Vacuum assisted slot die coating techniques
First Claim
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1. A method for applying a wet film to a substrate, comprising:
- applying a coating material at a discharge rate about 2 ml/min to about 20 ml/min from a discharge end of a slot die onto a moving web of said substrate at a moving rate of about 10.0 m/min to about 45.0 m/min to form said wet film on said substrate, said wet film including a width and a thickness relative to said substrate, wherein said discharge end of said slot die comprises an upstream bar and a downstream bar each bar having an essentially planar land surface facing said moving web, and wherein a constant coating gap of about 40 μ
m to about 450 μ
m is maintained between said discharge end of said slot die and said moving web;
applying a vacuum force adjacent said discharge end of said slot die, wherein said vacuum force creates a pressure differential between an upstream side of said discharge end and a downstream side of said discharge end, and wherein said pressure differential is between about 1 inch of H20 and about 10 inches of H20; and
adjusting said vacuum force in real-time while applying said coating material to control said width and thickness of said wet film.
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Abstract
Systems, apparatuses, techniques and processes for applying a wet film to a substrate using a slot die are provided. In one form, the air pressure around at least a portion of the discharge end of the slot die is adjustable by the application of a vacuum force in order to control the width and thickness of the wet film being applied to the substrate. In one aspect of this form, the wet film is a narrow, continuous stripe of reagent material applied to a moving web of the substrate from which a plurality of test elements will be obtained. However, different forms and applications are also envisioned.
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Citations
18 Claims
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1. A method for applying a wet film to a substrate, comprising:
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applying a coating material at a discharge rate about 2 ml/min to about 20 ml/min from a discharge end of a slot die onto a moving web of said substrate at a moving rate of about 10.0 m/min to about 45.0 m/min to form said wet film on said substrate, said wet film including a width and a thickness relative to said substrate, wherein said discharge end of said slot die comprises an upstream bar and a downstream bar each bar having an essentially planar land surface facing said moving web, and wherein a constant coating gap of about 40 μ
m to about 450 μ
m is maintained between said discharge end of said slot die and said moving web;applying a vacuum force adjacent said discharge end of said slot die, wherein said vacuum force creates a pressure differential between an upstream side of said discharge end and a downstream side of said discharge end, and wherein said pressure differential is between about 1 inch of H20 and about 10 inches of H20; and adjusting said vacuum force in real-time while applying said coating material to control said width and thickness of said wet film. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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2. A method for applying a wet film to a substrate, comprising:
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applying a coating material at a discharge rate about 2 ml/min to about 20 ml/min from a discharge end of a slot die onto a moving web of said substrate at a moving rate of about 10.0 m/min to about 45.0 m/min to form said wet film on said substrate, said wet film including a width and a thickness relative to said substrate, wherein said discharge end of said slot die comprises an upstream bar and a downstream bar, each bar having an essentially planar land surface facing said moving web, and wherein a constant coating gap of about 40 μ
m to about 450 μ
m is maintained between said discharge end of said slot die and said moving web;applying a vacuum force adjacent said discharge end of said slot die, wherein said vacuum force creates a pressure differential between an upstream side of said discharge end and a downstream side of said discharge end, and wherein said pressure differential is between about 1 inch of H20 and about 10 inches of H20; adjusting said vacuum force in real-time while applying said coating material to control said width and thickness of said wet film; and sensing said width of said wet film, and wherein adjusting said vacuum force is performed in response to determining said width corresponds to a value other than a predetermined value. - View Dependent Claims (3, 4, 5, 6)
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Specification