Core-shell urethane resin particles for coating stability
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Solution Overview
Problem
Urethane resin particles synthesized with polyether polyol for flexibility often exhibit poor solvent resistance and storage stability in coating compositions, while using polycarbonate polyol for improved cohesion results in coatings with insufficient flexibility and stability.
Innovation Solution
The development of core-shell type urethane resin particles, where the core comprises a urethane resin made with polyether polyol and the shell comprises a urethane resin made with polycarbonate polyol, enhancing solvent resistance and flexibility while maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polyether polyol is used to obtain high flexibility, then flexibility is improved, but solvent resistance and storage stability deteriorate
Solution Approach 1:
The invention divides the urethane resin into two distinct segments: a core portion made from polyether polyol (providing flexibility) and a shell portion made from polycarbonate polyol (providing cohesion and stability). This segmentation allows each segment to independently contribute its advantageous properties without the drawbacks of the other, resolving the contradiction between flexibility and storage stability.
Solution Approach 2:
Different regions of the urethane resin particle are assigned different compositions tailored to specific functions: the core region uses polyether polyol for flexibility, while the shell region uses polycarbonate polyol for solvent resistance and storage stability. This local differentiation of material properties enables simultaneous achievement of both flexibility and stability.
2Reliability
If polycarbonate polyol is used to improve cohesion and storage stability, then storage stability is improved, but flexibility deteriorates
Solution Approach 1:
The urethane resin is segmented into core and shell portions, where the shell made from polycarbonate polyol provides the necessary cohesion and storage stability, while the core made from polyether polyol ensures flexibility is not lost. This segmentation allows polycarbonate polyol to be used at lower overall concentrations while maintaining stability.
Solution Approach 2:
The shell region is specifically designed with polycarbonate polyol to provide local cohesion and stability functions, while the core region maintains polyether polyol for flexibility. This localized assignment of material properties resolves the contradiction by providing stability only where needed (shell) while preserving flexibility in the core.
3Reliability
If small amount of polycarbonate polyol is used to improve storage stability, then storage stability is slightly improved, but flexibility is compromised
Solution Approach 1:
By segmenting the resin into core-shell structure, the invention enables effective use of small amounts of polycarbonate polyol concentrated in the shell region, maximizing its stabilizing effect while minimizing its impact on flexibility. The core region maintains polyether polyol for flexibility, so overall flexibility is preserved even with limited polycarbonate polyol content.
4Reliability
If excessively large amount of polycarbonate polyol is used to improve storage stability, then storage stability is improved, but desired flexibility cannot be obtained
Solution Approach 1:
The core-shell segmentation restricts polycarbonate polyol to the shell region only, preventing it from overwhelming the flexible core region. This spatial confinement ensures that even with sufficient polycarbonate polyol for stability, the flexible polyether polyol core maintains the desired flexibility of the overall coating film.
Solution Approach 2:
The shell region is locally optimized for stability with polycarbonate polyol, while the core region is locally optimized for flexibility with polyether polyol. This local quality differentiation prevents the flexibility-compromising effect of excessive polycarbonate polyol by limiting its presence to only the shell region.
Data Source
AI summary
The problem to be solved by the present invention is to provide urethane resin particles that, when used as a component of a coating composition, enable the resulting coating composition to have excellent storage stability and excellent degree of freedom of adjustment of physical properties of the obtained coating film. The present invention provides core-shell type urethane resin particles having a core-shell structure in which the core comprises a urethane resin obtained by using a polyol component comprising polyether polyol, whereas the shell comprises a urethane resin obtained by using a polyol component comprising polycarbonate polyol.