RU2782067C2 - Method for production of products of polymer waste by extrusion-rolling-molding method and installation for its implementation - Google Patents

Abstract

FIELD: recycling.

SUBSTANCE: group of inventions relates to the field of recycling of polymer waste, namely to the production of long-length products in the form of different profiles of primary or secondary raw materials based on thermoplastic polymers by an extrusion-rolling-molding method. The method includes loading of raw materials into a hopper, extrusion, squeeze of heated mass to a molding base, molding of finished products. Moreover, perforated substrate is used as the molding base, which is rolled, and a thin layer of heated extrusion mass is squeezed on it from a device adjusting a width and a thickness of the product. Next, the thin face layer is aligned with ironing shafts, cooled, rolled to a roll. Then, the roll is unwound with perforated substrate facing upward, rolled, cut in length, a thick draft layer of molten extrusion mass is squeezed from the adjusting device, the layer is aligned, a surface is formed, while dyes are added to raw materials at the first extrusion stage. An installation includes a loading hopper, an extruder, and a molding device and consists of two lines, each of which includes a loading hopper, an extruder connected to the adjusting device located above a technological table and made in the form of a cylinder with a worm shaft located inside. The adjusting device has a longitudinal slit installed with the possibility of adjustment of its width and thickness. Perforated substrate is located on the technological table, several smooth rolling extending shafts are built in holes of the technological table, and ironing shafts are located behind the adjusting device above the technological table. At the same time, the second line of the installation additionally contains a knife for cutting, installed between two pairs of smooth extending shafts, and molding shafts located after ironing shafts.

EFFECT: possibility of the manufacture of flat and profile plates of a different shape, adjustable in thickness and length, with a face colored polymer layer, which reduces weight, saves material consumption, and reduces costs for the manufacture of the final products.

2 cl, 3 dwg

Description

SUBSTANCE: group of inventions relates to the field of polymer waste processing, namely, to the production of long products in the form of various profiles from primary or secondary raw materials based on thermoplastic polymers (thermoplastics).

The invention can be used in the construction industry for the production of various building products, namely long products in the form of flat profiles and plates from primary or secondary raw materials based on thermoplastic polymers (thermoplastics). Installations for the continuous production of long-length profile products from composite materials are subject to increased requirements for providing them with an increased quality of manufacturing end products with uniformity, continuity, improved appearance, a given reinforcement structure, durability, strength and reliability, ease of manufacture, maintenance at minimal cost. labour, economy and competitiveness.

A device is known (R.V. Torper, M.S. Akutin. Equipment for plastics processing plants, Moscow, "Chemistry", 1975, p. 93), consisting of a drive worm shaft (auger), a housing (container) with an internal longitudinal a cavity for processed raw materials and a loading hopper. Electric heating elements are installed outside the housing. The body ends with a forming head with a channel, the cross section of which corresponds to the shape of the product. Behind the head are devices for cooling the resulting profile and straightening it by stretching.

A device for producing profile products from thermoplastic polymeric materials by continuous injection molding is known (I.I. Dmitrienko, A.S. Naumenko. Proceedings of the conference held in the framework of the 3rd international exhibition on waste management WasteTech-2003, Moscow, June 3-6, 2003). The head of this device is also an extruder in the form of a heated body with a hopper and a screw. At the end of the housing cavity there is a nozzle open towards the elongated matrix, the cavity of which in cross section has the profile of the resulting product. At the exit from the matrix there is a mechanism for creating a variable counterpressure in the cavity of the matrix and for pulling the product.

An extruder for processing secondary polymers is known (RU156851 U1; IPC B29C 47/62, B29C 47/64, B29C 47/08; publ. 20.11.2015). The extruder is designed for processing secondary polymeric materials and includes a housing, a gripper, and a screw. In the dosing zone, the auger is made of two successively located conical and cylindrical sections. The inner walls of the housing in the compression zone are made in the form of a multi-channel mixing coil, which are placed along the housing cylinder and form the inlet channel, the outlet channel and the gap of the barrier stage.

The use of an extruder in the processing of combined secondary mixtures makes it possible to combine preparatory operations (filling, mixing, granulation) and the operation of obtaining new high-quality products by extrusion.

The disadvantage of the above-described known devices is the increased swelling of the extrudate at the exit from the die due to the discrepancy between the temperature and speed parameters of extrusion. In addition, when processing secondary polymers, foreign inclusions (impurities) are not excluded. Hence the low mechanical strength due to uneven mixing.

A known installation for the continuous production of long shaped products from composite materials by the method of extrusion thermoforming through a spinneret (RU2170175; IPC V29S 55/30, V29V 15/14; publ. 10.07.2001).

This plant allows the production of blanks of products, such as strands of strands or threads and strips of longitudinal material (hollow spacer elements for insulating glazing or structural elements used respectively in door, window frames or frame structures for building needs). It is not possible to produce wide two-layer products.

A known method of molding long hollow products from powdered and plasticized masses and a device for its implementation 2492965; IPC B22F 5/12, B29C 47/20; publ. September 20, 2013).

However, this method is intended only for forming hollow long-length products from powder or plasticized masses and there is no possibility to adjust the product in thickness.

A known press plant for the production of products from polymeric materials for the production of long products in the form of strips, rods and profiles from primary or secondary raw materials based on thermoplastic polymers (thermoplastics) (RU2329142; IPC B29C 43/00; publ. 20.07.2013).

However, in a known installation, products are obtained by pressing and are limited not only in width, but also in length, which is due to the stroke of the punch and the intake of raw materials in one cycle, and to produce products of different shapes and sizes, it is necessary to change the matrix each time, which complicates the device.

Known press plant for the production of products from polymeric materials (RU No. 2329142; IPC V29S 43/00; publ. moving along the axis of the press through the hopper and inside the working cavity of the container, the drive of the punch, the receiving table. The container is equipped with internal channels for the liquid heat carrier located near the surface of its working cavity. The cavity is made in the form of a rectangular slot. On the side opposite to the container inlet, it is adjoined by a matrix with one or more working channels inscribed in the contour of the container slot and forming a section of the pressed products. Behind the matrix there is a melting and exhaust device for finishing products.

The disadvantages of the known installation include one heating zone of the material, which leads to uneven heating of the raw material. Also, there is an accumulation of the mixture on the side surface of the punch, which negatively affects the quality of the produced material.

The closest analogues were chosen the method and device described in the invention (RU 2433041 C2; IPC B29C 47/16; publ. 11/10/2011) a device for extruding strip or tape blanks from thermoplastic plastic, as well as a method for extruding such a blank. The device contains an extrusion head for extruding strip or strip blanks from thermoplastic plastics, as well as a composite molding tool for processing strip or strip blanks during the first heating using gas pressure and/or vacuum into a plastic product. Moreover, the melt exit from the extrusion head is made in the form of a slotted nozzle moving across the direction of extrusion, passing in a straight line. In this case, the slotted opening of the nozzle is directly limited by several segments, which are installed independently of each other across the direction of extrusion and provide stepwise regulation of the size and/or width of the slotted opening of the nozzle.

The method of extrusion blow molding of plastic products according to RU2433041 provides for the plasticization of thermoplastic plastic in an extruder, bringing it to the slotted hole of the nozzle of the extrusion head, adjusting the size of the slotted hole of the nozzle, and processing the extrudate inside the molding tool.

The disadvantage of the known invention is that it is intended only for the processing of plastics. In addition, the blanks of the product formed in the molding tool, when extruded from it, will not hold their shape, since they are still in a thermoplastic state. But at the same time, the workpieces cannot be cooled to a solid state in the molding tool, since the extrusion process is continuous. Also, a certain disadvantage is the limited length of the blanks, due to the length of the molding tool.

The objective of the invention is to obtain high-quality two-layer products in the form of flat and shaped plates of various shapes, obtained from a mixture of quartz sand and plastics from household waste of polymeric materials (high-pressure polyethylene, low-pressure polyethylene, plastic bottles) and covered with a film from a mixture of high-pressure polyethylene with coloring pigments.

The technical result from the use of the invention is the possibility of manufacturing flat and profiled plates of various shapes, adjustable in thickness and length, with a front painted polymer layer, which reduces weight, saves material consumption, incl. dye, and reduces the cost of manufacturing the final product.

The specified technical result is achieved by the fact that in the method for the production of products from polymer waste by the extrusion-rolling-forming method, including loading raw materials into a bunker, extrusion, squeezing the heated mass onto a forming base, molding finished products, according to the invention, a perforated substrate is used as a forming base, which is rolled and a thin layer of heated extrusion mass is squeezed onto it from a device that regulates the width and thickness of the product, the thin front layer is leveled with ironing rollers, cooled, rolled up, then the roll is turned with the perforated substrate up, rolled, cut along the length, squeezed out a thick draft layer molten extrusion mass from the control device, level the layer, form the surface, while at the first stage of extrusion dyes are added to the raw material.

The specified technical result is also achieved by the fact that in the installation for the production of products from polymer waste by the extrusion-rolling-forming method, including a loading hopper, an extruder, a forming device, according to the invention, the installation consists of two lines, each of which includes a loading hopper, an extruder connected to the control device located above the technological table and made in the form of a cylinder with a worm shaft located inside, the control device has a longitudinal slot installed with the possibility of adjusting its width and thickness, a perforated substrate is located on the technological table, several smooth rolling pulling rollers, behind the adjusting device above the technological table there are ironing rollers, while the second installation line additionally contains a cutting knife installed between two pairs of smooth pulling rollers, and forming rollers, located nye after ironing rollers.

Distinctive features of the claimed group of inventions are:

- production of finished products on two lines in two stages, which makes it possible to obtain high-quality two-layer products in the form of flat and profile plates of various shapes, covered with a film from a mixture of polymer waste with coloring pigments;

- use of a perforated substrate as a forming base, which makes it possible to obtain finished products from layers: a thin front painted, thick draft layer and their connecting layer - a perforated substrate. This provides a reduction in the weight of the product, saving material consumption, incl. dye, reducing the cost of manufacturing the final product;

- the presence of a control device having a longitudinal slot installed with the possibility of adjusting its width and thickness, which makes it possible to obtain products of different thicknesses and widths;

- the installation of a cutting knife at the second stage of extrusion ensures the regulation of the length of finished products, the installation of forming shafts provides the necessary configuration of the final products.

In the claimed invention, it is proposed to manufacture products from polymer waste, consisting of a thin front colored layer, a draft layer, a perforated substrate, and to abandon molds. Cardboard can be used as a perforated backing. These distinctive features make it possible to obtain durable products due to the presence of two working layers and a cardboard binding them; the possibility of variation in length, width, thickness; a significant reduction in the cost of production due to a significant increase in productivity; the use of polymer waste and the rejection of expensive molds used in pressing; dye savings due to the fact that the dye is used only for a thin front layer.

Additional adjustable slotted part of the adjusting device makes it possible to obtain products of different widths and thicknesses; to obtain the necessary excess pressure on the melt in order to achieve the required density and remove bubbles in the finished product, and the product molding device creates the necessary configuration of the final product.

The method for the production of products from polymer waste by the extrusion-rolling-forming method includes two stages. At the first stage, a thin front layer with a dye is formed, and at the second stage, a thick draft layer. In the quality of the feedstock at the first stage, waste products from high-density polyethylene and a dye are used, which are loaded into the hopper of the first extruder. Next, the mixed raw material is fed into the extruder, where it is heated and brought to an elastic state. The polymer melt from the exit of the extruder is forced into the control device. A perforated substrate is rolled on the technological table and a thin layer of heated extrusion mass is squeezed onto it through the adjustable thickness and width of the longitudinal slot of the regulating device. Then the substrate with the front layer is leveled and cooled. Cardboard is used as a perforated substrate. From the side of the applied colored film, the cardboard is rolled into a roll, which is the front part of the manufactured product, and also acts as a substrate in the second stage and has sufficient flexibility and elasticity for subsequent molding.

As a feedstock at the second stage, a mixture of polymeric wastes is used - high-pressure polyethylene, low-pressure polyethylene, plastic bottles, etc., which play the role of binders and filler in the form of quartz sand, slag in different proportions. Said feedstock is loaded into the preheating bin of the second extruder. Next, the heated raw material is fed into the extruder, where it is also brought to an elastic state, but at a different temperature, depending on the composition of the polymer waste. The melt of the composite material from the extruder outlet is forced into the control device, from where a thick draft layer is squeezed out through the longitudinal slot onto the perforated side of the substrate with a thin front layer obtained at the first stage, which is pre-rolled on the technological table and cut to length.

Next, the layer is leveled with ironing rollers, excess raw materials are removed and the required shape is formed. Then the finished product is stored.

The claimed device is illustrated by drawings, where in Fig. 1 schematically shows the installation, in Fig. 2 is section A-A of FIG. 1 of the first installation line, in FIG. 3 is section A-A of FIG. 1 second installation line.

The proposed installation for the production of products from polymer waste using the extrusion-rolling-forming method contains two lines, each of which includes a hopper 1, an extruder 2 with three heat-heating elements 3 to achieve the thermoplastic state of the feedstock (see Fig..1 ). Through the connecting element 4, the extruder 2 is connected to the control device 5, made in the form of a cylinder with a worm shaft located inside (not shown in the figure). The device 5 has a longitudinal slot 6 installed with the possibility of adjusting its width and thickness by means of diaphragms. The device 5 is located above the technological table 7, on which there is a perforated substrate, which is used as cardboard (not shown in the figure). In the openings of the technological table 7 are built several smooth rolling pulling shafts 8 (see Fig. 2). Behind the control device 5, above the technological table 7, there are ironing rollers 9. The extruder 2 is connected to the electric motor 10 through a reduction gear 11. Smooth pulling rollers 8 and ironing rollers 9 are connected to the electric motor 12 through a reduction gear 13.

The second line of the proposed installation additionally contains a knife 14 for cutting, installed between two pairs of smooth pulling rollers 8, and forming shafts 15 located after the shafts 9. Smooth pulling rollers 8, ironing rollers 9 and forming shafts 15 are connected to the electric motor 12 through a reduction gear 13 .

The claimed device works as follows.

On the first line of the installation, the front layer of products from polymer waste is formed. The mixture is placed in the hopper 1 where it moves under the action of the screw and at the same time the mass is further heated to a thermoplastic state in three heating zones to temperatures of 80°C, 120°C and 160°C using three heat-heating elements 3. Extruder screw 2 driven by an electric motor 10. Since the speed of rotation of the motor shaft is very high, a reduction gear 11 is used to reduce the speed of rotation of the motor shaft. In this case, the speed of rotation of the motor screw is selected experimentally in order to obtain a thermoplastic mass at the end of the extruder. The thermoplastic mass in the form of a polymer melt with a dye through the connecting element 4 enters the control device 5, where excess pressure is created to remove the "bubbles" and seal the melt. From the regulating device 5, the thermoplastic mass is extruded in a thin layer through a narrow longitudinal slot 6 onto a flexible, elastic workpiece, in this case, perforated cardboard, which is preliminarily moved by means of rolling, pulling rollers 8 along the technological table 7. The length and width of the longitudinal slot 6 can be adjusted using diaphragms, as a result of which the width and thickness of the front layer of the product varies. Using the control panel (not shown in Fig.) motor 12 with reduction gear 13 regulate the speed of rotation of the rolling pulling shafts 8, which also allows you to vary the thickness of the front layer of the product. Next, the front layer of products is leveled with ironing rollers 9, cooled. From the side of the applied colored film, the cardboard can be wound into a roll and is the front part of the manufactured product. This face layer is very thin (up to 1 mm) and therefore has sufficient flexibility and elasticity for subsequent molding.

On the second line of the proposed installation, a rough layer of products from polymer waste is formed. In the hopper 1 of the second line, the mixture is preheated and mixed. In the manufacture of the draft layer, a mixture of polymer waste with a melting point of up to 250 ° C (high-density polyethylene, low-density polyethylene, plastic bottles, etc.) is used with quartz sand or slag in different proportions. The preheating temperature depends on the composition of the components and should lead to a softening state of the mixture. The heated and mixed mixture is fed into the second extruder 2 and, as in the case of making the finishing layer, the mixture passes through three heating zones with temperatures depending on the specific components, until the initial melting temperature of the most refractory component is reached. Next, the melt is fed into the body of the control device 5 of the second line. In contrast to the device 5 of the first line, the width of the longitudinal slot 6 of the second line is larger. This is due to the fact that the thickness of the rough layer is up to several centimeters, which is much greater than the thickness of the finishing layer, and therefore it is necessary to extrude a larger volume of the melt. A thin front layer, obtained on the first line, and acting as a product substrate, is pulled along the technological table 7 using shafts 8. Next, the product with the substrate of the desired length is cut using a knife 14. A thick draft layer is squeezed out of the control device 5 through the slot 6 melted composite mixture on the cardboard from the perforated side, the desired thickness of the product is formed using ironing rollers 9. Then the product passes through the forming rollers 15 to form the desired shape. Then the finished product is stored.

Claims (2)

1. A method for the production of products from polymer waste by the extrusion-rolling-forming method, including loading raw materials into a bunker, extrusion, squeezing the heated mass onto a forming base, molding finished products, characterized in that a perforated substrate is used as a forming base, which is rolled and extruded a thin layer of heated extrusion mass is applied to it from a device that regulates the width and thickness of the product, the thin front layer is leveled with ironing rollers, cooled, rolled up, then the roll is unfolded with the perforated substrate up, rolled, cut along the length, a thick draft layer of the molten extrusion mass is squeezed out of control device, level the layer, form the surface, while at the first stage of extrusion, dyes are added to the raw material. 2. Installation for the production of products from polymer waste by extrusion-rolling-forming method, including a loading hopper, an extruder, a forming device, characterized in that the installation consists of two lines, each of which includes a loading hopper, an extruder connected to a control device located above the technological table and made in the form of a cylinder with a worm shaft located inside, the control device has a longitudinal slot installed with the possibility of adjusting its width and thickness, a perforated substrate is located on the technological table, several smooth rolling pulling shafts are built into the holes of the technological table, behind the adjusting device above the technological table is the ironing rollers, while the second installation line additionally contains a cutting knife installed between two pairs of smooth pulling rollers, and forming rollers located after the ironing rollers.

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