come in contact with food products are covered under the US 21 CFR (Code of Federal Regulations) 175.300 "Resinous and Polymeric Coatings. This code provides chemists a "white list" of ingredients that we can use in our powder coating formulas and be acceptable for contact of food products. The ingredients listed allow the formulator to produce either an epoxy or epoxy-polyester based powder coating. More recently a polyester curing agent, tradenamed Primid, has been added to the list. It is important to note that all epoxy, epoxy-polyester, or Primid-based powder coatings are not FDA-compliant for food contact. Only the products that are specifically formulated per the restriction of 21 CFR 175.300 can be considered compliant.

Another option exists for powder coating manufacturers to supply a powder for food contact. This pertains to a formula that is outside the ingredient strictures of 21 CFR 175.300. The powder coating supplier can run specific tests that measure the potential for ingredients to leach out of the cured coating. If the test results fall under a specified limit the coating can be considered compliant.

It is interesting to note that the FDA does not "approve" powder coatings for this regulation. The burden of acceptability rests on the powder coating supplier who states that a particluar powder is compliant to this federal code.

Date asked: 18 November 2009

Q: Dear Mr. Joseph, I am a master's student at in a materials science and engineering program studying about electroless Ni-B coatings on cast iron substrates. I have some problems with pretreatment processes, and I was hoping you can help me with this topic. I cannot find the proper pretreatment steps.

Unfortunately, my expertise lies in the areas of painting and coatings, not plating. However, you may want to check out the online version of the Metal Finishing Guidebook & Directory, especially the chapter on Electroless (autocatalytic) Plating. The online version allows you to search chapters and content by terms, including pretreatment. Hopefully this will provide you with the information you are looking for. Just click on the link above and it will take you directly to the online version, or copy and past the following link into your browser: http://e-ditionsbyfry.com/Olive/AM3/RMF/Default.htm?href=RMF/2008/11/15

Date asked: 14 October 2009

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