国卢生 国生 Propellant is responsible for developing the proper General requirements for propellants pressure within the container,and it expels the Vapor pressure higher than atmosphere product when the valve is opened and aids in the ·No toxicity atomization or foam production of the product. ·Inert Non-flammable,non-explosive ·No color,.no odor Cheap 国丝生一 国生一 ©Type of propellant Advantages ofhydrofluoroalkane (HFA) Low inhalation toxicity Chlorofluorocarbon (CFC) High chemical stability ·High purity Hydrofluorocarbons(HFAs) ·Not ozone depleting ©Disadvantages of hydrofluoroalkane(HFA)） ·Poor solvents Minor greenhouse effect ·High cost 国坠生 Propellants 圈生 Propellants Hydrofluoroalkane (HFA)propellants The pressure of aerosol is critical to its .Tetrafluoroethane(HFA134a) performance.It can be controlled by the type Heptafluoropropane (HFA227) and amount of propellants. Mixture of propellants f f Change vapor pressure C-C-H Change liquid density F- ·Change solvency HFA-134a HEA-227 44 Shanghai Jiao Tong University Propellant is responsible for developing the proper pressure within the container, and it expels the product when the valve is opened and aids in the atomization or foam production of the product. Shanghai Jiao Tong University General requirements for propellants • Vapor pressure higher than atmosphere • No toxicity • Inert • Non-flammable, non-explosive • No color, no odor • Cheap Shanghai Jiao Tong University Type of propellant • Chlorofluorocarbon (CFC) • Hydrofluorocarbons (HFAs) Shanghai Jiao Tong University Advantages of hydrofluoroalkane (HFA) • Low inhalation toxicity • High chemical stability • High purity • Not ozone depleting Disadvantages of hydrofluoroalkane (HFA) • Poor solvents • Minor greenhouse effect • High cost Shanghai Jiao Tong University Propellants Hydrofluoroalkane (HFA) propellants • Tetrafluoroethane (HFA134a) • Heptafluoropropane (HFA227) Shanghai Jiao Tong University Propellants The pressure of aerosol is critical to its performance. It can be controlled by the type and amount of propellants. Mixture of propellants • Change vapor pressure • Change liquid density • Change solvency