High Shear Polymer-Binder Composite Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing polymer-bituminous binder composites are limited by long processing times, low polymer concentrations, instability at normal temperatures, and inefficiencies in handling high molecular weight polymers, which restrict their use in applications like road construction and roofing.
Innovation Solution
A high shear and high pressure method using an extruder or roll mill to mix polymers with bituminous binders, achieving polymer concentrations greater than 50% and producing stable pellets that can be stored and transported at normal temperatures, allowing for instant solubility when mixed with additional binders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional low shear mixing methods are used to produce polymer-bituminous binder composites, then the processing time is long (several hours), but the polymer concentration remains low (typically less than 10 wt.%)
Solution Approach 1:
The invention changes the mixing parameters by using high shear mixing (shear rates of 100-1000 s^-1) and elevated temperatures (150-250°C) instead of conventional low shear mixing. This parameter change enables rapid dispersion of high molecular weight polymers at concentrations greater than 50 wt.% in bituminous binders within minutes, resolving the contradiction between achieving high polymer concentration and maintaining long processing times.
2Reliability
If high molecular weight polymers are used to enhance rheological properties, then the elasticity and plasticity improve, but the handling and mixing become difficult
Solution Approach 1:
The invention uses elevated temperatures (150-250°C) during mixing to reduce the viscosity of high molecular weight polymers, making them easier to handle and mix. The high shear mixing further aids in dispersing these polymers. After mixing, the composite is cooled to ambient temperature where it maintains stable, solid form with enhanced rheological properties, thus resolving the contradiction between improved rheology and ease of manufacture.
Solution Approach 2:
The invention exploits phase transitions by mixing polymers at elevated temperatures where they are in a molten, easily mixable state, then cooling the composite to ambient temperature where it solidifies into a stable, handleable form. This phase transition approach allows high molecular weight polymers to be processed easily during manufacturing while maintaining their superior rheological properties in the final product.
3Reliability
If polymer-bituminous binder composites are produced with high polymer content, then the performance characteristics improve, but the stability at normal temperatures deteriorates
Solution Approach 1:
The invention uses phase transitions to resolve this contradiction. The high polymer content composite is mixed and processed at elevated temperatures (150-250°C) where it remains fluid and homogeneous. Upon cooling to ambient temperature, the composite solidifies into a stable form that maintains its composition and prevents phase separation. This phase transition approach allows the composite to achieve both high polymer content for improved performance and stability at normal temperatures.
4Productivity
If conventional mixing methods are used, then the equipment complexity is low, but the productivity and polymer concentration remain limited
Solution Approach 1:
The invention uses high shear mixing equipment that operates at elevated temperatures and high shear rates. This equipment, while more complex than conventional mixers, enables rapid mixing (within minutes) and achieves high polymer concentrations (greater than 50 wt.%) that are not possible with simple mixers. The increased device complexity is justified by the significant improvement in productivity and polymer concentration.
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
This method significantly reduces production time, increases polymer concentration, stabilizes the composite at ambient temperatures, and enhances rheological properties, reducing costs and improving handling and storage of the polymer-bituminous binder composite.
Implementation Method 1
A high shear and high pressure method using an extruder or roll mill to mix polymers with bituminous binders
Implementation Method 2
A high shear and high pressure method using an extruder or roll mill to mix polymers with bituminous binders
Data Source
AI summary
A method of making a polymer-binder composite, and the composite thus created. The method employs a high shear device that mixes together polymer with binder, and optionally with additive. The mixing is accomplished in less than one hour, less than 30 minutes or less than 3 minutes, and done at high shear rates. The shear conditions are defined by scalar shear quantity greater than 250, 1,000 or 1,500, resident time of greater than 0.05, 0.10 or 0.20 seconds, and energy utilized per unit mass of greater than 0.05, 0.10 or 0.20 kW/kg. The composite thus produced can be made with a high percentage of polymers. It can be cooled and cut into pellets that are dry and stable at normal temperatures and which can be stored or transported without heating to secondary mixing locations. The composite pellets are quickly soluble in the additional binder.