This standard specifies two methods for determining the gel time of phenolic resins using method A and method B at a given temperature of 100 °C, 130 °C and 150 °C under specified conditions. Method A of this standard is applicable to liquid thermosetting resins, method B is applicable to liquid thermosetting resins and low melting point solid thermosetting resins. This standard is not applicable to powdered resins with short gel time, such as mixtures of thermoplastic resins and hexamethylenetetramine. Such resins cross-link as soon as they start to melt in a test tube and become too viscous to give meaningful results. This standard is especially not applicable to resins containing large amounts of low boiling point solvents. These resins boil and evaporate during curing. To measure the gel time of the resin when the catalyst exists, the catalyst should be added in an appropriate proportion, and the type and treatment of the catalyst used should be indicated in the test report.
GB/T 33315-2016 history
2016GB/T 33315-2016 Plastics—Phenolic resins—Determinaiton of the gel time