JPH06270152A - Method and apparatus for removing film of particulate material - Google Patents

Abstract

PURPOSE:To mechanically remove a film in low cost by a means capable of eliminating a problem in a conventional mechanical method. CONSTITUTION:A casing 4 storing a particulate material having a film as a material to be treated is rotated to press trhe material to be treated to the inner peripheral surface 4a of the casing 4 by centrifugal force and the pressing and scraping actions of the friction pieces 9a and scraping pieces 9b relatively rotating with respect to the casing are applied to the layer of the material to be treated formed on the inner peripheral surface 4a by centrifugal force and stirring action is applied to the material to be treated. By repeatedly applying these actions, the film of the particulate material is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing a coating film of a granular material, and more specifically, on a surface of a granular material such as powder or granular material in a state of being integrated with the granular material. The present invention relates to a method for removing a coating film of a granular material for removing an existing coating from the granular material, and an apparatus used for carrying out the method.

[0002]

2. Description of the Related Art In recent years, for example, waste products of resin bumpers for automobiles have been recycled. In this case, a thermoplastic resin such as polypropylene is used as the recyclable bumper resin. By the way, when the waste product is actually recycled, the surface of the resin bumper is coated with a thermosetting resin (or a coating containing a thermosetting resin as a main component) via a primer made of a thermoplastic resin. Since a film is formed by coating and the coating film remains after recycling, a problem occurs. Therefore, the coating film is a resin (hereinafter, referred to as a base resin) that constitutes the bumper body when the waste product is recycled. Need to be removed from. Therefore, various means for removing the coating film have been developed. For example, a method has been developed in which the coating film is chemically separated using a solvent that dissolves the coating film or an agent that decomposes without affecting the base resin. Further, a method of physically separating the coating film by heating the waste product under a high temperature condition in which the base resin melts but the coating film does not melt has been developed. However, the implementation of these methods is very expensive and several mechanical coating removal methods have been developed which can be performed at a lower cost than these methods. For example, after crushing the waste product into powder or granules, the powder or granules together with water for transportation into a stone mill type grinder (more specifically, a pair of ring-shaped grindstones facing each other vertically with a certain clearance. There is a mechanical method using a grinder, in which only the coating film is scraped off from the powder and granules by a grinding action of a grinder to form a powder. Further, there is a mechanical method using a cone mill including a cylindrical side wall that vibrates slightly at a constant amplitude and frequency and a cone-shaped floor having a slight gap between the cylindrical side wall and the side wall. According to this cone mill, a compressive force is applied to the powder or granules by passing the powder or granules through a gap that is changed by microvibration of the cylindrical side wall, thereby causing a displacement at the interface between the base resin and the coating film. (While the compressive force causes plastic deformation of the base resin, the compressive force causes cracks without plastic deformation of the coating film, so that the base resin and the coating film Deviation occurs at the interface), based on the deviation,
The powder or granular material can be in a state where the coating film is easily separated from the base resin. Then, the powder or granular material in which the coating film is easily peeled off is provided in a pin mill (that is, an apparatus in which a disk having a large number of pins protruding therein is rotatably provided in a cylinder having a large number of pins protruding inwardly). ), The coating film can be separated from the powder or granular material.
In this way, when the coating film such as the coating film is present in a non-fusion-bonded state on the surface of the powder or granular material such as the base resin, the powder or granular material can be manufactured at a low cost. When it is desired to remove at a cost, the above-mentioned mechanical method using a grinder or a cone mill is used.

[0003]

However, the mechanical method using a grinder has the following problems. That is, since the granules are passed into the attritor along with water for transportation, it is necessary to separate the water from the granules after the film is removed, which is a troublesome post-treatment (specifically, the granules). There was a problem that the body had to be dried). Furthermore, since grinding is performed only by the part where the powder and granules come into direct contact with the grinding stone, the powder and granules cannot be removed by passing the powder and granules through the grinder only once. However, there was a problem that the efficiency was very poor, such as the need to pass through a grinder. Further, since the grindstone will be worn or chipped with the lapse of processing time, the grindstone must be replaced many times, and there is also a problem that the grindstone may be mixed into the processed material. Further, the mechanical method using a cone mill has the following problems. That is, when the granular material is subjected to a corn mill, the granular material is passed through the gap and a compressive force is applied to the granular material, so that the coating is easily separated from the granular material. The coating is not separated from the powder and granules only by subjecting the body to a corn mill.To separate the coating from the powder and granules, the powder and granules after being subjected to the corn mill can be subjected to post-treatment such as further pin milling. It was necessary, and there was the problem of poor efficiency. The present invention has been made by paying attention to such an actual situation, and it is a mechanical coating film removing method which can be implemented at a low cost, but a conventional mechanical method (that is, a mechanical method using a grinder). Method or mechanical method using a cone mill)
Means that can solve the problem in, that is, it is possible to eliminate the troublesome post-treatment such as drying treatment and troublesome grindstone exchange, which were necessary in the conventional mechanical method, and moreover than the conventional mechanical method. It is an object of the present invention to provide a means capable of improving the film removal efficiency.

[0004]

A method of removing a coating film of a granular material according to the present invention (hereinafter referred to as a method of the present invention) is a coating film existing on the surface of the granular material in an integrated state with the granular material. Is a method for removing a coating film of a granular material for removing from the granular material,
By rotating a casing that contains the coated powder or granular material as a material to be treated, the material to be treated is pressed against the inner peripheral surface of the casing by a centrifugal force, and the member formed on the inner peripheral surface by the pressing force. The treatment material layer is imparted with a pressing action of a friction piece rotating relative to the casing and a scraping action of a scraping piece, and by repeating an agitation action on the material to be treated, the powder is obtained. It is characterized in that the film is removed from the granules.

In the above-mentioned method of the present invention, it is preferable that the material to be treated having a particle diameter of 0.05 to 20 mm is housed in the casing.

[0006] Further, a material to be treated having a hard coating film as the coating film on the surface of the granular material of the thermoplastic resin is housed in the casing, and the treatment temperature in the casing is controlled by the powder. It is preferable to set in a range from a temperature higher than the low temperature embrittlement temperature of the granules to a temperature lower than the softening point of the powder granules.

The apparatus for removing a coating film of a granular material according to the present invention (hereinafter referred to as an apparatus of the present invention) comprises a coating film existing on the surface of the granular material in a non-fusion-integrated state with the granular material. In order to remove from the granular material, a casing for accommodating the coated granular material as a material to be treated is rotatably provided, and the material to be treated contained in the casing is caused by centrifugal force to cause an inner circumference of the casing. A drive device for rotating the casing so as to be pressed against the surface is provided, and a friction piece and a scraping piece are provided in the casing so as to be rotatable relative to the inner peripheral surface.

In the above-mentioned device of the present invention, it is preferable that the outer peripheral surface of the friction piece has irregularities.

Further, it is preferable that the inner peripheral surface of the casing has irregularities.

[0010]

According to the method of the present invention, since the casing for containing the coated granular material as the material to be treated is rotated, the centrifugal force based on the rotation causes the layer of the material to be treated to be formed on the inner peripheral surface of the casing. Formed, imparting a pressing action of the friction piece and a scraping action of the scraping piece to the material layer to be treated, and
Since applying the stirring action to the material to be treated will be repeated in the casing, not only the friction piece and the scraping piece act on the powder and granular material in the casing, but also the powder and granular material. The particles also act on each other, and the combined effect of them allows the coating film on the surface of the granular material to be effectively peeled off or scraped off. That is, under the combined action, when a strong force is partially applied to the surface of the material to be processed based on the pressing action or the like, the coating film is cracked or damaged, and as a result, the coating film is formed. , The adhesive strength with the granular material is weakened and peeled off,
If the coating is soft, it will be scraped off.

[0011]

According to the method of the present invention, therefore, the mechanical method can be carried out at a low cost as compared with the conventional chemical method or physical method, while the conventional mechanical method is used. The problems (i.e., problems caused by a grinder or a cone mill) can be solved as follows. That is, comparing the method of the present invention with the case of using an attritor, in the method of the present invention, since the water for transportation and the grindstone that have been conventionally used are not used, the conventional troublesome treatment (that is, the post-treatment of water) , And grindstone replacement) is unnecessary, and the grindstone is not mixed in after the film is removed.
Since the coating on the surface of the granular material is effectively peeled off or scraped off in the casing, it becomes unnecessary to apply the granular material to the device many times as in the conventional case, and work efficiency is improved. It will be better than before. Further, comparing the method of the present invention with the case of using a corn mill, in the past, it was necessary to subject the powder or granular material after being subjected to a corn mill to a pin mill, etc., but to subject it to post-treatment, according to the method of the present invention, Since the coating on the surface of the powder or granules is effectively peeled off or scraped off in the casing, the post-treatment that was necessary in the past is no longer necessary, and in this case as well, the work efficiency is improved as compared with the conventional one. Become. Furthermore, in the conventional method, since the coating is mainly peeled from the granular material by applying pressure to the granular material with a coating, the granular material is soft and the coating is hard with respect to the coated granular material. Only in some cases, the conventional method could be effectively applied, but in the method of the present invention,
Since friction and pressure are applied to the coated granular material to cause abrasion and shear separation, not only when the granular material is soft and the coating is hard, but also when the granular material is The method of the present invention can be effectively applied to a coated granular material having various combinations such as a hard coated granular material having a soft coating.

In the above-mentioned method of the present invention, the particle size:
If the material to be treated having a thickness of 0.05 to 20 mm is housed in the casing, the work efficiency of removing the coating film is particularly improved. This is because if the material to be treated having a particle size smaller than 0.05 mm is to be accommodated in the casing,
While it becomes difficult to separate the peeled coating film and the granular material, if the material to be treated having a particle diameter of more than 20 mm is accommodated in the casing, the stirring efficiency of the material to be treated becomes poor and Since the contact efficiency between the materials also deteriorates, the efficiency of peeling the coating film from the powder or granules deteriorates. Therefore, the particle size:
This is because if the material to be treated having a size of 0.05 to 20 mm is housed in the casing, both the above-mentioned unfavorable conditions can be avoided.

Further, a material to be treated having a hard coating film on the surface of the thermoplastic resin powder particles is contained in the casing, and the processing temperature in the casing is controlled by the powder particles. If the temperature is set to a temperature higher than the low temperature embrittlement temperature of the body to a temperature lower than the softening point of the powder or granular material, the film can be more effectively removed. Because, when the treatment temperature is higher than the softening point, the thermoplastic resin forming the powder or granular material is softened.
On the other hand, when the treatment temperature is lower than the low temperature embrittlement temperature while melting and becoming unfavorable conditions for removing the coating film, the powder itself is easily embrittled by low temperature embrittlement. This is an unfavorable condition when only the film is removed. Therefore, if the processing temperature in the casing is set within the above-mentioned temperature range, both the above-mentioned unfavorable conditions can be avoided.

Further, according to the device of the present invention having the above-mentioned structure, the above-mentioned actions and effects can be effectively produced. Particularly, according to the device of the present invention in which the outer peripheral surface of the friction piece is formed with irregularities, the pressing action of the friction piece with respect to the material layer to be processed more effectively occurs, by the pressing action,
Cracks and scratches are more effectively generated in the coating film, and the work efficiency of removing the coating film is further improved. Further, according to the device of the present invention in which unevenness is formed on the inner peripheral surface of the casing, slippage of the material layer to be processed with respect to the inner peripheral surface of the casing is suppressed, and the slip suppression suppresses the work efficiency of the film removal. It will be even better.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

As a resin bumper for automobiles, a recyclable thermoplastic resin (polypropylene resin in this embodiment) has recently been used. by the way,
On the surface of the bumper, a coating film containing a thermosetting resin as a main component (in this embodiment, via a primer made of a thermoplastic resin (chlorinated polyolefin in this embodiment))
A coating film containing melamine resin as a main component and aluminum, titanium oxide, mica, or the like as a filler is formed if necessary, and if the coating film remains after recycling, a problem occurs. , When the waste is recycled, the resin that constitutes the bumper body (hereinafter,
Base resin). Therefore,
In the case of actually recycling the waste product of the bumper, the waste product is a powder or granular material (for example, particle size: 10).
mm particles), the powder particles are supplied as a material to be treated into the apparatus of the present invention shown in FIGS. 1 and 2, and the coating film is removed from the base resin in the apparatus. To do so.

In FIG. 1, reference numeral 1 is a base, and a vertical rotation shaft 2 is attached to the base 1. A processing chamber 3 for removing the coating film is provided on the upper end of the vertical rotation shaft 2.
A cylindrical casing 4 having a bottom is formed concentrically, and a drive device 5 including an electric motor 5a, a transmission 5b, and the like is interlockingly connected to a lower end thereof, so that the casing 4 has an inner periphery. The material to be processed in the casing 4 is rotationally driven so as to be pressed against the surface 4a by a centrifugal force (rotation direction: see arrow in the figure). still,
The rotation speed of the casing 4 can be adjusted so as to be a rotation speed suitable for removing the coating film.

A cylinder 6 for supplying a material to be treated is provided above the casing 4 so that a lower end of the cylinder 6 for supplying a material to be treated faces an upper opening of the casing 4.
The processed material from the processed material supply feeder 7 is supplied into the casing 4 via the processed material supply cylinder 6. Further, the material to be processed after being processed in the casing 4 is transported by air through a pipe 8a which is drawn from the lower part of the casing 4 to the outside of the casing 4 through the inside of the material supplying cylinder 6. Then, the base resin and the coating film are separated by being sent into a classifier 8b (for example, a cyclone) and being subjected to a classifying process in the classifier 8b. A dam portion 4b is provided at the upper opening of the casing 4 to prevent the supplied processing target material from jumping out.

A support shaft 10a which is provided so as to penetrate the central portion of the rotary shaft 2 so that its upper end portion is located inside the casing 4.
A support 10b is attached to the upper end of the. A conical portion 10d is formed on a part of the support 10b, and the conical portion 10d is arranged concentrically with the cylindrical body 6. At the tip of the support 10b, the material to be treated is pressed against the inner peripheral surface 4a of the casing 4 by the centrifugal force generated by the rotation of the casing 4, and the inner peripheral surface 4a thereof is pressed.
As shown in FIG. 2, the friction pieces 9a for pressing the material layer to be formed and imparting a strong frictional force are separated from each other by an appropriate distance (for example, 10 mm) in the rotation direction of the casing 4. Therefore, it is provided so as to be rotatable relative to the casing 4. Further, inside the casing 4, scraping pieces 9b for scraping, dispersing and stirring the material to be treated from the material layer to be treated are provided at appropriate intervals in the rotating direction of the casing 4, as shown in FIG. (For example, 7 mm),
It is provided so as to be rotatable relative to the casing 4.
The outer peripheral surface of the friction piece 9a and the casing 4
Roughening is formed on the inner peripheral surface of the.

The friction piece 9a has an inclined surface formed so that the gap between the friction piece 9a and the casing 4 becomes narrower toward the rotation direction side of the casing 4. Further, the scraping piece 9b is
The gap between the casing 4 and the casing 4 is wider toward the rotation direction side of the casing 4, and the acting surface thereof is gradually widened to have a wedge shape or a comb tooth shape. Then, the casing 4 and the friction piece 9a and the scraping piece 9b are relatively rotated so that the pressing action of the friction piece 9a and the scraping action of the scraping piece 9b are pressed against the inner peripheral surface 4a of the casing 4. It is designed to be applied to the material layer to be treated.

A passage 11 for allowing a heating medium or a cooling medium to flow into the support 10b, the friction piece 9a, and the scraping piece 9b is formed in the support shaft 8a. It is connected to 13.

When the method of the present invention is carried out using such an apparatus of the present invention, the casing 4 (inner diameter: 340 mm) for accommodating the powdered particles with the coating as the material to be treated is appropriately driven by the drive unit 5. Rotation speed (for example, 680 rpm)
Since it is driven to rotate, a layer of the material to be treated is formed on the inner peripheral surface 4a of the casing 4 by the centrifugal force based on the rotation, and the pressing action of the friction piece 9a and the scraping piece 9b are formed on the layer of the material to be treated. The scraping action and the stirring action on the material to be treated are repeated in the casing 4, so that in the casing 4, the friction piece 9a is applied to the powder or granular material as the material to be treated. And not only the scraping piece 9b acts, but also the powder and granules interact with each other, and the coating on the surface of the powder and granules is effectively peeled off or scraped off by their combined action. The processing temperature in the casing 4 is in the range of -20 to 150 ° C (preferably 20 to 80 ° C) by supplying an appropriate heating medium or cooling medium (usually cooling medium) to the passage 11. Set to. Under such temperature conditions, the softening point (168 ° C.) of the thermoplastic resin (that is, the polypropylene-based resin) that constitutes the powder and granules is lower than the softening / melting of the thermoplastic resin, and the powder is prevented. It becomes possible to prevent the particles themselves from being embrittled at a low temperature and crushed to the particles themselves, and the removal of the coating film can be preferably performed. Further, since the particle diameter of the material to be treated is 10 mm, which is an appropriate size, it is not difficult to separate the peeled coating film and the granular material in the subsequent process, and the stirring efficiency of the material to be treated is deteriorated. In addition, the efficiency of contact between the materials to be treated does not deteriorate, and the efficiency of peeling the coating film from the granular material does not deteriorate.

In order to separate the material to be treated in the casing 4 (that is, to separate the powder and granules from the coating), a classifier 8b is used as in the above embodiment. However, several embodiments are possible. For example, the material to be treated after the film removal is discharged from the casing 4 in a batch process, and the material to be treated is sieved (sieve mesh: 3.36).
mm) may be separated for an appropriate time (for example, 10 minutes).

Needless to say, the effective range of the processing temperature in the casing 4 varies depending on the type of material to be processed. For example, tetralofluoroethylene, which is one of the fluorinated resins, does not soften up to 327 ° C, saturated polyester does not soften up to 250 ° C, and polyimide does not soften up to 300 ° C. Can be raised to near their respective softening points depending on the type of the material to be treated.

It is also possible to supply an inert gas into the casing 4 to remove the coating film of the powder or granular material in a state where the atmosphere inside the casing 4 is clean.

Further, the method of the present invention is not limited to the case of recycling the waste resin bumper for automobiles as in the above-mentioned embodiment, but also various kinds formed on the surface of the powder or granular material made of various resins or various metals. It can also be applied when removing the coating.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an apparatus used for carrying out the method of the present invention.

FIG. 2 is a sectional view taken along the line EE in FIG.

[Explanation of symbols]

 4 casing 4a inner peripheral surface 5 drive device 9a friction piece 9b scraping piece

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[Procedure amendment]

[Submission date] June 18, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The apparatus for removing a coating film of a granular material according to the present invention (hereinafter, referred to as an apparatus of the present invention) includes a coating existing on the surface of the granular material in an integrated state with the granular material. In order to remove it from the casing, the casing containing the coated powder or granular material as a material to be treated is rotatably provided, and the material to be treated contained in the casing is pressed against the inner peripheral surface of the casing by centrifugal force. As described above, a drive device for rotating the casing is provided, and a friction piece and a scraping piece are provided in the casing so as to be rotatable relative to the inner peripheral surface.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

In order to separate the material to be treated in the casing 4 (that is, to separate the powder and granules from the coating), a classifier 8b is used as in the above embodiment. However, several embodiments are possible. For example, the material to be treated after the film removal is discharged from the casing 4 in a batch process, and the material to be treated is sieved (sieve mesh: 3.36).
mm) may be separated for an appropriate time (for example, 5 minutes).

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

[0024] The processing temperature in the casing within 4, the valid range depending on the type of material to be treated is changed is had
Needless to say.

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (6)

[Claims] 1. A method for removing a coating of a powder or granular material, which comprises removing a coating existing on the surface of the powder or granular material in an integrated state with the powder or granular material from the powder or granular material. By rotating a casing (4) that contains granules as a material to be treated, the material to be treated is pressed against the inner peripheral surface (4a) of the casing (4) by centrifugal force, and the inner peripheral surface is pressed by the pressing force. The material layer formed on (4a) is provided with the pressing action of the friction piece (9a) rotating relative to the casing (4) and the scraping action of the scraping piece (9b), and A method for removing a coating film of a powder or granular material, which comprises removing the coating film from the powder or granular material by repeatedly applying a stirring action to the treatment material. 2. The method for removing a coating film of powder or granules according to claim 1, wherein a material to be treated having a particle diameter of 0.05 to 20 mm is housed in the casing (4). 3. A material to be treated, which has a hard coating film on the surface of a granular material of a thermoplastic resin as the coating film, is housed in the casing (4), and The method for removing a coating film of a granular material according to claim 1, wherein the treatment temperature is set in a range from a temperature higher than a low temperature embrittlement temperature of the granular material to a temperature lower than a softening point of the granular material. 4. The powdered or granular material with a coating is treated in order to remove from the powder or granular material a coating that exists on the surface of the powder or granular material in a non-fused and integrated state with the powder or granular material. A casing (4) for accommodating as a material is rotatably provided, and the material to be treated contained in the casing (4) is pressed against the inner peripheral surface (4a) of the casing (4) by centrifugal force. A drive device (5) for rotating the casing (4) is provided, and a friction piece (9) is provided in the casing (4).
a) and a scraping piece (9b) which are provided so as to be rotatable relative to the inner peripheral surface (4a). 5. The powdery-particle coating removing device according to claim 4, wherein the friction piece (9a) is provided with irregularities on its outer peripheral surface. 6. The powdery-particle coating removing device according to claim 4, wherein the casing (4) is provided with irregularities on an inner peripheral surface thereof.