Low Dielectric Resin Composition for High-Frequency PCBs
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Solution Overview
Problem
Liquid crystal polymers face challenges in high-frequency applications due to high dielectric loss and poor melt processability, leading to transmission loss issues in communication devices, and their anisotropy makes pellet production and film formation difficult.
Innovation Solution
A low dielectric resin composition combining liquid crystal polymer and graft-modified polyolefin with a polar group, which reduces dielectric properties and improves melt processability, forming a sea-island structure for enhanced heat resistance and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If liquid crystal polymer is used as a low dielectric material, then dielectric loss is reduced, but melt processability deteriorates due to anisotropy
Solution Approach 1:
The patent combines liquid crystal polymer (providing low dielectric loss) with graft-modified polyolefin (providing good melt processability) to create a composite resin composition. This composite approach allows the material to simultaneously achieve low dielectric properties for high-frequency applications and adequate processability for manufacturing, resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The patent modifies the polyolefin component by introducing polar groups through grafting, which changes the material's dielectric parameters. This modification allows the polyolefin to contribute to low dielectric loss while maintaining its inherent processability advantages, thereby balancing the trade-off between dielectric performance and manufacturability.
2Productivity
If liquid crystal polymer is subjected to extrusion process, then film formation is attempted, but film quality deteriorates due to melt viscosity reduction and orientation
Solution Approach 1:
By combining liquid crystal polymer with graft-modified polyolefin, the composite resin achieves a balance between the LCP's tendency to orient and the modified polyolefin's ability to maintain melt strength. This composite structure prevents excessive orientation during extrusion, thereby maintaining film quality while enabling productive film formation.
Solution Approach 2:
The graft-modified polyolefin acts as an intermediary component that mediates between the liquid crystal polymer's anisotropic behavior and the extrusion process requirements. It provides a matrix that constrains excessive orientation while allowing the LCP to contribute its low dielectric properties, thus ensuring both productivity and manufacturing precision.
3Productivity
If liquid crystal polymer strand is cut into pellets, then pellet production is attempted, but pellet quality deteriorates due to anisotropy causing whiskers and unevenness
Solution Approach 1:
The composite resin composition combines liquid crystal polymer with graft-modified polyolefin to create a material that can be pelletized effectively. The modified polyolefin component provides a matrix that maintains structural integrity during cutting, preventing the formation of whiskers and ensuring uniform pellet shapes, thus achieving both high productivity and manufacturing precision.
Data Source
AI summary
The present disclosure provides a low dielectric resin composition having good melt processability and excellent low dielectric characteristics in a high frequency band as compared to low dielectric materials such as liquid crystal polymers. A molded article and a film, each of which is formed from the low dielectric resin composition, a multilayer film obtained by superposing a metal foil on at least one main surface of the film, and a flexible printed wiring board which includes the film are also provided. The present disclosure includes, as a low dielectric resin composition, a resin composition which contains (A) a liquid crystal polymer and (B) a graft-modified polyolefin having a polar group. The low dielectric resin composition has a dielectric constant of 2.80 or less at a frequency of 10 GHz and a dielectric loss tangent of 0.0025 or less at a frequency of 10 GHz.