JP4817983B2 - Recycling waste plastic to thin products - Google Patents

Description

  The present invention relates to a method for recycling a thin film product using waste plastic separated and collected from container and packaging plastic, which is general waste.

  FIG. 12 shows the total amount of waste plastic discharged and the flow in Japan up to the recycling process. The numerical values are those of 2004, and the numbers do not necessarily match.

  The total amount of waste plastic is about 1,000,000 tons, of which about 880,000 tons are generated as product production and processing loss, and 1.11,100,000 tons are generated as waste of used products. In addition, industrial waste is 4.88 million tons, and general waste is 5.13 million tons (34,000 tons in Hiroshima Prefecture) of the total amount of waste plastic. Of these waste plastics, 42% are discarded and unused, 39% are thermally recycled, 3% are chemically recycled, and 16% are material recycled, approximately half The neighborhood is currently disposed of in landfills. Thermal recycling is a processing method for recovering heat using waste plastic as a fuel for combustion, and cannot be used again as a resource. Chemical recycling is a treatment method in which waste plastic is pyrolyzed to obtain cracked oil and raw material monomers. Material recycling is a processing method in which collected waste plastic is washed, returned to raw material pellets, re-injected and reused, and can be reused as a product many times. .

  Currently, it is obliged to recycle container plastics discharged under the Containers and Packaging Recycling Law. Plastic containers and packaging waste generated in Hiroshima Prefecture is subjected to thermal recycling and material recycling. Hiroshima Recycling Center Co., Ltd. accepts 28,000 tons of plastic waste from containers and packaging from local governments in Hiroshima Prefecture. This is about 80% of 34,000 tons of plastic containers and packaging waste generated in Hiroshima Prefecture (FY2016). Of these plastic wastes, polyolefin resins called polypropylene (PP) and polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS) are separated, washed, and granulated for each type of resin and collected. About half of the packaging containers are material recycled. Others are mainly processed by thermal recycling.

  These recycled plastic pellets of olefin resin that have been recycled are sold at a low price, but their use is mainly for heavy-duty products such as civil engineering materials, agricultural materials, and transportation pallets. This is because foreign materials are contained in the recycled olefin resin, and the resin base material is not uniform, so that it is very difficult to process into a thin product.

Thick products are not used in many fields as plastic products. Rather, plastics are thin and light, and there is a high demand for products and it is easy to add value. For this reason, there is an increasing demand for using the recycled plastic pellets in bags and sheets. The recovered polyolefin resin in the packaging container is primarily made of film grade, so it is considered that it can be easily reused for relatively thin products due to the inherent processing performance of the resin.
JP 2000-326407 A

  In Japan, 230,000 tons of plastic garbage bags are consumed, of which 93,000 tons (40.4%) of polyolefin resin garbage bags produced domestically. The market size of plastic garbage bags is about 92 billion yen. On the other hand, material costs account for more than half of the production cost of garbage bags, so material costs should be reduced if the performance can be reproduced by an inexpensive method using recycled plastic, which is about one-tenth the cost of virgin materials. Can do. For this reason, the garbage bag with sufficient product competitiveness can be provided to the world. Further, since recycling from bag to bag can be repeated between thin products, it is the most efficient method for material recycling. There is a need to develop recycling methods between these thin products.

  In the invention disclosed in Patent Document 1, an agricultural film using polyethylene as a base resin exposed to the atmosphere in Example 1 for 1 year or more was collected, pulverized, fluffed, washed, dehydrated, dried, and granulated. Later, Nippon Bolchem Co., Ltd.'s lubricant masterbatch was dry blended and the film was regenerated on a multilayer blown film forming machine. However, this method does not reach the point where a single-layer garbage bag can be recycled, and the garbage bag cannot be recycled into the same garbage bag.

  The present invention has been made in view of the above-described problems, and realizes a method for producing a waste bag molding grade pellet of olefin resin using 80% or more of recycled plastic and recycling it to a thin product such as a garbage bag. is there.

  The present invention includes a step of separating and collecting waste plastic from a container and packaging plastic, which is a general waste, a step of kneading the waste plastic and a modifying resin, finely and almost uniformly dispersing both, and granulating the waste plastic. And a step of putting the particles of the plastic and the modifying resin into an extruder and forming into a thin film.

  Further, in the present invention, the waste plastics are mainly composed of polyethylene (PE) and polypropylene (PP) and occupy 70% by weight or more, and the remainder includes a small amount of different plastics such as polystyrene and other small amounts of different materials. It is characterized by that.

  Furthermore, the present invention is characterized in that, in the step of separating and collecting the waste plastic, the container and packaging plastic is pulverized, separated and collected, and then washed to remove odors generated from food residues and the like.

  Furthermore, the present invention is characterized in that the container-wrapped plastic is treated with an activator at a temperature of 40 ° C. to 60 ° C. for about 5 minutes, and then dehydrated and washed with water to reduce odor.

  Furthermore, in the granulating step, the present invention comprises virgin PE or PP as the modifying resin, recycled polyethylene (regenerated PE) or recycled polypropylene (regenerated PP) recovered from industrial waste, and thermoplastic plastic. It is at least one resin selected from the group.

  Furthermore, the present invention is characterized in that the amount of the modifying resin is 30% by weight or less.

  Furthermore, in the granulating step, the present invention quantitatively inputs the waste plastic and the modifying resin into an extruder, and kneads while melting at 180 ° C. to 250 ° C. to obtain polyethylene (PE), It is characterized in that polypropylene (PP), the modifying resin, different plastics and other small amounts of different materials are dispersed on a micron order to make a uniform material macroscopically.

  Furthermore, the present invention is characterized in that a compatibility agent for a polymer is added together with the modifying resin to improve the compatibility between the dissimilar material and the polyolefin polymer.

  Furthermore, the present invention is characterized in that in the granulating step, undissolved resin and different materials are removed with a filter having a sieve opening of 400 μm to 250 μm.

  Furthermore, the present invention uses an inflation molding extruder in the step of molding into a thin film, and regarding the molding conditions, the preset temperature of the extruder is set to 180 ° C. to 210 ° C., and the preset temperature of the inflation die is set to 200 ° C. to 210 ° C. It is characterized by that.

  In the present invention, the waste plastic and the modifying resin are kneaded and both are finely and almost uniformly dispersed and granulated, so that a pellet capable of forming a thin product can be realized, and the waste plastic can be recycled to the thin product. Can be established.

  Further, in the present invention, since the recovered plastic is 70% or more by polyethylene (PE) and polypropylene (PP), it can be easily formed into a thin film or sheet. In particular, it is possible to realize the recycling from thin films or bags to thin products again.

  Furthermore, in the present invention, waste plastic is separated and recovered and then washed to remove odors generated from food residues and the like, so that there is an advantage that odors do not become a problem even if they are recycled to thin products.

  Furthermore, in the present invention, if recycled polyethylene (recycled PE) or recycled polypropylene (recycled PP) recovered from industrial waste is used as the modifying resin, the recycling rate can be improved to 100%, and the tensile strength of thin products can be improved. The JIS standard can be cleared.

  Furthermore, in the present invention, when a compatibilizing agent is selected as the modifying resin, the waste plastic can be raised to 95% by weight, and recycling can be realized with almost only the waste plastic.

  Furthermore, in the present invention, a thin product can be molded even if the amount of the modifying resin is 30% by weight or less.

  Furthermore, in the present invention, in the granulating step, polyethylene (PE), polypropylene (PP), the modifying resin, different plastics and other small amounts of different materials are in micron order by kneading with a twin screw extruder. It is possible to disperse to make a uniform material macroscopically and to supply pellets suitable for forming a thin product.

  Furthermore, in the present invention, a polymer compatibilizer is added together with the modifying resin, and the tensile strength of the thin product to be molded can be increased by improving the compatibility between the dissimilar material and the polyolefin polymer, There is no tearing during inflation molding.

  Furthermore, in the present invention, in the granulation step, the undissolved resin and the different materials are removed with a filter having a sieve opening of 400 μm to 250 μm, so that the thickness of the thin product at the time of inflation molding can be reduced to 100 to 30 μm.

  Further, in the present invention, in the step of forming into a thin film, an inflation molding extruder is used, and regarding the molding conditions, the preset temperature of the extruder is set to 180 ° C. to 210 ° C., and the preset temperature of the inflation die is set to 200 ° C. to 210 ° C. Thus, a good film can be continuously formed.

  FIG. 1 is a process diagram for explaining each process of the method for recycling waste plastic to a thin product according to the present invention. FIG. 2 is a process diagram illustrating detailed steps of the separation and recovery process. FIG. 3 is a block diagram illustrating odor measurement after cleaning according to the present invention. FIG. 4 is a pie chart illustrating the distribution of the types of containers and packaging plastic waste collected. FIG. 5 is a characteristic diagram showing the results of measuring the chemical composition of the collected plastic fluff using a gas chromatograph mass spectrometer (GCMS). FIG. 6 is a block diagram schematically showing a twin-screw extruder used in this embodiment. FIG. 7 is a conceptual diagram showing the state of the polymer blend of this embodiment. FIG. 8 is a characteristic diagram showing the degree of improvement in film forming performance by the filter of this embodiment. FIG. 9 is a block diagram schematically showing a manufacturing apparatus for forming a film according to an embodiment of the present invention. FIG. 10 is a characteristic diagram showing the molding performance of recycled pellets mixed with waste plastic from which recycled LLDPE has been recovered. FIG. 11 is a characteristic diagram showing an example of the mechanical strength of the formed film. FIG. 12 is a block diagram showing the total amount of waste plastic discharged and the flow in Japan up to the recycling process.

  In the embodiment of the present invention, as shown in FIG. 1, a step of separating and recovering waste plastic from container and packaging plastic, which is a general waste (separation recovery step), and kneading the waste plastic and the reforming resin to make both fine And a process of granulating almost uniformly dispersed (granulation process) and a process of forming the waste plastic and the modifying resin granules into an extruder and forming into a thin film (thin material molding process) Yes.

  In the fraction collection step, as shown in FIG. 2, the plastic fluff is taken out through the steps of crushing, separating, washing and drying the waste bale.

  The waste bale is a separate collection of plastic bottles and food trays from which plastic bottles and food trays have been removed. The waste bale is then compressed and packed in a bowl with a binding material.

  The waste bale obtained from the garbage disposal site is loosened by loosening the binder, and roughly sorted to remove large pieces of wood, ceramic pieces, metal pieces, etc. other than plastic that are mixed by hand. Thereafter, if necessary, foreign matter such as small pieces of wood, ceramic pieces, metal pieces, etc. may be removed by automatic sorting.

  Subsequently, everything that is not separated and removed by hand sorting is crushed by a pulverizer, and garbage bags and the like are crushed to a size of about 30 mm square. Plastic crushers include a twin-screw crusher, a single-screw crusher, and a rotary cutter.

  After that, in the separation, the waste veil crushed in the water of the processing tank by the specific gravity separation method is put in, and the polyolefin resin (polyethylene and polypropylene) used for garbage bags etc. floats up because the specific gravity is 1 or less. Since the specific gravity of plastic (for example, polyamide resin) and metal, rubber, or inorganic substance is 1 or more, it sinks to the bottom of the processing tank and is separated.

  In washing and drying, washing is performed to remove oils and fats, food residues, and the like adhering to the container / package plastic waste. Odors derived from proteins such as oils and fats and food residues adhering to containers and packaging plastic waste are the main causes of the final product, and it is essential to remove them in the initial stage.

  A flow chart of washing and drying is shown in FIG. The odor was measured using an odor sensor (TUOC detector XP-339V). The base gas used was air treated with activated carbon or silica gel. First, the odor was measured when a collection fluff (sampled plastic trash from a container and subjected to primary cleaning with water) as a sample was left in a plastic container for a whole day and night. The fluff is obtained by finely cutting a collected plastic film or sheet to about 30 mm.

  Next, 400 g of the recovered fluff was placed in a net container, and the detergent was put in a laundry test machine for clothing, and washed in 20 L of hot water at 60 ° C. for 5 minutes. After dehydrating for 2 minutes, rinsing was again performed in 20 L of hot water at 60 ° C. for 5 minutes. The washed sample was dehydrated for 2 minutes and dried at 80 ° C. for 20 minutes. This sample was left in a plastic container for a whole day and night to measure the odor.

  Table 1 shows the results of how much odor was reduced by this washing.

The industrial detergents shown in Table 1 are selected from anionic surfactants, nonionic surfactants, both nonionic surfactants, and cationic surfactants. That is, A does not contain an activator, the main component is a chelating agent EDTA (ethylenediaminetetraacetic acid), B is a main component is polyoxyethylene alkyl ether (nonionic surfactant), and C is a main component Is polyoxyethylene alkyl ether, D is polyalkylphenyl ether (nonionic surfactant) as the main component, and E is N-acylamidopropyl-N, N-dimethylammoniobetaine (both non-ionic surfactants). An ionic surfactant). The cleaning test results are summarized in Table 1 below.

洗剤としては泡立ちの発生しないＣ，Ｄ，Ｅが使いやすいことが分かった。また、臭気は47.5〜53.5%の除去率であった。この結果、臭気は半減できるので、薄物製品にリサイクルしてもゴミ袋などに用いれば問題は少ないことが分かった。

It was found that C, D, and E, which do not cause foaming, are easy to use as detergents. Moreover, the odor was 47.5-53.5% removal rate. As a result, since the odor can be halved, it has been found that even if it is recycled to a thin product, there are few problems if it is used in a garbage bag.

  As described above, after drying, it is recovered as a waste plastic fluff.

  FIG. 4 is a pie chart illustrating the distribution of the types of containers and packaging plastic waste collected. As is apparent from this graph, 53% of bags and films, 22% of containers, 5% of trays used for food packaging, 6% of bottles, 2% of packing cushioning materials, solid plastics such as tableware 6%, metals and others are 8%. Therefore, if this bag or film occupying more than half is recycled and returned to the same bag or film, the efficiency of recycling will be extremely improved.

Table 2 shows the analysis results of the types of plastic contained in the waste plastic obtained by separating and recovering the polyolefin resin from the container and packaging plastic shown in FIG. The content is 32 to 47% by weight of polypropylene, 26 to 27% by weight of polyethylene, 19 to 35% by weight of polystyrene, 0 to 5% by weight of polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinyl chloride ( PVDC) is assumed to be 3-6% by weight. Polyethylene and polypropylene are mainly used for bags and films, polystyrene is used for food trays, PET is used for bottles, and PVC and PVDC are used for food packaging wraps.

これから容器包装プラスチックゴミの５３％を占める袋やフィルムを分別回収できれば、ポリオレフィン系樹脂（ポリエチレンとポリプロピレン）を効率よく回収できることが明白である。

From this, it is apparent that polyolefin resins (polyethylene and polypropylene) can be efficiently recovered if bags and films that occupy 53% of container-wrapped plastic waste can be separated and recovered.

  The result of having measured the chemical composition of the collect | recovered plastic fluff in FIG. 5 with the gas chromatograph mass spectrometer (GCMS) is shown. In FIG. 5, the horizontal axis represents time, and the vertical axis represents peak intensity. It can be seen that the plastic fluffs recovered from this are mainly polyethylene and polypropylene, but also contain polystyrene. Therefore, it turned out that it is necessary to set melt | dissolution temperature as high as about 220-240 degreeC. The melting point of polyethylene is 107 ° C to 135 ° C, the melting point of polypropylene is 167 ° C, and the melting point of polystyrene is 230 ° C.

  Next, the granulation step will be described with reference to FIG. In this step, the waste plastic and the modifying resin are kneaded and both are finely and almost uniformly dispersed and granulated.

  FIG. 6 is a block diagram schematically showing a twin-screw extruder used in this embodiment.

  The twin-screw extruder 1 used in the present embodiment includes a barrel 3 in which an eyeglass-shaped barrel hole 2 is formed, and two screws 4, 4 provided in the barrel hole 2 so as to rotate parallel to each other. And a drive motor 5 for driving the screw 4, a first material quantitative feeder 6, a second material quantitative feeder 7, a third material quantitative feeder 8 provided on the upper surface of the barrel 3, and a barrel 3. A stainless steel wire mesh 9 serving as a filter, a die 10 for delivering a melted resin, a cooling tank 12 for cooling a strand 11 of resin delivered from the die 10, a pelletizer 13 for finely slicing the strand 11, and a pellet 14 for molding It consists of a collection tray 15 to be collected.

  The two screws 4 and 4 are rotated by the drive motor 5 so as to mesh with each other, and the resin is pushed in the axial direction by the rotation and pushed out from the die 10 at the end of the barrel 3.

  The first material quantitative feeder 6 is filled with a waste plastic fluff that has been collected and washed and dried, the modifying resin is introduced from the second material quantitative feeder 7, and the third material quantitative feeder 8 receives a compatibilizer. Is put.

  The stainless steel wire net 9 removes foreign matters such as unmelted thermosetting resin and wood chips so that the thin bag or film of about 30 to 100 μm which is damaged due to the last blow molding is not torn. Yes.

  A strand 11 having a diameter of 3 to 5 mm is taken out from the die 10, cooled, and then sliced into a length of about 2 mm by a pelletizer 13 to form a molding pellet 14.

  Waste plastics produced by mechanically separating and collecting large amounts of container and packaging plastic waste contain a wide variety of materials as shown in FIG. 4, and they are non-uniform with relatively large particle sizes. Since the molten resin extruded from the die at the time of the last inflation molding has different melt properties (viscosity, melt tension, etc.) even in the same type of resin, the shape of the inflation tube Further, the film thickness fluctuates significantly and the film forming width and thickness become unstable. Furthermore, if there is a large undissolved foreign matter, the inflation tube is pressurized, so it cannot be formed due to tearing.

  These problems are solved by reforming the recycled resin by the polymer blend performed using the above-described twin-screw extruder 1.

  The waste plastic and the modifying resin are quantitatively charged from the first and second material quantitative feeders 6 and 7 into the kneading twin-screw extruder described above, and are kneaded while melting at 180 to 250 ° C. Polyethylene (PE), polypropylene (PP), modifying resins, and different types of thermoplastic resin that cannot be removed as foreign substances are all thermoplastic resins, and each resin is dispersed from submicron to micron order with this twin-screw extruder. As a result, the material is microscopically uniform but is macroscopically uniform. In addition, when a non-reactive compatibilizing agent is used, the compatibility between the dissimilar material and the polyolefin polymer is improved, and when a reactive compatibilizing agent is used, chemical bonding is performed. Thereby, melt physical properties and mechanical strength are improved. Non-reactive compatibilizers include styrene / ethylene / butylene / styrene block copolymers, polyethylene / polymethyl methacrylate block copolymers, polyethylene / polystyrene graft copolymers, polyethylene / polystyrene block copolymers, etc. Examples of the reactive compatibilizer include maleic anhydride-grafted styrene / ethylene / butylene / styrene block copolymers, maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, and ethylene / glycidyl methacrylate copolymers.

  As the reforming resin, virgin olefin resin pellets or olefin resin plastic processing waste (represented as production processing loss in FIG. 11) separated and recovered as industrial waste is used. Clean Giken Co., Ltd. accepts 600 tons (16 years) of plastic from industrial waste, mainly in the automobile and information and communications industries, and performs material recycling. Such industrial waste is still unused, the type of resin is known, and the performance is stable and relatively easy to recycle. Therefore, the cost is lower than that of virgin olefin resin pellets, which contributes to the improvement of the recycling rate.

  In this step, the polyamide mixed as polyethylene, polypropylene, polystyrene, nylon or polyester scraps is kneaded by the above-described extruder into a polymer blend that is uniformly and finely mixed. The polymer blend means a mixture of two or more types of polymers or copolymers, and is further refined and improved in performance by using processing conditions of a extruder, a compatibilizing agent, and the like.

  FIG. 7 shows a conceptual diagram of the polymer blend of this embodiment. It is apparent that the size of 500 μm or more before being kneaded by the extruder is fine and evenly mixed to the order of several μm after kneading. This can be realized by raising the temperature of the barrel of the extruder to 180 ° C to 250 ° C to a temperature at which polystyrene and polyamide are melted.

  Fig. 8 shows the degree of improvement in film forming performance with a stainless steel wire mesh filter. Mechanical strength and film forming performance can be further improved by removing undissolved thermosetting resin and different materials (wood pieces, metals, inorganics) with a fine sieve (stainless steel net).

  Since the manufactured bag is a thin material of about 30 to 100 μm, it is greatly damaged by the above-described foreign matter. Therefore, it is necessary to remove foreign substances as much as possible. This removal was performed by filtering the recovered recovered plastic through a mesh of stainless steel wire mesh.

  In the existing production line, foreign matter is removed with a mesh having a mesh opening of 780 μm, but this causes damage in forming a thin object. Therefore, filtration was performed using three types of meshes of 389 μm, 250 μm, and 200 μm, which are finer than this. Specifically, filtration was performed immediately before melting at 235 ° C. with a mesh of each size using a twin screw extruder and cooling, and performance evaluation was performed on the obtained samples using a capillograph.

  Resin performance was evaluated by melting a sample at 235 ° C. using a capilograph, extruding using a 2 mm diameter die, and pulling a thinly drawn sample and measuring a limit speed at that time. By pulling the molten resin, it is possible to reproduce the state of the bag molding, which is an index for measuring the molding performance of the bag.

  As a result, it is understood that the opening of the filter and the elongation at break have a good correlation, and that the finer the filter, the higher the molding performance. However, if the eyes are fine, the filter is clogged so quickly that it takes time to clean the filter and the production efficiency falls. In the experiment, a 200 μm filter is not practical because the cleaning time and the resin flow time are almost the same. From FIG. 8, it is considered that the opening is 400 to 250 μm in practice. It is good to decide in this range in consideration of the film thickness of the thin film to be manufactured.

  The thin article forming process will be described with reference to FIG.

FIG. 9 is a configuration explanatory view schematically showing a manufacturing apparatus for forming a plastic film molding material manufactured from used waste plastic according to an embodiment of the present invention into a film.
This apparatus is an extruder called an inflation molding machine, and melts from the barrel 21, the screw 22, the drive motor 23 that drives the screw 22, the material supply feeder 24 provided on the upper surface of the barrel 21, and the end of the barrel 21. An inflation molding die 25 for discharging the resin, an inflation tube 26 for thinly stretching the resin into a bag shape, a film 27 which is a thin product to be manufactured, and a film winder 28 for winding the film 27 The material supply feeder 24 of the molding machine is charged with molding pellets 29 formed from waste plastic and a coloring master batch 30 for coloring the film if necessary, and the temperature of the barrel 21 is set to 180 ° C. to 210 ° C. Inflation molding die 25 at 200 ° C to 210 ° C It is good when the film 27 is formed by setting.

  The film or sheet formed in this step can be an extremely thin single layer having a thickness of 100 to 30 μm.

   Experiments were conducted to see how much performance improvement could be achieved with polymer blends. The recovered waste plastic was blended with commercially available virgin LLDPE (linear polyethylene) or re-pelletized recycled LLDPE recovered as industrial waste.

The recovered plastic waste and recycled LLDPE were mixed at a mixing ratio of 50:50, 60:40, and 70:30 into a twin screw extruder, filtered through a 380 μm filter, and re-pelletized.
The pellets were evaluated for resin performance by dissolving the resin at 235 ° C. using a capilograph and extruding the pellet using a 2 mm diameter die, and measuring the limit speed at that time by pulling out the resin.

  FIG. 10 shows the results obtained for the sample blended with the waste plastic from which the recycled LLDPE was recovered. It can be seen that the blending ratio of the regenerated LLDPE and the elongation at break have a good correlation, and that a large amount of the regenerated LLDPE is blended improves the molding performance of the regenerated pellets.

  Subsequently, an actual machine test was performed using the above-described recycled pellets to produce a thin film sample. Each mesh for recovered plastic containing 30%, 40% and 50% LLDPE (commercially available) and recovered plastic containing 30%, 40% and 50% LLDPE (recycled) recovered as industrial waste The bag formation after the filter filtration was examined. Although the actual working time of the trial production was 20 hours in total, it was found that a product in which 50%, 40%, and 30% of LLDPE were blended in a steady operation state could be continuously produced regardless of blending of commercial products and recycled products.

  FIG. 11 shows an example of the mechanical strength of the manufactured bag. 100% LLDPE (commercial product) from the left side, waste plastic and LLDPE (commercial product) 50:50, waste plastic and LLDPE (commercial product) 60:40, waste plastic and LLDPE (commercial product) 70:30, waste plastic and LLDPE (Recycled product) 80:20, waste plastic and compatibilizer 95: 5 are arranged in this order. From now on, either LLDPE (commercially available) or LLDPE (recycled) is used as the modifying resin, both of which sufficiently pass JISZ1702 packaging polyethylene film type A. Furthermore, waste plastic and LLDPE (recycled product) 70:30 and waste plastic and LLDPE (recycled product) 80:20 are 100% recycled, and the film produced also satisfies JIS standards. Finally, a film produced with a 95: 5 blend of waste plastic and compatibilizer meets JIS standards. The compatibilizer used was a styrene / ethylene / butylene / styrene block copolymer. This compatibilizer has high affinity with polyolefin resins and polystyrene, polyamide, polyethylene terephthalate, etc. The agent itself exhibits a high modulus, and the polymer blend has a high tensile strength and modulus. For this reason, a film manufactured from 95% waste plastic can be formed only by containing 5% of a compatibilizer.

  The cost of these recycled plastics is virgin polyethylene (PE) 150 yen / Kg, recycled polyethylene (PE) 80 yen / Kg, and recycled plastic 20 yen / Kg. For plastic / virgin polyethylene (PE) 70:30, the price is 59 yen / kg, and for recovered plastic / recycled polyethylene (PE) 70:30, the price is 38 yen / kg.

  An example in which a molding material is produced by polymer blending using recycled polyethylene (PE) for waste plastic separated and recovered from a container and packaging plastic and a modifying resin will be described.

Blend ratio Waste plastic recovered / Recycled polyethylene (PE) = 70/30
Twin screw extruder Screw diameter 32mm L / D = 32.5 (L is screw length, D is diameter)
Extruder set temperature Barrel: 200 ° C to 245 ° C Die temperature: 240 ° C
Screw rotation speed 60rpm

  The method for recycling waste plastics into thin products according to the present invention can recycle thin plastic products films that have a wide range of use by utilizing waste plastics collected separately from general waste and recycled LLDPE recovered as industrial waste. Establish plastic circulation cycle in all fields.

It is process drawing explaining each process of the recycling method to the thin product of the waste plastic of this invention. It is process drawing explaining the detailed process of the fraction collection process of this invention. It is a block diagram explaining the odor measurement after washing | cleaning of this invention. It is a pie chart explaining distribution of the kind of the container packaging plastic garbage collect | recovered used for this invention. It is a characteristic view which shows the result of having measured the chemical composition of the collect | recovered plastic fluff used for this invention with the gas chromatograph mass spectrometer (GCMS). It is a lineblock diagram showing roughly the twin screw extruder used for the embodiment of the present invention. It is a conceptual diagram which shows the state of the polymer blend of embodiment of this invention. It is a characteristic view which shows the improvement degree of the film formation performance by the filter of embodiment of this invention. It is a block diagram which shows schematically the manufacturing apparatus shape | molded into the film of embodiment of this invention. It is a characteristic view which shows the shaping | molding performance of the reproduction | regeneration pellet mix | blended with the waste plastic which collect | recovered the reproduction | regeneration LLDPE of this invention. It is a characteristic view which shows an example of the mechanical strength of the shape | molded film of this invention. It is a block diagram which shows the flow in Japan until the total discharge of waste plastics and a recycling process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Twin screw extruder 2 Barrel hole 3 Barrel 4 Screw 5 Drive motor 6 1st material fixed quantity feeder 7 2nd material fixed quantity feeder 8 3rd material fixed quantity feeder 9 Stainless steel wire mesh 10 Die 11 Strand 12 Cooling tank 13 Pelledicer 14 Molding Pellet 15 Receptacle 21 Barrel 22 Screw 23 Drive motor 24 Material supply feeder 25 Inflation molding die 26 Inflation tube 27 Film 28 Film winder

Claims (4)

A step of separating and collecting the waste plastic from the container and packaging plastic, which is a general waste, and a step of kneading the waste plastic and the modifying resin to disperse both finely and almost uniformly,
The waste plastic and the reforming resin granules are put into an inflation molding extruder and molded into a thin product,
The waste plastic is mainly composed of polyethylene (PE) and polypropylene (PP) and occupies 70% by weight or more, and the remainder includes a small amount of different plastics such as polystyrene and other small amounts of different materials,
In the step of separating and collecting the waste plastic, the container and packaging plastic is crushed, separated and collected, washed to remove odors generated from food residues,
The container packaging plastic washing and odor removal treatment is performed by washing with ethylenediaminetetraacetic acid or a surfactant at a temperature of 40 ° C. to 60 ° C., followed by dehydration and water washing to reduce odor,
In the granulating step, the modifying resin is selected from the group consisting of virgin polyethylene (PE) or polypropylene (PP), recycled polyethylene recovered from industrial waste (regenerated PE) or recycled polypropylene (regenerated PP). At least one resin,
The amount of the modifying resin is 30% by weight or less,
The waste plastic and the modifying resin are quantitatively introduced into an extruder, a polymer compatibilizer is added together with the modifying resin, and the compatibility between the dissimilar material and the polyolefin polymer is improved, 180 By kneading while melting at ℃ to 250 ℃, polyethylene (PE), polypropylene (PP), the modifying resin, dissimilar plastics and other small amounts of dissimilar materials are dispersed on a micron order and are uniform on a macro scale. A method for recycling waste plastics into thin products, characterized by using materials. The surfactant is at least mainly composed of a nonionic surfactant such as polyoxyethylene alkyl ether or polyalkylphenyl ether, or N-acylamidopropyl-N, N-dimethylammoniobetaine. It is an ionic surfactant, The recycling method to the thin product of waste plastics of Claim 1 characterized by the above-mentioned.   The method for recycling waste plastic to a thin product according to claim 1 or 2, wherein, in the granulating step, undissolved resin and different materials are removed with a filter having a sieve opening of 400 µm to 250 µm.   In the step of forming into a thin film, an inflation molding extruder is used, and regarding the molding conditions, the set temperature of the extruder is set to 180 ° C to 210 ° C, and the set temperature of the inflation die is set to 200 ° C to 210 ° C. Item 4. A method for recycling waste plastic according to any one of Items 1 to 3 into a thin product.

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