JP3177372B2 - 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 from a resin product is disclosed in Japanese Patent Application Laid-Open No. 5-337941, and FIG. 8 is a front view, and FIG. 9 is a cross-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, comprising the steps of: pretreating a coated resin product into a substantially flat plate shape by a pressing device; comprising a paint film side roll and a resin material side roll the resulting tabular material are oppositely disposed at, the coating film side roll peripheral velocity of the resin material side roll
Rolling by a roll device that is larger than the peripheral speed , and applying a shear shear stress between the resin material and the coating film to separate the coating film from the resin material, A pulverizing step of pulverizing the separated resin 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 order to improve the efficiency of removing the coating film in the next roll rolling step c in the pretreatment step b. For example, it is processed into a strip shape.

In this process, as shown in FIG. 2, if necessary, the bumper w is fitted and held in the support member 10 fitted in the concave portion of the bumper w. ′, A band-shaped body w divided by a cutter 11 in a substantially U-shape
a is processed into a rectangular plate shape by a press device.

The press device 12 has, for example, as shown in FIG. 3, a lower die 13 on which the band-shaped body wa is placed, and an upper die 14 which descends and rises to contact and separate from the lower die 13. Is provided with a positioning portion 13A which is fitted into the belt-shaped body wa to hold the belt-shaped body wa at a predetermined position, and the positioning portions 13A are urged to a protruding state shown in the drawing, and are mutually fitted by pressing from above. It is formed by a plurality of elastic members 13 a housed in the lower mold 13 by contracting. Further, at least one of the lower mold 13 and the upper mold 14 is heated by a heating device (not shown), and is configured to heat and plasticize the belt-shaped body wa held by the positioning portion 13A.

The band wa is fitted and mounted on the positioning portion 13A of the press device 12 thus configured, and the lower mold 13 to the upper mold 14 are heated. Therefore, the upper mold 14 is lowered while heating the band wa. Then, the positioning portion 13A is contracted as the upper mold 14 descends to make the belt-like body wa flat , thereby obtaining the flat plate-shaped material 1. The flat material 1 is easily processed by heating, and is plasticized to maintain a flat shape.

As another pressing device 15 for forming the band-shaped body wa into a flat plate shape, as shown in FIG. 4, a lower mold 16 on which the band-shaped body wa is placed, an upper mold 17 which comes into contact with and separates from the lower mold 16, and Means 18 for separating both ends wb of strip wa from each other and lower mold 1
6. At least one of the upper molds 17 has a heating means (not shown).

The belt-shaped body wa is placed on the lower die 16 of the press device 15 having the above-described configuration, and the lower die 16 to the upper die 17 are placed.
The upper mold 17 is lowered while the both ends wb of the strip wa are separated from each other by means 18 for heating the strip wa and separating the strip wa by the means 18 for separating the strip wa. Get 1.

In the press units 12 and 15, the strip wa was heated by heating the mold.
It is also possible to heat the belt-like body wa by other means such as hot air.

Next, the roll rolling processing step c for peeling the coating film 2 from the strip-shaped plate-like material 1 obtained in the pre-processing step b will be described.

As shown in FIG. 1, the roll device 19 used in the roll rolling process step c is made of metal which is disposed to face each other, and has a mirror-finished outer peripheral surface or a chrome-plated resin material side. Roll 20 and coating side roll 2
One.

The resin material side roll 20 and the coating film side roll 21
That is , the rotation is driven so that the peripheral speed of the coating film-side roll 21 pressed against the surface of the coating film 2 becomes higher than the peripheral speed of the resin material-side roll 20 pressed against the surface of the resin material 3.

Accordingly, the flat material 1 supplied between the resin material side roll 20 and the coating film side roll 21 is composed of the two rolls 20,
Rolls 21 and 21
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. 5A and the side view of FIG.
The vicinity 20a of the zero edge is tapered so that the diameter increases as the edge 20b moves, and the diameter 20d at the edge 20b is formed larger than the diameter 20c at the center.

Similarly, as shown in the front view in FIG. 5 (a) and the side view in FIG. 5 (b), the roll 21 on the coating film side becomes larger as the edge 21a near the edge of the roll 21 shifts to the edge 21b. The rolls 20 and 21 have a tapered shape, and the center portions of both side edges of the flat sheet material 1 protrude outward and are deformed by the rolling of the rolls 20 and 21.
a, 21a are formed in a tapered shape having a larger diameter as they move to the edges 20b, 21b.
And 21a, the pressure between the two rolls 20 and 21 is ensured at both ends of the flat material 1, so that sufficient shear shear stress acts on both ends of the flat material 1 to apply the coating. Peeling of the film 2 is achieved.

It should be noted that one of the resin material side roll 20 and the coating film side roll 21 near one roller edge 20a or 21a
It is also possible to form only the taper shape whose diameter increases as it moves to the edge.

Reference numeral 22 in FIG. 1 denotes a brush, a scraper, or the like that scrapes the coating film 2 attached to the surface of the roll 21 by slidingly contacting the outer peripheral surface of the coating film side roll 21.

FIG. 6 is an explanatory view showing another embodiment of the roll device 19. The same reference numerals are given to the portions corresponding to those in FIG. Is coated with an elastic member, for example, a rubber 21e, thereby increasing the friction coefficient between the coating film-side roll 21 and the coating film 2 of the plate-shaped material 1, and is applied between the resin material 3 and the coating film 2. It has a function to secure the shearing force to improve the peeling of the coating film 2 and to prevent the coating film 2 from adhering to the coating film-side roll 21 due to the deformation of the rubber 21e caused by the pressing on the flat material 1. In addition, it is intended to improve the workability by facilitating biting when supplying the flat material 1.

FIG. 7 is an explanatory view showing another embodiment of the roll device 19, in which the same reference numerals are given to the portions corresponding to those in FIG. 21 and the resin material 3 at the downstream position of the resin material side roll 20.
And a pair of transport rolls 22 that sandwich and transport the coating film 2,
23, and an adhesive tape supply reel 24 facing the other one of the transfer rollers 22 and an adhesive tape collection reel 25 for winding the adhesive tape 26 fed from the adhesive tape supply reel 24 are disposed. The adhesive tape 26 fed from the feeding reel 24 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 adhering 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 material 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 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.

[0044]

According to the method for recycling a coated resin product according to the present invention described above, in order to easily supply a coated resin product to a roll device, a complicated shape is formed by pressing. Even if it is a painted resin product, it easily becomes almost flat, and this flat material is rolled by a roll device having a coating side roll and a resin material side roll having different rotational peripheral speeds, and a resin material and a coating film are formed. Since the coating film is peeled off from the resin material by applying shear shear stress during the application, the coating film is separated by applying a shear shear stress between the coating film and the resin material by a roll device without grinding and heating. It is possible to obtain high quality recycled resin products with extremely high coating film removal efficiency, with excellent productivity and at low cost. Without, excellent environmental safety, and have equal present invention unique effect excellent in processing capability, in which a large made to contribute to the recycling of painted resin products of wide areas.

[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 pretreatment step.

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

FIG. 6 is also an explanatory view of a roll rolling processing step.

FIG. 7 is an explanatory view of a roll rolling process step.

FIG. 8 is a schematic explanatory view of a conventional coating film peeling apparatus.

FIG. 9 is a sectional view taken along line AA in FIG.

[Explanation of symbols]

 a resin product recovery step b pre-treatment step c roll rolling step d pulverization step e pelletizing step f forming step w bumper 1 plate-shaped material 2 coating film 3 resin material 4 pulverized material 5 pellet 10 support member 12 press device 13 lower Mold 14 Upper mold 15 Press device 16 Lower mold 17 Upper mold 18 Separating means 20 Resin material side roll 21 Coating side roll 21e Rubber 22 Transport roll 23 Transport roll 26 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 (8)

(57) [Claims] 1. A pretreatment step of processing a coated resin product into a substantially flat plate shape by a press device, and a coating film side roll and a resin material provided opposite to each other with respect to the flat plate material obtained in the pretreatment step. Side roll, the peripheral speed of the coating film side roll
Rolling by a roll device whose degree is larger than the peripheral speed of the resin material side roll , and applying a shear shear stress between the resin material and the coating film to separate the coating film from the resin material, A pulverizing step of pulverizing the resin material from which the coating film has been peeled off in the rolling step to obtain a pulverized material. 2. The method for recycling a coated resin product according to claim 1, wherein the resin product is heated by heating a mold of a press device for processing the resin product into a flat plate shape. 3. The method for recycling a coated resin product according to claim 1, wherein the pressing device has means for separating both ends of the resin product. 4. The taper according to claim 1, wherein at least one of the coating film side roll and the resin material side roll of the roll device has a tapered shape in which the vicinity of the roll edge increases in diameter toward the edge direction. How to recycle one painted resin product. 5. The method for recycling a coated resin product according to claim 1, wherein the outer periphery of the coating film side roll is covered with an elastic member. 6. A roll device having a pair of transport rolls for nipping and transporting a resin material and a coating film at a downstream position of the coating material side roll and the resin material side roll which are disposed opposite to each other, and one of the transport rollers. The method for recycling a coated resin product according to any one of claims 1 to 5, wherein the roll is pressure-contacted with an adhesive tape fed from an adhesive tape feeding reel to the coated film to recover the coated film. 7. The method according to claim 1, further comprising a step of heating and melting the pulverized material obtained by pulverizing in the pulverizing treatment step, and filtering and removing the remaining coating film pieces by a screen mesh to form a pellet. How to recycle any one of the painted resin products. 8. The method according to claim 1, wherein the pulverized material obtained by the pulverization in the pulverization step is separated into a portion constituting the resin material and a portion constituting the coating film by a separation device. How to recycle one painted resin product.