Two-Part Curable Adhesive for Alkali-Detachable Laminates

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Solution Overview

Problem

Conventional packaging materials are not biodegradable and recyclable, leading to environmental degradation, and there is a need for laminating adhesives that provide sufficient performance, biodegradability, and detachability in aqueous alkali solutions.

Innovation Solution

A two-component curable adhesive comprising a polyester polyol compound with a specific molecular weight range and a polyisocyanate compound, both derived from aliphatic alcohols with quaternary carbon atoms and trivalent or more hydroxy groups, forming a laminate with detachable and biodegradable properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional synthetic resin packaging materials are used, then adhesive performance and durability are maintained, but biodegradability and environmental compatibility deteriorate

Engineering Contradiction:

Improveadhesive performanceVSAvoidenvironmental degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive by using polyester polyol with specific molecular weight (500-20,000) and specific structural features (quaternary carbon atom, trivalent or more hydroxy groups) to achieve both adequate adhesive performance and biodegradability, resolving the contradiction between reliability and environmental harm

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive system combining polyester polyol and polyisocyanate compound with specific structural characteristics, forming a cured adhesive that maintains performance while enabling biodegradation and alkali treatment separability, thus addressing both reliability and environmental concerns

Inventive Principle:

Principle #40Composite materials

2Strength

If laminated packaging materials are designed for durability, then adhesive strength is improved, but separability and recyclability deteriorate

Engineering Contradiction:

Improveadhesive strengthVSAvoidseparability for recycling

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent introduces local chemical characteristics into the adhesive structure by incorporating quaternary carbon atoms and specific hydroxy group configurations that create regions susceptible to alkali treatment, allowing the adhesive to exhibit both strong bonding strength and controlled separability under specific recycling conditions

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses aqueous alkali solution as an intermediary substance that can selectively interact with the specific chemical structure of the cured adhesive (containing quaternary carbon atoms and hydroxy groups) to enable separation of laminated materials without compromising the adhesive's original bonding strength

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If biodegradable materials are used in adhesives, then environmental compatibility is improved, but adhesive performance and durability deteriorate

Engineering Contradiction:

ImprovebiodegradabilityVSAvoidadhesive performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent optimizes the molecular weight parameter of polyester polyol (500-20,000) and the structural parameters (quaternary carbon atom, hydroxy group valency) to achieve the right balance between biodegradability and adhesive performance, ensuring the cured adhesive maintains adequate strength while being environmentally compatible

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 enables effective biodegradability and recyclability of laminates through alkali treatment, maintaining adhesive performance and facilitating separation into layers for recycling.

Implementation Method 1

a two-component curable adhesive containing a polyol composition (X) containing a polyester polyol compound (A) and a polyisocyanate composition (Y) containing a polyisocyanate compound (B)

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

detachability when immersed in an aqueous alkali solution and a laminate and a packaging material having biodegradability and recyclable with an alkali treatment liquid

Methodology Applied

Scientific EffectAlkali treatment: Hydrolysis

Implementation Method 3

having excellent biodegradability and detachability when immersed in an aqueous alkali solution

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentEP4640783A1Two-part curable adhesive, multilayer body and package

Publication Date: 2025.10.29 DIC CORP

AI summary

Provided are a two-component curable adhesive containing a polyol composition (X) containing a polyester polyol compound (A) and a polyisocyanate composition (Y) containing a polyisocyanate compound (B), the polyester polyol compound (A) having a number average molecular weight in a range of 500 to 20,000, and either or both of the polyester polyol compound (A) and the polyisocyanate compound (B) being a reaction product of an aliphatic alcohol having a quaternary carbon atom and having trivalent or more hydroxy groups; a laminate; and a packaging material.