摘要:
Mechanically attaching articles made from composites has problems due to the difference in properties of the composite in the x, y planar direction and the z perpendicular direction, this results in different properties between the composite and the attachment member such as differences in coefficients of thermal expansion which can weaken the joint further leading to differences in moisture uptake which can further reduce the strength and robustness of the joint. The invention relates to the selection of the position of a joint in order to reduce such problems and to operating the moulding process in a way that improves the provision of mechanical attachments such as bolt holes.
摘要:
A fast cure epoxy resin system is provided that upon curing has a Tg no greater than 140° C. and a Phase angle below 20° at a temperature of 140° C. or below, and prepregs and mouldings based on the system. The resin formulation matches the reactivity of the resin to the amount of curative and hardener employed.
摘要:
(57) Abstract: The present invention concerns a process for the production of wind turbine structures. In the process, a stack of prepregs is located inside a vacuum bag. Each of the prepregs comprises a mixture of fibrous reinforcement and from 20% to 85 wt % of an epoxy resin of EEW 150 to 1500 and containing from 0.5 to 10 wt % of a curing agent. The curing agent comprises a urea curing agent and an imidazole curing agent, and is free of dicyandiamide. The epoxy resin is cured by application of an externally applied temperature in the range 70° C. to 110° C. for a period of from 4 to 8 hours.
摘要:
Epoxy resin formulations of a mixture of a liquid epoxy resin and a solid or semi-solid epoxy resin containing a photoinitiator are used as the matrix in prepregs which are cured or partially cured by radiation to avoid the need for thermal cure in an oven. The formulation is particularly useful in the production of wind turbine blades especially in an automated process.
摘要:
A resin composition that is storable at ambient temperatures. The resin composition forms a cured resin when exposed to a curing agent and heated to a curing temperature that is relatively close to ambient temperature. The resin composition includes a a crystalline resin component that is sandwiched between two non-crystalline resin components to provide a zone that is rich in crystalline thermosetting resin. The crystalline thermosetting resin has a melting point that is above ambient temperature, but below the curing temperature. The viscosity of the resin component changes from a high viscosity state to a low viscosity state when the temperature is increased from ambient temperature to the curing temperature.