Continuous EPDM Membrane Curing via Vacuum Mixing and Hot Air
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Batch processes for manufacturing EPDM roofing membranes are time-consuming, labor-intensive, and costly, leading to inefficiencies in production and increased costs.
Innovation Solution
A continuous manufacturing method involving a planetary mixing extruder that subjects a vulcanizable rubber composition to reduced pressure, followed by extrusion and calendering to form a green membrane, which is then cured using a hot air conveyor system without the need for elevated pressures, reducing processing time to under 2 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If batch processes are used for mixing and curing EPDM rubber composition, then product quality can be maintained, but production time is extended and manufacturing efficiency is reduced
Solution Approach 1:
The patent implements continuous mixing of rubber composition through an extruder and continuous curing through a curing zone, eliminating the batch process interruptions. The rubber composition is continuously fed, mixed, extruded, and cured in an uninterrupted flow, maintaining quality while dramatically increasing production efficiency and reducing manufacturing time.
Solution Approach 2:
The patent applies vacuum treatment to the rubber composition before extrusion to remove entrapped air and volatiles. This preliminary action prevents void formation during subsequent extrusion and curing, ensuring high-quality void-free membranes while enabling continuous processing without defects.
2Reliability
If batch curing in ovens is used, then thorough curing can be achieved, but production costs increase and processing time is extended
Solution Approach 1:
The patent employs continuous curing where the extruded rubber membrane passes through a curing zone with controlled temperature and vacuum conditions. This continuous curing process achieves thorough curing comparable to batch ovens but without the extended processing times and associated costs of batch operations.
Solution Approach 2:
The patent uses vacuum pressure applied during the curing process to remove entrapped air and volatiles from the membrane. This pneumatic approach ensures complete curing and void-free structure while reducing processing time compared to conventional batch oven curing.
3Device complexity
If conventional extrusion without vacuum treatment is used, then processing is simpler, but voids and air entrapment occur in the membrane
Solution Approach 1:
The patent applies vacuum treatment to the rubber composition before and during extrusion to remove entrapped air and volatiles. This preliminary vacuum action prevents void formation in the final membrane, achieving uniform high-quality products. The vacuum system is integrated into the extrusion process, adding minimal complexity while dramatically improving membrane uniformity.
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 results in high-quality, void-free membranes with reduced production time and costs, improving manufacturing efficiency and membrane quality while eliminating the need for batch curing ovens.
Implementation Method 1
subjecting the vulcanizable rubber composition to a reduced pressure within the mixing extruder
Implementation Method 2
applying energy to the green membrane to form a cured membrane
Data Source
AI summary
A method of continuously manufacturing a cured membrane includes continuously compounding and mixing a vulcanizable rubber composition in a mixing extruder while continuously removing gasses from the vulcanizable rubber composition during mixing with a vacuum. The vulcanizable rubber composition may be continuously extruded to form an extrudate, which may be continuously calendered to form a green membrane. The green membrane may be continuously cured, such as by a hot air conveyor curing system, to form a cured membrane.