SEDL / STP / STP247-EB / STP44204S

An Improved Flow Tester for Thermosetting and Thermoplastic Molding Compounds

von Meysenbug, C. M.
Leader, Plastics Section, Staatliche Materialprüfungsanstalt, Darmstadt,

Pages: 14    Published: Oct 1959

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Abstract

All plastics while being molded undergo a conversion in which they become viscous. This is a reversible conversion with the thermoplastic compounds, whereas the thermosetting compounds pass through the B stage (Resitol condition). Molding technique, therefore, is dependent primarily on adequate information about the viscous or flow properties, and useful data have become available in recent years. Several methods have been used in producing these data, among them measurement of the viscosity itself, or determination of the time necessary for molding under a specified pressure. These methods do not give a representative picture; with only a single viscosity measurement they cannot show what really happens during flow under molding.