26 октября, 2015 
Pokraskin Polychloroprene, nitrile, natural rubber, styrene butadiene rubber and butyl rubber can all be readily bonded with cyanoacrylates. EPDM and fluoroelastomers (such as Viton) can also be bonded, although only with specific grades of cyanoacrylate. The silicone rubbers and thermoplastic elastomers will usually require a primer but will also bond with cyanoacrylates.
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Cyanoacrylates are relatively rigid adhesives and so may not be suitable in some applications where a high degree of flexibility is required. The toughened cyanoacrylates do show improved flexibility but are a little slower curing and sometimes
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Table 4.15 Adhesive shear strengths (TPV)
Notes: All shear strengths are given as guidelines only and may vary considerably depending on grade of rubber, fillers, surface finish, etc. |
show slightly lower shear strengths than a standard ethyl grade. However, where an elastomer is to be bonded to a metal, then a rubber-toughened cyanoacrylate might well prove the best adhesive. Note that cyanoacrylates are best suited for non-structural applications and are best suited for temperatures up to 100 °C.
Modified flexible cyanoacrylates (see Section 1.1.1.7) also show improved flexibility (Figure 4.1) but the glass transition temperature of these adhesives is lower and so the hot strength and heat aging properties of these products is limited to around 70 °C.
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Figure 4.1 Nitrile rubber bonded with a flexible cyanoacrylate |
If, therefore, a high degree of flexibility is required at higher temperatures then a two-part acrylic — or silicone-based product may be more suitable.
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