Oxazine Resin with Expandable Microspheres for Composite Curing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current resin systems used in aerospace applications, such as epoxy resins, often increase the polymerization temperature of oxazines and do not provide optimal performance in advanced processes like RTM, VaRTM, and RFI, leading to issues with surface finish and mechanical properties of composite articles.

Innovation Solution

A thermosetting resin composition is used in conjunction with an agent capable of expanding volume, such as expandable microspheres, which generates additional pressure during the curing process, improving surface quality and mechanical properties by maintaining fluid pressure and reducing volatile generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If epoxy resins are used to reduce melt viscosity of oxazines, then processability is improved, but polymerization temperature increases

Engineering Contradiction:

ImproveprocessabilityVSAvoidpolymerization temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters by replacing epoxy resins with oxazine-based resins that have inherent low melt viscosity, eliminating the need for epoxy additives that raise polymerization temperature. This parameter change maintains processability while resolving the temperature contradiction.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes epoxy resin from the composition, using only oxazine-based resins instead. This extraction eliminates the harmful effect of elevated polymerization temperature while preserving the beneficial low viscosity property through the use of pure oxazine systems.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of manufacture

If conventional resin systems are used in RTM processes, then manufacturing is simplified, but surface finish and fiber consolidation are insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidsurface finish

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the resin composition parameters to oxazine-based systems with specific molecular weights and crosslinking characteristics. These parameter changes enable superior fiber consolidation and surface finish while maintaining the simplicity of RTM manufacturing through automated injection and curing processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite resin formulations combining oxazine-based resins with specific crosslinking agents and process additives. These composite materials provide enhanced fiber wetting and consolidation capabilities while maintaining manufacturing simplicity through standardized processing procedures.

Inventive Principle:

Principle #40Composite materials

3Reliability

If resin is injected at low viscosity, then complete wetting is achieved, but voids and shrinkage occur during curing

Engineering Contradiction:

Improvefiber wettingVSAvoidvoid content

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent utilizes the phase transition characteristics of oxazine-based resins, which maintain low viscosity during injection for complete fiber wetting, then undergo controlled crosslinking and volume expansion during curing. This phase transition control prevents void formation while ensuring complete wetting.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent applies local quality control by using expandable microspheres distributed throughout the resin composition. These microspheres provide localized volume expansion during curing, compensating for shrinkage and preventing voids in specific regions while maintaining overall fiber wetting quality.

Inventive Principle:

Principle #3Local quality

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 use of expandable agents in the resin composition enhances the surface finish and mechanical performance of composite articles by maintaining fluid pressure and reducing voids and shrinkage issues during the curing process, resulting in improved fiber consolidation and resin-fiber wetting.

Implementation Method 1

an agent capable of expanding volume, such as expandable microspheres, which generates additional pressure during the curing process

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

curing the thermosetting resin composition-impregnated preform within the mold at a second elevated temperature

Methodology Applied

Scientific EffectCuring polymerization: Photopolymerisation

Data Source

PatentUS9168703B2Curable compositions, processes for using such compositions to prepare composites and processes for preparing composites having superior surface finish and high fiber consolidation

Publication Date: 2015.10.27 HENKEL IP & HOLDING GMBH

AI summary

Curable compositions, such as oxazine-based ones, are useful in applications within the aerospace industry, such as for example as a thermosetting resin composition for use as a matrix resin in processes, such as resin transfer molding, vacuum assisted transfer molding, resin film infusion, prepregging and towpregging, where the composites or laminates so prepared have superior surface finish and high fiber consolidation.