JP2003340894A - Recycling apparatus for coated resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycling apparatus which can reduce a heat damage of a resin at a lower cost, and recycle a coated resin molding. <P>SOLUTION: The recycling apparatus 10 for the coated resin molding has an injection unit 20 which melts the fragments of the crushed coated resin molding and injects the molten resin, a mold 30 for solidifying/molding the molten resin injected from the injection unit 20, and a pulverization unit 40 which is arranged between the injection unit 20 and the mold 30 and has a mesh form the pulverizing a coating film 13 by making the coating film 13 and the molten resin pass through the unit 40. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycling apparatus for recycling coated resin molded products.

[0002]

2. Description of the Related Art In recent years, it has become important to recycle resin molded products from the viewpoint of effective utilization of resources and environmental protection.

Since the surface of a resin molded product is often coated, various techniques for recycling the coated resin molded product have been proposed (Japanese Patent Laid-Open No. 7-2051).
52 and Japanese Patent Laid-Open No. 11-10645). For example, a crushed piece of a coated resin molded product is melted in an extruder and the molten resin material is kneaded. Then, the molten resin material is pelletized through an extrusion process while collecting and separating the unmelted coating film by a wire mesh filter incorporated in the extruder. The pelletized recycled resin is melted again in the injection molding machine and used for molding recycled molded articles.

[0004]

In the technique for recycling a resin molded product using an extruder, a molten resin material is kneaded at a high temperature of 230 ° C. to 250 ° C. and a high shearing force in an extrusion process. Therefore, it is apt to undergo oxidative deterioration under the influence of heat damage, which may lead to a decrease in strength of the recycled molded product. In addition, when the recycled molded product is molded, the resin material is melted again in the injection molding machine, which may further deteriorate the resin material.

Further, since the extruder is used, the equipment cost and the processing cost are inevitably high.

The present inventors pay attention to the fact that recycled molded products are generally molded by injection molding, and if the coating film is made finer in the injection molding machine, the extrusion process by the extruder can be abolished and the molten resin material can be abolished. The inventors have found that the heat damage to the product can be reduced as much as possible and the cost can be reduced, and the present invention has been completed.

Therefore, an object of the present invention is to provide a recycling apparatus capable of recycling coated resin molded products while reducing the heat damage to the resin material and reducing the cost.

[0008]

The objects of the present invention are achieved by the following means.

(1) Injection means for melting and injecting a crushed piece of a coated resin molded product, a mold for solidifying and molding the molten resin material injected from the injection means, the injection means and the mold. And a refining means having a mesh shape for refining the coating film and the molten resin material by permeating the coating film and the molten resin material.

(2) The recycle processing apparatus for a coated resin molded article according to (1) above, wherein the miniaturization means includes means for adjusting the temperature of the molten resin material to be transmitted. .

(3) The miniaturizing means is detachably attached between the injection means and the mold, and the recycling treatment for the coated resin molded article according to the above (1) is performed. apparatus.

[0012]

The present invention configured as described above has the following effects.

According to the first aspect of the invention, the fact that the resin is melted by the injection means is used, and the miniaturization means is incorporated between the injection means and the mold. The extruder kneading and pelletizing steps can be omitted. With the omission of the extrusion process, it is possible to reduce the heat damage to the resin material and reduce the cost, and it is possible to recycle the coated resin molded product. Further, the mesh shape provided in the miniaturization means can miniaturize the coating film to improve the appearance quality of the recycled molded product.

According to the second aspect of the present invention, by adjusting the temperature of the refining means, it is possible to prevent the flow reduction due to the pressure loss when the molten resin material flows down through the refining means, and the recycled molded product. The quality of can be improved.

According to the third aspect of the invention, it is easy to exchange the mesh shape of the miniaturization means.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (A) is a process diagram showing a recycling process in an embodiment using a recycling processing apparatus for coated resin molded products according to the present invention, and FIG. 1 (B) uses an extruder. It is a flowchart showing a general recycling process.

As shown in FIG. 1B, in a general recycling process, first, a resin molded article with a coating film is crushed and the coating film is peeled off. The size of the peeled coating film is 0.5 mm on average, and the larger one is 2 mm to 3 mm.
It is a degree. After the coating film is peeled off, the crushed pieces are melted in the extruder and the molten resin material is kneaded. The molten resin material is pelletized while the unmelted coating film is collected and separated by a wire mesh filter built in the extruder. The pelletized recycled resin is melted again by an injection molding machine and injection-molded. Through these steps, recycled molded products are molded.

On the other hand, as shown in FIG. 1 (A), the recycling process in the embodiment is the same as a general recycling process up to the point of crushing a resin molded product with a coating film to peel off the coating film. However, the steps of kneading and pelletizing with an extruder are omitted. Then, when the crushed pieces are melted and injection-molded, the coating film is miniaturized to form a recycled molded product. The type of injection molding machine is not particularly limited, but a screw type injection molding machine which is widely used and is capable of sufficiently melting a resin is preferable.

FIG. 2 is a schematic configuration diagram showing a recycling apparatus 10 for coated resin molded products according to the present invention, FIG.
4 is a cross-sectional view showing the main parts of the recycling apparatus 10, FIG.
(A) and (B) are a front view and a side sectional view showing the miniaturization unit 40 of the recycling apparatus 10, and FIG.
FIG. 5B is a front view showing a state where the cartridge 43 of the miniaturization unit 40 is taken out from the unit main body 42.
FIG. 6 is an exploded perspective view showing a cartridge 43.

As shown in FIG. 2, the recycling apparatus 10 for painted resin molded products uses an injection molding machine composed of an injection unit and a mold. An injection unit 20 (corresponding to an injection unit) for melting and injecting a crushed piece of a resin molded product, a mold 30 for solidifying and molding a molten resin material injected from the injection unit 20, a coating film and a molten resin material. A miniaturization unit 4 having a mesh shape that miniaturizes the coating film by transmitting it.
0 (corresponding to the miniaturization means). The miniaturization unit 40 is arranged between the injection unit 20 and the mold 30. The details will be described below.

The resin molded article with a coating film is, for example,
A bumper or the like can be exemplified, but the present invention is not limited to this. The resin molded product with a coating film is crushed by a press or the like. As the resin molded product is crushed, the coating film peels off from the material of the molded product. The size of the crushed pieces is not limited as long as the size is such that the crushed pieces can be melted by the injection unit 20.

The resin material of the molded article to be recycled is not particularly limited as long as it is a thermoplastic resin material, and is, for example, PP (polypropylene).

A thermosetting resin material is used as the resin material of the coating film. For example, acrylic resin or the like. In the case of a coating film made of acrylic resin, it does not decompose unless it is heated to about 400 ° C. In the temperature range for injection molding, even if the thermoplastic resin is melted, the coating film made of the thermosetting resin is not melted.

As shown in FIG. 3, the injection molding machine of the embodiment is a screw line type. The injection unit 20
A hopper 21 for feeding the crushed pieces 11 and the virgin material 12
And a heating cylinder 23 provided with a band heater 22
A screw 24 housed in the heating cylinder 23 and driven to rotate, and a plunger portion 2 filled with a molten resin material.
5 and a nozzle 27 having an injection port 26 at its tip and connected to the plunger portion 25. The resin as a raw material is fed from the hopper 21 into the heating cylinder 23 by the rotating screw 24, and is heated and melted while being kneaded. The coating film 13 exists in the molten resin material without melting. The heating and melting temperature varies depending on the resin, but is 210 ° C. to 250 ° C., for example. After the molten resin material is filled in the plunger portion 25, the molten resin material is injected from the injection port 26 to the miniaturization unit 40, further passes through the miniaturization unit 40, and is injected to the cavity 31 in the mold 30.

As shown in FIGS. 4A and 4B, the miniaturization unit 40 includes a unit body 42 having a flow path 41 and having a substantially cylindrical shape, and a cartridge 4 having a mesh shape.
3 and 3. The inlet port 41a of the flow path 41 communicates with the injection port 26, and the outlet port 41b communicates with the gate of the mold 30. The cartridge 43 is inserted into an insertion hole 44 formed in a substantially central portion of the unit body 42 in the longitudinal direction. The insertion hole 44 is formed up to a position crossing the flow path 41. The cartridge 43 inserted in the insertion hole 44 is
It is fixed to the unit main body 42 via a fixing means (not shown). A pressure sensor 45 for measuring the pressure of the molten resin material flowing down in the flow path 41 is attached at a position upstream of the insertion hole 44. A detection signal from the pressure sensor 45 is input to a controller (not shown), and the pressure state of the molten resin material is constantly monitored.

As shown in FIG. 5 (A), the cartridge 4
3 is configured to be detachable from the unit main body 42. As shown in FIG. 5B, the cartridge 43 is
It has a pair of substantially T-shaped case bodies 51 and 52, and a mesh-shaped screen 53 sandwiched between the case bodies 51 and 52. The screen 53 is a case body 5
The windows 51a and 52a formed in the first and the second 52 are exposed.
When the cartridge 43 is attached to the unit body 42, the screen 53 is located on the way of the flow path 41 (see FIG. 4A). The screen 53 is not particularly limited in constituent material as long as it has a mesh shape, but can be composed of, for example, a metal mesh. The size of the openings of the metal net is determined by trial and error according to the target dimensions of the coated film 13 pieces after miniaturization. In the embodiment, 60
A wire mesh having a mesh and an opening size of 250 μm was used. Moreover, the number of metal nets may be one, but a plurality (for example, five) may be used. According to the screen 53 composed of a plurality of metal nets, the coating film 13 can be prevented from slipping through and the durability of the screen 53 can be enhanced. The coating film 13 contained in the molten resin material without melting is finely divided by the screen 53 when passing through the screen 53.

The miniaturization unit 40 includes means for adjusting the temperature of the molten resin material that is transmitted. As the temperature adjusting means, various known means can be used. For example, as shown in FIG.
A band heater 55 for heating the unit body 42 is provided. The unit main body 42 is heated by the band heater 55, and the molten resin material that flows through the flow path 41 and permeates the screen 53 is heated. By heating the unit main body 42, the screen 53 itself is also heated. The temperature of the molten resin material and the screen 53 is adjusted to a constant temperature by using a thermostat or a blower (not shown). In the illustrated example, the cooling pipe 56 is wound around the outer peripheral surface of the unit body 42 in consideration of the case of cooling the permeating molten resin material.

Since the residence time of the resin in the miniaturization unit 40 is short, it is possible to set the temperature of the miniaturization unit 40 higher than the temperature of the injection unit 20. However, it is preferable not to raise the temperature of the miniaturization unit 40 in order to prevent the resin from being affected by heat damage. Further, if the temperature of the miniaturization unit 40 is increased, the flow velocity of the resin at the sprue of the die 30 changes, which may cause a molding defect such as a beard. Therefore, the temperature of the molten resin material and the screen 53 which pass through the miniaturization unit 40 is the same as the temperature of the injection unit 20 (for example,
It is preferably 210 to 250 ° C. The controller controls the temperature adjusting means such as the band heater 55 so that the temperature of the miniaturization unit 40 becomes the same as the temperature of the injection unit 20.

The miniaturization unit 40 is the injection unit 20.
And the mold 30 are detachably attached. The miniaturization unit 40 is detachably fixed to the mold 30 side via a fixing means (not shown). As shown by the chain double-dashed line in FIG. 4B, the unit body 4 of the miniaturization unit 40.
An attachment portion 57 is attached to the unit 2 in a replaceable manner. The attachment part 57 has a shape that matches the shape of the injection unit 20. Miniaturization unit 40
Is pressed relative to the injection unit 20,
The nozzle 27 of the injection unit 20 is fitted in the flow path 41 of the miniaturization unit 40. Attachment part 57
The unit main body 42 can be commonly used for injection units having different shapes by exchanging. The ejection port 26 at the tip of the nozzle 27 may be brought into direct contact with the screen 53.

Next, the operation of this embodiment will be described.

The resin molded product with a coating film, which is a waste material, is crushed by a press or the like to obtain a crushed piece 11. This crushed piece 1
1 and the virgin material 12 are put into the hopper 21 of the injection unit 20 at a predetermined ratio. The mixing ratio of the crushed pieces 11 is set to an appropriate value from the viewpoint of balancing the amount of recovery and the amount of supply and the change of the material specifications of the virgin material 12. For example, the crushed pieces 11 are mixed in about 30% with respect to the total amount.

The raw material resin is the rotating screw 2.
4 is fed from the hopper 21 into the heating cylinder 23, and is heated and melted at 210 ° C. to 250 ° C. while being kneaded. The thermoplastic resin and the virgin material 12 which are the base materials of the waste material melt, but the coating film 13 made of the thermosetting resin does not melt. The molten resin material including the coating film 13 is filled in the plunger portion 25, and then is injected from the injection port 26 into the miniaturization unit 4.
It is ejected to 0.

The refining unit 40 is preheated so that the molten resin material and the screen 53 which are to be permeated have the same temperature as that in the injection unit 20 (for example, 210 ° C. to 250 ° C.). The molten resin material injected from the injection port 26 flows into the flow path 41 in the unit main body 42 from the inlet port 41a and reaches the screen 53 through the flow path 41. The coating film 13 which has not been melted passes through the screen 53 together with the molten resin material when it passes through the screen 53.
It is miniaturized by the mesh shape of.

Molten resin material and finely divided coating film 13
Passes through the flow path 41, reaches the gate of the mold 30 from the outlet port 41b, and is injected into the cavity 31 in the mold 30. The injected molten resin material is cooled in the mold 30 for a certain period of time and solidified. Then, the mold 30 is opened and the recycled molded product is taken out.

When such injection molding is continued, the coating film 13 which cannot be made fine by the screen 53 stays on the upstream side of the screen 53. Then, since the passage resistance of the screen 53 increases, the pressure of the molten resin material on the input side to the screen 53 increases. Pressure sensor 4
5 measures this pressure. The controller constantly monitors the pressure state of the molten resin material based on the signal from the pressure sensor 45. Then, when the measured pressure reaches the threshold value, the controller determines that it is time to replace the screen 53, and notifies the operator to that effect by a lamp or a buzzer.

The replacement of the screen 53 is performed as follows.
First, as shown in FIG. 5A, the fixing state between the cartridge 43 and the unit main body 42 is released, and the cartridge 4
3 is pulled out from the insertion hole 44. Next, as shown in FIG. 5 (B), the pair of case bodies 51 and 52 are separated, and the screen 53 sandwiched between the case bodies 51 and 52 is removed. Next, the new screen 53 is sandwiched between the pair of case bodies 51 and 52. Then, the cartridge 43 is reinserted into the insertion hole 44, and the cartridge 43 and the unit main body 42 are fixed, whereby the replacement of the screen 53 is completed.

Since the miniaturization unit 40 is detachably attached between the injection unit 20 and the mold 30, a system in which the screen 53 is exchanged by exchanging the entire miniaturization unit 40 is also adopted. it can. Even with this method, the screen 53 can be easily replaced.

In the general recycling process shown in FIG. 1B, the melt is melted again by the injection molding machine through the extrusion process by the extruder. Further, since the extrusion process by the extruder is originally intended for kneading, the residence time of the resin is longer than the residence time in the injection molding machine. For this reason, the thermoplastic molten resin material is frequently subjected to heat damage, and is in a state of being easily oxidatively deteriorated.

On the other hand, in the present embodiment, the fact that the resin is melted by the injection molding machine is used, and since the miniaturization unit 40 is incorporated in the injection molding machine, the steps of kneading and pelletizing by the extruder are omitted. it can. With the omission of the extrusion process, the crushed pieces 11 are heated only while they are passing through the screw 24 of the injection molding machine. Also, the residence time of the resin is shorter than the residence time in the extrusion process by the extruder. Therefore, heat damage to the thermoplastic molten resin material can be reduced, and oxidative deterioration can be suppressed.
Since it is difficult for oxidative deterioration to occur, it is possible to suppress a decrease in strength of the recycled molded product. Since the decrease in strength of the resin base material is reduced, it is possible to eliminate the mixing of the reinforcing material and reduce the mixing amount. Since the coating film 13 is made of a thermosetting resin, it is less affected by heat damage than a thermoplastic resin.

According to the strength measurement result by the Izod impact test, the strength was improved by about 20% in this embodiment in which the extrusion step was omitted.

Further, since the extruder is not used, the facility cost is not generated, and the processing cost is about 30% lower than the case where the extruder is used.

Therefore, it is possible to recycle the coated resin molded product while reducing the heat damage to the resin material and reducing the cost.

FIG. 6 is a diagram showing the results of inspecting the appearance quality of recycled molded products.

The number of coating film pieces remaining on the surface of a certain area of the recycled molded product was counted and the size thereof was measured. FIG. 6 shows the distribution of the size of the coating film piece and the number of samples n. Inspection of appearance quality is performed by the miniaturization unit 4
No. 0 was provided with the screen 53, and the comparative example was produced without the screen 53.
For the screen 53, five metal meshes having 60 mesh and an opening size of 250 μm were used.

Referring to FIG. 6, when the screen 53 was not used and the ratio was proportional, the coating film pieces remaining on the surface of the recycled molded product had an average size of about 1.8 mm. On the other hand, in the case of the example in which the coating film 13 was miniaturized using the screen 53, the coating film pieces remaining on the surface of the recycled molded product had an average size of about 0.3 mm. With the screen 53 selected in the example, the maximum size of the coating film piece remaining on the surface of the recycled molded product was about 0.8 mm, and the size of the coating film piece could be suppressed to 1 mm or less.

When the size of the coating film piece was 1 mm or less, the coating film piece was not projected from the surface when the surface of the recycled molded product was observed with a magnifying microscope. Rather, when the coating film piece was on the surface, extremely minute recesses (about 0.1 mm) appeared around the coating film piece. However, with such a degree of depression, the general consumer does not feel uncomfortable in the appearance of the coating after painting, and there is no problem in product quality.

Therefore, in the embodiment, the screen 53
As a result, the coating film 13 can be miniaturized to a sufficient size, and the appearance quality of the recycled molded product is improved.

FIG. 7A is a conceptual diagram showing the result of measuring the pressure loss of the molten resin material passing through the miniaturization unit 40, and FIG. 7B shows an example of the size of the miniaturization unit 40. It is a conceptual diagram.

The inlet pressure P1 and the outlet pressure P2 of the miniaturization unit 40 were measured. In FIG. 7 (A), the inlet pressure P
The relative pressure of the outlet pressure P2 when 1 is set to 1.0 is shown. The pressure loss is measured by the miniaturization unit 40.
Temperature is the same as the temperature in the injection unit 20 (210 ° C
To 250 ° C.) and the refining unit 40
The temperature was not adjusted and the comparison was performed.

As shown in FIG. 7B, the longitudinal dimension L1 of the unit main body 42 of the miniaturization unit 40 is 300 m.
m, and the thickness L2 of the cartridge 43 is 30 mm. The screen 53 has 60 mesh and the size of the opening is 2.
Five pieces of 50 μm wire mesh were used.

Referring to FIG. 7A, the miniaturization unit 4
In the case of the proportionality in which the temperature of 0 is not adjusted, the inlet pressure P1
The relative pressure of the outlet pressure P2 to 0.7 is
A pressure drop of about 30% occurred. On the other hand, the miniaturization unit 4
In the case of the example in which the temperature of 0 was adjusted and maintained at 210 ° C. to 250 ° C., the relative pressure of the outlet pressure P2 to the inlet pressure P1 was 0.95, and a pressure loss of about 5% occurred.

If the relative pressure of the outlet pressure P2 to the inlet pressure P1 is 0.9, that is, the pressure loss is suppressed within about 10%, the product quality is not affected.

Therefore, in the embodiment, the temperature of the miniaturization unit 40 is the same as the temperature of the injection unit 20 (21
Since the temperature is adjusted to 0 ° C. to 250 ° C.), it is possible to prevent the flow reduction due to the pressure loss when the molten resin material flows down the miniaturization unit 40, and the quality of the recycled molded product is improved.

[Brief description of drawings]

FIG. 1 (A) is a process diagram showing a recycling process in an embodiment using a recycling processing apparatus for a coated resin molded product according to the present invention, and FIG. 1 (B) shows an extruder. It is a process diagram showing a general recycling process.

FIG. 2 is a schematic configuration diagram showing a recycling apparatus for a coated resin molded product according to the present invention.

FIG. 3 is a cross-sectional view showing a main part of the recycling apparatus.

4 (A) and 4 (B) are a front view and a side sectional view showing a miniaturization unit of a recycling apparatus.

5A is a front view showing a state where a cartridge of a miniaturization unit is taken out from a unit main body, and FIG. 5B is an exploded perspective view showing the cartridge.

FIG. 6 is a diagram showing a result of inspecting appearance quality of a recycled molded product.

FIG. 7 (A) is a conceptual diagram showing the result of measuring the pressure loss of the molten resin material passing through the miniaturization unit, FIG.
(B) is a conceptual diagram showing an example of the size of the miniaturization unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Recycle processing apparatus for painted resin molded products 11 ... Grinding pieces 13 ... Coating film 20 ... Injection unit (injection means) 24 ... Screw 30 ... Mold 40 ... Miniaturization unit (miniaturization means) 42 ... Unit body 43 ... Cartridge 53 ... Screen 55 ... Band heater (means for adjusting temperature of molten resin material) 56 ... Cooling pipe (means for adjusting temperature of molten resin material) 57 ... Attachment portion

Claims (3)

[Claims] 1. An injection unit for melting and injecting a crushed piece of a coated resin molded product, a mold for solidifying and molding a molten resin material injected from the injection unit, and the injection unit and the mold. A recycle processing apparatus for a painted resin molded article, which is disposed between the two and has a meshing means having a mesh shape for making the coating film and the molten resin material finer by permeating the coating film and the molten resin material. 2. The recycling apparatus for a coated resin molded article according to claim 1, wherein the miniaturization means includes means for adjusting the temperature of the molten resin material that permeates. 3. The recycling apparatus for a coated resin molded article according to claim 1, wherein the miniaturization means is detachably attached between the injection means and the mold.