CA2021401A1 - Method for applying adhesive to the waist reinforcing material of disposable garments - Google Patents
Method for applying adhesive to the waist reinforcing material of disposable garmentsInfo
- Publication number
- CA2021401A1 CA2021401A1 CA 2021401 CA2021401A CA2021401A1 CA 2021401 A1 CA2021401 A1 CA 2021401A1 CA 2021401 CA2021401 CA 2021401 CA 2021401 A CA2021401 A CA 2021401A CA 2021401 A1 CA2021401 A1 CA 2021401A1
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- Prior art keywords
- adhesive
- tape material
- elongated
- depositing
- fiber
- Prior art date
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Abstract
Method For Applying Adhesive To the Waist Reinforcing Material of Disposable Garments Abstract of the Disclosure A method of forming tape material, and particularly heat sensitive tape material of the type used to form a reinforcing patch at the waist portion of a disposable diaper or similar garment, comprising depositing one or more side-by-side spiral patterns of an elongated adhesive fiber onto a surface of the tape material at a relatively low application temperature.
Each spiral pattern of adhesive comprises longitudi-nally extending, overlapping loops of the adhesive fibers which provide sufficient bond strength for the tape material while reducing the quantity of adhesive required.
Each spiral pattern of adhesive comprises longitudi-nally extending, overlapping loops of the adhesive fibers which provide sufficient bond strength for the tape material while reducing the quantity of adhesive required.
Description
~21401 Method For Applying Adhesive To the Waist Reinforcinq Material of Disposable Garments Field of the Invention This invention relates to the manufacture of disposable garments, and, more particularly, to an in-line method of applying adhesive to the sections of reinforcing, tape material which are attached to the polyethylene backing sheet of disposable garments at the waist area thereof. . :
Backqround of the Invention Disposable absorbent garments such as :
disposable diapers and adult incontinence briefs have met with widespread use to absorb and contain body exudates and thus prevent soiling or wetting of clothing, bedding and other articles. Com~ercially available disposable diapers, for e~ample, are unitary 15 pre-shaped and pre-folded garments which include a -moisture-impervious backing layer, a body contacting layer or liner and a moisture-absorbent core there-between. Elasticized leg openings are formed at the sides of the diaper to improve comfort of the garment 20 and its ability to contain waste material. -~, . . .. . .
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Backqround of the Invention Disposable absorbent garments such as :
disposable diapers and adult incontinence briefs have met with widespread use to absorb and contain body exudates and thus prevent soiling or wetting of clothing, bedding and other articles. Com~ercially available disposable diapers, for e~ample, are unitary 15 pre-shaped and pre-folded garments which include a -moisture-impervious backing layer, a body contacting layer or liner and a moisture-absorbent core there-between. Elasticized leg openings are formed at the sides of the diaper to improve comfort of the garment 20 and its ability to contain waste material. -~, . . .. . .
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Disposable garments of this type are secured about the waist of the wearer with adhesive tape tabs located at the back waist portion of the garment whlch are engageable with the bac~ing sheet of the garment along its front waist portion. In most cases, it is desirable to allow these adhesive tape tabs to be fastened and refastened several times to permit an adjustment of the fit of the garment on the wearer and to permit inspection of the garment. The polyethylene material which is used to form the moisture-imperviouS
backing sheet of such garments, however, tends to tear if the tape tabs are unfastened for any purpose. To solve this problem, a patch or section of reinforcing material has been secured to the outer surface of the polyethylene backing sheet at the front waist section of disposable garments for attachment to the tape tabs. This reinforcing material, e.g., polypropylene or a similar material, permits the tape tabs to be fastened and unfastened several times without render-ing the garment unserviceable.
Although it is desirable to provide asection of reinforcing material at the front waist portion of the disposable garment, diaper manufac-turers have been confronted with the problem of developing a method and apparatus for efficiently and economically attaching such reinforcing material to the garment. In some methods, for example, the -` 202~4~
patches or sections of reinforcing material are obtained from rolls wherein the reinforcing material is first coated with adhesive and then wound upon itself. During the garment manufacturing operation, these rolls are unwound and cut to si%e to form the patches or sections which are subsequently adhered to the appropriate location on the polyethylene backing sheet of the garment.
Wound rolls of reinforcing material have proven to be unsatisfactory for a number of reasons.
One problem is that the adjacent layers in the roll become adhesively bonded to one another and can be difficult to separate as the roll is unwound during the manufacturing process. If the adhesive attachment between the several layers of the roll is too strong, the polyethylene material may fracture or tear during unwinding. A lesser adhesive bond strength to reduce this problem can result in insufficient attachment of the reinforcing material when it is subsequently applied to the backing sheet. Strengthening of the reinforcing material itself to avoid tearing often results in excessive costs, or a finished garment having an unacceptable appearance.
Another attempt to avoid attachment between adjacent layers of a wound roll of reinforcing mate-rial involves the application of a non-stick release coating onto the adhesive. The problem with this 2~2~ 40~
approach, however, is that the release coating can reduce the adhesive bond strength to such an extent that the reinforcing material does not suitably adhere to the disposable garment. Alternatively, a separate layer of non-stick material has been interposed between adjacent layers of the wound roll of reinforc-ing material. This non-stick material avoids attach-ment between the layers of the roll, but adds to material costs and also requires an additional process step to remove the non-stick layer from the roll as it is unwound during the garment manufacturing operation.
In order to avoid the types of problems mentioned above with a wound roll of adhesive coated reinforcing material, methods have been proposed to apply the adhesive onto the reinforcing material in-line with the manufacture of the disposable gar-ment. U.S. Patent No. 4,795,510 to Wittrock et al, for example, discloses an in-line method for applying reinforcing material to the polyethylene backing sheet of a disposable garment in which the reinforcing material is unwound from an endless roll, adhesive is applied to the moving web or sheet of reinforcing material and then individual sections of adhesively coated reinforcing material are formed and attached at longitudinally spaced locations onto a moving sheet of the polyethylene material which forms the backing sheet of the disposable garment. In this method, a 2Q~
series of adhesive dispensers are mounted side-by-side to a carrier or support head immediately above the moving sheet of reinforcing material and are effective to apply a continuous coating of hot melt, thermo-plastic adhesive along the entire length and width ofthe moving sheet. These adhesive dispensers typically include slot nozzles which contact the moving rein-forcing material during operation to ensure that a uniform adhesive coating is applied across the entire transverse dimension of the moving reinforcing mate-rial.
Several problems are created with the application of hot melt adhesive to the reinforcing material in the manner disclosed in Patent No.
4,795,510. First, the application temperature of the continuous coating of hot melt adhesive is approxi-mately 300F which can cause the heat sensitive reinforcing material, i.e., polypropylene, to deform or wrinkle. As a result, chill rollers must be positioned immediately downstream from the adhesive dispensers to reduce the temperature of the hot melt adhesive before it damages the reinforcing material.
The addition of chill rollers to the manufacturing apparatus adds expense and complicates the adhesive application process.
Another problem with the method and appara-tus for applying adhesive to the reinforcing material --- ~ .. . .. . . . . . . . . .
2021 ~Bl disclosed in the 4,795,510 patent is that the slot nozzles employed by the adhesive dispensers must be placed in contact with the reinforcing material to obtain the desired pattern definition at the edges of the reinforcing material. This contact between the slot nozzles and reinforcing material creates wear on the slot nozzles requiring relatively frequent re-placement thereof. Additionally, mechanisms must be provided to raise and lower the adhesive dispensers with respect to the reinforcing material so that the dispensers can be lifted from the surface of the reinforcing material when the manufacturing process is interrupted or terminated for a period of time. Such mechanisms add additional cost to the system and complicate its operation.
Still another problem with the method of applying adhesive described above is that a relatively large quantity of pressure sensitive, hot melt thermo-plastic adhesive is required to provide a continuous coating across the entire length and width of the sheet of reinforcing material. Moreover, this pres-sure-sensitive, hot melt adhesive is highly viscous and "gummy". It has been found that difficulties are encountered when the sheet of reinforcing material having an uninterrup~ed continuous coating of adhesive is cut into separate sections or patches for applica-tion to the polyethylene backing sheet of a disposable ~ -7- ~2~9~
garment because the adhesive tends to dull and gum up the knife blades which cut such material. This creates maintenance problems and may require periodic stoppage of the manufacturing line to clean the adhesive from the knife blades. -~
Summary of the Invention It is therefore among the objectives of this invention to provide a method for applylng adhesive to tape material such as the reinforcing material applied to the waist portion of a disposable garment, which reduces the quantity of adhesive applied to the reinforcing material, which eliminates the need for ~`~
chill rollers, which reduces dulling and clogging of the knife blades used to cut the reinforcing material, `
which eliminates mechanisms for moving adhesive dispensers with respect to the reinforcing material and which increases the efficiency of the manufactur-ing operation while reducing costs. .
These objectives are accomplished in the method of this invention wherein a series of adhesive dispensers are mounted side-by-side immediately above a moving sheet or web of tape material such as the reinforcing material attached to the front waist portion of disposable garments. Each adhesive dis-penser is effective to extrude a relatively thick bead of adhesive toward the tape or reinforcing material and to impact the outer periphery of such extruded - ':
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-~- 2~2140 beaas wlth jets of air. ~he -drr ~ets are eff~ctive t attenuate or stretch such adhesive beads to form a relatively thin, elongated adhesive fiber, and to impart a twisting or rotational motion to such elon-gated fibers. In the presently preferred embodiment, the air jets of adjacent adhesive dispensers are oriented with respect to the path of the extruded adhesive beads such that the elongated adhesive fiber .,, .,. ~ ~
produced by one adhesive dispenser rotates in a clockwise direction and the elongated adhesive fiber produced by an adjacent adhesive dispenser rotates in a counterclockwise direction. These counter-rotating adhesive fibers from adjacent dispensers are deposited in side-by-side spiral patterns across the entire width of the reinforcing material as it moves longi-tudinally beneath the dispensers.
A number of advantages are obtained with the method of applying adhesive of this invention compared to prior art techniques of applying adhesive to heat sensitive tape or reinforcement such as disclosed in Patent No. 4,795,510. The elongated adhesive fiber produced by each adhesive dispenser herein is rela-tively thin compared to extruded adhesive beads and tends to retain much less specific heat upon applica-tion onto a substrate. As a result, the applicationtemperature of the elongated adhesive fibers upon impact with the tape or reinforcing material is 4~
g sufficiently low to avoid or reduce heat damage, i.e., wrinkling or buckling, to the heat sensitive tape or reinforcing material. In the manufacture of dispos-able garments, for e~ample, this reduction in applica-tlon temperature of the hot melt adhesive has resulted in the elimination of chill rollers downstream from the adhesive applicators.
Another advantage of the method of this invention is a reduction in the quantity of adhesive which is required to obtain an acceptable bond between the reinforcing material and polyethylene backing sheet of a disposable garment. The spiral pattern of adhesive obtained from each adhesive dispenser com-prises a series of loops or spirals which overlap one another in the longitudinal direction. Instead of a continuous coating of adhesive across the entire width and length of the tape or reinforcing material, the adhesive dispensers of this invention apply overlap-ping loops or spirals of a thin, elongated adhesive fiber to such material. This substantially reduces the amount of adhesive utilized, while providing sufficient bond strength between the reinforcing material and the backing sheet of a disposable garment or an~ other substrate.
The reduction in the quantity of adhesive applied to the tape or reinforcing material obtained by this invention also produces benefits when the -10- 2~
material is subsequently cut. A lesser quantity of adhesive on the tape or reinforcing material reduces the wear or damage to the knife blades which cut such material, and also lessens the problem of clogging of the ~nife blades with adhesive as the cutting opera-tion is performed. The expense of replacing or repairing worn knife blades is reduced, and the maintenance time associated with cleaning the blades during a manufacturing operation is also reduced.
A further advantage of this invention is that the adhesive dispensers are mounted in a fixed position above the moving tape or reinforcing mate-rial. Because there is no contact between the nozzle portion of the adhesive dispensers herein and the tape or reinforcing material, problems of wear and other contact damage with the slot nozzles employed in other methods have been eliminated. Moreover, no mechanisms are required to extend or retract the adhesive dis-pensers relative to the reinforcing material in the method of this invention because they are fixedly mounted in position and can remain in place when movement of the reinforcing material is stopped.
Description of the Drawinqs The structure, operation and advantages of the presently preferred embodiment of this invention will become further apparent upon consideration of the .: ~ : ~ : . . :: , .
::,: . .: . ~ : . , . ' ' Q~ 401 following description, taken in conjunction with the accompanying drawings, wherein~
Fig. 1 is a schematic perspective view of a disposable garment having a section of tape or rein-forcing material attached at the front waist portionthereof;
Fig. 2 is a schematic perspective view of an apparatus for adhering strips of reinforcing material to the polyethylene backing sheet of a disposable garment; and Fig. 3 is an enlarged front elevational view in partial cross section of the adhesive dispensing device adapted for use with the apparatus of Fig. 2.
Detailed Description of the Invention .
Referring now to the Figs., a method and apparatus is depicted for applying pressure sensitive, hot melt thermoplastic adhesive onto an endless length or web of tape material. In the illustrated embodi~
ment, the method is particularly adapted for the application of adhesive onto the reinforcing material 10 which is used in the formation of a reinforcing section 12 in a disposable diaper 14. It should be understood, however, that the method of this invention is applicable to the formation of tape material per se.
As shown in Fig. 1, the disposable diaper 14 comprises a moisture-impervious backing sheet 16 and a ,, ~, , .
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~ 12- 2021401 body contactinq liner or layer 18 having a non-woven core or pad (not shown) therebetween. The diaper 14 is formed with a front waist section 20, a rear waist section 22 which mounts opposed tape tabs 24, 26 and elasticized leg openings 28 and 30 on either side of the centerline of the diaper 14. In this application, the method herein is directed to applying pressure sensitive, hot melt thermoplastic adhesive to one side of the tape section 12 which is adhered to the front waist section 20 of the diaper 14. The tape section 12 permits the tape tabs 24, 26 of the rear waist section 22 to be attached and reattached thereto as the diaper 14 is secured to the wearer without damage to the backing sheet 16 or any other part of the diaper 14.
Referring now to Fig. 2, a schematic view is illustrated of one form of an apparatus 32 for apply-ing adhesive to one side of an endless length or web : .: :
of reinforcing material 10 and for cutting such mate-rial 10 into individual tape sections or patches 12 which are then attached to a polyethylene material 34 used to form the backing sheet 16 of the disposable diaper 14. Many of the structural details of the apparatus 32 form no part of this invention per se and are discussed only briefly herein. Reference should be made to U.S. Patent No. 4,795,510 to Wittrock et al for a detailed explanation of the operation of ~ " . ~ . . . : . .
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apparatus 32. For purposes of the presen~ discussion, the apparatus 32 comprises structure for withdrawing the polyethylene material 34 from a roll 35 and feeding it past an attachment station 36 where indi-vidual tape sections 12 are adhered thereto at longi-tudinally spaced locations therealong. The poly-ethylene material 34 is fed through a pair of guide rollers 40, 42, over a dancer roller 44 and then around a third guide roller 46 to a pair of counter-rotating nip rollers 48, 50 located immediatelyupstream from the attachment station 36. The poly-ethylene material 34 passes through the attachment station 36 where the individual tape sections 12 are adhered thereto, as discussed below, and then con~
tinues to a second pair of counter-rotating nip rollers 52, 54 which feed the material 34 to another station (not shown) for further processing.
Referring now to the top portion of Fig. 2, the reinforcing material 10 is fed over a first guide roller 60, between a pair of nip rollers 62, 64, and over spaced guide rollers 66 and 68 to an idler roller 70 carried by a support frame 72. The reinforcing material 10 is directed from the idler roller 70 between guide rollers 71, 73, ovér an idler roller 75 and tc a position beneath an adhesive applicator 74 discussed in detail below. This adhesive applicator 74 is effective to apply a number of side-by-side, - -14- 20214~1 longitudinally extending spiral patterns 138, 142 of adhesive onto the reinforcing material 10. After moving from the adhesive applicator 74, the reinf~rc-ing material 10 passes over a guide roller 78.
The reinforcing material 10 moves from the guide roller 78 over feed roller 80 to a turn bar 82.
The turn bar 82 directs the reinforcing material 10 to the attachment station 36 which comprises feed rollers 84, 86, a tension roller 88, a knife roll 90, a vacuum anvil roll 92, and a stomper roll 94. The reinforcing material 10 is directed by the feed rollers 84, 86 to the knife roll 90 which is effective to cut the reinforcing material 10 in a direction transverse to the path of movement of such material 10 thus forming individual tape sections or patches 12 which are held on the vacuum anvil roll 92 by the application of vacuum. These individual tape sections 12 are brought into a position beneath the moving polyethylene material 34 in alignment with the stomper 94 by rotation of the vacuum anvil roll 92. The stomper 94 is effective to press the polyethylene material 34 against the vacuum anvil roll 92 and the tape sections 12 it supports so each of the tape sections 12 is adhered to the bottom surface of the polyethylene material 34. As shown in Fig. 2, the tape sections 12 are longitudinally spaced along the polyethylene ~ . . . . .. . . . .. .
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material 34 in areas which form the front waist section of the finished disposable diaper 14.
Referring now to Figs. 2 and 3, the adhesive applicator 74 of this invention is illustrated in detail. In the presently preferred embodiment, this adhesive applicator 74 is of the type disclosed in U.S. Patent No. 4,815,660 to Boger, owned by the assignee of this invention, which is incorporated by reference in its entirety herein. The adhesive applicator 74 includes a manifold or carrier head 96 which mounts four adhesive dispensers s8a-d in side-by-side relation. While four adhesive dispensers 98a-d are illustrated in the Figs., it is contemplated that essentially any number of dispensers could be utilized depending upon the width of the reinforcing material 10 to be coated with adhesive.
The structure and operation of alternating adhesive dispensers 98a, c and g8b, d, respectively, are identical to one another. For purposes of the present discussion, only dispenser 98c is illustrated in detail and the operation of alternating dispensers is briefly described. Reference should be made to Patent No. 4,815,660 for a detailed discussion of same.
The adhesive dispenser 98c, for example, mounts a nozzle 100 formed with an adhesive passageway 102 which communicates with a source of adhesive (not :: . ' : '. ' ', .' '' .: ~ -.' -16- 202~01 shown) connected to the carrier head 96 The other end of adhesive passageway 102 terminates at an adhesive discharge opening 104. An air delivery passageway 106 is formed in nozzle 100 which is connected to an annular chamber 108 at the base of the nozzle 100. The air delivery passageway 106 is supplied with pressurized air from the carrier head 96 for purposes to become apparent below. Preferably, nozzle lO0 is formed with a reduced diameter portion having external threads which mate with internal threads formed in a cap 112. As described below, a first nozzle plate 114 is mounted by cap 112 to adhesive dispensers s8a and c, and a second nozzle plate 116 is mounted by cap 112 to the nozzle lO0 of adhesive dispensers 98b and d.
Each nozzle plate 114, 116 is formed with a throughbore 118, as shown with reference to dispenser 98c, having an inlet end connected to the adhesive passageway 102 of nozzle 100 and a discharge outlet 120. A number of air jet bores 122 are formed in nozzle plate 114, and a li~e number of air jet bores 123 are formed in nozzle plate 116. The air jet bores 122 and 123 of nozzle plates 114 and 116, respec-tively, are each connected to the annular chamber 108 of air delivery passageway 106 in nozzles 100 and have discharge outlets which are angled with respect to the longitudinal axis of the throughbore 118. The nozzle plates 114, 116 are each carried on an annular seat 128 formed in the caps 112. The caps 112 are threaded onto the lowermost end of the nozzles 100 so that the throughbore 118 of each nozzle plate 114, 116 communl~
cates with the discharge opening 104 of adhesive passageway 102, and the inlets of the air jet bores 122 and 123 communicate with the annular chamber 108 of air delivery passageway 106.
The operation of the adhesive applicator 74 is as follows. Heated hot melt thermoplastic adhesive is introduced into the adhesive passageway 102 of each nozzle 100 from the carrier head 96. An air-operated plunger 130, the lowermost end of which is illustrated in dispenser 98c of Fig. 3, is operative to permit the passage of the adhesive from the nozzle 100 into the throughbore 118 of each nozzle plate 114, 116. The hot melt adhesive is extruded through the discharge outlet 120 in nozzle plates 114 forming a first adhesive bead 132 ejected from dispensers 98a and c, and the hot melt adhesive extruded through the dis-charge outlet 120 in nozzle plates 116 forms a second adhesive bead 134 ejected from dispensers 98b and d.
At the same time the adhesive beads 132, 134 are extruded from the nozzle 100 of each dispenser 98a-d, pressurized air is directed through the air delivery passageway 106 and annular chamber 108 to the air jet :,, :
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bores 122 and 123 in the nozzle plates 114, 116, respectively.
As discussed in detail in U.S. Patent No.
4,815,660, the air jet bores ~22 of the nozzle plate 114 are angled relative to the longitudinal axis of the throughbore 118 therein so that the jets of air flowing through air jet bores 122 impact each first adhesive bead 132 substantially tangent to its outer periphery at a point below the discharge outlet 120 of the throughbore 118. The air ejected from the air jet bores 122 performs two functions. First, the air jets attenuate or stretch each first adhesive bead 132 to form an elongated adhesive strand or fiber 136 for deposition onto the reinforcing material 10.
Secondly, the air jets from the ~ores 122 impart a clockwise rotational or twisting motion to the elon-gated fibers 136, shown by the arrows in Fig. 3, so that the elongated fiber 136 from each dispenser 98a and c is deposited in a well defined, compact spiral pattern 138 onto the reinforcing material 10. See also Fig. 2.
The orientation of air jet bores 123 in the nozzle plates 116 of adhesive dispensers 98b and d is essentially the mirror image of that of the air jet bores 122 in the nozzle plate 114 of adhesive dispen-sers 98a and c. Jets of air from the air jet bores 123 impact the outer periphery of the second adhesive ~ . . ~, . . - ,-. . ,- ~ .. .. . . . . . .
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` 19 bead 134 extruded from the nozzle plate 116 of each dispenser s8b and d to form elongated adhesive fibers 140 which are rotated in a counterclockwise direction, instead of the clockwise direction of rotation of the adhesive fibers 136. The adhesive dispenser 98b produces a spiral pattern 142 of the adhesive fiber 140 located between the two spiral patterns 138 of adhesive fibers 136 from adhesive dispensers 98a and b, and the adhesive dispenser g8b produces a spiral pattern 142 of adhesive fiber 140 located adjacent to the spiral pattern 138 of adhesive dispenser 98c. As discussed in detail in Patent No. ~,815,660, the counter-rotating adhesive fibers 136 and 140 which produce spiral patterns 138 and 142, respectively, contact one another at or near the top of the surface of the reinforcing material 10. Because adjacent adhesive fibers 136 and 140 are rotating in opposite directions, they do not interfere with one another upon contact with the reinforcing material 10 and produce little or no turbulence or eddies which can disrupt the pattern or produce uneven application of adhesive.
The reinforcing material 10 is thus provided with a total of four spiral patterns of adhesive, i.e., alternating patterns 138 and 142, which extend along substantially the entire width of the reinforc-ing material 10 as it passes beneath the adhesive .. . .
. : .: . . .:
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` ^~ -20- 2~2~401 applicator 74. As schematically illustrated in Fig.
2, thes~ spiral patterns 13~3 and 1~2 each comprise longitudinally extending overlapping loops of rela~
tively thin, elongated adhesive fibers 136 or 140 which cover only a portion of the total surface area of the reinforcing ma~erial 10. These thin, elongated adhesive fibers 136, 140 have a relatively low appli-cation temperature when they reach the reinforcing material 10, e.g., less than about 300F, which reduces the chance of wrinkling or warping of the reinforcing material 10 and completely eliminates the ~- 0 need for the ~ ! roller 78. In addition, a rela-~, tively small quantity of adhesive is required to form the adhesive patterns 138, 142 on the reinforcing material 10 but an acceptable bond is obtained between the polyethylene material 34 and the individual tape sections 12. Moreover, because of the substantial spaces or areas along the width of the reinforcing material 10 which are left uncovered by the thin loops of elongated adhesive fibers 136, 140, the knife roller 90 is protec~ed from rapid dulling and from substantial clogging with adhesive during the cutting operation of the individual tape sections 12.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted - ~
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`' ' ~0~1~01 for elements thereof without departing from the scope of this invention. In addition, many modifications may be ~ade to adapt a particular situation or mate-rial to the teachings of the invention without depart-ing from the essential scope thereof.
For example, while the disclosure of the method herein was primarily directed to the applica-tion of adhesive to the reinforcing material used to form reinforcing patches at the waist portion of disposable diapers or similar garments, it should be understood that the method of this invention is applicable to the formation of tape per se, and particularly tape formed from heat sensitive mate-rials.
Additionally, an adhesive applicator 74 of the type disclosed in the Boger Patent No. 4,815,660 is illustrated in the Figs. wherein side-by-side, counter-rotating spiral patterns of elongated adhesive fibers are applied to the reinforcing material 10. It is contemplated, however, that the adhesive dispensers 98a-d forming the applicator 74 could be adapted to apply spiral patterns of adhesive which rotate in the same direction and still obtain an acceptable coating of adhesive on the reinforcing material 10.
Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this ., .: ~ . .. .. , . , . . : . .
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~ ' ' ' , ' . ' ' ' ' ' ' ' ~ ' , , ' ' . , ' ~ ' ' .' ~ ' , ~,, . ' . . ~'' invention, but that the invention will lnclude all embodiments falling within the scope of the appended claims.
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backing sheet of such garments, however, tends to tear if the tape tabs are unfastened for any purpose. To solve this problem, a patch or section of reinforcing material has been secured to the outer surface of the polyethylene backing sheet at the front waist section of disposable garments for attachment to the tape tabs. This reinforcing material, e.g., polypropylene or a similar material, permits the tape tabs to be fastened and unfastened several times without render-ing the garment unserviceable.
Although it is desirable to provide asection of reinforcing material at the front waist portion of the disposable garment, diaper manufac-turers have been confronted with the problem of developing a method and apparatus for efficiently and economically attaching such reinforcing material to the garment. In some methods, for example, the -` 202~4~
patches or sections of reinforcing material are obtained from rolls wherein the reinforcing material is first coated with adhesive and then wound upon itself. During the garment manufacturing operation, these rolls are unwound and cut to si%e to form the patches or sections which are subsequently adhered to the appropriate location on the polyethylene backing sheet of the garment.
Wound rolls of reinforcing material have proven to be unsatisfactory for a number of reasons.
One problem is that the adjacent layers in the roll become adhesively bonded to one another and can be difficult to separate as the roll is unwound during the manufacturing process. If the adhesive attachment between the several layers of the roll is too strong, the polyethylene material may fracture or tear during unwinding. A lesser adhesive bond strength to reduce this problem can result in insufficient attachment of the reinforcing material when it is subsequently applied to the backing sheet. Strengthening of the reinforcing material itself to avoid tearing often results in excessive costs, or a finished garment having an unacceptable appearance.
Another attempt to avoid attachment between adjacent layers of a wound roll of reinforcing mate-rial involves the application of a non-stick release coating onto the adhesive. The problem with this 2~2~ 40~
approach, however, is that the release coating can reduce the adhesive bond strength to such an extent that the reinforcing material does not suitably adhere to the disposable garment. Alternatively, a separate layer of non-stick material has been interposed between adjacent layers of the wound roll of reinforc-ing material. This non-stick material avoids attach-ment between the layers of the roll, but adds to material costs and also requires an additional process step to remove the non-stick layer from the roll as it is unwound during the garment manufacturing operation.
In order to avoid the types of problems mentioned above with a wound roll of adhesive coated reinforcing material, methods have been proposed to apply the adhesive onto the reinforcing material in-line with the manufacture of the disposable gar-ment. U.S. Patent No. 4,795,510 to Wittrock et al, for example, discloses an in-line method for applying reinforcing material to the polyethylene backing sheet of a disposable garment in which the reinforcing material is unwound from an endless roll, adhesive is applied to the moving web or sheet of reinforcing material and then individual sections of adhesively coated reinforcing material are formed and attached at longitudinally spaced locations onto a moving sheet of the polyethylene material which forms the backing sheet of the disposable garment. In this method, a 2Q~
series of adhesive dispensers are mounted side-by-side to a carrier or support head immediately above the moving sheet of reinforcing material and are effective to apply a continuous coating of hot melt, thermo-plastic adhesive along the entire length and width ofthe moving sheet. These adhesive dispensers typically include slot nozzles which contact the moving rein-forcing material during operation to ensure that a uniform adhesive coating is applied across the entire transverse dimension of the moving reinforcing mate-rial.
Several problems are created with the application of hot melt adhesive to the reinforcing material in the manner disclosed in Patent No.
4,795,510. First, the application temperature of the continuous coating of hot melt adhesive is approxi-mately 300F which can cause the heat sensitive reinforcing material, i.e., polypropylene, to deform or wrinkle. As a result, chill rollers must be positioned immediately downstream from the adhesive dispensers to reduce the temperature of the hot melt adhesive before it damages the reinforcing material.
The addition of chill rollers to the manufacturing apparatus adds expense and complicates the adhesive application process.
Another problem with the method and appara-tus for applying adhesive to the reinforcing material --- ~ .. . .. . . . . . . . . .
2021 ~Bl disclosed in the 4,795,510 patent is that the slot nozzles employed by the adhesive dispensers must be placed in contact with the reinforcing material to obtain the desired pattern definition at the edges of the reinforcing material. This contact between the slot nozzles and reinforcing material creates wear on the slot nozzles requiring relatively frequent re-placement thereof. Additionally, mechanisms must be provided to raise and lower the adhesive dispensers with respect to the reinforcing material so that the dispensers can be lifted from the surface of the reinforcing material when the manufacturing process is interrupted or terminated for a period of time. Such mechanisms add additional cost to the system and complicate its operation.
Still another problem with the method of applying adhesive described above is that a relatively large quantity of pressure sensitive, hot melt thermo-plastic adhesive is required to provide a continuous coating across the entire length and width of the sheet of reinforcing material. Moreover, this pres-sure-sensitive, hot melt adhesive is highly viscous and "gummy". It has been found that difficulties are encountered when the sheet of reinforcing material having an uninterrup~ed continuous coating of adhesive is cut into separate sections or patches for applica-tion to the polyethylene backing sheet of a disposable ~ -7- ~2~9~
garment because the adhesive tends to dull and gum up the knife blades which cut such material. This creates maintenance problems and may require periodic stoppage of the manufacturing line to clean the adhesive from the knife blades. -~
Summary of the Invention It is therefore among the objectives of this invention to provide a method for applylng adhesive to tape material such as the reinforcing material applied to the waist portion of a disposable garment, which reduces the quantity of adhesive applied to the reinforcing material, which eliminates the need for ~`~
chill rollers, which reduces dulling and clogging of the knife blades used to cut the reinforcing material, `
which eliminates mechanisms for moving adhesive dispensers with respect to the reinforcing material and which increases the efficiency of the manufactur-ing operation while reducing costs. .
These objectives are accomplished in the method of this invention wherein a series of adhesive dispensers are mounted side-by-side immediately above a moving sheet or web of tape material such as the reinforcing material attached to the front waist portion of disposable garments. Each adhesive dis-penser is effective to extrude a relatively thick bead of adhesive toward the tape or reinforcing material and to impact the outer periphery of such extruded - ':
~- ~
-~- 2~2140 beaas wlth jets of air. ~he -drr ~ets are eff~ctive t attenuate or stretch such adhesive beads to form a relatively thin, elongated adhesive fiber, and to impart a twisting or rotational motion to such elon-gated fibers. In the presently preferred embodiment, the air jets of adjacent adhesive dispensers are oriented with respect to the path of the extruded adhesive beads such that the elongated adhesive fiber .,, .,. ~ ~
produced by one adhesive dispenser rotates in a clockwise direction and the elongated adhesive fiber produced by an adjacent adhesive dispenser rotates in a counterclockwise direction. These counter-rotating adhesive fibers from adjacent dispensers are deposited in side-by-side spiral patterns across the entire width of the reinforcing material as it moves longi-tudinally beneath the dispensers.
A number of advantages are obtained with the method of applying adhesive of this invention compared to prior art techniques of applying adhesive to heat sensitive tape or reinforcement such as disclosed in Patent No. 4,795,510. The elongated adhesive fiber produced by each adhesive dispenser herein is rela-tively thin compared to extruded adhesive beads and tends to retain much less specific heat upon applica-tion onto a substrate. As a result, the applicationtemperature of the elongated adhesive fibers upon impact with the tape or reinforcing material is 4~
g sufficiently low to avoid or reduce heat damage, i.e., wrinkling or buckling, to the heat sensitive tape or reinforcing material. In the manufacture of dispos-able garments, for e~ample, this reduction in applica-tlon temperature of the hot melt adhesive has resulted in the elimination of chill rollers downstream from the adhesive applicators.
Another advantage of the method of this invention is a reduction in the quantity of adhesive which is required to obtain an acceptable bond between the reinforcing material and polyethylene backing sheet of a disposable garment. The spiral pattern of adhesive obtained from each adhesive dispenser com-prises a series of loops or spirals which overlap one another in the longitudinal direction. Instead of a continuous coating of adhesive across the entire width and length of the tape or reinforcing material, the adhesive dispensers of this invention apply overlap-ping loops or spirals of a thin, elongated adhesive fiber to such material. This substantially reduces the amount of adhesive utilized, while providing sufficient bond strength between the reinforcing material and the backing sheet of a disposable garment or an~ other substrate.
The reduction in the quantity of adhesive applied to the tape or reinforcing material obtained by this invention also produces benefits when the -10- 2~
material is subsequently cut. A lesser quantity of adhesive on the tape or reinforcing material reduces the wear or damage to the knife blades which cut such material, and also lessens the problem of clogging of the ~nife blades with adhesive as the cutting opera-tion is performed. The expense of replacing or repairing worn knife blades is reduced, and the maintenance time associated with cleaning the blades during a manufacturing operation is also reduced.
A further advantage of this invention is that the adhesive dispensers are mounted in a fixed position above the moving tape or reinforcing mate-rial. Because there is no contact between the nozzle portion of the adhesive dispensers herein and the tape or reinforcing material, problems of wear and other contact damage with the slot nozzles employed in other methods have been eliminated. Moreover, no mechanisms are required to extend or retract the adhesive dis-pensers relative to the reinforcing material in the method of this invention because they are fixedly mounted in position and can remain in place when movement of the reinforcing material is stopped.
Description of the Drawinqs The structure, operation and advantages of the presently preferred embodiment of this invention will become further apparent upon consideration of the .: ~ : ~ : . . :: , .
::,: . .: . ~ : . , . ' ' Q~ 401 following description, taken in conjunction with the accompanying drawings, wherein~
Fig. 1 is a schematic perspective view of a disposable garment having a section of tape or rein-forcing material attached at the front waist portionthereof;
Fig. 2 is a schematic perspective view of an apparatus for adhering strips of reinforcing material to the polyethylene backing sheet of a disposable garment; and Fig. 3 is an enlarged front elevational view in partial cross section of the adhesive dispensing device adapted for use with the apparatus of Fig. 2.
Detailed Description of the Invention .
Referring now to the Figs., a method and apparatus is depicted for applying pressure sensitive, hot melt thermoplastic adhesive onto an endless length or web of tape material. In the illustrated embodi~
ment, the method is particularly adapted for the application of adhesive onto the reinforcing material 10 which is used in the formation of a reinforcing section 12 in a disposable diaper 14. It should be understood, however, that the method of this invention is applicable to the formation of tape material per se.
As shown in Fig. 1, the disposable diaper 14 comprises a moisture-impervious backing sheet 16 and a ,, ~, , .
.. ., :: ~ . . ~- . . .
~ 12- 2021401 body contactinq liner or layer 18 having a non-woven core or pad (not shown) therebetween. The diaper 14 is formed with a front waist section 20, a rear waist section 22 which mounts opposed tape tabs 24, 26 and elasticized leg openings 28 and 30 on either side of the centerline of the diaper 14. In this application, the method herein is directed to applying pressure sensitive, hot melt thermoplastic adhesive to one side of the tape section 12 which is adhered to the front waist section 20 of the diaper 14. The tape section 12 permits the tape tabs 24, 26 of the rear waist section 22 to be attached and reattached thereto as the diaper 14 is secured to the wearer without damage to the backing sheet 16 or any other part of the diaper 14.
Referring now to Fig. 2, a schematic view is illustrated of one form of an apparatus 32 for apply-ing adhesive to one side of an endless length or web : .: :
of reinforcing material 10 and for cutting such mate-rial 10 into individual tape sections or patches 12 which are then attached to a polyethylene material 34 used to form the backing sheet 16 of the disposable diaper 14. Many of the structural details of the apparatus 32 form no part of this invention per se and are discussed only briefly herein. Reference should be made to U.S. Patent No. 4,795,510 to Wittrock et al for a detailed explanation of the operation of ~ " . ~ . . . : . .
-13- 2~21~Q~
apparatus 32. For purposes of the presen~ discussion, the apparatus 32 comprises structure for withdrawing the polyethylene material 34 from a roll 35 and feeding it past an attachment station 36 where indi-vidual tape sections 12 are adhered thereto at longi-tudinally spaced locations therealong. The poly-ethylene material 34 is fed through a pair of guide rollers 40, 42, over a dancer roller 44 and then around a third guide roller 46 to a pair of counter-rotating nip rollers 48, 50 located immediatelyupstream from the attachment station 36. The poly-ethylene material 34 passes through the attachment station 36 where the individual tape sections 12 are adhered thereto, as discussed below, and then con~
tinues to a second pair of counter-rotating nip rollers 52, 54 which feed the material 34 to another station (not shown) for further processing.
Referring now to the top portion of Fig. 2, the reinforcing material 10 is fed over a first guide roller 60, between a pair of nip rollers 62, 64, and over spaced guide rollers 66 and 68 to an idler roller 70 carried by a support frame 72. The reinforcing material 10 is directed from the idler roller 70 between guide rollers 71, 73, ovér an idler roller 75 and tc a position beneath an adhesive applicator 74 discussed in detail below. This adhesive applicator 74 is effective to apply a number of side-by-side, - -14- 20214~1 longitudinally extending spiral patterns 138, 142 of adhesive onto the reinforcing material 10. After moving from the adhesive applicator 74, the reinf~rc-ing material 10 passes over a guide roller 78.
The reinforcing material 10 moves from the guide roller 78 over feed roller 80 to a turn bar 82.
The turn bar 82 directs the reinforcing material 10 to the attachment station 36 which comprises feed rollers 84, 86, a tension roller 88, a knife roll 90, a vacuum anvil roll 92, and a stomper roll 94. The reinforcing material 10 is directed by the feed rollers 84, 86 to the knife roll 90 which is effective to cut the reinforcing material 10 in a direction transverse to the path of movement of such material 10 thus forming individual tape sections or patches 12 which are held on the vacuum anvil roll 92 by the application of vacuum. These individual tape sections 12 are brought into a position beneath the moving polyethylene material 34 in alignment with the stomper 94 by rotation of the vacuum anvil roll 92. The stomper 94 is effective to press the polyethylene material 34 against the vacuum anvil roll 92 and the tape sections 12 it supports so each of the tape sections 12 is adhered to the bottom surface of the polyethylene material 34. As shown in Fig. 2, the tape sections 12 are longitudinally spaced along the polyethylene ~ . . . . .. . . . .. .
.. ~. . ~. , , i: :: : :
-15~ 4 ~ ~
material 34 in areas which form the front waist section of the finished disposable diaper 14.
Referring now to Figs. 2 and 3, the adhesive applicator 74 of this invention is illustrated in detail. In the presently preferred embodiment, this adhesive applicator 74 is of the type disclosed in U.S. Patent No. 4,815,660 to Boger, owned by the assignee of this invention, which is incorporated by reference in its entirety herein. The adhesive applicator 74 includes a manifold or carrier head 96 which mounts four adhesive dispensers s8a-d in side-by-side relation. While four adhesive dispensers 98a-d are illustrated in the Figs., it is contemplated that essentially any number of dispensers could be utilized depending upon the width of the reinforcing material 10 to be coated with adhesive.
The structure and operation of alternating adhesive dispensers 98a, c and g8b, d, respectively, are identical to one another. For purposes of the present discussion, only dispenser 98c is illustrated in detail and the operation of alternating dispensers is briefly described. Reference should be made to Patent No. 4,815,660 for a detailed discussion of same.
The adhesive dispenser 98c, for example, mounts a nozzle 100 formed with an adhesive passageway 102 which communicates with a source of adhesive (not :: . ' : '. ' ', .' '' .: ~ -.' -16- 202~01 shown) connected to the carrier head 96 The other end of adhesive passageway 102 terminates at an adhesive discharge opening 104. An air delivery passageway 106 is formed in nozzle 100 which is connected to an annular chamber 108 at the base of the nozzle 100. The air delivery passageway 106 is supplied with pressurized air from the carrier head 96 for purposes to become apparent below. Preferably, nozzle lO0 is formed with a reduced diameter portion having external threads which mate with internal threads formed in a cap 112. As described below, a first nozzle plate 114 is mounted by cap 112 to adhesive dispensers s8a and c, and a second nozzle plate 116 is mounted by cap 112 to the nozzle lO0 of adhesive dispensers 98b and d.
Each nozzle plate 114, 116 is formed with a throughbore 118, as shown with reference to dispenser 98c, having an inlet end connected to the adhesive passageway 102 of nozzle 100 and a discharge outlet 120. A number of air jet bores 122 are formed in nozzle plate 114, and a li~e number of air jet bores 123 are formed in nozzle plate 116. The air jet bores 122 and 123 of nozzle plates 114 and 116, respec-tively, are each connected to the annular chamber 108 of air delivery passageway 106 in nozzles 100 and have discharge outlets which are angled with respect to the longitudinal axis of the throughbore 118. The nozzle plates 114, 116 are each carried on an annular seat 128 formed in the caps 112. The caps 112 are threaded onto the lowermost end of the nozzles 100 so that the throughbore 118 of each nozzle plate 114, 116 communl~
cates with the discharge opening 104 of adhesive passageway 102, and the inlets of the air jet bores 122 and 123 communicate with the annular chamber 108 of air delivery passageway 106.
The operation of the adhesive applicator 74 is as follows. Heated hot melt thermoplastic adhesive is introduced into the adhesive passageway 102 of each nozzle 100 from the carrier head 96. An air-operated plunger 130, the lowermost end of which is illustrated in dispenser 98c of Fig. 3, is operative to permit the passage of the adhesive from the nozzle 100 into the throughbore 118 of each nozzle plate 114, 116. The hot melt adhesive is extruded through the discharge outlet 120 in nozzle plates 114 forming a first adhesive bead 132 ejected from dispensers 98a and c, and the hot melt adhesive extruded through the dis-charge outlet 120 in nozzle plates 116 forms a second adhesive bead 134 ejected from dispensers 98b and d.
At the same time the adhesive beads 132, 134 are extruded from the nozzle 100 of each dispenser 98a-d, pressurized air is directed through the air delivery passageway 106 and annular chamber 108 to the air jet :,, :
. : i -_ -18- 2 ~2 ~ 4 0~
bores 122 and 123 in the nozzle plates 114, 116, respectively.
As discussed in detail in U.S. Patent No.
4,815,660, the air jet bores ~22 of the nozzle plate 114 are angled relative to the longitudinal axis of the throughbore 118 therein so that the jets of air flowing through air jet bores 122 impact each first adhesive bead 132 substantially tangent to its outer periphery at a point below the discharge outlet 120 of the throughbore 118. The air ejected from the air jet bores 122 performs two functions. First, the air jets attenuate or stretch each first adhesive bead 132 to form an elongated adhesive strand or fiber 136 for deposition onto the reinforcing material 10.
Secondly, the air jets from the ~ores 122 impart a clockwise rotational or twisting motion to the elon-gated fibers 136, shown by the arrows in Fig. 3, so that the elongated fiber 136 from each dispenser 98a and c is deposited in a well defined, compact spiral pattern 138 onto the reinforcing material 10. See also Fig. 2.
The orientation of air jet bores 123 in the nozzle plates 116 of adhesive dispensers 98b and d is essentially the mirror image of that of the air jet bores 122 in the nozzle plate 114 of adhesive dispen-sers 98a and c. Jets of air from the air jet bores 123 impact the outer periphery of the second adhesive ~ . . ~, . . - ,-. . ,- ~ .. .. . . . . . .
'",' ~ :, . : ~ ' ~ : , " , . :.
~ ' , ~, ' ' !
` 19 bead 134 extruded from the nozzle plate 116 of each dispenser s8b and d to form elongated adhesive fibers 140 which are rotated in a counterclockwise direction, instead of the clockwise direction of rotation of the adhesive fibers 136. The adhesive dispenser 98b produces a spiral pattern 142 of the adhesive fiber 140 located between the two spiral patterns 138 of adhesive fibers 136 from adhesive dispensers 98a and b, and the adhesive dispenser g8b produces a spiral pattern 142 of adhesive fiber 140 located adjacent to the spiral pattern 138 of adhesive dispenser 98c. As discussed in detail in Patent No. ~,815,660, the counter-rotating adhesive fibers 136 and 140 which produce spiral patterns 138 and 142, respectively, contact one another at or near the top of the surface of the reinforcing material 10. Because adjacent adhesive fibers 136 and 140 are rotating in opposite directions, they do not interfere with one another upon contact with the reinforcing material 10 and produce little or no turbulence or eddies which can disrupt the pattern or produce uneven application of adhesive.
The reinforcing material 10 is thus provided with a total of four spiral patterns of adhesive, i.e., alternating patterns 138 and 142, which extend along substantially the entire width of the reinforc-ing material 10 as it passes beneath the adhesive .. . .
. : .: . . .:
.. .:: , . , . . :
` ^~ -20- 2~2~401 applicator 74. As schematically illustrated in Fig.
2, thes~ spiral patterns 13~3 and 1~2 each comprise longitudinally extending overlapping loops of rela~
tively thin, elongated adhesive fibers 136 or 140 which cover only a portion of the total surface area of the reinforcing ma~erial 10. These thin, elongated adhesive fibers 136, 140 have a relatively low appli-cation temperature when they reach the reinforcing material 10, e.g., less than about 300F, which reduces the chance of wrinkling or warping of the reinforcing material 10 and completely eliminates the ~- 0 need for the ~ ! roller 78. In addition, a rela-~, tively small quantity of adhesive is required to form the adhesive patterns 138, 142 on the reinforcing material 10 but an acceptable bond is obtained between the polyethylene material 34 and the individual tape sections 12. Moreover, because of the substantial spaces or areas along the width of the reinforcing material 10 which are left uncovered by the thin loops of elongated adhesive fibers 136, 140, the knife roller 90 is protec~ed from rapid dulling and from substantial clogging with adhesive during the cutting operation of the individual tape sections 12.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted - ~
.. . . .
`' ' ~0~1~01 for elements thereof without departing from the scope of this invention. In addition, many modifications may be ~ade to adapt a particular situation or mate-rial to the teachings of the invention without depart-ing from the essential scope thereof.
For example, while the disclosure of the method herein was primarily directed to the applica-tion of adhesive to the reinforcing material used to form reinforcing patches at the waist portion of disposable diapers or similar garments, it should be understood that the method of this invention is applicable to the formation of tape per se, and particularly tape formed from heat sensitive mate-rials.
Additionally, an adhesive applicator 74 of the type disclosed in the Boger Patent No. 4,815,660 is illustrated in the Figs. wherein side-by-side, counter-rotating spiral patterns of elongated adhesive fibers are applied to the reinforcing material 10. It is contemplated, however, that the adhesive dispensers 98a-d forming the applicator 74 could be adapted to apply spiral patterns of adhesive which rotate in the same direction and still obtain an acceptable coating of adhesive on the reinforcing material 10.
Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this ., .: ~ . .. .. , . , . . : . .
~ . .- ., ~ . ...
~ ' ' ' , ' . ' ' ' ' ' ' ' ~ ' , , ' ' . , ' ~ ' ' .' ~ ' , ~,, . ' . . ~'' invention, but that the invention will lnclude all embodiments falling within the scope of the appended claims.
.......
.- , :. .
! . , . ,'/ j~, : "'','.' "'"''' ;..~. .~
~ ' ' ' ~' ~`' '
Claims (13)
1. The method of forming tape, comprising:
moving a length of tape material relative to at least one adhesive dispenser;
extruding a bead of adhesive from said adhesive dispenser in a direction toward said tape material;
impacting the outer periphery of said adhesive bead with jets of air before said adhesive bead contacts said tape material to form an elongated adhesive fiber and to impart a twisting motion to said elongated adhesive fiber;
depositing said elongated adhesive fiber in a spiral pattern onto a surface of said tape material so that said surface is capable of adhering to a substrate.
moving a length of tape material relative to at least one adhesive dispenser;
extruding a bead of adhesive from said adhesive dispenser in a direction toward said tape material;
impacting the outer periphery of said adhesive bead with jets of air before said adhesive bead contacts said tape material to form an elongated adhesive fiber and to impart a twisting motion to said elongated adhesive fiber;
depositing said elongated adhesive fiber in a spiral pattern onto a surface of said tape material so that said surface is capable of adhering to a substrate.
2. The method of claim 1 in which said step of depositing said elongated adhesive fiber comprises depositing an elongated, pressure sensitive hot melt thermoplastic adhesive fiber onto a heat sensitive tape material at an application temperature which is sufficiently low to protect the heat sensitive tape material from buckling, warping and other heat damage.
3. The method of claim 1 in which said step of depositing said elongated adhesive fiber comprises depositing said elongated adhesive fiber in a spiral pattern of adhesive having a transverse dimension which is substantially equal to the transverse dimen-sion of said tape material.
4. The method of claim 1 in which said step of depositing said elongated adhesive fiber comprises depositing said elongated adhesive fiber in a spiral pattern consisting of longitudinally extending, overlapping loops which form open areas with no adhesive along said surface of said tape material.
5. The method of forming tape, comprising:
moving a length of tape material relative to a first adhesive dispenser and a second adhesive dispenser which are mounted side-by-side above the path of said tape material;
extruding a first adhesive bead from said first adhesive dispenser in a direction toward said tape material, and extruding a second adhesive bead from said second adhesive dispenser in a direction toward said tape material;
impacting the outer periphery of said first adhesive bead with jets of air before said first adhesive bead contacts said tape material to form a first elongated adhesive fiber and to impart a clock-wise twisting motion to said first elongated adhesive fiber, and impacting the outer periphery of said second adhesive bead with jets of air before said second adhesive bead contacts said tape material to form a second elongated adhesive fiber and to impart a counterclockwise twisting motion to said second elongated adhesive fiber so that said first and second adhesive fibers are counter-rotating;
depositing said first and second counter-rotating adhesive fibers in first and second, side-by-side spiral patterns onto a surface of said tape material so that said surface is capable of adhering to a substrate.
moving a length of tape material relative to a first adhesive dispenser and a second adhesive dispenser which are mounted side-by-side above the path of said tape material;
extruding a first adhesive bead from said first adhesive dispenser in a direction toward said tape material, and extruding a second adhesive bead from said second adhesive dispenser in a direction toward said tape material;
impacting the outer periphery of said first adhesive bead with jets of air before said first adhesive bead contacts said tape material to form a first elongated adhesive fiber and to impart a clock-wise twisting motion to said first elongated adhesive fiber, and impacting the outer periphery of said second adhesive bead with jets of air before said second adhesive bead contacts said tape material to form a second elongated adhesive fiber and to impart a counterclockwise twisting motion to said second elongated adhesive fiber so that said first and second adhesive fibers are counter-rotating;
depositing said first and second counter-rotating adhesive fibers in first and second, side-by-side spiral patterns onto a surface of said tape material so that said surface is capable of adhering to a substrate.
6. The method of claim 5 in which said step of depositing said first and second counter-rotating adhesive fibers comprises depositing said counter-rotating adhesive fibers in side-by-side spiral patterns so that the combined transverse dimension of said first spiral pattern and said second spiral pattern is substantially equal to the transverse dimension of said tape material.
7. The method of claim 5 in which said step of depositing said first and second counter-rotating adhesive fibers comprises depositing said first and second counter-rotating adhesive fibers in spiral patterns each consisting of overlapping loops extend-ing longitudinally along said tape material, said overlapping loops of adhesive forming areas with no adhesive on said surface of said tape material.
8. The method of claim 5 in which said step of depositing said first and second counter-rotating adhesive fibers comprises depositing said adhesive fibers at an application temperature which is suffi-ciently low to protect said heat sensitive tape material from buckling, warping or other heat damage.
9. The method of attaching a heat sensitive, tape material onto the plastic backing sheet of a disposable garment, comprising:
moving a length of heat sensitive tape material relative to a first adhesive dispenser and a second adhesive dispenser which are mounted side-by-side above the path of said tape material;
extruding a first adhesive bead from said first adhesive dispenser in a direction toward said heat sensitive tape material, and extruding a second adhesive bead from said second adhesive dispenser in a direction toward said heat sensitive tape material;
impacting the outer periphery of said first adhesive bead with jets of air before said first adhesive bead contacts said heat sensitive tape material to form a first elongated adhesive fiber and to impart a twisting motion to said first elongated adhesive fiber, and impacting the outer periphery of said second adhesive bead with jets of air before said second adhesive bead contacts said heat sensitive tape material to form a second elongated adhesive fiber and to impart a twisting motion to said second elongated adhesive fiber;
depositing said first and second adhesive fibers in first and second, side-by-side spiral patterns onto a surface of said heat sensitive tape material;
cutting individual sections from said length of said heat sensitive tape material and attaching said individual sections at longitudinally spaced locations along the plastic backing sheet of said disposable garment.
moving a length of heat sensitive tape material relative to a first adhesive dispenser and a second adhesive dispenser which are mounted side-by-side above the path of said tape material;
extruding a first adhesive bead from said first adhesive dispenser in a direction toward said heat sensitive tape material, and extruding a second adhesive bead from said second adhesive dispenser in a direction toward said heat sensitive tape material;
impacting the outer periphery of said first adhesive bead with jets of air before said first adhesive bead contacts said heat sensitive tape material to form a first elongated adhesive fiber and to impart a twisting motion to said first elongated adhesive fiber, and impacting the outer periphery of said second adhesive bead with jets of air before said second adhesive bead contacts said heat sensitive tape material to form a second elongated adhesive fiber and to impart a twisting motion to said second elongated adhesive fiber;
depositing said first and second adhesive fibers in first and second, side-by-side spiral patterns onto a surface of said heat sensitive tape material;
cutting individual sections from said length of said heat sensitive tape material and attaching said individual sections at longitudinally spaced locations along the plastic backing sheet of said disposable garment.
10. The method of claim 9 in which said step of impacting the outer periphery of said first and second adhesive beads comprises impacting the outer periphery of said first adhesive bead with jets of air to form a first elongated adhesive fiber and to impart a clock-wise twisting motion to said first elongated adhesive fiber, and impacting the outer periphery of said second adhesive bead with jets of air to form a second elongated adhesive fiber and to impart a counterclock-wise twisting motion to said second elongated adhesive fiber so that said first and second elongated adhesive fibers are counter-rotating.
11. The method of claim 10 in which said step of depositing said first and second counter-rotating adhesive fibers comprises depositing said first and second counter-rotating adhesive fibers in spiral patterns each consisting of overlapping loops extend-ing longitudinally along said tape material, said overlapping loops of adhesive forming open areas with no adhesive on the surface of said tape material.
12. The method of claim 10 in which said step of depositing said first and second counter-rotating adhesive fibers comprises depositing said adhesive fibers at an application temperature which is suffi-ciently low to protect said heat sensitive tape material from buckling, warping or other heat damage.
13. The method of claim 10 in which said step of depositing said first and second counter-rotating adhesive fibers comprises depositing said first and second counter-rotating adhesive fibers onto said surface of said heat sensitive tape material so that the combined transverse dimension of said first and second, side-by-side spiral patterns is substantially equal to the transverse dimension of said surface of said heat sensitive tape material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US41267289A | 1989-09-26 | 1989-09-26 | |
| US412,672 | 1989-09-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2021401A1 true CA2021401A1 (en) | 1991-03-27 |
Family
ID=23633949
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2021401 Abandoned CA2021401A1 (en) | 1989-09-26 | 1990-07-18 | Method for applying adhesive to the waist reinforcing material of disposable garments |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2021401A1 (en) |
-
1990
- 1990-07-18 CA CA 2021401 patent/CA2021401A1/en not_active Abandoned
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