Adhesives Magazine

Ask Dr. Dave

February 1, 2011
Adhesives and sealants troubleshooting tips from Dr. Dave Dunn.

Question: I am researching gluing products and production methods for a customer. I will be bonding polypropylene, polycarbonate, polyethylene or polymethylmethacrylate plastics to a coated aluminum foil. The plastic pieces will cover small compartments containing the customer’s product, and I need to be able to peel away the plastic piece, taking the entire foil piece to which it has been glued without any possibility of failure. I need to obtain around 20 N/cm². I cannot have temperatures over 50°C during the gluing procedure, and I need the adhesive to have FDA approval. What do you recommend?

Answer: I might have recommended a high-performance hot melt for your application, but since you don’t want to exceed 50°C as your application temperature, I think you should look at a cyanoacrylate adhesive. Several FDA-approved cyanoacrylates are available. However, if you choose to use the polypropylene or polyethylene as your substrate, you will need to treat the surface (e.g., plasma treatment or a special polyolefin primer with the adhesive).



Question: We want to adhere PVC to PVC and EVA to PVC without using a cyanoacrylate adhesive. What is the solution?

Answer: PVC can often be a difficult substrate to bond, particularly if it is flexible. Adhesives that give a good initial bond often degrade over time because of plasticizer migration from the PVC. Assuming that you don’t want to handle a solvent-containing adhesive, I would recommend that you look at a tough acrylic adhesive for the application. These adhesives are available as either two-component mixable systems or as a system comprising a low-viscosity primer applied to one surface and the adhesive to the other surface.



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Dunn

Q&A Exchange is written by Dave Dunn, Ph.D., of F.L.D.Enterprises, a technical consultancy and full-service industrial market-research firm specializing in the adhesives, sealants, specialty rubbers and plastics fields. Dave is a former vice president and director of Loctite Corp. and has spent many years in troubleshooting adhesive and sealant problems. Questions for publication should be directed to him at 242 Trails End, Aurora OH 44202; phone 330-562-2930; fax (330) 247-1690; or email DrDave242@windstream.net .