JPH07171832A - Peeling of paint film of painted plastic molded object and regeneration of molded object - Google Patents

Abstract

PURPOSE:To obtain an inexpensive plastic reclaimed product reduced in environmental pollution without lowering the physical properties of the reclaimed product by separating and removing the paint film of a painted plastic molded object. CONSTITUTION:A plastic molded object having painting partially or entirely applied to the surface thereof is cut or not cut to be held under a temp. condition from 70 deg.C to below the m.p. or glass transition point of the plastic to apply stress to the molded object. By this method, the paint film is peeled from the molded object. Then, the molded object from which the paint film is peeled is reclaimed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple and effective method for peeling and recycling a coated plastic molded body, and more particularly to peeling a coated film from a plastic molded body under dry conditions. TECHNICAL FIELD The present invention relates to a plastic recycling treatment technique by which a coating film is not mixed and a recycled product with less deterioration in physical properties is obtained at low cost and low pollution by positively separating and removing the coating film.

[0002]

2. Description of the Related Art Conventionally, plastics have been burned in an incinerator after use or buried in soil together with other refuse. However, when the plastic is burned, the global environment is deteriorated due to global warming due to an increase in carbon dioxide concentration, and even if it is buried in the soil without burning, it is not decomposed by microorganisms and remains as it is. The amount of landfill has been increasing year by year. In recent years, recycling of plastics has been called for in order to reuse the resources and protect the global environment such as global warming due to an increase in carbon dioxide concentration, and this problem has become more and more important. However, in order to recycle and reuse used plastic, various difficult problems must be solved. One of such problems is that the plastic used as the final product may use only a single component in its material, but the final product is often obtained by combining different materials. . If the final product thus composited is reused after use without separating the different materials, the recycled products will lose the original excellent physical properties of the respective plastic materials themselves. As a result, the required physical properties such as strength could not be obtained, and only those with significantly impaired design properties such as appearance could be obtained. For example, the final product obtained by painting plastic is crushed as it is after use, re-pelletized by an extruder, and re-molded by a molding machine, and the obtained reclaimed product has a coating formed on the surface of the plastic. The film is not finely dispersed and remains as it is in the recycled product. Therefore, since the coating film which is not finely dispersed prevents the kneading and integration in the recycled resin and remarkably deteriorates the physical properties of the recycled product, it is impossible to obtain a practical product. Therefore, as the technique for peeling and removing the coating film from the final product coated with plastic, the following various techniques (1) to (4) can be considered, but all of them have problems in practical use.

As a method of removing the coating film from the coated plastic product, first, a method of melting the plastic in the extruder and separating the material of the coating film portion which does not melt by filtering with a screen such as a wire mesh can be considered. In such a method, the amount of extrusion is reduced due to a significant increase in extrusion pressure due to the clogging of the screen, and the production amount is significantly reduced. Further, the effect of removing the material in the coating film portion is poor, and a good recycled product cannot be obtained. Therefore, in order to cover the decrease in production efficiency due to the blockage of the screen, it is conceivable to equip an automated filter exchanger or take a large filtration area, but any method should be satisfied. It is not a technology that can In order to remove a coating film from a coated plastic product, JP-A-5-93157 discloses a method in which a large amount of a strong alkali is used to hydrolyze the coating film to prevent the coating film from being mixed into the product. However, it requires a separate facility for wastewater treatment, which increases the treatment cost and is not a practical technique. In order to remove a coating film from a painted plastic product, a method of swelling the coating film with an organic solvent and then peeling it off is also considered to be an effective method. Since it costs a lot of money, the cost becomes high, and there is a concern about secondary pollution due to the use of the organic solvent. As a method for removing a coating film from a coated plastic product, JP-A-2-273207 proposes a method in which a coating film on a plastic surface is blasted using a soft abrasive, peeled, and regenerated. ing. But,
When the coating surface has a complicated shape, the method not only lowers the treatment efficiency but also makes it difficult to completely remove the coating film. In addition, this technique is not suitable for continuously processing products having different shapes. As a method for removing a coating film from a coated plastic product, Japanese Patent Application No. 3-192431 discloses a coated plastic product in which water or an organic solvent such as alcohol is used, and the melting point of the resin is below or above the melting point of the resin. It is a method of heating the coating material to hydrolyze the coating material, and then melting and kneading it to disperse the decomposed coating film in the resin. The treatment cost or the drying process is required, the treatment cost becomes high, and the decomposed coating film is finally dispersed in the resin.
The physical properties of the recycled product are likely to deteriorate.

[0004]

As described above, it is an unsolved problem how low cost and high quality plastic molding can be recycled from the final product of the painted plastic molding. It was

[0005]

[Means for Solving the Problems]

[Summary of the Invention] The present inventors have conducted extensive studies in view of the above problems, and as a result, the temperature of a plastic molded body on which a coating film has been formed is 70 ° C or higher and lower than the melting point or glass transition point of the plastic. By heating within the temperature range, the adhesion between the primer layer or the coating film and the molding material base material is significantly reduced, and the coating film can be peeled off by applying stress to the primer layer. The present invention has been completed based on the finding that can be reproduced. That is, the method for peeling off the coating film of the coated plastic molded article of the present invention is carried out at 70 ° C. with or without cutting the plastic molded article whose surface is partially or entirely coated.
Under the temperature conditions below the melting point or glass transition point of the plastic, stress is applied to the plastic to peel off the coating film. A method for reclaiming a coated plastic molded article according to the other aspect of the present invention is a plastic molded article whose surface is partially or wholly coated, cut or uncut, at 70 ° C. or higher or the melting point of the plastic or Stress is applied to this under a temperature condition below the glass transition point to peel off the coating film, and then the peeled plastic is blended with or without other optional components and melt-molded again. To do.

[Detailed Description of the Invention] [I] Method of Treating Painted Plastic Molded Body (1) Raw Material (a) Painted Plastic Molded Body The plastic molded product whose surface is partially or wholly coated is a plastic product whose part is coated, regardless of the outer surface or the inner surface of the molded product base. Means a product that has been used for its original purpose, or a product that has been manufactured for the purpose of use but has become a defective product during manufacturing or for other reasons. The above plastic products are injection molding, extrusion molding, blow molding, transfer molding, various molding methods such as press molding of thermoplastic resin, automobile exterior parts such as automobile bumpers, wheel caps, side moldings, instrument panels. , Interior parts such as levers and linings, vacuum cleaners,
It refers to a molded product molded into various shapes such as a washing machine, a refrigerator, a lighting fixture, and an electric appliance such as an audio device. In the present invention, at least a part of the molded product base material may be an outer surface or an inner surface. It is intended for all products that consist of painted items.

(B) Molded-material base material Specific examples of the molded-material base material made of the above-mentioned thermoplastic resin include ethylene-based resins such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. , Propylene homopolymer, olefin resin represented by propylene resin such as propylene / ethylene block or random copolymer, thermoplastic polyester resin such as polyethylene terephthalate or polybutylene terephthalate, polyamide, polycarbonate, polyphenylene ether, poly An engineering resin such as oxymethylene, a styrene-based resin such as an acrylonitrile-styrene copolymer or an acrylonitrile-styrene-butadiene copolymer, or a composite material (including an alloy) of each of these resins and the like is used. But Kill.
Among the molding base materials made of these thermoplastic resins, olefin resins represented by ethylene resins, propylene resins and the like or composite materials using the same are preferable, and propylene resins are particularly preferable. Among these molded body substrates, components other than the thermoplastic resin, such as talc,
Inorganic fillers such as glass fiber, titanium oxide, carbon, natural rubber, ethylene / propylene copolymer rubber, styrene / butadiene rubber, styrene / isoprene rubber, acrylonitrile / butadiene rubber, isoprene rubber, urethane rubber, styrene / diene block copolymer It may contain a rubber component such as a combined hydrogenated product, and a compounding material such as an organic pigment such as quinacridone or ferrocyan blue.

(C) Coating Primer The coated plastic molding used in the method for peeling off the coating film of the coated plastic molding of the present invention and the method for reclaiming the same directly coats the base material on the plastic molding without using a primer. Although it may be painted, a material may be used which is applied after applying a primer in advance to form a primer layer before applying the plastic molded body substrate. As the primer, modified propylene resin such as chlorinated polypropylene resin (chlorinated PP), maleated polypropylene (maleated PP) and styrene / ethylene / butylene / styrene polymer (SEBS)
Polymers) or styrene / ethylene / propylene / styrene polymers (SEPS polymers). Among these, it is preferable to use a chlorinated polypropylene resin. In these primers, the primer layer is generally formed with a thickness of 3 to 30 μm, preferably 5 to 15 μm.

Coating materials Generally used widely as organic solvent-based coating materials and water-soluble resins as coating materials used to form a coated plastic molded article by coating a part or all of the surface of the above-mentioned molded article substrate. Examples thereof include paints, water-dispersible resin paints and water-based emulsion paints. Specific examples of these paints include paints in which the resin component of the paint is acrylic, epoxy, polyester, alkyd, etc., and the crosslinking component is urethane or melamine.
Among these paints, it is preferable to use a paint in which the resin component is an acrylic type or a polyester type and the crosslinking component is a melamine type urethane type (isocyanate crosslinking type). These paints have only to have a commonly used thickness, for example, a thickness of 20 to 200 μm, preferably 30 to 100 μm, and a range of 10% by weight or less, preferably 7% by weight or less with respect to the molded body substrate. It was used. According to the present invention, the coating film can be easily peeled off even when the coating material is directly applied to the plastic molding base material without using the primer.

(2) Optimization of shape In order to peel off the coating film of the coated plastic molded body, the coating film can be peeled off without cutting the coated plastic molded body. It is necessary to apply a stress equal to or higher than the adhesive strength to the coating film, and when stress is applied to the coating film with a stress generator such as a roll or a brush described later, the stress is transmitted efficiently and peeling is more sufficiently performed. In order to carry out, the shape of the coated plastic molding is cut in advance and the coating surface area is generally 0.25 cm ² or more,
Preferably 1 cm ² or more, particularly preferably 100-30
It is better to have a size of 0 cm ² . In the case of a coated plastic molded product having a size smaller than the above range, even if stress is applied to the coated plastic molded product, it is difficult to apply a stress equal to or higher than the adhesive strength to the coating film, and peeling cannot be sufficiently performed, The molded body and the coating film cannot be sufficiently fixed, and it is difficult to apply a stress equal to or higher than the adhesive strength to the coating film, so that peeling cannot be sufficiently performed. Further, in the case of a large product, only a smooth and nearly flat portion may be cut, and this may be selectively used for the method for peeling off the coating film of the coated plastic molding of the present invention. A crusher, a shredder, a shear cutter, a saw, a water jet, or the like is used as an apparatus for forming the above-mentioned coated plastic molded body into an optimum shape when applying stress.

(3) Heat Treatment In the method for peeling a coating film of a coated plastic molding of the present invention, it is necessary to perform a heat treatment before or simultaneously with peeling by applying stress to the coating film. The heat treatment is performed using an electric hot air circulation dryer, a burner hot air circulation dryer, a high-frequency heater, or the like, and the coating film surface temperature of the coated plastic molded body is 70 ° C. or higher to less than the melting point or glass transition point of the plastic molded body. At 70 ° C. or higher, preferably 5 ° C. or lower than the melting point or glass transition point of the plastic molded body, particularly preferably 50 to 5 ° C. lower than the melting point or glass transition point of the plastic molded body. Be done. The heat treatment is maintained for 15 to 180 minutes, preferably 30 to 150 minutes, particularly preferably 60 to 120 minutes in the above temperature range in the case of heating in an atmosphere using a hot air circulation dryer or the like. The method of heat treatment at this time may be batch type heating or continuous heating such as tunnel type heating.
Specifically, in the case of propylene-based resin, it is generally 70 to 16
5 ° C., preferably 70-160 ° C., particularly preferably 11
It is within a temperature range of 5 to 160 ° C. The reason why the coating film can be easily peeled off by heating the coated plastic molded body at a specific temperature and then applying a stress to the coating film has not yet been sufficiently clarified. However, the strength of the primer or coating film applied between the plastic molded body base material and the coating layer is lowered by the heat treatment, so that the adhesion between the plastic molded body base material and the coating material is significantly reduced. Therefore, it is presumed that the coating film may be easily peeled off. Therefore, in order to reduce the strength of the primer or the coating film, it is necessary to maintain the temperature of at least 70 ° C. or higher for at least 15 minutes in the case of heating in an atmosphere such as a hot-air circulating dryer. In the case of induction heating, the strength can be reduced in a shorter time.

(4) Stress generator In the method for peeling a coating film of a coated plastic molding of the present invention, in order to peel the coating film, bending, rubbing, striking, peeling, etc. of the coating film with a strength higher than the adhesive strength of the coating film are carried out. It is necessary to apply the above stress, and as an apparatus for applying the stress to the coating film of such a coated plastic molded article, there are the following ones.

The roll type roll device is one in which two rolls having the same diameter or different diameters are arranged in parallel to each other and a gap is formed between the two rolls. The width of the gap is such that when the coated plastic molded body is passed through, the plastic molded body is compressed, and the coated surface side of the plastic molded body becomes a coated film portion due to the speed difference between the outer peripheral portions of both rolls. It is formed so that shear stress (stripping stress due to displacement) can be applied. In particular, when the diameters of the rolls are the same, the rotational speed can be changed to give shear stress to the coating film, and when the diameters of the rolls are different, the rotational speeds of the rolls can be the same and they can be rotated at different peripheral speeds. The material of the roll is preferably made of metal because it effectively produces shear in the coating film, but it is not necessarily required to be metal. As a method of effectively generating shear in the coating film, it is preferable to make the surface of the roll rough with a satin finish, embossing or engraving and to increase the friction coefficient, but the coating can be peeled off even on a mirror surface. .
Shear stress tends to be applied to the coating film by arranging the side where the coating film is formed on the side where the roll rotation speed is high and arranging the molded body substrate side on the side where the rotation speed is low. . The larger the roll rotation ratio or the peripheral speed ratio, the larger the shear stress applied to the coating film, and the more easily the coating film peels off. The roll is generally rotated in the same direction as the direction of travel of the coated plastic molding, but one of the rolls may be rotated in the opposite direction.
The narrower the roll gap, the higher the compression ratio of the coated plastic molding and the greater shear stress, and the more easily the coating film peels off. However, if the compression rate is too high, the penetration into the roll becomes poor and the pushing force must be increased, or the resin part of the plastic molded product is delaminated, and the peeled coating film enters into it It gets mixed in with. When the roll is a mirror surface and the roll rotation ratio is 1: 4, the compression ratio on the roll is generally 40.
~ 80%, preferably 50-70%. The apparatus is provided with a roll that can adjust the gap between the metal rolls and the number of rotations of the rolls individually, and can heat the roll surface. The heating of the roll may employ any heating method such as electricity, steam or oil. Also, after peeling with a roll,
Further, if brushing described later is carried out, peeling becomes easier, and the peeled coating film becomes easier to separate.

The shear stress (peeling stress due to displacement) is the difference in compression rate due to the difference between roll intervals and the thickness of the coated plastic molding, the difference in roll peripheral speed, and the difference in roughness of the roll surface. , The heating temperature of the roll,
Changes due to differences in roll equipment such as roll force, type of coating film, adhesive strength between coating film and plastic molded product, physical properties such as elasticity of coated plastic molded product, and material such as size Therefore, it is not possible to determine the value unconditionally, but when peeling of the coating film cannot be peeled at once, it is sufficient to pass the roll again to apply shear stress. In addition, a roll device in which a plurality of pairs of the above-mentioned rolls that are parallel to each other are combined, or three rolls are used.
It is also possible to use a roll device in which one or more pieces are alternately combined in parallel.

Brushing method A brush having a rotatable brush made of metal or plastic and having a transfer device capable of brushing along the surface of the plastic molded body, or a device or tool capable of being brushed by hand. is there. A metal brush is particularly effective, and it is also possible to blow a compressed gas to accelerate the separation and blow off the separated coating material to separate it from the plastic.

Rotation, contact type Rotating the coated plastic molded body with a rotary blade, compressed gas, etc., and contact the molded body with each other or with an arbitrarily selected abrasive to the molded body, A contact device capable of generating stress. It is preferable that the inside of the contact device has a structure capable of heating so that the peeling can be performed while heating. The heating is preferably carried out under the same temperature conditions as the above heat treatment. In order to promote the peeling, it is preferable to peel the metal-based or high-hardness plastic by simultaneously filling the inside of the contact device with an abrasive and stirring the mixture.

[II] Regeneration of Plastic Molded Product (1) Small Particle Processing The above-mentioned coating film is peeled off, and the molded base material from which this has been removed is first made into small pieces suitable for the subsequent molding step.

(2) Composition The molded body substrate from which the coating film has been peeled off is melted again in an extruder,
It is pelletized and recycled, but at this time, virgin plastic or other additional components can be mixed and used as an optional component. The unused plastic may be the same plastic as the recycled plastic or a different plastic. Moreover, the following can be mentioned as an example of the other additional component mix | blended with the said recycling process product. That is, hindered phenolic,
Sulfur-based and phosphorus-based antioxidants, hindered amine-based, triazole-based, benzophenone-based, benzoate-based, nickel-based, salicylic acid-based light stabilizers, antistatic agents, lubricants, peroxides and other molecular weight regulators, metals Examples include inactivating agents, organic and inorganic nucleating agents, neutralizing agents, antacids, antibacterial agents, fluorescent whitening agents, fillers, flame retardant aids and the like.

(3) Molding The molded body substrate from which the coating film has been peeled off is melted again in an extruder and, if necessary, pelletized for recycling. The extruder used for pelletizing is not special, and a generally used single-screw or twin-screw extruder can be used. In order to remove dust, metal, etc. which could not be removed in the coating film peeling step, etc.
It can also be removed by using a wire mesh of up to 200 μm or a filter. However, re-pelletization by an extruder is not essential, and the final product can be directly molded from a recycled product. As the molding method, various molding methods such as injection molding, extrusion molding, blow molding, transfer molding, and press molding can be adopted. The molding conditions are appropriately set depending on the properties of the plastic, the shape of the molded product, and the like.

(4) Coating The regenerated molded article of the molded body substrate is a regenerated plastic molded body without coating, or the organic solvent-based paint, water-soluble resin paint, water-dispersible resin paint and A paint such as an aqueous emulsion paint may be applied to a part or all of the surface of the molded product base material after or without applying a primer to obtain a coated plastic molded product. These paints are generally used in an amount of 10% by weight or less, preferably 7% by weight or less, based on the molded body substrate. In the case of applying the above-mentioned coating, in the same way as the method performed in the method for peeling off the coating film of the plastic molded body of the present invention, a primer should be applied in advance before coating the plastic molded body base material. Is preferred.

(5) Product The plastic molded product regenerated as described above can be applied with or without coating, and can be applied again as various industrial products. Specifically, automotive bumpers, wheel caps, automobile exterior parts such as side moldings, instrument panels, interior parts such as levers and linings, vacuum cleaners, washing machines, refrigerators, lighting equipment, audio equipment, and other electrical products. Etc. can be mentioned.

[0022]

EXAMPLES In order to describe the method for peeling off the coating film of the coated plastic molded article of the present invention in more detail, the examples and comparative examples will be specifically described below. However,
The present invention is not limited to these examples.

Examples 1 to 10 and Comparative Examples 1 to 4 (1) Manufacture of Base Resin for Molded Body Melt flow rate (MF) with ethylene content of 5% by weight
R) is 30 g / 10 minutes and the propylene / ethylene block copolymer is 68% by weight, and the melt flow rate is 20 g /
10 minutes, 10% by weight of an ethylene-based polymer having a density of 0.96 g / cm ³ , and an ethylene content of 80% by weight at 100 ° C.
20% by weight of an ethylene / propylene copolymer rubber having a Mooney viscosity (ML _{1 + 4} ) of 70, and an average particle size of 2
A molded body base resin made of a resin composition mixed with 2% by weight of talc of μm was produced. The melting point of this molded base resin was 165 ° C.

(2) Manufacture of coated plastic products (a) Molding of injection-molded products Using the N-100BII type injection molding machine manufactured by Nippon Steel Co., Ltd., the molding base resin described above is molded at a molding temperature of 220 ° C. and an injection pressure of 600.
Injection-molded product (120mm × 1) under the condition of kg / cm ^2.
20 mm × 3.5 mm) was molded. (b) Application of primer Next, the injection-molded article was steam washed with 1,1,1-trichloroethane to obtain a chlorinated polypropylene resin (chlorinated P
A primer mainly composed of P) was applied in a thickness of 5 μm. (c) Manufacture of painted plastic product Manufacture of painted plastic product A, and then apply a one-component white paint of 40 μm thick with a resin component of the paint of acrylic type and a melamine type of cross-linking component in an oven. A coated plastic product A was produced by baking at 100 ° C. for 60 minutes. Manufacture of painted plastic products B Meanwhile, injection-molded products (1
20 mm x 120 mm x 3.5 mm), a two-component white paint having a urethane resin as a paint component and urethane as a crosslinking component is applied to a thickness of 40 µm, and then baked in an oven at a temperature of 90 ° C for 30 minutes. The coated plastic product B was manufactured. Manufacture of coated plastic product C Further, the injection molded product (120 mm × 120 mm × 3.
5 mm) by the method described in JP-A-59-98140 (apparatus: microwave plasma processing apparatus (TMZ-9602B manufactured by Toshiba Corporation), conditions: oxygen gas flow rate 400 cc / min, pressure 0.5 torr, output) 400
W, treatment time 10 seconds), and the resin component of the paint is acrylic and the one-component white paint containing urethane bond (the cross-linking component is melamine) is applied to this with a thickness of 40 μm.
A coated plastic product C was produced by baking in an oven at a temperature of 120 ° C. for 30 minutes.

(3) Peeling of coating film The coated plastic products A and B were subjected to heat treatment as described below, and the coating film was peeled by a roll method. In addition, about Example 7-Example 10, the film peeling by the brushing system was implemented after roll peeling. (a) Heat treatment The coated plastic products A and B were heated at a temperature of 30 to 170 ° C. for 2 hours using an electric hot air dryer. (b) Stripping of coating film by roll method Next, stripping of coating film by roll method was performed. The roll used for peeling the coating film by the roll method was two rolls, the diameter of the roll was 152.4 mm ^φ , and the length was 38.
0 mm, the rotation speed of the roll is 16 rpm on one side,
The other was rotated at 20 rpm. The roll was heated with an electric heater in the range of 30 to 170 ° C. The gap between the rolls was variously changed within the range of 1.0 to 3.0 mm. In addition, in Examples 4, 5, 9 and 10, one roll rotation speed was 6 rpm and the other rotation speed was 24 rpm. (c) Peeling of coating film by brushing method Peeling of coating film by brushing method, after peeling the coating film by the roll method, further peeling the coating film by brushing with a steel brush Promoted. The results are shown in Tables 1 and 2.

(4) Regeneration The plastic product from which the coating film of Example 3 peeled off obtained by the above method was crushed by a crusher and placed in an extruder, and after heating, melting and kneading again. When pelletized and injection-molded, a molded product of a recycled product was obtained, the product was painted again, and the mechanical strength (impact strength, rigidity, elongation, etc.) of the coated product was measured. It was possible to obtain a recycled product of a painted plastic product with no physical properties. The appearance was almost the same as that of the virgin resin.

Examples 11 to 15 and Comparative Example 5 Regarding the shape of the coated plastic products, the plastic sheet coated with a cutter was cut into the size shown in Table 3, and the same apparatus as in Example 2 was used. The coating film was peeled off in the same manner as in Example 2 except that the coating was carried out under the conditions shown in 3. In addition, Example 15 was performed in the same manner as in Example 4 with respect to the rotation number of rolls. The results obtained are shown in Table 3.

Examples 16 to 24 and Comparative Examples 6 to 10 (1) Peeling of coating film The coated plastic products A, B and C obtained in the above Examples 1 to 4 were used, and heating was carried out as in Example 1. Using the same apparatus, as shown in Table 4, after heating at a temperature of 30 to 165 ° C. for 1 hour, respectively, after taking out to room temperature and rubbing the coating film surface with a wire brush to peel the coating film, 3 kg / c
The coating film was blown off with compressed air of m ² . (2) Regeneration As a result of molding a molded body using the regenerated resin from which the coating film thus obtained was removed, a product which was not deteriorated in appearance and physical properties and was comparable to the molded body made of virgin resin was obtained.

Example 25 and Comparative Example 11 The above-mentioned coated plastic product A was used and its size was 5
10 mm, and using the same heating device as in Example 1, 160 ° C. (Example) or 3 as shown in Table 5.
It heat-processed at the temperature of 0 degreeC (comparative example) for 2 hours. Next, a Henschel type mixer having an internal capacity of 20 liters was heated with steam to a temperature of 100 ° C., the heat-treated sample was put therein, and the mixture was rotated at a rotation speed of 1,000 rpm for 5 minutes. The coatings were peeled off by contacting the molded body samples. The results are shown in Table 5.

Examples 26 to 36 and Comparative Examples 12 to 15 Using the above-mentioned coated plastic product A, the roll gap was 1.0 to 3.5 mm and the number of rotations of the roll was the base material side as conditions for peeling the coating film on the roll. 6 to 24 rpm, coating side 6 to 60 r
The pm and roll surface finishes were performed on mirror and grained rolls. The obtained results are shown in Table 6.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

[0036]

[Table 6]

Evaluation Criteria Evaluation criteria for peeling of the coating film in Tables 1 to 5 are as follows. A: The coating film was completely peeled off. ◯: The coating film was peeled off by about 80 to 95%. X: The coating film could not be peeled off.

[0038]

EFFECTS OF THE INVENTION The method for peeling a coating film of a coated plastic molded product of the present invention is to apply a stress to a coated plastic molded product by heating the coating film of the coated plastic molded product in a dry manner to positively apply the coating film. Since it can be separated and removed, since the coating film is not mixed in the obtained recycled product, the physical properties of the recycled product are not deteriorated, and the inexpensive recycled plastic recycled product can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Tsuruda 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Yokkaichi Research Institute

Claims (12)

[Claims] 1. A plastic molded product having a part or all of its surface coated with or without cutting under a temperature condition of 70 ° C. or higher and lower than the melting point or glass transition point of the plastic. A method for peeling a coating film of a coated plastic molded article, which comprises applying a stress to peel the coating film. 2. The method according to claim 1, wherein the stress is applied while heating while applying the stress. 3. The method according to claim 1, wherein the heat treatment is performed under a dry process. 4. The method according to claim 1, wherein the plastic is an olefin resin. 5. The method according to claim 1, wherein the surface area of the coating film of the plastic molding when applying a stress to the coating film is 0.25 cm ² or more. 6. The method according to claim 1, wherein the stress is applied by contact with a roll, a brush, or an abrasive or the molded body. 7. A plastic molding having a part or all of its surface coated with or without cutting under a temperature condition of 70 ° C. or higher and lower than the melting point or glass transition point of the plastic. Apply stress to release the coating, then
A method for reclaiming a coated plastic molding, characterized in that the peeled plastic is blended with or without other optional components and melt-molded again. 8. The method according to claim 7, wherein the stress is applied while heating. 9. The method according to claim 7, wherein the heat treatment is performed under a dry process. 10. The method according to claim 7, wherein the plastic is an olefin resin. 11. The coating film surface area of the plastic molded body when stress is applied to the coating film is 0.25 cm ² or more.
The method described in. 12. The method according to claim 7, wherein the stress is applied by contact with a roll, a brush, or an abrasive or the molded body.