Does UV Light Cure Epoxy Resin?
Does UV Light Cure Epoxy Resin?
Yes. UV light can cure the epoxy resin. There are two main types of epoxy resin: thermal curable and UV curable. Thermally curable resin is cured using heat, while UV-curable resin uses ultraviolet light.
UV-curing resins are typically classified into two broad categories: acrylic resins and epoxy resins. These resins are cured or hardened by UV irradiation, but the specific reaction mechanism differs between the two types of resins.
Acrylic resins are cured via a process known as radical polymerization. In this process, UV light interacts with a photo initiator molecule to generate reactive radicals. These radicals then initiate the polymerization of the monomer molecules, resulting in the formation of long polymer chains.
The resulting polymer is cross-linked, or bonded, to the adjacent polymer chains, resulting in a strong and durable material.
On the other hand, epoxy resins are cured via cyclic polycondensation. In this process, UV light interacts with a photo initiator molecule to generate reactive radicals. The reactive radicals absorb oxygen from the air to form radical cations that bond with epoxy molecules, creating long cross-link chains.
We should note, however, that these two types of resins can have different reactions and characteristics. Radical polymerization is considered more tolerant of environmental stressors, making it more resistant to moisture and other conditions that degrade other resins.
However, radical polymerization requires a longer curing time than conventional polycondensation due to the extended energy required for polymerization reactions.
UV-curable resins require a relatively long curing time, depending on the material’s thickness. For this reason, it is best to start with a small amount of uncured epoxy so that you can work within a smaller curing time frame.
If too much material is poured at once and has not been completely cured after a short time, it will become too thick to remove from its mold or container.
Why Is My Epoxy Resin Bendy?
The most common reason that epoxy resin is bendy, rubbery, or soft is that it has an insufficient curing time. When the epoxy is mixed, it begins to harden as the molecules start crosslinking. However, full curing can take several hours or even days, depending on the specific formulation.
If the resin is not properly cured, the crosslinking will be incomplete, resulting in a softer, more flexible material. Other reasons for soft resin include improper storage or exposure to heat.
If your resin hasn’t been stored properly, it may be susceptible to degradation from heat or other environmental factors. This can cause the resin to soften and become more flexible.
Another reason your epoxy resin is bendy because you’re not properly mixing the resin and hardener by volume. If you don’t mix them in the correct ratio, the chemical reaction won’t happen properly, and the resin won’t harden correctly.
This will cause it to be bendy and not as strong as it should be. If you suspect that your resin is bendy due to a mistake in the mixing process, make sure that you double-check the mixing ratio of your resin.
Epoxy resin that bends is a result of insufficient curing time. In just 24 hours, ArtResin will have solidified to a 95% cure, however, a full cure (100%) can take up to 72 hours.
During this time, the resin is still susceptible to temperature changes which can cause the material to deform. For this reason, it is important to allow the resin to cure fully before handling or using it for its intended purpose.