Adhesives Magazine

Ask Dr. Dave

December 1, 2007
December 2007

Question: Can you advise on the best non-toxic, water-based adhesive for leather, rubber and fabric shoe soles, and folding of shoe uppers and linings?

Answer: Traditionally, solvent-based polychloroprene adhesives were used for this application. However, due to legislation on solvent emissions, most manufacturers use water-based systems these days. Water-based polychloroprenes are not as forgiving as their solvent-based counterparts, and you may find it necessary to use a two-component version to maximize performance. Aqueous polyurethane dispersions are another system that you should consider. They are usually applied to the substrates, dried and then heat-activated. Several types of these adhesives are available with different performance characteristics in terms of cure speed, flexibility, etc.

Question: I am looking for a good adhesive for bonding glass to metal. The application is for trim on a lighting fixture. It will be subjected to heat (~100°C) and UV. I currently use a silicone adhesive, but can you recommend anything with a faster curing time?

Answer: You probably have several alternatives. First of all, you could use a two-component silicone that can give you very fast cure times. The drawback to this, of course, is that you will need to invest in and use a two-component syringe/cartridge system or meter/mix equipment. However, the increase in productivity often outweighs the investment required. You might also look at fast-curing epoxies, although some yellowing of the adhesive may occur under UV light. A third alternative is to look at using a fast-curing, two-component acrylic system. This should give you a high-performance system that will be resistant to both the heat and the UV.

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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 .