Evaluating squeegee materials for quality and performance on press is one of the keys to successful screen printing. This article describes material formulations, essential vocabulary, and criteria for making effective comparisons.
By James Elliot
Many in the screen-printing industry assume that a squeegee is a squeegee is a squeegee. Printers’ lack of knowledge or concern about squeegees is tragically ironic, given how critical squeegees are to the successful application of the process. Even those who pay attention seldom invest the same effort in educating themselves about squeegees as they do for mesh, ink, or emulsion.
Yes, there are marked similarities among squeegees. But even if we limit the discussion to polyurethane squeegees, the scope of available formulations and the resulting balances of performance and cost can be extreme. The printer’s goal is to find which of those balances fits his definition of value. Getting a better handle (yes, the pun is intended) on reaching that goal requires knowledge about the different formulation groups, key terminology, and important criteria for practical evaluation. A good place to start is with the development of squeegee materials.
Probably 95%, or more, of printing squeegees used today are of some form of polyurethane, or urethane for short. Many materials can be squeegees, but the first popular choice was rubber. The term squeegee rubber is still used even though squeegee urethane or even squeegee blade would be more accurate. Natural rubber was used first, but rationing and material shortages during World War II spurred both the need for and development of synthetic alternatives to many materials—rubber among them. One of the new materials was polyurethane, which was developed by Bayer in Germany. However, some time would pass before polyurethane gained acceptance for use as squeegees.
The shift in the US gravitated toward materials that bore more resemblance to natural rubbers, which also remained in use once supplies were restored. These products seemed more familiar and were of lower cost, which seemed appropriate because screen printing was still a fairly crude process with very few technical performance demands. Next, ink systems began to evolve, using increasingly aggressive solvents and resins. Since that time, the performance needs for squeegees have continued to be influenced by developments in inks.
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