Epoxies are also known as structural adhesives due to their high stress loading capability. They are generally used to bond heavy duty materials over long service periods.
There are 3 types of epoxy resins chemically manufactured and used in industry:
Bisphenol A – Bisphenol A is cheaper, less viscous and has a good chemical resistance.
Bisphenol F – Bisphenol F is more viscous than Bisphenol A, has a better chemical resistance and is generally more expensive.
Novalac – Novalacs are very similar to Bisphenol F type epoxies; they are much more viscous, (almost solid) and have a better functionality and higher resistance to a greater number of chemicals.
The grade of epoxy used in a reaction will determine the overall properties of the structural adhesive.
Epoxies can be supplied in one component or two component systems. Two component systems are epoxies which require a hardener to fully cross-link and cure. One component epoxy systems use a latent amine which requires elevated temperatures to initiate the curing process.
Epoxies can be reacted with a variety of curing agents / hardeners to form an insoluble cured cross-linked network. The type of curing agent chosen will depend on the overall properties of the end product.
Types of curing agents include amine, anhydride, imidazole, acids, alcohols and mercaptans.
- Low chemical resistance
- Low shrinkage
- Absorbs mechanical and thermal stresses
- Cheaper than some other methods of structural bonding
- High fatigue resistance
- Can be used to join dissimilar materials together with little surface preparation
- Possibility of poor heat resistance
- Can be brittle
- Hard to break bonds once cured, making repairs difficult
- Can produce a high exothermic temperature when curing
Where are they used?
- Paints and emulsions
- Light weight void fillers
- Truck and body
Still not sure on which type of adhesive to use? See the below blogs for more information. Alternatively, click here to request data sheets for our current products.
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