8 октября, 2015 
Pokraskin Epoxy resins are usually supplied as one-part frozen pre-mixes or two-part systems. There are numerous formulations; each has its own particular characteristic and can vary in viscosity from a thin liquid to a gel consistency. Epoxies are used as adhesives, coatings and binding resins and have excellent abrasion resistance and chemical resistance. Due to the vast array of fillers and different types of epoxy resin, properties vary substantially. Epoxies are generally strong, and also heat, chemical and abrasion resistant. Many printed circuit boards are fibreglass-filled epoxy. Other applications range from marine coatings and encapsulations to adhesives and floorings.
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The Araldite® series of epoxy resins, manufactured by Huntsman, are perhaps the most well-known, typically two-part systems and these epoxy adhesives would generally be expected to bond well to epoxy thermoset plastics. Cyanoacrylates showed good results in these trials [3], but would not be expected to offer the same durability as epoxy-based adhesives. Note that there are so many different grades of epoxy materials that it is impossible to give specific data (Table 3.2) is intended as a guideline and tests would always be necessary to confirm adhesion performance.
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Table 3.2 Adhesive shear strengths (epoxy resins)
Notes: All shear strengths are given as guidelines only and may vary considerably depending on grade of epoxy, fillers, surface finish, etc. |
Phenolics are one of the earliest bonding agents and are typically heat cured to form a highly crystalline thermosetting polymer. Phenolics have moderate strength compared
to other plastics but have higher hardness and greater rigidity then most thermoset and thermoplastics. They are made up from a reaction between phenol and formaldehyde so are often referred to as phenol formaldehyde or melamine formaldehyde. Typical applications include handles, electrical terminals and switches.
There are many different variants and many have excellent flame resistance and so are used in many public sector applications (mass transit, marine, etc).
Epoxy-based and two-part acrylic engineering adhesives generally bond well to phenolics and roughening the surface was found to be beneficial for the UV-curing acrylics (Table 3.3).
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