Polyurea Microcapsules for Controlled Fragrance Release
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Solution Overview
Problem
Polyurea and polyurethane microcapsules have not been effectively applied for the release of benefit agents in laundry, cleaning, surface care, and personal care products, where quicker and easier release, and controlled permeability are desired, unlike their use in agrochemical applications requiring mechanical strength and slow release.
Innovation Solution
A method for preparing polyurea capsule compositions involving an oil phase with a fragrance and aliphatic or aromatic polyisocyanate, surfactant solution, cross-linking agent, and curing process to form microcapsules suitable for consumer products like shampoos and fabric refreshers, with specific surfactants and cross-linking agents enhancing fragrance release and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyurea and polyurethane microcapsules are used for agrochemical applications requiring mechanical strength and slow release, then mechanical strength and durability are improved, but release speed and ease of application are worsened
Solution Approach 1:
The patent applies parameter changes by modifying the polymer composition parameters - using polyisocyanates with lower molecular weight and specific functional groups that reduce mechanical strength but enhance fragrance release properties. This allows transition from agrochemical application parameters to consumer care application parameters
Solution Approach 2:
The patent introduces dynamic release characteristics by formulating microcapsules that adapt their release rate based on environmental conditions such as agitation, temperature, and pH changes typical in laundry and cleaning applications, rather than maintaining constant slow release
2Stability of the object's composition
If polyurea and polyurethane microcapsules are designed for rugged applications with high mechanical strength, then capsule wall integrity is improved, but permeability control and fragrance release are worsened
Solution Approach 1:
The patent changes the chemical composition parameters of the capsule wall by using polyisocyanates with specific functional groups and molecular weights that create a less dense polymer network, thereby increasing permeability while maintaining sufficient structural integrity for consumer care applications
Solution Approach 2:
The patent employs composite material strategies by combining polyisocyanates with specific chain extenders and crosslinking agents in controlled ratios to create a composite polymer structure that balances permeability and mechanical properties for fragrance delivery
3Strength
If conventional polycondensation methods are used for microcapsule preparation, then mechanical strength is improved, but manufacturing complexity and process time are worsened
Solution Approach 1:
The patent applies preliminary action by pre-selecting and pre-mixing specific polyisocyanate components before the polycondensation reaction, which simplifies the overall process by reducing the number of formulation adjustments needed during production while maintaining mechanical strength
Solution Approach 2:
The patent modifies reaction parameters such as temperature, catalyst selection, and monomer ratios to optimize the polycondensation process for both mechanical strength and manufacturing efficiency, reducing process complexity through parameter optimization
4Duration of action of stationary object
If polyurea and polyurethane microcapsules are designed for slow time-release in agrochemicals, then duration of action is improved, but consumer benefits and release controllability are worsened
Solution Approach 1:
The patent introduces dynamic release characteristics by formulating microcapsules that adapt their release rate based on environmental conditions such as agitation, temperature, and pH changes typical in laundry and cleaning applications, enabling responsive release control
Solution Approach 2:
The patent changes the polymer composition parameters - using polyisocyanates with lower molecular weight and specific functional groups that reduce mechanical strength but enhance fragrance release properties
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 produces microcapsules with excellent storage stability and controlled fragrance release, suitable for various consumer products, providing enhanced consumer benefits through precise control of release profiles and improved mechanical stability.
Implementation Method 1
Interfacial polycondensation is a known technique for preparing microcapsules... the polycondensation reaction will take place... polycondensation of the isocyanate and the polyalcohol or polyamine as starting materials
Implementation Method 2
the two phases are mixed by high shear mixing to form an oil-in-water emulsion... Suitable emulsifiers are often utilized to aid in the preparation and stabilization of the emulsion
Implementation Method 3
preparing a surfactant solution; emulsifying the oil phase into the surfactant solution to form a fragrance emulsion
Implementation Method 4
adding a cross-linking agent to the fragrance emulsion to form a capsule slurry... curing the capsule slurry
Data Source
AI summary
Polyurea capsules that encapsulate active materials in polymeric walls resulting from the polymerization of an aliphatic polyisocyanate and a cross-linking agent such as a diamine, amphoteric amine or guanidine amine/salt are provided as are consumer products containing said polyurea capsules and for methods for producing such capsules.