Injection-Molded RFID Inlay Structure for Heat-Stable Embedding
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Solution Overview
Problem
Conventional methods for attaching or embedding RFID tags in injection molded articles face issues such as air entrapment, off-gassing, deformation of the antenna due to heat, and adverse effects on the carrier substrate, leading to manufacturing complexity, cost, and potential device failure.
Innovation Solution
Multi-layered RFID devices with a stabilizing and heat-resistant structure, including adhesive layers and a substrate like high-density polyethylene, ensure the antenna's protection and stability during injection molding, allowing direct integration into the mold without adverse effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PET-based substrate is used in RFID tag for injection molding, then the substrate provides good mechanical properties and ease of manufacture, but the substrate shrinks and deforms under heat causing antenna deformation and device failure
Solution Approach 1:
The patent changes the material parameter of the substrate from PET-based material to polyolefin-based material (such as polyethylene or polypropylene). This parameter change makes the substrate resistant to thermal shrinkage and deformation during injection molding, while maintaining ease of manufacture through standard molding processes.
Solution Approach 2:
The patent uses composite material structures including the polyolefin-based substrate combined with conductive ink or foil for the antenna, and integrates these layers with the injection-molded article. This composite approach ensures both mechanical integrity and thermal stability during the molding process.
2Productivity
If RFID tag is embedded during injection molding, then manufacturing time is reduced compared to post-molding attachment, but air entrapment and off-gassing occur causing defects and weakening the article
Solution Approach 1:
The patent prepares the RFID tag components (substrate, antenna, adhesive layers) in advance as a pre-assembled unit before injection molding. This preliminary preparation allows the tag to be integrated into the mold cavity in a single step, maintaining productivity while reducing defects through proper material selection and layer configuration that prevents air entrapment.
Solution Approach 2:
The patent uses adhesive layers as intermediary materials between the substrate and the injection-molded article. These adhesive layers facilitate proper bonding while allowing gases to escape and preventing air entrapment, thus maintaining manufacturing precision without sacrificing productivity.
3Productivity
If thick adhesive layers are used to encapsulate antenna and IC, then manufacturing time is reduced, but thermal shrinking and expansion limit the antenna types and configurations that can be used
Solution Approach 1:
The patent changes the substrate material parameter to polyolefin-based materials that have low thermal shrinkage characteristics. This parameter change allows the use of various antenna types and configurations (different shapes, sizes, and conductive material patterns) without being constrained by excessive thermal deformation, thereby maintaining both productivity and adaptability.
4Reliability
If conventional attachment methods are used after injection molding, then the RFID tag can be properly attached, but additional adhesive application steps are required increasing manufacturing complexity
Solution Approach 1:
The patent merges the RFID tag attachment process with the injection molding process itself. The RFID tag is embedded into the article during molding, combining two separate operations (molding and tagging) into one. This eliminates the need for separate adhesive application steps and reduces manufacturing complexity while maintaining reliable attachment.
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 enables robust and functional RFID tags that survive the injection molding process without defects, maintaining operational integrity and reducing manufacturing complexity and costs.
Implementation Method 1
at least one adhesive layer is applied to the RFID inlay on one planar side of the substrate... so that the IC chip is covered or encapsulate by the adhesive
Implementation Method 2
the adhesive layer(s) has a thickness... measured perpendicular to the substrate surface
Implementation Method 3
during the injection molding process... under the application of heat
Implementation Method 4
embedding the RFID tag in the product
Implementation Method 5
the RFID inlay/tag attaches to the wall of the injection mold chamber by electrostatic charge
Data Source
AI summary
The invention relates to a Radio-Frequency Identification (RFID) device for an injection molded product comprising layers of different components to reduce thermal shrinkage or expansion and failure of the RFID inlay due to the high temperatures during injection molding. The introduced device allows for a thin build and a flat, smooth injection molded product.