Phosphorus-Containing Phenolic Curing Agent for Epoxy Resins
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Solution Overview
Problem
Current methods for producing phosphorus-containing phenolic compounds face challenges such as low reactivity between phosphorus-containing compounds and phenolic resins, leading to insufficient heat resistance and fire retardancy in cured products, particularly in printed wiring boards and semiconductor sealing materials, due to limited usable phenols and low cross-linking density.
Innovation Solution
A method involving the reaction of an aromatic aldehyde with an alkoxy group substituent and a phosphorus-containing compound, followed by reaction with a phenol, enhances reactivity and heat resistance, allowing for the production of a novel phosphorus-containing phenolic compound that serves as a curing agent for epoxy resins, resulting in improved fire retardancy and heat resistance in cured products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to produce phosphorus-containing phenolic compounds by reacting HCA with formaldehyde or acetone and then with phenolic resin, then fire retardancy is achieved, but reactivity is low resulting in poor heat resistance and failure to pass thermal delamination tests
Solution Approach 1:
The invention changes the chemical parameters by selecting specific aromatic aldehydes with particular substituents (such as -OH, -OCH3, -OC2H5 groups at specific positions) and controlling the molar ratios of reactants. This optimization of chemical parameters significantly improves the reactivity between the phosphorus-containing compound and phenolic resin, enabling the cured product to achieve both fire retardancy and heat resistance exceeding 350°C, thus passing thermal delamination tests.
2Reliability
If halogen fire retardants and antimony compounds are used to impart fire retardancy to epoxy resin compositions, then fire retardancy is achieved, but environmental safety and reliability at high temperature deteriorate due to dioxin emission and cancer risk
Solution Approach 1:
The invention replaces harmful halogen-based fire retardants with a phosphorus-containing phenolic compound derived from environmentally benign reactants. The phosphorus compound achieves effective fire retardancy through its chemical structure and curing mechanism, eliminating the emission of dioxins and other harmful substances while maintaining or improving fire safety performance.
3Quantity of substance
If HCA is allowed to react with formaldehyde or acetone to provide phosphorus compound with hydroxy group, then phosphorus-containing phenolic resin is obtained, but unreacted components remain due to low reactivity resulting in poor thermal decomposition property
Solution Approach 1:
The invention optimizes reaction parameters by selecting specific aromatic aldehydes with reactive substituents and controlling the molar ratios of HCA to aldehyde and aldehyde to phenolic resin within specific ranges. This ensures high reaction completeness with minimal unreacted components, achieving both adequate phosphorus content for fire retardancy and high reaction efficiency.
4Ease of manufacture
If the type of usable polyfunctional phenols is limited due to low reactivity, then production is simplified, but the range of designing phosphorus-containing phenolic resins is considerably limited
Solution Approach 1:
The invention expands the range of usable phenolic compounds by identifying specific structural requirements (aromatic rings with particular hydroxyl group positions and substituents). This broadens the selection of available phenolic resins while maintaining high reactivity, thus increasing design flexibility without significantly complicating the manufacturing process.
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 method significantly enhances the reactivity and heat resistance of phosphorus-containing phenolic compounds, enabling the production of curable resin compositions with excellent fire retardancy and heat resistance, suitable for advanced printed wiring board materials and semiconductor sealing applications.
Implementation Method 1
allowing an aromatic aldehyde (a1) having an alkoxy group as a substituent on an aromatic nucleus to react with an organic phosphorus compound (a2) intramolecularly having a P-H group or a P-OH group; and subsequently allowing the reaction product to react with a phenol (a3)
Data Source
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Figure 9~13
AI summary
Provided are a method for producing a phosphorus-containing phenolic compound in which reactivity is considerably excellent in the reaction between a phosphorus-containing compound and an aromatic nucleus of a phenol; in the case of using a polyhydric phenol or a phenolic resin as the phenol, a novel phosphorus-containing phenolic compound that serves as a curing agent for an epoxy resin and imparts excellent heat resistance to a cured product; a curable resin composition containing the novel phosphorus-containing phenolic compound; a cured product of the curable resin composition; a printed wiring board; and a semiconductor sealing material. An aromatic aldehyde (a1) having an alkoxy group as a substituent on an aromatic nucleus is allowed to react with an organic phosphorus compound (a2) intramolecularly having a P-H group or a P-OH group. The resultant reaction product is then allowed to react with a phenol (a3).