Copper Foil Surface Nitrogen Control for Low-Temperature Lamination

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Solution Overview

Problem

The challenge of achieving strong adhesion between a polyvinyl acetal resin film and a copper foil under low temperature and low pressure conditions, which is necessary for manufacturing laminates used in defrosters, due to the low reactivity of polyvinyl acetal resin with copper foil.

Innovation Solution

Control the amount of nitrogen on the treated surface of the copper foil to be between 3.0 atomic % and 20.0 atomic % to improve adhesion, using surface treatments such as silane treatment with nitrogen-containing compounds like amino-functional silane coupling agents, and form a laminate with a polyvinyl acetal resin film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polyvinyl acetal resin film is laminated on copper foil under low temperature and pressure conditions, then the resin film maintains its transparency and thermoplastic properties, but the adhesion between the resin film and copper foil becomes insufficient

Engineering Contradiction:
Improvelamination temperatureVSAvoidadhesion strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention changes the chemical composition parameters of the copper foil surface by controlling the nitrogen content (3.0-20.0 atomic %) introduced through surface treatment. This parameter change enables the copper foil surface to form sufficient adhesion with polyvinyl acetal resin film under low temperature (180°C or less) and low pressure (0.6 MPa or less) lamination conditions, resolving the contradiction between maintaining resin properties and achieving adequate adhesion.

Inventive Principle:
Principle #35Parameter changes

2Strength

If surface treatment is applied to copper foil to improve adhesion, then the adhesion between resin film and copper foil improves, but the manufacturing process complexity increases

Engineering Contradiction:
Improveadhesion strengthVSAvoidsurface treatment process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Instead of complex multi-step surface treatments, the invention achieves improved adhesion by controlling a single key parameter - the nitrogen content (3.0-20.0 atomic %) on the copper foil surface. This simplified approach maintains manufacturing efficiency while achieving the required adhesion strength between the resin film and copper foil.

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

Enhances the adhesion between the copper foil and resin film, allowing for effective lamination under low temperature and low pressure conditions, resulting in a laminate with improved properties.

Implementation Method 1

enhancing the infiltration properties of the polyvinyl acetal resin

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS12623447B2Methods for manufacturing laminated plate and heat generator, and defroster
Publication Date: 2026.05.12 MITSUI MINING & SMELTING CO LTD

AI summary

Provided is a method for manufacturing a laminate that is excellent in adhesion between the copper foil and the resin film while using a polyvinyl acetal resin having low reactivity with the copper foil. This method includes the steps of providing a copper foil having on at least one side a treated surface on which an amount of nitrogen is 3.0 atomic % or more and 20.0 atomic % or less, and attaching or forming a polyvinyl acetal resin film on the treated surface of the copper foil to form a laminate. The amount of nitrogen is a proportion of N in a total amount of N, O, Si, P, S, Cl, Cr, Ni, Cu, Zn, Mo, Co, W, and Fe when the treated surface is subjected to elemental analysis by X-ray photoelectron spectroscopy (XPS).