Views: 35 Author: Best Electronic Adhesives Glue Manufacturer Publish Time: 2022-07-18 Origin: https://www.deepmaterialcn.com/
Considerations for the selection of high temperature epoxy optical adhesive for plastic to metal and glass
When picking an adhesive for high temperature applications, many considerations must be made. At the end of the day, it is all about finding a good high temperature epoxy optical adhesive that works according to the need at hand.
The main thing is the temperature. This has to be at a realistic level. It is important to determine the type of resistance required and choose an adhesive appropriately. Some adhesives have better temperature resistance. If you pick an adhesive with a higher resistance than what is needed, it may affect the thermal cycling capabilities.
The other thing that must be considered is how long the adhesive needs to be exposed to high temperatures. Some adhesives are capable of withstanding 300 degrees for a couple of seconds. However, if you were to increase the exposure time to months, days, or hours, the choice has to be different.
You need to consider the application at hand and whether or not there is a need to withstand sustained temperatures that may be over and above 200 degrees. Usually, the adhesive with a high heat resistance also happens to have high Tg values. This means they can be rigid across the operating range related to temperature. The bonds usually have less given within the thermal cycling applications.
What is Tg?
This is the temperature at which most of the adhesives that are temperature resistant change from a glassy start that is rigid to a more pliable form.
This thermal property can be used as a guideline of how capable an adhesive product can handle sustained exposure to some high temperature. This is to say that an adhesive needs to be in a ductile and rubbery state above the Tg when there is more strength. Below the Tg, the adhesive is more brittle.
There are some exceptions to this relationship between the high Tg and heat resistance. For instance, B staged flexible epoxies, and some silicones don’t follow the ser rules.
Silicones have a unique molecular backbone. The B-stage epoxies have a flexible cure state as well. This is to say that the adhesives have a low Tg but have good heat resistance while still maintaining good flexibility even when the temperatures are extremely high. The B-staged epoxies have a master bond with 35 degrees Celsius Tg, while the service temperature can be up to 260 degrees.
Some applications will use adhesives with operating temperatures more than the Tg bit for short periods or small margins. However, this does not affect the mechanical properties too much to matter.
Tg is one of the best indications of good design practice within high temperature applications. When selecting an adhesive, the expected service temperature also has to be considered. Tg mechanical properties and the different thermal stress concerns also have to be considered.
When picking high temperature epoxy optical adhesives, you also have to think of the curing process. If the room temperature is used, the temperature resistance may be lost. Some of the best adhesives with temperature resistance may need an oven cure, and fixturing may also be necessary. Understanding the application needs can be a great way of determining the best adhesive for you.
For more about the considerations for the selection of high temperature epoxy optical adhesive for plastic to metal and glass,you can pay a visit to DeepMaterial at https://www.deepmaterialcn.com/what-is-non-conductive-epoxy-high-temperature-optical-adhesive-glue-for-electronics-components.html for more info.