"APPARATUS AND METHOD OF MANUFACTURING A TAPE FOR

DISPOSABLE DIAPERS"

Field of the Invention The present invention relates to an apparatus and method for manufacturing a tape suitable for use as a fastening means for a disposable diaper.

Background to the Invention

Disposable infant diapers, also known as baby nappies, are sold and used in vast quantities in Australia and other developed and developing countries, the latter being a market of high demand. A great deal of research and effort has gone into the design of disposable diapers to ensure that they are easy to use and that they effectively contain waste body fluids and other excreta. However the design of the fastening system for disposable diapers has not improved significantly over the last 30 years. Prior art fastening systems typically consist of matching tabs of hook and loop fastener material (such as that sold under the registered trade mark "VELCRO") which are provided at the respective four corners of the diaper.

However although the prior art fastening systems provide a tight and secure fit, they are relatively inflexible and often provide little room for movement and growth of a child. Comfort is an important factor in early childhood, both emotionally and physically. A diaper is usually the first garment that is worn by a new born baby, after it leaves the comfort and security of its mother's womb, and it is therefore desirable to make the garment as comfortable as possible. There is also increasing concern about the environmental impact of disposable diapers, which consume a disproportionately high volume of landfill each year. It is estimated that in Australia alone conventional disposable diapers fill up 114,000 cubic meters of land fill annually. Therefore it is highly desirable to make disposable diapers of bio-degradable materials in order to reduce the environmental impact. However prior art fastening systems of the hook and loop fastener type are typically made from non-

biodegradable plastics materials which persist for a long time in the environment.

The present invention was developed with a view to providing an apparatus and method for manufacturing a tape that may be used as a more comfortable fastening means for a disposable diaper and that is less susceptible to at least some of the disadvantages of the prior art. It will be appreciated that the tape may also be used for other purposes.

References to prior art in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere.

Summary of the Invention

According to one aspect of the present invention there is provided an apparatus for manufacturing a tape suitable for use as a fastening means for a disposable diaper, the apparatus comprising: a first web dispensing means for dispensing a continuous web of flexible fabric material; a second web dispensing means for dispensing a continuous web of flexible cover material; an adhesive dispensing means for dispensing a substantially continuous flow of an adhesive substance onto either one of said web of flexible cover material or said web of flexible fabric material; a web conveying means for continuously conveying said web of flexible fabric material through the apparatus; a web rolling means provided downstream of said adhesive dispensing means for rolling said web of cover material onto said web of fabric material with the adhesive substance there between; and,

a web collecting means for collecting said web of fabric material with the adhesive and web of cover material attached, wherein the finished product is ready for cutting into strips to form said tape for use as a fastening means. Preferably the first web dispensing means comprises a plurality of rolls, each roll having a separate web of fabric material wound thereon. Preferably a first roll and a second roll is provided, each roll having a continuous web of laminated non-woven fabric material respectively wound thereon. Preferably both webs are made from a biodegradable, polymer-based, laminated, non- woven, fabric material.

Preferably the second web dispensing means comprises a plurality of rolls, each roll having a separate web of cover material wound thereon. Preferably four rolls are provided, a first roll, a second roll, a third roll, and a fourth roll, each roll having its own web of cover material respectively wound thereon. Preferably the cover material is a release paper suitable for covering an adhesive substance. Preferably the adhesive substance is applied to one side of each of the webs of cover material. Typically the adhesive substance is applied to the webs of release paper by a pair of glue dispensers aligned with the first and second rolls and with the third and fourth rolls respectively. Advantageously the apparatus further comprises a web folding means in a first stage of the apparatus for producing an inner fold in each web of non- woven fabric material respectively. The inner fold is preferably produced substantially in the middle of each web so that it is folded back double onto itself. Preferably the apparatus further comprises an embossing device provided in a second stage of the apparatus. As the webs of fabric material pass through the embossing device they are pressed between a first pair of press rollers that emboss a predetermined pattern into the fabric material of the webs. Preferably said second stage of the apparatus also comprises a debulking and dotting device. When the embossed webs pass through the debulking and dotting device the fabric material is preferably debulked and dotted between a second pair of heated press rollers.

Preferably said web rolling means comprises a pair of rollers between which the webs of cover material and webs of fabric material pass and are rolled together with the adhesive substance in between. The apparatus preferably further comprises a web compressing unit in which the webs of fabric material with the adhesive substance and webs of cover material attached are firmly pressed together between a plurality of press rollers.

Preferably the web collecting means comprises a pair of rolls rotatably mounted on a single roll shaft onto which the two composite webs are wound ready for cutting into strips to form the tape for use as a fastening means in a disposable diaper.

According to another aspect of the present invention there is provided a method of manufacturing a tape suitable for use as a fastening means for a disposable diaper, the method comprising the steps of: dispensing a continuous web of flexible fabric material; dispensing a continuous web of flexible cover material; dispensing a substantially continuous flow of an adhesive substance onto either one of said web of flexible cover material or said web of flexible fabric material; conveying said web of flexible fabric material through each stage of the process; rolling said web of cover material onto said web of fabric material with the adhesive substance there between; and, collecting said web of fabric material with the adhesive and web of cover material attached, wherein the finished product is ready for cutting into strips to form said tape for use as a fastening means.

Preferably said step of dispensing a continuous web of flexible fabric material comprises dispensing a plurality of webs of flexible fabric material from a plurality of rolls, each roll having a separate web of fabric material wound thereon. Preferably each roll has a continuous web of laminated non-woven

fabric material respectively wound thereon. Preferably the webs are made from a biodegradable, polymer-based, laminated, non-woven, fabric material.

Preferably said step of dispensing a continuous web of flexible cover material comprises dispensing a plurality of webs of flexible cover material from a plurality of rolls, each roll having a separate web of cover material wound thereon. Preferably the cover material is a release paper suitable for covering an adhesive substance. Preferably in said step of dispensing a substantially continuous flow of an adhesive substance, the adhesive substance is applied to one side of each of the webs of cover material.

Advantageously in a first stage, the method further comprises the step of producing an inner fold in each web of non-woven fabric material. The inner fold is preferably produced substantially in the middle of each web so that it is folded back double onto itself. Preferably in a second stage, the method further comprises the step of embossing the webs of fabric material. Preferably as the webs of fabric material pass through the second stage they are pressed between a first pair of press rollers that emboss a predetermined pattern into the fabric material of the webs. Preferably said second stage of the method also comprises the steps of debulking and dotting the webs of fabric material.

Preferably said step of rolling the webs of cover material onto the webs of fabric material with the adhesive substance there between occurs in a third stage of the method. Preferably in a fourth stage, the method further comprises a web compressing step in which the webs of cover material with the adhesive glue provided thereon are firmly pressed onto the respective webs of fabric material.

Preferably said step of collecting the web of fabric material comprises winding the composite webs of fabric material with the adhesive and webs of cover material attached onto a pair of rolls rotatably mounted on a single roll shaft onto which the two composite webs are wound ready for cutting into strips.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise the word "preferably" or variations such as "preferred", will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention.

Brief Description of the Drawings The nature of the invention will be better understood from the following detailed description of a preferred embodiment of the apparatus and method for manufacturing a tape, given by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic side elevation of a preferred embodiment of the tape manufacturing apparatus according to the present invention;

Figure 2 is a schematic plan view of the tape manufacturing apparatus of Figure 1 ; and,

Figure 3 is a plan view of an infant diaper showing a preferred embodiment of the tape used as a fastening means; and Figure 4 is a perspective view of an infant diaper showing the manner in which the tape is used to fasten the diaper around an infant's waist.

Detailed Description of Preferred Embodiments

A preferred embodiment of the apparatus 10 for manufacturing a tape, as illustrated in Figures 1 and 2, comprises a first web dispensing means 12 for dispensing a continuous web of flexible fabric material 13. Preferably the first web dispensing means comprises a plurality of rolls, each roll having a separate web of fabric material 13 wound thereon. In this embodiment a first roll 14 and a second roll 16 is provided, each roll having a continuous web of laminated non-woven fabric material 13a and 13b respectively wound thereon. Preferably both webs are made from a biodegradable, polymer-

based, laminated, non-woven, fabric material. Each of the rolls 14 and 16 is approximately 700mm in diameter when full, and each web of fabric material is about 450mm in width. The first and second rolls 14 and 16 are rotatably mounted in bearings supported on a steel support frame 18. When viewed in plan, as shown in Figure 2, the rolls 14 and 16 are arranged side by side.

The apparatus 10 further comprises a second web dispensing means 20 for dispensing a continuous web of flexible cover material 21. Preferably the second web dispensing means comprises a plurality of rolls, each roll having a separate web of cover material wound thereon. In this embodiment four rolls are provided, a first roll 22, a second roll 24, a third roll 26, and a fourth roll 28, each roll having its own web of release paper 21a, 21b, 21 c, and 21 d respectively wound thereon. Each of the rolls 22, 24, 26, and 28 is approximately 500mm in diameter when full, and each web of release paper is approximately 45mm in width. Each of the rolls 22, 24, 26, and 28 are rotatably mounted in bearings supported on the steel support frame 18. When viewed in plan, as shown in Figure 2, the rolls are staggered, with a first pair of rolls 22 and 24 arranged on one side of the apparatus 10 and a second pair of rolls 26 and 28 arranged on the other side of the apparatus 10. The apparatus 10 further comprises an adhesive dispensing means 30 for dispensing a substantially continuous flow of an adhesive substance onto either one of said webs of flexible cover material 21 or said webs of flexible fabric material 13. In this embodiment the adhesive substance is applied to one side of each of the webs of release paper 21a, 21b, 21c, and 21 d by a pair of glue dispensers 30a and 30b aligned with the first pair of rolls 22 and 24 and with the second pair of rolls 26 and 28 respectively, as can be seen most clearly in Figure 2. The webs of release paper 21a and 21 b from the first pair of rolls 22 and 24 pass over a first transport roller 32a and then travel downwards passed the first glue dispenser 30a. The webs of release paper 21c and 21 d from the second pair of rolls 26 and 28 pass over a second transport roller 32b and then travel downwards passed the second glue dispenser 30b.

The apparatus 10 typically further comprises a web conveying means for continuously conveying the webs of flexible fabric material and the webs of cover material through the apparatus. In this embodiment said web conveying means comprises a plurality of conveyor belts placed at strategic locations throughout the apparatus 10 for conveying the webs through each stage of the process. A first conveyer belt 34 conveys the webs of non-woven fabric material 13a and 13b through a first stage of the process. Both webs 13a and 13b pass over a plurality of transport rollers 36 until they reach the fist stage of the process. The transport rollers 36 typically include both rollers with a steel outer surface and rollers with a rubber outer surface.

Advantageously in the first stage of the process a web folding means 40 is provided for producing an inner fold in each web of non-woven fabric material 13a and 13b respectively. The inner fold is produced substantially in the middle of each web 13 so that it is folded back double onto itself. This has the advantage of increasing the strength of the web and also producing an edge (the folded edge) of the web which is clean and straight. The folded edge is preferably the outer edge of each folded web 13a and 13b as it is emerges from the web folding means 40 onto the first conveyer belt 34. As can be seen most clearly in Figure 2, the width (225mm) of each folded web 13a and 13b is now half of what it was before folding (450mm). The two folded webs 13a and 13b now together have a total width (450mm) approximately equal to the original width of each width alone.

The two folded webs of non-woven fabric material 13a and 13b are carried by the first conveyer belt 34 to a second stage of the process. In the second stage of the process the webs 13a and 13b are preferably subject to the steps embossing, debulking and dotting. As can be seen most clearly in Figure 1 , an embossing device 42 and a debulking and dotting device 44 are provided in the second stage of the apparatus 10. As the webs 13a and 13b pass through the embossing device 42 they are pressed between a first pair of press rollers that emboss a predetermined pattern into the fabric material of the webs. Then as the embossed webs pass through the debulking and dotting device 44 the fabric is debulked and dotted between a second pair of

heated press rollers. The two layers of non-woven fabric material in each web 13a and 13b are thus effectively heat-welded together into a unitary structure.

As the debulked and dotted webs 13a and 13b emerge from the second stage of the apparatus 10 they pass onto a second conveyer belt 46 which transports the webs through a third stage of the process. In this third stage of the process the webs of release paper 21 a, 21b, 21c, and 21 d are attached to the respective webs of non-woven fabric material 13a and 13b with the adhesive substance there between. A web rolling means 48 is provided downstream of the adhesive dispensing means 30 for rolling each web of cover material onto the web of fabric material with the adhesive substance there between. In this embodiment the web rolling means 48 comprises a pair of rollers at the upstream end of the second conveyer belt 46, between which the webs of release paper 21 and webs of non-woven fabric material 13 pass and are rolled together with the adhesive glue in between. A pair of third conveyer belts 50a and 50b transport the two pairs of webs of release paper 21a, 21b, and 21c, 21 d from the glue dispensers 30a and 30b respectively, to the rollers of the web rolling means 48.

Preferably the webs of fabric material 13a and 13b with the webs of release paper 21a, 21 b, 21c, and 21 d attached are conveyed by the second conveyer belt 46 to a fourth stage of the process. In this fourth stage the webs of release paper 21a, 21b, 21c, and 21 d with the adhesive glue provided thereon are firmly pressed onto the respective webs of fabric material 13a and 13b. For this purpose the apparatus 10 preferably further comprises a web compressing unit 52 in which the webs of fabric material 13 with the adhesive and webs of cover material 21 attached are firmly pressed together between a plurality of press rollers.

As the webs 13a and 13b emerge from the web compressing unit 52 they typically pass through a web guider 54 into a tension control unit 56. The tension control unit 56 comprises a plurality of rollers mounted in two parallel movable frames that are free to move towards and away from each to

maintain a constant tension on the webs 13a and 13b as they emerge from the final stage of the process.

Finally a web collecting means 60 for collecting the composite webs of fabric material 13a and 13b with the adhesive and webs of cover material 21a, 21 b,

21c, and 21 d attached is provided at the end of the process. In this embodiment the web collecting means comprises a pair of rolls 60a and 60b rotatably mounted on a single roll shaft onto which the two composite webs are wound ready for cutting into strips to form the tape for use as a fastening means in a disposable diaper.

It will be appreciated that the finished product is preferably a pair of composite webs of non-woven fabric material 13a and 13b, each having a pair of webs of release paper 21a, 21 b and 21c, 21 d attached adjacent to each other along the outer edge thereof, with the adhesive glue therebetween. The two rolls 60a and 60b of composite web can then be placed directly into a diaper manufacturing machine (not shown) for dispensing the webs automatically into the machine. In the diaper manufacturing machine the webs 13a and 13b are cut into strips or tapes, typically between 1.5 cm to 3.0 cm in width, for attachment to the diapers as part of the fastening means. Each tape or strip of non-woven fabric material 13 will have two adhesive tabs at the outer ends covered by the release paper 21. The tapes or strips cut from the webs 13a and 13b form two halves of a single tape or strip suitable for use as a diaper fastening means. Preferably the two halves are joined together when they are attached to the diaper. Alternatively the two webs 13a and 13b may be welded together prior to cutting into strips or tapes.

Figures 4 and 5 illustrate a disposable infant diaper 70 to which a tape 72 manufactured in accordance with the preferred apparatus and method of the invention has been attached. As can be seen most clearly in Figure 3, the tape 72 has a pair of rectangular adhesive tabs 74 covered by a piece of the release paper 21 at each end. In use, the release paper is removed from at least one of the tabs 74 at each end of the tape 72 so that the adhesive

substance underneath is exposed, and can then be pressed against the front of the diaper, as shown in Figure 4, to secure the diaper to the infant's waist.

Now that a preferred embodiment of the apparatus and method for manufacturing a tape has been described in detail, it will be apparent that it provides a number of advantages over the prior art, including the following:

(i) It provides a manner of manufacturing composite webs of fabric material with an adhesive substance and cover material already attached that can be placed directly into a diaper manufacturing machine. (ii) It ensures that a light-weight, biodegradable, polymeric, non-woven, fabric material will have sufficient strength and other properties, including softness and flexibility, to make it suitable for use as a fastening means for disposable diapers.

(iii) As the apparatus and method can be fully automated it provides a manner of manufacturing the composite webs in large quantities rapidly and relatively inexpensively.

It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, in the described embodiment the composite web is produced in two halves, so that the finished product is a pair of composite webs. However it may be preferable in other circumstances to manufacture the composite web as a single unitary structure. In this case it is relatively easy to modify the apparatus and method by removing the folding stage and rolling the two original webs one on top of the other to produce a single double layer web of fabric material. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described and is to be determined from the appended claims.