Porous Polyimide Article Thickness and Dielectric Control
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Solution Overview
Problem
Porous polyimide shaped articles with thicknesses less than 550 μm exhibit low tensile strength and in-plane variation in relative dielectric constant due to inconsistent pore size distribution.
Innovation Solution
A porous polyimide shaped article with a thickness between 550 μm and 3,000 μm, featuring a relative dielectric constant of 1.8 or less and a dielectric loss tangent of 0.01 or less at 1 MHz, is manufactured using a method involving a polyimide precursor solution and resin particles, where the resin particles are removed to control pore size distribution, thereby improving tensile strength and reducing in-plane variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of porous polyimide shaped article is reduced to less than 550 μm, then the weight and size are reduced, but the tensile strength becomes low
Solution Approach 1:
The invention changes the pore size distribution parameter (controlling D84/D16 ratio to 1.2-1.6) and thickness parameter (550-3000 μm) to simultaneously achieve reduced weight and maintained tensile strength. By optimizing these parameters together rather than independently, the invention resolves the contradiction between lightweight design and mechanical strength.
2Quantity of substance
If the pore size distribution is inconsistent, then the porosity and lightweight properties are improved, but the in-plane variation in relative dielectric constant increases
Solution Approach 1:
The invention optimizes the pore size distribution parameter (D84/D16 ratio between 1.2-1.6) to simultaneously achieve high porosity and uniform dielectric properties. By controlling this specific parameter range, the invention resolves the contradiction between maximizing porosity for lightweight properties and maintaining manufacturing precision for electrical performance uniformity.
Data Source
AI summary
A porous polyimide shaped article has a thickness in a range from 550 μm to 3,000 μm and has a relative dielectric constant of 1.8 or less and a dielectric loss tangent of 0.01 or less at 1 MHz. The porous polyimide shaped article satisfies the following formula:1.2≤A≤1.6wherein A represents a square root of a ratio of a pore size D84 where a cumulative percentage by number of pores from smaller sizes is 84% to a pore size D16 where the cumulative percentage by number of the pores from smaller sizes is 16% ((D84/D16)1/2) in a pore size distribution measured by mercury intrusion porosimetry.