Polycarbonate Resin Composition for Laser-Marking Coloring Properties
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Solution Overview
Problem
Conventional resin films for laser marking lack good color tones and exhibit insufficient brightness, with a strong yellow hue and a slightly colored surface.
Innovation Solution
A resin composition containing a thermoplastic resin with polycarbonate and a black pigment of specific primary particle diameter (40-80 nm) and concentration (20-40 mass ppm), which enhances color tones and laser-marking properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional resin films are used for laser marking, then the basic function of laser marking is achieved, but the color tones are poor with insufficient brightness and strong yellow hue
Solution Approach 1:
The patent applies parameter changes by precisely controlling the primary particle diameter of the black pigment to 40-80 nm and adjusting its concentration to 20-40 mass ppm. These specific parameter ranges optimize both the laser absorption properties and the color tone, eliminating the yellow hue while maintaining sufficient brightness for high-quality laser marking.
Solution Approach 2:
The patent uses a composite material approach by combining polycarbonate resin with specifically sized black pigment particles. This composite structure allows the material to exhibit both the desired optical properties for laser marking and the aesthetic color tones, resolving the contradiction between functionality and appearance.
2Reliability
If black pigment is added to improve laser marking properties, then laser coloring capability is enhanced, but the surface appears slightly colored and brightness is reduced
Solution Approach 1:
The patent resolves this contradiction by changing the particle size parameter of the black pigment to 40-80 nm, which is large enough to provide sufficient laser absorption for reliable marking but small enough to avoid excessive light scattering that would reduce surface brightness. The concentration is also optimized to 20-40 mass ppm to balance these effects.
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 resin composition achieves excellent color tones and improved laser marking properties, suitable for security cards, ID cards, and e-passports, with a light absorption rate of 10% or more at 1064 nm and specific color tone differences.
Implementation Method 1
the light absorption rate A % at a wavelength of 1064 nm defined by formula (a) below is 10% or more: 100−(T(%)+R(%))=A(%)
Data Source
AI summary
The present invention realizes a card-use resin composition that exhibits beautiful colors and that has high laser-marking coloring properties, a card-use resin sheet formed with the card-use resin composition, and a card. The above problem has been solved by a card-use resin composition containing a laser coloring agent and a thermoplastic resin, wherein the thermoplastic resin contains a polycarbonate resin, and the laser coloring agent contains at least one type of black pigment, the primary particle diameter of the black pigment being 40 to 80 nm, and the amount of the black pigment with respect to the entire mass of the card-use resin composition being 20 to 40 mass ppm.