US20070035058A1

US20070035058A1 - Method for relofting a nonwoven fiber batt

Info

Publication number: US20070035058A1
Application number: US11/175,422
Authority: US
Inventors: Steven Ogle; Kenneth Thompson
Original assignee: Individual
Current assignee: Polyester Fibers LLC
Priority date: 2005-07-06
Filing date: 2005-07-06
Publication date: 2007-02-15

Abstract

A method for relofting a nonwoven fiber product comprises forming a high-loft nonwoven fiber batt, compressing the high-loft nonwoven fiber batt to form a compressed fiber batt, securing the compressed fiber batt with a restraint, such that the compressed fiber batt will expand in the absence of the restraint, removing the restraint from the compressed fiber batt, thereby allowing the compressed fiber batt to expand into an expanded fiber batt, and relofting the expanded fiber batt using heat, thereby increasing the thickness of the expanded fiber batt to produce a relofted fiber batt. In an embodiment, the high-loft nonwoven fiber batt has a first thickness, the compressed fiber batt has a second thickness less than the first thickness, the expanded fiber batt has a third thickness greater than the second thickness, and the relofted fiber batt has a fourth thickness greater than the third thickness.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Manufacturers are constantly seeking new ways to reduce their production costs, which thereby decreases the price of their products and/or increases their profits. For nonwoven fiber batt manufacturers, production costs include shipping costs to transport their products to the customer. Fiber batt manufacturers generally transport their products by commercial freight carrier using a ship, train, aircraft, or truck, such as an 18-wheeler. Commercial freight carriers typically charge for their services by volume of product transported, such as by the trailer load. If the manufacturer could reduce the volume of each individual nonwoven fiber batt, then the quantity of nonwoven fiber batts that could be loaded into each trailer would increase, thereby reducing the per batt transportation cost. Thus, a need exists for a method of reducing the volume of a nonwoven fiber batt to thereby reduce transportation costs.
However, some methods of reducing the volume of a fiber batt tend to destroy the loft and resilient memory of the batt. For example, it is possible to compress a high-loft fiber batt until it becomes a densified fiber batt in which the air spaces therein are substantially reduced or eliminated. Doing so destroys the advantageous properties of loft and resilient memory inherent in the high-loft fiber batt such that the batt will not expand sufficiently when the compressive force is released. Accordingly, while such compression methods succeed in reducing volume, they are unsuitable for high-loft fiber batts. Therefore, a need exists for a method of reducing the volume of a high-loft fiber batt such that the loft and resilient memory of the fiber batt is not destroyed.
Another problem encountered when reducing the volume of high-loft fiber batts is that the uncompressed thickness of the fiber batt may be permanently decreased when the fiber batt has been compressed for an extended period of time. For example, a two-inch thick, high-loft nonwoven fiber batt that is compressed to one-inch thick and stored for an extended period of time may only expand to a thickness of one and three-quarters inches when the compressive force is removed. Although such a decrease in thickness appears marginal, in applications where there is a small tolerance for thickness variations, the decrease can render the fiber batt unsuitable for its intended purpose. One solution to this problem is to store uncompressed fiber batts or transport uncompressed fiber batts to the customers. However, for the reasons disclosed herein, it is not preferable to store or transport the fiber batt without first compressing it. Consequently, a need exists for a method of compressing a high-loft fiber batt for transportation and/or storage without destroying its loft and resilient memory. A need also exists for a method of returning the high-loft fiber batt to its original thickness after the compressive force has been released.

SUMMARY

In one aspect, the invention is a method for relofting a nonwoven fiber product, the method comprising: forming a high-loft nonwoven fiber batt; compressing the high-loft nonwoven fiber batt to form a compressed fiber batt; securing the compressed fiber batt with a restraint, such that the compressed fiber batt will expand in the absence of the restraint; removing the restraint from the compressed fiber batt, thereby allowing the compressed fiber batt to expand into an expanded fiber batt; and relofting the expanded fiber batt using heat, thereby increasing the thickness of the expanded fiber batt to produce a relofted fiber batt. In an embodiment, the high-loft nonwoven fiber batt has a first thickness; the compressed fiber batt has a second thickness less than the first thickness; the expanded fiber batt has a third thickness greater than the second thickness; and the relofted fiber batt has a fourth thickness greater than the third thickness. In embodiments the fourth thickness is greater than the first thickness, the high-loft nonwoven fiber batt is compressed without the use of heat, substantially all of the compression occurs in the thickness direction of the high-loft nonwoven fiber batt, and/or the third thickness in inches is greater than the weight per unit area in ounces per square foot of the expanded fiber batt. Variously, the restraint is a band that constricts the compressed fiber batt, the high-loft nonwoven fiber batt comprises a plurality of binder fibers and a plurality of carrier fibers, the binder fibers are sheath-core bicomponent fibers and the carrier fibers are polyester fibers, and/or a vacuum is used to compress the high-loft nonwoven fiber batt. The invention includes a nonwoven fiber product relofted according to the method.
In another aspect, the invention includes a method for relofting a nonwoven fiber product, the method comprising: forming a high-loft nonwoven fiber batt; compressing the high-loft nonwoven fiber batt without the use of heat, thereby forming a compressed fiber batt; securing the compressed fiber batt with a restraint, such that the compressed fiber batt will expand in the absence of the restraint; removing the restraint from the compressed fiber batt, thereby allowing the compressed fiber batt to expand into an expanded fiber batt; and relofting the expanded fiber batt using heat, thereby increasing the thickness of the expanded fiber batt to produce a relofted fiber batt. In an embodiment, substantially all of the compression occurs in the thickness direction of the high-loft nonwoven fiber batt. In another embodiment, the high-loft nonwoven fiber batt has a first thickness; the compressed fiber batt has a second thickness less than the first thickness; the expanded fiber batt has a third thickness greater than the second thickness; and the relofted fiber batt has a fourth thickness greater than the third thickness. Variously, the fourth thickness is greater than the first thickness, the restraint is a band that constricts the compressed fiber batt, the high-loft nonwoven fiber batt comprises a plurality of binder fibers and a plurality of carrier fibers, the binder fibers are sheath-core bicomponent fibers and the carrier fibers are polyester fibers, and/or a vacuum is used to compress the high-loft nonwoven fiber batt. The invention includes a nonwoven fiber product relofted according to the method.
In a third aspect, the invention is a method for relofting a nonwoven fiber product, the method comprising: forming a high-loft nonwoven fiber batt; compressing the fiber batt without the use of heat to form a compressed fiber batt, wherein substantially all of the compression occurs in the thickness direction of the fiber batt; expanding the compressed fiber batt into an expanded fiber batt; relofting the expanded fiber batt using heat, thereby increasing the thickness of the expanded fiber batt to produce a relofted fiber batt. In an embodiment, the method further comprises: securing the compressed fiber batt with a restraint, such that removal of the restraint expands the fiber batt; and removing the restraint from the compressed fiber batt, thereby producing the expanded fiber batt. In embodiments, the restraint is a band that constricts the compressed fiber batt and/or a vacuum is used to compress the fiber batt. In yet another embodiment, the high-loft nonwoven fiber batt has a first thickness; the compressed fiber batt has a second thickness less than the first thickness; the expanded fiber batt has a third thickness greater than the second thickness; and the relofted fiber batt has a fourth thickness greater than the third thickness. Variously, the fourth thickness is greater than the first thickness, the fiber batt comprises a plurality of binder fibers and a plurality of carrier fibers and/or the binder fibers are sheath-core bicomponent fibers and the carrier fibers are polyester fibers. The invention includes a nonwoven fiber product relofted according to the method.
In a fourth aspect, the invention is a method for relofting a nonwoven fiber product, the method comprising: forming a high-loft nonwoven fiber batt; compressing the high-loft nonwoven fiber batt to produce a compressed fiber batt, wherein substantially all of the compression occurs in the thickness direction of the fiber batt; securing the compressed fiber batt with a restraint, such that the compressed fiber batt will expand in the absence of the restraint; removing the restraint from the compressed fiber batt, thereby allowing the compressed fiber batt to expand into an expanded fiber batt; and relofting the expanded fiber batt using heat, thereby increasing the thickness of the expanded fiber batt to produce a relofted fiber batt. In embodiments, the restraint is a band that constricts the fiber batt, a vacuum is used to compress the high-loft nonwoven fiber batt, and/or the fiber batt is compressed without the use of heat. In another embodiment, the high-loft nonwoven fiber batt has a first thickness; the compressed fiber batt has a second thickness less than the first thickness; the expanded fiber batt has a third thickness greater than the second thickness; and the relofted fiber batt has a fourth thickness greater than the third thickness. Variously, the fourth thickness is greater than the first thickness, the high-loft nonwoven fiber batt comprises a plurality of binder fibers and a plurality of carrier fibers, and/or the binder fibers are sheath-core bicomponent fibers and the carrier fibers are polyester fibers. The invention includes a nonwoven fiber product relofted according to the method.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and for further details and advantages thereof, reference is now made to the accompanying drawings, in which:
FIG. 1 is a block diagram showing the Method for Relofting a Nonwoven Fiber Batt;
FIG. 2 is a plan view of an embodiment of an apparatus for forming a nonwoven fiber batt in accordance with the method of FIG. 1;
FIG. 3A is a side view of an embodiment of a thermal bonding apparatus used in forming a nonwoven fiber batt in accordance with the method of FIG. 1;
FIG. 3B is a side view of an alternative embodiment of a thermal bonding apparatus used in forming a nonwoven fiber batt in accordance with the method of FIG. 1;
FIG. 4A is a side view of an embodiment of an apparatus for compressing and securing a nonwoven fiber batt in accordance with the method of FIG. 1;
FIG. 4B is a perspective view of an alternative embodiment of an apparatus for compressing and securing a nonwoven fiber batt in accordance with the method of FIG. 1;
FIG. 5A is a side view of an embodiment of an apparatus for removing the restraint from a compressed nonwoven fiber batt in accordance with the method of FIG. 1;
FIG. 5B is a perspective view of an alternative embodiment of an apparatus for removing the restraint from a compressed nonwoven fiber batt in accordance with the method of FIG. 1; and
FIG. 6 is a side view of an embodiment of an apparatus for relofting the nonwoven fiber batt in accordance with the method of FIG. 1.

DETAILED DESCRIPTION

As depicted in FIG. 1, in general, one method 70 for relofting a nonwoven fiber batt comprises: forming a nonwoven fiber batt at step 72, compressing the fiber batt at step 74, securing the fiber batt in its compressed state with a restraint at step 76, transporting the fiber batt at step 78, removing the restraint to expand the compressed fiber batt at step 80, and optionally relofting the fiber batt at step 82.
In more detail, the method 70 generally commences by forming a nonwoven fiber batt per step 72 of method 70. It will be well recognized that the methods disclosed herein are not limited to the specific composition of the nonwoven fiber batt. However, for purposes of illustration, the nonwoven fiber batt may comprise a homogeneous blend of binder fibers and carrier fibers. The binder fibers and the carrier fibers may be either natural fibers or synthetic fibers. For example, thermoplastic polymer fibers such as polyester or polypropylene are suitable synthetic carrier fibers. Wool, cotton, and silk are examples of suitable natural carrier fibers. Other fibers can be used depending upon the precise processing limitations imposed and the desired characteristics of the nonwoven batt. For purposes of illustrating the formation of a nonwoven fiber batt, and not by way of limitation, the carrier fibers may be KoSa Type 209, 6 to 15 denier, 2 to 3 inches in length, round, hollow, cross-section polyester fibers. Alternatively, the carrier fibers may be KoSa Type 295, 6 to 15 denier, ⅕ to 4 inches in length, pentalobal, cross-section polyester fibers. As one of the ordinary skill in the art will readily recognize, other nonwoven fibers are suitable as carrier fibers for the present invention and are within the scope of this invention.
Binder fibers have a relatively low predetermined melting temperature as compared to carrier fibers. As used herein, however, the term melting as applied to solid polyester binder fibers does not necessarily refer only to the actual transformation of the binder fibers into liquid form. Rather, it includes a gradual transformation of the fibers over a range of temperatures wherein the fiber becomes sufficiently soft and tacky to cling to other fibers, including other binder fibers with the same characteristics and adjacent carrier fibers having a higher melting temperature. In the case of bicomponent sheath/core fibers, the term melting includes gradual transformation of the fiber sheaths over a range of temperatures within which the sheaths become sufficiently soft and tacky to cling to other fibers, including other bicomponent sheath/core fibers with the same characteristics and adjacent carrier fibers having a higher melting temperature. It is an inherent characteristic of thermoplastic fibers, such as polyester, that they become sticky and tacky when melted, as that term is used herein. For purposes of illustrating one embodiment of a nonwoven fiber batt, and not by way of limitation, the binder fibers may be KoSa Type 254 Celbond®, which is a bicomponent fiber with a polyester core and a copolyester sheath having a melting temperature of approximately 230° F. (110°C.). The binder fiber, alternatively, may be a polyester copolymer, for example, rather than a bicomponent fiber.
While the homogeneous mixture of carrier fibers and binder fibers can be any of a number of suitable fiber blends, for purposes of illustrating the process and first blend, the mixture comprises binder fibers in an amount sufficient for binding the fibers of the blend together upon application of heat at the appropriate temperature to melt the binder fibers. In one example, the binder fibers comprise about 5 percent to about 100 percent by total volume of the blend. In one embodiment, the binder fibers are present in the range of about 10 percent to about 15 percent for a high-loft batt, and in the range of about 15 percent to about 40 percent for a densified batt, as those characteristics are discussed below. The carrier fibers comprise about 0 percent to about 95 percent by total volume of the blend. In one embodiment, the carrier fibers are present in the range of about 85 percent to about 90 percent for a high-loft batt, and in the range of about 60 percent to about 85 percent for a densified batt, as those characteristics are discussed below. Blends having other percentages of binder fibers and carrier fibers are also within the scope of the invention.
It will be well recognized that the Method for Relofting a Nonwoven Fiber Batt is not limited to any specific method of forming the nonwoven fiber batt. However, for purposes of illustration, FIG. 2 depicts a schematic top plan view of a general processing line 110 for forming a nonwoven fiber batt in accordance with step 72 of FIG. 1, and in accordance with the teachings of the present invention. The carrier fibers and binder fibers are blended together in a fiber blender 112 to form a fiber blend. In one embodiment, the fiber blend comprises carrier fibers, such as polyester, and binder fibers, such as sheath-core bicomponent fibers, but the fiber blend may comprise a blend of any binder fibers and any carrier fibers. The fiber blend is conveyed by conveyor pipes 114 to a web-forming machine, or, in this example, three machines 116, 117 and 118. A suitable web-forming machine is a Garnett machine, for example. An air laying machine, known in the trade as a Rando webber, or any other suitable apparatus can also be used to form a web structure.
Garnett machines 116, 117, and 118 card the blended fibers into a web and deliver the web to cross-lappers 116′, 117′, and 118′ to cross-lap the web onto a slat conveyor 120, which is moving in the machine direction. Cross-lappers 116′, 117′, and 118′ reciprocate back and forth in the cross direction from one side of conveyor 120 to the other side to form a web 100 having multiple thicknesses in a progressive overlapping relationship. The number of layers that make up the web 100 is determined by the speed of the conveyor 120 in relation to the speed at which successive layers of the web 100 are layered on top of each other and the number of cross-lappers 116′, 117′, and 118′. Thus, the number of single layers that make up the web 100 can be increased by slowing the relative speed of the conveyor 120 in relation to the speed at which cross layers are layered, by increasing the number of cross-lappers 116′, 117′, and 118′, or both. Conversely, a fewer number of single layers can be achieved by increasing the relative speed of conveyor 120 to the speed of laying the cross layers, by decreasing the number of cross-lappers 116′, 117′, and 118′, or both. In the present invention, the number of single layers making up the web 100 of fibers will vary depending upon the desired characteristics of the nonwoven fiber batt. As a result, the relative speed of the conveyor 120 to the speed at which cross layers are layered, and the number of cross-lappers 116′, 117′, and 118′ for forming the web 100 may vary accordingly.
The conveyor 120 then transports the web 100 to housing 130 for mechanical and/or vacuum compression and heating. While there are a variety of thermal bonding methods suitable for the purposes contemplated herein, one such method is the application of vacuum pressure through perforations (not shown) in first and second counter rotating drums 140, 142 positioned in a central portion of the housing 130. The first and second counter rotating drums 140, 142 heat the web 100 to the extent necessary to melt the binder fibers in the web 100. For example, heating the web 100 to a temperature of approximately 225-275° F. for a period of three to five minutes is suitable for the purposes contemplated herein. Alternatively, the web 100 may instead move through an oven by substantially parallel perforated or mesh wire aprons that mechanically compress the batt and simultaneously melt the binder fibers, as will be discussed in more detail herein.
As the web 100 exits the housing 130, the web 100 is compressed and cooled using a pair of substantially parallel wire mesh aprons 170, only one of which is visible in FIG. 2. The aprons 170 are mounted for parallel movement relative to each other to facilitate adjustment for a wide range of web thicknesses. The web 100 can be cooled slowly via exposure to ambient temperature air or, in the alternative, ambient temperature air can be forced through the perforations of one apron 170, through the web 100 and through the perforations of another apron 172 (shown in FIG. 3A) to cool the web 100 and set it in a compressed state. The web 100 is maintained in compressed form upon cooling because the binder fibers solidify to bond the fiber blend together in that state.
While there are a variety of thermal bonding methods that are suitable for the present invention, one such method, illustrated in FIG. 2 and FIG. 3A, comprises holding the web 100 by vacuum pressure applied through perforations of first and second counter-rotating drums 140, 142 and heating the web 100 so that binder fibers in the batt melt to the extent necessary to fuse together the fiber blend in the web 100.
As depicted in FIG. 3A, the vacuum pressure method may be implemented using counter-rotating drums 140, 142 having perforations 141, 143 therein, respectively, which are positioned in a central portion of the housing 130. The housing 130 also comprises an air circulation chamber 132 and a furnace 134 in an upper portion and a lower portion, respectively. One drum 140 is positioned adjacent an inlet 144 though which the web 100 is fed. The web 100 is delivered from the blending and web-forming processes described with respect of FIG. 1 by means of an infeed apron 146. A suction fan 150 is positioned in communication with the interior of the drum 140. The lower portion of the circumference of the drum 140 is shielded by a baffle 151 positioned inside the drum 140 such that the suction-creating air flow is forced to enter the drum 140 through the perforations 141, which are proximate the upper portion of the drum 140, as the drum 140 rotates.
Another drum 142 is positioned downstream from the first drum 140 in the housing 130. The drums 140, 142 can also be mounted for lateral sliding movement relative to one another to facilitate adjustment for a wide range of batt thicknesses (not shown). The second drum 142 includes a suction fan 152 that is positioned in communication with the interior of the drum 142. The upper portion of the circumference of the drum 142 is shielded by a baffle 153 positioned inside the drum 142 so that the suction-creating air flow is forced to enter the drum 142 through the perforations 143, which are proximate the lower portion of drum 142, as the drum 142 rotates.
Thus, the nonwoven web 100 is held in vacuum pressure as it moves from the upper portion of the rotating drum 140 to the lower portion of the counter rotating drum 142. The furnace 134 heats the air in the housing 130 as it flows from the perforations 141, 143 to the interior of the drums 140, 142, respectively, to melt the binder fibers in the web to the extent necessary to bind the fiber blend in the web together.
Referring now to FIG. 3B, in an alternative thermal bonding process, the web 100 enters a housing 130′ by a pair of substantially parallel perforated or mesh wire aprons 160, 162. The housing 130′ comprises an oven 134′ that heats the web 100 to melt the binder fibers to the extent necessary to bind the fiber blend in the web 100 together.
Collectively referring again to FIGS. 2, 3A and 3B, the web 100 is compressed and cooled as it exits the housing 130 or housing 130′ by a pair of substantially parallel first and second perforated or wire mesh aprons 170, 172 of FIG. 3A or 160, 162 of FIG. 3B. The aprons 170, 172 or 160, 162 are mounted for parallel movement relative to each other to facilitate adjustment for a wide range of web thicknesses (not shown). The web 100 can be cooled slowly through exposure to ambient temperature air or, alternatively, ambient temperature air can be forced through the perforations of one apron, through the web 100 and through the perforations of the other apron to cool the web 100 and set it in a compressed state. The web 100 is maintained in a compressed form upon cooling since the binder fibers are solidified during cooling to bond the fiber blend of the web 100 together in its compressed state. After bonding, compression and cooling, the cooled web is referred to as a batt 122. Referring to FIG. 2, the fiber batt 122 then moves into a cutting zone 180 where the lateral edges of the batt 122 are trimmed. The fiber batt 122 is also cut transversely to a desired length.
In alternative embodiments of the method, it is contemplated that other bonding methods, such as mechanical bonding and resin bonding, may be used to bond the fiber batt 122 together in lieu of the thermal bonding methods described herein. Mechanical bonding is the process of bonding the nonwoven batt 122 together without the use of resins, binder fibers, adhesives, or heat. Examples of mechanical bonding methods include needle punching and hydro entanglement. Needle punching is the process of entangling the fibers in the web together using barbed needles. Hydro entanglement uses streams of high pressure water to entangle the fibers of the nonwoven web. Resin bonding is a process by which the carrier fibers are coated in adhesive resin. Once it is cured in an oven, the adhesive resin bonds the carrier fibers together, thereby accomplishing the same task as the binder fibers. For resin bonded batts, resin is generally used in lieu of the binder fibers in the nonwoven batt. It will be readily apparent to one of ordinary skill in the art that the Method for Relofting a Nonwoven Fiber Batt includes nonwoven production methods other than those described herein, and should not be limited thereto.
In one embodiment of the nonwoven fiber batt 122, the weight, density, and thickness of the nonwoven fiber batt 122 are determined by, among other factors, the process of compressing the batt 122 during cooling, as discussed in more detail below. The ratio of batt density to batt thickness generally dictates whether the nonwoven fiber batt is a high-loft batt or a densified batt. For purposes of description herein, a densified batt has a weight (in ounces per square foot) greater than its thickness (in inches). Thus, a densified fiber batt generally has a density greater than about 0.75 pounds per cubic foot (pcf). Conversely, a high-loft fiber batt has a weight (in ounces per square foot) less than its thickness (in inches) and/or a density less than about 0.75 pcf. High-loft batts also generally have at least about 90 percent air by volume and a thickness of at least about 3 millimeters.
After the fiber batt 122 is formed per step 72, the fiber batt 122 is compressed per step 74 of method 70 depicted in FIG. 1. FIG. 4A depicts one embodiment of an apparatus 220 used to compress the fiber batt 122. The fiber batt 122 shown in FIG. 4A may be a single fiber batt 122 or a plurality of fiber batts 122 laminated atop of one another. As shown in phantom in FIG. 4A, absent a compressive force, the fiber batt 122 has a first thickness, T₁. However, when the fiber batt 122 is placed between a lower plate 224 and an upper plate 226 and a compressive force is applied that causes a plunger 228 to move the upper plate 226 towards the lower plate 224, the apparatus 220 compresses the fiber batt 122 to a second thickness T₂that is less than the first thickness T₁. The apparatus 220 may be adapted to compress the fiber batt 122 only in the thickness direction (z-direction), without substantially expanding or compressing the fiber batt 122 in the cross-direction (x-direction) or the machine direction (y-direction). The apparatus 220 compresses the fiber batt 122 so as to substantially reduce the spaces in the fiber batt 122; however, the apparatus 220 does not compress the fiber batt 122 so much that the resilient memory inherent in the fiber batt 122 is substantially altered or destroyed. In other words, the apparatus 220 only compresses the fiber batt 122 such that the fiber batt 122 will expand if the compressive force is released, but not to the point where the fiber batt 122 is permanently positioned in its compressed state. In one embodiment, the apparatus 220 does not utilize heat to compress the fiber batt 122. However, in other embodiments, heat may be used to assist in compressing the fiber batt 122 so long as the heat does not substantially alter or destroy the resilient memory inherent in the fiber batt 122.
In an alternative embodiment, of the apparatus 220 of FIG. 4A, a vacuum source (not shown) may be connected to a plurality of apertures (not shown) in the lower plate 224 such that air is passed through the upper and side surfaces of the fiber batt 122 and into the apertures, thereby compressing the fiber batt 122. This vacuum embodiment may be used in lieu of the upper plate 226 of FIG. 4A to compress the fiber batt 122. This vacuum embodiment may also be used in conjunction with the apparatus 220 shown in FIG. 4A to compress the fiber batt 122.
FIG. 4B illustrates an alternative method for compressing the fiber batt per step 74 of method 70. FIG. 4B depicts an embodiment of an apparatus 220′ that compresses the fiber batt 122 between an upper roller 226′ and a lower roller 224′, then rolls the compressed fiber batt 122 onto the upper roller 226′. The fiber batt 122 shown in FIG. 4B may be a single fiber batt 122 or a plurality of fiber batts 122 laminated atop of one another. When the fiber batt 122 passes between the upper roller 226′ and the lower roller 224′, a force is applied that causes the plungers 228′ to press the upper roller 226′ against the lower roller 224′, thereby compressing the fiber batt 122 from the first thickness, T₁to the second thickness, T₂. As the fiber batt 122 is compressed, it is wound onto the upper roller 226′, which rotates at the same rate as the fiber batt 122 is fed into the apparatus 220′. In addition, the compressive force applied to the plungers 228′ is controlled such that, as the diameter of the roll of compressed fiber batt 122 increases, the upper roller 226′ is raised, thereby keeping a consistent amount of compression on the thickness of the entire length of the fiber batt 122. Using this compressive procedure, the apparatus 220′ only compresses the fiber batt 122 in the thickness direction (z-direction) and does not substantially expand or compress the fiber batt 122 in the cross-direction (x-direction) or the machine direction (y-direction).
The apparatus 220′ compresses the fiber batt 122 so as to substantially eliminate most of the air spaces in the fiber batt 122; however, the apparatus 220′ does not compress the fiber batt 122 so much that the resilient memory inherent in the fiber batt 122 is substantially altered or destroyed. In other words, the apparatus 220′ only compresses the fiber batt 122 such that the fiber batt 122 will expand if the compressive force is released, but not to the point where the fiber batt 122 is permanently positioned in its compressed state. In one embodiment, the apparatus 220′ does not utilize heat to compress the fiber batt 122. However, in other embodiments, heat may be used to assist in compressing the fiber batt 122 so long as the heat does not substantially alter or destroy the resilient memory inherent in the fiber batt 122.
In an alternative embodiment, of the apparatus of 220′ of FIG. 4B, a vacuum source (not shown) may be connected to a plurality of apertures (not shown) in the upper roller 226′ such that air is passed through the outside and ends of the rolled fiber batt 122 and into the apertures, thereby compressing the fiber batt 122 on the upper roller 226′. This vacuum embodiment may be used in lieu of the lower roller 224′ of FIG. 4B to compress the fiber batt 122. This vacuum embodiment may also be used in conjunction with the apparatus 220′ shown in FIG. 4B to compress the fiber batt 122. It will be readily apparent to one of ordinary skill in the art that the Method for Relofting a Nonwoven Fiber Batt also includes compression methods other than those described herein and should not be limited thereto.
Returning again to FIG. 4A, after it is compressed, the fiber batt 122 is secured in its compressed state with a restraint per step 76 of method 70 shown in FIG. 1. The upper plate 226 and the lower plate 224 illustrated in FIG. 4A contain a plurality of notches 230 that allow a user to wrap a restraint 232, such as a band or strap, around the fiber batt 122 while the fiber batt 122 is in its compressed state. Specifically, the user may position the restraint 232 around the compressed fiber batt 122 and fasten the restraint 232 to itself or to the fiber batt 122 using any means generally known within the art, such as adhesives, staples, brads, rivets, or the like. Alternatively, a thin polymeric film shrink wrap (not shown) may be wrapped around the compressed fiber batt 122 to secure the fiber batt 122 in its compressed state.
FIG. 4B illustrates an alternative method for securing the fiber batt 122 in its compressed state with a restraint per step 76 of method 70 shown in FIG. 1. The lower roller 224′ illustrated in FIG. 4B contains a plurality of notches 230′ that allow a user to wrap a restraint 232, such as a band or strap, around the fiber batt 122 while the fiber batt 122 is in its compressed state. Specifically, the user may position the restraint 232 around the compressed fiber batt 122 and fasten the restraint 232 to itself or to the fiber batt 122 using any means generally known within the art, such as adhesive, staples, brads, rivets, or the like. Alternatively, a thin polymeric film shrink wrap (not shown) may be wrapped around the compressed fiber batt 122 to secure the fiber batt 122 in its compressed state. It will be readily apparent to one of ordinary skill in the art that the Method for Relofting a Nonwoven Fiber Batt includes securing methods other than those described herein and should not be limited thereto.
After the fiber batt 122 has been secured per step 76 of method 70 shown in FIG. 1, the fiber batt is transported from a first location to a second location per step 78 of method 70. In one embodiment, the first location is the manufacturing facility that forms the fiber batt 122 and the second location is a separate relofting facility located apart from the manufacturing facility. In one embodiment, the method of transporting the compressed fiber batt 122 from the first location to the second location comprises loading the compressed fiber batt 122 into the trailer of a commercial freight carrier, such as a ship, a train, an aircraft, or an 18-wheeler truck, for example. Commercial freight carriers typically charge by the trailer load, subject to certain weight restrictions. Because the weight restriction is large compared to the volume capacity of a trailer, fiber batt manufacturers are essentially charged by the trailer load. Reducing the volume of each individual nonwoven fiber batt allows for a greater quantity of fiber batts 122 to be loaded into the trailer, thus reducing the individual transportation (shipping) cost associated with each individual fiber batt 122. Consequently, the process described in method 70 is particularly advantageous in that it allows fiber batt manufacturers to compress the fiber batts 122 so as to reduce their per batt transportation costs, while still retaining the resilient memory of the fiber batt 122.
In an alternative embodiment, the fiber batt 122 is transported from a first location to a second location, wherein the first location is the manufacturing facility that forms the fiber batt 122 and the second location is a storage facility, either within the manufacturing facility or separate from the manufacturing facility. Manufacturing facilities often include storage facilities so that inventory may be stored for customers. Manufacturing facilities generally own their storage facilities or lease their storage facilities from a third party. In either case, the storage volume is finite and the manufacturing facility incurs additional costs associated with such storage space. By utilizing the aforementioned steps 72, 74, and 76 of method 70, the manufacturing facility may store more fiber batts 122 in the storage facility than was previously possible. In some cases, where the manufacturing facility leases or rents the storage facility, the manufacturing facility may reduce its overall storage costs by utilizing all or part of method 70. It will be readily apparent to one of ordinary skill in the art that the Method for Relofting a Nonwoven Fiber Batt includes transportation methods other than those described herein and should not be limited thereto.
After the fiber batt 122 has been transported, the restraints 232 may be removed from the compressed fiber batt 122 per step 80 of method 70 depicted in FIG. 1. FIGS. 5A and 5B show the restraints 232 being removed from the compressed fiber batt 122 by a knife 240. In FIG. 5A, the fiber batt 122 is shown expanding from its compressed thickness, T₂(shown partially in phantom in FIG. 5A), to an expanded thickness, T₃, which is greater than T₂. In FIG. 5B, the rolled fiber batt 122 is shown expanding and/or unraveling when the restraints 232 are removed. The original size of the rolled fiber batt 122 is shown in phantom in FIG. 5B. In either case, the fiber batt 122 expands to the expanded thickness T₃because the fiber batt 122 still retains some or all of its resilient memory. If the fiber batt 122 retains substantially all of its resilient memory, the expanded thickness T₃will be substantially the same as the original fiber batt thickness T₁. If the fiber batt 122 retains only a portion of its resilient memory, the expanded thickness T₃will be less than the original fiber batt thickness T₁. Regardless of the extent of expansion of the fiber batt 122, it is contemplated that the batt 122 will expand enough to be suitable for use in applications requiring a high-loft fiber batt 122. It will be readily apparent to one of ordinary skill in the art that the Method for Relofting a Nonwoven Fiber Batt includes restraint removal methods other than those described herein and should not be limited thereto.
After the restraints 232 are removed, the fiber batt 122 may optionally be relofted per step 82 of method 70 depicted in FIG. 1. Relofting is a process wherein the thickness of the fiber batt 122 is increased by heating the fiber batt 122 in a relofting apparatus, one embodiment of which is shown in FIG. 6. As shown in FIG. 6, the fiber batt 122 enters a relofting apparatus 250 where the fiber batt 122 is supported by a moving conveyor 254. A heating source (not shown), such as an oven, burner, or infrared lamp, in the relofting apparatus 250 produces heat 252 that passes through holes (not shown) in the conveyor 254 to increase the temperature of the fiber batt 122. As the temperature increases, the binder fibers within the fiber batt 122 begin to soften, and some of the binder fibers and/or carrier fibers begin to realign with, and/or detach from, the softened binder fibers. The realigning and/or detaching binder and/or carrier fibers cause the fiber batt 122 to increase in thickness, thereby decreasing the density of the fiber batt 122.
As depicted in FIG. 6, the fiber batt 122 enters the relofting apparatus 250 at the unrestrained, expanded thickness T₃. However, as the relofting apparatus 250 heats the fiber batt 122, its thickness increases to a relofted thickness T₄, which is greater than T₃. The final relofted thickness T₄is dependent upon the temperature within the relofting apparatus 250 and the residence time, which is the overall time that the fiber batt 122 is exposed to the increased temperature within the relofting apparatus 250. In one embodiment, a temperature of approximately 180° F. is sufficient to reloft the binder fibers as described herein. In another embodiment, the temperature and the residence time may be similar to the temperature and residence time in the housing 130 shown in FIG. 2: i.e. approximately 225-275° F. for three to five minutes. Higher or lower temperatures and/or residence time may be selected depending upon the desired relofted thickness T₄of the fiber batt 122. Further, depending on the selected temperature and the residence time, the relofted thickness T₄may be greater than or less than the original fiber batt thickness T₁. Generally, a greater residence time and/or a higher temperature within the relofting apparatus 250 will tend to create a fiber batt 122 having a relofted thickness T₄greater than the original fiber batt thickness T₁. Alternatively, a lesser residence time and/or a lower temperature within the relofting apparatus 250 will tend to create a fiber batt 122 having a relofted thickness T₄greater than the expanding thickness T₃, but less than the original fiber batt thickness T₁. As will be readily apparent to one of ordinary skill in the art, the Method for Relofting a Nonwoven Fiber Batt includes relofting methods other than those described herein and should not be limited thereto.
an alternative embodiment, the relofting step 82 of method 70 may be combined with a quilting process. In particular, the fiber batt 122 may be laminated onto a quilt backing after the restraints 232 are removed from the compressed fiber batt 122, as described above. The lamination is then fed into a quilting/relofting apparatus that relofts the fiber batt 122 per step 82 and also quilts the fiber batt 122 to the quilt backing. One of ordinary skill in the art will appreciate that the quilting/relofting apparatus may be a single machine or may be a plurality of separate machines. In addition, a person of ordinary skill in the art will appreciate that the quilting/relofting apparatus may contemporaneously or consecutively reloft and quilt the lamination. If the quilting/relofting apparatus quilts and relofts the lamination consecutively, the quilting and relofting processes may be performed in either order. It will also be well appreciated by a person of ordinary skill in the art that the fiber batt 122 may be laminated onto a quilt backing prior to compression. In such an embodiment, other layers of material, such as polymeric foam or other densified or high-loft nonwoven or woven fiber batts, for example, may be laminated onto the fiber batt 122 and the quilt backing prior to compressing the lamination. If additional layers are laminated onto the fiber batt 122, the lamination may be compressed, restrained, and transported as described above. The restraints may then be removed from the lamination, and the lamination relofted and quilted as described above.
The nonwoven fiber batt 122 manufactured according to the Method for Relofting a Nonwoven Fiber Batt described herein is suitable for a variety of applications. The fiber batt 122 may be used, for example, to manufacture articles of furniture, including chairs, sofas, loveseats, ottomans, beds, and so forth. Moreover, the fiber batt 122 may be used for automobile, airplane, or other vehicle upholstery. The fiber batt may also be used in mattresses, quilts, pillows, comforters, bedding, and other household articles. The Method for Relofting a Nonwoven Fiber Batt also includes other applications not specifically listed, and the scope of the invention should not be restricted to the aforementioned applications.
While a number of preferred embodiments of the invention have been shown and described herein, modifications thereof may be made by one skilled in the art without departing from the spirit and the teachings of the invention. The embodiments described herein are exemplery only and are not intended to be limiting. Many variations, combinations, and modifications of the invention disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims.

Claims

1. A method for relofting a nonwoven fiber product, the method comprising:

forming a high-loft nonwoven fiber batt;

compressing the high-loft nonwoven fiber batt to form a compressed fiber batt;

securing the compressed fiber batt with a restraint, such that the compressed fiber batt will expand in the absence of the restraint;

removing the restraint from the compressed fiber batt, thereby allowing the compressed fiber batt to expand into an expanded fiber batt; and

relofting the expanded fiber batt using heat, thereby increasing the thickness of the expanded fiber batt to produce a relofted fiber batt.

2. The method of claim 1:

wherein the high-loft nonwoven fiber batt has a first thickness;

wherein the compressed fiber batt has a second thickness less than the first thickness;

wherein the expanded fiber batt has a third thickness greater than the second thickness; and

wherein the relofted fiber batt has a fourth thickness greater than the third thickness.

3. The method of claim 2 wherein the fourth thickness is greater than the first thickness.

4. The method of claim 3 wherein the high-loft nonwoven fiber batt is compressed without the use of heat.

5. The method of claim 4 wherein substantially all of the compression occurs in the thickness direction of the high-loft nonwoven fiber batt.

6. The method of claim 5 wherein the third thickness in inches is greater than the weight per unit area in ounces per square foot of the expanded fiber batt.

7. The method of claim 1 wherein the restraint is a band that constricts the compressed fiber batt.

8. The method of claim 1 wherein the high-loft nonwoven fiber batt comprises a plurality of binder fibers and a plurality of carrier fibers.

9. The method of claim 8 wherein the binder fibers are sheath-core bicomponent fibers and the carrier fibers are polyester fibers.

10. The method of claim 1 wherein a vacuum is used to compress the high-loft nonwoven fiber batt.

11. A nonwoven fiber product relofted according to the method of claim 1.

12. A method for relofting a nonwoven fiber product, the method comprising:

forming a high-loft nonwoven fiber batt;

compressing the high-loft nonwoven fiber batt without the use of heat, thereby forming a compressed fiber batt;

13. The method of claim 12 wherein substantially all of the compression occurs in the thickness direction of the high-loft nonwoven fiber batt.

14. The method of claim 13:

wherein the high-loft nonwoven fiber batt has a first thickness;

15. The method of claim 14 wherein the fourth thickness is greater than the first thickness.

16. A method for relofting a nonwoven fiber product, the method comprising:

forming a high-loft nonwoven fiber batt;

compressing the fiber batt without the use of heat to form a compressed fiber batt, wherein substantially all of the compression occurs in the thickness direction of the fiber batt;

expanding the compressed fiber batt into an expanded fiber batt;

17. The method of claim 16 further comprising:

securing the compressed fiber batt with a restraint, such that removal of the restraint expands the fiber batt; and

removing the restraint from the compressed fiber batt, thereby producing the expanded fiber batt.

18. The method of claim 16 wherein a vacuum is used to compress the fiber batt.

19. The method of claim 16:

wherein the high-loft nonwoven fiber batt has a first thickness;

20. The method of claim 19 wherein the fourth thickness is greater than the first thickness.