Abstract:
The instant application relates to a fiber bale and a method for producing the same. The instant fiber bale includes a highly compressed hexahedral fibrous material substantially free of disrupting curvatures on a top side or a bottom side. The highly compressed hexahedral fibrous material has a packing density of at least 300 kg/m 3 . The method for producing a fiber bale according to instant invention includes the following steps: (1) providing a press for producing a highly compressed hexahedral fibrous material comprising at least one convex bale platen; (2) filling the press with the fibrous material; (3) pressing the fibrous material via the press; (4) thereby forming the highly compressed hexahedral fibrous material; (5) packaging the highly compressed hexahedral fibrous material with a wrapping material; and (6) securing the wrapping material thereby producing the fiber bale.

Description:
FIELD OF INVENTION  
       [0001]     The instant application relates to a fiber bale and a method for producing the same.  
       BACKGROUND OF THE INVENTION  
       [0002]     Fibrous material, e.g. synthetic fibers and natural fibers, are sold and delivered to customers in compressed bales.  
         [0003]     Different methods are employed to produce high-density fiber bales. In general, a fibrous material is pressed into a bale, and covered with a protective wrapping. However, the conventional methods fail to produce a high-density fiber bale substantially free of disrupting curvatures on a top side or a bottom side. Disrupting curvature on either the top side or the bottom side is problematic because it interferes with the storage of high-density fiber bales on top of each other, and it promotes debating complications, for example in acetate tow bales.  
         [0004]     U.S. Pat. No. 3,991,670 discloses a pressing apparatus for compressing a mass of fibrous material, such as cellulose pulp, into a bale and wrapping the resulting bale with a wire or strap. There is used a bale press stand, a stationary first press plate movable toward, and away from said press plate, together with means for moving said second press plate. The second press plate has a pressure-applying face constituted by a planar border surface normal to the direction of movement of said second press plate and a centrally disposed portion projecting 10-50 mm from the plane of said border surface, for effecting a permanent depression, centrally in an end surface of a bale formed in said apparatus, facilitating the gripping and lifting of a wire or strap which is wrapped around a number of such bales.  
         [0005]     U.S. Pat. No. 4,577,752 discloses an improved high density tow bale wrapped with cardboard or the like covering and held in compressed condition by multiple strappings which extend around the bale, the tow bale having on its bottom a pattern of multiple pads for supporting the bale on a floor and unrelieved areas between the pads for receiving the strappings therealong.  
         [0006]     U.S. Pat. No. 5,852,969 discloses a bale press for compressing material such as cotton. The press includes a base frame structure and a pair of platens, which have generally rectangular bale compressing faces for compressing a cotton bale to facilitate the bale tying operation. A plurality of elongated, wedged-shaped, bale compression members are provided at least on one of the platens. These bale compression members protrude outwardly from the platen where they are mounted to provide a compression area, which is sufficiently small so that the cotton bale is compressed only in close proximity to the positions where a single bale tie is to be placed. A sufficient number of bale compression members are provided to facilitate the application of the ties required for the bale.  
         [0007]     German Utility Patent No. DE 296 15 598 U1 discloses the use of a conical shape compression shield and ejector to facilitate not only the compression of the materials downwardly, but also in the direction toward the side walls of the press.  
         [0008]     International Publication No. WO 03/089309 discloses a highly compressed cuboid-shaped filter tow bale having a top side and a bottom side free from noisome curvatures and constrictions. This bale is entirely wrapped with a mechanically self-supporting, elastic packing material, which is provided with one or several convectively airtight connections. The method for producing the highly compressed cuboid-shaped filter tow bale includes the following steps: a) filter tow is supplied in a compressed form; b) the compressed filter tow is enveloped in a wrapping; c) the wrapping is closed in an airtight manner; and d) the wrapped bale is relieved of the load (e.g., by application of vacuum).  
         [0009]     Despite the research efforts in developing high-density fiber bales suitable for storage and delivery, there is a still a need for a fiber bale, which is relatively easy to manufacture at a low cost. Furthermore, there is still a need for a method of producing high-density fiber bales suitable for storage and delivery, which requires the least amount of modifications of the current techniques and equipments, e.g. press, employed in producing high-density fiber bales.  
       SUMMARY OF THE INVENTION  
       [0010]     The instant application relates to a fiber bale and a method for producing the same. The instant fiber bale includes a highly compressed hexahedral fibrous material substantially free of disrupting curvatures on a top side or a bottom side. The highly compressed hexahedral fibrous material has a packing density of at least 300 kg/m 3 . The method for producing a fiber bale according to instant invention includes the following steps: (1) providing a press for producing a highly compressed hexahedral fibrous material comprising at least one convex bale platen; (2) filling the press with the fibrous material; (3) pressing the fibrous material via the press; (4) thereby forming the highly compressed hexahedral fibrous material; (5) packaging the highly compressed hexahedral fibrous material with a wrapping material; and (6) securing the wrapping material thereby producing the fiber bale.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     For the purpose of illustrating the invention, there is shown in the drawings a form that is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.  
         [0012]      FIG. 1  is a fiber bale according to instant invention;  
         [0013]      FIG. 2  schematically illustrates a cross sectional view of a convex bale platen; and  
         [0014]      FIG. 3  schematically illustrates a perspective view of a convex bale platen. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Referring to the drawings wherein like numerals indicate like elements, there is shown, in  FIG. 1 , a preferred embodiment of a fiber bale  10 . The fiber bale  10  includes a highly compressed hexahedral fibrous material  12  substantially free of disrupting curvatures on a top side or a bottom side. The highly compressed hexahedral fibrous material  12  has a packing density of at least 300 kg/m 3 , and it is completely encased with a wrapping material  14 . The wrapping material is preferably secured with a fastener (not shown). Additionally, the fiber bale  10  may include a vacuum, or in the alternative, it may be vacuum free.  
         [0016]     Substantially free of disrupting curvatures, as used herein, refers to a surface, which may be flat, slightly concaved, or slightly convexed.  
         [0017]     Vacuum, as used herein, refers to a reduced pressure generated by the removal of air, e.g. suctioning via an air pump or vacuum generated by retraction of bale platens.  
         [0018]     The highly compressed hexahedral fibrous material  12  may be composed of any fibrous material. Fibrous material, for example, includes natural fibers and synthetic fibers. Natural fibers include, but are not limited to, silk, wool, cotton, flax, jute, and ramie. The listed natural fibers are not regarded as limiting. Synthetic fibers include, but are not limited to, polymers synthesized from chemical compounds, e.g. acrylic, nylon, polyester, polyethylene, polylactic acid, polyurethane, and polyvinyl fibers, modified or transformed natural polymers, e.g. alginic and cellulose-based fibers such as acetates or rayons, and minerals, e.g. glasses. The listed synthetic fibers are not regarded as limiting. A preferred fibrous material is cellulose acetate tow.  
         [0019]     Wrapping material  14  may be any material that is durable enough to contain the highly compressed hexahedral fibrous material  12 . Wrapping material  14  may be a material selected from the group consisting of an air-permeable material, an air-impermeable material, and combinations thereof. For example, wrapping material  14  may be a material selected from the group consisting of a film, a cardboard, a woven material, a non-woven material, a foil material, and combinations thereof. A film, for example, may be a polymeric film such as a polyethylene film. A woven material is a fabric composed of two sets of yarns interlaced with each other to form the fabric. A non-woven material is the assembly of textile fibers held together by mechanical interlocking in a random web or mat, for example by fusing thermoplastic fiber to each other. Foil material may be any metallic material. The listed wrapping materials  14  are not regarded as limiting. Wrapping material  14  may include at least two portions, e.g. a top portion, and a body portion, or in the alternative, wrapping material  14  may include at least three portions, e.g. a top portion, a girth portion, and a bottom portion.  
         [0020]     Wrapping material  14  may further include the means for releasing vacuum. Means for releasing vacuum includes, but is not limited to, an opening (not shown). The opening may be a sealable opening, e.g. via a plug.  
         [0021]     Wrapping material  14  is preferably secured around the highly compressed hexahedral fibrous material  12  via a fastener (not shown). For example, wrapping material  14  may be secured around the highly compressed hexahedral fibrous material  12  via an air-permeable fastener (not shown). Air-permeable fastener may be any means for securing the wrapping material  14  around the hexahedral fibrous material  12 . For example, air-permeable fastener may be selected from the group consisting of Velcro, pin, hook, strap, and the like. The listed air-permeable fasteners are not regarded as limiting. In the alternative, wrapping material  14  may be secured around the highly compressed hexahedral fibrous material  12  via an air-impermeable fastener (not shown). Air-impermeable fastener may be any means for securing the wrapping material  14  around the hexahedral fibrous material  12 . For example, air-impermeable fastener may be selected from the group consisting of adhesive, melt bonding, and the like. The listed air-impermeable fasteners are not regarded as limiting.  
         [0022]     Referring to  FIGS. 2 and 3 , a conventional press (not shown) including at least one convex bale platen  18  is employed to facilitate the production of fiber bale  10 . A conventional press generally includes an upper platen and a lower platen, and either the upper platen or the lower platen may be a convex bale platen  18 . In the alternative, however, both upper platen and lower platen may be convex bale platens  18 . The convex bale platen  18  includes a convex surface  20 , discussed in greater detail below. Convex surface  20 , as used herein, refers to a surface curving outwardly, e.g. the surface of a sphere. Convex surface  20  is a smooth surface, e.g. continuous, faceted, or stepped. Convex surface  20  has a high point  22 , and a base  24 . The distance  26  between the high point  22  and the base  24  is about 1 cm to about 10 cm. For example, the distance  26  between the high point  22  and the base  24  may be about 5 cm. Convex surface  20  may be an integral component of convex bale platen  18 ; or in the alternative, it may be a separate component secured to convex bale platen  18  via the conventional methods. Convex surface  20  produces a temporary concave surface on the highly compressed hexahedral fibrous material  12 , which may gradually diminish within a short period of time due to the internal pressure of the highly compressed hexahedral fibrous material  12  thereby producing the fiber bale  10 . Convex surface  20  may include a groove or a channel (not shown) to facilitates the placement of a strap (not shown) upon fiber bale  10 . Preferably, convex surface  20  may include a plurality of grooves or channels (not shown) to facilitate the placement of plurality of straps (not shown) upon fiber bale  10 . Convex surface  20  may further include the means to generate strap slots (not shown) onto the fiber bale  10 . Means to generate strap slots include, but are not limited to, patterns, and impressions. Strap slot, as used herein, refers to a depression, e.g. a groove or a channel, on fiber bale  10 , which also facilitates the placement of a strap upon fiber bale  10 .  
         [0023]     In production, fibrous material is conveyed to a conventional press including at least one convex bale platen  18 . The upper platen and the lower platen are dressed with the wrapping material  14 . Conventional press including at least one convex bale platen  18  exerts a total pressure in the range of about 70 psi to about 700 psi on the fibrous material for a period of about 1 second to about several minutes thereby pressing the fibrous material into a highly compressed hexahedral fibrous material  12 . Subsequently, the conventional press including at least one convex bale  18  is retracted to allow the highly compressed fibrous material  12  to expand about 0 to about 25% by height. Next, the highly compressed hexahedral fibrous material  12  is packaged with the wrapping material  14 . Subsequently, the wrapping material  14  is secured with a fastener thereby producing fiber bale  10 . Vacuum may further be drawn on fiber bale  10 ; or in the alternative, fiber bale  10  may be vacuum free.  
       EXAMPLES  
       [0024]     Two fiber bale samples, as described hereinbelow in detail, were prepared, and the growth of the top surface of each fiber bale sample was measured to determine the increase in the height of their crown as a function of time. The results of the aforementioned test are shown below in Table I. The conditions for producing fiber bale samples 1 and 2 were exactly identical. Fiber bale sample 1 was produced using standard flat platens, and fiber bale sample 2 was produced using a top convex bale platen, according to instant invention.  
                                       TABLE I                                           After   After                   After 1   After 4   24   48               Immediately   Hour   Hours   Hours   Hours       Example   In   Out of   Out of   Out of   Out of   Out of       No.   Press   Press   Press   Press   Press   Press                   1   0 cm   4 cm   4.5 cm   5.2 cm   5.5 cm   6 cm       2   0 cm   0 cm   0.5 cm     2 cm   2.5 cm   3 cm                  
 
         [0025]     The present invention may be embodied in other forms without departing from the spirit and the essential attributes thereof, and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicated the scope of the invention.