JP2013035205A - Method for manufacturing recycled polypropylene resin formed body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can recycle polypropylene resin vehicle exterior members without deteriorating a physical property of a polypropylene resin foamed body, and can also recycle the polypropylene resin vehicle exterior members without sorting them even if the polypropylene resin vehicle exterior members which are coated with solvent-based paint and water-based paint are mixed.SOLUTION: The method for manufacturing a recycled polypropylene resin foamed body includes: a step of bring a crushed subject for the vehicle exterior members including the polypropylene resin formed body and a resin coating film into contact with a coating removal agent having at least one of d-limonene and benzylalcohol, and a butylcellosolve and formic acid to remove the crushed subject from the resin coating film; a step of collecting the crushed subject after the coating film is removed to manufacture a polypropylene resin pellet; and a step of using the polypropylene resin pellet to manufacture the polypropylene resin foamed body.

Description

  The present invention relates to a method for producing a recycled polypropylene resin molded body, and more particularly, a polypropylene resin is regenerated from a polypropylene resin automobile exterior member provided with a resin coating film, and a polypropylene resin molded body is produced using the polypropylene resin. It relates to a method of manufacturing.

  Polypropylene resins are highly versatile, inexpensive, and excellent in various physical properties, and are used for automotive exterior members such as automotive bumpers. Various methods have been studied for the recycling of such polypropylene resin automotive exterior members, but the surface of the automotive exterior member is usually painted, and this resin coating is used. Since the film deteriorates the physical properties of the recycled polypropylene resin molded article, it has been a big problem in recycling the exterior member made of polypropylene resin for automobiles.

  Then, in order to suppress the fall of the physical property of the recycled polypropylene resin molded product, the method of peeling a resin coating film using a coating film peeling agent was examined. However, conventional coating film release agents contain halogen solvents, amine solvents, strong acids or strong alkalis. Such coating film release agents are not only resin coating films but also polypropylene resin molded products. Therefore, it was difficult to sufficiently suppress the deterioration of the physical properties of the recycled polypropylene resin molded product.

  For this reason, as a method for peeling a resin coating film while suppressing the deterioration of the polypropylene resin, Japanese Patent Application Laid-Open No. 2003-48210 (Patent Document 1) discloses that a resin coating material is applied to a coating film peeling agent substantially made of cyclohexanone. Method of reusing a polypropylene resin molded product in which a polypropylene resin molded product having a film is immersed and the resin coating film is peeled off, and then the polypropylene resin is recovered and pelletized, and injection molding is performed using the polypropylene resin pellet. Has been proposed.

JP 2003-48210 A

  However, the coating film release agent made of cyclohexanone has high releasability of the resin coating film formed with the solvent-based paint, but it is difficult to peel off the resin coating film formed with the aqueous paint. . For this reason, when a polypropylene resin molded product is regenerated using a coating film release agent made of cyclohexanone, it is necessary to separate the polypropylene resin molded product having the resin coating in advance according to the type of the resin coating. was there.

  The present invention has been made in view of the above-described problems of the prior art, and can regenerate a polypropylene resin automotive exterior member without deteriorating the physical properties of the resulting polypropylene resin molded article. Even when a polypropylene resin automotive exterior member painted with a solvent-based paint and a polypropylene resin automotive exterior member painted with a water-based paint are mixed, they can be regenerated without separation. It aims to provide a simple method.

  As a result of intensive studies to achieve the above object, the present inventors have found that a solvent system is obtained by using a coating remover containing at least one of d-limonene and benzyl alcohol, butyl cellosolve and formic acid. The resin coating film can be easily removed and regenerated both in polypropylene resin automotive exterior members painted with paint and polypropylene resin automotive exterior members painted in water-based paint. The present inventors have found that the properties of the polypropylene resin molded product are sufficiently high and have completed the present invention.

  That is, the method for producing a recycled polypropylene-based resin molded body of the present invention includes a crushed material of an automotive exterior member provided with a polypropylene-based resin molded body and a resin coating film, at least one of d-limonene and benzyl alcohol, A step of contacting butyl cellosolve and a coating film release agent containing formic acid to remove the resin coating film from the crushed material, and a step of recovering the crushed material after removing the coating film to produce polypropylene resin pellets; And a step of producing a polypropylene resin molded body using the polypropylene resin pellets. As the coating film peeling agent, those further containing a nonionic surfactant are preferable.

  In the method for producing a recycled polypropylene resin molded body of the present invention, the resin coating film is physically removed from the crushed material when or after the crushed material and the coating film release agent are brought into contact with each other. Is preferred. Moreover, when the said exterior member for motor vehicles is further provided with a primer layer between the said resin coating film and the said polypropylene resin molded object, this primer layer is removed from the said crushed material with the said resin coating film. Is possible.

  The polypropylene resin molded body regenerated in this way can be used as an automotive exterior member.

  According to the present invention, a polypropylene resin automobile exterior member can be regenerated without deteriorating the physical properties of the resulting polypropylene resin molded article, and the polypropylene resin automobile is coated with a solvent-based paint. Even when an exterior member and a polypropylene resin automotive exterior member coated with a water-based paint are mixed, it is possible to regenerate them without sorting them.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  The method for producing a recycled polypropylene-based resin molded body of the present invention includes a crushed material for an automotive exterior member comprising a polypropylene-based resin molded body and a resin coating, at least one of d-limonene and benzyl alcohol, butyl cellosolve, and A step of removing the resin coating film from the crushed material (a coating film removing step) by contacting a coating film release agent containing formic acid, and recovering the crushed material after removing the coating film to obtain a polypropylene resin pellet. It is a method including a step of producing (granulation step) and a step of producing a polypropylene resin molded body using the polypropylene resin pellets (molding step).

<Coating film removal process>
First, an automotive exterior member that can be regenerated by the present invention and a crushed product thereof will be described. The exterior member for automobiles used in the present invention includes a polypropylene resin molded body and a resin coating film formed on at least a part of the surface thereof. Moreover, in such an automotive exterior member, a primer layer may be further formed between the resin coating film and the polypropylene resin molded body. Such automobile exterior members include automobile bumpers and the like. Further, such an automobile exterior member may be defective in the automobile manufacturing process, or may be removed from a discarded automobile.

  The polypropylene resin molded body (hereinafter abbreviated as “PP resin molded body”) is not particularly limited as long as it is used for an automotive exterior member such as an automobile bumper. Extruded molded products, injection molded products, foamed molded products, and the like. Moreover, rubber components such as ethylene-propylene copolymer rubber and ethylene-propylene-diene copolymer rubber may be blended with such a PP resin molded body. Furthermore, various additives such as fillers, pigments, antioxidants, ultraviolet absorbers, and heat stabilizers may be blended.

  The resin coating film is not particularly limited as long as it is formed by a paint used for coating automotive exterior members such as automotive bumpers. For example, acrylic urethane resin coating film, urethane resin coating film, acrylic resin Examples thereof include a coating film made of an organic resin such as a coating film, a polyester resin coating film, a melamine resin coating film, and a phenol resin coating film. These resin coating films may be aqueous resin coating films formed from aqueous resins or solvent-based resin coating films formed from solvent-based resins. In the present invention, a resin PP film can be easily removed regardless of whether it is an automotive exterior member having either a water-based or solvent-based resin coating, and a recycled PP resin molded article having predetermined physical properties is obtained. be able to. The resin coating film may be a single layer or a multilayer of two or more layers. In particular, in the present invention, it is possible to remove a multilayer resin coating film in which an aqueous resin coating film and a solvent-based resin coating film are mixed. Although there is no restriction | limiting in particular as a film thickness of such a resin coating film, Usually, it is 5-50 micrometers. When the film thickness of the resin coating exceeds the upper limit, the resin coating may not be completely removed.

  Moreover, as said primer layer, what was formed with the undercoat of the exterior member for motor vehicles, such as a bumper for motor vehicles, is mentioned. Such undercoat paints include water-based and solvent-based chlorinated polyolefin resin paints. In the present invention, regardless of whether the primer layer is aqueous or solvent-based, both the resin coating film can be easily removed, and a recycled PP resin molded article having predetermined physical properties can be obtained. Can do. Although there is no restriction | limiting in particular as thickness of such a primer layer, Usually, it is 5-20 micrometers. If the thickness of the primer layer exceeds the upper limit, the primer layer may not be completely removed.

  In the present invention, such an automotive exterior member is crushed with a crusher or the like and then brought into contact with a coating film release agent. Although there is no restriction | limiting in particular as a magnitude | size of a crushed material, Usually, it grind | pulverizes into 10 mm square-100 mm square. If the size of the crushed material is less than the lower limit, the crushed material after peeling the coating film and the coating film release agent may not be easily separated. On the other hand, if the size exceeds the upper limit, The contact area of the resin may decrease, and the resin coating film may not be sufficiently removed.

  Next, the coating film release agent used when removing the resin coating film will be described. The coating film release agent used in the present invention contains at least one of d-limonene and benzyl alcohol, butyl cellosolve, and formic acid. By using such a coating film release agent, it is possible to easily remove any aqueous or solvent-based resin coating film and primer layer from the crushed material without deteriorating the PP resin. As a result, even when a water-based resin coating film and a solvent-based resin coating film are mixed, they can be removed from the crushed material without being separated.

  As content of d-limonene and benzyl alcohol in the said coating film peeling agent, 5-50 mass% is preferable and 20-45 mass% is more preferable. If the content of d-limonene and benzyl alcohol is less than the lower limit, the peelability of the resin coating film tends not to be sufficiently obtained. On the other hand, if the content exceeds the upper limit, d-limonene is excessive in the PP resin molding. Or benzyl alcohol adheres to the surface of the molded PP resin, and in any case, the coating film release agent tends to remain on the PP resin.

  Moreover, as content of butyl cellosolve, 20-85 mass% is preferable, and 30-60 mass% is more preferable. When the content of butyl cellosolve is less than the above lower limit, the action of swelling the resin coating film is remarkably reduced, and the peelability of the resin coating film tends to be insufficient. The action of peeling from the PP resin molded product tends to decrease, and the peelability of the resin coating film tends to be insufficient.

  Furthermore, as content of formic acid, 5-25 mass% is preferable and 10-20 mass% is more preferable. When the content of formic acid is less than the lower limit, the cracking action on the resin coating film is reduced, and therefore, the peelability of the resin coating film tends to be insufficient. On the other hand, when the upper limit is exceeded, the coating film is peeled off. The stability of the coating film release agent tends to decrease, for example, the agent is separated over time.

  Moreover, it is preferable that the coating film peeling agent used for this invention contains the nonionic surfactant. Thereby, it exists in the tendency for the peelability of a resin coating film to improve. Examples of such nonionic surfactants include alkylene oxide adducts of higher alcohols, and among them, C10-22 saturated or unsaturated aliphatics from the viewpoint of improving the peelability of the resin coating film. Alkylene oxide (2 to 4 carbon atoms) adducts are preferable, and ethylene oxide adducts of the aliphatic alcohols are more preferable. Moreover, as addition mole number of alkylene oxide, 4 mol or more is preferable and 6-20 mol is more preferable.

  As content of the nonionic surfactant in a coating film peeling agent, 0-5 mass% is preferable. Even when a nonionic surfactant in an amount exceeding the upper limit is contained, no further penetration effect is observed, and the peelability of the resin coating film tends to be difficult to improve. Moreover, in order to fully obtain the addition effect of a nonionic surfactant, it is preferable that content of a nonionic surfactant is 1 mass% or more.

  The coating film remover may contain a glycol solvent such as diethylene glycol. Such a glycol solvent acts as a peeling aid when the resin coating film is peeled off. Although there is no restriction | limiting in particular as content of the glycol type solvent in a coating film peeling agent, 0-20 mass% is preferable.

  The coating film removing step according to the present invention removes the resin coating film from the crushed material by bringing the crushed material of an automotive exterior member having a PP resin molded body and a resin coating film into contact with the coating film release agent. It is a process to do. At this time, when a primer layer is formed between the PP resin molded body and the resin coating film, the primer layer is also removed together with the resin coating film.

  Although there is no restriction | limiting in particular as temperature of such a peeling process, 20-130 degreeC is preferable and 60-90 degreeC is more preferable. In this invention, since the coating film release agent containing the component mentioned above is used, it becomes possible to peel a resin coating film and a primer layer from PP resin molding at such a comparatively low temperature. That is, in the present invention, it is not necessary to perform the peeling treatment at a temperature exceeding the upper limit, and it is possible to achieve environmental considerations, workability improvement, and cost reduction. On the other hand, when the conventional coating film remover was used, it was necessary to perform the peeling treatment at a higher temperature. In addition, in this invention, when peeling process temperature becomes less than the said minimum, it exists in the tendency for the time required to peel a resin coating film and a primer layer completely.

  Moreover, there is no restriction | limiting in particular as time of the said peeling process, However, 10-60 minutes are preferable and 15-30 minutes are more preferable. In this invention, since the coating film release agent containing the component mentioned above is used, it becomes possible to peel a resin coating film and a primer layer from PP resin molding in such a comparatively short time. That is, in the present invention, it is not necessary to perform the peeling treatment over a time exceeding the upper limit, and it is possible to improve workability and reduce costs. On the other hand, when a conventional coating film peeling agent is used, it is necessary to perform the peeling treatment over a longer time. In the present invention, when the peeling treatment time is less than the lower limit, the temperature required for completely peeling the resin coating film and the primer layer tends to increase.

  The coating film removing step according to the present invention is a step of removing the resin coating film from the crushed material by bringing the crushed material of the automotive exterior member into contact with the coating film release agent (chemical means). However, it is preferable to remove the resin coating film using a physical means when or after the resin coating film is removed using the chemical means, the chemical means and the physical means, It is more preferable to carry out simultaneously. Thereby, it exists in the tendency which the peelability of a resin coating film improves dramatically. Examples of means for physically removing the resin coating from the crushed material include ultrasonic treatment, blast treatment, and shear friction treatment. These treatments may be used alone or in combination of two or more. May be.

<Granulation process>
The granulation step according to the present invention collects the crushed material from which the resin coating film and the primer layer have been removed in the coating film removal step (that is, the pulverized PP resin molded product), and is washed with water as necessary. This is a step of producing PP resin pellets after the drying treatment.

  In this granulation step, the pulverized PP resin molded body is usually pulverized, and the PP resin pulverized product is melted to produce PP resin pellets. Although there is no restriction | limiting in particular as a magnitude | size of the said PP resin ground material, It is preferable to grind | pulverize so that an average particle diameter may be 15 mm or less. If the average particle size of the pulverized PP resin exceeds the upper limit, the PP resin may not be uniformly melted when pelletized. In addition, there is no restriction | limiting in particular as a lower limit of the average particle diameter of the said PP resin ground material, Usually, it is 5 mm or more.

  In the present invention, the PP resin pellet production method and production conditions can be applied without changing (preferably as it is) the method and conditions for producing pellets from a PP resin virgin material. For example, the PP resin pulverized material produced as described above is heated and melted at 180 to 200 ° C. using a melt kneader such as an extruder, and this PP resin melt is extruded from a die to produce a strand. PP resin pellets can be obtained by cutting this using a pelletizer or the like. At this time, if necessary, various additives such as rubber components such as ethylene-propylene copolymer rubber and ethylene-propylene-diene copolymer rubber, fillers, pigments, antioxidants, ultraviolet absorbers, and heat stabilizers. Can be blended.

<Molding process>
The molding step according to the present invention is a step of producing a PP resin molded body from the PP resin pellets produced in the granulation step. In the present invention, the production method and production conditions of the PP resin molded product can be applied without changing (preferably as it is) the known production method and production conditions of the PP resin molded product. For example, the PP resin pellets obtained in the granulation step are dried as necessary, and then heated to 200 to 220 ° C. and molded by various molding methods (for example, extrusion molding, injection molding, foam molding). Thus, a recycled PP resin molded body can be obtained.

  The thus-obtained recycled PP resin molded article has a sufficiently reduced decrease in the physical properties of the PP resin, and in particular has the same Charpy impact strength as a molded article made from a PP resin virgin material. It can be used as an automobile exterior member such as an automobile bumper.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example. Table 1 shows the types of the resin coating film and the primer layer (the types of the painted resin paint and the primer) of the PP resin automotive exterior member used in the examples and comparative examples.

Example 1
The automobile exterior members 1 to 5 each having the resin coating film and the primer layer shown in Table 1 were cleaved to prepare crushed materials A-1 to A-5 (length 10 mm × width 10 mm × thickness 2 mm). Moreover, it mixed with 40 mass parts of butyl cellosolve, 40 mass parts of d-limonene, 15 mass parts of formic acid, and 5 mass parts of ethylene oxide 6 mol adducts of decanol, and prepared the coating film peeling agent.

  30 g of this coating film peeling agent was weighed into a conical stoppered flask with a capacity of 100 ml, and each of the crushed materials A-1 to A-5 was put into each piece, and then left to stand at 90 ° C. for 10 minutes to perform a peeling treatment. It was. Thereafter, the flask was cooled to room temperature, and each crushed material was taken out and collected.

(Example 2)
The amount of butyl cellosolve was changed to 45 parts by mass, and a coating film release agent was prepared in the same manner as in Example 1 except that the decanol ethylene oxide 6 mol adduct was not mixed. The crushed material was collected.

(Example 3)
A film remover in the same manner as in Example 1, except that 40 parts by mass of benzyl alcohol was used instead of d-limonene and 5 parts by mass of 7 mol of ethylene oxide adduct of decanol was used instead of 6 mol of ethylene oxide of decanol. Was prepared. Exfoliation treatment was performed in the same manner as in Example 1 except that the coating temperature was changed to 60 ° C. and the treatment time was changed to 60 minutes, and each crushed material was recovered after cooling.

Example 4
Exfoliation treatment was performed in the same manner as in Example 3 except that the treatment temperature was changed to 90 ° C. and the treatment time was changed to 30 minutes, and each crushed material was recovered after cooling.

(Example 5)
The amount of butyl cellosolve was changed to 45 parts by mass, and a coating film release agent was prepared in the same manner as in Example 4 except that the 7 mol adduct of dodecanol in ethylene oxide was not mixed. The crushed material was collected.

(Comparative Examples 1-5)
Except for using only butyl cellosolve (Comparative Example 1), d-limonene (Comparative Example 2), benzyl alcohol (Comparative Example 3), formic acid (Comparative Example 4) or N-methylpyrrolidone (Comparative Example 5) as the coating film release agent. Prepared a coating film release agent in the same manner as in Example 1, performed a peeling treatment, and recovered each crushed material after cooling.

(Comparative Example 6)
A coating film peeling agent was prepared in the same manner as in Example 1 except that only cyclohexanone was used as the coating film peeling agent. Exfoliation treatment was carried out in the same manner as in Example 1 except that the coating temperature was changed to 60 ° C. and the treatment time was changed to 600 minutes, and each crushed material was recovered after cooling.

(Comparative Examples 7-12)
80 parts by mass of heptafluorocyclopentane (Comparative Example 7), methylene chloride (Comparative Examples 8 and 11), chloroform (Comparative Examples 9 and 12) or 1-bromopropane (Comparative Example 10), 15 parts by mass of formic acid, and decanol An ethylene oxide 6 mol adduct (Comparative Examples 7, 9, 10, 12) or 5 parts by mass of dodecanol ethylene oxide 7 mol adduct (Comparative Examples 8, 11) was mixed to prepare a coating film release agent. Peeling was performed in the same manner as in Example 1 except that the coating temperature was changed to 25 ° C. (Comparative Examples 7 to 10) or 60 ° C. (Comparative Examples 11 to 12) and the processing time was changed to 60 minutes. The crushed material was collect | recovered after processing and cooling.

(Example 6)
The exterior members 1 to 5 including the resin coating film and the primer layer shown in Table 1 were each cut to prepare crushed materials B-1 to B-5 each having a length of 30 mm, a width of 30 mm, and a thickness of 2 mm. Further, 40 parts by mass of butyl cellosolve, 40 parts by mass of benzyl alcohol, 15 parts by mass of formic acid, and 5 parts by mass of an adduct of 7 mol of ethylene oxide of dodecanol were mixed to prepare a coating film release agent.

  90 g of this coating film release agent was weighed into a cylindrical metal container with a capacity of 400 ml, each of the crushed materials B-1 to B-5 was put in one piece, and an alumina ball (diameter 2 mm) was apparently 200 ml in apparent capacity. The metal lid was installed.

  The metal container was peeled by rotating it in the circumferential direction at a rotational speed of 30 rpm in a 60 ° C. hot bath for 30 minutes. Thereafter, the metal container was cooled to room temperature, the contents were taken out, and each crushed material was collected.

(Example 7)
Exfoliation treatment was performed in the same manner as in Example 6 except that the input amount of alumina balls (diameter 2 mm) was changed to an apparent volume of 120 ml, and each crushed material was recovered after cooling.

(Example 8)
The coating film was peeled off in the same manner as in Example 6 except that 40 parts by mass of d-limonene was used instead of benzyl alcohol, and 5 parts by mass of 6 mol adduct of decanol ethylene oxide was used instead of 7 mol adduct of ethylene oxide of dodecanol. An agent was prepared, a peeling treatment was performed, and each crushed material was recovered after cooling.

Example 9
Exfoliation treatment was performed in the same manner as in Example 8 except that the input amount of alumina balls (diameter 2 mm) was changed to an apparent volume of 120 ml, and each crushed material was recovered after cooling.

(Example 10)
The amount of butyl cellosolve was changed to 45 parts by mass, and a coating film release agent was prepared in the same manner as in Example 8 except that 6 mol adduct of decanol in ethylene oxide was not mixed. The crushed material was collected.

(Example 11)
Exfoliation treatment was performed in the same manner as in Example 6 except that the treatment temperature was changed to 90 ° C., and each crushed material was recovered after cooling.

(Example 12)
Exfoliation treatment was performed in the same manner as in Example 11 except that the input amount of alumina balls (diameter 2 mm) was changed to an apparent volume of 280 ml, and each crushed material was recovered after cooling.

(Example 13)
The amount of butyl cellosolve was changed to 45 parts by mass, and a coating film release agent was prepared in the same manner as in Example 11 except that the 7 mol adduct of dodecanol in ethylene oxide was not mixed. The crushed material was collected.

(Examples 14 to 15)
Exfoliation processing was performed like Example 8-9 except having changed processing temperature to 90 ° C, and after crushing, each crushed material was collect | recovered.

(Comparative Examples 13 to 16)
Coating film in the same manner as in Example 11 except that only butyl cellosolve (Comparative Example 13), d-limonene (Comparative Example 14), benzyl alcohol (Comparative Example 15) or formic acid (Comparative Example 16) was used as the coating film release agent. A release agent was prepared, a release treatment was performed, and each crushed material was recovered after cooling.

<Peeling degree>
The coated surface of each crushed material collected in Examples and Comparative Examples was visually observed, and the degree of peeling between the resin coating film and the primer layer was determined according to the following criteria. The results are shown in Tables 2-5.
A: The resin coating film and the primer layer did not remain on the painted surface, and the remaining rate was 0%.
B: Although the resin coating film and the primer layer remained very slightly on the painted surface, the remaining rate was less than 5%.
C: The resin coating film and the primer layer remained on the painted surface, and the remaining rate was 5% or more and less than 35%.
D: Resin coating film and primer layer remained on the painted surface, and the remaining rate was 35% or more and less than 50%.
E: The resin coating film and the primer layer remained on the painted surface, and the remaining rate was 50% or more and less than 100%.
F: The resin coating film and the primer layer remained on the entire painted surface, and the remaining rate was 100%.

  As is clear from the results shown in Table 2, the coating film stripper (Examples 1 to 5) containing butyl cellosolve, d-limonene or benzyl alcohol, and formic acid is excellent for any crushed material. It was confirmed that the coating film peelability was exhibited. Moreover, when the coating film peeling agent containing a nonionic surfactant is used (Examples 1 and 3 to 4), the coating film peelability is improved as compared with the case where a nonionic surfactant is not contained. I understood it. On the other hand, when any one of butyl cellosolve, d-limonene, benzyl alcohol, and formic acid is used as a coating remover (Comparative Examples 1 to 4) or N-methylpyrrolidone is used (Comparative Example 5). It has been found that the peeling of the coating film has selectivity, and in particular, the peeling property of the aqueous resin coating film is inferior. That is, the coating film peeling agent according to the present invention can peel the coating film even when different types of resin coating films are mixed, whereas the coating film peeling agent used in Comparative Examples 1 to 5 is used. When using, it turned out that the exterior member for motor vehicles needs to be classified beforehand for every kind of resin coating film.

  Further, as is clear from the results shown in Table 3, when a peeling treatment was performed at 25 ° C. using a halogen-based solvent as a coating film peeling agent (Comparative Examples 7 to 10), it was selected for peeling the coating film. It was found that the peelability of the aqueous resin coating film was particularly poor. In addition, when the stripping process is performed using a halogen-based solvent, a facility for processing the halogen in the drainage is necessary. On the other hand, when the peeling treatment was performed at 60 ° C. using a coating film release agent containing methylene chloride or chloroform (Comparative Examples 11 to 12), excellent film peeling properties were obtained for any crushed material. It turns out that it is obtained. However, as in Comparative Examples 11 to 12, when the peeling treatment is performed at 60 ° C. using a halogen-based solvent, not only the equipment for treating the halogen in the drainage but also the halogen-based solvent is diffused into the atmosphere. Therefore, equipment for recovering it was also necessary.

  As is clear from the results shown in Table 4, when the peeling treatment using the coating film peeling agent according to the present invention and the physical peeling treatment (treatment with an alumina ball) are used in combination (Examples 6 to 15) In addition, it was confirmed that excellent peelability was obtained for any crushed material. In particular, when compared with the results shown in Table 2 (Examples 1 to 5), it was confirmed that the coating film peelability was improved by using a physical peeling treatment in combination.

  On the other hand, as is apparent from the results shown in Table 5, a peeling treatment using any one of butyl cellosolve, d-limonene, benzyl alcohol, and formic acid and a physical peeling treatment (treatment with an alumina ball) are used in combination. When it did (Comparative Examples 13-16), it turned out that there exists selectivity in peeling of a coating film, and especially the peelability of an aqueous resin coating film is inferior. Moreover, the effect which used physical peeling processing together was hardly seen. That is, for the coating film release agent according to the present invention, the coating film can be easily peeled even when different types of resin coating films coexist with the physical peeling treatment. As for the coating film release agents used in Comparative Examples 13 to 16, it was found that it is necessary to separate the automotive exterior member in advance for each type of resin coating film even when using a physical peeling treatment. .

<Physical property evaluation of recycled PP resin molding>
The crushed material from which the coating film was removed in the examples was washed with water and pulverized to an average particle diameter of 15 mm, and then granulated to produce PP resin pellets. The PP resin pellets were dried at 100 ° C. for 3 hours. The melt flow rate of the dried PP resin pellets was measured by the following method. In addition, using the dried PP resin pellets, injection molding was performed at a molten resin temperature of 200 ° C. and a mold temperature of 40 ° C., and type A multipurpose test pieces were produced in accordance with ISO 3167. The parallel part of this multi-purpose test piece is cut out to produce a bar-type test piece (length 80 mm × width 10 mm × thickness 4 mm), and the physical properties of the recycled PP resin molded product are measured by the following method using the bar-type test piece. It was measured.

(Melt flow rate)
In accordance with the method described in ISO 1133, the melt flow rate of the recycled PP resin was measured under the conditions of load: 21.18 N and test temperature: 230 ° C.

(Tensile modulus)
In accordance with the method described in ISO 527-1, 2, a tensile test was performed under the conditions of a tensile speed: 50 mm / min, a distance between chucks: 115 mm, and a test environment: 23 ± 2 ° C. The elastic modulus was determined.

(Charpy impact strength)
A notch of type A having a radius of 0.25 mm was processed on the bar-type test piece so that the remaining width was 8.0 mm to prepare a notched test piece. Using this notched test piece, the Charpy impact strength of the recycled PP resin molding was measured at a test temperature of −30 ° C. or 23 ° C. by an edgewise test method in accordance with ISO 179-1,2.

(Brittle temperature)
The embrittlement temperature of the recycled PP resin molded product was measured according to ASTM D746-98.

(Load deflection temperature)
The deflection temperature of the recycled PP resin molded body at a bending stress of 1.8 MPa or 0.45 MPa was measured by the flatwise method in accordance with ISO 75-1 to 3-1.

(Rockwell hardness)
Based on the method described in ISO 2039-2, the Rockwell hardness of the recycled PP resin molding was measured.

  Table 6 shows various physical property values of the recycled PP resin recovered by removing the coating film from the crushed material A-5 or B-5 and the molded product thereof in Example 1 or 6. Table 6 also shows various physical property values of the recycled PP resin molded body (unremoved recycled product) produced from the crushed material A-5 from which the PP resin virgin material or resin coating film was not removed.

  As is apparent from the results shown in Table 6, the physical properties of the recycled PP resin obtained from the crushed material from which the coating film has been removed and the molded product thereof are comparable to those of the PP resin virgin material and the molded product. It was confirmed that it was superior to the recycled product.

  As described above, according to the present invention, a polypropylene resin automotive exterior member can be regenerated without deteriorating the physical properties of the resulting polypropylene resin molded article, and is coated with a solvent-based paint. Even when a polypropylene resin automotive exterior member and a polypropylene resin automotive exterior member coated with a water-based paint are mixed, it is possible to reproduce them without sorting them.

  Therefore, the method for producing a recycled polypropylene resin molded product of the present invention is such that the physical properties of the obtained polypropylene resin molded product satisfy the physical properties required for automotive exterior members such as automotive bumpers. This is useful as a method for reusing a polypropylene resin automotive exterior member such as an automotive bumper.

Claims (5)

Contacting a crushed automobile exterior member comprising a polypropylene resin molded article and a resin coating film, and a coating film release agent containing at least one of d-limonene and benzyl alcohol, butyl cellosolve and formic acid, Removing the resin coating film from the crushed material;
Recovering the crushed material after removing the coating film to produce polypropylene resin pellets;
Producing a polypropylene resin molded article using the polypropylene resin pellets;
The manufacturing method of the reproduction | regeneration polypropylene-type resin molded object characterized by including.   The recycled polypropylene resin molding according to claim 1, wherein the resin coating film is physically removed from the crushed material when or after the crushed material and the coating film release agent are brought into contact with each other. Body manufacturing method. The automobile exterior member further includes a primer layer between the resin coating film and the polypropylene resin molded body,
The method for producing a recycled polypropylene resin molded article according to claim 1 or 2, wherein the primer layer is removed from the crushed material together with the resin coating film.   The method for producing a recycled polypropylene-based resin molded article according to any one of claims 1 to 3, wherein the coating film release agent further contains a nonionic surfactant.   The method for producing a recycled polypropylene resin molded body according to any one of claims 1 to 4, wherein the recycled polypropylene resin molded body is an automotive exterior member.