JP5998330B2 - Composite material regeneration processing method and regeneration processing apparatus - Google Patents

Description

The present invention relates to a recycling method and a recycling apparatus for a composite material formed by combining natural fibers and a thermoplastic resin, and in particular, a fiber content (composite that can be kneaded and has high strength). The present invention relates to a regeneration processing method and a regeneration processing apparatus for a composite material having a natural fiber content) .

In recent years, industrial products formed by combining natural fibers such as kenaf, hemp, and bamboo with thermoplastic resins have been increasingly used to suppress CO2 emissions. For example, in the automobile industry, a composite material formed by combining kenaf fibers and polypropylene and molded into a desired shape is used as an interior material. In order to complete this composite material as a product, it is necessary to heat and melt a plate-like material, pour it into an arbitrary formwork, mold it, and then trim surrounding unnecessary portions. For this reason, a large amount of unnecessary portions are generated. However, since these are composite materials, it is difficult to separate and regenerate each constituent material, and there is a problem that most of them are incinerated. In addition, since the recycled thermoplastic resin and natural fiber are both low in strength, there is a problem that the finished recycled material is insufficient in strength.
Therefore, in order to solve such problems, in recent years, a technique for regenerating a composite material of natural fibers and a thermoplastic resin has been developed, and an invention has already been disclosed in relation to this.

Patent Document 1 discloses an invention relating to a method for regenerating an outer peripheral material or the like generated during processing of a resin molded product containing natural fibers under the name of “Regeneration method of resin molded product containing natural fibers”.
Hereinafter, the invention disclosed in Patent Document 1 will be described. The invention disclosed in Patent Document 1 includes natural fiber and thermoplastic resin fiber entangled with each other, heated and molded by press molding, a natural fiber-containing resin molded product, the defective molded product, and a peripheral material generated during the molding process. (1) A material to be regenerated such as a resin molded product, a defective molded product, or a peripheral material generated during the molding process is crushed into flakes, and (2) a reclaimed material that has been crushed into flakes. The material is housed in a breathable storage bag formed of a thermoplastic resin similar to the thermoplastic resin fiber, and (3) the material to be recycled stored in the storage bag is stored in the storage bag. (4) After that, it is heated and press-molded.
The method for regenerating a natural fiber-containing resin molded product having such characteristics has the effect that a resin molded product having the same rigidity and strength as the natural fiber-containing resin molded product before regeneration is regenerated. For this reason, the recycled material can be easily recycled at a low cost, and at the same time, it can be recycled repeatedly. Therefore, it is possible to reduce the cost when manufacturing a resin molded product containing natural fibers.

JP 2005-48096 A

  In the invention disclosed in Patent Document 1, since the material to be recycled is stored in the storage bag, the work procedure is somewhat complicated. And since it heats and press-molds in the state accommodated in this accommodation bag, a plate-shaped resin molded product is only reproduced | regenerated. Therefore, further processing is required to manufacture a product having a complicated shape, and it is difficult to say that such a product can be manufactured easily and in a short time. Further, since the material to be recycled is pulverized to a size of 10 mm or less, the fiber length of the natural fiber is also cut to 10 mm or less. Therefore, the strength of the molded product may not be sufficient due to the short fiber length.

  The present invention has been made in response to such a conventional situation, and can be easily formed into a complicated shape as well as a plate shape by a simple process, and can be kneaded with a fiber length and height. An object of the present invention is to provide a regeneration processing method and a regeneration processing apparatus for a composite material having strength.

In order to achieve the above object, in the method for regenerating a composite material according to the first aspect of the present invention, in the method for regenerating a composite material formed by combining natural fibers and the first thermoplastic resin, The fiber is a long fiber having a length of 10 mm or more, the first thermoplastic resin is impregnated between each fiber of the natural fiber, and the composite material has a natural fiber content of 40 to 80 weight. A crushing step of crushing the composite material so that its length is 10 to 50 mm, and a heating and kneading step of adding a second thermoplastic resin to the crushed composite material and kneading while heating A molding step of molding the kneaded composite material, and the crushing step extracts only the composite material having a length of 10 to 50 mm from the cutting step of cutting the composite material and the cut composite material A sorting step, and the molding step is kneaded An extrusion step extruding the composite material from the nozzle, the pelleting step of cutting the extruded composite material to the length of 10~50mm formed into pellets, Bei example and formed into pellets after pelleting process The length of the natural fiber contained in the composite material is longer than 10 mm.
In the composite material regeneration processing method having the above configuration, the natural fibers and the first thermoplastic resin constituting the composite material to be reclaimed are cut by the crushing step. The natural fiber is a long fiber having a length of about 10 mm or more, and the first thermoplastic resin is impregnated between the fibers of the natural fiber and has a function as a binder. For example, polypropylene is used. ing. Moreover, the content rate of the natural fiber in the composite material to be regenerated is about 40 to 80% by weight.
Next, in the heating / kneading step, the second thermoplastic resin is added and kneaded while being heated, whereby the first thermoplastic resin and the second thermoplastic resin are melted, and the natural fibers are evenly mixed therein. To be distributed. At the same time, the first thermoplastic resin and the second thermoplastic resin are sufficiently impregnated between the natural fibers.
Subsequently, the recycled composite material is completed by molding the composite material kneaded in the molding step.
The second thermoplastic resin is a resin that is soluble in the first thermoplastic resin. The moldability of the regenerated composite material is improved by adding the second thermoplastic resin, heating and kneading. In addition, in the kneading step, an adhesive strength improver for improving the adhesive strength between the natural fiber and the first thermoplastic resin and the second thermoplastic resin is added to further improve the strength of the recycled composite material. Also good. For example, maleic anhydride-modified polypropylene (MPP) is used as the adhesive strength improver.

In the crushing step, the composite material is repeatedly cut until the length becomes 10 to 50 mm. This length of 10 to 50 mm is set in order to prevent the strength of the recycled composite material from decreasing. Further, since natural fibers are included in this composite material, the length after cutting depends on the length of cutting the composite material. However, since natural fibers originally have a fixed length but are indefinite shape, the length after cutting is not necessarily included in the range of 10 mm to 50 mm.
Further, by forming the shape process, several composites having substantially the same shape is reproduced in a short time. Note that these composite materials having substantially the same shape are exclusively used as semi-finished products before the final product. In this case, the final product is completed through a further melting step and the like.
And an extrusion process forms the string-like composite material without a cut | interruption and indefinite length. Further, the composite material is cut into a length of 10 to 50 mm, whereby the composite material is formed into a pellet shape as an injection molding raw material. For the injection molding, for example, an injection molding machine is used. The composite material has been cut twice to a length of 10 to 50 mm until this pellet forming step. In connection with this, although the length of the natural fiber contained in a pellet-shaped composite material tends to be shortened more, most fibers do not become a length of 10 mm or less. Moreover, the cooling process which cools a string-like composite material may be provided between an extrusion process and a pellet formation process.

The composite material regeneration processing method according to claim 2 is the composite material regeneration processing method according to claim 1, wherein the second thermoplastic resin is selected from polyolefin, polystyrene, recycled polyolefin, and recycled polystyrene. It is characterized by that .
In the regeneration processing method for a composite material having the above structure, the polyolefin is, for example, polyethylene (PE), polypropylene (PP), ethylene vinyl acetate copolymer (EVA), and the like, and generally not included in the polyolefin. Also included is polystyrene (PS). The recycled polyolefin is recycled PE, PP, EVA, PS or the like. Since these are thermoplastic resins, the second thermoplastic resin is highly compatible with the first thermoplastic resin constituting the composite material, and has an action of being easily melted by heating. In addition, the second thermoplastic resin acts as a binder for the composite material to be recycled, and the moldability is improved as compared with the case where the second thermoplastic resin is not added.

Reproduction processing method of a composite material according to an invention of claim 3, wherein, in the process for regeneration of a composite material according to claim 1 or claim 2, containing natural fibers occupying in the composite material after heating and kneading step The rate is 10 to 50% by weight.
In the composite material regeneration treatment method having the above structure , the natural fiber content in the composite material after the heating and kneading step is 10 to 50% by weight. The composite material having the following fiber content is regenerated.

The method for regenerating a composite material according to claim 4 is the method for regenerating a composite material according to any one of claims 1 to 3, wherein the natural fiber is a plant mainly composed of cellulose. It is characterized by being a natural fiber.
In the method for regenerating a composite material having the above-described configuration, the plant-based natural fiber mainly composed of cellulose refers to, for example, kenaf, hemp, bamboo, cotton, banana leaf, palm skin, and the like. In the present regeneration treatment method, any one of these or a plurality of types may be mixed, thereby having an effect that a composite material containing a desired type of natural fiber is regenerated.

The composite material recycling apparatus according to claim 5 is a composite material processing apparatus formed by combining natural fibers and the first thermoplastic resin, wherein the natural fibers have a length. It is a long fiber of 10 mm or more, the first thermoplastic resin is impregnated between the fibers of the natural fiber, and the composite material has a content rate of 40 to 80% by weight of the natural fiber in the composite material. Cutting means for cutting the material so that its length is 10 to 50 mm, sorting means for extracting only the composite material having a length of 10 to 50 mm from the cut composite material, and the selected composite material the second thermoplastic resin was charged, with a heating and kneading means for kneading while heating the kneaded formed form means you molding a composite material, forming shapes means, an extrusion nozzle for extruding a kneaded composite And the extruded composite material is cut to a length of 10 to 50 mm. Comprising a Potter, a length of the natural fibers contained in the composite material cut by the cutter, characterized in that greater than 10 mm.
In the composite material recycling apparatus having the above-described configuration, the “cutting means” refers to a crusher that continuously shears and crushes using, for example, a rotary blade or a fixed blade, and the “sorting means” refers to the size of the sieve mesh. For example, a screen of 10 to 50 mm. Further, the “heating / kneading means” refers to a continuous kneader or the like that includes a rotatable rotor or the like and can knead the composite material and adjust the heating temperature.
The “extrusion nozzle” forms a string-like composite material having an indefinite length with no breaks, and the diameter of the composite material can be adjusted. The “cutter” is, for example, a pelletizer, and has a structure capable of cutting a composite material having an indefinite length into a desired length. Further, a cooling means for cooling the string-like composite material may be provided between the extrusion nozzle and the cutter .
Incidentally, these "cutting means", "sorting means", "heating and kneading means," "formed shape means" may be a structure which are connected to each other be separate respectively, or either of these Alternatively, a structure in which all are combined together may be used.
In the composite material recycling apparatus having such a configuration, the amount of the second thermoplastic resin charged, the kneading temperature, the injection pressure, and the diameter of the extrusion nozzle with respect to the composite material extracted to a length of 10 to 50 mm By adjusting the above, etc., there is an effect that composite materials including natural fibers and having various shapes, fiber contents , and strengths are regenerated.

According to the method for regenerating a composite material according to claim 1 of the present invention, since it is composed of only three steps of a composite material crushing step, a heating / kneading step, and a molding step, it is easy overall. Yes, it is possible to regenerate the composite material easily and at low cost. Therefore, since it is possible to reuse the composite material that is almost incinerated at present, it is possible to improve the utilization efficiency of resources and to suppress the generation of CO2 due to incineration.
Next, since the regenerated composite material has the natural fibers uniformly dispersed in the melted first thermoplastic resin and second thermoplastic resin, the strength and elastic modulus of the composite material become uniform. . That is, a good quality composite material is regenerated. Furthermore, since the first thermoplastic resin and the second thermoplastic resin are sufficiently impregnated between the natural fibers, the fiber surface is covered with these resins, and fiber damage due to kneading is suppressed.
In addition, since the moldability of the regenerated composite material is improved by charging and kneading the second thermoplastic resin and the adhesive strength improver, kneading and molding after the crushing step are facilitated.

Furthermore, according to the method for regenerating a composite material according to claim 1 of the present invention, since the composite material that has been cut repeatedly until the length becomes 10 to 50 mm is extracted, Each piece of composite material melts in time. Therefore, since it is melt | dissolved uniformly, subsequent kneading | mixing becomes easy, while being able to make the time efficiency of kneading | mixing favorable, the composite material in which the natural fiber was disperse | distributed uniformly is reproducible. Also, since the length of natural fiber after cutting depends on the length of the composite material being cut, the length of the natural fiber can be defined to some extent, so the strength of the recycled composite material can be controlled. Is possible.
In addition, since a plurality of the composite material is reproduced in a short time by forming the shape process, the better the production efficiency of the composite. Furthermore, since these composite materials have substantially the same shape, the heat transfer is uniform in the further melting process, and a semi-finished product in which natural fibers are uniformly dispersed as a whole is completed. Since the semi-finished product is molded again, a final product having a desired shape can be manufactured. In other words, shapes other than the plate shape can be freely manufactured.
Since the pellet-shaped composite material is completed, an arbitrary amount of the composite material can be used for subsequent processing. Therefore, it is possible to manufacture end products having various shapes and sizes. Furthermore, since it is in the form of pellets, strict packing is not required when transporting compared to the final product, and the labor and cost of transport can be reduced.
In addition, since the composite material is cut twice, most of the natural fibers do not have a length of 10 mm or less, so the pellet-like composite material is equivalent to this even when compared with the compression-molded composite material. Has strength.

According to the method for regenerating a composite material according to claim 2 of the present invention, the second thermoplastic resin is polyolefin or the like. Moreover, since a part of the composite material to be regenerated is the first thermoplastic resin, it can be easily melted by heating. Therefore, since the regenerated composite material has thermoplasticity, it is possible to repeat heating and cooling. Therefore, the composite material can be reproduced not only once but also multiple times. In addition, when heating and cooling are repeated, there is a concern about deterioration of the first thermoplastic resin. However, by adjusting the amount and type of the second thermoplastic resin, the disadvantage such as strength reduction due to deterioration can be compensated. Can do.
Among the polyolefins used, polyethylene, polypropylene, and polystyrene are general-purpose resins and are relatively inexpensive, so there is little cost burden and the composite material regeneration processing method according to the present invention is easily introduced. Is possible.

According to the method for regenerating a composite material according to claim 3 of the present invention, since the composite material having a fiber content equal to or lower than that of the composite material before the regeneration treatment is regenerated, the composite material before the regeneration treatment is obtained. It is possible to regenerate a composite material that is comparable to the above.

  According to the method for regenerating a composite material according to claim 4 of the present invention, there are a wide variety of combinations of natural fibers that can be regenerated, and it is possible to regenerate a composite material containing a desired type of natural fibers. .

According to the composite reproduction processing apparatus according to claim 5 of the present invention, the "cutting means" - "formed shape means", since the device usually commonly used is employed, existing equipment Is often easy to use. In addition, since composite materials having various shapes, fiber contents , and strengths are regenerated, it is possible to regenerate composite materials having various characteristics and qualities. Accordingly, it is possible to finely meet various demands in the market.

These are process drawings of the regeneration processing method of the composite material which concerns on an Example. These are the real photographs of the recycled composite material according to Example 1. (A) And (b) is the real photograph of the surface of the reproduction | regeneration composite material which concerns on Example 7, and a back surface, respectively.

A method for recycling a composite material according to an embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 is a process diagram of an example of a method for recycling a composite material according to an embodiment of the present invention.

As shown in FIG. 1, the regeneration processing method of the regenerated composite materials C2 and C3 according to the present embodiment includes a crushing step in step S1, a heating / kneading step in step S2, and a forming step in step S3. Among these, the crushing process of step S1 includes the cutting process of step S1-1 and the sorting process of step S1-2. Further, the molding process of step S3 is either the injection / molding process of step S4 or the compression / molding process of step S5. Among these, the injection / molding process of step S4 includes the extrusion process of step S4-1, The pellet molding process of step S4-2 and the injection molding process of step S4-3 are included. The compression / molding process of step S5 includes the extrusion process of step S5-1 and the compression molding process of step S5-2.
The composite material C1 is formed by impregnating a nonwoven fabric made of natural fibers with a first thermoplastic resin, and is compression-molded into a plate shape. The content rate of the natural fiber in it is about 40 to 80% by weight.
The first thermoplastic resin is, for example, polypropylene, polyethylene or the like, and acts as a binder for the nonwoven fabric. In order to facilitate impregnation of natural fibers, a melt flow index (MFI) having a low melt viscosity of about 50 g / 10 min is used.
Natural fibers are, for example, kenaf, hemp, bamboo, cotton, etc., and are long fibers having a fiber length of 10 mm or more.

  In the crushing step of step S1, the plate-shaped composite material C1 is crushed into small pieces so as to be easily kneaded in the heating and kneading step of step S2.

  In the cutting step of step S1-1, the composite material C1 is cut so that the length is 10 to 50 mm. Specifically, for example, the composite material C1 is put into a crusher that continuously shears and crushes with a rotary blade or a fixed blade and cut. Naturally, natural fibers, which are long fibers included in the composite material C1, are also cut, and the length after the cutting is slightly shorter than the length of the composite material C1. However, most fibers do not have a length of 10 mm or less. Moreover, since natural fiber is a nonwoven fabric and the fibers are arranged at random, the length after cutting is not necessarily included in the range of 10 to 50 mm.

  In the selection step of step S1-2, the small piece of the composite material C1 cut in step S1-1 is extracted by a screen having a sieve mesh size of 10 to 50 mm, and only a small piece having a length of 10 to 50 mm. Are sorted out. The small piece of the composite material C1 longer than 50 mm is returned to the cutting process of step S1-1 and cut again. Moreover, the small piece of the composite material C1 whose length is shorter than 10 mm is not sent to the subsequent steps. In this way, by repeating the cutting and sorting of the input composite material C1, small pieces having a length of 10 to 50 mm are formed and sent to the subsequent steps.

In the heating / kneading step of step S2, the second thermoplastic resin R is put into the selected pieces of the composite material C1, and is kneaded while being heated using, for example, a continuous kneader. The second thermoplastic resin R is a recycled PP, PE, PS, EVA or the like, in addition to PP, PE, PS, EVA, or the like, which is a polyolefin. The dose of the second thermoplastic resin R is determined such that the content of natural fibers in the composite material after kneading is 10 to 50% by weight. Further, the MFI of the second thermoplastic resin R is preferably equal to that of the first thermoplastic resin constituting the composite material C1, but is about 10 to 60 g / 10 min. The heating temperature can be freely adjusted, and is preferably 200 ° C. or lower, specifically 185 to 190 ° C., in order to prevent fiber deterioration. In addition, you may add the adhesive strength improving agent which improves the adhesive strength of a natural fiber and the 1st thermoplastic resin or the 2nd thermoplastic resin R. For example, maleic anhydride-modified polypropylene (MPP) is used as the adhesive strength improver. The amount added is about 3% by weight of the amount of resin contained in the composite material C1.
Then, by heating, the first thermoplastic resin and the second thermoplastic resin R of the composite material C1 are melted and integrated, and natural fibers are evenly dispersed therein by kneading performed simultaneously. That is, the first thermoplastic resin and the second thermoplastic resin R of the composite material C1 are sufficiently impregnated between the natural fibers.

  In the molding process of step S3, the composite material kneaded in the heating / kneading process of step S2 is formed as a semi-finished product or a final product by either the injection / molding process of step S4 or the compression / molding process of step S5, respectively. Is done.

  In the injection / molding process of step S4, the composite material kneaded in the heating / kneading process of step S2 is molded into a pellet shape, and the recycled composite material C2 is manufactured as a semi-finished product.

  In the extrusion process of step S4-1, the kneaded composite material is put into an injection molding machine and extruded from an extrusion nozzle provided in the injection molding machine while maintaining the temperature in the heating / kneading process. As a result, a string-like composite material having no break and an indefinite length is formed. The injection pressure of the extrusion nozzle can be adjusted, and is set to about 1 to 4 MPa, for example. Moreover, the specific aperture is 2-6 mm.

  In the pellet molding process of step S4-2, the string-like composite material formed in the extrusion process of step S4-1 is cut into a certain length using a pelletizer or the like. This fixed length can be arbitrarily adjusted within a range of 10 to 50 mm. In addition, the composite material C1 will be cut | disconnected twice by the cutting process of this step S1-1, and this process. If such cutting is repeated, the length of the natural fiber tends to be shortened. For example, if cutting is performed to a length of 50 mm in the cutting process of step S1-1 and cutting to a length of 10 mm in this process. An increase in the proportion of fibers shorter than 10 mm is prevented. In addition, the cooling process which cools a string-like composite material may be provided between the extrusion process of step S4-1 and the pellet formation process of step S4-2.

  In the injection molding process of step S4-3, the recycled composite material C2 as a semi-finished product is manufactured by putting the pellet-shaped composite material molded in the pellet molding process of step S4-2 into an injection molding machine.

  In the compression / molding step of step S5, the recycled composite material C3 is manufactured as a final product by compression-molding the composite material kneaded in the heating / kneading step of step S2.

  In the extrusion process of step S5-1, the composite material kneaded in the heating / kneading process of step S2 is poured out into a mold having an arbitrary shape.

  In the compression molding step of step S5-2, the composite material poured into the mold is pressed with a compression molding machine and molded into a fixed shape. The applied pressure is about 1 to 10 MPa.

In this embodiment configured as described above, the composite material C1 containing natural fibers is regenerated and composited by a simple process of the crushing process of step S1, the heating / kneading process of step S2, and the molding process of step S3. It can be recycled as materials C2 and C3. Accordingly, it is possible to easily and cost-effectively reuse the composite material C1 containing a large amount of natural fibers that has been attracting attention from the viewpoint of CO2 reduction in recent years, and to reduce waste.
Moreover, in any process, since the general equipment such as a crusher, a continuous kneader, an injection molding machine, a pelletizer, and a compression molding machine is used, the equipment cost is not particularly burdened, and the existing processing is performed. The facility can be introduced with slight modifications.

  Among the above processes, in the crushing process of Step S1, the length of the natural fiber after cutting is slightly shorter than the length of the composite material C1 of 10 to 50 mm, but most of the natural fibers have a length of 10 mm or less. Therefore, the strength of the recycled composite materials C2 and C3 can be prevented from greatly decreasing.

In the heating / kneading step of step S2, polyolefin or regenerated polyolefin having high heat solubility is introduced as the second thermoplastic resin R into the composite material C1. Therefore, the composite material C1 and the second thermoplastic resin R can be quickly mixed by heating.
Further, natural fibers are evenly dispersed in the first thermoplastic resin and the second thermoplastic resin R of the composite material C1 melted by heating and kneading, and these resins are impregnated between the fibers. Accordingly, there is no portion that is not impregnated with resin due to concentration of natural fibers, so that local strength deficiency can be prevented. This effect is particularly effective when manufacturing a small recycled composite material.
In addition, the strength of the recycled composite materials C2 and C3 can be further improved by adding an adhesive strength improver.

Next, in the molding process of step S3, since either the injection / molding process of step S4 or the compression / molding process of step S5 can be selected, the recycled composite material C2 which is a pellet-like semi-finished product or the final product is used. Any one of the recycled composite materials C3 can be selected according to the application. In the recycled composite material C2, the length of the natural fiber tends to be shorter than that of the composite material C1 because the cutting is performed twice. However, by combining the lengths of each cut, the length of the fiber is reduced. it is avoided that excessive shortened, it is possible to reproduce the composite C 2 is provided with a strength comparable to composites C1.
Hereinafter, the composite material regeneration processing method according to the present embodiment will be described with reference to examples.

Next, configurations of specific examples and comparative examples will be described. Of course, the present invention is not limited by this illustration.
First, a plurality of sample pieces having the configuration of the example were prepared, and a tensile test, a bending test, and a Charpy impact test were performed to obtain test results. The sample piece was prepared by mixing polypropylene pellets (MFI = 55 g / 10 min) and natural fiber (kenaf), and performing the crushing process in step S1 to the extrusion process in step S4-1. Each test was performed on a plurality of types of samples in which the content of natural fibers in the sample piece was changed. In addition, the shape of a sample piece follows each shape prescribed | regulated to the following JIS specification. Moreover, said polypropylene pellet was used as a comparative example.

Each test was performed according to the method defined in the following JIS standard.
(1) Tensile test (see Table 1)
The test was conducted using a 1BA type small test piece in accordance with JIS K 7162.
(2) Bending test (see Table 2)
It implemented based on JISK7171.
(3) Charpy impact test (see Table 3)
In accordance with JIS K 7111-1, the test piece type 1 was notched and edgewise.
The test results are shown below. In addition, all the values in Tables 1 to 3 are values defined in the above-mentioned JIS standard, and are average values for a plurality of sample pieces.

As shown in Table 1, in the tensile test, the maximum strength and elastic modulus of each example are higher than those of the comparative example. Moreover, among the examples, the maximum strength and elastic modulus tend to increase as the fiber content increases.
Next, as shown in Table 2, the same tendency as described above was observed in the bending test.
Furthermore, as shown in Table 3, in the Charpy impact test, a sample containing kenaf having an MPP concentration of 0% by weight and a fiber content of 25% by weight shows the maximum impact value. This understands that there is an upper limit in increasing the fiber content . In addition, in any of the examples in Tables 1 to 3, the impact value of each of the examples is higher than that of the comparative example. Moreover, although the maximum intensity | strength improved by adding MPP in the case of the same fiber content rate in an Example, it resulted in a fall rather. When re-molding was performed, the maximum strength and impact value were slightly reduced compared to the case where this was not performed, but the values were almost the same.
From the above results, it can be said that the sample containing kenaf has improved strength, elastic modulus, and impact value as compared with polypropylene pellets containing no kenaf, and has excellent properties overall. Further, it can be seen that the fiber content and the presence or absence of MPP may be appropriately adjusted so as to be suitable for various applications.

The composite material and test results according to the embodiment of the present invention will be described in detail with reference to FIG.
FIG. 2 is an actual photograph of the recycled composite material pellet according to the embodiment of the present invention.
A plurality of recycled composite pellets containing kenaf having a fiber content of 30% by weight were prepared, and a test result was obtained by conducting a tensile test, a bending test and a Charpy impact test, respectively. The recycled composite material pellet according to Example 1 is a mixture of a kenaf composite material (fiber content of about 55% by weight) and a recycled polyolefin pellet as a second thermoplastic resin, and from the crushing step of Step S1 to Step S4-3. It was prepared by an injection molding process (see FIG. 2). The recycled composite material pellet has a diameter of 4 mm, and the kenaf composite material is cut into a length of 15 mm in the cutting process of step S1-1 and the pellet forming process of step S4-2.
The recycled polyolefin pellets are mainly composed of polyethylene and polypropylene, and also contain a small amount of polystyrene and polyethylene terephthalate. And MFI is about 10-20 g / 10min.
As a comparative example, recycled polyolefin pellets were used. The results are shown in Table 4. In addition, all the values in Table 4 are values defined in the above-mentioned JIS standard, and are average values for a plurality of recycled composite material pellets.

  The recycled composite material pellets of Example 1 were remolded to produce a plurality of recycled composite material pellets according to Example 2, and the test results were obtained by performing a tensile test, a bending test, and a Charpy impact test, respectively. The results are shown in Table 4.

As shown in Table 4, according to Example 1, the strengths in the tensile test and the bending test are improved by about 29% and 92%, respectively, with respect to the comparative example. The coefficient of variation (strength standard deviation (MPa) / strength (MPa) × 100 (%)) in the tensile test and bending test was 1.9% and 3.5%, respectively, with respect to the comparative example. Since these are sufficiently small values, it can be seen that there is little variation for each of the recycled composite material pellets according to Example 1, and that they are homogenized. Further, the impact value in the Charpy impact test is reduced by about 50%.
Further, according to Example 2, the strength in the tensile test and the bending test showed the same value as in Example 1, and the strength decrease due to re-molding was slight.

A plurality of recycled composite pellets containing kenaf having a fiber content of 25% by weight were prepared and subjected to a tensile test, a bending test, and a Charpy impact test, respectively, to obtain test results. Other configurations are the same as those of the recycled composite material pellet according to the first embodiment. As a comparative example, recycled polyolefin pellets in Table 4 were used. The results are shown in Table 5. In addition, all the values in Table 5 are values defined in the above-mentioned JIS standard, and are average values for a plurality of recycled composite material pellets.

  The recycled composite material pellets of Example 3 were reshaped to produce a plurality of recycled composite material pellets according to Example 4, and the test results were obtained by performing a tensile test, a bending test, and a Charpy impact test, respectively. Moreover, the reproduction | regeneration polyolefin pellet of Table 4 was used as a comparative example. The results are shown in Table 5.

A plurality of recycled composite pellets containing kenaf having a fiber content of 25% by weight and MPP having a concentration of 2% by weight were prepared, and a tensile test, a bending test, and a Charpy impact test were performed to obtain test results. The other structure is the same as that of the recycled composite material pellet according to Example 1, and the recycled polyolefin pellet shown in Table 4 was used as a comparative example. The results are shown in Table 5.

  The recycled composite material pellet of Example 5 was remolded to produce a plurality of recycled composite material pellets according to Example 6, and a tensile test, a bending test, and a Charpy impact test were performed to obtain test results. Moreover, the reproduction | regeneration polyolefin pellet of Table 4 was used as a comparative example. The results are shown in Table 5.

As shown in Table 5, according to Example 3, the strengths in the tensile test and the bending test are improved by about 25% and 73%, respectively, with respect to the comparative example. The coefficient of variation in the tensile test and the bending test was 4.3% and 1.4%, respectively, relative to the comparative example. From this, it can be seen that there is little variation for each of the recycled composite material pellets according to the plurality of Examples 3, and that they are homogenized.
Further, according to Example 4, the strength in the tensile test and the bending test and the impact value in the Charpy impact test showed the same values as in Example 3, and the decrease in strength and impact value due to re-molding was slight. It was.

As shown in Table 5, according to Example 5, the strengths in the tensile test and the bending test are improved by about 24% and 79%, respectively, with respect to the comparative example.
Further, according to Example 6, the strength in the tensile test and the bending test showed the same value as in Example 5, and the decrease in strength due to re-molding was slight.

The recycled composite material and the test result according to the embodiment of the present invention will be described in detail with reference to FIG.
3A and 3B are actual photographs of the front and back surfaces of the recycled composite cylinder base according to Example 7, respectively.
A plurality of recycled composite cylinder bases containing kenaf having a fiber content of 27% by weight were prepared and subjected to a bending test and a compression test, and test results were obtained. The recycled composite cylinder base according to Example 7 is a 1: 1 ratio of the kenaf composite (fiber content of about 55% by weight) and the same recycled polyolefin pellet used in Example 1 as the second thermoplastic resin. The fibers were mixed at a ratio to adjust the fiber content to about 27% by weight, and were prepared by the crushing process of step S1 to the compression molding process of step S5-2. In the cutting process of step S1-1, the kenaf composite material was cut to a length of 30 mm. Further, the size of the recycled composite cylinder base is about 400 mm × 400 mm × 35 mm, and has a radial groove on the surface as shown in FIG. 3 (a), and a lattice on the back as shown in FIG. 3 (b). Ribs are provided.
The test was performed on the divided pieces obtained by dividing the entire cylinder base along the thickness direction so as to have an area of about ½, the flat plate portion on the front surface, and the rib crossing portion on the back surface. Among these, the bending test was implemented about the division | segmentation piece and the flat part of the surface, and the compression test was implemented about the rib crossing part of the back surface. The used indenter is a 20 mm diameter iron bar with divided pieces and flat plate portions, and is a circular flat plate with 120 mm diameter at the rib intersections. As a comparative example, a conventional material composed of recycled polyolefin was used. The results are shown in Table 6. In addition, all the values in Table 6 are values defined in the above-mentioned JIS standard, and are average values for a plurality of recycled composite cylinder cylinders.

As shown in Table 6, according to Example 7, the maximum point loads at the split piece, the flat plate portion, and the rib crossing portion are improved by about the same level, about 80%, and about 55% compared to the comparative example, respectively. . In the split piece, the rib crossing portion on the back surface was largely broken. This is due to the concentration of stress at the rib intersection, but such a decrease in the maximum point load is expected to be improved by changing the bending radius of the lattice portion.
Further, the elastic moduli at the divided pieces, the flat plate portions, and the rib intersection portions were improved by about 225%, 370%, and 175%, respectively.

From the above, the recycled composite material pellets according to Example 1 to Example 6 and the recycled composite material cylinder base according to Example 7 are both improved in strength and elastic modulus compared to the comparative example, and the elastic modulus is particularly dramatic. The result was improved. In addition, since the recycled composite material pellets according to Example 1, Example 3, and Example 4 are homogenized, the natural fibers are sufficiently kneaded into the first thermoplastic resin and the second thermoplastic resin. Is represented. In other words, this indicates that the natural fiber is cut to a length suitable for kneading.
Therefore, the present invention sufficiently solves the problem of providing a regeneration processing method and a regeneration processing apparatus for a composite material having a kneaded fiber length and high strength.

  The composite material regeneration processing method and the regeneration processing apparatus according to the present invention are not limited to those shown in this embodiment. For example, the natural fiber is not particularly limited as long as it is a plant having cellulose as a main component, and hemp, bamboo, cotton, banana leaf, palm skin, etc. may be used.

  The inventions described in claims 1 to 5 are applicable as a regeneration processing method and a regeneration processing apparatus for a composite material formed by combining natural fibers and a thermoplastic resin.

C1: Composite material C2, C3: Recycled composite material R: Second thermoplastic resin

Claims (5)

In the recycling treatment method of a composite material formed by combining natural fibers and a first thermoplastic resin,
The natural fiber is a long fiber having a length of 10 mm or more,
The first thermoplastic resin is impregnated between the fibers of the natural fiber,
The content of the natural fiber in the composite material is 40 to 80% by weight,
A crushing step of crushing the composite material so that its length is 10 to 50 mm;
A heating and kneading step of charging the second thermoplastic resin into the crushed composite material and kneading while heating;
A molding step of molding the kneaded composite material,
The crushing step includes a cutting step of cutting the composite material, and a selection step of extracting only the composite material having a length of 10 to 50 mm from the cut composite material,
Said forming step, e Bei an extrusion step extruding the composite material is kneaded from the nozzle, the pelleting step of cutting the composite material extruded to the length of 10~50mm formed into pellets, and
The method for reclaiming a composite material, wherein a length of the natural fiber contained in the composite material formed into a pellet after the pellet forming step is longer than 10 mm.   The method for reclaiming a composite material according to claim 1, wherein the second thermoplastic resin is selected from polyolefin, polystyrene, regenerated polyolefin and regenerated polystyrene. The method for reclaiming a composite material according to claim 1 or 2, wherein a content ratio of the natural fiber in the composite material after the heating / kneading step is 10 to 50% by weight. .   The said natural fiber is a vegetable natural fiber which has a cellulose as a main component, The reproduction | regeneration processing method of the composite material of any one of Claim 1 thru | or 3 characterized by the above-mentioned. A recycling apparatus for a composite material formed by combining natural fibers and a first thermoplastic resin,
The natural fiber is a long fiber having a length of 10 mm or more,
The first thermoplastic resin is impregnated between the fibers of the natural fiber,
The content of the natural fiber in the composite material is 40 to 80% by weight,
Cutting means for cutting the composite material so that its length is 10 to 50 mm;
Sorting means for extracting only the composite material having a length of 10 to 50 mm from the cut composite material;
A heating / kneading means for charging the kneaded material while charging the second thermoplastic resin into the selected composite material;
Kneaded with a forming shape means you molding the composite material,
Before KiNaru shaped means is provided with an extrusion nozzle for extruding the composite material is kneaded, and a cutter for cutting the composite material extruded to a length of 10 to 50 mm, and
The length of the natural fiber contained in the composite material cut by the cutter is longer than 10 mm.