A Case for Careful Cleaning Practices of Thermoset Composites
When working with specialized materials like composite laminates like G-7, understanding their chemical properties is crucial to ensuring long-term performance and reliability. G-7 laminates, made with silicone resins, are valued for their high-temperature resistance and excellent electrical properties. However, their susceptibility to certain solvents can create unexpected challenges.
A Real-World Learning Experience
A perplexing case of delamination in G-7 parts turned out to be caused by cleaning the material with carbon tetrachloride, a chlorinated solvent known to degrade silicone resins. Although many of these solvents are no longer in widespread use, the incident highlights the importance of understanding how petroleum-based products and certain solvents can negatively impact G-7 laminates.
Solvents to Avoid
Petroleum oils, greases, and solvents like benzene, toluene, xylene, and chlorinated solvents—including carbon tetrachloride and trichloroethylene—can attack silicone resins. These chemicals lead to swelling and delamination of G-7 materials, rendering them unsuitable for use in applications where such exposure might occur. Care must also be taken to ensure lubricants, coolants, degreasing agents, or coatings do not contain these solvents.
Safe Cleaning Alternatives
For cleaning G-7 laminates, ethyl and isopropyl alcohol are safe options when used in moderation. These alternatives provide effective cleaning without compromising the integrity of the material.
How G-7 Compares to Other Grades
Unlike G-7, epoxy and melamine-based NEMA grades such as G-5, G-10, G-11, and FR-4 are not affected by degreaser chemicals, including trichloroethylene solutions. This resilience makes these materials better suited for environments where solvent exposure is more likely.
Key Takeaways: Keep it Clean
While G-7 laminates offer many benefits, they require careful consideration of chemical compatibility, particularly during cleaning or maintenance. By selecting appropriate cleaning agents and avoiding harmful solvents, you can ensure these materials perform as intended and maintain their structural and functional integrity.
If you have questions about selecting the right materials or understanding their properties, we’re here to help. Contact our support team or connect with an Atlas Fibre technical specialist to learn more about how different solvents impact material durability.