Polymeric microparticles
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Solution Overview
Problem
Existing microencapsulation methods using acrylic copolymers of the HASE type often result in microparticles that are too hard, prone to cracking, or lack flexibility, making them unsuitable for applications requiring adhesion to surfaces or encapsulation of certain active principles.
Innovation Solution
The development of polymer-coated microparticles comprising a combination of two solid-liquid phase change materials with distinct phase transition temperatures and an acrylic copolymer of the HASE type, allowing for adjustable flexibility and enhanced active agent encapsulation and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If acrylic copolymers of the HASE type are used for microencapsulation, then encapsulation capability is improved, but the microparticles become too hard and prone to cracking
Solution Approach 1:
The invention uses a composite polymer system combining HASE-type acrylic copolymer with at least one additional polymer component (such as polyurethane, polyester, or polyacrylonitrile) to create microparticles that encapsulate active agents. This composite structure provides both encapsulation capability and improved mechanical flexibility, resolving the contradiction between encapsulation performance and mechanical brittleness.
Solution Approach 2:
The invention modifies the polymer composition parameters by adjusting the ratios of HASE copolymer to additional polymer components, and by selecting polymers with specific glass transition temperatures and mechanical properties. This parameter optimization allows tuning of the microparticle hardness and flexibility while maintaining encapsulation effectiveness.
2Strength
If microparticles are made harder for improved structural integrity, then mechanical strength is improved, but flexibility and adhesion to surfaces deteriorate
Solution Approach 1:
By combining HASE-type acrylic copolymer with flexible polymer components having different mechanical properties and glass transition temperatures, the invention creates a composite microparticle structure that simultaneously achieves structural integrity and surface adhesion capability. The synergistic interaction between different polymer phases provides both hardness and flexibility.
Solution Approach 2:
The composite polymer system creates local regions with different mechanical properties within the microparticle structure. The HASE copolymer provides structural framework while the additional polymer components create softer regions that enhance flexibility and adhesion, allowing the microparticle to exhibit both strength and compliance as needed.
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 microparticles exhibit improved flexibility and mechanical properties, enabling better adhesion and encapsulation of a wide range of active principles, with controlled release mechanisms responsive to pH, temperature, or friction.
Implementation Method 1
at least one solid-liquid phase change material having a phase transition temperature Tf 1 varying from 35° C. to 90° C.; vs. at least one solid-liquid phase change material having a phase transition temperature Tf 2 of less than or equal to 30° C.
Implementation Method 2
the use of these microparticles or aqueous dispersions comprising them for releasing an active agent in response to a change in pH
Data Source
AI summary
The invention relates to microparticles having a polymeric envelope, and to aqueous dispersions comprising said microparticles. The microparticles with a polymeric envelope comprise: a) at least one HASE-type acrylic copolymer; b) at least one solid-liquid phase-change material having a phase transition temperature Tf1 which is higher than or equal to 20°C; c) at least one solid-liquid phase-change material having a phase transition temperature Tf2 which is lower than or equal to 30°C, on the condition that Tf2 is lower than Tf1; and d) optionally at least one active agent.