JPH07331138A - Method and apparatus for removing coating film from resin article - Google Patents

Abstract

PURPOSE:To efficiently remove a coating film from a coated resin article by immersing the article in a removing fluid mainly comprising an org. solvent, an acid, and an alcohol. CONSTITUTION:A coating film is removed from a coated resin article by immersing the article in a removing fluid mainly comprising an org. solvent, an acid, and an alcohol. When the article is one prepd. by applying a repairing putty to the surface of a resin substrate and then coating the surface with a coating material, the putty is also removed together with the coating film. This method is applicable to resin parts made from an ABS resin, an ACS resin, polyacetal, polystryene, etc., for office automation machines such as a word processor, a personal computer, a computer, a copying machine, etc. Formerly, these machines have problems with resin recycling caused by fingerprints or dirt attached by static electricity.

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 resin product.

[0002]

2. Description of the Related Art In recent years, the reuse of waste materials has been sought after due to problems such as exhaustion of resources and energy and environmental destruction due to industrial waste, and the automobile industry is no exception. In particular, resin products using plastics take a long time to decompose in a natural environment, while they are easy to melt and re-mold.
There are great expectations for recycling. In general,
Plastic molded products are reused by crushing and granulating the molded products to make recycled pellets and molding them again. At that time, if the molded product is painted, or if the molded product is filled with repair putty and painted, if it is melted and molded as it is, the coating film component and the putty component will be contained in the resin. Are mixed. As a result, because the intermolecular bond of the resin material is inhibited, the impact resistance, bending strength, tensile strength, low temperature resistance, etc. of the molded product deteriorate,
There was a problem that the standard required as a product could not be satisfied and it was not suitable for the original application.

Therefore, in order to reuse the coated resin product, it is necessary to remove the coating film from the resin product, and a method such as dipping in a commercially available stripping solution has been used. However, in the case where a large amount of paint is applied, such as a bumper of an automobile, such a method cannot completely remove the coating film.

Therefore, as a method for peeling the coating film, a method of peeling the coating film by heating a coating material obtained by roughly crushing a polypropylene resin molded product in water and methylene chloride to about 40 ° C. (Kaihei 5-84746), a method of peeling a coating film by sealing a resin molded article having a coating film in a container containing ethanol heated to a temperature below the boiling point (Japanese Patent Laid-Open No. 5-228432).
However, none of them was able to completely and efficiently remove the coating film.

[0005]

From the above viewpoint, a method of peeling a coating film on a resin product by utilizing a synergistic action with a physical rubbing force in addition to a chemical / static peeling action is proposed. Proposed (JP-A-5-318999 and JP-A-5-189999)
No. 318484, Nikkan Kogyo Shimbun, February 8, 1994, etc.). However, the effect of removing the paint by the stripping solution itself is still insufficient, and since an alkali such as caustic soda is used for the stripping solution, there is a problem that the waste water treatment after the cost is expensive.

The present invention has been made from the above viewpoint, and it is an object of the present invention to provide a method and an apparatus capable of efficiently removing a coating film from a resin product by enhancing the removal effect of the removing liquid itself on the coating film. To do.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that a resin product having a coating film formed on the surface of a resin substrate is treated with an organic solvent, an acid and an alcohol. It was found that the coating film can be efficiently removed from the resin substrate by immersing it in the removal liquid containing the main component.
If the resin product is such that the resin base is filled with the repair putty and is coated, it was found that the repair putty together with the coating film can be efficiently removed from the resin base, and the present invention has been accomplished. .

That is, the present invention provides a method for removing a coating film from a resin product by immersing a resin product having a coating film formed on the surface of a resin substrate in the removal liquid, wherein the removal liquid is an organic solvent, an acid and A method for removing a coating film from a resin product, which comprises alcohol as a main component, wherein the resin product is a resin product in which a resin substrate is filled with repair putty and a coating film is formed on the surface thereof. In this case, a method for removing a coating film of a resin product is characterized in that the repair putty is removed together with the coating film from the resin substrate.

Further, according to the present invention, a crushed product of a resin product having a coating film formed on the surface thereof and a removing liquid or a cleaning liquid containing an organic solvent, an acid and an alcohol as a main component are contained and agitated. A stirring tank, a drying tank for drying the crushed material, and a crushed material conveying means for transferring the crushed material from the stirring tank to the drying tank, wherein the stirring tank is a crushed material for charging the crushed material. It has a charging port, a liquid injection port for injecting a removal liquid or a cleaning liquid, a drainage port for discharging the removal liquid or the cleaning liquid, and a pulverized product outlet for taking out a pulverized product from a tank, and stirring When the pulverized product is immersed in the removal liquid stored in the tank, the removal liquid is made to act, then the removal liquid is discharged, and the cleaning liquid is injected to wash the pulverized product, and at least when cleaning the pulverized product with the cleaning liquid. Apply from ground material by stirring in the tank. Removal of the further ground product is conveyed from the stirred tank to the drying vessel, to provide a film removal apparatus of the resin product characterized in that the cleaning solution remaining was be dried pulverized product.

The present invention will be described in detail below.

<1> Method of removing coating film of the present invention The method of removing coating film of the present invention is applied to all resins generally used for forming a substrate, and the kind of applicable resin is not particularly limited. Not, but especially polyethylene,
Polyolefin resin such as polypropylene and modified polypropylene, olefin thermoplastic elastomer, polystyrene, methacrylic resin, polyamide, polyacetal, polycarbonate, phenol resin, ionomer resin, ABS resin, ACS resin, AES resin, polyester resin such as PBT resin, PPO It is preferably applied to resins or polymer alloys composed of two or more of these resins.

Further, as a coating film to which the method for removing a coating film of a resin product of the present invention is applied, an acrylic resin, a melamine resin, an acrylic melamine resin, an alkyd melamine resin, a urethane which is usually formed on the surface of the resin for various purposes. Examples of the coating film include a resin, a phthalic acid resin, a lacquer enamel, a fluororesin, an epoxy resin, a crocon resin, a ketone resin, a xylene resin, and an aqueous paint emulsion paint. A paint usually used for coating a resin substrate contains components such as a pigment and a primer in addition to these main components, but the present invention is not affected by these components.

In the method for removing a coating film of a resin product according to the present invention, when the resin product is a resin product in which a resin substrate is filled with repair putty and a coating film is formed on the surface thereof, the coating is applied. The repair putty is removed along with the membrane.

Examples of such repair putty include polyester resin and epoxy resin which are usually used for repairing the above resin products. Specific examples of the resin product on which the above-mentioned coating film is formed include, for example, bumpers for automobiles in which various coating films such as urethane resin-based and melamine resin-based are applied to modified polypropylene and olefin-based thermoplastic elastomer. , Dashboard, fender, etc. All of these resin products are made of recyclable resins, and removal of the coating film and putty is one of the important steps in determining the quality of the recycled products in the process of recycling them.

The method for removing the coating film of the resin product of the present invention also comprises
OA for word processors, personal computers, computers, copiers, etc.
It can also be applied to a resin portion made of ABS resin, ACS resin, polyacetal, polystyrene or the like of a device. The dirt attached to these devices due to hand dust, static electricity, etc. has been a problem in regenerating the resin.

Next, a removing liquid used in the method for removing the coating film of the resin product of the present invention, the removing liquid is an organic solvent,
Mainly contains acid and alcohol. Examples of the organic solvent used for such a removing liquid include hydrocarbons such as pentane, hexane, benzene, toluene and xylene,
Methylene chloride, chloroform, dichloroethane, trichloroethylene, perchloroethylene, propyl chloride, butyl chloride, chloropentane, chlorobenzene, dichlorobenzene, butyl bromide, propyl bromide, ethyl bromide, methyl bromide, bromobenzene, dibromobenzene, etc. Halogenated hydrocarbons, ketones such as acetone, ethylmethylketone and cyclohexanone, ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane and anisole, esters such as ethyl acetate, butyl acetate and methyl propionate, ethylenediamine And amines such as pyridine and piperidine. Among these organic solvents, halogenated hydrocarbons are preferably used in the present invention, and chlorine-based organic solvents are more preferably used.

Examples of the acid used in the removing solution include organic acids such as formic acid, acetic acid and oxalic acid, hydrochloric acid,
Mineral acids such as sulfuric acid and nitric acid, sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, and the like are preferable, and among these, methanesulfonic acid is more preferably used.

As the alcohol used in the above removing solution, for example, methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol and the like can be preferably mentioned, and among these, methanol is further preferable. Are more preferably used.

Further, as a preferred combination of the organic solvent, the acid and the alcohol, which are the main components of the removing liquid of the present invention, the organic solvent is one or more selected from methylene chloride, trichlorethylene and perchlorethylene, Mention may be made of combinations in which the acid is methanesulphonic acid and the alcohol is methanol.

The amount of the organic solvent, the acid and the alcohol in the above-mentioned removing liquid depends on the resin substrate on which the coating film is formed and the type of the coating film to be removed, but the total amount of the removing liquid. In contrast, the organic solvent is approximately 80 to 95v
It is preferable that the ol%, the acid is approximately 1 to 10 vol%, and the alcohol is approximately 1 to 10 vol%.

For example, when an acrylic melamine resin-based coating film or an alkyd melamine resin-based coating film is applied to a polypropylene resin substrate, the compounding amount of each component in the removing liquid used is based on the total amount of the removing liquid. Organic solvent 85-90v
ol%, acid 3 to 10 vol%, alcohol 3 to 8 vol
% Is preferable.

When the resin substrate is coated with a urethane resin coating, the amount of each component in the removing liquid used is 75 to 85 vol of organic solvent based on the total amount of the removing liquid.
%, Acid 10 to 15 vol%, alcohol 5 to 10 vo
1% is preferred.

In addition to the above components, the removing liquid used in the present invention may optionally contain water, a surfactant and the like,
This is possible without impairing the gist of the present invention. In the method of removing a coating film of a resin product of the present invention, the coating film is removed from the resin product by immersing the resin product having the coating film formed on the surface of the resin substrate in the above removing solution.

When the method for removing the coating film of the resin product of the present invention is used to remove the coating film of, for example, an automobile bumper in which a urethane resin-based or acrylic melamine resin-based coating film is formed on a polypropylene resin substrate, the bumper is applied. The film is crushed to an appropriate size as it is (the obtained resin product pulverized product is simply referred to as "pulverized product" in the present specification), and the obtained pulverized product is put into the above-mentioned removal liquid. -24 hours, preferably 3-15 hours, more preferably 5-10.
Immerse for a period of time. The amount of the removing liquid used is not particularly limited, but is preferably 0.5 to 1.0 times, and more preferably about 0.75 times the volume of the pulverized material.

The temperature of the removing solution at the time of immersion may be room temperature or may be heated to a high temperature (about 30 to 100 ° C.). In this case, the immersion treatment at a high temperature shortens the processing time. It becomes possible. Further, if the stirring is performed in addition to the dipping, the dissolution of the coating film is promoted and the coating film adhering to the substrate can be easily peeled off, so that the processing time can be shortened. The immersion time required to remove the coating film is affected by the thickness of the coating film, the size of the pulverized product, the type of coating film, etc., so the immersion time should be adjusted appropriately in each case. Is preferred.

After a dipping treatment sufficient to remove the coating film, the pulverized product is taken out of the removing liquid and put in a washing liquid to carry out a washing treatment for about 0.1 to 1 hour. Then, this is taken out from the cleaning liquid and dried to obtain a pulverized product from which the coating film is sufficiently removed. Further, if the stirring is performed during the cleaning, the cleaning processing time can be shortened. When stirring is performed during cleaning, the coating film can be efficiently removed without stirring during immersion.

The treatment of washing the pulverized product with a cleaning liquid is essentially carried out to remove the acidic components contained in the coating film removing agent from the pulverized product, but the cleaning liquid used in the present invention removes the acidic component. It is preferable to adjust the washing solution to be basic so as to neutralize the acid contained in the solution. A volatile solvent may be used to shorten the drying time.
Examples of such a cleaning liquid include methylene chloride, trichloroethylene, perchlorethylene, isopropyl alcohol, methanol and the like, which have been adjusted to a pH of 7 to 12 with amines or organic acids such as citric acid. In addition, the cleaning treatment may be performed using a highly volatile solvent after performing the cleaning treatment with an aqueous neutralizing agent.

Also in the case where the resin product is a resin substrate filled with repair putty and a coating film is formed on the surface thereof, both the coating film and the putty are removed from the resin substrate by the same treatment as described above. Can be removed.

<2> Coating Film Removing Apparatus of the Present Invention The coating film removing apparatus of the present invention is an apparatus for efficiently removing the coating film of the above resin product, and is used for the resin product having a coating film formed on its surface. A stirring tank for accommodating the crushed product and the above-mentioned removal liquid or cleaning liquid and stirring them, a drying tank for drying the crushed product, and a crushed product conveying means for transferring the crushed product from the stirring tank to the drying tank. In addition, the agitation tank is provided with a pulverized material input port for inputting a pulverized product of a resin product having a coating film formed on the surface thereof, a liquid injection port for injecting a removal liquid or a cleaning liquid, and It has a drainage port for discharging the liquid or the cleaning liquid, and a crushed material outlet for taking out the crushed material from the tank (FIG. 1).

A coating film removing apparatus for a resin product having a coating film formed on its surface will be described below. In the above resin product, a coating film is formed on the surface of a resin substrate filled with repair putty. However, the following apparatus operates similarly, and in this case, the repair putty is removed from the resin base together with the coating film.

In the coating film removing apparatus of the present invention, the removing liquid is caused to act by immersing the pulverized product of the resin product having the coating film formed on the surface thereof in the removing liquid contained in the stirring tank, and further if necessary. By removing the coating film from the crushed product by stirring the inside of the tank accordingly, after discharging the removing liquid, by injecting a cleaning liquid to wash away the removing liquid from the crushed product, by stirring inside the tank at the time of cleaning The remaining coating film is removed from the pulverized product, and the pulverized product is conveyed from the stirring tank to the drying tank to dry the cleaning liquid remaining on the pulverized product.

Further, as shown in FIG. 2, a pulverized material input port for inputting a pulverized material of a resin product having a coating film formed on the surface thereof and a removing liquid to the coating film removing apparatus (FIG. 1). It has a pouring port for injecting, a drainage port for discharging the removal liquid, and a crushed product outlet for taking out the crushed product from the tank, and the crushed product is immersed in the removal liquid stored inside. A resin product having a coating film formed on the surface in the immersion tank, by adding a dipping tank for allowing the dipping tank and a second pulverized material conveying means for conveying the pulverized material from the dipping tank to the stirring tank. After immersing the pulverized product of No. 2 in the removal liquid, convey the pulverized product to a stirring tank, and wash the pulverized product with the cleaning liquid in the stirring tank and stir the inside of the tank, from the viewpoint of productivity. It is more preferable.

Even when such an apparatus is used, the processing steps after the stirring tank are the same as those of the coating film removing apparatus. In the above process, before injecting the cleaning liquid into the stirring tank and cleaning the removal liquid attached to the pulverized material, if necessary,
It is also possible to add a step of injecting the removal liquid into the stirring tank and stirring the mixture together with the pulverized material.

Here, the charging port for charging the pulverized product of the resin product having the coating film formed on its surface into the coating film removing apparatus of the present invention is
In the case of a device with a dipping tank, the crushed material feed port of the dipping tank is used, and in the device without a dipping tank, the crushed material feed port of the stirring tank is used. It is also possible to connect them.

Further, in the coating film removing device (FIG. 2), a plurality of sets of crushed material conveying means for conveying crushed material from the immersion tank to the stirring tank are provided, and the crushed material is removed in a certain immersion tank. During the immersion in the liquid, the crushed product is sequentially transferred from another immersion tank, which has been immersed for a preset time or longer, to the stirring tank and the drying tank, and the cleaning treatment and the drying treatment are performed. On the other hand, the untreated pulverized product is newly put into the dipping tank from which the pulverized product has been taken out, and the dipping with the removing liquid is started. In this way, it is even more preferable from the viewpoint of productivity that the apparatus is capable of continuously performing a series of operations.

In the coating film removing apparatus of the present invention, the stirring means of the stirring tank has two or more stirring shafts provided with a plurality of stirring blades, and the stirring blades of each stirring shaft are alternately positioned. In addition, if the stirring means is such that the rotation directions of the respective stirring shafts can be set independently, it is possible to efficiently remove the deposits such as the coating film residue and the removal liquid from the pulverized product after the immersion treatment. It is preferable because it can be obtained.

Further, as shown in FIG. 2, the drying tank of the coating film removing apparatus of the present invention is provided with a crushed material charging port for charging a crushed material, a blower port for blowing hot air into the tank, and an exhaust gas. For discharging the pulverized material from the tank, an exhaust port for removing the pulverized material from the tank, a baffle plate provided in the tank, and a vibration generator for vibrating at least the baffle plate, and blowing air to the drying tank. A hot air generator for generating hot air
If it is connected to a condenser for liquefying the exhaust gas discharged from the drying tank exhaust port, the pulverized material injected from the upper inlet of the drying tank is rolled by the hot air while rolling the baffle from the upper tank to the lower tank. A system to be dried can be obtained, and the cleaning liquid vaporized by hot air can be liquefied and reused in a condenser, which is preferable in terms of working efficiency and working environment.

Here, as the conveying means for conveying the pulverized material from the stirring tank to the drying tank, a conveying means capable of adjusting the conveying speed, such as a spring feeder, is preferably used. Further, although a pulverized material conveying means is attached to the pulverized material taking-out port of the drying tank as required, the conveying means may be the same as described above.

In the above-mentioned drying tank, the vibration generator may be a device which is attached to each of the baffles provided in the drying tank so as not to hinder the passage of the pulverized material and vibrates only the baffles. A device that is attached to the drying tank and vibrates the entire tank including the baffle plate may be used. Also,
If the hot air blower is installed in the lower part of the drying tank and the exhaust port is installed in the upper part of the drying tank so that the hot air being sent flows from the lower part of the tank to the upper part of the tank, it will roll from the upper part of the tank to the lower part of the tank. Hot air efficiently hits the object, and a preferable drying condition can be obtained.

Although not shown, the coating film removing apparatus of the present invention may be provided with a reserve tank for a liquid such as a removing liquid or a cleaning liquid used in the coating film removing method of the present invention. In this case, in each reserve tank, the liquid used in the coating film removal method of the present invention is respectively stored, and the transfer means to the injection port of the tank in which the liquid is used, for example, a pump and a filtration means, For example, it is preferable that the structure is such that the liquid is connected via a transfer pipe having a filter or the like, and further, the liquid is connected to a drainage port of a tank in which the liquid is used via a transfer pipe having a transfer means.

Further, a condenser is connected to the drying tank,
In the case of an apparatus having a system for liquefying and recovering exhaust gas generated during drying, the recovered liquid will be transferred to a reserve tank for the liquid.

By using a filter, a reserve tank, a condenser and the like as described above, liquids such as a removing liquid and a cleaning liquid can be circulated and reused, which is preferable in terms of economy and working environment.

[0043]

In the method for removing a coating film of a resin product of the present invention, a removing solution containing an organic solvent, an acid and an alcohol as a main component is used, and a resin product having a coating film formed on the surface thereof is immersed in the removing liquid.
At this time, the coating film is dissolved and removed by the excellent coating film removing action of the above removing liquid. Furthermore, if the resin product is a resin product in which a resin substrate is filled with repairing putty and a coating film is formed on the surface thereof, it is possible to dissolve and remove the putty in addition to the coating film by dipping in the removal liquid. It is possible.

In the coating film removing apparatus of the present invention, a conveying means is used, if necessary, so that a coating film is formed on the surface from the crushed material charging port of the stirring tank or the crushed material charging port of the dipping tank in an apparatus having an immersion tank. The formed pulverized resin product is put into a stirring tank or a dipping tank. In addition, a removing solution containing an organic solvent, an acid and an alcohol as a main component is injected into the stirring tank or the dipping tank from the injection port, and the pulverized product of the resin product having the coating film formed on the surface is immersed in the removing solution. Thereby actuating the removal liquid.

After that, the removal liquid was discharged from the drainage port, and when the removal liquid was immersed in the immersion tank, the crushed material was conveyed to the stirring tank,
When immersed in a stirring tank, the crushed material does not move and the cleaning liquid is poured into the stirring tank to wash away the removal liquid on the crushed material, and the inside of the tank is stirred when the crushed material is washed with the cleaning solution. To remove the coating film from the ground material. Also,
Before injecting the cleaning liquid into the stirring tank to wash the removal liquid adhering to the pulverized material, if necessary, it is possible to add a step of injecting the removal liquid into the stirring tank and stirring with the pulverized material. . In this case, in an apparatus having no dipping tank, it is possible to continuously perform dipping and stirring with the removing liquid in the stirring tank.

The stirring means of this stirring tank has two or more stirring shafts provided with a plurality of stirring blades, and the stirring blades of the respective stirring shafts are arranged so as to alternate with each other. If the stirring means is such that the rotation direction of the shaft can be set independently, sufficient rubbing on the surface of the crushed product will be carried out when removing coating residue, removal liquid and other deposits from the crushed product after the immersion treatment. Power can be applied and efficient removal is possible.

After washing the crushed material with the above-mentioned washing liquid, the washing liquid is discharged from the drainage port of the stirring tank, and the remaining crushed material is conveyed from the stirring tank to the drying tank by the crushed material transferring means and remains in the crushed material in the drying tank. Dry the wash solution thoroughly.

The drying tank of the coating film removing apparatus of the present invention is of a hot air drying type, and the pulverized material charged from the upper charging port of the tank is transferred from the upper tank to the lower tank on a vibrating baffle provided inside. If it is a system that operates and is dried by hot air flowing from the lower part of the tank to the upper part of the tank, efficient drying is performed, and the cleaning liquid vaporized by the hot air can be liquefied and reused in the condenser. It is preferable in terms of work efficiency and work environment.

As described above, the apparatus for removing a coating film of a resin product of the present invention is applied by immersing a pulverized product of a resin product having a coating film formed on the surface thereof in a removing solution containing an organic solvent, an acid and an alcohol as main components. By swelling and dissolving the film and then stirring it, the film can be sufficiently removed even if the film remains in the pulverized product even if the film is small. Further, in the coating film removing apparatus of the present invention, the entire apparatus is designed in a state close to a closed structure to suppress atmospheric diffusion of the processing liquid and to be circulated and reused. Is also carefully considered.

[0050]

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

[0051]

Embodiment 1 FIG. 1 shows an example of the coating film removing apparatus of the present invention. The apparatus shown in FIG. 1 includes a stirring tank 10 for accommodating a pulverized product of a resin product having a coating film formed on its surface and the above-mentioned removal liquid or cleaning liquid, and stirring them, and a drying tank for drying the pulverized product. 20 and a crushed material conveying means 40 for conveying the crushed material from the stirring tank to the drying tank.

The stirring tank 10 is equipped with a stirring means 15.
A crushed material input port 11 for inputting a crushed product of a resin product having a coating film formed on its surface, an injection port 12 for injecting a removal liquid or a cleaning liquid, and a discharge for discharging the removal liquid or the cleaning liquid. It has a liquid port 13 and a pulverized material outlet 14 for taking out the pulverized material from the tank, and the pulverized material outlet 14 is connected to a pulverized material conveying means 40 for conveying the pulverized material to the drying tank. .

The drying tank 20 has a crushed material input port 21 for charging the crushed material and a crushed material outlet 24 for removing the crushed material from the tank.
Is connected to a pulverized material conveying means 40 for conveying the pulverized material from the stirring tank.

[0054]

[Embodiment 2] FIG. 2 shows another example of the coating film removing apparatus of the present invention. This apparatus includes a dipping tank 30 for immersing a pulverized product of a resin product having a coating film formed on the surface thereof in a removing liquid contained therein, a pulverized product and a removing liquid subjected to an immersion treatment with the removing liquid, or A stirring tank 10 for accommodating the cleaning liquid and stirring them, a drying tank 20 for drying the crushed material, and a hot air generator 7 for generating hot air to be blown to the drying tank.
0, a condenser 80 for liquefying the exhaust gas discharged from the exhaust port of the drying tank, a spring feeder 50 for transferring the crushed material from the immersion tank to the stirring tank, and a crushed material for transferring from the stirring tank to the drying tank. The apparatus is provided with a spring feeder 40 for removing the crushed material and a spring feeder 60 for removing the crushed material from the drying tank.

The dipping tank 30 is provided with a crushed material inlet 31 for charging a crushed resin product having a coating film formed on its surface.
And a drainage port 32 for injecting the removal liquid, a drainage port 33 for discharging the removal liquid, and a crushed material outlet 34 for removing the crushed material from the tank. Is connected to a reserve tank for removing liquid (not shown) via a transfer pipe having a pump, and the drainage port 33 is connected to a reserve tank for removing liquid via a transfer pipe having a pump. The outlet 34 is connected to a spring feeder 50 for conveying the crushed material to the stirring tank.

The agitation tank 10 has a pulverized material inlet 11 for introducing the pulverized material that has been subjected to the immersion treatment, an injection port 12 for injecting a removing liquid or a cleaning liquid, and a discharging liquid for the removing liquid or the cleaning liquid. Has a drainage port 13 and a crushed material outlet 14 for taking out the crushed material from the tank.
Is connected to a spring feeder 50 for transporting the pulverized product from the dipping tank, and the liquid injection port 12 is provided with a reserve tank for the removing liquid and a reserve tank for the cleaning liquid used for neutralization not shown. Also connected to a reserve tank for a cleaning liquid, which is also used for finishing, not shown, via a transfer pipe having a pump and a filter, and the drain port 13 is connected to each of the reserve tanks via a transfer pipe having a pump. The crushed material outlet 14 is connected to a spring feeder 40 for transferring the crushed material to the drying tank.

The stirring means 15 provided in the stirring tank 10 is
It has two stirring shafts 17 each provided with five stirring blades 16 and is arranged so that the stirring blades of each stirring shaft are alternately positioned. Furthermore, the rotation direction of each stirring shaft is independent. It can be set.

The drying tank 20 has a crushed material inlet 21 for charging the crushed material, a blower opening 22 for blowing hot air into the tank, an exhaust port 23 for exhausting the crushed material, and a crushed material for taking out the crushed material from the tank. Of the crushed material, a baffle plate 25 provided inside the tank, and a vibration generator 26 for vibrating the entire tank including the baffle plate attached to the outside of the drying tank,
The crushed material input port 21 is connected to a spring feeder 40 for transporting the crushed material from the stirring tank, the blower opening 22 is connected to the hot air generator 70, the exhaust port 23 is connected to the condenser 80, and the crushed material outlet. 24 is connected to a spring feeder 60 for taking out the crushed material.

The condenser 80 has a drain port for discharging the cleaning liquid obtained by liquefying the exhaust gas of the cleaning liquid transferred from the drying tank, and this drain port is not shown. It is connected to a tank for pH adjustment via a transfer pipe.

Using the above apparatus, the coating film and / or putty of a polypropylene resin automobile bumper on which various coating films were formed or which was filled with a repair putty to form a coating film were removed. The samples used were a mixed pulverized product obtained by mixing a pulverized product of a bumper coated with an acrylic melamine-based paint and a pulverized product of a bumper coated with an alkyd melamine-based paint, and a pulverized product of a bumper coated with a urethane-based paint. It is a mixed pulverized product in which pulverized products of bumpers filled with epoxy putty and coated with urethane paint are mixed.

The removal liquid was 90 vol of methylene chloride.
%, Methanesulfonic acid 5 vol%, methanol 5 vol
%, Methylene chloride having a pH of 12 adjusted by adding ethylenediamine was used as a cleaning liquid for neutralization, and neutral methylene chloride was used as a cleaning liquid for finishing.

Immersion tank 3 containing about 1500 L of removing liquid
Approximately 1200 kg (2000 L) of the above bumper crushed into pellets was charged from the crushed material charging port 31 of No. 0, and immersion treatment was performed for 10 hours. After that, the removal liquid is discharged and transferred to a reserve tank, and then the crushed material is conveyed by the spring feeder 50 to the agitation tank 10 in which about 1450 L of the removal liquid is stored, and the removal state of the coating film is observed with the naked eye. The stirring was repeated until was completely removed. For the mixed pulverized product of the bumper crushed product with the coating film formed of acrylic melamine-based paint and the crushed product of the bumper coated with the alkyd melamine-based paint, the time required for complete removal of the coated film Is about 10 minutes, and about 20 minutes for a mixed pulverized product obtained by mixing a pulverized product of a bumper on which a coating film of urethane-based paint is formed and a pulverized product of a bumper filled with epoxy putty and coated with a urethane-based paint. .

After completion of the stirring treatment with the removing liquid in the stirring tank, the removing liquid is discharged from the stirring tank and transferred to the reserve tank, and then about 1500 L of the cleaning liquid for neutralization is poured into the stirring tank 10 for 10 minutes. Agitate with the neutralization cleaning liquid,
After the stirring is completed, the neutralization cleaning liquid is discharged from the stirring tank and transferred to the reserve tank.
L was poured into the stirring tank 10 and stirred for 10 minutes with the finishing cleaning liquid. After completion of the stirring treatment, the neutralizing cleaning liquid was discharged from the stirring tank and transferred to the reserve tank, and then the pulverized material was transferred to the drying tank 20 by the spring feeder 40.

In the drying tank 20, the spring feeder 40
Thus, the crushed material sequentially charged moves from the upper part of the tank to the lower part of the tank while rolling the baffle plate 25. At this time, the crushed material is completely dried by the hot air blown from time to time. The crushed material accumulated in the lower part of the drying tank is sequentially taken out and is ready for use as a recycled product.

The finishing cleaning liquid adhering to the pulverized material in the drying tank 20 is vaporized by hot air, which is transferred as exhaust gas to the condenser 80 to be cooled and liquefied to adjust the pH, and then re-cooled. Used.

A mixture obtained by mixing the crushed product of the bumper coated with the acrylic melamine-based paint and the crushed product of the bumper coated with the alkyd-melamine-based paint, which is obtained by using the coating film removing method of the present invention as described above. The processed product of the crushed product is the recycled product 1, and the processed product of the mixed crushed product in which the crushed product of the bumper coated with urethane paint and the crushed product of the bumper filled with epoxy putty and painted with the urethane paint are mixed. Was used for the following evaluation.

[0067]

Comparative Example 1 For comparison, a crushed product of the bumper coated with the acrylic melamine-based paint and a crushed product of the bumper coated with the alkyd melamine-based paint used in the above examples were placed in an apparatus equipped with a stirring blade. Add the mixed pulverized product,
To this, methylene chloride and water were added as a removing solution at a volume ratio of 10
The solution mixed at a ratio of 0:10 was added, and the mixture was kept at 40 ° C for 5
Immersion and stirring treatment were performed for 60 minutes under the condition of 00 rpm.
The treated product thus obtained was used as a recycled treated product 3 for evaluation.

<Evaluation of Recycled Products> The three types of reprocessed products obtained in the above Examples and Comparative Examples and unprocessed products thereof (crushed bumper coated with acrylic melamine paint and alkyd melamine paint) The unprocessed product 1 is mixed with the crushed product of the bumper coated in 1., and the crushed product of the bumper coated with urethane-based paint and the crushed product of the bumper coated with epoxy putty and coated with the urethane-based paint are mixed. The mixed pulverized product thus obtained was referred to as an untreated product 2), and various mechanical properties were measured according to JIS standards. For reference, the mechanical properties of the bumper material resin (polypropylene pellets) before being molded were also measured in the same manner. The results are shown in Table 1.

[0069]

[Table 1]

As is clear from these results, the regenerated product obtained by using the coating film removing apparatus of the present invention according to the coating film removing method of the present invention uses a removing liquid having a composition different from that of the present invention. Practical physical properties compared to recycled and untreated products,
In particular, it can be seen that it has the same physical properties as the raw material resin in terms of elongation at break, Izod impact strength, and embrittlement temperature.

[0071]

According to the method of removing a coating film of the present invention, the removing liquid itself has a high effect of removing the coating film, and the coating film can be efficiently removed from the resin product. Further, by using the coating film removing apparatus of the present invention, the coating film can be efficiently removed.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a coating film removing apparatus of the present invention.

FIG. 2 is a side sectional view showing another example of the coating film removing apparatus of the present invention.

[Explanation of symbols]

10. Stirring tank 11. Ground material input port 12. Injection port 13. Drainage port 14. Ground material removal port 15. Stirring means 16. Stirring blade 17. Stirring shaft 20. Drying tank 21. Ground material input port 22. Blower 23. Exhaust port 24. Ground material outlet 25. Baffle 26. Vibration generator 30. Immersion tank 31. Ground material input port 32. Injection port 33. Drainage port 34. Crushed product outlet 40. 50. A pulverized material conveying means for conveying the pulverized material from the stirring tank to the drying tank. 60. A pulverized material conveying means for conveying the pulverized material from the dipping tank to the stirring tank 60. A crushed material conveying means for removing the crushed material from the drying tank 70. Hot air generator 80. condenser

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chuichi Daisaku 1270 Hongo, Sugito-cho, Kita-Katsushika-gun, Saitama Prefecture (270) Inventor Ikatsu Obana Ube-shi, Yamaguchi 1978-10 Kogushi

Claims (11)

[Claims] 1. A method for removing a coating film from a resin product by immersing a resin product having a coating film formed on the surface of a resin substrate in the removal liquid, wherein the removal liquid contains an organic solvent, an acid and an alcohol as main components. A method for removing a coating film from a resin product, comprising: 2. The resin product comprises a resin substrate filled with repair putty, and a coating film formed on the surface thereof.
The method for removing a coating film from a resin product according to claim 1, wherein the repair putty is removed together with the coating film from the resin product. 3. The resin substrate is an olefin-based thermoplastic elastomer, a polyolefin-based resin, polystyrene,
Methacrylic resin, polyamide, polyacetal, polycarbonate, phenol resin, ionomer resin, AB
S resin, ACS resin, AES resin, polyester resin,
The method for removing a coating film of a resin product according to claim 1 or 2, wherein the method is selected from PPO resins or polymer alloys composed of two or more of the resins. 4. The coating film comprises an acrylic resin, a melamine resin, an acrylic melamine resin, an alkyd melamine resin,
4. A urethane resin, a phthalic acid resin, a lacquer enamel, a fluororesin, an epoxy resin, a black resin, a ketone resin, a xylene resin, and a water-based paint emulsion paint as a main component. The method for removing a coating film from a resin product according to item 1. 5. The method for removing a coating film from a resin product according to claim 2, wherein the repair putty is made of a polyester resin and / or an epoxy resin. 6. The organic solvent is selected from methylene chloride, chloroform, dichloroethane, trichloroethylene, perchloroethylene, propyl chloride, butyl chloride, chloropentane, chlorobenzene and dichlorobenzene, and the acid is formic acid, acetic acid, oxalic acid, hydrochloric acid, It is selected from sulfuric acid, nitric acid, methanesulfonic acid, benzenesulfonic acid and toluenesulfonic acid, and the alcohol is methanol, ethanol, 1-
The coating film removing method for a resin product according to any one of claims 1 to 5, which is selected from propanol, isopropyl alcohol, 1-butanol, 2-butanol, and isobutyl alcohol. 7. A stirring tank for accommodating a pulverized product of a resin product having a coating film formed on its surface, and a removing liquid or a cleaning liquid containing an organic solvent, an acid and an alcohol as a main component, and stirring them. A drying tank for drying the pulverized material, and a pulverized material conveying means for conveying the pulverized material from the stirring tank to the drying tank, the agitation tank, a pulverized material charging port for charging the pulverized material, It has a liquid injection port for injecting the removal liquid or the cleaning liquid, a drainage port for discharging the removal liquid or the cleaning liquid, and a crushed product outlet for taking out the crushed product from the tank. By immersing the crushed product in the removed liquid, the removed liquid is discharged, and then the removed liquid is discharged, and the cleaning liquid is injected to wash the crushed product, and at the same time, the tank is stirred when the crushed product is washed with the cleaning liquid By removing the coating film from The pulverized product was transported from the stirred tank to the drying vessel, the coating film removing apparatus resin product characterized in that the cleaning solution remaining was be dried pulverized product. 8. The crushed material charging port for charging a crushed material of a resin product having a coating film formed on a surface thereof, a pouring port for pouring a removing liquid, and a removing liquid according to claim 7. A drainage port for discharging the crushed product, and a crushed product outlet for removing the crushed product from the tank, and an immersion tank for immersing the crushed product in the removal liquid contained therein, and from this immersion tank A second pulverized material conveying means for conveying the pulverized material to the agitation tank is provided, and after the pulverized material is immersed in the removal liquid stored in the dipping tank, the pulverized material is conveyed to the agitation tank, A coating film removing apparatus for resin products, characterized in that a cleaning liquid is injected into the container to clean the crushed material and the inside of the tank is agitated. 9. A plurality of the dipping tanks and the second pulverized material conveying means are provided, and the pulverized materials are sequentially conveyed from each dipping tank to the stirring tank and the drying tank while the pulverized materials are immersed in the removal liquid in the dipping tanks. On the other hand, the coating film removing apparatus for a resin product according to claim 8, wherein the crushed product is newly introduced into the dipping tank from which the crushed product has been taken out, and these operations are continuously performed. 10. The agitation means has two or more agitation shafts provided with a plurality of agitation blades, and the agitation blades of the agitation shafts are arranged so as to alternate with each other. The coating film removing apparatus for a resin product according to any one of claims 7 to 9, wherein the rotating directions of the can be set independently. 11. The drying tank is provided with a crushed material charging port for charging a crushed material, a blower opening for blowing hot air into the tank, an exhaust port for exhausting the crushed material, and a crushing operation for removing the crushed material from the tank. It has a material take-out port, a baffle provided in the tank, and a vibration generator for vibrating at least the baffle, and is further connected to the hot air generator from the exhaust port of the drying tank via a transfer pipe. Equipped with a condenser, the crushed material conveyed to the drying tank is dried by hot air while rolling the baffle from the upper part of the tank to the lower part of the tank, and the cleaning liquid vaporized by the hot air can be liquefied by the condenser and reused. The coating film removing device for a resin product according to any one of claims 7 to 10, wherein