How Polysiloxane Coatings Beautify and Protect


photos courtesy of PPG protective & marine coatings

When polysiloxane coatings were introduced 25 years ago, they set a standard for performance that remains unsurpassed today. With their exceptional color/gloss retention and superior resistance to corrosion, UV light, abrasion and chemicals, polysiloxane coatings became the industry choice for protection of storage tanks, smokestacks, oil platforms, bridges and other infrastructure applications, as well as for amusement parks, stadiums, cargo ships, aircraft carriers and other marine vessels.

In seeking to advance the technical development of these products, PPG developed its PSX family of polysiloxane coatings, offering three distinct products to meet the color and corrosion-fighting demands of asset owners, architects, engineers and maintenance personnel around the world.


The secret to the performance of polysiloxane coatings can be found in their chemistry—a string of powerful silicon-oxygen bonds. When polysiloxane polymers are created, each silicon atom is bonded to two or three oxygen atoms, causing the silicon to be 50-75% oxidized when the coating is formulated.

Because this oxidation is built into their formulation, polysiloxane coatings are inherently less vulnerable to environmental hazards than epoxy- and acrylic-urethane coatings, which are based on weaker carbon-carbon bonds. The chemistry of polysiloxane coaings yields health and environmental benefits, too, including the absence of isocyanates and low VOC content.


In addition to introducing the first products based on this technology in 1994, PPG owns 16 patents for their continued development. This expertise has enabled PPG to develop a full range of polysiloxane coatings for protective and marine applications, encompassing the following product lines:

PPG PSX 700 and PPG PSX 700SG (Semi-Gloss) Coatings

Designed for long-term protection of steel substrates, these epoxy-based polysiloxane coatings have decades of proven performance in harsh environments.

According to PPG, the “robust formulation and excellent adhesion of the PSX 700 coatings” produce results that “equal or surpass traditional three-coat epoxy- and acrylic-urethane coatings, which require the application of a mid-coat epoxy layer.” For asset owners, this means reliable corrosion performance, color retention and gloss retention with less product, waste and investment in materials, scaffolding, labor and other expenses. When used for maintenance applications, this line of coatings can help return assets to service more quickly than those requiring three coating layers.

PPG PSX One Coating

This coating offers the performance and environmental advantages of polysiloxane coatings as well as ease of application. A single-component, acrylic-based formulation, PSX One is pre-mixed and shipped in cans, eliminating the mixing concerns associated with two-component coatings that require precise blending on the job site.

For touch-up and maintenance applications, PPG can custom-match its PSX One coating to any PSX 700 coatings color. According to the company, cans may be re-opened and reused multiple times, as long as container lids are properly resealed after each use; therefore, pot life is longer. The product’s features include unlimited recoatability and ease of storage to make maintenance projects easier.

PPG PSX 805 Coating

Introduced in 2017, PSX 805 is the latest in PPG polysiloxane technology. Formulated for greater flexibility than traditional polysiloxane coatings, it can better withstand the cracking and stress associated with exterior steel, tank and building applications. The coating also combines the corrosion protection of conventional three-layer coating systems with the labor-saving benefits of two-coat application.

Due to its extremely low-VOC content, the coating meets strict Greenguard emissions criteria for interior spaces. Unlike PPG PSX 700 coatings, which feature a glossy finish, the PSX 805 coating features a durable satin sheen designed to mask imperfections on steel surfaces.

To learn more, visit www.ppgpmc.com or call (412) 434-3802.

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