Amino Acid Pretreatment for Keratin Fiber Dyeing

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Solution Overview

Problem

Hair dyeing and bleaching processes often result in unsatisfactory color build-up, intensity, and uniformity, especially on hair sensitized by repeated chemical treatments or laden with metals like copper, due to the negative impact of metal accumulation.

Innovation Solution

The use of specific amino acids, such as glycine, as a pretreatment for keratin fibers to improve dyeing or bleaching performance by enhancing color build-up and intensity and achieving better color uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dyeing or bleaching compositions are applied to hair, then the hair can be dyed or bleached, but the dyeing or bleaching performance is unsatisfactory when hair is sensitized by repeated chemical treatments or laden with metals

Engineering Contradiction:

Improvedyeing or bleaching performanceVSAvoidimpact of metal accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The amino acid composition is applied as a pretreatment before the dyeing or bleaching process. This preliminary action modifies the hair surface and removes metal ions in advance, creating optimal conditions for subsequent dyeing or bleaching operations, thereby ensuring reliable performance even on previously treated hair

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The amino acids in the composition bind to and remove harmful metal ions (such as copper) from the hair surface. By converting the harmful metal accumulation into a removable complex, the pretreatment eliminates the negative impact of metals on dyeing or bleaching performance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If hair undergoes repeated chemical treatments, then hair styling and color changes are achieved, but color build-up, intensity, and uniformity deteriorate

Engineering Contradiction:

Improvehair treatment flexibilityVSAvoidcolor uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The amino acid pretreatment is applied before each dyeing operation to restore the hair surface to an optimal state. This preliminary conditioning ensures that each subsequent dyeing treatment achieves consistent color build-up and uniformity, regardless of the hair's treatment history

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The amino acid composition modifies the chemical and physical parameters of the hair surface, including surface charge, hydrophobicity, and metal ion content. These parameter changes create a standardized substrate that responds predictably to dyeing treatments, ensuring color uniformity across repeatedly treated hair

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 pretreatment with amino acids improves color build-up and intensity, reducing color differences and achieving uniformity on hair enriched with copper, comparable to untreated hair, thereby enhancing the overall dyeing or bleaching performance.

Implementation Method 1

The applicant has discovered, surprisingly, that all of these objectives can be achieved by means of the uses according to the present invention

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

when the hair is laden with metals such as copper which, by accumulating on the hair over the course of successive washing operations

Methodology Applied

Scientific EffectChelation:

Data Source

PatentUS20230381080A1Use of particular amino acids as a pretreatment for a process for dyeing or bleaching keratin fibres

Publication Date: 2023.11.30 LOREAL SA

AI summary

The present invention relates to the use of one or more particular amino acids or of a composition comprising same as a pretreatment for a process for dyeing or bleaching keratin fibres in order to improve the dyeing or bleaching of the keratin fibres.