Core-Shell Coating Composition for Stain Resistance

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Solution Overview

Problem

Existing compositions for coating substrates to prevent soil and stain accumulation often face challenges such as environmental concerns due to volatile organic solvents, complex application processes, and inadequate shelf-life, while also requiring a tradeoff between performance, environmental friendliness, and ease of use.

Innovation Solution

A composition comprising an aqueous continuous liquid phase with core-shell particles, where a polymer core is surrounded by nonporous spherical silica particles, and a pH value of less than 5, which provides long-lasting protection from staining minerals and soap deposits without volatile organic solvents and is easy to apply, with a method involving the combination of alkaline dispersions and acidification to create the core-shell particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If volatile organic solvents are used in coating compositions, then the composition can provide protective layers with desirable properties, but environmental issues arise

Engineering Contradiction:
Improveprotective layer performanceVSAvoidenvironmental issues
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing volatile organic solvents with water as the continuous liquid phase, and adjusting the pH to less than 5 to stabilize the core-shell particles. This parameter change eliminates environmental harm while maintaining protective layer performance through the engineered core-shell structure of polymer cores with silica shells.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If complex application processes are used, then desired performance attributes can be achieved, but ease of use by unskilled users deteriorates

Engineering Contradiction:
Improveperformance attributesVSAvoidease of use
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The composition is formulated to be self-stabilizing at low pH, eliminating the need for complex application procedures. The core-shell structure and acidic pH condition prevent particle aggregation and maintain stability during storage and application, allowing unskilled users to apply the coating without specialized knowledge or equipment.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If compositions are formulated for long shelf-life, then stability is improved, but performance attributes may be compromised

Engineering Contradiction:
Improveshelf-lifeVSAvoidperformance attributes
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent uses parameter changes by maintaining the composition at a pH of less than 5, which stabilizes the core-shell particle structure during storage. The acidic environment prevents particle aggregation and degradation, ensuring both long shelf-life and consistent performance attributes when applied. The low pH is maintained throughout storage and application.

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If environmentally friendly materials are used, then environmental friendliness is improved, but satisfactory shelf-life deteriorates

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidshelf-life
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent uses composite materials by creating core-shell particles with polymer cores and silica shells, dispersed in an aqueous continuous phase at low pH. This composite structure provides environmental friendliness through water-based formulation while the acidic pH and core-shell architecture ensure long shelf-life by preventing particle aggregation and degradation.

Inventive Principle:
Principle #40Composite materials

5Reliability

If core-shell particles with nonporous spherical silica are used, then protection from staining minerals and soap deposits is improved, but formulation complexity increases

Engineering Contradiction:
Improveprotection from stains and depositsVSAvoidformulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses parameter changes by controlling the pH at less than 5 and using nonporous spherical silica particles with specific size ranges (60 nm or less). These parameter specifications simplify the formulation approach while achieving superior protection from stains and deposits through the engineered core-shell structure and acidic stabilization.

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 offers extended shelf stability, easy application, and effective protection against stains and soap deposits on hard surfaces, such as bathroom fixtures and windows, while being environmentally friendly and suitable for use by unskilled users.

Implementation Method 1

core-shell particles, each core-shell particle comprising a polymer core surrounded by a shell consisting essentially of nonporous spherical silica particles disposed on the polymer core

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

gradually acidifying the alkaline dispersion such that a major portion of the polymer particles are converted to core-shell particles

Methodology Applied
Scientific EffectAcidification:

Data Source

PatentEP2414455B1Coating composition and method of making and using the same
Publication Date: 2014.02.26 3M INNOVATIVE PROPERTIES CO
  • EP2414455B1 patent drawingFigure 1~2

AI summary

Compositions include an aqueous continuous liquid phase and core-shell particles dispersed in the aqueous continuous liquid phase. Each core-shell particle includes a polymer core surrounded by a shell consisting essentially of nonporous spherical silica particles disposed on the polymer core, wherein the nonporous spherical silica particles have a volume average particle diameter of 60 nanometers or less. Methods of making and using the compositions to coat a substrate are also disclosed.