(Meth)Acrylic Impregnation Syrup for Low-Exotherm Composite Curing
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Solution Overview
Problem
The existing (meth)acrylic syrups used for impregnating fibrous substrates face issues with excessive exothermic peaks during polymerization, residual monomer levels, and shrinkage phenomena, leading to defects and reduced mechanical properties in the final composite materials, while also being challenging to formulate with optimal viscosity for complete impregnation.
Innovation Solution
A (meth)acrylic syrup composition characterized by a dynamic viscosity between 10 mPa*s and 10,000 mPa*s, incorporating (meth)acrylic polymer, monomer, and specific fillers such as crosslinked PMMA beads or hollow glass beads, which reduces residual monomer levels and exothermic peak temperatures, ensuring complete and homogeneous impregnation of fibrous substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the syrup contains high proportion of (meth)acrylic monomer to achieve complete polymerization, then the polymerization conversion is improved, but the exothermic peak temperature increases and residual monomer levels rise
Solution Approach 1:
The patent changes the chemical composition parameters of the syrup by introducing specific filler particles (silica, glass beads, metal oxides) with controlled size distribution (D10, D50, D90 parameters) and surface properties. These parameter changes modify the polymerization kinetics, allowing high monomer content (70-90%) to be polymerized completely while reducing the exothermic peak temperature through the filler particles' heat capacity and surface area effects.
2Manufacturing precision
If the syrup contains high proportion of (meth)acrylic monomer to achieve complete polymerization, then the polymerization conversion is improved, but the residual monomer level increases causing health and safety issues
Solution Approach 1:
The patent modifies the syrup composition by adding filler particles with specific size distributions (controlled D10, D50, D90 parameters) and surface characteristics. These parameter changes enhance the polymerization efficiency and completeness, enabling near-total conversion of monomer to polymer even at high monomer concentrations (70-90%), thereby minimizing residual monomer to below detectable or harmful levels.
3Temperature
If the syrup viscosity is increased to reduce monomer content and exothermic peak, then the impregnation quality deteriorates due to poor fiber wetting
Solution Approach 1:
The patent introduces filler particles with specifically controlled size parameters (D10, D50, D90) and surface properties into the syrup. These parameter changes allow the formulation to achieve optimal viscosity balance: the fillers increase viscosity to reduce monomer content and exothermic peak while their small size and surface characteristics maintain the syrup's ability to penetrate and wet fibrous substrates effectively, preventing bare zones and bubbles.
4Manufacturing precision
If the syrup viscosity is optimized for complete impregnation, then the impregnation quality is improved, but the syrup becomes too fluid leading to insufficient viscosity control
Solution Approach 1:
The patent adds filler particles with controlled size distributions (D10, D50, D90 parameters) and surface characteristics to the syrup system. These parameter changes provide viscosity stabilization: the fillers increase the overall viscosity to prevent the syrup from being too fluid, while their distributed size and surface properties ensure uniform viscosity throughout the syrup, maintaining stable composition and preventing segregation during storage and processing.
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 achieves almost complete polymerization with minimal residual monomer, reduced exothermic peak temperatures, and imperceptible shrinkage, resulting in composite parts with improved mechanical properties and reduced defects.
Implementation Method 1
particles having a degree of swelling in the (meth)acrylic monomer of less than 200%
Implementation Method 2
the polymerization of the (meth)acrylic syrup impregnating the fibrous substrate
Implementation Method 3
said liquid (meth)acrylic syrup having a dynamic viscosity of between 10 mPa*s and 10,000 mPa*s
Implementation Method 4
the exothermic peak generated by the polymerization of the syrup is significantly lowered
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 further relates to a method for impregnating a fibrous substrate or long fibres with said viscous liquid syrup. The invention also relates to a fibrous substrate pre-impregnated 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 allows significant reduction of the exothermic peak during the polymerisation of the syrup, reduction of the residual monomer content at the end of the polymerisation, and production of parts in a composite material without defects or with few defects.