Professional Polymer Technology
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Polyurethane refers to any polymer that is made up of r […]
Polyurethane refers to any polymer that is made up of repeating chains of organic units joined by urethane links. They form as a result of complex chemical reactions which take a variety of forms. Some of these resulting polymers are made into polyurethane adhesives. These can often be extremely strong, and have become increasingly applicable for household and industrial use.
Polyurethane adhesive is widely used in book binding and woodworking. Polyurethane is a class of polymers that are created from a chain of organic units, joined together with urethane links. It has so many polyurethane adhesive products available. Different chemical combinations result in different properties. The chemical composition can be alerted to produce different levels of stiffness, density and hardness.
The major advantage of a polyurethane adhesive is that it is water resistant. Therefore, it is used to bind books and repair books. The glue has a very low viscosity level, cures within seconds and has a pliable state in room temperature conditions. When used in terms of adhesives, the cure time is the length of time required before the adhesive has bonded the two items together.
Although this adhesive bears the descriptive term “polyurethane,” it has little in common with like-named finishes. However, some polyurethane glue formulations can perform as a sealant. For instance, the gel form is the type frequently used in boat and light aircraft building and repair. Other polyurethane adhesive uses include woodworking, metalwork, and masonry. Construction grade polyurethane adhesives can be used with composite decking, flooring, and concrete.
The strong adhesive factor from this glue stems from its foaming action when it comes into contact with moisture, meaning that it expands as it cures. You could put a misting of water on one surface which is going to be glued, unless the material already contains a small percentage of water vapor (i.e., wood, stone, etc.). Since the glue foams, there is a temptation to wipe or dab the glue as it cures, but this is actually counterproductive. In fact, any excess glue is easier to remove by sanding or scraping after it has cured. In addition, only a small amount of glue is needed and should only be applied to one surface.
Like other glues, polyurethane glue has a limited shelf life, generally six months to one year. You can refrigerate it for a longer use. It’s also worth remembering that since this type of glue reacts with moisture, it will also react to the moisture on skin. So it is vital for you to put on gloves when you work with it.
One more safety caveat - Polyurethane glue - http://www.joyachem.com/ - should be kept out of reach of pets and children. As with skin, the moisture-activating properties of this glue means that it can swell and cause intestinal blockage if ingested.