Impregnation process for a fibrous substrate, a liquid (meth) acrylic syrup for the impregnation process, its method of polymerization and structured article obtained thereof
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Solution Overview
Problem
Current impregnation processes for fibrous substrates with thermoplastic polymers face challenges such as high viscosity issues, thermoinduced degradation, and environmental concerns due to solvent use, limiting the production of composite materials with desired mechanical properties and recyclability.
Innovation Solution
An impregnation process using a liquid (meth)acrylic syrup with a dynamic viscosity of 10 mPa*s to 10000 mPa*s, comprising (meth)acrylic polymer, monomer, and an initiator, applied in a closed mold, ensuring complete and homogeneous wetting of the fibrous substrate, and subsequent polymerization to produce composite materials with high stiffness and UV resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thermoplastic polymer is used to impregnate fibrous substrate, then the composite material can be recycled and reshaped, but the high viscosity of molten polymer prevents homogeneous impregnation of fibers
Solution Approach 1:
The patent changes the chemical composition parameters of the impregnating liquid by using a syrup containing both monomer and oligomer/polymer in specific ratios (20-80 wt% monomer, 20-80 wt% oligomer/polymer). This parameter optimization allows the liquid to have appropriate viscosity for fiber impregnation while maintaining the ability to form a thermoplastic matrix upon curing, thus achieving both homogeneous impregnation and recyclability.
Solution Approach 2:
The patent creates a composite impregnating liquid system combining monomer and oligomer/polymer components. This composite approach allows the liquid phase to penetrate fibers effectively while the polymerization process creates the thermoplastic matrix structure, resolving the contradiction between liquid flowability and final matrix performance.
2Ease of operation
If the chain length or molecular mass of thermoplastic polymer is reduced to decrease viscosity, then fluidity improves for impregnation, but the mechanical properties of the composite material deteriorate
Solution Approach 1:
The patent optimizes the molecular weight distribution by using oligomers with specific weight average molecular weights (10,000-1,000,000 g/mol) combined with monomers. This parameter control ensures the liquid has sufficient fluidity for impregnation while the oligomer chains provide adequate mechanical strength in the final composite material.
Solution Approach 2:
The patent performs preliminary action by pre-forming the syrup with optimized monomer-oligomer ratios before impregnation. This preliminary preparation ensures that when polymerization occurs, the network structure develops with appropriate crosslinking density to achieve both processability and mechanical performance.
3Ease of operation
If temperature is increased to reduce viscosity of thermoplastic polymer, then fluidity improves for impregnation, but thermoinduced degradation occurs reducing molecular weight and mechanical properties
Solution Approach 1:
The patent changes the compositional parameters of the syrup to include 20-80 wt% monomer and 20-80 wt% oligomer/polymer, which fundamentally alters the viscosity-temperature relationship. This composition allows impregnation at lower temperatures (20-100°C) avoiding thermal degradation, while still achieving adequate fluidity for fiber wetting.
Solution Approach 2:
The oligomer/polymer component acts as an intermediary that reduces the viscosity of the impregnating liquid without requiring high temperatures. The monomer-oligomer mixture provides the necessary fluidity at low temperatures, preventing thermoinduced degradation while enabling complete fiber impregnation.
4Strength
If thermosetting polymer is used for matrix material, then mechanical performance is improved, but the composite material cannot be easily shaped or recycled
Solution Approach 1:
The patent changes the fundamental chemical parameter of the matrix material from thermosetting to thermoplastic by using polymerizable monomers and oligomers that form thermoplastic networks upon curing. This parameter change enables both high mechanical performance through network formation and recyclability through melting and reshaping capabilities.
Solution Approach 2:
The patent inverts the conventional approach by using a thermoplastic matrix instead of thermosetting. This inversion allows the composite to be recyclable and reshapeable while maintaining mechanical performance through optimized thermoplastic polymer network formation from the monomer-oligomer syrup.
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 achieves composite materials with high stiffness (young modulus of at least 15 GPa), minimal defects, and the ability to be recycled, while being cost-effective and environmentally friendly.
Implementation Method 1
The liquid (meth) acrylic syrup has a dynamic viscosity of a value in the range from 10 mPa*s to 10000 mPa*s, preferably from 50 mPa*s to 5000 mPa*s and advantageously from 100 mPa*s to 1000 mPa*s
Implementation Method 2
c) at least one initiator or initiating system for starting the polymerization of the (meth) acrylic monomer
Data Source
AI summary
The present invention relates to an impregnation process for a fibrous substrate, a liquid composition for implementing this process and the obtained impregnated fibrous substrate. The impregnated fibrous substrate is suitable for manufacturing mechanical or structured parts or articles. In particular the present invention deals with an industrial process for impregnating a fibrous substrate or long fibers with a viscous liquid composition containing mainly methacrylic or acrylic components. This viscous composition is called hereafter liquid (meth) acrylic syrup. The invention concerns also a fibrous substrate pre-impregnated with said syrup which is useful for manufacturing mechanical or structured parts or articles. More particular the impregnation of fibrous substrate with the (meth) acrylic syrup is achieved in a closed mold. The present invention concerns also manufacturing process for manufacturing mechanical or structured parts or articles and three-dimensional mechanical or structured parts obtained by this process.