Multilayer Polyimide Film with Matte Silica and Carbon Black
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Solution Overview
Problem
The industry faces challenges in creating polyimide films that are matte in appearance, with deep, rich saturated colors, while also providing optical security and maintaining acceptable electrical and mechanical properties for use as coverlays in electronic applications.
Innovation Solution
A multilayer film comprising a first polyimide layer derived from at least 50 mole percent of an aromatic dianhydride and aromatic diamine, and a second polyimide layer with a silica matting agent and submicron carbon black, achieving an L* color less than 30 and a 60-degree gloss value less than 10, along with durability for handling and circuit processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the amount of matting agent is increased to achieve matte appearance, then the gloss value decreases, but the color becomes muted and L* color increases
Solution Approach 1:
The film is divided into two distinct layers: a first polyimide layer providing structural integrity and electrical properties, and a second polyimide layer containing matting agent and carbon black providing optical properties. This segmentation allows each layer to be optimized independently for its specific function.
Solution Approach 2:
The second polyimide layer is formulated as a composite material containing polyimide matrix, silica matting agent, and submicron carbon black. This composite structure enables simultaneous achievement of matte appearance (through silica) and deep saturated color (through carbon black) without the trade-off present in single-layer films.
2Illumination intensity
If more colorant is added to achieve deep saturated colors, then the L* color decreases, but the gloss value increases and matte appearance is lost
Solution Approach 1:
The film is divided into two distinct layers: a first polyimide layer providing structural integrity and electrical properties, and a second polyimide layer containing matting agent and carbon black providing optical properties. This segmentation allows each layer to be optimized independently for its specific function.
Solution Approach 2:
The second polyimide layer is formulated as a composite material containing polyimide matrix, silica matting agent, and submicron carbon black. This composite structure enables simultaneous achievement of matte appearance (through silica) and deep saturated color (through carbon black) without the trade-off present in single-layer films.
3Shape
If a single layer film is used to achieve matte appearance, then the gloss value decreases, but the color saturation and optical density are insufficient
Solution Approach 1:
The film is divided into two distinct layers: a first polyimide layer providing structural integrity and electrical properties, and a second polyimide layer containing matting agent and carbon black providing optical properties. This segmentation allows each layer to be optimized independently for its specific function.
Solution Approach 2:
The second polyimide layer is formulated as a composite material containing polyimide matrix, silica matting agent, and submicron carbon black. This composite structure enables simultaneous achievement of matte appearance (through silica) and deep saturated color (through carbon black) without the trade-off present in single-layer films.
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 multilayer film achieves the desired matte appearance with deep colors, optical security, and maintains electrical and mechanical properties, ensuring durability during handling and circuit processing.
Implementation Method 1
The effect of increased surface roughness from the matting agent is the dilution of the pigment color so that it appears lighter and less saturated. This is caused by the dilution of the diffuse reflectance (where pigment color is perceived) by the increased scatter of the specular reflectance (white light).
Data Source
AI summary
The present disclosure is directed to multilayer film having has an L* color less than 30 and a 60 degree gloss value less than 10. The multilayer film has a first polyimide layer and a second polyimide layer. The second polyimide layer has 45 to 67 wt % of a polyimide, greater than 14 wt % of a silica matting agent or a mixture of silica matting agent and at least one additional matting agent, and at least one submicron carbon black, wherein the total amount of the submicron carbon black and the polyimide is less than 85 wt % and greater than 45 wt %.