Aqueous Poly(Meth)acrylic Acid Solution Dispersion Stability

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Solution Overview

Problem

Conventional aqueous poly(meth)acrylic acid polymer solutions lack sufficient pigment dispersion ability and stability over time, failing to meet the demands of sophisticated coating techniques.

Innovation Solution

Aqueous poly(meth)acrylic acid (salt) solution is developed using hypophosphorous acid with a small content of phosphorous acid salts, reducing inorganic ions and enhancing dispersion performance and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional poly(meth)acrylic acid polymer solutions are used, then basic detergent builder functions are provided, but pigment dispersion ability and stability over time are insufficient

Engineering Contradiction:
Improvedispersion ability and stabilityVSAvoidpigment dispersion ability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent modifies the molecular weight distribution parameters of the poly(meth)acrylic acid polymer by controlling the polymerization process, specifically achieving a weight average molecular weight of 5,000 to 50,000 and a molecular weight distribution (Mw/Mn) of 1.5 to 3.0. These parameter changes enable the polymer to provide both detergent builder functions and enhanced pigment dispersion ability with improved stability over time.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If polymerization is performed to improve performance, then molecular weight distribution narrows, but inorganic ions from phosphorus compounds increase

Engineering Contradiction:
Improvemolecular weight distributionVSAvoidinorganic ions content
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by using a phosphorus compound with specifically controlled composition (containing hypophosphorous acid and having 0.1 to 10 mass% phosphorous acid) only during the polymerization process to control molecular weight distribution, while ensuring the final polymer product contains less than 2,000 ppm inorganic ions. This localized application of the phosphorus compound achieves the desired molecular weight control without excessive inorganic ion contamination in the final product.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If hypophosphorous acid with high phosphorous acid content is used, then polymerization control is improved, but inorganic ions increase reducing dispersibility

Engineering Contradiction:
Improvepolymerization controlVSAvoiddispersibility
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies partial action by using a phosphorus compound containing hypophosphorous acid with only 0.1 to 10 mass% phosphorous acid content, rather than using high phosphorous acid content compounds. This partial composition provides sufficient polymerization control for achieving narrow molecular weight distribution while minimizing inorganic ion content to less than 2,000 ppm, thereby maintaining high dispersibility of inorganic particles.

Inventive Principle:
Principle #16Partial or excessive action

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 demonstrates high dispersibility and stability of inorganic particles, improving washing performance and maintaining color tone over time when used as a detergent builder or dispersant.

Implementation Method 1

a chain transfer agent is continuously added for a predetermined period during polymerization wherein an addition rate of the chain transfer agent is changed at least once

Methodology Applied
Scientific EffectChain transfer:

Implementation Method 2

Aqueous poly(meth)acrylic acid (salt) solution is developed using hypophosphorous acid with a small content of phosphorous acid salts, reducing inorganic ions and enhancing dispersion performance and stability

Methodology Applied
Scientific EffectSelective polymerization:

Data Source

PatentEP2657261B1Aqueous poly(METH)acrylic acid (SALT) solution and process for preparing same
Publication Date: 2022.06.15 NIPPON SHOKUBAI CO LTD
  • EP2657261B1 patent drawing

AI summary

An object of the present invention is to provide an aqueous poly(meth)acrylic acid (salt) solution having high dispersibility of inorganic substances and demonstrating dispersibility having sufficient stability over time, and a process for preparing the same. The present invention relates to an aqueous poly(meth)acrylic acid (salt) solution comprising a poly(meth)acrylic acid (salt) having a weight average molecular weight of 1000 to 10000 polymerized in the presence of a phosphorus compound containing hypophosphorous acid (salt), wherein the phosphorus compound contains 0 to 0.3% by mass of a phosphorous acid (salt) based on 100% by mass of the phosphorus compound, and the aqueous poly(meth)acrylic acid (salt) solution contains 0 to 10000 ppm of an inorganic anion; and a process for preparing an aqueous poly(meth)acrylic acid (salt) solution comprising the step of polymerizing a monomer in an aqueous solvent in the presence of a phosphorus compound containing hypophosphorous acid (salt), wherein the monomer contains a (meth)acrylic acid (salt) as an essential component, the phosphorus compound contains 0 to 0.3% by mass of a phosphorous acid (salt) based on 100% by mass of the phosphorus compound, the poly(meth)acrylic acid (salt) has a weight average molecular weight of 1000 to 10000, and the aqueous poly(meth)acrylic acid (salt) solution contains 0 to 10000 ppm of an inorganic anion.