Oxidized Carbon Black in Polyamic Acid for Semiconductive Belts

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Solution Overview

Problem

Current methods for producing semiconductive polyimide belts with high carbon black content face challenges in achieving uniform dispersion, leading to poor process efficiency, mechanical properties, and image quality due to low solid content and increased viscosity, along with environmental and safety concerns from impurities in carbon black production processes.

Innovation Solution

A carbon black-dispersed polyamic acid solution with a volatile content of 2-6% obtained through oxidation treatment of oil furnace process carbon black, allowing for a high carbon black load of 20-30 weight% and improved fluidity and dispersion stability, enabling precise control of semiconductivity and high-quality image formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon black is added to polyamic acid solution to increase carbon black content, then semiconductivity is improved, but viscosity increases and dispersion uniformity deteriorates

Engineering Contradiction:
ImprovesemiconductivityVSAvoidviscosity increase
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the surface properties of carbon black particles through oxidation treatment, modifying their chemical composition and surface charge characteristics. This parameter change enables better interaction with the polyamic acid solution, achieving uniform dispersion at high carbon black content (20-30 wt%) without excessive viscosity increase

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a specific type of oxidized carbon black as an intermediary substance that mediates between the conductive requirements and the dispersion stability requirements. The oxidized carbon black particles act as individual dispersible units rather than aggregates, serving as an effective intermediary that provides both conductivity and uniform distribution

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If carbon black is added to polyamic acid solution to achieve high carbon black content, then electrical resistance is reduced, but dispersion stability deteriorates due to aggregation

Engineering Contradiction:
Improveelectrical resistanceVSAvoiddispersion stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies oxidation treatment to change the surface parameters of carbon black, including surface charge density and chemical functional groups. This parameter modification prevents particle aggregation by creating electrostatic repulsion and improves dispersion stability while maintaining high carbon black content for achieving desired electrical resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality differences in the carbon black particles through oxidation, where the surface properties are modified while the core structure remains intact. This local modification at the particle surface level enables individual particle stability without affecting the overall conductive network formation

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If channel process carbon black is used to improve dispersibility, then dispersion stability is improved, but harmful impurities increase

Engineering Contradiction:
Improvedispersion stabilityVSAvoidimpurities
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the typically harmful effect of oxidation (which can create impurities) into a beneficial process by carefully controlling the oxidation treatment of carbon black. The controlled oxidation improves dispersibility and dispersion stability while the subsequent processing removes unwanted byproducts, transforming a potentially harmful process into a beneficial one

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the production parameters by using oil furnace process carbon black as the base material and applying controlled oxidation treatment with specific parameters (temperature, time, oxidizing agent concentration). This parameter control achieves the desired dispersion stability while minimizing harmful impurity formation compared to the channel process

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If low molecular weight polyamic acid is used to improve solubility, then resin content can be increased, but mechanical properties deteriorate

Engineering Contradiction:
Improveresin contentVSAvoidmechanical properties
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent changes the molecular weight parameter of the polyamic acid to an optimal range (5,000-20,000) that balances solubility and mechanical properties. This parameter optimization enables achieving high resin content (20-30 wt%) in the solution while maintaining sufficient mechanical strength in the final polyimide belt

Inventive Principle:
Principle #35Parameter changes

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 enables the production of semiconductive polyimide belts with stable electrical properties and high-quality image transfer, reducing production time and costs while ensuring safety and environmental adaptability by achieving uniform carbon black dispersion and controlled surface resistivity.

Implementation Method 1

a carbon black of 2% to 6% volatile content obtained by an oxidation treatment of carbon black produced by an oil furnace process

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP2072580B1Carbon-black-dispersed polyamic acid solution composition, and process for producing semiconductive polyimide resin belt therewith
Publication Date: 2014.04.02 UBE CORPORATION
  • EP2072580B1 patent drawingFigure 1(A)~2(C)
  • EP2072580B1 patent drawingFigure 3
  • EP2072580B1 patent drawing

AI summary

A carbon black-dispersed polyamic acid solution composition that utilizes carbon black excelling in safety and environmental adaptability and excels in the dispersion stability and fluidity of carbon black dispersed in polyamic acid solution, and that realizes high solid content and high carbon black content. Further, an intermediate transfer belt of polyimide, which produces a transfer image of high quality in a color image-forming apparatus, is provided with the use of the above polyamic acid solution composition. In particular, there is provided a carbon black-dispersed polyamic acid solution composition containing a polyamic acid solution obtained by reaction of approximately equimolar amounts of biphenyltetracarboxylic acid dianhydride and an aromatic diamine, and containing a carbon black of 2 to 6% volatile content produced by oil furnace process, wherein the solid content of the solution composition is 23 wt.% or more and wherein the carbon black content of the solid is in the range of 20 to 30 wt.%.