EN ISO 7327:1997

Plastics - Hardeners and accelerators for epoxide resins - Determination of free acid in acid anhydride (ISO 7327:1994)

Publication date:   Jun 30, 2004

General information

60.60 Standard published   Jun 18, 1997


CEN/TC 249 Plastics

European Norm

83.080.10   Thermosetting materials



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The principle of the method specified is reacting a small amount of free acid present in a test portion of acid anhydride hardener or accelerator with rhodamine 6G to colour the test solution pink, measuring the absorbance of the coloured solution at a wavelength of about 510 nm using a spectrometer, determining the free-acid content from a calibration curve. The method is suitable for most anhydrides except for polyester and oligomeric anhydrides which may give too wide a scatter of results.

Life cycle


EN ISO 7327:1997
60.60 Standard published
Jun 18, 1997


Adopted from ISO 7327:1994 IDENTICAL