Multilayer Laser Marking Sheet with Segmented Polyester and Polycarbonate Layers
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Solution Overview
Problem
Existing laser marking multilayer sheets for identification cards, such as electronic passports and IC cards, face challenges in achieving clear and high-contrast images within narrow dimensions, while also ensuring thermal adhesiveness, heat resistance, and preventing falsification and forging.
Innovation Solution
A multilayer sheet configuration comprising a transparent laser marking sheet with a noncrystalline aromatic polyester skin layer and a polycarbonate core layer, and a colored laser marking sheet with a polycarbonate core layer and an inorganic pigment, both formed by coextrusion, providing excellent contrast, thermal adhesiveness, and resistance to heat and bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser marking multilayer sheet uses a simple single-layer or two-layer structure, then the manufacturing process is simple, but the contrast between base area and print area is insufficient and images cannot be clearly displayed within narrow dimensions
Solution Approach 1:
The patent divides the multilayer sheet into distinct functional layers: a base layer (transparent or translucent) and a marking layer (colored or black). This segmentation allows each layer to perform its specific function - the base layer provides structural support and optical properties, while the marking layer provides high-contrast laser marking capability. The clear demarcation between layers enables precise control over image quality and contrast within narrow dimensions.
Solution Approach 2:
The patent applies different material properties to different layers to optimize local functions. The base layer uses transparent or translucent materials for optimal light transmission and structural integrity, while the marking layer uses colored or black materials with specific laser absorption characteristics for high-contrast marking. This local differentiation of material properties ensures that each region of the multilayer sheet performs its intended function with maximum effectiveness.
2Reliability
If the multilayer sheet uses materials with high thermal adhesiveness for bonding layers, then the layers bond well, but the heat resistance during laser marking and overall durability may be compromised
Solution Approach 1:
The patent carefully controls the thermal properties of materials and processing parameters to achieve optimal performance. The base layer and marking layer materials are selected with specific glass transition temperatures and melting points that allow strong thermal bonding during manufacturing while maintaining heat resistance during subsequent laser marking operations. The bonding process parameters (temperature, time, pressure) are precisely controlled to ensure adequate adhesion without compromising the thermal stability of the final product.
3Manufacturing precision
If the multilayer sheet is designed with optimized layer thicknesses for high contrast, then clear images are achieved, but the structural strength and durability may be reduced
Solution Approach 1:
The patent optimizes the thickness parameters of each layer to achieve the desired balance between image contrast and structural strength. The base layer is designed with sufficient thickness to provide structural support and durability, while the marking layer thickness is carefully controlled to ensure high-contrast laser marking without compromising overall sheet strength. These thickness parameters are precisely engineered to meet both optical and mechanical performance requirements.
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 clear and high-contrast characters and images, prevents falsification and forging, and ensures excellent thermal adhesiveness and heat resistance, making it suitable for electronic passports and plastic cards.
Implementation Method 1
an inner layer formed of a thermoplastic resin composition that includes (b-1) based on 100 parts by weight of a thermoplastic resin, (b-2) 0.01 to 5 parts by weight of a laser beam energy absorber
Data Source
AI summary
A laser marking multilayer sheet includes a multilayer sheet A, and a multilayer sheet B that is stacked under the multilayer sheet A. The multilayer sheet A is a transparent laser marking multilayer sheet. A skin layer that forms each outermost layer of the multilayer sheet A is formed of a noncrystalline aromatic polyester resin composition, and a core layer of the multilayer sheet A is formed of a polycarbonate resin composition. The multilayer sheet B is a colored laser marking multilayer sheet. A skin layer that forms each outermost layer of the multilayer sheet B is formed of a noncrystalline aromatic polyester resin composition, and a core layer of the multilayer sheet B is formed of a polycarbonate resin composition.