Thermoset composites are designed to meet the needs of applications that must endure high-impact, demanding environments. They offer outstanding durability, structural integrity, light-weighting, corrosion resistance and cost effectiveness.
Thermoset composites are created by combining a thermoset polymer with a reinforcing fiber, such as glass or carbon fiber. Their strength comes from this combination remaining in a permanent solid state after being cured.
Because of their many benefits, thermosets are being used more frequently to replace metal and traditional plastics in a wide range of products, including wind turbine blades, aerospace materials, jet skis, automotive, electronics, and construction materials like window and door frames, roofing, and cladding.
The Air Bubble Challenge
The extremely viscous nature of thermoset resins and their typical application in high wet film thickness makes it common for air bubbles to become entrapped. In consumer terms, these resins could be compared to a thick maple syrup, where it’s easy to see bubbles. Air bubbles are one of the primary challenges that arise in manufacturing or applying thermoset-based systems.
If not removed, air bubbles develop into pinholes, resulting in porosity increase and defect, ultimately leading to a noticeable reduction in the final part’s overall performance, with additional costs and potential safety incidents for the end user. In a bridge or a car, the compromised part could quickly cause catastrophic failure.
Using Air Release Agents
Air release agents are used to help prevent pinhole defects in composite materials and weakening of the final part, as well as to prevent blisters in gelcoats, surface imperfections and poor appearance.
Lubrizol has developed advanced de-aeration polymers for thermoset resins designed to help remove air bubbles. Solplus™ F-Series air release agents function within the bulk of the liquid, facilitating the coalescence of smaller air bubbles to form larger bubbles that migrate to the surface to be rapidly released prior to curing. The formation of larger bubbles and subsequent rise to the surface significantly reduces the amount of air bubbles in the bulk of the liquid when compared to the formulation without air release agents.
Solplus F-Series technology removes air bubbles rapidly and efficiently, prevents pinhole and defect formation, and can improve mechanical strength and production cycle of composite parts—especially in unsaturated polyester, vinyl ester and epoxy.
Solplus F-Series air release agents reduce surface imperfections and provide good clarity to laminates and composite parts. The technology also provides effective fiber wetting, resulting in improvement of fiber interface and prevention of weakness in the composite structure. Silicon-free, hazard label-free and low- or zero-VOC options are available, as well as FDA food contact grades.
Contact a Lubrizol expert to learn more about the use of air release agents to prevent defects in composite materials.