Conductive Roll Using Low-Tin Catalyst for Uniform Carbon Black
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Solution Overview
Problem
Conductive rolls with carbon black distribution issues due to environmental dependencies, such as temperature and humidity, result in nonuniform electrical resistance and poor image quality in printing products, as the urethane reaction is difficult to control to achieve uniform carbon black distribution.
Innovation Solution
A conductive roll with a conductive elastic layer prepared by reacting polyether-based polyol with diisocyanate using a tetravalent organotin-based catalyst with a tin content of 18.7% or less, along with a surface treatment layer containing an isocyanate component and carbon black, to suppress bubble entrapment and ensure uniform carbon black dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mold temperature is increased to accelerate urethane reaction, then the curing speed improves, but carbon black reaggregates due to heat, causing nonuniform distribution
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by selecting specific organometallic compounds (tin octylate, bismuth triglycidate, or zirconium octoxide) with controlled catalytic activity. This allows the urethane reaction to proceed at an optimal rate that cures the material before carbon black reaggregation occurs, even at elevated mold temperatures, thereby maintaining uniform carbon black distribution while achieving adequate curing speed.
2Productivity
If the catalyst amount is increased to accelerate urethane reaction, then the reaction rate improves, but the raw materials thicken in the mixing stage, causing bubble entrapment
Solution Approach 1:
The patent optimizes the catalyst concentration parameter within a specific range (0.01-0.1 wt% for tin octylate, 0.003-0.03 wt% for bismuth triglycidate, or 0.003-0.03 wt% for zirconium octoxide). This controlled parameter change ensures the reaction proceeds at a moderate rate during mixing, preventing excessive thickening and bubble entrapment, while still achieving sufficient curing during molding.
3Ease of manufacture
If conventional catalysts are used to control urethane reaction, then the reaction can be initiated, but carbon black distribution becomes nonuniform due to difficult control of reaction timing
Solution Approach 1:
The patent introduces specific organometallic compounds as intermediary catalysts that mediate the urethane reaction between isocyanate and hydroxyl groups. These catalysts provide intermediate catalytic activity that allows sufficient reaction time for uniform carbon black distribution while still achieving complete curing. The intermediaries enable precise control over the reaction timeline, preventing both premature thickening and delayed curing.
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 solution minimizes environment-dependent variations in electrical characteristics, achieving a uniform carbon black distribution and improved image quality across different environmental conditions.
Implementation Method 1
reacting at least one polyol consisting essentially of a polyether-based polyol with a diisocyanate with the use of a tetravalent organotin-based compound having a tin content of 18.7% or less by weight as a catalyst
Implementation Method 2
The conductivity of the elastic layer being can be provided by carbon black
Data Source
AI summary
A conductive roll having at least one conductive elastic layer on the outer periphery of a core bar, the conductive elastic layer being granted conductivity by carbon black, is provided. The conductive elastic layer is prepared by reacting at least a polyol consisting essentially of a polyether-based polyol with a diisocyanate with the use of a tetravalent organotin-based compound having a tin content of 18.7% or less by weight as a catalyst. A method for producing the conductive roll is also provided.