| US 7,615,175 B2 | ||
| Method of improving coating uniformity | ||
| James M. Nelson, Lino Lakes, Minn. (US); Raghunath Padiyath, Woodbury, Minn. (US); Robert B. Secor, Stillwater, Minn. (US); Mark J. Stevenson, Forest Lake, Minn. (US); Michael J. Tichy, Staples, Minn. (US); and Robert A. Yapel, Oakdale, Minn. (US) | ||
| Assigned to 3M Innovative Properties Company, Saint Paul, Minn. (US) | ||
| Filed on Aug. 03, 2004, as Appl. No. 10/910,522. | ||
| Application 10/910522 is a division of application No. 10/027763, filed on Dec. 19, 2001, granted, now 6,813,820. | ||
| Prior Publication US 2005/0008782 A1, Jan. 13, 2005 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. B29C 47/14 (2006.01); B32B 27/00 (2006.01) | ||
| U.S. Cl. 264—212 [264/177.16; 425/224] | 5 Claims |
| 1. A method for extruding comprising:
disposing a shim having a varying thickness profile in a die, between a first die portion having a first surface and a second
die portion having a second surface, the shim being positioned across the entire width of the die but not extending into the
passage in the die through which extrudate passes beyond the first and second die portions, so as to form a slot between the
first surface and the second surface, the slot having a varying height dimension, which substantially corresponds to the shim
profile, said shim profile being selected from incrementally thicker approaching the middle of the width dimension, incrementally
thinner approaching the middle of the width dimension, and incrementally increasing in thickness along the width dimension;
and
extruding flowable material through the slot;
to obtain extrudate having substantially uniform thickness.
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