Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1994-11-25
2001-07-24
Dixon, Merrick (Department: 1774)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S164000
Reexamination Certificate
active
06264784
ABSTRACT:
FIELD OF THE INVENTION
The current invention concerns a method and apparatus for making absorbent articles. More specifically, the invention concerns a method and apparatus for forming and attaching tabs onto an absorbent article designed to be worn in the perineal area of the body, such as sanitary napkins, incontinence pads and the like. The current invention also concerns an absorbent article made by the apparatus and method.
BACKGROUND OF THE INVENTION
Traditionally, absorbent articles have included a central absorbent element having a body facing side, a garment facing side, longitudinally extending sides and transverse ends. These articles generally include an absorbent core made of loosely associated hydrophilic materials such as wood pulp. These prior art products are held in place by providing areas of pressure sensitive adhesive on the garment facing side to adhere it to the inner crotch surface of the wearer's undergarment.
One drawback of prior art absorbent articles has been that in the course of wearing the absorbent article, the shape of the absorbent article tends to deform and the article tends to move out of position, thereby reducing its effectiveness. Recent designs have addressed this problem by including tabs or wings that extend laterally from the longitudinal sides of the central absorbent and wrap around the edges of the undergarment. See U.S. Pat. No. 4,285,343 (McNair); U.S. Pat. No. 4,589,876 (Van Tilburg); and U.S. Pat. No. 4,911,701 (Mavinkurve). However, the use of such tabbed articles presents several problems.
First, such tabbed absorbent articles were previously made with integral tabs by (i) cutting a tabbed article shape from an extra-wide strip of laminate formed from layers of body fluid pervious and impervious materials and (ii) inserting a central absorbent core between the layers. However, this method has several disadvantages. First, there is considerable wastage due to the excess material remaining after the tabbed article shape is cut from the large strip. Second, the tab material is limited to that suitable for an absorbent article cover.
Recently, absorbent articles have been developed which have separately formed tabs which are attached to the garment facing side of the napkin—see U.S. Pat. No. 4,900,320 (McCoy). Consequently, it would be desirable to develop a method and apparatus for forming such separate tabs and attaching them to absorbent articles which (i) made efficient use of tab material, (ii) allowed the tabs to be made from a range of materials beyond those suitable for article covers and (iii) provided flexibility in terms of the location and orientation of the tabs on the article.
The second problem associated with the use of tabbed articles arises because adhesive strips are typically applied to both the tabs and the central portion for attaching the article to the user's undergarment. These adhesive strips are often covered with separate protective release strips which act to protect the adhesive from dirt and unintended adhesion during manufacture, packaging and storage. These release strips must be removed by the user just prior to application of the product. Multiple adhesive elements and release strips, however, can present the user with a cumbersome process when preparing the product for use. The user often has to remove all three release strips (one on the central absorbent core and one on each of the tabs) while simultaneously making sure that the tabs do not inadvertently adhere to one another or to another part of the product. In particular, the user must carefully handle the product when removing the release strip on one tab in order to avoid inadvertently contacting the exposed adhesive on the other tab and the central portion, thereby rendering the product useless. Even when the problem of undesired adhesion is avoided, the user is presented with the task of disposing of three release strips.
Accordingly, absorbent articles have been developed in which a single release strip, coated on both sides with silicone or the like, is used to protect the adhesive strips on both the central portion and tabs, so that a single pull of a release strip is sufficient to ready the article for use—see U.S. Pat. No. 4,701,178 (Glaug et al.). However, such double sided release strips are more expensive than the standard single sided release strips and present problems in manufacture because they are difficult to handle due to the slipperiness of both of their sides. Thus, a need exists for a tabbed absorbent article having a user-convenient arrangement in which a single pull of a release strip is sufficient to remove the release material covering both the central portion and tab adhesive strips yet which utilizes standard single sided release paper.
A third problem is that even though the tabs help to stabilize the article, as a result of forces imposed on it during use, the article may still shift and deform, causing a phenomenon known as “roping,” whereby the napkin is crushed transversely inward and its edges are curled around its longitudinal axis so that the napkin eventually takes on the appearance of a twisted rope. This situation causes discomfort to the user and a loss of product effectiveness. Although it is known to attach the tabs along the longitudinal edges of the central portion of an absorbent article—see U.S. Pat. No. 4,285,343 (McNair)—there is a need for an absorbent article having tabs which are attached to the longitudinal sides of the central portion in such a way as to aid the article in resisting such lateral deformation.
SUMMARY OF THE INVENTION
It is an object of the current invention to provide a method and apparatus for efficiently making absorbent articles having attached tabs.
It is another object of the invention to provide a method of making and attaching the tabs which allows flexibility in the selection of tab material and in the placement and orientation of the tabs on the absorbent article.
It is still another object of the invention to provide an absorbent article having adhesive strips on both the central portion and the tabs which are protected by single sided release strips and yet which can be readied for application to an undergarment by a single pull on one release strip.
It is yet another object of the invention to provide an absorbent article having tabs which are attached in such a way as to aid the absorbent article in resisting lateral deformation.
These and other objects are accomplished using a method and apparatus whereby a pressure sensitive adhesive covered by a release strip is affixed to a strip of tab material. A continuous cut is made in the strip of tab material so that the cut alternates from side to side transversely across the centerline of the strip. The cut is made using a rotary die having a knife blade circumferentially extending around a drum in an approximately sinusoidal shape. As a result of this cut, the strip of tab material is transformed into two nested strips of tabs. The tabs in each strip face inward and are aligned in an offset fashion. In one embodiment of the invention, each of the strips is rotated approximately 180° so that the tabs face outward. The tabs are then spaced apart and realigned so that the tabs from each strip are in an in-line alignment. The realignment is done by separating the strips, conveying one strip a predetermined distance greater than the other strip and then bringing the tab strips together again. In one embodiment, realignment is accomplished by passing each tab strip around separate drums, the drums being spaced apart a predetermined distance equal to one half the tab pitch. The tab strips are then cut into tab pairs. The tab pairs are transported by a vacuum drum and deposited onto a strip of absorbent article to which an adhesive has been applied. The tabs are then folded over the strip and the strip is cut into individual absorbent articles. In an alternate embodiment the tab pairs are attached to a first layer of material which is then attached to a second layer of material on which an absorbent core is
Fung Paul
Menard Michael Joseph
Dixon Merrick
Johnson & Johnson Inc.
LandOfFree
Absorbent article with attached tabs and method and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Absorbent article with attached tabs and method and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absorbent article with attached tabs and method and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2465024