Laser-Markable Polymer Composition for Dark Backgrounds

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Solution Overview

Problem

Existing polymer compositions for dark-colored materials have a limited processing window for laser marking, resulting in a small range of acceptable laser parameters for achieving good contrast between the dark background and light markings, making them less versatile and sensitive to variations in laser settings.

Innovation Solution

Incorporating a laser marking additive comprising a polymer of an acrylate monomer or a mixture of this additive with metal sulfates such as Na, K, Mg, Ca, Ba, Zr, Zn, Al, or Si into the polymer composition, which allows for a wider range of laser parameters to achieve good contrast between a dark background and light laser marks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional polymer compositions with colorants are used for laser marking on dark backgrounds, then light markings can be obtained, but the processing window for laser parameters is very small and contrast strongly decreases with parameter variations

Engineering Contradiction:

Improvecontrast between marking and backgroundVSAvoidrange of acceptable laser parameters

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The invention uses a composite laser marking additive comprising a polymer of an acrylate monomer combined with metal sulfates (such as barium sulfate, zinc sulfate, calcium sulfate). This composite material absorbs laser energy more effectively and consistently across varying laser parameters, enabling high contrast markings on dark backgrounds while significantly expanding the acceptable processing window for laser frequency, power, and speed settings.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical composition parameters of the laser marking additive by selecting specific acrylate monomers (with different chain lengths and functional groups) and metal sulfates. This parameter optimization allows the additive to maintain effective laser absorption across a broader range of laser operating conditions, thereby expanding the processing window while preserving marking contrast.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If conventional laser marking additives are used, then markings can be applied, but the choice of colorant is critical and limits the variety of usable colorants

Engineering Contradiction:

Improvechoice of colorantVSAvoidlight laser markability on dark background

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The composite laser marking additive acts as an intermediary substance that decouples the colorant selection from the laser marking performance. The additive's strong and broad laser absorption characteristics enable it to function effectively regardless of the specific colorant used, allowing manufacturers to choose colorants based on aesthetic requirements without compromising marking reliability on dark backgrounds.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If laser parameters are varied from optimum settings, then processing flexibility increases, but contrast value strongly decreases with conventional polymer compositions

Engineering Contradiction:

Improveprocessing flexibilityVSAvoidcontrast value

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

By optimizing the chemical composition parameters of the laser marking additive (selecting specific acrylate monomers and metal sulfates in appropriate ratios), the invention creates a material that maintains effective laser absorption across a broader range of laser operating conditions. This allows processing flexibility to increase while contrast value remains stable, resolving the trade-off between ease of operation and manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

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

This solution enables light laser marks to be applied on dark backgrounds with improved contrast over a larger range of laser parameters, reducing the criticality of colorant selection and allowing for a variety of colorants to be used without impairing markability, thus expanding the processing window for laser marking.

Implementation Method 1

the absorption of laser energy by using a combination of organic colorants with inorganic pigments

Methodology Applied

Scientific EffectLaser absorption: Absorption (EM radiation)

Implementation Method 2

a process for applying a light laser mark onto a dark background of such article

Methodology Applied

Scientific EffectLaser marking: Laser Ablation

Data Source

PatentEP1989057B1Dark colored, laser-markable polymer composition

Publication Date: 2012.04.11 MITSUBISHI CHEM EURO

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AI summary

The invention relates to a polymer composition comprising a thermoplastic polymer and at least one colorant, wherein the composition further comprises from 0.1 to 15 wt.%, relative to the total weight of the composition, of a laser marking additive being or comprising a polymer of an acrylate monomer or a metal sulfate whereby the metal is Na, K, Mg, Ca, Ba, Zr, Zn, Al or Si, or wherein the composition further comprises from 0.1 to 15 wt.% , relative to the total weight of the composition, of a mixture comprising at least two of said laser marking additives.