Technical advantages

Covestro’s high-performance polyurethane infusion resin system is especially suited to vacuum infusion production of large wind turbine blades.

This innovative material solution makes lighter, longer and stronger blades possible – and offers several distinct advantages.

Performance facts

  • Durability
    PU infused wind turbine blades display excellent mechanical performance and better fatigue resistance properties than conventional solutions like epoxy.
  • Production safety
    Wind turbine blade production becomes safer with PU infusion resin, as less exothermic energy is generated than with conventional solutions.
  • Production speed
    PU resin’s lower viscosity and better fluidity help to speed up infusion, while the fast curing time means no post-curing is needed. This enhances the efficiency of wind turbine blade production.
  • Design
    Compared to standard epoxy resins used in blade production, PU infusion resin can help optimize blade design and reduce weight, which brings wind blade manufacturers significant benefits. This innovative raw material makes lighter, longer and stronger blades possible.

FAQs

How does PU infusion resin improve productivity?

Polyurethane resin has a lower viscosity and better fluidity than epoxy resin, which can result in a faster infusion speed. When used for thick layers or heavy glass fiber fabrics, the amount of polyurethane resin infused is much higher than that of epoxy resin under the same time conditions.

The fast curing time of polyurethane resin means no post-curing is needed, which enhances the efficiency of wind turbine blade production. The diagram below shows how polyurethane resin can reduce the production time for a spar cap, for example.

How does PU enhance a wind turbine blade’s performance?

The interface bonding performance between polyurethane resin and glass fiber is superior to epoxy with glass fiber. Both matrix (casting) and glass fiber composites (FRP) of polyurethane resin feature much better mechanical properties.

Thanks to optimized design and an improved glass fiber laminate structure it is now possible to manufacture lighter and longer blades.

How compatible is PU compared to conventional raw materials?

Polyurethane resin is compatible with various materials. When working with epoxy resin, structural adhesive and core materials, for example, polyurethane resin displays excellent mechanical properties.

The applications of polyurethane in wind blades can be tailored to customers’ needs. Polyurethane can be used for manufacturing not only the whole blade, but also for spar caps, shear webs or other pre-fabricated PU components, while using epoxy in other parts.

The interfacial shear strength between polyurethane resin and the polyurethane substrate is higher than that between epoxy resin and the epoxy base.

How can society and the environment benefit?

As the power of wind turbines increases, so does the blade length. Since the power output of a turbine is proportional to the area swept by the blades, longer blades yield more power. However, longer blades bring new design and manufacturing challenges. Further investment in R&D for new materials that can meet these requirements is needed, and Covestro is developing solutions that specifically address blade manufacturers’ needs.

The ability to produce lighter, longer and stronger blades helps to make wind turbine blade production more efficient. Covestro is paving the way for this, and thus speeding up the implementation of cleaner, low-carbon solutions.