Tape-shaped prepreg warpage control via cooling mechanism
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Solution Overview
Problem
Tape-shaped prepregs with thermoplastic resin compositions face challenges in maintaining handleability and adhesiveness due to warpage and surface roughness issues during the heating and cooling processes, which affect their productivity and moldability.
Innovation Solution
A tape-shaped prepreg with unidirectionally oriented reinforcing fibers and a thermoplastic resin composition, characterized by an arithmetic average roughness of 0.1 to 10 μm and a warpage rate of 5% or less, produced using a method that involves impregnating continuous reinforcing fibers with a molten thermoplastic resin and controlling the heat absorbing capacity of the cooling mechanism to ensure surface smoothness and dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thermoplastic resin composition is used in tape-shaped prepreg, then handleability during molding is improved, but warpage and surface roughness occur during heating and cooling processes
Solution Approach 1:
The patent applies parameter changes by controlling the cooling rate and temperature distribution during the cooling process. Specifically, the cooling rate is adjusted to be within a certain range to prevent excessive warpage and surface roughness while maintaining the handleability benefits of thermoplastic resin. The temperature parameters during heating and cooling are optimized to balance material flow and dimensional stability.
Solution Approach 2:
The patent employs periodic action through controlled heating and cooling cycles. The heating phase melts the thermoplastic resin for impregnation and handling, while the cooling phase solidifies it to reduce warpage. This periodic thermal treatment allows the material to exhibit desirable properties at different stages of the process.
2Manufacturing precision
If cooling rate is increased to reduce warpage, then surface smoothness is improved, but productivity decreases due to longer cycle times
Solution Approach 1:
The patent applies local quality by implementing differential cooling rates in different regions of the tape-shaped prepreg. The cooling mechanism is designed to provide localized cooling zones with different temperatures and cooling rates, allowing critical areas to cool slower for surface quality while other areas cool faster to reduce overall cycle time.
Solution Approach 2:
The patent uses partial action by applying cooling only to specific zones where warpage and surface roughness are most problematic, rather than uniformly cooling the entire prepreg. This selective cooling approach reduces the total cooling time required while maintaining surface quality in critical areas.
3Strength
If thermoplastic resin is heated for impregnation, then adhesiveness is improved, but warpage occurs due to thermal expansion and shrinkage
Solution Approach 1:
The patent applies the counterweight principle by using a support structure or backing material that compensates for the warpage tendency of the thermoplastic resin during heating. The support provides opposing forces to counterbalance the thermal expansion and shrinkage stresses, maintaining dimensional stability while allowing the resin to achieve proper adhesiveness.
Solution Approach 2:
The patent employs composite materials by combining thermoplastic resin with reinforcing fibers in a controlled manner. The fiber-reinforced composite structure provides dimensional stability during heating, counteracting the warpage-prone nature of the thermoplastic matrix while maintaining the adhesiveness benefits of the melted resin.
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 solution provides a prepreg with enhanced handleability and adhesiveness, ensuring high productivity and surface smoothness, allowing for reliable shaping and strong adhesion with other members.
Implementation Method 1
pass through a cooling mechanism to produce a tape-shaped prepreg
Implementation Method 2
shrinkage of the thermoplastic resin composition occurs due to the cooling
Implementation Method 3
impregnating continuous reinforcing fibers with a molten thermoplastic resin
Data Source
AI summary
The invention aims to provide a tape-shaped prepreg including unidirectionally oriented reinforcing fibers and a thermoplastic resin composition and being high in handleability during molding and high in adhesiveness to other members. The tape-shaped prepreg includes unidirectionally oriented reinforcing fibers and a thermoplastic resin composition and has an arithmetic average roughness (Ra) of 0.1 to 10 μm in a direction perpendicular to the orientation direction of the reinforcing fibers, as measured according to JIS B 0601: 2013, and a warpage rate of 5% or less as determined by the procedure specified in (i) to (iii) below: (i) place a test piece of the above tape-shaped prepreg having a length of 100 mm in the fiber orientation direction on a plane in such manner that the end portions curl upward, (ii) measure the vertical distance from the highest position at the right end of the curled tape to the plane, which is denoted by a, and the vertical distance from the highest position at the left end to the plane, which is denoted by b, and calculate the arithmetic average of a and b, which is defined as the warpage distance, and (iii) calculate the warpage rate by the following equation: warpage rate (%)=warpage distance (mm)/100 (mm)×100.