Local Polymer Concentration Asphalt Shingle Coatings
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Solution Overview
Problem
Existing methods for incorporating cross-linked tire rubber and polymers into bitumen face challenges such as inconsistent dissolution, leading to blockages and inferior pavement systems, and existing solutions do not effectively control local polymer concentrations for improved impact resistance in asphalt shingle coatings.
Innovation Solution
A method for generating local polymer concentration (LPC) asphalt shingle coatings involves heating bitumen and sulfur cross-linking agents with styrene ethylene butadiene styrene (SEBS) polymers to create cross-linked gels, which are then blended to achieve controlled polymer microstructures, enhancing impact resistance and flow properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cross-linked tire rubber and polymers are incorporated into bitumen, then impact resistance is improved, but inconsistent dissolution occurs leading to blockages and inferior pavement systems
Solution Approach 1:
The patent applies preliminary action by pre-mixing the polymers and tire rubber with bitumen at controlled temperatures and shear rates before final application. This preliminary mixing ensures proper dissolution and distribution of the cross-linked components, preventing blockages and inconsistent dissolution during subsequent processing while maintaining impact resistance properties
Solution Approach 2:
The patent utilizes parameter changes by controlling temperature, shear rate, and mixing time during the incorporation process. By optimizing these parameters, the patent achieves consistent dissolution of cross-linked tire rubber and polymers in bitumen, eliminating blockages while preserving the impact resistance enhancement
2Duration of action of stationary object
If high concentrations of polymer elastomers are incorporated to improve impact resistance, then durability is enhanced, but the mixture becomes too viscous for practical application
Solution Approach 1:
The patent applies partial action by incorporating polymer elastomers at optimized concentrations rather than maximum possible concentrations. This approach achieves sufficient durability enhancement while maintaining the mixture viscosity within practical application ranges, avoiding the excessive viscosity that would result from higher polymer loadings
Solution Approach 2:
The patent utilizes parameter changes by adjusting temperature and shear rate during mixing to control the viscosity of high polymer concentration mixtures. By optimizing these parameters, the patent enables practical application of durable, high-performance asphalt compositions that would otherwise be too viscous for conventional application methods
3Manufacturing precision
If mixing temperature is increased to improve polymer dissolution, then dissolution rate increases, but tire rubber degrades and aromatic oils evaporate
Solution Approach 1:
The patent applies preliminary action by conducting dissolution at moderate temperatures followed by a separate cross-linking step. This two-stage approach ensures complete polymer dissolution without exposing the tire rubber and aromatic oils to excessive temperatures that would cause degradation and evaporation
Solution Approach 2:
The patent utilizes parameter changes by implementing a two-stage temperature profile: first dissolving polymers at moderate temperatures (300-400°F) to ensure complete dissolution, then increasing temperature (400-500°F) for cross-linking. This controlled parameter change achieves dissolution completeness while minimizing material degradation and evaporation losses
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 produces Class 4 impact-resistant shingle sheets capable of withstanding high winds and hail impacts, with improved adhesion and durability in various asphalt applications, including roofing and pavement systems.
Implementation Method 1
heating bitumen and sulfur cross-linking agents with styrene ethylene butadiene styrene (SEBS) polymers to create cross-linked gels
Implementation Method 2
heating bitumen and sulfur cross-linking agents with styrene ethylene butadiene styrene (SEBS) polymers
Data Source
AI summary
A method for generating a local polymer concentration (“LPC”) asphalt shingle coating is described. The method includes receiving a plurality of saturated polymer (“SP”) premix components including a rapid digestion process (“RDP”) compound and a sulfur cross-linking agent. The RDP compound is one or more of an unmodified RDP compound, a modified RDP compound, an enhanced RDP compound, and a modified enhanced RDP compound. The SP premix components are then heated in the first vessel to 320-500° F. and mixed for 15-60 minutes to generate a SP premix. The method also includes receiving an asphalt feedstock and a cross-linking polymer in a second vessel. The asphalt feedstock and cross-linking polymer are heated in the second vessel to 320-500° F. and mixed for 1-60 minutes to generate a LPC premix. The method proceeds by receiving the SP premix and the LPC premix in a third vessel and heating the SP premix and LPC premix to 320-500° F. with mixing for 30-240 minutes to generate the LPC asphalt shingle coating.