Application Tips – Epoxy Adhesives
Epoxy Adhesives
Both these terms in TDS (Technical Data Sheet) are used to describe the time after which the viscosity of the product roughly doubles making it unuseful for bonding.However, pot life is a function of environment temperature and mass of the epoxy mixed.As a user it is important to carefully observe this property and not onlydepend on values mentioned in TDS.
Performance of an epoxy can significantly improve through correct surface preparation method.Hence when bonding high finish or difficult to bond surfacesor substrates where mold release agents,coatings etc have been used may need surface prepration. Type of surface preparation depends on many factorsand you can contact Elixir-India for quick help, some of the methods can be solvent based cleaner,surfaceabrasion,chemical etching (especially in case of plastics)or chemical wash.
Tg of an adhesive plays an important role when operating environment temperature moves on either of extreme levels.Typically a high temperature applicationdemands high Tg product and vice versa.This is a very critial aspect that can get lost often at the selection stage.If an epoxy adhesive’s TDS does not specify its Tgplease conact Elixir-India.
Unlike a methacrylate adhesive, mixing ratio of epoxy adhesive should be as close to specification as possible.Changes in their mixing ratio can drastically impacttheir performance.We recommend a mixing variation of less than +/-2%
Applications that need large quantity of epoxy to be applied at one go needs carefuly consideration about the exothermic behaviour of the product. Epoxy beingan exothermic product generates heat during cure process,applying large quantity will generate more heat leading to brittle bond.Hence,it is important to uselow exotherm products for such applications.
Typically standard epoxy adhesives form bonds that are hard and very rigid.If your application demands the epoxy to be flexible or softer,then choose to go with modified epoxy adhesives.Refer Modified epoxy section on our webpage.
It is recommended to mix epoxies in small batches to avoid waste and faster curing due to large quantity on account of exothermic reaction.
Generally a cured epoxy adhesive is not easy to clean.The methods you can use are scraping with tools,abrasion and then cleaning with a solvent based cleaner. the other hand cured modified epoxies can be cleaned relatively easily using Loxeal CR5 cleaner.
Epoxy adhesives can be cured rapidly by exposure of heat.Heat cure not only speeds up the curing process but it also improves additional cross linking leading to strongerbond
It is very common for air bubbles to form when manually mixing the epoxy.For some applications these air pockets can be quite dangerous and the best way to avoidair pockets is to stir gently and pour slowly. For critical applications such as space and high end electronics, vacuum degassing or centrifuge can be emplyed to suck out air bubbles.
Modified Epoxy Adhesives
Both these terms in TDS (Technical Data Sheet) are used to describe the time after which the viscosity of the product roughly doubles making it unuseful for bonding.However, pot life is a function of environment temperature and mass of the epoxy mixed.As a user it is important to carefully observe this property and not onlydepend on values mentioned in TDS.
Performance of an epoxy can significantly improve through correct surface preparation method.Hence when bonding high finish or difficult to bond surfacesor substrates where mold release agents,coatings etc have been used may need surface prepration. Type of surface preparation depends on many factorsand you can contact Elixir-India for quick help, some of the methods can be solvent based cleaner,surfaceabrasion,chemical etching (especially in case of plastics)or chemical wash.
Tg of an adhesive plays an important role when operating environment temperature moves on either of extreme levels.Typically a high temperature applicationdemands high Tg product and vice versa.This is a very critial aspect that can get lost often at the selection stage.If an epoxy adhesive’s TDS does not specify its Tgplease conact Elixir-India.
Unlike a methacrylate adhesive, mixing ratio of epoxy adhesive should be as close to specification as possible.Changes in their mixing ratio can drastically impacttheir performance.We recommend a mixing variation of less than +/-2%
Applications that need large quantity of epoxy to be applied at one go needs carefuly consideration about the exothermic behaviour of the product. Epoxy beingan exothermic product generates heat during cure process,applying large quantity will generate more heat leading to brittle bond.Hence,it is important to uselow exotherm products for such applications.
Typically modified epoxies such as the ones mentioned in this section are formulated to form soft and flexible bondlines.These epoxies elimiate the challenges posedby standard epoxies of rigid and hard bondline.
It is recommended to mix epoxies in small batches to avoid waste and faster curing due to large quantity on account of exothermic reaction.
Cured modified epoxies can be cleaned using Loxeal CR5 cleaner.
Epoxy adhesives can be cured rapidly by exposure of heat.Heat cure not only speeds up the curing process but it also improves additional cross linking leading to strongerbond
It is very common for air bubbles to form when manually mixing the epoxy.For some applications these air pockets can be quite dangerous and the best way to avoidair pockets is to stir gently and pour slowly. For critical applications such as space and high end electronics, vacuum degassing or centrifuge can be emplyed to suck out air bubbles.
Heat Curing Adhesives
Single part epoxy of 1K epoxy as they are generally called should be ideally refrigerated.They are very unstable chemicals at higher temperature and exposureto high temperature can lead to loss of physical properties
Performance of an epoxy can significantly improve through correct surface preparation method.Hence when bonding high finish or difficult to bond surfacesor substrates where mold release agents,coatings etc have been used may need surface prepration. Type of surface preparation depends on many factorsand you can contact Elixir-India for quick help, some of the methods can be solvent based cleaner,surfaceabrasion,chemical etching (especially in case of plastics or chemical wash.
Tg of an adhesive plays an important role when operating environment temperature moves on either of extreme levels.Typically a high temperature applicationdemands high Tg product and vice versa.This is a very critial aspect that can get lost often at the selection stage.If an epoxy adhesive’s TDS does not specify its Tgplease conact Elixir-India.
Cured 1K epoxies cannot be easily cleaned,infact it can become very difficult job to do.The methods you can use are scraping with tools,abrasion and then cleaning with a solvent based cleaner.
Though single part epoxy adhesives are already very fast curing when we compare them with two part epoxy,they can be virtually fully cured in seconds byexposing them to induction curing process.Loxeal 4690,4580 are among some of the products that can be cured that way.
