JP2010234812A - Recycling method for plastic waste material, manufacturing method for plastic molding using the same, and plastic molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient recycling method for plastic waste material in which a high-definition plastic molding which has quality and life corresponding to various applications can be obtained by material recycle, and to provide a manufacturing method for a plastic molding using the method, and the plastic molding. <P>SOLUTION: The recycling method for a plastic waste material is for recycling a plastic waste material containing a plastic-based mixture which consists of two or more sorts of plastics, at least includes: a sorting process which sorts out a desired plastic from the plastic waste material by specific gravity separation; and a forming step in which the plastic sorted out in the sorting process is heated and melted, and molded to obtain a plastic molding, wherein the forming step includes: a removal process for eliminating a metal mixed in the sorted plastic; and an addition process in which the type and/or amount of an additive which is added to the sorted plastic is changed responding to the amount of a sieve opening of a filter for eliminating the metal and the additive is added. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for recycling plastic waste. Moreover, this invention relates to the manufacturing method of the plastic molding which obtains a plastic molding using the recycling method of this invention, and the obtained plastic molding.

  In recent years, with the improvement of income levels in Japan, an air conditioner (referred to as “air conditioner” in this specification), a television receiver (referred to as “TV” in this specification), Home appliances such as refrigerators and washing machines, personal computers, information devices such as word processors, office equipment such as printers and fax machines, and various other furniture, stationery, and toys are provided at a high penetration rate in general households. Convenience in home life has been dramatically improved.

  On the other hand, as a result, the amount of disposal of various products including these home appliances also tends to increase year by year. Here, conventionally, the recycling of waste products such as home appliances has often been performed through a scrap recovery route.

  However, in recent years, the constituent materials of members of various products including home appliances have changed, and the number of members made of metal such as iron has decreased and the proportion of members made of plastic tends to increase. Plastics have a greater degree of design freedom than metals such as iron, and can impart various properties that are difficult to achieve with metals by preparing components and using additives, and are lightweight and durable. This is because it has many advantages such as high.

  In the present specification, a member made of plastic is referred to as a “plastic member”. In the present specification, a product provided with a plastic member is referred to as a “plastic product”. Furthermore, in this specification, the waste material (waste) of the plastic product is also referred to as “plastic waste material”.

  The waste of various products including household appliances in recent years has a complicated material composition of various components, and the proportion of components made of valuable metals such as iron and copper is small, and the value is low. The proportion of plastic members that require a lot of labor and cost is high in the conventional processing method, and it is difficult to deal with the conventional iron scrap collection route because it is not profitable even if such waste is recycled. It is becoming a situation.

  Many of these plastic members are synthesized using embedded fossil fuels such as crude oil as a basic raw material, and in recent years, there has been a strong demand for recycling these plastic products from the viewpoint of effective use of resources. Yes.

  In addition, environmental destruction such as global warming and acid rain due to the release of carbon dioxide and sulfur oxides from combustion of buried fossil fuels such as crude oil, environmental pollution such as dioxin generation and scattering by incineration of plastics containing chlorine compounds, From the viewpoint of suppressing the problem of shortage of landfill disposal sites due to the increase in bulky plastic waste, the recycling of these plastic waste materials is becoming an important and urgent issue.

  In response to the above situation, the Home Appliance Recycling Law was enforced in April 2001. Here, according to the Home Appliance Recycling Law, as of January 2002, it is obliged to recycle four items of home appliances such as air conditioners, televisions, refrigerators, and washing machines. Legal reference values are set for% or more, television 55% or more, refrigerator 50% or more, and washing machine 50% or more.

  However, plastic products including these home appliances generally include a plurality of plastic members, and these plastic members are often composite materials made of plastics of different materials because the plastic compositions are often made of different materials. There are many things.

  In the present specification, a member made of a plurality of plastics having different materials or a composite member made of a plastic composition of different materials is called a “mixed plastic member”, and the material contained in the mixed plastic member is called “plastic”. It is called "system mixture". In the present specification, a product including a mixed plastic member is also referred to as a “mixed plastic product”. Furthermore, in this specification, the waste material (waste) of the mixed plastic product is also referred to as “mixed plastic waste material”.

  Here, in order to process the mixed plastic member contained in these mixed plastic waste materials again and use it as a member of various mixed plastic products such as home appliances or as a raw material thereof, these mixed plastic members are made of plastic. It is necessary to process again after separating each system. In this specification, after processing the waste in this way, processing and using the product member or its raw material again is referred to as “material recycling” in contrast to thermal recycling.

  On the other hand, there are many methods for recycling plastic waste materials that have been proposed so far by separating plastic waste containing only a single plastic material by manual dismantling. However, such a method of separating and recycling by manual disassembly has a problem that it takes a lot of labor and cost. Furthermore, there is a problem that such a method cannot cope with mixed plastic waste.

  In addition, as a method for avoiding such a problem, there have been many so-called thermal recycling methods in which a mixed plastic member is separated from a mixed plastic waste material and used as a fuel without being classified according to a plastic system. Proposed.

  In this way, as a method of recycling the mixed plastic waste material by thermal recycling, for example, in Patent Document 1, the mixed plastic member separated from the mixed plastic waste material is subjected to dry distillation by heating in a pyrolysis furnace, and the cracked gas and oil are removed. A method for use as a fuel is disclosed. However, according to this method, it is possible to recycle the mixed plastic waste by thermal recycling, but there are problems such as the generation of carbon dioxide by the fuel. Absent.

  In view of this, many development efforts have been made in various fields regarding a method of separating a mixed plastic member from a mixed plastic waste material and further separating the mixed plastic member for each plastic system.

  For example, a method of separating and recycling a plastic system in a liquid by utilizing a specific gravity difference of a mixed plastic member has been widely used. That is, when the mixed plastic member or the crushed material of the mixed plastic member is put into the liquid, the material having a smaller specific gravity than the liquid is floated and separated by being settled having a larger specific gravity than the liquid. However, in the conventional specific gravity separation method using a liquid, foreign matter is mixed into the collected plastic system, and the foreign matter causes a decrease in physical properties. In addition, there is variation in the mixing of foreign substances, and it has been difficult to control the quality of plastic to be recycled.

  Further, for example, in Patent Document 2, a phenol-based compound and a cyclic phosphite compound are added so that a recycled product can be used for a long period of time.

  For example, Patent Document 3 discloses a method for obtaining a recycled plastic by adding a plastic recycling modifier mainly composed of a low-viscosity polymer during heating and melting.

  However, in the above recycling method, it is not considered to determine appropriate additives and addition amounts with respect to variations in the composition and / or amount of foreign substances contained in the recycled plastic. In other words, the composition, amount and particle size of the foreign material are controlled so as to satisfy the required properties of the plastic, such as physical properties, appearance, and long-term reliability. A consistent method of determining

  In addition, when recycling plastic waste taken from collected products, the composition of the collected products depends on the characteristics of the collected products, changes in consumer preferences, the frequency of use of the product depending on the season, etc. There are variations among lots of collected product groups, and it is very difficult to determine appropriate additives.

JP-A-6-226242 JP-A-6-184350 JP 2001-72796 A

  As described above, material recycling from plastic waste collected from the market has a quality that can be used as a highly demanding plastic member or its raw material, and controls foreign substances contained in plastic to be recycled. Despite the desirability of developing a recycling method that makes it possible to obtain the desired quality even with respect to the products and parts to be recovered and the seasonal variations in the amount recovered, such However, the current recycling method is not yet publicly known.

  Based on the above-mentioned present situation, the object of the present invention is to provide an efficient method for recycling plastic waste, which can obtain a high-quality plastic molded product having quality and longevity according to various uses by material recycling. It is to provide.

  Another object of the present invention is to provide a plastic waste material recycling method capable of flexibly obtaining a desired quality even with respect to variations in products and parts that are collected and recycled. It is in.

  Another object of the present invention is to provide a method for producing a plastic molded body capable of producing a high-quality plastic molded body by material recycling from plastic waste, and an obtained plastic molded body.

  In order to solve the above problems, the present inventors have obtained an idea that the foreign matter contained in the plastic to be recycled should be controlled and the characteristics of the plastic should be appropriately modified with respect to the mixed foreign matter. In order to develop a method for recycling such plastic waste, we repeatedly studied the control method of foreign substances contained in plastics to be recycled, the type and amount of additives for the amount of foreign substances mixed in and the particle size of foreign substances. It was. Here, the foreign substance is a substance other than plastic to be recycled.

  At the end of the study, the relationship between the control of foreign substances contained in the plastic to be recycled and the quality control recipe and / or adjustment recipe and / or control recipe corresponding to the mixed foreign substances under the control is derived. The present invention has been reached. That is, the present invention is as follows.

  The present invention is a method for recycling a plastic waste material containing a plastic-based mixture composed of a plurality of types of plastics, the sorting step of sorting a desired plastic from the plastic waste material by specific gravity separation, and the sorting step At least a molding step in which the plastic selected in step 1 is heated and melted and molded to obtain a plastic molded body. The molding step includes a removal step for removing metal mixed in the selected plastic, and removal of the metal. A method for recycling plastic waste material, comprising an addition step of changing the type and / or amount of the additive added to the selected plastic according to the amount of openings of the filter to be added Also provide.

  Here, the metal mixed in the selected plastic contains at least copper and / or iron, and the additive added to the selected plastic is preferably a metal deactivator and / or an antioxidant.

  Moreover, it is preferable that the opening amount of the filter for removing the metal mixed in the selected plastic is 0.20 mm or more and 0.53 mm or less.

  In the method for recycling plastic waste material according to the present invention, a phenolic antioxidant and a phosphorus antioxidant are used as the additive, and the amount of the phenolic antioxidant added is 0.1 per 100 parts by weight of the plastic mixture. It is preferable that the addition amount of the phosphorus antioxidant is 0.01 part by weight to 5 parts by weight and 0.01 part by weight to 5 parts by weight.

  The plastic waste material recycling method of the present invention uses a metal deactivator as the additive, and the amount of the metal deactivator added is 5 parts by weight or less with respect to 100 parts by weight of the plastic mixture. preferable.

  The plastic system to be recycled in the plastic waste material recycling method of the present invention is preferably a plastic system other than polyolefin plastic, polystyrene plastic, polyolefin, or polystyrene.

  The present invention also provides a method for producing a plastic molded body, which obtains a plastic molded body using the above-described method for recycling plastic waste materials according to the present invention.

  The present invention also provides a plastic molded body obtained by the above-described method for producing a plastic molded body of the present invention. Here, the plastic molded body of the present invention is preferably in the form of pellets, and is preferably used for a product selected from the group consisting of an air conditioner, a television, a refrigerator, and a washing machine.

  The present invention can obtain a high-quality plastic molded body that can be used for various purposes from a plastic mixture composed of a plurality of different specific gravity recovered from the market by material recycling using the mixture as a raw material. In addition, it is possible to provide an efficient recycling method that can reduce plastic waste that is thermally recycled.

  In addition, the present invention can provide a recycling method that can flexibly cope with variations in products and members that are collected and recycled, and can obtain desired physical properties and characteristics.

  Further, the present invention provides a method for producing a plastic molded body capable of obtaining a high-quality plastic molded body applicable to various uses from a plastic-based mixture by material recycling using a plastic-based mixture as a main raw material, and plastic molding. The body can be provided.

It is a flowchart which shows a preferable example of the recycling method of the plastic waste material of this invention in steps. It is a figure which shows the oxidation deterioration characteristic of a recycled material.

Embodiments are shown below and the present invention is described in more detail.
The present invention is a method for recycling plastic waste material including a plastic mixture composed of a plurality of types of plastics, and the amount of foreign matters contained in the plastic mixture to be achieved by control and / or the particle size are controlled. Determining the type and / or amount of additive to be added to the plastic mixture based on the determination in the step, and determining the type and / or amount determined in the step to the plastic mixture In the step of obtaining a plastic molding by adding the additive and heating and melting, control is performed so that the foreign matter contained in the plastic mixture has the determined mixing amount and / or particle size. A method for recycling plastic waste materials, comprising a step. Here, the foreign substance refers to a substance other than plastic to be recycled contained in the plastic-based mixture, and includes rubber, metal, dust, dust and the like having a melting point equal to or higher than the heat melting temperature.

  Further, the present invention is a method for recycling plastic waste material including a plastic mixture composed of a plurality of types of plastics, the separation step of selecting a desired plastic from the plastic waste material by specific gravity separation, At least a molding step in which the plastic selected in the selection step is heated and melted and molded to obtain a plastic molded body, and the molding step includes a removal step for removing metal mixed in the selected plastic, and the metal Recycled plastic waste material, comprising an addition step of changing the type and / or amount of the additive added to the selected plastic according to the amount of openings of the filter for removing It is a conversion method.

  When the amount of openings of the filter becomes larger than a certain value, the amount of foreign matter mixed in, particularly the metal content increases, and the physical properties of the recycled plastic deteriorate. On the contrary, the smaller the opening of the filter, the more clogged the filter and the lower the amount of recycled plastic per filter.

  According to the present invention, the filter is clogged by controlling the amount of opening of the filter for removing, for example, the metal that affects the physical properties of the recycled plastic among the foreign matters mixed even when the specific gravity separation is performed. In addition, a desired amount of recycled plastic can be obtained in the molding process. In addition, the characteristics of the recycled plastic can be improved by changing the type and / or amount of the additive depending on the amount of opening of the filter.

  Therefore, it is possible to obtain a recycled plastic that can be adapted to a durable consumer goods member in both physical properties and long-term reliability and can be used for mass production.

  FIG. 1 is a flowchart showing a preferred example of the plastic waste material recycling method of the present invention step by step. FIG. 1 shows a specific example in the case of material recycling of plastic waste that is a waste of four items of home appliances. The plastic waste material recycling method of the present invention basically obtains a desired plastic molded body from plastic waste material, for example, by the procedure shown in FIG.

  In the example shown in FIG. 1, first, four used home appliances discarded from homes and the like are collected (step 101). Next, the waste of the four items of home appliances is disassembled, and large metal parts such as compressors and heat exchangers, and large plastic molded products such as washing machine water tanks and refrigerator vegetable cases are collected for each part. (Step 102). Next, the remaining members of the four items of household electrical appliances from which large metal parts and the like have been collected are roughly crushed to about 60 mm with a large crusher (step 103).

  Subsequently, from the crushed waste of the four items of home appliances, the metal sorter sorts into crushed metal and plastic crushed material, removes the low bulk specific gravity plastic mixture, iron, copper, aluminum and foam Light weight side plastic mixture including plastic, metal, rubber, fine powder, etc. are removed, and heavy side plastic mixture is selected. After pulverizing the weight side plastic to about 10 mm, the weight side plastic mixture is subjected to specific gravity separation (wet specific gravity separation) using a liquid (specific gravity liquid), and sorted and collected for each plastic system for each specific gravity (step) 104).

  The specific gravity of the liquid used for the wet specific gravity separation is preferably changed according to the plastic system to be sorted and recovered. For example, when selecting and collecting polyolefin-based plastic, the specific gravity of the liquid is preferably 0.92 or more, and more preferably 0.95 or more. The specific gravity is preferably 1.01 or less, and more preferably 1.00 or less. When the specific gravity is less than 0.92, a part of the polyolefin-based plastic tends to settle and the recovery rate decreases. Here, the liquid having a specific gravity of 0.92 or more and 1.01 or less is not particularly limited, but is preferably water.

  Further, for example, when selecting and recovering other types of plastic compositions other than polyolefin and polystyrene, the specific gravity of the liquid is preferably 1.00 or more, and particularly 1.01 or more. Is more preferable. The specific gravity is preferably 1.10 or less, and more preferably 1.08 or less. When this specific gravity is less than 1.00, there is a tendency that polyolefin-based plastics are mixed, and when this specific gravity exceeds 1.10, there is a tendency that polyamide-based, polycarbonate-based, rubber and the like are mixed. Here, the liquid having a specific gravity of 1.10 or less and 1.00 or more is not particularly limited, but is preferably a solution in which NaCl is dissolved in water. Alternatively, a solution in which other organic or inorganic substances are dissolved or a mixed solution thereof may be used.

  Furthermore, when the plastic mixture is selected and collected into three types of plastic compositions, ie, a polyolefin-based plastic composition, a polystyrene-based plastic composition, and other types of plastic compositions, the specific gravity is 0.92 or more and 1 It is preferable to use two kinds of the above liquid of 0.01 or less and the liquid of 1.10 or less and 1.00 or more. At this time, although the order is not particularly limited, a polyolefin-based plastic composition and a polystyrene-based plastic composition, and other series of plastic compositions using the liquid having a specific gravity of 1.00 or more and 1.10 or less. It is desirable to separate the polyolefin plastic composition and the polystyrene plastic composition using the liquid having a specific gravity of 0.92 or more and 1.01 or less. In the recycling method of the present invention, it is preferable to select and collect three types of polyolefin plastic, polystyrene plastic and other plastics.

  Thereafter, the plastics selected and collected in step 104 are washed and dried (step 105), and an additive for adjusting physical properties and characteristics is mixed with the plastic mixture to be recycled (step 106). ).

  However, since the plastics of each system selected and collected in step 104 adhere to hot melt or the like, or metal fastening members are embedded in the members, they are naturally settled by wet specific gravity separation. Fine metals such as copper and iron may be mixed in slightly.

  As a method for removing these slightly contained metals, manual selection can be mentioned. In manual metal sorting, there are problems that the cost of recycled materials increases with the increase in labor costs and the sorting accuracy is poor.

  In addition, as another method, there is a method of removing metal using a metal detector, but in order to remove fine metal, a high metal detection capability is required, and there is a problem that the equipment is costly. Increase the cost of recycled plastics.

  In addition, as another method, there is a method of removing a mixture containing metal using a metal detector. However, in addition to the cost of the equipment, the mixture containing metal is removed when the metal is detected. There is a possibility that the plastic to be collected is mixed in the plastic-based crushed material containing metal, and the amount of collected plastic is reduced.

  The same can be said for foreign matters other than metal. In other words, thorough removal of foreign matters has many problems in terms of cost and time, and the type, amount, size, etc. of these foreign matters are appropriately controlled to obtain a recycled plastic that satisfies the required characteristics for reuse. It is desirable.

  Therefore, it is necessary to determine the type and / or amount of the additive to be added before moving to the step of mixing the additive for adjusting physical properties and characteristics. In the recycling method of the present invention, while performing the operations of steps 101 to 105 described above, the step of determining the amount and / or particle size of foreign matters contained in the plastic mixture to be achieved by the control, And determining the type and / or amount of additive to be added to the plastic mixture.

  In order to recycle plastic having desired physical properties and characteristics, it seems that it is preferable to remove all foreign matters in the plastic-based mixture contained in the plastic waste. However, as described above, it is very difficult to remove all foreign substances in the plastic mixture in terms of labor, environment, recycling system, cost, and the like.

  When foreign matter remains in the plastic-based mixture, the foreign matter remains in the recycled plastic, and the mixing amount and / or particle size of the plastic mixture may vary. It is conceivable to guarantee the quality of the recycled plastic by adding various additives and modifying the plastic.

  Therefore, it is necessary to determine an appropriate additive type and / or amount with respect to the amount of mixed foreign substances. At this time, if the amount of foreign matters mixed in the plastic mixture and / or variation in particle size can be controlled, the quality of the plastic can be ensured by using as few kinds and / or amounts of additives as possible.

  In the recycling method of the present invention, the amount of foreign matter and / or the particle size contained in the plastic mixture to be achieved by the control is determined according to the required characteristics of the product using the recycled plastic. It is preferable to control the quality of the plastic to be recycled by controlling the amount of foreign matters and / or the particle size. Moreover, it is preferable that the amount and / or particle size of foreign matters contained in the plastic mixture to be achieved by the control is determined according to the product composition ratio and / or the plastic composition ratio constituting the plastic waste material.

  In the example shown in FIG. 1, first, a property and / or property modification plan for recycling plastics adjusted to desired properties and properties is formulated (step 201). Here, it is desirable to formulate a plan so that the plastic to be recycled has physical properties and / or characteristics that can be used for four items of home appliances. Items to be considered in the physical property and / or property modification plan should be taken into consideration not only general mechanical properties but also subjective properties such as appearance. It is preferable that the property modification plan is considered so that the same physical properties and characteristics as the recovered products and parts are expressed. Then, in order to satisfy the physical property modification plan formulated in this step, the plastic to be recycled is reformed in the following steps.

  Next, the collected product is investigated (step 202). The survey of recovered products refers to the survey of product composition ratio and / or plastic composition ratio. The collected product is preferably investigated for all the information necessary for configuring the product and / or the plastic composition, such as the material, function, component position information, assembly / disassembly procedure, and the like. However, collecting all of the product information may take a great deal of cost and time. In this case, the information related to the product to be taken out may be simplified.

  In the survey of the collected products, the product composition ratio and / or the plastic composition ratio may be extracted from a database accumulated in consideration of the variation of the collected products. The survey of the collected product may be judged from the type of plastic labeled on the product, or may be estimated from seasonal variations such as variation in the plastic composition ratio and the amount collected. Moreover, you may make it estimate the product and member collect | recovered by experience.

  Next, the amount and / or particle size of foreign matters contained in the plastic mixture to be achieved by control is determined (step 203). Here, the determination may be made based on the plastic composition ratio of the plastic-based mixture contained in the plastic waste material, which is predicted by examining the variation in the collected product and plastic such as the season when the product is collected and the amount collected. In addition, it may be made on the basis of the plastic composition ratio estimated from experience and from variations due to the season in which the product is collected, the amount collected, and the like.

  In general, the product composition ratio of the collected product group varies depending on the frequency of use of the product depending on the season. For example, as shown in Table 1, air conditioners and refrigerators are often collected in summer. Along with such variations, the plastic composition ratio changes, and the amount and / or particle size of foreign matters contained in the plastic mixture also changes.

  For example, when the ratio of a refrigerator increases, the component ratio of the urethane used as a heat insulating material of a refrigerator will increase. After these refrigerators are crushed as waste, when the wet specific gravity sorting is performed in step 104 described above, there is a problem that the specific gravity is settled or rises depending on the amount of harness included in urethane. Arise. As a result, depending on the season, there is a possibility that a large amount of foreign substances such as the harness and the harness contained in the urethane are mixed in the plastic selected and collected for each specific gravity.

  Therefore, appropriate measures such as adding a compatibilizer for urethane and adding a metal deactivator for copper wire contained in the harness are required. It is desirable to determine the mixing amount and / or particle size of the foreign matter to be achieved by control in consideration of the variation due to the season. Specifically, the determination is made based on the reforming plan formulated in step 201 described above and the survey result of the collected product in step 202.

  In the method of recycling plastic waste material according to the present invention, as described later, after adding an additive to a plastic-based mixture, uniformly mixing, heating and melting, and then molding, one of a series of flows to obtain a plastic molded body The amount of foreign matters contained in the plastic mixture and / or the particle size are controlled.

  When controlling the amount and / or particle size of foreign substances contained in the plastic mixture by the amount of openings in the filter, for example, in step 203, the physical property values described in the physical property reforming plan in step 201 are performed in step 202. Determine the opening of the filter from the survey of collected products. At this time, as a guideline for determining the amount of opening of the filter, it is desirable to use data showing a relation between a physical property value and / or a characteristic value prepared in advance in a database or the like and a foreign matter mixing amount and / or a particle size. .

  In the plastic recycling method of the present invention, the type and / or amount of the additive to be added to the plastic mixture is determined based on the amount of foreign matters mixed in the plastic mixture and / or the particle size distribution. It is preferable. This is because there is an advantage that it can be expressed by a mathematical model based on the amount of foreign matters and / or the distribution of particle sizes. For example, it is possible to support the determination of the opening amount so as to guarantee the quality with respect to the 3σ variation of the distribution, which is a model expressing the amount of foreign matter and / or the particle size. In the example shown in FIG. 1, based on the determination in step 203, the amount of foreign matters contained in the plastic after control and / or the distribution of particle sizes are predicted and created (step 204).

  The foreign matter contamination distribution and the particle size distribution predicted in step 204 are the foreign matter contamination amount and particle size distribution included in the plastic to be recycled, which is estimated from step 202. Here, the mixing amount distribution is a distribution expressing the mixing amount of foreign substances assumed to be included in the plastic to be recycled, and the particle size distribution is assumed to be included in the plastic to be recycled. It is a distribution that expresses the particle size of the foreign matter to be produced. Further, the mixing amount distribution may be a distribution expressing the probability that a foreign substance mixing amount exists, and the particle size distribution may express a probability that a foreign particle size exists. The mixing amount distribution and the particle size distribution may be approximated to a probability distribution. The particle size distribution may be approximated by, for example, the Weibull distribution shown in Formula 1).

  In Formula 1), x represents an average particle diameter, β represents a scale parameter, and α represents a shape parameter. Here, the average particle size is a commonly used volume particle size. If the amount of foreign matter contained in the plastic to be recycled is small and the average particle size is small, the range of distribution becomes narrow and α takes a large value. On the other hand, if the mixing amount increases, the range of distribution becomes wider, and α takes a small value. It is preferable that the distribution expressing the mixing amount of the foreign matter to be controlled and / or the probability of existence of the particle size determined in step 203 is approximated so that α is 1 or more in the above formula.

  Here, in place of step 204, for example, a press sheet for each plastic system to be recycled is created in advance from at least step 104 of the recycling method shown in FIG. 1 from plastic waste recovered every predetermined period. Then, the amount of foreign matters and / or the particle size may be accumulated as a database from the press sheet, and the amount of foreign matters and / or the particle size may be predicted with reference to this database.

  Then, the physical property reforming plan established in step 201 is satisfied from the mixing amount distribution and / or particle size distribution predicted in step 204 or a database in which the amount and / or particle size of foreign matters prepared in advance are accumulated. The type of additive and / or the amount of additive added is determined (step 205). At this time, using a database in which the types and / or amounts of additives in step 205 derived from the distribution of the amount of foreign substances contained in the plastic to be recycled and / or the particle size distribution are described, these are used. It is desirable to determine the type and / or additive of the additive. Here, as the contamination amount distribution and / or the particle size distribution, a model expressing the contamination amount of foreign matters other than the contamination amount distribution of foreign matters may be used. Similarly, the particle size of foreign matters other than the particle size distribution of foreign matters is used. Alternatively, a model expressing the above may be used.

  As described above, in the recycling method of the present invention, determination of the amount and / or particle size of foreign substances contained in the plastic mixture to be achieved by the control, and additives to be added to the plastic mixture. Is a database in which information on the relationship between the amount and / or particle size of foreign matter in a plastic mixture and the type and / or amount of additive to be added is stored in advance. It is preferable that it is made by utilizing.

  In this way, the kind and / or amount of additives determined in step 205 is added to the plastic mixture after the washing and drying (step 105) and mixed uniformly (step 106). The additive used in the present invention is preferably at least one selected from metal deactivators, compatibilizers, antioxidants, ultraviolet absorbers, crystallization nucleating agents and fillers. This is because the use of at least one selected from the above-mentioned additives as the additive has the advantage that required properties such as mechanical properties, long-term stability and appearance properties can be satisfied.

  The antioxidant used in the plastic waste recycling method of the present invention is not particularly limited, and for example, at least any selected from salicylic acid derivatives, hydrazide derivatives, oxalic acid amide derivatives, sulfur-containing phosphites, and the like. Can be mentioned. By using a metal deactivator, the metal contained in the plastic mixture can be deactivated, and there is an advantage that long-term reliability can be ensured. Here, since the metal deactivator has little effect of directly capturing radicals and suppressing oxidation, it is preferably used in combination with a phenolic antioxidant.

  The compatibilizer used in the plastic waste recycling method of the present invention is not particularly limited, and examples thereof include SBBS (Styrene-Butadiene-Butylene-Styrene), SBS (Styrene-Butadiene-Styrene), SEBS (Styrene-Ethylene-Butylene), EPR (Ethylene-Propylene Rubber), HSBR (Hydrogenated Styrene-ButyleneCylinder), SEBC (Styrene-Ethylene-Btyrene) ine) and the like. By using a compatibilizing agent, it is possible to impart compatibility to plastics other than the plastic to be recycled, which are included in the plastic system to be recycled. For example, the properties of the plastic can be improved by using an additive that is compatible with polystyrene plastic or urethane contained when the polyolefin plastic is recycled. Among these, it is preferable to use SEBS and / or SBS for reasons such as improved impact resistance.

  The antioxidant used in the plastic waste material recycling method of the present invention is not particularly limited, and is at least selected from, for example, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. Either can be mentioned. Long-term reliability can be improved by using an antioxidant. Among them, it is preferable to use a phenol-based antioxidant and / or a phosphorus-based antioxidant because of excellent heat stability and color tone stability.

  Examples of other additives used in the plastic waste recycling method of the present invention include an ultraviolet absorber, a crystallization nucleating agent, and a filler. These additives are not particularly limited. Examples of the ultraviolet absorber include at least one selected from salicylic acid ester, benzotriazole, hydroxybenzophenone, hindered amine, and the like. Examples of the crystallization nucleating agent include at least one selected from benzylidene sorbitol, chloro-substituted benzylidene sorbitol, methyl-substituted dibenzylidene sorbitol, hydroxy-dialuminum, bis-sodium phosphate, methylene bis-phosphate sodium salt, bis-sorbitol and the like. it can. Examples of the filler include at least one selected from silica, mica, talc, aluminum powder, carbon black, molybdenum disulfide, clay, silica gel, calcium carbonate, silica sand, glass fiber, montmorillonite, iron powder, alumina, and the like. Can do.

  In the recycling method of the present invention, as a preferred example of the type and amount of the additive determined in the above step 205, for example, a phenol-based antioxidant and a phosphorus-based antioxidant are used as additives, and 100 weight of a plastic mixture. Examples are the case where the addition amount of the phenol-based antioxidant is 0.01 to 5 parts by weight and the addition amount of the phosphorus-based antioxidant is 0.01 to 5 parts by weight with respect to parts. By adopting such types and amounts of additives, there is an advantage that long-term stability can be ensured with as few types and amounts of additives as possible, which is advantageous in terms of cost.

  Further, as another preferred example of the type and amount of the additive determined in step 205, for example, a metal deactivator is used as the additive, and the amount of the metal deactivator added relative to 100 parts by weight of the plastic mixture. Is 5 parts by weight or less (preferably 0.01 parts by weight or more). By adopting such kinds and amounts of additives, there is an advantage of preventing oxidation of heavy metals, copper, iron and manganese harmful to stabilization contained in the recycled plastic. In addition, when the mesh opening amount is reduced and the metal can be sufficiently removed, the metal deactivator may not be added.

  In the recycling method of the present invention, the above additives are added and mixed uniformly (step 106), and then the plastic is extruded (step 107). Preferably, during the extrusion, the amount of foreign matter contained in the plastic mixture and / or the particle size is controlled by adjusting the opening of the filter based on the determination in step 203. In this case, for example, extrusion is performed by attaching a filter having an opening amount determined in step 203 to the extruder.

  The opening amount of the filter is preferably 0.075 mm or more and 1 mm or less, and particularly preferably determined from 0.15 mm or more and 0.53 mm or less. When the amount of openings is larger than 1 mm, a lot of foreign matters are mixed in, and there is a tendency that foreign matters contained in the plastic to be recycled cannot be sufficiently controlled, and the amount of openings is less than 0.075 mm. Although there is a sufficient ability to control foreign matter, the foreign matter is immediately clogged in the filter, which may reduce the productivity of plastic to be recycled.

  Thereafter, the plastic selected for each plastic system to be recycled is molded to obtain a pellet-shaped plastic raw material for molding (step 108).

  The method for recycling plastic waste material according to the present invention includes a step of determining the amount and / or particle size of foreign substances contained in a plastic mixture to be achieved by control, and a plastic mixture based on the determination in the step. A step of determining the type and / or amount of an additive to be added, and the plastic mixture is added with the type and / or amount of the additive determined in the above step, heated and melted, and then molded into a plastic molded body 1 and includes a step of controlling the foreign matter contained in the plastic-based mixture so as to have the determined mixing amount and / or particle size, all the steps shown in FIG. 1 are performed. There is no need to prepare. Further, in the plastic waste material recycling method of the present invention, steps not shown in FIG. 1 may be added or deleted as necessary.

  The present invention also provides a method for producing a plastic molded body, which obtains a plastic molded body using the above-described method for recycling plastic waste materials according to the present invention. The flowchart shown in FIG. 1 shows the case where the plastic molding manufacturing method of the present invention is performed following the above-described method of recycling plastic waste materials of the present invention.

  In the example shown in FIG. 1, after the plastic raw material is obtained in step 108, the pelletized plastic raw material for molding is managed for each lot (step 109), and the pelletized plastic raw material is put into an injection molding machine. A plastic molded body is created (step 110). The injection molding machine used at this time is not particularly limited, and examples thereof include a screw inline type injection molding machine and a plunger type injection molding machine.

  The present invention also provides a plastic molded body obtained by the method for producing a plastic molded body of the present invention. The plastic molded body of the present invention is preferably used for a product selected from the group consisting of an air conditioner, a television, a refrigerator and a washing machine.

  Further, in the method for producing a plastic molded body according to the present invention, the plastic mixture after the addition of the additive is directly fed into an injection molding machine without producing a plastic raw material having a shape such as a pellet. May be obtained. In this case, the plastic molded body is preferably in the form of pellets.

  EXAMPLES Hereinafter, although an Example and an experiment example are given and this invention is demonstrated in detail, this invention is not limited to these.

<Example 1>
Four items of home appliances after use (TV, air conditioner, refrigerator, washing machine) were collected (step 101). The four items of home appliances were disassembled, and large metal parts such as compressors and heat exchangers, and large plastic molded products such as washing machine water tanks and refrigerator vegetable cases were collected (step 102). Next, the four home appliances from which large metal parts and large plastic molded products were removed were roughly crushed using a normal crusher so that the particle size was about 60 mm (step 104). Next, after sorting into metal-based crushed material and plastic-based crushed material using a normal eddy current sorter, the plastic-based crushed material is put into a normal sealed wind-powered sorter, and lightweight materials such as polyurethane insulation and polystyrene foam are used. Side plastic mixture, metal, rubber, fines, etc. were removed. From the recovered weight side plastic mixture, a coarse plastic particle having a larger particle size was selectively removed. Next, it was finely crushed to about 15 mm using a normal crusher. Next, the liquid was used to separate the light side plastic and the heavy side plastic by the specific gravity difference (step 104). In this example, water having a specific gravity of 1 was used as the liquid used for the wet specific gravity separation, and a plastic-based mixture, which is a lightweight plastic mixture, mainly composed of a polyolefin-based plastic mixture, was selected and collected. The obtained plastic mixture was washed and dried (step 105).

  In addition, while taking into account the physical properties required for the four components of home appliances, a physical property reform plan was formulated so that the physical properties of the parts molded using plastics to be recycled are equivalent to those of the recovered products. (Step 201). Next, the collected product was investigated (step 202). Here, the collected products are the four items of the home appliance. Next, the aperture of the filter was determined to be 0.3 mm from the physical property modification plan and the investigation of the collected product (step 203). In determining the amount of opening of the filter, a database describing the relationship between the amount of opening of the filter and the amount of contamination and / or the particle size in the product composition ratio of the four home appliances was adopted.

  Next, when the determined filter openings are used in the extrusion process, the amount and particle size of foreign substances contained in the plastic-based mixture that is recycled from the four collected home appliances are estimated and recycled. The amount of contaminants contained in the plastic mixture was expressed as a distribution. Similarly, the average particle size of the foreign substances contained in the plastic to be recycled is expressed as a distribution (step 204). Thereafter, from the mixed amount distribution and particle size distribution created in step 204, the type and amount of additive were determined with reference to the database so as to satisfy the physical property modification plan (step 205).

  Next, the determined type and addition amount (type: phenolic antioxidant, phosphorus antioxidant, metal deactivator, addition amount: phenolic antioxidant = 0.2 parts by weight, phosphorus antioxidant = 0.4 parts by weight, metal deactivator = 1.0 parts by weight) were added to the plastic mixture after washing and drying in Step 105 and mixed uniformly (Step 106). Next, it melt-kneaded at 230 degreeC using the twin-screw melt-kneading extruder with a screw diameter of 45 mm, and the pellet-shaped plastic raw material was extrusion-molded (step 107). Note that the extrusion molding was performed with a filter having an opening of 0.30 mm determined in step 203. Thereafter, the plastic material in the form of pellets was put into a hopper of a 10-ton injection molding machine and molded under injection molding conditions of a molding temperature of 230 ° C. and a mold temperature of 40 ° C. (steps 108 to 110).

<Experimental example 1>
When the product collected in the same procedure as in Example 1 is recycled, the relationship between the amount and particle size of foreign substances contained in the plastic to be recycled and the controllability of the foreign substances is organized in a database. The amount of foreign matter mixed in and the particle size were controlled by heating and melting a pellet-shaped plastic raw material to prepare a 220 mm × 220 mm × 1 mm press sheet and visually observing it with reference to a dust measurement chart. Table 2 shows the relationship between the amount of foreign matter contained in the plastic material in the form of pellets and the size thereof and the opening of the filter.

  Further, a database expressing the relationship between the amount of foreign matter and / or the particle size and the amount of openings as shown in Table 2 was created.

<Experimental example 2>
In order to make it possible for the recycled plastics to have physical properties and characteristics that can be used for the components of four items of household electrical appliances, the relationship between the amount of contamination and thermal oxidative degradation was investigated. Table 3 shows the relationship between the amount of foreign matter mixed in the pellet-shaped plastic raw material prepared from the four items of collected home appliances and the oxidative deterioration characteristics of ASTM-compliant physical property measurement test pieces prepared from the pellet-shaped plastic raw material. .

  As can be seen from Table 3, there is a relationship between the amount of foreign matter mixed in and the oxidation deterioration characteristics, and the amount of foreign matter mixed can be controlled by the amount of openings in the filter. In addition, when the collected products shown in Table 3 are four home appliances, a database expressing the relationship between the amount of foreign matters contained in the plastic to be recycled, the amount of opening of the filter, and the thermal oxidation deterioration was created.

<Experimental example 3>
In order to make it possible for recycled plastics to have characteristics that can be used for the four components of home appliances, referring to Experimental Example 2, the relationship between the amount of opening of the filter and the oxidative degradation characteristics and its modification The quality was investigated. Table 4 shows the relationship between the type and amount of additive for improving the oxidative degradation characteristics.

  With reference to Tables 3 and 4, the relationship between the amount of foreign matter mixed in, the type of additive and the amount added was arranged in a database. It has been pointed out for some time that foreign substances contained in recycled plastics are the cause of deterioration of physical properties of molded articles using recycled plastic raw materials. According to the present invention, the foreign substances are controlled and recycled. The specific relationship of the plastic modification plan was revealed.

<Experimental example 4>
In order to adopt the recycled plastic for one of the parts of the refrigerator, the amount of mesh of the screen mesh and the kind and amount of the additive, and the test piece for measuring physical properties in accordance with ASTM made by using these are used. The physical properties shown in Table 5 were measured. In Table 5, the compatibility was investigated by comparing the required characteristics of the refrigerator parts with the physical properties of the physical property measurement test pieces. Here, the required characteristics of the refrigerator parts are the minimum required characteristic values of the parts, and different from the standard values described in the specifications such as the virgin material, it is necessary to satisfy all the characteristic values. For example, in Table 5, the physical property values obtained by adopting a screen mesh opening amount of 0.50 mm and further adding a phenolic antioxidant 0.1 wt% and a phosphorus antioxidant 0.2 wt% are elongation (%) and It can be seen that the Izod impact value is not satisfied and the required characteristics of the refrigerator parts are not satisfied. It can also be seen that when the screen mesh opening of 0.40 mm is employed and no additive is added, the thermal oxidative degradation characteristics are not satisfied. Here, the local deterioration is deterioration that appears locally after the thermal oxidation deterioration test and is included in the appearance characteristics. The required characteristic “<2” of local deterioration of the refrigerator parts shown in Table 5 indicates that the local deterioration that appeared appears in two or less places. Table 5 shows a part of a database for supporting recycling of plastic waste materials. By displaying in the database the mesh diameter and the types and / or amounts of additives as shown in Table 5 and the physical property values and characteristic values of products made using these, it is easy to screen while referring to the database. The amount of mesh openings and additives can be determined.

  The evaluation of the oxidation deterioration characteristics is carried out by leaving a test piece for measuring physical properties in accordance with ASTM in a 140 ° C. gear-type oven, performing a thermal oxidation deterioration test, and measuring the time until cracks are generated, or locally. This was done by counting the number of deteriorated parts and measuring the crack generation time.

<Experimental example 5>
The polyolefin plastics are separated and recovered from the four collected home appliances according to the flow shown in FIG. 1 and blended with a predetermined compatibilizing agent. A twin screw extruder (Technical Bell Co., Ltd., screw diameter φ25 mm, L / D = 26) was used to prepare recycled pellets at a rotation speed of 155 rpm. In addition, the removal of a foreign material was performed with the screen mesh at the time of extrusion, and the sample was prepared. Thereafter, test pieces were prepared by injection molding, and physical properties such as tensile strength were measured and evaluated. The prepared test piece was subjected to a thermal oxidation deterioration test at 140 ° C. for a predetermined time, and then mechanical properties such as tensile strength were measured and evaluated. Furthermore, the influence on the physical properties and productivity by the opening amount of the screen mesh at the time of extruding the separated and recovered polyolefin-based plastic was examined.

  If attention is paid to the metal contained in the foreign matter, it is advantageous to reduce the mesh opening amount because a large amount of metal can be removed. However, since productivity deteriorates, the openings shown in Table 6 are used in this experiment. The amount was examined. The amount of foreign matter was measured by preparing a press sheet of 220 mm × 220 mm × 1 mm and visually observing the dust measurement chart. In addition, productivity was evaluated based on the amount of waste polyolefin-based plastic that could be extruded before venting up during extrusion. Here, SEBS is not blended. The amount of extrusion increases as the mesh size of the screen mesh increases, and the degree of increase decreases with 0.40 mm as a boundary. In addition, the amount of foreign matter added increased, and the elongation and surface impact characteristics tended to decrease. When the mesh size of the screen mesh was 0.53 mm, the amount of foreign matter was significantly increased and the physical properties were greatly reduced. Therefore, two types of SEBS having different styrene / ethylene / butylene ratios as compatibilizers (Tuftec H1043 / H1062 = 1/0) as pellets for pellets extruded with a screen mesh opening of 0.40 mm. 0.5 [wt%]) was added. The styrene / ethylene / butylene ratio of H1043 was 67/33, and was used for the purpose of compatibilization. H1062 had a styrene / ethylene / butylene ratio of 18/82 and was used to improve impact resistance. The physical properties of the pellets were measured and as shown in Table 7, almost the same physical properties as the virgin material were obtained.

  In addition, when an energy dispersive X-ray analyzer JED-2300F (manufactured by JEOL Ltd.) was used to qualitatively and quantitatively determine the inorganic composition in the resin, the amount of openings increased as shown in Table 8. It was found that a lot of metals such as copper and iron were mixed.

  Metals such as copper and iron may be mixed in the polyolefin-based plastic separated and recovered from the mixed plastic. In particular, there is a concern about copper damage to polypropylene due to copper mixing. In this experiment, a metal deactivator was added in addition to the above two compatibilizers and antioxidants for the extruded product with a screen mesh opening of 0.40 mm, and the effect of improving long-term stability was examined. . FIG. 2 shows the tensile strength as an example of the result. Antioxidants include phenolic antioxidants (tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane) and phosphorus antioxidants (Tris- (2 , 4-di-t-butylphenyl) phosphite), and a metal deactivator was a salicylic acid derivative (3- (N-salicyloyl) amino-1,2,4-triazole). As shown in FIG. 2, the thermal stability was improved by adding 0.2 wt% of a metal deactivator. Moreover, the occurrence of local deterioration could be suppressed. From the above, by combining SEBS, an antioxidant, and a metal deactivator as compatibilizers into the recovered polyolefin plastic, a recycled material having physical properties similar to virgin materials and long-term stability can be obtained. As a result, it can be reused as a component of durable consumer goods.

  It should be considered that the embodiments, examples, and experimental examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims (10)

A method for recycling plastic waste including a plastic mixture composed of a plurality of types of plastics,
A sorting step of sorting the desired plastic from the plastic waste by specific gravity separation;
Including at least a molding step in which the plastic selected in the selection step is heated and melted and molded to obtain a plastic molded body,
The molding step includes a removal step for removing metal mixed in the selected plastic, and a type of additive added to the selected plastic according to the amount of openings of the filter for removing the metal, and A method for recycling plastic waste material, comprising an addition step of adding by changing the amount.   The method according to claim 1, wherein the metal includes at least copper and / or iron, and the additive is a metal deactivator and / or an antioxidant.   The method according to claim 1 or 2, wherein an opening amount of the filter is 0.20 mm or more and 0.53 mm or less.   A phenolic antioxidant and a phosphorus antioxidant are used as the additive, and the addition amount of the phenolic antioxidant is 0.01 parts by weight to 5 parts by weight with respect to 100 parts by weight of the plastic mixture. The method according to any one of claims 1 to 3, wherein the additive is added in an amount of 0.01 to 5 parts by weight.   The metal deactivator is used as the additive, and the addition amount of the metal deactivator is 5 parts by weight or less with respect to 100 parts by weight of the plastic-based mixture. The method described.   The method according to any one of claims 1 to 5, wherein the plastic system to be recycled is a polyolefin plastic, a polystyrene plastic, a polyolefin, or a plastic other than a polystyrene.   The manufacturing method of a plastic molding which obtains a plastic molding using the method in any one of Claims 1-6.   A plastic molded body produced by the method according to claim 7.   The plastic molded body according to claim 8, which is in a pellet form.   The plastic molded body according to claim 8 or 9, which is used for a product selected from the group consisting of an air conditioner, a television, a refrigerator, and a washing machine.

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