Cyanoacrylate bonding Santoprene

These grades of rubber require priming prior to bonding (see also Section 10.6). Although this makes it a two-stage operation cyanoacrylates are used for bonding Santoprene and silicone rubbers. 

Polychloroprene, nitrile, natural rubber (polyisoprene), styrene butadiene rubber (SBR) and butyl are amongst the types of rubber that can be readily bonded with cyanoacrylates. Ethylene propylene diene monomer (EPDM) and fluroelastomers (Viton, registered trade mark of DuPont) can also be bonded, although only with specific grades of cyanoacrylate. Silicone rubber and thermoplastic rubber (Santoprene, registered trade mark of Advanced Elastomer Systems) can be bonded with the aid of a primer. Typical applications and techniques for bonding different grades of rubber are discussed in Section 10.11. 

Silicone rubber is difficult to bond with cyanoacrylates. The adhesive does not wet the surface properly without special surface treatment, due to the very low surface energy, and therefore will not bond. Polypropylene (PP), polyethylene (PE), polytetrafluoro ethylene (PTFE) and acetal plastics and Santoprene rubber also fall into this category and cannot be bonded without prior surface preparation. 

This primer is recommended for PP, PE, Santoprene and other similar rubbers as well as PTFE. It frequently enables cyanoacrylates to successfully bond polyacetals as well. 

In another application a gel cyanoacrylate used with a primer eliminates unsightly mechanical fixings and bonds a Santoprene finishing strip to melamine ceiling panels of railway carriages. 

One of the most widely used TPV is sold under the trade name of Santoprene and this material has a low surface energy, thus making it difficult to bond with engineering adhesives. Whilst cyanoacrylates with a surface primer give good results (Table 4.15), the failure modes are invariably at the adhesive-Santoprene interface. 

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See also in sourсe #XX -- [ ]

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