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What is the effect of humidity and temperature on the curing of polyurethane adhesives?

What is the effect of humidity and temperature on the curing of polyurethane adhesives? 1. The influence of moisture on curing a. For moisture-curing polyurethane adhesives, sufficient absolute humidity must be maintained during use, so that the adhesive can obtain enough moisture to ensure complete curing. b. For two-component polyurethane adhesives Adhesive, too much moisture will consume too much curing agent, make the ratio unbalanced, affect the curing effect, and then affect the high temperature resistance and medium resistance of the adhesive layer. 2. The effect of ethanol on curing. When the ethanol content in the solvent is low, a small amount of curing agent is consumed, which reduces the crosslinking density and affects the heat resistance and medium resistance. When the content is high, the curing agent is consumed in large quantities, resulting in incomplete curing. Therefore, In the work, it is necessary to choose a solvent with low moisture and ethanol content, and to prevent secondary pollution in storage, transportation and use. 3. The effect of temperature on curing. Polyurethane adhesives can be cured under room conditions, but the curing time is long. In order to shorten the curing time, the temperature can be increased. Increasing the temperature is also conducive to the softening of the initial adhesive and the enhancement of the adhesive. Wetting the surface of the material can increase the contact points between molecules, but if the temperature is too high, the curing is too fast, the stress is not easy to release, and it is easy to cause the later bonding strength to decay. More knowledge about curing and curing of flexible packaging bags can be found in YLTpacking

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