WO2009106905A1

WO2009106905A1 - Apparatus for processing miscellaneous plastic wastes to obtain matrix material or composite material

Info

Publication number: WO2009106905A1
Application number: PCT/HU2008/000023
Authority: WO
Inventors: Mihály SZILVÁSSY; Miklós NÉMETH
Original assignee: Szilvassy Mihaly; Nemeth Miklos
Priority date: 2008-02-27
Filing date: 2008-02-27
Publication date: 2009-09-03

Abstract

The invention relates to an apparatus for processing miscellaneous plastic wastes to obtain matrix material or composite material. A recovering machine (1) has a heat transmission block (14) consisting of the inside surface (131) of the heat chamber (13) and the elements (141) situated between the inside surfaces (131) provided with prickling tips or cutting edges suitable for breaking through the inputted plastic wastes, the mixing drum (23) of the homogenizing machine (2) has at least two rotors (233) co-moving with the two parallel axles (2331), having blades (2332) and a bearing holding sheet (2333), on the outer surface of the rotor (233), there is a displacing device (234), comprising a driving rod (2341), a displacing rod (2342) and a pressure plate (2343) facilitating displacement of the homogenised material, and the homogenizing machine (2) has a moving device (25) to control moving the displacing device (234) in and out.

Description

Apparatus for processing miscellaneous plastic wastes to obtain matrix material or composite material

The object of the invention is an apparatus for processing miscellaneous plastic wastes to obtain matrix material or composite material, which is suitable for significantly reducing the volume of the contaminated miscellaneous plastic wastes to a level of 0.5 kg/dm³ HBD (high bulk density), and for rearrangement of the molecular structure of the recovered material of melted state and the one or more filling materials added in a way that the some of the old chemical links are broken while new molecular links are established between the different materials. In what follows, the term "matrix material" will denote the pure material (containing no additive) obtained as a final product of the processing, while the term "composite material" will denote the product obtained by adding the required quality and quantity of filling material(s) to the matrix material.

The problem of recycling plastic wastes, especially contaminated miscellaneous plastic wastes, has not been solved to date. Production and usage of plastics is continuously increasing, resulting in an increasing amount of plastic wastes as well.

Plastic wastes can be classified in three groups:

I. Technological wastes, manufacturing wastes, processing wastes. They usually do not get into the environment. Directly or after chopping or crushing, they can be recycled into the manufacturing process.

II. Industrial wastes, further processing wastes, confectioning wastes. Usually they are produced in the course of processing and confectioning the plastic semifinished products at the place of application. They are of the homogeneous type, clean, their utilization is usually solved: they are either repurchased by the manufacturers of the semifinished products, or purchased by companies specialised in waste recycling. [II. Wastes of plastic products after they have been used, packaging materials, hollow articles, used products. This latter category of plastic wastes causes the most significant problem. Recycling of plastic wastes placed at rubbish-shoots is an issue of key importance all over the world. The properties of plastics that are advantageous when they are used - e.g. they do not decompose due to external environmental effects, do not become rotten, they are of low density and high specific volume - become disadvantage when they get to the rubbish- shoot. Despite of the fact that about 10 % of household rubbish is plastic, and that 1.5 % of the total rubbish placed at rubbish-shoots containing building rubbish as well is plastic, it seems to be much more, as it has high volume as compared to its mass.

Due to their special physical and chemical properties, reusing and especially recycling of plastics require novel approach. In the frame of selective waste collection, plastics of public use of different polymer matrix are collected in one group as "plastics", irrespective of what these plastics are actually made of. A further problem of recycling is that there may be hundreds of variants or, in case of certain mass-produced plastics, even thousands of variants within a single type of plastic. Utilization of miscellaneous plastic wastes is a critical issue in our days. It is usually considered in our days that technical depreciation inevitably takes place in the course of recycling, and as a result, the recycled plastic can only be applied for purposes of lower standard.

Contaminated and miscellaneous plastic wastes - according to the present state of art - can not usually be economically recycled, their utilization requires new methods. The more contaminated and miscellaneous the plastic waste to be prepared for recycling is, the more expensive the preparation is. It is especially true for the plastic content of highly miscellaneous, highly contaminated household wastes originating from consumer's packaging, even if it is coming from selective waste collection.

From another aspect, the serious problem of management and/or disposal of communal wastes is even made more difficult by plastic wastes, as due to their shape (mainly foils, foams, bags, bottles) and low specific weight they can be carried by the wind, they do not or hardly decay in a biological way, and they increase the cubic content of rubbish. Disposal of these plastic wastes and especially the compression thereof is of primary interest in itself, however, it is especially advantageous if they can be used for producing useful products that can substitute for other materials of technological use that can only be obtained from the nature — especially wood.

Composite materials comprising thermoplastics and filling materials have been prepared and used for decades, however, in the traditional processing equipments it is a requirement that the plastics to be processed must be clean. Therefore with these methods one can process either new thermoplastics or plastics obtained from accurate selective waste collection after thorough separation and cleaning. In Hungary it is only about 15 % of the plastic wastes that can be collected for reprocessing via selective waste collection and industrial recycling in our days. And even of this 15 % only the cleanest, most valuable part is recycled, the remainder is placed embaled at the rubbish-shoots, increasing the pollution of the environment. In lack of appropriate processing technology, in spite of the well- founded social demand, primarily due to lack of money, there is not much hope for the processing of the remaining 85 % and the utilisation of its plastic content.

In the course of the traditional methods, the first step of processing the plastic wastes to be utilized is selecting and chopping. Besides the significant energy consumption of chopping there are technical difficulties as well. Foils may slip near the knives, and even the smallest metal pieces may cause the blades to break or damage the entire machine, while fibrous plastics (cords) may roll onto the shafts of rotating parts. Therefore it is the process of chopping that should be avoided as a first step of processing contaminated heterogeneous plastics.

As the second step of traditional methods the chopped waste "crushing" (which, as we have mentioned, can primarily be gained from expensive and accurately selected, relatively clean base material, with difficulties and high energy consumption) is homogenized while it is heated in a mixing process, in certain cases with filling materials added, than this material is injection moulded or extruded to obtain its final form in a shaping tool. This known method has the disadvantage that the matrix material thus obtained or the composite material obtained with the filling materials added easily breaks into its components upon mechanical stress, so its applicability is quite limited. In the course of these methods certain plastic wastes are in fact compressed, however, the other object, the production of useful material substituting for natural material is not satisfactorily solved.

Among patent documents, the prior art is represented e.g. by patent specifications EP 0531957, JP 2001137735, JP 2001145949 and HU 209087 as well as the process presented in specification HU 204461, which relates to regeneration of thermoplastic wastes with additives and organic metal compounds mixed to it at specified temperature and shear applied, than, in the course of further heat processing the mixture is homogenised and granulated in a known way. At this known method the plastic wastes are regenerated in a chemical process making use of certain additives.

Also the prior art is represented by the invention presented in patent specification HU 218834, the object of which is method and apparatus for processing a mixture of materials containing several types of plastics, especially for recycling of mixed plastic from communal wastes. The process, in the first step of which the material to be recycled is, chopped than the magnetic portion of the chopped material is separated, has the fundamental idea that the chopped material is compressed by applying heat and/or pressure while the easily transportable or volatile components are removed by a suction machine, the compressed or compacted material is dried and finally classified in to fractions. This known method requires a chopping machine, a magnetic separator, a compressing unit, a suction machine, a drying unit and a filter unit, which increases production costs significantly.

Also the prior art is represented by the apparatus presented in patent specification WO 96/22867 suitable for heat treatment of bulk material of plastic content and selective softening of the plastics in the flow of the mixture to be used for recycling purposes. According to this invention, the bulk material is carried to the place of heat treatment by a pulley-driven belt-conveyor, while the heat energy is supplied by a heat radiator (infrared radiator or high-frequency radiator). At this known solution the bulk material is also softened by heat treatment, however, the technical solution is completely different from the apparatus according to our invention.

Also the prior art is represented by the apparatus for melting resin wastes and reducing the volume thereof and method for volume reduction presented in patent specification EP1422035. The apparatus comprises a feed opening, a cutting machine, a pulley-driven belt-conveyor, a smelter and an outlet opening. In the course of the processing, the resin waste is crushed, the crushed waste is sorted according to size, and the screened material is heat treated during transportation by the belt-conveyor. The aim of this solution is also to compress and melt the waste, however, this goal is achieved by crushing the waste and sorting the crushed waste, and the sorted crushings are compressed and melted during transportation by the pulley-driven belt-conveyor.

Also the prior art is represented by the technical method presented in patent specification EP 1510321 relating to manufacturing of recycled products by casting melted plastic waste. This known method includes cast moulding of the melted plastic waste, in the first step of which two or more types of plastic wastes (which may contain contaminated, printed and coloured material as well) are fed into a smelter where the different types of materials are melted together, and in a subsequent step the melted material flows into a pre-heated mould due to its own weight. Afterwards, the mould is intensely cooled with cold water, than the cooled mould is opened. This known method is suitable for processing all kinds of contaminated plastic that can be melted and cast due to its own weight. Among others, the method and the apparatus of the method comprises a channel-like pre-heating chamber that is surrounded by a hollow coating (similarly to a vacuum flash) in which hot air can flow, and a melting chamber which is heated by hot air of 300-400°C from the bottom providing a temperature of 200°C for melting. The melted material gets into an electrically heated tank where it can be stored hot until usage, from where it can be let into the above mentioned mould due to its own weight when using it. This known method is primarily suitable for processing miscellaneous wastes that are relatively clean from the mechanical point of view, it is not suitable for the processing of rough plastic wastes mixed with miscellaneous rubbish. The technological process moving along on steel rails is precisely elaborated from the mechanical and heat economy point of view, however, in contrast with our invention, it makes use of several special purpose machines, therefore it is relatively complicated and expensive to manufacture.

The object of the invention is to eliminate the deficiencies of the known solutions and to create an apparatus for processing miscellaneous plastic wastes to obtain matrix material or composite material, which apparatus is suitable for producing

- valuable, chemically stable matrix material suitable for further processing, possessing favourable physical properties (pressure-tight, of high tensile strength, UV resistant and resisting to weather), or,

- by adding one or more filling materials, producing technologically valuable composite material suitable for substituting building materials and wood,

- from useless miscellaneous plastic wastes,

- without cutting, carving, crushing, pellet-, crush- or other kind of homogenising, pre- cleaning, washing, drying or applying other material treatments usually applied in the known plastic recycling machines,

- by radically reducing the volume of the plastic waste, in relatively few technological steps, effectively, economically, and with less energy consumption.

The fundamental idea of the invention is that if we construct an apparatus that has a recovering machine which removes the miscellaneous plastic wastes not by extruding but partly by heat-treating through its increased heat transmission surface and partly by pressing under a movable press exposed to a certain pressure, and further, it has a homogenizing machine for further processing the melted, recovered material and the one or more filling materials added, and with its compound, heated mixing drum provided with rotors, the homogenising machine can heat and mix the melted, recovered material and the filling materials added and expose it to shearing and compressive stress in a way that the melted material is rearranged at the molecular level, that is, some old molecular links are broken, while new molecular links are established between the different materials, this way the melted, recovered material is homogenised either in itself, or with the filling material added, and further, the melted material is removed through the outlet opening by the displacing device of the mixing drum, the objectives are attained by are apparatus according to the invention.

The problem is solved by the invention as set forth in claim 1. The features of the certain embodiments are presented in the sub-claims.

The apparatus according to the invention is presented in more detail based on the attached drawings, in which:

Figure 1 is a sketch of the recovering machine according to the invention in longitudinal section, with the press in its lower position, Figure 2a is a sketch of the homogenizing machine according to the invention in front view, with the shutting piston in its upper position, Figure 2b is section D-D of the homogenizing machine of figure 2a, with the shutting piston in its upper position and the outlet opening in its closed position, Figure 3 is a sketch of the recovering machine according to the invention in longitudinal section, with the press in its upper position, Figure.4 is section D-D of the homogenizing machine of figure 2a, with the shutting piston in its lower position and the outlet opening in its open position, Figure 5a is a front view of the displacing device according to the invention in the state of mixing, partly in elevation, partly in section, Figure 5b is section B-B of the displacing device according to figure 5a in the state of mixing, Figure 6a is a front view of the displacing device according to the invention in the state of pressing out the homogenised material, Figure 6b is section C-C of the displacing device according to figure 6a in the state of pressing out the homogenised material. W

Figure 1 shows a sketch of the recovering machine 1 according to the invention in longitudinal section, with the press 11 in its lower position. The recovering machine 1 comprises a press 11 having a press plate 111 and a press hydraulic system 112, a feed opening 12 between the press plate 111 and the upper part of the preferably double-walled heat chamber 13 having an inside surface 131 and an outside surface 132, which feed opening 12 is suitable for feeding preferably pre-selected plastic wastes in the lower, basic position of the press 11, further, the recovering machine 1 comprises a heating pipe system 15 surrounding the heat chamber 13, provided with an inlet stub 151 and an outlet stub 152 suitable for letting in and out the heating agent, a heating agent tank 16 situated inside the heat chamber 13, and a discharge opening 17 for letting out the melted recovered material. The recovering machine 1 has an increased heat transmission surface designed as a heat transmission block 14 consisting of the inside surface 131 of the heat chamber 13 and the elements 141 situated between the inside surfaces 131, provided with prickling tips or cutting edges, suitable for breaking through the inputted plastic wastes.

Figure 2a is a sketch of the homogenizing machine 2 according to the invention in front view, with the shutting piston 21 in its upper position. The homogenizing machine 2 has a shutting piston 21 moved by a driving gear. The figure also shows the power transmission shaft ends 24 to which a motor can be connected, the outlet opening 231, the first heating connection 2321 and the second heating connection 2322, the mixing drum 23, the bearing holding sheet 2333, the displacing device 234 with the driving rod 2341 and the pressure plate 2343, and the moving device 25 with the working cylinder 251 and the shaft 252, suitable for moving the displacing device 234 in and out.

Figure 2b is section D-D of the homogenizing machine 2 of figure 2a, with the shutting piston 21 in its upper position and the outlet opening 231 in its closed position. In its upper position, the shutting piston 21 acts as a feed inlet 22 for feeding the recovered material, while in its lower position, the shutting piston 21 acts as a closure of the mixing drum 23 which is opened at its top, providing a hermetic sealing thereof. On its bottom part, the mixing drum 23 has an outlet opening 231 possessing an opening- closing element 2311₃ further, the mixing drum 23 the has a heating system 232 comprising a first heating connection 2321, a second heating connection 2322, heating pipes 2323 and a heating cover 2324. As shown in the figure, the mixing drum 23 has preferably four rotors 233 co-moving with the four parallel axles 2331 onto which they are mounted, having blades 2332. On the outer surface of each rotor 233 there is a displacing device 234 co-moving with the rotor 233, comprising a driving rod 2341 and a displacing rod 2342, facilitating displacement of the homogenised material.

The angle between the blades 2332 of the two adjacent upper rotors 233 and the two adjacent lower rotors 233, as well as the angle between the blades 2332 of the upper rotors 233 and the respective lower rotors 233 below them is preferably 90°.

Figure 3 is a sketch of the recovering machine 1 according to the invention in longitudinal section, with the press 11 in its upper position. In this position - which is preferably controlled by an end-position switch - there is a safety gap 18 between the press plate 111 and the breaking-through ends of the elements 141 of the heat transmission block 14, so as to prevent the press plate 111 from damaging the prickling tips or cutting edges of the elements 141 of the heat transmission block 14. The controlling makes the press hydraulic system 112 to move the press 11 into this upper position, and obviously in this position the feed opening 12 suitable for feeding the plastic wastes is out of operation, as it is prevented by the safety gap 18 of 0,05 - 0,5 mm, preferably 0,1 mm size.

Figure 4 is section D-D of the homogenizing machine 2 of figure 2a, with the shutting piston 21 in its lower position and the outlet opening 231 in its open position.

It can be seen in the figure that the mixing drum 23 is hermetically closed by the shutting piston 21, and the opening-closing element 2311 is removed from the outlet opening 231 so that the mixed, homogenized material can be pushed out after mixing.

The other parts of the homogenizing machine 2 have been described in connection with figure 2b. Figure 5a is a front view of the displacing device 234 according to the invention in the state of mixing, partly in elevation, partly in section, where the displacing device 234 is preferably a slotted cylinder. The figure shows the shaft end 24, the rotor 233, the axle 2331 and the blade 2332, when the displacing device 234 is outside the blade 2332 of the rotor 233.

Figure 5b is section B-B of the displacing device 234 according to figure 5a in the state of mixing. This figure clearly shows the axle 2331 and the displacing device 234, which facilitates continuous mixing in this case.

Figure 6a is a front view of the displacing device 234 according to the invention in the state of pressing out the homogenised material. In this case the displacing device 234, which is also a slotted cylinder co-moving with the rotor 233, slides onto the blade 2332 of the rotor 233 and closes it, as it is shown in figure 6b presenting the section C-C of the displacing device 234 according to figure 6a, together with the axle 2331.

The operation of the apparatus according to the invention is now described based on the drawings.

The pre-selected plastic wastes get to the recovering machine 1, preferably on a belt- conveyor, and from there, e.g. by manual feeding, they get into the heat chamber 13 through the feed opening 12 in the basic (shut down) lower position of the press 11. As the plastic wastes are fed, the press 11 automatically presses the thermoplastic wastes to the elements 141 of the hot heat transmission block 14 and the inside surface 131 of the heat chamber 13 acting as an increased heat transmission surface, and the plastic wastes are melted there. By moving the press 11 upwards, further pieces of the plastic waste get into the heat chamber 13, and due to the pressure effected by the press 11, the material to be recovered gets through the prickling tips and cutting edges of the elements 141 of the heat transmission block 14, and in a compressed state it moves towards the bottom of the heat chamber 13. When the material slips down to the lower end of the elements 141 and gets to the bottom of the heat chamber 13 it is melted, and, as a result of the further pressure, after the discharge opening 17 has been opened, the recovered material is pressed out through the discharge opening 17 and it is ready to enter into a following technological step. The temperature of the recovered material melted by the pressure and the heat is between 130°C and 29O⁰C, preferably it is 240⁰C.

The heat transmission surface of the recovering machine 1 is the inside surface 131 of the heat chamber 13 and the elements 141 of the heat transmission block 14. The heat chamber 13 is preferably a double-walled vessel which is heated by the heating agent, preferably oil, flowing in the heating pipe system IS (which is an endless spiral) welded onto the side- and bottom surfaces of the vessel. The heating agent is simultaneously heating the outside surface 132 of the heat chamber 13 and the heat uptaking part of the elements 141 under the bottom plate. The heating agent is connected to the heating pipe system 15 through the inlet stub 151 and the outlet stub 152. The heating agent is preferably circulated by a circulating pump and heated by a continuous operation boiler, which is operating making use of the heat released in the course of burning waste material. The only moving part of the recovering machine 1 is the press 11. The pressure required for melting the plastic waste is between 0.01 x 10⁶ and 3.0 x 10⁷ Pa (0.1 - 300 kp/cm²), preferably 2.4 x 10⁷ Pa (240 kp/cm²). The pressure presses the plastic waste to be recovered against the warm heat transferring surfaces, so the heat transferred to the different surfaces can be optimally utilized. At this pressure, the heat transferred by the heat transferring surfaces is enough for the recovering and melting of the miscellaneous plastic waste. The required pressure depends on the content and composition of the inputted plastic waste. The press 11 operates between two positions, the lower (basic) position and the upper (end) position, which is suitably controlled by and end-position switch, hi the upper end position there is a safety gap 18 situated between the press plate 111 and the breaking-through tips of elements 141 of the heat transmission block 14, so that the press plate 111 should not damage the prickling tips or cutting edges of the elements 141. As the type and composition of the inputted plastic waste can be different, that is, it is a mixture of different types of plastic wastes in different ratio, its melting point can not be unambiguously determined. However, it is important that, as a result of processing, the HBD of the plastic waste should be at least 0.5 kg/dm³. The temperature of the heat transmission surface is between 250-280⁰C, preferably 270⁰C. In the course of the processing it is not a requirement that the temperature of each component of the plastic waste should reach its melting point, it is only important that the volume of the miscellaneous plastic waste should be reduced radically, and the recovered and melted material obtained this way should be able to enter into the next step of processing. This can be determined experimentally.

So it is entirely or nearly entirely melted, recovered material that is pressed out through the discharge opening 17 from the recovering machine 1. However, this recovered material is not yet of the required homogeneity, and after cooling down, it can disintegrate just like the matrix materials obtained via the known methods. Therefore it is only the next step of processing that ensures and makes it possible to obtain the matrix material according to the invention, which can be performed by the homogenizing machine 2, where the internal mixing takes place. The homogenizing machine 2 adds heat, mixes the recovered material and exposes it to shear and compression stress in a way that the melted material is rearranged at the molecular level, that is, some old molecular links are broken, while new molecular links are established between the different materials.

The mixing drum 23 of the homogenizing machine 2 has preferably four rotors 233 having blades 2332, co-moving with the two pairs of parallel axles 2331 onto which they are mounted, and having a bearing holding sheet 2333 holding the axles 2331. The four rotors 233 in the mixing drum 23 are rotated by a motor through the shaft ends 24, which are preferably cardan shafts. The rotors 233 are preferably of rectangular shape and are moving on the axles 2331 at a constant speed, opposite to each other. The sides of the blades 2332 of the rotors 233 are preferably designed as edges. In order to obtain better mixing of the recovered material, the mixing drum 23 is heated by the heating system 232. Te heat transferring agent is preferably hot air that is directed into the mixing drum 23 through the first heating connection 2321 and let out through the second heating connection 2322.

The heating pipes 2323 are positioned around the surface of the rotors 233 in a way that they heat the rotors 233 at a temperature that ensures uniform mixing of the recovered material. The required heat insulation of the heating system 232 is solved by the heating cover 2324 of the mixing drum 23. The upper inside portion of the mixing drum 23 is suitably formed by two joining cylinders of approx. three-quarter size, which is opened above the horizontal connection line of the cylinders. The missing quarters of the cylinders are closed hermetically along the mantle and the end of the cylinders by the shutting piston 21 that can be moved by a driving-gear in a pipe of preferably rectangular section, in the lower position of the shutting piston 21. In the upper position of the shutting piston 21 it is shaped to act as a feed inlet 22 facilitating free feeding of the recovered material.

The operation of the homogenising machine 2 is as follows: in the upper position of the shutting piston 21 of special design, the recovered material, or the recovered material and the filling material or filling materials are inputted. The upper rotors 233 and lower rotors 233 heated with hot air are rotating in opposite direction in pairs. The blades 2332 of the rotors 233, directed in the required angle related to each other (preferably in 90°) mix and homogenize the recovered material with their edges formed on their sides. When mixing, the moving device 25, which is suitably a hydraulic system comprising a working cylinder 251 and a shaft 252, controls the displacing device 234 comprising a driving rod 2341, a displacing rod 2342 and a pressure plate 2343, co-moving with the rotor 233, in a way that the four displacing devices 234, sliding on the four driving rods 2341, are in a position outside the blades 2332 of the rotors 233. After the mixing has been finished, the moving device 25 controls the four displacing devices 234 in a way that each displacing device 234 slides on the respective driving rod 2341 to the blade 2332 of the rotor 233 co-moving with it, and encloses the blade 2332. Than, after the opening-closing element 2311 has been removed, the homogenised material around the circumference of the blades 2332 is pressed out through the outlet opening 231 by the displacing device 234, which is preferably a slotted cylinder, and the material pressed out is collected in a suitable vessel for further processing.

The homogenised material thus obtained is considered as matrix material, which is a final product to be processed in itself as well, however, its more important application is that it serves as a raw material for the production of composite materials, that can be utilised in many areas. If the matrix material is the final product, the homogenised material is inputted into a closed press instrument of the required form, a die-casting machine or an injection moulding device, in which it is cooled down and it obtains its final shape. In order to avoid deformation or suction effect, the pressure must be maintained until the end of the cooling process. Composite material can be obtained by adding the required quality and quantity of filling material(s) to the matrix material according to the invention. The filling materials can be added in the course of homogenizing the recovered material as well, in this case the composite material thus obtained is pressed and cooled as described above.

It is also possible and viable in practice that the raw material of the composite material is the previously processed, shaped and cooled matrix material, but in this case the matrix material must be melted before adding the filling materials, and the filling materials must be added to this melted matrix material. However, this kind of processing requires significant heat, which increases production costs significantly, so no cheap products can be manufactured this way, while it can be suitably and economically done by the apparatus according to the invention either in the form of pressed matrix material or in the form of composite material.

The apparatus according to the invention has realised its objectives, its advantages are as follows: the miscellaneous plastic wastes are processed without cutting, cawing, crushing, pellet-, crush- or other kind of homogenising, pre-cleaning, washing, drying or applying other material treatments, the recovered material is removed not by extruding but by pressing, the matrix material obtained is valuable in itself, it is chemically stable, cheap product suitable for further processing, possessing favourable physical properties such as high pressure-tightness and tensile strength, it can be manufactured manually or by machines, its density is preferably 0.6 — 1.3 g/cm3, it is UV resistant and resisting to weather, the composite material obtained by adding filling materials to the matrix material is also cheap, technologically valuable material suitable for being used as building material or wood-substitute, the miscellaneous plastic wastes can be processed by the apparatus comprising a recovering machine and a homogenizing machine in relatively few technological steps, effectively, economically, and in an energy-saving way.

Claims

1. Apparatus for processing miscellaneous plastic wastes to obtain matrix material or composite material, comprising a recovering machine (1) for melting the plastic wastes and a homogenizing machine (2) for further processing the recovered material coming from the recovering machine (1), where the recovering machine (1) comprises a press (11) having a press plate (111) and a press hydraulic system (112), a feed opening (12) between the press plate (111) and the upper part of the double-walled heat chamber (13) having an inside surface (131) and an outside surface (132), which feed opening (12) is suitable for feeding pre-selected plastic wastes, further, the recovering machine (1) comprises a heating pipe system (15) surrounding the heat chamber (13), provided with an inlet stub (151) and an outlet stub (152) suitable for letting in and out the heating agent, a heating agent tank (16) situated inside the heat chamber (13), and a discharge opening (17) for letting out the melted recovered material; the homogenizing machine (2) has a shutting piston (21) moved by a driving gear, in its upper position the shutting piston (21) acts as a feed inlet (22) for feeding the recovered material, while in its lower position, it acts as a closure of the mixing drum (23) which is open at the top, the mixing drum (23) has an outlet opening (231) at its bottom part, possessing an opening- closing element (2311), further, the mixing drum (23) the has a heating system (232) comprising a first heating connection (2321), a second heating connection (2322), heating pipes (2323) and a heating cover (2324), and has a shaft end (24) for power transmission, characterized in that the recovering machine (1) has an increased heat transmission surface designed as a heat transmission block (14) consisting of the inside surface (131) of the heat chamber (13) and the elements (141) situated between the inside surfaces (131) provided with prickling tips or cutting edges suitable for breaking through the inputted plastic wastes, the mixing drum (23) of the homogenizing machine (2) has at least two rotors (233) co-moving with the two parallel axles (2331) onto which they are mounted, having blades (2332) and a bearing holding sheet (2333), on the outer surface of the rotor (233) there is a displacing device (234) co-moving with the rotor (233), comprising a driving rod (2341), a displacing rod (2342) and a pressure plate (2343) facilitating displacement of the homogenised material, and the homogenizing machine (2) has a moving device (25) to control moving the displacing device (234) in and out.

2. The apparatus according to claim 1 characterized in that the mixing drum (23) of the homogenizing machine (2) has preferably four rotors (233), and the angle between the blades (2332) of the two adjacent upper rotors (233) and the two adjacent lower rotors (233), as well as the angle between the blades (2332) of the upper rotors (233) and the respective lower rotors (233) below them is preferably 90°.

3. The apparatus according to claim 1 or claim 2 characterized in that in the upper position of the press (11) which is preferably controlled by an end-position switch, there is a safety gap (18) between the press plate (111) and the breaking-through ends of the elements (141) of the heat transmission block (14).

4. The apparatus according to any of claims 1 - 3 characterized in that the size of the safety gap (18) is 0.05 - 0.5 mm, preferably 0.1 mm.

5. The apparatus according to any of claims 1 - 4 characterized in that the upper part of the mixing drum (23) is hermetically closed by a shutting piston (21) in its lower position, which shutting piston (21) is moved by a driving-gear in a pipe of preferably rectangular shape.

6. The apparatus according to any of claims 1 - 5 characterized in that the rotors (233) are preferably of rectangular shape and are moving on the axles (2331) at a constant speed opposite to each other.

7. The apparatus according to any of claims 1 - 6 characterized in that the sides of the blades (2332) of the rotors (233) moving opposite to each other are preferably designed as edges.

8. The apparatus according to any of claims 1 - 7 characterized in that the displacing device (234) is preferably a slotted cylinder.

9. The apparatus according to any of claims 1 - 8 characterized in that the moving device (25) is preferably a hydraulic system comprising a working cylinder (251) and a shaft (252).