Process for stabilizing hypophosphite salts
The current invention relates to a process for stabilizing a hypophosphite salt, comprising the step of heating the hypophosphite salt at a temperature of between 150 and 370° C. during a sufficient period of time to prevent the formation of a dangerous quantity of phosphine in their application as FR in polymers and a flame retardant polymer composition comprising a polymer and 0.1 to 30 weight percent based on the total weight of the composition of the hypophosphite salt thermally stabilized by the above process.
1. A process for stabilizing a flame retardant consisting of hypophosphite salt, comprising the step of heating the hypophosphite salt at a temperature ranging from 150 to 370° C. in an inert atmosphere.
2. The process of claim 1 , wherein the temperature ranges from 190 to 290° C.
3. The process of claim 1 , wherein said heating step is performed for a period of time ranging from one minute to 40 hours.
4. The process of claim 1 , wherein said process comprises heating the hypophosphite salt in a closed system under inert atmosphere.
5. The process of claim 4 , wherein the inert atmosphere comprises carbon dioxide, argon, nitrogen, or a mixture thereof.
6. The process of claim 1 , comprising heating the hypophosphite salt under atmospheric pressure.
7. The process of claim 1 , comprising heating the hypophosphite salt under a vacuum.
8. The process of claim 1 , wherein the hypophosphite salt comprises a salt of formula:
wherein:
n is 1, 2, or 3, and
M comprises an alkali metal, an alkaline earth metal, aluminum, titanium, or zinc.
9. The process of claim 8 , wherein M comprises calcium or aluminum.