Epoxy Resin Flexibility via Acid-Terminated Polyester

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Solution Overview

Problem

Epoxy resins used in various applications lack sufficient flexibility, which is essential for characteristics like sealing performance, construction surface followability, and flex resistance.

Innovation Solution

An epoxy resin is developed by reacting an epoxy compound with an acid-terminated polyester, resulting in a product with improved flexibility, characterized by a specific molecular weight range and distribution, and suitable curing agents to enhance its properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a polyalkylene glycol skeleton is introduced into the epoxy resin, then flexibility is expected to be improved, but the epoxy resin cannot provide sufficient flexibility

Engineering Contradiction:
ImproveflexibilityVSAvoidsufficient flexibility performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the chemical structure parameter by replacing the polyalkylene glycol skeleton with a polyester structure containing specific chemical groups (carboxyl, hydroxyl, or ester groups). This structural parameter change enables the epoxy resin to achieve sufficient flexibility (passing the 180° bend test without cracking) while maintaining other required properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining epoxy compound (A) with acid-terminated polyester (B) having specific molecular weight characteristics (Mw/Mn ratio of 1.1 to 10.0). This composite approach, where the polyester acts as a flexible segment within the epoxy resin molecule, successfully provides the required flexibility that single-component epoxy resins cannot achieve.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the molecular weight and molecular weight distribution are controlled within specific ranges, then flexibility is improved, but the synthesis complexity increases

Engineering Contradiction:
ImproveflexibilityVSAvoidsynthesis process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent specifies precise parameter ranges for the acid-terminated polyester (molecular weight 500-10,000 and Mw/Mn ratio 1.1-10.0) and the final epoxy resin (molecular weight 7,000-300,000 and Mw/Mn ratio 1.1-20.0). By controlling these parameters within defined ranges rather than optimizing individually, the synthesis process becomes more manageable while achieving the desired flexibility.

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 resulting epoxy resin and its composition exhibit excellent flexibility, making them suitable for applications in electric and electronic materials, fiber-reinforced resins, adhesives, and paints.

Implementation Method 1

an epoxy resin, which is a reaction product of an epoxy compound (A) and an acid-terminated polyester (B)

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentUS11787898B2Epoxy resin, epoxy resin-containing composition and cured product thereof
Publication Date: 2023.10.17 MITSUBISHI CHEM CORP

AI summary

An object of the present invention is to provide an epoxy resin, an epoxy resin-containing composition, and a cured product which are excellent in flexibility. The present invention relates to an epoxy resin, which is a reaction product of an epoxy compound (A) and an acid-terminated polyester (B). In addition, the present invention relates to an epoxy resin-containing composition and a cured product obtained by using the epoxy resin.