Laser-Marking Polymer Composition for Dark, Sharp Polyamide Labels

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Solution Overview

Problem

Existing laser inscription methods for polyamide and polyester plastics, especially those containing flame retardants, fail to produce durable, high-contrast markings with sharp edges, and often result in foaming and odorous by-products.

Innovation Solution

A polymer composition comprising a polyamide or polyester carrier matrix with embedded sulfur-containing polymer particles, including titanium oxide and antimony-doped tin oxide composite pigments, enhances laser inscription performance by providing a synergistic absorption of laser radiation, resulting in durable, high-contrast markings with sharp edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional laser inscription methods are used on polyamide and polyester plastics, then the process is simple and contactless, but the markings produced are pale, lack high contrast, and have poor durability

Engineering Contradiction:
Improvemarking contrastVSAvoidlaser additive effectiveness
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent uses a composite laser additive system combining sulfur-containing polymer particles (0.1-5 μm) with metal oxide particles (titanium dioxide, antimony trioxide, tin oxide) embedded in the plastic matrix. This composite approach creates synergistic effects where the sulfur-containing polymer absorbs laser radiation and converts it to heat, while the metal oxide particles enhance light absorption and prevent foaming, together producing dark, high-contrast markings that meet market requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the plastic by incorporating specific amounts of sulfur-containing polymers (0.01-5 wt%) and metal oxide particles (0.1-10 wt%). This parameter change transforms the laser response characteristics of the plastic, enabling dark markings with high contrast and sharp edges on polyamide and polyester materials that previously produced only pale marks.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If flame retardants are added to polyester plastics, then fire safety is improved, but laser inscription performance deteriorates due to strong foaming

Engineering Contradiction:
Improvefire safetyVSAvoidmarking darkness
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent introduces sulfur-containing polymer particles as an intermediary substance that mediates between the laser radiation and the plastic matrix containing flame retardants. These particles absorb laser energy and convert it to localized heat, enabling dark markings without triggering the foaming reaction that normally occurs with flame retardant-containing plastics under direct laser irradiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful foaming effect of flame retardants under laser irradiation into a beneficial process by using sulfur-containing polymers that control and direct the thermal reaction. The sulfur-containing polymer undergoes controlled thermal decomposition that produces dark carbonized markings while suppressing uncontrolled foaming, thereby maintaining both fire safety and marking quality.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Illumination intensity

If polyamide plastics are laser marked without additives, then the process is simple, but the markings are virtually impossible to achieve with good contrast

Engineering Contradiction:
Improvemarking visibilityVSAvoidadditive composition
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent changes the compositional parameters of polyamide plastic by incorporating sulfur-containing polymer particles (0.01-5 wt%) and metal oxide particles (0.1-10 wt%). This parameter modification enables the polyamide to absorb laser radiation effectively and produce dark, high-contrast markings, transforming it from a non-laser-markable material to one that meets market requirements for visibility and durability.

Inventive Principle:
Principle #35Parameter changes

4Illumination intensity

If existing laser additives are used, then some marking capability is achieved, but the markings lack sharp edges and produce odorous by-products

Engineering Contradiction:
Improvemarking contrastVSAvoidodorous by-products
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent employs a composite additive system where sulfur-containing polymer particles work synergistically with metal oxide particles (titanium dioxide, antimony trioxide, tin oxide). This composite approach produces dark markings with sharp edges while the metal oxide particles suppress the formation of odorous by-products by controlling the thermal decomposition pathway of the sulfur-containing polymer, eliminating the harmful effects associated with conventional laser additives.

Inventive Principle:
Principle #40Composite materials

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 polymer composition achieves improved laser inscription with high contrast and edge sharpness, minimizing odors and meeting market requirements for dark, durable markings in polyamide and polyester plastics.

Implementation Method 1

the polymer particles consist of a sulfur-containing polymer matrix in which particulate oxides of titanium or particulate titanates, which may be doped in each case, and composite pigments are homogeneously embedded

Methodology Applied
Scientific EffectLaser radiation absorption: Absorption (EM radiation)

Implementation Method 2

providing a synergistic absorption of laser radiation, resulting in durable, high-contrast markings with sharp edges

Methodology Applied
Scientific EffectPhotothermal conversion:

Implementation Method 3

the energy thereby released to the plastic leading to foaming or carbonisation of the plastic

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 4

leading to foaming or carbonisation of the plastic

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentUS20250388750A1Polymer composition for laser marking
Publication Date: 2025.12.25 SUSONITY COMMERCIAL GMBH

AI summary

The invention relates to a polymer composition comprising a polyamide or polyester carrier polymer matrix in which special polymer particles are embedded, to a process for the preparation of this polymer composition, to the use thereof as laser inscription additive or laser welding additive in organic polymer compositions, and to a laser-inscribable or laser-weldable organic polymer composition comprising this polymer composition.