CNT Fluoropolymer Powder Coating for Conductive Smooth Surfaces

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Solution Overview

Problem

Conventional electroconductive powder coating compositions face challenges in simultaneously achieving excellent electroconductivity and surface smoothness due to the ruggedness caused by high amounts of electroconductive fillers.

Innovation Solution

A powder coating material composition comprising a fluorine-containing ethylenic polymer and carbon nanotubes, with the carbon nanotubes present in a proportion of 0.01 to 0.35% by mass, and a specific average particle size, forms a coating film with a surface roughness of 3.0 µm or lower and a volume resistivity of 1 × 10^14 Ω·cm or lower.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high amounts of electroconductive fillers are used to achieve excellent electroconductivity, then electroconductivity is improved, but surface smoothness deteriorates due to ruggedness

Engineering Contradiction:
ImproveelectroconductivityVSAvoidsurface smoothness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the key parameter from filler amount to filler type, using carbon nanotubes with specific aspect ratios and high electrical conductivity. This allows achieving excellent electroconductivity at very low concentrations (0.01-0.35% by mass), thereby avoiding the surface roughness problem caused by high filler loading while maintaining superior electroconductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating material combining fluororesin base material with carbon nanotube fillers. This composite structure leverages the smooth surface properties of fluororesin and the high conductivity of carbon nanotubes, achieving both surface smoothness and excellent electroconductivity simultaneously

Inventive Principle:
Principle #40Composite materials

2Reliability

If carbon nanotubes are used as electroconductive material, then electroconductivity is improved, but surface roughness increases

Engineering Contradiction:
ImproveelectroconductivityVSAvoidsurface roughness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes carbon nanotube parameters including aspect ratio (length/diameter), purity, and dispersion state. By controlling these parameters and using very low concentrations (0.01-0.35% by mass), the patent achieves high electroconductivity while minimizing surface roughness to Ra of 3.0 µm or lower

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent ensures uniform local distribution of carbon nanotubes within the fluororesin matrix through proper dispersion techniques. This localized uniform distribution prevents agglomeration and surface protrusions, maintaining surface smoothness while ensuring consistent electroconductivity throughout the coating

Inventive Principle:
Principle #3Local quality

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 both high electroconductivity and surface smoothness, with the carbon nanotubes providing excellent electroconductive performance in a small amount, enhancing the coating film's properties.

Implementation Method 1

the electroconductive material is at least partially a carbon nanotube... the carbon nanotube is contained in a proportion of 0.01 to 0.35% by mass... a volume resistivity of 1 × 10^14 Ω·cm or lower

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

A coating film of 80 μm in thickness, obtained by electrostatically coating the powder coating material composition on a metal plate

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 3

subsequently forming a film at a temperature higher by 80°C than the melting point of the fluorine-containing ethylenic polymer

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4450569B1Powder coating composition, coating, multilayered coating, and coated article
Publication Date: 2026.02.18 DAIKIN INDUSTRIES LTD

AI summary

Provided is a powder coating material composition which can simultaneously satisfy both of excellent electroconductive performance and surface smoothness. The powder coating material composition contains a fluorine-containing ethylenic polymer and an electroconductive material, wherein the electroconductive material is at least partially a carbon nanotube, and the carbon nanotube is contained in a proportion of 0.01 to 0.35% by mass to the total amount of the fluorine-containing ethylenic polymer and the electroconductive material.