Pre-impregnated Fabric Reinforcing Sheets for Rotational Molding
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Solution Overview
Problem
Conventional rotational molding processes struggle to incorporate fiber reinforcement materials due to the rotational motion of the resin, which renders fixation of fibers within the mold difficult, resulting in non-reinforced or unevenly reinforced thermoplastic products.
Innovation Solution
The use of pre-impregnated fabric reinforcing sheets with thermoplastic prepregs, where the fibers are oriented and impregnated with thermoplastic material, allowing for their positioning within the mold during centrifugal casting, enabling the formation of reinforced thermoplastic products with controlled fiber orientation and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional rotational molding is used with loose fiber reinforcement, then the process is simple and easy to manufacture, but the fiber fixation is difficult and reinforcement is uneven
Solution Approach 1:
The patent applies preliminary action by pre-impregnating the fabric reinforcing sheet with thermoplastic resin before placing it in the mold. This pre-coating of resin on the fabric surface allows the fibers to be fixed in their desired orientation before centrifugal casting begins, eliminating the fixation problems that occur with loose fibers during rotational molding.
Solution Approach 2:
The patent uses composite materials by combining fabric reinforcement with thermoplastic resin to create a pre-impregnated reinforcing sheet. This composite structure provides both the mechanical strength of the fabric and the binding properties of the resin, enabling uniform reinforcement while maintaining ease of manufacture through integrated material design.
2Manufacturing precision
If pre-impregnated fabric reinforcing sheets are used, then fiber orientation and distribution are controlled, but the process complexity increases
Solution Approach 1:
The pre-impregnated fabric reinforcing sheet has fibers pre-oriented and pre-coated with resin before molding, which controls fiber orientation and distribution during centrifugal casting without requiring complex in-process control mechanisms.
3Reliability
If loose fibers are used in rotational molding, then material cost is lower, but the reinforcement effectiveness is poor
Solution Approach 1:
The patent creates a composite material system where fabric reinforcement is integrated with thermoplastic resin in a pre-impregnated sheet. This composite structure ensures that the reinforcement materials work together effectively, improving reinforcement effectiveness while reducing waste of both fiber and resin materials through optimized material distribution.
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 method ensures uniform fiber reinforcement and improved mechanical properties by maintaining fiber orientation and distribution, enhancing the structural integrity and design freedom of thermoplastic composite parts, particularly in applications requiring longitudinal strength.
Implementation Method 1
injecting a reactive thermoplastic resin within the centrifugal casting mold so that the reactive thermoplastic resin is centrifugally forced outward within the mold
Implementation Method 2
The reactive thermoplastic resin comprises monomer or oligomer that may polymerize in-situ to form a thermoplastic polymer
Data Source
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AI summary
A reinforced thermoplastic product (400) may include a main body and a fabric reinforcing sheet (100) that is disposed within a wall of the main body. The wall of the main body may be formed of or from a cast thermoplastic material and the fabric reinforcing sheet may extend circumferentially around the main body in order to reinforce the wall. The fabric reinforcing sheet may include a plurality of fiber bundles and a thermoplastic material that impregnates each fiber bundle.