Patent application title: PROCESS FOR MAKING BAMBOO FIBERFILL AND ARTICLES THEREOF
Jordan Bradley Young (Ridgefield, CT, US)
Fairfield Processing Corp.
IPC8 Class: AD01B110FI
Class name: Paper making and fiber liberation processes of chemical liberation, recovery or purification of natural cellulose or fibrous material with decortication or mechanical preparation of textile fibers
Publication date: 2009-04-23
Patent application number: 20090101294
Patent application title: PROCESS FOR MAKING BAMBOO FIBERFILL AND ARTICLES THEREOF
Jordan Bradley Young
CANTOR COLBURN, LLP
Fairfield Processing Corp.
Origin: HARTFORD, CT US
IPC8 Class: AD01B110FI
A process for producing bamboo fiberfill from raw bamboo fiber includes,
obtaining a bale of the raw bamboo fiber, picking up and separating the
raw bamboo bale fiber into tufts of bamboo fiber with a bale opener,
feeding the bamboo fiber tufts into a blending hopper configured to blend
the bamboo fiber tufts, feeding the blended bamboo fiber tufts into a
beater configured to open the bamboo fiber tufts, and feeding the opened
bamboo fiber tufts into a fine opener configured to reduce the size of
the opened bamboo fiber tufts and refine the opened bamboo fiber tufts
into the bamboo fiberfill, wherein the bamboo fiberfill has a fiber
length of about 30 millimeters to about 60 millimeters and a linear
density of about 0.5 denier to about 5.0 denier.
1. A process for producing bamboo fiberfill from raw bamboo fiber,
comprising:obtaining a bale of the raw bamboo fiber;picking up and
separating the raw bamboo bale fiber into tufts of bamboo fiber with a
bale opener;feeding the bamboo fiber tufts into a blending hopper
configured to blend the bamboo fiber tufts;feeding the blended bamboo
fiber tufts into a beater configured to open the bamboo fiber tufts;
andfeeding the opened bamboo fiber tufts into a fine opener configured to
reduce the size of the opened bamboo fiber tufts and refine the opened
bamboo fiber tufts into the bamboo fiberfill, wherein the bamboo
fiberfill has a fiber length of about 30 millimeters to about 60
millimeters and a linear density of about 0.5 denier to about 5.0 denier.
2. The process of claim 1, further comprising forming the bamboo fiberfill into a nonwoven bamboo web, wherein forming the web comprises carding, garnetting, air-laying, dynamic random carding, or a combination comprising at least one of the foregoing methods.
3. The process of claim 2, further comprising layering the nonwoven bamboo web, wherein layering the web comprises longitudinal layering, cross-layering, perpendicular layering, or a combination comprising at least one of the foregoing methods.
4. The process of claim 3, further comprising bonding the nonwoven bamboo web, wherein bonding the web comprises needlepunching, stitch bonding, thermal bonding, chemical bonding, or a combination comprising at least one of the foregoing methods.
5. The process of claim 1, wherein feeding the bamboo fiber tufts into the blending hopper further comprises feeding the bamboo fiber tufts between an inclined needle apron and an evener roll.
6. The process of claim 1, wherein feeding the blended bamboo fiber tufts into the beater further comprises feeding the blended bamboo fiber through an opener roll comprising a lag pin.
7. A nonwoven filling made by the process of claim 1.
8. A household article employing the nonwoven filling of claim 7.
9. The household article of claim 8, wherein the article comprises a pillow, a quilt, a comforter, a furniture cushion, a blanket, a garment, an air filter, or a combination comprising at least one of the foregoing articles.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application Ser. No. 60/981,904, filed 23 Oct. 2007, which is incorporated herein by reference.
This disclosure relates to processes for making bamboo fiberfill, and to articles comprising the bamboo fiberfill.
A number of household textile articles are generally characterized as nonwoven fiberfill household textile articles. Broadly speaking, a fiberfill household textile article is comprised of a ticking or other type of casing filled with manufactured fibers, most commonly, polyester fibers, specially engineered for use as filling material. Common fiberfill household textile articles include beddings such as pillows, comforters, quilts, bedspreads, pads and other fiber products used or intended to be used on or about a bed or other place or other place for reclining or sleeping. For such articles, it is often desirable to have fibers with not only good resiliency and loft, but also anti-bacterial and deodorization properties as well.
Synthetic fibers are commonly used as nonwoven fiberfill for household textile articles. Examples of synthetic fibers include polyester, polypropylene, acrylics, nylon, rayon, and the like. Such synthetic fibers are chemically produced and can be thermally extruded and spun to form fibers. Synthetic fibers typically have high loft, low density, and good resiliency. Synthetic fibers typically do not have anti-bacterial or deodorization properties, and therefore, are often sprayed or coated after manufacturing with compounds to artificially give the fibers such properties. Moreover, synthetic fibers are produced from the hydrocarbons of fossil fuels, and they do not readily decompose after their disposal.
Natural fibers are also commonly used as nonwoven fiberfill. Examples of natural fibers include cotton, wool, hemp, silk, and the like. Natural fibers are formed from natural resources and typically readily decompose eliminating the waste and environmental concerns associated with synthetic fibers. Many of these natural fibers, however, also do not possess the anti-bacterial and deodorizing properties desirable in household bedding articles, and therefore, are also coated with artificial compounds.
Accordingly, it is desirable to produce a natural fiber that inherently possesses anti-bacterial and deodorizing properties, without the environmental concerns associated with synthetic fibers.
Disclosed herein is a process for producing bamboo fiberfill. In one embodiment, a process for producing bamboo fiberfill from raw bamboo fiber includes obtaining a bale of the raw bamboo fiber, picking up and separating the raw bamboo bale fiber into tufts of bamboo fiber with a bale opener, feeding the bamboo fiber tufts into a blending hopper configured to blend the bamboo fiber tufts, feeding the blended bamboo fiber tufts into a beater configured to open the bamboo fiber tufts, and feeding the opened bamboo fiber tufts into a fine opener configured to reduce the size of the opened bamboo fiber tufts and refine the opened bamboo fiber tufts into the bamboo fiberfill, wherein the bamboo fiberfill has a fiber length of about 30 millimeters to about 60 millimeters and a linear density of about 0.5 denier to about 5.0 denier.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an exemplary embodiment of a bale opener for use in the process of producing bamboo fiberfill;
FIG. 2 is a schematic view of an exemplary embodiment of a blending hopper for use in the process of producing bamboo fiberfill;
FIG. 3 is a schematic view of an exemplary embodiment of a Kirschner beater for use in the process of producing bamboo fiberfill;
FIG. 4 is a schematic view of an exemplary embodiment of a fine opener for use in the process of producing bamboo fiberfill;
FIG. 5 is a schematic view of an exemplary embodiment of a roller carding machine for use in the process of producing bamboo fiberfill;
FIG. 6 illustrates the carding section of a roller carding machine;
FIG. 7 is a schematic view of an exemplary embodiment of a aerodynamic web production machine for use in the process of producing bamboo fiberfill;
FIG. 8 is a schematic view of an exemplary embodiment of a vertical cross-lapper in operative communication with a roller carding machine for use in the process of producing bamboo fiberfill; and
FIG. 9 is a schematic view of an exemplary embodiment of a needlepunching machine for use in the process of producing bamboo fiberfill.
The inventors hereof have found that bamboo fiber can be processed and formed into a nonwoven web or air blown and used as fiberfill in articles such as bedding, quilting, pillows, comforters, blankets, home furnishing, and the like. The bamboo fiber is derived from the pulp of the bamboo plant. The bamboo plant is naturally anti-bacterial and possesses deodorizing abilities as well. The bamboo fiber retains these characteristics, and therefore, the fibers require no additional manufacturing processes or treatments to exhibit such qualities. As an added benefit, the bamboo plant can be grown without the need for environmentally harmful pesticides or fertilizers. The bamboo pulp can be processed into a fiber through a "green" process, having minimal environmental impact. All of these attributes make bamboo fiberfill a unique choice for household articles in an increasingly environmentally conscious consumer market.
Disclosed herein is an exemplary process for producing nonwoven fiberfill (i.e., filling) from bamboo fibers. In one embodiment, the process includes air blowing the fiber to explode the bamboo fibers and produce a highly resilient, high loft fiber for use in a pillow. In another embodiment, the bamboo fiber can be needlepunched to produce a dense, low loft nonwoven fiberfill for use in quilts and the like. In yet another embodiment, the bamboo fiber can be bonded to produce a high loft, resilient, and insulating nonwoven fiberfill for use in comforters and the like.
Raw bamboo fibers can be readily purchased in bulk form. The raw staple fibers can be shipped from the manufacturer in the form of bales. The process as disclosed herein begins with preparation of the raw staple bamboo fibers. In general, the bamboo fiber preparation includes mechanical and pneumatic processes from handling the fiber bale to the point where the bamboo fiber is introduced into a web-forming machine. This part of the process can sometimes be referred to as an opening line. The opening line is configured to reduce the size of the raw bamboo fiber tufts from the bale to a chute feed, which can supply a web forming machine. The opening line can comprise, among other things, a bale opener in operative communication with a blending hopper and feeder. For processes where the raw bamboo fiber is purchased in bale form, the bales can be first unstrapped and placed in line with the milling head of a bale opener. FIG. 1 illustrates one example of a bale opener 100. The bamboo fibers from one or more bales 102 can be picked up from the top of the bales by two opening rolls 104. An air vacuum can also be used in conjunction with the opening rolls to aid in the picking up of the fibers. The bale opener 100 can be in operative communication with a blending hopper (shown in FIG. 2) for receiving the separated raw fibers. The opening head assembly 106 containing the opening rolls 104, can traverse back and forth across the bale, and can start and stop on demand. Feedback from the blending hopper based on fiber level or weight can be used to start and stop the bale opener. The bale opener 100 can further comprise a density sensor 108 to determine changes in density of the raw bale fibers and to adjust the rate of fiber flow to the blending hopper as needed. Both the blending hopper feedback and the density sensors 108 are effective to ensure maximum efficiency and blending.
A blending hopper is generally illustrated in FIG. 2, and is labeled as reference numeral 200. The blending hopper can be configured to gently open the tufts of the bamboo fibers by the interaction of an inclined needle lattice apron 202 and an evener roller 204, which can also be equipped with needles. Raw bamboo fiber tufts from the bale opener 100 can be feed to the inclined apron 202 by a series of conveyors 206 that position the tufts inline with the apron. Blending of the bamboo tufts, which are clusters of small, flexible, soft bamboo fibers from different bales, occurs as the fibers are opened and mixed through the interaction of the inclined apron 202 and the evener roller 204. A stripper roller 208, in operative communication with the incline apron 202 and the evener roller 204, can be configured to pull off the opened, blended fiber tufts and deposit them into a weigh pan 210. The weigh pan 210 can be controlled by load cells (not shown) and can dump the blended bamboo fibers onto a feed conveyor upon reaching a desired fiber weight.
Turning now to FIG. 3, a blending conveyor 302 can feed the bamboo fiber tufts into an opening roll 304 of a beater 300. The beater 300 is a three-lag pin beater, as indicated by the number of lag pins 306 on the opening roll 304. Coarse opening of the bamboo fiber tufts occurs in the beater 300, which in this embodiment is known as a Kirschner beater. A series of feed rolls 308, in operative communication with the blending conveyor 302 can direct and advance the bamboo tufts into the three-lag pin opening roll 304. The three lag pins 306 of the opening roll are configured to coarsely open the bamboo tufts. In another embodiment, the opening roll can have more or less than three lag pins. The opening roll is configured to rotate at a speed effective to both open the bamboo fibers and advance the coarsely opened fibers out of the beater 300. A blower (not shown) can be used in operative communication with the beater 300 to help in removing the coarsely opened fibers from the beater.
The bamboo fiber, which has been opened by the beater 300 can then be transported (by the blower air) to the feed box 402 of a fine opener 400 (as shown in FIG. 4). The fine opener 400 can consist of two opening rolls 404, an evener roll 406 and a cylinder roll 408. In one embodiment, each of the rolls can be wound with metallic clothing. The bamboo fiber can first contact a condenser roll 410, which is configured to collect and regroup the fibers from the air blower. A reserve chute 412 and series of feed rollers 414 can be configured to control the supply of bamboo fiber to the opening rolls of the fine opener 400. The fine opener 400 is effective to reduce the tuft size of the bamboo fiber by using the principle of carding (which will be described in greater detail below) between the opening rolls 404 and the evener and cylinder rolls, 406 and 408. The reduced bamboo tufts are then transferred by the cylinder roll 408 to an air chute 416 that feeds a web-former.
To this point the fibers are opened and refined such that they present the qualities, such as resiliency, loft, density, and the like desired in household and bedding fiberfill articles. The process as disclosed herein can be effective to produce bamboo fibers having a fiber length of about 20 millimeters (mm) to about 70 mm, specifically about 30 mm to about 60 mm. The bamboo fibers can also have a linear density of about 0.3 denier to about 7.0 denier, specifically about 0.5 denier to about 5.0 denier. Moreover the process as disclosed herein can be employed to produce article comprising 100 percent by weight bamboo fiber. In other embodiments, the process can be used to refine the bamboo fiber for articles comprising less than 100 percent bamboo fiber. However, in order to impart the desirable qualities of the bamboo fiber onto a finished household article, it is desirable to have greater than or equal to about 50 percent by weight bamboo fiber. The bamboo fiber can be used in combination with one or more additional fibers, synthetic or natural. For example, the bamboo fiberfill can be combined with cotton fiber to form a cotton blend having anti-bacterial and deodorizing properties.
As previously mentioned, for pillow applications, a desired amount of the opened bamboo fibers formed by the process to this point can be separated prior to the web-former. The opened bamboo fibers at this point in the disclosed process are tangled in random fiber orientation. The tangled, exploded bamboo fibers can provide superior filling for high loft applications, such as pillows, furniture cushions, and the like. Blowers and fans can be used to further explode (i.e., fluff) the fibers and blow them into pillow envelopes, cushions, or the like depending upon the desired application. For these applications, the bamboo fibers do not need to be passed through Garnetts or formed into a web. The fibers at this point already have the resiliency required for such applications as pillows. As used herein, the term resiliency when referring to the bamboo fibers is generally intended to refer to the fibers ability to be compressed and to expand back to its original shape, thereby maintaining the comfort of the pillow.
For applications where a layered nonwoven web is more desirable than the tangled exploded bamboo fibers, such as for quilts, comforters, uniform pillows, bedding, and the like, the bamboo fibers can be formed into a web by a number of methods, all of which are intended to be included in the process for producing bamboo fiberfill as disclosed herein. The feed system for the web-forming machine will depend upon the method of web-forming selected and the type of web-former to be used. Chute feeding can be used for feeding bamboo fibers up to about 6 centimeters (cm) in length. When longer bamboo fibers are used, a hopper feed with a shaker-type chute can be used instead. A chute feed is shown in the first example of web-forming--carding.
FIG. 5 illustrates one embodiment of a card machine 500. Carding is a method of separating the small bamboo tufts into individual bamboo fibers, and it begins the process of parallelization, thereby delivering the fibers in the form of a web. The bamboo fibers are separated and oriented by the mechanical interaction of two opposing surfaces. The bamboo fibers can be held by one surface while the other surface combs the fibers causing individual fiber separation. The card machine 500 has a large rotating metallic cylinder 502 disposed in the center of the machine. The rotating cylinder 502 can be covered with card clothing 504, which is illustrated in more detail in FIG. 6. The card clothing 504 is comprised of needles, wires, fine metallic teeth, or the like embedded in a heavy cloth or in a metallic foundation. The rotation cylinder 502 can further be partly surrounded by a belt of a large number of flats positioned along the top of the cylinder, or by an assembly of alternating worker roll 506 and stripper rolls 508.
The bamboo fibers, after being fed by a chute or hopper, can be condensed into the form of a lap or batting. In this embodiment, the fibers exit the chute 510 as a condensed lap and enter a feed roll 512. The bamboo fiber lap can then initially be opened into small tufts by a licker-in 514, which feeds the fibers to the rotating cylinder 502. The needles of the two opposing surfaces of the rotating cylinder and the worker and stripper rolls are disposed at an incline in opposite directions and move at different speeds. FIG. 6 more clearly illustrates the relationship of the needled surfaces of each of the cylinder, worker, and stripper rolls. The rotating cylinder 502 moves faster than the worker and stripper rolls 506, 508. Due to the opposing needle orientations and the difference in speeds between the rolls, the bamboo fiber clumps are pulled and teased apart. The separation occurs between the worker roll 506 and the rotating cylinder 502, while the stripping roll 508 strips the larger bamboo tufts and deposits them back on the rotating cylinder 502. The fibers can be aligned in the machine direction (i.e. in the direction the fiber web is moving down the process line) and form a coherent web below the surface of the needles 504 of the rotating cylinder 502. The newly formed web can removed (i.e., doffed) from the surface of rotating cylinder by a doffer roll 516 and deposited onto a moving belt 518. In an exemplary embodiment, the orientation ratio of the bamboo fiber web at the doffer roll can be approximately 5:1 for the card machine 500. Moreover, the roller card machine can have a production performance of up to about 1000 kilograms per hour (kg/hr), and a web width of about 2 meters to about 3.5. In an alternative carding embodiment, a flat carding machine can be used to form a web of bamboo fibers. Flat carding machines, however, are not as efficient as roller card machines and typically produce about 1 meter wide webs at a rate of 5 kg/hr to about 50 kg/hr.
In another embodiment, a garnett can be used to separate the bamboo fibers and form a web. Typically, a garnett can include a group of rolls placed in an order that allows a given wire configuration, along with certain roll speed relationships, to level, transport, comb and interlock the bamboo fibers to a degree that a web is formed. The garnett can deliver a more randomly oriented web than a carding machine. Whether the method of carding or garneting is chosen to separate and orient the bamboo fibers, multiple machines can be used in series or parallel to produce a higher output of nonwoven bamboo fiber webs. Moreover, the webs from multiple garnetts or card machines can be layered, such as by cross-lapping, to build up the desired finished nonwoven weight, as will be described in more detail below.
In another exemplary embodiment of separating and orienting bamboo fibers to form a web, the web created by carding can be improved by capturing the bamboo fibers on a screen from an air-stream. Aerodynamic web formation, or Air-lay as it is sometimes called, can increase the uniformity of the web. A Rando-Webber component is an exemplary embodiment of an aerodynamic web production machine and is illustrated in FIG. 7 as reference numeral 700. Starting with a bamboo lap or bamboo card web, the bamboo fiber is fed by a feed table 702 into the machine, where the fibers are separated by a spiked roll 704 (or licker-in) and introduced into an air-stream. The air stream can be generated by a blower and ventilator 706. The air-stream blows the fibers onto a perforated cylinder roll 708, and the total randomization of the bamboo fibers precludes any preferred orientation when the fibers are collected on the perforated cylinder screen. The air-laid nonwoven bamboo web is randomized as opposed to the uniform or parallel structure of carding and garnetting webs. An air-laid bamboo fiberfill can be advantageous for use in applications such as air filtration media, where the randomized web is effective as a filtrate, and the bamboo fibers provide anti-bacterial properties to the filter. After the web-forming, the non-oriented bamboo fiber web can then be delivered to a draw-off conveyor 710 for transporting the web to a bonding area. The length of bamboo fibers that can be used in the air-laying process can be about 2 cm to about 6 cm. The shorter fiber lengths can allow higher production speeds, while the longer fibers require higher air volume, i.e., a lower fiber density to avoid tangling. Some disadvantages associated with air-laying can be production speed, web uniformity, and weight limitations. Due to the potential for uniformity problems, isotropic bamboo webs are generally greater than or equal to about 30 grams per square meter (g/m2). Air-laying, therefore, is slower than carding and, hence, more expensive. However, air-laying can provide bamboo fiber webs having a more isotropic, voluminous structure compared to carding and garnetting webs.
Yet another exemplary embodiment of separating and orientating the bamboo fibers to form a web is the centrifugal dynamic random card process. The centrifugal dynamic random card process forms a fiber web by throwing off the bamboo fibers from a cylinder onto a doffer roll with fiber inertia. The fibers are subject to centrifugal force in proportion to the square of the cylinder rotary speed. Through this method, orientation in the web can be three-dimensional and can be either random or isotropic. The random card method can produce about a 12 to about a 50 g/m2 web with fine bamboo fibers of about 1.5 denier, or a web of up to about 100 g/m2 with coarser bamboo fibers. The production of the random card can be generally about 30 to 50% higher than the conventional carding and garnetting processes as described above. The machine direction strength compared to the cross-direction strength (i.e., the direction perpendicular to the process line) can be better than for those bamboo webs produced by carding or garnetting, but typically are not as good as that of the air-laid webs. The number of machines required in the nonwoven bamboo fiberfill production process, however, can be reduced by the use of the random card method.
After the bamboo fiber has been formed into webs by any of the above described processes, the web formations can further be made into the desired web structure for a given application by layering of the bamboo webs. Layering can be accomplished in several ways to reach the desired weight and web structure.
In one embodiment, a longitudinal layering process can be employed. It can be advantageous to employ this process when one or more carding machines or garnets were used to form the bamboo web. The nonwoven webs from each of the cards or garnets are simply laid above one another on a conveyor belt, where the layered bamboo web can be optionally sent for bonding. When a longitudinal layering method is used, the layered webs tend to have anisotropic properties due to the unidirectional arrangements of fibers during layering. In other words, the layers tend to be organized uniformly over one another, with each layer in either the machine or cross directions.
In another embodiment, a cross-layering process can be used. The cross-layering process can be done by using two different devices, a vertical cross-lapper or a horizontal cross-lapper. A vertical cross-lapper 800 is shown in FIG. 8. The vertical cross-lapper includes a pendulum conveyor 802, which can be in operative communication with the conveyer roll 804 of a garnet or a card machine 806, as shown in FIG. 8. The pendulum conveyor 802 is configured to reciprocate back and forth and lay the nonwoven bamboo web into folds on another conveyor belt until the desired height or thickness is achieved.
In yet another embodiment, a perpendicular layering process can be used. This technique has an advantage over the longitudinal and cross layering processes because of the perpendicular and oriented fibers in the fabric. These perpendicularly layered nonwoven bamboo webs can have high resistance to compression and better recovery after repeated loading due to the orientation of the fibers in the layers.
Again, for pillow applications, a desired amount of the layered nonwoven bamboo web can be separated after layering, prior to reaching the bonding process. Alternatively, the nonwoven bamboo web can be bonded and used for pillow applications. For certain pillow applications, particularly those where a uniform pillow is desired without the lumps that can be associated with blown fiber, the layered nonwoven bamboo web can be cut to size and shape, rolled to a desired thickness, and slid into a pillow envelope.
For those applications were a uniform badding is desirable, such as filling for quilt and comforter articles, the layered nonwoven bamboo web can be bonded to form the bamboo fiberfill. The term bonding is generally intended to mean the process by which the nonwoven bamboo web is tacked together to form solid bamboo fiberfill structure that is not easily pulled apart. Examples of bonding include, without limitation, mechanical, chemical, and thermal bonding.
An exemplary embodiment of mechanical bonding is known as needlepunching. Needlepunching is a process of bonding the nonwoven bamboo web by mechanically interlocking the bamboo fibers throughout the web. Barbed needles, mounted on a board, punch the bamboo fibers into the web and then are withdrawn leaving the fibers entangled. The needles can be spaced in a non-aligned arrangement and are designed to release the bamboo fiber as the needle board is withdrawn.
An exemplary needlepunch process 900 is illustrated in FIG. 9. Needlepunched bamboo nonwovens can be created by mechanically orienting and interlocking the bamboo fibers of a garnet, air-laid, or carded web. This mechanical interlocking is achieved with a plurality of barbed felting needles 902 that repeatedly pass in and out of the nonwoven bamboo web 904. A needle board 906 provides the base unit into which the needles 902 are inserted and held. The needle board 906 can be disposed in a needle beam 908 configured to hold the needle board in place. A feed roll 910 and exit roll 912 can be driven rolls configured to move the web 904 through a needle loom 914. The needle loom 914 comprises a bed plate 916 and a stripper plate 918. The web 904 can pass through the two plates, with the bed plate being disposed beneath the web and the stripper plate above it. Corresponding holes are located in each plate and it is through these holes the needles 902 pass in and out. The needles carry bundles of the bamboo fiber through the bed plate holes. The stripper plate 918 is configured to strip the bamboo fibers from the needles 902 as the needles are retracted so that the web 904 can advance through the needle loom 914.
The shape of the needle is important to the process as it must push the fibers through the web in order to interlock, without damaging the web or removing the fibers as the needle retracts. The proper selection of gauge, barb, point type, blade shape (e.g. pinch blade, star blade, conical), and the like, are all examples of important needle design configurations and will depend on the type of bamboo fiber being used and the desired application for the nonwoven web. The gauge of the needle can be defined as the number of needles that can be fit in a square inch area. Thus the finer the needles, the higher the gauge of the needles. Coarse fibers can use lower gauge needles, while fine and/or delicate fibers will require higher gauge needles.
Continuing with the needlepunch process, as the needleloom beam 908 moves up and down, the blades of the needles penetrate the bamboo fiber batting. Barbs on the blade of the needle pick up the fibers on the downward movement and carry these fibers the depth of the needle penetration. The exit draw roll 912 pulls the bamboo batt through the needle loom 914 as the needles 902 reorient the bamboo fibers from a predominately horizontal to a substantially vertical position. The more the needles penetrate the web the denser and stronger the web generally becomes. However, care must be given as to the desired strength of the nonwoven web, as beyond a certain point, fiber damage can result from excessive needle penetration.
In another embodiment, a method of bonding the nonwoven bamboo fiberfill includes stitch bonding. Stitch bonding is another mechanical method of consolidating the bamboo fiber web with knitting elements to interlock the fibers. This process can include the use of a second material to interlock the bamboo fibers. A yarn-like fiber can be used, or a "scrim" substrate can be used and the bamboo fiber punched onto the scrim material. Examples of second materials will depend on the intended applications and the desired properties of those applications. As an example, Lycra® can be used if stretch in the fiberfill is a desired property. Stitch-bonded fiberfills tend to be used in place of woven goods, such as for bedding because they are faster to produce and, hence, the cost of production can be substantially less.
In yet another embodiment, a method of bonding the nonwoven bamboo fiberfill includes thermal bonding. Thermal bonding is a non-mechanical process, which uses heat to bond or stabilize the bamboo web structure. In order for thermal bonding to be useful for bamboo fiberfill, however, a thermoplastic fiber must also exist in the nonwoven web. As will be discussed in more detail below, the above disclosed processes can be useful for nonwoven fiberfill webs completely comprised of bamboo fiber or for nonwoven fiberfill webs wherein only a portion of the fiber is bamboo. For thermal bonding, the thermoplastic fibers are necessary in order to bind the bamboo fibers under heat. The fibers act as thermal binders, thus eliminating the need for latex or resin binders (other non-mechanical binding processes). Polypropylene can be a suitable fiber because it has a low melting point (approximately 165° C.), and therefore the heat will not damage the bamboo fibers. It is also soft to touch, so it does not impact the aesthetic properties of the bamboo. The nonwoven fiber web is passed between heated calender rollers, where the web is bonded. The calender rolls can be embossed or smooth. Embossed rolls can add softness and flexibility to the bamboo fiberfill, while smooth rolls bond the entire surface of the fiberfill, thereby increasing the strength, but reducing drape and softness.
In still another embodiment, the nonwoven bamboo fiberfill can be bonded by means of a chemical binder. The chemical binder can be applied to the web and then allowed to cure. The cured chemical is effective to provide the binding strength to the bamboo fiberfill. One example of a chemical binder is latex. Latex is commonly used because it is inexpensive, easy to apply, and very effective in binding the bamboo fibers. Several methods are used to apply the binder and can include saturation bonding, spray bonding, print bonding, foam bonding, and the like.
The mechanical type bonding, such as needlepunching, is effective in producing a dense, low-loft bamboo fiberfill having a felt-like quality. This material can be advantageously used filling, for example, in quilts used for the craft industry or for top of bed applications in the bedding manufacturing industry. The other types of bonding methods, such as thermal and chemical bonding, are effective in producing a high-loft, resilient, and insulating product. The product can be as much as about 2 inches thick and can be advantageously used in, for example, comforters and channeled comforter applications.
As previously noted, it has been discovered that when bamboo fiber is opened and then processed by way of web forming, layering, and bonding, the end result is a nonwoven fiberfill of bamboo which can be used as a quilt batting, filling for a blanket, filling for a comforter, the wrapping of a foam or polyester core pillow or cushion, garment or apparel creation, and the like. The bamboo fibers advantageously impart the unique attributes of the bamboo plant to the above listed articles. For example, an end product comprising nonwoven bamboo fiberfill will be naturally anti-bacterial, naturally deodorizing, and naturally breathable. Bamboo is also a highly absorbent material and can wick moisture away from the body, thereby offering a cooling effect in warmer climates and an insulating effect in cooler climates. When the bamboo fiber is processed through an opener and just a line of web forming machines (e.g. garnets), a highly lofted web of bamboo material is yielded, which can be used in applications such as bedding materials, including but not limited to quilts and comforters, however, this process offers a thicker, puffier, and more resilient result when finished in a quilt or comforter. When the bamboo fiber is further bonded by one of the methods listed in detail above, a tighter, denser web of bamboo material is formed, which can be used in the manufacture of quilts, blankets, and comforters. Even further, when the bamboo fiber is processed using the openers and the card or garnets in a random fiber orientation, where the fibers are tangled and exploded, the end product is a highly resilient fiber, which can be ideal for the use in the manufacture of pillows for bed pillows, bath pillows, travel pillows, craft pillows, lumbar pillows, decorator pillows, couch cushions, and the like. Moreover, if the bamboo fiber is blown, either with or without pre-opening the fiber, through the use of air and fans and tumbling through a pillow blowing machine, the end-result bamboo fiber can be blown into bed pillows, bath pillows, travel pillows, craft pillows, lumbar pillows, decorator pillows, couch cushions, and the like.
As can be seen, the process as disclosed herein provides methods for making several different options of bamboo fiberfill quality, and all of the bamboo fiberfill produced by the processes disclosed herein have properties that can not be achieved in other synthetic and natural fiberfills without the use of additional process steps and/or chemicals. Moreover, bamboo is a naturally occurring fiber that can be grown and harvested in a sustainably renewable manner and will readily decompose upon discarding, thereby further limiting environmental impact.
The terms "first," "second," and the like as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). Further as used herein "disposed" means that the recited elements are in direct contact with, and fully or partially cover each other. All ranges disclosed within this specification that are directed to the same component or property are inclusive of the stated endpoint, and are independently combinable. All references are incorporated herein by reference in their entirety.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention.