Aramid Insulating Paper with Fibrid Pulp Short-cut Composition
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Solution Overview
Problem
Existing electrical insulating papers face challenges in achieving a balance between high dielectric strength, tensile index, and ease of manufacture, particularly with high fibrid content papers being difficult to produce and having insufficient tear strength for certain applications.
Innovation Solution
A electrical insulating paper composition comprising 40-80 wt.% aramid fibrid, 10-50 wt.% aramid pulp, and 10-50 wt.% aramid short-cut, with preferred para-aramid components and specific processing methods such as calendering at elevated temperatures to enhance properties and manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high fibrid content (40-100 wt.%) is used to increase dielectric strength, then dielectric strength is improved, but manufacturing difficulty increases and tear strength becomes insufficient
Solution Approach 1:
The patent applies composite materials by combining three distinct aramid components (fibrid, pulp, and short-cut) in specific proportions. The fibrid component (40-80 wt.%) provides dielectric strength, while the pulp (10-50 wt.%) and short-cut (10-50 wt.%) components improve manufacturability and tear strength. This composite approach resolves the contradiction by integrating materials with complementary properties to achieve both high dielectric strength and ease of manufacture simultaneously.
2Reliability
If 100% aramid fibrid is used to maximize dielectric strength, then dielectric strength is improved, but tear strength becomes insufficient for certain applications
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different components within the paper structure. The fibrid component (40-80 wt.%) is optimized for dielectric strength, while the pulp (10-50 wt.%) and short-cut (10-50 wt.%) components are optimized for mechanical strength and tear resistance. This functional differentiation resolves the contradiction by ensuring that no single component must simultaneously excel at both dielectric strength and tear strength.
3Quantity of substance
If high porosity is used to improve certain paper properties, then porosity is improved, but electric resistance decreases making it unsuitable for electrical insulating paper
Solution Approach 1:
The patent applies parameter changes by carefully controlling the physical and chemical parameters of the aramid components and their arrangement in the paper structure. By optimizing the Schopper Riegler value of the pulp (15-85) and the size distribution of fibrid and short-cut components, the patent achieves a balanced porosity that maintains adequate electric resistance while allowing for proper manufacturing and performance characteristics.
Data Source
AI summary
The present invention pertains to an electrical insulating paper comprising 40-80 wt.% of aramid fibrid, 10-50 wt.% of aramid pulp, and 10-50 wt.% of aramid short-cut, the aramid pulp being para-aramid pulp with a length of 0.5-6 mm and a Schopper Riegler of 15-85. Preferably, the fibrid is para-aramid fibrid and/or the shortcut is para-aramid shortcut. More preferably, the fibrid is para-aramid fibrid, and the shortcut is para-aramid shortcut. It has been found that a paper meeting the above requirements shows an increased value for the product of the dielectric strength (expressed in kV/mm) and the tensile index (expressed in Nm/g), as compared to systems comprising only two of the cited components, or less than 40 wt.% of aramid fibrid. The paper is relatively easy to manufacture, and has good tear strength. The paper is particularly suitable for use in insulated conductors.