Polyurethane Organopolysiloxane Finishes With pH-Stable Emulsification

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Solution Overview

Problem

Polysiloxanes containing amino groups face challenges with pH sensitivity, leading to precipitation and phase separation at higher pH values, and are destabilized by anionic substances, resulting in silicone stains and poor emulsification stability during textile finishing processes.

Innovation Solution

The development of polyurethane organopolysiloxanes with pendant polyether groups, produced by reacting hydroxy-modified organopolysiloxanes with di- or polyisocyanates, which exhibit excellent soft-touch effects, pH stability, and resistance to anionic substances, allowing for self-emulsification in aqueous media with minimal surfactant use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If amino-functional polysiloxanes are used as textile finishing agents, then good soft-touch effects are achieved, but the preparations become sensitive to pH fluctuations causing precipitation and phase separation at higher pH values

Engineering Contradiction:

Improvesoft-touch effectVSAvoidpH stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention changes the chemical parameter of the functional group from amino to quaternary ammonium, which fundamentally alters the pH dependence. Quaternary ammonium groups remain cationic across the entire pH range, eliminating the precipitation problem that occurs with amino groups at high pH while maintaining the soft-touch finishing effect on textiles

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure by combining organopolysiloxane with quaternary ammonium groups and optionally polyether radicals. This composite approach allows the material to simultaneously exhibit pH stability from the quaternary ammonium groups and desired textile finishing properties from the polysiloxane backbone, resolving the contradiction between soft-touch effect and pH stability

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If amino or ammonium groups are used in polysiloxanes, then emulsification is improved, but the preparations become sensitive to anionic substances leading to salt formation and emulsion destabilization

Engineering Contradiction:

ImproveemulsificationVSAvoidanion stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the charge interaction parameter by using quaternary ammonium groups that maintain permanent cationic character. This allows the polysiloxane to remain effective in the presence of anionic substances without forming destabilizing salts, while still achieving good emulsification in aqueous media through the cationic-natural fiber interaction

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The quaternary ammonium groups act as intermediaries that bridge the polysiloxane and aqueous medium without being blocked by anionic substances. The permanent positive charge allows continuous interaction with anionic surfactants and other anionic agents without forming insoluble salts, maintaining emulsion stability throughout the textile processing sequence

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If quaternary ammonium groups are used instead of amino groups, then pH stability is improved, but the complexity of the chemical structure increases

Engineering Contradiction:

ImprovepH stabilityVSAvoidchemical structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the chemical parameter from simple amino groups to quaternary ammonium groups, accepting increased structural complexity in exchange for dramatically improved pH stability. The quaternary ammonium structure, while more complex, provides permanent cationic character that ensures reliability across the entire pH range encountered in textile processing

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If amino groups are protonated by adding acid to improve emulsifiability, then emulsion stability is improved, but the sensitivity to pH fluctuations increases

Engineering Contradiction:

ImproveemulsifiabilityVSAvoidpH sensitivity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The quaternary ammonium groups are self-service in that they automatically maintain their cationic character and emulsifying capability across all pH ranges without requiring external acid addition. The permanent positive charge is inherent to the quaternary ammonium structure, eliminating the need for pH adjustment and the associated sensitivity to pH fluctuations

Inventive Principle:

Principle #25Self-service

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

These polyurethane organopolysiloxanes provide stable and effective soft-touch finishes on textiles with improved pH and anion stability, reduced foam development, and enhanced hydrophilicity, minimizing silicone stains and ensuring consistent application.

Implementation Method 1

The polyurethane organopolysiloxanes according to the invention can be emulsified in an aqueous medium without or with only small amounts of additional surfactants

Methodology Applied

Scientific EffectSelf-emulsification: Emulsion