Servicio de Información Comunitario sobre Investigación y Desarrollo - CORDIS

Resin systems providing reduced tack and more flexible prepregs

The target of reducing the organic solvents contents and levels of free phenol and formaldehyde was to be met by altering the molecular structure of the resin and/ or its weight distribution, i.e. by changing the catalyst, its quantity or percentage, the phenol/ formaldehyde ratio, etc. This rather drastic modification of the resin systems commonly used in the manufacturing of glass fibre prepregs had to take place while the processing and handling properties of the impregnated glass fabrics had to be maintained. The application of impregnated glass fibre fabrics in highly automated production processes is nowadays often compromised by insufficient storage properties of the prepregs. Upon extended storage and increased temperature the prepregs transported in stacks tend to stick to each other.

In order to improve the surface tack of impregnated glass fibre fabrics a number of internal and external additives were tested. A new internal separating agent stood out in significantly improving the surface tack. It was of particular interest to verify that the internal separating agents did not harm the internal bonding of the glass fabric to the abrasive mix, resulting in lower burst strength of the grinding wheels.

The safety aspect of grinding wheels operating at high rotational speed is of foremost importance in any evaluation of these tools. Thus it was necessary for every newly developed resin to pass a test procedure involving the manufacturing process of the prepregs as well as the production of grinding wheels. Consequently, it was ensured that the burst resistance of the grinding wheels was by no means negatively affected by the use of the internal separating agents. The processing properties and long term storage stability of the prepregs manufactured were evaluated and quantified by particularly developed test methods.

In this process, resin systems were designed which provide a wider processing window for manufacturers of glass fibre fabrics and grinding wheels. The tack of the impregnated glass fibre fabric was significantly reduced, while the prepreg maintained sufficient flexibility and workability in automated manufacturing processes. Resin systems imparting improved storage stability and processing properties to the glass fibre prepregs can now be offered to the market. The application of these resins can be envisioned in the production of prepregs for various composite applications.

Información relacionada

Reported by

Hexion Specialty Chemicals GmbH
Gennaer Str. 2-4
58642 Iserlohn
See on map
Síganos en: RSS Facebook Twitter YouTube Gestionado por la Oficina de Publicaciones de la UE Arriba