Clear Sunscreen Composition for Wet Skin Application

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional sunscreen products fail to provide effective protection on wet skin, as they tend to dilute, smear, and form an incomplete, unattractive film that peels off, offering poor sun protection.

Innovation Solution

A composition comprising cross-linked copolymers of acrylic acid and a hydrophobic co-monomer, sodium polyacrylate, silicone acrylate, oil, water, and sunscreen actives, which remains clear and stable upon application to wet skin, preventing whitening and ensuring film integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional sunscreen products are applied to wet skin, then the application process is simple, but the sunscreen actives dilute, smear, and form an incomplete film that peels off

Engineering Contradiction:
Improveapplication processVSAvoidfilm integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite polymer system comprising both hydrophobic and hydrophilic polymers that work synergistically to create a film resistant to water while maintaining adhesion to skin. The hydrophobic polymer provides water resistance while the hydrophilic polymer ensures skin adhesion, solving the film integrity problem when applied to wet skin.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the sunscreen formulation by incorporating specific polymer types and ratios, adjusting viscosity, and selecting appropriate solvents to ensure the formulation maintains film integrity on wet skin without diluting or smearing the sunscreen actives.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional sunscreen products are applied to wet skin, then the application is straightforward, but the product takes on a pasty, white appearance

Engineering Contradiction:
Improveapplication simplicityVSAvoidaesthetic appearance
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The patent adjusts formulation parameters including the selection of transparent or translucent polymers, optimization of particle size for any inorganic UV filters, and control of viscosity to prevent pasty appearance. These parameter changes ensure the sunscreen remains aesthetically pleasing when applied to wet skin.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs different polymer components with specific properties in different ratios to achieve uniform clarity and prevent localized whitening or pasty appearance. The hydrophobic and hydrophilic polymers are distributed to ensure consistent optical properties across the film.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If conventional sunscreen products are applied to wet skin, then the application process is simple, but the protection from sun's rays is poor

Engineering Contradiction:
Improveapplication processVSAvoidsun protection effectiveness
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent combines multiple UV-filtering agents including organic UV filters and inorganic UV screens in a composite formulation. This composite approach ensures broad-spectrum sun protection while the polymer system maintains the uniform distribution and stability of these protective agents on wet skin.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent incorporates water-resistant polymers that automatically maintain film integrity and prevent loss of sunscreen actives when exposed to water or sweat, providing self-sustaining protection without requiring reapplication after water exposure.

Inventive Principle:
Principle #25Self-service

4Stability of the object's composition

If a water-in-oil emulsifier is used to self-emulsify in the presence of residual water, then emulsification occurs, but severe aesthetic and performance problems still exist

Engineering Contradiction:
ImproveemulsificationVSAvoidaesthetic and performance quality
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent replaces traditional water-in-oil emulsifiers with a composite polymer system comprising hydrophobic and hydrophilic polymers that provide superior stability without the aesthetic and performance problems of conventional emulsifiers. This composite approach achieves both emulsification and clear appearance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the emulsification mechanism by using polymer-based stabilization rather than traditional surfactants, adjusting the HLB balance through polymer selection to achieve stable emulsion with clear appearance and good performance on wet skin.

Inventive Principle:
Principle #35Parameter changes

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 maintains clarity and stability on wet skin, providing uniform protection and preventing whitening, while ensuring effective sun protection and film integrity.

Implementation Method 1

at least one cross- linked copolymers of acrylic acid and a hydrophobic co-monomer

Methodology Applied
Scientific EffectCross-linking:

Implementation Method 2

cross- linked copolymers of acrylic acid and a hydrophobic co-monomer

Methodology Applied
Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 3

sodium polyacrylate

Methodology Applied
Scientific EffectPolymer film formation:

Implementation Method 4

at least one silicone acrylate

Methodology Applied
Scientific EffectSilicone properties:

Implementation Method 5

conventional sunscreen products generally take the form of ultraviolet (UV)-filter compounds and/or particulate UV-screening compounds (collectively, 'sunscreen actives') that are solublized, emulsified, or dispersed in a vehicle

Methodology Applied
Scientific EffectEmulsification: Emulsion

Implementation Method 6

at least one sunscreen active

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentEP3079779B1Clear sunscreen composition for application onto wet or dry skin
Publication Date: 2020.07.29 LOREAL SA

AI summary

The present invention is directed to a composition containing: at least one cross-linked copolymers of acrylic acid and a hydrophobic co-monomer; at least one polyacrylamide; at least one silicone acrylate; oil; water; and at least one sunscreen active, wherein the composition is initially clear in appearance and remains clear in appearance upon application onto wet skin.