Patrick ButlerTUFNOL – From 1960 to 1980
In the early 1960s, the management of TUFNOL launched a major program to develop a range of innovative materials, using the very best versions of the newer types of resins which were commercially available at the time. These included epoxy resins, melamines and silicones, each of which has unique advantages, particularly in their electrical properties.
Since the beginning, the electrical industry had always made use of laminates for insulating components and, as electrical and electronic equipment became more sophisticated, designers wanted ever higher performance and greater temperature resistance.
A sizeable R & D team was brought together at TUFNOL in Birmingham and, from 1965 onwards, a whole series of new materials was released. So many new grades were introduced that the use of brand names was discontinued and grade numbers were used for each of the new grades. First were the ‘modified epoxide’ grades, including ‘TUFNOL Grade 6F/45’. These were quickly followed by a series of materials made from woven glass fabric, including four epoxy glass grades, two silicone glass grades, a melamine grade and an amazingly strong grade using a type of resin called ‘buton’ which is no longer manufactured. Although many of these grades have now been developed further into newer types, or discontinued, this phase of development provided the foundations for the modern, high performance TUFNOL range available today.
The modified epoxy Grade 6F/45, in particular, became an outstanding success. Its exceptional combination of electrical performance, wear resistance, dimensional stability and superb machinability was not matched by any other type of material. Competitors could not offer anything to match its performance and it took TUFNOL into even more new and innovative applications.
One of the most detailed development projects undertaken in the late 1960s and early 70s involved a new material made from polyimide resin. Laminates made from thermosetting resins do not melt at higher temperatures, but they do steadily degrade and lose strength if the temperature is too high. Polyimide resin material is used for applications where it has to survive exposure for long periods to higher temperatures than other rigid plastics will survive. To develop a material like that, it is necessary to keep prototype materials at raised temperatures for prolonged periods before testing them, which involves considerable effort and expense. The result was another world-beating grade, which effectively pushed out the leading edge of applications for which engineering plastics could be used.
