GB/T 33315-2016 in English

《GB/T 33315-2016塑料 酚醛树脂 凝胶时间的测定》由TC15（全国塑料标准化技术委员会）归口，TC15SC11（全国塑料标准化技术委员会热固性塑料分会）执行，主管部门为中国石油和化学工业联合会。

Plastics - Phenolic resins - Determination of the gel time

1 Scope

This standard specifies two methods, i.e., method A and method B, for determining the gel time of phenolic resins at a given temperature under specified conditions. The test temperatures are 100℃, 130℃and 150℃.

Method A specified herein is applicable to liquid resols, method B is applicable to liquid resols and solid resols with low melting points.

Powdered resins with a short gel time, such as mixtures of thermoplastic resins and hexamethylenetetramine, do not lend themselves to this type of determination. Such resins crosslink as soon as fusion starts and become too viscous in the test tube to give meaningful results. Resins containing large amounts of a solvent with a low boiling point are especially unsuitable for this type of determination. With such resins, a boiling and distillation process takes place as the resin hardens.

It is of interest to determine the time taken for the resin to gel in the presence of a catalyst. The catalyst shall be added in well defined proportions. The type of catalyst used and its treatment shall be stated in the test report.

2 Method A (Manual method)

2.1 Principle

Put the reverse mouth test tube into the oil bath, and stir the liquid resols clockwise in the test tube with a stainless steel rod until the resin becomes gel.

2.2 Apparatus

2.2.1 Thermostatically controlled bath: maximum temperature 200℃; the control precision of the selected test temperature ±0.5℃. The density of the bath liquid, e.g. silicone oil, shall be 1g/cm3±0.1g/cm3.

2.2.2 Reverse mouth test tube: 10mm±0.2mm in diameter and 77mm±2mm in length.

2.2.3 Stainless steel bar: diameter 1.2mm±0.1mm; and length approx. 130mm.

2.2.4 Stopwatch: accurate to 1s.

2.2.5 Iron stand and matching test tube holder.

2.2.6 Disposable syringe.

2.3 Specimen

The specimen shall be sealed and stored at room temperature within 8h, and refrigerated at 0℃~10℃ for a long time. The specimen may be directly used for test without pretreatment.

2.4 Procedure

2.4.1 Perform the test in duplicate, or on a greater number of parallel specimens as agreed between the parties concerned.

2.4.2 The test temperature shall be 100℃, 130℃ or 150℃, as agreed between the parties concerned.

Foreword i
1 Scope
2 Method A (Manual method)
3 Method B (Automatic method)
4 Test report
Annex A (Informative) Precision in ISO 9396: 1997