JP2003285328A - Method for recycling waste material of thermoplastic resin composition as resources - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient and inexpensive method for recycling a waste material of a thermoplastic resin composition as resources capable of obtaining a molded object, comprising a thermoplastic resin composition having quality and surplus life corresponding to various uses from the waste material of the thermoplastic resin composition by material recycling using the waste material of the thermoplastic resin composition as a main raw material. <P>SOLUTION: The method for recycling the waste material of the thermoplastic resin composition as resources is equipped with a measuring process for measuring the oxidation induction period of the waste material of the thermoplastic resin composition, a determination process for determining the addition amount of an oxidation inhibitor added to the waste material of the thermoplastic resin composition on the basis of the measuring result, an addition process for adding the oxidation inhibitor to the waste material of the thermoplastic resin composition in the determined addition amount to heat and melt the waste material, and a process for molding the heated and melted waste material of the thermoplastic resin composition to obtain the molded object comprising the thermoplastic resin composition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for recycling a waste material of a thermoplastic resin composition. More specifically, the present invention relates to a method for recycling a waste material of a thermoplastic resin composition, which determines a recycling strategy according to the deterioration state of the waste material of the thermoplastic resin composition.

The present invention also relates to a method for producing a thermoplastic resin composition molded body by the above recycling method. Furthermore, the present invention also relates to a thermoplastic resin composition molded body obtained by the above recycling method.

[0003]

2. Description of the Related Art In recent years, as the income level in Japan has improved, an air conditioner (also referred to as an air conditioner in this specification), a television receiver (also referred to as a TV in this specification), a refrigerator, a laundry Appliances such as machines, information equipment such as personal computers and word processors, office equipment such as printers and fax machines,
Various other types of furniture, stationery, toys, and the like have become available for general households at a high penetration rate, and convenience in home life is dramatically improving.

On the other hand, as a result, the amount of discarded products such as these home electric appliances tends to increase year by year. Here, conventionally, the waste materials of products such as these home electric appliances are often recycled through an iron scrap collection route.

However, in recent years, the constituent materials of members of various products such as home electric appliances have changed, the number of members made of metal such as iron has decreased, and the proportion of members made of plastic composition has increased. It is in. Plastic compositions have a greater degree of freedom in design than metals such as iron, and can be provided with various properties that are difficult to achieve with metals, such as by adjusting the components and using additives.
This is because it has many advantages such as being lightweight and highly durable.

[0006] In the waste materials of various products such as home electric appliances in recent years, the material composition of various constituent members is complicated, and the ratio of members made of valuable metals such as iron and copper is small, so However, the proportion of members made of a plastic composition, which is low and requires a great deal of labor and cost in the conventional processing method, is profitable even if such waste materials are recycled as resources in the conventional iron scrap recovery route. It is becoming difficult to deal with it because it cannot be obtained.

[0007] Many of the members made of these plastic compositions are synthesized by using reserve fossil fuels such as crude oil as a basic raw material. From the viewpoint of effective utilization of resources, members made of these plastic compositions are provided. In recent years, it has been strongly demanded to promote the recycling of recycled products.

[0008] In addition, carbon dioxide and sulfur oxides are released from the combustion of reserve fossil fuels such as crude oil, global warming is caused, environmental damage such as acid rain is caused, and dioxin is produced by incineration of a plastic composition containing a chlorine compound.
From the viewpoint of suppressing the environmental pollution such as scattering, and the problem of the shortage of the waste landfill processing site due to the increase of the waste material containing the bulky plastic composition, the waste material of the product provided with the member made of these plastic compositions Recycling is becoming an important and urgent issue.

In the present specification, a member made of a plastic composition is also referred to as a plastic member. Further, in this specification, a product including a plastic member is also referred to as a plastic product. further,
In the present specification, waste materials of plastic products are also referred to as plastic waste materials.

Under the above circumstances, the Home Appliance Recycling Law came into effect in April 2001. Here, according to the Home Appliance Recycling Law, as of January 2002, it is obligatory to recycle four items of home appliances, such as air conditioners, TVs, refrigerators, and washing machines. % Or more, TV 55
% Or more, refrigerator 50% or more, washing machine 50% or more are set as legal standard values.

[0011] After the enforcement of the Home Appliance Recycling Law, the collection of plastic waste materials is progressing. As a method of recycling the plastic waste materials thus collected, the plastic waste materials are used as fuel. The so-called thermal recycling method has been widely used. However, according to such a method, although it is possible to recycle the plastic waste material by thermal recycling, there is a problem such as the generation of carbon dioxide gas due to combustion, so that it is a method that sufficiently meets social demands. I can't say.

[0012] Therefore, from the plastic waste material thus recovered, the plastic member is separated for each system of the plastic composition by a method such as manual disassembly,
There has been proposed a method for recycling plastic waste materials by using these plastic members again by processing them into product members or raw materials thereof. Such a recycling method is described as material recycling, in contrast to the above-mentioned thermal recycling.

Among the plastic members separated according to the system of the plastic composition as described above, a member made of the thermoplastic resin composition (also referred to as a waste material of the thermoplastic resin composition in the present specification) is It is possible to recycle materials relatively easily by heating, melting, and molding again.

Therefore, at present, in order to increase the material recycling ratio of plastic waste materials, research and development of a recycling method by material recycling of thermoplastic resin composition waste materials are being carried out with great efforts in various fields. There is.

[0015]

However, the waste material of the thermoplastic resin composition, especially the waste material of the thermoplastic resin composition used for home electric appliances and office equipment is often used for a long time in a severe environment. Therefore, the quality has already deteriorated when it was scrapped, and not only the appearance quality such as discoloration or discoloration but also the physical properties such as strength and flexibility have deteriorated, resulting in poor durability. Often

Therefore, the waste material of the thermoplastic resin composition is often used not as a substitute for the virgin material of the thermoplastic resin composition used for the plastic member having high required characteristics but as a raw material for the plastic member having low required characteristics. .

At present, such a cascade recycling is the mainstream as the material recycling of the waste material of the thermoplastic resin composition. Therefore, there is a problem in that the applications of the thermoplastic resin composition molded body recycled from the waste material of the thermoplastic resin composition are limited.

Here, in the present specification, the virgin material means an unused resin composition. Further, in the present specification, it is preferable to use a plastic waste material having deteriorated quality as a raw material of a plastic member having low required characteristics, not as an alternative application of a virgin material of a thermoplastic resin composition used for a plastic member having high required characteristics. , Cascade recycling.

In order to overcome such problems, it is possible to improve the quality of a thermoplastic resin composition molded body obtained by material recycling from the above-mentioned waste material of the thermoplastic resin composition and use it as a plastic member having high required characteristics. Many research and development efforts are being made to reach this standard.

For example, a method for maintaining quality by mixing a virgin material with a waste material (material recycled material) of a thermoplastic resin composition is disclosed in Japanese Patent Laid-Open No. 2000-159.
Many proposals have been made, including the 900 publication.

However, in such a material recycling method, although the physical properties are improved with the mixing of the virgin material, the same physical properties as those of the virgin material are recovered as long as the thermoplastic resin composition waste material having the deteriorated physical properties is mixed. It is impossible to do. Further, in order to approximate the physical properties of the virgin material, it is often necessary to mix a larger amount of the virgin material than the waste thermoplastic resin composition, and it is hard to say that it corresponds to a resource recycling society. is there.
In addition, even a waste material of a thermoplastic resin composition whose physical properties have not deteriorated has a long life greatly reduced by long-term use, and has a problem in long-term reliability when reused.

On the other hand, in Japanese Patent Laid-Open No. 7-24437,
A recycling system is disclosed in which a recycling policy is determined based on the components of a used product and the degree of deterioration, and the resources are repeatedly recycled.

However, in this recycling system, the degree of deterioration, which is the criterion for determining the policy, is based on the physical properties that can be determined by comparison with the virgin material, and the initial characteristics of the recovered waste material are known. Only valid if. However, the amount of waste materials actually collected is enormous, and it takes a huge amount of time and processing capacity to grasp the initial characteristics of each of these and to compare the characteristics of the waste materials with their initial characteristics. And, in reality, it is difficult to realize such a recycling system,
There is also the problem of cost disadvantages.

Further, since the parts used inside the product to be scrapped are less susceptible to the influence of light and the like than the parts used for the appearance, the apparent deterioration degree is low and the physical property values are significant. In some cases, the degree of deterioration does not appear as a difference. Therefore, in such a recycling system, although the material composition of the waste material can be identified, it is difficult to sort the materials based on the deterioration degree.

As described above, by recycling the waste thermoplastic resin composition recovered from the market using the waste thermoplastic resin composition as a main raw material, it can be used as a plastic member having high required characteristics or a raw material thereof. Efficient and low-cost heat capable of obtaining a thermoplastic resin composition molded product that has quality and has a life as a product equivalent to a virgin material (herein also simply referred to as remaining life) Despite the strong demand for the development of a method for recycling plastic resin composition waste materials, such a method for recycling is not yet known.

Based on the above-mentioned present situation, an object of the present invention is to provide a quality and a remaining life suitable for various uses by recycling a waste material of a thermoplastic resin composition with a waste material of the thermoplastic resin composition as a main raw material. It is an object of the present invention to provide an efficient and low-cost method for recycling a waste material of a thermoplastic resin composition capable of obtaining a molded article of the thermoplastic resin composition.

Another object of the present invention is to provide a thermoplastic resin having a quality and a remaining life suitable for various uses by recycling the waste material of the thermoplastic resin composition from the waste material of the thermoplastic resin composition as a main raw material. It is to provide a method for producing a resin composition molded body.

Still another object of the present invention is to:
It is an object of the present invention to provide a thermoplastic resin composition molded body having quality and a remaining life according to various uses, which is obtained by material recycling using a waste material of a thermoplastic resin composition as a main raw material.

[0029]

[Means for Solving the Problems] To solve the above problems, the present inventors evaluated the remaining life of a waste material of a thermoplastic resin composition, and further formulated a stabilization formulation for the waste material of the thermoplastic resin composition. In order to develop a method for recycling such a waste material of a thermoplastic resin composition, an idea that it is sufficient to extend the remaining life by applying Experiments were conducted on combinations such as stabilization methods to extend the remaining life, and earnest studies were repeated.

After the examination, the present inventors evaluated the remaining life of the thermoplastic resin composition waste material by measuring the oxidation induction period of the thermoplastic resin composition waste material, and stored it in a pre-built database. Based on determining the amount of antioxidant required to extend the assessed remaining life,
Further, based on the determination, a predetermined amount of an antioxidant is added to the thermoplastic resin composition waste material and heated and melted, and a thermoplastic resin composition molded body is obtained from the heat-melted thermoplastic resin composition waste material. I found that I should do it.

Further, the present inventors have made further studies, and based on the database, the method for constructing the database, and the amount of the antioxidant necessary for extending the remaining life of the thermoplastic resin composition-forming waste material based on the database. The present invention has been completed by establishing a method for determining the amount of

That is, the method for recycling a waste material of a thermoplastic resin composition of the present invention comprises a measuring step of measuring the oxidation induction period of the waste material of the thermoplastic resin composition, and the thermoplastic resin composition based on the measurement result. A determining step of determining the addition amount of the antioxidant to be added to the waste material, an adding step of adding the determined addition amount of the antioxidant to the waste material of the thermoplastic resin composition and heating and melting, and the heating and melting Forming the thermoplastic resin composition waste material to obtain a thermoplastic resin composition molded body, and recycling the waste material of the thermoplastic resin composition.

Here, in the measuring step, the oxidation induction period of the waste material of the thermoplastic resin composition is measured by placing the waste material of the thermoplastic resin composition in a nitrogen atmosphere and then maintaining the temperature of the nitrogen atmosphere constant. After the temperature is raised to a predetermined holding temperature at a rate, the nitrogen atmosphere is replaced with an oxygen atmosphere and isothermicly held at the holding temperature, and an oxidation induction period until the exothermic peak of the thermoplastic resin composition waste material appears It is preferable to carry out by measuring.

In the measuring step, the holding temperature is preferably determined according to the classification of the waste thermoplastic resin composition based on the information recorded in the database.

Further, in the determining step, the addition amount of the antioxidant is obtained by classifying and recycling the waste material of the thermoplastic resin composition based on the information recorded in the database. Based on the information recorded in the database, the required amount of the antioxidant required depending on the application of the composition molded body is obtained.
From the measured value obtained in the measuring step, determine the residual amount of the antioxidant remaining during the induction period of the thermoplastic resin composition waste material, and determine by determining the difference between the required amount and the residual amount. Is recommended.

Then, in the addition step, the heating and melting temperature is determined based on the information recorded in the database.
Depending on the classification of the waste material of the thermoplastic resin composition, T to (T + 1) with respect to the melting temperature T ° C. of the waste material of the thermoplastic resin composition.
20) It is preferable that it is determined to be in the range of ° C.

In addition, in the addition step, it is desirable that, in addition to the waste material of the thermoplastic resin composition and the antioxidant, an unused thermoplastic resin composition is further added and melted by heating.

Further, in the molding step, it is recommended that the heat-melted thermoplastic resin composition waste material be molded by extrusion molding. In the molding step, it is preferable that the heat-melted thermoplastic resin composition waste material is molded into a pellet-shaped thermoplastic resin composition raw material.

The thermoplastic resin composition waste material is preferably a resin composition waste material containing a polyolefin resin as a main component. Further, it is recommended that the antioxidant be a phenolic antioxidant.

The waste material of the thermoplastic resin composition is
A resin composition waste material having a polyolefin resin as a main component, wherein the antioxidant is a phenolic antioxidant, in the determining step, the measured value of the oxidation induction period measured in the measuring step. Is a (minutes), the remaining amount is b (% (w / w)), and the required amount is c (% (w / w)).
w)), b = 0.055loga-0.0
It is preferable that b is calculated based on the formula 17 and the amount of the antioxidant added is determined in the range of (c−b−0.05) or more.

Here, the required amount c is the remaining life of the waste thermoplastic resin composition d (hours), and the remaining life required for the molded thermoplastic resin composition obtained by recycling the material e. (Hour), c = 0.066 log (e
It is desirable to be determined based on / d).

Further, the present invention includes a method for producing a thermoplastic resin composition molded article, characterized in that a thermoplastic resin composition molded article is obtained by the method for recycling a waste material of the thermoplastic resin composition of the present invention. . Furthermore, the present invention includes a thermoplastic resin composition molded body obtained by the method for recycling a waste thermoplastic resin composition of the present invention.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail by showing embodiments.

The method for recycling a waste material of a thermoplastic resin composition of the present invention comprises a measuring step for measuring the oxidation induction period of the waste material of the thermoplastic resin composition, and the waste material of the thermoplastic resin composition based on the measurement result. A determining step of determining the addition amount of the antioxidant to be added, an adding step of adding the determined addition amount of the antioxidant to the waste material of the thermoplastic resin composition and heating and melting, and the heating and melting A method for recycling a waste material of a thermoplastic resin composition, comprising a step of molding a waste material of the thermoplastic resin composition to obtain a molded body of the thermoplastic resin composition.

<Evaluation Method of Remaining Life> First, FIG. 1 is a conceptual diagram showing a general tendency of deterioration of characteristics of a molded thermoplastic resin composition. As shown in FIG. 1, a thermoplastic resin composition molded body generally has a tendency that the characteristics thereof are rapidly reduced after a deterioration-inducing period peculiar to the thermoplastic resin composition.

Therefore, the waste material of the thermoplastic resin composition recovered from the market has a short remaining life due to long-term use even when the deterioration of the characteristics cannot be confirmed by a physical property test such as measurement of tensile strength. The thermal stability is often reduced.

In other words, some thermoplastic resin composition waste materials recovered from the market have a shorter remaining life due to heat, light, etc. as compared with the time of manufacture. These thermoplastic resin composition waste materials can be reused as they are for parts made of a low-grade thermoplastic resin composition molded article, but in order to develop more applications, the thermoplastic resin composition is used. By accurately evaluating the remaining life of a waste material, it is possible to perform reforming and improvement according to the remaining life and enable application to parts made of a medium-grade or high-grade thermoplastic resin composition molded body. It is preferable for improving the recycling efficiency.

For example, a waste material of a thermoplastic resin composition is shown in FIG.
If the waste material of the thermoplastic resin composition is recycled as a recycled material when it is recovered from the market at the time indicated by A, the remaining life becomes the length shown in B period, and the heat that requires durability or high functionality is used. It cannot be used as a molded body of a plastic resin composition.

To evaluate the remaining life of the molded product of the thermoplastic resin composition, a thermal oxidation deterioration test is generally carried out in a gear type oven at about 150 ° C. to deteriorate the properties of the molded product, for example, cracks are generated. This is done by measuring the time until However, in this test method, it takes several hundred hours to obtain an evaluation result, and when applied to a recycling method of a thermoplastic resin composition waste material, the productivity of the recycling method must be low. There is a problem that you cannot get it.

Further, as shown in FIG. 1, the deterioration of the properties (for example, the physical properties such as tensile strength) of the waste material of the thermoplastic resin composition at the time of recovery is very small, and the decrease of the remaining life is caused by the specific physical properties. It is difficult to evaluate by measurement.

Here, in the course of completing the present invention, the inventors of the present invention, as described later, show the value of the oxidation induction period of the waste material of the thermoplastic resin composition and the value of the remaining life in the thermal oxidation deterioration test. Have a certain relationship. That is, it was found that the residual life of the waste material of the thermoplastic resin composition can be evaluated by measuring the oxidation induction period of the waste material of the thermoplastic resin composition.

Therefore, in the present invention, the residual life of the thermoplastic resin composition waste material recovered from the market is measured by measuring the oxidation induction period of the thermoplastic resin composition waste material instead of performing the thermal oxidative deterioration test. It was decided to evaluate simply and quickly.

In the present invention, the amount of antioxidant to be added to the waste material of the thermoplastic resin composition is determined based on the measurement result of the oxidation induction period, and the predetermined amount of antioxidant is added. A thermoplastic resin composition molded body having a residual life equivalent to that of the thermoplastic resin composition molded body containing a virgin material as a main raw material is obtained by heating and melting the thermoplastic resin composition waste material And

Therefore, in the method for recycling the waste material of the thermoplastic resin composition of the present invention, the measuring step of measuring the oxidation induction period of the waste material of the thermoplastic resin composition, and the thermoplastic resin composition based on the measurement result. Determining step for determining the addition amount of the antioxidant to be added to the waste material, an addition step of adding the determined addition amount of the antioxidant to the waste material of the thermoplastic resin composition, and heating and melting, and the heating And a molding step of molding a melted thermoplastic resin composition waste material to obtain a thermoplastic resin composition molded body.

JP-A-2000-65771 discloses a method of measuring the degree of deterioration of a polypropylene resin molded product by measuring the oxidation induction period of the polypropylene resin molded product.

However, this publication does not describe that the value of the oxidation induction period of the waste material of the thermoplastic resin composition and the value of the remaining life in the thermal oxidation deterioration test have a constant relationship. Further, this publication describes that the value of the time deteriorated by the aging tank and the value of the oxidation induction period have a constant relationship, but the value of the remaining life in the thermal oxidation deterioration test and the deterioration by the aging tank are described. There is no description that the value of the applied time and the value of the oxidation induction period have a certain relationship.

Therefore, from the description of this publication, it cannot be directly derived that the value of the oxidation induction period of the waste material of the thermoplastic resin composition and the value of the remaining life in the thermal oxidation deterioration test have a constant relationship. Absent.

Further, this publication only describes a method for measuring the degree of deterioration of a polypropylene resin molded product, and does not describe a method for recycling a waste material of a thermoplastic resin composition. Therefore, it can be said that the method of recycling the waste material of the thermoplastic resin composition of the present invention cannot be directly derived from the description of this publication.

<Thermoplastic Resin Composition Waste Material> The thermoplastic resin composition waste material used in the present invention has the same physical properties and residual life as the virgin material by using the method for recycling the thermoplastic resin composition waste material of the present invention. Any conventionally known thermoplastic resin composition waste material can be used as long as it is possible to obtain a thermoplastic resin composition molded article having, for example, polypropylene resin, polyethylene resin, thermoplastic polyester resin. A waste material of a thermoplastic resin composition containing a resin or the like as a main component can be preferably used.

Among these thermoplastic resin composition waste materials, the thermoplastic resin composition waste materials containing a polyolefin resin such as a polyethylene resin or a polypropylene resin as a main component are as shown in Table 1 below. , A thermoplastic resin composition molded article recycled by the method for recycling a waste material of a thermoplastic resin composition of the present invention is a thermoplastic resin composition of another classification in terms of processability, economy, etc. Since it is superior to a thermoplastic resin composition molded body that is recycled from waste material, it is preferably used as a raw material for recycling by material recycling in the method for recycling the waste material of the thermoplastic resin composition of the present invention. be able to.

Further, in the waste material of the thermoplastic resin composition containing a polyolefin resin as a main component, in the method for recycling the waste material of the thermoplastic resin composition of the present invention, characteristics are added by adding various additives such as an antioxidant. Because it is easy to improve
There is also an advantage that a thermoplastic resin composition molded article having a stable remaining life can be obtained with good reproducibility.

[0062]

[Table 1]

The characteristics of the main resin compositions in Table 1 were evaluated according to the following criteria. ◯: Excellent Δ: Neither can be said ×: Inferior <Antioxidant> The antioxidant used in the present invention is a thermoplastic resin composition waste material in the method for recycling the thermoplastic resin composition waste material of the present invention. Any conventionally known antioxidant can be used as long as a thermoplastic resin composition molded body having a residual life equivalent to that of a virgin material can be obtained by adding the antioxidant to the virgin material. Antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants and the like can be preferably used.

Among these antioxidants, the phenolic antioxidants are particularly preferable because they are effective in capturing the chain carrier radicals (RO., RO _2. ) In the autoxidative deterioration reaction. Further, among the phenolic antioxidants, the hindered phenolic antioxidants are particularly preferable from the viewpoint of making the method for recycling the waste material of the thermoplastic resin composition more effective.

<Measurement Step> In the measurement step of the present invention, the measurement of the oxidation induction period of the waste material of the thermoplastic resin composition is not particularly limited, and any method can be used as long as it can accurately measure the oxidation induction period. Can be measured by a measuring method of, but since it is a simple and accurate measuring method, especially the thermoplastic resin composition waste material is installed in a nitrogen atmosphere, then the nitrogen atmosphere temperature at a predetermined rate at a predetermined rate. After the temperature is raised to the holding temperature, the nitrogen atmosphere is replaced with an oxygen atmosphere and isothermic holding is performed at the holding temperature, and the oxidation induction period until the exothermic peak of the waste thermoplastic resin composition appears is measured. It is preferable to carry out. In the present specification, a method for measuring such an oxidation induction period is referred to as OIT (O
xygen Induced Time) method.

That is, in the measuring step of the present invention, when the residual life of the thermoplastic resin composition waste material still remains sufficiently, the residual amount of the antioxidant in the thermoplastic resin composition waste material still remains. Since it is sufficiently large, it has a large antioxidation effect, so that it is difficult to oxidize at a predetermined holding temperature in an oxygen atmosphere, and the time until the exothermic peak appears, that is, the oxidation induction period tends to be long.

In the measuring step of the present invention, when the residual life of the thermoplastic resin composition waste material does not remain so much, the residual amount of the antioxidant in the thermoplastic resin composition waste material decreases. Therefore, since the effect of preventing oxidation is small, it easily oxidizes at a predetermined holding temperature in an oxygen atmosphere, and the time until the exothermic peak appears, that is, the oxidation induction period tends to be short.

Therefore, when the residual life of the thermoplastic resin composition waste material is long, the oxidation induction period tends to be long, and when the residual life of the thermoplastic resin composition waste material is short, the oxidation induction period tends to be short. I can say.

Similarly, when the residual amount of the antioxidant in the waste material of the thermoplastic resin composition is large, the oxidation induction period becomes long, and the residual amount of the antioxidant in the waste material of the thermoplastic resin composition is small. In some cases, it can be said that the oxidation induction period also tends to be shortened.

Further, as shown in FIGS. 3 and 4 in Examples described later, a certain relationship is established between the residual life of the waste material of the thermoplastic resin composition and the oxidation induction period. A certain relationship is established between the residual amount of the antioxidant in the waste resin composition and the oxidation induction period.

Therefore, by measuring the oxidation induction period of the waste material of the thermoplastic resin composition, the residual life of the waste material of the thermoplastic resin composition and the residual amount of the antioxidant in the waste material of the thermoplastic resin composition can be increased. It can be said that you can know it by its reliability.

In the measuring step of the present invention,
The waste material of the thermoplastic resin composition for which the oxidation induction period is measured may remain recovered, but in order to accurately measure the oxidation induction period, it is subjected to treatments such as disassembly, crushing, and washing. It is preferably a powdery material. Alternatively, the recovered waste material of the thermoplastic resin composition may be once heated and melted and extruded into a certain shape to be used as a measurement target.

Here, in the measuring step of the present invention, the predetermined holding temperature is preferably determined according to the classification of the waste thermoplastic resin composition material.

It is preferable that the waste material of the thermoplastic resin composition is classified based on the main thermoplastic resin system contained in the waste material of the thermoplastic resin composition. This is because various characteristics including the oxidation induction period of the waste material of the thermoplastic resin composition change based on the main thermoplastic resin system.

If the predetermined holding temperature is too high,
There is a tendency that the oxidation induction period becomes too short and a significant difference is hard to come out. If this predetermined holding temperature is too low, the oxidation induction period becomes too long and the measurement takes too long. Therefore, it is preferable to determine the predetermined holding temperature so that the oxidation induction period is in the range of 1 to 30 minutes, depending on the classification of the waste thermoplastic resin composition.

Therefore, a database is prepared in advance that defines the predetermined holding temperature according to the classification of the thermoplastic resin composition waste material, and the predetermined holding temperature is referred to by referring to the information recorded in this database. Is preferably determined.

That is, in the measuring step of the present invention, the predetermined holding temperature is preferably determined according to the classification of the waste thermoplastic resin composition based on the information recorded in the database.

The predetermined holding temperature may be manually adjusted by the measurer while referring to the information recorded in the database when measuring the oxidation induction period, but from the viewpoint of productivity, Is recorded this database in the storage device of the electronic computer, by inputting the classification of the above thermoplastic resin composition waste material into the electronic computer by a certain means, the program in the electronic computer is stored in this database It is preferable to automatically adjust this predetermined holding temperature with reference to the recorded information.

<Determination Step> In the determination step of the present invention, the amount of the antioxidant added is based on the measurement result of the oxidation induction period by the above measurement step, and the antioxidant added to the waste material of the thermoplastic resin composition. It is possible to determine the addition amount of the thermoplastic resin composition by any method, but since it is a simple and accurate method, the thermoplastic resin composition is particularly based on the information recorded in the database. Based on the information recorded in the database, determine the required amount of the antioxidant required according to the classification and use of the waste material, and based on the information recorded in the database, measure the oxidation value of the thermoplastic resin composition waste material. It is preferable to determine the residual amount of the antioxidant remaining in the induction period by determining the difference between the required amount and the residual amount.

In this case, it is preferable that the waste material of the thermoplastic resin composition is classified based on the main thermoplastic resin system contained in the waste material of the thermoplastic resin composition.
This is because, based on the main thermoplastic resin system, the content of the antioxidant that should be contained varies depending on the application.

In this case, the required amount of the antioxidant of the waste material of the thermoplastic resin composition is determined by the classification of the waste material of the thermoplastic resin composition and the use of the molded article of the thermoplastic resin composition obtained by recycling. It is preferable that the content of the antioxidant is required according to the remaining life required by the above. That is, the content of the required remaining life is the content obtained by applying the value of the required remaining life to a certain relationship established between the content of the antioxidant in the waste material of the thermoplastic resin composition and the remaining life. It is preferable.

Further, in this case, the residual amount of the antioxidant remaining in the waste material of the thermoplastic resin composition is the measured value of the oxidation induction period obtained in the measuring step. It is preferable to apply it to a certain relationship established between the residual amount of antioxidant and the oxidation induction period.

Then, the difference between the above-mentioned required amount and the remaining amount is obtained, and an amount of antioxidant corresponding to the difference is added to the waste material of the thermoplastic resin composition in the adding step to heat-melt and further heat-melt. By molding the waste material of the thermoplastic resin composition thus prepared, it is possible to obtain a thermoplastic resin composition molded article having a required content of the antioxidant.

As a specific example, the thermoplastic resin composition waste material is a resin composition waste material containing a polyolefin resin as a main component, the antioxidant is a phenolic antioxidant, and the determination in the present invention is made. In the process, the measured value of the oxidation induction period measured in the measuring process is a (min), and the residual amount of the antioxidant in the waste material of the thermoplastic resin composition is b.
(% (W / w)), the required amount of antioxidant is c (% (w / w
w)), b is calculated based on the relational expression: b = 0.055loga-0.017 derived from the graph shown in FIG. 4, and the range is (c−b−0.05) or more. It is preferable to determine the addition amount of the antioxidant with.

The above-mentioned required amount c is the residual life of the waste material of the thermoplastic resin composition d (hours), and the residual life required for the molded thermoplastic resin composition obtained by recycling it is e. (Time), the relational expression derived from the graphs shown in FIGS. 3 and 4 is c = 0.066 log (e /
It is preferably determined based on the equation of d).

By adding an amount of the antioxidant determined based on these relational expressions to the waste material of the thermoplastic resin composition, a molded product of the thermoplastic resin composition having a residual life required depending on the use is added. Can be obtained.

Also, when the waste materials of the thermoplastic resin composition and the antioxidants are different in classification, it is preferable to obtain the above relational expressions in advance. further,
It is preferable to create a database recording those relational expressions.

Then, with reference to the information recorded in such a database, the content (required amount) of the antioxidant required according to the classification and application of the waste material of the thermoplastic resin composition, and the thermoplasticity It is preferable to determine the content (residual amount) of the antioxidant remaining in the resin composition waste material oxidation induction period.

That is, in the determining step of the present invention, the amount of the antioxidant added is determined by classifying and recycling the waste material of the thermoplastic resin composition based on the information recorded in the database. Determine the required amount of antioxidant required according to the intended use of the molded body, further based on the information recorded in the database, from the measured values obtained in the measurement process, the thermoplastic resin composition waste material oxidation induction period It is preferable to determine the residual amount of the remaining antioxidant by determining the residual amount and the difference between the required amount and the residual amount.

The amount of the antioxidant to be added may be determined by the operator by himself referring to the information recorded in the database before adding the antioxidant. From the viewpoint of the property, this database is recorded in the storage device of the electronic computer, and the thermoplastic resin composition molded body obtained by classifying and recycling the waste material of the thermoplastic resin composition by a certain means. By inputting the application and the measured value of the oxidation induction period in the above measurement process to the electronic computer, the program in the electronic computer refers to the information recorded in this database and automatically adds the antioxidant. It is preferable to determine the amount.

<Addition Step> The method for recycling the waste material of the thermoplastic resin composition of the present invention comprises heating the waste material of the thermoplastic resin composition with the addition amount of the antioxidant determined in the above-mentioned determining step and heating the waste material. A melting step is provided.

Here, in the addition step in the present invention, the addition of the antioxidant may be carried out by manually measuring the addition amount of the antioxidant determined by the operator. From the viewpoint of properties, it is preferable that the antioxidant is added by an automatic metering device connected to an electronic computer capable of determining the amount to be added, and further by the automatic adding device.

In addition, in the addition step in the present invention, in addition to the waste material of the thermoplastic resin composition and the antioxidant, an unused thermoplastic resin composition (also referred to as a virgin material in the present specification) You may add and heat-melt.

As described above, by adding an unused thermoplastic resin composition to the waste material of the thermoplastic resin composition used in the present invention, a thermoplastic resin obtained by recycling the waste material of the thermoplastic resin composition is obtained. This is because the quality of the molded product of the composition can be further improved.

Here, the unused thermoplastic resin composition is preferably a thermoplastic resin composition of the same system as the thermoplastic resin composition which is a main component of the waste material of the thermoplastic resin composition.

That is, to give a specific example, when the main component of the waste material of the thermoplastic resin composition is a polyolefin resin composition, a polyolefin resin composition is added as an unused thermoplastic resin composition. Is desirable.

At this time, the virgin thermoplastic resin composition to be added depends on the use and required characteristics of the molded product of the thermoplastic resin composition obtained by recycling the waste material of the thermoplastic resin composition. In addition, it is preferable to select an appropriate type.

Further, the larger the amount of the unused thermoplastic resin composition added, the better the quality of the molded thermoplastic resin composition obtained by recycling the waste thermoplastic resin composition. However, if the amount is too large, it is not preferable in terms of manufacturing cost and recycling rate.

Therefore, the blending amount of the unused thermoplastic resin composition to be added is appropriately determined depending on the required characteristics of the molded product to be recycled and the waste material of the thermoplastic resin composition and the unused thermoplastic resin composition. It is desirable to adjust things.

In addition, in the adding step of the present invention, the thermoplastic resin composition waste material is added to the above-mentioned components,
Further, conventionally known additives such as a heat stabilizer, a light stabilizer, an antistatic agent, a lubricant, a filler, a copper damage inhibitor, an antibacterial agent, and a colorant can be obtained by recycling the waste material of the thermoplastic resin composition. You may add as needed in the range which does not prevent the characteristic of a thermoplastic resin composition molded object. The timing of adding these additives is preferably when the raw materials are put into the extruder described later.

In the adding step in the present invention, it is preferable that the waste material of the thermoplastic resin composition that has been heated and melted is mixed with other components after stirring, so that the composition becomes uniform.

<Molding Step> The method for recycling the waste material of the thermoplastic resin composition of the present invention is to mold the waste material of the thermoplastic resin composition which is heated and melted in the above-mentioned adding step to obtain a molded thermoplastic resin composition. A step of obtaining.

In the present specification, the term "thermoplastic resin composition molded body" means not only a usual product or a thermoplastic resin composition molded body as a component thereof, but also a molded product having a predetermined shape. It also includes a thermoplastic resin composition raw material.

The heat melting in the adding step in the present invention and the extrusion molding in the molding step in the present invention are not particularly limited as long as they are devices capable of performing heat melting and extrusion molding, and any conventionally known device can be used. However, in terms of productivity and quality of the thermoplastic resin composition molded body obtained by recycling the waste material of the thermoplastic resin composition, a single-screw extruder, a twin-screw extruder or a multi-screw extruder or a multi-screw extruder can be used. It is particularly preferable to carry out using any one of the axial extruders.

In the molding step of the present invention, in consideration of versatility, it is preferable to mold the thermoplastic resin composition raw material into a certain shape from the thermoplastic resin composition waste material that has been melted by heating. A thermoplastic resin composition molded body having a certain shape may be directly produced from the waste material of the thermoplastic resin composition.

Further, in the molding step of the present invention, the shape of the thermoplastic resin composition raw material to be obtained is preferably a pellet shape which is a general shape of the resin composition raw material, but is not particularly limited to the pellet shape. Instead, it may be in the form of a sheet, a film, a pipe, or the like, and may be appropriately determined depending on the type of extruder.

In the molding step of the present invention, when the thermoplastic resin composition waste material that has been heated and melted is molded into pellet-shaped thermoplastic resin composition raw materials, pellet-shaped thermoplastic resin composition raw materials are used. In order to produce, in addition to the above-described extrusion molding machine, any cutting machine such as sheet cutting, strand cutting, hot air cutting, and underwater cutting may be used, but when an extrusion molding step is further provided in a subsequent step. The underwater cut is particularly preferable because the raw material of the thermoplastic resin composition can be smoothly supplied and the large amount of treatment can be performed.

<Process Flow> An example of the process flow of the method for recycling a waste thermoplastic resin composition of the present invention will be described with reference to the process chart shown in FIG.

In the process flow shown in FIG. 2, first,
The product provided with the thermoplastic resin composition waste material is recovered from the market, and then the product provided with the thermoplastic resin composition waste material is disassembled by manual disassembly or the like to separate the thermoplastic resin composition waste material. Then, the separated waste material of the thermoplastic resin composition is shredded and crushed into a powdery body, and washed to remove dirt and impurities. Then, the washed powdered material of the thermoplastic resin composition waste material is melted by heating, kneaded, and molded into a constant shape by extrusion molding.

In the waste material of the thermoplastic resin composition thus molded into a certain shape, the oxidation induction period is measured in the measuring step, and the addition amount of the antioxidant is determined in the determining step. Then, in the adding step, a determined amount of the antioxidant is added, heated and melted and kneaded, and in the molding step, it is extruded and molded into a thermoplastic resin composition molded body having a certain shape. The above is an example of the process flow of the method for recycling the waste thermoplastic resin composition of the present invention shown in FIG.

Although FIG. 2 is a diagram showing an example of a process flow of the method for recycling a waste material of a thermoplastic resin composition of the present invention, the method for recycling a waste material of a thermoplastic resin composition of the present invention Is not limited to this process flow.

That is, in the process flow shown in FIG. 2, the oxidation induction period of the thermoplastic resin composition waste material is measured after the thermoplastic resin composition waste material is once heated and melted and extruded into a certain shape. However, the timing of measurement of the oxidation induction period of the thermoplastic resin composition waste material is not particularly limited, in the flow of steps of the recycling method of the thermoplastic resin composition waste material of the present invention, at different timing. You may implement.

For example, the recovered thermoplastic resin composition waste material is not disassembled, shredded, crushed, or washed without temporarily melting the recovered thermoplastic resin composition waste material and extruding the recovered thermoplastic resin composition waste material into a fixed shape. After that, the oxidation induction period may be measured immediately.

The method for recycling the waste material of the thermoplastic resin composition of the present invention does not have to include all the steps shown in FIG. 2, but includes the above-mentioned measurement step, determination step, addition step, and molding step. If so, some steps may be omitted, and steps other than the steps shown in FIG. 2 may be added.

[0115]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

<Example> A used water washing machine, which is a molded product of a resin composition containing polypropylene-polyethylene block copolymer resin, which is a typical crystalline thermoplastic resin, is disassembled from a used washing machine recovered from the market. , The dehydration tank and the upper lid were individually taken out and finely crushed. Then, the finely crushed powder of the waste thermoplastic resin composition was washed to remove stains, and each was uniformly mixed.

Then, the mixed powder of the waste material of the thermoplastic resin composition is heated and melted at a temperature of 230 ° C., kneaded and extruded using a screw type 45 mm biaxial melt kneading extruder, and underwater cut is performed. The powder was cut with an apparatus to individually produce pellet-like powders of thermoplastic resin composition waste materials.

Then, these pellet-shaped waste materials of the thermoplastic resin composition are put into the hopper of a 10-ton extrusion molding machine, and they are respectively heated and melted at a temperature of 230 ° C. and a mold temperature of 40 ° C. under extrusion molding conditions. A test piece for measuring physical properties in conformity with ASTM consisting of the waste material of the thermoplastic resin composition of
The physical properties, the oxidation induction period, and the crack initiation time were individually measured. The measurement results are shown in Table 2.

Here, in the present specification, the AST composed of the waste material of the thermoplastic resin composition obtained from each part is used.
Of the M-compliant test pieces for measuring physical properties, the test piece derived from the water tank is also referred to as “RS”, the test piece derived from the dehydration tank is referred to as “RD”, and the test piece derived from the top lid is also referred to as “RU”. I will.

For comparison, a general-grade virgin material of a resin composition containing a polypropylene-polyethylene block copolymer resin was used and the ASTM was used.
Conformity test piece for measuring physical properties (in the present specification, "V-
(Also referred to as "0") was prepared, and its physical properties, oxidation induction period, and crack generation time were measured. The measurement results are shown in Table 2.

[0121]

[Table 2]

As shown in Table 2, "RS" and "R-
D "," RU "tensile strength, flexural strength, flexural modulus,
Each physical property of Izod impact strength was substantially the same as "V-0".

However, "RS", "RD", "R-"
"U" has a shorter oxidation induction period than "V-0", and the crack generation time is also shorter in a form corresponding to the oxidation induction period. Therefore, in order to recycle these thermoplastic resin composition waste materials, in accordance with the required characteristics of the member made of the thermoplastic resin composition molded body obtained by recycling, these thermoplastic resin composition It can be seen that it is necessary to extend the remaining life of waste materials.

Next, "RS", "RD", "R-"
The oxidation induction period and crack generation time of a test piece made of five thermoplastic resin composition waste materials containing "U" and "V-0" were measured. The measurement result is shown in FIG.

Here, in this specification, the time until the occurrence of cracks is also referred to as "crack occurrence time". In the technical field to which the present invention belongs, the above-mentioned thermal oxidative deterioration test is considered to be one of accelerated tests for investigating the remaining life of these thermoplastic resin composition waste materials. It is a common general knowledge that "time" indicates a value corresponding to the remaining life.

As a result, as can be seen from FIG. 3, in these waste materials of the thermoplastic resin composition, a certain correlation was observed between the oxidation induction period and the remaining life.

Therefore, by measuring the oxidation induction period of the waste material of the thermoplastic resin composition in this manner, the remaining life of the waste material of the thermoplastic resin composition can be easily grasped. therefore,
Thermoplastic resin composition obtained by recycling Resource waste of thermoplastic resin composition for various uses by material recycling by modifying waste material of thermoplastic resin composition according to required characteristics of molded product It becomes possible.

Here, in general, a thermoplastic resin composition such as a polypropylene-polyethylene block copolymer resin composition is added with a phenol-based antioxidant and a phosphorus-based antioxidant and is used as a base polymer. The remaining life of the thermoplastic resin is stabilized. Further, in order to improve the heat resistance grade, a sulfur-based antioxidant having a function of enhancing thermal stability is often added.

These antioxidants are gradually consumed during the use of the molded thermoplastic resin composition, and have the function of stabilizing the base polymer. Therefore, it is considered that the amount of the antioxidant contained in the waste material of the thermoplastic resin composition is considerably smaller than the initially added amount.

In order to confirm this point, "RS", "RD", "RU", "V" prepared in Example 1 were prepared.
The amount of antioxidant contained in each "-0" was measured.
The measurement results are shown in Table 3.

[0131]

[Table 3]

As can be seen from Table 3, the consumption of the phenol-based antioxidant varies depending on the environment in which the waste material of the thermoplastic resin composition is used, and the phosphorus-based antioxidant and the sulfur-based antioxidant are Almost all of it was consumed regardless. Therefore, if you know the composition of the waste thermoplastic resin composition, by measuring the oxidation induction period,
It is possible to easily grasp the remaining amount of the phenolic antioxidant.

Next, in order to clarify the relationship between the residual amount of the phenolic antioxidant and the oxidation induction period, in the mixing step of FIG. 2, a thermoplastic resin composition having the same composition as "RD" was used. Tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4-hydroxyphenyl) propione-, which is a hindered phenolic antioxidant, is added to the waste powder.
G] Methane (Asahi Denka Kogyo KK, ADEKA STAB AO6
0) was added in a predetermined amount to prepare a test piece, and the oxidation induction period was measured. The measurement results are shown in FIG.

As can be seen from FIG. 4, there is a certain correlation between the amount of the phenolic antioxidant added (which is almost equal to the residual amount) and the oxidation induction period. By changing the addition amount, it is possible to improve the oxidation induction period, that is, the remaining life of the waste material of the thermoplastic resin composition.

Then, the amount of the phenolic antioxidant added was varied to modify the powder of the waste material of the thermoplastic resin composition having the same composition as "RD" based on the three kinds of prescriptions to obtain the same composition. The waste powder of the thermoplastic resin composition is recycled as a plurality of types of thermoplastic resin composition molded bodies having different required characteristics, and test specimens for physical property measurement conforming to ASTM are prepared. The physical properties, oxidation induction period, and crack initiation time were measured individually. The measurement results are shown in Table 4.

The addition amount of the phosphorus-based antioxidant in the thermoplastic resin composition is 1 to 1 of the phenol-based antioxidant.
Since it is generally 3 times as much, in this example,
2 of total value of residual amount and addition amount of phenolic antioxidant
It was decided to add a double amount of phosphorus-based antioxidant.

That is, in this experiment, in the formulation 1, 0.07 part by mass of the phenolic antioxidant was added to 100 parts by mass of the powder of the waste thermoplastic resin composition, and 0.1.
2 parts by weight of phosphorus antioxidant was added.

In addition, in this experiment, in the formulation 2, with respect to 100 parts by mass of the powder of the waste thermoplastic resin composition,
0.11 part by weight of phenolic antioxidant, 0.25
Part by weight of phosphorus antioxidant was added.

Then, in this experiment, in the prescription 3,
With respect to 100 parts by mass of the waste powder of the thermoplastic resin composition,
0.11 part by weight of phenolic antioxidant, 0.25
Part by mass of phosphorus-based antioxidant and 0.08 part by mass of sulfur-based antioxidant were added to improve heat resistance.

In the formulations 1 to 3, a phenolic antioxidant (Adeka Stab AO manufactured by Asahi Denka Co., Ltd.) was used.
60) and a phosphorus-based antioxidant (Adeka Stub 2112 manufactured by Asahi Denka Co., Ltd.) and a sulfur-based antioxidant (Yoshinox DMTP manufactured by Yoshitomi Fine Chemical Co., Ltd.) were used.

Further, for comparison, "V-0", "V
−1 ”, the physical properties, the oxidation induction period, and the crack generation time of each test piece were individually measured.

Here, "V-1" is a general-grade polypropylene resin manufactured by a different manufacturer from V-0.

[0143]

[Table 4]

As can be seen from Table 4, the formulations 1 to 3 markedly improve the oxidation induction period and the crack generation time of the waste material of the thermoplastic resin composition.

Therefore, the waste material of the thermoplastic resin composition having the formulation 1 is the thermoplastic resin composition having the formulation 2 as a substitute for the molded thermoplastic resin composition having the same composition as "V-0". The waste material can be recycled as a substitute material for the thermoplastic resin composition molded body having the same composition as "V-1".

The above-mentioned physical properties such as tensile strength are "V-" even if the prescriptions 1 to 3 are applied to the waste material of the thermoplastic resin composition.
It is slightly inferior to that of "0" and "V-1", but if the amount is within this range, modification can be performed by mixing an appropriate amount of a virgin material in addition to the antioxidant.

Thus, by appropriately changing the reforming formulation and adding an appropriate amount of the antioxidant and / or the virgin material, several properties can be obtained from the waste material of the thermoplastic resin composition having a single composition. It is possible to obtain a thermoplastic resin composition molded body having the same by recycling, and it is possible to expand the application of the thermoplastic resin composition molded body obtained by recycling the thermoplastic resin composition waste material. Become.

<Measurement Method> Various physical properties (tensile strength, flexural strength, flexural modulus, Izod impact strength), oxidation induction period, and crack generation time measured in the above examples were measured.
It carried out according to the following measuring method.

(I) Method for Measuring Tensile Strength and Tensile Elastic Modulus Using a test piece for measuring physical properties in accordance with ASTM, JIS K
According to 7113, the tensile strength and the tensile elastic modulus were measured.

(Ii) Method for measuring flexural strength and flexural modulus Using a test piece for measuring physical properties in accordance with ASTM, JIS K
According to 7203, bending strength and bending elastic modulus were measured.

(Iii) Method of measuring Izod impact strength Using a test piece for measuring physical properties according to ASTM, JIS K
According to 7110, Izod impact strength was measured.

(Iv) Method of measuring the oxidation induction period Using a test sample having a shape of φ4 mm and a thickness of 1 mm, a thermal analyzer (TG / D manufactured by Seiko Denshi Kogyo KK) was used.
TA320U). First, the test sample was heated to 210 ° C. in a nitrogen atmosphere, held for 10 minutes, then switched to an air atmosphere, and the time until the test sample started an exothermic reaction was measured as an oxidation induction period.

(V) Method for measuring crack generation time As an accelerated test for evaluating the remaining life, a thermal oxidation deterioration test was conducted by leaving an ASTM-compliant test piece for measuring physical properties in a gear type oven at 140 ° C. The time until a crack was generated was measured. Then, this crack generation time was used for evaluation of the remaining life.

The embodiments and examples disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0155]

From the above results, the method for recycling the waste material of the thermoplastic resin composition of the present invention can be varied from the waste material of the thermoplastic resin composition to the material recycling using the waste material of the thermoplastic resin composition as the main raw material. It can be said to be an efficient and low-cost method of recycling a waste material of a thermoplastic resin composition, which can obtain a molded article of a thermoplastic resin composition having a quality and a remaining life depending on various uses.

Further, the method for producing a thermoplastic resin composition molded article of the present invention, which uses the method for recycling a waste material of a thermoplastic resin composition of the present invention, is a method of producing a thermoplastic resin composition from a waste material of a thermoplastic resin composition. It can be said that this is a method capable of producing a thermoplastic resin composition molded body having quality and remaining life according to various uses by material recycling using waste materials as a main raw material.

Then, the thermoplastic resin composition molded article of the present invention obtained by using the method for recycling the waste material of the thermoplastic resin composition of the present invention is a material recycled from the waste material of the thermoplastic resin composition as a main raw material. It can be said that it is a thermoplastic resin composition molded body obtained by having a quality and a remaining life according to various applications.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a graph showing an example of a general tendency of deterioration of properties of a thermoplastic resin composition molded article.

FIG. 2 is a process chart showing an example of a process flow of a method for recycling a waste thermoplastic resin composition of the present invention.

FIG. 3 is a diagram showing a graph showing an example of a correlation between an oxidation induction period and a crack generation time in an example of the present invention.

FIG. 4 is a diagram showing a graph showing an example of the correlation between the amount of antioxidant added and the oxidation induction period in the example of the present invention.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23:00 C08L 23:00 (72) Inventor Tetsuya Kaduma 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Sharp Corporation Inner F term (reference) 4F201 AA03 AA50 AB06 AR20 BA01 BA02 BC01 BC06 BC12 BC25 BC37 BD05 BK01 BK02 BK27 BK74 BL11 4F301 AA12 BD12 BF15 BF27 BF32 CA10 CA36

Claims (11)

[Claims] 1. A measuring step of measuring an oxidation induction period of a waste material of a thermoplastic resin composition, and a determining step of determining an addition amount of an antioxidant to be added to the waste material of the thermoplastic resin composition based on the measurement result. An addition step of adding the determined amount of the antioxidant to the waste material of the thermoplastic resin composition and heating and melting the waste material, and molding the waste material of the heat-melted thermoplastic resin composition to form a thermoplastic resin composition A method for recycling a waste material of a thermoplastic resin composition, which comprises a molding step for obtaining a molded article. 2. The holding temperature of the waste thermoplastic resin composition when measuring the oxidation induction period in the measuring step is
The method for recycling a waste material of a thermoplastic resin composition according to claim 1, which is determined according to a classification of the waste material of the thermoplastic resin composition based on information recorded in a database. 3. The thermoplastic resin composition obtained by classifying and recycling the waste material of the thermoplastic resin composition based on the information recorded in the database, in the determining step, based on the information recorded in the database. Determine the required amount of the antioxidant required depending on the intended use of the molded article, further based on the information recorded in the database, from the measured value obtained in the measuring step, the thermoplastic resin composition The residual amount of the antioxidant remaining in the waste material is determined, and the difference between the required amount and the residual amount is determined to determine the residual amount of the thermoplastic resin composition waste material according to claim 1 or 2. Recycling method. 4. In the adding step, in addition to the waste material of the thermoplastic resin composition and the antioxidant, an unused thermoplastic resin composition is further added and heated and melted. Item 4. A method for recycling a waste material of a thermoplastic resin composition according to any one of Items 1 to 3. 5. The thermoplastic resin composition waste material that has been heated and melted in the molding step is molded into a pellet-shaped raw material of the thermoplastic resin composition.
5. The method for recycling the waste thermoplastic resin composition according to any one of 1 to 4. 6. The waste material of thermoplastic resin composition according to claim 1, wherein the waste material of thermoplastic resin composition is a waste material of resin composition containing a polyolefin resin as a main component. Resource recycling method. 7. The method for recycling a waste material of a thermoplastic resin composition according to claim 1, wherein the antioxidant is a phenolic antioxidant. 8. The thermoplastic resin composition waste material is a resin composition waste material containing a polyolefin resin as a main component,
The antioxidant is a phenolic antioxidant, and in the determining step, the measured value of the oxidation induction period measured in the measuring step is a (minute), and the remaining amount is b.
(% (W / w)), and when the required amount is c (% (w / w)), b is calculated based on the equation of b = 0.05loga−0.017, and (c−b− The method for recycling a waste material of a thermoplastic resin composition according to any one of claims 1 to 5, wherein the amount of the antioxidant added is determined in the range of 0.05) or more. 9. The required amount c is a residual life of the thermoplastic resin composition waste material d (hour), and a residual life required of a thermoplastic resin composition molded body obtained by recycling the material e.
(Hour), c = 0.066 log (e /
The method for recycling a waste material of a thermoplastic resin composition according to claim 8, which is determined on the basis of the equation d). 10. A thermoplastic resin composition molded article obtained by the method for recycling a waste material of a thermoplastic resin composition according to claim 1. Production method. 11. A thermoplastic resin composition molded body obtained by the method for recycling a waste thermoplastic resin composition according to claim 1.