Method for in-vitro determination of sun protection factor of powder

Abstract

The invention provides a method for in-vitro determination of a sun protection factor (SPF) of a powder. A sun protection factor measurement system SPF-290S is used for determination of the SPF value and the UVAPF value of the powder with the coating weight rated value of 1.2 mg/cm<2>, and respectively measures the SPF values and the UVAPF values of the powder with the coating weights of 0.1 mg/cm<2>, 0.2 mg/cm<2>, 0.3 mg/cm<2>, 0.4 mg/cm<2>, 0.5 mg/cm<2> and 0.6 mg/cm<2>; according to a linear relationship between the SPF values and the powder coating weights and a linear relationship between the UVAPF values and the powder coating weights, the SPF value and the UVAPF value of the powder with the coating weight rated value of 1.2 mg/cm<2>, namely the final SPF value and the final UVAPF value of the powder, are calculated. Therefore, the problem that the SPF-290S cannot measure because the powder with the coating weight of 1.2 mg/cm<2> completely shades light is overcome.

Description

technical field [0001] The invention relates to the measurement of sun protection index, in particular to measuring the sun protection index of powder by using the sun protection index measurement system SPF-290S. Background technique [0002] With the development of cosmetic technology and the improvement of people's demand, in addition to special sunscreen products, major cosmetics manufacturers have begun to add sunscreen ingredients to other categories of cosmetics, including BB cream, CC cream, foundation, pressed powder, lipstick, etc. [0003] At present, the SPF value or UVAPF value of sunscreen products is mainly determined by the method of human body testing, but the SPF value or UVAPF value measured by this method is affected by factors such as the tester's race, skin type, and the length of previous exposure to sunlight. , has great individual differences, and this method will cause harm to the human body. With the maturity of in vitro light transmittance test t...

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Problems solved by technology

[0006] The method for in vitro determination of powder sun protection index provided by the present invention, through a series of effective measurement of powder SPF value and UVAPF value of lower coating amount, uses the SPF value-powder coating amount diagram to fit the powder coating The linear equation between the amount and its SPF value, so that the specified value of the coating amount is calculated to be 1.2mg / cm 2 The SPF value of the powder, use the UVAPF value-powder coating amount diagram to fit the linear equation of the powder coating amount and its UVAPF value, so as to calculate the specified value of the coating amount to be 1.2mg / cm 2 The UVAPF value of the powder, this method overcomes the specified value of coating amount of 1.2mg / cm 2 The complete shading of the powder caused the SPF-290S to make an error and cannot be effectively measured

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