Determination of gel time and curing time of epoxy resin

This standard is applicable for determining the 25 ℃ adhesive and curing time of epoxy resins with fatty amines and polyamines as crosslinking agents

This standard adopts manual method and references GB/T7193.6-1987 Determination of 25 ℃ gel Time of Unsaturated Polyacetate Resin;

GB/T7193.4- Determination of reactivity of unsaturated polyester resins at 80 ℃.

Experimental term: gel time, the time required when wire drawing occurs in the cross-linking and curing reaction of the sample (at 25 ℃).

Curing time refers to the time required for the sample to reach the highest temperature during the cross-linking and curing process. (The company stipulates that the curing time is the time when the sample cannot be stirred with a stirring rod.)

Experimental instruments: precision electronic scale (sensitivity 0.001g), thermometer (minimum division 0.1 ℃), temperature controlled electric heater, 500m1 straight beaker, 100m1 plastic cup, stopwatch, stirring rod

Experimental steps:

1. Place a beaker containing 150m1 of water into a temperature controlled electric heater and adjust it to 25 ± 0.5. Maintain a constant temperature of ℃.

2. Weigh approximately 60g of resin and curing agent in a 100m1 plastic cup in proportion, quickly place them in the beaker, start the stopwatch, and stir the sample evenly.

3. Observe every 30 seconds, use the stirring rod to test the flow of the sample, stop timing until the wire drawing phenomenon occurs, and record the time displayed on the stopwatch as the gel time; If the stirring rod cannot stir the sample, stop timing and record the time displayed on the stopwatch, which is the curing time.

Experimental results: Two parallel experiments were conducted for gel time and curing time, and the relative error of the two experimental results was not more than 10%, otherwise the experiment should be repeated. Take the arithmetic mean as the final result of the measurement.