PPS Powder Coating for Thick Smooth Crack-Resistant Films

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing film forming methods using polyphenylene sulfide powder coating materials struggle to create a smooth, thick film with a thickness of 500 μm or more without cracking, due to heat shrinkage and poor surface roughness, which limits their application in high-heat and chemical-resistant coatings for members like heat exchangers and excavating members.

Innovation Solution

A film forming method using a polyphenylene sulfide resin powder coating material, heated above its melting point within a range of 250 to 400°C, forms a film with a thickness of 500 μm or more and a surface roughness of 0.30 μm or less, utilizing a polyphenylene sulfide resin with an MFR of 10 to 100 g/10 min and an average particle size of 20 to 500 μm, without inorganic fillers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If polyphenylene sulfide powder coating material is heated to form a thick film, then film thickness increases, but surface roughness deteriorates and cracking occurs

Engineering Contradiction:
Improvefilm thicknessVSAvoidsurface roughness
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the heating temperature within the specific range of 250°C to 400°C. This temperature parameter control enables the polyphenylene sulfide resin to melt and form a uniform film without excessive heat shrinkage, thereby achieving both thick film formation (500 μm or more) and smooth surface finish (Ra ≤ 0.30 μm) simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions of the polyphenylene sulfide resin, specifically the melting process occurring at temperatures between 250°C to 400°C. By controlling the resin to undergo phase transition from solid to liquid and then solidify upon cooling, the material forms a uniform, crack-free thick film with smooth surface, transforming the harmful heat shrinkage effect into a beneficial forming mechanism

Inventive Principle:
Principle #36Phase transitions

2Volume of moving object

If polyphenylene sulfide powder coating material is heated to form a thick film, then film thickness increases, but cracking occurs on the coating film

Engineering Contradiction:
Improvefilm thicknessVSAvoidcrack resistance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the heating temperature within the specific range of 250°C to 400°C. This temperature parameter control enables the polyphenylene sulfide resin to melt and form a uniform film without excessive heat shrinkage, thereby achieving both thick film formation (500 μm or more) and smooth surface finish (Ra ≤ 0.30 μm) simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies beforehand cushioning by selecting polyphenylene sulfide resin with specific properties (MFR of 10 to 100 g/10 min) and controlling heating parameters in advance to prevent cracking before it occurs. The resin formulation and heating conditions are designed to accommodate thermal expansion and film formation stresses, preventing crack initiation and propagation during the coating process

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 method achieves a smooth, thick film with high hardness and excellent heat and chemical resistance, preventing cracking and ensuring uniform coating on substrates like metal surfaces.

Implementation Method 1

heating the powder coating material at a temperature equal to or higher than a melting point of the polyphenylene sulfide resin

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

due to heat shrinkage and poor surface roughness

Methodology Applied
Scientific EffectHeat shrinkage: Thermal Contraction

Data Source

PatentUS20250361418A1Film forming method, polyphenylene sulfide powder coating material, coating film, and coated article
Publication Date: 2025.11.27 DAIKIN INDUSTRIES LTD

AI summary

Provided is a film forming method that can form a film having a thickness of 500 μm or more with a single coating of a substrate. The present disclosure is a film forming method using a powder coating material containing a polyphenylene sulfide resin, the method including heating the powder coating material at a temperature equal to or higher than a melting point of the polyphenylene sulfide resin and within a range of 250 to 400° C., in which a single coating of a substrate forms a film having a thickness of 500 um or more; and the obtained film has a surface roughness, Ra, of 0.30 μm or less.