Painted Metal Sheet Coating for Bead Retention and Matte Finish

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Solution Overview

Problem

Existing metal sheets with large-size beads in organic films face issues of bead dropout and deformation during coiling or press-working, leading to degraded design properties and contamination of facilities, which affect productivity.

Innovation Solution

A painted metal sheet design with organic resin particles in the coating layer, where the particles are covered by organic resin, ensuring a specific particle diameter and film thickness ratio, and a controlled surface density, preventing dropout and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If large-size beads are added to the organic film to improve abrasion resistance, then the abrasion resistance is improved, but the beads may drop out during coiling or press-working, degrading design properties and contaminating facilities

Engineering Contradiction:
Improveabrasion resistanceVSAvoidbead retention
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent embeds large-size beads (50-200 μm) within a multi-layer organic coating structure where a primer coat anchors the beads and a topcoat seals them. This nested structure prevents bead dropout during coiling and press-working while maintaining the abrasion resistance benefits of the large beads.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent creates a composite organic coating system combining multiple resin types (polyester, acrylic, vinyl chloride) with large-size beads in specific proportions. This composite structure provides both the mechanical strength from large beads and the adhesion/retention properties from the resin matrix, resolving the contradiction between abrasion resistance and bead retention.

Inventive Principle:
Principle #40Composite materials

2Shape

If large-size beads are used in the organic film to enhance design properties, then the design properties are improved, but the beads may be deformed by coiling tension or press-working pressure, causing gloss changes and pressure marks

Engineering Contradiction:
Improvesurface textureVSAvoidbead shape stability
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The patent applies a primer coat containing dispersants and adhesion promoters before applying the topcoat with large beads. This primer layer acts as a cushioning interface that absorbs and distributes coiling tension and press-working pressure, preventing bead deformation and the resulting gloss changes or pressure marks.

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

Solution Approach 2:

The patent specifies precise parameter ranges including bead size (50-200 μm), bead content (1-16.6 volume%), and film thickness ratios (t/T = 0.05-0.50) to optimize the balance between maintaining surface texture from large beads and resisting their deformation under processing stresses.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the organic film contains large-size beads to improve abrasion resistance, then the abrasion resistance is improved, but sufficient care must be taken during handling, reducing productivity

Engineering Contradiction:
Improveabrasion resistanceVSAvoidhandling efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent incorporates large-size beads during the factory coating process rather than requiring post-production handling. The beads are mixed into the paint formulation and applied uniformly by automated coating equipment, eliminating the need for careful manual handling and significantly improving productivity while maintaining abrasion resistance.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4696502A1Coated metal plate
Publication Date: 2026.02.18 NIPPON STEEL CORPORATION
  • EP4696502A1 patent drawingFigure 1A~1B
  • EP4696502A1 patent drawingFigure 1C~1D
  • EP4696502A1 patent drawingFigure 2

AI summary

[PROBLEM] To further improve design properties and productivity of a painted metal sheet. [SOLUTION] The present invention relates to the painted metal sheet including: a metal sheet; an organic resin coating layer located on a surface of the metal sheet; and organic resin particles dispersed in the organic resin coating layer, wherein a content of the organic resin particles dispersed in the organic resin coating layer is 1.0 to 16.6 volume% per side to a total solid volume of the organic resin coating layer, in a case where the organic resin coating layer is viewed from above in plan view, the organic resin particles are dispersed in the organic resin coating layer at a surface density of 30 to 120 particles/mm2, and relationships expressed in Formulas (1) to (4) are established in a cross-section obtained by cutting the organic resin coating layer at any position in a thickness direction.