Aqueous Capsule Dispersion with Crosslinked Shells for Controlled Release
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Solution Overview
Problem
Existing nano- or microcapsules face issues such as low stability, low solvent resistance, high toxicity, and lack of temperature-controlled delivery, particularly in applications like laundry, cleaning, and drug delivery, where safer, more efficient, and controlled release is desired.
Innovation Solution
An aqueous dispersion of nano- or microcapsules with a polymeric shell comprising a resin having specific repeating units, formed by reacting oligomeric or polymeric compounds with amine compounds in a controlled environment, using interfacial polymerization to create capsules with improved stability and controlled release properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interfacial polycondensation is used to prepare capsules with polyurea or polyurethane walls, then capsule wall formation is achieved, but the capsules exhibit low stability, low solvent resistance, and high toxicity
Solution Approach 1:
The patent changes the chemical parameters of the capsule wall by using polyesters or polyethers instead of polyurea/polyurethane, and employs crosslinking agents to modify the wall structure. This substitution eliminates toxic isocyanates while improving stability and solvent resistance through different chemical bonding mechanisms.
Solution Approach 2:
The invention creates composite capsule walls by combining polyester or polyether base materials with crosslinking agents. This composite structure provides enhanced mechanical strength, improved solvent resistance, and reduced toxicity compared to simple polyurea/polyurethane walls, achieving multiple performance improvements simultaneously.
2Reliability
If conventional polyurea or polyurethane capsules are used, then capsule formation is achieved, but solvent resistance and stability remain low
Solution Approach 1:
The patent fundamentally changes the chemical composition parameters by replacing carbonyl-based polyurea/polyurethane structures with ester/ether-based polyester/polyether structures. This parameter change inherently improves solvent resistance since esters and ethers exhibit different solubility characteristics compared to urea/urethane groups, while the crosslinking further enhances compositional stability.
Solution Approach 2:
By creating a composite wall system of polyester/polyether plus crosslinking agent, the invention achieves synergistic effects where the base polymer provides flexibility and the crosslinking network provides rigidity and solvent resistance, resulting in superior overall stability compared to conventional single-material walls.
3Adaptability or versatility
If interfacial polycondensation is used for capsule production, then capsule wall material is formed, but temperature-controlled delivery of active material is not achieved
Solution Approach 1:
The patent introduces dynamic temperature-responsive behavior into the capsule wall by incorporating polymers with lower critical solution temperatures (LCST) or upper critical solution temperatures (UCST). These dynamic properties allow the wall to reversibly change its permeability and mechanical properties in response to temperature changes, enabling controlled release without complex additional mechanisms.
Solution Approach 2:
The invention utilizes temperature as a control parameter to trigger phase transitions or conformational changes in the polymer wall. By selecting polymers with specific transition temperatures, the system can be designed to release active material at predetermined temperature thresholds, adding adaptability while maintaining relatively simple interfacial polycondensation manufacturing.
4Reliability
If conventional capsule wall materials are used, then capsule formation is achieved, but wall permeability is high leading to uncontrolled release
Solution Approach 1:
The patent changes the permeability parameter by selecting polyester or polyether base materials with inherently lower permeability than polyurea/polyurethane, and further reduces permeability through crosslinking. The crosslinked network structure creates tortuous diffusion paths and reduces free volume, thereby controlling molecular transport and enabling sustained, controlled release profiles.
Solution Approach 2:
The composite wall structure of polyester/polyether combined with crosslinking agent creates a dual-function system where the base polymer provides the matrix structure and the crosslinking densifies the network. This composite approach achieves optimized permeability that balances protection of active material with controlled release capability, preventing both high permeability leakage and complete impermeability.
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 capsules provide safer, more stable, and efficient delivery of active materials with controlled release, enhancing applications in laundry, cleaning, and drug delivery by improving solvent resistance and release profiles.
Implementation Method 1
formed by reacting oligomeric or polymeric compounds with amine compounds in a controlled environment, using interfacial polymerization to create capsules
Data Source
AI summary
An aqueous dispersion of particles comprising a resin having at least one repeating unit of formula I, II and/or III and which is obtainable by contacting in a liquid comprising water, a compound A comprising at least 2 functional groups selected from the group of functional groups —X—C(═O)—CHR1-C(═O)—R2, —X—C(═O)—C≡C—R2; or —X—C(═O)—CR1=CR2-NR11R12, the functional groups are linked by a linking group comprising a polyester, polyether, polyolefin, polydimethylsiloxane or polycarbonate chain with a compound B comprising at least two —NH2, —NH3+ or —N═C═O, wherein X, R1, R2, R3, R11 and R12 have the same meaning as that defined in the claims and w. The invention also includes a method of producing the aqueous dispersion.