The invention relates to a disposable hygiene article or surgical covering item, or surgical garment for single use, such as an incontinence diaper, incontinence pad, surgical drape, or surgical coat, comprising a composite nonwoven fabric, that is provided with at least one nonwoven fabric component and another nonwoven fabric or foil component. The first nonwoven fabric component is attached to the other nonwoven fabric or foil component in at least some areas by means of a joining pattern encompassing discrete ultrasonic welding points in order to form the composite nonwoven fabric. The joining pattern extends in a first direction and a second direction that runs perpendicular thereto, the distance in the first direction being longer than the distance in the second direction. At least some sections of the joining pattern are not rectilinear.
For example, on hygiene articles, in particular, incontinence products, such as incontinence diapers, lateral barriers standing toward the user during use, called cuff elements, are provided that comprise a nonwoven fabric component and are attached in the longitudinal direction of the product to another nonwoven fabric or foil component of the hygiene article by means of ultrasonic welding or bonding. In the field of the hygiene articles addressed here, the joining of nonwoven fabric and/or foil components by means of ultrasonic welding devices is generally known. For example, a joining pattern comprising discrete ultrasonic welding points can be implemented in a continuous, that is, never-ending production machine for nonwoven articles of the type stated above by using a contour roller rolling in the machine direction and an anvil made to vibrate in the ultrasonic range, which is termed a sonotrode. The contour roller and sonotrode form a gap between them through which the weldable components to be joined are fed during the continuous production process. The nonwoven fabric or foil components are then welded by transfer of the vibration energy on the raised areas of the contour roller. The strength of the weld can be adjusted by varying the distance between the sonotrode and the contour roller and by controlling the vibration of the sonotrode.
The applicant has ascertained that, in particular, on fast-operating production machines, it is extremely difficult to achieve a uniformly secure weld without damaging the components if the area of the weld varies greatly in the machine direction, because this necessitates very frequent variation in control of the welding device or its sonotrode. It is extremely difficult to almost impossible to achieve a stable operating condition. If, on the other hand, the area of a joining pattern varies little or not at all in the machine direction, for example, if it does not vary in the circumferential direction of the contour roller and, for example, comprises concentric embossing lines or embossing points on the contour roller, the problem described above does not occur because the welded area does not change so rapidly in the machine direction. If, on the other hand, the joining pattern is oblique with respect to the machine direction or comprises oblique sections, the proportion of the welded area in the machine direction will vary greatly and the problems described above will occur. If, for example, on one product, the joining pattern comprises arc-shaped areas with tight curvature with respect to the machine direction, achieving process reliability in the welding of nonwoven fabric components poses a problem. If this problem is not solved, unwelded points or damage to the nonwoven fabric or foil components due to overwelding will occur. In either case, correct functioning of the article being produced is jeopardized. Extremely short control cycles in operating the ultrasonic welding device can also result in the device overshooting and frequently causing direct contact between the contour roller and the sonotrode. This results in damage to the device, considerably reducing its service life. The sonotrode and contour roller then require frequent replacement due to the high wear caused by direct contact between the two machine components.
The object of this invention is to provide a hygiene article or a surgical covering item or surgical garment of the type described above with which the problems described above do not occur, while nevertheless permitting production of a joining pattern of discrete ultrasonic welding points that varies in the machine direction. For example, it must be possible to fix a standing cuff element according to a joining pattern that oscillates in the form of arcs with respect to the machine direction or generally to join weldable nonwoven fabric or foil components of the article stated above fed in as flat material without being limited to a joint that is precisely rectilinear in the machine direction. In particular, damage to components being welded together during the welding process and partially deficient welding of the components must be precluded. Similarly, damage to the ultrasonic welding device must be avoided and a long service life ensured in conjunction with fast-operating production machines.
This object is inventively achieved in an article of the type stated above by ensuring that the index of variation of the area seized by the ultrasonic welding points is no more than 40%. The solution is to design the joining pattern of the ultrasonic welding points in such a way that the area seized by the welding in the machine direction does not vary so much that the problems described above occur. For example, this can be achieved by variation and appropriate disposition of the number of ultrasonic welding points per unit area, that is, e.g. by selecting the distance between the ultrasonic welding points and/or by varying the respective area of the ultrasonic welding points.
The index of variation of the area seized by the ultrasonic welding points is calculated as follows: The article in accordance with the invention is considered divided into 5-mm wide longitudinal sections in the first direction. These longitudinal sections therefore extend over 5 mm in the first direction, which is also the machine direction, and perpendicular thereto in the second direction, which is the transverse direction on the product. Each of these sections extending 5 mm in the longitudinal direction encompasses a number of ultrasonic welding points, each of which constitutes a welded proportion of the area. It is possible to calculate the welded area Ai of each 5-mm section (sum of the areas of the individual ultrasonic welding points in a 5-mm section). It is also possible to calculate a mean value Ā of the area Ai seized by the ultrasonic welding points of each section. For example, it is possible to divide an 820-mm long article into 164 such 5-mm sections in the first direction. For each section, it is possible to calculate the welded area Ai and from these 164 Ai values, it is then possible to calculate the arithmetic mean Ā of the welded area of the 5-mm sections. A value s can be calculated from these according to the following formula:
Thus the error sum of squares of Ai of the individual 5-mm sections is calculated from the mean value Ā of the welded surfaces of the 5-mm sections and divided by (N−I) and the square root is taken of the result. Based on this, the said index I (in %) of variation of the area seized by the ultrasonic welding points is defined as follows:
It has been shown that the range of the index of variation of the area seized by the ultrasonic welding points of no more than 40% that is stated in the claims is suitable, in particular, for the machine velocities relevant here of 100 m/min to 1000 m/min, in particular, of 150 m/min to 700 m/min, to ensure process reliability of the ultrasonic weld joint between nonwoven fabric components and/or foil components of the articles in question here. It has proven especially advantageous if the index of variation of the area seized by the ultrasonic welding points is no more than 35%, in particular, no more than 30% and further, in particular, no more than 25% (claim 2).
This invention proves especially advantageous on an article in which the composite nonwoven fabric comprises on both sides at least one cuff element standing at least in sections, forming a leakage barrier, and essentially extending in the first direction (claim 3). As mentioned above, a cuff element is a lateral barrier formed from a flat material that is raised from the substrate mostly due to elastification, in particular, toward the body of the user and thus provides a leakage barrier, chiefly at the sides of the article. In the case of an inventive article, this cuff element is joined to further (chassis) nonwoven fabric or foil components of the article by an inventively constituted joining pattern of ultrasonic welding points. The cuff element therefore advantageously also comprises the first nonwoven fabric component (claim 4).
In particular, if the article according to the claims is a hygiene article for single use, it proves advantageous if the article comprises a topsheet that is permeable at least in some areas, a backsheet that is impermeable at least in some areas, and a storage core that absorbs body fluids and is disposed between the two (claim 5). In such a case, it can be advantageous for the other nonwoven fabric or foil component to be the topsheet or the backsheet, so that a preferably additionally provided cuff element with its first nonwoven fabric component is attached to the topsheet or backsheet by the inventive joining pattern of ultrasonic welding points (claim 6).
To join a cuff element to further components of the article by means of ultrasonic welding, it proves advantageous if the joining pattern comprises a first partial joining pattern that, at least in areas, constitutes a cuff base, that is, an area along which the cuff element is attached to the further nonwoven fabric component or foil component (claim 7). When the article is put to its intended use, this then constitutes a fold line along which the cuff element is raised away from a base plane.
In a further embodiment of this inventive concept, the cuff base constituted in some areas by the said first partial joining pattern can additionally be constituted or limited in some areas by a second partial joining pattern that is largely rectilinear and, in particular, largely extends parallel to the first direction (claim 8). Here and hereafter a partial joining pattern is referred to as largely rectilinear when, over a length of 200 mm in the first direction, an extension in the second direction of no more than 6 mm can be ascertained.
In yet a further embodiment, the cuff base is constituted at least in sections by the first partial joining pattern, the second partial joining pattern and a third non-rectilinear partial joining pattern (claim 9). In the first direction, the second partial joining pattern is disposed preferably between the first and the third partial joining pattern (claim 10). The result is therefore a cuff base that, in a front area and in a rear area of the article, extends transverse to the longitudinal direction, in particular, curved in the shape of an arc with respect to the longitudinal direction and, in the intermediate area, is largely rectilinear and, in particular, parallel to the first direction. Such a configuration proves especially advantageous, particularly for hygiene articles for single use, such as incontinence diapers, incontinence pads. The invention makes it possible to dispose the cuff elements relatively far toward the outside in the transverse direction in a front and rear region of the article and then to have them curve inward toward the crotch area. In the crotch area, the cuff elements or the cuff base or cuff base lines then advantageously extend largely parallel and have a smaller distance between them in the transverse direction (second direction) than in the front and rear areas. With this invention, it becomes possible to establish a stable connection between the cuff element and chassis materials of a hygiene article that meets the desired requirements for configuration of the article and is nevertheless producible with process reliability by complying with the inventive design of the joining pattern.
In a further embodiment of the invention, it proves advantageous if, in an inventive article, the joining pattern in the first direction is considered virtually in three sections of equal length, that is, is divisible into a start section, an adjoining center section, and an end section adjoining the center section and the index of variation of the area of the start section and/or of the end sections seized by the ultrasonic welding points of the joining pattern is no more than 40%, in particular, no more than 35%, further, in particular, no more than 30%, further, in particular, no more than 25% (claim 11). According to this further embodiment of the invention, the inventively imposed condition is not only fulfilled over the entire claimed article, considering all 5-mm sections containing ultrasonic welding points, but also for the corresponding 5-mm sections of the start section overlapping by one third and the end section overlapping by one third.
As already stated, the inventive design of the joining pattern of the ultrasonic welding points can be achieved by various measures. In particular, it can prove advantageous if the distance between the discrete ultrasonic welding points is smaller in a first area than in a second area (claim 12).
In particular, it proves useful if the distance between individual (discrete) ultrasonic welding points in a first area is 0.1 to 2.5 mm, in particular, 0.2 to 1.5 mm, and further, in particular, 0.2 to 1.0 mm and, in a second area, is 2 to 20 mm, in particular, 3 to 15 mm, further, in particular, 4 to 10 mm (claim 13).
It is also possible for the density per unit area of the ultrasonic welding points (number of points per unit area) to be greater in a first area than in a second area (claim 14).
The said first area is a partial area of the joining pattern; it can constitute, in particular, one partial area of the first and/or second and/or third partial joining pattern of the cuff base (claim 15).
According to a further embodiment of the invention, the first and/or third partial joining pattern comprises a set of at least two, in particular, at least three curves, further, in particular, at least four, further, in particular, at least five curves (claim 16). Preferably at least two of the curves of a set should be separated by a small maximum distance of 2 to 20 mm, in particular, 2 to 15 mm and further, in particular, 3 to 10 mm (claim 17). Furthermore, it proves advantageous if at least two of the curves of a set are separated by a greater maximum distance of 10 to 70 mm, in particular, 15 to 60 mm and further, in particular, 20 to 50 mm (claim 18). For example, this is possible and advantageous if the set consists of three curves and the maximum distance of the first outer curve from the center curve has the previously stated low value and the maximum distance of the second outer curve from the center curve is a greater distance. Of course, in the case of a set of more than three curves, at least two curves of a set can have a different maximum distance between them.
Moreover, it proves advantageous if one or more of the curves has a radius of at least 60 mm, in particular, at least 70 mm, further, in particular, 80 mm, further, in particular, at least 90 mm, further, in particular, at least 100 mm and further, in particular, no more than 150 mm (claim 19). The curves can also have a variable distance between them (claim 20).
The curves are advantageously not a weld line that is continuous over its extension but a series of consecutive ultrasonic welding points that is then largely linear and thus forms the curve. By varying the distance between the ultrasonic welding points and/or by changing the distance between the curves it is possible to vary the proportion of the area of the weld points in each 5-mm section, so that, overall, the claimed index range is complied with.
It proves advantageous if the joining pattern has first discrete ultrasonic welding points with an area of 0.3 to 4 mm2, in particular, 0.3 to 3 mm2, further, in particular, 0.3 to 2 mm2, further, in particular, 0.5 to 1.1 mm2 and further, in particular, 0.7 to 0.9 mm2 (claim 21).
As already stated, it can be advantageous if the joining pattern encompasses first and second discrete ultrasonic welding points and the area of the first discrete ultrasonic welding points is smaller than that of the second discrete ultrasonic welding points (claim 22).
The shape of the area of the ultrasonic welding points is relatively uncritical; they can be circular or oval or triangular or polygonal or sickle-shaped or dot-and-dashed or star-shaped or linear (claim 23).
For example, in the production of hygiene articles, it can prove advantageous if the sum (Ai) of the areas of the ultrasonic welding points of a 5-mm long section of the joining pattern in the first direction is on average 2 to 25 mm2, in particular, 3 to 18 mm2, in particular, 4 to 12 mm2 and further, in particular, 6 to 10 mm2 (claim 24). In the case of a hygiene article with cuff elements on both sides, these are preferably the values that apply to the joining pattern of one of the cuff elements.
Furthermore, it proves advantageous if the sum (Ai) of the areas of the ultrasonic welding points of one, in particular, each 5-mm long section of the joining pattern in the first direction is no more than 30 mm2, in particular, no more than 23 mm2, further, in particular, no more than 18 mm2, further, in particular, no more than 16 mm2, further, in particular, no more than 15 mm2 (claim 25).
In the production of an inventive article, it proves advantageous if, in the design of the joining pattern of the ultrasonic welding points, the deviation of the sum (Ai) of the areas of the ultrasonic welding points of each 5-mm long section of the joining pattern in the first direction from the sum (Ai) of the areas of the ultrasonic welding points of a directly adjacent 5-mm long section of the joining pattern is less than 70%, in particular, less than 60%, in particular, less than 50%, further, in particular, less than 40% (claim 26). This means that the entire welded area (Ai) of two adjacently disposed 5-mm sections must differ by no more than the above-mentioned ranges. In this case, this deviation of two adjacent 5-mm long sections refers to the sum Ai of the areas of the ultrasonic welding points of the section whose sum Ai of the areas of the ultrasonic welding points has the higher value.
Furthermore, it proves advantageous with respect to consistent product quality if the deviation of the sum of the areas of the ultrasonic welding points of at least 50%, in particular, of at least 60%, further, in particular, of at least 70% and further, in particular, of at least 80%, and, very especially, of at least 90% of the 5-mm long sections of the joining pattern from the sum (Ai) of the areas of the ultrasonic welding points of a directly adjacent 5-mm long section of the joining pattern is less than 40%, in particular, less than 30%, in particular, less than 25% (claim 27).
The invention also relates to a method for the production of a hygiene article or surgical covering item, or surgical garment of the inventive type with the characteristics stated in the claims 29, 30, and 31.
Furthermore, it proves advantageous if the claimed article is constituted such that the joining pattern extends 300 to 2000 mm, in particular, 350 to 1500 mm, in particular, 400 to 1200 mm, further, in particular, 450 to 1100 mm and further, in particular, 500 to 1000 mm in a first direction and running perpendicular thereto preferably 10 to 1200 mm, in particular, 15 to 1000 mm, in particular, 20 to 500 mm, further, in particular, 30 to 200 mm and further, in particular, 40 to 150 mm and further, in particular, 50 to 130 mm in a second direction.
Further characteristics, details, and advantages of the invention can be seen from the appended patent claims and from the drawings and the following description of the invention using explanatory examples. The drawings show:
Laterally extending side flaps 22 and 24 are provided in a respective front area 18 and in a respective back area 20. The side flaps 22, 24 extend between topsheet 4 and backsheet 6 and are fixed there by welding or gluing. A weld or glue line is indicated with reference symbol 26.
Moreover, the cuff elements 14 of both sides are joined in a first area 27 along a so-called cuff base 28 and in a second area 29 with the nonwoven fabric component 10 of the topsheet 4 by discrete ultrasonic welding points 30 forming a joining pattern. The discrete ultrasonic welding points 30 have a maximum distance between them of 0.1 mm to 2.5 mm in a first area 27 and a maximum distance between them of 4.0 mm to 10.0 mm in a second area 29 and have an area of 0.7 to 0.9 mm2 in each case. The extent of the cuff base 28 is best visible in
It would be possible and advantageous, in an embodiment not shown here, to fix the cuff base 14 directly to the backsheet 6 by means of the joining pattern. This would be advantageous, in particular, if the cuff base 14 were outside the absorption body contour and outside the transverse extent of the topsheet 4.
Hygiene article 2 furthermore has a first direction 32 that constitutes the longitudinal direction of the hygiene article and matches the machine direction during production of the hygiene article. In continuous production, the topsheet 4, backsheet 6, side flaps 24, and cuff elements 14 constituting the corresponding webs of flat material therefore extend in this first direction 32. The cuff base 28 or the series of ultrasonic welding points 30 also largely extends along this first direction 32. However, as can be seen in
The schematic representation of an ultrasonic welding device designated in its entirety with reference sign 40 in
During production of the hygiene articles shown in
On the circumference of the contour roller 42, numerous protrusions 46 can be seen that are disposed and constituted according to the joining pattern 36 to be produced.
It is also possible to calculate a value s from the error sum of squares of the individual Ai values from this mean value Ā according to the following formula:
From this, it is possible to derive an index I of variation of the area seized by the ultrasonic welding points in the first direction 32 for the entire joining pattern 36 or the conceptual division into N 5-mm sections 48 as follows:
It was inventively determined that this index of variation of the area seized by the ultrasonic welding points 30 should be no more than 40% in the first direction 32.
Based on
The lower part of
If the joining pattern 36 is divided into a start section 50, a center section 52, and an end section 54 that each extend over a third of the extent of the joining pattern 36 in the longitudinal direction, the following values are obtained for these sections 50, 52, 54 when the N/3 5-mm sections contained in them are each evaluated in isolation:
Start section: Ā=9.55, s=4.66, I=48.8%
Center section 52: Ā=7.62, s=0.71, I=9.3%
End section 54: Ā=9.90, s=4.49, I=45.3%.
Due to this value of the index I of variation of the area seized by the ultrasonic welding points, a hygiene article with the joining pattern 36 shown in
An inventive joining pattern 36 is shown in
Start section: Ā=9.56, s=1.67, I=17.5%
Center section 52: Ā=7.34, s=0.91, I=12.4%
End section 54: Ā=9.25, s=2.33, I=25.1%.
It can be seen from
It is immediately apparent that there are several ways of ensuring that the variation of the area proportions Ai of the 5-mm sections in the first direction 32 is not too large. A first possibility is to keep the radius of curvature of curved partial joining patterns as large as possible, that is, not to permit tight curvature. A further possibility, which is shown in
Finally,
Number | Date | Country | Kind |
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10 2006 046 420.6 | Sep 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2007/008134 | 9/19/2007 | WO | 00 | 3/10/2009 |