Roofing Shingle Coating Asphalt via Partial Blowing and Wax
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Solution Overview
Problem
The increasing scarcity and high cost of special grades of asphalt for producing roofing shingle coating asphalts have limited the material options and increased production costs, while conventional processes struggle with using low flashpoint and poor weathering asphalts due to their inability to meet the required properties for roofing shingles.
Innovation Solution
A process involving partial blowing of low flashpoint or poor weathering asphalt feedstocks, combined with the addition of wax, to produce a coating asphalt with specific viscosity, softening point, and penetration ranges, which can be used to create roofing shingles with improved durability and tear resistance, utilizing a partial blowing process and wax addition to achieve the desired properties without extensive energy consumption or emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If special grades of asphalt (roofer's flux) are used as feedstock, then the coating asphalt can be air-blown to achieve desired properties (softening point, penetration, viscosity, durability), but the material options are limited and production costs increase due to scarcity
Solution Approach 1:
The patent changes the key parameter of using non-coating grade asphalts (paving asphalts, distillate blends, crudes) that were previously considered unsuitable. By modifying the feedstock selection criteria and applying controlled air blowing processes, the invention expands material options beyond traditional coating grade asphalts while achieving required coating asphalt properties
Solution Approach 2:
The patent creates composite material systems by blending different types of asphalts (paving grade, distillate, crudes) to produce feedstocks with suitable properties for coating asphalt production. This composite approach allows flexibility in material selection and optimizes performance characteristics
2Reliability
If special grades of asphalt (roofer's flux) are used as feedstock, then the coating asphalt can be air-blown to achieve desired properties, but the production cost increases compared to commodity paving asphalts
Solution Approach 1:
The patent substitutes expensive, scarce coating grade asphalts with cheaper, more abundant commodity asphalts (paving asphalts, distillate blends, crudes). Although these alternative feedstocks have different properties, they can be processed through air blowing to achieve the required coating asphalt performance at lower cost
Solution Approach 2:
The invention changes the economic parameter by redirecting the feedstock source from premium-priced specialty asphalts to commodity-priced asphalts. The process parameters (air blowing conditions, temperature, time) are adjusted to transform the cheaper feedstocks into suitable coating asphalts
3Quantity of substance
If low flashpoint asphalts are used as feedstock, then production cost decreases and material options increase, but the conventional air blowing process cannot safely achieve the required softening point and durability
Solution Approach 1:
The patent changes the process parameters for air blowing when using low flashpoint asphalts. By carefully controlling temperature, oxygen supply, and blow time, the process achieves the required softening point and durability improvements without exceeding the flashpoint limit, thereby maintaining both safety and performance
Solution Approach 2:
The patent applies partial air blowing to low flashpoint asphalts - using less aggressive oxidation than traditional full blowing processes. This partial action is sufficient to achieve the required property improvements while staying within safe temperature limits imposed by the low flashpoint feedstock
4Adaptability or versatility
If poor weathering asphalts are used as feedstock, then material options increase and cost decreases, but the conventional process cannot produce coating asphalt with adequate durability
Solution Approach 1:
The patent changes the feedstock selection parameter to include asphalts with poor inherent weathering characteristics. Through controlled air blowing processes, these asphalts are transformed into coating asphalts with improved durability, thereby expanding material options to include previously unsuitable feedstocks
Solution Approach 2:
The patent uses accelerated oxidation through air blowing to fundamentally improve the weathering resistance of poor weathering asphalts. The oxidation process modifies the chemical structure of the asphalt, creating a more durable coating asphalt from an initially poor weathering feedstock
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 process allows the use of cost-effective and readily available low flashpoint and poor weathering asphalts to produce roofing shingles with enhanced weatherability and tear resistance, meeting or exceeding industry specifications for softening point, penetration, and durability, thus expanding material options and reducing production costs.
Implementation Method 1
an asphalt feedstock which has a low flashpoint... is partially blown
Implementation Method 2
Wax is added to the asphalt feedstock. The process produces a coating asphalt having a low melt viscosity within a range of from about 50 cps to about 150 cps at 400° F.
Data Source
AI summary
In a process of producing a roofing shingle coating asphalt from a low flashpoint asphalt feedstock, an asphalt feedstock which has a low flashpoint of from 490° F. (254° C.) to 540° F. (282° C.) is partially blown, and wax is added to the asphalt feedstock. The process produces a coating asphalt having a low melt viscosity of from 50 cps to 150 cps at 400° F. (204° C.), a softening point of from 190° F. (88° C.) to 235° F. (113° C.) and a penetration of at least 15 dmm at 77° F. (25° C.). In another embodiment, the process produces a roofing shingle coating asphalt having good weatherability from a poor weathering asphalt feedstock. In a further embodiment, the process produces roofing shingles including a filled coating containing a poor tear filler without sacrificing the tear strength of the shingles.