Manufactured through the reaction of glycol and an isocyanate, polyurethane is an organic compound with particularly good moisture- and corrosion-resistance characteristics. Thus, polyurethane sealant is useful in both industrial and commercial applications. Additionally, polyurethane is often used as a heavy-duty adhesive, as well as a coating.

A polyurethane sealant may be pressed, layered, sprayed, or brushed onto joints. However, the most common method of application is with a caulk gun. Most poly sealants are sold in 10-ounce (295.74 milliliter) tubes that will fit the common caulking gun.

As well as being resistant to moisture, chemicals, and corrosion, polyurethane sealant is noted for its flexibility. A common problem with joints is the expansion and contraction of the joint. Polyurethane sealants, with their inherent resiliency, are particularly resistant to cracking due to movement of the joint materials.

Polyurethane sealants are available as either one- or two-component compounds. Since the typical residential user of a polyurethane sealant desires ease of use, the basic residential polyurethane sealant is a one-component product. This means there is no need to mix ingredients prior to use.

The typical polyurethane sealant is hydrocarbon-based. However, with the advances in water-based polyurethane technology, effective water-based, or latex, polyurethane sealants and coatings are now available. These water-based polyurethane products are noted for their low-odor, low-variable organic compound (VOC) content, and ease of application and cleanup.

In addition to producing an excellent sealing compound, polyurethane, both water-based and oil-based is often used as a wood coating. The identical factors that are beneficial in a polyurethane sealant contribute to its effectiveness as a poly coating. Polyurethane’s resistance to abrasion, its scuff resistance, makes the product a superior wood-floor coating.

A quality polyurethane sealant will adhere to masonry, wood, concrete, steel, aluminum, vinyl, and most plastics. Its flexible, yet durable finish not only protects these vulnerable materials, but, when used as a coating, provides a gleaming, blemish-free finish, as well. Obviously proper application methods must be used to achieve the desired results. Polyurethane coatings work especially well as an anti-corrosive on metal products. Some experts even recommend polyurethane coating over powder coating for protecting metal, though a textured finish, which many people require, is difficult to achieve with polyurethane coatings.

One well-known trade name for polyurethane sealants, and especially polyurethane adhesives, is Liquid Nails®. Though aimed primarily at the residential market, products manufactured by this company include both residential and industrial polyurethane caulking and coatings. This is only one of many firms that manufacture urethane products, including poly sealants.