JPH0330877A - Method for separating and recovering composite material waste - Google Patents

Abstract

PURPOSE:To separate and recover respective materials at high purity in high yield by grinding the waste of a composite material wherein a plurality of materials different in specific gravity are laminated by a cutter mill wherein the interval between both edges of a fixed blade and a rotary blade is set to a predetermined dimension and further classifying the ground one on the basis of specific gravity difference. CONSTITUTION:The waste of a composite material wherein a plurality of materials different in specific gravity are laminated is ground by a cutter mill wherein the interval between the edges of a fixed blade 1 and a rotary blade 4 is set to a dimension 100-300% the thickness of the layer highest in specific gravity of the composite material. Next, the ground material is classified by respective materials by utilizing specific gravity difference. The waste material is composed of a bonded or combined body of respective materials having some shapes not mutually melted or uniformly dispersed. Each material is almost completely peeled off from each other by setting the distance between the blades for cutting, and the classification separation becomes easy. By this method, a recovery good of a high purity may be obtained at a low recovery cost.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for separating and recovering one or more materials from composite waste (scrap, defective products, etc.) in which a plurality of materials are laminated. Regarding.

<Prior Art> Recently, there has been a strong demand for the recycling of waste from the viewpoints of limited resources, rising prices of raw materials, and prevention of pollution. If waste is made of a single material, it is easy to recycle it. However, in the case of composite materials in which a plurality of materials are laminated, it is often impossible to separate and recover the constituent materials in a profitable manner, and recycling is not carried out in most cases.

An example of such composite material waste is waste made of layers of polyurethane and PVC (polyvinyl chloride) (hereinafter referred to as
(called urethane-adhered PVC waste). A large amount of this is generated in factories that manufacture automobile interior parts, etc., but it is usually disposed of by incineration. However, urethane attached PvC
When waste is incinerated, the chlorine contained in PVC turns into hydrogen chloride, which corrodes the incinerator and its auxiliary equipment, shortening the lifespan of the equipment (not only that, but it also tends to cause pollution).

Therefore, some attempts have been made to separate and recover urethane-adhered PVC waste. The method involves crushing urethane-adhered PVC waste with a cutter mill to peel the urethane from the PVC, and then classifying the crushed aggregate using a multi-stage classification device to separate and recover PVC and urethane.

<Problems to be solved by the invention> The above method for separating and recovering urethane-adhered PVC waste has the following problems: ■Urethane and PVC are separated by pulverization using a conventional cutter mill.
The PvC separated and recovered from the pulverized material by classification is inevitably contaminated with 20 to 30% of urethane, which is the main cause of the deterioration of its physical properties. In order to ensure sufficient quality, a multi-stage classification device is required to classify the pulverized material, and wet classification using water is required in the final process, resulting in large running costs and drying costs, making it difficult to recycle. Cost benefits are lost.

As mentioned above, materials separated and recovered from composite materials made of multiple layers of different materials generally contain impurities and therefore have inferior physical properties compared to new materials.
If you try to separate and collect high-purity products, the yield rate is extremely low, making it difficult for companies to make profits.These problems make it difficult to separate, collect, and recycle composite waste.

The present invention was made for the purpose of solving the above-mentioned problems, and the problem to be solved is to increase the constituent materials of waste composite materials made by laminating a plurality of materials by a simple means. It is an object of the present invention to provide a method for separating and recovering with high purity and high yield.

Means for Solving the Problems〉 The method for separating and recovering composite material waste of the present invention that can solve the above problems is a method for separating and recovering composite material waste in which a plurality of materials having different specific gravities are stacked, using a double blade of a fixed blade and a rotary blade. It is characterized in that it is pulverized with a cutter mill whose tip spacing is 100 to 300% of the thickness of the layer with the highest specific gravity of the composite material, and the resulting mixed pulverized material of each material is classified based on the difference in specific gravity.

In the method of the present invention, the waste materials must have different specific gravity, and the greater the difference in specific gravity, such as urethane-attached PVC, the better the separation and recovery can be performed. Note that a "composite material made of multiple laminated materials" is a material in which the materials are not melted or dispersed uniformly, and are materials that have a certain shape that are adhered or combined. means a material that has been Examples of the constituent materials of the composite material include thermoplastic resins, thermosetting resins, soft and hard rubbers, and the like.

The method of the present invention, so to speak, consists of the following two steps: i) First step: A step in which the waste is pulverized with a cutter mill in which the distance between the fixed blade and the rotary blade is widened.

ii) Second step: A step of classifying the pulverized material obtained in the first step into each material using the difference in specific gravity.

This is a method that has Each step will be explained below.

In the first step, in order to more effectively separate each material of the composite material, a cutter mill is used to simultaneously perform peeling and pulverization.

Normally, a cutter mill can only crush materials, but by adopting a special method of use, contrary to the conventional method, by widening the distance between the fixed and rotating blades of the cutter mill, the cutter mill is able to crush materials. In addition, peeling can also be performed.

It is important that the distance between the fixed blade and the rotating blade be 100 to 300% of the thickness of the layer with the highest specific gravity of the composite material. In a normal cutter mill, the distance between the fixed blade and the rotary blade is adjusted to about 0.1 mm, but if the waste is made of, for example, 270 layers with a thickness of 0.5 mm and a urethane layer with a thickness of 15 mm, Based on the thickness of the PVC layer, the distance between the fixed blade and rotary blade of the cutter mill is 0.5mm.
= Adjust to 1.5mm. Although peeling can be achieved by widening the distance between the fixed blade and the rotary blade by 300% or more, the crushing ability of the cutter mill is significantly reduced and costs increase.

Therefore, the distance between the edges of the fixed blade and the rotary blade should be about 300 layers at most. On the other hand, if it is less than 100%, no peeling effect can be obtained and it is no different from conventional crushing.

Conditions such as the rotational speed of the cutter mill, the rectangular shape, the size of the cutter screen openings, etc. may be selected so that each material can be separated and recovered most efficiently. Generally, the more finely pulverized the material, the better the recovery rate of each material, but the higher the cost, so the size of the pulverized particles should be selected in consideration of the relationship between cost and recovery rate.

For the classification in the second step, any classification device that utilizes a difference in specific gravity can be used, such as a wind classifier, a centrifugal separator, or a flotation device. If the difference in specific gravity of each material in the composite waste is very small, wet classification may be better, but usually dry classification is sufficient as it is easy to operate. In addition, even when dry classification is used, composite material waste made from materials with a large difference in specific gravity, such as urethane-adhered PV
Classification of the pulverized material of C is carried out in one step to obtain necessary and sufficient PVC.
can be recovered. Of course, two-stage or three-stage classification is possible, but it is not necessary.

The reason why the simple classification method described above is sufficient is that almost complete peeling of the composite material is achieved in the first step.

Note that if the constituent materials of the composite material include materials that are very easily pulverized, and the sieve portion is pulverized with a particle size distribution that differs for each material as much as possible, the appropriate sieve portion may be classified by a machine.

<Function> Increasing the distance between the fixed and rotary blades of the cutter mill will reduce the crushing performance of the cutter mill, but will continue to apply shearing force to the waste. In particular, if the distance between the fixed blade and rotary blade of the cutter mill is set to ioo~300% of the thickness of the layer with the highest specific gravity of the composite material, each stacked material layer will have a layer that receives shearing force and a layer that does not. As a result, exfoliation is promoted and the necessary pulverization is ensured. If each material is almost completely peeled off when the waste is crushed in this manner, the subsequent classification operation becomes easy and a recovered product with high purity can be obtained.

<Example> Automotive instrument panel pad (inner layer material: 15 mm thick soft urethane foam, outer layer material: 0.5 mm thick)
Trimming waste generated in the manufacturing process of PVC (mm) is pulverized with a cutter mill as shown in FIG. This cutter mill is a single-shaft crusher for crushing waste plants manufactured by the end-of-year ironworks.This cutter mill has an upper body 2 and a lower body 3 assembled around a rotary blade 1. 3
is equipped with a fixed blade 4, a screen 5, and a screen holder 6. An opening/closing mechanism (not shown) is provided at the upper part of the upper body 2 and the lower part of the lower body 3, respectively, so that waste can be input from the top and crushed materials can be taken out from the bottom.

In this example, this cutter mill is used in the waste crushing process.
The distance between the fixed blade 4 and the rotary blade 1 was increased from the conventional 0.1 mm to 1.0 mm (200% of the thickness of the PVC layer).

A cross-wind type wind classifier as shown in FIG. 2 was used to classify the pulverized material thus obtained. By forcibly exhausting the air that enters through the ventilation holes 7, 7, . Due to the relationship between the two and gravity, there is a difference in the distance traveled and the particles are separated.

We investigated how the pulverized particle size in the method of this example affects the recovery rate of PVC, and compared it with the conventional method in which pulverization is performed with a fixed blade and a rotary blade having a spacing of 0.1 mm. The results are shown in FIG. In both methods, there are similar statements that the smaller the crushed particle size, the better the recovery rate.
It can be seen that the method of this example is clearly superior to the conventional method.

The PVC separated and recovered as described above is processed into 1 roll using a 2-roll machine.
A test piece was prepared by kneading it for 5 minutes, and its specific gravity, hardness,
The tensile strength, elongation, and tear strength were investigated. The specific gravity was measured by JIS-7112 test method 6.2 submersion method, and the hardness was measured by JIS-6031 test method Nispring hardness (20°C). Further, tensile strength, elongation and tear strength were all measured based on JIS-6301 test method.

The test results obtained are shown in the table below. As a control test, the results of tests conducted on PVC separated and recovered by conventional methods, PVC of item i, and untreated waste are also shown.

Upper row: Vertical direction Lower row: Horizontal direction From these results, 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 by adding calcium carbonate or the like. In addition, the recovered urethane was wide (
Can be used as a urethane product. Its usage is as follows:
There are sun visor base materials, cushion materials, etc.

In this embodiment, waste having a two-layer structure was used, but it will be easily understood from the above explanation that materials can be separated and recovered in the same manner even if the waste has three or more layers.

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

First, the distance between the fixed blade and rotary blade of the cutter mill is widened to a specific width, and the waste is pulverized while applying a shearing force suitable for peeling off the composite material, allowing almost complete separation of each material, further increasing the recovery rate. improves.

The nearly complete separation also increases the purity of the recovered material. This means that it is possible to obtain materials that are even closer to new materials in terms of physical properties, and the range of reuse can be expanded.

Furthermore, since each material can be recovered as pulverized products with different particle sizes, the classification method is easy, and even a sieve can be used for sufficient classification. Therefore, it is possible to reduce the cost of separation and recovery.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main parts of a cutter mill used in one embodiment of the present invention, Fig. 2 is a schematic diagram showing the basic configuration of a classification device used in one embodiment, and Fig. 3 is an embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the pulverized particle size and the PVC recovery rate in an example in comparison with that in a conventional method. In the diagram: 1... Rotating blade 4... Fixed blade 841 diagram

Claims (1)

[Claims] Composite waste made by laminating multiple materials with different specific gravity,
Grinding is performed using a cutter mill in which the distance between the fixed and rotating blades is set to 100% to 300% of the thickness of the layer with the highest specific gravity of the composite material, and the resulting mixed pulverized material of each material is classified based on the difference in specific gravity. A method for separating and recovering composite material waste, characterized by: