MXPA06001344A - Method for recycling carpet and articles made therefrom - Google Patents

Abstract

In one embodiment, the method for recycling carpet can comprise decreasing an average size of the recycle carpet to form a processed carpet, wherein a bulk density of the recycle carpet is changed by less than or equal to about 15%during the decreasing. The processed carpet can be shear mixed and melted to form a melt ribbon which can be processed in a vented extruder to form an extrudate. Optionally, the extrudate can be pelletized.

Description

U N M ETHOD FOR RECYCLING CARPETS AND PRODUCTS THEY MADE OF THEM REFERENCE TO RELATED REQUESTS This application is a continuation of U.S. patent application n umber 10 / 279.443, filed 24 ber 2002, which claims priority to provisional patent application serial number US 60/334, 900, filed 24 ber 2001, whose full content of both is incorporated in the present application as reference.

BACKGROUND OF THE INVENTION This description refers to the recycling of carpets, and also refers to the manufacture of articles from recycled carpets. The use of synthetic fibers has increased in many areas of technology, including various types of carpeting and other floor coverings. Increased carpet production, however, creates the problem of what to do with used carpets after their useful life ends. Significant efforts have been made to identify environmentally responsible methods for disposing of floor covering material. However, an obstacle to the successful recycling of carpets is the fact that the carpet is currently manufactured from a number of different synthetic materials that have varying physical and chemical characteristics. For example, conventional carpet materials typically include several layers. The simplest types of carpets may have fibrous hairs (eg, nylon, PET or polypropylene) fused directly to a thermoplastic support, typically polyolefin. There may also be a linker or secondary substrate, reinforcing mesh material through which the hair is attached, and / or a separate adhesive used to anchor the hair to the substrate. The glue may be, for example, styrene-butadiene rubber applied as a latex, loaded with an inorganic filler such as calcium carbonate. Successful attempts to recycle these products with multiple components have been severely limited. Efforts have focused on methods for reprocessing waste materials containing fiber where the process results in a final product containing fiber. However, these types of processes are restricted in their utility to limited application where composite materials (fiber / matrix) are useful. Other recycling approaches have focused on the separation of individual materials for reuse. These methods, while ineffective in recovering individual synthetic materials, are extremely expensive, to such an extent that they are often prohibitively expensive. In addition, the additional energy required to perform the necessary processing steps at least partially reduces the environmental advantage of recycling or reuse. Additional work is needed in the carpet recycling area to allow for effective recycling of carpeting costs on a production scale and not merely on a laboratory scale.

BRIEF DESCRIPTION OF THE INVENTION Methods for the recycling of carpets, methods for making articles with recycled carpets, and articles made from them are discussed here. In one embodiment, the method of recycling carpets may comprise reducing an average size of the recycled carpet to form a processed carpet, wherein a weight per unit area of the recycled carpet is changed in less than or equal to about 15% during the reduction. The processed carpet can be mixed by shear and melt to form a cast strip that can be processed in a vented extruder to form an extrudate. Optionally, the extrudate can be granulated. In another embodiment, the method for recycling carpets may include: melting the recycled carpet in an extruder to form an initial extrudate, mixing with shear in a shear mixer to form a cast strip, processing the cast strip in a vented extruder to form a subsequent extrudate, and optionally granulating the subsequent extrudate. In yet another embodiment, the method for recycling carpets can comprise: reducing an initial average size of the recycled carpet to an average processed size of less than or equal to about 12.7 cm by less than or equal to about 12.7 cm, to form a carpet processed, while the apparent density of the processed carpet is greater than or equal to about 24.0 kg / m3, mixing and melting the processed carpet to form a cast tape, and processing the cast tape in a ventilated extruder to form an extrudate. The features described above and others, are exemplified in the following figures and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the figures, which are intended to serve as examples, not limiting. Figure 1 is a flow chart of one embodiment of a method for recycling carpets. Figure 2 is a flowchart of another embodiment of a method for recycling carpets.

DETAILED DESCRIPTION Recycled carpets can be made into a suitable material for use, for example, in various molding processes (eg, blow molding, injection molding, and the like). The carpet can be used to form various articles, including leach chambers, for example, to disperse liquids in the soil, of the type having a hollow interior with open ends and an open bottom allowing the passage of liquids through it; end plates for use with a leach chamber for dispersing liquids in the soil, of the type having a hollow interior with open ends, and side walls with perforations that allow liquids to pass through them, and where the final plate comprises an inner wall and an outer wall, which define a central portion having an interior channel and optionally at least one connector capable of coupling an edge of a leach chamber, with physical contact with both an interior surface and an exterior surface of the leach chamber, pallets and the like. Figures 1 and 2 provide flow diagrams of modalities of the general method and apparatus that can be used to recycle carpets. The carpet, for example, in the form of a carpet bundle or the like, can optionally be placed in a shredder, and where the carpet has an initial weight per unit area as it enters the shredder 1. The resulting carpet strips can then be fed to the cutters 3.5. From the cutters 3.5, the carpet can enter the shear mixer 7, where the cut carpet entering the shear mixer has a cut carpet bulk density. The shear mixer 7 melts the cut carpet and reduces any moisture in it to produce a molten carpet. From the shear mixer 7, the molten carpet enters an extruder 9. Additives, plastic and the like can also be introduced into the shear mixer 5 and / or into the extruder 9. From the extruder 9, the extruded material may be granulated 1 1 or directed to further processing (eg, introduced to a molding apparatus (not shown) The carpet may contain any available main material (eg, polyethylene terephthalate). ), polypropylene, nylon carpet, and the like) with any hair weight, for example, a post-consumer or used carpet can be used, for reasons of economy, availability and environmental considerations. Unacceptable carpet for sale, cutting waste (from carpet production), and / or carpet returned by the buyer.In addition, the carpet can be in any number of physical conditions, including dirty, wet, stained, treated for resistance to stains, clean, and the like, as well as in combinations that comprise at least one of the preceding conditions. For economy of shipping, space and sim illary, the carpet may be in the form of bales that may contain any number of different types of PET, polypropylene and / or polyethylene carpets, and the like, for example, carpets of different origins, different physical properties, different chemical properties and similar. Unlike many methods for carpet recycling, carpets may not be separated, that is, the carpet that has not been modified to imitate or separate one or more of the primary components of the carpet (hair, support, adhesive, etc. ), before processing. Although a carpet sample in a non-separate package may be more cost effective, separate carpets, or portions thereof, may be used. In other words, if for example hair (for example, fibers) has been reused in another process, the substrate and other remaining carpet components can be used. Typically the carpet will contain hair, a substrate, an adhesive and a filler. The hair and the substrate often contain a thermoplastic material, such as polyolefin, polyester, nylon and the like, as well as combinations containing at least one of the preceding materials. The adhesive used to adhere hair to the substrate may contain a latex material, other adhesives, and the like, such as styrene-butadiene rubber (SBR), acrylate resins, polyvinyl acetate, and the like, as well as combinations containing at least one of the preceding adhesives. Finally, the bulking agent, for example, can comprise calcium carbonate, as well as other bulking agents that are used with thermoplastic materials. The carpet may contain a main material and optionally additives, and the like. Generally, the carpet contains more than or equal to about 50 percent by weight of main material (e.g., PET, polypropylene, nylon or the like), or more specifically, more than or equal to about 70 percent by weight of main material. , and even more specifically more than or equal to approximately 80 percent by weight of main material, based on the total weight of the carpet excluding the weight of the water. The carpet may also contain more than or equal to about 5 weight percent latex material, may contain less than or equal to about 20 weight percent more or less of flame retardant, and may contain less than or equal to about 10 percent by weight of calcium carbonate (e.g., about 0.5 percent by weight to about 10 percent by weight). In an exemplary embodiment, a carpet may contain about 80 percent by weight of main material (e.g., PET, polypropylene, nylon or the like), about 10 percent by weight to about 15 percent by weight of latex material, and less than or equal to about 10 percent by weight of calcium carbonate, based on the total weight of the carpet including the weight of the water.

In order to achieve a desired product from recycling, various additives can be added to the carpet. The quantities and types of additives used are based on the composition of the carpet and the use of the product. For example, recycled carpet can be formed into granules that are useful in the injection molding of plastic articles (e.g., pallets, leach chambers, end plates and the like). Some of the shades can be tested (for example, by using a spectrometer, measuring the melted temperature, and / or the like) to determine their composition. For example, the melt index can be determined to clarify the amount of additives that one wishes to introduce into the recycled carpet. The amount of additives can be about 0.3 percent by weight to about 40 percent by weight, or more specifically, about 0.5 percent by weight up to about 20 percent by weight, or even more specifically, about 1 percent by weight up to about 10 percent by weight, and still more specifically, about 1 percent by weight up to about 5 percent by weight, based on the combined total weight of the carpet and additives, and including the weight of the water (e.g., the weight combined total). Exemplary additives include colorants, stabilizers (e.g., gloss stabilizers, heat stabilizers and others), delusterants, flame retardants (e.g., ATH and the like), bulking agents, antimicrobial agents, antistatic agents, brighteners. optics, rheology controllers, fusion enhancers, desiccants, extenders, processing aids, compatibilizers, flow improvers, mold release agents, UV absorbers, lubricants, plasticizers, pigments, dyes, blowing agents, impact modifiers and other additives that impart desired properties to the product. For example, the additives can be PET in an amount of about 2 percent by weight to about 5 percent by weight based on the combined total weight, and an impact modifier that can be employed in an amount of about 5 percent. by weight up to about 10 percent by weight based on the combined total weight. Bulking agents may be employed, such as aluminum silicates such as hydroxyl, mica, feldspar, clays, talc, glass (e.g., flakes, fibers, microspheres, nanotubes and the like), wollastonite, metal oxides (e.g., alumium, dioxide) titanium, silica, zinc oxide and the like), zinc sulphide, natural quartz, barium sulfate, glass fiber, and the like, as well as combinations containing at least one of the preceding fillers, to obtain stability thermal, rigidity, texture and other desired qualities. For example, the bulking agents may comprise clays, talcum, calcium carbonate and the like, as well as combinations comprising at least one of these bulking agents in amounts of about 5 weight percent to about 10 weight percent. , based on the combined total weight. The processing of the carpet may include reducing the size of the carpet, for example, to decrease the melting times and to facilitate a constant flow of carpet in the shear mixer 7 and / or in the extruder 9. With the In order to allow the maintenance of a sufficient flow rate of the carpet in such a way that the process is efficient on a production scale, the size of the carpet can be reduced to an average processed size of less than or equal to approximately 12.7 cm. for less than or equal to about 12.7 cm, or more specifically less than or equal to about 7.62 cm per less than or equal to about 7.62 cm, or even more specifically, less than or equal to about 5.08 cm per less than or equal to at about 5.08 cm, and still more specifically, less than or equal to about 3.81 cm by less than or equal to about 3.81 cm. In addition to the reduction in size of the carpet, the weight per unit area of the carpet can be maintained substantially at its original (ie initial) weight per unit area. From the moment the carpet is received in the shredder (with its initial weight per unit area) until the carpet comes out of the cutters (with its weight of carpet cut per unit area), it is desirable to change the weight per one surface area of the carpet in less than or equal to about 15% or more specifically, in less than or equal to about 10% or, even more specifically, in less than or equal to about 5%, and still more specifically, in less than or equal to about 3%, where the change in weight per unit area can be determined by subtracting the weight of the cut carpet per unit area, from the initial weight of the carpet per unit area , and then dividing the result by the initial weight of the carpet per unit area. Any sequence of cutting processes that reduce the size of the carpet to a desired size while preventing the carpet from becoming lint can be employed. For example, the carpet can be processed first through an optional shredder 1 that can reduce the carpet to an average size of less than or equal to about 76.2 centimeters, or more specifically, less than or equal to approximately 61cm. and even more specifically, less than or equal to about 30.5 cm, measured along the main axis (ie, the longest). Desirably, when the shredder 1 is used, the folder passes through the shredder 1, for example, leaving some material finely shredded and some in longer strips. In one embodiment, for reasons of having a sufficient weight for a surface area and for efficiency, the carpet is desirably only passed through the shredder only once, where only one shredder is used and no mills in the process.

From the shredder 1, the carpet strips can be routed to one or more cutters 3, 5, with an optional hopper disposed between the shredder and the cutter and / or between the cutters (not shown). Each cutter 3, 5, is directed to cut the carpet into smaller pieces without substantial comminution and / or without grinding the carpet (i.e., changing the weight per unit area of the carpet to less than or equal to 10%). The quantity and orientation of the cutters 3. 5 can be chosen in such a way as to further increase the size of the carpet to the size of the melt. For example, two cutters, 3, 5, can be oriented at an angle of about 85 ° to about 95 ° (for example, perpendicular) with one another such that the size of the carpet is reduced to an average melt size wanted. The cut carpet can be introduced into the shear mixer 7 from the cutters 3.5, to melt the carpet, remove moisture, and optionally, to allow the introduction of other material or materials (eg, plastics, additives, and the like). ). For example, in addition to cut carpet, impact modifiers (eg, about 5 weight percent to about 10 weight percent, based on total weight) may be added. The carpet and impact modifier can be mixed and heated at about 177 ° C to about 232 ° C to melt and mix the materials as well as to reduce the water content to less than or equal to about 0.5 percent by weight. The shear mixer 7 can be operated under atmospheric pressure, allowing easy release of moisture from the carpet. If the water content of the cut carpet is greater than 0.5 percent by weight, the water content is reduced to less than or equal to about 0.5 percent by weight, based on the total weight of the carpet (including the water) or more specifically, less than or equal to about 0.25 percent by weight. The melting and mixing can be carried out in any shear mixer capable of achieving sufficient temperatures to melt the carpet and vaporize and ventilate the water. For example, a shear mixer 7 can receive the carpet cut by means of a conveyor (not shown). Within the shear mixer 7, the carpet melts and releases moisture to reduce the water content to less than or equal to about 0.5 percent by weight, thereby forming a cast carpet belt. Optionally, additives may be introduced at this stage, as well as, for example, impact modifiers, flow improvers, moisture absorbers, and the like, as well as combinations containing at least one of the additives described herein. From the shear mixer 5, the molten carpet belt can be introduced to an extruder 9, for example, by means of a feed channel of the extruder, J-shaped block or the like. The extruder, which can also mix the carpet tape and any additives, and optionally can receive additional additives, can be a twin screw extruder, single screw extruder, ventilated extruder (single screw or multiple screws), or Similary. For example, about 2 percent by weight to about 5 percent by weight of PET, about 1 percent by weight to about 5 percent by weight of calcium carbonate, and about 0.05 percent by weight can be introduced into the extruder feed channel. percent by weight to about 0.20 percent by weight of melt improvers, and possibly other additives to the melt, based on the combined total weight of the melt and additives (including water weight). Within the extruder, the carpet tape can be further blended to achieve a substantially homogenous melt mixture. For example, the carpet tape can be introduced to the extruder 9 where it is processed at temperatures of about 4232 ° C to about 288 ° C. Inside the extruder 9, the screw mixes the tape and the additives under pressure as the melting progresses towards a ventilated section. In the ventilated section, which is at atmospheric pressure, the residual moisture in the melt can be released through the vent, before the melt is further mixed and pushed, under pressure, through an extruder nozzle. From the nozzle, the molten mixture can be further processed (eg, molded or otherwise used to form an article), formed into a sheet, or pelletized. For example, the molten mixture can be formed into granules by means of various granulation operations, such as passing the mixture through a nozzle and a cutter (not shown), using a 1 1 underwater granulator and the like. In one embodiment, the melt can be extruded through a 1 1 underwater pelletizer at rates of approximately 2.27 Tm / hr up to approximately 4.54 Tm / hr per hour, depending on the feed weight per unit area, size of equipment, and Similar. In an alternative embodiment, an extruder (eg, a twin screw extruder, ventilated extruder and / or the like) may be used prior to the shear mixer 7. In this embodiment, the mat may be introduced into the extruder directly from the extruder. shredder, and / or from the cutter or cutters.The extruder can initially melt the carpet, can handle fluctuations in the rate of carpet feed, and can produce an extrudate that can be introduced directly into a shear mixer, can be granulate directed through a hopper to the shear mixer (to allow a constant feed rate and to control fluctuations in the rate from the extruder), can be granulated and introduced directly to the shear mixer, and similar, as well as combinations comprising at least one of the above.In the shear mixer the extrudate can be melted back (if in solid form) and optionally mixed with any of all the determined amounts of additives until the viscosity of the cast strip allows a desired flow of the cast strip in the extruder, and the water content of the cast strip it can be less than or equal to about 0.25 percent by weight up to about 0.50 percent by weight, or more specifically, less than or equal to about 0.25 percent by weight, based on the total weight of the carpet, including water. As described above, from the shear mixer, the cast tape can be fed to a ventilated extruder (eg, to a single screw extruded extruder), and then finally processed (eg, granulated, molded and the like). ). The granules can be used alone or in combination with other materials (for example, thermoplastic materials and the like (such as virgin PET, polypropylene, and the like)), in various molding processes, such as blow molding, injection molding (e.g. , high pressure injection, gas assisted, structural foam, and the like), thermoforming, (e.g., pressure forming, vacuum forming, stamping, and the like), extrusion (e.g., sheet extrusion, film extrusion, geometric (for example, tubes and the like), extrusion), and the like, but not limited thereto, to form various articles. Some possible items include leach chambers, pallets, end plates, as well as various other thermoplastic articles. The following examples are for purposes of example, not limitation.

EXAMPLES EXAMPLE 1 PROCEDURE OF RECI CLAJ E WITH FLOW AN IFORM E U EXTRUSO RA DOWNSTREAM The carpet to be recycled was tested to determine the composition of the material, and to determine the moisture level and the melt index. This information was used for the determination of the types and amounts of additives that were to be added to the carpet, for example, based on the desired end use of the recycled carpet, and its water content. (If compatibilizers are not going to be added during the processing of the carpet, the nylon carpet is removed, since it is not compatible with polypropylene). The carpet was then comminuted to a size of approximately 7.62 cm by approximately 30.48 cm, and fed, by means of a conveyor, to a first cutter where it was cut so that it had a dimension that was approximately 2.54 cm (i.e. cm by up to about 30.48 cm). From the first cutter, the initially cut carpet entered a second cutter arranged at an angle of 90 ° with respect to the first cutter, such that the carpet was cut to a second dimension of approximately 2.54 cm (i.e. 2, 54 cm by 2, 54 cm). The cut folder then entered a third cutter that further reduced the size of the carpet. From the third cutter, the binder was introduced, at a constant rate, to a shear mixer where it was cast and mixed with the determined amount of additives until the viscosity of the cast tape was sufficient to allow flow to outside the shear mixer. From the shear mixer, the cast tape was fed directly into the feeder channel of a single screw ventilated extruder. Within the extruder, the tape was further mixed under pressure before entering the ventilated zone of the extruder, where residual moisture escaped from the molten mixture. From the ventilated zone, the molten mixture was further mixed, under pressure, until it exited the extruder through a nozzle and was granulated with an underwater granulator. Without being limited by theory, by maintaining the apparent density of the carpet in a bulk density greater than or equal to 16 kg / m3, the process described in Example 1 allowed the carpet to be recycled efficiently, effectively, and with scale of production, without processing problems. When the carpet is fluffed (for example, it is torn and / or powdered at an apparent density of less than 16 kg / m3, and / or has a weight change per unit area of more than 20%), it may occur the non-uniform introduction of the carpet into the shear mixer. The fluctuation in the flow rate, the introduction of "pegs" of carpet, can overload the mixer, cause pressure fluctuations in the extruder and / or inhibit the proper operation of the granulator, and can result in a line stoppage. Additionally, the lint carpet can jam the channel of the shear mixer, further accentuating the above problems, which can finely give an inefficient process for the production scale. Although apparent densities of approximately 16 kg / m3 can be used, densities greater than or equal to approximately 24 kg / m3 facilitate higher production rates. More specifically, in a production scale, apparent densities greater than or equal to about 32 kg / m 3, or even more specifically, greater than or equal to about 40 kg / m 3 can be used. In other words, desirably, the weight per unit area of the carpet entering the feeder channel of the shredder is substantially the same as the weight per unit area of the carpet entering the shear mixer. During the processing of the carpet, sand and the like can be shaken and dropped from the carpet, so that the weight (and bulk density) may change slightly due to the removal of the sand, but if not, it remains substantially constant. The cutters used here can have an effect on the carpet similar to carpet cut with scissors, the size of the pieces of carpet is reduced, but the other properties, for example the weight (ie, kilos per square meter) remain equal. .

EXAMPLE 2 P ROCESS OF RECYCLE WITH EXTRUDER BEFORE D E LA CUTTING EFFORT MIXER The carpet that is going to be recycled can be tested to determine the composition of the material, and to determine the moisture levels and the melt index. This information can be used to determine the types and amounts of additives that are to be added to the carpet in the shear mixer. Again, if you are not going to add compatibilizers during carpet processing, you can remove the nylon carpet. The carpet can then be shredded, cut, and fed directly into a double-screw ventilated extruder. The extruder may initially melt the carpet, can handle fluctuations in the feed rate of the mat and can produce an extrudate which can be introduced directly into a mixing shear, can be granulated and directed through a hopper into the mixer shear (to allow a constant feed rate and to control fluctuations in the extruder rate), it can be granulated and fed directly into the shear and similar shear mixer, as well as combinations comprising at least one of the above. In the shear mixer the extrudate can be melted again (if it is in a solid form) and optionally mixed with the amount of additives determined until the viscosity of the cast strip is sufficient to allow the cast tape to be moved from the mixer to the extruder. Also, the moisture content of the cast tape can be reduced to less than or equal to about 0.5 percent by weight based on the total weight of the extrudate (including water). From the shear mixer, the cast strip can be fed directly to the feeder channel of a second extruder (eg, to a single screw, ventilated extruder). Optionally, additives can also be fed into the second extruder. Within the second extruder, the belt can be further mixed under pressure before entering the vent zone of the extruder where residual moisture can escape from the molten mixture. From the ventilation zone, the molten mixture can be mixed further, under pressure, until it can leave the extruder through a nozzle and be granulated or otherwise processed.

EXAMPLE 3 A loading cam ion bale carpet is randomly sampled (for example, three bales truckload and some material from each of the three bundles are selected is analyzed with respect to their material composition, content and index of fusion). For example, the filler may include polypropylene carpet q ue contains 84 percent by weight polypropylene, January 1 percent by weight latex, and calcium carbonate moiety, with a moisture content promed iando 8 percent by weight and a melt index of 3. The bales can then be shredded to allow the material to be fed into the mixer. Based on the composition analysis, impact modifiers (eg, 1.0 percent by weight) can be added to the carpet in the feeder channel of the shear mixer. The material can be processed in the mixer shear at 193 ° C in a homogeneous mixture of carpet and impact modifier, while excessive water content is removed (turning water into steam and fanning out of the mixer) until The residual water content is less than 0.5 percent by weight based on the total weight of the carpet, including water. The mixture can then be fed directly into the feed channel of an extruder together with 3 weight percent to 7 weight percent PET and processed at 232 ° C to mix and bind the materials for introduction into an underwater granulator for conversion in granules.

EXAMPLE 4 A bottom plate can be formed for use with a leach chamber to disperse liquids in the soil using the recycled carpet. The recycled carpet can be melted without separating various layers of carpet. The water content of the carpet entering the shear mixer may be up to 10 percent by weight or exceed this figure, based on the total weight of the carpet entering the shear mixer ( including water). The water content of the recycled carpet is reduced to less than or equal to about 0.5 percent by weight within the shear mixer based on the total weight of the recycled carpet and water, as discussed in Example 1 , to form a cast tape. The cast tape, properly examined for removal of contaminants, can be mixed with an additive to form a preliminary shape. The preliminary form can be placed, for example extruded, between mold halves and one end of the preliminary shape can be closed. An inert gas can then be blown in the preliminary form to form a balloon and the mold halves can be closed to form the bottom plate. The bottom plate may comprise any suitable geometry for bottom plates, for example, an inner wall and an outer wall defining a central part having an inner channel, and at least one connector arranged on the periphery of the central part, The connector is capable of being coupled to the leach chamber.

EXAMPLE 5 A leaching chamber can be formed to disperse liquids in the soil, of the type that has a hollow interior with open ends and an open bottom that allows the passage of liquids through it, from the molten ribbon or the granules of recycled carpet. Recycled carpet can be melted without separating the various carpet layers. The water content of the recycled carpet can be reduced to less than or equal to approximately 0.5 percent by weight, based on the total weight of the recycled carpet, converting the excess water into steam and venting the steam out of the mixer. The reduced material in water can then be fed in an extruder. An additive can be mixed with the melted ribbon to form a mixture that can be extruded to form granules. The granules can be heated to melt and introduced into a mold having a negative of the leach chamber. Once the melting has cooled, either actively or passively, the leach chamber can be removed from the mold.

EXAMPLE 6 A plastic article can be produced by extruding a flat sheet made of cast tape or the recycled carpet granules and then creating the geometry of the article through a thermoforming or stamping process. The granules can be produced first as in Example 3. The molten ribbon granules are fed through a line for sheet extrusion having an extruder to melt the granules (or the ribbon), sheet matrix (for distribution of the melt for forming the sheet), calendering (crushing, calendering, dimensioning the sheet, initiating cooling), cooling step (typically a water bath), and a cutting station or tension adjusting roller (depending on the thickness of the sheet or end use). The sheet is then heated and formed by stretching (vacuum thermoforming), pressing (thermoforming by pressing) or compressing (stamping) the sheet in a tool containing the negative of the geometry of the plastic article. Once the melt has cooled, either actively or passively, the plastic article can be removed from the mold. This process can be used to form a plastic palette or a component of it. Granules of recycled material, which may or may not contain additives, can be combined with virgin material, such as polypropylene, high density polypropylene, PET, nylon and the like (for example, recycling of materials other than carpet), when an article is formed. For example, granules can be used to form an article in an amount of about 0.1 percent by weight to about 100 percent by weight of recycled material (ie, the granule reformed into the desired article), based on the total weight of the article. . The specific amount of the recycled material will depend on the requirements of the current article. For example, for a leach chamber, end plate, and the like, more than or equal to 50 percent by weight of recycled material, more than or equal to about 90 percent by weight of most preferred recycled material, can be used, and more than or equal to 95 percent by weight of specially preferred recycled material. For a pallet (for example a plastic pallet), approximately 5 percent by weight up to about 40 percent by weight, or more than recycled material, or more specifically, about 15 percent by weight up to about 25 percent by weight can be employed. of recycled material, based on the total weight of the recycled composition in the plastic pallet. Previously injection molding of recycled polypropylene carpet had not been successful due to: 1) water content of the carpet, 2) the perceived need to produce pure polypropylene granules, which required significant material separation, and 3) the fractional melt index of recycled carpets (for example, the polypropylene used to make carpet fibers typically has a melt index of less than 2). While fractional mergers are desirable for some molding processes, such as sheet extrusion (typically fractional melting range up to 4), fractional fusions are not desirable for blow molding (typical melt index 2 to 6) and injection molding (typical melt index greater than about 6). It has been found that by reducing the water content and mixing the correct amount of additives to alter the melt index, the appropriate granules can be formed even from recycled carpets that have not been separated into their various constituents (eg, hair, adhesive, substrate, etc.). The process described actually allows the recycling of carpets that may be saturated with water (for example, that were under the rain). A granulate can be formed using the process described, having reduced water content to less than 2 percent by weight, or more specifically, less than or equal to approximately 0.5 percent by weight and even more specifically, less than or equal to about 0.25 percent by weight, based on the total weight of the granulate, including any water. Additionally, a melt index greater than or equal to about 2, or more specifically, greater than or equal to about 4, and even more specifically, greater than or equal to about 6. The terms "first", "second", and similar here do not denote any order, quantity or importance, but are used to distinguish one element from another, and the term "a" here does not denote a quantity limitation but denotes the presence of at least one of the referred element. The "about" modifier used in connection with a quantity is inclusive of the indicated value and has the meaning dictated by the context (for example, it includes the degree of error associated with the measurement of the particular quantity). All the scales described here are inclusive and combinable (eg scales of "up to about 25 percent by weight, or more specifically, about 5 percent by weight to about 20 percent by weight", is inclusive of the points ends and all the intermediate values of the scales of "approximately 5 percent by weight to approximately 25 percent by weight", etc.). While the invention has been described with reference to an exemplary embodiment, those skilled in the art will understand that various changes can be made and equivalents can be substituted by elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Accordingly, it is understood that the invention is not limited to the particular embodiment described as the best form contemplated for carrying out this invention.

Claims (9)

1. REVIVAL NAME IS
2. 1 . A method for recycling carpets, which comprises: reducing the recycled carpet to an average processed size of less than or equal to about 12.7 cm by less than or equal to about 12.7 cm, to form a processed carpet, characterized by changing a weight per unit area of the recycled carpet for less than or equal to approximately 15% during the reduction; mix with shear and melt the processed carpet to form a cast ribbon; processing the cast tape in a vented extruder to form an extrudate; and granulate the extrudate. The method of claim 1, further characterized in that reducing an initial size of recycled carpet further comprises cutting the carpet in a series of cutters.
3. 3. The method of claim 2, further characterized in that it comprises stripping the carpet before cutting the carpet.
4. 4. The method of claim 2, further characterized in that a flow of carpet cuts from a first cutter in the series of cutters enters a second cutter in the series of cutters at an angle from about 85 ° to about 95 °.
5. 5. The method of claim 1, further characterized in that the average processed size is less than or equal to about 7.62 cm by less than or equal to about 7.62 cm.
6. 6. The method of claim 5, further characterized in that the processed average size is less than or equal to about 5.08 cm by less than or equal to about 5.08 cm.
7. 7. The method of claim 1, further characterized in that the weight per unit area is changed by less than or equal to about 10 percent.
8. 8. The method of claim 7, further characterized in that the weight per unit area is changed by less than or equal to about 5 percent.
9. 9. The method of claim 1, further characterized in that prior to mixing with shear, the processed carpet is melted in an extruder. The method of claim 9, further characterized in that it comprises granulating the processed carpet before mixing with shear. eleven . A method for recycling carpets, comprising: melting the recycled carpet into a first extruder to form an initial extrudate; mixing with shear stress the initial extrudate in a shear mixer to form a molten ribbon;

   processing the molten tape in a vented extruder to form a subsequent extrudate; and granulating the subsequent extrudate. The method of claim 11, further characterized in that it comprises granulating the initial extrudate prior to mixing the initial extrudate with shear stress. The method of claim 12, further characterized in that it comprises introducing the initial granulated extrudate into a container, and introducing the initial granulated extrudate into the shear mixer at a substantially constant rate. The method of claim 12, further characterized in that it comprises reducing an average initial size of the recycled carpet to an average processed size of less than or equal to about 12.7 cm by less than or equal to about 12.7 cm, before introducing the recycled carpet in the first extruder, and further characterized in that a weight per unit area of the recycled carpet is changed by less than or equal to about 15% during the reduction. The method of claim 11, further characterized in that it comprises reducing an average initial size of recycled carpet to an average processed size of less than or equal to about 12.7 cm by less than or equal to about 12.7 cm, before introducing the recycled carpet in the first extruder, and further characterized in that when it enters the first extruder, the recycled carpet has a bulk density greater than or equal to about 24 kg / m 3 16. The method of claim 15, further characterized in that the apparent density is greater than or equal to about 32 kg / m3. 17. A method for recycling carpets, comprising: reducing an average initial size of recycled folder to an average processed size of less than or equal to about 12.7 cm by less than or equal to about 12.7 cm, to form a processed carpet, in where an apparent density of the processed carpet is greater than or equal to approximately 24 kg / m3. mix with shear and melt the processed carpet to form a cast tape, and process the cast tape in a vented extruder to form an extrudate. 18. The method of claim 17, further characterized in that it comprises granulating the extrudate. 19. The method of claim 17, further characterized in that the bulk density is greater than or equal to about 32 kg / m3. The method of claim 19, further characterized in that the bulk density is greater than or equal to about 40 kg / m 3.