JP3648901B2 - Thermosetting resin-coated thermoplastic resin molded article and method for recycling the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of reusing a plastic waste product having a surface treated such as painting as a plastic product.
[0002]
[Prior art]
In recent years, many plastic products have been used for automobile parts. For example, in the case of a plastic bumper, if the surface is not painted, a molding failure product or a product recovered from a scrap car can be roughly pulverized to about 3 mm square, mixed with a virgin material, and used again for molding a bumper. This is possible because the physical properties of the recycled plastic are hardly deteriorated. In the case of a bumper with a painted surface, if the same processing is performed, the pulverized coating film is mixed into the recycled plastic, so that the plastic material The physical properties such as impact resistance, elongation, and surface quality are greatly reduced and the performance required as a bumper cannot be satisfied, so it cannot be reused.
[0003]
[Problems to be solved by the invention]
For this reason, as a method of reclaiming plastic waste with a coating film, a method was considered in which the coating film was reduced in molecular weight by hydrolysis and finely dispersed in the base material resin. Large-scale equipment is required, resulting in high costs.
[0004]
Japanese Laid-Open Patent Publication No. 7-90107 discloses a method of reusing paint plastics by dissolving a coating film by adding a coating film decomposing agent and uniformly dispersing it in the base material resin. However, in order to contact and react with the coating film at the time of regeneration, it is unavoidable to add a larger amount than the actual coating amount. Similarly, if a coating film decomposing agent is added to a baking and drying type paint as it is, the paint may not be cured and become an uncured coating because it reacts directly with the paint resin when the paint is dried. There is. (Currently mass-produced PP bumpers are baked and dried at 120 ° C for both undercoat and topcoat)
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention applies a natural-drying type paint containing a required amount of a coating film decomposing agent to the back surface of a molded product whose surface is coated, and naturally drys it to regenerate the molded product. At the time of processing, the coating film on the surface is chemically reacted with the coating film decomposing agent contained in the coating film on the back surface portion, and is melted in the plastic material so as to make the coating film harmless. That is, the present invention intends to solve the above problems by adopting the following configuration.
[0006]
(1) A heat produced by applying a thermoplastic resin-based paint containing a necessary amount of a thermosetting resin coating film decomposing agent sufficient to decompose a coated thermosetting resin paint to the back side of the product. Thermoplastic resin molded product coated with curable resin paint.
(2) A heat produced by applying a thermoplastic resin-based paint containing a necessary amount of a thermosetting resin coating film decomposing agent sufficient to decompose the coated thermosetting resin paint to the back side of the product. After roughly pulverizing the thermoplastic resin molded article coated with the curable resin paint, the mixture is heated and mixed and kneaded, the coating film decomposing agent is melted and dispersed, reacted with the thermosetting resin coating film component, and decomposed. A method for regenerating a thermoplastic resin molded article coated with a thermosetting resin paint in which a thermosetting resin coating film component is diffused into the thermoplastic resin.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a thermoplastic resin molded product according to an embodiment of the present invention, and FIG.
[0008]
As shown in FIG. 2, the thermoplastic resin molded product 1 of the present invention is applied to a surface of a thermoplastic resin 2 such as a polyolefin-based resin or an ABS-based resin as a primer coating film 3 with a polyurethane-modified polyolefin-based resin paint, a top coating ( Base) Polyester-melamine resin paint is applied as coating film 4, and acrylic-melamine resin paint is applied as top coat (clear) coating film 5. The baking temperature of the coating is 120 ° C. for 30 minutes for both the undercoat and the topcoat.
[0009]
As shown in FIG. 1, in the thermoplastic resin molded product 6 according to the embodiment of the present invention, a natural drying type containing a coating film decomposing agent is formed on the back surface of the thermoplastic resin molded product 1 manufactured as described above. It is manufactured by applying an acrylic lacquer coating film 7. In addition, the location to which the natural drying type acrylic lacquer coating film 7 containing the coating film decomposing agent is applied is not particularly limited, but it is preferable to select a place where the flat portion is easily applied. In addition, depending on the material of the molded product, it is preferable to polish the painted portion in order to ensure the adhesion of the paint.
[0010]
Examples of the coating film decomposing agent include 2-mercaptoimidazoline, benzotriazole, 3-amino-1,2,4-triazole, 2-methylimidazole, and N-cyclohexyl as described in JP-A-7-90107. Heterocyclic compounds such as 2-benzothiazole, sulfenamide, 2-phenylimidazole, and imidazole are used.
[0011]
Similarly, 2-di-n-butylamino-4,6-dimercapto-s-triazine, 2,4,6-triallyloxy-1,3,5-triazine, benzoguanamine described in the same publication, Triazine compounds such as melamine, isomelamine, acetoguanamine, guanylmelamine, 2,4,6-trimercapto-s-triazine, triazole compound, isocyanuric acid and isocyanuric acid ester are used.
[0012]
Furthermore, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-1,3-dimethylbutyl are also described in the same publication. Phenylenediamine compounds such as -p-phenylenediamine, N, N'-di-β-naphthyl-p-phenylenediamine, N, N'-diallyl-p-phenylenediamine are used.
[0013]
The coating film decomposing agent described above is added to an air-drying acrylic lacquer-based paint (stock solution: paint before dilution). The addition amount of the coating film decomposing agent is used according to the addition amount as described in JP-A-7-90107, but in order to reduce the coating range of the back surface of the coated resin molded product, Add more than the amount added. The coating film decomposing agent to be used can be selected regardless of the solubility of the coating solvent. That is, even if a coating film decomposing agent that does not dissolve remains as a foreign substance on the coating film surface after coating, there is no problem because it is a part that does not require appearance.
[0014]
Next, in the embodiment shown in FIG. 1 according to the present invention, a thermoplastic resin having a coating film on the surface and coated with a natural drying type acrylic lacquer coating film 7 containing a coating film decomposing agent on the back side. A method for regenerating the molded product 6 will be described.
[0015]
As the processing method,
(1) First, the thermoplastic resin molded product 6 is roughly pulverized to about 1 to 10 mm square by a pulverizer.
(2) The pulverized product is mixed and kneaded with a twin screw extruder at a temperature of 160 to 200 ° C., and regenerated as pellets with a pelletizer. The coating film decomposing agent melts at a temperature of 160 to 200 ° C. and mechanical kneading, and comes into contact with the paint resin component coated on the surface to cause a reaction.
[0016]
The purpose of mixing and kneading by the above twin screw extruder is to react the coating film decomposing agent with the paint resin component, and to weakly bind the polyurethane-modified polyolefin (undercoat) with polyester-melamine (overcoat base) or acrylic-melamine (overcoat). This is because the ether bond of (clear) is cleaved and cut and melted and dispersed in a thermoplastic resin molding material such as polyolefin or ABS to prevent poor surface appearance and deterioration of physical properties due to remaining coating film pieces.
[0017]
An example of the added amount of the coating film decomposing agent is as follows (refer to the description of JP-A-7-90107 for other examples).
For those in which a chlorinated polyolefin resin is applied to a polypropylene resin as a primer at a thickness of about 25 μm and a polyester melamine resin is applied as a top coating to a thickness of about 30 μm, a benzotriazole as a coating film decomposing agent is 0.5 to Good results have been obtained with the addition of 1.5% by weight.
[0018]
【The invention's effect】
According to the present invention, the coating film decomposing agent for completely dissolving the coating film and uniformly mixing and dispersing it in the plastic is applied to the back side surface of the molded product so that the regeneration can be easily performed. Regeneration can be performed reliably in the case of recycling, the loss of coating film decomposing agent is eliminated, coating uncured during paint baking and drying is prevented, and when plastic is recycled, the coating contained in the back coating film The film decomposing agent decomposes the paint film on the surface of the molded product and disperses it uniformly in the plastic, and does not adversely affect the physical properties and surface quality of the plastic to be reused.
[0019]
In addition, it is not necessary to select painted resin parts and unpainted resin parts when recycling plastics, and the recycling cost can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a thermoplastic resin molded article according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a coating of a thermoplastic resin molded product targeted for the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Thermoplastic resin molding object of this invention implementation 2 Thermoplastic resin of polyolefin type, ABS type, etc. 3 Undercoat paint film 4 Topcoat paint (base) paint film 5 Topcoat paint (clear) paint film 6 Heat according to the embodiment of the present invention Plastic resin molding 7 Natural dry acrylic lacquer coating film containing paint film decomposing agent

Claims (2)

A thermosetting resin that is formed by applying a thermoplastic resin-based paint containing a necessary amount of a thermosetting resin coating film decomposing agent to decompose the coated thermosetting resin paint to the back side of the product. Thermoplastic resin molded product with paint applied. A thermosetting resin that is formed by applying a thermoplastic resin-based paint containing a necessary amount of a thermosetting resin coating film decomposing agent to decompose the coated thermosetting resin paint to the back side of the product. After roughly pulverizing the thermoplastic resin molded product coated with paint, heat mixing and kneading, melting and dispersing the coating film decomposing agent, reacting with the thermosetting resin coating film component, decomposing it, and thermosetting A method for regenerating a thermoplastic resin molded article coated with a thermosetting resin paint in which a resin coating film component is diffused in a thermoplastic resin.

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