Methacrylic Impregnation Syrup for Void-Free Thermoplastic Composites
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Solution Overview
Problem
Thermoplastic composite materials with thermoplastic matrices, such as PMMA and PS, used in composite manufacturing are fragile and lack sufficient impact strength due to the high viscosity of thermoplastic polymers, which hinders uniform impregnation of fibrous substrates and leads to defects like bubbles and voids, reducing the mechanical performance of the final composite material.
Innovation Solution
A liquid (meth)acrylic syrup with a dynamic viscosity between 10 mPa·s and 10,000 mPa·s, comprising (meth)acrylic polymer, (meth)acrylic monomer, and elastomeric domains of flexible macromolecular blocks with a glass transition temperature below 0°C, is used for impregnating fibrous substrates, allowing for improved mechanical properties and uniform impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thermoplastic polymer syrup is used for impregnating fibrous substrate, then the composite material can be thermoformed and recycled, but the high viscosity of the syrup causes poor impregnation uniformity and creates defects like bubbles and voids
Solution Approach 1:
The patent modifies the syrup's viscosity parameters by incorporating specific low-molecular-weight compounds (polyethylene glycol with Mn 200-2000, polypropylene glycol with Mn 200-2000, or dipropylene glycol) in controlled amounts (0.1-10% by weight). This parameter adjustment enables the syrup to achieve optimal flow characteristics for uniform impregnation while preserving thermoplasticity for thermoforming and recycling
Solution Approach 2:
The patent creates a composite syrup system by combining thermoplastic polymer with low-molecular-weight glycol compounds. This composite formulation synergistically provides both the flow properties needed for complete fiber impregnation and the thermoplastic characteristics required for subsequent forming and recycling operations
2Manufacturing precision
If the syrup viscosity is reduced to improve impregnation uniformity, then better fiber wetting is achieved, but the mechanical strength and structural integrity of the composite material decrease
Solution Approach 1:
The patent carefully controls the viscosity reduction by limiting the low-molecular-weight compound content to 0.1-10% by weight. This parameter optimization ensures sufficient flow for complete impregnation while maintaining adequate viscosity to preserve mechanical strength after polymerization
Solution Approach 2:
The low-molecular-weight glycol compounds act as intermediary substances that temporarily modify the syrup's flow characteristics during impregnation. After the polymerization process, these intermediaries are eliminated or become part of the cured matrix, leaving the full mechanical strength intact
3Strength
If thermosetting polymer matrix is used, then high mechanical strength and rigidity are achieved, but the material cannot be easily thermoformed or recycled due to crosslinking
Solution Approach 1:
The patent inverts the conventional approach by using thermoplastic polymer instead of thermosetting polymer as the matrix material. This inversion sacrifices some crosslinked strength but gains thermoforming capability and recyclability, which are then compensated by optimizing the syrup formulation and impregnation process to achieve sufficient mechanical properties
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 process results in composite parts with enhanced mechanical properties, including rigidity greater than 2 GPa, resilience greater than 50 kJ/m², and crack strength greater than 1.5 MPa·m¹/², with virtually no defects, enabling the production of high-performance composite materials suitable for industrial-scale manufacturing.
Implementation Method 1
elastomeric domains consisting of macromolecular blocks of flexible nature, with a glass transition temperature of less than 0° C.
Implementation Method 2
a (meth)acrylic monomer... after polymerization of the syrup
Data Source
AI summary
The invention relates to a liquid (meth)acrylic syrup for impregnating a fibrous substrate. The invention especially relates to a viscous liquid syrup mainly containing methacrylic or acrylic components. The invention also relates to a method for producing such a syrup. The invention relates further to a process for impregnating a fibrous substrate or long fibers with said viscous liquid syrup. The invention also relates to a fibrous substrate preimpregnated with said syrup, which is useful for the production of mechanical or structured parts or products. The invention also relates to a production method for producing mechanical or structured parts or items and to three-dimensional mechanical or structured parts produced by said method. The invention applies to the production of mechanical parts or structural elements made of impact-resistant thermoplastic composite material.