Resin molded body and method for producing the same

Abstract

The present invention comprises a base material which includes a resin, a first coating film which is formed on a surface of the base material and the thickness of which is 100-1,000 micrometers, and a second coating film which is formed on a surface of the first coating film and the thickness of which is 100-1,000 micrometers.

Description

[Technical field]

[0001] The present disclosure relates to a resin molded article and a method for producing the resin molded article. [Background technology]

[0002] Conventionally, there has been known a coating method for forming a coating layer on a resin molded body inside a mold for molding the resin molded body (see, for example, Patent Document 1). This type of coating method is called an in-mold coating method, and is known as an environmentally friendly coating method that can reduce the use of volatile organic compounds.

[0003] Also known is a resin molding method in which two types of resin materials are integrated together using a core-back type injection molding machine (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-76174 A [Patent Document 2] JP 2005-88527 A Summary of the Invention [Problem to be solved by the invention]

[0005] The in-mold coating method of Patent Document 1 does not disclose the formation of two coating layers. Furthermore, Patent Document 2 discloses a method for integrating two resin layers, but does not disclose a method for forming the coating layers.

[0006] The present disclosure provides a resin molded article having a plurality of coating layers formed thereon using an in-mold coating method, and a method for producing the resin molded article. [Means for solving the problem]

[0007] The resin molded body according to the present disclosure comprises a substrate containing a resin, a first coating layer having a thickness of 100 micrometers or more and 1000 micrometers or less formed on a surface of the substrate, and a second coating layer having a thickness of 100 micrometers or more and 1000 micrometers or less formed on the surface of the first coating layer.

[0008] In addition, the manufacturing method of a resin molded body according to the present disclosure includes a step of injecting a resin material into a cavity formed by a first mold and a second mold to form a substrate, a first coating step of opening the first mold and the second mold, injecting a first coating film forming material between the substrate and the first mold, and forming a first coating film layer on a surface of the substrate, and a second coating step of opening the first mold and the second mold again, injecting a second coating film forming material between the first coating film layer and the first mold, and forming a second coating film layer on the surface of the first coating film layer. Effect of the Invention

[0009] In this resin molded body, the first coating layer has a thickness corresponding to a coating layer formed by an in-mold coating method, and the second coating layer also has a thickness corresponding to a coating layer formed by an in-mold coating method.

[0010] Moreover, according to such a method for producing a resin molded article, the first coating layer and the second coating layer can be formed by an in-mold coating method. [Brief description of the drawings]

[0011] [Figure 1] Side view of resin molded body [Diagram 2] Cross section AA of Figure 1 [Diagram 3] 1 is a schematic diagram of a mold device used in an in-mold coating method. [Figure 4] FIG. 1 shows a method for manufacturing a resin molded body. [Diagram 5] FIG. 2 shows a method for manufacturing a resin molded body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] As shown in Figs. 1 and 2, the resin molded body 1 includes a substrate 2, a first coating layer 4, and a second coating layer 6. In this embodiment, the resin molded body 1 is a resin member used as a decorative panel for the interior of an automobile, a bumper, or the like. The resin molded body 1 has a front surface 1a and a back surface 1b. When the resin molded body 1 is an interior member of an automobile, the front surface 1a of the resin molded body 1 is assembled so as to face the automobile user. When the resin molded body 1 is an exterior member of an automobile, the front surface 1a of the resin molded body 1 is disposed so as to face the outside of the automobile.

[0014] The substrate 2 is a resin member that serves as a base for forming the first coating layer 4. The substrate 2 is made of a thermoplastic resin material. Examples of the resin material include polypropylene, polyethylene, ABS resin (acrylonitrile-butadiene-styrene copolymer), PC resin (polycarbonate resin), etc.

[0015] The first coating layer 4 is a coating layer formed on the surface 1a side of the substrate 2. More specifically, the first coating layer 4 is formed by a material for forming a first coating film that is attached to the surface of the substrate 2 by an in-mold coating method. The material for forming the first coating film may include a paint suitable for the in-mold coating method described in, for example, JP-A-6-107750 and JP-A-8-113761. In addition, in this embodiment, the first coating layer 4 is a color layer formed by a paint containing a coloring agent. The first coating layer 4 may include a so-called glittering material consisting of metal pieces, mica pieces, glass beads, and the like. The thickness of the first coating layer 4 formed by the in-mold coating method is 100 micrometers or more and 1000 micrometers or less.

[0016] The first coating layer 4 is a coating layer containing a release agent and / or having a release agent attached to its surface. That is, the paint for the first coating layer 4 may contain a release agent. The paint for the first coating layer 4 may not contain a release agent component, and the release agent sprayed onto the mold may be laminated on the coating surface. The release agent is a chemical agent that suppresses the first coating layer 4 from adhering to the first mold 22 (see FIG. 3) described later. The release agent makes it easy for the molded product to be separated from the mold. In this embodiment, the release agent is, for example, a chemical agent containing light naphtha or wax. The wax is, for example, paraffin wax and micro wax. In addition, the release agent may contain polydimethylsiloxane. The second coating layer 6 described later is formed with the release agent attached to the surface of the first coating layer 4 formed by the in-mold coating method.

[0017] The second coating layer 6 is a coating layer formed on the surface of the first coating layer 4. The second coating layer 6 includes a paint in which two different second coating forming materials are mixed and cured. In this embodiment, the paint forming the second coating layer 6 is a urethane paint in which polyol (an example of a first material) and isocyanate (an example of a second material) are mixed, reacted, and cured. However, the second coating layer 6 may be a paint other than a urethane paint, so long as it includes a paint in which two or more different materials are mixed and cured. The curing includes curing by reaction of mixing different materials, and curing by lowering the temperature after mixing two different materials.

[0018] In this embodiment, the second coating layer 6 is a clear layer that is a transparent coating that covers the first coating layer 4. The clear layer has a function of adding gloss to the color of the first coating layer 4. The clear layer also has a function of protecting the first coating layer 4. For this reason, in this embodiment, the second coating layer 6 is formed of a paint that does not contain a colorant, or a translucent paint that contains a colorant. However, the second coating layer 6 may be any paint as long as it is a paint in which two different materials are mixed and hardened.

[0019] The thickness of the second coating layer 6 is 100 micrometers or more and 1000 micrometers or less. In this embodiment, the thickness of the clear layer which is the second coating layer 6 is set to be equal to or thinner than the thickness of the color layer which is the first coating layer 4.

[0020] Next, a method for manufacturing the resin molded body 1 will be described with reference to Figures 3, 4, and 5. As shown in Figure 3, in this embodiment, a mold apparatus 20 used in the in-mold coating method is a resin injection molding apparatus including a first mold (an example of a first mold) 22, a second mold (an example of a second mold) 24, a resin injector 26, and a paint injector 28. The first mold 22 and the second mold 24 form a cavity 30 by closing the mold. However, the mold apparatus 20 may be any mold as long as the in-mold coating method is possible.

[0021] The resin injector 26 is a nozzle for injecting a resin material for forming the substrate 2 (see FIG. 2). In this embodiment, the resin injector 26 is disposed on the second mold 24 side of the cavity 30. The resin injector 26 may be disposed facing the supply passage 30a. The supply passage 30a is connected to the cavity 30. The paint injector 28 is a nozzle for injecting the first coating film forming material and the second coating film forming material. In this embodiment, the paint injector 28 is disposed on the first mold 22 side of the cavity 30.

[0022] First, as shown in FIG. 4(a), a resin material is injected from the resin injector 26 into the cavity 30 to form the substrate 2. Thereafter, the mold device 20 is opened and the second mold 24 is separated from the first mold 22, so that the first mold 22 is separated from the substrate 2. Furthermore, a release agent is applied to the surface of the first mold 22 facing the cavity 30, and a layer of the release agent is formed. If the first coating film forming material contains a release agent, the application process of the release agent may be omitted. If the first coating film forming material does not contain a release agent, the release agent may be applied to the surface of the first mold 22 and / or the second mold 24 facing the cavity 30 before the substrate 2 is formed.

[0023] 4(b), when forming the first coating layer 4, the second mold 24 is separated from the first mold 22 so that the distance between the first mold 22 and the substrate 2 is 100 micrometers or more and 1000 micrometers or less. The material for forming the first coating film is injected into the gap between the first mold 22 and the substrate 2 via the paint injector 28 (first coating process). At this time, the first mold 22 and / or the second mold 24 may be heated so that the material for forming the first coating film can flow easily.

[0024] As shown in FIG. 4(c), when the first coating layer 4 is formed, the first mold 22 is moved toward the second mold 24, and the first coating layer 4 is compressed (see the white arrow in FIG. 4(c)) (first compression step). This allows the first coating layer 4 to be adhered to the substrate 2. Furthermore, the surface of the first mold 22 can be transferred to the first coating layer 4. In addition, by compressing the first coating layer 4, it is possible to prevent sink marks from occurring on the surface of the first coating layer 4 due to shrinkage when the first coating layer 4 is cured. At this time, it is preferable that the first distance by which the first mold 22 is moved toward the second mold 24 is changed depending on the thickness of the first coating layer 4. It is preferable that the first distance is larger as the thickness of the first coating layer 4 becomes thicker. This makes it easier to adhere the first coating layer 4 to the substrate 2 even when the thickness of the first coating layer 4 is thick. The same applies to the second coating layer 6 described later.

[0025] Next, as shown in FIG. 5(a), the mold device 20 is opened again so that the first mold 22 is at a distance of 100 micrometers to 1000 micrometers from the surface of the first coating layer 4 (see the white arrow in FIG. 5(a)). Then, as shown in FIG. 5(b), a second coating film forming material containing two different materials for forming the second coating layer 6 is injected into the cavity 30 (second coating process). At this time, the two different materials are mixed at the tip of the paint injector 28 and injected. The two injected materials react and harden while flowing on the surface of the first coating layer 4 as paint.

[0026] As shown in FIG. 5(c), when the paint hardens, the first mold 22 is moved toward the second mold 24, and the second coating layer 6 is compressed (see the white arrow in FIG. 5(c)) (second compression step). In this embodiment, the thickness of the second coating layer 6 is set to be equal to or thicker than the thickness of the first coating layer 4. Therefore, the second distance by which the first mold 22 is moved when the second coating layer 6 is compressed is equal to or longer than the first distance by which the first mold 22 is moved when the first coating layer 4 is compressed.

[0027] Finally, the mold device 20 is opened, the first mold 22 is separated from the second mold 24, and the resin molded body 1 is taken out.

[0028] As described above, according to such a resin molded body 1, the first coating film layer 4 and the second coating film layer 6 can be formed by the in-mold coating method. This makes it possible to reduce the use of volatile organic compounds compared to forming a coating film layer by coating. Furthermore, the second coating film layer 6 is formed on the first coating film layer 4 by the in-mold coating method. This makes it possible to form a thick coating film layer (for example, a coating film layer having a thickness of 100 micrometers or more) that cannot be formed by coating due to sagging. As a result, the durability of the resin molded body 1 is improved.

[0029] In addition, in the manufacturing method of the resin molded body 1 of this embodiment, the first coating film layer 4 and the second coating film layer 6 are compressed. This makes it possible to more firmly bond the coating film layers and make them less likely to peel off. Furthermore, the first coating film layer 4 and the second coating film layer 6 are manufactured using the same first mold 22 and second mold 24. This makes it possible to reduce manufacturing costs compared to using separate molds.

[0030] Furthermore, in the manufacturing method of the resin molded body 1 of this embodiment, the first mold 22 and the second mold 24 are not opened (i.e., the cavity 30 is not opened) until the step of removing the resin molded body 1. This prevents dust and other particles from adhering to the coating layers. As a result, the resin molded body 1 manufactured by this manufacturing method does not suffer from peeling of the coating, and is easy to maintain its good appearance.

[0031] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the invention.

[0032] For example, in the above embodiment, the resin molded body 1 is described as a member used in an automobile, but the present disclosure is not limited thereto. The resin molded body 1 may be a resin member used for something other than an automobile.

[0033] In addition, although thermoplastic resins such as polypropylene, polyethylene, ABS resin, and PC resin have been exemplified as the resin material forming the base material 2, the present disclosure is not limited thereto. The base material 2 may be, for example, a thermoplastic resin such as polyamide, polyethylene terephthalate, or modified polyphenylene ether, or an alloy material of these thermoplastic resins, or further a resin material obtained by blending fibrous or scaly filler with these thermoplastic resins. In any case, the base material 2 may be any resin as long as it is formed of a thermoplastic resin.

[0034] In the above embodiment, the first coating layer 4 and the second coating layer 6 are formed between the substrate 2 and the first mold 22, but the present disclosure is not limited to this. For example, the substrate 2 may be attached to the first mold 22 side, a gap may be formed between the second mold 24 and the substrate 2, and then a coating material may be injected to form the first coating layer 4 and the second coating layer 6 between the substrate 2 and the second mold 24. [Explanation of symbols]

[0035] 1: Resin molding 1a: surface 1b: Back side 2: Base material 4: 1st coating layer 6: 2nd coating layer 20:Molding equipment 22: First mold 24: Second mold 26: Resin injector 28: Paint injector 30: Cavity

Claims

1. A substrate including a resin; A first coating layer having a thickness of 100 micrometers or more and 1000 micrometers or less formed on the surface of the substrate; A second coating layer having a thickness of 100 micrometers or more and 1000 micrometers or less formed on the surface of the first coating layer; A resin molded body comprising:

2. The first coating layer contains a release agent and / or is a coating layer having a release agent attached to its surface. The resin molded article according to claim 1 .

3. A step of injecting a resin material into a cavity formed by the first mold and the second mold to form a substrate; a first coating step of opening the first mold and the second mold, injecting a first coating film forming material between the substrate and the first mold, and forming a first coating film layer on the surface of the substrate; a second coating step of opening the first mold and the second mold again, injecting a second coating film forming material between the first coating film layer and the first mold, and forming a second coating film layer on a surface of the first coating film layer; A method for producing a resin molded body comprising the steps of:

4. The first coating layer contains a release agent and / or is a coating layer having a release agent attached to its surface. The method for producing the resin molded article according to claim 3 .

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