HK1079481B - Die and method for dispensing flowable material - Google Patents

Description

Mold and method for dispensing flowable material

Background

The present invention relates to die coating and molding. More particularly, the present invention relates to the construction of coated or embossed apertures.

The manufacturing and installation costs of coating and molding dies with continuous slots are expensive. The machining and adjustment costs of continuous slot fluid bearings are high. The benefit of maintaining a uniform feed slot is that the liquid exiting the slot maintains a continuous cross-section. To maintain a uniform feed slot across the web, the die must be large and require elaborate mounting arrangements to provide sufficient support structure around the slot. The "cross-web" direction generally refers to the width dimension of the substrate (typically a piece of paper or polymeric material) moving relative to the mold. The "cross web" direction is perpendicular to the direction of movement of the web relative to the mold. The "cross web" direction may be used to explain the direction of the die, the coating on the web, the extrudate, or the web itself.

A die with multiple orifices provides a less expensive option for a continuous slot die. The porous mold has a number of openings to allow fluid (e.g., liquid) to flow out of the mold dispensing chamber. To provide a continuous cross-section of fluid, the fluid moving through the die is converged by the external engagement surfaces or grooves after passing through the orifices. For example, in a fluid-carrying die, downstream of which fluid exits the die, a portion of the die is used to converge individual streams into a continuous stream that is coated onto a web (often referred to as a "smooth land"). Typically, the downstream end of the smooth mating surface is sharp to prevent ribbing and nicking of the coating. The length of the smooth engaging surface is typically measured in the downstream direction, from the aperture to the sharp edge. Other types of dies use "troughs" that collect and focus the fluid within the die prior to coating the fluid. Examples of porous are illustrated and described in U.S. patent 3,149,949; 4,774,109, respectively; 5,045,358, respectively; and 4,371,571, all of which are incorporated by reference in their entirety.

Because the adjacent streams from these aforementioned porous-type dies must converge to form a continuous cross-section of fluid prior to coating (or embossing) on a web or other substrate, previous dies of this type sometimes have a narrow range of coating (or extrusion) parameters (e.g., line speed, die set-up, desired thickness of the coated (or embossed) film, die position, etc.) in order to provide a continuous, smooth, and bubble-free coating (or embossing) layer. This is due to the need for such techniques that converge separate streams generated by adjacent wells. Particularly difficult is the point of convergence of the two streams. Air is often mixed into the fluid at this point and between the substrates causing defects in the final product.

Summary of The Invention

The present invention is a mold for dispensing a fluid substance. The mold consists of modules. The outer surface is located on the module. At least one slot extends perpendicularly into the outer surface. The slot has a longitudinal dimension, a first longitudinal side and a second longitudinal side 38 b. At least one support extends from the outer surface into the slot. The support extends continuously from the first longitudinal side to the second longitudinal side. At least a portion of the support member is positioned in a direction other than perpendicular to the longitudinal dimension. The support is positioned such that at least a portion extends through the void region from either of the first longitudinal side to the second longitudinal side in a direction perpendicular to the longitudinal dimension of the slot.

The invention relates to a mould for dispensing a flowable substance, comprising:

a module;

an outer surface on the module;

at least one slot extending perpendicularly into the outer surface and having a longitudinal dimension, a first longitudinal side and a second longitudinal side;

at least one support extending from the outer surface into the slot, the support extending continuously from the first longitudinal side to the second longitudinal side; and is

Wherein at least a portion of the support member is positioned in a direction that is not perpendicular to the longitudinal dimension such that at least a portion of either side extending continuously from the first longitudinal side to the second longitudinal side in a direction perpendicular to the longitudinal dimension of the slot passes through the at least one void region.

The invention relates to a mould for dispensing a flowable substance, comprising:

at least one module having a manifold and an outer surface;

at least one array of apertures defining a plurality of void regions extending to the outer surface so as to define a longitudinal dimension parallel to the outer surface and a width perpendicular to the longitudinal dimension and parallel to the outer surface;

and is

Wherein the apertures are positioned such that at least a portion of each aperture is located at each width along the longitudinal dimension of the array of apertures.

The invention also relates to a method of distributing flowable material through a die comprising:

moving the flowable substance through a slot in an outer surface of the die, the slot having a longitudinal dimension, a first longitudinal side, and a second longitudinal side;

maintaining the shape of the slot with at least one support structure extending from the outer surface to the slot and continuously extending between the first longitudinal edge and the second longitudinal edge; and

continuity of the flowable substance along the longitudinal dimension of the slot is maintained by placing the support structure at least partially in a direction other than perpendicular to the longitudinal dimension such that at least a portion of the support structure passes through the interstitial region in any plane between the first longitudinal side and the second longitudinal side in a direction perpendicular to the longitudinal dimension of the slot.

Drawings

In the disclosure of the present invention, several devices are illustrated. Throughout the drawings, like reference numerals are used to show features or components common to those devices.

FIG. 1 is a schematic view of one embodiment of the inventive die.

Figure 2 is a cross-sectional view of one embodiment of the inventive die.

FIG. 3 is a partial front view of one embodiment of the inventive die.

Fig. 3A is a partial front view of one embodiment of the inventive die.

Fig. 4 is a partial front view of a second embodiment of the inventive die.

Fig. 4A is a partial front view of a second embodiment of the inventive die.

Fig. 5 is a partial front view of a third embodiment of the inventive die.

Fig. 5A is a partial front view of a third embodiment of the inventive die.

Fig. 6 is a partial front view of a fourth embodiment of the inventive die.

Fig. 7 is a partial front view of a fifth embodiment of the inventive die.

Fig. 8 is a partial front view of a sixth embodiment of the inventive die.

Fig. 9A is a partial front view of a seventh embodiment of the inventive die.

Fig. 9B is a partial front view of an eighth embodiment of the inventive die.

While the above-identified drawing figures set forth several preferred embodiments of the invention, other embodiments are also encompassed by the above discussion. In all cases, this disclosure is set forth by way of illustration, and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of this invention.

Detailed Description

An exemplary mold of the present invention is illustrated in fig. 1 at 10. The illustrated die 10 is used in a free span coating process wherein a fluid 12 (i.e., a flowable substance) is removed onto a web 14 to form a coating 16. The longitudinal (or "cross-filament") direction of the die 10 is indicated by arrow 17. The longitudinal direction 17 is perpendicular to the direction of movement of the web 14 relative to the mould 10. The web 14 may be formed from a number of different materials including polymers or paper. The wire 14 moves through guide rolls 20A and 20B in the direction indicated by arrow 18. Roll 20A supports web 14 upstream of die 10 and roll 20B supports web 14 at a location downstream of die 10, creating a "free span" of web material on which fluid 12 is applied as coating 16. Although a free span fluid bearing coating process is illustrated, the die 10 of the present invention may be used with many other types of coating and molding processes, including fixed gap coating, curtain coating, and slide coating. In addition, the shape of the mold 10 may vary depending on the end user tooling and application.

A cross-sectional view of one embodiment of the inventive die 10 is illustrated in fig. 2. The mold 10 includes a mold block 22 that includes a mold block portion 24 and a cheek portion 26. A manifold 28 is formed inside the modular portion 24. Although the illustrated module 22 is formed from two sections, any number of sections may be used to form the module 22. For example, the module 22 may be divided into first and second sections 30A and 30B shown by dashed lines (e.g., secured by bolts or clamps). When the panel portions 26 of the mold 10 are formed separately from the module portions 24, the use of different panel portions 26 on the same module portion 24 is achieved. Alternatively, module section 24 and faceplate section 26 may be formed from a single integral piece of metal to form module 22. The outer face 32 is located on the face portion 26 of the module 22. Slots 34 extend into exterior surface 32 of faceplate portion 26 in communication with manifold 28.

The fluid substance is generally introduced into manifold 28 by a pump (not shown) known in the art, such as a die press or a positive displacement pump (e.g., a gear pump or a metering pump (etc.)) the pressure created in manifold 28 by the pump forces fluid 12 out of slot 34 as fluid 12 exits slot 34 wets outer surface 32 of panel portion 26 and forms first and second static lines 36A and 36B as is known in the art and may be defined as fluid 12, outer surface 32 and a coupling line that surrounds die 10 (typically air) or possibly another layer of fluid (e.g., in a multi-operation coating die.) static line 36A is formed on die 10 on each side of slot 34 as defined by width dimension 37. width dimension 37 of slot 34 is defined between edge 41A of upstream-most orifice 40B and edge 41B of downstream-most orifice 40A. fluid substance 12 flows in a direction generally parallel to outer surface 32 on panel portion 26. The orientation is generally indicated by reference numeral 39. The die 10 may be placed against a web 14 (shown in dotted lines) to cause the fluid 12 to form a coating (or film) 16 on the web 14. Alternatively, the mold 10 may be used to mold the fluid 12 as a separate film, such as in a cast molding process as is known in the art.

Additionally, multiple layers of fluid may be molded or coated by the mold 10.

Fig. 3 illustrates a first embodiment of the outer surface 32 of the inventive die 10. The slot 34 is shown extending in the longitudinal dimension 17. The slot 34 has a first longitudinal side 38A and a second longitudinal side 38B shown by dotted lines. A plurality of apertures (or void areas) 40 extend into exterior surface 32 of faceplate portion 26. The plurality of supports 42 are positioned such that a single support 42A is positioned between each adjacent aperture 40A and 40B. It is noted that when referring to holes and supports, only the reference numbers (i.e., "hole 40" and "support 42") will be used, however, when referring to a particular hole or support, one letter (i.e., "hole 40A" and "support 42A") will be appended.

The support member 42 extends continuously from the first longitudinal side 38A to the second longitudinal side 38B of the slot 34 in a manner such that any plane (represented by arrow 44) located between the first and second longitudinal sides 38A, 38B passes through the at least one aperture (or void) 40 in a direction perpendicular to the longitudinal (or cross-filament) dimension 17.

In the illustrated embodiment, the support 42 extends from the first and second longitudinal sides 38A and 38B at an angle of approximately 60 degrees relative to the first and second longitudinal sides 38A and 38B. In one embodiment, the thickness (in the longitudinal direction 17) of each support is less than or equal to about 5 mils (about 130 microns) (indicated by the numeral 45) and the slot width 37 is less than or equal to about 40 mils (about 1020 microns), although the dimensions and widths may vary depending on the end application. The support members 42 placed in this manner form apertures 40 which are generally in the shape of equilateral triangles. While 9 holes 40 are illustrated, the number may vary depending on the end application (e.g., the length of slot 34). The distance that supports 42 extend from outer surface 32 into slots 34 may vary depending on the end application.

The support at the slot 34 can be formed in different ways contemplated in the present application. For example, the holes 40 may be machined (e.g., drilled) into the outer surface 32, or form part of a shim or insert (optionally shown by dotted lines 46 in fig. 3A). Spacers 46 may be used to define slots 34 in module 22 and include the support structures 42 and apertures 40 as described. When a shim 46 (the general application of which is known) is used to include the supports 42 and apertures 40 in the slot 34, it allows the configuration of the slot 34 to be changed by removing the shim 46 from the die 10 and replacing it with another shim (not shown) having a different configuration of supports 42 and apertures 40 such as that described below with respect to fig. 4, 5, 6, 7.

The support 42 runs continuously from the first longitudinal side 38A to the second longitudinal side 38B such that the first and second longitudinal sides 38A and 38B are prevented from "bending" in a convex or concave manner thereby deforming the slot 34. "bowing" occurs due to the pressure required to push a fluid (e.g., liquid) 12 through the die 10, and can vary depending on the physical properties (e.g., viscosity) of the fluid 12. Some typical coating and molding processes may produce pressures on the longitudinal sides 38A and 38B of slot 34 from about 5psi (about 34kPa) to about 100psi (about 690 kPa). This pressure level is resisted by the support member 42.

Preventing "bowing" provides a highly uniform flow rate of fluid 12 out of slot 34 (i.e., through holes 40) across the width of the die. In the direction of flow of the fluid (e.g., liquid) 12, the overlapping of the apertures 40 (illustrated by plane 44) causes the flow of the fluid 12 to "overlap" as the fluid exits the apertures 40, thereby maintaining the cross-sectional continuity of the fluid film in the cross-web direction. In other words, the gaps and air bubbles are minimized so that a continuous layer (or film) of fluid is coated (or extruded) onto the web 14 in a direction across the web (i.e., in the longitudinal dimension 17 of the die 10). This is due to the release of fluid 12 from voids or holes 40 along the respective flat surfaces 44 of the longitudinal dimension 17 of the mold 10. Thus, the advantages of the structure (i.e., support 42) in the slot 34 (e.g., preventing "bowing") may be utilized while still releasing a continuous layer of coating fluid 12. The "overlap" is illustrated by the dotted lines between the apertures 40, representing the fluid 12 on the web 14. The overlap minimizes the need for structures, such as smooth lands or grooves (i.e., continuous grooves extending into the outer surface 32), to provide separate flows of fluid further downstream from the connection slot 34. This allows a smaller die of a desired strength requiring minimal physical space to be used to withstand the pressure required to push the fluid 12 through the die 10.

The first static line 36A is nearest the first longitudinal side 38A of the slot 34. The second static line 36B is nearest the second longitudinal side 38B. It is noted that the position of static lines 36A and 36B may vary with respect to position on outer surface 32, depending on the type of coating or embossing being performed, as well as the coating and embossing apparatus, etc. For example, the first static line 36A may be placed on a portion of the support structure 42. It should also be noted that the first static line 36A is located on the outer surface 32 closer to the first longitudinal side 38A than the second longitudinal side 38B. In addition, the second line 36B is located on the outer surface 32 closer to the second longitudinal side 38B than the first longitudinal side 38A. The cross-sectional shape of each aperture 40 (i.e., a plane generally parallel to outer surface 32) preferably defined by support structure 42 extends substantially the entire slot width 37. In other words, the width of each aperture 40 (defined generally perpendicular to the longitudinal direction 17) at the outer surface 32 is substantially the same as the slot width 37. This preferred configuration is exemplified, inter alia, by the embodiments illustrated in fig. 3-4A and 6-8. Providing apertures 40 of substantially the same width as slots 34 enhances the performance characteristics of die 10 of the present invention so that higher coating speeds can be employed and the thickness of coating 16 can be controlled.

A second embodiment of the inventive die 10 is illustrated in fig. 4. In this embodiment, the hole 50, which is elliptical in cross-section, is formed by a diagonal support 52. The support 52 is positioned such that a plane 44 extending between the first and second longitudinal sides of the slot 34 in a direction perpendicular to the longitudinal dimension 17 or the slot 34 passes through the at least one aperture (or void) 50. On the other hand, as shown in FIG. 4A, as fluid 12 flows out of apertures 50, an overlap of fluid 14 is provided, creating a continuous cross-section in the direction across the web. As noted above, the size and number of the aperture 50 supports 52 (described in all embodiments herein) may vary depending on the end application.

Fig. 5 illustrates a third embodiment of the inventive die 10 in which oval-shaped holes 60 are located in the outer surface 32 of the rim portion 26. The extension of support members 62 between apertures 60 provides a structure that prevents slot 34 from "bending". Although not having a significantly linear shape, the individual supports 62A, 62B, 62C and 62D are shaped such that the plane 44 is perpendicular to the longitudinal sides 38A and 38B to pass through the at least one hole (or void) 60.

As shown in fig. 5A, the fluid 12 moves through the apertures 60 to "overlap" as the fluid 12 moves downstream (arrow 64) from the aperture 60 such that air gaps and discontinuities in the fluid 12, as a coating or molding on the web 14, in the longitudinal dimension 17 are minimized (and preferably eliminated).

Fig. 6-8 illustrate other embodiments of the inventive die 10. Specifically, fig. 6 illustrates a support 72 that forms a trapezoidal aperture (or void) 70 in the outer surface 32. Fig. 7 illustrates a support 82 that forms a parallelogram-shaped aperture (or void) 80 in the outer surface 32. Fig. 8 illustrates a support 92 that forms a pentagonal aperture (or void) 90 in the outer surface 32. In each of the embodiments illustrated in fig. 6-8, a plane 44 may be defined that extends between the first and second longitudinal sides 38A and 38B of the slot 34 in a direction perpendicular to the longitudinal dimension 17 of the slot 34. Each plane 44 along the longitudinal dimension 17 of the slot 34 extends through at least one hole (or void) (indicated by the numerals 70, 80, 90 in fig. 6, 7 and 8, respectively). A number of support structures 72, 82 and apertures 70 and 80 may be used in the mold of the present invention without departing from the spirit and scope of the present invention. This is reflected by small straightness deviations from the longitudinal direction 17 and other stability of the static line 36B across the outer surface 32. It is noted that in one embodiment illustrated in fig. 9B, a multi-slit 34 extending partially along the longitudinal dimension 17 of the exterior surface 32 may be used. The multi-slot 34 includes apertures (indicated by reference numerals) 40 and 50 separated by support structures 42 and 52. In addition, any combination of arrow numbers (e.g., multiple film layers) and any number and any shape of apertures may be used in combination in the mold of the present invention. For example, three slots may be "stacked" as illustrated in fig. 9A to extend along the longitudinal dimension 17 of the outer surface 32, resulting in three film layers. Each slot 34 may have a different aperture shape (as shown), including a continuous slot without a support structure. Alternatively, the orifice shape may vary within each slot.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims (18)

1. A mold for dispensing a flowable material comprising:

a module;

an outer surface on the module;

at least one slot extending perpendicularly into the outer surface and having a longitudinal dimension, a first longitudinal side and a second longitudinal side;

at least one support extending from the outer surface into the slot, the support extending continuously from the first longitudinal side to the second longitudinal side; and is

Wherein at least a portion of the support member is positioned in a direction that is not perpendicular to the longitudinal dimension such that at least a portion of either side extending continuously from the first longitudinal side to the second longitudinal side in a direction perpendicular to the longitudinal dimension of the slot passes through the at least one void region.

2. The mold defined in claim 1, wherein the outer surface is positioned such that, when the flowable substance is dispensed from the mold, a first static line of contact is formed on the outer surface that is closer to the first longitudinal side than the second longitudinal side, and a second static line of contact is formed on the outer surface that is closer to the second longitudinal side than the first longitudinal side.

3. The mold of claim 1, further comprising:

the plurality of struts extend from the first longitudinal side such that a plurality of void areas defined by the plurality of apertures are defined in a plane of the outer surface between each two adjacent struts.

4. The mold of claim 1, and further comprising:

a plurality of slots designed to allow the die to stamp the multilayer fluid film layer.

5. The mold of claim 1, and further comprising:

a plurality of slots extending into the outer surface along a single longitudinal plane.

6. A mold for dispensing a flowable substance comprising:

at least one module having a manifold and an outer surface;

at least one array of apertures defining a plurality of void regions extending to the outer surface so as to define a longitudinal dimension parallel to the outer surface and a width perpendicular to the longitudinal dimension and parallel to the outer surface; and is

Wherein the apertures are positioned such that at least a portion of each aperture is located at each width along the longitudinal dimension of the array of apertures.

7. The mold of claim 3 or 6, wherein the module further comprises:

a manifold located in the module, wherein the bore communicates with the manifold.

8. The mold of claim 1 or 6, wherein the module further comprises:

a movable panel portion, wherein the outer surface is located on the panel portion.

9. The mold of claim 1 or 6, wherein the module further comprises:

a plurality of modular segments movably secured to one another.

10. The mold of claim 3 or 6, wherein the module further comprises:

a shim in which the aperture is formed.

11. A mould according to claim 3 or 6 wherein each void is substantially triangular in shape.

12. A mould according to claim 3 or 6, wherein each void is substantially polygonal in shape.

13. A mould according to claim 3 or 6, wherein the shape of each void may vary between voids.

14. The mold of claim 1 or 6, wherein the mold is used in a coating type process.

15. The mold of claim 1 or 6, wherein the mold is used in a free span type coating process.

16. A method of dispensing flowable material through a die comprising:

moving the flowable substance through a slot in an outer surface of the die, the slot having a longitudinal dimension, a first longitudinal side, and a second longitudinal side;

maintaining the shape of the slot with at least one support structure extending from the outer surface to the slot and continuously extending between the first longitudinal edge and the second longitudinal edge; and

continuity of the flowable substance along the longitudinal dimension of the slot is maintained by placing the support structure at least partially in a direction other than perpendicular to the longitudinal dimension such that at least a portion of the support structure passes through the interstitial region in any plane between the first longitudinal side and the second longitudinal side in a direction perpendicular to the longitudinal dimension of the slot.

17. The method of claim 16, and further comprising:

moving the fluid along the outer surface after the step of moving the flowable substance through the slot.

18. The method of claim 16, and further comprising:

forming a static contact line on one of the outer surface and the support structure that is closer to the first longitudinal side than the second longitudinal side; and

a static contact line is formed on the outer surface closer to the second longitudinal side than the first longitudinal side.