Zany_in_CO
Saponifier
In other words, a fragrance that has a high flash point temperature doesn't evaporate any much faster or slower than one with a low F.P.
In other words, a fragrance that has a high flash point temperature doesn't evaporate any much faster or slower than one with a low F.P.
why do you recommend blending peppermint with an oil with a higher boiling/flash point?
Blending with a high flash point/low VP/ Base note essential oil (or even a fragrance oil) effectively reduces the VP of the blend and hence help the oil last longer.
One thing that some major cosmetic companies do is use fixatives. Which are actually skin safe solvents (for eg, Isopropyl myristate) which are non-volatile and blend with the essential oils before adding to the soap/cosmetics. This helps the fragrance last extremely long comparatively and imparts a longer shelf life to the final product.
Good to know! That's a new one on me! Thanks!One thing that some major cosmetic companies do is use fixatives. Which are actually skin safe solvents (for eg, Isopropyl myristate) which are non-volatile and blend with the essential oils before adding to the soap/cosmetics. This helps the fragrance last extremely long comparatively and imparts a longer shelf life to the final product.
Me too! Also, for smaller batches, I use the take out Panera Bread salad boxes. I punch 2 holes in the box for some air/vapor release and the scent does keep wonderfully.I started storing my EO scented soaps in closed cardboard boxes at about the 6-8 week mark.
On the recommendation of another SMF member, and after reading about the importance of VP and head space when making perfume, I started storing my EO scented soaps in closed cardboard boxes at about the 6-8 week mark. After 4-6 months, the soaps still smell wonderful.
would the conclusions you drew from testing fragrance oils apply equally to essential oils?Because many people think the flash point temperature is related to how fast the fragrance evaporates. In other words, a scent with a lower flash point supposedly will evaporate a lot faster.
The vapor pressure is the property that does predict a chemical's tendency to evaporate quickly or slowly. High vapor pressure = fast evaporation.
Unfortunately, vapor pressure info (and boiling point info) for fragrances is often hard to find. Flash point temperatures are easy to find, however, because sellers have to know the F.P. temps to ship these chemicals safely.
Awhile back, I compared the flash point temperatures and vapor pressures of 55 fragrance oils to see for myself whether there was a useful relationship between F.P. and vapor pressure or not. The fragrance oils had a wide range in the flash point temperatures (from about 130 F to over 200 F), but there were only small differences in their vapor pressures. In other words, a fragrance that has a high flash point temperature doesn't evaporate any much faster or slower than one with a low F.P.
Another tidbit that I thought was interesting is all of these fragrances have vapor pressures that are at least 20 times lower than water and 35 times lower than ethyl alcohol (ethanol, grain alcohol). I (and I'm sure others) have the perception that fragrances evaporate really fast ... but they really don't.
DeeAnna is correct regarding vapor pressure and yes, unfortunately this information is not tested/provided by suppliers. Flash point is mentioned in the MSDS/TDS sheets so is a better way to select a lower vapor pressure oil.
Flash point is a measure of the temperature where the vapour created by a liquid ignites readily. For this to occur sufficient vapour pressure is needed near the surface.
Also fragrance oils have a low vapour pressure due to the solvents/plasticizers added to them. But natural Essential Oils dont have any such additives and the vapor pressure will differ a bit. With citrus/mint oils having a VP (lower flash point) due to higher terpene content.
Blending with a high flash point/low VP/ Base note essential oil (or even a fragrance oil) effectively reduces the VP of the blend and hence help the oil last longer.
One thing that some major cosmetic companies do is use fixatives. Which are actually skin safe solvents (for eg, Isopropyl myristate) which are non-volatile and blend with the essential oils before adding to the soap/cosmetics. This helps the fragrance last extremely long comparatively and imparts a longer shelf life to the final product.
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