A couple of days later, we easily observed some small cracks. Some weeks later, the bottom of the aerosol became convex and we observed discoloration. We were not able to perform analyses on the propellant because of a significant leak. As a result, I would advise avoiding the use of DME as a propellant with plastic cans. Hydrofluorocarbons We performed these tests with a family of liquefied propellants: hydrofluorocarbons. Regulation No. 517/2014 limits the use of these propellants in Europe. Indeed, all aerosols containing propellants with a GWP higher than 150 will be forbidden starting in 2018. We therefore decided to perform the tests with the allowed propellants. The first tested gas was HFC 152a. This propellant is not really used in Europe because it is extremely flammable and is more expensive than hydrocarbons. However, it is considered a VOC in Europe, but not in the U.S. Its GWP is 124. It will be available for use in aerosols in its pure form in Europe from 2018. We also tested Honeywell’s HFO 1234ze. As far as we know, it’s the only non-flammable substitute for 134a. It has a low GWP and it is VOC-exempt in the U.S., but is expensive. To reduce the price, one will be allowed to use a blend of HFO 1234ze/HFC 134a (90/10). The GWP is 148, just below the 150 limit, and it is VOC-exempt and cheaper than pure HFO 1234ze. We performed the last test with HCFO 1233zd. One can’t use this product alone as a propellant because of its low pressure. However, this product is not flammable and it could help replace flammable solvents. As with hydrocarbons, I filled some plastics cans and obtained the results shown in Figure 5. The results are more or less the same than with hydrocarbons. Indeed, the weight loss is less than 1g/year and we didn’t observe deformation of discoloration of the can. The characteristics of the propellant do not change. According to these results, plastic cans seem chemically compatible with HFC and HFO. To conclude, all the tested propellants seem to be compatible with the plastic cans except DME. We advise further compatibility testing of your cans in conjunction with your final formulations. Keep in mind that plastic cans are different than metal cans. Therefore, do not forget to check how your plastic aerosol evolves during a hot water bath test (especially when you use liquefied gases). Indeed, the temperature very much influences the mechanical resistance of the plastic. Spray Inventec Performance Chemicals, Vincennes, France, is part of the Dehon Group and is a distributor of a wide range of propellants in Europe, including hydrocarbons, hydrofluorocarbons (HFC), dimethylether (DME) and hydrofluoroolefines (HFO). Figure 5 26 Spray August 2016
Spray August 2016
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