Halogen-Free Aromatic Diphosphate Flame Retardant Synthesis
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Solution Overview
Problem
Current flame retardants for thermoplastic resins, such as halogen-containing compounds and organophosphorus compounds, face issues like corrosion, toxicity, and reduced durability due to by-products formed during the molding process, and existing halogen-free alternatives have low flame-retardant effectiveness or require high amounts, compromising resin properties.
Innovation Solution
A process for preparing a phosphorus flame-retardant composition using an aromatic diphosphate compound with a phosphorus compound having a hydroxyphenyl group as an impurity, synthesized through specific reaction steps involving aromatic monohydroxy and dihydroxy compounds with phosphorus oxyhalide, minimizing by-product formation and maintaining high purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-containing flame retardants are used, then flame-retardant effect is improved, but corrosion and toxicity occur
Solution Approach 1:
The invention extracts and eliminates the harmful halogen component from the flame retardant system by using halogen-free aromatic diphosphates, thereby maintaining flame-retardant effectiveness while removing corrosion and toxicity issues associated with halogen-containing compounds
Solution Approach 2:
The invention changes the chemical composition parameters by transitioning from halogen-containing organophosphorus compounds to halogen-free aromatic diphosphates, fundamentally altering the chemical properties to eliminate harmful effects while preserving flame-retardant functionality
2Object-affected harmful factors
If inorganic compounds or nitrogen compounds are used as halogen-free flame retardants, then toxicity is reduced, but flame-retardant effect deteriorates
Solution Approach 1:
The invention changes the chemical class from inorganic compounds or simple nitrogen compounds to sophisticated organic aromatic diphosphate structures, achieving superior flame-retardant effectiveness through molecular design while maintaining the halogen-free non-toxic advantage
Solution Approach 2:
The invention employs composite molecular structures in aromatic diphosphates that combine aromatic rings with phosphate groups, creating a hybrid structure that delivers both the safety of halogen-free compounds and the effectiveness previously only achievable with halogenated materials
3Reliability
If triphenyl phosphate is used as organophosphorus flame retardant, then flame-retardant effect is improved, but heat resistance deteriorates
Solution Approach 1:
The invention uses composite aromatic diphosphate structures combining rigid aromatic rings with phosphate groups, creating a molecular architecture that inherently resists thermal degradation at high molding temperatures while maintaining flame-retardant activity
Solution Approach 2:
The invention changes the molecular structure parameters by using diphosphate linkages between aromatic rings instead of single phosphate groups, increasing thermal stability and heat resistance to withstand engineering plastic molding temperatures
4Manufacturing precision
If aromatic diphosphate is purified by recrystallization or crystallization, then purity is improved, but productivity deteriorates
Solution Approach 1:
The invention extracts and removes harmful by-products through a selective reaction process that generates minimal impurities, eliminating the need for time-consuming recrystallization or crystallization steps while maintaining high purity of the aromatic diphosphate product
Solution Approach 2:
The invention skips the traditional lengthy purification steps of recrystallization or crystallization by designing a reaction process that inherently produces minimal by-products, rapidly obtaining high-purity product and significantly improving preparation efficiency
5Ease of manufacture
If aromatic diphosphate with hydroxyphenyl by-product is used, then preparation cost is reduced, but resin durability deteriorates
Solution Approach 1:
The invention changes the by-product composition parameters by optimizing the reaction process to minimize hydroxyphenyl group formation, ensuring that any remaining by-products do not contain reactive hydroxyphenyl groups that would compromise resin durability through transesterification
Solution Approach 2:
The invention converts the potential harm of by-product formation into a benefit by designing a reaction process where by-products are either minimized or converted into non-harmful substances that do not interfere with resin performance or durability
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 provides excellent durability and flame retardancy to thermoplastic resins, resisting temperature, humidity, and ultraviolet exposure while maintaining resin properties, with the phosphorus flame-retardant composition being effective at high molding temperatures without generating toxic gases.
Implementation Method 1
an aromatic monohydroxy compound having a group for giving steric hindrance at the ortho position reacts with a phosphorus oxyhalide in the presence of a Lewis acid catalyst to obtain a diaryl phosphorohalidate
Implementation Method 2
the diaryl phosphorohalidate obtained in Step 1 reacts with an aromatic dihydroxy compound that is stoichiometrically equivalent to an amount of the diaryl phosphorohalidate calculated from an amount of the reaction mixture obtained in Step 1 and from a halogen concentration in the reaction mixture
Data Source
AI summary
A phosphorus flame-retardant composition characterized in that it comprises an aromatic diphosphate compound represented by the general formula (I): wherein R1 and R2 are, the same or different, a lower alkyl group, R3 and R4 are, the same or different, a hydrogen atom or a lower alkyl group, Y is a bonding arm, a -CH2-, -C(CH3)2-, - S-, -S02-, -O-, -CO- or -N=N- group, k is 0 or 1, and m is an integer from 0 to 4, and it contains, as an impurity, a phosphorus compound having a hydroxyphenyl group represented by the general formula (II): wherein R1, R2, R3, R4, Y, k and m are as defined in the general formula (I), the content of the phosphorus compound being 1% by area or less as determined by gel permeation chromatography (GPC).