Polyurethane-based matrix resin for the RTM process

• Three-component resin: resin, hardener & release agent
• Significant faster curing than expoxy products
• Low viscosity for shorter injection times

Composite materials based on glass or carbon fibers combine savings in weight with enormous strength, thus also offering outstanding properties in relation to safety and crash behavior. With its Loctite Max series, the companyHenkel is offering polyurethane-based composite matrix resins that cure significantly faster than the epoxy products usually employed for the RTM process and enable the cost-effective production of composite components under mass production conditions.

The showpiece of the project is a carbon roof segment of the Roding Roadster R1. In addition to Henkel, the KraussMaffei partner network includes the companies Dieffenbacher, Zoltek, Chomarat, Ruehl Puromer, Alpex, Mühlmeier and Roding Automobile GmbH

As-moulded surface finish does not need any further post-treatment

Until now, there have been limitations in the use of lightweight components as they hardly meet the requirements of the automotive industry in regards to cycle times and level of automation. In particular, composite components have been very rarely used for the visible body parts of vehicles, as the requisite post-treatment of the surface for subsequent painting has been too costly and time-consuming.

Working together with KraussMaffei and further partner companies, a new surface resin transfer moulding process has been developed that enables the cost-effective production of paintable composite components under mass production conditions. These components, with a as-moulded surface finish, can be readily used for automobile body exteriors without the need for post-treatment. This has become possible not least to the development of the Loctite three-component polyurethane-based matrix resin system that contains not only the resin and hardener but also a high-performance release agent for easier demoulding. Due to its low viscosity, the polyurethane resins penetrate and impregnate the fiber material more easily and less harshly, thus enabling very short injection times to be applied.

The partner network also includes carbon fiber manufacturer Zoltek and the sports car builder Roding Automobile. The technology showpiece adopted for the development for this process was a lightweight yet high-strength carbon roof segment of the 950 kg sports car, the superlight Roding Roadster R1.

Henkel will showcase the resin and a range of other products at the upcoming #CompositesEurope. The company will also present specially developed benzoxazine resins for injection processes such as VARTM (vacuum assisted resin transfer moulding). A range of bezoxazine prepreg systems is also available. The bezoxazine resins and prepregs offer the particular benefit that they can be stored and transported at room temperature, resulting in a significant reduction in energy consumption.

Main Picture: Its low weight of 950 kilograms means that the Roding Roadster offers significant advantages in terms of driving dynamics, vehicle wear and efficiency (photo: Roding Automobile GmbH).