Tethered silicone oligomer coatings for low-friction injection molding surfaces

Overview

This technology delivers durable, slippery, low-energy surface coatings for metal injection molding tools using silicone oligomers that remain tethered to the mold surface but behave like a liquid at elevated temperatures. At temperatures relevant to injection molding, the lightly cross-linked siloxane layer melts to form a self-smoothing interface between the mold and the molded component, minimizing stiction and enabling easy part release. Because the oligomers are chemically anchored to the metal, the slippery character is maintained over repeated molding cycles rather than being lost through transfer or wear.

Technical specifications

• Coating chemistry: Non-polar siloxane oligomers rich in methyl groups, designed with a melting temperature in the range of 200–300 °F so they transition to a liquid-like state under typical injection molding conditions.
• Surface attachment: Siloxane end-groups react with hydroxyl groups on the metal mold surface, forming covalent tethers that anchor the coating and prevent loss during demolding.
• Cross-linking: Light chemical cross-links are introduced after attachment to stabilize the layer while preserving the ability to flow and self-smooth at high temperatures.
• Material compatibility: Silicone chemistry is food-contact compatible and stable up to approximately 400 °F, supporting demanding molding environments.
• Characterization methods: Synthesized oligomers will be verified by NMR and FTIR; functionalized mold surfaces will be characterized by XPS and wetting measurements, with surface condition tracked before and after multiple thermal and molding cycles.

Technology readiness level

The approach is at an early, pre-validation stage. The underlying benefits of low-surface-energy silicones and smooth interfaces for reducing mechanical adhesion are established in other applications, but the specific tethered, thermally activated liquid-like coating for injection molding has not yet been demonstrated. Planned next steps include synthesizing oligomers with the target melting range, demonstrating functionalization and cross-linking on metal molds, and conducting injection molding trials at UMass Lowell with durability evaluation across repeated thermal cycles. The technology is positioned for co-development, sponsored research, and pilot validation with molders, coating partners, and materials manufacturers.