Liquid Acrylic Syrup Impregnation for Fire-Resistant Composites
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Solution Overview
Problem
Existing thermoplastic composite materials face challenges in achieving optimal fire resistance and uniform impregnation of fibrous substrates, with current flame-retardant additives often disrupting viscosity and thermoplastic properties, leading to defects and reduced mechanical performance.
Innovation Solution
A liquid (meth)acrylic syrup containing (meth)acrylic polymer, monomer, and phosphorus-based additives or hydrated mineral fillers, with a dynamic viscosity between 10 mPa·s and 10,000 mPa·s, is used for impregnating fibrous substrates, ensuring complete wetting and enhanced fire resistance without halogenated compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If flame-retardant additives are added to thermoplastic polymer syrup to improve fire resistance, then fire resistance is improved, but viscosity is disrupted and thermoplastic properties are impaired
Solution Approach 1:
The patent modifies the chemical composition parameters of the flame-retardant additives, specifically using phosphorus-based compounds (phosphinates, diphosphinates, phosphonates, phosphates) and hydrated mineral fillers with controlled particle sizes and distributions. These parameter changes allow the additives to integrate into the syrup without excessively increasing viscosity, maintaining flow properties necessary for proper fiber impregnation while achieving fire resistance with LOI > 32.
Solution Approach 2:
The patent creates a composite flame-retardant system by combining multiple components: phosphorus-based organic compounds, hydrated mineral fillers (such as aluminum trihydrate), and thermoplastic polymer syrup. This composite approach allows each component to contribute different properties - the phosphorus compounds provide flame inhibition through chemical mechanisms, the mineral fillers provide physical barrier effects and endothermic decomposition, while the polymer syrup maintains the thermoplastic matrix - together achieving fire resistance without compromising viscosity or processing properties.
2Object-affected harmful factors
If flame-retardant additives are added to thermoplastic polymer syrup to improve fire resistance, then fire resistance is improved, but thermoplastic properties are impaired
Solution Approach 1:
The patent carefully controls the concentration parameters of flame-retardant additives, limiting them to less than 50% by weight of the total syrup composition. This parameter control ensures that the thermoplastic polymer matrix remains the dominant phase, maintaining melt flow, reprocessability, and forming characteristics. The syrup retains sufficient thermoplastic properties to be heated, pumped, and molded while incorporating adequate flame-retardant content for fire safety performance.
Solution Approach 2:
The thermoplastic polymer syrup itself acts as an intermediary medium that carries the flame-retardant additives through processing. The syrup's viscosity and flow properties enable uniform distribution of flame-retardant particles throughout the fibrous substrate during impregnation, while the polymer matrix binds the additives in place during molding and curing. This intermediary role allows the system to maintain thermoplastic processability while achieving fire resistance.
3Ease of operation
If the syrup viscosity is too low, then impregnation is easy, but naked zones and bubbles appear causing defects
Solution Approach 1:
The patent optimizes the viscosity parameter of the thermoplastic syrup to a specific range that balances impregnation ease with defect prevention. By controlling syrup temperature, polymer molecular weight, and additive concentration, the viscosity is maintained within optimal limits during impregnation - low enough to flow into and wet the fibrous substrate completely, but high enough to prevent excessive drainage and bubble formation. This parameter optimization ensures uniform impregnation without naked zones or voids.
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 thermoplastic composite materials with improved fire resistance, characterized by high limiting oxygen index, low peak heat release rate, and reduced toxic fume emission, while maintaining thermoplastic properties and minimizing defects.
Implementation Method 1
The liquid (meth)acrylic syrup for impregnating a fibrous substrate, said fibrous substrate consisting of long fibers... ensuring complete wetting
Implementation Method 2
a (meth)acrylic monomer... after polymerization of the syrup
Data Source
AI summary
The present invention relates to a liquid (meth)acrylic syrup for impregnating a fibrous substrate. The present invention relates in particular to a viscous liquid syrup mainly containing methacrylic or acrylic components. The invention also relates to a process for manufacturing such a syrup. The invention also relates 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 manufacturing mechanical or structured parts or products.The present invention also relates 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 applies to the preparation of mechanical parts or structural elements made of fire-resistant thermoplastic composite material.