Heat Treatment and Polyurea Coatings

The polyurea coating refers to a protective coating added to urethra of rubber or other materials. A urethane coating will protect against friction, abrasion and heat. When properly applied, it will help protect the urethra against cracking during use. Although polyurea is commonly used for flooring, sealants are also used on doors, gutters, skirting boards, cabinet faces, air conditioners and many more applications. The polyurea coating has an added advantage over other sealants: it allows a larger surface area of a small amount of material to be covered with the same amount of material, thus achieving a more cost effective seal.

polyurea coating

The polyurea coating can be composed of several compounds. The first two compounds mentioned above (polyurethane) and amine (monomer) are the major polyurea components. Amine is the major component responsible for the amine structure that produces polyurea. Polyurea is formed by the amine chemical reaction between a specific amino acid and isocyanic acid, in aqueous solution.

In order to apply polyurea coating, it must undergo surface preparation. This involves heat-treating the polyurea coating to achieve a hard, solid, thick and resistant coating. Heat treatment usually employs alkaline solutions (low acidity), quenching (low water resistance) or even a combination of all these to achieve the best results.

An isocyanate (isocyanate) component can either react with the resin blend during heat treatment or prevent further reaction during processing. The most common isocyanate component found in polyurea isocyanates, which react with the resin during heating. Other isocyanates are produced during the heat-treating process itself such as monocyanates, whose main role is to prevent resin re-crystallization. There are various other isocyanates such as diocyanates, triocyanates and polyimides. Isocyanates that cause the resin to re-crystallize include the benzoates, carbides and UV-resistant isocyanates.

Various polyurea systems have different ways of providing protection. Some of them can provide better energy-efficiency through the thermal mass or by reducing infrared radiations. The most common polyurea coating used for thermal mass is heat-treating. In polyurea spray coatings or polyurea vapor coatings systems, the use of UV curing agents can improve upon the heat-treating properties. UV curing agents help speed up the absorption process in the resin thus increasing the drying speed.

Abrasion of polyurea coating is important to get good results and enhance durability of the finished product. The process of abrasion is done using mechanical or chemical abrasion equipment. The mechanical abrasion equipment is used when a smooth and flat surface is desired. The chemical abrasion equipment is used to produce smooth surfaces, which includes in forging, stamping, forging & heat-treating. Both types of abrasion can produce the same results, but are used in different applications.

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