Core-Shell Metal Oxide Additives for Laser Marking

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Solution Overview

Problem

Existing methods for incorporating metal oxides and mixed-metal oxides into plastics for laser marking and other applications often result in thermal oxidative degradation, compromising the mechanical properties and longevity of plastic articles.

Innovation Solution

A core-shell composite material is developed, where a metal oxide or mixed-metal oxide core is encapsulated with an inorganic shell, which is then integrated into plastic compositions to minimize thermal oxidative degradation and enhance laser direct structuring capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If metal oxides or mixed-metal oxides are incorporated into plastic compositions for laser marking and other applications, then laser direct structuring capability and desired functionality are improved, but thermal oxidative degradation occurs which compromises mechanical properties

Engineering Contradiction:
Improvelaser direct structuring capabilityVSAvoidmechanical properties
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

An inorganic shell (such as silica or alumina) is introduced as an intermediary layer between the metal oxide core and the plastic matrix. This shell acts as a protective barrier that prevents direct contact between the metal oxide and the plastic, thereby eliminating the catalytic effect that causes thermal oxidative degradation while still allowing the metal oxide to function as a laser marker or additive

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses a core-shell composite structure where a metal oxide core is coated with an inorganic shell material. This composite particle combines the desirable laser-marking properties of the metal oxide with the protective and stabilizing characteristics of the inorganic shell, creating a material that maintains both functionality and mechanical integrity during thermal processing

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If metal oxides are used as additives in plastic formulations, then coloration and laser marking properties are achieved, but thermal oxidative degradation accelerates during processing

Engineering Contradiction:
Improvecoloration and laser marking propertiesVSAvoidthermal oxidative degradation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The inorganic shell serves as a mediator that physically separates the metal oxide from the plastic matrix during compounding and processing. This intermediary layer prevents the metal oxide from catalyzing oxidative reactions in the plastic while allowing the additive to maintain its coloration and laser-marking functions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The inorganic shell is applied to the metal oxide core before incorporation into the plastic formulation. This preliminary protective action prevents the metal oxide from causing thermal oxidative degradation during subsequent high-temperature processing steps such as extrusion and molding

Inventive Principle:
Principle #9Preliminary anti-action

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 core-shell approach effectively mitigates thermal oxidative damage, maintaining the mechanical integrity and functionality of plastics while enabling effective laser direct structuring and marking without detrimental effects on the plastic's properties.

Implementation Method 1

a plastic article comprising a plastic resin and a core-shell composite material is subjected to a laser beam thus creating at least one laser-etched area wherein thus metal atoms of the core are activated and exposed

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3129435B1Core-shell composite inorganic metal oxides and method of preparation for prevention of thermal oxidative degradation in polymer and resin compositions
Publication Date: 2019.08.21 SHEPHERD COLOR CO
  • EP3129435B1 patent drawingFigure 1

AI summary

This invention relates to products of aqueous and other chemical synthetic routes for encapsulation of a core material with an inorganic shell and finished compositions of a core- shell particulate material for application in thermoplastic, thermoset, and coatings resins prior to compounding or application or subsequent thermal processing steps. Disclosed is a composition of particles containing a shell of inorganic oxides or mixed-metal inorganic oxides and a core material of complex inorganic colored pigment, laser direct structuring additives, laser marking, or other beneficial metal oxides, metal compounds, or mixed-metal oxide materials, wherein the shell material is comprised of any single oxide or combination of oxides is taught. Preferred elements of composition for the shell are oxides and silicates of B, Ni, Zn, Al, Zr, Si, Sn, Bi, W, Mo, Cr, Mg, Mn, Ce, Ti, and Ba (or mixtures thereof). Applications may include, but are not limited to, coatings or plastic articles or materials for molded interconnect devices, durable goods, housings, assemblies, devices, and articles that are to be exposed to additional thermal processing. The resulting core-shell materials function in plastic and coatings formulations by minimizing or eliminating detrimental interactions with the resins and metal containing additives resulting in loss of mechanical properties.