Phosphate-Modified Pressure-Sensitive Adhesive for Flame Retardancy

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Solution Overview

Problem

Existing polymeric materials used in applications with fire risk face challenges with halogenated flame retardants being hazardous and non-halogenated alternatives like ammonium polyphosphates, metal hydroxides, and zinc borates requiring high loading levels, leading to poor adhesion and mechanical properties.

Innovation Solution

A (meth)acrylate copolymer with pendent phosphate-containing groups is formed by reacting a precursor (meth)acrylate copolymer with an epoxy-functionalized phosphate compound, covalently attaching phosphate groups to enhance flame retardancy without compromising adhesion and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogenated flame retardants are used, then fire retardation efficiency is improved, but hazardous substance levels increase

Engineering Contradiction:

Improvefire retardation efficiencyVSAvoidhazardous substance levels

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful halogenated flame retardants into beneficial non-halogenated alternatives by incorporating phosphate-containing groups directly into the polymer structure. The phosphate groups provide flame retardation through endothermic decomposition and radical scavenging mechanisms, eliminating hazardous halogenated substances while maintaining fire safety performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical composition parameters by replacing halogenated compounds with phosphate-containing groups in the polymer structure. This parameter change maintains flame retardation efficiency while eliminating hazardous substances, achieving both fire safety and environmental compliance.

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If non-halogenated flame retardants like ammonium polyphosphates are added, then hazardous substance levels are reduced, but adhesion and mechanical properties deteriorate

Engineering Contradiction:

Improvehazardous substance levelsVSAvoidadhesion and mechanical properties

Core Design Contradiction:

Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent merges the flame retardant function with the polymer structure by incorporating phosphate-containing groups directly into the polymeric material. This integration ensures that the flame retardant is not just added as a separate component but is fundamentally part of the polymer chain, maintaining structural integrity and adhesion while providing fire protection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite material where phosphate-containing groups are integrated within the polymer matrix. This composite structure ensures uniform distribution of flame retardant functionality throughout the material, preventing leaching and maintaining both adhesion and mechanical properties while reducing hazardous substance levels.

Inventive Principle:

Principle #40Composite materials

3Reliability

If high loading levels of metal hydroxides or zinc borates are added, then flammability tests are passed, but adhesion and mechanical properties deteriorate

Engineering Contradiction:

Improveflammability test performanceVSAvoidadhesion and mechanical properties

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the concentration parameter by incorporating phosphate-containing groups at lower loading levels compared to traditional metal hydroxides or zinc borates. The phosphate groups provide efficient flame retardation through chemical mechanisms, allowing reduced concentrations that do not compromise adhesion or mechanical properties while still passing flammability tests.

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 method provides a flame retardant copolymer with improved adhesion and mechanical properties, as the phosphate groups are covalently bonded, preventing leaching and maintaining adhesive strength.

Implementation Method 1

reacting the epoxy group of the epoxy-functionalized phosphate compound with the pendent carboxylic acid group of the precursor (meth)acrylate copolymer to form the (meth)acrylate copolymer having the pendent phosphate-containing group

Methodology Applied

Scientific EffectCovalent bonding: Chemical Bonding

Data Source

PatentEP4423149B1Flame retardant pressure-sensitive adhesive and method of making

Publication Date: 2025.11.26 3M INNOVATIVE PROPERTIES CO

AI summary

A method of making a (meth)acrylate copolymer having pendent phosphate-containing groups and a pressure-sensitive adhesive that contains the (meth)acrylate copolymer having pendent phosphate-containing groups are provided. The method includes reacting a precursor (meth)acrylate copolymer having pendent carboxylic acid groups with an epoxy-functionalized phosphate compound. The pendent phosphate-containing groups on the reaction product can function as a flame retardant for the pressure-sensitive adhesive.