Instant Bonding Epoxy Technology

Epoxy adhesives are composed of epoxy resin, curing agents, and catalysts with modifiers and additives. Bisphenol A-based epoxy resin, bisphenol F-based epoxy resin, novolac type epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl amine epoxy resin, glycidyl ester epoxy resin, and cycloaliphatic epoxy resin are typical epoxy resins. Polyamine, modified polyamine, mercaptan, phenol, anhydride, tertiary amine and imidazole compounds, and cationic initiators are typical curing agents and catalysts. Epoxy adhesives are supplied in both one-component and two-component packages depending on the curing agent used and the curing method applied. Typical room temperature cure epoxy adhesives, thermal cure epoxy adhesives, UV cure epoxy adhesives, and new trends in epoxy adhesive technology developments are described.

UV cure cationic epoxy adhesives are composed of epoxy resins and cationic photoinitiators with additives and modifiers. Cycloaliphatic epoxy resins are the main epoxy resins used for cationic epoxy formulations. Oxetanes are often combined with epoxy resins to improve curability and adjust viscosity. Cationic photoinitiators are all onium salts, composed of an organic cation with an inorganic anion. UV cure cationic epoxy adhesives can be cured quickly via UV light radiation and have been very successful in electronics assembly and general bonding applications. UV cure equipment, formulating, testing, and evaluation of UV cure cationic epoxy adhesives are described.

UV and thermal dual cure hybrid epoxy adhesives are composed of partially acrylated epoxy resin, acrylates, free radical photoinitiators, epoxy resins, and latent curing agents with modifiers and additives. The acrylate components are cured momently via light radiation and thus can instantly fix the bonding materials at room temperature. Their epoxy components can be cured at the post-thermal cure stage to achieve satisfactory adhesion performance. Dual cure hybrid epoxy technology has been very successfully used in electronics assembly and general bonding applications.

Snap thermal cure epoxy adhesives are typically one-component epoxy composition, comprising epoxy resin, a new type latent curing agent, and an accelerator with modifiers and additives. Snap thermal cure adhesives can cure very fast at certain elevated temperature conditions and have been very successfully used in semiconductor packaging and electronics module assembly applications.

Induction cure epoxy technology is based on the induction heating method. Induction heating is a very fast, highly efficient, and noncontact heating style. Induction heating works mainly on bonding applications on conductive metal materials or using specially designed induction curable epoxy adhesives. The induction cure principle and equipment, induction cure epoxy chemistry, and induction cure applications are described. In addition, laser cure epoxy adhesive technology and weld bonding epoxy adhesive technology have been briefly introduced.

Snap ambient cure epoxy technology is based on two-component room temperature fast cure epoxy adhesive systems, including fast room temperature cure epoxy adhesive, cyanoacrylate hybrid epoxy adhesive, and UV and room temperature cure epoxy adhesive. Their chemistry, cure behavior, key features, and applications are introduced.