Phosphorus Oligomer Curing Agent for Epoxy Resin Solubility

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Solution Overview

Problem

Epoxy resin compositions with phosphorus-atom-containing bisphenols exhibit high crystallinity and poor solvent solubility, making them unsuitable for varnish production and lacking sufficient flame retardancy when used as curing agents for epoxy resin, particularly in high-temperature applications like printed circuit boards.

Innovation Solution

A phosphorus-atom-containing oligomer composition with a specific molecular structure, obtained by reacting a phosphorus-atom-containing compound and o-hydroxybenzaldehyde, is used as a curing agent for epoxy resin, enhancing solvent solubility and providing excellent flame retardancy and heat resistance, with a glass transition point suitable for withstanding high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phosphorus-atom-containing bisphenols are used as epoxy resin curing agents, then flame retardancy is improved, but solvent solubility deteriorates and crystallinity increases

Engineering Contradiction:
Improveflame retardancyVSAvoidsolvent solubility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention changes the molecular structure parameters by replacing the bisphenol structure with a phenolic resin structure containing phosphorus atoms. This structural parameter change reduces crystallinity and improves solvent solubility while maintaining flame retardancy through the phosphorus content

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite curing agent that combines phenolic resin with phosphorus-containing compounds. This composite structure integrates the solubility benefits of phenolic resins with the flame retardancy of phosphorus compounds, resolving the contradiction between these two properties

Inventive Principle:
Principle #40Composite materials

2Reliability

If phosphorus-atom-containing bisphenols are used as epoxy resin curing agents, then flame retardancy is improved, but heat resistance deteriorates

Engineering Contradiction:
Improveflame retardancyVSAvoidheat resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention combines phenolic resin with phosphorus-containing compounds to create a composite curing agent. The phenolic resin provides the heat resistance necessary for high-temperature applications, while the phosphorus compounds contribute flame retardancy, thus resolving the contradiction between these two thermal properties

Inventive Principle:
Principle #40Composite materials

3Reliability

If phosphorus-atom-containing bisphenols are used as epoxy resin curing agents, then flame retardancy is improved, but manufacturing difficulty increases due to high melting point

Engineering Contradiction:
Improveflame retardancyVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the melting point parameter by replacing the bisphenol structure with a phenolic resin structure. Phenolic resins typically have lower melting points and better processability, making the curing agent easier to manufacture and handle while maintaining the flame retardancy provided by the phosphorus atoms

Inventive Principle:
Principle #35Parameter changes

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 phosphorus-atom-containing oligomer composition significantly improves solvent solubility and flame retardancy of the cured product, enabling its use in varnishes for printed circuit boards and ensuring high heat resistance and performance in T288 tests.

Implementation Method 1

a phosphorus-atom-containing oligomer composition including a mixture of a phosphorus-atom-containing compound represented by structural formula (1) below with n representing 0 and a phosphorus-atom-containing oligomer represented by structural formula (1) below with n representing 1 or more

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP2682398B1Phosphorus-atom-containing oligomer composition, curable resin composition, substance resulting from curing same, and printed circuit board
Publication Date: 2016.05.11 DIC CORP
  • EP2682398B1 patent drawingFigure 1~3
  • EP2682398B1 patent drawingFigure 4~8
  • EP2682398B1 patent drawing

AI summary

Solubility in organic solvents is dramatically improved while achieving excellent flame retardancy and heat resistance as a cured product. A phosphorus-atom-containing oligomer is used as a curing agent for epoxy resin, the phosphorus-atom-containing oligomer being a mixture of a phosphorus-atom-containing compound represented by structural formula (1) below with n representing 0 and a phosphorus-atom-containing oligomer represented by structural formula (1) below with n representing 1 or more: (where R1 to R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or the like; X represents a hydrogen atom or a structural unit represented by structural formula (x1) below: where, in structural formula (x1) , R2 to R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or the like), wherein a content of the phosphorus-atom-containing oligomer represented by general structural formula (1) with n representing 1 or more is in the range of 5 to 90% on a peak area basis in GPC measurement.