Method and apparatus for die coating a substrate with high viscosity materials
AssigneeBuilding Materials Investment Corporation
InventorJames A. Svec
Life of this patent
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Abstract
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.
Claims19
A method comprising the steps of:
- moving a substrate along a processing path at a line speed;
- mixing a viscous material having a viscosity of 10,000 cP to 20,000 cP at 375° Fahrenheit in a tank to obtain a mixture;
- pumping the mixture from the tank, through a circulation loop, and back to the tank using a first pump;
- controlling a pressure in the circulation loop as the mixture is circulated through the circulation loop;
- extracting at least part of the mixture from the circulation loop using a second pump coupled to the circulation loop;
- using the second pump, pumping the at least part of the mixture through an extrusion die and onto the substrate;
- and
- controlling the pumping of the at least part of the mixture by the second pump based, at least in part, on the line speed of the substrate so that a coating of the mixture is deposited onto the substrate by the extrusion die as the substrate is moved along the processing path at the line speed.
An apparatus, comprising:
- a conveyor configured to move a substrate along a processing path at a line speed;
- a melt tank for containing, melting, and mixing a high viscosity material to obtain a mixture;
- wherein the high viscosity material has a viscosity of 10,000 cP to 20,000 cP at 375° Fahrenheit;
- a circulation loop coupled to the melt tank for circulation of the mixture from the melt tank, through the circulation loop, and back to the melt tank;
- a first pump coupled to the circulation loop and configured for circulating the mixture through the circulation loop;
- a pressure control device in the circulation loop, the pressure control device configured to maintain a predetermined pressure of the mixture within the circulation loop;
- a second pump coupled to the circulation loop, the second pump configured to extract part of the mixture from the circulation loop;
- an extrusion die coupled to the second pump for delivering the part of the mixture extracted from the circulation loop by the second pump onto the substrate as the substrate is moved along the processing path;
- and
- a controller configured to control the second pump as a function at least of the line speed of the substrate moving along the processing path so that a coating of the mixture is deposited by the extrusion die onto the substrate as the substrate is moved along processing path at the line speed.
Dependencies are inferred from the claim text.