Stock material or miscellaneous articles – Structurally defined web or sheet – Including stitching and discrete fastener – coating or bond
Reexamination Certificate
1999-06-30
2002-10-15
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including stitching and discrete fastener, coating or bond
C428S195100, C428S198000, C442S328000, C442S381000, C442S394000
Reexamination Certificate
active
06465073
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to a stretchable nonwoven web or laminate material having bond lines to controllably reduce the stretchability of the web or laminate material in the machine direction and/or the cross-machine direction, and/or in different regions or zones of the material. In one embodiment, this invention is directed to a necked spunbond laminate material having zones or regions stretchable primarily in the machine direction and/or zones or regions stretchable primarily in the cross-machine direction. In another embodiment, the invention is directed to an elastomeric nonwoven web having controlled stretching in one or more directions and/or zones.
BACKGROUND OF THE INVENTION
Many types of elastic webs and processes by which these webs are made are well known in the art. These webs have been used in many personal care absorbent articles because the materials are capable of stretching in more than one direction due to the elasticity of the filaments. Also well known in the art are various types of composite elastic materials having at least one elastic sheet and at least one necked material joined to the elastic sheet, and the processes by which these composite materials are made. These composite elastic materials have also been used in many personal care absorbent articles.
Because the stretchability of the materials is not locally controllable, the materials do not have a predetermined stretch profile, or a predetermined variable stretch. Additionally, these materials do not have regions that stretch only in one direction and other regions in the material that stretch only in another, different direction.
It is often desirable when designing and making new stretchable products including diapers, garments, and workwear to have a material that: (a) has a predetermined stretch profile; (b) is stretchable only in one direction in one region of the material and stretchable only in a different direction in another region of the material; (c) is highly stretchable in one region of the material and stretchable to a lesser extent, but in the same direction, in another region of the material; or (d) exhibits properties of (a), (b) and/or (c) in combination.
SUMMARY OF THE INVENTION
This invention is directed to a stretchable nonwoven web or laminate material useful for personal care products, which has a predetermined and controlled stretch profile. Bond lines are applied in select regions of the material to reduce and, thereby, control the stretchability in directions parallel to the bond lines, in regions where the bond lines exist.
The stretchable nonwoven web of this invention may be a fibrous material such as, for example a spunbond web, a meltblown web, bonded carded web, or a combination thereof. The material may be made of an elastomeric fiber forming polymer. A meltblown web used in this invention may initially be produced using conventional meltblowing processes and apparatus as known in the art whereby a cohesive web is formed. A spunbond web used in this invention may initially be formed by techniques also well known in the art and described in U.S. Pat. No. 4,340,563 to Appel et al.; U.S. Pat. No. 3,692,618 to Dorschner et al.; and U.S. Pat. No. 3,802,817 to Matsuki et al.
A laminate material of this invention may include at least one elastic film or foam layer and a stretchable nonwoven web such as a necked nonwoven web. The nonwoven web is preferably a spunbond web, or a laminate which includes a spunbond web. The nonwoven web is stretched or elongated in a machine direction producing necking of the web in the cross-machine direction. While in an elongated or necked position, the web is bonded to an elastic sheet to form a nonwoven laminate material that is stretchable in a direction parallel to the direction of necking of the web, and which partly or fully recovers when the stretching force is removed. The necked nonwoven web is thermally bonded to the elastic film layer. Other bonding processes may also be used including, but not limited to, adhesive bonding and ultrasonic welding.
In accordance with this invention, bond lines are formed in one or more selected regions of the stretchable nonwoven web or laminate material in one or more selected directions, whereby the stretchability in the selected direction of the material can be controlled and substantially reduced in the region(s) of the bond lines. For example, a material with an initial stretch of about 200% in the cross-machine direction can be reduced to about 100% stretch with cross-machine direction bond lines that cover 50% of the material width.
A bonding strategy can be employed whereby the percentage of the material's area or width occupied by bond lines oriented in one direction is varied to produce a nonwoven web or laminate material which exhibits profiled stretching. This variable bonding can produce a range of elastic elongations in different regions of the same material. Also, the direction of the bond lines can be varied in different regions of the same material, causing different regions to have controlled stretchability in different directions.
In another embodiment of this invention, a stretchable spunbond elastic nonwoven web or necked spunbond laminate comprising an elastic film or foam layer and an elastic spunbond web is provided. The material is initially capable of stretching in the machine direction and in the cross-machine direction. Bond lines can be applied to the elastic nonwoven web or laminate material to produce a material having zoned stretching. Regions of the material contain zones in which bond lines are applied in a direction parallel to the cross-machine direction and zones in which bond lines are applied in a direction nonparallel (preferably perpendicular) to the cross-machine direction, i.e. in the machine direction.
A tensioning force applied in the cross-machine direction to the elastic nonwoven web or elastic laminate material will cause the regions which have bond lines with machine direction orientation to controllably stretch while regions which have bond lines with a cross-machine direction orientation will not stretch or exhibit reduced stretching. Conversely, when a tensioning force is applied in the machine direction to the elastic material, the regions which have bond lines with machine orientation will not stretch or exhibit reduced stretching, while the regions which have bond lines with a cross-machine orientation will controllably stretch. The stretchability of the material is easily controlled during the bond line application process, by varying the length, thickness and density or frequency of the bond lines.
With the foregoing in mind, it is a feature and advantage of the invention to provide a stretchable nonwoven web or laminate material having bond lines to reduce or control the stretchability of the material in one or more selected directions.
It is also a feature and advantage of this invention to provide a stretchable spunbond nonwoven web or laminate material having bond lines to reduce or control the stretchability of the material in the machine direction and/or the cross-machine direction.
It is also a feature and advantage of the invention to provide a nonwoven web or laminate material having a variable stretch profile, which is useful in a wide variety of stretchable products including diapers, other personal care products, workwear and other garments.
It is also a feature and advantage of the invention to provide a variable stretch nonwoven web or laminate material having regions with cross-machine direction stretch only and regions with machine direction stretch only.
The foregoing and other features and advantages of this invention will become further apparent from the following detailed description of the preferred embodiments, read in conjunction with the drawings.
REFERENCES:
patent: 3692618 (1972-09-01), Dorschner et al.
patent: 3802817 (1974-04-01), Matsuki et al.
patent: 3849241 (1974-11-01), Butin et al.
patent: 3949128 (1976-04-01), Ostermeier
patent: 4100324 (1978-07-01), Anderson et al.
pate
Morman Michael Tod
Odorzynski Thomas Walter
Zehner Georgia Lynn
Kimberly--Clark Worldwide, Inc.
Morris Terrel
Pauley Petersen Kinne & Erickson
Pratt Christopher C.
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