Abstract:
A die coating method and apparatus includes a die (40) having an upstream bar (64) with an upstream lip (60) and a downstream bar (66) with a downstream lip (62). The upstream lip (60) is formed as a land (68) and the downstream lip (62) is formed as a sharp edge (70). The shape of the land conforms to the shape of the surface being coated. Changing at least one of the slot height H, the overbite O, and the convergence C can improve coating performance. A replaceable, flexible strip (350) can be used above the coating slot to facilitate replacement of a damaged overbite edge. A low surface energy coating can be applied to the downstream bar and land surfaces.
Abstract:
A die coating method and apparatus includes a die (100, 150, 220) having an upstream bar (104, 154, 226) with an upstream lip, a central bar, a downstream bar (108, 158, 232) with a downstream lip, and a vacuum bar (110, 160, 224). The upstream lip is formed as a land and the first manifold bar is formed as a sharp edge. The shape of the land conforms to the shape of the surface being coated. Changing at least one of the slot heights H, the overbites O, and the convergence C can improve coating performance. The die can have a slide surface (236, 244) and the coating fluid can exit the die from a passageway and slides along the slide surface to form a continuous coating bead between the manifold bar sharp edge, the upstream die lip, and the surface being coated. The die can include several passageways for coating multiple layers.
Abstract:
A web coating apparatus (20) includes a supply roll (26) of web (22) and a wind-up spindle (86) for receiving a discrete length of the web (22). Fluid is discharged from a coating die (92) in a direction toward the wind-up spindle (86) to coat the web (22) as the web (22) is wound about the wind-up spindle (86). A variable speed pump (108) directs fluid through the coating die (92) at flow rate that is proportional to the speed of advancement of the web (22). The apparatus (20) is particularly useful for coating discrete lengths of orthopedic splinting and casting tape that is packaged for single patient use.
Abstract:
A method of coating the surface of a substrate with an essentially solvent-free polymerizable fluid that includes passing the fluid through a die onto the surface of the substrate as the substrate moves relative to the die. The die includes a channel adapted to receive the fluid and an adjustable width slot in communication with said channel through which the fluid is passed formed between a substantially straight, sharp edge located on the downstream side of the substrate and a land located on the upstream side of the substrate.
Abstract:
A die coating method and apparatus includes a die (40) having an upstream bar (64) with an upstream lip (60) and a downstream bar (66) with a downstream lip (62). The upstream lip is formed as a land (68) and the downstream lip is formed as a sharp edge (70). Coating fluid exists the die (40) from the slot to form a continuous coating bead between the upstream die lip, the downstream die lip, and the surface being coated. A metering roller (332) removes excess coating fluid from the coated web. The apparatus can include a roller (330) on which the coating fluid is initially coated and which contacts a web. A doctor blade (338) or a metering roller removes excess coating fluid from the roller.
Abstract:
A die (10) for use in extrusion or coating processes includes an insert (28) that is releasably received in a chamber (20) of a die housing (12), and the insert (28) has one or more flow-controlling peripheral surfaces that extend in an arc about its central axis. In one embodiment of the invention, the insert (28) has ribs (44, 46) that separate the chamber into distinct parts for passage of two or more different fluid streams. In another embodiment, the insert is (28) rotatable about its central axis from a first position wherein fluid is discharged through an outlet passageway (24, 26, 27), and to a second position wherein the flow of fluid through the outlet passageway (24, 26, 27) is interrupted.
Abstract:
A die (20) useful in coating and extrusion processes has a housing (22) and an insert (34) removably received in a chamber (26) of the housing (22). The insert (34) controls to some extent the characteristics of fluid flow in the die (20) as well as the fluid flow exiting the die (20). The insert (34) is elongated and is round in sections perpendicular to its longitudinal axis, so that it may be inexpensively made by a lathe. As such, a number of insert of varying configurations may be retained on hand and used as needed to vary the flow characteristics when desired. End portions (38, 40) of the insert (34) are cylindrical and complementally engage an inner cylindrical wall section (24) of the housing (22).