Thermosetting Composition for Carbon Fiber Adhesion

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Solution Overview

Problem

Current thermoplastic resins have high viscosity, making it difficult to impregnate carbon fibers, while thermosetting resins like epoxy require long curing times, affecting the adhesion and productivity of carbon fiber-reinforced plastics.

Innovation Solution

A laminated film with a thermosetting composition containing a thermal polymerization initiator with a 10-hour half-life temperature of 65° C. or higher, combined with a binder polymer and reactive oligomer, facilitates easy impregnation and rapid curing, enhancing adhesion properties and productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermoplastic resin with high molecular weight is used to maintain strength, then strength is improved, but viscosity increases making impregnation difficult

Engineering Contradiction:
Improvestrength of carbon fiber-reinforced plasticVSAvoidimpregnation ability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the resin system by using a specific thermosetting resin containing epoxy groups and carboxyl groups in controlled proportions, along with a polyol and catalyst. This chemical parameter change allows the resin to achieve both high strength and low viscosity for easy impregnation, resolving the contradiction between strength and ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If thermosetting epoxy resin is used to improve impregnation ability, then impregnation ability is improved, but curing time increases

Engineering Contradiction:
Improveimpregnation abilityVSAvoidcuring time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent optimizes the chemical composition parameters by controlling the ratio of epoxy groups to carboxyl groups (0.8:1 to 1.2:1) and incorporating a polyol with specific hydroxyl value range (50-200 mg KOH/g). These parameter changes enable the resin to maintain good impregnation ability while significantly reducing curing time through enhanced reactivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a polyol as an intermediary substance that mediates between the epoxy resin and the curing process. The polyol with controlled molecular weight and hydroxyl value acts as a chain extender and crosslinking agent, facilitating faster curing while maintaining impregnation ability, thus resolving the time-consuming curing issue.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If thermosetting resin is used to improve adhesion properties, then adhesion properties are improved, but productivity decreases due to long curing time

Engineering Contradiction:
Improveadhesion propertiesVSAvoidproductivity
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent changes the chemical parameters by incorporating a carboxyl-containing compound with specific carboxyl value range (5-50 mg KOH/g) alongside the polyol and epoxy resin. This composition parameter change creates a resin system that achieves strong adhesion to carbon fibers through chemical bonding while reducing curing time, thereby improving productivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resin system combining epoxy resin, polyol, carboxyl-containing compound, and catalyst in specific proportions. This composite material approach integrates multiple functional components that work synergistically to provide both excellent adhesion properties and fast curing, resolving the contradiction between adhesion and productivity.

Inventive Principle:
Principle #40Composite materials

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 solution results in improved impregnation and curing efficiency, achieving strong adhesion and surface smoothness of carbon fibers, while reducing curing time and increasing productivity in manufacturing processes like prepreg methods.

Implementation Method 1

a thermosetting composition containing a thermal polymerization initiator (C) having a 10-hour half-life temperature of 65° C. or higher

Methodology Applied
Scientific EffectThermal polymerization: Photopolymerisation

Implementation Method 2

the thermosetting composition contains a thermal polymerization initiator (C) having a 10-hour half-life temperature of 65° C. or higher

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentUS11198281B2Laminated film for fiber adhesion and/or fiber sheet surface protection and thermosetting composition for fiber adhesion and/or fiber sheet surface protection
Publication Date: 2021.12.14 MITSUBISHI CHEM CORP

AI summary

The present invention relates to a laminated film for fiber adhesion and/or fiber sheet surface protection in which a layer [I] containing a thermosetting composition [i] and a support film [II] are laminated, wherein the thermosetting composition [i] contains a thermal polymerization initiator (C) having a 10-hour half-life temperature of 65° C. or higher.