Ask Dr. Dave / Columns / Finished Adhesives and Sealants

Ask Dr. Dave: May 2013

Several types of products can provide high electrical conductivity for assembly applications.

Question: We are looking for adhesives with high electrical conductivity for several assembly operations. What alternatives do we have?

Answer: Several types of product can be used, depending on what sort of properties you require in the final assembly, how you prefer to dispense and cure the adhesives, and your required cost effectiveness. For example, some conductive hot-melt adhesives are easy to apply, but they are thermoplastics with limited heat resistance. Hot melts are useful in high-speed, high-volume assembly operations.

The most common conductive adhesives, however, are epoxy-based thermosets. Three types of these adhesives include:

•  One-component, pre-catalyzed, heat-cured adhesives—these are typically cured at 120-180°C for several hours and are available with shelf lives of several months.

•  So-called “snap adhesives”—these pre-mixed, two-component adhesives are used as one-component systems because they are supplied and stored in the frozen state, typically at -20 or -40°C. They are thawed before use and will cure at room temperature or at elevated temperatures; they also give faster cures at lower temperatures than conventional heat-cured epoxies. After thawing, the adhesives have a limited shelf life (often called “work life”) of typically a few hours to one or two days.

•  Two-component adhesives—these materials are very shelf stable, just like conventional epoxy adhesives, and can be cured in minutes or hours at room temperature or elevated temperatures. These adhesives are the easiest to handle from a storage point of view coupled with their ability to cure at ambient temperatures, but have the disadvantage that manual or automated mixing equipment must be used for dispensing.

 In terms of electrical conductivity, most conductive adhesives are silver-filled. The reason for this is that, although the two best metals with the highest electrical conductivity are silver and copper, silver has the intrinsic benefit that its oxide is also conductive, whereas copper oxide is not and will lose conductivity on aging through atmospheric oxidation. Some lower-cost adhesive formulations use silver-coated copper or nickel.

Did you enjoy this article? Click here to subscribe to Adhesives & Sealants Industry Magazine.

Recent Articles by Dave Dunn

You must login or register in order to post a comment.



Image Galleries

ASI April 2014 Photo Gallery

Our April 2014 issue is now available!


ExxonMobil Tackifier Expansion

Dwight Tozer, vice president of ExxonMobil’s Adhesion Industry business, discusses the company’s latest tackifier expansion project with Editor-in-Chief Susan Sutton.

More Podcasts

Adhesives & Sealants Industry Magazine

ASI April 2015 cover

2015 April

Our April issue includes previews of the ASC Spring Convention and Expo and the European Coatings Congress and Show, as well as articles detailing end-use applications in transportation, raw materials and equipment. Check it out today!

Table Of Contents Subscribe

Paid Leave

President Obama recently announced he wants U.S. businesses and the federal government to provide paid sick leave and paid parental leave to all workers. Do you think this is a good idea?
View Results Poll Archive


Handbook of Sealant Technology

The Handbook of Sealant Technology provides an in-depth examination of sealants, reviewing their historical developments and fundamentals, adhesion theories and properties, and today’s wide range of applications.

More Products

ASI 2014 Buyers GuideASI's Buyers' Guide

Annual purchasing resource for equipment used in the manufacture/formulation of adhesives, sealants, pressure sensitives, tapes and labels and for application of finished adhesives. 


facebook_40px twitter_40  youtube_40pxlinkedin_40 google+ icon ASI 30px

Clear Seas Research

With access to over one million professionals and more than 60 industry-specific publications, Clear Seas Research offers relevant insights from those who know your industry best. Let us customize a market research solution that exceeds your marketing goals.