Isothiazolone Formulation Stability via Copper Complexing
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Solution Overview
Problem
Existing microbicidal compositions containing 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) lack stability when stored at elevated temperatures, leading to color changes and precipitation issues.
Innovation Solution
A method involving the combination of a glycol solvent, dodecylbenzenesulfonic acid, and a copper(II) salt, with controlled heating to stabilize copper ions, followed by the addition of DCOIT and removal of excess insoluble copper salts, to create a stable microbicidal composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a microbicidal composition containing DCOIT is prepared using conventional methods, then the composition provides microbial inhibition, but the composition exhibits color instability and precipitation when stored at elevated temperatures
Solution Approach 1:
The patent changes the chemical parameters by introducing a copper complexing agent (such as EDTA, HEDTA, or NTA) in specific amounts (0.01-5% by weight) to form stable copper complexes. This parameter change prevents copper-induced degradation and maintains color stability at elevated temperatures without affecting the microbicidal activity of DCOIT
Solution Approach 2:
The copper complexing agent acts as an intermediary substance that mediates between the copper ions (which can cause instability) and the DCOIT active ingredient. The complexing agent binds copper ions to form stable complexes, preventing them from catalyzing degradation reactions that would lead to color changes and precipitation
2Reliability
If the composition is formulated to enhance microbial inhibition, then the microbicidal activity is improved, but the stability at elevated temperatures deteriorates
Solution Approach 1:
The patent creates a composite formulation by combining DCOIT with copper complexing agents in specific ratios. This composite approach allows the composition to maintain both microbicidal effectiveness (from DCOIT) and thermal stability (from the copper complex), resolving the contradiction between activity and stability
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 method results in a stable microbicidal composition that maintains color stability and prevents precipitation upon storage at elevated temperatures, ensuring effective microbial inhibition and prolonged shelf life.
Implementation Method 1
combining a glycol solvent, dodecylbenzenesulfonic acid, and a copper(II) salt, with controlled heating to stabilize copper ions
Implementation Method 2
controlled heating to stabilize copper ions
Implementation Method 3
Excess insoluble copper(II) hydroxide or oxide salts are removed from the final mixture. Preferably copper(II) salts are removed by filtration or centrifugation
Implementation Method 4
Excess insoluble copper(II) hydroxide or oxide salts are removed from the final mixture. Preferably copper(II) salts are removed by filtration or centrifugation
Data Source
AI summary
A method for producing a stable microbicidal composition. The method comprises steps of: (a) combining a glycol solvent of formula R (OCH2CHR1) nOH, wherein R is C1-C6 alkyl and n has a number average value from 2 to 5 and R1 is hydrogen or methyl; dodecylbenzenesulfonic acid in an amount from 0.3 to 1.8 wt％based on the entire microbicidal composition; and a copper (II) salt selected from the group consisting of copper (II) hydroxide, copper (II) carbonate and mixtures thereof to form an initial mixture; wherein a mole ratio of copper: dodecylbenzenesulfonic acid is from 1:0.25 to 1:1.95; (b) maintaining the initial mixture at 40 to 80℃until an amount of copper ion in solution is stable; and (c) adding 4, 5-dichloro-2-n-octyl-4-isothiazolin-3-one to produce a final mixture.