Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2001-02-12
2002-10-08
Vanatta, A. (Department: 3765)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C156S060000, C604S385010, C604S385240, C604S385160, C604S385220
Reexamination Certificate
active
06462251
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a composite laminated structure comprising a substrate and an apertured layer joined together by means of a layer of an adhesive composition. The laminated structure is made extensible in designated zones by mechanical straining and preferably constitutes side flaps in a disposable absorbent article such as a sanitary napkin.
BACKGROUND OF THE INVENTION
Absorbent articles such as sanitary napkins, pantiliners, and incontinence pads are devices that are typically worn in the crotch region of an undergarment. These devices are designed to absorb and retain liquid and other discharges from the human body and to prevent body and clothing soiling. Sanitary napkins are a type of absorbent article worn by women in a pair of panties and is normally positioned between the wearer's legs, adjacent to the perineal area of the body. Sanitary napkins in particular with side wrapping elements, often also referred to as side flaps or wings, are disclosed in the literature and are available in the marketplace.
Sanitary napkins having wings or side flaps of various types are disclosed in U.S. Pat. Nos. 4,687,478, 4,608,047, 4,589,876, Reexamination B1 4,589,876, 4,285,343. Sanitary napkins having wings are commonly viewed as providing good protection against soiling.
However, some women find applying sanitary napkins having side flaps to be inconvenient for various reasons. For instance, some women find it to be difficult to attach the side flaps to the underside of the crotch of their panties. This can be due to factors such as difficulties in folding the side flaps properly into place and to stick them to the undergarment As a result, some women still prefer a sanitary napkin without side flaps. In addition, some women who generally prefer a sanitary napkin with side flaps, occasionally (such as during periods of light flow) prefer a sanitary napkin without. Therefore, there is a need for a sanitary napkin which provides an alternative to sanitary napkins having conventional side flaps while still providing a similar protection.
Several variations of sanitary napkins having conventional side flaps have been suggested. For example, U.S. Pat. No. 4,911,701 discloses a sanitary napkin having elastic strands for providing a greater convex shape to the body-facing portion of the central absorbent and for enabling adhesive-free placement of the side flaps into the panties. U.S. Pat. No. 4,940,462 discloses a sanitary napkin with longitudinally expandable flaps. The flaps are designed to fold over the exterior of the wearer's panty and then to expand to conform with the contour of the panties. Further improvements of side wrapping elements with extensible zones have been disclosed in U.S. application Ser. No. 08/124,180 of Sep. 17, 1993; and Ser. No. 08/277,733 of Jul. 20, 1994 and European application 94202252.6 of Aug. 3, 1994.
In these disclosures the extensibility can be provided by a number of different processes. For example the extensible zones can be created by mechanically straining, corrugating, “ring-rolling”, heating and deforming, subjecting portions of the side wrapping elements or flaps to compression between mating plates, and the like.
In particular high speed mechanical straining such as corrugating or ring-rolling are desirable due to the manufacturing efficiency from allowing high speed production. Also ring-rolled zones of extensibility can have an angled extensibility relative to the machine direction (process transport direction). Suitable methods for ring-rolling, typically by means of two rolls of meshed interlocking teeth and grooves, are described in U.S. Pat. Nos. 4,107,364, 4,834,741, 5,143,679, 5,156,793 and 5,167,897.
Particularly preferred side wrapping elements or flaps comprise at least two layers of material but sometimes more, for example four layers of materials which are joined together forming a composite laminated structure that is rendered extensible only after being formed into a laminate. In particular prior art sanitary napkins with side wrapping elements having extensible zones are constructed such that the side wrapping elements are formed by laterally extending parts of the uppermost layer of the sanitary napkin (typically called topsheet) and the lowermost layer of the sanitary napkin (typically designated the backsheet).
The laminate formed in the area laterally outside the main portion of the sanitary napkin is strained by mechanical processes like the aforementioned ring-rolling at the production speed of these articles. For the laminate to display uniform behaviour during the mechanical straining the individual layers need to be properly joined to each other at least in the areas of mechanical straining.
Typically adhesives, especially hot melt adhesives have been suggested and used for that purpose. A large variety of adhesives for the different situations occurring in the manufacturing process of disposable absorbent articles have been developed and continue to be developed. Alternative joining methods include welding which is used between plastic materials of similar kinds allowing to create areas were the materials are fused to each other to create permanent connections, or crimping which is a local mechanical deformation of the layers such that the layers interlock locally.
A problem encountered when applying mechanical strain, for example by means of a ring rolling process, to a composite laminated structure comprising an apertured layer joined by means of an adhesive to a substrate, in order to provide designated zones of the structure with extensibility, is that machinery parts, typically the apexes of the metal teeth of one of the rolls used in the ring rolling process, come into direct contact with the adhesive layer through the apertures of the apertured layer. The apertured layer can be a nonwoven or, preferably, an apertured three dimensional polymeric film, constituting e.g. the topsheet of a sanitary napkin, and the substrate can be a liquid impermeable polymeric film, preferably a liquid impermeable, moisture vapour permeable layer, such as a microporous breathable film, comprised in a preferably breathable backsheet.
Adhesives used in the field of disposable absorbent articles are tackified to display adhesive characteristics over a broad range of temperatures. They are usually still tacky at room temperature and therefore during the mechanical straining step by means of e.g. ring rolling they can still stick to the teeth of a roll for ring rolling through the apertures of the apertured layer.
It is particularly undesirable during the straining process to have exposed adhesive on the outside of any of the laminates because adhesive build up, in particular sticky adhesive build up on fast moving machinery parts quickly leads to unstable process conditions. As a minimum the occurrence of these conditions require frequent cleaning but can even cause disastrous material destruction leading to machine stops and reduce efficiency. Particularly, when a ring rolling process is performed and one of the layers of the laminated structure has apertures the adhesive that sticks to the apexes of the teeth of one of the rolls can pull the portions of the layer joined to the apertured layer, i.e. the substrate, through the apertures of the apertured layer, to the extent that ruptures and pin holes are created in this substrate. This is detrimental to the integrity of the structure, and also to the liquid imperviousness of the substrate, when, as it is preferred, it constitutes at least part of a backsheet structure in a disposable absorbent article, and therefore ruptures in the substrate ultimately can cause liquid leakage during the use of the product.
This pulling action is even more effective in case of a composite laminated structure comprising a three dimensional apertured thermoplastic polymeric film as the apertured layer and a microporous breathable film as the substrate, since the presence of the micropores in the microporous film makes the film somewhat weaker and more s
Bonelli Guido
Carlucci Giovanni
Cimini Carmine
Cummings Theodore P.
Grayson Angela J.
Johnson Kevin C.
The Procter & Gamble & Company
Vanatta A.
LandOfFree
Mechanically strainable composite laminated structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mechanically strainable composite laminated structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mechanically strainable composite laminated structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2997999