Crumb Rubber Bitumen Odor Reduction via Aldehyde Mediators
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Solution Overview
Problem
Crumb rubber modified bitumen emits foul odors during processing due to the release of volatile substances like sulfur and nitrogen compounds at high temperatures, necessitating a method to reduce these odors in industrial applications.
Innovation Solution
Admixing active agents comprising aldehydes, alcohols, terpenes, ketones, and carbonic acid esters with a diluting agent to liquid crumb rubber modified bitumen, specifically using alpha-hexyl cinnamaldehyde, 2-(4-tert.-butylbenzyl) propionaldehyde, 2-benzylidenheptanal, and other compounds, along with mineral or vegetable oils, to reduce odor emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crumb rubber modified bitumen is processed at high temperatures above 100°C, then the bitumen becomes suitable for industrial applications such as road surfacing and roofing materials, but volatile substances including sulfur and nitrogen compounds are released causing foul odors
Solution Approach 1:
The patent introduces active agents as intermediary substances that chemically interact with the volatile sulfur and nitrogen compounds released during high-temperature processing. These active agents neutralize the harmful volatile substances, converting them into less odorous compounds while allowing the bitumen to be processed at necessary high temperatures for industrial applications
2Reliability
If crumb rubber is incorporated into bitumen to improve sustainability and material properties, then tire disposal is reduced and bitumen performance is enhanced, but odor problems are exacerbated during high-temperature processing
Solution Approach 1:
Active agents are introduced as mediators that specifically target and neutralize the volatile compounds generated from crumb rubber decomposition. These agents enable the continued use of crumb rubber modified bitumen for its sustainability and performance benefits while mitigating the odor issue through chemical interaction with the harmful volatile substances
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
Significantly reduces odor emissions during processing, making the bitumen suitable for use in road surfacing, insulating layers, and roofing materials by minimizing volatile compound release, as demonstrated by the addition of specific active agent mixtures at elevated temperatures.
Implementation Method 1
admixing active agents and a diluting agent to liquid crumb rubber modified bitumen... volatile substances present in CRMB may be released to the air. Especially sulfur and nitrogen compounds may lead to foul odors
Data Source
AI summary
A method for reducing odors including the steps of admixing active agents and a diluting agent to liquid crumb rubber modified bitumen, wherein the active agents comprise 20 to 60 wt.-% of an aldehyde selected from alpha-hexyl cinnamaldehyde, 2-(4-tert.-butylbenzyl) propionaldehyde, 2-benzylidenheptanal, or mixtures thereof, and 10 to 40 wt.-% of one or more alcohols having a boiling point of at least 150° C., calculated on the total weight of active agents. A crumb rubber modified bitumen composition as obtained by the method above. The use of a crumb rubber modified bitumen composition as obtained by the method above in road surfacing and road base materials, in insulating layers for buildings, in roofing materials and/or in sealing sheeting.