Curable Resin Composition for Structural Adhesion

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Solution Overview

Problem

Conventional epoxy resins used in structural adhesives lack flexibility, leading to a trade-off between adhesive strength and flexibility, which compromises their performance when subjected to various stresses, such as those encountered in vehicle bodies where different materials like metal and plastic are bonded.

Innovation Solution

A curable resin composition comprising a compound with two or more glycidyl groups, a glycidyl group-containing acrylic polymer, a tackifier with a phenol skeleton, an inorganic filler, and a curing agent, specifically including bisphenol type epoxy resins and glycidyl group-containing acrylic polymers, to enhance flexibility while maintaining adhesive strength and toughness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If epoxy resin is used as main raw material to increase adhesive strength, then adhesive strength is improved, but flexibility is deteriorated

Engineering Contradiction:
Improveadhesive strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent uses a composite resin composition combining epoxy resin with polyester resin and rubber particles. This composite structure allows the adhesive to maintain the high bond strength of epoxy while incorporating the flexibility and elasticity of polyester and rubber, resolving the contradiction between strength and flexibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces rubber particles with specific size distribution (D10: 0.03-0.1 mm, D50: 0.06-0.2 mm, D90: 0.15-0.5 mm) to provide localized flexibility and stress absorption capabilities within the adhesive matrix, allowing different regions to perform specialized functions.

Inventive Principle:
Principle #3Local quality

2Strength

If epoxy resin is used to maintain resin strength, then resin strength is improved, but flexibility is deteriorated

Engineering Contradiction:
Improveresin strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent creates a composite system where epoxy resin provides structural strength and rigidity, while polyester resin and rubber particles contribute flexibility and elongation capability. This multi-component approach allows simultaneous achievement of high resin strength and flexibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the weight ratios of different components (epoxy resin: 40-70 parts, polyester resin: 20-50 parts, rubber particles: 10-40 parts) to achieve the desired balance between strength and flexibility, demonstrating parameter optimization to resolve the contradiction.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If adhesive strength is increased to improve bonding performance, then adhesive strength is improved, but flexibility is deteriorated

Engineering Contradiction:
Improveadhesive strengthVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs a composite formulation combining epoxy resin (for bonding strength), polyester resin (for flexibility), and rubber particles (for elasticity and stress absorption). This multi-phase composite structure enables the adhesive to simultaneously achieve high reliability and flexibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent uses a silane coupling agent as an intermediary substance that enhances the interface between the adhesive and substrates, improving bond strength without compromising the flexibility provided by the rubber-polyester-epoxy matrix structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves high elongation percentage and toughness coefficient, ensuring the cured product's resistance to fracture under stress, making it suitable for structural adhesion applications requiring both strength and flexibility.

Implementation Method 1

a curable resin composition containing components (A) to (E) below: (A) a compound having two or more glycidyl groups in one molecule (excluding a component (B)); (B) a glycidyl group-containing acrylic polymer; (E) a curing agent

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

an inorganic filler; wherein the component (D) is one or more selected from the group consisting of wollastonite, silica, and calcium carbonate

Methodology Applied
Scientific EffectComposite Materials: Composite Materials

Implementation Method 3

a tackifier having a phenol skeleton and an OH value of 100 or more

Methodology Applied
Scientific EffectAdhesive: Adhesive

Data Source

PatentUS20240239950A1Curable resin composition
Publication Date: 2024.07.18 THREE BOND CO LTD

AI summary

A curable resin composition containing components (A) to (E) below: (A) a compound having two or more glycidyl groups in one molecule (excluding a component (B)); (B) a glycidyl group-containing acrylic polymer; (C) a tackifier having a phenol skeleton and an OH value of 100 or more; (D) an inorganic filler; and (E) a curing agent. One embodiment of the present invention is an adhesive for structure that has high flexibility and is excellent in resin strength, adhesive strength, and toughness coefficient.