Laminated Conductive Sheet for Electronic Packaging
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Solution Overview
Problem
Conventional electrically conductive sheets used for packaging electronic components face challenges in mechanical strength, moldability, and formation of burrs and sink marks during high-speed packaging and mounting, especially at lower temperatures and in miniaturized components, which can lead to contamination and protection issues.
Innovation Solution
A laminated electrically conductive sheet comprising a substrate layer with 21-87% polycarbonate resin, 7-68% polyalkylene terephthalate resin, and 3-30% carbon black, and a surface layer with 19-86% polycarbonate resin, 6-67% polyalkylene terephthalate resin, and 5-35% carbon black, produced by co-extrusion methods, providing enhanced mechanical strength and reduced burr formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon black is dispersed in thermoplastic resin to create electrically conductive sheet, then electrical conductivity and cost-effectiveness are improved, but mechanical strength and moldability deteriorate
Solution Approach 1:
The patent uses a composite material system consisting of polycarbonate resin as the base polymer and carbon black as the conductive filler. This composite structure allows the material to simultaneously exhibit mechanical properties from the polycarbonate and electrical conductivity from the carbon black dispersion, resolving the contradiction between mechanical strength and electrical conductivity
Solution Approach 2:
The patent optimizes the carbon black content parameter within a specific range (5-35 mass%) to balance electrical conductivity and mechanical strength. By controlling this parameter, the material achieves sufficient conductivity while maintaining adequate mechanical properties for high-speed packaging applications
2Ease of manufacture
If conventional carrier tape is used for packaging, then basic packaging function is achieved, but burrs and sink marks form at slit portions during blanking and slitting
Solution Approach 1:
The patent modifies the resin composition parameters by incorporating specific ratios of polycarbonate and polyalkylene terephthalate, which changes the material's processing characteristics. This parameter change reduces burr and sink mark formation during blanking and slitting operations, improving slit edge quality while maintaining packaging functionality
Solution Approach 2:
The patent creates a surface layer with optimized carbon black content (5-35 mass%) that is different from the substrate layer (3-30 mass%). This local quality difference in the surface layer specifically addresses the slit edge quality issue at the cutting surfaces, while the substrate maintains overall structural integrity
3Manufacturing precision
If sheet width is reduced and components are miniaturized for precise packaging, then packaging precision is improved, but mechanical strength and moldability become insufficient for high-speed mounting
Solution Approach 1:
The patent employs a composite material system with polycarbonate resin providing mechanical strength and polyalkylene terephthalate enhancing processability. This composite structure enables miniaturized sheets to maintain sufficient mechanical strength for high-speed mounting while achieving the precision required for small electronic components
Solution Approach 2:
The patent optimizes the resin composition parameters, specifically the ratio of polycarbonate to polyalkylene terephthalate, to enhance mechanical strength in miniaturized applications. This parameter optimization allows the material to maintain adequate strength even when sheet dimensions are reduced for precise packaging of small components
4Use of energy by stationary object
If molding temperature is reduced for various molding methods, then energy consumption and cycle time are improved, but mechanical strength and moldability decrease
Solution Approach 1:
The patent modifies the resin composition parameters by incorporating polyalkylene terephthalate, which has different thermal and mechanical properties compared to pure polycarbonate. This parameter change allows the material to be molded at lower temperatures while maintaining adequate mechanical strength and moldability, reducing energy consumption without sacrificing performance
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 offers excellent mechanical strength for high-speed packaging and mounting, can be molded in a wide temperature range, and significantly reduces burr and sink mark formation, ensuring precise and contamination-free packaging of electronic components.
Implementation Method 1
a sheet which comprises a substrate layer containing from 21 to 87 mass % of a polycarbonate resin, from 7 to 68 mass % of a polyalkylene terephthalate resin
Implementation Method 2
a sheet which comprises a substrate layer containing from 21 to 87 mass % of a polycarbonate resin, from 7 to 68 mass % of a polyalkylene terephthalate resin
Implementation Method 3
carbon black, capable of providing a uniform and stable surface resistivity
Implementation Method 4
laminated on one side or both sides of the substrate layer by extrusion, co-extrusion or extrusion coating
Data Source
AI summary
A sheet which has a substrate layer containing from 21 to 87 mass % of a polycarbonate resin, from 7 to 68 mass % of a polyalkylene terephthalate resin and from 3 to 30 mass % of carbon black, and a surface layer containing from 19 to 86 mass % of a polycarbonate resin, from 6 to 67 mass % of a polyalkylene terephthalate resin and from 5 to 35 mass % of carbon black, laminated on one side or both sides of the substrate layer by extrusion, co-extrusion or extrusion coating, where the sheet has a burr incidence ratio of at most 4%, and a carrier tape using the sheet.