Plastics - Phenolic resins - Determination of reactivity on a B-transformation test plate
1 Scope
This standard specifies methods for the determination of the B-transformation time of phenolic resins at a specified temperature and under specified conditions on a B-transformation test plate.
Two methods are described, each with a different B-transformation test plate:
——Method A: Spherical plate with depressions;
——Method B: Flat plate without depressions.
This standard is applicable to resol and novolak containing curing agents.
Note: The B-transformation transition time of phenolic resins on the B-transformation test plate is usually called “condensation rate”.
2 Principle
The condensation of the phenolic resin is carried out to the B-stage on one of two types of test plate.
3 Method A: Determination on a spherical plate with depressions
3.1 Apparatus
3.1.1 Thermostatic control device, permissible temperature variation ± 0.5°C.
3.1.2 Hotplate, on which the test plate can be fixed in a suitable manner to obtain optimum heat transfer.
Note: No hotplate is necessary if a test plate with an integral heater is used.
3.1.3 Glass rod, 5 mm in diameter, tapering to about 2 mm in diameter at one end.
3.1.4 Balance, scale interval 0.01 g.
3.1.5 Syringe.
3.1.6 Stopwatch, with at least 1 s sub-divisions.
3.1.7 B-transformation test plate, with spherical depressions as shown in Figure 1, with or without an integral heater. Suitable melting salts may be used for accurate control of the heater.
Foreword i
1 Scope
2 Principle
3 Method A: Determination on a spherical plate with depressions
4 Method B: Determination on a flat plate without depressions
5 Precision
6 Test report
