Propylene glycol ethers are organic compounds produced from the reaction of propylene oxide with alcohols that are base catalysed. Alcohols include but are not limited to methanol, ethanol, propanol, butanol, and phenol. Higher glycol ethers can be produced from the subsequent reactions with additional propylene oxides.
These compounds are commonly used as coupling agents in paints and as solvents and are also materials for producing coatings, resins, inks, and cleaners.
Compared to ethylene glycol ethers, propylene glycol ethers offer coupling advantages, low toxicity, increased electrolyte solubility, and excellent wetting ability.
Propylene glycol ethers have safer metabolic activities compared to ethylene glycol ethers.
The reaction of one mole of an alcohol with one, two, or three moles of propylene oxide produces propylene glycol ethers.
Propylene glycol ethers use comparable handling procedures that are similar with other common industrial solvents. These can be stored in carbon steel containers. However, if there is slight discoloration or there is trace iron contamination, phenolic-lined drums of stainless steel tanks should be considered as storage tanks.
Gasketing and seals should use polymers such as Teflon, polyethylene and polypropylene. Compatibility should be verified in the selection of such materials for the gasket or seal.
The following should be avoided when storing propylene glycol ethers—contact with air, copper and copper alloys, Buna N, butylene, and neoprene, and aluminum and aluminum alloys.
One of the largest application areas of propylene glycol ethers is the protective coatings. Coatings formulators, resin manufacturers, and coating applicators apply these in protective coatings for applications in industry, automotive, and in architecture. They are also used in cleaning since they provide an extensive combination of basic physical and performance properties for formulations in cleaning.
They are also used as high-performance industrial solvents for paints, inks, and other various applications. New product development and reformulations have used these as solvents.
Polyethylene glycol ethers can be used for different applications that other glycol ethers may not be used for the same purpose. They do not produce toxicological effects that are connected with the use of certain ethylene glycol ethers. Propylene glycol ethers do not produce the same effects as these other glycol ethers.
Polyethylene glycol ethers provide good solvency for a various resins that include epoxies, acrylic, alkyds, polyesters, nitrocellulose, and polyurethanes. Low toxicity, reduction of surface tension, and good solvency for both polar and nonpolar materials is provided by these for cleaners. They are also used in the manufacture of laminates and in semiconductor processes that are used to make circuit boards in the electronics industry.