Cured Rubber Sheet Particulate Removal via Coating Segmentation
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Solution Overview
Problem
The presence of dusting agents or particulates on EPDM rubber sheets interferes with adhesion during the manufacturing and installation of roofing membranes, requiring additional steps to remove them and complicating the application of adhesives and fabric backings.
Innovation Solution
A process involving the application of a curable coating composition on one surface of an uncured rubber sheet, which is then cured before rolling and further curing, resulting in a particulate-free cured rubber sheet that can be easily unwound and fabricated into roofing membranes without adhesion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dusting agent is applied to the uncured rubber sheet to prevent blocking during rolling and curing, then the rubber sheet can be successfully cured without sticking, but surface particulates are introduced that interfere with subsequent adhesion operations
Solution Approach 1:
The process segments the curing operation into two distinct phases: first curing the coating composition to form a release layer, then curing the rubber sheet itself. This segmentation allows the release function to be performed by the cured coating layer without requiring dusting agents on the final product surface.
Solution Approach 2:
The coating composition is applied and cured on the uncured rubber sheet before the rubber curing operation. This preliminary action creates a cured release layer that prevents blocking during rolling and curing, eliminating the need for dusting agents that would otherwise be required.
Solution Approach 3:
The cured coating composition acts as an intermediary layer between the uncured rubber sheet and the rolling/curing process. This intermediate layer provides the release function during curing, allowing the rubber to be cured without blocking while leaving no harmful particulates on the final surface.
2Ease of manufacture
If additional steps are taken to remove the dusting agent before adhesive application, then proper adhesion can be achieved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The invention extracts the release function from the dusting agent and transfers it to a cured coating composition layer. This extraction eliminates the need for dusting agents entirely, removing the problematic particulates before they can interfere with adhesion operations.
Solution Approach 2:
The invention changes the state of the coating composition from uncured to cured, creating a cured release layer that provides the necessary release function during rubber curing. This parameter change (from uncured to cured) allows the coating to serve as an effective release agent without leaving interfering particulates.
3Ease of manufacture
If thick layers or multiple layers of adhesive are used to overcome the dusting agent interference, then adhesion can be achieved, but material consumption increases and the system becomes more complex
Solution Approach 1:
The invention converts the potentially harmful effect of the cured coating layer (which could act as a barrier to adhesion) into a beneficial release function during curing. The cured coating layer provides release during the rubber curing process while maintaining a clean surface for subsequent adhesion operations.
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 process produces a rubber sheet that is substantially free of surface particulates, allowing for efficient adhesion and modification, such as the application of fabric backings or pressure-sensitive adhesives, without additional measures, and enables seamless installation and seaming of roofing membranes.
Implementation Method 1
The coating composition may be a UV-curable coating composition. The cured coating layer may be formed by exposing the coating composition to a UV light source.
Implementation Method 2
uncured sheets, also referred to as green membranes, are rolled and placed into a curing oven to effect vulcanization of the rubber
Data Source
AI summary
A method for making a cured rubber sheet, the method comprising providing an uncured rubber sheet, where the uncured rubber sheet includes opposing planar surfaces, applying a curable coating composition to one planar surface of the sheet to form a layer of curable coating composition, subjecting the curable coating composition to curing conditions that cure the coating composition and thereby form a cured coating layer on the uncured rubber sheet, rolling the uncured rubber sheet having a cured coating layer onto itself to form a roll, and subjecting the roll to curing conditions that cure the uncured rubber sheet and thereby forms a roll of cured rubber sheet.