MX2008003551A - Method of and apparatus for treating particulate materials for improving the surface characteristics thereof - Google Patents

Abstract

Apparatus and a method is disclosed for treating particulate materials (e.g., plastic resins) so as change the surface characteristics of the particulate materials comprising a work chamber receiving a quantity of the particulate material to be treated, a power supply, and a capacitor energized by the power supply, where the capacitor generates a capacitive plasma which is used to treat the particulate material such that when objects are formed from the treated particulate material, such objects will have enhanced surface characteristics. Further, a quantity of a gas may be introduced within the work chamber to facilitate the generation of a plasma within the particulate material.

Description

METHOD AND APPARATUS FOR TREATING CORPUSCULAR MATERIALS TO IMPROVE THE SUPERFICIAL CHARACTERISTICS OF THEM TECHNICAL FIELD This disclosure relates to the surface treatment of corpuscular materials, and more particularly to the surface treatment of corpuscular plastic resins or other corpuscular materials as will be described below in order to improve their surface characteristics before subsequent processing processes, such as molded objects. of said treated resins, such that a wide variety of coatings, adhesives, paints, inks and other materials adhere to the objects made of such treated corpuscular resins, and / or improve the surface characteristics of such objects to improve wettability of surface, lubricity, and surface energy or surface tension.

BACKGROUND OF THE INVENTION Even more specifically, this disclosure relates to the treatment of corpuscular plastic resins to increase the aforementioned surface characteristics of the molded objects of these resins. Although a wide variety of corpuscular materials can be treated by the apparatus and method of the present invention, the process (s) of this disclosure are particularly well suited for treating the surface of natural or synthetic plastic powders, granular, pellet or other forms of particles (ie, any solid or semi-solid polymer material of fusible substance generally recognized as a plastic, a elastomer, or a material similar to plastic). In addition to these polymeric resins, corpuscular materials treated in accordance with the surface treatment systems and methods disclosed herein could include other materials, such as wood particles, cellulose, paint pigments (e.g., titanium dioxide, TIO2) or similar. Furthermore, it will be understood that said corpuscular plastic materials may be a mixture of various plastic resins and additives, such as plastics of various re-ground or recycled resins. Said other corpuscular materials could also be a mixture of plastic particles and other substances such as fillers, fibers, metals, dyes such as titanium dioxide (TIO2), elastomers, plastic, or the like. Often, after a plastic object has been molded, adhesives, paints, inks, and other coatings will not adhere well to the surface of the plastic object. In many cases, it has been necessary to treat the surface of the molded objects to change the surface characteristics of the object so that said coatings and adhesives adhere more easily to the objects. For example, the plastic resins that typically require such surface treatment include polyethylenes of all types, polypropylene, TPO, TPE, and others. With the advent of water-based adhesives, paints and inks, it is often desirable to surface treat molded objects of other plastic resins (eg, styrene, ABS, PVC, engineered plastics, acrylics and polycarbonates) that do not they require, until now, the surface treatment when adhesives, paints and solvent-based inks are used. Said surface treatment subsequent to the molding of molded plastic objects was achieved in different ways. For example, a post-molding treatment method involves exposing the molded object to an open flame to treat the surface of the object. However, such flame treatment required significant amounts of energy (eg, natural gas), may result in warping or shrinkage of objects, and can not be used with flammable plastics. Another post-molding treatment process is a corona discharge treatment process wherein the molded object is exposed to a corona discharge. Nevertheless, the desired surface treatment is only effective on the surface where the properly adjusted corona discharge comes into contact with the part. In addition, the high temperatures of such corona discharge treatment systems can melt, distort, or even burn the object. In addition, such treatment systems after molding included vacuum plasma processing in which the objects are placed in a sealed vacuum chamber which is evacuated at a low pressure, and a selected gas is introduced. The camera is then energized by electricity or magnetism to create gas plasma. Reference can be made to co-assigned U.S. patent 5,290,489. disclosing to the surface treating the inside of hollow plastic objects by creating a vacuum within the hollow object, introducing a conductive gas (e.g., argon or a mixture of argon / oxygen) into the hollow object and passing the object between a pair of electrodes to ionize the gas within the hollow object to treat the internal surfaces of the hollow object. Lectro Engineering Company of St. Louis, Missouri has developed and has, for some years, commercially sold three-dimensional surface treatment equipment, operating under a capacitive electrode principle which creates a directional plasma within a tunnel or atmospheric chamber. The capacitive electrodes are placed on the opposite sides of the tunnel and a high voltage electric field is generated in such a way that a directional discharge of the plasma between the electrodes is effected. The Molded parts are put on a conveyor belt (or other means of transport) and transported through the treatment tunnel and are exposed to the plasma to treat the surface of the outer surfaces of the parts of the objects with little or no heat generated in the object. As the pieces fit within the treatment tunnel, the external surfaces of the parts will be treated substantially. In addition, Lectro Engineering Company of St. Louis, Missouri offers a commercial surface treatment equipment in which a gas or gaseous mixture (eg, air, CO2, argon, nitrous oxide, or a gas mixture) is introduced into the tunnel or in a closed chamber to facilitate the creation of plasma. It should be understood that when the term "gas" is used in this disclosure it may be a single gas, such as argon, but it may also be a mixture of two or more gases. The reference can be made to USPatents 4,317,778, 5,176,924, 5,215,637, US 5,290,489, 5,925,325 and 6,824,872 which disclose various plasma systems and methods.

BRIEF DESCRIPTION OF THE INVENTION Among the various advantages of the system and method disclosed herein can be seen the arrangement of a system and method for treating a corpuscular material, and particularly plastic resins, in such a way that the corpuscular material has increased the surface characteristics, even after the corpuscular resin is formed into an object. The treated corpuscular material (or the objects of or molded from said treated corpuscular material) may exhibit improved surface properties, such as the adhesion of inks, paint, or adhesives to the surface of the objects formed of the corpuscular material or changing the surface characteristics of the corpuscular material so that the corpuscular material can have better wettability in order to be able to mix the particles more easily with the paint or other liquid, or to improve the dispersion of the particles in a powder or a liquid. The provision of such a system and method that allows a corpuscular material, such as a plastic resin, to be treated continuously or in batches; The provision of such a system and method that, for most corpuscular plastic resin materials, does not damage, degrade or overheat the corpuscular material that is being treated; The provision of said system and the method in which the corpuscular material treated will retain its surface treatment for an adequate useful life to allow the treated particulate matter to be stored for a sufficient time to allow the molding of objects of the treated material in production environments commercial; and The provision of said system and method, which in certain modalities, does not require a vacuum chamber evacuated to a fixed vacuum; Other advantages and characteristics of this invention will be evident in part and in part point to ours from now on. In addition, those skilled in the art will recognize that the apparatus and methods described by the claims of this disclosure need not incorporate other advantages not described above. As briefly stipulated, one embodiment of the apparatus is presently described and is used to treat corpuscular materials (as described above) to change the surface characteristics (as described above) of the corpuscular material. As widely established, this apparatus comprises a working chamber (which may be a plasma tunnel open to the atmosphere or a closed container such that a reduced bag or a rigid wall container or a tunnel) that receives the particulate material to be treated. A power supply is provided to generate a plasma with which the corpuscular material is treated inside the working chamber. In addition, an amount of gas or gas mixture can optionally be introduced into the working chamber to facilitate the processing of corpuscular material. In another embodiment of the apparatus described herein, comprises a work chamber (as described above) that contains a quantity of corpuscular material that will be treated. A gas or gaseous mixture (as will be described hereinafter) can optionally be introduced into the working chamber to facilitate the generation of a plasma within the corpuscular material. A conveyor transports the corpuscular material through the working chamber to expose the corpuscular material to a plasma discharge and thus treat the corpuscular resin. Still further, another embodiment of the present apparatus treats corpuscular plastic resin to change the surface characteristics of the corpuscular resin and of the molded objects from the resin. These apparatuses comprise a plasma treatment tunnel in which a working chamber is provided to contain a quantity of corpuscular resin to be treated. A conveyor transports the working chamber through the tunnel to treat the corpuscular resin. Optionally, a partial vacuum can be extracted inside the working chamber, or the working chamber can be slightly pressurized above atmospheric atmospheric pressure. Also, a gas or a gaseous mixture (for example, air, CO2, argon, nitrous oxide, or a gas mixture) can be optionally introduced into the working chamber with or without the presence of a partial vacuum or with or without positive pressure for above the environmental inside the working chamber in a way that facilitates the generation of a plasma within the corpuscular material. Even further, the apparatus in accordance with certain aspects of this disclosure can be used to treat corpuscular plastic resin to change the surface characteristics of the molded objects from the resin.

Specifically, the apparatus comprises a working chamber (e.g., a tunnel) in which a plasma is generated. A quantity of corpuscular plastic resin is placed inside the tunnel. One or more doors can optionally close the atmosphere tunnel. A gas or gaseous mixture (such as those described above) can optionally be introduced into the tunnel where the corpuscular plastic resin is treated by the plasma to improve the surface characteristics of the corpuscular plastic resin and the molded objects from the resin treated. In addition, the partial vacuum or a positive pressure can optionally be extracted or formed inside the closed tunnel, preferably before the introduction of the gas or gas mixture. Alternatively, the apparatus according to certain aspects of this disclosure may comprise a plasma tunnel having a tube (a working chamber) extending therethrough. A conveyor (e.g., a screw conveyor) conveys a quantity of corpuscular material to be treated through the tube and exposes the corpuscular material to a capacitive directional plasma within the tube to treat the surface of the corpuscular material. A gas or gas mixture may optionally be introduced into the tube to facilitate the formation of a directional plasma discharge within the particulate material as the latter is transported through the tube. Still further, this disclosure discloses a method for treating corpuscular material (eg, corpuscular plastic resins) to improve surface characteristics of objects made from corpuscular material. This method comprises the steps of placing a quantity of corpuscular material to be treated in a working chamber, which can be a plasma treatment tunnel or a closed container. The working chamber is exposed to a plasma inside the tunnel to treat the corpuscular material inside the working chamber. The method may optionally include the steps of extracting a partial vacuum (or a positive pressure) within the working chamber, and introducing a gas or gas mixture into the working chamber to facilitate the generation of the plasma within the corpuscular material. Even further, this disclosure includes a method for forming plastic objects from corpuscular resin materials that have been treated, as described in one of the apparatus or methods described above, before molding the object from said treated corpuscular resins where The molded object has improved surface characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagrammatic view of the plasma tunnel (where in this mode it constitutes a working chamber) in which a quantity of corpuscular resin can be treated superficially, the tunnel has a pair of spaced capacitor elements energized through a transformer to generate a directional plasma discharge within the tunnel; Figure 2 is a diagrammatic view of the plasma tunnel similar to that illustrated in Figure 1, in which the capacitor is energized by a pair of transformers; Figure 3 is a diagrammatic view of a plasma tunnel in which the ends of the tunnel are closed by means of doors or the like and a gas or gas mixture is optionally introduced into the tunnel in such a way that a quantity of corpuscular material can be treated superficially within the tunnel, and where the tunnel can be optionally evacuated in a manner partial (or can be pressurized positively above the environmental) preferably before the introduction of gas or gas mixture; Fig. 4 is a diagrammatic view of a tunnel similar to that shown in Fig. 3 in which a closed working chamber is inside the tunnel where an optional mechanical stirrer (as shown in Fig. 7) is provided inside the chamber for stirring a quantity of corpuscular material to uniformly treat said corpuscular material, and in which a quantity of gas or gas mixture can be introduced; Fig. 5 is a diagrammatic view of a tunnel having a conveyor extending therethrough to convey a quantity of particulate material through the tunnel to be surface treated, where a manifold is provided within the tunnel to introduce a gas or a gaseous mixture; Figure 6 is a side elevational view of a closed, reduced working chamber or bag, adapted to retain a quantity of corpuscular material that will be treated and to optionally have a partial vacuum drawn thereto or have a positive pressure introduced therein. and a gaseous gas or mixture injected to facilitate the generation of the plasma discharged into the bag; Figure 7 is a side elevational view of the working chamber with rigid, closed wall, as it may be placed inside the plasma tunnel (as illustrated in Figure 4), containing a quantity of corpuscular material that will be treated by lustrating the provision of a mechanical paddle stirrer to mix the material corpuscular that is being treated to ensure a more uniform treatment of a corpuscular material, where a partial vacuum or a positive pressure can optionally be extracted inside the working chamber and where a gas or gas mixture can be introduced into the working chamber; Fig. 8 is a diagrammatic view of still another embodiment of the apparatus for treating the treated corpuscular resin having an elongated tube of a suitable dielectric material constituting a working chamber extending through a plasma treatment tunnel, this generating a plasma inside the tunnel and inside the ** tube, where the tube has a rotating auger disposed therein with the inlet end of the tube receiving a corpuscular resin supply and with an optional gas infusion module in communication with the tube to optionally instill a gas or gaseous mixture into the tube and into the corpuscular material within the tube, and where a rotating auger transports the corpuscular resin through the treatment tunnel to expose the particulate material to the plasma discharge as the corpuscular material is transported through the tube so that the treated corpuscular material is discharged from the tube; Figure 8A is a view of an alternate gas infusion module used in place of the gas infusion module shown in Figure 8; Figure 9 is a diagrammatic view of yet another embodiment of the apparatus for treating corpuscular resin material having a bulk supply of a corpuscular resin where the resin is optionally instilled with a gas or gas mixture and where the corpuscular resin / mixture The gas mixture is packed in sealed containers or work chambers, such as flexible wall bags, and where the bags of the resin / gas mixture are transported through a plasma treatment tunnel to treat the corpuscular resin inside the bags : Fig. 10 is a diagrammatic view of another embodiment of the apparatus disclosed herein wherein a batch of corpuscular resin to be treated is loaded into a vertical plasma treatment tunnel, where the tunnel can be closed after it is loaded with the resin corpuscular and where a gas or gaseous mixture can optionally be instilled into the corpuscular resin inside the closed tunnel either under ambient conditions, under a partial vacuum or under a sliy positive pressure in the environment so that the surface treatment of the corpuscular resin can be effected, where after the treatment, the treated resin can be discharged from the tube; and Figure 11 is still another embodiment of an apparatus described herein that treats corpuscular resin in a continuous flow process where the plastic resin particles are continuously discharged into a vertical plasma treatment tunnel and where a gas or gas mixture it is optionally instilled into the resin before or during treatment within the tube and where the treated resin is continuously discharged from the outlet end of the tube. The corresponding reference numbers are used through several figures of the drawings.

BEST WAYS TO CARRY OUT THE INVENTION The following detailed descriptions illustrate several preferred embodiments of the disclosures present by way of example and not by way of limitation. Additionally, it should be understood that the invention (s) described in the following claims are not limited in the request for the construction details and in the provisions of the components set forth in the following description of various embodiments disclosed herein in the Summary or in the Detailed Description of the Preferred Modalities, or illustrated in various views of the drawings. Referring now to the drawings, and more particularly to Figure 2, a first embodiment of the apparatus of this invention for treating the surface of a corpuscular material PM is indicated in full in point 1. The term "corpuscular matter", as used in this disclosure, includes, but is not limited to, powders, granulates or pellets of solid materials that are preferably, but not necessarily, fluid or pourable. Some examples of such corpuscular materials include plastic resins and inorganic materials such as paint pigments (e.g., titanium dioxide, TiO2), and elastomers or other plastic-like materials. Plastic resins that can be surface treated in accordance with this invention include, but are not limited to, polyethylenes, polypropylenes, ABS, PFTE, nylon, TPO, TPE, styrene, ABS, PVC, engineered plastics, acrylics, polycarbonates, a mixture of various resins, and / or regrinds of said resins. The term "surface treatment" said corpuscular materials include, but are not limited to, the improvement of said surface properties to increase in surface energy, frictional behavior, lubricity, the cohesive strength of the films, the electrical conductivity of the surface , the dielectric constant, the wettability characteristics (eg, both hydrophilic and hydrophobic), and the promotion of adhesion of inks, adhesives, and paints to the surface of said corpuscular materials and / or to the surface of the objects from said materials particular. The term "surface treatment" also encompasses the treatment of said corpuscular materials to alter the surface of said materials in order to increase the flow, mixture, dispersion, and / or gas or the particular migration of said materials.

One aspect of this disclosure is that the method and apparatuses described herein can be used to make said surface treatment of corpuscular material so that the objects formed (eg, molded) from the treated material have said improved surface characteristics. However, the treatment system and the method of treatment described herein may be used to treat the surface of other materials that are not used for molding or otherwise of the objects of the treated particulate materials. Referring now to Figure 2, a first embodiment of apparatus 1 of the present invention includes a plasma treatment tunnel 3, which constitutes a WC working chamber. At least a portion of the tunnel is disposed within a capacitor 5 having a pair of separate capacitor electrodes 7a, 7b. The electrodes are energized by a power source 9. The capacitor electrodes are energized by two high-voltage transformers 11a, 11b. As shown in Figure 1, a power source 9 'can also be a single high-voltage transformer 11c connected to the electrode 7a with the other electrode 7b connected to ground. When the power source 9 of the apparatus of any of Fig. 1 or Fig. 2 is energized, a directional discharge of PD plasma (as indicated by straight dotted lines between the electrodes) is generated inside the tunnel 3. As shown In several drawings, the dotted lines between the electrodes denoting the directional discharge of the plasma are omitted in various views of the drawings for purposes of clarity. Each of the capacitor electrodes 7a, 7b is contained in the housing 15. Said plasma discharge treatment tunnels are commercially available from Lectro Engineering Co., Inc., 1643 Lotsie Blvd., St. Louis, Mossouri 63132, www. . lectrotreat. com . While the capacitor electrodes 7a, 7b are shown in all figures of the drawings of this disclosure to be located above and below the tunnel of treatment arranged horizontally 3, it should be understood that the electrodes can be located on the opposite horizontal sides of the treatment tunnel. It should also be understood that when the term "plasma" is used in this disclosure, it is preferable to refer to a directional plasma. A first embodiment of the apparatus and the method of the present disclosure can be carried out in the apparatus as shown in Figures 1 and 2. There, the working chamber 3 is shown to be a tunnel disposed between the capacitor electrodes 7a, 7b and it is open to the atmosphere. As shown in Figure 2, a conveyor belt 19 has an upper reach 19a extending through the tunnel 3 for transporting particulate matter PM (or other objects) placed in this upper reach through the tunnel 3 to be surface treated by the PD plasma discharge formed in the tunnel. As shown in Figure 2, the upper reach 19a of the conveyor 19 may have a loose particulate material PM therein to be surface treated in accordance with this invention. Alternatively, an amount of corpuscular material PM can be placed in a closed container 21. As shown in Figure 4, the closed container 21 can be a rigid wall chamber or container 21a, or as shown in Figure 6, the Closed container 21 can be a reduced, flexible wall bag 21b transported through tunnel 3. An amount of gas or a gas mixture (as described hereinbefore) can (optionally) be introduced into the container (ie: in the container 21a or in the bag 21b) together with the corpuscular material PM to be treated before the container is transported through the tunnel and is exposed to the PM plasma discharge. This gas or gas mixture facilitates the generation of plasma within the corpuscular material. Still further, both the reduced bag 21b and / or the rigid wall container 21a can be partially evacuated (or slightly pressurized on ambient pressure). atmospheric) and the gas or gaseous mixture can be introduced into the closed container before being exposed to plasma discharge into the tunnel. It should be understood that both the introduction of the gas described above or gas mixture and the partial vacuum (or slightly positive pressure) inside the container or bag (or inside the tunnel) improves the processing of the corpuscular material and thus, in certain cases may be preferred, but neither gas, nor partial vacuum, nor slight pressurization are essential for the operation of the apparatus or essential for transporting the methods described herein. It should be understood that argon is the preferred gas, but that the use of argon or any other particular gas is not necessary, and that such treatment can be carried out with only the particular PM material exposed to atmospheric air at an ambient pressure. As used herein, those skilled in the art will understand that the term "gas or gas mixture" may include, bolt is not necessarily limited to, argon, carbon dioxide (CO2), a mixture of argon and air, nitrogen, air, nitrous oxide, or other gases). Also the terms "partially evacuated" or "partial vacuum" mean only that the pressure is reduced from the barometric atmospheric pressure to facilitate the introduction of the gas or gas mixture if said gas or gas mixture is used. It should be understood that the system and method of this invention will operate at atmospheric pressures or at a slight positive pressure compared to atmospheric atmospheric pressure, but the formation of a partial vacuum or a slight positive pressure around the particulate material PM to be treated may be preferential. As noted, after forming this partial vacuum within the container 21 (either the rigid container 21a or the bag 21b), the conductive gas can be introduced into said container so that the internal pressure of the container at the time of treatment can be in or near (example, something above or something below) the pressure atmospheric, but, of course, much of the air inside the container will have to be displaced by the conductive gas. Of course, after said container 21 has been transported through the tunnel, the corpuscular material can be emptied from the container for use as described above. As shown in Figure 5, a tunnel 3, as described above, is provided with a multiple M that is optionally supplied with a gas or gas mixture (as described above), which is dispensed into the tunnel as a supply PM corpuscular material is transported through the tunnel. It should be understood that argon is preferred since it facilitates the formation of the plasma within the particular material within the tunnel. However, other gases, such as those described above, can be used. Referring to Figure 7, the tunnel 3 constitutes a working chamber and an optional mechanical mixer 23 which is provided in the tunnel for mixing (stirring) the corpuscular material PM into the tunnel and for transporting the corpuscular material through the tunnel. so that the uniform treatment of the corpuscular material is substantially ensured. The mixer 23 is shown as a vane-type rotating mixer 25 having a horizontal axis 27 with radially extending vanes 29. The vanes 29 can be angled with respect to the axis 27 and are at least partly submerged in the corpuscular material PM so that both agitate and transport the corpuscular material through the tunnel as the shaft is rotated. The shaft 27 is rotationally driven via a variable speed drive motor 31 or a similar one so that the paddles move through the corpuscular material, the corpuscular material will be transported through the tunnel 3 and stirred and mixed to thereby ensure that most of the material is uniformly exposed to PD plasma discharge as the material is transported through tunnel 3. Other types can be used of mixers well known in the art. For example, instead of a mechanical pallet type mixer described above, the tunnel can be provided with a vibrating stirrer to agitate the tunnel whereby it causes the corpuscular material within the tunnel to be agitated inside the tunnel resulting in a uniform substantial mixing of the corpuscular material. Still further, the tunnel 3 may be provided with an infuser or an aerator which introduces a gas or gas mixture (as described above) into the corpuscular material. It has been found that an aerated stone, such as those used in a large aquarium, can be used to introduce the conductive gas into the corpuscular resin. As shown in Figure 8a, said aerator or infuser can be located on the central axis of the mixer / conveyor 27, which in Figure 8A is shown to be a screw conveyor. The gas can be withdrawn from the end of the exit tunnel by means of a compressor, and again introduced (recycled) into the container adjacent to the inner end of the tunnel to minimize the use of the gas or gas mixture. Even later, the lower part of the tunnel or container can be provided with a fluidization membrane (not shown) and a gas or gas mixture (described above) can be introduced into a space between the bottom of the container and the membrane of the container. fluidization so as to fluidify the corpuscular material and cause a rolling action in the corpuscular material which will result in a substantially uniform mixture of the corpuscular material.

Such fluidized membranes are well known to those skilled in the art, as shown in U.S. Patent 4,880,148, which is incorporated herein by reference. Referring to Figure 6, the container or container 21 is shown to be a flexible, reduced bag 21b. This bag can be made of a plastic film suitable (for example: polyethylene or a similar one) having a hole 33 which is closed by sealing after a quantity of particulate material PM is placed therein for surface treatment. As indicated by the arrows in figure 6, a partial vacuum or a slight positive pressure can be formed inside the bag 21 ba through a suitable vent in the bag opening with which at least some of the air is removed from the bag or slightly pressurize positively the bag and the gas or gas mixture (as described above) that can be injected into the bag through another vent. After the gas or gas mixture is introduced into the bag, the bag is sealed in such a way that it encloses the gas and particles within the bag. However, if, after the introduction of the gas, the pressure inside the bag is less than atmospheric, the atmospheric pressure on the outside of the bag will compress the bag into the corpuscular material of this and may increase the generation of discharge of plasma within the bag as the bag is transported through the plasma treatment tunnel 3. In Figure 8, a preferred embodiment of the apparatus for carrying out the method of this disclosure is shown in full in FIG. It should be understood that while the embodiment of Figure 8 is currently the most preferred modality, in certain occasions, another one of the various modalities described herein may be preferred, depending on several conditions. Specifically, the apparatus 101 provided for a continuous process of the corpuscular material PM and comprises a plasma treatment tunnel 103 similar to the tunnel 3 hitherto described with respect to figures 1 and 2. The apparatuses 101 have a WC working chamber within the tunnel 103 in the form of a screw conveyor 105 extending through the tunnel. The screw conveyor 105 includes a barrel tube 107, preferably of an insulating dielectric insulating material such as tempered glass, ceramic or the like. He The screw conveyor has a rotary driven auger 109 disposed within the barrel tube. The screw conveyor is rotationally driven by a variable speed reducer motor 111 and has a series of helical paths that have a sufficient closing fit within the bore tube to transport the corpuscular resin material from one end of the tube from the hole to another. The trajectory of the auger is shown to be secured to a central axis of bore 115. However, it should be understood that other types of conveyors, such as the chain conveyor and the "ascentric" screw conveyors can be used. Preferably, the speed of rotation of the motor 111 can be varied to vary the speed of rotation of the borehole and thus increase or decrease the amount of corpuscular resin transported through the screw conveyor in a unit of time, and / or to vary the time in which the corpuscular queen remains in the tunnel to carry out the treatment. As described, the screw conveyor 105 constitutes a working chamber in which the corpuscular material PM is treated by the plasma generated by the capacitor electrodes 7a, 7b. As indicated at 117, the screw conveyor 105 has an inlet end, which is in communication with a supply of particulate material PM to be treated. More specifically, a corpuscular resin hopper 119 is provided, it has a supply of corpuscular queen material 121 therein. As will be understood by those skilled in the art, the corpuscular resin can be supplied to the hopper 119 in any of the numbers in different manners, none of which is critical to the operation of the apparatus 101. For example, a pneumatic corpuscular system, as will be described hereinafter with respect to Figure 9, it can be used, or the resin can be manually emptied into the hopper from the bags or the like. The corpuscular resin is fluid and will enter the input end 117 of the screw conveyor 105 so that the rotary paths of the auger 113 are transported to the corpuscular material through the length of the screw conveyor and therefore through the plasma tunnel with the apparatus 101 to be exposed to the plasma generated with the apparatus to treat the corpuscular material. A gas transport infuser module, as generally indicated at 123 about a portion of the barge tube 107. The infusion module is supplied with the conductive gas (as described above) under pressure from the supply 125 of said conductive gas Alternatively, the gas can be instilled into the corpuscular material using an aerator or an infusion stone, as described above. Typically, the flow rate of the gas or gas mixture (preferably argon / air mixture) is regulated at a desired flow rate of operation of about 0 to 100 standard cubic feet / hour (CFH) or more, depending on the application and the amount of particulate material to be treated in a given period of time. Generally, the gas flow rate is regulated so that a uniform plasma is generated with the tube 107 and within the corpuscular material between the trajectories 113 of the bore 109. As described so far, the use of said gas or gas mixture may be preferred, is not necessary in the practice of the system and method of this disclosure. As described so far, gases such as air, CO2, argon, nitrous oxide, or a mixture of such gases can be used, but (as indicated above), the preferred one is argon. As shown in Figure 8, the infusion module 123 has a ring 129 that surrounds a portion of the bore tube 107 with the ends of the ring being sealed with respect to the exterior of the tube. One or more holes 131 are provided through the barrel tube 107 within the region of the ring 129 so that the conductive gas can be instilled through the barrel tube and into the corpuscular material which is going to be transported through the borehole tube. It should be aciated that the path 113 has a sufficient closing fit within the internal diameter of the barrel tube 107 to thereby effectively prevent excess leakage of the conductive gas from the ends of the screw conveyor 105 as the corpuscular material It is transported through the screw conveyor. As indicated at 133, the outlet end of the screw conveyor 105 extends beyond the end of the barge tube 107 and is in communication with the discharge hopper 135 disposed below the outer end of the borehole to discharge the corpuscular material. treated and to direct it down to be received in a suitable container or bag (not shown) for shipping or storage. It will also be understood that in a continuous process, the treated material can be transported directly from the outer end 133 of the screw conveyor to a storage tank or to the entrance of a molding machine so that the objects can be molded from the corpuscular resin treated. In Figure 8A, another and more preferred embodiment of the infusion module is indicated in its entirety at 123 '. In this embodiment, the gas supply 125 is connected to the tube 137 at the inlet end of the shaft of the bore 115 where the tube 137 extends axially inward a short distance beyond the particular hopper 119. This tube is in communication with one or more acceleration holes 139 arranged in the central axis to extend outwardly through the portions of the screw conveyor between the paths 113. These aeration outlets 139 are porous to discharge the gas towards the particulate material PM between the paths basin. Since the blasthole paths 113 have a relative closure fit within the barrel tube 107 (not shown in Figure 8A) and since the gas is instilled at a relatively low differential pressure with respect to atmospheric pressure, the gas will be effectively enclosed between the spaced path 113 of the screw conveyor. Also, as the auger is rotated and as the gas is continuously discharged from the aeration outlets 139 to the corpuscular material, a good gaseous mixture of corpuscular material is achieved, which facilitates the generation of a uniform plasma within the barrero tube and within the particulate material PM as the corpuscular material is transported from the inlet end to the outlet end of the barrero tube. In Figure 9, another embodiment is shown, as indicated in full in 201, of the improved treatment apparatus is disclosed where the work containers or work chambers, which can be reduced bags as previously described with respect to to figure 6, or they can be containers or containers of rigid wall, to treat the corpuscular resin. These apparatuses 201 comprise a plasma treatment tunnel 203 similar to the tunnel 103 described above having spaced capacitor electrodes 7a, 7b on opposite sides of the tunnel, which are energized by one or more adequate energy supplies, as described above. The apparatuses 201 have an endless conveyor 205 having an upper section extending through the tunnel 203. When the working chambers 207 (whether reduced bags or rigid wall containers) of the resin to be treated are placed in the upper section of the conveyor 205, the work chambers 207 are transported through the tunnel and are exposed to the plasma generated by the electrodes in the manner described so far. It will be carried out by those skilled in the art that other conveyors may be used instead of the conveyor belt described above. For example, a rotating conveyor could be used to transport work chambers through the tunnel. Apparatus 201 includes a corpuscular resin supply, as indicated at 209, contained within a supply container 211. A resin transporter vacuum system, as generally indicated at 213, includes a suction tube 215 that is in communication with the resin supply 209 within the container 211 The resin of the container 211 is a vacuum transported and deposited in a hopper loader 217, which feeds the resin down through an outlet. A gas infuser 219 is optionally provided to mix an amount of a gas or gaseous mixture (as described heretofore) with the corpuscular resin as it is discharged from the hopper loader. Again, argon is the preferred gas, but it will be recognized that other gases or gas mixtures can be used, or no gas can be used. As shown, the infuser 219 mixes a gas supply from the conductive gas supply 221 with the particulate material feed from the hopper loader 217. A flow regulator 223 is used to ensure that a desired amount of the gas is mixed with the corpuscular material as the latter is discharged from the hopper loader 217 towards the chambers (bags) 207. Prior to the introduction of the gas into the chambers 207, it will be appreciated that a partial vacuum can be drained into the chamber for so move the air from the inside of the camera. A slide gate valve 225 can be operated to start or stop the flow of particulate material from the hopper 217 to the bags 207. As shown in FIG. 9, the corpuscular material and the instilled gas (if said gas is used. ) are arranged in a bag 207 and the bag is sealed. The sealed work chambers contain the corpuscular material and the gas can be stored for some time and sent to a remote location to be treated in tunnel 203 or the bags can be directly taken to the treatment tunnel for treatment. It has been found that sealed work chambers or Bags can be stored for an appreciable period of time before being treated. This allows the bags filled with corpuscular material and gas (if used) to be sent to the location of the treatment tunnel and where they can be treated. In addition it has also been found that if the treated corpuscular resin remains in the sealed bags or in the working chambers after treatment, the treated corpuscular resin will maintain its treatment for up to 180 days or more after treatment. When it is desired to treat the corpuscular material in bags (work chambers) 207 the bags are loaded in the upper section of the conveyor 205 and transported through the directional plasma treatment tunnel 203 in order to be exposed to the plasma discharge inside the tunnel and thus treat the surface of the corpuscular material within the chambers or pouches 207. The speed at which the conveyor is operated and the length of the treatment tunnel along with the force of the plasma within the tunnel will determine the degree to which the corpuscular material Inside the bags is treated. Of course, the speed of the conveyor 205 can be selectively varied within a limited range. Referring now to Figure 10, a group treatment system for treating corpuscular material is indicated in its entirety at 301. This system uses a vertically arranged treatment tunnel 303 or WC work chamber, which constitutes a gravity conveyor for transporting the corpuscular material through the working chamber, which has electrodes 7a, 7b (not shown in Figure 10) on opposite sides of the tunnel where the electrodes are energized by a suitable power source, as described so far. The tunnel 303 has an opening of the opening 304 and a door 305 at its lower or outlet end and thus the tunnel constitutes a working chamber within which the particulate material PM can be treated to improve its surface characteristics. With the door 305 closed, the tunnel 303 is filled with a corpuscular material to be treated and an upper or entry end door 309 is closed. As shown, tunnel 303 can optionally be connected to a vacuum source 311 so that with doors 305 and 309 closed, a partial vacuum can be drained with tunnel 303. A gas or gas mixture can optionally be introduced. to the tunnel after the partial vacuum reported above is drained using a gas infuser or an aerator 313 can be used to instill the particulate material with a gas charge or a gas mixture to facilitate the generation of the plasma within the corpuscular material within of the tunnel. That is, the aerator 313 is removed within the tunnel which is connected to a supply 315 of the gas to be instilled and a predetermined volume of gas can be introduced into the closed tunnel, preferably after said partial vacuum has been extracted into the tunnel . Before treatment, the pressure inside the tunnel or the working chamber may be slightly low, at or above atmospheric pressure. After a corpuscular resin material 307 inside the tunnel 303 has been exposed to the plasma for a sufficient time as a successful treatment, the lower door 305 is opened and the treated particulate material will be discharged by gravity from the tunnel 303 through opening 304 towards the suitable container or hopper (not shown). The length of time in which the material 307 is exposed to plasma discharge depends on a number of factors, such as the material to be treated, the dimensions of the tunnel, if a gas or a gas mixture is used, and the strength of the plasma directional used to treat the material. Referring now to Figure 11, another embodiment of the apparatus of this disclosure is illustrated in its entirety at 401. This mode continuously treats the corpuscular resin material 403. Again, in this embodiment a tunnel of Treatment 405 is oriented so that the tunnel is arranged in a vertical position with the capacitor electrodes 7a. 7ben the opposite sides of the tunnel. The tunnel 405 has an upper or inlet end 407 and a lower or outlet end 409, and thus forms a working chamber within the tunnel 405 within which the corpuscular resin material can be treated. As indicated at 411, a gate is provided at the exit end 409 to thereby regulate the flow of the particulate material 403 through the tunnel 405. Thus, the gate 411 acts as a valve to regulate the flow of the particulate material through of tunnel 405 and the tunnel serves as a gravity conveyor to transport the particulate material through the tunnel or WC work chamber. A hopper loader 403 is supplied with a corpuscular plastic resin to be treated from a supply (not shown in Figure 11) by means of a vacuum conveyor 415 similar to the vacuum transport system heretofore described with respect to the Figure 9. It will be understood that a gravity feed may be used in place of vacuum conveyor 415. In addition, a gas infuser 417 (similar to infuser 219 shown in Figure 9) is supplied with a suitable gas from the supply of gas or gas mixture 419 so that the suitable gas (as described heretofore) can optionally be instilled with the particulate material as the latter is shipped towards the upper end of the tunnel 405. During use, the system shown in the figure 11 dispenses a stable flow of the corpuscular resin to be treated from hopper 413. As the corpuscular resin passes through infuser 417, it can be instilled with a conductive gas. The resin and the conductive gas fall down through an opening in the closed end of the inlet 407 of the tunnel 405. As shown by the spaced points in the tunnel 405, the index where the treated corpuscular resin is discharged starting from the output end 409 is regulated by gate 411 so that a The corpuscular resin supply can be accumulated inside the tunnel 405. The resin is exposed to the plasma discharge from the capacitor electrodes for a sufficient time to treat the corpuscular resin. The treated corpuscular material is continuously discharged into a suitable container. Example 1 - A sample of a high density polyethylene powder (HDPE) was loaded into a reduced plastic bag and a gas mixture argon and air was introduced into the bag and then the bag was sealed. The bag with the resin inside was transported through the plasma treatment tunnel at a transport rate of approximately 2 feet / minutes and exposed to a directional plasma discharge for approximately 2 minutes. The surface level (also refers to the surface energy) of the resin before the treatment as determined by approximately 36 dynes. Note, that while a "dina" is generally understood as a unit of force that acts as a mass of one gram, increase its speed by one centimeter per second every second along the direction in which it acts in mass of a gram, increases its speed by one centimeter pro second every second along with the direction it acts, the term "dyne" as used in the present is an arbitrary unit of measurement to compare the surface energy of the corpuscular material and only represents a Relative comparison of the change in the surface energy of the corpuscular material after experiencing the treatment. After the treatment, the surface energy of the example has been increased to approximately 48-50 dynes. Several days after the treatment, an object was molded from the corpuscular resin treated in a rotational molding process where the molded object has an empty inner hole where a foam insulating material was applied. It was found that an excellent foam insulating adhesive was achieved. It is noted that higher surface energy levels typically indicate better adhesion of paints, inks, adhesive and similar. The surface tension (energy) of the level of these examples was determined using a test kit commercially available from Lecto Engineering Company of St. Louis, Missouri. The surface tension level of an example of a corpuscular material was tested by compressing an example of a corpuscular material to a known density and then applying it to a different surface or wettability tension solutions to the upper surface of the example to determine which solution could be used. moisten the particles and be absorbed in the example, where each of the solutions has a predetermined level of dyna. Example 2 - At approximately one month intervals, the corpuscular resin samples treated in accordance with Example 1, above, the surface energy of the samples were tested on a monthly basis for approximately 6 months. As reported, the surface energy of the corpuscular resin has been increased from about 36 dynes to about 48-50 dynes immediately after the treatment. During the course of this six-month trial period, surface energy remained at a level of 48-50 dynes. As several changes could be made to the above constructions without departing from the approach of the invention, it is intended that all matters contained in the above description or shown in the accompanying drawings should be construed as illustrative and not in a limiting sense.

Claims (12)

1. Apparatus for treating treated corpuscular material to change the surface characteristics of said corpuscular material, said apparatus characterized in that it comprises: a working chamber receiving the corpuscular material that will be treated; a power source; and a pair of separate capacitor electrodes energized by said power supply, said electrodes generating a plasma to treat the corpuscular material within said working chamber when placed between the electrodes.

The apparatus according to claim 1, further characterized in that the working chamber is a closed container and has said corpuscular material and a gas therein, said gas facilitating the generation of the plasma within the corpuscular material with said gas being selected to from the group comprising: air, nitrogen, argon, carbon dioxide, nitrous oxide, or a mixture of said gases.

The apparatus according to claim 1, further characterized in that the working chamber is a tunnel with the electrodes arranged with respect to the tunnel to generate a plasma within the tunnel, the apparatus further comprises a conveyor extending through said tunnel. tunnel to transport the corpuscular material through it.

The apparatus according to claim 3, further characterized in that the working chamber is a tube, and wherein the conveyor is a screw conveyor disposed within the tube.

The apparatus according to claim 3, further characterized in that a gas is introduced into the tunnel to aid in the treatment of the material corpuscular by means of said plasma.

The apparatus according to claim 4, further characterized in that the screw conveyor is a rotary screw conveyor and has at least one helical path in such a way that said screw conveyor is rotated, the auger transports said corpuscular material to through said tube.

The apparatus according to claim 4, further characterized in that the tube is of a suitable dielectric material.

The apparatus according to claim 4, further characterized in that the tube has a gas infuser to introduce the gas into the corpuscular material.

9. The apparatus for treating corpuscular plastic resin to change the surface characteristics of the molded objects from said resin, said apparatus characterized in that it comprises: a capacitor having a pair of electrodes spaced to generate a plasma; an amount of said corpuscular resin to be treated; and a conveyor for transporting said corpuscular resin between said electrodes to treat the corpuscular resin.

10. A method for treating a corpuscular material to improve the surface characteristics of the objects made from said particular material, characterized the method because it comprises the following steps: placing a quantity of corpuscular material that will be treated in a working chamber; and exposing the working chamber to a plasma to superficially treat the corpuscular material.

11. The method according to claim 10, further characterized in that the plasma is generated by means of a pair of spaced capacitor electrodes.

12. A method for treating corpuscular plastic resin to improve the surface characteristics of the molded objects from said resin, the method comprising the following steps: superficially treating the corpuscular plastic resin before molding the objects from said treated corpuscular plastic resin; characterized in that the treatment step includes: exposing the corpuscular plastic resin to a plasma to treat the surfaces of the plastic resin particles; and molding an object of said treated corpuscular resin material to improve the surface characteristics of said object.