What are the major differences between epoxy adhesive and other common adhesives like polyurethane, RTV silicone, MS, polysulfide? What is its main advantages and disadvantages compared to others?
Epoxy resin system shows a typical characteristic of thermosetting while polyurethane, silicone, MS are thermoplastic. From molecular structure perspective view, epoxy resin after being cured has a 3D rigid backbone while main chains composing thermoplastics is flexible, that explains why these materials show elastic properties in nature and have been found in applications which require high tensile elongation with certain strength.
Main advantages of Epoxy Adhesives:
Good mechanical performance
Waterproof and weathering capability
Resistance to chemicals, anti-fungus
Suitable for joining various materials like metals, ceramics, woods, most plastics, bricks.
Disadvantages of Epoxy Adhesives:
Low toughness, vulnerable to impact
In certain cases, it takes a relatively long time to cure
When refer to epoxy adhesives, high tensile and shear strength (at least 10MPa)are often mentioned. These indicators mainly describe its mechanical properties which are major concern when adhesives serve for structural bonding or strengthening purpose. Besides other indicators like Young’s module, compressive strength, bend strength as well as resistance to impact or thermal shock are also commonly seen in product TDS, depending on specific application.
Since epoxy adhesives are commonly for structural uses, so in cases where strong structural strength or high durability (like waterproof, good weathering capability, chemical resistance,) or low volume shrinkage are the main considerations, epoxy adhesives are a wonderful option. However, in cases where sealing or joints making is the main purpose, epoxy adhesives can also work well as other types of adhesives can do.
One basic rule for properly using 2-K epoxy adhesives is to blend part A and part B at a recommended weight ratio and mixthoroughly to make sure curing agent reacts fully with epoxy resin. To realize that aim, certain mixing tools are recommended for customers. You can consult our customer service center for further information. Another rule is to take precautions to avoid direct eye or skin contact with adhesives, as there are some volatile chemicals which could endanger user’s health.
Epoxy adhesive can cure at low temperature with proper curing agents and some co-catalyst. Depending on actual curing agents being used, it can cure at room temperature, or won’t cure unless at high temperature or sometimes just need another form of activation energy source, for example UV radiation.
Although some volatile chemicals in the formulations, epoxy adhesives are generally safe after being fully cured since the reaction is carefully adjusted. And even some may stay in excess, they are basically locked-in by solid 3D system.
Zhijiang now has developed epoxy adhesives product squad in these years which now goes beyond traditional construction into industrial application areas. Take the auto application for example, we now have developed a series of structural adhesives which are widely used in Body-in-White (BIW) workshop of vehicle producers. Another epoxy adhesive which can cure within 5 minutes at high temperature now find use in white appliance production field. FT-603 is a 2-K adhesive but packaged in a single 400ml cartridge which are designed for general DIY use.
FT602 is a 2K room-temperature curing epoxy adhesives, which is formulated for construction use. It targets bonding metal components and large marble plates which constitute stone curtain. FT602 can also satisfy other application purposes like simple bonding, structural reinforcement, gap filling and chemical anchoring.