WO1999054057A1 - Method and apparatus for applying a controlled pattern of fibrous material to a moving substrate - Google Patents

Abstract

A system (2) for dispensing liquid material onto a moving substrate (30) includes a liquid dispenser (16) fluidly connected to a source of liquid material (4) and a source of pressurized air (6). The liquid dispenser (16) includes a plurality of liquid material outlets (76) spaced along a common axis at one end of the dispenser (16) for dispensing a plurality of strands (27a) of liquid material toward the substrate (30). The liquid dispenser (16) further includes a pair of air outlets (84) associated with each of the liquid material outlets (76) for emitting pressurized air (100) that is operable to oscillate the dispense strands in directions predominantly parallel with the common axis of the liquid material outlets (76) during flight toward the substrate (30) to form an overlapping pattern (104) of liquid material on the moving substrate (30). Methods for dispensing liquid material onto a moving substrate are also disclosed.

Description

METHOD AND APPARATUS FOR APPLYING

A CONTROLLED PATTERN OF FIBROUS MATERIAL

TO A MOVING SUBSTRATE

Cross-Reference

The present application claims the filing benefit of co-

pending provisional application Serial No. 60/082,069, filed on April

17, 1998, the disclosure of which is expressly incorporated herein by

reference in its entirety.

Field of the Invention

The present invention relates generally to material

dispensing systems for applying material onto a substrate and, more

particularly, to a material dispensing system having a modular die

assembly for applying in a controlled manner patterns of fibrous

material onto a moving substrate.

Background of the Invention

Various dispensing systems have been used in the past

for applying patterns of viscous material onto a moving substrate. - 2 -

In the production of disposable diapers, incontinence pads and

similar articles, for example, hot melt adhesive dispensing systems

have been developed for applying a laminating or bonding layer of

hot melt thermoplastic adhesive between a non-woven fibrous layer

and a thin polyethylene backsheet. Typically, the hot melt adhesive

dispensing system is mounted above a moving polyethylene

backsheet layer and applies a uniform pattern of hot melt adhesive

material across the upper surface width of the backsheet substrate.

Downstream of the dispensing system, a non-woven layer is

laminated to the polyethylene layer through a pressure nip and then

further processed into a final usable product.

In one known hot melt adhesive dispensing system,

continuous beads or strands of adhesive are emitted from a multiple

adhesive outlet die with multiple air jets oriented around the

circumference of each material outlet. The multiple air jets drive air

tangentially relative to the orientation of the adhesive strand as it

emits from the die orifice, thereby attenuating each adhesive strand

and causing the strands to swirl before being deposited on the

upper surface of the moving substrate.

More recently, manufacturers of diaper products and

others have been interested in small fiber technology for the - 3 - bonding layer of hot melt adhesive in non-woven and polyethylene

sheet laminates. To this end, hot melt adhesive dispensing systems

have incorporated slot nozzle dies with a pair of angled air channels

formed on either side of the elongated extrusion slot of the die. As

the hot melt adhesive emits from the extrusion slot as a continuous

sheet or curtain, pressurized air is emitted as a pair of curtains from

the air channels to impinge upon, attenuate and fiberize the adhesive

curtain to form a uniform fibrous web of adhesive on the substrate.

Recently, fibrous web adhesive dispensers have incorporated

intermittent control of adhesive and air flows to form discrete

patterns of fibrous adhesive layers with well defined cut-on and cut¬

off edges and well defined side edges.

Meltblown technology has also been adapted for use in

this area to produce a hot melt adhesive bonding layer having fibers

of relatively small diameter. Meltblow dies typically include a series

of closely spaced adhesive nozzles that are aligned on a common

axis across the die head. A pair of angled air channels are formed

on either side of the adhesive nozzles to extend parallel to the

common nozzle axis. As hot melt adhesive emits from the series of

aligned nozzles, pressurized air is emitted from the air channels as a - 4 - pair of curtains that impinge upon, draw down and attenuate the

fibers before they are applied to the moving substrate.

While meltblown technology has been used to produce

fibrous adhesive layers on moving substrates, it has several

drawbacks. As those skilled in the art will appreciate, meltblown

technology typically uses a high volume of high velocity air to draw

down and attenuate the emitted adhesive strands. The high velocity

air causes the fibers to oscillate in a plane that is generally aligned

with the movement of the substrate, i.e., in the machine direction.

To adequately blend adjacent patterns of adhesive to form a uniform

layer on the substrate, meltblow dispensers require the nozzles to be

closely spaced. Moreover, the volume and velocity of the air must

be high enough to sufficiently agitate and blend adjacent fibers.

However, the high volume of air used in meltblown

dispensers adds to the overall operational cost as well as reduces

the ability to control the pattern of emitted fibers. One byproduct of

the high velocity air is "fly" in which the fibers get blown away from

the desired deposition pattern. The "fly" can be deposited either

outside the desired edges of the pattern, or even build up on the

dispensing equipment which can cause operational problems that

require significant maintenance. Another byproduct of the high - 5 - velocity air and closely spaced nozzles is "shot" in which adjacent

adhesive fibers become entangled and form globules of adhesive on

the backsheet substrate. "Shot" is undesirable as it can cause heat

distortion of the delicate polyethylene backsheet.

It will further be appreciated by those skilled in the art

that the construction of the meltblow dies, with the continuous

sheets of air formed on either side and parallel to the aligned

nozzles, reduces the ability of manufacturers to modularize the

meltblow dies in side-by-side fashion across the width of a moving

substrate. The curtains of air are interrupted between adjacent melt

blow dies which generally results in a less consistent fiber pattern on

the substrate.

Additionally, the many closely spaced nozzles required

in meltblow dies not only adds to manufacturing costs, but also

forces lower material flow rates through each nozzle. Lower material

flow rates per nozzle generally results in a greater variation of the

fibers emitted from the nozzles. Moreover, the nozzles are typically

more likely to clog at the lower material flow rates.

Thus, there is a need for a material dispensing system

that improves control of dispensed material to form patterns on a

moving substrate without "fly" or "shot". There is also a need for a - 6 - material dispensing system that reduces costs associated with

operation and maintenance. There is yet another need for a material

dispensing system that improves the ability to modularize the

dispensing system to provide a wider range of uniform material

pattern widths across a moving substrate.

Summary of the Invention

The present invention overcomes the foregoing and

other shortcomings and drawbacks of the material dispensing

systems and methods heretofore known. While the invention will be

described in connection with certain embodiments, it will be

understood that the invention is not limited to these embodiments.

On the contrary, the invention includes all alternatives, modifications

and equivalents as may be included within the spirit and scope of the

present invention.

The present invention is directed to a material

dispensing system and method for use in applying in a controlled

manner a fibrous material in a desired pattern on a moving

substrate. The material dispensing system has a source of fluid

material to be applied and a source of pressurized air that are

connected to a material dispensing head. The material dispensing

head has a fluid manifold connected to the source of material, an air - 7 - manifold connected to the source of pressurized air, and a

dispensing module having an upper dispensing body and a lower

modular die assembly mounted to one end of the dispensing body.

The dispensing body is connected to the fluid manifold for delivering

fluid in a controlled manner to the die assembly. The modular die

assembly includes a series of aligned material outlets that emit the

fluid in a series of spaced strands toward a substrate. The

dispensing body is connected to the air manifold for delivering

pressurized air in a controlled manner to the die assembly. The

pressurized air is used to draw down and attenuate the strands to

form fibers that oscillate in a generally transverse plane relative to

the direction of travel of the moving substrate. The oscillation of the

fibers provides a uniform pattern of fibrous material on the moving

substrate. The pressurized air between the material outlets also

separates the strands during the critical draw down phase to prevent

entanglement of adjacent strands. The orientation of the air and

material outlets in accordance with the principles of the present

invention improves control of the dispensed material to form a

desired pattern on the moving substrate.

In accordance with one aspect of the present invention,

the modular die assembly has a die block mounted to a lower end of - 8 - the dispensing body. The die block has a seat for mounting a

pattern die and sealing plate to a lower end of the die block. Material

passages are formed in the die block for delivering viscous material

from the dispensing body to the pattern die. Air passages are also

formed in the die block for delivering pressurized air from the air

manifold to the pattern die. The sealing block is mounted to provide

a seal between the various components of the modular die

assembly.

The pattern die has a series of spaced openings that are

preferably aligned on a common axis along a lower surface of the

pattern die. A nozzle is preferably fitted into each spaced opening.

The pattern die has material passages that communicate with the

material passages in the die block for delivering the viscous material

to the nozzles. The nozzles receive the viscous material from the

material passages in the pattern die, and emit the material as spaced

strands. The pattern die further includes a series of spaced air

outlets that are also preferably aligned on a common axis along the

lower surface of the pattern die. The pattern die air passages

communicate with the air passages in the die block and provide

pressurized air to the air outlets. Preferably, a pair of air outlets are - 9 - positioned adjacent each material outlet and each air outlet is formed

on an opposite side of the respective material outlet.

In operation, the pattern die emits the viscous material

preferably from the nozzles as spaced strands toward a surface of

the moving substrate. The pattern die also emits air generally

between the strands to draw down and attenuate the strands into

small fibers that are deposited uniformly onto the moving substrate.

The orientation of the material outlets and air outlets in

accordance with the principles of the present invention preferably

causes the fibers to oscillate in a generally cross-machine direction

that improves blending of adjacent fibers. The air between the

material outlets also prevent entanglement of adjacent strands

during the critical draw down phase to reduce "shot" formation on

the moving substrate. Additionally, the orientation of the material

outlets and air outlets requires less volume and velocity of air to

create a uniform pattern of fibrous on the web. With less volume

and velocity of air, the material dispensing system reduces

undesirable "fly" formation and lowers operational and maintenance

costs of the material dispensing system. Moreover, the orientation

and operation of the material outlets and air outlets improves the - 10 - ability to modularize the dispensing system to provide a wider range

of uniform pattern widths across a moving substrate.

Brief Description of the Drawing

The accompanying drawings, which are incorporated in

and constitute a part of this specification, illustrate embodiments of

the invention and, together with a general description of the

invention given above, and the detailed description of the

embodiments given below, serve to explain the principles of the

invention.

Fig. 1A is a functional block diagram of a material

dispensing system in accordance with the principles of the present

invention.

Fig. 1 B is an exploded view of a modular die assembly

in accordance with the principles of the present invention showing

the die assembly mounted on a lower end of a material dispensing

body;

Fig. 2 is a cross-sectional view, taken along line 2-2 of

Fig. 1 B, showing one embodiment of the die assembly, and

mounting of the various die assembly components;

Fig. 3 is a cross-sectional view, taken along line 3-3 of

Fig. 2, illustrating a pattern die in accordance with one embodiment - 11 - of the present invention, and the material dispensing pattern created

by the die assembly across the width of a moving substrate;

Fig. 3A is a side view, taken along line 3A-3A of Fig. 3,

illustrating the material dispensing beam created by the die

assembly;

Fig. 3B is a diagrammatic top plan view, taken along line

3B-3B of Fig. 3, illustrating a material dispensing footprint created by

the die assembly;

Fig. 4 is a bottom view of the pattern die illustrated in

Fig. 3, taken along line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 3, illustrating a pattern die

in accordance with a second embodiment of the present invention;

Fig. 6 is a bottom view of the pattern die illustrated in

Fig. 5, taken along line 6-6 of Fig. 5;

Fig. 7 is a view similar to Fig. 3, illustrating a pattern die

in accordance with a third embodiment of the present invention;

Fig. 7A is a perspective view of a nozzle insert shown in

Fig. 7;

Fig. 8 is a bottom view of the pattern die illustrated in

Fig. 7, taken along line 8-8 of Fig. 7; - 12 - Fig. 9 is a view similar to Fig. 3, illustrating a pattern die

in accordance with a fourth embodiment of the present invention;

Fig. 10 is a bottom view of the pattern die illustrated in

Fig. 9, taken along line 10-10 of Fig. 9;

Fig. 1 1 is a view similar to Fig. 3, illustrating a pattern

die in accordance with a fifth embodiment of the present invention;

Fig. 1 1A is a perspective view of a nozzle insert shown

in Fig. 1 1 ;

Fig. 12 is a bottom view of the pattern die illustrated in

Fig. 1 1 , taken along line 12-12 in Fig. 1 1 ;

Fig. 13 is diagrammatic cross-sectional view of a

modular die assembly in accordance with an alternative embodiment

of the present invention;

Fig. 14 is a bottom view of a pattern die illustrated in

Fig. 13, taken along line 14-14 of Fig. 13;

Fig. 15 is an exploded view of a modular die assembly

in accordance with a third embodiment of the present invention;

Fig. 15A is an enlarged view, in elevation, of the

encircled area 15A in Fig. 15; and - 13 - Fig. 16 is a cross-sectional view of the modular die

assembly of Fig. 15 fully assembled, showing mounting of the

various die components.

Detailed Description of the Preferred Embodiments

Referring now to the figures, and to Fig. 1 A in

particular, an overall material dispensing system 2 in accordance

with the principles of the present invention is shown for dispensing a

pattern of material on a moving substrate. For purposes of

simplifying description of the present invention, the preferred

embodiment will hereinafter be described in relation to the

dispensing of hot melt thermoplastic adhesives, but those skilled in

the art will readily appreciate application of the present invention to

dispensing of other materials as well such as polymer and rubber

based sealants and adhesive based materials. Material dispensing

system 2 includes a source of material 4 and a source of pressurized

air 6 that are each connected to a material dispensing head 8

through suitable delivery hoses or conduits 10a and 10b,

respectively. Material source 4 may be, for example, an unloader

and melter having a suitable hopper, melting grid and pump for

delivering heated, viscous hot melt adhesive to the material

dispensing head 8. Air source 6 may be a compressor or other - 14 - suitable device for delivering pressurized air to the material

dispensing head 8 as will be appreciated by those skilled in the art.

Material dispensing head 8 preferably has a fluid

manifold 12 connected to the source of material 4 through hose 10a,

and an air manifold 14 connected to the source of pressurized air 6

through hose 10b. A dispensing module 16 is provided having an

upper dispenser body 18 mounted to the fluid manifold 12, and a

lower modular die assembly 20 mounted to a lower end of the

dispenser body 18. Die assembly 20 preferably includes a die block

22, a pattern die 24 and a sealing plate 26 that cooperate for

purposes to be described in detail below. In operation, the

dispenser body 18 receives viscous material from the fluid manifold

12 and delivers it in a controlled manner to the die assembly 20. Die

assembly 20 also receives pressurized air from the air manifold 14

and is operable to apply the viscous material as a fibrous pattern on

a moving substrate as described in detail below. Of course, the

source of pressurized air 6 could also be connected to dispensing

body 18 and then to the die assembly 20.

With reference to Fig. 1 B, the die assembly 20 is shown

in greater detail mounted to a lower end of dispenser body 18 in

accordance with the principles of the present invention. As will be - 15 - described in more detail below, die assembly 20 is particularly

adapted to emit plural strands 27a of hot mejt adhesive that are

drawn down and attenuated into fibers 27b for deposition on a

surface 28 of a moving substrate 30 (Fig. 3). As used herein, the

term "fibrous material" refers to viscous material that is emitted from

one or more material outlets in strand form, and which strands are

drawn down or attenuated by pressurized air to form smaller

diameter fibers. The fibers 27b can be of almost any diameter, but

for hot melt adhesive applications, the diameters are typically in the

range of 200 microns or less. It will be appreciated that other

diameters are possible depending on the specific dispensing

application.

As best understood with reference to Fig. 2, dispenser

body 18 is adapted to provide a controlled continuous or intermittent

flow of hot melt adhesive to the die assembly 20. Dispenser body 18

is mounted to the heated fluid manifold 12, and includes an adhesive

cavity (not shown) for receiving viscous hot melt adhesive from the

manifold 12. The air manifold 14 is mounted to a lower end of the

fluid manifold 12 through fasteners (not shown) that extend through

a spacer 31 mounted between the fluid and air manifolds 12 and 14,

respectively. The air manifold 14 is formed with an air inlet line 32 - 16 - fluidly connected to an air connector bore 34 formed in the die block

22. Pressurized air source 6 is fluidly connected to the air inlet line

32 for providing controlled, continuous or intermittent air supply to

the air connector bore 34 formed in the die block 22. An O-ring 36

forms a fluid-tight seal between the die block 22 and the air manifold

14 at the junction of the air inlet line 32 and air connector bore 34. It

will be appreciated that while fluid manifold 12 and air manifold 14

are shown as separate components, they could be combined as a

single unit. It will be further appreciated that the adhesive and air

could be continuous or intermittent depending on the specific

dispensing application.

As shown with further reference to Fig. 2, the modular

die assembly 20 is mounted to the lower end of the dispenser body

18 via four fasteners 38 that extend through unthreaded bores (not

shown) formed in the die assembly 20. At their threaded ends, the

set of fasteners 38 are connected to threaded bores (not shown)

formed in the lower end of the dispenser body 18. The dispenser

body 18 is heated by conduction via its contact with fluid manifold

12, and the die assembly 20 is heated by conduction via its contact

with the dispenser body 18. Dispenser body 18 is preferably a

Model H200 hot melt adhesive dispenser commercially available - 17 - from Nordson Corporation of Westlake, Ohio. The details of the

structure and operation of Nordson's H200 hot melt adhesive

dispenser may be found in U.S. Patent Nos. 4,801 ,051 and 5,277,344,

each of which is incorporated herein by reference in its entirety. The

structure of the adhesive manifold 12, air manifold 14 dispenser

body 18 can assume any form without departing from the principles

and scope of the present invention, and are discussed briefly herein

for purposes of background only. It will be appreciated by those of

ordinary skill in the art that while die assembly 20 is shown mounted

to a lower end of dispenser body 18, other mounting locations of die

assembly 20 on dispenser body 18 are possible without departing

from the spirit and scope of the present invention.

As shown with reference to Figs. 1A-4, the die assembly

20 includes various die components that are collectively mounted to

the lower end of the dispenser body 18 via the set of fasteners 38.

Preferably, the die assembly 20 includes the die block 22 having a

mounting end 42 (Fig. 2) for fluidly connecting the die assembly 20

to the dispenser body 18. The mounting end 42 extends into the

adhesive cavity (not shown) of the dispenser body 14, and is sealed

with walls 43 of the adhesive cavity via an O-ring 44. Die block 22

includes a vertical wall or surface 46 and a horizontal wall or surface - 18 - 48 that define a seat 49 for mounting the pattern die 24 and sealing

plate 26 to a lower end of the die block 22, as best understood with

reference to Figs. 1 A-2. Pattern die 24 and sealing plate 26 include

respective apertures 54a, 54b, and slots 56a, 56b extending through

the respective die components for receiving a pair of fasteners 58

that mount the components to the vertical wall 46 of die block 22. It

will be appreciated by those of ordinary skill in the art that slots 56a,

56b formed through the pattern die and sealing plates 24 and 26 are

provided to accommodate for thermal expansion of the various die

components caused by heat generated during the hot melt adhesive

dispensing process.

With further reference to Figs. 1 B and 2, pattern die 24

preferably includes a series of elongated, vertically and horizontally

oriented air distribution channels 60a and 60b formed on one face 61

of the pattern die, and an elongated, horizontally oriented adhesive

distribution channel 62 formed on the other face 63 of the pattern die

for purposes to be described in detail below. Pattern die 24

preferably includes six (6) bores 64 formed through a lower surface

66 of the pattern die that extend upwardly and fluidly connect with

six (6) transverse passages 68 (one shown in Fig. 2) extending

horizontally inwardly from the elongated adhesive distribution - 19 - channel 62. Bores 64 preferably have a circular cross-section and

are preferably aligned along an axis that is generally parallel to the

longitudinal axis of the pattern die 24. The bores 64 are also

preferably spaced equidistantly along the lower surface 66 of the

pattern die 24. Bores 64 are sized to receive respective tubular

nozzle inserts 70 that are inserted and frictionally engaged within the

bores 64. Each nozzle insert 70 has an elongated adhesive passage

72 that extends generally along the longitudinal axis of the nozzle

insert. Each adhesive passage 72 preferably has a uniform cross-

sectional shape between an upper surface 74 of the nozzle insert 70

and a conically-shaped material outlet 76 formed at a lower end of

each nozzle insert 70 that extends below the lower surface 66. It will

be appreciated by those of ordinary skill in the art that adhesive

passage 72 could be tapered without departing from the spirit and

scope of the present invention. While adhesive passages 72 and

material outlets 76 are shown having circular cross-sectional shapes,

it is contemplated that square, rectangular or other cross-sectional

shapes are possible for adhesive passages 72 and material outlets 76

without departing from the spirit and scope of the present invention.

While six (6) bores 64 and six (6) nozzle inserts 70 are shown, it will

be appreciated that fewer or more bores and nozzle inserts are - 20 - possible depending on a specific material dispensing application.

Moreover, it will be appreciated that while nozzle inserts 70 are

preferred, they may be replaced with a series of adhesive passages

drilled or otherwise formed in the lower surface 66 of pattern die 24.

Pattern die 24 further preferably includes a pair of

transverse passages 78 (one shown in Fig. 2) extending through the

pattern die that fluidly connect with the respective pair of vertically

oriented air distribution channels 60a. The pair of vertically oriented

air distribution channels 60a are fluidly connected to the horizontally

oriented air distribution channel 60b formed on the one face 61 of

the pattern die 24 (Figs. 1 B-2).

In accordance with one embodiment of the present

invention as shown with reference to Figs. 2-4, the pattern die 24

includes a series of twelve (12) air passages 80 formed through the

lower surface 66 of the pattern die that extend upwardly and fluidly

connect with twelve (12) transverse passages 82 (one shown in Fig.

2) extending horizontally inwardly from the horizontally oriented air

distribution channel 60b. Air passages 80 form air outlets 84 on the

lower surface 66 of pattern die 24 that are preferably grouped in

pairs in association with each material outlet 76. In this preferred

arrangement, it will be appreciated by those of ordinary skill in the - 21 - art that for six (6) material outlets 76, twelve (12) air passages 80 and

twelve (12) transverse passages 82 are required. If the number of

material outlets 76 increases or decreases, the number of air

passages 80 and transverse passages 82 increases or decreases as

well.

Preferably, the air passages 80 and air outlets 84

formed in association with the material outlets 76 are aligned

generally along the axis of the material outlets 76, with each pair of

air outlets 84 being positioned on opposite sides of a respective

material outlet 76 for purposes to be described in more detail below.

While air passages 80 and air outlets 84 are shown having circular

cross-sectional shapes, it is also contemplated that square,

rectangular or other cross-sectional shapes are possible for air

passages 80 and air outlets 84 without departing from the spirit and

scope of the present invention.

It will be appreciated that while air passages 80 are

shown as extending in pairs along the longitudinal length of the

nozzle inserts 70, the vertical orientation of the air outlets 84 may be

changed without departing from the spirit and scope of the present

invention. For example, each air passage 80 may angle inwardly

toward the longitudinal axis of a respective nozzle insert 70. - 22 -

Alternatively, only the outermost air passages 80 on the lower

surface 66 of pattern plate 24 may be angled inwardly to control side

edge formation of the dispensed pattern. Additionally, while the air

outlets 84 are preferably aligned on the same axis as the material

outlets 76, other orientations of the air outlets 84 are possible that

provide the same advantageous function of separating the strands

27a during the draw down phase and oscillating the fibers 27b in a

generally cross-machine direction as described in detail below. For

example, the air passages 84 may be staggered relative to the

common axis of the material outlets 76 or positioned slightly off the

common axis of the material outlets 76. Moreover, while a pair of air

outlets 84 is preferred with each material outlet 76, more air outlets

84 per material outlet 76 are possible that provide the advantageous

functions described herein.

As shown with reference to Fig. 2, die block 22 includes

a stepped bore 85 and a supply passage 86 for delivering hot melt

adhesive from the adhesive cavity (not shown) of dispenser body 18

to the elongated adhesive distribution channel 62 of pattern die 24.

A valve seat 88, preferably made of carbide, is located in a lower

portion of the stepped bore 85 that cooperates with a ball 90 formed

on the lower end of a valve plunger 92 for providing controlled - 23 - continuous or intermittent supply of hot melt adhesive to the

adhesive distribution channel 62. In this way, hot melt adhesive may

be applied to the surface 28 of moving substrate 30 with well-defined

cut-on and cut-off edges through the material outlets 76 in

accordance with the present invention as will be described in more

detail below or as a continuous pattern. It will be appreciated by

those of ordinary skill in the art that while a single supply passage 86

is shown, the supply passage 86 may include two or more branches

(not shown) that fluidly communicate with adhesive distribution

panel 62. In this configuration of the supply passage 86, it is

contemplated that a single fastener 58 could be used to mount the

pattern die 24 and sealing plate 26 to the die block 22.

With further reference to Fig. 2, die block 22 preferably

includes a pair of air passages 94 (one shown) that extend between

the air connector bore 34 and the respective pair of transverse

passages 78 extending through the pattern die 24. In this way, the

pressurized air source 6 fluidly connected to air inlet line 32 and air

connector bore 34 delivers air through each of the air outlets 84

formed in the pattern die 24 during operation of the material

dispensing head 8 as will be described in more detail below. - 24 - As shown with reference to Fig. 2, sealing plate 26 is

mounted having a planar face 96 in engagement with face 61 of

pattern die 24 via the fasteners 58. Pattern die 24 is mounted having

opposite face 63 in engagement with vertical wall or surface 46 of

die block 22. It will be appreciated that fasteners 58 must be applied

with sufficient torque to provide the necessary fluid seals between

the sealing plate 26, pattern die 24 and die block 22 to prevent loss

of air or hot melt adhesive between the components of the modular

die assembly 20.

In operation of the material dispensing head 8, as best

understood with reference to Figs. 2-4, the die assembly 20 is

mounted above the surface 28 of moving substrate 30 with its

longitudinal axis positioned generally transverse to the direction of

travel of the substrate 30 (represented by directional arrows 98 in

Figs. 3A and 3B). Dispenser body 18 introduces hot melt adhesive

into an upper portion of the stepped bore 85 formed in the die block

22. With the ball 90 of valve plunger 92 in engagement with the

valve seat 88, adhesive is prevented from flowing into supply

passage 86 and through the series of aligned nozzle inserts 70. As

the valve plunger 92 is forced upwardly during operation of the

dispenser body 18 in a known manner to disengage ball 90 from seat - 25 - 88, hot melt adhesive is directed along flow paths defined by the

supply passage 86, adhesive distribution channel 62, transverse

passages 68, and adhesive passages 72 formed in the nozzle inserts

70. The hot melt adhesive is emitted through the material outlets 76

of the nozzle inserts 70 as strands 27a that are directed toward the

surface 28 of moving substrate 30. It will be appreciated by those

skilled in the art that while a single dispensing module 16 is

illustrated and described herein for applying fluid material such as

hot melt adhesive on substrate 30, a series of dispensing modules

16, each with its associated dispenser body 18 and die assembly 20,

may be mounted in side-by-side relationship to extend across a wide

range of substrate widths and thereby provide a wide range of

material dispensing pattern widths.

At the same time that hot melt adhesive is emitted

through the material outlets 76 in strand form, pressurized air is

directed along flow paths defined by the air passages 94, transverse

passages 78, vertically oriented air distribution channels 60a,

horizontally oriented air distribution channel 60b, transverse

passages 82, and air passages 80 formed through the lower surface

66 of pattern die 24. The pressurized air is emitted through the air - 26 - outlets 84 positioned on opposite sides of each material outlet 76, as

represented diagrammatically by arrows 100 in Fig. 4.

Further referring to Figs. 2, 3A, 3B, the pressurized air

emitted from each pair of air outlets 84 associated with a respective

material outlet 76 serves several functions. First, the pressurized air

from each air outlet pair draws down and attenuates each strand 27a

of hot melt adhesive as it emits from a material outlet 76. The

attenuated strands 27a preferably form fibers 27b having a diameter

of less than 200 microns on the surface 28 of the moving substrate

30 for hot melt dispensing applications. The pressurized air emitted

from each air outlet 84 also serves to separate adjacent strands 27a

during the critical draw down phase to reduce "shot" formation on

the moving substrate 30. Moreover, the pressurized air serves to

oscillate the fibers 27b generally in a plane defined by the air outlets

84 associated with each material outlet 76.

When the air outlets 84 are formed on the same axis as

the material outlets 76, the pressurized air causes the fibers 27b to

oscillate generally in a plane transverse to the travel direction 98 of

moving substrate 30 (i.e., in a cross-machine direction). The strands

27a are emitted from respective material outlets 76 and form side-by-

side fiber beams 102 (Figs. 3 and 3A) that overlap along adjacent - 27 - edges to define generally oval placement patterns 104 (Fig. 3B) of

hot melt adhesive on the upper surface 28 of moving substrate 30.

As each oval 104 has its longitudinal axis aligned generally

transverse to the travel direction 98 of moving substrate 30, and as

adjacent edges of the ovals 104 overlap, the deposited fibers 27b

blend to form a uniform hot melt adhesive pattern across the upper

surface 28 of moving substrate 30. While oval patterns 104 are

shown as the preferred displacement pattern to form a small

dispensing footprint for each material outlet 76, it will be appreciated

that other pattern cross-section shapes are possible.

To achieve a preferred uniform pattern of adhesive on

the moving substrate 30, a spacing is provided between adjacent

material outlets 76, designated D, in Fig. 4, preferably within the

range of about 0.050 and about 0.250 in. for hot melt adhesive

applications. Spacing values less than the preferred lower limit of

the range may cause adjacent strands 27a to interfere or entangle in

an undesirable fashion, while values above the preferred upper limit

of the range may not provide the necessary blending to achieve a

uniform pattern. Most preferably, the spacing D., is within the range

of about 0.100 and about 0.200 in. for hot melt adhesive applications. - 28 - A spacing is also provided between each air outlet 84

and its associated material outlet 76, designated D₂ in Fig. 4,

preferably within the range of about 0.015 and about 0.080 in. for hot

melt adhesive applications. Spacing values less than the preferred

lower limit of the range may result in a less stable formation of fibers

27b, while values above the preferred upper limit of the range may

not provide the necessary fiber oscillation amplitude to blend

adjacent fibers 27b to achieve a uniform pattern. Most preferably,

the spacing D₂ is within the range of about 0.030 and about 0.060 in.

for hot melt adhesive applications.

When material outlets 76 are formed having circular

cross-sectional shapes, a preferred diameter of the material outlets

76 is within the range of about 0.010 and about 0.030 in. for hot melt

adhesive applications. Material outlet side diameters less than the

preferred lower limit of the range may be susceptible to clogging,

while diameters above the preferred upper limit of the range may not

create sufficient backpressures necessary to produce consistent

diameter fibers 27b on the substrate 30. Most preferably, the

diameter of the material outlets 76 is within the range of about 0.016

and about 0.024 in. for hot melt adhesive applications. It will be

appreciated that other cross-sectional shapes for the material outlets - 29 - 76, such as square or rectangular cross-sectional shapes, and other

diameters are possible without departing from the spirit and scope of

the present invention.

When air outlets 84 are formed having a circular cross-

sectional shape, a preferred diameter of the air outlets 84 is within

the range of about 0.010 and about 0.050 in. for hot melt adhesive

applications. Air outlet diameters less than the preferred lower limit

of the range may not provide sufficient drawdown and formation of

the fibers 27b, while diameters above the preferred upper limit of the

range may not provide any further beneficial draw down or

attenuation of the strands 27a. Most preferably, the diameter of the

air outlets 84 is within the range of about 0.012 and about 0.030 in.

for hot melt adhesive applications. It will be appreciated that other

cross-sectional shapes for the air outlets 84, such as square,

crescent or rectangular cross-sectional shapes, and other side

dimensions are possible without departing from the spirit and scope

of the present invention.

In another embodiment of the present invention, as

best understood with reference to Figs. 5 and 6, a modified pattern

die 150 is shown. All other components of the die assembly 20 are

generally unchanged. In this embodiment, pattern die 150 preferably - 30 - includes six (6) bores 164 formed through the lower surface 166 of

the pattern die that extend upwardly and fluidly connect with the six

(6) transverse passages (one shown in Fig. 2) extending horizontally

inwardly from the adhesive distribution channel 62. The bores 164

are equidistantly spaced along the lower surface 166 and have a

circular cross-section. The bores 164 are also preferably aligned

along an axis that is generally parallel to the longitudinal axis of the

pattern die. The bores 164 are sized to receive respective tubular

inserts 170 that are inserted and frictionally engaged within the bores

164. Six (6) oblong bores 106 are formed through the lower surface

166 of the pattern die 150 that extend upwardly and fluidly connect

with the twelve (12) transverse passages 82 (one shown in Fig. 2)

extending horizontally inwardly from the horizontally oriented air

distribution channel 60b. The oblong bores 106 are equidistantly

spaced, and are preferably aligned with their respective longitudinal

axes aligned along an axis that is also generally parallel to the

longitudinal axis of the pattern die 150 and coincident with the axis

of bores 164. In this way, crescent-shaped air outlets 184 are formed

on opposite sides of each material outlet 176 by a wall 108 of the

oblong bores 106 and an outer cylindrical surface 1 10 of the tubular

inserts 170. The air outlets 184 and material outlets 176 function - 31 - substantially as described in detail above to draw down and

attenuate each strand 27a of hot melt adhesive as it emits from a

material outlet 176. The spacing distance D₂ between each air outlet

184 and a respective material outlet 176 is defined by the thickness

of the tubular wall 1 12 of the nozzle insert 170. It will be appreciated

that the oblong bores 106 of this embodiment eliminate the need to

form the twelve (12) air passages 80 associated with the pattern die

24 of Figs. 1 B-4, thereby simplifying overall manufacturing of the

pattern die.

In another alternative embodiment of the present

invention, as best understood with reference to Figs. 7, 7A and 8, a

modified pattern die 250 is shown. All other components of the die

assembly 20 are generally unchanged. In this embodiment, the

nozzle inserts 270 are slightly enlarged (Fig. 7A), and include an

annular air channel 214a and a pair of elongated, recessed air

channels 214b formed in the tubular wall 212 of the each nozzle

insert 270. The nozzle inserts 270 are received and frictionally

engaged in six (6) bores 264 formed through the lower surface 266

of the pattern die 250 as described in detail above. The annular air

channels 214a fluidly communicate with six (6) transverse passages

(not shown) extending horizontally inwardly from the horizontally - 32 - oriented air distribution channel 60b and fluidly connected to the

bores 264. Each pair of air channels 214b are preferably formed on

opposite sides of each adhesive passage 272 extending through the

nozzle insert 270. The nozzle inserts 270 are positioned in the six (6)

bores 264 with each pair of air channels 214b forming a pair of air

outlets 284 with a cylindrical wall of the bores 264. Preferably, each

pair of air outlets 284 is formed on opposite sides of a respective

material outlet 276, and air outlets 284 and material outlets 276 are

aligned along an axis that is generally parallel to the longitudinal axis

of the pattern die 250. The air outlets 284 and material outlets 276

function substantially as described in detail above to draw down and

attenuate each strand 27a of hot melt adhesive as it emits from a

material outlet 276. It will be appreciated that the tubular nozzle

inserts 270 of this embodiment reduce the number of transverse

passages 82 that need to be formed as well as eliminating the need

to form the twelve (12) air passages 80 associated with the pattern

die 24 of Figs. 1A-4, thereby also simplifying overall manufacturing

of the pattern die.

In yet another alternative embodiment of the present

invention, as best understood with reference to Figs. 9 and 10, a

modified pattern die 350 is shown. All other components of the die - 33 - assembly 20 are generally unchanged. In this embodiment, the

nozzle inserts 370 are slightly enlarged and include an annular air

channel 316a and a pair of elongated air channels 316b formed

through the tubular wall 312 of the each nozzle insert 370. The

nozzle inserts 370 are received and frictionally engaged in six (6)

bores 364 formed through the lower surface 366 of the pattern die

350 as described in detail above. The air channels 316a fluidly

communicate with six (6) transverse passages (not shown) extending

horizontally inwardly from the horizontally oriented air distribution

channel 60b and fluidly connected to the bores 364. Each pair of air

channels 316b are preferably formed on opposite sides of the

adhesive passage 372 extending through each nozzle insert 370.

The nozzle inserts 370 are positioned in the six (6) bores 364 with

each pair of air channels 316b forming a pair of air outlets 384 on

opposite sides of a respective material outlet 376. Preferably, the air

outlets 384 and material outlets 376 are aligned along an axis that is

generally parallel to the longitudinal axis of the pattern die 350. The

air outlets 384 and material outlets 376 function substantially as

described in detail above to draw down and attenuate each strand

27a of hot melt adhesive as it emits from a material outlet 376. It will

be appreciated that where the elongated air channels 316b are - 34 - preformed in each nozzle insert 370, the air channels 316b are sealed

off from the adhesive passage 372.

In still yet another alternative embodiment of the

present invention, as best understood with reference to Figs. 1 1 , 1 1A

and 12, a modified pattern die 450 is shown. All other components

of the die assembly 20 are unchanged. In this embodiment, each air

nozzle insert 470 includes an annular air channel 414a and a pair of

planar faces 418 formed on opposite sides of the nozzle insert 470.

The nozzle inserts 470 are received and frictionally engaged in six (6)

bores 464 formed through the lower surface 466 of the pattern die

450. The annular air channels 414a fluidly communicate with six (6)

transverse passages (not shown) extending horizontally inwardly

from the horizontally oriented air distribution channel 60b and fluidly

connected to the bores 464. The nozzle inserts 470 are positioned

in the six (6) bores 464 with each planar face 418 forming a pair of air

outlets 484 with a cylindrical wall of the bores 464. The air outlets

484 are formed on opposite sides of a respective material outlet 476,

and the air outlets 484 and material outlets 476 are preferably

aligned along an axis that is generally parallel to the longitudinal axis

of the pattern die 450. The air outlets 484 and material outlets 476

function substantially as described in detail above to draw down and - 35 - attenuate each strand 27a of hot melt adhesive as it emits from a

material outlet 476.

Referring now to Figs. 13 and 14, a modular die

assembly 500 in accordance with an alternative embodiment of the

present invention is shown. Die assembly 500 includes a die block

502 mounted to a lower end of a dispenser body 504, and a pattern

die 506 mounted to a lower planar face 508 of the die block 502. It

will be appreciated that the dispenser body 504 is similar in structure

and operation to the dispenser body 18 described in detail above.

Die block 502 has a mounting end 510 for fluidly connecting the die

assembly 500 to the dispenser body 504. The mounting end 510

extends into the adhesive cavity (not shown) of the dispenser body

504, and is sealed with walls of the adhesive cavity via an O-ring 512.

Die body 502 has a stepped bore 514 and a supply

passage 516 for delivering hot melt adhesive from the adhesive

cavity to an elongated adhesive distribution channel 518 formed in

the lower planar face 508 of the die body 502. A pair of air passages

520 (one shown in Fig. 13) is formed in the die body 502 to extend

between an air connector bore 522 and the lower planar face 508 of

the die body 502. A set of fasteners 524 extend through the die - 36 - body 502 and pattern die 506 to mount the die assembly 500 to the

dispenser body 504.

Pattern die 506 preferably includes a series of six (6)

bores 526 (one shown in Fig. 13) formed through a lower surface 528

of the pattern die that extend upwardly and fluidly connect with six

vertically oriented (6) passages 530 (one shown in Fig. 13) extending

from an upper planar face 532 of the pattern die 506. Bores 526

preferably have a circular cross-section and are preferably aligned

along an axis that is generally parallel to the longitudinal axis of the

pattern die 506. The bores 526 are also preferably spaced

equidistantly along the lower surface 528 of the pattern die 506, and

are sized to receive respective tubular nozzle inserts 534 that are

inserted and frictionally engaged within the bores 526. Each nozzle

insert 534 has an elongated adhesive passage 536 that extends

generally along the longitudinal axis of the nozzle insert. Each

adhesive passage 536 preferably has a uniform cross-sectional

shape between an upper surface 538 of the nozzle insert 534 and a

conically-shaped material outlet 540 formed at a lower end of each

nozzle insert 534 that extends below the lower surface 528 of pattern

die 506. Of course, the adhesive passages 536 could be tapered

within the spirit and scope of the present invention. - 37 - Pattern die 506 further preferably includes an elongated

air distribution channel 542 formed in the upper face 532 of the die

head. In accordance with one embodiment of the present invention,

the pattern die 506 includes a series of twelve (12) passages 544 (one

shown in Fig. 13) that are each fluidly connected at one respective

end to the air distribution channel 542. The other respective ends of

the passages 544 are fluidly connected to twelve (12) air passages

546 (Fig. 14) that are formed through the lower surface 528 of the

pattern die 506.

In operation, the die assembly 500 is mounted above a

surface 548 of a moving substrate 550 with its longitudinal axis

positioned generally transverse to the direction of travel of the

moving substrate 550 (represented by directional arrow 552 in Fig.

13). Dispenser body 504, similar to dispenser body 18 described in

detail above, introduces hot melt adhesive into an upper portion of

the stepped bore 514 formed in the die body 502. In an "on" state,

hot melt adhesive is directed along flow paths defined by the supply

passage 516, adhesive distribution channel 518, vertical passages

530, and adhesive passages 536 formed in the nozzle inserts 534.

The hot melt adhesive is emitted through material outlets 540 (Fig. - 38 - 14) of the nozzle inserts 534 as strands 554a that are directed toward

surface 548 of moving substrate 550.

At the same time that hot melt adhesive is emitted

through the material outlets 540 in strand form, pressurized air is

directed along flow paths defined by the air passages 520, air

distribution channel 542, passages 544, and air passages 546 formed

through the lower surface 528 of pattern die 502. The pressurized

air is emitted through air outlets 556 (Fig. 14) positioned on opposite

sides of each material outlet 540 as described in detail above. Die

assembly 500 is operable to emit the strands 554a of hot melt

adhesive that are drawn down and attenuated into fibers 554b for

deposition on the surface 548 of the moving substrate 550 as

described above with reference to the embodiment of the die

assembly 20 of Figs. 1 -1 2. It will be appreciated by those skilled that

the art that the nozzle inserts 534 and air passages 546 may be

modified to incorporate the configurations shown and described

above with reference to Fig. 1 -12. Moreover, it will be appreciated

that while nozzle inserts 534 are preferred, they may be replaced

with a series of adhesive passages drilled or otherwise formed in the

lower surface 528 of the pattern die 506. - 39 - Figs. 15, 15A and 16 illustrate a modular die assembly

600 in accordance with another alternative embodiment of the

present invention. Die assembly 600 is mounted to a lower end of a

dispenser body 602 and includes a die block 604 similar to the die

block 22 described in detail above, a distribution plate 606, a pattern

die 608, and a sealing plate 610. The distribution plate 606, pattern

die 608 and sealing plate 610 are mounted within a seat 612 defined

by a vertical wall or surface 614 and a horizontal wall or surface 616

formed in die block 604. It will be appreciated that the dispenser

body 602 is similar in structure and operation to the dispenser body

18 described in detail above.

As best understood with reference to Figs. 15 and 16,

each of the distribution plate 606, pattern die 608 and sealing plate

610 includes a respective pair of apertures 618 extending through

the die components for receiving a pair of fasteners 620 that mount

the components to the vertical wall 614 of die block 604. Distribution

plate 606 is mounted having a planar face 622 in engagement with

the vertical wall or surface 614 of die block 604, and includes a pair

of transverse air passages 624 extending through the plate 606 that

fluidly connect with a respective pair of air passages 626 (one shown

in Fig. 16) formed in die block 604. Distribution plate 606 further - 40 - includes a transverse adhesive passage 628 extending through the

plate 606 that fluidly connects with an adhesive supply passage 630

formed in die block 604 (Fig. 16). For purposes to be described in

greater detail below, a pair of vertically oriented air distribution

channels 632a, and an elongated, horizontally oriented air

distribution channel 632b, are formed in an opposite face 634 of

distribution plate 606.

Pattern die 608 is mounted having a planar face 636 in

engagement with the opposite face 634 of the distribution plate 606.

As will be described in greater detail below, pattern die 608 includes

respective upper and lower pairs of transverse air passages 638a and

638b that extend through the pattern die 608, with the upper pair of

air passages 638a fluidly connected to the pair of air passages 624 in

distribution plate 606, and each of the lower pair of air passages

638b fluidly connected to a respective one of the pair of vertically

oriented air distribution channels 632a formed in the face 634 of die

block 606. Pattern die 608 further includes an elongated, horizontally

oriented adhesive distribution channel 640 formed in face 636 that

fluidly connects with the transverse adhesive passage 628 formed in

distribution plate 606. - 41 - As shown in Figs. 15A and 16, pattern die 608

preferably includes six (6) adhesive passages 642, drilled or

otherwise formed, that extend from a lower end 644 of the pattern

die 608 and fluidly connect with the elongated, horizontally oriented

adhesive passage 640 formed in pattern die 608. Each adhesive

passage 642 terminates in a material outlet 646 at the lower end 644

of the pattern die 608. The material outlets 646 are preferably

aligned along a common axis and are equidistantly spaced at the

lower end 644 of the pattern die 608. Of course, it will be

appreciated that the adhesive passages 642 may be replaced with

tubular nozzle inserts (not shown), as described in detail above,

without departing from the spirit and scope of the present invention.

Air outlets 648 are formed between each material outlet 646 by

respective angularly-shaped, upper and lower cutouts 650a and 650b

formed on the lower end 644 and on opposite faces 636 and 652 of

the pattern die 608 for purposes to be described in detail below.

As shown in Figs. 15 and 16, the sealing plate 610

includes a pair of elongated, vertically oriented air distribution

channels 654a and an elongated, horizontally oriented air distribution

channel 654b formed in plate face 656 that engages face 652 of

pattern die 608. Each of the vertically oriented air distribution - 42 - channels 654a fluidly connects with an upper and lower air passage

638a, 638b of each respective pair of air passages 638a, 638b formed

in the pattern die 608. As shown phantom in Fig. 16, the upper

cutouts 650a on one side of pattern die 608 fluidly connect with the

horizontally oriented air distribution channel 654b of sealing plate

610, while the upper cutouts 650a on the other side of pattern die

608 fluidly connect with the horizontally oriented air distribution

channel 632b of distribution plate 606.

In operation, the die assembly 600 is mounted above a

surface of a moving substrate (not shown) with its longitudinal axis

preferably positioned generally transverse to the direction of travel

of the moving substrate (not shown). In an "on" state of dispenser

body 602, hot melt adhesive is directed along flow paths defined by

the supply passage 630, adhesive passage 628, adhesive distribution

channel 640, and vertically oriented adhesive passages 642. The hot

melt adhesive is emitted through the material outlets 646 as strands

(not shown) that are directed toward the surface of moving substrate

(not shown), similar to strands 27a described in detail above.

At the same time that hot melt adhesive is emitted

through the material outlets 646 in strand form, pressurized air is

directed along flow paths defined by the air passages 626, air - 43 - passages 624, upper air passages 638a, vertically oriented air

distribution channels 654a, horizontally oriented air distribution

channel 654b, lower air passages 638b, vertically oriented air

distribution channels 632a, and horizontally oriented air distribution

channel 632b.

As described above, the horizontally oriented air

distribution channel 654a of distribution plate 606 fluidly connects

with upper cutouts 650a on one side of pattern die 608, while the

horizontally oriented air distribution channel 654b of sealing plate

610 fluidly connects with upper cutouts 650a on the opposite side of

pattern die 608. In this way, pressurized air is emitted through the

air outlets 648 formed between each of the material outlets 646. The

air outlets 648 and material outlets 646 function substantially as

described in detail above to draw down and attenuate each strand

(not shown) of hot melt adhesive as it emits from a material outlet

646.

It will be appreciated by those skilled in the art that the

material dispensing system 2 of the present invention provides

improved control of dispensed material patterns on a moving

substrate. The decreased volume of air required to produce a

uniform layer of material on the substrate reduces the formation of - 44 - undesirable "fly", and also reduces operational and maintenance

costs of the material dispensing system 2. Additionally, the ability to

increase the spacing between adjacent material outlets 76 per

dispensing module 16 to form a uniform layer on the substrate (or to

reduce the number of material outlets 76 per dispensing module 16)

reduces the formation of undesirable "shot" during the critical draw

down phase. The orientation of the dispensed pattern in narrow

beams reduces the dispensed pattern footprint for improved pattern

control. Moreover, the orientation and operation of the material

outlets 76 and air outlets 84 improves the ability to modularize the

dispensing system.

While the present invention has been illustrated by a

description of various embodiments and while these embodiments

have been described in considerable detail, it will be appreciated by

those of ordinary skill in the art that departures may be made from

such details without departing from the spirit or scope of applicants'

invention. For example, while the terms "upper", "lower", "above"

and "below" have been used herein to discuss one embodiment of

the present invention, it will be understood that other orientations of

the die components and substrate are possible without departing

from the spirit and scope of the present invention. The invention in - 45 - its broader aspects is therefore not limited to the specific details,

representative apparatus and method, and illustrative example

shown and described.

While the present invention has been illustrated by a

description of various embodiments and while these embodiments

have been described in considerable detail, it is not the intention of

the applicants to restrict or in any way limit the scope of the

appended claims to such detail. Additional advantages and

modifications will readily appear to those skilled in the art. The

invention in its broader aspects is therefore not limited to the specific

details, representative apparatus and method, and illustrative

example shown and described. Accordingly, departures may be

made from such details without departing from the spirit or scope of

applicants' general inventive concept.

Having described the invention, what is claimed is:

Claims

- 46 - 1. A system for dispensing liquid material onto a moving

substrate, comprising :

a source of liquid material;

a source of pressurized air; and

a liquid dispenser fluidly connected to said source of

liquid material and said source of pressurized air, said liquid

dispenser having a plurality of liquid material outlets spaced along a

common axis at one end thereof for dispensing a plurality of strands

of liquid material toward the substrate, and a pair of air outlets

associated with each of said liquid material outlets for emitting

pressurized air operable to oscillate the dispensed strands in

directions predominantly parallel with the common axis during flight

toward the substrate and forming an overlapping pattern of liquid

material on the moving substrate.

2. The system of claim 1 , wherein each of said air outlets

is aligned along the common axis of said liquid material outlets.

- 47 - 3. The system of claim 2, wherein each of said air outlets

of a respective pair has a longitudinal axis that angles inwardly

toward a longitudinal axis of a respective one of said liquid material

outlets.

4. The system of claim 1 , wherein each of said air outlets

of a respective pair is arranged on diametrically opposite sides of a

respective one of said liquid material outlets.

5. The system of claim 4, wherein each of said air outlets

of a respective pair has a longitudinal axis that angles inwardly

toward a longitudinal axis of a respective one of said liquid material

outlets.

6. The system of claim 1 , wherein each of said air outlets

is arranged offset from the common axis of said liquid material

outlets.

7. The system of claim 6, wherein said plurality of air

outlets are arranged in staggered relationship relative to the

common axis of said liquid material outlets. - 48 -

8. The system of claim 6, wherein each of said air outlets

of a respective pair has a longitudinal axis that angles inwardly

toward a longitudinal axis of a respective one of said liquid material

outlets.

9. The system of claim 1 , wherein each of said air outlets

of a respective pair has a longitudinal axis that angles inwardly

toward a longitudinal axis of a respective one of said liquid material

outlets.

- 49 - 10. The system of claim 1 , wherein said liquid dispenser

further comprises:

a dispenser body adapted to be fluidly connected to a

source of liquid material; and

a die assembly mounted to said dispenser body and

having a die block adapted to be fluidly connected to the source of

liquid material and a source of pressurized air, and a pattern die

mounted to said die block having a plurality of liquid material outlets

spaced along a common axis at one end thereof for dispensing a

plurality of strands of liquid material toward the substrate, and a pair

of air outlets associated with each of said respective liquid material

outlets for emitting pressurized air operable to oscillate the

dispensed strands in directions predominantly parallel with the

common axis during flight toward the substrate and forming an

overlapping pattern of liquid material on the moving substrate.

- 50 -

1 1. A pattern die for use in a system to dispense liquid

material onto a moving substrate, comprising :

a plurality of liquid material outlets spaced along a

common axis at one end thereof for dispensing a plurality of strands

of liquid material toward the substrate, and a pair of air outlets

associated with each of said respective liquid material outlets for

emitting pressurized air operable to oscillate the dispensed strands

in directions predominantly parallel with the common axis during

flight toward the substrate and forming an overlapping pattern of

liquid material on the moving substrate.

12. The pattern die of claim 1 1 further comprising a

plurality of tubular nozzle inserts received in said pattern die that

each define a respective one of said liquid material outlets.

13. The pattern die of claim 12 further comprising a pair of

elongated bores formed in said pattern die and associated with each

of said tubular nozzle inserts that each defines a respective pair of

said air outlets. - 51 -

14. The pattern die of claim 13, wherein each of said

elongated bores of a respective pair is arranged on diametrically

opposite sides of a respective one of said tubular nozzle inserts.

15. The pattern die of claim 12, wherein each of said

tubular nozzle inserts includes a pair of elongated bores formed

within a tubular wall thereof that each defines a respective pair of

said air outlets.

16. The pattern die of claim 15, wherein each elongated

bore of a respective pair is arranged on diametrically opposite sides

of a respective one of said tubular nozzle inserts.

17. The pattern die of claim 12, wherein each of said

tubular nozzle inserts includes a pair of air channels recessed in a

tubular wall thereof that each defines a respective pair of said air

outlets.

18. The pattern die of claim 17, wherein each recessed air

channel of a respective pair is arranged on diametrically opposite

sides of a respective one of said tubular nozzle inserts. - 52 -

19. The pattern die of claim 1 1 further comprising a first

plurality of elongated bores spaced along the common axis, and a

second plurality of elongated bores in registry with and intersecting

said first plurality of elongated bores.

20. The pattern die of claim 19 further comprising a

plurality of tubular nozzle inserts received in said first plurality of

elongated bores that each defines a respective one of said liquid

material outlets.

21 . The pattern die of claim 20, wherein each of said

second plurality of elongated bores defines, in combination with a

wall of a respective one of said tubular nozzle inserts, a respective

pair of said air outlets associated with each respective one of said

liquid material outlets.

22. The pattern die of claim 1 1 further comprising a

plurality of elongated bores spaced along the common axis. - 53 -

23. The pattern die of claim 22 further comprising a

plurality of tubular nozzle inserts received in said plurality of

elongated bores that each define a respective one of said liquid

material outlets, and wherein each of said tubular nozzle inserts

includes a pair of planar faces that, in combination with a wall of a

respective elongated bore, define a respective pair of said air outlets.

24. The pattern die of claim 22, wherein each of said

plurality of elongated bores defines a respective one of said liquid

material outlets.

- 54 - 25. A method of dispensing liquid material onto a moving

substrate comprising the steps of:

dispensing the liquid material in a plurality of spaced

apart strands along a common axis toward the substrate;

maintaining each strand separate while drawing down

and alternating each strand;

forming a plurality of side by side beams of fibers

having a diameter less than 200 microns;

oscillating the side by side fiber beams in directions

predominantly parallel with the common axis during flight towards

the substrate to overlap edges of adjacent fiber beams; and

blending the overlapping fiber beams on the substrate

to form a uniform pattern.