Polycarbonate Composite Melt Stability and Flame Retardancy

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Polycarbonate-based compositions face challenges in melt stability and fiber-matrix coupling, leading to poor mechanical properties and flame retardancy in fiber composite materials, particularly when processed using methods like pressure-shear-vibration, resulting in increased brittleness and dust formation.

Innovation Solution

A fiber composite material comprising at least one layer of fiber material embedded in a composition with aromatic polycarbonate as the matrix, containing specific weight percentages of quartz, cyclic phosphazenes, and phosphorus compounds, which enhances melt stability and impregnation properties, improving fiber coupling and mechanical properties while meeting UL94-V0 flame retardancy standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polycarbonate compositions are used as matrix material for fiber-reinforced composites, then processing is possible, but melt stability is poor and fiber-matrix coupling is insufficient

Engineering Contradiction:
Improvemelt stabilityVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical composition parameters of the polycarbonate matrix by incorporating specific flame retardant compounds and coupling agents. This changes the molecular structure and interfacial properties, thereby improving both melt stability during processing and fiber-matrix adhesion, resolving the contradiction between reliability and ease of manufacture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite matrix system by combining polycarbonate with flame retardant additives and coupling agents. This multi-component composite approach enhances the base polycarbonate's melt stability and bonding characteristics without sacrificing processability, addressing both the reliability and manufacturing ease requirements

Inventive Principle:
Principle #40Composite materials

2Strength

If standard thermoplastic materials are used for fiber reinforcement, then processing is easier, but strength and stiffness are insufficient to approach metal levels

Engineering Contradiction:
Improvetensile strengthVSAvoidprocessing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent employs a fiber-reinforced composite structure where continuous fibers (glass, carbon, or aramid) are embedded in the modified polycarbonate matrix. This composite architecture delivers metal-level strength and stiffness while maintaining the inherent processing advantages of thermoplastics, resolving the contradiction between mechanical performance and ease of manufacture

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the fiber volume fraction, fiber orientation, and matrix composition parameters to achieve maximum mechanical performance. By carefully controlling these parameters, the composite attains metal-comparable strength while remaining processable using standard thermoplastic forming techniques

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If fiber-reinforced composites are produced with conventional polycarbonate, then weight reduction is achieved, but flame retardancy properties are insufficient

Engineering Contradiction:
Improveflame retardancyVSAvoidcomponent weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent incorporates flame retardant compounds into the polycarbonate matrix, modifying its chemical composition to achieve UL94-V0 flame retardancy classification. This additive approach provides adequate flame protection while maintaining the lightweight characteristic of polymer composites, resolving the contradiction between safety requirements and weight reduction goals

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If poor fiber-matrix coupling is accepted in composite production, then processing is simpler, but mechanical properties and surface quality deteriorate with increased brittleness and dust formation

Engineering Contradiction:
Improvesurface qualityVSAvoidcomposition complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces coupling agents as intermediary substances at the fiber-matrix interface. These agents act as mediators that chemically or physically bond to both the fiber surface and the polycarbonate matrix, creating strong interfacial adhesion. This improves surface quality, reduces brittleness and dust formation, while the added compositional complexity is offset by the significant gains in manufacturing precision and product quality

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3728420B1Laminated sheet containing special polycarbonate compositions as matrix material
Publication Date: 2023.02.22 COVESTRO DEUTSCHLAND AG
  • EP3728420B1 patent drawingFigure 1
  • EP3728420B1 patent drawingFigure 2
  • EP3728420B1 patent drawingFigure 3

AI summary

The present invention relates to a composite material containing one or more fiber layers of a fiber material and a matrix material based on an aromatic polycarbonate. The fiber layer(s) is/are embedded in the matrix material. The present invention further relates to a method for producing these fiber composite materials, to multilayer composite materials comprising a plurality of fiber composite layers, and to the use of the composite materials for the production of building or housing parts or housings and to the components, housing parts or housings per se.