Surface-Treated Metal Sheet for Polyolefin Adhesion

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Solution Overview

Problem

Existing surface-treated metal sheets face challenges in achieving high adhesiveness to polyolefin plastics due to limitations in the thickness and viscosity of resin layers containing acid-modified polyolefin, leading to inadequate adhesive strength and bubble formation during the application process.

Innovation Solution

A surface-treated metal sheet design featuring a first layer with a thickness of 15 to 40 μm containing epoxy resin and blocked isocyanate, sandwiched between the metal sheet and a second layer with a thickness of 4 to 30 μm containing acid-modified polyolefin resin, enhancing adhesiveness without increasing resin layer thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resin layer containing acid-modified polyolefin is applied to impart adhesiveness to polyolefin, then adhesiveness to polyolefin is improved, but the resin layer thickness must be increased to achieve sufficient adhesive strength, which increases the overall thickness and may cause bubble formation

Engineering Contradiction:
Improveadhesive strengthVSAvoidresin layer thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The resin layer is divided into two distinct layers: a first layer containing epoxy resin and blocked isocyanate that provides strong bonding to the metal substrate, and a second layer containing acid-modified polyolefin that provides adhesion to the polyolefin plastic. This segmentation allows each layer to be optimized for its specific function without requiring excessive total thickness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite resin structure combining epoxy resin with blocked isocyanate in the first layer, and acid-modified polyolefin in the second layer. This composite approach leverages the complementary properties of different resin systems to achieve both strong substrate bonding and effective plastic adhesion with reduced overall thickness.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If the resin layer thickness is reduced to minimize bubble formation, then bubble formation is decreased, but adhesive strength becomes insufficient

Engineering Contradiction:
Improvebubble formationVSAvoidadhesive strength
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

By segmenting the resin layer into two specialized layers, the invention achieves sufficient adhesive strength with reduced total thickness, thereby minimizing bubble formation during the molding process while maintaining reliable bonding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the chemical composition parameters of the resin layers, using epoxy resin and blocked isocyanate in the first layer with specific thickness, and acid-modified polyolefin in the second layer, to optimize the balance between adhesive strength and bubble formation prevention.

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

This configuration achieves sufficient adhesive strength to polyolefin plastics while minimizing bubble formation and maintaining productivity, even with reduced resin layer thickness, resulting in a composite member with enhanced bonding properties.

Implementation Method 1

the first layer containing an epoxy resin and a blocked isocyanate

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

the second layer containing an acid-modified polyolefin resin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS12059868B2Surface-treated metal sheet for polyolefin adhesion, and composite member
Publication Date: 2024.08.13 KOBE STEEL LTD

AI summary

A surface-treated metal sheet for polyolefin adhesion is provided with a metal sheet, a first layer provided on at least one surface of the metal sheet, and a second layer provided on the first layer, wherein the first layer containing an epoxy resin and a blocked isocyanate, the second layer containing an acid-modified polyolefin resin, the thickness of the first layer being 15 to 40 μm, and the thickness of the second layer being 4 to 30 μm.