Levulinic Acid Ester Oximes for Blocked Isocyanate Polyurethanes
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Solution Overview
Problem
Current blocking agents for isocyanate compositions, such as butanone oxime, are toxic and pose health risks, necessitating the development of less toxic and bio-based alternatives.
Innovation Solution
A new blocking agent, oxime of an ester of gamma-ketoacid, particularly levulinic acid, is used to block isocyanate groups, forming urethane groups, which is synthesized from biomass-derived levulinic acid and offers reduced toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional blocking agents like butanone oxime are used, then isocyanate groups can be effectively blocked and deblocked, but the toxicity and health risks increase significantly
Solution Approach 1:
The patent changes the chemical structure parameter of the blocking agent from traditional oximes (like butanone oxime) to oximes of esters of gamma-ketoacids (such as levulinic acid esters). This structural parameter change maintains the blocking functionality while reducing toxicity, as evidenced by the lower carcinogenicity classification and reduced health hazards of the new agents compared to traditional ones.
Solution Approach 2:
The invention uses composite chemical structures combining ester groups with oxime groups derived from gamma-ketoacids. This composite structure (ester-oxime) provides both the blocking capability needed for isocyanate protection and the reduced toxicity profile, achieving a balance between functionality and safety that neither simple oximes nor esters alone could provide.
2Object-affected harmful factors
If bio-based blocking agents are used to reduce toxicity, then health and environmental safety improves, but the availability and industrial experience are limited
Solution Approach 1:
The patent employs levulinic acid, a bio-based platform chemical that can be produced from renewable biomass resources through established industrial processes. This self-service approach allows the system to generate its own blocking agent from renewable resources, reducing dependence on petrochemical sources and improving sustainability while maintaining industrial scalability.
Solution Approach 2:
The invention shifts the source parameter of the blocking agent from petrochemical origins to bio-based origins. By using levulinic acid esters derived from biomass, the patent changes the feedstock parameter while maintaining the functional performance needed for industrial applications, thereby improving environmental safety without sacrificing manufacturability.
3Reliability
If the blocking agent is released at deblocking temperature close to boiling point, then the isocyanate groups become free for reaction, but the blocking agent is released to the atmosphere causing environmental contamination
Solution Approach 1:
The patent modifies the deblocking temperature parameter by selecting blocking agents with appropriate dissociation characteristics. The oximes of esters of gamma-ketoacids are designed to deblock at temperatures that balance isocyanate activation with reduced volatile release, thereby maintaining reaction effectiveness while minimizing atmospheric contamination compared to traditional agents that require higher deblocking temperatures.
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 new blocking agent provides a safer and more environmentally friendly solution for isocyanate compositions, maintaining reactivity while minimizing health hazards and environmental impact.
Implementation Method 1
this blocking agent blocks an isocyanate group by forming an urethane group
Implementation Method 2
This blocked polyurethane will dissociate on heating to remove the protecting or blocking agent and release the reactive isocyanate group
Data Source
Figure 1
AI summary
The present invention relates to a new blocking agent for a blocked isocyanate composition consisting of an oxime of an ester of gamma-cetoacid. The present invention also relates to a method of manufacturing a blocked isocyanate composition and to a method of deblocking a blocked isocyanate composition. The present invention relates to the use of the blocked isocyanate composition obtained for manufacturing synthetic or artificial leather or in textile applications.