Polymer Modified Bitumen With Isocyanate Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polymer modified bitumens face issues with high viscosity and lack of high-temperature storage stability, limiting their application in road and bridge pavements due to the use of unprocessed rubber granulate and complex, high-temperature preparation processes.
Innovation Solution
A 3-component system comprising an oil-rubber composition and a crosslinking agent with free isocyanate groups is used to chemically react with bitumen components, forming a polymer network that enhances the stability and elasticity of the bitumen, allowing for the use of up to 15% waste rubber without increasing viscosity significantly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If unprocessed rubber granulate is used as bitumen modifier, then waste rubber recycling is achieved, but viscosity increases significantly above 15% wt addition
Solution Approach 1:
The rubber granulate undergoes preliminary devulcanization treatment before being added to bitumen. This pre-treatment breaks down the crosslinked sulfur bonds in the rubber, reducing its molecular weight and viscosity contribution, thereby enabling higher waste rubber content without excessive viscosity increase
Solution Approach 2:
The invention changes the chemical structure of the rubber modifier by removing sulfur crosslinks through devulcanization. This parameter change in the rubber's molecular structure fundamentally alters its rheological properties when mixed with bitumen, allowing higher concentrations without viscosity penalties
2Loss of substance
If unprocessed rubber granulate is used as bitumen modifier, then waste rubber recycling is achieved, but storage stability at high temperature deteriorates
Solution Approach 1:
The rubber granulate undergoes preliminary devulcanization treatment before being added to bitumen. This pre-treatment breaks down the crosslinked sulfur bonds in the rubber, reducing its molecular weight and viscosity contribution, thereby enabling higher waste rubber content without excessive viscosity increase
Solution Approach 2:
The invention changes the chemical structure of the rubber modifier by removing sulfur crosslinks through devulcanization. This parameter change in the rubber's molecular structure fundamentally alters its rheological properties when mixed with bitumen, allowing higher concentrations without viscosity penalties
3Reliability
If complex high-temperature preparation process is used, then bitumen modification is achieved, but process complexity and energy consumption increase
Solution Approach 1:
The rubber granulate undergoes preliminary devulcanization treatment before being added to bitumen. This pre-treatment breaks down the crosslinked sulfur bonds in the rubber, reducing its molecular weight and viscosity contribution, thereby enabling higher waste rubber content without excessive viscosity increase
Solution Approach 2:
The invention changes the chemical structure of the rubber modifier by removing sulfur crosslinks through devulcanization. This parameter change in the rubber's molecular structure fundamentally alters its rheological properties when mixed with bitumen, allowing higher concentrations without viscosity penalties
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 results in bitumen with improved high-temperature stability, reduced viscosity, and enhanced physico-mechanical properties, enabling its use in road construction and other applications without the limitations of previous technologies.
Implementation Method 1
a crosslinking agent with free isocyanate groups which chemically react with bitumen components, so as to form a polymer network
Implementation Method 2
due to the presence of sulfur in their structure and under their influence, the formation of chemical bonds between rubber granulate and bitumen components occurs
Data Source
AI summary
The invention relates to bitumen modifying agent, polymer modified bitumen, being modified by physical and chemical methods, and the methods for preparation of polymer modified bitumen. Polymer modified bitumen comprises bitumen and oil-rubber composition, obtained by mixing shredded waste rubber with castor oil, and also comprises crosslinking component with reactive isocyanate groups (NCO) in its structure. Polymer modified bitumen contains, calculated on the weight of polymer modified bitumen, bitumen in the amount from 77% wt. to 95% wt. and oil-rubber composition in the amount from 4% wt. to 20% wt., while content of particles of waste rubber is from 4% wt. to 18% wt., while castor oil is from 0,25% wt. to 3% wt.. The polymer modified bitumen additionally comprises crosslinking component in the form of compound with free isocyanate groups (NCO) in the amount from 0,25% wt. to 3% wt.