Abstract:
A method of producing a composite laminate comprises the steps of feeding ground reclaimed material, for example carpet backing, to a dispersing station ( 16 ), dispersing the reclaimed material on a moving web ( 10 ), bringing an intermediate web ( 20 ) into engagement with the layer of reclaimed material, melting the reclaimed material to fuse the reclaimed material to the intermediate web, passing the laminate through compression rollers ( 28, 30 ) to control the thickness of the laminate, and cooling the laminate. The moving web ( 10 ) may comprise carpeting material in which case the melted reclaimed material is fused to the carpeting material ( 10 ) and intermediate web ( 20 ).

Description:
[0001]     This invention relates to a method and apparatus for manufacturing composite layered sheets or tiles from reclaimed waste carpet materials and the like.  
         [0002]     Historically, extrusion processes have been used to produce multilayered composite sheets from reground materials, fiber waste, and/or virgin materials. An extrusion process requires that a high quality consistent material be fed into the extruder to obtain a quality sheet product. Extrusion processes are sensitive to variations in material, bulk density, flow times and melt indices. These variations affect the material flow which can either starve or flood the screw resulting in variations in the extruded sheet in width, thickness, line speed, tensile strength, and surface tension, among other things.  
         [0003]     The present invention provides a method for manufacturing composite layered sheets or tiles from reclaimed materials which is less sensitive to the quality and consistency of the input material than an extrusion process.  
       SUMMARY OF THE INVENTION  
       [0004]     Briefly, in accordance with the invention, a method of producing a composite laminate comprises the steps of feeding ground reclaimed material to a dispersing station, dispersing the reclaimed material on a moving web, bringing an intermediate web into engagement with the layer of reclaimed material, melting the reclaimed material to fuse the reclaimed material to the intermediate web, passing the laminate through compression rollers to control the thickness of the laminate, and cooling the laminate.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a partially schematic illustration of an apparatus and process for producing composite layered sheets and/or tiles from reclaimed waste carpet materials in accordance with a preferred embodiment of the invention; and  
         [0006]      FIG. 2  is a sectional view of a composite layer sheet produced in accordance with the invention. 
     
    
     DETAILED DESCRIPTION  
       [0007]     U.S. Pat. No. 6,029,916 of White discloses a method and apparatus for reclaiming backing and fiber materials from waste carpet or the like. U.S. Pat. No. 6,029,916 is hereby incorporated by reference into this specification.  
         [0008]     The apparatus and process disclosed in the &#39;916 patent produce granulated reclaimed backing material together with fiber waste products. The present invention uses the reclaimed backing material to produce various different types of sheets, including single layer sheets and composite layered sheets or tiles which can be used in the carpet, auto and/or construction industries as well as others.  
         [0009]     The process is described with reference to  FIG. 1  which is a partially schematic illustration of an apparatus for producing a multi-layered composite material. For purposes of this description, the invention is described in connection with the production of a four-layer composite carpet tile.  
         [0010]     Referring to  FIG. 1 , a roll of carpet fiber material is shown at  10 . Any other material can be used. This material may form the visible or upper surface of the carpet and is provided without a backing.  
         [0011]     The carpet fiber material is fed as a web to an endless conveyor belt  12  which conveys the carpet fiber web through the various operating stations of the apparatus. The carpet feed station may be a simple carpet unwind station (e.g. form Menzel Corporation) or it may consist of a sew-in station, accumulator and/or a J-box/scray to allow time to splice rolls of fabric, carpet, etc. together to allow uninterrupted flow. The first station comprises a mixer or blender  14  which combines the reclaimed materials (e.g. from hopper  294  of the &#39;916 patent) with virgin material (if necessary) and other additives (such as coloring agents) according to a specified “recipe”. The reclaimed backing material and other input materials may be fed to the mixer by a conventional material handling system such as a Flexicon auger system, conveyor belt, or vacuum (e.g. the vacuum system from Process Control Corp).  
         [0012]     The blended material within the mixer  14  is dispersed by gravity onto a displacement roller at a scattering station  16 . A suitable mixer and scattering unit is sold by Schott &amp; Meissner Co. The scattering station  16  places the granulated material from mixer  14  onto the fiber web  10  as it moves with the conveyor belt  12 . The scattering rate is a function of the final product specifications and depends on the desired thickness of the product and the line speed. The materials can be preblended off line and/or a volumetric or gravimetric blender can be added to feed the scattering unit if needed.  
         [0013]     In one practical embodiment, a tufted carpet fiber may be conveyed past station  16  at a belt speed of about 1.5 meters per minute. For a reclaimed carpet tile, scattering may be at a rate of about 0.5% per minute. The percent of volume is based on the quantity measuring means of a Schott and Meissner (1 meter) scattering unit. If a single layer sheet, for example 1.1 mm thick, is to be produced, the material from station  16  can be scattered directly onto the belt  12  at a rate of 0.6% per minute.  
         [0014]     The web is then passed through an infrared heating station  18  which preheats the reclaimed material prior to the melting and fusing stage described below. In the example described above, an infrared heater from Glenro, Inc. set to a temperature of 100-110° C. was used.  
         [0015]     In the illustrated embodiment, a laminate feed station is provided. In this station, an intermediate sheet such as a fiberglass sheet  20  can be introduced to the laminate. Any other intermediate sheet such as a prelaminated sheet or a woven reinforced sheet may also be used. Typically, the intermediate sheet functions as a reinforcement to enhance the strength of the final product. Its incorporation at this stage of the process avoids the need to use separate machines for each step in the production of a composite sheet. The laminate feed station includes suitable control rollers which bring the intermediate (fiberglass) sheet  20  into engagement with the preheated layer of reclaimed backing material on the fiber web  10 .  
         [0016]     From the laminate feed station, the three layer laminate is introduced to an oven which includes a calibration roller  22  which is preset for each product specification. The roller gap depends on the heat, time of contact and pressure and ensures an even distribution of the reclaimed material over the desired width of the web. For carpet tile, the precalibration roller may be compressed to a gap of 4.0 mm up to 8 mm specific to the thickness or sculpture in the top layer  10 . For the single layer sheet, the setting may be 1.3 mm. The oven may comprise a Thermofix contact heat oven from Schott &amp; Meissner or a Glenro laminating oven. An endless belt (not shown) keeps the material level and even as it moves through the oven.  
         [0017]     After the precalibration, the material enters the heating section of the oven where heat is applied through heat plates  24  positioned as shown above and below the conveyor belt  12 . The ability to apply heat from the top independently of the heat applied by the bottom plates through the conveyor belt allows multiple formulas for multiple product configurations. The number of heaters used depends on the final product specification. For carpet tile, the top heating units may be at 220° C. and the bottom heating units at 0° C. Three units are used for a one meter wide laminate. For the single layer sheet, both top and bottom heaters may be set at 220° C.  
         [0018]     During this heating stage, which melts and fuses the reclaimed material to the fiber web  10  and the intermediate (fiberglass) sheet  20 , the gasses and smoke produced are exhausted through a vent  26  and ducted to an acceptable point of discharge.  
         [0019]     After the laminate has been fused it is passed through two pairs of calibrated compression or nip rollers  28  and  30  which are used to complete the desired thickness setting while the material is still soft. The setting on the calibration rollers  28 ,  30  corresponds to that of the precalibration roller  22 . If desired, the upper roller(s) can be engraved in order to emboss the product to meet the specification of a particular customer.  
         [0020]     After final compression by the nip rollers  28 , 30 , the laminate flows through a group of parallel cooling plates  32 . The cooling plates are cooled by an exterior chilling system for exact temperature control and can be controlled independently to permit flexibility for a wide range of product specifications. A cooling range between 10 and 15° C. may be used.  
         [0021]     In the illustrated embodiment, the three layer composite is then fed through a second laminating process which is the same as the process described above. Thus, another layer of reclaimed material can be introduced to the three layer laminate by means of a second mixer  34  and scattering station  36 . In this case, the reclaimed material is deposited on top of the intermediate (fiberglass) web  20 . It is then preheated by infrared heaters  38  and, if desired, aligned with a further intermediate sheet in a second laminate feed station. In the illustrated embodiment which consists of four layers only, a second intermediate laminate is not employed. The four layer laminate is then passed through a second oven which also includes a calibration roller  42 , heating plates  44 , calibration rollers  48 , 50  and cooling plates  52 . The composite laminate which exits from the second oven thus consists of four layers, namely the carpet fiber web  10 , reclaimed material, intermediate (fiberglass) web  20 , and reclaimed material. (see  FIG. 2 )  
         [0022]     By way of further example, when a second laminating process is employed, the reclaimed material may be deposited at a rate of 0.5% per minute on top of the intermediate (fiberglass) web  20 . The infrared heaters  38  may be set at approximately 110° C. In the second oven, calibration roller  42  may be set at 0.5 mm. The heating plates  44  may be heated to a temperature of 200° C. with the bottom heating units at 0° C.  
         [0023]     The finished product can then be passed to an accumulator  54  and then sized and packaged in station  56  in a conventional way.  
         [0024]     In the preferred embodiment, the operator has the capability of determining the formula for the reclaimed material (i.e. the percentage of reclaimed material, virgin material and other additives), the lines speed, heat, pressure and thickness in order to create a final composite product such as carpeting, carpet or plastic floor tiles, liner materials, mats of all description, awnings, billboards and numerous other products. Typically, the reclaimed material comprises polyvinyl chloride, rubber, polycarbite waste or nylon fiber.