Dynamic Contact Angle Substrate for Uniform Cosmetic Coating
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Solution Overview
Problem
Current methods for evaluating UV protection in cosmetics require multiple substrates with different contact angles, leading to inefficiencies and inaccuracies in SPF measurement due to phase separation and non-uniform coating issues, making them unsuitable as a substitute for in-vivo methods.
Innovation Solution
A substrate with a UV-transmitting base material and a hydrophilic layer containing compounds with a sugar skeleton but not a salt, which changes contact angle over time, allowing for uniform coating and precise SPF measurement using a single substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple substrates with different contact angles are used to measure UV protection, then measurement precision is improved, but device complexity and time consumption increase significantly
Solution Approach 1:
The substrate surface properties are made dynamic by using a contact angle modifier that changes the contact angle over time. This allows a single substrate to provide different surface conditions at different measurement time points, eliminating the need for multiple substrates with fixed different contact angles while maintaining measurement precision for various cosmetic formulations.
Solution Approach 2:
The contact angle parameter of the substrate surface is changed dynamically through the action of the contact angle modifier. By controlling the time elapsed since application of the modifier, the substrate can present different contact angle values (e.g., 30°, 40°, 50°) without requiring multiple physical substrates, thus reducing device complexity while preserving measurement accuracy.
2Measurement precision
If multiple substrates with different contact angles are prepared beforehand, then measurement precision is improved, but loss of time increases considerably
Solution Approach 1:
The contact angle modifier is applied to the substrate in advance, and its effect is allowed to develop over time before measurement. This preliminary action creates a dynamic surface property that can be adjusted by controlling elapsed time, eliminating the need to prepare and store multiple substrates with different contact angles beforehand, thus significantly reducing preparation time.
Solution Approach 2:
Instead of having static substrates with fixed different contact angles that must be prepared and selected in advance, the system uses a single substrate with a dynamic surface property that evolves over time. The contact angle changes from an initial value to a final value as time passes, providing flexibility without time-consuming preparation of multiple substrates.
3Ease of operation
If substrates with fixed contact angles are used, then ease of operation is improved, but measurement precision deteriorates due to phase separation and non-uniform coating
Solution Approach 1:
The substrate surface dynamically adjusts its contact angle over time, allowing it to adapt to different cosmetic formulations. This dynamic adjustment prevents phase separation and non-uniform coating by providing the optimal surface tension at the moment of application, while still being simple to operate as a single substrate system rather than selecting from multiple fixed substrates.
Solution Approach 2:
The contact angle parameter changes over time, allowing the substrate to provide optimal surface properties for coating uniformity. By controlling the elapsed time since contact angle modifier application, the system achieves precise measurement results while maintaining ease of operation with a single substrate type.
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
Enables accurate and efficient SPF measurement for various cosmetic preparations by ensuring a uniform coating film, reducing the need for multiple substrates and improving measurement precision.
Implementation Method 1
a layer provided on one side thereof that contains at least one type of compound other than cellulose triacetate that has a sugar skeleton but is not a salt... whose contact angle with distilled water 5 minutes after it was dripped onto the layer... is different by 15 degrees or more from the contact angle immediately after dripping
Data Source
AI summary
An object is to develop a measurement method, and a measurement substrate, for measuring SPF or other value in a single measurement, instead of having to measure it on many substrates as has been the case to date. As a solution, a substrate for UV transmittance evaluation, including a base material that allows UV rays in a range of 290 to 400 nm to transmit through, and a layer provided on one side thereof that contains at least one type of compound other than cellulose triacetate that has a sugar skeleton but is not a salt, is provided.