Method, apparatus and article relating to a hook and loop fastening system

(54)

PATENT HOLDER SCA Mölnlycke AB, 405 03 Gothenburg SE

INVENTOR'S OFFICE NAME (56) (57)

Bengt Lindqvist, Mölndal SE, Roland Pfeifer, Bondues FR Albihns Patentbyrå Göteborg AB

Method, apparatus and product intended for Velcro fastening systems for disposable diapers

QUOTE PUBLICATIONS; - - SUMMARY: A method of maintaining a fastener tab (20) of a Velcro fastening system in a storage position on a product, such as disposable diaper (10). The fastening tab has a first end portion (122) permanently attached to the article and a second remote end portion (126) provided with projecting hook means (30). The distal end portion (126) is free from the article in a finished position of the mounting tab. The remote end portion, in the storage position, touches a surface of the article. The method comprises the steps of attaching the first end portion (122) of the fastening tab (20) to the article (10), and folding the distal end portion (126) of the fastening tab over the first end portion (122) of the tab so that the hook means (30) touch the surface of the the article. In order to increase contact between the hook means and the article, the hook means (30) of the second end part (126) of the fastening tab and the surface of the article are subjected to a relative displacement in a direction substantially parallel to the surface of the article. The invention further comprises an apparatus for carrying out the method, as well as a diaper.

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507 941

TECHNICAL FIELD:

The present invention relates to a method of maintaining a fastener of a Velcro fastening system in a storage position on a product, such as a disposable diaper, according to the preamble of claim 1. The invention further relates to an apparatus according to the preamble of claim 12 for carrying out the method. The invention also relates to a diaper according to the preamble to claims

18.

BACKGROUND OF THE INVENTION:

Various fastener systems have been used on low-cost or disposable items such as diapers, including pressure-sensitive, adhesive strips, buttons, and Velcro fasteners. Partly because of the sensitivity of the adhesive strips for soiling of e.g. talcum powder or children's oil, diapers provided with Velcro fastener systems now have an increasing market share.

Various types of Velcro fastener systems are known. In this regard, reference is made to EP-A-0 491 347, EP-A-0 324 578 and EP-A-0 276 970. These systems have in common that they are provided with a fastening tab usually attached to a first waist portion of the diaper, wherein the fastening tab is provided with an area of ​​hook material, and a receiving area usually on a second waist portion of the diaper, wherein the receiving area is provided with a plurality of loops to be hooked in by the hooks. The fastening tab is usually a flexible, oblong, rectangular strip of polymeric material, a first end thereof being attached to the diaper. The area with

507 941 for this purpose without the need for additional agents such as glue or extra loop material.

A further object is to provide an apparatus for carrying out the method according to the invention.

This object is achieved by the apparatus according to claim 12.

It is a further object of the invention to provide a diaper which exhibits improved properties in maintaining the storage position of its fasteners.

This object is achieved with a diaper according to claim 18.

Preferred embodiments of the method and apparatus are described in the respective subclaims.

BRIEF DESCRIPTION OF THE FIGURES:

The invention will now be described in more detail with various embodiments and with reference to the accompanying drawings, in which:

Fig. 1 is a schematic perspective view of a diaper provided with a first embodiment of a Velcro fastener system;

Fig. 2 is a schematic sectional view along line II-II i

Fig. 1;

Fig. 3 is a view similar to Fig. 2, but with the fastener in a storage position;

Fig. 4 is a schematic perspective view of a diaper provided with a second embodiment of a Velcro fastener system;

507 The 941 strength of the coupling is insufficient to guarantee that the tabs will maintain this storage position during the diaper journey along the production line. The tabs, due to their elasticity, can spring up and get stuck in the machinery of the production line, thereby possibly causing production stoppage and / or spillage due to the presence of defective products.

In the aforementioned EP-A-0 324 578 this problem is partially solved by providing a flap having a layer of pressure-sensitive adhesive along its central portion so that the central portion of the flap can adhere to the portion of the flap which is permanently attached to the flap. the diaper when the tab is in a storage position.

A further possible solution to this problem could be to provide the top layer of the diaper with a piece of loop material adjacent the first end of the tab, such that the distal end of the tab supporting the hooks can attach to the piece of loop material in the storage position. However, such a solution would entail higher costs due to the need to use extra loop material.

DISCLOSURE OF THE INVENTION:

It is therefore an object of the present invention to provide an alternative method for maintaining a fastening tab or part of a Velcro fastener system in a storage position, the method avoiding the disadvantages associated with other methods.

This object is achieved according to the present invention by the method of claim 1.

Since the method according to the claims ensures an improved adhesion between the surface of the product and the hook means, existing components of the diaper can be used for

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Fig. 13 is a schematic side view showing a production line comprising equipment for carrying out the method of the present invention;

Fig. 14 is a plan view of the equipment of Fig. 13;

Fig. 15 is a schematic cross-sectional view along line XV-XV of Fig. 13;

Fig. 16 is a schematic cross-sectional view along line XVIXVI of Fig. 13;

Fig. 17 is a schematic side view of an alternative apparatus for carrying out the method;

Fig. 18 is a cross-sectional view along line XVIII-XVIII of Fig. 17;

Fig. 19 is a schematic side view of an alternative apparatus for carrying out the method;

Fig. 20 is a schematic end view of the apparatus of Fig. 19;

Fig. 21 is a schematic side view of yet another alternative apparatus for carrying out the method; and

Fig. 22 is a schematic cross-sectional view along the line

XXII-XXII of Fig. 21.

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<td></td><td>Fig. 5</td><td>is a schematic sectional view along the line VV in Fig. 4;</td>

<td> 5</td><td>Fig. 6</td><td>is a view similar to Fig. 5, but with the fastener in a storage position;</td>

<td></td><td>Fig. 7</td><td>is a schematic block diagram showing a diaper manufacturing line comprising the method of the present invention;</td>

<td> 10</td><td colspan="2"></td>

<td></td><td>Fig. 8A</td><td>is a schematic end view showing equipment for carrying out the method of the present invention;</td>

<td> 15</td><td>Fig. 8B</td><td>is a schematic side view showing the equipment of Fig. 8A;</td>

<td> 20</td><td>Fig. 9</td><td>is a view similar to Fig. 8A but with a larger scale, showing how a diaper of Fig. 4 travels through the equipment of Figs. 8A and 8B;</td>

<td> 25</td><td>Fig. 10A</td><td>is a schematic end view of the second portion of a fastener before being subjected to the method of the present invention;</td>

<td></td><td>Fig. 10B</td><td>is a schematic end view of the second portion of a fastener while undergoing the method of the present invention;</td>

<td> 30</td><td colspan="2"></td>

<td></td><td>Fig. 11</td><td>is a schematic cross-sectional view of the fastener in its storage position;</td>

<td> 35</td><td>Figs. 12A</td><td>to 12J schematically illustrate various possible embodiments of rollers for use in the method of the present invention;</td>

507 941 each fastener 20 has a second surface or portion 26 from which a plurality of hook members 30 protrude. The hook means 30 are adapted to be coupled to a loop fastener member 32 located on the outer surface of the backing layer 12 of a second waist portion 34 of the diaper. When used, the second waist portion 34 of the diaper normally rests against the wearer's abdomen, while the first waist portion 24 extends over the wearer's back. If the outer surface of the backing layer is provided to allow the hook means 30 to snap into it with sufficient retaining force, it is, of course, not necessary to provide the diaper with additional loop fastener portions 32.

The hook means 30 may be made of any suitable material and be of any size, shape and distribution density which permits secure attachment of the fastening tabs to the loop fastener members 32. The hook means may, for example, be made of nylon material and have a hook or sponge shape . A suitable hook fastener is that which is sold by 3M ™ with the identification code CS200.

As shown in FIGS. 2 and 3, the first portion 22 of the fastener 20 is permanently disposed against the topsheet 14 of the diaper, for example by means of a suitable adhesive or welding.

The fastener 20 is shown in Fig. 3 in a storage position, that is, the position which is desirable to be taken as the diaper 10 travels along the production line and which position the fastener retains when the diaper is packaged. In the storage position, a portion of the topsheet 14, including the fastener 20, is bent over itself so that the hook means 30 protruding from the second portion 26 of the fastener touches the outer surface of the topsheet 14.

As soon as the hook means of the fastener come into contact with

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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS:

Although a method according to the present invention will be described below with reference to disposable diapers, it is understood that the method according to the claims can be applied to any article provided with a Velcro fastener system. The method is particularly suitable for use in disposable articles such as sanitary napkins with wings fitted with Velcro fasteners, adult incontinence garments and opening and resealable pant diapers.

A diaper is shown with the general reference numeral 10 in Figs. 1 to 3. The diaper 10 usually comprises a liquid impervious backsheet 12, a liquid impervious topsheet 14 and an absorbent core 16 therebetween. The diaper may also be provided with leg elastic 18 arranged along the side edges of the diaper. The materials of the constituent components of the diaper may be all normally used in this field. The backing layer 12, for example, may be a polyethylene film while the topsheet may be made of a material selected from a wide variety of materials such as natural fibers, synthetic fibers or a combination thereof. Importantly, the topsheet material contains fibers which can be hooked in by hooks belonging to a Velcro fastener system. One material which is well suited for this field of application is nonwoven spunbond polypropylene material, although the actual choice of material will depend on the type and shape of the hook means 20 used in the Velcro fastener system.

A first embodiment of a typical Velcro fastener system which can be used in the method of the present invention comprises a pair of polymer fasteners, generally designated by reference numeral 20, which have a first surface or portion 22 attached to a first waist portion of the diaper 10. As is most clearly shown in FIG. 2 have

507 941 denoted by reference numeral 20, in the form of flexible, elongated, rectangular, polymeric fastening tabs made of, for example, nonwoven materials. Each flap has a first portion in the form of a first end portion 122 attached to a first waist portion 24 of the diaper 10. As best shown in FIG. 5 For example, each flap 20 has a second portion in the form of a distal end portion 126 which extends beyond the edge of the diaper when the diaper is in a clear position, for example immediately before it is secured over a carrier. The distal end portion 126 of the tab carries a support 28 from which a plurality of hook members 30 protrude. As with the diaper of FIG. 1 For example, the hook means is provided to hook to a loop fastener portion 32 located on the outer surface of the backing layer 12 of a second waist portion 34 of the diaper. If the outer surface of the backing layer is provided to allow the hook means 30 to snap into it with sufficient retaining force, it is, of course, not necessary to provide the diaper with additional loop fastener portions 32.

The first end portion 122 of the tab 20 can, as shown in Figs. 5 and 6, are branched into a pair of snips 36 where one snap adheres to the outer surface of the backing layer 12 and the other snap adheres to the outer surface of the topsheet

14th Alternatively, the first end portion of the tab may be a unit and extend between the top layer and the back layer.

In Fig. 6, the fastening tab 20 is shown in a storage position, that is, the position which is desirable to be taken when the diaper 10 travels along the production line and which position retains the fastener when the diaper is packaged. In the storage position, the removed portion 126 of the tab is bent over the first end portion 122 so that the hook means 30 protruding from the support 28 of the fastener contacts the outer surface of the top layer 14. According to the present invention, when the hook means of the

507 941 the outer surface of the top layer 14, the hook means of the second part and the surface of the top layer are forced to perform a relative movement in a direction substantially parallel to the surface of the top layer, according to the present invention. Surprisingly, it has been found that, when these parts are subjected to a relative motion, a significant increase in retaining force is obtained between the hook means 30 and the outer surface of the top layer 14 compared to the retaining force obtained when this relative motion is not performed. In this regard, the term retaining force includes tear resistance and shear load resistance. A desirable value of the retaining force is a value which allows the fastener 20 to be retained in its storage position during the article's journey along the production line and during packaging of the article, but this value is not necessarily as high as the retaining force between hook and loop. components of a conventional Velcro fastener.

Without being bound by any specific theory or mechanical, it is likely that the relative movement of the hook members and the surface of the article in a direction substantially parallel to the surface of the article causes the hook members to wiggle between the fibers and the loops of the surface material and be retained thereon.

A second embodiment of a fastener system for use on an article will be described with reference to Figs. 4 to 6 before describing the apparatus, which is suitable for carrying out the method according to the invention. In these drawings, parts corresponding to equal parts in Figs. 1 to 3 denoted by the same reference numerals.

The Velcro fastener system of the second embodiment which can be used in the method of the present invention thus comprises a pair of fasteners, generally

507 941 box 38, wherein the topsheet and backsheet are attached together with the absorbent core disposed therebetween. Thereafter, the partially finished article proceeds to a second station 40 to which the fasteners are applied. With the fasteners in their storage position, as shown in Figs. 3 and 6, the partially finished article proceeds immediately to a third station 42 at which relative movement of the second portions of the fasteners and the top layer of the partially finished diaper occurs. Upon completion of the relative displacement, the diaper travels through a fourth station 44 at which subsequent completion operations are performed. Out of the fourth station 44 come complete and packaged diapers.

It will be apparent to those skilled in the art that the above-described sequence of steps may need to be varied depending on the constituents of the product. For example, it is conceivable that the topsheet 14 is provided with fasteners before being attached to the backsheet 12 and the absorbent core 16. In such a case, steps 40 and 42 will be performed prior to moving the article to station 38 at which lamination takes place.

Means for performing the relative displacement between the distal end portion of the tabs and the surface of the article to which the distal end portion touches are shown schematically in Figs. 8A and 8B. Accordingly, the third station 42 (Fig. 7) may be provided with a pair of mutually engaged rollers, a male roll 46 and a female roll 48, for each side of the article to which mounting tabs are mounted. For articles shown in Figs. 1 and 4, the production line will thus be equipped with two pairs of rollers. In the illustrated embodiment, the male roll 46 is provided with a circumferentially extending, projecting portion 50 which, with a play, extends into a circumferential groove on the female roll 48.

507 The 941 fastening tab has come into contact with the outer surface of the topsheet 14, the distal end portion 126 and the surface of the topsheet in a relative motion in a direction substantially parallel to the surface of the topsheet.

A further embodiment, not shown, allows the invention to be applied to an opening and resealable pant diaper. Such an article usually has a shape similar to the diaper shown in Figs. 1 to 4, with the exception that the loop fastener portion 32 forms part of the top layer of the other waist portion of the diaper. In other words, the loop fastener portion may be formed as patches attached to the corner regions of the other waist portion or the top layer may itself serve as such loop fastener portions. The storage position of such a pant diaper is taken when the fasteners on the first waist portion snap into the loop fastener portion or the portions of the second waist portion. This storage position then corresponds to the mode of use of the pant diaper until the pant diaper is opened by separating the first waist portion from the second waist portion.

Common to all embodiments of the invention is that in the intake storage position, the second portion 26, 126 is subjected to the fastener and surface of the article which touches the second portion to a relative movement in a direction substantially parallel to the surface of the article. In this regard, the expression surface of the article means any part of the article affected by the fastener in its storage position, including all loop fasteners.

An apparatus for carrying out the method of the present invention is shown in the remaining drawings. Fig. 7 schematically shows a production line for the manufacture of diapers. The boxes 12, 14 and 16 symbolize the backing layer, the topsheet and the absorbent core, respectively, where these components are fed to a first station symbolized by

507 941

F in the region of the surface of the topsheet 14 in directions substantially parallel to the surface as soon as the second portion leaves the third station and the diaper becomes substantially flat. These compressive forces help to increase the retaining force of the fastener in the storage position.

The actual size and shape of the rollers which are mutually engaged do not appear to be critical. Various conceivable shapes of the surfaces 50 and 52 which are mutually engaged are shown by way of example in Figs. 12A to 12J. It will be noted that in several of the embodiments shown, rubber 54 or similar flexible material may be placed in the groove 52 or along the protruding portion 50. The male and female rolls may preferably have a diameter between 20 and 200 mm, advantageously around 100 mm. The projecting portion 50 of the male roll 46 may preferably have a radius of about 6 mm.

A section a embodiment of the diaper manufacturing line at the third station 42 is schematically shown in Figs. 13 to 16 and comprises a pair of rollers which are mutually engaged 46, 48 located in a central portion of a guide groove 56 in a table 58 of the production line. The guide groove 56 begins upstream of the roll pair 46, 48 and gradually becomes wider and deeper until it reaches the vicinity of the roll pair, at which point the table 58 is provided with a through opening 60 within which the two rollers are mutually engaged. Downstream of the roll pair, the shape of the guide groove is a mirror image of the shape upstream. The guide groove 56 serves to guide the second portion of the fastening tab and the area of ​​the laminated area which is in contact with the hook means in an appropriately directed manner toward and through the roll pair 46, 48. The gradual taper of the portion of the guide groove 56 downstream serves to ensure that the fastener remains in its storage position after passing through the roll pair 46, 48.

507 941

The clearance between the protruding portion 50 and the groove 52 shown in Fig. 9 is large enough to allow the removed end portion 126 of the tab 20 and the laminated top layer 14 and the backing layer 12 of the diaper shown in Fig. 4 to pass therethrough. Relative displacement of the distal end portion 126 of the attachment tab 20 and the outer surface of the topsheet 14 is obtained because the hook means 30 are forced to change their positions relative to the loop material of the topsheet as the distal end portion 126 of the attachment tab 20 passes through the roll pair. The occurrence of relative displacement is clearly shown in a comparison of Figs. 10A and 10B.

In Fig. 10A, the second portion 26 of the fastener is shown in a state prior to being treated by the method of the present invention in which relative displacement is created. The second portion 26 is usually planar and the distal tips of a pair of adjacent hook means 30 disposed on the other portion are spaced a certain distance y. The distance between the tips of the same adjacent hook means 30 increases to a value z when subjected to the method of the present invention, as shown in Fig. 10B, while moving the second portion 26 relative to the surface of the article. As soon as the fastener is traversed through the station at which the relative movement is effected, the elasticity of the fastener will cause the tips of the hook members to lean toward each other. This condition is shown in more detail in Fig. 11.

Accordingly, Fig. 11 shows a fastener 20 in its storage position at which the hook means 30 hooks at fibers and / or loops of a region of the outer surface of the top layer 14. Since the second portion 26 of the fastener 20 in the third station 42 has been previously exposed for bending which created a radius r, the hook means 30 of the fastener will exert compressive forces denoted by

507 941

The above-described embodiment is particularly suitable for carrying out the method of the invention on fasteners which are relatively wide. This is because the second part of the fastener is forced to assume a position within the fold block 64 in which it covers almost the entire periphery of the belt 60. This can be compared to the male roller shown in Fig. 12 in which the second part of the fastener only covers a semicircle. .

An alternative apparatus for obtaining satisfactory relative displacement of the second portion of a relatively wide fastener and the surface of the article by means of rollers is shown in Figs. 19 to 22. In Figs. 19 and 20 are a pair of male rolls arranged close to one another along a common axis 72. The first of these rolls cooperates with a first female roll 48 upstream of the male rolls, while the second of the male roll pair cooperates with a second female roll 48 Downstream of the male rolls. As shown in Fig. 20, this arrangement guarantees that the relative displacement between the second portion of the fastener and the surface of the article to which it touches can be obtained even if the width of the other portion exceeds the width of the groove 52 of one of the female rollers 48.

In the apparatus shown in Figs. 21 and 22, two pairs of male and female rollers 46, 48 cooperate, one pair being positioned upstream relative to the other. As shown in Fig. 22, the roll pair is axially displaced relative to each other so that a width w is formed in which relative displacement of the fastener and the surface of the article is achieved, this width w being greater than the width of the groove 52 of each female roll 48.

The present invention is, of course, not limited to the embodiments described above and shown in the drawings, but may be varied within the scope of the appended claims. For example, the pair of rolls 46, 48 need not necessarily be arranged along the cn7 of the diaper ο Ή · ✓ / ✓ ΤΙ

It will be obvious to those skilled in the art that it is important for the method of the invention that only the second part of the fastener and the topsheet be made to change shape so as to cause the hook members to hook better in the topsheet material or any other surface of the article to which the fastener is intended to lock in its storage position. In this regard, it is obvious that the necessary relative movement of the parts traveling through the station 42 can be accomplished by a single roller, either male or female, which cooperates with a fixed member. It is also conceivable that a suitable relative displacement can be achieved without the aid of rollers by using an appropriately curved protruding plate over which the other portion of the fastener is forced to move, thereby causing the tips of at least some of the hook members to disintegrate.

A further embodiment of an apparatus suitable for performing the relative displacement of the second portion of the fastener and the material to which it touches is shown in Figs. 17 and 18 and comprises an endless belt 60 running in a channel 62 which is open upwardly arranged in a fold block 64 mounted on the production line table. The folding block 64 is provided with an inclined surface 66 upstream along which the second portion of the fastener and associated portions of the laminated material run before being drawn into the channel 62 by the belt 60. During travel through the channel 62, the second portion of the fastener and the laminated the material to perform a relative displacement so as to cause the hook members of the mounting tab to enter and snap into the surface material of the top layer. A contour sketch of the fastener and laminated material within channel 62 is indicated by reference numeral 68 in Fig. 18. The fold block 64 is provided with a sloping surface 70 downstream to ensure an unobstructed exit of the fastener and material from channel 62.

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106552 AH / UAW

1998-01-31