Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-12-23
2001-09-04
Aftergut, Jeff H. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S073100, C156S161000, C156S164000, C156S229000, C156S494000, C156S495000
Reexamination Certificate
active
06284081
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods and apparatus for applying an elastic material, particularly wide band elastic materials, in a curvilinear pattern on a continuously moving substrate. More particularly, the present invention relates to methods and apparatus for applying wide band elastic materials in curvilinear patterns on continuously moving substrates with severe enough angular displacement to produce a composite web structure, such as a disposable diaper or other absorbent article, with regions having the attached wide band elastic materials, such as leg cuff/containment flap regions, which are more “anatomically correct”.
BACKGROUND OF THE INVENTION
Conventional methods of making absorbent articles, such as disposable diapers, are well known in the art. These methods usually rely on attaching various elements to a continuously moving substrate, such as an absorbent article, as attachment materials. The elements may include leg cuffs, containment flaps or an element which is a combination leg cuff/containment flap, such as that shown in U.S. Pat. No. 5,827,387 issued Oct. 27, 1998, to Reynolds et al. The strip of attachment material may be applied to the continuously moving substrate in a discrete or continuous manner. One problem which has been encountered is the attachment of wide band elastic materials with severe enough angular displacement to provide for proper curvilinear placement. Specifically such curvilinear placement is desired to be “anatomically correct”, generally in the leg opening region of an absorbent article. Thus an absorbent article having this proper curvilinear placement is perceived as having a better fit on a body of a wearer of the absorbent article.
Curving the wide band elastic attachment material has been very difficult to accomplish and practice at high speed. Manufacturers have to settle for compromises, such as making disposable diapers having straight bands of elastic, minimal angular displacement of the elastic or reducing line speed.
The application of an elastic in a curvilinear pattern to a moving web generally requires the use of rollers for positioning the strip of elastic. U.S. Pat. No. 2,592,581 to Lorig discloses a method and apparatus for positioning a strip utilizing a roll which may be cylindrical, concave, or convex as desired to suit various installations. In U.S. Pat. No. 4,081,301 to Buell adhesive is intermittently applied to the elastic material while the elastic and web substrate are continuously run at high speed. Bourgeois, U.S. Pat. No. 3,828,367, discloses that a pair of elastic ribbons are fed to curved grooves in a roll under which a continuous web passes. As the roll with the ribbons in its grooves goes over the web, the ribbons are transferred in the contoured pattern of the grooves to the roll. One problem with a grooved roll is that it is unreliable and roping and C-folding occurs with wide band elastic ribbons. U.S. Pat No. 4,917,746 to Kons et al. discloses a method and apparatus involve a single roll moving or oscillating in a single dimension to apply each elastic ribbon to a web along an undulated path. U.S. Pat No. 4,915,767 to Rajala et al. uses a rotatable nip roll to press an elastic member against the web so the elastic member is spaced a predetermined maximum distance from a dwell line, a rotatable buffer roll above and in rolling engagement with the rotatable nip roll to cushion the rotatable nip roll against transient perturbations, and an oscillating roll, oscillating in a path transverse to a direction of web travel, above and spaced apart a predetermined length from the rotatable buffer roll. The oscillating roll applies the elastic member in a curved line on the rotatable buffer roll, with the predetermined maximum distance of the elastic member from the dwell line being directly proportional to the predetermined length between the oscillating roll and the rotatable buffer roll.
The method and apparatus of the present invention allows for high speed forming of continuously moving substrates having, as attached elements, elastic materials, such as wide band elastic materials, placed with severe angular displacement in a curvilinear pattern on a continuously moving substrate by allowing a caster roller to roll and pivot while placing the elastic materials either on a transfer roll or directly on a substrate.
SUMMARY
The present invention relates to apparatus and methods for applying at least one elastic material, in a curvilinear path, onto a continuously moving substrate.
The apparatus for applying at least one web of elastic material in a curvilinear path onto a continuously moving substrate has a transporting apparatus for continuously moving the substrate along a substrate path, a rotatable transfer roll, having a transfer roll axis adapted to be in rolling engagement with the substrate and to press the elastic material against the substrate along the curvilinear path, an oscillation unit having at least a first roll having a first roll axis, the first roll being mounted for rolling engagement with a surface of the transfer roll, the first roll also mounted for pivoting about a pivot axis transverse to the surface of said transfer roll and thus being effective to apply the elastic material to said transfer roll along the curvilinear path, the pivot axis lying in a plane perpendicular to and offset from the first roll axis such that the first roll can pivot while rolling, an elastic material supply for providing the elastic material to the first roll of said oscillation unit, an oscillating drive connected to said oscillation unit for oscillating said oscillation unit in a path generally transverse to the substrate path and a bonding apparatus to secure the elastic material to the substrate along the curvilinear path when the elastic material is pressed onto the substrate by the transfer roll. Optionally the transfer roll may be deleted and the first roll may directly contact the substrate to apply the elastic material in the curvilinear path.
The method applies at least one web of elastic material in a curvilinear path onto a continuously moving substrate by moving the substrate along the substrate path, supplying the elastic material to at least a first roll having a first roll axis, the first roll being mounted for rolling engagement with a surface of said transfer roll, and for pivoting about a pivot axis transverse to the surface of said transfer roll and thus being effective to apply the elastic material to said transfer roll along the curvilinear path, the pivot axis lying in a plane perpendicular to and offset from the first roll axis such that the first roll is operative to pivot while rolling, oscillating the oscillation unit in a path generally transverse to the substrate path applying the elastic material from the first roll to the transfer roll in a curvilinear path configuration, applying the elastic material, in the curvilinear path configuration, from the transfer roll to the substrate and bonding the elastic material, in the curvilinear path configuration, to the substrate. Optionally the transfer roll may be deleted and the first roll may directly contact the substrate to apply the elastic material in the curvilinear path configuration.
An additional method contemplates applying at least two elastic materials to a single transfer roll then applying the elastic materials from the transfer roll to the substrate and bonding the elastic materials to the substrate.
REFERENCES:
patent: 3828367 (1974-08-01), Bourgeois
patent: 4293367 (1981-10-01), Klasek et al.
patent: 4326528 (1982-04-01), Ryan et al.
patent: 4486192 (1984-12-01), Sigl
patent: 4617082 (1986-10-01), Oshefsky et al.
patent: 4726873 (1988-02-01), Ales et al.
patent: 4909870 (1990-03-01), Gould et al.
patent: 4915767 (1990-04-01), Rajala et al.
patent: 4917746 (1990-04-01), Kons et al.
patent: 5091039 (1992-02-01), Ujimoto et al.
patent: 5110403 (1992-05-01), Ehlert
patent: 5275676 (1994-01-01), Rooyakkers et al.
patent: 5525175 (1996-06-01), Blenke et al.
patent: 5560793 (1996-10-01),
Stopher James Bennington
Vogt Robert Eugene
Aftergut Jeff H.
Kimberly--Clark Worldwide, Inc.
Wilhelm Thomas D.
Wilhelm Law Service
Yee Paul Y.
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