Epoxy Resin Curing Process: Tips and Tricks for Optimal Results

Epoxy resin is a thermosetting polymer that is known for its strong adhesive properties and high resistance to chemicals and temperature changes. However, in some cases, the curing process of epoxy resin may take longer than expected. This can be due to a number of factors, including:

• Temperature: Epoxy resin curing is exothermic, meaning it generates heat as it cures. Low temperatures can slow down the curing process, and in extreme cases, can cause the epoxy to not cure at all. On the other hand, high temperatures can speed up the curing process, but they can also cause the epoxy to cure unevenly, resulting in a weaker bond.
• Mixing time: Mixing time can also affect the curing time of epoxy resin. The two components of epoxy resin, the resin and the hardener, must be mixed thoroughly and evenly to ensure proper curing. If the epoxy is not mixed well, it may not cure properly, or it may cure unevenly, leading to a weaker bond.
• Humidity: High humidity levels can also affect the curing process of epoxy resin. Humidity can cause the epoxy to cure more slowly or unevenly, which can lead to a weaker bond.
• Mixing Ratio: Epoxy resin typically comes in two parts, a resin and a hardener. Mixing the two components in the wrong ratio can also cause the epoxy to cure more slowly or unevenly.
• Impurities/contamination: Any impurities on the surface or inside the epoxy or the mixing tools can affect the curing process. Water, humidity, Solvents, oil, or even finger prints can prevent the epoxy from properly curing.

Impurities or contamination can affect the curing process of epoxy resin by changing its molecular structure and slowing down the curing process.

When impurities such as dust, oil or fingerprints come in contact with the epoxy resin, they can interfere with the chemical reactions that occur during the curing process. These impurities can act as inhibitors, preventing the proper formation of the cross-linked polymer network that is responsible for the strength and durability of the cured epoxy. This can lead to a weaker bond, discoloration, or improper curing of the epoxy.

Impurities can also disrupt the chemical balance of the epoxy resin, causing the curing process to slow down or stop altogether. This is because the hardener and resin must react in a specific proportion to cure properly. The presence of impurities can change this balance, slowing down or preventing the curing process.

It’s always important to ensure the surface and tools are clean and free of impurities prior to using epoxy resin. Clean the surfaces with a clean, dry cloth and degreaser, if necessary, and any tools used to mix the epoxy.

The epoxy curing process could be affected by many different things. When we mentioned a curing time on the Technical Data Sheet, it is always an average based on R&D results, laboratory and field testing.

The right conditions for epoxy to cure normally vary depending on the specific product, but in general, epoxy resins cure best at temperatures between 72-74°F (22-24°C) and at relative humidity levels between 40-60%. Temperature plays an important role in the curing process, as epoxy resin is a thermosetting polymer. Low temperatures can slow down the curing process, and in extreme cases, can cause the epoxy to not cure at all. High temperatures can speed up the curing process, but they can also cause the epoxy to cure unevenly, resulting in a weaker bond.

Relative humidity can also affect the curing process of epoxy resin. High humidity levels can cause the epoxy to cure more slowly or unevenly, which can lead to a weaker bond. In general, it’s best to avoid using epoxy resin in environments with high humidity levels.

Another important factor is the presence of impurities, such as dust, oil or fingerprints, on the surface to be bonded or on the mixing tools can affect the curing process and lead to a weak bond or improper curing.

The importance of the mixing ratio and mixing time have also been previously addressed. It’s always recommended to refer to the manufacturer’s instructions, as different products may have different recommendations and curing time may vary depending on the application and intended use of the epoxy.

Additionally, it’s important to remember to always use fresh, undamaged and unopened containers for the resin and hardener, as the age of the product can affect the curing process.

We also collect feedbacks from customers. The curing process could be slowed down or stopped at some point by many factors:

1.  Ratio not precise (weight or volume)
2.  Mixing process isn’t done properly causing resin mix not being 100% homogeneous, so the molecular chain is not fully closed causing less SHORE D (hardness), less heat resistance and soft spots.
3. Disorder the weight mixing ratio (100A/42B) in volume or the volume mixing ratio (2A/1B) in weight. Specific densities of parts A and B are often different so it changes the appropriate ratios.
4. An oversight of taring your container on the scale so it modifies the mixing ratio in weight.
5. Not using a straight side container so the measurements in volume might be affected because of the container angles being smaller at the bottom and larger at the top.
6. Temperature, each degree F/C under 72F/22C will slow down the curing process by 15-25% depending on the mass, therefore it can take longer for the resin to fully cure.
7. You pour less volume/thickness than the recommended CHILL EPOXY™ system.
8. The design of the table. Small sections will take more time to cure.
9. The use of the wrong part B for the CHILL EPOXY™ part A product.

In conclusion, epoxy resin is a versatile and strong adhesive known for its resistance to chemicals and temperature changes. However, the curing process can be affected by a variety of factors, including temperature, humidity, mixing ratio, impurities, and age.

Temperature and humidity play a key role in the curing process. Epoxy resin cures best at temperatures between 72-74°F (22-24°C) and at relative humidity levels between 40-60%. High humidity levels or low temperatures can slow down the curing process or lead to a weaker bond.

Mixing ratio and mixing time are also important factors. The correct mixing ratio of the two components is critical for proper curing. Mixing the epoxy for a sufficient amount of time ensures proper mixing and activates the curing process.

Impurities such as dust, oil, or fingerprints can affect the curing process by interfering with the chemical reactions and changing the molecular structure. They can lead to a weaker bond, discoloration, or improper curing.

To ensure proper curing, it’s important to consult the manufacturer’s instructions and to control the environmental factors and ensure the surface and tools are clean and free of impurities prior to using epoxy resin.

Each CHILL EPOXY™ product was formulated by Polymeres Technologies INC for specific application. One or two products can’t do it all even if some epoxy sellers try to convince you…results speak by itself. If you underpour a specific system, the exotherm curve will change on the lower level (less energy to link molecules) and it will take longer to cure. However, it will reach its final cure but with a longer time.

Thank you for reading this text and taking the time to learn about the factors that can affect the curing process of epoxy resin. I hope you found the information provided to be helpful and informative. If you have any further questions or need additional information, please feel free to ask.

If you have any additional questions or would like more information on how to properly use epoxy resin and the factors that can affect its curing process, please don’t hesitate to contact us at support@polymerestechnologies.com. Our team of experts is happy to assist you and help ensure that you get the best results when working with epoxy resin. We look forward to hearing from you.