Blocked Polyisocyanate Dispersion for Stable High-Temperature Crosslinking
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Solution Overview
Problem
Existing waterborne polyurethane dispersions face challenges in achieving high solvent and chemical resistance, elasticity, and mechanical stress, while solvent-free production is hindered by viscosity issues and storage stability is compromised without solvents.
Innovation Solution
A process involving reacting polyisocyanate with thermally releasable primary monofunctional alcohols, followed by non-ionic hydrophilizing agents, and further blocking with primary monofunctional alcohols to produce a blocked polyisocyanate, which is then dispersed in water, ensuring high storage stability and versatility in formulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multilayer structure with multiple release agents is used, then release performance for different materials is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies a single release agent layer that can function with multiple different mold materials (metal, ceramic, glass, composite) and reinforcements (fiber, particulate, foam), eliminating the need for multiple specialized release agent layers while maintaining universal release performance across diverse molding applications
Solution Approach 2:
The patent combines the functions of multiple release agents into a single release agent layer that provides release capability for both the mold surface and reinforcement materials simultaneously, merging what were previously separate functional requirements into one integrated layer
2Ease of operation
If conventional release agents are used, then release function is provided, but production efficiency decreases due to additional processing steps
Solution Approach 1:
The patent merges the release agent application step with the gel coating step by incorporating release agents into the gel composition itself, allowing both the gel layer formation and release agent deposition to occur in a single processing operation rather than requiring separate sequential steps
Solution Approach 2:
The release agents are pre-incorporated into the gel composition during manufacturing, so that when the gel is applied to the mold, the release function is already provided without requiring additional post-coating processing steps
3Adaptability or versatility
If gel coating is applied to provide release function, then release performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines the gel coating process and release agent application into a single integrated process where the gel composition containing dispersed release agents is applied directly to the mold surface, eliminating the need for separate gel coating and release agent deposition steps
Solution Approach 2:
The gel composition serves multiple functions simultaneously: it provides the release function through incorporated release agents, acts as a protective coating layer, and can be applied using standard gel coating equipment, making the process versatile and eliminating the need for specialized multi-step manufacturing
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 resulting blocked polyisocyanate enables high-temperature conversion to unblocked form, providing stable aqueous dispersions suitable for various coatings, adhesives, and elastomers with improved storage stability and performance.
Implementation Method 1
The release agent can be any material that provides release function for both mold and reinforcement materials. The release agent is dispersed throughout the gel coating.
Implementation Method 2
Gel coatings have been used to provide release function for the gel coating itself.
Data Source
AI summary
The present invention relates to a process for preparing at least one blocked polyisocyanate, comprising the following steps: (A) reacting at least one polyisocyanate with at least one thermally cleavable blocking agent selected from the group consisting of primary, monofunctional alcohols and mixtures thereof to obtain at least one partially blocked polyisocyanate, (B) reacting the at least one partially blocked polyisocyanate from step (A) with at least one non-ionic hydrophilizing agent to obtain an intermediate product, and (C) reacting the intermediate product obtained in step (C) with at least one thermally cleavable blocking agent selected from the group consisting of primary, monofunctional alcohols and mixtures thereof, to obtain the at least one blocked polyisocyanate. The invention further relates to a correspondingly obtained blocked polyisocyanate, to the use of the blocked polyisocyanate for producing coating agents, adhesives, sealants or elastomers, to corresponding coating agents, adhesives, sealants or elastomers, and to substrates that are provided with coatings obtained using the at least one blocked polyisocyanate according to the invention.