Polyurea Capsule Wall Stability and Fragrance Release
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Solution Overview
Problem
Existing polyurea or polyurethane capsules face issues such as low olfactory intensity, low stability, high toxicity, and problematic deposition on target surfaces, particularly in applications like laundry, cleaning, and personal care, where quicker and easier release or less mechanical strength are desired.
Innovation Solution
Development of polyurea or polyurethane capsule compositions with a polyurea or polyurethane wall formed from a reaction product of a polyisocyanate and a cross-linking agent in the presence of a capsule formation aid, such as carboxymethyl cellulose and polystyrene sulfonates, with an oil core containing fragrances, flavors, or malodor counteracting agents, and using ethylenediamine or other cross-linking agents like 1,3-diaminopropane, to enhance stability and deposition efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyurea or polyurethane capsules are used for encapsulation, then mechanical strength is achieved, but olfactory intensity is low and stability is poor
Solution Approach 1:
The patent changes the chemical parameters of the capsule wall by using reaction products of polyisocyanates with polyols or polyamines, along with specific crosslinking agents and capsule formation aids. This modifies the wall's permeability and structural properties, enabling both high stability and enhanced olfactory intensity through optimized molecular architecture rather than simply increasing wall thickness or strength.
Solution Approach 2:
The invention employs composite capsule wall materials comprising multiple components: polyisocyanate reaction products, crosslinking agents (such as ethylenediamine or 1,3-diaminopropane), and capsule formation aids. This composite structure allows simultaneous achievement of mechanical strength, chemical stability, and controlled fragrance release properties that single-material walls cannot provide.
2Strength
If polycondensation reaction is used to form capsule walls, then mechanical strength is improved, but deposition on target surfaces becomes problematic
Solution Approach 1:
The patent modifies the surface properties of the capsule wall by incorporating specific crosslinking agents and capsule formation aids that alter the wall's surface charge, hydrophobicity, and adhesion characteristics. These parameter changes enable the capsules to maintain mechanical strength while improving their ability to deposit efficiently on target surfaces such as fabrics or surfaces in cleaning applications.
3Reliability
If conventional capsule wall materials are used, then structural integrity is maintained, but toxicity is high
Solution Approach 1:
The invention changes the chemical composition parameters of the capsule wall by selecting specific polyisocyanate derivatives, crosslinking agents, and capsule formation aids that result in lower toxicity. The reaction products formed have improved biocompatibility and reduced harmful effects while maintaining the necessary structural integrity for capsule functionality.
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 capsule compositions exhibit high perceived olfactory intensity, prolonged stability, low toxicity, and improved deposition on surfaces, making them suitable for consumer products like shampoos, soaps, and fabric softeners, with enhanced fragrance release profiles.
Implementation Method 1
the polycondensation reaction will take place. Thus, the small droplets of the water-immiscible phase will be surrounded by the capsule wall formed by polycondensation of the isocyanate and the polyalcohol or polyamine as starting materials
Implementation Method 2
Suitable emulsifiers are often utilized to aid in the preparation and stabilization of the emulsion
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
Poiyurea or polyurethane capsule compositions. A subset of these compositions contain a plurality of capsules and a capsule formation aid, in which each of the capsules contains a poiyurea or polyurethane wall and an oil core; the poiyurea or polyurethane wall is formed of a reaction product of a polyisocyanate and a cross-linking agent in the presence of the capsule formation aid; and the oil core contains an active material. The polyisocyante, cross-linking agent, and capsule formation aids are described herein. Also disclosed are methods of preparing poiyurea and polyurethane capsule compositions, as well as consumer products containing one of these compositions.