Perfume Microcapsule Adhesion via Polysiloxane Shell
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Solution Overview
Problem
Microencapsulated perfumes face challenges in adhering to substrates like hair or fabric, which are washed with products containing surfactants, leading to the removal of the microencapsulated perfume.
Innovation Solution
Core-shell microcapsules with a cross-linked polymeric shell, formed by interfacial polymerization using functionalized polysiloxane, polyisocyanate, and polyamine, providing silicone-urethane and urea linkages, are developed. The shell is flexible, adhesive, and resistant to shear forces, ensuring perfume longevity and controlled release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microencapsulated perfume is applied to substrate (hair or fabric), then fragrance delivery is achieved, but surfactants in washing products remove the microencapsulated perfume from the substrate
Solution Approach 1:
The shell is formed as a composite material comprising polysiloxane and melamine formaldehyde resin cross-linked with polyisocyanate, combining the adhesive properties of polysiloxane with the cross-linked network of melamine formaldehyde resin to resist surfactant removal
Solution Approach 2:
The shell composition and cross-linking density are optimized to balance adhesion to substrate and resistance to surfactant attack, with specific ratios of polysiloxane to melamine formaldehyde resin and controlled cross-linking extent to achieve desired performance
2Reliability
If the shell is made more adhesive to improve attachment to substrate, then perfume longevity improves, but the shell may become less resistant to shear forces and washing
Solution Approach 1:
The composite shell structure combines polysiloxane chains providing flexibility and adhesion with melamine formaldehyde resin providing rigid cross-linked network for shear resistance, achieving both attachment and mechanical strength
Solution Approach 2:
The shell exhibits different local properties: regions closer to substrate provide adhesion through polysiloxane, while the cross-linked melamine formaldehyde resin network throughout provides overall structural strength and shear resistance
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 effectively adhere to hair and resist removal during washing, providing sustained fragrance release and maintaining perfume longevity in aqueous and elevated temperature environments.
Implementation Method 1
the cross-linked polymeric shell is the reaction product of a functionalized polysiloxane, a polyisocyanate and a polyamine
Implementation Method 2
wherein the cross-linked polymeric shell comprises a mixture of polysiloxane and a melamine formaldehyde resin cross-linked with polyisocyanate
Implementation Method 3
The polymerization is controlled by diffusion, so the growth speed of the microcapsule's shell will decrease as the shell thickness increases
Data Source
AI summary
According to the invention, a core-shell microcapsule is provided comprising a cross-linked polymeric shell encapsulating a perfume-containing core, wherein the cross-linked polymeric shell is the reaction product of a functionalized polysiloxane, a polyisocyanate and a polyamine and wherein the functionalized polysiloxane comprises a polysiloxane backbone, one or more ethoxylated alcohol side chains and one or more substituted or unsubstituted alkyl or aliphatic cycloalkyl side chains.