Sulfonamide Herbicide Paste Extrusion Buffering

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Solution Overview

Problem

Current sulfonamide herbicide formulations face challenges in achieving effective water dispersibility and spray equipment clean-out, particularly when using the free acid form, which can result in residue buildup and complex clean-out procedures.

Innovation Solution

A process for preparing paste-extruded sulfonamide herbicide compositions that include at least 50 equivalent % of an inorganic base with a conjugate acid pKa greater than the sulfonamide herbicide free acid, enhancing both water dispersibility and spray equipment clean-out properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfonamide herbicide free acid is used in formulation, then herbicidal efficacy is maintained, but spray equipment residue buildup increases and clean-out becomes difficult

Engineering Contradiction:

Improveherbicidal efficacyVSAvoidspray equipment clean-out

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces a buffering system comprising a water-soluble base and its conjugate acid as an intermediary between the sulfonamide herbicide free acid and the spray equipment. This buffer system controls the pH to prevent excessive residue buildup while maintaining herbicidal efficacy, thereby facilitating easier clean-out of spray equipment without compromising the active ingredient's effectiveness

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the pH parameter of the formulation by adding a buffering system. By controlling the pH within a specific range (pH 5.0-9.0, preferably pH 6.0-8.0), the formulation reduces residue buildup on spray equipment while maintaining the herbicidal activity of the sulfonamide free acid, thus resolving the contradiction between efficacy and ease of clean-out

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If paste extrusion process is used, then granule consistency and shape are improved, but water dispersibility may be compromised without adequate disintegration aids

Engineering Contradiction:

Improvegranule consistencyVSAvoidwater dispersibility

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent creates a composite granule structure combining sulfonamide herbicide free acid, buffering agents (water-soluble base and conjugate acid), and disintegration aids. This composite formulation maintains the consistency benefits of paste extrusion while the disintegration aids embedded in the matrix ensure rapid water dispersibility, resolving the contradiction between manufacturing precision and ease of manufacture

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by incorporating disintegration aids specifically within the granule matrix during paste extrusion. These aids are distributed throughout the granule structure, creating localized weak points that facilitate rapid disintegration upon contact with water, thereby maintaining both granule consistency and water dispersibility

Inventive Principle:

Principle #3Local quality

3Device complexity

If water is used as plasticizer in paste extrusion, then formulation simplicity is maintained, but gas-generating disintegration ingredients cannot be included

Engineering Contradiction:

Improveformulation simplicityVSAvoiddisintegration acceleration

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical nature of the disintegration mechanism by using pH-modifying agents instead of gas-generating ingredients. The buffering system creates localized pH changes that weaken the granule matrix structure, enabling disintegration without requiring carbonates or other gas-generating materials, thus maintaining formulation simplicity while achieving effective disintegration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical disintegration mechanism (gas generation from carbonates reacting with water) with a chemical mechanism (pH-mediated matrix weakening). This substitution allows the use of water as the sole liquid plasticizer while still achieving rapid granule disintegration through pH-controlled matrix degradation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 process results in sulfonamide herbicide compositions with improved dispersibility and significantly reduced residues in spray equipment, facilitating easier clean-out and enhanced weed control efficacy.

Implementation Method 1

paste extrusion using water to plasticize a powder mixture

Methodology Applied

Scientific EffectPlasticization: Plasticity

Implementation Method 2

drying after extrusion

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS8071508B2Process for preparing paste-extruded sulfonamide compositions

Publication Date: 2011.12.06 FMC CORP

AI summary

Paste-extruded sulfonamide herbicide compositions having improved spray equipment clean-out properties are made by preparing a mixture comprising a sulfonamide herbicide free acid, at least about 50 equivalent % of an inorganic base relative to the sulfonamide herbicide free acid and sufficient water to form an extrudable past, extruding the mixture to form an extrudate, and drying the extrudate.