Chloride-Free Mixed-Charge Polymers for Detergents

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Solution Overview

Problem

The preparation of mixed-charge polymers for detergent formulations is hindered by the corrosive nature of chloride ions, which require expensive, chloride-resistant reactors and can lead to metal corrosion in dishwashers, necessitating the development of chloride-free alternatives.

Innovation Solution

Mixed-charge polymers are synthesized using monomeric cations and anions as counterions in the absence of chloride or halide ions, allowing for the formation of chloride-free polymers suitable for laundry and automatic dishwashing detergents, with specific structures and compositions that include multiple pendant quaternary ammonium and carboxylate functionalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mixed-charge polymers are prepared using conventional polymerization with monomeric cationic chloride salt, then the polymerization process can proceed effectively, but chloride ions are introduced that cause corrosion to metal reactors and metal components in dishwashers

Engineering Contradiction:

Improvepolymerization process effectivenessVSAvoidmetal corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes the harmful chloride counterion from the polymerization process by using non-chloride alternative counterions (such as acetate, propionate, or other carboxylate ions). This allows the polymerization to proceed effectively while eliminating the corrosive chloride ions that damage metal reactors and dishwasher components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical parameter of the counterion from chloride to non-chloride alternatives (acetate, propionate, carboxylates). This parameter change maintains the electrical neutrality and functionality of the mixed-charge polymer while eliminating the corrosive properties associated with chloride ions.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If chloride-resistant reactors or special alloy reactors are used to prevent corrosion, then metal corrosion is prevented, but the cost of reactor equipment increases significantly

Engineering Contradiction:

Improvemetal corrosion protectionVSAvoidreactor cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention removes the source of the problem (chloride ions) from the polymerization process, thereby eliminating the need for expensive chloride-resistant reactors or special alloy materials. Standard steel reactors can be used without degradation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention enables the use of cheaper, standard steel reactors instead of expensive chloride-resistant materials. By eliminating chloride from the process, the reactor becomes a less critical, more replaceable component that does not require special corrosion-resistant properties.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If mixed-charge polymers containing chloride ions are used in detergent formulations, then the polymers can be effectively synthesized, but the chloride ions corrode and degrade metal components inside the dishwasher

Engineering Contradiction:

Improvepolymer synthesis feasibilityVSAvoiddishwasher component degradation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention changes the counterion parameter from chloride to non-chloride alternatives in the final polymer product. This maintains the synthesizability and effectiveness of the mixed-charge polymer while eliminating the harmful chloride ions that would otherwise degrade dishwasher metal components.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts a potentially harmful situation (need for effective polymer synthesis) into a beneficial outcome by choosing alternative counterions that enable both effective synthesis and protection of dishwasher components from corrosion.

Inventive Principle:

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

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 resulting chloride-free mixed-charge polymers are effective in detergent formulations, reducing spotting on dishes and inhibiting soil redeposition without contributing to metal corrosion, and can be produced using less expensive reactor materials.

Implementation Method 1

Preparing mixed-charge polymers typically requires polymerization of a monomeric cationic chloride salt with an anionic monomer or monomers that are converted to anions after polymerization with the monomeric cationic chloride salt

Methodology Applied

Scientific EffectPolymerization:

Data Source

PatentUS11118142B2Detergent formulation containing mixed-charge polymers and nonionic surfactant

Publication Date: 2021.09.14 UNION CARBIDE CORP

AI summary

A detergent formulation comprises 0.5 to 10 weight-percent mixed-charge polymer and one to 10 weight-percent nonionic surfactant, where weight-percent is relative to total detergent formulation weight, and wherein the mixed-charge polymer comprises quaternary ammonium groups and carboxylate groups extending as pendant side groups from the polymer backbone.