1-Hexylpyrazole Hair Dye Composition for Wash Fastness

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Solution Overview

Problem

Existing oxidative hair dye compositions using pyrazole compounds are unsatisfactory in terms of color intensity, wash fastness, and bleeding properties.

Innovation Solution

A composition for oxidative hair dyeing comprising a 1-hexyl/heptyl-4,5-diaminopyrazole compound combined with a 2-aminophenol compound and an oxidizing agent, which modifies the pyrazole ring system with a C6/C7 straight alkyl chain to enhance resistance to hair treatments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional pyrazole compounds are used for oxidative hair dyeing, then the dyeing process can be performed, but the color intensity, wash fastness, and bleeding properties are unsatisfactory

Engineering Contradiction:

Improvewash fastness and bleeding resistanceVSAvoidcolor intensity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent modifies the pyrazole compound structure by changing the alkyl chain length parameter at the N-1 position to C6/C7 straight chain, which optimizes the molecular properties for better hair penetration and coupling efficiency, thereby simultaneously improving both color intensity and wash fastness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite dyeing system by combining the modified 1-hexyl/heptyl-4,5-diaminopyrazole compound with specific 2-aminophenol couplers, where the synergistic interaction between these components produces superior color intensity and fastness properties that neither component achieves alone

Inventive Principle:

Principle #40Composite materials

2Reliability

If the pyrazole ring system is modified with C6/C7 straight alkyl chain, then resistance to hair treatments is enhanced, but the molecular structure becomes more complex

Engineering Contradiction:

Improveresistance to hair treatmentsVSAvoidmolecular structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent systematically varies the alkyl chain length parameter (specifically C6/C7 straight chains) on the pyrazole ring to optimize performance. This targeted parameter modification enhances treatment resistance while maintaining reasonable structural complexity by focusing changes on a specific molecular region rather than redesigning the entire molecule

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 achieves excellent color intensity, wash fastness, and resistance to bleeding, providing improved performance compared to traditional pyrazole-based hair dyes.

Implementation Method 1

oxidative dyeing of keratin fibers... comprising (A) a 1-hexyl/heptyl-4,5-diaminopyrazole compound... (B) a 2-aminophenol compound... and (C) an oxidizing agent

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS8444709B2Oxidative dyeing compositions comprising an 1-hexyl/heptyl-4,5-diaminopyrazole and a 2-aminophenol and derivatives thereof

Publication Date: 2013.05.21 WELLA OPERATIONS US LLC

AI summary

An oxidative dyeing composition comprising a 1-hexyl-4,5-diaminopyrazole compound or a 1-heptyl-4,5-diaminopyrazole compound of formula (I) in combination with a 2-aminophenol compound of formula (II):wherein R1, R2, R3, R4, R5, R6 and R7 are as defined herein and a=1 or 2.The composition provides good hair color intensity together with good wash and bleeding fastness.