What are Glycol Ethers?
A glycol ether is a liquid organic substance which is soluble in water. It is used as a solvent in different industrial and domestic applications. A glycol ether could either be an E-series or a P-series. Glycol ethers provides good long-term stability and shelf-life of products, improve water-based products wetting properties, can work at dilute concentrations, and have little odor.
How are they produced?
Glycol ethers are produced when ethylene oxide (EO) or propylene oxide (PO) reacts with alcohols.
One or more EO or PO molecules are contained in the glycol ether molecules. Methanol, ethanol, propanol, butanol, and hexanol are some of the alcohols used to produce glycol ethers. Equivalent acetate ester forms can be produced by esterification of glycol ethers with acetic acid. There are 30 or more possible combinations that can exist with these products.
How are they stored?
No unusual problems occur with the storage of glycol ethers. They have relatively low freezing points and are very stable organic liquids. Except for DOWANOL EPh and PPH which have a freezing point below 55° F (13°C), heated storage is not required.
At normal storage temperature, most glycol ethers do not present a significant flammability hazard. Vapor pressures of glycol ethers are low. DOWANOL PM, PnP, and PMA are the most volatile glycol ether products which have flash points of 88°F, 118°F, and 108°F respectively.
DOWANOL glycol ethers and acetates and blends of DOWANOL should use storage tanks that are constructed of mild steel, stainless steel, or carbon steel. Aluminum and alloys of aluminum storage vessels should be avoided. DOWANOL products affect plastic tank linings so these should not be used.
What are Glycol ethers used for?
Glycol ethers started to be used in different applications during the 1930s. During the sixties and seventies, the range of applications for glycol ethers expanded. This includes the use of glycol ethers in surface coatings. Without glycol ethers, many water-based coatings would not function like in decorative consumer paints and car painting operations by manufacturers. Wood coatings, coil and anticorrosion coatings use glycol ethers. Other important coating types include adhesives and inks in screen printing. Cleaning products, cosmetics, specialty chemical manufacture, leather goods manufacture, electronics manufacture are other applications in the use of glycol ethers. Other uses include manufacture of agricultural products and in fire fighting foams, and in paper, textile, rubber, and constructions industries. The presence of glycol ethers is crucial in the formulation of products since most combination of components would not be possible if glycol ethers are absent in the reaction.