13 октября, 2015 
Pokraskin In this section, a guide is given to indicate the performance of several different adhesives for a selection of elastomers and thermoplastic elastomers. Most of the performance data was taken from ‘The Loctite Design Guide for Bonding Rubber’ issued by Henkel Ltd [2] and for more detailed information the reader should refer to this guide.
An adhesive cannot be selected solely on the basis of bond strength information as other factors such as cure speed, environmental resistance and dispensing method will all influence the final choice. The values given for the shear strength are given to provide a general idea of how each of the nine adhesives performed on the particular material. Different performances will be achieved depending on the fillers, lubricants, colourants and anti-static additives within the grade of elastomer.
The nine different adhesives selected for these charts were as follows:
• Three cyanoacrylates (standard ethyl, toughened grade and ethyl + primer),
• One two-part acrylic (a standard methylmethacrylate (MMA)),
• One room temperature vulcanising (RTV) silicone (alkoxy cure), and
• One ultraviolet (UV) acrylic (cure at 420 nm).
The shear strengths given in the tables below are given as a guideline only as invariably substrate failure of the elastomer was achieved, thus making it difficult to make performance comparisons. Using a standard lap shear test method, the elastomers deform all too easily thus introducing peel and cleavage forces into the joint.
In addition, there are also many types of additives and fillers produced by many different companies and some will significantly influence the adhesion to the elastomer in question and so it is recommended that trials are conducted before selecting the most appropriate adhesive for the application.
A brief description of each adhesive is given together with a few general comments on the overall performance of the adhesives.
The alkoxy silicone often showed a strength of 0.4 N/mm2 for many of the elastomers tested but in this case the adhesive has failed cohesively. A silicone adhesive is often used where sealing might be the main priority of the adhesive rather than structural strength.
In the case of the UV adhesive, the elastomer material (invariably opaque) was bonded to polycarbonate and the adhesive cured through the polycarbonate.
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