Multiple coating of fibers
AssigneeAT&T Bell Laboratories
InventorCarl R. Taylor
Life of this patent
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Abstract
Fibers are coated with two (or more) layers. A first coating liquid is applied by an applicator having a die that provides for the formation of a gap between the die and the first coated layer. A second die is located at the exit of the first die, with the second coating liquid flowing onto the fiber through a relatively narrow clearance between the first and second dies. The clearance is formed by die surfaces perpendicular to the fiber axis. This second die also provides for a gap, so that the second layer is applied at a "free surface" at the point of contact with the first coated layer. This approach eliminates turbulence and coating nonuniformities associated with prior art multiple coating techniques.
Claims14
A method of making a coated fiber characterized by passing a fiber through a first coating die that confines a first coating liquid around the fiber and thereafter passing said fiber through a second die, with a second coating liquid being applied onto said first coating liquid through a clearance between said first and second dies that is sufficiently small so that substantially no recirculation of said second coating liquid occurs in the immediate vicinity of the point of application to the first coating liquid, and wherein a gap forms between said second coating liquid and the aperture of said second die.
Dependencies are inferred from the claim text.