Tin-Free Polyurethane Thickeners for High Salt Cosmetics

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Solution Overview

Problem

Existing polyurethane thickeners for aqueous preparations, particularly in cosmetics, face challenges in maintaining thickening effect in high salt concentrations and require the use of tin-based catalysts, which are undesirable in cosmetic applications.

Innovation Solution

A process for preparing polyurethanes with at least three hydrophilic sections, four hydrophobic sections, and optional allophanate or isocyanurate segments, using alkali or alkaline earth metal carboxylates as catalysts, resulting in tin-free, stable, and effective thickeners that maintain viscosity in the presence of salts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tin-based catalysts are used in polyurethane preparation, then the thickening effect is achieved, but the cosmetic safety and environmental friendliness deteriorate

Engineering Contradiction:

Improvethickening effectVSAvoidtin content

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the catalyst type parameter from tin-based compounds to alkali metal carboxylates (such as sodium or potassium carboxylates). This parameter change eliminates toxic tin from the final product while maintaining the polyurethane formation reaction functionality, thus resolving the contradiction between achieving thickening effect and avoiding harmful tin content in cosmetic applications

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs inexpensive alkali metal carboxylates as alternative catalysts that can be easily removed or decomposed, replacing expensive and harmful tin-based catalysts. The alkali metal carboxylate catalysts serve their purpose during synthesis and can be eliminated from the final cosmetic product, addressing both cost and safety concerns

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If polyurethane thickeners are used in high salt concentrations, then the thickening effect is maintained, but the compatibility with other cosmetic ingredients deteriorates

Engineering Contradiction:

Improvethickening effect in high saltVSAvoidcompatibility with salts and surfactants

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates polyurethane molecules with specific local structural characteristics - namely hydrophilic polyether segments combined with hydrophobic fatty alcohol segments in specific ratios. This local structural quality allows the thickener to maintain its thickening function in high salt concentrations while also being compatible with other cosmetic ingredients like salts and surfactants, resolving the contradiction between maintaining thickening effect and achieving broad compatibility

Inventive Principle:

Principle #3Local quality

3Device complexity

If single-step process without catalyst is used, then the process complexity is reduced, but the reaction efficiency and polyurethane quality deteriorate

Engineering Contradiction:

Improveprocess stepsVSAvoidreaction efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent changes the catalyst parameter to alkali metal carboxylates, which are highly effective catalysts for polyurethane formation. This parameter change enables the single-step process to proceed with high reaction efficiency and produce high-quality polyurethane thickeners, thus resolving the contradiction between process simplicity and reaction efficiency

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 solution provides polyurethane thickeners that maintain excellent thickening properties in high salt concentrations without using tin, ensuring stability and effectiveness in cosmetic applications while being environmentally friendly and cost-effective.

Implementation Method 1

using alkali or alkaline earth metal carboxylates as catalysts

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

the hydrophobic segments construct a viscosity-imparting three-dimensional molecular association via an association with one another and also with dispersed binder particles

Methodology Applied

Scientific EffectAssociation:

Data Source

PatentUS9175125B2Polyurethane thickeners

Publication Date: 2015.11.03 BASF SE

AI summary

The present invention relates to a process for preparing polyurethanes, which comprise at least three hydrophilic sections, at least four hydrophobic sections, optionally allophanate segments and/or isocyanurate segments and which are prepared in the presence of alkali(ne earth) metal carboxylates. The process may comprise using at least one carboxylic acid salt of at least one metal selected from the group consisting of the alkali metals, the alkaline earth metals and mixtures thereof Furthermore, the present invention relates to the polyurethanes per se obtainable in this way, to the use thereof as thickeners for aqueous preparations, and to preparations comprising polyurethanes of this type.