Common Precautions for Dry Composting with Polyurethane Adhesive

When using polyurethane adhesives for dry laminating, the key points are to apply the adhesive properly, spread it evenly, dry it thoroughly, and ensure a strong bond. There is no need to remember too many complicated numbers. Just focus on these few points and it will be simple, easy to understand and practical. 

 

First, for the glue application, it is essential to follow the specified ratio to mix the main agent and the curing agent together. Start by stirring the main ingredient, then add the curing agent and stir evenly. After that, let it stand for a while to release any bubbles inside. Do not use too much glue; prepare it as needed and use it immediately. Otherwise, the glue will lose its effectiveness over time and will not stick properly. The solvent used to dilute the glue should not contain excessive water or alcohol; otherwise, it will affect the glue's performance and cause the glue layer to become sticky. 

 

Then comes the gluing process. The glue must be applied evenly, without any missed areas or glue lumps. Otherwise, there will be defects when the materials are bonded together. Choose the appropriate rollers to ensure that the glue can be evenly spread on the substrate. There is no need to deliberately measure the amount of glue applied; just make sure it covers completely without any blank areas. 

 

Next comes drying and bonding. After applying the glue, it is essential to thoroughly dry it. Gradually increase the temperature and let all the solvents evaporate. Otherwise, the remaining solvents will have an unpleasant smell and will affect the bonding effect. During the bonding process, the roller temperature and pressure should be moderate. The surface of the substrate should be wiped clean, without water or impurities. Otherwise, bubbles and white spots may occur, and the bonding will not be strong enough. 

 

Finally, it comes to curing and the environment. The fully bonded products should be placed in a warm room for a period of time to allow the glue to fully cure. The environment should not be too humid; excessive humidity can affect the adhesive's stickiness. The substrate also needs to be protected from moisture, especially for materials that are prone to absorbing water, to avoid affecting the bonding effect.