Sheet Prepreg Production via Fiber Spreading and Layering
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Solution Overview
Problem
Existing methods face challenges in uniformly impregnating molten resin into tape-like reinforcing fiber bundles with high melt viscosity, leading to incomplete resin penetration and reduced productivity in producing high-grade sheet-shaped prepregs.
Innovation Solution
A process involving the multilayer arrangement and thickness reduction of tape-like reinforcing fiber bundles using spreading techniques before and after introduction into a die, followed by lamination and resin impregnation, ensures uniform resin distribution and shortens impregnation time, even with high viscosity thermoplastic resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermoplastic resin with high melt viscosity is used as the matrix resin, then the reinforcing effect and strength are improved, but the resin impregnation ability into the tape-like reinforcing fiber bundle deteriorates
Solution Approach 1:
The tape-like reinforcing fiber bundle is divided into a multilayer structure with multiple thin layers stacked in the thickness direction. This segmentation reduces the impregnation distance for the resin in each layer, enabling satisfactory impregnation even with high-viscosity thermoplastic resins while maintaining the reinforcing benefits of continuous fibers.
Solution Approach 2:
The invention transitions from a single-thick layer structure to a multilayer stacked structure, changing the dimensional arrangement of the fiber bundle. By stacking multiple thin layers, the resin can impregnate each layer more effectively from both upper and lower surfaces, resolving the impregnation difficulty caused by high viscosity.
2Strength
If the thickness of the tape-like reinforcing fiber bundle is increased, then the reinforcing effect is improved, but the resin impregnation completeness deteriorates
Solution Approach 1:
Instead of using a single thick fiber bundle, the invention segments it into multiple thinner layers stacked together. Each layer has reduced thickness that allows complete resin impregnation, while the stacked configuration maintains the overall reinforcing capability through continuous fibers spanning multiple layers.
3Manufacturing precision
If the resin impregnation time is extended to improve impregnation completeness, then the impregnation quality is improved, but the productivity deteriorates
Solution Approach 1:
By dividing the thick fiber bundle into multiple thin layers, the resin impregnation distance is significantly reduced in each layer. This enables complete impregnation to be achieved in shorter time, thereby improving productivity without sacrificing impregnation completeness.
Solution Approach 2:
The fiber bundle is pre-formed into a multilayer structure before resin impregnation, creating a configuration that is optimized for rapid and complete resin penetration. This preliminary structural preparation enables faster impregnation while ensuring completeness.
4Ease of manufacture
If spreading means are used to reduce fiber bundle thickness, then the resin impregnation ability is improved, but the device complexity increases
Solution Approach 1:
The invention achieves thickness reduction by forming a multilayer structure through stacking, which can be accomplished with relatively simple spreading means. The segmentation into layers is achieved through the stacking process itself rather than requiring complex thinning equipment.
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
This approach results in a high-grade sheet-shaped prepreg with uniform resin impregnation and enhanced productivity, as the reduced thickness of fiber bundles facilitates easier resin penetration and efficient lamination within the die.
Implementation Method 1
a resin impregnation step for impregnating the molten thermoplastic resin into each of the tape-like reinforcing fiber bundles
Implementation Method 2
impregnating the molten resin into portions between long fibers
Implementation Method 3
a fiber bundle thickness reduction step for widening each of the tape-like reinforcing fiber bundles arranged in the multilayer form by means of spreading to reduce a thickness
Data Source
Figure 1
Figure 2~3(B)
Figure 4~7
AI summary
Disclosed is a process for producing a sheet-shaped prepreg which comprises: a fiber bundle introduction step in which tape-like reinforcing fiber bundles are disposed in a multilayer arrangement in the thickness direction and introduced into a die to which a molten thermoplastic resin has been supplied; a fiber bundle thickness reduction step in which each of the tape-like reinforcing fiber bundles is widened by means of spreading to reduce the thickness; a resin impregnation step in which the tape-like reinforcing fiber bundles are impregnated with the molten resin in the die; and a lamination step in which the plurality of resin-impregnated tape-like reinforcing fiber bundles are laminated in the die. Also disclosed is an apparatus for producing the sheet-shaped prepreg. It is possible to produce a high-grade sheet-shaped thermoplastic prepreg in which the resin has been uniformly and satisfactorily impregnated throughout and the reinforcing fibers have been uniformly arranged. Furthermore, the time required for resin impregnation can be considerably shortened and the productivity can be remarkably enhanced.