Patent Description:
Tampons are well known in the art and are used for feminine hygiene. Also many tampon manufacturing methods and apparatuses have been disclosed in the prior art. Generally, a distinction is made between folded and rolled tampons. The former have improved absorbent characteristics, but possess less strength and are commonly used with an applicator to reduce the chance of tears and other damage to the tampon before insertion. Rolled tampons are slightly less absorbent, but more sturdy and can be applied digitally, as opposed to the folded tampons. Furthermore, measures can be taken to increase the absorbency of the rolled tampons. The invention will focus on uses concerning rolled tampons and intermediate products thereof.

Rolled tampons comprise a rolled absorbent fiber sheet and a withdrawal string for removal. Rolled tampons are manufactured by rolling multiple-layered sheets. The multiple-layered sheets comprise a layer of absorbent material of a certain length, upon which a strip of web material is bonded which has only a fraction of the length of the layer of the absorbent material, thus creating the multiple-layered sheets. A further description of this product will be provided later in this document.

It is desired to attain a maximal production speed, but one recurring problem is that the machines are often subject to mechanical failure especially during the bonding of the thermoplastic film onto the absorbent material. For example <CIT> describes a process with ironing plates meant to heat up and melt a thermoplastic film onto the absorbent material. <CIT> also describes a process where a heating element is pressed against a wound tampon blank to seal the free-end of the strip onto the absorbent material. The melted thermoplastic film is thereby bonded with the absorbent material. The issue in these processes is that a portion of the melted film sticks onto the ironing plates creating a layer of molten film which decreases the heating yield in time thus resulting in a worst bonding of the film onto the absorbent material.

Document <CIT> describes a method for intermittently providing strips of a continuous first web material onto a continuous second web material for manufacturing tampon blanks however the efficiency of this method needs to be improved.

The invention thereto aims to provide a method and apparatus which ensures an efficient and reliable bonding of the film material onto the absorbent material.

The present invention provides a method for manufacturing a tampon, comprising the steps of:.

According to the invention, the sealing step comprises ultrasonic bonding, wherein the bonding step concurrently comprises an embossing step where the bonding station comprise an embossment roller that has spaced apart protrusions, the partially laminated structure being arranged in a way that the first web material comes into contact with the embossment roller.

The method according to the present invention allows an adequate melting of the second web material onto the first web material or vice versa. Indeed, vibrations can be induced at a distance, therefore it is possible to melt the second web material at a distance therefore suppressing any stagnant layer of molten web on the heating element. This results in an improved sealing of bonding of the film onto the absorbent material.

According to an embodiment, the sealing station comprises at least one sealing sonotrode inducing vibrations at a frequency between <NUM> and <NUM>, preferably between <NUM> and <NUM>.

According to an embodiment, the sealing station comprises three or five sealing sonotrodes inducing vibrations at a frequency between <NUM> and <NUM>, preferably between <NUM> and <NUM>.

According to an embodiment, the at least one sealing sonotrode is mounted mobile within an arcuate railing and is configured to move at an constant distance relative to the rotatable clamping means.

According to an embodiment, the at least one sealing sonotrode is mounted mobile within an at least partially linear rail and is configured to move closer or remoter to the rotatable clamping means.

According to an embodiment, the continuous second web material is supplied at a second speed, whereby said second speed is greater than zero, preferably whereby said second speed is constant; the continuous first web material is supplied at a first speed, which is higher than the second speed, preferably whereby said first speed is constant, the method comprising a step of accelerating the strips from the second speed to the first speed; wherein the step of accelerating the strips from the second speed to the first speed is conducted essentially concurrently with the step of bonding a first-end of the strip of second web material to the continuous first web material, thereby forming a partially laminated structure.

According to an embodiment, the method further comprises a step of applying predetermined breaking points on the continuous first web material, whereby the predetermined breaking points are applied transversally with respect to a longitudinal axis of the continuous first web material and equidistantly repeated over the longitudinal axis of the continuous first web material, and whereby said step of applying predetermined breaking points is executed prior to the bonding step.

The invention also pertains to an apparatus for manufacturing a tampon, comprising:.

According to the invention, the sealing station comprises an ultrasonic welding device inducing vibrations, wherein the bonding station comprises an embossment roller comprising a smooth surface and a embossed surface, the embossed surface comprising an embossment pattern with at least one row of protrusions, said protrusions being arranged in the same orientation for each row and being spaced apart from one another.

According to an embodiment, the ultrasonic welding device is at least one sealing sonotrode inducing vibrations at a frequency between <NUM> and <NUM>, preferably between <NUM> and <NUM>.

According to an embodiment, the apparatus further comprises a weakening station, said weakening station preferably comprising a weakening roller, more preferably a perforation roller, and a counterpressure roller, for applying predetermined breaking points on the first web material or on the partially laminated structure, whereby the predetermined breaking points are applied transversally with respect to a longitudinal axis of the continuous first web material and equidistantly repeated over the longitudinal axis of the continuous first web material.

According to an embodiment, the apparatus further comprise conveying means and preferably guiding means arranged between the bonding station and the winding station in order to convey the partially laminated structure from the bonding station to the winding station, said conveying means comprising at least two, preferably four rollers arranged two by two, the partially laminated structure passing through each pair or roller.

According to an embodiment, the sealing station comprises a reciprocating mechanism enabling the movement of the at least one sealing sonotrode closer or remoter to the rotatable clamping means.

According to an embodiment, the sealing station comprises a actuating mechanism enabling the movement of the sealing sonotrode at a constant length relative to the rotatable clamping means, i.e. the sealing sonotrode and the rotatable clamping means are separated by a gap that has a constant height.

According to an embodiment, the bonding station comprises an ultrasonic welding device to bond the first-end of the second web material to the first web material, the ultrasonic welding device comprising a bonding sonotrode inducing vibrations at a frequency between <NUM> and <NUM>, preferably between <NUM> and <NUM>.

All of these embodiments mentioned above can be taken individually or in combination.

Further embodiments are described below and in the claims.

The present invention concerns an improved method for producing a tampon, and an apparatus for doing so, as well as the product manufactured by said method.

"Comprise," "comprising," and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

The term "nonwoven web material" means a sheet material having a structure of individual fibers or threads which are interlaid, but not in a regular manner such as occurs with knitting or weaving processes. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, spunbonding processes, and bonded carded web processes.

The term "thermoplastic" is meant to describe a material that softens when exposed to heat and which substantially returns to its original condition when cooled to room temperature.

The term "rayon" refers to a manufactured regenerated cellulose fiber, made from purified cellulose. It has a smooth, soft surface, and is therefore very suitable to be used in a tampon.

The term "concurrently" or "essentially concurrently" refers to the simultaneous or overlapping occurrence or execution of two or more events or steps.

The term "speed", both the first speed as the second speed, refers to the speed at which the first or second web material moves. This can for instance be the tangential speed at the surface of conveying rollers (and/or possibly the separation roller and/or the weakening roller).

The term "first web material" can also refer to already cut strips of the continuous web material. This is to be noted as the cutting of the strips occurs very fast and sudden. The first web material may be continuous at the start of a process, such as being conveyed (or a first section of the first web material being conveyed), but can be cut during the process. As such, the term "first web material" covers both the continuous first web material as the strips of the first web material.

The term "predetermined breaking points" refers to areas of weakened tensile strength, which are applied along a line, in this case usually in a line transversal with respect to the longitudinal axis of the web material. This creates "breaking lines", which allows the web material to be separated more easily into strips or sections, for instance by tearing or cutting, while still allowing the web material to be conveyed at high speeds without tearing at inopportune times. These predetermined breaking points can be applied by several different processes, for instance by applying perforations through small cuts, or by weakening certain zones by scraping off some of the material, thus weakening it. In other cases the weakened zones can be achieved by applying heat and/or acid to reduce the tensile strength. Note that combinations of the aforementioned methods are also possible, as well as others which have not been mentioned but are considered to be common knowledge in the field.

<FIG> illustrates schematically from a side view a module, or a part, of the apparatus and process to manufacture tampons, in accordance with an embodiment of the present invention. Specifically, <FIG> shows namely the bonding of a first web material <NUM> with a second web material <NUM>. In <FIG>, a possible configuration is shown of an apparatus for manufacturing tampon blanks. However, it is to be noted that not all of these elements are strictly necessary and/or could be replaced by other elements with similar functions in order to accomplish the objective of the invention, and that the invention is therefore not limited to this embodiment.

In the apparatus, a first web material <NUM> is provided continuously at a first speed to a weakening station <NUM>,<NUM>. In this embodiment, the weakening station <NUM>,<NUM> comprises a weakening roller <NUM> and a counterpressure roller <NUM>. The weakening roller in this case is a perforation roller <NUM> and comprises one or more (two, three, four or more) blades that apply a perforation line on the first web material <NUM> and the counterpressure roller <NUM> acts as an anvil. The weakening station <NUM>,<NUM> can also scrape off material in zones of the first web material <NUM>, or treat the first web material <NUM> with acid or heat to create predetermined breaking points <NUM> (as seen in <FIG>), or even employ a combination of more than one of said methods. In the preferred embodiment, the weakening station <NUM>,<NUM> is a perforation station and the perforation roller <NUM> comprises blades to form a zigzag pattern along the perforation line. The distance between subsequent perforation lines can be adapted by using a different perforation roller <NUM> with a different number of blades and/or a different diameter and/or different rotational speeds. Note however that the weakening station <NUM>,<NUM>, or parts thereof, also acts as a conveying system for the first web material <NUM>. After being perforated, the first web material <NUM> is conveyed over the counterpressure roller <NUM> of the weakening station <NUM>,<NUM> to the bonding station <NUM> that will be described afterwards. As illustrated in <FIG>, the weakening roller <NUM> rotates counter-clockwise whereas the counterpressure roller <NUM> rotates in the opposite direction, i.e. clockwise.

The invention is not limited to this specific embodiment and the rollers can be arranged differently. For example, in <FIG> the weakening roller <NUM> is arranged vertically under the counterpressure roller <NUM>. This arrangement can be inverted where the counterpressure roller <NUM> can be arranged under the weakening roller <NUM>.

According to another embodiment, the first web material <NUM> may be conveyed toward the bonding station <NUM> without passing through a weakening station. There can only be one roller here the one reference as <NUM>, or two rollers <NUM>,<NUM> each comprising a smooth outer surface, and acting as pulling rollers conveying the first web <NUM> towards the bonding station <NUM>. A weakening station can be implemented downstream of the bonding station <NUM>.

In the apparatus, a second web material <NUM> is provided continuously at a second speed to a separation station <NUM>,<NUM> by a first conveying system <NUM>,<NUM>. The separation station <NUM>,<NUM> is illustrated in <FIG> which corresponds to a close-up of <FIG>. In this embodiment, the first conveying system <NUM>, comprises a pulling roller <NUM> for pulling/unwinding the second web material <NUM> from a web roll or other sources, and conveying it further along to the separation station. The first conveying system <NUM>,<NUM> can further comprise a guiding roller <NUM> for correctly guiding the second web material <NUM> to the pulling roller <NUM>. The guiding roller <NUM> possibly comprises a guiding notch for centering the second web material <NUM> in case of deviation of the path of the second web material <NUM> while being pulled from the web roll or other sources. Subsequently, the second web material <NUM> is conveyed through the separation station <NUM>,<NUM>, where a separation roller <NUM> cuts the second web material <NUM> into strips in concert with a counterpressure roller <NUM> acting as an anvil which conveys the second web material <NUM> and the cut strips and provides a base on which the second web material <NUM> can be cut by the separation roller <NUM>. The separation roller <NUM> in this example comprises two blades placed at opposite sides of the separation roller <NUM>, however other versions can be used, having one, three, four, five or more blades. Preferably, the separation roller <NUM> and the counterpressure roller <NUM> rotate at equal (or at least similar) tangential surface speeds in order to provide a clean cut without dragging the second web material <NUM>. In order to change the length of the strips cut by the separation roller <NUM>, a separation roller <NUM> with a different diameter and/or a different amount of blades and/or a different rotational speed can be used. When the second web material <NUM> has passed the separation station <NUM>,<NUM>, not necessarily as a cut strip yet, the second web material <NUM> is conveyed further by a combining roller <NUM> towards the bonding station <NUM>. The combining roller <NUM> is adapted to push the first web material <NUM> and the second web material <NUM> further along to the bonding station <NUM> where the strips of second web material <NUM> can be bonded onto the first web material <NUM>. The combining roller <NUM> corresponds to the point in the method and apparatus where the first web material <NUM> and the second web material <NUM> are combined but not bonded yet.

The invention is not limited to this specific embodiment and the rollers <NUM>,<NUM>,<NUM>,<NUM>,<NUM> can be arranged differently. For example, in <FIG> the second web material <NUM> passes under the guiding roller <NUM>, between the counterpressure roller <NUM> and the pulling roller <NUM>, and then between the counterpressure roller <NUM> and the separation roller <NUM>. This arrangement can be modified for example by taking out the guiding roller <NUM>, the pulling roller <NUM> acting as a pulling and guiding roller or by arranging the pulling roller <NUM> at a distance from the separation station <NUM>,<NUM>. As illustrated in <FIG>. , the guiding roller <NUM>, the pulling roller <NUM> and the separation roller <NUM> all rotate in the same direction, here clockwise, whereas the counterpressure roller <NUM> rotates in the opposite direction hence counter clockwise. Of course, each can be inverted as needed, for example the second web material <NUM> can be placed vertically under the guiding roller <NUM>, thus going over the guiding roller <NUM>, the guiding roller <NUM> would then rotate counter-clockwise.

The apparatus can further comprise an extension for example in the form of a ramp to collect the second web material <NUM> from the counterpressure roller <NUM>. Furthermore, air blowing means can be implemented to provide constant air streams to press the second web material <NUM> against said extension or against the first web material <NUM>, thus reducing the risk of the second web material <NUM> curling up.

The combined first web material <NUM> and second web material <NUM> are conveyed by the combining roller <NUM> towards the bonding station <NUM>. The bonding station <NUM> comprises an embossed roller <NUM> and a ultrasonic welding device <NUM> as illustrated in <FIG>. The ultrasonic welding device <NUM> comprises a vibration generator <NUM>, for example and not limited to, a magnetostrictive or piezoelectric transducer, said generator <NUM> is attached to a tapering rod or probe usually made out of metal, such as and not limited to titanium, aluminum or steel, that will be referenced herein as the bonding sonotrode <NUM>. The bonding sonotrode <NUM> is submitted to the vibrations generated by the generator <NUM> and said bonding sonotrode <NUM> then applies this vibrational energy to the combined first and second web material <NUM>,<NUM>. The vibrational energy causes the partial melting of the second web material <NUM> so as to bond the first and second web material <NUM>,<NUM> in these melting points.

The melting points, which can be considered as bonding regions <NUM> (see <FIG>), are defined by the embossment pattern 29a of the embossment roller <NUM>. The embossment roller <NUM> as illustrated on <FIG>, comprises at least one embossed surface <NUM> comprising an embossment pattern 29a and at least one smooth surface <NUM> lacking any embossment. Preferably, the embossment roller <NUM> comprises two identical embossment patterns 29a, or two embossed surface <NUM>, arranged on opposite sides of the roller <NUM>. The embossment pattern 29a corresponds to protrusions <NUM>, in other words protuberances protruding in a radial direction from the smooth surface of the embossment roller <NUM>, said protrusions <NUM> being spaced apart from one another.

The protrusions <NUM> correspond here to truncated elliptical cones that decrease in surface from the base, corresponding to the surface of the embossment roller <NUM>, up to its apex. As illustrated in <FIG>, each protrusion <NUM> is identical to the other and presents an oblong surface at its apex. Starting from the apex, each protrusion <NUM> widens in direction of the base. Each protrusion <NUM> presents at its apex an oblong surface with two opposite sides being larger than the two other opposite sides, in other words, the apex surface of each protrusion extends, or is elongated, sensibly in one direction of axis P as illustrated in <FIG>.

According to one embodiment, as illustrated in <FIG>, the protrusions <NUM> are arranged in rows. More precisely, the protrusions <NUM> are aligned in n rows, where n is natural number, or positive integer. In other words, the embossment pattern 29a can comprise <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> , <NUM>, <NUM>, <NUM> or more rows. As illustrated in <FIG>, the embossment pattern 29a comprises four rows 29rm. Each row 29rm comprises m protrusions <NUM>, where m is natural number, or positive integer. In other words, each row 29rm can comprise <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> , <NUM>, <NUM>, <NUM> or more protrusions <NUM>. As illustrated in <FIG>, the embossment pattern 29a comprises four rows 29rm, two rows comprise eight protrusions <NUM> and two rows comprise seven protrusions <NUM>.

The invention is not limited to this specific embodiment, the embossment pattern 29a can comprise five rows 29rm of protrusions <NUM> as illustrated in <FIG>, and the rows of protrusions <NUM> can have the same number of protrusions <NUM> or a different number of protrusions <NUM> from one another.

The protrusions <NUM> can be arranged in a staggered configuration, where the rows 29rm are aligned two by two with two adjacent rows being shifted by a gap or pitch. In other words, five adjacent protrusions <NUM> can define a quincunx pattern or matrix, especially when the shifting gap corresponds to half the length, or interval, separating two protrusions <NUM> as illustrated in <FIG>. In other words, the protrusions <NUM> of the first 29ri and are aligned with the protrusions of the third row 29r<NUM> and the protrusions <NUM> of the second row 29rz and are aligned with the protrusions of the fourth row 29r<NUM>. The rows 29rm can be arranged in an irregular staggered configuration, where the shifting gap is different from one row to another, as illustrated in <FIG> or <FIG> where the first 29ri and third row 29r<NUM> do not have the same shifting gap in regards to the second row 29rz. In other words, the protrusions <NUM> of the first row 29ri and are not aligned with the protrusions of the third row 29r<NUM> and the protrusions <NUM> of the second row 29rz and can be aligned or not with the protrusions of the fourth row 29r<NUM>, the invention not being limited to a particular embodiment.

In a row 29rm, the protrusions are aligned and oriented in the same way, i.e. the axis P of each protrusions <NUM> in a row 29rm are parallel to each other. In other words, for each row 29rm, the protrusions <NUM> are arranged in the same orientation, each protrusion being spaced apart by an interval, said interval being equal or different from one protrusion <NUM> to the other. According to an embodiment, the protrusion <NUM> from one row 29rm to the next is rotated by an angle α comprised between <NUM>° and <NUM>°, preferably between <NUM> and <NUM>°, more preferably between <NUM>° and <NUM>° and even more preferably at <NUM>° as illustrated in <FIG>. In the embodiment as illustrated in <FIG>, the axis P of protrusions <NUM> that are in two rows 29rm separated by another row 29rm in between are parallel, in other words, the axis P of the protrusions <NUM> in the row 29ri is parallel to the axis P of the protrusions <NUM> in the row 29r<NUM>, the axis P of the protrusions <NUM> in the row 29rz being perpendicular to the axis P of the protrusions <NUM> in the row 29ri and row 29r<NUM>. According to another embodiment, the protrusions <NUM> all present the same orientation, i.e. all the axis P are parallel to one another.

The row 29rm and/or protrusions <NUM> can be evenly distributed, as illustrated in <FIG>, or irregularly distributed over the embossment pattern 29a.

The embossment pattern 29a, thus embossed surface <NUM>, spans over a certain degree β of the embossment roller <NUM>. Preferably, the embossment pattern 29a spans over <NUM>° to <NUM>° of the embossment roller <NUM>, more preferably, the embossment pattern 29A spans over <NUM>° to <NUM>°, even more preferably, the embossment pattern 29a spans over <NUM>° and <NUM>°, for example <NUM>°. In the embodiment where the embossment roller <NUM> comprises two embossment patterns 29a arranged on opposite side of the roller, said embossment patterns 29a, or embossed surfaces <NUM>, preferably span over the same circumferential length, i.e. the two embossment patterns 29a spans over the same degree value of the embossment roller <NUM>. This enables to have a laminated structure (that will be described after) that comprises a proper proportion of bonded and unbonded first web material <NUM> as illustrated in <FIG>. According to an alternative embodiment, the embossment patterns 29a can span over different degree value of the embossment roller <NUM>.

The embossment roller <NUM> comprises a succession of embossed surface <NUM> and smooth surface <NUM>. The embossment roller comprises at least one embossed surface <NUM> and at least one smooth surface <NUM>. Preferably, the embossment roller can comprise two embossed surfaces <NUM> and two smooth surfaces <NUM> where the embossed surfaces <NUM> are on opposite sides of the roller <NUM> and the smooth surfaces <NUM> are on opposite sides of the roller <NUM>, each smooth surface <NUM> being arranged between two embossed surfaces <NUM> and each embossed surface <NUM> being arranged between two smooth surfaces <NUM>. Of course the embossment roller <NUM> can comprise three, four, five or more embossed surfaces <NUM> and smooth surfaces <NUM>. Preferably, there is the same number of smooth surfaces <NUM> and embossed surfaces <NUM> on the embossment roller <NUM>. According to an alternative there can be more smooth surfaces <NUM> than the embossed surface or vice versa on the embossment roller <NUM>.

In one embodiment, the embossment roller <NUM> comprises a first embossed surface <NUM> covering <NUM>° of the embossment roller <NUM>, a smooth surface <NUM> covering <NUM>° of the embossment roller <NUM>, another embossed surface <NUM> also covering <NUM>° of the embossment roller <NUM> and another smooth surface <NUM> also covering <NUM>° of the embossment roller <NUM>. In this embodiment, the embossed surfaces <NUM> cover a bigger portion of the embossment roller <NUM> than the smooth surfaces <NUM> (<NUM>° to <NUM>°). The ratio r between the portion covered by the embossed surfaces <NUM> and the portion covered by the smooth surface is superior or equal to <NUM>, in other words the embossment roller <NUM> respects the following relation: <MAT>. Preferably the ratio is comprised between <NUM> and <NUM>, more preferably, the ratio is comprised between <NUM> and <NUM>, even more preferably, the ratio is comprised between <NUM> and <NUM>. For example, the portion of the embossment roller <NUM> covered by all the embossed surfaces <NUM> can cover <NUM> times the portion of the embossment roller <NUM> covered by all the smooth surfaces <NUM>. As explained above, the embossed portion of the embossment roller <NUM> corresponds to the bonding region <NUM> between the first and second web material <NUM>,<NUM>. It is preferable to have a higher bonding ratio. Although it could be possible to have an embossment roller <NUM> without any smooth surface, i.e. the embossed pattern 29a spans over the entire circumference of the embossment roller <NUM>, it is preferable to have a certain portion of smooth surface <NUM>, meaning non-bonded portions, for the sealing step that will be explained hereunder.

The first web material <NUM> and the strip of second web material <NUM> are combined at the combining roller <NUM>, the strips of second web material <NUM> laying on top of the first web material <NUM> forming a pre-bonded or combined structure. The combined structure is guided towards the bonding station <NUM>. As illustrated in <FIG> and <FIG>, the bonding station <NUM> comprises the embossment roller <NUM> and the ultrasonic welding device <NUM> which comprises an ultrasonic vibration generator <NUM> and the bonding sonotrode <NUM>, or probe. The ultrasonic welding device <NUM> is mounted vertically above the embossment roller <NUM>, leaving a small gap <NUM> between the outer surface of the embossment roller <NUM> and the bonding sonotrode <NUM>. The first web material <NUM> comes in contact with the embossment roller <NUM> either at a smooth surface <NUM>, at an embossed surface <NUM> or at their junction <NUM>. The protrusions <NUM> of the embossed surface <NUM> cause a local elevation of the second and first web material <NUM>,<NUM> as illustrated in <FIG>. While the bonding sonotrode <NUM> is constantly expanding and contracting at a certain frequency, the first and second web materials <NUM>,<NUM> are conveyed through the gap <NUM> between the bonding sonotrode <NUM> and the embossment roller <NUM>.

During the expansion phase, the bonding sonotrode <NUM> compresses the second web material <NUM> between the welding surface <NUM> of the bonding sonotrode <NUM> and first web material <NUM> as well as the embossment roller <NUM>. This compression creates molecular compression and surface friction, causing the second web material <NUM> to selectively melt at the protrusions <NUM> of the embossment roller <NUM>. More precisely, the compression and friction of the molecules create heat that melts selectively the second web material <NUM> at each protrusion <NUM> positioning. For this purpose, the second web material <NUM> comprises preferably, but not limited to, a nonwoven thermoplastic material, for example PolyEthylene (PE), Polyester (PET for example) or PolyPropylene (PP), or bicomponent fibres, for example and not limited to PE/Polyester. In a possible embodiment, the second web material <NUM> is a soft carded thermobonded nonwoven material with a smooth surface. The smooth surface aids in the application of the hygienic product. The second web material <NUM> is preferably hydrophilic, and can for instance be a <NUM>% mix of polyethylene (PE) and polyester, preferably polyethylene terephthalate (PET). Further characteristics of the second web material of the proposed embodiment is an area density of about <NUM>/m<NUM> (according to WSP <NUM>), a tensile strength at maximal force in the machine direction (lengthwise) of about <NUM> N/<NUM>, a tensile strength at maximal force in the cross machine direction (breadthwise) of about <NUM> N/<NUM>, an elongation at maximal force in the machine direction of about <NUM>%, an elongation at maximal force in the cross machine direction of about <NUM>% (all according to WSP <NUM>) and a liquid strike-through time (according to WSP <NUM>) of about <NUM>. These characteristics have been measured by WSP protocols.

According to one embodiment, the first web material <NUM> and the second web material are of different nature. More precisely, the first web material <NUM> comprises an absorbent material such as rayon, polyester or cotton fibers whereas the second web material <NUM> comprises a thermoplastic material as described above. The second web material <NUM> melts at lower temperature (<NUM>-<NUM>°) whereas the first web material <NUM> melts at higher temperature (around <NUM>°), therefore the vibrations transmitted by the bonding sonotrode <NUM> will melt specifically the second web material <NUM>. During the contraction phase, the bonding sonotrode <NUM> enables a bigger gap <NUM>, allowing the web materials to run through the gap at high speeds without material jams. With the local melting of the second web material <NUM>, said melting web material <NUM> penetrates into the voids present between the fibres of the first web material <NUM> thereby creating a bonding region <NUM> between the two web materials <NUM>,<NUM>. In other words, the bonding station <NUM> enables the formation of an at least partially laminated structure <NUM> where the first-end <NUM> of the strip of second web material <NUM> is bonded onto the first web material <NUM>.

The amount of energy brought into the second web material <NUM> depends upon the amplitude of the bonding sonotrode <NUM> and the force applied said material <NUM>. While the amplitude remains constant, the bond strength can be regulated by adjusting the gap <NUM>. Indeed, if the gap <NUM> is too high, less energy is applied to the second web material <NUM> resulting in weaker bonds whereas, if the gap <NUM> is too small, the bond will be stronger but there's a higher risk of jamming.

The ultrasonic welding device <NUM> can be calibrated to have an adequate gap <NUM>, or the ultrasonic welding device <NUM> can comprise an actuator unit with a height adjustment system configured to change the operating position of the bonding sonotrode <NUM> via a toggle mechanism.

The partially laminated structure <NUM> resulting from the bonding station <NUM> is as illustrated in <FIG>. It will be understood in the rest of the description that a partially laminated structure <NUM> corresponds to a partially bonded structure <NUM> or to a partially bonded first and second web material <NUM>,<NUM> without any limitation or restriction imposed to a term or its equivalent.

In this embodiment, the first web material <NUM> is provided with predetermined breaking points <NUM>, preferably along a line transversal to its longitudinal axis, equidistantly along its longitudinal axis, and is intermittently provided with strips of the second web material <NUM>, of a different length than between subsequent predetermined breaking points <NUM>. In this embodiment, the strips of second web material <NUM> are shorter than the distance between the subsequent predetermined breaking points <NUM> of the first web material <NUM>. A first-end <NUM> of strips of second web material <NUM> is partly bonded, passing through the bonding station <NUM> described hereabove, to the first web material <NUM>. Preferably, the bonding region <NUM> is arranged so that a part of the strip of second web material <NUM> extends beyond said end of the first web material <NUM> defined by the predetermined breaking points <NUM> as illustrated in <FIG>. Possible dimensions for the tampon are a length between subsequent predetermined breaking points <NUM> comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>, more preferably <NUM>, <NUM> or <NUM>, for the first web material <NUM>, and a length comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>, more preferably <NUM> or <NUM> for the strip <NUM> of second web material. The part of the strip of second web material <NUM> that is bonded <NUM> to the first web material <NUM> can for instance extend over a distance of <NUM>, up to <NUM>. The part of the strip of second web material <NUM> extending over the predetermined breaking point can extend over a distance of <NUM>. This configuration is possible by adjusting the ratio r (embossed surface/smooth surface) of the embossment roller <NUM>. In a particular embodiment, the tampon has the following dimensions: a length of <NUM> for the first web material <NUM> between two breaking points <NUM>, a length of <NUM> for the second web material <NUM> and a length of <NUM> for the bonded region <NUM>, the length of unbonded second web material <NUM> is of <NUM> in this embodiment. The first web material <NUM> is preferably wider than the second web material <NUM>. The width of the first web material <NUM> is comprised between <NUM> and <NUM> whereas the width of the second web material <NUM> is comprised between <NUM> and <NUM>.

It is preferable for the production process that the first web material <NUM> is provided with predetermined breaking points <NUM>, but not entirely separated, or too strongly weakened, in order for said second web material <NUM> to be pulled through the apparatus as a continuous stream. After the strips of the second web material <NUM> are bonded, it is possible to fully separate the first web material <NUM> at the predetermined breaking points <NUM>, thus creating identical partially laminated structure <NUM>, comprising both the first <NUM> and the second web material <NUM> bonded at the first-end <NUM> of the strip of second web material <NUM>. This partially laminated structure <NUM> can subsequently be rolled, according to a winding process that is detailed hereunder, in a matter as illustrated in <FIG>, with the first web material <NUM> on the interior of the tampon blank, and the second web material <NUM> covering the first web material <NUM> as an outer layer. After the tampon blank has been rolled, a sealing operation that is described hereunder can be executed to seal the outer layer of the second web material <NUM>, the original strip, as can be seen in <FIG>.

By carefully choosing the outer layer of second web material <NUM> and the first web material <NUM> itself, many advantageous effects are achieved, for instance it increases the stability of the tampon, thus reducing deformations and generating a more aesthetically pleasing appearance, which is instrumental in appealing to a customer and providing the assurance of quality of a hygienic and very intimate product. Furthermore, the application of the tampon is easier as the outer layer of the second web material <NUM> is smoother than the interior first web material <NUM>. This way, application of the tampon is made easier, while still allowing for optimal absorbance of menses and other fluids. Also, by having a stronger, smoother outer layer of second web material <NUM>, the interior first web material <NUM> is not exposed to the forces and frictions of the machinery it is run through and fibers of the interior material cannot detach themselves. If too many fibers would detach during the production process, not only would this cause deterioration in the produced tampons, but this could also clog up the machinery that produces the tampons. Lastly and most importantly, it is of the highest importance for the tampon that as few as possible absorbent fibers can detach themselves during use, as these could otherwise accumulate in the body of the consumer. By having a stronger, outer layer of second web material <NUM> as can be seen in <FIG>, the fibers of the interior first web material <NUM> will not detach as easily as they are less exposed to forces or frictions, and even should they detach themselves, will likely be contained within the outer layer of second web material <NUM>.

After the bonding station <NUM>, the partially laminated structure <NUM> is conveyed towards a winding station <NUM> that will be described hereafter, by a plurality of pulling rollers <NUM>,<NUM> as illustrated in <FIG>. The apparatus as illustrated in <FIG> comprises a first pair of rollers <NUM>, mounted on a first frame with a distance in between the first pair of rollers <NUM> that is smaller than the thickness of the partially laminated structure <NUM>. The apparatus can further comprise a second pair of rollers <NUM> mounted on the first or a second frame with a distance in between the second pair of rollers <NUM> that is smaller than the thickness of the partially laminated structure <NUM>. The distances in between said pairs of rollers <NUM>, <NUM> are thereby suitable for pulling the first and second web material <NUM>,<NUM>.

The first pair of rollers <NUM> is configured to rotate and thereby frictionally pull the endless laminated structure <NUM> with a first linear speed. The second pair of rollers <NUM> is configured to rotate and thereby pull the endless absorbent fiber <NUM> sheet with essentially the first linear speed. The rolls can thereby be driven by at least one motor.

During in-line processing, the partially bonded first and second web material <NUM>,<NUM> are propagated from the first pair of rollers <NUM> to the second pair of rollers <NUM>. From the second pair of rollers <NUM>, the partially laminated structured <NUM> is propagated to a pulling means. Preferably, the pulling means comprises a rotatable clamping means <NUM> for clamping the partially bonded first and second web material <NUM>,<NUM> sheet and for tearing off, namely at the breaking point <NUM>, and rolling up the partially laminated structure <NUM>. The tearing off and rolling up of the partially laminated structure <NUM> are thereby performed by the same rotational motion of the rotatable clamping means <NUM>.

The apparatus can comprise guiding means <NUM> to guide the partially bonded first and second web material <NUM>,<NUM> to the first pair of rollers <NUM> and/or from the first pair of rollers <NUM> to the second pair of rollers <NUM> and/or from the second pair of rollers <NUM> to the rotatable clamping means <NUM>. Preferably the guiding means <NUM> comprise one or more pairs of guiding blades <NUM>, each pair of blades <NUM> comprising a slit to guide the absorbent fiber sheet <NUM> in between the blades. The slit of each pair of guiding blades <NUM> is thereby thin enough for limiting substantial movement of the first and second web material <NUM>,<NUM>.

In a preferred embodiment, the rotatable clamping means comprises a cylindrical casing <NUM>, the cylindrical casing <NUM> comprising two slits to let through the teared up strip of partially bonded first and second web material <NUM>,<NUM>. The cylindrical casing <NUM> is suitable for spatially restricting a rolled-up tampon preform to prevent it from unrolling during and/or after the rolling up step.

The pulling force causes bursting along the breaking points <NUM> and the detached strip of partially bonded first and second web material <NUM>,<NUM> is spirally rolled up, or wound, to a tampon preform by the rotation of the rotatable clamping means <NUM>.

Once a spirally rolled-up tampon preform is formed on the rotatable clamping means <NUM>, either the tampon preform should be removed from the clamping means <NUM> or another rotatable clamping means <NUM> should be provided, before the new tip of the propagated endless partially bonded first and second web material <NUM>,<NUM> arrives. <FIG> schematically represents a preferred embodiment of the system of the present invention. The apparatus comprises a transferring device, in this embodiment a wheel <NUM> for conveying an at least partially rolled-up strip away from the endless web material sheet, the wheel <NUM> comprising a wheel axis in essence parallel to the transversal direction about which the wheel <NUM> can be rotated. The wheel in <FIG> comprises eight rotatable clamping means <NUM>. Each rotatable clamping means <NUM> comprises a cylindrical casing <NUM> for limiting the expansion of a spirally rolled-up detached strip of partially bonded first and second web material <NUM>,<NUM> sheet. The specific embodiment in <FIG> should not be interpreted as limiting. The wheel <NUM> can comprise any number of rotatable clamping means <NUM>, that number can be larger than or equal to two rotatable clamping means <NUM>, preferably at least four rotatable clamping means, more preferably at least six rotatable clamping means <NUM>. For example, the wheel <NUM> can comprise eight, ten, twelve, fourteen, sixteen, eighteen or twenty rotatable clamping means <NUM>. The wheel <NUM> can comprise more than twenty rotatable clamping means <NUM>.

When a first strip of partially bonded first and second web material <NUM>,<NUM> arrives at a first rotatable clamping means <NUM>, it passes through the slit of the first rotatable clamping means <NUM>. This slit is adjusted to rotatable clamping means <NUM> said sheet when the breaking point <NUM> enters the region in between the first pair of rollers <NUM> and the second pair of rollers <NUM>. After clamping, preferably shortly or immediately after clamping, the first rotatable clamping means <NUM> starts to rotate. The rotating clamping means <NUM> induces via the second pair of rolls which rotate in a freewheel-type manner a pulling force over the breaking point <NUM>, which causes the breaking point <NUM> to burst and the detached strip of the partially bonded first and second web material <NUM>,<NUM> sheet can then be rolled up to a spirally wound tampon preform. The wheel <NUM> is rotated, in <FIG> counterclockwise from the viewing perspective in <FIG>, but in another embodiment the rotation can be clockwise. A second rotatable clamping means <NUM> is thereby positioned, with its slit accordingly adjusted, to receive the new tip of partially bonded first and second web material <NUM>,<NUM> sheet, and the process is repeated. The spirally rolled-up tampon preform in and around the first rotatable clamping means <NUM> is then rotated by the wheel <NUM> to a sealing station <NUM> for sealing the second-end <NUM>, or free-end <NUM>, (illustrated <FIG> and <FIG>) of the second web material <NUM> that has not been bonded to the first web material <NUM> at the bonding station <NUM>.

According to the invention, the sealing station <NUM> comprises an ultrasonic welding device. The ultrasonic welding device comprises an ultrasonic vibration generator (not illustrated) and a sealing sonotrode <NUM>. The sealing station <NUM> is positioned at proximity of the wheel <NUM>. For example, the sealing station <NUM> can be arranged on the vertical top portion of the wheel <NUM> as illustrated in <FIG>. In other words, when the sealing station <NUM> is arranged on the vertical top position, or portion, of the wheel <NUM>, the axis passing through the sealing sonotrode <NUM> and the center of the wheel <NUM> is perpendicular to the axis passing through the pick-up location <NUM> (described hereunder) and the center of the wheel <NUM>. The rotatable clamping means <NUM> are calibrated in such a way that when the rolled-up, or wound, tampon preform comes up to the sealing station <NUM>, the free-end <NUM> is positioned on top so that the sealing sonotrode <NUM> can transmit the vibrational energy and selectively melt the second web material <NUM> in a process similar to the bonding station <NUM> as described above. The tampon preform is thereby sealed up with the outer layer corresponding to the second web material <NUM> around the absorbent material, or first web material <NUM> with a seal <NUM>, as can be seen in <FIG>.

In order to ensure that the tampon is correctly sealed, according to an embodiment, the sealing station <NUM> can comprise more than one sealing sonotrode <NUM>. According to different embodiments, the sealing station <NUM> can comprise one, two, three, four, five or more sealing sonotrodes <NUM>. This way, should the tampon be rotated too much or not enough resulting in the free-end <NUM> being offset from the sealing sonotrode <NUM> at the top position, the sealing sonotrodes <NUM> placed at different positions of the wheel <NUM> can melt the free-end <NUM> of the second web material thus properly sealing the tampon.

According to an embodiment, the sealing station <NUM> can comprise a deflecting plate near the sealing sonotrode <NUM> that is arranged in a manner as to ensure that the free-end <NUM> of the wound tampon stays within the cylindrical casing <NUM> and that said free-end <NUM> is properly guided to the sealing sonotrode <NUM> and its welding surface.

According to another embodiment, the sealing sonotrode <NUM> can be mounted mobile relative to the wheel <NUM>. The sealing sonotrode <NUM> can be arranged within a railing <NUM> system and follow a defined track <NUM>, or cam track, as illustrated in <FIG>. In order to be constantly in proximity to the wheel <NUM> and the rotatable clamping means <NUM>, the railing or track <NUM> is of complementary shape of the wheel <NUM>, i.e. the railing or track is curved, or arcuate. The sealing sonotrode <NUM> can move along the wheel <NUM> at the same speed of the wheel <NUM> in order to ensure that the tampon preform, which rotates thanks to the rotatable clamping means <NUM>, will inevitably pass through a position where the free-end <NUM> is in contact, or close to, the sealing sonotrode <NUM>. In this embodiment, the sealing sonotrode <NUM> is actuated and moves at an constant distance relative to the rotatable clamping means <NUM>. In other words, the tampon will be sealed since the free-end <NUM> is inevitably melted. The railing <NUM> can span over a degree comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°, more preferably between <NUM>° and <NUM>°, in other words the angle defined between the first end of the railing <NUM> and the opposite second end of the railing is comprised between these values, for example the railing <NUM> corresponds to an arc that extends up to <NUM>°.

According to another embodiment, the sealing station <NUM> can comprise two stationary sealing sonotrodes <NUM> and one mobile sealing sonotrode <NUM> arranged in between. The sealing station <NUM> can also comprise two mobile sealing sonotrodes <NUM>, for example moving in mirror or opposite directions, i.e. if one is moving clockwise then the other is moving counter-clockwise and vice versa.

According to another embodiment, the sealing station <NUM>, more specifically the sealing sonotrode <NUM> can comprise an elevating mechanism to enable the movement of the sealing sonotrode <NUM> on one axis. In other words, the sealing station <NUM> comprises a actuator and an at least partially linear rail <NUM>, or sliding guide <NUM>, to move the sealing sonotrode <NUM> up and down, or in this case radially closer or remoter to the wheel <NUM>, clamping means <NUM> and the clamped tampon blank. The elevating mechanism is preferably a reciprocating mechanism inducing a back and forth linear motion. Such elevating mechanisms can comprise for example and not limited to, scotch yoke, slider-crank, piston engine, traction elevator geared or gearless, turbine, spring. More specifically, the sealing sonotrode <NUM> can be fixed to a frame with said frame being actuated or moved back and forth in a linear movement by an elevating mechanism as described hereabove. This ensures that the sealing sonotrode <NUM> is in close contact with the free-end <NUM> of the tampon thereby improving the sealing step efficiency.

As illustrated in <FIG>, the wheel <NUM> comprises a pick-up location <NUM> corresponding to the point when the first strip of partially bonded first and second web material <NUM>,<NUM> arrives at a first rotatable clamping means <NUM> and passes through the slit of the first rotatable clamping means <NUM>. The wheel <NUM> also comprises a drop-off location <NUM> corresponding to the point where the tampon once sealed-up can then be picked-up by an arm or pushed out of the rotatable clamping means <NUM> and transferred to a compressive device to give the desired shaped to the tampon.

The ultrasonic welding takes up a few milliseconds, for example from <NUM> to <NUM> milliseconds. Thus, the tampon is sequentially, or intermittently, transferred from the pick-up location <NUM> to the drop-off location <NUM>. In other words, the tampon blank, sealed or unsealed, passes through intermediate stations <NUM> where the wheel <NUM> pauses for a few milliseconds and then rotates again. During these pauses, the sealing sonotrode <NUM> induces vibrations to the free-end <NUM> to melt the second web material <NUM> and seal-up the tampon. The picking or pushing of the sealed tampon at the drop-off location <NUM> is configured to take the same amount of time, i.e. a few milliseconds, or less time if the at least one sealing sonotrode <NUM> is mounted mobile in rotation along an arcuate railing <NUM>, given that the ultrasonic welding can be continuous. The same can be said for the amount of time to wind the tampon at the pick-up location <NUM>.

As illustrated in <FIG>, the wheel <NUM> comprises eight intermediate stations <NUM>, in which when the rotatable clamping means <NUM> all simultaneously reach an intermediate station <NUM>, the wheel <NUM> stops, or pauses, for a few milliseconds. Of course, the wheel <NUM> can comprise more rotatable clamping means <NUM> and intermediate stations <NUM>.

According to another embodiment, the sealing station <NUM> comprises a single sealing sonotrode <NUM> that is arranged at a position <NUM> which is shifted, or at an angle, from the top position as illustrated in <FIG>. As illustrated in <FIG>, the sealing sonotrode <NUM> is preferably positioned at an intermediate station <NUM> that is located after the pick-up location <NUM> and prior to the location arranged at the top of the wheel <NUM>. For example, the sealing sonotrode <NUM> can be arranged at a position of the wheel <NUM> which defines an angle of <NUM>° with the axis passing through the center of the wheel <NUM> and the pick-up location <NUM> as illustrated in <FIG>. Of course the sealing sonotrodre <NUM> can be arranged at a position of the wheel <NUM> defining said angle comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°.

Claim 1:
Method for manufacturing a tampon, comprising the steps of:
a. supplying a continuous first web material (<NUM>);
b. supplying a continuous second web material (<NUM>);
c. cutting strips of the continuous second web material (<NUM>), whereby the strips are cut transversally, preferably perpendicularly, with respect to a longitudinal axis of the continuous second web material (<NUM>) and equidistantly repeated over the longitudinal axis of the continuous second web material (<NUM>);
d. bonding a first-end (<NUM>) of the strip of second web material (<NUM>) to the continuous first web material (<NUM>), thereby forming a partially laminated structure (<NUM>) at a bonding station (<NUM>);
e. conveying said partially laminated structure (<NUM>) to a winding station (<NUM>);
f. clamping the partially laminated structure (<NUM>) by rotatable clamping means (<NUM>) and rolling-up the clamped partially laminated structure (<NUM>), thereby separating the partially laminated structure (<NUM>) into strips along breaking points;
g. winding the partially laminated structure (<NUM>) strip so that the strip of second web material (<NUM>) forms the outer layer around the first web material (<NUM>);
h. transferring the wound partially laminated structure (<NUM>) strip to a sealing station (<NUM>); and
i. sealing the second-end (<NUM>) of the strip of second web material (<NUM>) to the first web material (<NUM>) and/or second web material (<NUM>),
characterized in that the sealing step comprises ultrasonic bonding, wherein the bonding step concurrently comprises an embossing step where the bonding station (<NUM>) comprise an embossment roller (<NUM>) that has spaced apart protrusions (<NUM>), the partially laminated structure being arranged in a way that the first web material (<NUM>) comes into contact with the embossment roller (<NUM>).