Polyurethane and Cross-linked Starch Film for Skin Protection
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Solution Overview
Problem
Conventional cosmetic compositions fail to effectively prevent or reduce the deposition of fine particles from polluted air on the skin and scalp, leading to potential skin problems such as clogged pores and discomfort.
Innovation Solution
A cosmetic composition comprising an aqueous cosmetically acceptable medium with 6% to 50% by weight of aqueous polyurethane dispersion and 2% to 8% by weight of cross-linked starch, which forms a breathable, non-tacky, and moderate waterproof film on the skin that can be easily peeled off, providing protection from polluted air while enhancing water resistance and skin affinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a film-forming composition is applied to protect skin from pollutants, then protection effectiveness is improved, but the film may be difficult to remove
Solution Approach 1:
The patent changes the chemical parameters of the film-forming composition by incorporating specific cross-linked starch derivatives with controlled degrees of substitution and cross-linking. This modifies the film's adhesive properties to achieve optimal balance between protection effectiveness and ease of removal, allowing the film to adhere sufficiently for protection while remaining removable without excessive force
Solution Approach 2:
The patent creates a composite film system combining polyurethane polymers with cross-linked starch derivatives. This composite structure integrates the protective barrier properties of polyurethane with the controlled adhesion characteristics of cross-linked starch, achieving both effective pollution protection and manageable removal properties
2Duration of action of stationary object
If the film is made waterproof and long-wearing, then durability is improved, but breathability may be reduced
Solution Approach 1:
The patent utilizes cross-linked starch derivatives that form a semi-permeable network structure within the film. This porous-like structure allows selective permeability to water vapor and breathable gases while maintaining resistance to liquid water penetration, thus achieving both long-wearing durability and skin breathability
Solution Approach 2:
The patent optimizes the degree of cross-linking and substitution parameters of the starch derivative to control the film's permeability characteristics. By adjusting these parameters, the film achieves appropriate balance between water resistance for durability and vapor permeability for breathability
3Reliability
If the film has strong adhesion to skin, then protection effectiveness is improved, but the film becomes tacky and uncomfortable
Solution Approach 1:
The patent modifies the adhesion parameters by controlling the degree of cross-linking and substitution in the starch derivative. This creates an optimal adhesion strength that provides sufficient protection effectiveness while eliminating excessive tackiness and discomfort during wear
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
The composition effectively forms a long-wearing, flexible film that protects the skin from pollutants, is easy to remove, and offers skin care benefits with active agents, improving skin health and reducing the adverse effects of air pollution.
Implementation Method 1
the combination of cross-linked starch with polyurethane enhances the water resistance of the polyurethane film
Implementation Method 2
it could be moldable on skin, and quickly forms an invisible/visible film after 1-2 minutes of drying time
Data Source
AI summary
A cosmetic composition comprising, in an aqueous cosmetically acceptable medium: a) from 6% to 50% by weight in active material of at least one aqueous polyurethane dispersion; and b) from 2% to 8% by weight of at least one cross-linked starch, the weight being expressed by weight of the total weight of the composition.