Die Coating High Viscosity Materials Using Heated Extrusion
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Solution Overview
Problem
Traditional asphalt coating techniques are ineffective for applying high viscosity non-asphaltic materials at typical shingle manufacturing line speeds, failing to control the characteristics and quality of the resulting coating.
Innovation Solution
A method and apparatus that involve heating and mixing high viscosity non-asphaltic materials in a mix tank, circulating them through a loop with controlled pressure, and using a second pump to apply the material to a moving substrate via an extrusion die, with the pumping speed adjusted based on the substrate's line speed to maintain coating quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional asphalt coating techniques are used, then coating process is simple and equipment is conventional, but the technique is ineffective for high viscosity non-asphaltic materials at manufacturing line speeds
Solution Approach 1:
The system changes the physical parameters of the coating material by heating it to reduce viscosity, making it suitable for extrusion at high manufacturing line speeds. The heating system maintains the material at optimal temperature throughout the extrusion process, ensuring consistent flow properties and coating quality at elevated production speeds
Solution Approach 2:
The invention replaces traditional mechanical coating methods (brushes, rollers, spray) with a heating and extrusion system. The material is heated to reduce viscosity, then forced through a die at controlled rates, substituting mechanical application with a thermally-assisted extrusion process that works effectively at high line speeds
2Productivity
If high viscosity non-asphaltic materials are applied at high manufacturing line speeds, then productivity increases, but control over coating characteristics and quality deteriorates
Solution Approach 1:
The system incorporates feedback control through variable speed drives on the extrusion pump and heating system. The pump speed is adjusted based on real-time monitoring of coating application rate and substrate speed, while the heating system responds to maintain optimal material temperature. This closed-loop control ensures consistent coating thickness and quality even at varying high production speeds
Solution Approach 2:
The system uses dynamic adjustment of extrusion parameters including variable pump speed, adjustable heating zones, and controllable die pressure. These dynamic controls allow the system to adapt to changes in substrate speed and material properties, maintaining precise coating characteristics throughout the manufacturing process at high line speeds
3Manufacturing precision
If high viscosity materials are heated and circulated through a loop with controlled pressure, then coating quality is improved, but device complexity increases
Solution Approach 1:
The system divides the coating process into distinct functional segments: a heating zone to reduce viscosity, a circulation loop for material distribution, a pressure control system for regulated flow, and an extrusion die for application. Each segment is independently controlled and optimized, allowing complex functions to be managed through modular, manageable components rather than a single complicated system
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
Enables efficient application of high viscosity non-asphaltic materials at traditional and higher manufacturing line speeds, ensuring controlled characteristics and quality of the coating, suitable for roofing products like glass mat shingles.
Implementation Method 1
heating and mixing a coating material in a mix tank
Implementation Method 2
pumping the heated and mixed material around a circulation loop from the mix tank; through the circulation loop, and back to the mix tank with a first pump
Implementation Method 3
maintaining a predetermined pressure of the heated and mixed material within the circulation loop
Implementation Method 4
extracting part of the heated and mixed material from the circulation loop with a second pump; delivering the extracted part of the heated and mixed material to a die with the second pump
Implementation Method 5
applying the extracted part of the heated and mixed material to the moving substrate with the die
Data Source
AI summary
A method is disclosed for die coating a moving substrate with a high viscosity material such as a polymer. The method includes heating and mixing ingredients to form a homogenous mixture, pumping the mixture around a circulation loop with a first pump, maintaining a predetermined pressure of the mixture within the circulation loop, drawing mixture from the circulation loop with a second pump, delivering the mixture using the second pump to an extrusion die adjacent the moving substrate to coat the substrate, and controlling the second pump as a function of at least the speed of the moving substrate to maintain predetermined characteristics of the coating mixture applied to the moving substrate. An apparatus for carrying out the method also is disclosed.