Polyisocyanate Preparation Peroxide Control
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Solution Overview
Problem
Hydrophilically modified polyisocyanate crosslinkers used in aqueous paint systems often exhibit color instability due to varying peroxide content in solvents, leading to inconsistent product quality and limited usability.
Innovation Solution
Developing polyisocyanate preparations with a solvent component having a peroxide content of no more than 70 mg/l H2O2 equivalents, ensuring the calculated peroxide content in the preparation is a maximum of 20 mg/l, which stabilizes the color and reproducibility of the solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If solvents with higher peroxide content are used to dilute hydrophilically modified polyisocyanate crosslinkers, then viscosity is reduced and ease of incorporation into aqueous binder is improved, but color stability deteriorates and product quality consistency worsens
Solution Approach 1:
The patent applies parameter changes by strictly controlling the peroxide content of the solvent to at most 70 mg/l H2O2 equivalents, and the calculated peroxide content of the final preparation to at most 20 mg/l H2O2 equivalents. This quantitative parameter control resolves the contradiction by selecting a specific peroxide content range that maintains both ease of operation and color stability.
2Adaptability or versatility
If solvents with varying peroxide content are used, then flexibility in solvent selection is improved, but manufacturing precision and product quality consistency deteriorate
Solution Approach 1:
The patent establishes specific peroxide content parameters (at most 70 mg/l H2O2 equivalents in solvent, at most 20 mg/l in final preparation) that define the acceptable range for solvent selection. This allows flexibility within bounded parameters while ensuring manufacturing precision and consistent product quality.
3Duration of action of moving object
If polyisocyanate solutions are stored for prolonged periods, then availability for use is improved, but color stability deteriorates due to oxidation
Solution Approach 1:
The patent applies preliminary action by controlling the peroxide content of the solvent before the storage period begins. By ensuring the solvent has at most 70 mg/l H2O2 equivalents peroxide content before storage, the preparation maintains color stability throughout the storage period, enabling prolonged availability without deterioration.
4Ease of manufacture
If conventional coating solvents are used to dilute polyisocyanate crosslinkers, then ease of formulation is improved, but color numbers increase and usability for high-quality coatings is limited
Solution Approach 1:
The patent changes the peroxide content parameter of the solvent from conventional levels (which can be much higher) to a restricted range of at most 70 mg/l H2O2 equivalents. This parameter change enables ease of formulation while maintaining low color numbers and usability for high-quality waterborne coating systems.
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 approach results in color-stable and reproducible polyisocyanate solutions, preventing significant color changes during storage, even at elevated temperatures, thus maintaining high-quality paint system performance.
Implementation Method 1
it is known to the person skilled in the art that the colour numbers of polyisocyanates can be significantly reduced by oxidation, for example by addition of peroxides
Data Source
AI summary
The invention relates to a polyisocyanate preparation containing at least one polyisocyanate component A) hydrophilically modified with at least one ionic emulsifier and a solvent component E) consisting of at least one organic solvent, characterized in that the solvent component E) has a content of peroxides of not more than 70 mg/l of H2O2 equivalents, wherein this value is the average peroxide content of all organic solvents present in the solvent component E) and the polyisocyanate component A) and the solvent component E) are present in amounts such that the calculated peroxide content of the polyisocyanate preparation based on the sum of A) and E) is not more than 20 mg/l of H2O2. The invention further relates to the use thereof and to coating compositions and substrates coated with these coating compositions.