Patent Publication Number: US-2005126690-A1

Title: Process for manufacturing resin-based composite material

Description:
TECHNICAL FIELD  
      The subject application relates to a method and apparatus for the manufacture of fiber-reinforced panels.  
     BACKGROUND OF THE INVENTION  
      It is commonplace in the recreational vehicle business to use glass fiber-reinforced wall panels for the exterior surface of the recreational vehicle. These wall panels vary in widths up to, and including, dimensions from 2.4 to 3 meters (8 to 10 feet), and can have a length as long as 12 meters (40 ft.) or more. While the composite material from which the panels are made provides an adequate material for the recreational vehicle side walls, the presently utilized equipment for manufacturing the composite material invariably may emit VOCs, both within the facility, as well as that which may be exhausted to atmosphere.  
      The process of making the composite material first begins with use of an elongate mold. The mold is somewhat larger than the panels to be made, but large enough to accommodate the 3×12 meter (10×40 ft.) panels. The upper surface is a finished surface to provide a substantially flat and smooth surface, as it is this surface which forms the exterior surface of the panels to be made.  
      The mold is first sprayed with a coating known as a gel coating, which cures to form a high gloss exterior surface for the panel. Once cured, a resin and fiberglass are placed on the backside of the gel coating, and then a plurality of panels of hard board (such as luan panels) are positioned side by side on top of the fiberglass. A vacuum bag is then placed over the top of the panels and a slight vacuum is introduced which draws resin into the luan panels to form a finished product. The completed product is then pulled off of the mold and cut and trimmed to the proper size.  
      One method of applying the gel coating is to maintain the elongate mold in a stationary fashion, and move the gel coating sprayer longitudinally along rails and spray the entire length of the elongate mold. While this provides for an excellent layer of gel coating on the mold, due to the movement of the sprayer, capturing the fumes of the gel coating can be difficult. Furthermore, as maintenance of the molds is required, the molds are moved into and out of their various positions by way of an overhead crane, which due to the size of the elongate mold, can be a dangerous operation.  
      The object of the invention is to overcome the shortcomings of the prior art.  
     SUMMARY OF THE INVENTION  
      The objects of the invention have been accomplished by providing an apparatus for manufacturing glass fiber-reinforced sheet, comprising an upper movable surface being arranged in a longitudinal manner; a feed mechanism to continuously feed sheet onto the upper movable surface, a spray mechanism to spray a first outer coat of material onto the moving sheet, at least one dispensing mechanism to dispense resin over a layer of first outer coat, at least one applicator mechanism to apply fiber strands over the resin, a loading area whereby sheet panels may be positioned over the fiber strands, and a mechanism to draw resin applied to the sheet panels into the sheet panels to form a rigid composite material.  
      In a preferred embodiment of the invention, the upper movable surface is defined by a continuous loop of individual links. The links are elongate in width and connect to adjacent links along their front and rear edges. The apparatus further comprises a rail member positioned below the links defining a reference surface, and the links have a lower foot portion which registers with the links to define a horizontal plane on the upper movable surface. Each foot portion has a wear bar comprised of a low friction surface which slides relative to the reference surface.  
      Also preferably, the drawing mechanism is a pressure application mechanism, and is comprised of a second continuous loop of individual links, positioned in a spaced apart position from the first continuous loop.  
      The sheet is comprised of a roll of sheet material of high tensile strength, and a take up roller is also included to roll up the sheet material at the opposite end: The apparatus further comprises a roller table adjacent the take up roller, whereby finished fiberglass-reinforced sheet may be continuously fed onto the roller table.  
      In another embodiment of the invention, an apparatus for manufacturing fiberglass-reinforced sheet, comprises a mold surface being arranged in a longitudinal manner, onto which the fiberglass-reinforced sheet may be formed, a spray mechanism to spray a first outer coat of material onto the mold surface, at least one dispensing mechanism to dispense resin over a layer of first outer coat, at least one applicator mechanism to apply fiber strands over the resin, and an automatic roller mechanism which performs transverse rolling patterns across the mold surface.  
      In a preferred embodiment of the invention, the automatic roller mechanism is comprised of at least one roller which is driven in a continuous loop in a direction transverse to the longitudinal direction. The mold surface is preferably movable in the longitudinal direction. The roller mechanism is profiled to move the at least one roller in a direction, such that the roller has a transverse velocity component and a longitudinal velocity component, whereby the longitudinal velocity component is equal to a longitudinal velocity of the moving mold surface. The roller mechanism is comprised of a driven chain loop guided around a chain guide, and the roller is attached to and driven by the chain loop. The chain guide is movable to various angles to vary the angle of the chain guide relative to the longitudinal direction. Preferably, a plane of the chain guide is tipped relative to a plane of the mold surface. Also preferably, a plurality of rollers are attached to and driven by the chain loop.  
      a preferred embodiment of the invention, the movable mold surface is defined by a roll of film together with a feed mechanism to feed the film at a first end, and a take up roller at a second end. A movable support surface is positioned beneath the movable mold surface. The movable mold surface and the movable support surface are moved together at substantially the same speeds. The movable support surface is defined by a continuous loop of individual links. Preferably, a rail member is positioned below the links defining a reference surface, and the links have a lower foot portion which registers with the links to define a horizontal plane.  
      In yet another embodiment of the invention, a method for manufacturing fiberglass-reinforced sheet, comprises the steps of feeding a sheet of material over a support surface, applying a first outer coat of material to the sheet, applying at least a first coat of resin over the first out coat, applying fiber strands over the resin, positioning wood reinforcement sheets over the fiberglass, and forcing the resin into the wood reinforcement sheets to form a composite material.  
      A preferred method further comprises the step of moving the support surface at the same speed as the sheet of material. The sheet of material is taken up by a take up roller, and a continuous sheet of fiberglass-reinforced sheet is moved tangentially away from the sheet of material. A preferred method also includes the step of rolling the fiber strands into the resin. The rolling is generally transverse to the direction of feed. The rolling is accomplished by moving at least one roller in a direction, such that the roller has a transverse velocity component and a longitudinal velocity component, whereby the longitudinal velocity component is equal to the longitudinal velocity of the sheet feed. Preferably, the rolling is accomplished by the use of a plurality of rollers. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIGS. 1A-1E  show a side plan view of the continuous mold apparatus of the subject invention;  
       FIG. 2  shows an enlarged view of the mold track and feed section;  
       FIG. 3  shows an enlarged view of the mold track links;  
       FIG. 4  shows an enlarged view of the pressure track;  
       FIG. 5  shows an end view of the fiberglass roller mechanism;  
       FIG. 6A  shows a top plan view of the chain guide mechanism of  FIG. 5 ;  
       FIG. 6B  shows an end view of the chain guide mechanism of  FIG. 6A ; and  
       FIGS. 7A and 7B  show diagrammatical views of two various positions of the fiberglass roller mechanism of  FIG. 5  with different linear speeds of the continuous mold apparatus. 
    
    
     DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION  
      With reference now to  FIG. 1A , a continuous molding apparatus is shown generally at  2 , which includes a MYLAR sheet or film feed station  4 , (MYLAR is a registered trademark of E.I. Du Pont de Nemours) which feeds MYLAR sheet onto a support track mechanism  6 , which is fixed and guided by a sub-frame member  8 . A spray apparatus  10  spans the width of the support track mechanism  6  and includes a spray head  12  as will be described herein. Downstream of the spray apparatus  10  is an oven  14  which is enclosed and extends for some length as depicted in  FIGS. 1B and 1C . Downstream of the oven  14  is a first resin-dispensing station  16 , which applies a first spray of resin through spray head  18  and a first coating of chopped fiberglass through fiberglass applicator station  20 . Downstream of applicator  16  is an automatic roller mechanism  22 , which will be described in greater detail herein. As shown in  FIG. 1D , a second resin-dispensing station  24  is positioned downstream of the first resin-dispensing station  16  and is substantially identical to first resin-dispensing station  16 , including a second resin spray head  26  and a second fiberglass applicator station at  28  (alternatively, the second resin applicator may not be required, depending on the input materials, the physical requirements of the panel, and the capacity of the first resin applicator). Downstream of the second applicator station  24  is a second automatic roller mechanism  30 , which is identical to roller mechanism  22 . As shown in  FIG. 1D , a board loading station is provided at  32 , whereby sheets of wood product can be placed above the fiberglass as described further herein. With reference now to  FIG. 1E , a pressure roller track is shown at  34 , while a MYLAR sheet take-up apparatus is shown at  36 . One skilled in the art appreciates the film may comprise other materials than MYLAR, so long as the strength, durability, chemical compatibility, release, and other requirements are met. One skilled in the art further appreciates the chopped glass fibers may alternatively comprise a reinforcement mat, a chopped polymeric, natural or other fiber, or a sheet of other material having the desired characteristics.  
      With reference now to  FIG. 2 , the sub-frame  8  is shown as including a plurality of vertical legs  40 , together with a plurality of horizontal beams, such as  42  and  44 , which form the rigidity for the molding apparatus. As should be appreciated by one skilled in the art, many variations and forms could be provided without varying from the scope of the invention. It is anticipated that such frame members include structurally rigid items, such as steel channels, angle iron or the like, to form a rigid sturdy frame for the molding process. As shown in  FIG. 2 , the sub-frame further includes a pair of roll mounting arms  46  (only one of which can be viewed in  FIG. 2 ) together with a support rod such as  48 . As shown in  FIG. 2 , arms  46  would include mounting apertures for receiving a rod, such as  50 , for mounting a roll as further described herein. Finally, feed station mechanism  4  includes a tension roller mechanism  52  comprising two idler tension rollers  54  and  56 .  
      With reference still to  FIG. 2 , support track mechanism  6  includes a roller  60 , which is pinned to horizontal bar  42  at  62 . A chain link mechanism is provided at  70 , which extends around roller  60  and around roller  64  ( FIG. 1E ) positioned at the opposite end of the mechanism  2 . As shown best in  FIG. 3 , chain  70  is formed from a plurality of links  72 , which are identical and which fit together at their ends. In a preferred embodiment of the invention, links  72  are extruded from a plastic material and include a body section  74  having an upper finished surface at  76 , with a male connection end  78  at one end and a female connection end  80  at the opposite end. The links  72  further include a T-shaped bar  82  extending from a lower surface  84  of the link and which receives a low friction slide  86  having a complementary T-shaped slot  88 .  
      Finally, and with respect still to  FIG. 2 , the roller guide mechanism  6  further includes a guide rail mechanism  90  comprised of a support portion  92  and an upper slide portion  94 , having a slide surface at  96  and a lead-in section at  98 . It should be appreciated that the width of each of the links  72  is at least as wide as the width of the panel to be manufactured, that is, at least 8′ wide. Thus, the guide mechanism  90  could either be a unitary member, where the upper slide section  94  is continuous for the entire width, with a plurality of integrally formed structural ribs  99  extending laterally therealong. Alternatively, the guide members  90  could be T-shaped members, whereby section  94  forms the horizontal section of the T, and section  99  forms the vertical section of the T. In this way, the members  90  would be positioned laterally across the width of the device, for example, at spacings of 12 inches. It should be understood, however, that the rails  90  extend the entire length of the apparatus  2 , and thus a plurality of sections of guide members  90  will be required, regardless of the configuration as mentioned above. However, the upper surface  96  of the guide members  90 , when installed, should be polished to form a relatively flat and consistent reference surface, as will be described herein.  
      With reference again to  FIGS. 1A and 1B , while the spray apparatus  10  and oven  14  are relatively conventional items, they will be described in somewhat greater detail for completeness. As mentioned above, the spraying apparatus  10  spans the width of the track links  72  and includes a spray head  12 . The spray head also spans transversely across the links  72  and is profiled to discharge a gel coating in a spray pattern and with relatively uniform thickness. Such spray apparatus may be obtained commercially, for example from Magnum Venus of Kent, Wash. As the gel coating requires curing, a curing oven  14  is included downstream of the spray apparatus  10 . The oven encloses the individual track members  72  to maintain the inner temperature at a range of approximately 100°-120° F. With reference to  FIG. 1C and 1D , applicators  16  and  24  are also somewhat conventional, and include resin spray heads  18 ,  26 , and fiberglass applicators  20  and  28 . It should be appreciated that the applicators  20  and  28  are designed for chopping fiberglass fibers and dispensing them in various sizes to form a composite material as will be described herein. Such chopper and spray apparatus may be obtained commercially, for example from Magnum Venus of Kent, Wash.  
      As shown in  FIGS. 1E and 4 , a pressure roller mechanism  34  is shown, which is substantially similar to roller mechanism  6 , and includes track links  72 , which are identical to that described above, and are linked around rollers  100 ,  102  as shown in  FIGS. 1E  and  4 . Roller  100  is pinned at  104  to cross bar  106  fixing the rollers in a spaced relation as shown in  FIG. 1E . The pressure roller mechanism  34  may also optionally include a guide mechanism  90  identical to that described with reference to  FIG. 2 , yet inverted as shown in  FIG. 4 . As also shown in  FIG. 4 , it should be appreciated that the tracks are positioned such that a gap  110  is formed between opposing surfaces  96  of the links  72 .  
      With respect again to  FIG. 1E , take-up roller mechanism  36  includes arms  146  and tension roller mechanism  152 , which are directly analogous to arms  46  and tension roller mechanism  52  as should be appreciated by those skilled in the art.  
      With respect now to  FIGS. 1C and 1D , the molding apparatus includes automatic roller mechanisms  170 , which are adjustable given the speed of the apparatus, and which are adjustable to accommodate different speeds. With reference now to  FIGS. 5, 6A  and  6 B, the roller mechanism  170  will be described in greater detail. As shown first in  FIG. 5 , roller mechanism  170  includes a chain drive mechanism  172 , a chain link  174 , and a plurality of mounting arms  176 , which mount a like plurality of rollers  178 . As shown in  FIGS. 6A and 6B , chain guide mechanism  172  includes top and bottom plates  180  spaced apart by a spacer member  182  having side edges  184  and arcuate end faces  186 . The mechanism  172  further includes first and second sprockets  188  and  190 , which are pinned at  192  and  194  to plates  180 . It should be appreciated from  FIG. 6B  that the thickness of the spacer plate  182  is greater than the sprocket thickness, such that clearance is formed intermediate the plates  180  to allow sprockets  188 ,  190  to rotate therein. It should also be appreciated that the arcuate end faces  186  form arcuate pockets to receive the sprockets  188  and  190 . With reference again to  FIG. 6A , it should also be appreciated that the side edges  184  of the spacer plate  182  are recessed within the spacer plates  180  so as to form a recess  198  for receiving chain link  174 .  
      With respect again to  FIG. 5 , mounting arms  176  include flange portions  200 , which are connectable to chain link  174  by fasteners such as  202 . Rollers  178  are also interconnected to rod ends  204  by way of a pivot joint at  206 . It should be understood that rods  204  extend in a generally vertical sense, and rollers  178  are attached to rods  204  at a substantially perpendicular angle relative thereto, while pivot joints  206  allow rollers  178  to be mounted to arms  204  in various fixed rotational positions as will be described herein. The rollers  178  are held to pivot joints  206  by way of laterally extending arms  208  and axle  210 . As shown in  FIG. 5 , the roller mechanism is installed such that chain drive mechanism  172  is at a slight angle relative to horizontal, that is, on center line  212 .  
      With respect to the drawing figures, the assembly of the apparatus will now be described. As mentioned above, the sub-frame of the device is comprised of a plurality of horizontal beams  42  and  44  together with vertical legs  40 . It should be appreciated that this frame member is assembled in an elongate fashion so as to provide rigid support for the support track mechanism  6 . The individual rollers  60  and  64  ( FIGS. 2 and 1 E) are positioned to horizontal beam  42 . The plurality of guide members  90  are now positioned relative to the sub-frame  8 , such that slide surface  96  forms a substantially horizontal reference surface. Once the reference surface is established, the individual links  72  ( FIG. 3 ) are connected together and fed around rollers  60  and  64 . As shown in  FIG. 3 , the low friction slides  86  are also slidably received by way of the T-slot  88  slidably received over the T-shaped bar  82 , and the completed chain is positioned around both rollers  60  and  64  so as to form a closed loop. As shown in  FIG. 2 , this positions the low friction slides  86  on top of the slide surface  96  in a sliding relation thereto. It should be appreciated that the complementary surfaces  78 A and  80 A,  FIG. 3 , are profiled such that the links form together a uniform horizontal surface defined by the upper surfaces  76  of the links  72 , and the cooperating surfaces  78 A and  80 A form a closed gap without a raised edge.  
      With reference now to  FIG. 4 , the pressure roller track  34  is now installed in a similar manner as that described with relation to the drive roller  6 , by mounting rollers  100  and  102  to horizontal cross bar  106 . The links  72  and slide  90  are positioned in a similar manner as that described above, while at the same time it should be appreciated that rollers  100 ,  102  should be vertically adjustable so as to adjust the gap distance  110 .  
      The manufacture of composite wall board will now be described. With reference first to  FIG. 2 , a MYLAR roll  300  is installed intermediate arms  46 , with an individual sheet  302  of the roll being fed around tension rollers  54 ,  56  and thereafter placed over the top of links  72 . The MYLAR sheet continues to be fed through oven  14 , as well as through first and second applicators  16 ,  24 , and under rolling stations  22 ,  30 . The MYLAR sheet  302  is then fed through tension roller mechanism  152  and finally to a take-up roll  304  ( FIG. 1E ). It should be appreciated that take-up roll  304  may now be driven simultaneously with rollers  60 ,  64 , whereby MYLAR sheet moves from the left to right as viewed in  FIG. 1A , whereby the MYLAR sheet is supported in a perfectly planar manner by the plurality of links  72 , which move with the MYLAR sheet at the same speed.  
      With reference now to  FIG. 1A , the process may begin by activating spray apparatus  10  such that a gel coat material is sprayed on top of the MYLAR sheet as it passes beneath the spray apparatus  10 . The MYLAR sheet, together with the film of gel coating, now progresses through oven  14 , whereby the gel coating is substantially cured. As the MYLAR sheet together with the gel coated film exits the oven  14  as shown in  FIG. 1C , a resin is sprayed on top of the gel coating through resin spray head  18  and thereafter fiberglass strands are dropped on top of the resin film. Roller mechanism  170  is now operated such that the plurality of individual rollers  178  roll the fiberglass strands into the resin to remove pockets of air from the fiberglass to form a suitable bond with the resin. As shown in  FIG. 5 , the roller mechanism  170  should be adjusted vertically such that the weight of the rollers alone is pressed against the composite of gel coating, resin and fiberglass strands, and the chain  174  is driven by one of the sprockets  188  or  190  so as to move the rollers  178 . The design of the roller mechanism  170  not only provides for uniform rolling of the fiber strands into the resin, but the roller mechanism allows the rollers  178  to move relative to, and at the identical speed of, the MYLAR film, as described with reference to  FIGS. 7A and 7B .  
      With reference first to  FIG. 7A , chain guide  172  is shown as being positioned at an angle Φ 1  relative to MYLAR film  302 , which passes therebeneath. Thus, as the rollers  178  move in the direction of the arrows, rollers  178  move in a transverse direction relative to the movement of the MYLAR film  302 . As the chain guide  172  is mounted at an angle relative to MYLAR film  302 , as shown in  FIG. 7A , the movement of rollers  178  includes displacement components in both the X and Y directions. Said differently, and with reference still to  FIG. 7A , angle Φ 1  is chosen together with the speed of the chain, such that during the time that roller  178 A moves to position  178 C, its displacement is X 1 . Therefore, the displacement of the MYLAR sheet during that same time period would also move a distance X 1 . This prevents the dragging of the rollers, or the relative movement of the rollers in relation to the MYLAR film. In the event that the MYLAR film needs to operate at a higher speed, the chain guide  172  could be configured as shown in  FIG. 7B  mounted at angle Φ 2  relative to MYLAR film  302 . Thus, in this manner, movement of the rollers  178  from the position  178 A to the  178 C position causes a displacement in the X direction of X 2 , which is substantially larger than X 1 . With reference again to  FIG. 5 , the chain guide  172  is also mounted at a tilt angle  210 , which causes rollers  178  to roll on one side thereof, but when the rollers move beyond the edge of the MYLAR film  302 , they are lifted and carried over the top of the MYLAR film.  
      It should be appreciated that after MYLAR film  302  passes beneath the second roller station  30 , the MYLAR film enters area  302 , where an operator can lay the individual panels of wood sheets in a side-by-side manner. As mentioned above, these sheets are typically referred to as luan, and exist in 1.2×2.4 meter (4 ft.×8 ft.) sheets. Thus, the 2.4 m (8′) length would correspond with the 2.4 m (8′) width of the MYLAR film, whereby the panels are abutted together along their side edges. Normally a strip of webbing is placed along the seams of the luan sheets, and the combination of the MYLAR film, the gel coating, the resin, the fiberglass strands, and the luan sheets would now pass under the pressure roller section  34 , whereby links  72  would press against that composite. Depending upon the pressure required, the weight of the links  72  alone may be adequate, while in other instances, it may be required to lower the rail  90  so as to increase the pressure between the opposed links  72 . In any event, it should be appreciated that both the links  72  of the pressure mechanism  34 , the links  72  of the roller drive mechanism  6 , as well as the MYLAR film  302 , are moving at the identical speed. As shown in  FIG. 1E , the MYLAR film  302  is taken up in roller  304 , whereby the composite sheet would be fed onto a roller table  320  in a continuous fashion. It should be appreciated that the continuous sheet could then be cut at downstream locations to any size desired. Furthermore, a continuous reinforcement backing may be provided, so the seams of the lauan product are eliminated. Such a backing may comprise a composite sheet, polymer sheet, foam, coiled steel or aluminum, or other backing having the desired properties for a particular application.  
      Advantageously then, the above-mentioned method and apparatus eliminate the requirement for molds at all, as well as their maintenance. Rather, the above-described apparatus utilizes MYLAR film as the mold surface rather than an elongate mold as described in the prior art. Furthermore, as the sheet which projects onto roller table  320  is continuous, any length of sheet is possible without having scrap lengths to discard.