Flame-Retardant Polycarbonate Composition with Cyclic Phosphazene
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Solution Overview
Problem
Existing flame-retardant polycarbonate compositions face challenges in achieving high hydrolysis stability, chemical resistance, and mechanical properties while maintaining low phosphazene content to reduce production costs and meet stringent flame retardancy requirements, particularly in thin-walled applications.
Innovation Solution
A flame-retardant molding composition comprising 60-95 parts by weight of aromatic polycarbonate or polyester carbonate, 1-15 parts by weight of rubber-modified graft polymer, 1-14.5 parts by weight of cyclic phosphazene with a defined oligomer distribution, and optional additives, excluding inorganic flame retardants and organic phosphorus compounds, to achieve enhanced stability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high phosphazene content is used to achieve good flame retardancy, then flame retardancy is improved, but production cost increases
Solution Approach 1:
The patent changes the chemical structure parameters of the phosphazene flame retardant by introducing fluorinated aromatic groups and optimizing the oligomer distribution (predominantly trimers and tetramers). This structural modification enhances the flame retardant efficiency per unit mass, allowing achievement of UL94 V-0 rating with lower overall phosphazene content (1-14.5 parts by weight), thereby reducing production cost while maintaining flame safety
Solution Approach 2:
The patent creates a composite flame retardant system by combining cyclic phosphazene with specific polycarbonate matrices and rubber-modified graft polymers. This composite approach synergistically enhances flame retardancy and mechanical properties simultaneously, allowing reduced phosphazene dosage while maintaining or improving overall material performance
2Ease of manufacture
If phosphazene content is reduced to lower production cost, then production cost is improved, but flame retardancy deteriorates
Solution Approach 1:
The patent modifies the phosphazene molecular parameters by fluorination and oligomer distribution control to maximize flame retardant efficiency. The fluorinated aromatic groups and optimized trimer/tetramer ratio create a highly effective flame retardant structure that maintains UL94 V-0 classification even at reduced concentrations (1-14.5 parts by weight versus traditional higher loadings)
3Strength
If high mechanical properties and hydrolysis stability are achieved, then material performance is improved, but processing difficulty increases
Solution Approach 1:
The patent formulates a composite system combining polycarbonate, rubber-modified graft polymer, and cyclic phosphazene in specific proportions. The rubber modification provides toughness and impact resistance, while the phosphazene delivers flame retardancy and hydrolysis stability. This composite structure achieves high mechanical properties without significantly compromising processability, as all components are compatible thermoplastics that can be processed using conventional methods
Data Source
AI summary
The invention relates to flame-retardant, impact-modified polycarbonate (PC) compositions and molding materials that have good mechanical properties, good chemical resistance, and high hydrolysis stability, containing: A) 60 - 95 parts by weight of aromatic polycarbonate and/or aromatic polyester carbonate, B) 1.0 - 15.0 parts by weight of rubber-modified graft polymer, C) 1.0 - 14.5 parts by weight of at least one cyclic phosphazene according to formula (X), wherein k stands for 1 or an integer number from 1 to 10, preferably for a number from 1 to 8, especially preferably 1 to 5, wherein the trimer portion (k=1) is 60 to 98 mol % with respect to component C and wherein each R is the same or different and stands for an amine residue, C1 to C8 alkyl, preferably methyl, ethyl, propyl, or butyl, which is optionally halogenated, preferably halogenated with fluorine, C1 to C8 alkoxy, preferably methoxy, ethoxy, propoxy, or butoxy, C5 to C6 cycloalkyl, which is optionally substituted with alkyl, preferably with C1 to C4 alkyl, and/or with halogen, preferably with chlorine and/or bromine, C6 to C20 aryloxy, preferably phenoxy or naphthyloxy, which is optionally substituted with alkyl, preferably with C1 to C4 alkyl, and/or with halogen, preferably with chlorine or bromine, and/or with hydroxy, C7 to C12 aralkyl, which is optionally substituted with alkyl, preferably with C1 to C4 alkyl, and/or with halogen, preferably with chlorine and/or bromine, preferably phenyl C1 to C4 alkyl, or a halogen residue, preferably chlorine, or an OH residue, D) 0 - 15.0 parts by weight of rubber-free vinyl (co)polymer or polyalkylene terephthalate, E) 0 - 15.0 parts by weight of additives, F) 0.05 - 5.00 parts by weight of anti-dripping agent, wherein all specifications of parts by weight preferably are normalized in such a way that the sum of the parts by weight of all components A+B+C+D+E+F in the composition is 100. The invention further relates to the use of the compositions to produce molded bodies and the molded bodies produced from the compositions.