Polyurethane Adhesive Composition for Moisture-Resistant Aluminum Bonding

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Solution Overview

Problem

Existing polyurethane adhesives face challenges in effectively bonding aluminum alloys due to high surface energy and moisture sensitivity, leading to reduced NCO content, skin formation, and bubble formation in the adhesive, which results in product defects and production breaks.

Innovation Solution

A polyurethane adhesive composition comprising a phosphate modified polyol and a vegetable oil modified polyol, combined with an NCO-terminated polyurethane prepolymer derived from a polyester polyol based on dimeric acid and aromatic dicarboxylic acid, providing improved moisture resistance and adhesion strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polyurethane adhesive is used for bonding aluminum alloys, then adhesion strength is improved, but moisture resistance deteriorates due to high surface energy and absence of organic chemical groups on Al alloy surfaces

Engineering Contradiction:

Improveadhesion strengthVSAvoidmoisture resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent modifies the chemical parameters of the polyol component by incorporating phosphate modified polyol and vegetable oil modified polyol, which changes the surface energy characteristics and chemical group composition to improve both adhesion to aluminum alloys and moisture resistance simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adhesive composition uses a composite polyol system combining phosphate modified polyol and vegetable oil modified polyol with specific polyester polyols, creating a multi-component system that provides both adhesion promotion and moisture resistance properties

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If isocyanate component absorbs moisture, then NCO content is reduced leading to incorrect feed ratios, but skin formation blocks storage tanks and dispensing tunnels

Engineering Contradiction:

ImproveNCO contentVSAvoidskin formation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of moisture absorption by using moisture-scavenging agents and hydrophobic modifications in the polyester polyol structure, transforming the moisture sensitivity issue into an opportunity to create a more stable, less reactive system that maintains consistent NCO content

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces moisture-scavenging agents and hydrophobic modifiers as intermediary substances that mediate between the isocyanate component and environmental moisture, preventing direct harmful reactions while maintaining the desired NCO content

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If polyol component absorbs moisture, then bubbles are formed in cured adhesives, but production breaks occur due to product defects

Engineering Contradiction:

Improveadhesive composition stabilityVSAvoidproduction efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent applies preliminary moisture-scavenging treatment and hydrophobic modification to the polyol component before mixing with isocyanate, preventing moisture-related bubble formation in advance and eliminating the need for production interruptions due to defects

Inventive Principle:

Principle #10Preliminary action

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 composition offers enhanced moisture resistance, adhesion strength, and cost efficiency, preventing skin formation and bubble defects, while maintaining effective bonding of aluminum alloys.

Implementation Method 1

the effective bonding between Al alloys is difficult due to high surface energy and absence of organic chemical groups on the Al alloy surfaces

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

the absorbed moisture leads to reduction of NCO contents and formation of solid skins starting from the top of the components

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

For the polyol part, the absorbed moisture can bring significant bubbles to the cured adhesives after mixing and dispensing the polyol part with isocyanate part

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS20250215290A1Polyurethane adhesive compositions and use of the same

Publication Date: 2025.07.03 DOW GLOBAL TECHNOLOGIES LLC

AI summary

Provided is a polyurethane adhesive composition, comprising, (a) a polyol component, comprising a phosphate modified polyol and a vegetable oil modified polyol, and (b) an isocyanate component, comprising an NCO-terminated polyurethane prepolymer that is the reaction product of (i) a polyester polyol based on a dimeric acid and an aromatic dicarboxylic acid, and (ii) an isocyanate monomer.