Liquid (meth)acrylic syrup for impregnating a fibrous substrate, method for impregnating a fibrous substrate, and composite material produced after polymerisation of said pre-impregnated substrate
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Solution Overview
Problem
The existing (meth)acrylic syrups for impregnating fibrous substrates face issues with excessive exothermic peaks during polymerization, residual monomer content, and shrinkage, leading to defects in the final composite material, while maintaining optimal viscosity for impregnation is challenging due to the high monomer content and density differences.
Innovation Solution
A (meth)acrylic syrup composition with a dynamic viscosity between 10 mPa·s and 10,000 mPa·s, incorporating (meth)acrylic polymer, monomer, and specific fillers like crosslinked PMMA beads or hollow glass beads, which reduce residual monomer content and exothermic peak temperature, ensuring complete and uniform impregnation of fibrous substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high monomer content is used in (meth)acrylic syrup to maintain low viscosity for good impregnation, then impregnation quality is improved, but exothermic peak temperature and residual monomer content increase causing defects
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 (0.1-10 μm) and surface properties. This modifies the syrup's physical parameters including viscosity and thermal conductivity, allowing reduced monomer content (while maintaining impregnation quality) and thus lowering the exothermic peak temperature during polymerization.
Solution Approach 2:
The patent creates a composite syrup system by dispersing inorganic filler particles (silica, glass beads, metal oxides) within the (meth)acrylic monomer-polymer mixture. This composite structure provides both the viscosity control needed for impregnation and the thermal management capability to reduce exothermic peak temperature, while the fillers also act as nucleation sites for polymerization.
2Manufacturing precision
If high monomer content is used in (meth)acrylic syrup to maintain optimal viscosity, then impregnation uniformity is improved, but residual monomer content after polymerization increases
Solution Approach 1:
The patent optimizes the molecular weight and composition of the (meth)acrylic polymer component in the syrup. By selecting polymers with specific molecular weights and incorporating them in controlled amounts, the syrup achieves optimal viscosity for uniform impregnation while the polymer chains act as chain transfer agents during polymerization, limiting the formation of residual monomer and improving conversion efficiency.
Solution Approach 2:
The (meth)acrylic polymer in the syrup acts as an intermediary substance that facilitates uniform monomer distribution and polymerization progression. The polymer chains provide a matrix that ensures uniform impregnation while simultaneously serving as initiation and propagation sites that promote complete polymerization, reducing residual monomer content.
3Productivity
If conventional syrup composition is used to achieve complete polymerization, then polymerization efficiency is improved, but shrinkage increases causing defects in composite parts
Solution Approach 1:
The patent modifies the syrup composition by incorporating filler particles and optimizing the monomer-polymer ratio. These parameter changes reduce the overall monomer concentration and introduce rigid filler particles that maintain structural integrity during polymerization, thereby reducing shrinkage while preserving polymerization efficiency through the fillers' nucleation effect.
Solution Approach 2:
The filler particles (silica, glass beads, metal oxides) incorporated in the syrup act as a cushioning framework before polymerization occurs. These particles maintain the spatial structure and prevent excessive shrinkage during the polymerization process, compensating for the volume reduction that would otherwise occur and preventing defects in the final composite parts.
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 virtually complete polymerization with minimal residual monomer, reduced exothermic peak temperature, and imperceptible shrinkage, resulting in composite parts with good mechanical properties and reduced defects, facilitating large-scale, cost-effective, and reproducible manufacturing.
Implementation Method 1
particles with a degree of swelling in the (meth)acrylic monomer of less than 200%
Implementation Method 2
The crosslinking is obtained by curing reactive groups in a prepolymer. Curing may be obtained, for example, by heating the polymer chains in order to crosslink and harden the material permanently.
Data Source
AI summary
The present invention relates to a liquid (meth)acrylic syrup for impregnating a fibrous substrate; a viscous liquid syrup mainly containing methacrylic or acrylic components, and preferably hollow beads; to a process for manufacturing such a syrup; to a process for impregnating a fibrous substrate or long fibers with said viscous liquid syrup; to a fibrous substrate preimpregnated with said syrup, which is useful for manufacturing mechanical or structured parts or products; to a manufacturing process for manufacturing mechanical or structured parts or articles; and to three-dimensional mechanical or structured parts obtained by this process. The invention makes it possible to significantly reduce the exothermic peak during the polymerization of the syrup, to reduce the residual content of monomer at the end of polymerization, and to obtain parts made of composite material that have few or no defects.