Aminoplast Microcapsule Shell Stability via Diamine Cross-linking
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Solution Overview
Problem
Existing encapsulated perfume compositions using melamine-formaldehyde microcapsules often suffer from discoloration issues when resorcinol is used in their preparation, which affects their stability and performance.
Innovation Solution
Replacing resorcinol with a diamine as a cross-linker in the formation of aminoplast microcapsules, specifically using a diamine to cross-link melamine-formaldehyde pre-condensates, results in stable and performant microcapsules that are free from discoloration, with a shell structure comprising a terpolymer and polymeric stabilizers like acrylic copolymers and sodium polycarboxylates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resorcinol is used as a cross-linker in melamine-formaldehyde microcapsules, then stability and perfumery benefits are improved, but discoloration occurs
Solution Approach 1:
The patent changes the chemical parameter of the cross-linking agent from resorcinol to diamine. This substitution maintains the cross-linking function and stability of the microcapsule shell while eliminating the discoloration side effect. The diamine cross-linker forms a stable cross-linked network structure similar to resorcinol but without the harmful discoloration property.
2Ease of manufacture
If resorcinol is used to form aminoplast microcapsules, then desired perfumery benefits are achieved, but the slurry undergoes undesirable discoloration
Solution Approach 1:
The patent modifies the chemical composition parameter by replacing resorcinol with diamine in the microcapsule formulation. This change preserves the ease of manufacture and desired perfumery benefits while eliminating the discoloration issue that occurs during slurry preparation and storage.
3Object-generated harmful factors
If diamine is used as a cross-linker instead of resorcinol, then discoloration is eliminated, but shell structure composition changes
Solution Approach 1:
The patent performs a targeted parameter change by substituting the cross-linker type while maintaining the overall shell structure composition. The diamine cross-linker forms a cross-linked network that replicates the structural stability provided by resorcinol, ensuring the shell maintains its integrity and protective function without discoloration.
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 use of diamine as a cross-linker in forming aminoplast microcapsules provides a colorless, stable, and performant encapsulated perfume composition that maintains stability and perfumery benefits comparable to resorcinol-based microcapsules without discoloration, suitable for use in consumer products.
Implementation Method 1
the cross-linker is a diamine
Implementation Method 2
polymeric stabilizers like acrylic copolymers and sodium polycarboxylates
Data Source
AI summary
Encapsulated perfume composition comprising at least one aminoplast core-shell microcapsule dispersed in a suspending medium, the microcapsule comprising a perfume-containing core encapsulated in a shell, said shell comprising a network of cross-linked aminoplast resin, wherein 75-100% of the resin comprises 50-90%, preferably from 60-85%, of a terpolymer and from 10-50%, preferably from 10-25%, of a polymeric stabilizer; the terpolymer comprising: (a) from 20 – 35 wt%, preferably 22 – 30 % by weight of moieties derived from at least one triamine, (b) from 30 – 60 wt%, preferably 40 – 55 % by weight of moieties derived from at least one diamine, (c) from 20 – 35 wt%, preferably 22 – 30 % by weight of moieties derived from the group consisting of alkylene and alkylenoxy moieties having 1 to 6 methylene units, preferably to 4 methylene units and most preferably 1 methylene unit. The encapsulated perfume composition is useful for the storage and dissemination of fragrance in various products, such as laundry products and fabric care products.