Moisture-Curable Adhesive Composition for Wet Surface Bonding

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Solution Overview

Problem

Conventional adhesive compositions used for wet surfaces, such as concrete or wood, face inefficiencies due to the need for coating and drying operations, and lack investigation into adhesive strength on uneven surfaces, particularly with moisture-curable adhesives.

Innovation Solution

An adhesive composition with a base polymer containing no functional groups reactive with moisture-curable components, maintaining low water content (<0.1% by weight) to prevent premature curing, combined with a moisture-curable component in an unreacted state, which reacts with water to enhance adhesion on wet surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid primer composition is used for waterproofing concrete, then close adhesiveness to wet surface is achieved, but coating operation and subsequent drying are required which reduces operation efficiency

Engineering Contradiction:
Improveadhesiveness to wet surfaceVSAvoidoperation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention utilizes the phase transition from liquid adhesive composition to solid adhesive layer through moisture-curing reaction. The adhesive composition is applied in liquid state for easy coating, then undergoes phase transition to solid state through reaction with moisture in the concrete surface, eliminating the need for separate drying operation and improving operation efficiency while maintaining good adhesiveness to wet surfaces

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The adhesive composition performs self-curing by reacting with moisture naturally present in the concrete surface. The moisture-curable component in the adhesive composition automatically reacts with water from the wet concrete surface to form a cured adhesive layer, eliminating the need for external drying equipment or additional operational steps, thus improving operation efficiency

Inventive Principle:
Principle #25Self-service

2Ease of operation

If conventional adhesive compositions are used, then coating operation is simple, but adhesive strength to uneven surfaces such as concrete or wood is insufficient

Engineering Contradiction:
Improvecoating operation simplicityVSAvoidadhesive strength to uneven surface
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention uses a composite adhesive composition containing both a base polymer and a moisture-curable component. The base polymer provides initial adhesion to uneven surfaces through its viscoelastic properties, while the moisture-curable component reacts with moisture in the substrate to form strong chemical bonds, achieving both ease of operation and high adhesive strength to uneven surfaces like concrete and wood

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical state of the adhesive composition from simple physical adhesion to chemical bonding through moisture-curing reaction. The moisture-curable component undergoes chemical transformation upon contact with moisture in the substrate, changing the bonding mechanism from mechanical interlocking to chemical bonding, thereby significantly improving adhesive strength to uneven surfaces while maintaining operational simplicity

Inventive Principle:
Principle #35Parameter changes

3Strength

If moisture-curable component is used to improve adhesion, then adhesive strength increases, but premature curing occurs during storage which reduces storage stability

Engineering Contradiction:
Improveadhesive strengthVSAvoidstorage stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The invention introduces a base polymer as an intermediary substance that physically separates the moisture-curable component from water during storage. The base polymer forms a matrix that traps the moisture-curable component, preventing direct contact with atmospheric moisture and thus preventing premature curing while maintaining storage stability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The base polymer creates an inert environment within the adhesive composition by providing a hydrophobic matrix that excludes water from the moisture-curable component during storage. This inert environment prevents premature hydrolysis and curing of the moisture-curable component, maintaining both adhesive strength potential and storage stability

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

4Reliability

If base polymer with high moisture permeability is used, then adhesion to substrate is improved, but water content increases causing premature reaction with moisture-curable component

Engineering Contradiction:
Improveadhesion to substrateVSAvoidwater content
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention optimizes the moisture permeability parameter of the base polymer to an appropriate level that allows sufficient adhesion to the substrate while limiting excessive water absorption. By carefully selecting and formulating the base polymer with controlled moisture permeability, the invention achieves the right balance between adhesion performance and prevention of premature curing

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

The adhesive composition achieves high adhesive force on wet surfaces with improved storage stability and adhesion to uneven surfaces, ensuring effective bonding over time.

Implementation Method 1

a moisture-curable component, wherein the base polymer contains a polymer having no functional group which reacts with the moisture-curable component

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS11560499B2Adhesive composition, adhesive layer and adhesive sheet
Publication Date: 2023.01.24 NITTO DENKO CORP

AI summary

The present invention relates to an adhesive composition containing a base polymer and a moisture-curable component, wherein the base polymer contains a polymer having no functional group which reacts with the moisture-curable component, and a water content of the base polymer after storage at 25° C. and 50% RH for 24 hours is 0.1% by weight or less, and wherein the moisture-curable component is contained in an unreacted state, an adhesive layer made from the adhesive composition, and an adhesive sheet including the adhesive layer.