JP2649419B2 - Separation and recovery method of composite waste - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for separating and recovering one or more materials from a composite waste (scrap, defective product, etc.) to which a plurality of materials are adhered. About.

<Conventional Technology> In recent years, from the viewpoint of resource finiteness, soaring raw material prices or preventing pollution, there is an increasing demand for recycling of waste. Recycling of waste consisting of a single material is easy. However, for a composite material to which a plurality of materials are bonded, it is often impossible to recover and collect each of the constituent materials with good profitability.
Recycling is not done in most cases.

As an example of such composite material waste, polyurethane and PVC (polyvinyl chloride) laminated waste (hereinafter, referred to as waste)
Urethane-adhered PVC waste). This occurs in large quantities in manufacturing plants for automobile interior parts, etc.
Usually incinerated or landfilled. But urethane adhesion
When PVC waste is incinerated, chlorine contained in the PVC becomes hydrogen chloride, which corrodes the incinerator and its ancillary equipment, shortening the life of the equipment and causing pollution problems.

For this reason, some attempts have been made to separate and collect urethane-bound PVC waste. In this method, urethane adhered to PVC is crushed by a cutter mill or the like to separate urethane from PVC, and the crushed aggregate is classified by a multi-stage classifier to separate and collect PVC and urethane.

<Problems to be Solved by the Invention> The above-mentioned method of separating and recovering urethane-adhered PVC waste has the following problems: Milling by a cutter mill is to peel urethane from PVC macroscopically. Microscopically, a cutter cuts urethane-adhered PVC waste into three types: pure urethane pieces, PVC pieces to which some urethane is attached, and pure PVC pieces. Urethane, which is the main cause of the deterioration of physical properties, is unavoidable in the recovered PVC because it mainly generates pieces. Since the urethane and PVC are crushed by the cutter mill in almost the same size, Classification by sieving cannot be performed and classification by specific gravity difference is required.In this case, a simple dry classification method that uses the difference in scattering distance in the air stream will cause Left and right It can not be sufficiently classified urethane and PVC because the operation is very troublesome in wet classification method.

As described above, a material separated and recovered from a composite material to which a plurality of different materials are bonded generally has a problem that physical properties are inferior to a new material due to containing impurities.
On the other hand, there is a problem that it is difficult to separate and recover with high purity at a very low yield and to be profitable for a company. These problems make separation, recovery and recycling of composite waste difficult.

The present invention has been made for the purpose of solving the above-mentioned problems, and the problem to be solved is to improve the constituent material from a composite material to which a plurality of materials are adhered by using a simple means. It is an object of the present invention to provide a method of separating and recovering the compound in a high purity and a high yield.

<Means for Solving the Problems> The method for separating and recovering composite material waste according to the present invention, which can solve the above-described problems, roughly crushes composite material waste to which a plurality of materials having different hardnesses are adhered, and then crushes it. The material is pulverized to a different average particle size for each material by stirring with a high-speed stirrer, and then classified.

In the method of the present invention, the hardness of each waste material must be different from each other, and the greater the difference in hardness, such as urethane-attached PVC, the better the separation and recovery can be achieved. Made of different materials,
The method of the present invention is applicable to most wastes. The “composite material in which a plurality of materials are bonded” means a material in which the materials are not mutually melted or uniformly dispersed, for example, a material in which the materials are stacked or combined. Examples of the constituent material of the composite material include a thermoplastic resin, a thermosetting resin, soft and soft rubber, and the like.

The method of the present invention is, so to speak, a first step of coarsely pulverizing waste,
It comprises a second step of pulverizing with a high-speed stirrer and a third step of classifying the pulverized aggregate. Hereinafter, each step will be described.

The coarse grinding in the first step is performed in order to improve the workability in the second step, because the waste generated from the factory or the like is elongated like trimming waste. Therefore, it is better to make the coarse grinding as fine as possible, but the finer the grinding, the higher the grinding cost and the advantage of recycling is lost. On the other hand, the larger the coarse pulverization, the worse the workability in the next step. Therefore, in the first coarse crushing step, an external size of about 20 mm to
It is preferable to roughly pulverize into a lump of about 50 mm.

The second step is, so to speak, a step of pulverizing waste with a high-speed stirrer. Whereas conventional pulverization with a cutter mill pulverizes each material of the composite material to the same degree, in the present invention, each material has a different average particle size, that is, each material has a particle size distribution separated from each other. And crush.

Conventionally, a stirrer has been used to uniformly mix two or more types of materials, whereas in the present invention, since it is used to separate two or more types of materials, the stirrer has a completely opposite effect. Will work. As an effect thereof, the above-mentioned selective pulverization becomes possible.

The conditions such as the number of revolutions of the high-speed stirrer, the shape of the rotating blades, the stirring time, and the temperature may be selected so that each material of the composite waste to be treated is pulverized with different particle sizes.

In the third step, the pulverized aggregate obtained in the second step is appropriately classified, but it is easy to sift using a difference in particle size, and a sieving machine such as an inclined type, a vibrating type, and a rotary type is used. Is enough. If there is a considerable difference in specific gravity between the materials, separation can be performed by using the specific gravity as in the past.

<Operation> When a composite waste to which materials having different hardnesses are bonded is stirred by a high-speed stirrer, the waste receives shearing force from a high-speed rotating stirring blade. Since the stress on it differs for different hardness materials, only one material is ground or each material is ground to have a discrete particle size distribution. Separating the milled aggregate into several grades of uniform particle size provides an isolated version of each material.

<Example> Trimming debris (approximately 140 x 50 cm frame shape, width of surrounding meat part 10 to 1) generated in the manufacturing process of automotive instrument panel pads (inner layer material: soft urethane foam, skin material: PVC)
5 cm, the same thickness 10-15 mm) was obtained and coarsely pulverized to a size of about 30 mm in outer size. For this pulverization, a general uniaxial cutter mill was used to collect the coarse pulverized materials that passed through a φ30 cutter screen, and the resulting mixture was subjected to a high-speed stirring treatment as follows.

The high-speed stirrer used here is Mitsui Miike Kakoki Co., Ltd.
Mitsui Henschel Mixer FM150J, which has the structure shown in the figure. The capacity of the mixing tank 1 is 150,
A jacket 2 capable of controlling the temperature is provided. The opening and closing of the discharge valve 3 is performed by an air cylinder 4. The upper blade 5 and the lower blade 6 are rotated by a three-phase induction motor 7. Reference numeral 8 in the figure denotes each V pulley around which the belt is stretched.

When the lid 11 to which the air vent 9 and the deflector 10 are attached is opened, a coarsely crushed urethane-adhered PVC waste is put in, the lid 11 is closed, and then the high-speed stirrer is operated. The blade 6 is given an upward rotational force to flow, and receives a strong shearing force by the upper blade 5.
Due to this shearing force, urethane is exfoliated from PVC and pulverized in a very short time. PVC is almost the same size as when coarsely crushed.

In this process, the above high-speed stirrer is operated at 7000 rpm under room temperature and normal pressure.
For 5 minutes. The treated product was then separated with an 8-mesh sieve into powder urethane having a particle size of 1 to 2 mm and sheet-like PVC having an outer dimension of about 30 mm. The PVC thus recovered was about 95% of the theoretical recovery.

The PVC separated and recovered as described above is rolled into a 15
Specimens were made by kneading for minutes and examined for specific gravity, hardness, tensile strength, elongation, and tear strength. The specific gravity is
JIS-K-7112 test method 6.2 Measured by the underwater displacement method, and the hardness was measured by the JIS-K-6031 test method: spring hardness (20 ° C) method. The tensile strength, elongation and tear strength were all measured based on the JIS-K-6301 test method.

The test results obtained are shown in the table below. As a control test, the results of tests performed on PVC separated and recovered by the conventional method, new PVC, and untreated waste are also shown.

From this result, it can be seen that the PVC separated and recovered by the method of the present invention has physical properties more suitable for recycling than the conventional method.

The PVC recovered as described above can be used alone as a PVC sheet, or can be used as a vibration-proof sheet or the like by adding calcium carbonate or the like. The recovered urethane is finely divided and can be widely used as a high value-added product. As a use destination, there are a sun visor base material and a cushion material.

In this embodiment, waste having a two-layer structure is used. However, it is possible to separate and collect materials in the same manner as in the present embodiment or by repeating high-speed stirring and sieving for waste having three or more layers. Will be easily understood from.

<Effects of the Invention> The method for separating and recovering composite waste of the present invention has the following effects.

First, the shearing force is applied to the composite material waste by the rotating blades of the high-speed stirrer, so that each material can be separated almost completely, so that the recovery rate is further improved and can contribute to resource saving.

The almost complete separation also increases the purity of the recovered material. This means that a material that is even closer to a new material in physical properties can be obtained, and the range of reuse can be expanded.

In addition, since each material can be collected as pulverized materials having different particle sizes, the classification method is easy, and even a sieve can be sufficiently classified. Therefore, the cost of separation and collection can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a high-speed stirrer used in one embodiment of the method of the present invention.

Claims (1)

(57) [Claims] The method comprises the steps of: coarsely pulverizing a composite waste to which a plurality of materials having different hardnesses are adhered, and then pulverizing the composite waste to a different average particle size for each material by stirring it with a high-speed stirrer;
A method for separating and recovering composite material waste, characterized by classifying.