Aromatic Polycarbonate LDS Additive Homogeneous Metalization

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Solution Overview

Problem

Polymer compositions with aromatic polycarbonate and laser direct structuring additives often result in non-uniform metalization during the metallization process, leading to pores and uneven metal thickness in irradiated areas, especially when the maximum metal thickness is less than 5 μm or greater than 5 μm.

Innovation Solution

A polymer composition comprising 76.6-99.49% aromatic polycarbonate, 0.5-20% laser direct structuring additive, 0-2.4% rubber-like polymer, and 0.01-1% acid or acid salt, which enhances the homogeneity and average thickness of metal accumulation in metallized areas by reducing the presence of rubber-like polymer and incorporating an acid or acid salt, particularly phosphorous-containing oxy-acids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If laser direct structuring additive is used in aromatic polycarbonate composition, then conductive tracks can be formed on non-conductive parts, but the metalized areas are not homogeneously metalized with pores and non-uniform thickness

Engineering Contradiction:
ImproveLDS process capabilityVSAvoidMetalization homogeneity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters by introducing specific acids (phosphoric acid, phosphorous acid, hypophosphorous acid) and acid salts at controlled concentrations (0.01-1 mass%). This chemical parameter modification fundamentally alters the surface properties and metalization behavior, transforming the non-homogeneous metal deposition into a homogeneous process while maintaining LDS functionality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The acid and acid salt components act as intermediary substances that mediate between the laser direct structuring additive and the metalizing process. These intermediaries modify the surface chemistry to enable uniform metal nucleation and growth, resolving the contradiction between maintaining LDS capability and achieving homogeneous metalization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If metalizing is performed to achieve maximum thickness less than 5 μm, then thin metal layers are formed, but pores are generated in the metalized areas

Engineering Contradiction:
ImproveMetal layer thicknessVSAvoidMetal layer integrity
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

By modifying the chemical composition with specific acids and acid salts, the patent changes the deposition parameters at the molecular level. This enables thin metal layers (<5 μm) to be formed with continuous, pore-free structure by improving wetting and nucleation characteristics during the metalizing process.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If metalizing is performed to achieve maximum thickness greater than 5 μm, then thicker metal layers are formed, but the thickness is not uniform over the metalized areas

Engineering Contradiction:
ImproveMetal layer thicknessVSAvoidThickness uniformity
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The introduction of acids and acid salts modifies the chemical parameters of the system, creating a more controlled deposition environment that maintains uniform thickness distribution even when building thicker metal layers (>5 μm). This prevents the non-uniform accumulation that normally occurs at higher thicknesses.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If rubber like polymer is added to reduce polycarbonate degradation, then degradation is reduced, but metalization homogeneity deteriorates

Engineering Contradiction:
ImprovePolycarbonate stabilityVSAvoidMetalization homogeneity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The acid and acid salt components serve as intermediary substances that override the negative effect of rubber-like polymer on metalization. These intermediaries modify the surface chemistry in a way that promotes homogeneous metal deposition even in the presence of rubber-like polymer, thus resolving the contradiction between polymer stability and metalization quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By changing the chemical composition parameters with controlled amounts of acid and acid salt, the patent modifies the overall system properties to achieve homogeneous metalization while maintaining the protective role of rubber-like polymer against polycarbonate degradation.

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 composition achieves more homogeneous metal accumulation with increased average thickness, reducing pores and ensuring uniform metalization across irradiated areas, even when the metal thickness exceeds 5 μm, thereby improving the metallization process.

Implementation Method 1

capable of being activated by laser radiation and thereby forming elemental metal nuclei

Methodology Applied
Scientific EffectLaser radiation activation: Laser

Implementation Method 2

irradiating areas of said part with laser radiation to activate the plastic surface at locations where the conductive path is to be situated and break down the laser direct structuring additive(s) and release metal nuclei

Methodology Applied
Scientific EffectPhotodissociation: Photodissociation

Implementation Method 3

subsequently metalizing the irradiated areas to accumulate metal on these areas

Methodology Applied
Scientific EffectMetallization: Electroplating

Data Source

PatentUS9159466B2Aromatic polycarbonate composition
Publication Date: 2015.10.13 MITSUBISHI CHEM EURO

AI summary

The present invention relates to a polymer composition comprising the following components: a) 76.6-99.9 mass % of aromatic polycarbonate, b) 0.5-20 mass % of laser direct structuring additive, c) 0-2.4 mass % of rubber like polymer, and d) 0.01-1 mass % of acid and/or acid salt wherein the mass % is calculated relative to the sum of a), b), c) and d). The invention also relates to a moulded part containing this composition, to a circuit carrier containing such molded part and to a process for producing such circuit carrier.