Glycol ethers regulations

The kidneys filter waste products from the blood as urine, regulate blood pressure and liquid volume in the body and produce hormones for making red blood cells. Heavy metals (e.g. cadmium and lead) and organic solvents (e.g. glycol ethers used in screen printing) can restrict the operation of the kidneys possibly leading to failure. 

The copolymerization between trioxane and suitable comonomers (ethylene oxide, 1,3-dioxolane, diethylene glycol formal, 1,4-butane diol formal in amounts of 2-5% by weight) is performed using cationic initiators. The cationic initiators could be Lewis acids, such as BF3 or its etherate BF3Bu20 which was used, for example by Celanese (the mechanism of this reaction was studied in detail [163,164]) or protic acids such as perchloric acid, perfluoroalkane sulfonic acids and their esters and anhydrides. Heteropoly acids were used and also a series of carbenium, oxocarbenium salts, onium compounds, and metal chelates. To regulate the molecular weight chain-transfer agents, such as methylal and butylal, are added. 

The solvents in pump sprays are limited to alcohol-water mixtures and are, therefore, not as complex as the solvent-propellant mixtures of aerosols. Generally, ethyl alcohol is the primary solvent, and water the secondary solvent. In some cases, small quantities of propanols or even glycols are also used. The solvent and, of course, the pump spray system largely determine the spray characteristics of a given product, and spray characteristics are very important to the functional character of the product [54]. The solvent-propellant systems of today s hydrocarbon aerosol hairsprays used outside the United States generally consist of alcohol combined with hydrocarbons such as isobutene, butane, or propane and virtually no water. For low-VOC systems, dimethyl ether is the propellant of choice. For additional details on aerosol propellants for hairsprays, see the previous discussion on VOC propellants and the article by Root [53].The solvent-propellant in both aerosol and pump sprays contains the VOC and presents the apparent environmental problem. As stated, the CARB regulations for 1999 of 55% VOC present the target that has stimulated research and development in this area. 

Most of these additives do not have significant regulation issues other than those previously discussed such as the ethylene glycol and ethylene-glycol-based alcohol ether inclusion on the HAP list. The response has been to switch to similar compounds prepared from propylene oxide instead of ethylene oxide. The VOC of a white exterior house paint containing typical examples of the additives noted above is 0.196 kg VOC/liter excluding water [4(h)]. 

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