Sheath-Core Polymer Sheets for Dyeability and Dielectric Strength
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Solution Overview
Problem
Existing sheet structures, such as papers, made from aramid fibers and fibrids, lack efficient dyeability and exhibit limited thermal stability and dielectric strength due to the use of single polymer homopolymers, which restricts their application in electrical insulation and other high-performance applications.
Innovation Solution
A sheet structure comprising a mixture of two polymers, where one polymer is derived from 5(6)-amino-2-(p-aminophenyl)benzimidazole and the other from metaphenylene diamine and isophthaloyl chloride, forming a sheath-core structure during coagulation, allowing for enhanced dyeability and improved thermal and dielectric properties by incorporating a less expensive polymer with a higher dielectric strength polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a homogeneous mixture of MPD-I and DAPBI copolymer is coagulated, then a sheath-core structure is formed that accepts acid dyes, but the manufacturing complexity increases
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer mixture, specifically using a homogeneous mixture containing MPD-I and DAPBI copolymer in specific ratios (e.g., 30-70 wt% MPD-I and 70-30 wt% DAPBI copolymer). This parameter change during coagulation leads to the formation of the sheath-core structure with acid dye acceptance properties.
Solution Approach 2:
The patent creates a composite material system by combining two different polymers (MPD-I and DAPBI copolymer) into a homogeneous mixture that forms a sheath-core structure during coagulation. The core contains primarily MPD-I while the sheath contains primarily DAPBI copolymer, creating a composite structure with combined properties.
2Reliability
If DAPBI copolymer is used to improve dielectric strength and thermal stability, then material cost increases, but using less expensive MPD-I reduces these properties
Solution Approach 1:
The patent applies local quality by concentrating the expensive DAPBI copolymer in the sheath region (outer layer) of the fiber or fibrid, while the core (inner region) contains the less expensive MPD-I. This spatial distribution optimizes material usage, providing dielectric strength and thermal stability where needed (in the sheath) while reducing overall material cost.
Solution Approach 2:
The patent creates a composite material system by combining two different polymers (MPD-I and DAPBI copolymer) into a homogeneous mixture that forms a sheath-core structure during coagulation. The core contains primarily MPD-I while the sheath contains primarily DAPBI copolymer, creating a composite structure with combined properties.
3Quantity of substance
If MPD-I homopolymer is used to reduce cost, then thermal stability decreases (L.O.I. of 30), but DAPBI copolymer provides improved thermal stability (L.O.I. of 45)
Solution Approach 1:
The patent applies local quality by concentrating the expensive DAPBI copolymer in the sheath region (outer layer) of the fiber or fibrid, while the core (inner region) contains the less expensive MPD-I. This spatial distribution optimizes material usage, providing dielectric strength and thermal stability where needed (in the sheath) while reducing overall material cost.
Solution Approach 2:
The patent makes the polymer mixture homogeneous before coagulation, allowing both MPD-I and DAPBI copolymer to contribute to multiple properties simultaneously. The resulting sheath-core structure provides both cost-effectiveness (from MPD-I core) and thermal stability (from DAPBI sheath), making the material multi-functional.
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 sheet structure achieves dyeability with acid dyes, maintains dielectric strength similar to DAPBI-based articles, and exhibits improved thermal stability, effectively combining the benefits of both polymers while reducing material costs.
Implementation Method 1
by coagulating a polymer solution containing a homogeneous mixture of MPD-I with a copolymer having charge characteristics opposite to MPD-I, made from the monomer (DAPBI), a shaped article can be made
Data Source
AI summary
This invention relates to a sheet comprising fibers and fibrids wherein either comprises a mixture of at least a first polymer and a second polymer;the first polymer derived from the reaction of one or more amine monomers and a plurality of acid monomers, wherein the one or more amine monomers includes at least 60 mole percent 5(6)-amino-2-(p-aminophenyl)benzimidazole, based on the total amount of amine monomers; andthe plurality of acid monomers include those having a structure ofCl—CO—Ar1—CO—Cl & Cl—CO—Ar2—CO—Clwherein Ar1 is an aromatic group having para-oriented linkages and Ar2 is an aromatic group having meta-oriented linkages, and wherein the plurality of acid monomers has at least 50 mole percent of the monomer containing aromatic group Ar2; andthe second polymer derived from the reaction of metaphenylene diamine and isophthaloyl chloride.