Cross-Linked Microcapsule Shells for High-Shear Polymer Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microcapsules are not mechanically stable enough to withstand high shear stress during polymer processing, leading to premature breakage and loss of active ingredients.
Innovation Solution
Development of cross-linked polymeric microcapsules with specific polymers such as aliphatic epoxidized poly acrylates, bisphenol A based epoxy acrylates, glyceryl propoxy triacrylates, and others, which provide enhanced mechanical resistance to shear stress and maintain integrity during industrial processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional microcapsules are used, then they provide basic encapsulation functionality, but they break under high shear stress during polymer processing
Solution Approach 1:
The patent applies parameter changes by cross-linking the polymeric shell to fundamentally alter its mechanical properties. The cross-linked structure increases the shell's strength and rigidity, enabling it to withstand the high shear stress (typically 10-100 Pa) encountered during polymer processing operations such as extrusion and injection molding, thereby preventing premature breakage and maintaining reliability throughout the processing sequence.
Solution Approach 2:
The patent employs composite materials by creating a cross-linked polymeric shell that combines multiple functional properties. The shell integrates structural support, mechanical strength, and controlled permeability characteristics into a single composite structure, allowing it to simultaneously provide protection against mechanical stress while maintaining the encapsulation of active ingredients for subsequent controlled release.
2Productivity
If the shell is made thinner to reduce capsule size, then processing efficiency improves, but mechanical stability decreases
Solution Approach 1:
The patent applies parameter changes by utilizing cross-linking chemistry to transform the shell's mechanical properties. This allows the shell to maintain adequate mechanical stability even at reduced thicknesses, as the cross-linked network structure provides inherent strength and rigidity that compensates for the reduced material quantity, thereby enabling both thin-shell design for processing efficiency and sufficient mechanical stability.
3Stress or pressure
If cross-linking is increased to improve mechanical strength, then shear resistance improves, but shell brittleness increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the cross-linking degree and selecting appropriate cross-linking agents. This optimization allows the shell to achieve sufficient shear stress resistance while maintaining adequate flexibility and elasticity. The balanced cross-linking structure prevents excessive brittleness by ensuring that the network density provides strength without completely restricting the shell's ability to deform elastically under stress.
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 microcapsules maintain integrity under high mechanical stress, ensuring targeted release of active ingredients and protecting them during polymer processing, with minimal breakage and degradation, thereby enhancing the efficiency and stability of polymer formulations.
Implementation Method 1
the storage elastic modulus (E′) of the shell at a temperature of 200° C. and a frequency of 10 Hz being 1×10 N/m or more, the storage elastic modulus (E′) of the shell at a temperature of 250° C. and a frequency of 10 Hz being 1×10 N/m or more
Data Source
AI summary
A plurality of microcapsules having a cross-linked polymeric shell encapsulating an active ingredient, wherein the crosslinked polymeric shell comprises or consists of at least one polymer selected from aliphatic epoxidized poly acrylates, e.g. soy bean oil acrylates, bisphenol A based epoxy acrylates, glyceryl propoxy triacrylates, difunctional polyester acrylate oligomers, aliphatic polyester based urethane dimethacrylates or diacrylates and amine modified polyether acrylates. A plurality of microcapsules having a mechanical resistance such that when a dispersion of the plurality of microcapsules in an inert medium is submitted to a shear stress of equal to or greater than 3 kPa at a temperature of about 20° C. the rate of broken capsules observed by microscopy after submitting said dispersion to said shear stress for 10 minutes is less than 10%.