Why do Resins cure quickly in barrels,but slowly after pasting fabric?

Sometimes, such problems happen in the field construction:it is normal for the exothermic of the resin&gels in the plastic bucket, the hardness and surface dry,but the solidification will be very slow after pasting fabric and the wall construction, even after a long time, it is still soft and sticky, especially when the construction environment is low temperature, humidity, thin thickness and the use of vinyl ester resin. The causes of this problem are as below:

1.Polyester resin curing is exothermic reaction. The resin in the barrel is more and the heat release is more concentrated. Gel curing will be faster than the thinning after pasting fabric. Usually, the curing time of thethe mixedresin, gel and additives will be 2-4 times longer than that of the same pure resin. Therefore, the  solidification will be slow after pasting fabric.Please patiently wait for the surface to dry before the next step.

2.The vinyl ester resin reactivity is lower than unsaturated resin, the solidification time of gel is longer after pasting fabric, especially when using high moisture content or cheap methyl ethyl ketone curing agent, it will be more serious (there will be much bubbles after adding the mixed promoted resin). It even appears to be unsolidificated, soft and sticky, which seriously affects the later construction and use. Methyl ethyl peroxide with moisture content less than 3% should be chosen to ensure the later curing.

3.When the construction environmentis with lowtemperature,high humidity and thin coating or surface, it is recommended to use MERICAN231/233 accelerator to accelerate the curing process and shorten the curing time.

4.Excessive moisture content in construction materials such as reinforcement materials, fillers and resins can also lead to such problems.

 

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