PHA Copolymer Film Stability in Humid Cosmetic Media

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Solution Overview

Problem

Existing cosmetic compositions using polyhydroxyalkanoate copolymers do not effectively combine with polysaccharides in fatty media, leading to instability and poor persistence of the film on keratin materials, especially under humid conditions.

Innovation Solution

A cosmetic composition comprising polyhydroxyalkanoate copolymers with specific grafted or functionalized hydrocarbon-based groups, combined with polysaccharides, fatty substances, and optionally surfactants, to create a stable and persistent film on keratin materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polysaccharides are used as film-forming polymers in aqueous phases, then the composition is easy to prepare and apply, but the film lacks resistance to humidity and sweat leading to poor persistence

Engineering Contradiction:

Improveease of preparationVSAvoidpersistence under humid conditions

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent combines polysaccharides (hydrophilic, water-soluble) with polyhydroxyalkanoate copolymers (lipophilic, oil-soluble) to create a composite film-forming system. This composite approach allows the composition to leverage the ease of preparation of polysaccharide-based aqueous systems while gaining the water and sweat resistance of the PHA copolymer matrix, thereby resolving the contradiction between manufacturability and persistence under humid conditions.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention modifies the chemical composition parameters of the film-forming polymer by introducing lipophilic side chains (hydrocarbon-based groups with 6-30 carbon atoms) into the polyhydroxyalkanoate structure. This parameter change transforms the polymer's solubility characteristics, enabling it to form stable films in aqueous phases containing fatty substances while maintaining resistance to water and humidity, thus improving persistence without sacrificing ease of preparation.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If polyhydroxyalkanoate copolymers with lipophilic groups are used in fatty media, then the film has good resistance to oils and sebum, but the composition stability deteriorates over time

Engineering Contradiction:

Improveresistance to oils and sebumVSAvoidcomposition stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the parameters of the polyhydroxyalkanoate copolymer by controlling the length (6-30 carbon atoms) and position of the lipophilic hydrocarbon-based side chains. This parameter optimization enables the polymer to achieve adequate lipophilicity for oil and sebum resistance while maintaining sufficient compatibility with aqueous phases and polysaccharides, thereby preserving composition stability during storage. The balanced parameter selection resolves the contradiction between oil resistance and stability.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If polysaccharides are used alone to form films on keratin materials, then the application is simple, but the film transfers color easily under humid conditions

Engineering Contradiction:

Improveease of applicationVSAvoidcolor transfer

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite film system combining polysaccharides with polyhydroxyalkanoate copolymers featuring lipophilic side chains. The polysaccharide component ensures ease of application through aqueous formulation, while the PHA copolymer component provides a stable, water-resistant matrix that prevents color transfer. This composite structure simultaneously achieves simple application and prevents color transfer under humid conditions by addressing both requirements through material combination.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250127706A1Cosmetic composition comprising a polyhydroxyalkanoate copolymer bearing a(n) (UN)saturated hydrocarbon-based chain and a polysaccharide

Publication Date: 2025.04.24 LOREAL SA

AI summary

The present invention relates to a cosmetic composition comprising a) one or more poly hydroxyalkanoate (PHA) mainfcopolymers comprising at least two different repeating polymer units chosen from the units (A) and (B) below, and also the optical or geometrical isomers thereof, the salts thereof with organic or mineral acids or bases, and the solvates thereof such as hydrates: —[—O—CH(R1)—CH2—C(O)—]— unit (A) —[—O—CH(R2)—CH2—C(O)—]— unit (B) in which polymer units (A) and (B): —R1 and R2 are as defined in the description; and b) one or more polysaccharides: it being understood that: —(A) is different from (B) and the composition contains c) one or more fatty substances and/or e) water.