Polycarbonate IC Sheet Bonding Through Nonwoven Fiber Integration
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Solution Overview
Problem
Existing IC sheets using polycarbonate cover sheets for increased strength suffer from peeling issues during integration due to poor adhesiveness, leading to reduced productivity and limited thickness reduction, and bulkiness in applications like passports.
Innovation Solution
Integrate polycarbonate cover sheets with a nonwoven fabric support sheet by solidifying the polycarbonate resin between the fibers of the nonwoven fabric, eliminating the need for adhesives and ensuring firm bonding without increasing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycarbonate is used as the material of the cover sheet to improve mechanical strength, then the strength is sufficient even with thin thickness, but the adhesiveness to the inlet deteriorates causing peeling during hot pressing
Solution Approach 1:
A resin layer is introduced as an intermediary between the polycarbonate cover sheet and the inlet. This resin layer has high adhesiveness to both the polycarbonate and the inlet materials, serving as a bonding mediator that prevents peeling while allowing the cover sheet to maintain its thin profile and high mechanical strength
Solution Approach 2:
The cover sheet structure is made composite by combining polycarbonate with a resin layer. This composite structure leverages the high mechanical strength of polycarbonate and the high adhesiveness of the resin, achieving both strength and bonding reliability simultaneously
2Reliability
If an adhesive is applied to improve the bonding between the inlet and cover sheet, then the peeling problem is solved, but the manufacturing process complexity increases and productivity decreases
Solution Approach 1:
The resin layer is integrated into the hot pressing process itself, combining the bonding function with the existing manufacturing step. The resin is applied to the inlet before hot pressing, and the heat and pressure of the hot pressing process simultaneously bond the resin to both the inlet and cover sheet, eliminating the need for separate adhesive application steps
Solution Approach 2:
The resin layer performs multiple functions automatically during the hot pressing process: it bonds the inlet to the cover sheet, and the hot pressing conditions (heat and pressure) that are already applied for forming the IC sheet also activate and cure the resin, eliminating the need for additional bonding process steps
3Reliability
If an adhesive layer is formed to improve bonding, then the peeling is prevented, but the thickness dimension of the IC sheet increases
Solution Approach 1:
The resin layer is designed with controlled thickness parameters (0.01-0.05 mm) and the hot pressing conditions (temperature and pressure) are optimized to achieve sufficient bonding strength with minimal material. This parameter optimization allows the bonding function to be achieved while keeping the added thickness to a minimum, maintaining the thin profile of the IC sheet
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 solution provides a securely integrated IC sheet with enhanced mechanical strength and impact resistance, preventing peeling and allowing for thinner designs without compromising productivity, thus enhancing security and designability.
Implementation Method 1
polycarbonate resin constituting the cover sheets 3 and 4 is solidified in a state of entering between fibers of the nonwoven fabric of the support sheet 10
Implementation Method 2
The inlet and the cover sheets are integrated by hot pressing in a state where they are stacked
Data Source
AI summary
To reliably prevent cover sheets from peeling off from an inlet without lowering productivity even in a case where polycarbonate is selected as material of the cover sheets in an IC sheet including the inlet and the cover sheets disposed on and under the inlet. An IC sheet of the present invention includes: an inlet including an IC chip, an antenna that is connected to the IC chip, and a support sheet that includes a nonwoven fabric and holds the IC chip and the antenna; and cover sheets that include polycarbonate and are disposed under and on the inlet, respectively. Polycarbonate resin constituting the cover sheets is solidified in a state of entering between fibers of the nonwoven fabric of the support sheet, so that the cover sheets and the support sheet are integrated.