Nonionic Polyurethane Dispersion for Fiber Optic Sizing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aqueous coating systems for fiber optics face challenges with stability and compatibility due to complex hydrolysis and condensation processes involving functional silanes, leading to unstable systems and restricted processing times.
Innovation Solution
Aqueous UV-hardening dispersion containing a reaction product of polyisocyanates with specific structure units, monohydroxy-functional acryloyl groups, non-hydrophilic components with isocyanate groups, and diols or diamines, which lacks ionogenic or ion-hydrophilic groups, ensuring high storage stability and improved compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If functional silanes are used in glass fiber sizing formulations, then crosslinking and adhesion properties are improved, but complex hydrolysis and condensation processes occur leading to system instability and reduced processing time
Solution Approach 1:
The patent removes functional silanes from the formulation entirely, replacing them with a polyisocyanate-based dispersion system. This extraction eliminates the problematic hydrolysis and condensation processes while maintaining adhesion through alternative chemistry (isocyanate groups reacting with hydroxyl and carboxyl groups on glass fiber surfaces).
Solution Approach 2:
The invention changes the chemical parameters of the sizing agent by using a water-dispersible polyisocyanate system with specific functionality (NCO content of 1-5%) instead of traditional silane-based systems. This parameter change allows the system to achieve crosslinking and adhesion without the instability caused by silane hydrolysis and condensation.
2Reliability
If traditional aqueous coating systems with functional silanes are used, then crosslinking capability is achieved, but processing time is restricted and storage stability is reduced
Solution Approach 1:
The patent replaces the chemical mechanism of silane crosslinking (which requires hydrolysis and condensation steps) with an isocyanate-based crosslinking mechanism. The isocyanate groups react directly with hydroxyl and carboxyl groups on glass fiber surfaces and within the resin matrix, eliminating the need for complex multi-step hydrolysis and condensation processes, thereby extending processing time and improving storage stability.
3Ease of operation
If ionically hydrophilized polyisocyanates are used, then water dispersibility is improved, but compatibility in formulations is reduced and unstable products form
Solution Approach 1:
The patent applies non-ionogenic hydrophilizing groups specifically to the polyisocyanate molecule, creating localized water-dispersible regions without introducing ionic groups throughout the system. This local quality approach allows water dispersibility while maintaining formulation compatibility, as the non-ionogenic nature of the hydrophilizing groups prevents unwanted ionic interactions that would reduce compatibility.
4Reliability
If complex hydrolysis and condensation processes are allowed to occur, then crosslinking is achieved, but system stability decreases and processing becomes more difficult
Solution Approach 1:
The patent extracts and eliminates the hydrolysis and condensation processes from the crosslinking mechanism. Instead of allowing water to hydrolyze silane groups followed by condensation to form crosslinks, the system uses direct isocyanate-isocyanurate crosslinking that occurs without hydrolysis, significantly simplifying the chemical process while maintaining effective crosslinking.
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 dispersion provides a stable, non-ionically hydrophilized polyisocyanate system with enhanced storage stability and improved processing times, suitable for fiber optic applications without forming unstable products.
Implementation Method 1
an aqueous UV-curable dispersion, in particular for use as a glass fiber sizing agent... comprising at least one reaction product composed of a) at least one polyisocyanate... b) at least one monohydroxy-functional compound containing acryloyl groups... c) at least one component containing non-ionically hydrophilizing groups and having at least one isocyanate-reactive group
Implementation Method 2
The dispersions according to the invention are purely non-ionically hydrophilized polyisocyanates... The acrylate-functional coating agents known from the prior art show a lack of compatibility in typical formulations for glass fiber sizing, which, for example, significantly limits the processing time. One problem with the use of functional silanes in glass fiber sizing is that the complex hydrolysis and condensation processes of the other components in combination with functional silanes in typical glass fiber sizing often produce (intermediate) products that lead to unstable systems.
Data Source
AI summary
The present invention relates to an aqueous UV-curable dispersion at least comprising a reaction product composed of a) at least one polyisocyanate having an average isocyanate functionality of at least 2.2, of which preferably at least one polyisocyanate is an oligomeric polyisocyanate having urethane, biuret, allophanate, iminooxadiazinedione and/or isocyanurate structural units; b) at least one monohydroxy-functional compound containing acryloyl groups, c) at least one component which contains non-ionic hydrophilizing groups and has at least one further isocyanate-reactive group and d) at least one diol, triol, diamine and/or triamine, the reaction product having no ionogenic or ionically hydrophilizing groups. The invention also relates to a process for the preparation of the dispersion, the use of the dispersion for the preparation of glass fibre sizing agents, a glass fibre sizing agent at least containing said type of dispersion, glass fibres provided with a sizing agent obtainable using said type of dispersion, a process for the preparation of glass fibre-reinforced plastics, and a corresponding glass fibre-reinforced plastic.