Painting structure for resin molded body and painting method thereof

Abstract

The objective is to create a coating structure for resin molded articles and a coating method thereof that can more effectively impart a water droplet pattern, which enhances the aesthetic appeal, to transparent resin molded articles such as PET resin. [Solution] A coating structure for a resin molded body, wherein the surface of the resin molded body 1 is laminated in order from the bottom to the top, with at least a first primer layer 11 forming a base layer, a first UV matte layer 12, a printing layer 13, and a UV splash layer 14 forming a water droplet pattern P.

Description

Technical Field

[0001] The present invention relates to a coating structure of a resin molded body composed of a synthetic resin container or the like and a coating method thereof.

Background Art

[0002] On the surface of a compact container (a molded body made of synthetic resin) (the surface of the base material layer), a preliminary pattern (printing layer) such as characters, patterns, colors, etc. is applied by printing or hot stamping in advance, an ultraviolet curable paint is applied and a film (protective layer) cured by ultraviolet irradiation is formed, and further, an ultraviolet curable paint the same as or different in color from the above paint is adhered in a fine particle state by spray coating on this film and cured by ultraviolet irradiation to expose a water droplet pattern (UV (Ultraviolet, the same hereinafter) decorative layer). A method for manufacturing a decorative article is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of the structure described in Patent Document 1 above, the layer structure for decoration formed on the base material layer is a three-layer structure of a printing layer, a protective layer, and a UV decorative layer. However, when the base material layer is a transparent resin such as PET (POLY ETHYLENE TEREPHTHALATE) resin, a printing layer is directly formed on the base material layer, and problems such as being easily peeled off are likely to occur.

[0005] Therefore, the inventor of the present invention formed a primer layer (undercoat) on a base layer, then formed a UV matte layer (matte layer) consisting of a matte paint containing an ultraviolet curing agent on top of that, cured it with ultraviolet light, and then formed a printing layer. Subsequently, a UV splash coating was applied to the surface of the UV matte layer including the printing layer, and then cured with ultraviolet light to form a UV decorative layer consisting of a water droplet pattern.

[0006] However, when a UV-cured decorative layer is formed by UV splash coating on top of a UV-cured matte layer, and then UV-cured, there is a problem in that the adhesion between the UV matte layer and the UV decorative layer becomes low.

[0007] Furthermore, when a primer layer was formed after the printed layer, and then UV splash coating was applied and cured with ultraviolet light to form the UV decorative layer, a portion of the primer layer was exposed, resulting in a significant deterioration of physical properties such as scratch resistance.

[0008] The present invention aims to create a coating structure for a resin molded article and a coating method thereof that can more effectively impart a water droplet pattern, which enhances the aesthetic appeal, to a transparent resin molded article such as a PET resin, in order to solve the problems of the conventional technology described above. [Means for solving the problem]

[0009] Among the means for solving the above problems, the first means of the present invention is: A coating structure for a resin molded body, The resin molded body is characterized in that, on its surface, a first primer layer forming at least a base layer, a first UV matte layer, a printing layer, and a UV splash layer forming a water droplet pattern are sequentially laminated from the bottom to the top.

[0010] In the first method described above, since the printed layer does not need to be formed directly on the substrate layer, it can be made less prone to peeling, and since the first UV matte layer covers the first primer layer and prevents it from being exposed, it is possible to improve scratch resistance and other properties.

[0011] Furthermore, the second means of the present invention adds to the first means described above that a second primer layer and a second UV matte layer are laminated between the printed layer and the UV splash layer, from the bottom layer to the top layer. The above method can enhance protection for the printed layer.

[0012] Furthermore, a third means of the present invention adds to the first or second means described above, the first primer layer being formed of a polyester-based primer obtained by mixing a diluted thinner with the primer, or a heat-drying paint obtained by mixing a pigment with the polyester-based primer; the first UV matte layer being formed of a UV paint containing an acrylic-based UV matte paint, a matting agent for matting, and a predetermined pigment; the printing layer being formed of characters, figures, or symbols using ink, metallic foil (vacuum-deposited foil), or pigment foil (coated foil), or a combination thereof; and the UV splash layer being formed of a UV paint for glossing made of acrylic-based UV clear.

[0013] Furthermore, a fourth means of the present invention adds to the second means described above, the second primer layer being formed of a hot-drying paint obtained by mixing a chlorinated polyolefin-based primer with a diluted thinner and a polyolefin-based primer, and the second UV matte layer being formed of an acrylic UV paint containing a matting agent in an acrylic UV matte paint.

[0014] Furthermore, a fifth means of the present invention is a method for coating a painted structure of a resin molded article, The invention is characterized by comprising at least the following steps: a first step of spraying a first primer paint onto the surface of the resin molded body and then drying it with far-infrared rays to form a first primer layer; a second step of spraying a first UV matte paint onto the surface of the first primer layer and then drying it with far-infrared rays to form a first UV matte layer; a third step of forming a printed layer on the surface of the first UV matte layer; a fourth step of applying a UV splash paint to the surfaces of the first UV matte layer and the printed layer to create a polka-dot pattern; and an ultraviolet irradiation step of curing all UV paints by irradiating them with ultraviolet light. In the fifth method of the present invention, the adhesion between the UV matte layer and the UV splash layer can be strengthened by irradiating them with ultraviolet light at the same time.

[0015] Furthermore, the sixth means of the present invention is that, in addition to the fifth means described above, a fourth step is to form a second primer layer by spraying a second primer paint onto a first UV matte layer which includes a printed layer on a part of its surface, and then drying it with far-infrared rays, between the third step and the ultraviolet irradiation step, and a fifth step is to form a second UV matte layer by spraying a second UV matte paint onto the surface of the second primer layer and then drying it with far-infrared rays.

[0016] Furthermore, the seventh means of the present invention adds to the fifth or sixth means described above that the fourth step is a step of applying UV splash paint using a low-pressure spray gun. The above method allows the UV splash layer to be constructed in a droplet pattern. [Effects of the Invention]

[0017] This invention makes it possible to improve scratch resistance and other properties, and to enhance the aesthetic appeal of the water droplet pattern. Furthermore, since it is possible to improve the adhesion between the UV matte layer and the UV splash layer that forms the water droplet pattern, the aesthetic appeal of the water droplet pattern can also be enhanced from this perspective. [Brief explanation of the drawing]

[0018] [Figure 1] It is a half cross-sectional view of a container provided with a coating structure of a resin molded body according to the present invention. [Figure 2] It is an enlarged view of part A of FIG. 1 showing the first embodiment. [Figure 3] (a) is a perspective view of a container showing a state where the first primer layer (white gradation) is formed, and (b) is an enlarged view of the container in which a water droplet pattern appears. [Figure 4] It is an enlarged view of part A of FIG. 1 showing the second embodiment.

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a half cross-sectional view of a container provided with a coating structure of a resin molded body according to the present invention, FIG. 2 is an enlarged view of part A of FIG. 1 showing the first embodiment, FIG. 3(a) is a perspective view of a container in which a water droplet pattern appears, and FIG. 3(b) is an enlarged view of FIG. 3(a).

[0020] First, a first embodiment of the coating structure of the resin molded body according to the present invention will be described. The coating structure 10 of the resin molded body 1 according to the present invention is formed on the body portion 2 of a bottle-shaped container 1A made of a synthetic resin as shown in FIG. 1, for example, and has a plurality of layers to form a water droplet pattern P. Such a coating structure 10 of the resin molded body 1 is formed on the surface of the body portion 2 made of a transparent synthetic resin such as PET resin that forms at least the base material layer 2A, and includes a first primer layer 11, a first UV matte layer 12, a printing layer 13, and a UV splash layer 14 that forms the water droplet pattern P, which are laminated from the lower layer to the upper layer, and is based on a four-layer structure.

[0021] As a material for forming the first primer layer 11, for example, a polyester-based primer in which a diluting thinner is mixed with the primer or a heat-dry paint (hereinafter referred to as "first primer paint") manufactured by Toho Kaken Kogyo Co., Ltd., in which a pigment is mixed with this polyester-based primer, is suitable.

[0022] As the material for forming the first UV matte layer 12, a UV paint (hereinafter referred to as "first UV matte paint") is preferred, for example, an acrylic UV matte paint (a colorless, transparent paint that cures ultraviolet light, the same applies hereinafter) manufactured by Toho Kaken Kogyo Co., Ltd., which contains a matting agent for a matte finish (manufactured by Fujikura Kasei Co., Ltd.) and a predetermined pigment (manufactured by Toho Kaken Kogyo Co., Ltd.).

[0023] As the material for forming the UV splash layer 14, a glossy UV paint (hereinafter referred to as "UV splash paint") consisting of an acrylic UV clear (high solids content type) manufactured by Toho Kaken Kogyo Co., Ltd. is preferred.

[0024] The printed layer 13 may be made of any material capable of forming characters, figures, symbols, or combinations thereof, such as ink, metallic foil (vacuum-deposited foil), or pigment foil (coated foil).

[0025] Next, a method for manufacturing the painted structure of the resin molded body shown in the first embodiment described above will be explained. (1) First step (Formation of the first primer layer) A first primer coating having the above configuration is spray-applied onto the surface of a transparent synthetic resin body 2 (base layer 2A), such as PET resin, to form a first primer layer 11, for example, consisting of a white gradient. Subsequently, the surface of the synthetic resin body 2 is dried using a far-infrared dryer (see Figure 3(a)). By forming the first primer layer 11, the adhesion between the base layer 2A and the first UV matte layer 12 is improved, and further, pigments can be added to the primer to provide design features.

[0026] (2) Second step (Formation of UV matte layer) The first UV matte layer 12 is laminated onto the surface of the dried first primer layer 11 by spraying the first UV matte paint having the above configuration. Subsequently, the synthetic resin body 2 is dried using a far-infrared dryer. The first UV matte layer 12, which contains a matting agent, covers the first primer layer 11 and prevents it from being exposed, making it possible to improve scratch resistance and other properties compared to conventional methods.

[0027] (3) Third step (Formation of the printed layer) Next, a printed layer 13 is formed on a portion of the surface of the first UV matte layer 12 by printing predetermined characters, figures, symbols, or combinations thereof onto the surface of the first UV matte layer 12. Examples of printing methods that can be used include silk screen printing, pad printing, and hot stamping.

[0028] (4) Ultraviolet irradiation process (formation of UV splash layer) A UV splash paint consisting of the above configuration is applied to the surface of the first UV matte layer 12, on which a printed layer 13 is formed in part, using a low-pressure spray gun to form a UV splash layer 14. At this time, by reducing the air pressure of the spray gun from 0.2 MPa to 0.05 MPa, a UV splash layer 14 consisting of fine to large particles is formed on the surfaces of the first UV matte layer 12 and the printed layer 13. Subsequently, the body 2 is dried using a far-infrared dryer, and then the body 2 is subjected to ultraviolet irradiation (UV irradiation) to fix the UV splash layer 14.

[0029] This allows a water droplet pattern P, as shown in Figure 3(b), to be applied to the surface of the body 2, i.e., the surface of the first UV matte layer 12 and the printed layer 13. In this case, the UV splash layer 14 and the first UV matte layer 12 containing the previously formed matte agent are irradiated with ultraviolet light (UV irradiation) together, thereby strengthening the adhesion of the UV splash layer 14 to the first UV matte layer 12.

[0030] (Second example) Figure 4 is an enlarged view of part A in Figure 1, showing a second embodiment. In the second embodiment, a second primer layer 15 and a second UV matte layer 16 are laminated between the printed layer 13 and the UV splash layer 14 of the resin molded body coating structure shown in the first embodiment. This ensures reliable protection of the printed layer 13.

[0031] As the material for forming the second primer layer 15, a hot-drying paint (hereinafter referred to as "second primer paint") is preferred, for example, a chlorinated polyolefin-based primer manufactured by Kotobuki Kako Co., Ltd., mixed with a diluted thinner also manufactured by Kotobuki Kako Co., Ltd., and a polyolefin-based primer manufactured by Toho Kaken Kogyo Co., Ltd. Forming the second primer layer 15 can improve the adhesion between the first UV matte layer 12 and the second UV matte layer 16.

[0032] As the material for forming the second UV matte layer 16, for example, an acrylic UV paint (hereinafter referred to as "second UV matte paint") containing a matting agent (manufactured by Fujikura Chemicals Co., Ltd.) in an acrylic UV matte paint manufactured by Toho Chemical Industries, Ltd. is preferred. Previously, the primer layer was exposed, which may have reduced scratch resistance and suitability for the contents. By forming the second UV matte layer 16, scratch resistance and suitability for the contents are improved, a matte finish is achieved, and the gap in gloss between the second UV matte layer 16 and the UV splash layer 14 makes the water droplet pattern P created by the UV splash layer 14 stand out.

[0033] Next, a method for manufacturing the painted structure of the resin molded body shown in the second embodiment described above will be explained. Since some of the manufacturing methods for the resin molded article shown in the second embodiment are the same as the (1) first step, (2) second step, and (3) third step shown in the first embodiment, the steps from the fourth step onward will be described.

[0034] (4) Fourth step (Formation of the second primer layer) The second primer layer 15 is laminated onto the surface of the first UV matte layer 12, which includes the printed layer 13 formed in the third step of the first embodiment, by spraying the second primer coating having the above configuration onto the surface. Subsequently, the second primer layer 15 is dried using a far-infrared dryer.

[0035] (5) Step 5 (Formation of UV matte layer) Next, the second UV matte paint having the above configuration is spray-applied onto the surface of the second primer layer 15 to form the second UV matte layer 16. Subsequently, the second UV matte layer 16 is dried using a far-infrared dryer.

[0036] (6) Ultraviolet irradiation process (formation of UV splash layer) Similar to the first embodiment, a UV splash paint having the above configuration is applied to the surface of the second UV matte layer 16, on which a printed layer 13 is formed in part, using a low-pressure spray gun to form a UV splash layer 14. In this process, the air pressure of the spray gun is reduced from 0.2 MPa to 0.05 MPa, so that a UV splash layer 14 consisting of fine to large particles is formed on the surface of the second UV matte layer 16 and the printed layer 13. Subsequently, the body 2 is dried using a far-infrared dryer, and then UV irradiation is performed to fix the UV splash layer 14.

[0037] This allows a droplet pattern P, as shown in Figure 3(b), to be formed on the surface of the second UV matte layer 16, similar to the first embodiment. In this case, the UV splash layer 14 and the second UV matte layer 16 containing the previously formed matte agent are irradiated with ultraviolet light (UV irradiation) together, which strengthens the adhesion of the UV splash layer 14 to the second UV matte layer 16.

[0038] The configuration of the present invention and its effects have been described above in accordance with the examples, but the embodiments of the present invention are not limited to the above examples. For example, in the above embodiment, a bottle-shaped container 1A was shown and described as an example of a resin molded body 1, but it may also be a cup-shaped container, or something other than a container, such as a case made of synthetic resin.

[0039] Furthermore, although the above embodiment described a case in which the resin molded body 1 is made of a transparent synthetic resin, the resin molded body 1 may also be made of a translucent resin or a colored opaque resin. [Industrial applicability]

[0040] The present invention can be applied to an even wider range of fields related to the coating structure of resin molded articles and the coating method thereof. [Explanation of symbols]

[0041] 1: Resin molded body 1A: Container 2: Torso 2A: Base material layer 10: Painting structure 11: First primer layer 12: First UV matte layer 13: Printing layer 14: UV Splash Layer 15: Second primer layer 16: Second UV matte layer P: Water droplet pattern

Claims

1. A coating structure for a resin molded body, A coating structure for a resin molded body, characterized in that a first primer layer (11) forming at least a base layer, a first UV matte layer (12), a printing layer (13), and a UV splash layer (14) forming a water droplet pattern (P) are sequentially laminated on the surface of the resin molded body (1) from the bottom layer to the top layer.

2. The coating structure for a resin molded article according to claim 1, wherein a second primer layer (15) and a second UV matte layer (16) are laminated between the printed layer (11) and the UV splash layer (14) from the bottom layer to the top layer.

3. A painted resin molded body according to claim 1 or 2, wherein the first primer layer (11) is formed of a polyester primer obtained by mixing a primer with a diluted thinner or a heat-drying paint obtained by mixing a pigment with the polyester primer, the first UV matte layer (12) is formed of a UV paint which contains an acrylic UV matte paint, a matting agent for matting, and a predetermined pigment, the printed layer (13) is formed of letters, figures, or symbols using ink, metallic foil (vacuum-deposited foil), or pigment foil (coated foil), or a combination thereof, and the UV splash layer (14) is formed of a UV paint for glossing which consists of an acrylic UV clear.

4. The coating structure for a resin molded article according to claim 2, wherein the second primer layer (15) is formed of a chlorinated polyolefin-based primer and a hot-drying paint obtained by mixing a diluted thinner and a polyolefin-based primer, and the second UV matte layer (16) is formed of an acrylic UV paint obtained by adding a matting agent to an acrylic UV matte paint.

5. A method for painting the painted structure of a resin molded body, A method for painting a resin molded body, comprising at least the following steps: a first step of spraying a first primer paint onto the surface of the resin molded body (1) and then drying it with far-infrared rays to form a first primer layer (11); a second step of spraying a first UV matte paint onto the surface of the first primer layer (11) and then drying it with far-infrared rays to form a first UV matte layer (12); a third step of forming a printed layer (13) on the surface of the first UV matte layer (12); a fourth step of applying a UV splash paint to form a UV splash layer (14) on the surfaces of the first UV matte layer (12) and the printed layer (3) to create a polka dot pattern (P); and an ultraviolet irradiation step of curing all the UV paints by irradiating them with ultraviolet light.

6. A method for painting a resin molded article according to claim 5, comprising, between the third step and the ultraviolet irradiation step, a fourth step of spraying a second primer paint onto a first UV matte layer (12) which includes a printed layer (13) on a part of its surface, and then drying it with far-infrared rays to form a second primer layer (15); and a fifth step of spraying a second UV matte paint onto the surface of the second primer layer (15), and then drying it with far-infrared rays to form a second UV matte layer (16).

7. The painting method for a resin molded article according to claim 5 or 6, wherein the fourth step is to apply UV splash paint using a low-pressure spray gun.

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