Patent Document

BACKGROUND AND FIELD OF THE INVENTION 
     This invention relates to sorbent filter devices for removing contaminants from a confined environment such as computer disk drives and other electrical or optical devices. 
     Many electronic and/or optical devices are extremely sensitive to environmental contaminants particularly if the contaminants are gaseous in nature. Typically, the enclosures containing these sensitive devices are sealed, however, not hermetically sealed. Even if hermetic sealing were attempted, the devices would still be subjected to internally generated contaminants from out-gassing. As such, there is a need to remove harmful gaseous contaminants, whether the contaminants be internally generated to externally infiltrate into the enclosures, and whether the contaminants are organic, corrosive vapors, moisture, or the like. Also, as these devices are often small with limited available space it is desirable to provide sorbent filters which are small, yet can fit in available spaces and not shed particulates. It is known in the art to employ sorbent “breather” filters in enclosures of the above type. Known approaches to breather filters are discussed in U.S. Pat. No. 5,500,038 which states 
     “Sorbent breather filters used to keep particulates and vapors from entering enclosures are well known. These can be made by filling a cartridge of polycarbonate, acrylonitrile butadiene styrene (ABS), or similar material with sorbent and securing filter media on both ends of the cartridge. Examples of such filters are described in U.S. Pat. No. 4,863,499 issued to Osendorf, (an anti-diffusion chemical breather assembly for disk drives with filter media having a layer with impregnated activated charcoal granules); U.S. Pat. No. 5,030,260, issued to Beck et al. (a disk drive breather filter including an assembly with an extended diffusion path); U.S. Pat. No. 5,124,856, issued to Brown et al., (a unitary filter medium impregnated with activated carbon fibers to protect against organic and inorganic pollutants).” 
     This patent goes on to indicate that these known types of breather filters are unacceptable. The patent further describes the prior art approach of U.S. Pat. No. 4,830,643 where granular absorbent materials are filled in an expanded polytetrafluoroethylene tube (PTFE). This approach is also criticized in the &#39;038 patent for a number of reasons including the possibility that the loose fill can be spilled if the container tube is broken. As such, the &#39;038 patent proposes starting with a sorbent core material where the sorbent particles are immobilized by being held in a matrix, such as an impregnated nonwoven molded article with a binder or a sorbent particle filled polytetrafluoroethylene sheet. The immobilized carbon is then overwrapped, such as by a cigarette wrap, or filled into a preformed tube where end seals are provided by a potting technique. 
     A similar approach is proposed in PCT Appln. WO 98/41989, which proposes a shaped molded carbon article formed by compression molding a particulate absorbent with a mixed-in binder. The compression molded tablet or brick of absorbent material and binder can then be placed in a preformed container or pouch. 
     Compression molded or otherwise immobilized carbon particles, and other sorbents, formed into a preformed structure is well known in other fields as well. For example, in U.S. Pat. No. 3,474,600 (Tobias) molded tablets of absorbent carbon are formed under heat and pressure to form cigarette filters or cylindrical material for use in packed beds; U.S. Pat. No. 4,665,050 (Degen et al.) describes a specific process for molding sorbents with a binder to form monolithic shapes such as cylinders, a similar approach is also described in U.S. Pat. Nos. 4,664,683; 5,033,465 and 5,078,132 describe shaped structures formed by immobilized carbon, such as filter cakes for use in respirators; U.S. Pat. No. 5,332,426 describes forming various shaped structures from agglomerated sorbent granules where the agglomerate granules are formed with a plurality or sorbent particles which agglomerates are subsequently formed into structures by bonding together the agglomerates with the binder particles of the agglomerates; U.S. Pat. No. 3,091,550 describes forming a monolithic structure of activated carbon by use of emulsion binder or a binder suspended in an aqueous emulsion; U.S. Pat. No. 4,386,947 describes forming a extrudable dough-like mixture of activated carbon blended with a cellulosic material, water, varnish and an imide resin, where the dough is formed into a predetermined structure and heated to form a monolithic structure; U.S. Pat. No. 4,061,807 describes distributing a binder on an absorbent by mixing in a small amount of water, which is formed into a monolithic structure in a mold and is subsequently heated to drive off the water and activate the binder, UK Pat. 1,390,668 describes forming a variety of shapes by mixing a heated adsorbent with a binder forming the predetermined structure followed by a subsequent heating step to set the binder. Monolithic sorbent particle structures as such are very well known in the art. Often, the formed monolithic structures of sorbent particles and binders are subsequently overwrapped to contain any flaked off particles or the like, such as described in U.S. Pat. No. 5,500,038 and PCT WO 98/41989. This provides a further level of security, which is desirable where carbon or other particles are potentially extremely dangerous, such as in sensitive electronic components or where carbon or other particles can present a health concern. However, it is often quite difficult to overwrap a structure in a manufacturing process, particularly where the overwrap must necessarily cover all portions of the formed structure. Generally, where overwrapping is done, the monolithic structures are simple blocks or other symmetrical linear structures for ease of manufacture. However, with electronic enclosures such as disk drives and the like, the available space is generally quite limited and it is frequently desirable to provide for sorbent filters of complex shapes to take up as much available space as possible, or to take full advantage of the available space, or provide desirable flow patterns. As such, the invention is directed at a novel method of forming complex shaped sorbent filters of overwrapped immobilized sorbents in a simple and economical manner. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is directed at a method of forming a sorbent filter preferably having a three dimensional shape where the method includes the steps of 
     a) providing porous flexible tubular web structure having two open ends; 
     b) sealing a first end of the tubular web structure; 
     c) filling the sealed tubular web structure with flowable filter material or sorbent material and binder; 
     d) sealing the opposite open end of the tubular web material; and 
     e) heating the filled and sealed tubular web structure to activate the binder and form a shaped sorbent filter. 
     Preferably, while or after the binder is activated, the tubular web structure is deformed to create a bending portion resulting in a three dimensional shaped sorbent filter. 
     By “three dimensional” it is meant that the shaped sorbent filter, of an end sealed porous tubular web structure, has at least one bending portion along its length so that it is not a linear structure. Generally the bending portion has an angle of at least 10 degrees and the tubular web structure is filled with an immobilized filter material blend of sorbent and binder particles. 
    
    
     BRIEF SUMMARY OF THE DRAWINGS 
     FIG. 1 is a perspective view of a form, fill and sealed sorbent filter prior to deformation. 
     FIG. 2 is a perspective view of a form fill and sealed sorbent filter after deformation into a three dimensional shape. 
     FIG. 3 is a schematic illustration of the invention process. 
     FIG. 4 is graph of load verses extension curve of an invention sorbent filter. 
     FIG. 5 is a perspective view of a jig for use in deforming a sorbent filter as shown in FIG.  1 . 
     FIG. 6 is a perspective view of a jig being used to deform a sorbent filter as shown in FIG.  5 . 
     FIG. 7 is a top cutaway view of a deformed three dimensionally shaped sorbent filter of the invention in use in a computer disk drive. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 3, the sorbent filters of the invention are formed by a process  10  of filling a preformed flexible tubular web structure with a flowable filter material blend of sorbents and binder and sealing the ends of the tubular structure. This forms a precursor sorbent filter. The filled precursor sorbent filters are then formed into the invention sorbent filters by heating the precursor sorbent filter to activate the binder material immobilizing the filter material blend within the flexible tubular structure. This heating is preferably proceeded by or is simultaneous with a deformation or molding step to create a three dimensional sorbent filter. The flowable filter material blend is preferably premixed  32  to form sorbents  34  coated with a particulate binder  35 . The tubular web structure  38  material is porous and has two ends which in the formed sorbent filter are sealed, preferably by heat sealing. Other known methods of sealing off the ends of a tubular web structure, as known in the art, are also possible. In order to fill the flexible tubular web structure without contamination of the ends seals, generally one end of the tubular structure is presealed. The flowable filter material blend of preferably particulate sorbents and binder is then added into the opposing open end, which opposing end is then sealed. 
     A preferred method of forming sorbent filters employs a vertical form, fill and seal machine  36 , which machines are often used to package flowable materials. The flowable filter material blend or sorbent and binder particulates is fed into the vertical form fill and seal machine. For example, using such a machine a flat web of porous flexible web material is unwound from a roll and formed into a continuous tube in a tube forming section by sealing the longitudinal edges on the web together, such as by forming a lap seal  39  or a fin seal. The tube thus formed is pulled vertically downwards to a filling station. The tube is then collapsed across a transverse cross-section of the tube, the position of such cross-section being at a sealing device below the filling station. A transverse heat seal  31  is made, by the sealing device, at the collapsed portion of the tube, thus making an continuous seal across the tube. The sealing device generally comprises a pair of jaws. After making the transverse seal, but before the jaws of the sealing device are opened, a pre-set quantity of particulate material is allowed to enter the tube, at the filling station, and fill the tube upwardly from the transverse seal. The tube is then allowed to drop a predetermined distance under the influence of the weight of the material in the tube or by mechanical means such as the jaws or other means. The jaws of the sealing device are closed again, thus collapsing the tube at a second transverse section usually just above the air/material interface in the tube. The sealing device seals  33  and severs the tube transversely at said second transverse section. The material-filled portion of the tube is now in the form of an elongated pillow shaped pouch of a filled sorbent filter  38 , the pouch  38  contains the loose unconsolidated filter blend. Thus, the sealing device has heat sealed the top of the filled pouch, heat sealed the bottom of the next-to-be formed pouch and separated the filled pouch from the next-to-be formed pouch, all in one operation. 
     The filled flexible tubular structure  38  precursor sorbent filter as shown in FIGS. 1 and 3 is then heat set and preferably deformed or molded  44  into a complex three dimensional shaped structure such as a u-shape  42 , as shown in FIGS. 2 or  3 , or other shapes such as a s-shape, a v-shape, a w-shape or the like or a flat form  46 . The heat set is to activate the binder  35  and immobilize the particulate sorbents  34 . This deformation or molding step  40  can be carried out prior to, simultaneous with, or subsequent to the heating step  41  provided that the deformation and activation (i.e. prior to the binder has set by thermosetting, or solidifying, or the like) of the binder are coextensive over some period of time to allow the deformation to become permanent. Generally, the filled tubular structure  38  is filled to about 50 to 90 percent of its maximum capacity to permit the deformation step to be completed without rupture of the end seals ( 31  and  33 ) but still fill the tubular structure along its full length. With more complex shapes the percent to which the tubular structure is filled will be less, possibly even below the above range due to internal volume loss created by bending portions of the complex shape. 
     The sorbent material  34  can be any suitable sorbent which is capable of removing contaminants from air and is flowable. Particulate adsorbents are preferred, but absorbents are also contemplated, as are other shapes such as fibrous sorbents, provided that the sorbent material is still flowable. 
     The sorbent material used, as a particulate or other flowable form, is preferably an adsorbent activated carbon or silica gel. The adsorbent carbon particles are well known and described, for examples, in U.S. Pat. No. 4,061,807. The sorbent particle materials can be as small as 100 microns, but will typically have a size ranging from about 0.2 mm to about 2 mm, and preferably from about 0.4 to 0.7 mm. It is not necessary to have sorbent material of uniform size, rather the sorptive material size can range broadly. 
     The bonding material used is generally a particulate thermoplastic polymer binder  35  having a softening temperature below that of the sorptive material  34  and the porous flexible web material  20 . The average particulate size of the binder material should be less than that of the sorptive material. Generally the binder particle size will be about at least 20% less than the average sorptive particles size, and preferably about at least 90% less than the average sorbent particle size. However, it is generally preferred that the mean binder particle size less than about 250 microns, and preferably less than about 200 microns. Again, it is possible to use binder particles of a wide range of particle sizes and shapes provided that the average particle size is less than that of the sorptive material. Suitable thermoplastic polymer binders can be formed by polymers such as polyolefins, polyacrylates, polyarenes, polyamides, or thermoplastic elastomers such as polyurethanes, polydiene polymers and block copolymers, or the like. Generally, the selection of the thermoplastic binder is limited by softening point temperatures considerations and the ability to form the thermoplastic material into a fine binder particle. For example, higher softening point binders are preferred for higher service temperature applications. Also some binders are too tacky to form fine particles unless ground and stored under extreme temperature conditions, which is economically not feasible. 
     The binder particle  35  will typically constitute less than 40 weight percent of the flowable filter material  10 , preferably less than 25 weight percent, and most preferably less than about 15 weight percent of the filter material  10 . 
     The binder and sorbent material are preferably pre-blended to form the flowable filter material, with the binder adhered to the sorbent material as shown schematically as  32  in FIG.  3 . This is preferably done by preheating the sorbent material to a temperature about 5 to 10° C. above the softening temperature of the binder material. The heated sorbent material is then placed in a mixing device and the binder materials added without any consolidation pressure. It is possible to form agglomerates but preferably agglomerates are broken down by shearing elements provided in the mixing device. 
     The porous flexible web material  20  used to form the tubular structure is preferably a non-shedding nonwoven web such as a spunbonded web or like consolidated nonwoven web. Preferably the web material is formed of or contains a heat sealable thermoplastic. The flexible web material  20  can also be a porous film such as a polytetraflourethylene film or a non-shedding filter paper or laminate of any of the above. Generally, the porous web material contains only loose particulate material that may shake loose as well as permit the rapid penetration of gaseous contaminants. 
     The sorbent filter can have a three dimensional shape adapted to the available space provided in the intended electronic device  70  or the like as shown in FIG. 7 where the three dimensional sorbent filter  42  is fit into an available space in a hard disk drive. The sorbent filter  38  or  42  generally has an effective width (taken at the end seams) of less than 3 cm, preferably less than 2 cm, and a length of from less than 10 cm, preferably less than 6 cm. However, the length of the sorbent filter device is not critical. The effective width effects the ability to form the precursor sorbent filter  38  into suitable shapes. With smaller effective widths bending of the filled tubular web material  20  of the precursor sorbent filter  38  is easier, particularly when there are multiple bending portions that are closely spaced. The formed three dimensional filter device  42  is generally nonlinear with at least one bending portion  43  of angle  45  of at least 10 degrees, preferably at least 45 degrees. The bending portions  43 , when subject to deformation, have a shape retention (as defined below) of at least 35 percent, preferably at least 40 percent. Shape retention represents the ability of the filters to retain its shape when deformed. The filters as such exert a force that helps keep the filters in place by a friction fit when inserted into a space that deforms the filter from its as-formed shape. 
     EXAMPLES 
     Test Procedures 
     Shape Retention 
     Resiliency of a sorbent filter structure was evaluated by determining the available restoring energy of the filter according to procedures defined in the User&#39;s Guide, Instron Series XII Software, Issue C, September 1989, which utilizes a one kilogram cell on an Instron™ #4302 test apparatus (available from Instron Corp., Canton, Mass.). U-shaped filters as shown in FIG. 2, the preparation of which is described below, were placed between a 6.4 mm (0.25 inch) diameter probe and the base of the load cell (initial gap setting of 12 mm) such that the probe contacted the open end of the upper leg of the filter, the probe was advanced at a rate of 0.1 mm/sec over a distance of 4.5 mm followed by retraction to its original position at the same rate while the restoring energy for the body was monitored over both the loading and unloading cycles, and the available energy for the body was calculated by the instrumentation software supplied. The hysteresis loss C as a percentage of the loading energy or force (shown in FIG. 4) is calculated according to the equation: 
     
       
         (Loading Energy) (A)-(Unloading Energy (B))/(Loading Energy)×100 percent  
       
     
     This shape retention reported as a percentage in Table 2 is calculated by subtracting the hysteresis loss calculated by the above equation from 100 percent. 
     Moisture Adsorption 
     Duplicate sorbent filter samples were subjected to 90% relative humidity (RH) at 72° F. for 3 days while monitoring weight gain. Moisture adsorption is reported as the percent weight gain based on the weight of the sorbent filter. 
     Carbon Tetrachloride Adsorption 
     Duplicate sorbent filter samples were placed in a sealed container having a saturated carbon tetrachloride atmosphere, sustained by open beakers containing the solvent, for three days at ambient temperature while monitoring weight gain of the filters. Carbon tetrachloride adsorption is reported as the percent weight gain based on the weight of the sorbent filters. 
     Sorbents 
     Beaded Activated Carbon (BAC G-70R)—available from Kreha Corporation of America, Beaverton, Oreg. 
     K 2 CO 3  Treated Beaded Activated Carbon—BAC G-70R carbon (8.0 kg) was mixed with deionized water (8.0 kg) containing 0.8 wt. % K 2 CO 3 , the mixture was blended for approximately one-half hour and dried in a vacuum Rota-cone™ vacuum drier (available from Paul O. Abbe′, Inc., Little Falls, N.J.) for approximately 6½ hours. 
     Activated Carbon GAC type GG—(Carbon Coal, 25×45 screen size (0.71×0.35 mm), available from Kuraray Chemical Co., Ltd., Osaka, Japan). 
     Activated Carbon GAC type GG—(Carbon Coal, 16×35 screen size (1.19×0.5 mm), available from Kuraray Chemical Co., Ltd.). 
     Activated Carbon GAC type GG—(Carbon Coal, 12×20 screen size (1.68×0.84 mm), available from Kuraray Chemical Co., Ltd.). 
     Binders 
     Exxon Exact™ 4006—an ethylene based (co)polymer available from Exxon Chemical Company, Polymers Group, A Division of Exxon Corp., Houston, Tex.) which was cryoground, using standard procedures, to an average particle size of 140 μm. 
     3M Scotchcast™ 265 Epoxy (Stock #80-7002-6502-0)—an average particle size of 44 μm, available from 3M, St. Paul, Minn. 
     Morthane™ polyurethane resin—(P8455-200, available from Morton Thermoplastic Polyurethane Polymers Group, Seabrook, N.H.), which was cryoground, using standard procedures, to 120-160 μm, mean particle diameter size particles. 
     EXAMPLES 1-85 
     Sorbent particles and binder particles were mixed in the ratios indicated in Table 1 as follows: 
     Filter material blends utilizing the Exxon Exact™ 4006 polyethylene binder were prepared by heating the sorbent particles to 85-90° C. for approximately 15 minutes in a circulating air oven, adding the Exxon 4006 particles to the hot sorbent particles, and blending to produce a uniform mixture of sorbent particles with attached binder particles. After cooling to ambient temperatures the binder/sorbent particle mixture was passed through a number 20 sieve (mesh size 0.85 mm×0.85 mm) to break up and/or remove larger agglomerated clumps. The sieved filter material was used without further processing. 
     Filter material blends utilizing the Morthane™ polyurethane binder were prepared by heating the sorbent particles to approximately 170° C. for approximately 15 minutes in a circulating air oven, adding the Morthane™ polyurethane particles to the hot sorbent particles, and blending to produce a uniform mixture. After cooling to ambient temperatures the binding/sorbent particle filter material blend was processed through a number 20 sieve as described above. 
     Filter material blends utilizing the Scotchcast™ epoxy binder were prepared by blending the sorbent and epoxy particles for approximately 10 minutes at ambient temperatures to produce a uniform sorbent/binder particle filter material blend. 
     The carbon/binder filter material blends (0.5 gm per shaped body) were subsequently packaged in hand made tubular structures approximately 12 mm×36 mm (½ inch×1½ inch) formed from scrim laminated polytetrafluoroethylene (PTFE) film (available from BHA Technologies, Inc., Kansas City, Mo.). One open end of the tubular structures were heated sealed, the tubes were then filled and the opposite open end sealed to provide complete containment of the loose fill material in precursor sorbent filters. The filled tubular structures precursor sorbent filters were converted into u-shaped sorbent filters using a “T-shaped” channel jig assembly  50  as shown in FIG. 5 (2 mm wide×20 mm long top member and a nominally 8 mm wide×22 mm tall vertical member) which held the tubular structures during heating and allowed subsequent formation of the heated tubular structure into a U-shape. The precursor filters were inserted into the top member  52  of the T channel and the assembly placed in a circulating air oven  41  maintained at 105° C. for approximately two (2) minutes. The jig assembly  50  was subsequently removed from the oven and the tubular structure precursor sorbent filters  38  formed into a U-shaped sorbent filter  42  (12 mm×18 mm-½ inch×¾ inch) by deforming the tubular structure  38  within the vertical cavity member  53  of the jib assembly  50  using a 2 mm wide×20 mm tall blade  55  having a rounded edge  56  (approximately 2 mm diameter). The jig assembly  50  was then cooled to room temperature, the three dimensional shaped sorbent filter  42  was removed from the jig and characterized relative to its restoring energy, moisture absorption and carbon tetrachloride adsorption performance as described above, the results of which are reported in Tables 2-4 below. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Sorbent/Binder Compositions 
               
               
                 (Example Nos. in Bold) 
               
             
          
           
               
                   
                 Binder 
               
             
          
           
               
                   
                   
                   
                 Exxon 
                   
                   
               
               
                   
                   
                 Wt. % 
                 Exact 
                 Scotchcast 
                 Morthane 
               
               
                 Example 
                 Sorbent 
                 Binder 
                 4006 
                 265 
                 Polyurethane 
               
               
                   
               
             
          
           
               
                 
                   1-3 
                 
                 BAC G-70R 
                 1 
                   1   
                   2   
                   3   
               
               
                 
                   4-6 
                 
                 BAC G-70R 
                 3 
                   4   
                   5   
                   6   
               
               
                 
                   7-9 
                 
                 BAC G-70R 
                 5 
                   7   
                   8   
                   9   
               
               
                 
                   10-12 
                 
                 BAC G-70R 
                 10 
                 
                   10 
                 
                 
                   11 
                 
                 
                   12 
                 
               
               
                 
                   13-15 
                 
                 BAC G-70R 
                 15 
                 
                   13 
                 
                 
                   14 
                 
                 
                   15 
                 
               
               
                 
                   16-18 
                 
                 BAC G-70R 
                 20 
                 
                   16 
                 
                 
                   17 
                 
                 
                   18 
                 
               
               
                 
                   19-21 
                 
                 BAC G-70R 
                 30 
                 
                   19 
                 
                 
                   20 
                 
                 
                   21 
                 
               
               
                 
                   22-24 
                 
                 Treated 
                 1 
                 
                   22 
                 
                 
                   23 
                 
                 
                   24 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   25-27 
                 
                 Treated 
                 3 
                 
                   25 
                 
                 
                   26 
                 
                 
                   27 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   28-30 
                 
                 Treated 
                 5 
                 
                   28 
                 
                 
                   29 
                 
                 
                   30 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   31-33 
                 
                 Treated 
                 10 
                 
                   31 
                 
                 
                   32 
                 
                 
                   33 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   34-36 
                 
                 Treated 
                 15 
                 
                   34 
                 
                 
                   35 
                 
                 
                   36 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   37-39 
                 
                 Treated 
                 20 
                 
                   37 
                 
                 
                   38 
                 
                 
                   39 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   40-42 
                 
                 Treated 
                 30 
                 
                   40 
                 
                 
                   41 
                 
                 
                   42 
                 
               
               
                   
                 BAC G-70R 
               
               
                 
                   43-45 
                 
                 GG, 25x45 
                 1 
                 
                   43 
                 
                 
                   44 
                 
                 
                   45 
                 
               
               
                 
                   46-48 
                 
                 GG, 25x45 
                 3 
                 
                   46 
                 
                 
                   47 
                 
                 
                   48 
                 
               
               
                 
                   49-51 
                 
                 GG, 25x45 
                 5 
                 
                   49 
                 
                 
                   50 
                 
                 
                   51 
                 
               
               
                 
                   52-54 
                 
                 GG, 25x45 
                 10 
                 
                   52 
                 
                 
                   53 
                 
                 
                   54 
                 
               
               
                 
                   55-57 
                 
                 GG, 25x45 
                 15 
                 
                   55 
                 
                 
                   56 
                 
                 
                   57 
                 
               
               
                 
                   58-60 
                 
                 GG, 25x45 
                 20 
                 
                   58 
                 
                 
                   59 
                 
                 
                   60 
                 
               
               
                 
                   61-63 
                 
                 GG, 25x45 
                 30 
                 
                   61 
                 
                 
                   62 
                 
                 
                   63 
                 
               
               
                 
                   64-66 
                 
                 GG, 16x35 
                 1 
                 
                   64 
                 
                 
                   65 
                 
                 
                   66 
                 
               
               
                 
                   67-69 
                 
                 GG, 16x35 
                 3 
                 
                   67 
                 
                 
                   68 
                 
                 
                   69 
                 
               
               
                 
                   70-72 
                 
                 GG, 16x35 
                 5 
                 
                   70 
                 
                 
                   71 
                 
                 
                   72 
                 
               
               
                 
                   73-75 
                 
                 GG, 16x35 
                 10 
                 
                   73 
                 
                 
                   74 
                 
                 
                   75 
                 
               
               
                 
                   76-78 
                 
                 GG, 16x35 
                 15 
                 
                   76 
                 
                 
                   77 
                 
                 
                   78 
                 
               
               
                 
                   79-81 
                 
                 GG, 16x35 
                 20 
                 
                   79 
                 
                 
                   80 
                 
                 
                   81 
                 
               
               
                 
                   82-84 
                 
                 GG, 16x35 
                 30 
                 
                   82 
                 
                 
                   83 
                 
                 
                   84 
                 
               
               
                 
                   85 
                 
                 GG, 12x20 
                 10 
                 — 
                 — 
                 
                   85 
                 
               
               
                 
                   86 
                 
                 GG, 12x20 
                 17 
                 — 
                 — 
                 
                   86 
                 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Shape Retention 
               
               
                 [% Shape Retention (Example No.)] 
               
             
          
           
               
                   
                 Binder 
               
             
          
           
               
                   
                   
                 Wt. % 
                 Exxon Exact 
                 Scotchcast 
               
               
                 Example 
                 Sorbent 
                 Binder 
                 4006 
                 265 
               
               
                   
               
             
          
           
               
                 
                   22 
                 
                 Treated 
                 1 
                 29.9% ( 22 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   25-26 
                 
                 Treated 
                 3 
                 40.6% ( 25 ) 
                 34.8% ( 26 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   28 
                 
                 Treated 
                 5 
                 41.2% ( 28 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   31 
                 
                 Treated 
                 10 
                 49.3% ( 31 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   34-35 
                 
                 Treated 
                 15 
                 61.5% ( 34 ) 
                 29.0% ( 35 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   37 
                 
                 Treated 
                 20 
                 51.8% ( 37 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   40-41 
                 
                 Treated 
                 30 
                 65.4% ( 40 ) 
                 26.3% ( 42 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   43 
                 
                 GG, 25x45 
                 1 
                 20.9% ( 43 ) 
                 — 
               
               
                 
                   46-47 
                 
                 GG, 25x45 
                 3 
                 34.5% ( 46 ) 
                 24.1% ( 47 ) 
               
               
                 
                   49-50 
                 
                 GG, 25x45 
                 5 
                 29.1% ( 49 ) 
                 26.8% ( 50 ) 
               
               
                 
                   52 
                 
                 GG, 25x45 
                 10 
                 36.5% ( 52 ) 
                 — 
               
               
                 
                   55-56 
                 
                 GG, 25x45 
                 15 
                 47.9% ( 55 ) 
                 25.6% ( 56 ) 
               
               
                 
                   58 
                 
                 GG, 25x45 
                 20 
                 44.7% ( 58 ) 
                 — 
               
               
                 
                   61 
                 
                 GG, 25x45 
                 30 
                 51.7% ( 61 ) 
                 — 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Moisture Adsorption 
               
               
                 Wt. % H 2 O Adsorbed based on Shaped Sorbent Filter Wt. 
               
               
                 [% Water Adsorbed (Example No.)] 
               
             
          
           
               
                   
                 Binder 
               
             
          
           
               
                   
                   
                 Wt. % 
                 Exxon Exact 
                 Scotchcast 
               
               
                 Example 
                 Sorbent 
                 Binder 
                 4006 
                 265 
               
               
                   
               
             
          
           
               
                 
                   22 
                 
                 Treated 
                 1 
                 43.9% ( 22 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   25-26 
                 
                 Treated 
                 3 
                 42.6% ( 25 ) 
                 40.6% ( 26 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   28-29 
                 
                 Treated 
                 5 
                 42.3% ( 28 ) 
                 40.5% ( 29 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   31 
                 
                 Treated 
                 10 
                 40.5% ( 31 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   34 
                 
                 Treated 
                 15 
                 36.9% ( 34 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   37 
                 
                 Treated 
                 20 
                 38.7% ( 37 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   40-41 
                 
                 Treated 
                 30 
                 32.7% ( 40 ) 
                 35.3% ( 41 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   43 
                 
                 GG, 25x45 
                 1 
                 48.5% ( 43 ) 
                 — 
               
               
                 
                   46-47 
                 
                 GG, 25x45 
                 3 
                 48.6% ( 46 ) 
                 47.7% ( 47 ) 
               
               
                 
                   49 
                 
                 GG, 25x45 
                 5 
                 47.6% ( 49 ) 
                 — 
               
               
                 
                   52 
                 
                 GG, 25x45 
                 10 
                 45.0% ( 52 ) 
                 — 
               
               
                 
                   55-56 
                 
                 GG, 25x45 
                 15 
                 43.6% ( 55 ) 
                 44.3% ( 56 ) 
               
               
                 
                   58 
                 
                 GG, 25x45 
                 20 
                 39.5% ( 58 ) 
                 — 
               
               
                 
                   61-62 
                 
                 GG, 25x45 
                 30 
                 33.3% ( 61 ) 
                 42.1% ( 62 ) 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Carbon Tetrachloride Adsorption Data 
               
               
                 Wt. % CCl 4  Adsorbed based on the Shaped Sorbent Filter Wt. 
               
               
                 [% CCl 4  Adsorbed (Example No.)] 
               
             
          
           
               
                   
                 Binder 
               
             
          
           
               
                   
                   
                 Wt. % 
                 Exxon Exact 
                 Scotchcast 
               
               
                 Example 
                 Sorbent 
                 Binder 
                 4006 
                 265 
               
               
                   
               
             
          
           
               
                 
                   22 
                 
                 Treated 
                 1 
                 74.1% ( 22 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   25-26 
                 
                 Treated 
                 3 
                 73.0% ( 25 ) 
                 66.2% ( 26 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   28-29 
                 
                 Treated 
                 5 
                 72.9% ( 28 ) 
                 65.0% ( 29 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   31 
                 
                 Treated 
                 10 
                 73.2% ( 31 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   34-35 
                 
                 Treated 
                 15 
                 66.2% ( 34 ) 
                 60.1% ( 35 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   37 
                 
                 Treated 
                 20 
                 65.2% ( 37 ) 
                 — 
               
               
                   
                 BAC G-70R 
               
               
                 
                   40-41 
                 
                 Treated 
                 30 
                 60.1% ( 40 ) 
                 57.4% ( 41 ) 
               
               
                   
                 BAC G-70R 
               
               
                 
                   43 
                 
                 GG, 25x45 
                 1 
                 84.8% ( 43 ) 
                 — 
               
               
                 
                   46-47 
                 
                 GG, 25x45 
                 3 
                 85.7% ( 46 ) 
                 71.5% ( 47 ) 
               
               
                 
                   49-50 
                 
                 GG, 25x45 
                 5 
                 84.6% ( 49 ) 
                 75.1% ( 50 ) 
               
               
                 
                   52 
                 
                 GG, 25x45 
                 10 
                 77.9% ( 52 ) 
                 — 
               
               
                 
                   55-56 
                 
                 GG, 25x45 
                 15 
                 74.8% ( 55 ) 
                 66.2% ( 56 ) 
               
               
                 
                   58 
                 
                 GG, 25x45 
                 20 
                 77.7% ( 58 ) 
                 — 
               
               
                 
                   61-62 
                 
                 GG, 25x45 
                 30 
                 63.7% ( 61 ) 
                 53.4% ( 62 ) 
               
               
                   
               
             
          
         
       
     
     The data in Tables 2-4 suggest that a broad range of binder and sorbent materials can be used to prepare consolidated sorbent bodies. Restoring energy for the shaped sorbent filter can be adjusted over a rather broad range by increasing or decreasing the amount of binder material and/or binder type to optimize the properties of the shaped sorbent filter for a specific application. Generally speaking, constructions based on the polyethylene binder showed greater respective energy or shape retention at higher binder content but at the exposure of lower sorptive capacity. Constructions based on polyethylene binders were also more resilient than constructions based on the epoxy binder. 
     EXAMPLE 87 
     A number of loose fill tubular structures of Example 10 were placed on a tray and heated at 105° C. for approximately two (2) minutes. On removal from the oven the hot pouches were formed into a variety of shapes, including “j”, “s”, “o”, “v”, “l”, “w”, “z”, and “c” shapes, as well as a twisted rod shape, by manually forming the tubular structure into the desired shape and maintaining it in that shape until it had cooled to ambient temperature. 
     This example demonstrates the versatility of the loose fill approach to form sorbent shaped filter constructions in that a wide range of over-wrapped constructions can be easily and conveniently fabricated from the loose fill tubular structures.

Technology Category: 4