Coating Material Composition with Resin Beads for Pressure Mark Resistance

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Solution Overview

Problem

Precoated steel sheets face issues with pressure mark resistance and uniformity due to the use of low-gloss backcoat coating materials, which suffer from viscosity increases, reduced bendability, and gloss transfer, leading to non-uniform final products.

Innovation Solution

A coating material composition with resin beads that have specific compression strength and recovery properties, combined with a controlled mass content and particle diameter, is used to enhance pressure mark resistance, adhesion, and bendability, comprising a urethane reaction-produced resin beads with difunctional isocyanate and a crosslinking agent, applied in a 2-coat 2-bake system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If inorganic powder such as silica is incorporated to produce low-gloss backcoat coating material, then gloss is reduced, but viscosity rises and coatability lowers

Engineering Contradiction:
ImproveglossVSAvoidcoatability
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent changes the physical-chemical parameters of the coating material by incorporating resin beads with specific compression strength (0.01-10 MPa) and recovery rate (≥80%) instead of inorganic powders. This parameter change allows achieving low-gloss effect without the viscosity increase and coatability problems caused by inorganic powder incorporation.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If inorganic powder such as silica is incorporated to produce low-gloss backcoat coating material, then gloss is reduced, but bendability reduces

Engineering Contradiction:
ImproveglossVSAvoidbendability
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of resin beads (with specific elastic properties: compression strength 0.01-10 MPa and recovery rate ≥80%) combined with coating resins. This composite approach provides both the low-gloss effect and maintains bendability, unlike inorganic powders which compromise flexibility.

Inventive Principle:
Principle #40Composite materials

3Illumination intensity

If low-gloss backcoat coating material is used, then gloss transfer occurs due to poor pressure mark resistance, but uniform appearance is required

Engineering Contradiction:
ImproveglossVSAvoiduniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The resin beads in the coating material serve a dual function: they provide the low-gloss effect and simultaneously act as pressure-resistant elements that prevent gloss transfer. When pressure is applied, the beads deform elastically (recovery rate ≥80%) to absorb the pressure without allowing the coated film to deform and transfer gloss, thus the material serves itself to maintain uniformity.

Inventive Principle:
Principle #25Self-service

4Manufacturing precision

If high-gloss backcoat coating material is applied to match upper side gloss, then appearance consistency is improved, but cost increases due to requiring multiple coating material types

Engineering Contradiction:
Improveappearance consistencyVSAvoidcost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent creates a universal backcoat coating material that can be used in all applications regardless of the upper side gloss level. The resin bead-based low-gloss material serves multiple functions: it provides the base low-gloss effect, prevents gloss transfer through its pressure resistance, and works with both high-gloss and low-gloss topcoat materials. This eliminates the need to maintain separate high-gloss and low-gloss backcoat product lines.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution provides a coated film with improved pressure mark resistance, adhesion, and bendability, ensuring a uniform and stable appearance of precoated steel sheets, even under pressure and bending conditions.

Implementation Method 1

the recovery of the resin beads (C) following the 90% pressurized deformation is at least 80%

Methodology Applied
Scientific EffectElastic recovery: Elastic Recovery

Implementation Method 2

crosslinking agent (B)

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS9738810B2Coating material composition, and coated films obtained by the coating thereof
Publication Date: 2017.08.22 AKZO NOBEL COATINGS INT BV

AI summary

A coating material composition for providing coated films is disclosed. The coating material composition contains coated film forming resin (A), crosslinking agent (B), and resin beads (C), in which compression strength of the resin beads (C) at the time of the 10% pressurized deformation of an individual resin bead by means of a micro-compression tester lies between 0.1 MPa and 20 MPa and a recovery of the resin beads (C) following 90% pressurized deformation of an individual resin bead by means of a micro-compression tester is at least 80%.