Methods and apparatus for applying adhesives in patterns to an advancing substrate
Methods and apparatuses herein may provide for the application of viscous fluids, such as adhesives, in pre-determined patterns to an advancing substrate. The fluid application apparatus may include a slot die applicator and a substrate carrier. The substrate carrier may include one or more pattern elements and may be adapted to advance the substrate past the slot die applicator as the slot die applicator discharges adhesive onto the substrate. In operation, the substrate is disposed on the substrate carrier; the substrate carrier advances the substrate past the slot opening of the slot die applicator. In turn, the substrate is intermittently compressed between the slot die applicator and the pattern surface of the pattern element. As the substrate is intermittently compressed, adhesive discharged from the slot die applicator is applied onto the substrate in an area having a shape substantially the same as a shape defined by the pattern surface.
1. An apparatus for applying adhesive in a pattern to an advancing substrate, the substrate having an unconstrained caliper, Hs, and having a first surface disposed opposite of a second surface, the apparatus comprising:
a slot die applicator including a slot opening, a first lip, and a second lip, the slot opening located between the first lip and the second lip;
a substrate carrier adapted to advance the substrate past the slot die applicator, wherein when the first surface of the substrate is disposed on the substrate carrier, the substrate carrier is adapted to advance the second surface of the substrate past the slot opening of the slot die applicator, the substrate carrier comprising:
a base surface; and
a pattern element, wherein the pattern element includes a pattern surface, and wherein the pattern element protrudes outward from the base surface to define a distance, Hp, between the pattern surface and the base surface;
wherein as the substrate carrier advances the second surface of the substrate past the slot opening, the pattern element is advanced such that the pattern surface repeatedly advances past the first lip, the slot opening, and the second lip of the slot die applicator;
wherein the substrate carrier is positioned adjacent the slot die applicator to define a minimum distance, Hg, between the pattern surface of the pattern element and the first lip and the second lip that is less than the unconstrained caliper, Hs, of the substrate; and
wherein a sum of the distance, Hp, and distance, Hg, is greater than the unconstrained caliper, Hs, of the substrate.
2. The apparatus of claim 1 , wherein the substrate carrier comprises a roller.
3. The apparatus of claim 2 , the roller comprises a center axis of rotation, and wherein the pattern element protrudes radially outward from the center of axis of rotation from the base surface to define a distance, Hp, between the pattern surface and the base surface.
4. The apparatus of claim 1 , wherein the substrate carrier comprises an endless belt.
5. The apparatus of claim 1 , wherein the base surface comprises a continuous surface and wherein the substrate carrier further comprises a plurality of discrete pattern elements separated from each other by the continuous surface.
6. The apparatus of claim 5 , wherein each pattern element includes a pattern surface and wherein each pattern element protrudes outward from the continuous surface such that each pattern surface is separated from the continuous surface by the distance, Hp.
7. The apparatus of claim 5 , wherein the pattern surface of each pattern element defines shapes that are substantially identical to each other.
8. The apparatus of claim 1 , wherein the pattern surface comprises a continuous surface and the base surface comprises a plurality of discrete base surfaces separated from each other by the pattern element.
9. The apparatus of claim 8 , wherein the pattern element protrudes outward from each of the base surfaces such that each base surface is separated from the continuous surface by the distance, Hp.