Sunscreen UV Protection Evaluation Under Heat Stress
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Solution Overview
Problem
Existing methods for evaluating the ultraviolet (UV) protective effects of sunscreen products do not account for the influence of heat, which can affect the performance of UV absorbers and scattering agents, leading to potential deterioration of protective effects.
Innovation Solution
An evaluation method that involves forming a coating film of the sunscreen on a base body, subjecting it to heat treatment in a UV-shielded environment, and measuring the UV protective effect before and after heating to assess the impact of heat on the sunscreen's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional UV protective effect evaluation methods are used, then the evaluation is simple and quick, but the influence of heat on UV protective effect is not accounted for
Solution Approach 1:
The patent applies preliminary action by performing heat treatment on the sunscreen coating film before measuring UV protective effect. This allows the evaluation to account for heat-induced changes in UV absorber and scattering agent performance, thereby improving measurement precision without significantly increasing overall method complexity
Solution Approach 2:
The evaluation method is segmented into distinct steps: (1) applying sunscreen to form a coating film, (2) subjecting the film to heat treatment, and (3) measuring UV protective effect. This segmentation allows each step to be optimized independently while maintaining overall simplicity
2Measurement precision
If heat treatment is incorporated to evaluate UV protective effect under heat influence, then the evaluation accuracy improves, but the evaluation time increases
Solution Approach 1:
Heat treatment is performed as a preliminary step before UV protective effect measurement, allowing the system to reach thermal equilibrium and simulate real-world conditions. This preliminary action ensures accurate evaluation of heat influence while maintaining efficient timing by not requiring separate heating and cooling cycles
Solution Approach 2:
The patent controls heat treatment parameters (temperature, duration) to match typical usage conditions, allowing evaluation of UV protective effect under realistic heat stress. By optimizing these parameters, the method achieves high measurement precision without excessive time consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for the appropriate evaluation of heat's influence on the UV protective effect of sunscreens, enabling the identification of products whose protective effects may improve or deteriorate with temperature changes.
Implementation Method 1
by virtue of the action of an ultraviolet (UV) absorber or an ultraviolet (UV) scattering agent blended in the cosmetics
Implementation Method 2
by virtue of the action of an ultraviolet (UV) absorber or an ultraviolet (UV) scattering agent blended in the cosmetics
Data Source
Figure 1
Figure 2(A)~2(C)
Figure 3
AI summary
The purpose of the present invention is to newly provide a method with which it is possible to appropriately evaluate the protective effect of an external preparation for skin such as a sunscreen cosmetic, particularly to evaluate how a UV-ray protective effect is affected by heat. This evaluation method is characterized by including (1) a step for forming a coating film of an external preparation for skin on a substrate, (2) a step for heat-treating the coating film of the external preparation for skin, and (3) a step for measuring the UV-ray protective effect of the heat-treated coating film of the external preparation for skin. The heat treatment is preferably carried out for at least one minute at a temperature of 30-70°C. The step for measuring the UV-ray protective effect preferably includes at least one selected from testing methods that involve comparing some kind of UV-ray protective effect with SPF measurement, UVAPF or PFA measurement, critical wavelength measurement, absorbance measurement, and transmittance measurement. This evaluation method can also be performed in vivo or in vitro.