JPH07256643A - Method for recycling coated resin product - Google Patents

Abstract

PURPOSE:To provide a method for recycling a coated resin product in which removal efficiency of a paint film, environmental safety and treatment capacity are excellent and a high-quality recycled resin product is obtained. CONSTITUTION:A coated resin product W is cut into several divisions and worked. The cut material 1 is rolled by a roll device 12 equipped with a roll 14 in the paint film side and a roll 13 in the resin material side. In the rolls 13, 14, the circumferential velocities of rotation are different. The rolls 13, 14 are formed into a taper shape, so that the vicinity of an edge becomes large diameter in accordance with transfer to the edge. Further a paint film 2 is peeled from the resin material by adding shearing stress between the resin material 3 and the paint film 2.

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 resin products such as bumpers and side moldings used as functional parts for decoration and cushioning of automobiles.

[0002]

2. Description of the Related Art In recent years, the recycling of resin products has been called for due to the growing concern about environmental problems and the reuse of resources. For example, in the process that occurs when manufacturing resin products such as bumpers and side moldings in the field of automobile industry. Attention has been paid to the recycling of resin products that are separated and collected from defective products and scrapped vehicles.

In many cases, resin products such as bumpers and side moldings are coated on the surface of the products to improve appearance and quality. For example, the skin of the bumper is made of a thermoplastic resin material such as polypropylene resin. A coating film is formed on the top. This coating film is a thermosetting resin such as aminopolyester type, aminoacrylic type, polyesterurethane type,
Although these are acrylic urethane type resins and these resins are in liquid state before the curing reaction, a crosslinked structure is imparted by the baking coating process. Because of its strong and dense structure, the painted resin bumper has excellent chemical resistance, heat resistance, abrasion resistance, weather resistance and surface gloss.

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

Further, since there is almost no interaction between the coating film piece and the polypropylene resin as the base resin, the coating film piece prevents the kneading and integration in the recycled resin, and the mechanical properties of the resin product. Is significantly reduced.

For this reason, when recycling a resin product that has been subjected to coating treatment, it is necessary to remove the coating film.

[0007] As a method for removing the coating film, automobile technology Vol. 46. No. 5,
1992. Mechanical, as disclosed on pages 3-9,
It is classified into physical and chemical methods.

[0008] The mechanical coating film removing method is, for example, a shot in which compressed air is used to spray a fine-particle abrasive on the surface of a coating film formed on a resin product to destroy and remove the coating film and deposits. 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 removes the coating film by friction, impact, etc., so that it is excellent in toxicity and environmental safety, but on the other hand, it requires a long processing time and the coating film removal efficiency is not sufficient. It is difficult to process. The screen mesh method is excellent in toxicity and environmental safety because it removes coating film fragments by filtration, but clogging of the screen mesh occurs, the extrusion pressure remarkably increases, the extrusion rate decreases, and the production rate declines. The removal efficiency of the membrane 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 of the screen mesh.

The physical coating film removing method uses a halogen-based solvent or various organic solvents, and removes the coating film by utilizing the solvent penetration into the interface between the coating film and the material and the swelling phenomenon of the coating film by the solvent. However, it is inferior in environmental safety, has relatively low coating film removal efficiency and processing capacity, and may deteriorate the material.

Since these mechanical and physical coating film removal methods have low coating film removal efficiency, the resin products using the recycled resin materials obtained by these methods are preferable in terms of product appearance and mechanical properties. However, the application range is greatly limited.

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

This method has problems in secondary treatment such as wastewater treatment, and also has a low treatment efficiency and is not efficient.

An apparatus for removing the coating film of a resin product is disclosed in Japanese Unexamined Patent Publication (Kokai) No. 5-337941, and a synthetic resin showing a front explanatory view in FIG. 7 and a sectional view taken along line AA in FIG. 8 is shown. Surface stripping devices have been proposed.

In this peeling apparatus, a pair of conveying rollers 21 convey a resin product, for example, a side molding 22, between rotating bodies 23 and 24 made of a foaming synthetic resin, and a conveying speed V of the side molding 22 is changed to a rotating body. By setting the rotational peripheral speeds of 23 and 24 to be slower, the coating 22a of the side molding 22 and the double-sided tape 22b are subjected to cutting and high frictional force, and the coating 22a of the surface of the side molding 22 is applied.
Also, the double-sided tape 22b is cut and peeled off, and the side molding 22 is discharged to the outside by the pair of conveying rollers 21.

This apparatus is not preferable in the working environment because the rotating body is brittlely broken by contacting the resin product with the rotating foaming synthetic resin to the rotating bodies 23 and 24, and dust is generated. There is a problem that it is not suitable for curved resin products.

[0017]

SUMMARY OF THE INVENTION Therefore, 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 which is excellent in coating film removal efficiency, environmental safety and treatment capacity. To provide a method.

[0018]

A method for recycling a coated resin product according to the present invention which achieves the above object is obtained by a pretreatment step of cutting a coated resin product into several pieces and a pretreatment step. And a coating material-side roll and a resin material-side roll having different rotational peripheral speeds, which are arranged opposite to each other, and the vicinity of the edge of at least one of the coating-material-side roll and the resin-material-side roll is , A roll rolling treatment step of rolling by a roll device having a taper shape whose diameter becomes larger as it moves to the edge, and peeling the coating film from the resin material by applying shear shear stress between the resin material and the coating film. And a crushing process for crushing the resin material from which the coating film has been peeled in the roll rolling process to obtain a crushed material.

[0019]

EXAMPLE A method for recycling a coated resin product according to the present invention will be described below by taking as an example the 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 the method for recycling a coated resin product in the present embodiment. In-process defective products that are generated during the production and assembly of a resin bumper,
A resin product collecting step a for separating and collecting from a scrap car, a pretreatment step b for cutting the collected resin bumper into a flat plate shape or a vertical split shape into several divisions, and a roll made from the cutting material obtained in the pretreatment step b Roll-rolling treatment step c for peeling the coating film by rolling with an apparatus, crushing treatment step d for crushing the resin material from which the coating film is peeled off, and pelletizing step e for pelletizing the crushed material obtained in the crushing treatment step d. And a molding step f in which the pellet obtained in the pelletizing step e is used as a material to manufacture the product.

Next, each step will be described in sequence. The reference numeral w shown in FIG. 1 in the resin product collecting step a is a painted resin bumper that is removed from defective products in the process, scrapped vehicles, etc., and collected to remove metal parts. This bumper w is a thermoplastic resin such as polypropylene resin. It is a coated resin product in which a coating film of a thermosetting resin such as aminopolyester-based, aminoacrylic-based, polyesterurethane-based, acrylicurethane-based resin is formed on a resin material made of.

The bumper w recovered in the resin product recovering step a and having the metal parts removed therefrom has a flat plate shape in order to improve the removal efficiency of the coating film in the next roll rolling processing step c in the pretreatment step b. Alternatively, it is cut into vertical pieces. This processing is performed, for example, by cutting into relatively flat plate-shaped portions wa such as the upper surface portion, the front surface portion, and the side surface portion which do not include protrusions such as ribs shown by diagonal lines wa in FIG. Then, the strip-shaped flat plate-shaped material 1a may be obtained, or a plurality of vertically split material 1a 'may be obtained by cutting as shown by wa' in FIG. 2 (b).

In order to obtain the cutting material 1 from the bumper w, as shown in the cross-sectional perspective view of the main part in FIG. 3, the cutting member 1 is held by a support member 10 which engages and holds the bumper w at a predetermined position. It can be easily obtained by cutting the bumper w with the cutter 11 in this state.

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

As shown in FIG. 1, the roll device 12 used in the roll-rolling treatment step c is made of metal arranged opposite to each other, and has a resin material side whose outer peripheral surface is mirror-finished or chrome-plated. Roll 13 and coating side roll 1
Have four.

Roll 13 for resin material and roll 14 for coating film
So that the respective peripheral velocities are different from each other, for example, the peripheral velocity of the coating film side roll 14 that is in pressure contact with the surface of the coating film 2 is higher than the peripheral velocity of the resin material side roll 13 that is in pressure contact with the surface of the resin material 3. Is driven to rotate.

Therefore, the flat plate material 1 supplied between the resin material side roll 13 and the coating film side roll 14 is
Rolled by pressing force of 14 and rolls 13, 14
A shear shear stress is applied between the resin material 3 and the coating film 2 based on the relative difference in peripheral speed between the resin material 3 and the coating material 2, and the coating film 2 is separated from the resin material 3.

As shown in the front view of FIG. 4A and the side view of FIG.
The vicinity 13a of the third edge 13a has a taper shape whose diameter increases as it moves to the edge 13b, and the diameter 13d at the edge 13b is larger than the diameter 13c at the central portion.

Similarly, as shown in the front view of FIG. 4 (a) and the side view of FIG. 4 (b), the coating film-side roll 14 becomes larger as the portion 14a near the edge of the roll 14 moves to the edge 14b. By the rolling between the rolls 13 and 14 having a diameter, the central portions on both side ends of the flat plate-shaped material 1 squeeze outward and are deformed. , 14a are formed in a tapered shape whose diameter increases as they move to the edges 13b, 14b, so that the gap between the edges 13a and 14a near the edges of both rolls 13, 14 for pressing the both ends of the cutting material 1 is reduced. It becomes small, and sufficient pressing force by both rolls 13 and 14 is secured even at both side ends of the flat plate material 1. Therefore, sufficient shear shear stress acts at both ends of the flat plate material to achieve peeling of the coating film 2. To be done.

Incidentally, one of the resin material side roll 13 and the coating side roll 14 is near the roller end edge 13a or 14a.
It is also possible to form only the taper so that the diameter increases as it moves to the edge.

Reference numeral 15 in FIG. 1 denotes a brush, a scraper or the like which scrapes off the coating film 2 which is in sliding contact with the outer peripheral surface of the coating film side roll 14 and adheres to the surface of the roll 14.

FIG. 5 is an explanatory view showing another embodiment of the roll device 12, and although detailed description is omitted by assigning the same reference numerals to the parts corresponding to those in FIG. Is coated with an elastic member such as rubber 14e to increase the friction coefficient between the coating film side roll 14 and the coating film 2 of the flat plate-shaped material 1, and to add between the resin material 3 and the coating film 2. It has a function of ensuring shear shear stress to improve the peeling of the coating film 2 and preventing the coating film 2 from adhering to the coating film side roll 14 due to the deformation of the rubber 14e caused by the pressing against the cutting material 1. In addition, the workability is improved by facilitating the biting when the cutting material 1 is supplied.

FIG. 6 is an explanatory view showing another embodiment of the roll device 12, and although the detailed description is omitted by assigning the same reference numerals to the parts corresponding to those in FIG. 14 and the resin material 3 at the downstream position of the resin material side roll 13.
And a pair of transport rolls 16 for gripping and transporting the coating film 2,
17 is provided, and an adhesive tape feeding reel 18 that opposes the one conveying roll 16 is provided, and an adhesive tape collecting reel 19 that winds the adhesive tape 20 fed from the adhesive tape feeding reel 18 is arranged. The adhesive tape 20 fed from the feeding reel 18 by the coating film 2
A coating film recovery means is provided for pressing and contacting the coating film 2 for adhesive recovery of the coating film 2.

As means for removing the peeled coating film 2 adhering to the resin material 3 from the resin material 3, an 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 treatment step c, and the rolled resin material 3 is pulverized by a shredder or the like in the next pulverization treatment step d to become a pulverized material 4.

The pulverized material 4 is supplied to the extruder in the subsequent pelletizing step e. The extruder is, for example, a crushed material 4 charged into a hopper, which is advanced in the barrel by rotation of a screw and heated by a band heater or the like, melted while being advanced in the barrel, and extruded from a 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.

The pellets 5 obtained in the pelletizing step e are added with pellets made of a resin such as virgin polypropylene, if necessary, in the next molding step f to become resin products such as bumpers again.

In the above embodiment, the crushed material 5 made of the resin material crushed in the crushing step d is pelletized in the step e.
When the film was heated and melted in Pellets to remove the remaining coating film pieces with a screen mesh, the pulverized material obtained in the pulverization process e was separated by a pin mill or a specific gravity separator instead of the pelletization process e. It is also possible to separate the part that made up the resin material and the part that made up the coating film in the equipment, and it is possible to reduce the man-hours such as melting and extrusion and the cost compared to pelletizing. It is possible.

[0039]

According to the method for recycling a coated resin product according to the present invention described above, the coated resin product is cut into a proper size in several parts in order to facilitate the supply to the roll device. Processed, this cutting material is a taper shape whose diameter becomes larger as the vicinity of the edge moves to the edge, and is rolled by a roll device equipped with a coating side roll and a resin material side roll having different rotational peripheral speeds, And since the coating film is peeled from the resin material by applying shear shear stress between the resin material and the coating film, a coating film over the entire surface including the side edge of the flat plate material is crushed and heated without rolling. The coating film can be separated by applying shear shear stress between it and the resin material, and it is possible to obtain a high-quality recycled resin product with extremely high coating film removal efficiency with excellent productivity and at low cost. Compared with other coating removal methods Since it does not require the use of a solvent, etc., it has no toxicity, is excellent in environmental safety, has excellent processing ability, etc. and has unique effects of the present invention, which greatly contributes to the recycling of coating resin products in a wide range of fields. Is.

[Brief description of drawings]

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

FIG. 2 is likewise an explanatory view of a pretreatment step in the method for recycling coated resin products in this example.

FIG. 3 is likewise an explanatory diagram of a pretreatment process.

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

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

FIG. 6 is likewise an explanatory diagram of a roll rolling process step.

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

8 is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

 a resin product collecting step b pretreatment step c roll rolling processing step d crushing processing step e pelletizing step f molding step w bumper wa, wa 'plate-shaped portion 1 cutting material 2 coating film 3 resin material 4 crushing material 5 pellets 10 support Member 11 Cutter 12 Roll device 13 Resin material side roll 14 Coating film side roll 14a Rubber 16 Conveying roll 17 Conveying roll 20 Adhesive tape

Claims (8)

[Claims] 1. A pretreatment step of cutting a coated resin product into several divisions, and a coating material side roll having different rotational peripheral speeds in which cutting materials obtained in the pretreatment step are arranged to face each other. And the roll near the edge of at least one of the roll on the coating material side and the roll on the resin material side, and a roll device having a taper shape that becomes larger in diameter as it moves to the edge. In addition, a roll rolling process that applies shear shear stress between the resin material and the coating film to peel the coating film from the resin material, and the resin material from which the coating film has been peeled in the roll rolling processing process is crushed to obtain a pulverized material. A method for recycling a coated resin product, comprising: 2. The method for recycling a coated resin product according to claim 1, wherein in the pretreatment step, the resin product is cut into relatively flat plate-shaped portions to obtain a cut material. 3. The method for recycling a coated resin product according to claim 1, wherein the resin product is engaged with and held by a support member and cut with a cutter to obtain a cut material. 4. The method for recycling a coated resin product according to claim 1, wherein the cutting material is a strip. 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 has a pair of transport rolls for sandwiching and transporting the resin material and the coating film at a position downstream of the coating film side roll and the resin material side roll, which are arranged to face each other, and one of the transporting rolls. The method for recycling a coated resin product according to any one of claims 1 to 5, wherein the roll is brought into pressure contact with an adhesive tape fed from an adhesive tape feeding reel to collect the coated film. 7. A pelletizing step of heating and melting a pulverized material obtained by pulverizing in a pulverizing step, and filtering out remaining coating film pieces by a screen mesh to form a pellet. Any one of the methods for recycling coated resin products. 8. The crushed material obtained by crushing in the crushing process is separated by a separator into a part that constitutes a resin material and a part that constitutes a coating film. One method for recycling coated resin products.