Bitumen composition comprising degraded waste rubber material
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Solution Overview
Problem
The high cost and environmental concerns associated with using chemical devulcanization agents in polymer-modified bitumen compositions, combined with the challenge of maintaining rheological and mechanical properties while reducing the amount of styrene block copolymers and increasing the content of waste rubber material, which increases viscosity and limits processing.
Innovation Solution
A bitumen composition comprising a bitumen base, a reduced amount of elastomer or plastomer, and a degraded waste rubber material, where the degradation is achieved through thermomechanical devulcanization or depolymerization in the absence of chemical agents, resulting in a composition with improved processability and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If waste rubber material is used to substitute styrene block copolymers in bitumen compositions, then production cost is reduced, but viscosity of the bitumen composition increases significantly
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of waste rubber through devulcanization, reducing crosslinking density and molecular weight. This transforms the rubber from a high-viscosity state to a lower-viscosity state that can be processed in bitumen while maintaining substitution benefits
Solution Approach 2:
The patent applies preliminary action by performing devulcanization treatment on waste rubber before incorporating it into bitumen compositions. This pre-treatment reduces the rubber's viscosity and crosslinking in advance, enabling successful mixing and processing without the harmful viscosity increase that would occur with untreated waste rubber
2Ease of manufacture
If chemical devulcanization agents are used to process waste rubber, then waste rubber can be incorporated into bitumen, but production cost increases and environmental harm occurs
Solution Approach 1:
The patent replaces chemical devulcanization systems with a mechanical/thermal system. By applying mechanical shear force and thermal energy during mixing and processing, the rubber is devulcanized without chemical agents, eliminating the associated costs and environmental harm while achieving the same processability benefits
Solution Approach 2:
The patent applies self-service by enabling the waste rubber to undergo devulcanization through the inherent thermal and mechanical conditions of the bitumen mixing process itself, rather than requiring separate chemical treatment steps. The system uses its own processing energy to achieve the necessary rubber modification
3Quantity of substance
If high amounts of waste rubber material are used in bitumen composition, then substitution of expensive polymers is achieved, but processing becomes impossible due to excessive viscosity
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight and crosslinking density of the waste rubber through devulcanization. This transforms the rubber's rheological properties, enabling high amounts to be used in the composition without causing excessive viscosity that would prevent processing
Solution Approach 2:
The patent applies preliminary action by pre-devulcanizing the waste rubber before incorporation into bitumen. This advance treatment ensures the rubber has appropriate viscosity characteristics for mixing and processing, allowing high substitution levels to be achieved without compromising ease of operation
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 solution allows for a significant reduction in the amount of expensive elastomers or plastomers while maintaining the mechanical and rheological properties of polymer-modified bitumen compositions, reducing production costs and environmental impact, and ensuring low viscosity even at high waste rubber content.
Implementation Method 1
The term 'devulcanization' as used herein refers to a chemical process in which crosslinking of a vulcanized rubber material is reduced
Implementation Method 2
The term 'depolymerization' as used herein refers to a chemical process in which a polymer is converted into monomers or oligomers
Data Source
AI summary
The present invention relates to a degraded waste rubber material, bitumen compositions comprising said degraded waste rubber material, and the use of such bitumen compositions.