JP3177371B2 - How to recycle painted resin products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling a resin product, for example, a coated resin product such as a bumper or a side molding used as a functional part such as a decoration or a cushion for an automobile or the like.

[0002]

2. Description of the Related Art In recent years, the recycling of resin products has been called out due to an increase in environmental issues and interest in resource recycling. For example, even in the automotive industry, there is a problem in the process of producing resin products such as bumpers and side moldings. Attention has been focused on recycling resin products separated and recovered from defective products and end-of-life vehicles.

[0003] In many cases, resin products such as bumpers and side moldings are coated on the surface of the product in order to improve the appearance and quality. For example, the skin of the bumper is made of a thermoplastic resin material such as polypropylene resin. A coating is formed on top. This coating film is a thermosetting resin, for example, an amino polyester type, an amino acrylic type, a polyester urethane type,
These are acrylic urethane-based resins, and these resins are in a liquid state before the curing reaction, but a crosslinked structure is provided by a baking coating process. This is because of its strong and dense structure, the coated resin bumper has excellent chemical resistance, heat resistance, scratch resistance, weather resistance and surface gloss.

However, when the bumper is pulverized and pelletized to obtain a recycled material, a piece of the coating film is mixed with the polypropylene resin material constituting the material of the resin product, and the polypropylene resin mixed with the coating film piece is mixed. In the molding process using materials, the coating film pieces impede the fluidity of the molten resin, causing molding defects such as "burn", "weld mark", and "bubbles" in the resin product, and The coating film pieces that emerge on the surface have problems such as impairing the appearance of the resin product.

[0005] Further, since there is almost no interaction between the coated film piece and the polypropylene resin serving as the base resin, the coated film piece prevents kneading and unifying in the regenerated resin, and the mechanical properties of the resin product are reduced. Is significantly reduced.

For this reason, it is necessary to remove the coating when recycling the coated resin product.

[0007] As a method of removing a coating film, there is a method disclosed in Automotive Technology Vol. 46. No. 5,
1992. Mechanical as disclosed on pages 3-9,
Classified into physical and chemical methods.

[0008] The mechanical coating film removing method is, for example, a method in which fine particles of abrasive are sprayed onto the surface of a coating film formed on a resin product by using compressed air to destroy and remove the coating film and attached matter. There are a blast method and a screen mesh method in which a resin product is finely pulverized and then filtered through a screen mesh under heating and melting to remove mixed coating film pieces without melting.

The shot blasting method is excellent in toxicity and environmental safety because the coating film is removed by friction, impact, etc., but requires a large amount of processing time, and the coating film removing efficiency is not sufficient. Processing is difficult. The screen mesh method is excellent in toxicity and environmental safety because the coating film pieces are removed by filtration.However, clogging of the screen mesh occurs, the extrusion pressure increases significantly, the output decreases, the production decreases, and the coating decreases. The removal efficiency of the film pieces is not sufficient, and there is a problem that the screen mesh needs to be replaced in order to avoid a decrease in production efficiency due to blockage by the screen mesh.

The method of physically removing a coating film uses a halogen-based solvent or various organic solvents, and removes the coating film by utilizing solvent penetration into the interface between the coating film and the material and swelling of the coating film by the solvent. It is inferior in environmental safety, has relatively low coating film removal efficiency and processing ability, and may be deteriorated to a material.

Since these mechanical and physical coating film removal methods have low coating film removal efficiencies, resin products using the recycled resin material obtained by these methods have favorable appearance and mechanical properties of the products. And the range of application is greatly limited.

The chemical coating film removing method is, for example, an organic salt method in which a coating film is chemically decomposed and removed by cutting an ether bond near a crosslinking point of the coating resin with a mixed solution of ethanol and water containing an organic salt. There is.

This method has problems in secondary treatment such as wastewater treatment, and has problems such as low treatment efficiency and inefficiency.

An apparatus for removing a coating film of a resin product is disclosed in Japanese Patent Application Laid-Open No. 5-337941, and FIG. 7 is a front view, and FIG. 8 is a sectional view taken along line AA of FIG. Surface peeling devices have been proposed.

In this peeling apparatus, a resin product, for example, a side molding 32 is transported between rotating bodies 33 and 34 made of foamable synthetic resin by a pair of transporting rollers 31, and the transport speed V of the side molding 32 is increased. By setting the rotation peripheral speed to be lower than the rotational peripheral speeds of 33 and 34, cutting and high frictional force are applied to the coating 32a of the side molding 32 and the double-sided tape 32b, and the coating 32a on the surface of the side molding 32
Further, the double-sided tape 32b is cut and peeled, and the side molding 32 is discharged to the outside by the pair of transport rollers 31.

This device is made of a rotating foaming synthetic resin.
Since the rotating bodies 33 and 34 are brought into contact with the resin products, the rotating bodies 33 and 34 are brittlely broken and generate dust, which is not preferable in the work environment, and is not suitable for bent or curved resin products. There is a defect.

[0017]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to recycle a coated resin product which makes it possible to obtain a high quality recycled resin product having excellent coating film removal efficiency, environmental safety and processing ability. It is to provide a method.

[0018]

According to the present invention, there is provided a method for recycling a coated resin product, wherein the coated resin product is rolled between opposed rolls so as to be processed into a substantially flat plate shape. And a coating material-side roll and a resin material-side roll in which the plate-shaped material obtained in the pretreatment step is disposed to face each other.
Rolling by a roll device that is greater than the peripheral speed of the side roll , and a roll rolling process step of applying a shear shear stress between the resin material and the coating film and peeling the coating film from the resin material, A pulverizing step of pulverizing the resin material from which the coating film has been peeled to obtain a pulverized material, and the coated resin product is disposed opposite to each other between the rolls so as to be continuously rolled into a flat plate shape. Resin material side roll and said resin
Film-side roll with a peripheral speed greater than the peripheral speed of the material-side roll
Rolling and peeling off the coating film from the resin material by applying shear shear stress between the resin material and the coating film by rolling, and the resin material peeling off the coating film in the roll rolling and coating film peeling process And a pulverizing step of pulverizing the material to obtain a pulverized material.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of recycling a coated resin product according to the present invention will be described below by taking as an example a case where a coated resin bumper, which is a large component among automobile resin components, is collected and recycled.

FIG. 1 is a schematic explanatory view showing each step of a method for recycling a coated resin product in the present embodiment, and shows defective products generated during the production and assembly of a resin bumper.
A resin product recovery step a for separating and recovering from a scrap car and the like, a pre-processing step b for processing the recovered resin bumper into a flat plate shape,
A roll rolling treatment step c for peeling off the coating film from the plate-shaped material obtained in the pretreatment step b by rolling with a roll device,
A crushing process step d for crushing the resin material from which the coating film has been peeled off,
It has a pelletizing step e for pelletizing the pulverized material obtained in the pulverizing step d, and a forming step f for commercializing the pellets obtained in the pelletizing step e as a material.

Next, each step will be described sequentially. The symbol w shown in the resin product recovery step a in FIG. 1 is a painted resin bumper which is removed and recovered from in-process defective products and end-of-life vehicles and metal parts are removed. The bumper w is a thermoplastic resin such as a polypropylene resin. This is a coated resin product in which a coating film of a thermosetting resin such as an aminopolyester-based, aminoacryl-based, polyester-urethane-based, or acrylic-urethane-based resin is formed on a resin material composed of:

The bumper w recovered in the resin product recovery step a and from which the metal parts have been removed is formed into a flat plate shape in the pretreatment step b in order to improve the efficiency of removing the coating film in the next roll rolling step c. Processed.

In this processing, if necessary, the bumper w is cut into appropriate sizes, heated and rolled between opposing rolls to form a substantially flat plate. As shown in FIG. 1, the rolling device 10 includes a plurality of opposed rolls
a: 10a ', 10b: 10b', 10c: 10c ',
10d: 10d 'and a heating means (not shown). Each roll is sequentially changed in shape as shown in each sectional view in FIG. 1 (a), and the roll is rolled while heating the supplied bumper w. To obtain a flat plate-shaped material 1.

As shown in FIG. 2, a side view of a rolling device 11 instead of the rolling device 10 includes a plurality of opposed rolls 11a: 11a ', 11b: 11b' and heating means (not shown). ), And a roll 12a and a cylindrical cutting blade 12b opposed to each other are disposed at the last stage, and 11a:
11a ', 11b: A step of cutting and removing a convex portion (not shown) such as a rib projecting from the back surface of the bumper w flattened by 11b' is obtained to obtain a flat plate-shaped material 1 having a smoother flat plate shape. Such a configuration is also possible.

The flat material 1 obtained by such a rolling device 10 or 11 is heated by a heating means during the rolling process by each roll, so that the processing is easy and the plasticized flat material 1 is heated. Maintains a flat plate shape.

Next, the roll rolling treatment step c for peeling the coating film 2 from the flat material 1 obtained in the pretreatment step b will be described.

As shown in FIG. 1, the roll device 13 used in the rolling process step c is made of a metal which is disposed to face each other and has a mirror-finished outer peripheral surface or a chrome-plated resin material side roll. 14 and a coating-side roll 15.

The resin material side roll 14 and the coating film side roll 15
That is , the rotation is driven such that the peripheral speed of the coating film-side roll 15 pressing against the surface of the coating film 2 is higher than the peripheral speed of the resin material-side roll 14 pressing against the surface of the resin material 3.

Therefore, the flat material 1 supplied between the resin material side roll 14 and the coating film side roll 15 is
Rolls 15 and 15
A shear shear stress is applied between the resin material 3 and the coating film 2 based on the relative peripheral speed difference therebetween, and the coating film 2 peels from the resin material 3.

As shown in the front view of FIG. 3A and the side view of FIG.
4 is tapered so that its diameter increases as it moves toward the edge 14b, and the diameter 14d at the edge 14b is larger than the diameter 14c at the center.

Similarly, as shown in the front view of FIG. 3 (a) and the side view of FIG. 3 (b), the film side roll 15 becomes larger as the edge 15a near the edge of the roll 15 shifts to the edge 15b. Rolling between these rolls 14 and 15 causes the central portions of both side edges of the flat plate material 1 to protrude outward and deform, but the rolls 14 and 15 are near the edges 14a. , 15a are formed in a tapered shape having a larger diameter as they move to the edges 14b, 15b, so that the gap between the edges 14a, 15a near the edges of both rolls 14, 15, which presses both side edges of the flat plate-shaped material 1. And a sufficient pressing force by the two rolls 14 and 15 is secured at both side ends of the flat plate-shaped material 1, so that sufficient shear shear stress acts on both ends of the flat plate-shaped material 1 and peeling of the coating film 2 occurs. Achieved.

In addition, one of the resin material side roll 14 and the coating film side roll 15 near one roller edge 14a or 15a
It is also possible to form only the taper shape whose diameter increases as it moves to the edge.

Reference numeral 16 in FIG. 1 denotes a brush, a scraper, or the like, which slidably contacts the outer peripheral surface of the coating film side roll 15 and scrapes the coating film 2 adhered to the surface of the roll 15.

FIG. 4 is an explanatory view showing another embodiment of the roll device 13. The same reference numerals are given to portions corresponding to those in FIG. Is coated with an elastic member, for example, a rubber 15e, thereby increasing the friction coefficient between the coating film-side roll 15 and the coating film 2 of the plate-shaped material 1, and is applied between the resin material 3 and the coating film 2. In addition to securing shear shear stress to improve the peeling of the coating film 2, the function of preventing the coating film 2 from adhering to the coating film side roll 15 due to the deformation of the rubber 15 e due to the pressing on the flat material 1. It is intended to improve the workability by facilitating biting when the flat material 1 is supplied.

FIG. 5 is an explanatory view showing another embodiment of the roll device 13. The same reference numerals are given to portions corresponding to those in FIG. 15 and the resin material 3 at a position downstream of the resin material side roll 14.
A pair of transport rolls 17 for sandwiching and transporting the coating film 2;
18, and an adhesive tape feeding reel 19 facing the other side of one transporting roll 17 and an adhesive tape collecting reel 20 for winding the adhesive tape 21 fed from the adhesive tape delivering reel 19 are provided. The adhesive tape 21 fed from the feeding reel 19 by the coating film 2
There is provided a coating film collecting means for pressing and recovering the coating film 2 by adhesion.

As means for removing the peeled coating film 2 adhered to the resin material 3 from the resin material 3, appropriate means such as pressing a rotating brush against the resin material 3 or blowing compressed air may be provided. It is possible.

The coating film 2 is peeled off in the roll rolling step c, and the rolled resin material 3 is pulverized by a shredder or the like in the next pulverizing step d to become the pulverized material 4.

The pulverized material 4 is supplied to an extruder in a subsequent pelletizing step e. The extruder, for example, advances the pulverized material 4 put into the hopper in the barrel by rotation of a screw, and heats it with a band heater or the like, melts it while advancing in the barrel, and extrudes it from the die to form pellets of a certain shape. 5 is manufactured. At this time, the remaining coating film pieces are removed by a screen mesh provided at the tip of the barrel. If the screen mesh can be automatically replaced, the processing capacity can be further increased and the productivity can be improved.

To the pellets 5 obtained in the pelletizing step e, pellets made of a resin such as virgin polypropylene are added as required in the next molding step f, and the pellets again become resin products such as bumpers.

In the above embodiment, the bumper w, which is a coated resin product, is obtained in the pretreatment step b to obtain the flat plate-shaped material 1 and the flat material 1 is coated from the resin material 3 by the roll rolling step c. 6, the bumper w which has been recovered in the resin product recovery step a, and from which the metal portion has been removed is divided as necessary, roll-rolled, and coated from the resin material as shown in FIG. Roll rolling to peel off film
The coating film peeling step g is performed by a pretreatment step b and a roll rolling treatment step c.
It is also possible to provide instead of.

As shown schematically in FIG. 6, a rolling / coating stripping apparatus 22 used in the roll rolling / coating stripping step g includes a plurality of opposed rolls 22a: 22
a ', 22b: 22b' and heating means, and at least one stage, in this embodiment, two stages, opposed resin material side rolls and coating side rolls 23a: 24
a, 23b: 24b, each having a resin material side roll 23
b, 24b, respectively, opposite coating film side rolls 23a,
24a is driven to rotate at a large peripheral speed. The resin material side rolls 23b and 24b and the coating film side rolls 23a and
The vicinity of at least one roll edge of 4a can be formed in a tapered shape having a larger diameter as moving toward the edge direction.

The bumper w supplied to the rolling / coating stripping device 22 thus configured is heated by the heating means and is connected to the rolls 22a: 22a ', 22a connected in plural stages.
b: Rolled successively to 22b ', deformed into a flat plate shape, and subsequently led into resin material side rolls 23b, 24b and coating film side rolls 23a, 24a, further rolled by these rolls, and opposed to each other between the rolls The coating film 2 is peeled off from the resin material 3 by the shear shear stress applied between the resin material 3 and the coating film 2 based on the difference in the peripheral speeds, and the resin material 3 is supplied to the next crushing process step d. It is also possible.

Further, similarly to the above embodiment, the coating film side roll 23
The outer periphery of a, 24a may be covered with an elastic member, for example, rubber, or the adhesive tape fed from the adhesive tape feed reel may be pressed against the coating film by the coating film side rolls 23a to 24a to collect and collect the coating film 2. In addition, it is also possible to provide a coating removing means by pressing a rotating brush against a resin material or blowing compressed air.

Further, at a position upstream of the resin material side roll and the coating film side roll facing each other, the rolls 22a: 22
a ', 22b: bumper w flattened by 22b'
It is also possible to add a step of cutting and removing a convex portion (not shown) such as a rib projecting from the back surface of the substrate.

In the above embodiment, the pulverized material 5 made of the resin material pulverized in the pulverizing step d is formed into a pelletizing step e.
When heating to melt and pelletize, the remaining coating film pieces were removed by a screen mesh. Instead of the pelletizing step e, the pulverized material obtained in the pulverizing step e was separated by a pin mill or a specific gravity separator. It is also possible to separate the part that made up the resin material and the part that made up the coating film with the device, and it can also reduce the number of steps such as melting and extrusion and cost compared to pelletizing. It is possible.

[0046]

According to the method for recycling a coated resin product according to the present invention described above, the coated resin product is rolled between opposing rolls to be processed into a flat plate shape, and then the peripheral speed is different. Rolled by the coating film side roll and the resin material side roll, applying shear shear stress between the resin material and the coating film and peeling the coating film from the resin material. After easily processing into a flat shape,
The coating film can be removed from the resin product, and a high quality recycled resin product with extremely high coating film removal efficiency can be obtained with excellent productivity and at low cost. Since it is not necessary, it has no toxicity, is excellent in environmental safety and has excellent processing ability, and has effects unique to the present invention, and greatly contributes to recycling of coated resin products in a wide field.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of a method for recycling a coated resin product according to the present invention.

FIG. 2 is an explanatory view of a pretreatment step in a method for recycling a coated resin product according to the present embodiment.

FIG. 3 is an explanatory view of a pretreatment step.

FIG. 4 is an explanatory view of a roll rolling process step.

FIG. 5 is an explanatory view of a roll rolling process step.

FIG. 6 is a schematic explanatory view showing another embodiment of the method for recycling a coated resin product according to the present invention.

FIG. 7 is a schematic explanatory view of a conventional coating film peeling apparatus.

FIG. 8 is a sectional view taken along line AA in FIG. 7;

[Explanation of symbols]

 a resin product recovery step b pre-treatment step c roll rolling step d crushing step e pelletizing step f forming step g roll rolling / coating peeling step w bumper 1 flat plate 2 coating 3 resin material 4 crushed material 5 pellet DESCRIPTION OF SYMBOLS 10 Rolling device 10a Roll 10a 'Roll 10b Roll 10b' Roll 10c Roll 10c 'Roll 10d Roll 10d' Roll 11 Rolling device 11a Roll 11a 'Roll 11b Roll 11b' Roll 12a Roll 12b Cutting blade 13 Roll device 14 Resin material side roll 14a Near the edge 14b Edge 15 Coating roll 15a Near the edge 15b Edge 17 Transport roll 18 Transport roll 19 Tape feeding reel 20 Adhesive tape

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-337941 (JP, A) JP-A-56-449623 (JP, A) JP-A-62-35809 (JP, A) 269743 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29B 17/00-17/02 C08J 11/00-11/28

Claims (9)

(57) [Claims] 1. A pre-treatment step of rolling a coated resin product between opposing rolls to process it into a substantially flat plate shape, and a flat-plate material obtained in the pre-treatment step is provided with a coating material disposed oppositely. comprising a <br/> film-side roll and a resin material side roll, the coating film side b
Roll speed is greater than the circumferential speed of the resin material side roll. <br/> Rolling is performed by a roll device, and a shear force is applied between the resin material and the coating film to peel the coating film from the resin material. 1. A method for recycling a coated resin product, comprising: a roll rolling step of performing a roll rolling step; and a pulverizing step of obtaining a pulverized material by pulverizing a resin material from which a coating film has been removed in the roll rolling step. 2. The method for recycling a coated resin product according to claim 1, further comprising the step of cutting and removing a projecting portion projecting from the resin product rolled between opposing rolls in the pretreatment step. 3. A resin material side row which is disposed opposite to a coated resin product in a continuous manner between rolls into a flat plate shape.
Of the peripheral speed greater than the peripheral speed of the
Rolling and peeling the coating film from the resin material by applying shear shear stress between the resin material and the coating film by rolling with the roll on the coating film side A pulverizing step of pulverizing the exfoliated resin material to obtain a pulverized material. 4. The method for recycling a coated resin product according to claim 3, wherein, in the roll rolling and coating film peeling step, the protruding portion projecting from the resin product rolled between the rolls is cut and removed prior to the supply to the roll device. 5. The coating resin according to any one of claims 1 to 4, wherein at least one of the coating film side roll and the resin material side roll has a tapered shape whose diameter increases in the vicinity of the roll edge toward the edge direction. How to recycle products. 6. The method for recycling a coated resin product according to claim 1, wherein an outer periphery of the coating film side roll is covered with an elastic member. 7. A pair of transport rolls for nipping and transporting a resin material and a coating film at a position downstream of the coating material side roll and the resin material side roll which are disposed opposite to each other, and the transport rolls are adhesive tape feeding reels. 7. The method for recycling a coated resin product according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive tape fed from the step (a) is pressed against the coating film to collect the coating film. 8. A pelletizing step in which a pulverized material obtained by pulverizing in the pulverizing treatment step is heated and melted, and a remaining coating film piece is removed by filtration by a screen mesh to be pelletized to form a pellet. 7. The method for recycling any one of the coated resin products of item 7. 9. The method according to claim 1, wherein the pulverized material obtained by the pulverization in the pulverization treatment step is separated into a portion constituting the resin material and a portion constituting the coating film by a separating device. How to recycle one painted resin product.