Hydrogenated Nitrile Rubber Phosphine Sulfide Modulus
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Solution Overview
Problem
Current hydrogenation processes for nitrile rubbers using phosphane or diphosphanes as co-catalysts result in vulcanizates with unsatisfactory modulus levels and compression set properties, especially after long storage at high temperatures, due to residual phosphane or diphosphane content.
Innovation Solution
Converting phosphane or diphosphane into their sulfide forms after hydrogenation using sulfur donors, which maintains good vulcanizate properties without the need for large halide separation or introduction, thereby achieving improved modulus and compression set values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphane or diphosphane is used as co-catalyst in hydrogenation of nitrile rubber, then hydrogenation rate and catalyst efficiency are improved, but residual phosphane or diphosphane content negatively affects vulcanizate properties (modulus level and compression set)
Solution Approach 1:
The patent converts the harmful residual phosphane or diphosphane into beneficial phosphine sulfide or diphosphane sulfide by reacting with sulfur donors (such as disulfides, polysulfides, or sulfur compounds) during or after the hydrogenation process. This transformation eliminates the negative effects on vulcanizate properties while maintaining the catalytic benefits of the original phosphane/diphosphane co-catalyst.
Solution Approach 2:
The patent changes the chemical state of the phosphane/diphosphane residue by introducing sulfur donors that transform it into phosphine sulfide or diphosphane sulfide. This parameter change (from phosphane to phosphine sulfide) fundamentally alters the properties of the residual compound, converting it from harmful to beneficial or neutral, thereby resolving the contradiction between maintaining high hydrogenation efficiency and achieving good vulcanizate properties.
2Reliability
If residual phosphane or diphosphane is removed through halide separation, then vulcanizate properties are improved, but process complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of removing the harmful phosphane/diphosphane through complex separation processes, the patent converts it into phosphine sulfide or diphosphane sulfide by reacting with sulfur donors. This in-situ transformation eliminates the need for complex halide separation equipment and processes, significantly simplifying the manufacturing workflow while achieving the same or better vulcanizate properties.
Solution Approach 2:
The sulfur donor acts as an intermediary substance that mediates the transformation of harmful phosphane/diphosphane into beneficial phosphine sulfide/diphosphane sulfide. This intermediary approach avoids the need for direct removal or separation of the original compound, thereby simplifying the process by replacing complex separation equipment with a simple chemical reaction step.
3Reliability
If phosphane or diphosphane content is reduced to improve vulcanizate properties, then compression set and modulus level are improved, but hydrogenation efficiency and catalyst performance decrease
Solution Approach 1:
The patent allows the use of phosphane/diphosphane co-catalysts at effective levels for high hydrogenation efficiency, then converts the resulting residues into phosphine sulfide/diphosphane sulfide. This two-step approach (use then convert) resolves the contradiction by first maximizing hydrogenation efficiency with adequate co-catalyst levels, then eliminating the harmful effects through sulfur donor treatment, thereby achieving both high productivity and good vulcanizate properties.
Solution Approach 2:
The sulfur donor is introduced during or immediately after the hydrogenation process to convert phosphane/diphosphane residues before they can negatively affect vulcanizate properties. This preliminary action ensures that the full benefits of phosphane/diphosphane co-catalysts are utilized during hydrogenation, while the harmful residues are promptly converted, thereby maintaining both high efficiency and good final properties.
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 process results in hydrogenated nitrile rubbers with enhanced modulus and compression set values, even after storage at high temperatures, while minimizing the negative effects of phosphane or diphosphane residues.
Implementation Method 1
converting the phosphine or diphosphane used in the hydrogenation into phosphine sulfides or diphosphine sulfides by reaction with sulfur donors
Implementation Method 2
For the hydrogenation of nitrile rubber with homogeneously soluble rhodium and/or ruthenium-containing hydrogenation catalysts, the addition of phosphanes or diphosphanes as a co-catalyst has proven useful
Data Source
AI summary
The invention relates to novel hydrogenated nitrile rubbers containing phosphine sulfides and/or diphosphine sulfides, a method for the production thereof, vulcanizable mixtures based on said hydrogenated nitrile rubbers, and vulcanized products obtainable by said method. The hydrogenated nitrile rubbers are characterized by an excellent property profile, in particular in respect of the modulus at different tensile stresses and the compression set following storage at high temperatures.