Patent Application
20060217022
The present invention relates generally to fastening systems and, in particular, to loop material for hook and loop fastening systems.
Hook and loop fastening systems are becoming prevalent in many durable and nondurable applications and are replacing other fastening devices such as tape, buckles, zippers and snaps. In general, hook and loop fastening systems include a male hook member, having a plurality of upstanding hook engaging elements, and a female loop member having a plurality of loops in which the hook members become ensnarled to effect fastening engagement of the two components.
Unfortunately, many of the hook and loop fastening systems available today can be difficult to manufacture or can have other drawbacks which may limit their utility. For example, woven and knit fabrics may require complex equipment and multiple processes in order to construct a loop material. Conventional nonwoven loop systems require inter-fiber bonding to reduce fiber spreading and accommodate hooks from a hook component. (e.g., see U.S. Pat. No. 5,326,612 to Goulait). Moreover, conventional loop member material may not be soft enough for personal hygiene applications, such as disposable diapers, surgical gowns, sanitary napkins, etc.
Applicants have discovered that spunlaced fabric having non-interbonded fibers (i.e., fibers not bonded to other fibers) can be produced that will engage hooks of hook and loop fastening systems with acceptable peel strength, as described in ASTM D-5170-98. A spunlaced fabric is a fabric which has been formed by impinging a web (which can include preformed fabrics, spunmelt webs, air laid webs and carded webs) with jets of high pressure water. Spunlaced fabrics have conventionally not been expected to offer any utility in the design of a loop material for a hook and loop fastening system. This is because the consolidation of fibers via water jets has been considered unsuitable for forming loops for use in hook and loop fastening systems. However, Applicants have unexpectedly discovered that a loop structure conducive to penetration and engagement by hook members can be created from spunlaced fabrics.
According to embodiments of the present invention, a method of forming a loop component for use in a hook and loop fastening system includes forming a spunlaced fabric having loop structures with no inter-fiber bonds, and bonding the spunlaced fabric to a backing layer to produce a loop component. Loop components according to embodiments of the present invention can have loop structures configured to engage hooks from a hook component having a hook density between about 30 and 400 hooks per square centimeter. Loop structures according to embodiments of the present invention can have a peel strength of between about 50 grams and 2000 grams, and can have a shear strength of between about 1,000 and 15,000 grams.
Embodiments of the present invention can provide aesthetically pleasing hook and loop fastening systems. Spunlaced loop member materials according to embodiments of the present invention are superior to conventional loop member materials because of the visual consistency and soft hand obtained. Moreover, loop members according to embodiments of the present invention have utility in a broad range of applications, particularly personal hygiene applications, such as disposable diapers, surgical gowns, sanitary napkins, etc.
The accompanying drawings, which form a part of the specification, illustrate embodiments of the present invention. The drawings and description together serve to fully explain the invention.
The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Referring now to
A loop component according to embodiments of the present invention can have loop structures configured to engage hooks from a hook component having a hook density between about 30 and 400 hooks per square centimeter. The loop structures can have a peel strength of between about 50 grams and 2000 grams (preferably 300-700 grams) using ASTM D5170-98, and can have peak shears of between about 1,000 and 15,000 grams (preferably 1,800-9,000 grams) using ASTM D5169-91.
Fibers within spunlaced fabrics, according to embodiments of the present invention, preferably have a denier of between about 0.5 and 19, and a density of between about 0.1 and 1.2 grams per cubic centimeter. However, embodiments of the present invention are not limited to fibers having this denier range or this density range. A spunlaced fabric according to embodiments of the present invention preferably has a thickness of between about 10 and 95 mils. However, embodiments of the present invention are not limited to spunlaced fabrics having this thickness range.
Well distributed and entangled fibers impart strength, consistency (visual coverage, uniform thickness and basis weight uniformity), smoothness and softness to spunlaced fabrics. The degree of fiber entanglement provided by water jet impingement can control the degree to which the fabric fuzzes after repeated peels from a hook member.
According to embodiments of the present invention, a batt of fibrous material may be formed above and below a spunbonded fabric or net. Fibers from the three layers may then be entangled via water jets (hydroentangling) to produce a spunlaced fabric.
The wet fibrous web of material may then be dried, for example using a vacuum box and a dryer (Block 120). If a finish and/or color is to be added to the spunlace fabric, a padder may be utilized, as is known to those skilled in the art. Another dryer immediately following the padder to dry the fibrous web may also be utilized. Additionally, the web can be apertured during the process.
The optional step of embossing a spunlaced fabric with a decorative pattern or other decorative indicia (Block 200) may provide additional dimensional stability to the spunlaced fabric.
An optional backing layer may provide additional dimensional stability, and may increase the durability of the structure to hook release forces and repeat engagements. A backing layer can also provide aesthetics by having various types of decorative indicia and/or colors. A backing layer may also help reduce “fuzzing” of a spunlaced fabric after repeated “peels” from a hook member, and may help reduce fiber “pull-out” from the spunlaced fabric.
Bonding the spunlaced fabric to a backing layer to produce a loop component (Block 300) may include bonding the spunlaced fabric to various types of materials. A composite backing layer and spunlaced fabric according to embodiments of the present invention may have a MD (machine direction) grab tensile strength of between about 10 pounds and 40 pounds. Moreover, a composite backing layer and spunlaced fabric according to embodiments of the present invention may have a Frazier air permeability of less than about 25 cubic feet per minute.
Bonding may be performed in one or more patterns. Bonding may be done using thermal or ultrasonic processes, autogenously, or may be attached using an adhesive, or using combinations of such techniques. The term “autogenously” means that the spunlaced fabric is secured to a backing layer without the aid of a third material. For example, spunlaced fabric can be fused or melted into a backing layer, and can be done so in a pattern. The bond area may be between about 2.5% and 25% of the surface area of the backing layer.
A backing layer may be a film, nonwoven fabric, lightweight woven fabric, or knit scrim. If the backing layer is a film it may be produced from a polymer such as polypropylene, polyester, polyolefin, polyvinyl alcohol, block copolymer, elastomeric polymer, copolyester, copolyether ester, urethane, styrene block copolymer, elastic foam, polyvinyl chloride, copolyether amide such as Pebax®, or combinations thereof. The most preferred polymer is a low-density polyethylene. Optionally, the film can be impervious to water. Film thickness may range from about 0.00025 inches to about 0.010 inches, with the most preferred range being from about 0.0006 inches to about 0.002 inches. The density of a backing layer film may be between about 0.65 grams per cubic centimeter and about 1.4 grams per cubic centimeter. Corona treatment of a backing layer film is optional for embodiments of the present invention.
For fabric backing layers, all of the nonwoven technologies such as spunbonded, thermal bonded, resin bonded, needle punched, stitch bonded, flash spun, spunlaced, wet-laid, thru-air bonded, and others known to those skilled in the art, would be appropriate. Paper, woven fabric, and knitted fabric could also be used.
Optionally, a fabric backing layer may be printed with a pattern, characters, and or other decorative indicia. A printed pattern and/or indicia may be used in addition to a pattern used in bonding.
Backing layers according to embodiments of the present invention preferably have a thickness of between about 0.4 and 40 mils, and a density of between about 0.65 and 1.4 grams per cubic centimeter. However, embodiments of the present invention are not limited to backing layers having this thickness range or this density range.
Hook and loop fastening systems according to embodiments of the present invention can be used as material for disposable diapers and other garments, and can be attached to the waist portion of disposable diapers and other garments utilizing techniques known to those skilled in the art. For example, embodiments of the present invention can be used as the waist band of a disposable diaper or other garment.
According to embodiments of the present invention, a hook and loop fastening system is provided that utilizes a female loop component as described above in conjunction with a male hook component of virtually any type. Preferably, a loop component has loop structures configured to engage hooks from a hook component having a hook density between about 30 and 400 hooks per square centimeter. Preferably, the loop structures have a peel strength of between about 50 grams and 2000 grams using ASTM D5170-98, and have peak shears of between about 1,000 and 15,000 grams using ASTM D5169-91. Exemplary hook components are available, for example, from Bender. Hook components may be formed from fibers of a wide range of materials. Suitable materials include, but are not limited to nylon, polyester, polypropylene, or any combination of these or other materials.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.
This application claims the benefit of U.S. Provisional Application No. 60/388,397, filed Jun. 12, 2002, the disclosure of which is incorporated herein by reference in its entirety as if set forth fully herein.
| Number | Date | Country | |
|---|---|---|---|
| 60388397 | Jun 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10266917 | Oct 2002 | US |
| Child | 11442901 | May 2006 | US |
