Low-Melting Biocidal Formulation for Coating Stability

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Solution Overview

Problem

Existing biocidal compositions for coatings face challenges such as rapid leaching of low-water-solubility active ingredients, particle size variability affecting microbiological efficacy, and exposure risks in handling powders, along with limitations in concentration and VOC emissions in solvent-based solutions.

Innovation Solution

A stable low-melting biocidal composition comprising 50-70% 4,5-dichloro-2-octyl-3(2H)-isothiazolone, 20-30% 3-iodopropargyl-N-butyl carbamate, and 5-30% C1-C4 alkyl 4-hydroxybenzoate, formulated as an aqueous dispersion with surfactants, fillers, and thickeners to minimize VOC and enhance distribution and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If powder form biocides are used to protect coatings, then low water solubility prevents rapid leaching, but handling involves significant toxic dust exposure risk and particle size variation limits microbiological efficacy

Engineering Contradiction:
Improveprotection against leachingVSAvoidtoxic dust exposure and particle size variation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the biocidal composition from solid powder to liquid form (aqueous dispersion). This is achieved by formulating the biocides in a liquid carrier system, eliminating dust generation during handling while maintaining the low water solubility characteristic that prevents rapid leaching from coatings.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses an aqueous dispersion system (liquid phase) to replace solid powder handling. The biocidal ingredients are dispersed in water with appropriate surfactants and thickeners to create a stable liquid formulation, which eliminates aerosolization and dust exposure risks associated with powder application.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Object-affected harmful factors

If concentrated solutions in organic solvents are prepared, then handling safety is improved, but concentration is limited and considerable VOC is introduced into the environment

Engineering Contradiction:
Improvehandling safetyVSAvoidVOC emissions
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent changes the solvent system parameter from organic solvents to water-based aqueous dispersion. This substitution eliminates VOC emissions while maintaining the ability to formulate concentrated biocidal compositions. The liquid state allows for high concentration without the limitations of organic solvent solubility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive organic solvent systems with a water-based system that is environmentally benign. Water serves as the carrier medium, eliminating the need for volatile organic compounds while achieving the same functional purpose of dissolving and distributing the biocidal ingredients.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Quantity of substance

If flowable aqueous dispersions are used, then concentration is improved and VOC is reduced, but stable low-melting mixtures containing specific biocides have not been achieved

Engineering Contradiction:
ImproveconcentrationVSAvoidstability of low-melting mixture
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent creates a composite aqueous dispersion system combining multiple components: biocidal ingredients (IPBC and DCOIT), water, surfactants, and thickeners. This composite formulation achieves both high concentration and stability by synergistically combining materials that address each other's limitations - the surfactants prevent precipitation while the thickeners maintain suspension stability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces surfactants as intermediary substances that mediate between the hydrophobic biocidal ingredients and the aqueous environment. These surfactants form micelles or emulsions that solubilize the biocides in water, enabling high concentration stable dispersions. Thickeners serve as additional intermediaries to maintain physical stability and prevent settling.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a stable, concentrated, and evenly distributed biocidal effect with reduced particle size and VOC emissions, enhancing microbiological efficacy and safety in handling, while maintaining low melting points and stability against crystallization and agglomeration.

Implementation Method 1

low-melting mixtures of phenolic biocides which can be used to make aqueous dispersions

Methodology Applied
Scientific EffectFreezing point depression: Melting

Implementation Method 2

from 10% to 20% of a combination of surfactants, fillers and thickeners

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Implementation Method 3

stability against crystallization and agglomeration

Methodology Applied
Scientific EffectCrystallization prevention: Melting

Data Source

PatentEP2108259B1Low-melting biocidal formulation
Publication Date: 2010.12.22 ROHM & HAAS CO

AI summary

A low-melting biocidal composition comprising 4,5-dichloro-2-octyl-3(2H)-isothiazolone, 3-iodopropargyl-N-butyl carbamate and at least one C1-C4 alkyl 4-hydroxybenzoate. The composition is stable with regard to agglomeration and crystallization at room temperature.