Slit Tape Prepreg Resin Build-up Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current automated lay-up methods for carbon fiber reinforced composite materials face challenges with high tackiness leading to excessive build-up on guide rolls, limiting drapability and laminating performance over a wide temperature range, especially in the AFP method.
Innovation Solution
A prepreg structure with a first layer of carbon fibers impregnated in a first epoxy resin composition and a second layer with a specific thermoplastic resin and epoxy resin composition, characterized by a weight-average molecular weight of 2,000 to 30,000 g/mol and a storage elastic modulus of 8.0×105 to 6.0×106 Pa, reducing build-up on guide rolls and enhancing adhesiveness across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the storage elastic modulus G' of the epoxy resin composition is increased to prevent build-up on guide rolls, then the processability is improved, but the adhesiveness between slit tape prepregs deteriorates
Solution Approach 1:
The invention changes the physical parameters of the epoxy resin composition by controlling the glass transition temperature to be -10°C or higher and less than 7°C, and controlling the storage elastic modulus G' to be within 8.0×10^5 to 6.0×10^6 Pa. These parameter changes enable the resin to have appropriate stiffness for preventing build-up while maintaining adhesiveness for good bonding between prepreg layers.
2Reliability
If the temperature is lowered to prevent build-up of epoxy resin on guide rolls, then the processability is improved, but the adhesiveness during laying-up deteriorates
Solution Approach 1:
The invention changes the temperature parameter by controlling the glass transition temperature of the epoxy resin composition to be -10°C or higher and less than 7°C. This enables the material to maintain appropriate viscosity and adhesiveness at room temperature (20°C or lower) without requiring additional heating, thus resolving the contradiction between processability and adhesiveness.
3Strength
If heating is applied to improve adhesiveness during laying-up, then the laminating performance is improved, but the build-up on guide rolls increases
Solution Approach 1:
The invention changes the material parameters by controlling the glass transition temperature and storage elastic modulus of the epoxy resin composition. These parameter changes enable the resin to maintain good adhesiveness at room temperature without requiring external heating, thereby preventing the build-up problem that occurs when heating is applied.
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 proposed solution significantly reduces resin build-up on guide rolls and improves laminating performance, ensuring high drapability and productivity of carbon fiber reinforced composite materials in automated lay-up processes.
Implementation Method 1
the epoxy resin composition contained in the slit tape prepregs comes out and adheres to the guide rolls
Implementation Method 2
the slit tape prepregs are often heated by an infrared heater or the like to raise the temperature to improve adhesion
Data Source
AI summary
A prepreg having high processability and laminating performance and a method to produce such a prepreg is described, the prepreg comprising at least the components [A] to [E] shown below, and having a structure incorporating a first layer composed mainly of the component [A] and a first epoxy resin composition that contains the components [B] to [D] but which is substantially free of the component [E], and a second layer composed mainly of a second epoxy resin composition that contains the components [B] to [E],[A] carbon fiber,[B] epoxy resin,[C] curing agent,[D] thermoplastic resin, and[E] particles containing a thermoplastic resin as primary component and having a volume-average particle diameter of 5 to 50 μm.