Polyamide Carbon Black Laser Markable Materials

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Solution Overview

Problem

Conventional polycarbonate-based laser markable materials for identification cards and security documents exhibit poor resistance to industrial and daily chemicals, leading to cracking and reduced lifespan when exposed to organic solvents and creams/lotions.

Innovation Solution

A laser markable polymer composite comprising a polyamide matrix, specifically linear or cycloaliphatic polyamides, combined with carbon black as a laser-sensitive additive, providing improved chemical resistance and maintaining transparency and laser marking quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polycarbonate is used as the matrix for laser markable materials, then laser marking capability is achieved, but chemical resistance deteriorates leading to cracking and reduced lifetime

Engineering Contradiction:
Improvechemical resistanceVSAvoidlifetime
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the material parameter from polycarbonate to polyamide, fundamentally altering the chemical resistance properties while maintaining laser markability through the carbon black additive system

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining polyamide matrix with carbon black particles, where the composite provides both the chemical resistance of polyamide and the laser absorption capability of carbon black

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If carbon black is added to achieve laser sensitivity, then laser marking quality is improved, but material transparency is reduced

Engineering Contradiction:
Improvelaser marking sharpnessVSAvoidtransparency
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent applies local quality by concentrating carbon black particles in specific regions or at controlled concentrations, providing laser sensitivity only where needed while maintaining overall material transparency

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent optimizes the concentration parameter of carbon black particles to achieve the minimum effective amount for laser marking while preserving material transparency, representing a precise parameter optimization

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

The polyamide-carbon black composite offers enhanced chemical resistance, preventing damage from industrial and daily chemicals, while maintaining the desired laser marking sharpness and resolution, potentially reducing the need for additional protective layers.

Implementation Method 1

carbon black as a laser-sensitive additive

Methodology Applied
Scientific EffectLaser absorption: Absorption (EM radiation)

Data Source

PatentEP3589697B1Laser markable materials comprising a polyamide component and carbon black
Publication Date: 2024.01.03 EVONIK OPERATIONS GMBH
  • EP3589697B1 patent drawingFigure 1~8
  • EP3589697B1 patent drawingFigure 9~16
  • EP3589697B1 patent drawingFigure 17~24

AI summary

The present invention relates to a laser markable polymer composite, comprising (a) a polyamide component as the matrix, and (b) carbon black as a laser-sensitive additive, wherein the polyamide component consists of based on the total weight thereof at least 50 wt% a polyamide selected from a linear aliphatic polyamide (a1) or (a2), a cycloaliphatic polyamide (a3), a semi-aromatic polyamide (a4) or (a5) and the compound thereof as well as the copolymer thereof, the carbon black is present in an amount of 50-300 ppm, based on the total weight of the polymer composite. The present invention results in better chemical resistance than conventional polycarbonate as the matrix in addition to desired quality (that is to say sharpness and resolution) of laser marking. The present invention also relates to the use of, and the moulded article made of the laser markable polymer composite as well as a layered structure comprising at least one layer made of the laser markable polymer composite and a security and/or valuable document comprising the layered structure.