Phosphate Esters as Bitumen Adhesion Promoters

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing asphalt compositions face challenges in achieving strong adhesion between bitumen and aggregates, particularly acidic and basic aggregates, due to the hydrophobic nature of bitumen and the polar nature of water, leading to issues like water damage, rutting, and loss of structural strength in pavements.

Innovation Solution

The use of phosphate esters, formed from polyhydric alcohols esterified with carboxylic acids and reacted with phosphatising agents, serves as an effective adhesion promoter to enhance the bonding between bitumen and aggregates, improving both passive and active adhesion and resisting water displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If bitumen is used as a binder, then it provides binding between aggregates, but it has poor adhesion to hydrophilic aggregate surfaces due to its hydrophobic nature

Engineering Contradiction:

Improveadhesion strength between bitumen and aggregateVSAvoidwater displacement and penetration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces phosphated compounds as intermediary substances that modify the bitumen's surface properties. These compounds contain both hydrophobic regions (to interact with bitumen) and hydrophilic regions (to interact with aggregate surfaces), acting as a bridge between the incompatible hydrophobic bitumen and hydrophilic aggregate surfaces, thereby improving adhesion and resisting water displacement

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical and physical parameters of bitumen by adding phosphated compounds. This changes the surface polarity and interfacial tension characteristics of the bitumen, enabling it to better interact with hydrophilic aggregate surfaces while maintaining its binding properties

Inventive Principle:

Principle #35Parameter changes

2Reliability

If water penetrates the bitumen film, then adhesion is lost and structural strength decreases, but preventing water penetration requires improved adhesion promoters

Engineering Contradiction:

Improveresistance to water damageVSAvoidcomposition complexity with phosphated compounds

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Phosphated compounds serve as intermediary agents that create a protective interface between bitumen and water. They modify the bitumen film's properties to be more water-resistant while maintaining aggregate adhesion, thereby preventing water penetration and the associated damage without requiring overly complex formulations

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If adhesion promoters are added to improve bitumen-aggregate bonding, then adhesion increases, but the effectiveness varies with aggregate type (acidic vs basic)

Engineering Contradiction:

Improveadhesion across different aggregate typesVSAvoiduniversality towards acidic and basic aggregates

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The phosphated compounds described in the patent possess multi-functional properties that enable them to effectively promote adhesion to both acidic and basic aggregate types. The molecular structure contains functional groups that can interact with different surface chemistries, providing universal effectiveness across various aggregate types without requiring separate additives for each type

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 phosphate esters significantly increase the adhesion of bitumen to a wide range of aggregates, including granite and limestone, thereby improving the durability and resistance to water damage of asphalt pavements, with a favorable environmental profile and thermal stability.

Implementation Method 1

adhesion promoter to alter the relative surface properties and polarity of incompatible materials, thus facilitating a strong bond between the bitumen and the aggregate

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

alter the relative surface properties and polarity of incompatible materials, thus facilitating a strong bond

Methodology Applied

Scientific EffectSurface tension modification: Surface Tension

Implementation Method 3

Active adhesion is achieved by the action of the adhesion promoter to decrease the contact angle of the bitumen to aggregate interface, thus allowing the bitumen to displace water and coat the aggregate surface

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentEP2914665B1Phosphated compounds as adhesion promoters

Publication Date: 2019.01.02 AKZO NOBEL CHEMICALS INTERNATIONAL BV

AI summary

A bitumen containing composition is provided, comprising bitumen and a phosphate compound, which is obtainable by the esterification of a polyhydric alcohol having at least three hydroxyl groups, with a carboxylic acid having 8-24 carbon atoms, preferably 12-22 carbon atoms, or a derivative thereof, wherein at least one but not all of the hydroxyl groups are esterified, provided that when the polyhydric alcohol has 5 or more hydroxyl groups then at least two but not all of the hydroxyl groups are esterified, followed by reacting the ester obtained with a phosphatising reagent; wherein the said composition is not a bitumen-in-water emulsion.