Epoxy Resin Curing Agent Blend for FRP Filtration Control
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Solution Overview
Problem
The use of diaminodiphenyl sulfone as a curing agent in fiber-reinforced polymer (FRP) production leads to filtration issues at temperatures below 120°C, resulting in reduced physical properties and curing failures, making it difficult to control the production process and achieve stable physical properties in FRP products.
Innovation Solution
A production method using a blend of 3,3'-diaminodiphenyl sulfone and 4,4'-diaminodiphenyl sulfone with specific particle size and blending ratios, allowing the curing agents to dissolve in the epoxy resin at lower temperatures, reducing filtration and improving the stability of the curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If diaminodiphenyl sulfone is used as a curing agent at temperatures below 120°C, then the production process can be operated at milder temperatures, but the curing agent is filtered by the reinforcing fiber surface leading to curing failure and deteriorated physical properties
Solution Approach 1:
The invention divides the single curing agent (diaminodiphenyl sulfone) into two isomeric components (3,3'-diaminodiphenyl sulfone and 4,4'-diaminodiphenyl sulfone) with different particle sizes. The 3,3'-isomer with smaller particle size (D90: 5-20 μm) can dissolve at lower temperatures without filtration, while the 4,4'-isomer with larger particle size (D90: 20-40 μm) provides structural support. This segmentation allows the curing process to proceed at milder temperatures below 120°C while preventing filtration and ensuring complete curing.
Solution Approach 2:
The invention assigns different functional properties to different isomeric components of the curing agent. The 3,3'-diaminodiphenyl sulfone component is optimized for dissolution and reactivity at lower temperatures, while the 4,4'-diaminodiphenyl sulfone component provides structural stability and prevents filtration. This local quality differentiation enables the system to achieve both mild processing conditions and reliable curing performance.
2Strength
If diaminodiphenyl sulfone is used as a curing agent, then heat resistance property is improved, but filtration occurs at temperatures below 120°C causing curing failure
Solution Approach 1:
The curing agent is segmented into two isomeric forms with distinct particle size distributions. The 3,3'-isomer (smaller particles, D90: 5-20 μm) ensures complete dissolution and uniform curing at lower temperatures, while the 4,4'-isomer (larger particles, D90: 20-40 μm) maintains heat resistance properties. This segmentation prevents filtration while ensuring curing uniformity and maintaining the desired heat resistance of the final composite material.
Solution Approach 2:
The invention creates a composite curing agent system by combining two isomeric forms of diaminodiphenyl sulfone in specific proportions (3,3'-isomer: 40-80 wt%, 4,4'-isomer: 20-60 wt%). This composite approach allows the system to simultaneously achieve uniform dissolution, prevent filtration, ensure complete curing, and maintain heat resistance properties that would not be possible with a single isomeric component.
3Stability of the object's composition
If the epoxy resin composition is heated to dissolve the curing agent, then the curing agent dissolves completely, but the curing reaction proceeds making process control difficult
Solution Approach 1:
The curing agent is divided into two isomeric components with different dissolution characteristics. The 3,3'-diaminodiphenyl sulfone component dissolves completely at lower temperatures (below 120°C) due to its smaller particle size, while the 4,4'-diaminodiphenyl sulfone component provides structural stability. This segmentation allows complete dissolution to be achieved at milder temperatures where the curing reaction proceeds more slowly, thereby improving process control.
Solution Approach 2:
The invention changes the physical parameters of the curing agent by using isomeric forms with different particle size distributions. The 3,3'-isomer with smaller particle size (D90: 5-20 μm) dissolves more readily at lower temperatures, enabling complete dissolution without requiring high temperature heating that would accelerate the curing reaction. This parameter change allows dissolution completeness to be achieved while maintaining ease of process control.
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 method enables the curing agent to dissolve at milder temperatures, reducing filtration and improving the physical properties of FRP, enhancing the production process control and stability of the final product.
Implementation Method 1
a first curing agent, 3,3'-diaminodiphenyl sulfone, and a second curing agent, 4,4'-diaminodiphenyl sulfone, as long as a blending ratio of the first curing agent to the second curing agent is 3/7 to 7/3 by weight
Implementation Method 2
impregnating a fiber assembly with the epoxy resin composition, and curing the impregnated fiber assembly
Data Source
Figure 1~2
AI summary
Provided is a method for producing a good epoxy resin composition for obtaining fiber-reinforced plastics. A production method for obtaining a fiber-reinforced composite material by impregnating a fiber assembly with an epoxy resin composition and then curing the epoxy resin composition, wherein the epoxy resin composition contains a component [A], a component [B] and a component [C] respectively satisfying the conditions described below. When the blending amount of the component [B] is set to b parts by mass and the blending amount of the component [C] is set to c parts by mass relative to 100 parts by mass of the component [A] contained in the epoxy resin composition, formula (2) is satisfied within the range of formula (1), formula (4) is satisfied within the range of formula (3), and formula (6) is satisfied within the range of formula (5). The epoxy resin composition is blended at a temperature of 60-80°C (inclusive).