The BMW i3’s self-supporting rear seat pan, produced by automotive supplier F.S. Fehrer Automotive using BASF’s Elastolit polyurethane (PU) system, was recognised with an SPE CE award in the “Body Interior” category in 2013. Carbon fibre materials were used in combination with a PU matrix for the first time in a production vehicle. The component integrates a variety of functions, such as a cupholder mount and storage shelf, which helps to eliminate assembly operations and save weight.
Elastolit is said to be characterised by a wide process window, high fatigue strength and damage tolerance. The crash-relevant part fulfils BMW’s safety requirements despite its wall thickness of only 1.4mm.
Cooperation for low-pressure T-RTM technology
Machinery manufacturer Mahr Metering Systems and BASF have been jointly developing material and system solutions for the thermoplastic resin transfer moulding (T-RTM) process for some time. At the Jec, Mahr exhibited an initial prototype of a self-cleaning mixing head that is part of a machine concept for processing reactive polyamide (PA) by means of inexpensive low-pressure RTM technology. The goal is to develop a robust and automatic system with short cycle times that is suitable for high-volume production.
BASF has been optimising its first reactive PA systems for fast production cycles. Its solutions are two-component systems based on caprolactam, an appropriate additive system and fibres with compatible sizings. These systems have low viscosity and long flow paths, compared to other reactive resins, which makes them especially suitable for low-pressure RTM. The two companies hope to facilitate the market introduction of anionic polymerising PA6 for future volume production of structural thermoplastic composite components.
Floating the boat: PA vacuum infusion and B-pillar prototype in high-pressure RTM
Using a 2.6m kayak as an example, BASF and Munich-based industrial designer Jan Haluszka demonstrated that the vacuum infusion technique (Vari) is suitable for manufacturing thermoplastic composite parts from reactive thermoplastics systems. Also on the stand was the first fibre reinforced composite prototype from Volkswagen. The B-pillar reinforcement, produced using a BASF reactive PA system with high-pressure RTM equipment, is 36% lighter than the current steel version.
BASF presented two new materials that can be used in processes for manufacturing components used in wind-based power generation. BASF’s Baxxodur System 6100 is able to offer a new epoxy system for the special requirements of filament winding technology, which is used in the manufacture of rotor blade root segments. The system, which is approved by German Lloyd, claims to exhibit good impregnation characteristics and to have an open time that permits larger part production. Filament winding technology simplifies the production process and helps to reduce manufacturing costs.
In order to attach the root of the rotor blade securely to the wind turbine hub, a fibre reinforced component made from Elastocoat C6226-100 PU resin by means of pultrusion can be used. BASF and Fibreline Composites in Denmark developed this resin to manufacture pultruded rods. Pultrusion allows better alignment of the fibres as well as in-line incorporation of a threaded metal bushing, and delivers consistent production quality and an extremely stable part. Fewer process steps are needed in production. Both the part itself and a 12cm thick root ring manufactured from glass fibre reinforced Baxxodur were exhibited at Jec.
BASF also presented the cross-section of a wind turbine rotor blade that is intended to demonstrate the wide range of products and solutions available from the company for rotor blade manufacturing, from Baxxodur epoxy resin system through Kerdyn PET structural foam and Relest gel coat system, to Elastan semi-structural PU adhesive. The PET foam provides stability under static and dynamic loads and is used inside rotor blades as well as in the transportation, construction and marine industries. Kerdyn is certified by German Lloyd and available in densities of 80, 100 and 115kg/m3.
Next to the rotor blade cross-section was a spar cap manufactured with carbon fibres immersed in Baxxodur on show. Because of their strength and rigidity, these spar caps are being used increasingly for large rotor blades. During the infusion process, the Baxxodur system ensures fast and complete impregnation of the carbon fibre layers, which provides strength and reliability.
BASF’s range encompasses a variety of epoxy resin and hardener systems, which addresses the trend toward larger parts as well as the increasing number of production processes. The use of latent hardeners provides processors a considerably longer processing time while, at the same time, shortening production time by up to 30%, the company says.