Decorative film for insert molding, method for producing the same, and method for producing resin molded product

Abstract

The present invention provides a decorative film for insert molding, which has high dimensional accuracy related to the gravure-printed pattern layer and the light-transmitting pattern layer and can express a delicate and gray-rich pattern. The multilayer film (20) is provided with a polycarbonate resin layer (22) composed of a polycarbonate resin between a first acrylic resin layer (21) composed of an acrylic resin and a second acrylic resin layer (23), which transmits visible light. The first gravure-printed layer (30) is printed on the first main surface (20a) of the multilayer film (20), and has a first pattern layer (31) that transmits visible light. The backing film (60) is composed of a polycarbonate resin and transmits visible light. The first pattern layer (31) has a first graphic (130) configured at a predetermined position of the three-dimensional shape of the decorative film (10) for insert molding after three-dimensional molding. The light-transmitting pattern layer (71) is patterned so that visible light passes through the first graphic (130) having the light-transmitting pattern (75) configured at a predetermined position of the three-dimensional shape.

Description

Technical Field

[0001] The present invention relates to a decorative film for insert molding, a method for producing the same, and a method for producing a resin molded article. In particular, the present invention relates to a decorative film for insert molding having a gravure-printed decorative pattern for visible light transmission, a method for producing the same, and a method for producing a resin molded article. Background Art

[0002] Conventional decorative films for insert molding include, for example, the one described in Patent Document 1 (Japanese Patent Publication No. 8-5096). The decorative film for insert molding described in Patent Document 1 has a structure in which a first light-transmitting substrate having a decorative pattern printed thereon is disposed, and a pattern layer is sandwiched between the first light-transmitting substrate and a second light-transmitting substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 8-5096 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] Conventional patterns on insert molding decorative films are printed using methods such as screen printing, which lacks grayscale expression and makes it difficult to reproduce beautiful wood grain or gradation. Consequently, patterns on insert molding decorative films often have monotonous designs using textures or solids.

[0008] Furthermore, in conventional insert molding decorative films, it is difficult to overlap different patterns disposed on multiple pattern layers to achieve a comprehensive and aesthetically pleasing design.

[0009] The technical problem of the present invention is to provide a decorative film for insert molding, which has high dimensional accuracy in relation to the gravure-printed pattern layer and the light-transmitting pattern layer and can express a fine pattern with rich grayscales.

[0010] Technical solutions to technical problems

[0011] Hereinafter, a plurality of methods will be described as technical solutions for solving the technical problem, and these methods can be arbitrarily combined as needed.

[0012] A decorative film for insert molding according to one embodiment of the present invention is a film that is three-dimensionally formed before insert molding. The decorative film for insert molding comprises a multilayer film, a first gravure printing layer, a backing film, and a light-transmitting pattern layer. The multilayer film has a first main surface and a second main surface, and a polycarbonate resin layer composed of a polycarbonate resin is arranged between the first acrylic resin layer and the second acrylic resin layer composed of an acrylic resin, and is transparent to visible light. The first gravure printing layer is formed on the first main surface of the multilayer film and has a first pattern layer containing a gravure-printed pattern and is transparent to visible light. The laminating adhesive layer is bonded to the first gravure printing layer and is formed from an adhesive that is transparent to visible light. The backing film is composed of a polycarbonate resin and is bonded to the first gravure printing layer via a laminating adhesive layer and is transparent to visible light. The light-transmitting pattern layer is formed on the backing film and has a light-transmitting pattern that is transparent to visible light. The first pattern layer has a first pattern arranged at a predetermined position. The light-transmitting pattern layer is patterned so that visible light passes through the first pattern arranged at the predetermined position.

[0013] In this insert molding decorative film, the multilayer structure of the multilayer film, including a polycarbonate resin layer, suppresses shrinkage during drying of the printed first gravure-printed layer. Furthermore, the polycarbonate resin layer and the backing film composed of a polycarbonate-based resin in the multilayer film improve heat resistance, suppressing ink flow in the first gravure-printed layer during the manufacture of polycarbonate resin molded articles. As a result, visible light can be guided with high precision from the light-transmitting pattern to the first pattern of the first gravure-printed layer, enabling the placement of the first pattern, which transmits visible light, at a desired location on the resin molded article.

[0014] In addition, in this specification, polycarbonate means that it is produced using a polycarbonate-based resin as a material for injection molding.

[0015] The above-mentioned decorative film for insert molding may also be configured to further include a second gravure-printed layer, formed on the second main surface of the multilayer film, comprising a second pattern layer containing a gravure-printed pattern, the second gravure-printed layer having a second pattern positioned relative to the first pattern. With this structure, the decorative film for insert molding can suppress positional shifting of the first and second patterns during drying.

[0016] The above-mentioned decorative film for insert molding can also be configured such that the maximum height roughness of the surface irregularities of the second gravure-printed layer is 20 μm or greater, and the thickness of the laminating adhesive layer is 16 μm or greater. In such a decorative film for insert molding, the laminating adhesive layer can suppress air trapping caused by the irregularities of the second gravure-printed layer.

[0017] The above-mentioned decorative film for insert molding may be configured such that the first gravure printing layer includes a primer layer made of thermoplastic resin and transparent to visible light between the first pattern layer and the laminating adhesive layer. The decorative film for insert molding configured in this manner protects the first pattern layer through the primer layer.

[0018] One embodiment of the present invention relates to a method for manufacturing a decorative film for insert molding, namely, a film to be three-dimensionally formed before insert molding. In the first step of the insert molding decorative film manufacturing method, a first gravure-printed layer that transmits visible light is printed on the first main surface of a multilayer film having a polycarbonate resin layer disposed between a first acrylic resin layer and a second acrylic resin layer. In the second step, a laminating adhesive layer is provided between a backing film composed of a polycarbonate resin and transmitting visible light and the multilayer film having the first gravure-printed layer formed thereon. The backing film and the multilayer film are dry-laminated at a temperature below 100°C to form a first elongated member. In the fourth step, a light-transmitting pattern layer having a light-transmitting pattern that transmits visible light is formed on the backing film on the first member. In the manufacturing method of the decorative film for insert molding, the first gravure printing layer has a first pattern arranged at a predetermined position of the three-dimensional shape of the decorative film for insert molding after three-dimensional molding, and the light-transmitting pattern layer is patterned so that visible light passes through the first pattern having the light-transmitting pattern arranged at a predetermined position of the three-dimensional shape.

[0019] In the method for manufacturing a decorative film for insert molding, the multilayer structure of the multilayer film, including a polycarbonate resin layer, suppresses shrinkage during drying of the printed gravure-printed layer during the first step. Furthermore, the polycarbonate resin layer and the backing film composed of a polycarbonate-based resin in the multilayer film improve heat resistance, thereby suppressing ink flow in the first gravure-printed layer during the manufacture of a polycarbonate resin molded article. As a result, visible light can be guided with high precision from the light-transmitting pattern to the first pattern of the first gravure-printed layer, enabling the placement of the first pattern, which transmits visible light, at a desired location on the resin molded article.

[0020] The aforementioned method for manufacturing a decorative film for insert molding can also be configured such that, in the first step, a first gravure-printed layer is gravure-printed on the first main surface of the multilayer film, while a second gravure-printed layer is simultaneously printed on the second main surface of the multilayer film. In this method for manufacturing a decorative film for insert molding, the first pattern of the first gravure-printed layer can be precisely positioned relative to the second pattern of the second gravure-printed layer. As a result, visible light can be precisely guided from the light-transmitting pattern to the first pattern of the first gravure-printed layer and the second pattern of the second gravure-printed layer, or around the second pattern. In other words, visible light can be transmitted to a desired location on the resin molded article, allowing the first pattern and the second pattern of the second gravure-printed layer to be precisely positioned relative to the location where the visible light is transmitted.

[0021] The aforementioned method for manufacturing a decorative film for insert molding further includes a third step of cutting the first component to produce a short second component before the fourth step. In the fourth step, a light-transmitting pattern layer is formed on the backing film of the second component. This method for manufacturing a decorative film for insert molding allows for highly precise alignment of the first and second patterns with the light-transmitting pattern using a single second component.

[0022] The above-mentioned method for manufacturing a decorative film for insert molding is configured such that, in the fourth step, a light-transmitting pattern layer is formed on the backing film of the first component by a roll-to-roll method. In the method for manufacturing a decorative film for insert molding configured in this manner, multiple light-transmitting pattern layers can be formed repeatedly and rapidly.

[0023] A method for manufacturing a resin molded article according to one embodiment of the present invention comprises a molding step for three-dimensionally molding the insert molding decorative film, a trimming step, and an injection molding step. In the trimming step, unnecessary portions of the insert molding decorative film, which has been given a three-dimensional shape in the molding step, are trimmed and removed. The resin molded article obtained by this method is configured such that a first pattern is arranged at a specific location within the three-dimensional product shape of the resin molded article, and visible light transmitted through the light-transmitting pattern passes through the first pattern or the area surrounding the first pattern. In this method for manufacturing a resin molded article, the polycarbonate resin layer of the multilayer film and the backing film composed of a polycarbonate-based resin enhance heat resistance, thereby suppressing ink flow in the first gravure printing layer during the injection molding step. As a result, visible light can be guided from the light-transmitting pattern to the first pattern of the first gravure printing layer or the area surrounding the first pattern with high precision. In other words, visible light passes through a desired portion of the resin molded article, and the first pattern can be precisely positioned relative to the position of the transmitted visible light.

[0024] Effects of the Invention

[0025] The insert molding decorative film of the present invention can produce a polycarbonate resin molded article that has high dimensional accuracy for the gravure-printed pattern layer and the light-transmitting pattern layer, and can express a fine, richly gradated pattern. Furthermore, the method for producing the insert molding decorative film of the present invention is suitable for producing the insert molding decorative film of the present invention. Furthermore, the method for producing a resin molded article of the present invention is suitable for producing a polycarbonate resin molded article using the insert molding decorative film of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A It is a perspective view showing a display panel to which the decorative film for insert molding according to the embodiment is applied.

[0027] Figure 1B This is a perspective view of a display panel showing a state in which visible light is transmitted around letters and icons.

[0028] Figure 2 This is a schematic cross-sectional view showing a state where the decorative film for insert molding is heated for molding.

[0029] Figure 3 It is a schematic cross-sectional view showing a state where the decorative film for insert molding is three-dimensionally molded.

[0030] Figure 4 It is a schematic cross-sectional view showing a state where the decorative film for insert molding is trimmed.

[0031] Figure 5 It is a schematic cross-sectional view showing a state where the decorative film for insert molding is set in a mold.

[0032] Figure 6 This is a schematic cross-sectional view showing a state where molten resin is injected into a mold provided with a decorative film for insert molding.

[0033] Figure 7 It is a schematic cross-sectional view showing a state where the resin molded product integrated with the insert molding decorative film is taken out from the mold.

[0034] Figure 8A This is a schematic cross-sectional view showing an example of the structure of a decorative film for insert molding.

[0035] Figure 8B This is a schematic exploded perspective view showing a portion of the layers of the display panel in an enlarged manner in order to explain the arrangement of the first pattern of the first pattern layer, the second pattern of the second pattern layer, and the light-transmitting pattern in the display panel.

[0036] Figure 9 This is a schematic cross-sectional view showing an example of the structure of a multilayer film on which a gravure-printed layer is printed.

[0037] Figure 10It is a schematic cross-sectional view for explaining the step of dry laminating the multilayer film and the liner film.

[0038] Figure 11 This is a schematic diagram showing the steps of cutting a component of the decorative film for insert molding.

[0039] Figure 12 This is a schematic cross-sectional view showing another example of the structure of a multilayer film on which a gravure-printed layer is printed.

[0040] Figure 13 This is a schematic cross-sectional view showing another example of the structure of a multilayer film on which a gravure-printed layer is printed. DETAILED DESCRIPTION

[0041] (1) Application of decorative films for insert molding

[0042] Figure 1A as well as Figure 1B An example of a display panel 1 mounted on a center console 900 of an automobile is shown. Display panel 1 is a portion of center console 900 and is a polycarbonate resin molded product. Display panel 1 has a three-dimensional shape that matches the shape of center console 900. A shift lever 910 is disposed on center console 900. Shift lever 910 is the operating lever of an automatic transmission (not shown). For example, an opening (not shown) for accommodating shift lever 910 is formed in display panel 1.

[0043] The display panel 1 is decorated with an insert molding decorative film 10. The insert molding decorative film 10 is three-dimensionally formed to match the shape of the resin molded product (here, the display panel 1) before insert molding. The insert molding decorative film 10 includes a first pattern 130, a second pattern 140, and a light-transmitting pattern 75 for decorative purposes.

[0044] As the first graphic 130, in this embodiment, a wood grain pattern consisting of dark brown parts and light brown parts is shown as an example. The wood grain pattern can also be called an annual ring pattern. The dark brown part of the wood grain pattern represents the dense tissue of trees grown in winter, and the light brown part of the wood grain pattern represents the coarse tissue of trees grown in summer. Figure 2 In FIG, a dark brown portion of the wood grain pattern is schematically shown by a curve 131 .

[0045] As the second graphic 140, in this embodiment, the surface concave and convex of a wood grain-like pattern is shown as an example. The dark brown portion of the wood grain-like pattern represented by curve 131 has a dense structure and is therefore harder than the light brown portion, and tends to protrude more easily than the light brown portion when processing wood. Panels processed from wood sometimes have a relief pattern in which the dark brown portion emerges. In order to manufacture a resin molded product similar to a panel processed from such wood, a convex pattern is overlapped on the curve 131. In addition, a concave pattern is overlapped on the light brown portion between adjacent curves 131. The second graphic is a wood grain-like concave and convex pattern 141 formed by combining the above-mentioned convex and concave patterns.

[0046] The light-transmitting pattern 75 includes, for example, a display portion containing letters 75a indicating the various operating positions (ranges) of the shift lever 910, and icons 75b for operating devices within the vehicle. The letters 75a are surrounded by a rectangular frame. The light-transmitting pattern 75 includes, for example, a rectangular display portion for displaying the letters 75a. Furthermore, the icons 75b are surrounded by an oval frame. The light-transmitting pattern layer 71 includes, for example, a display portion 75c for a digital clock, and a rectangular pattern 75d that transmits visible light emitted from the liquid crystal screen 920.

[0047] The display panel 1 includes a flat portion 2 on which characters 75a, icons 75b, and a wood-grain-like concave-convex pattern 141 are formed, and a skirt portion 3 surrounding the flat portion 2. The skirt portion 3 is a portion that is bent toward the vehicle body relative to the flat portion 2. As the boundary with the skirt portion 3, the flat portion 2 has a first end 2a and a third end 2c in the direction of travel of the vehicle (hereinafter sometimes referred to as the X-axis direction), and a second end 2b and a fourth end 2d in the direction in which the driver's seat and the passenger seat are arranged (hereinafter sometimes referred to as the Y-axis direction).

[0048] The first end 2 a , the second end 2 b , the third end 2 c , and the fourth end 2 d of the flat portion 2 are the outer edges of the wood-grain concave-convex pattern 141 , and can be regarded as the outer edges of the second graphic 140 .

[0049] (2) Method for manufacturing resin molded products using decorative films for insert molding

[0050] Figures 2 to 7 The following summarizes a method for manufacturing a resin molded article using an insert molding decorative film 10. The insert molding decorative film 10 is a film used for three-dimensional molding prior to insert molding. For example, when decorating a display panel 1, the insert molding decorative film 10 is molded to match the three-dimensional shape of the display panel 1 and then inserted into a mold during injection molding of the display panel 1.

[0051] like Figure 2 and Figure 3As shown in FIG, the molding process is a process of three-dimensionally molding the decorative film 10 for insert molding. Figure 2 As shown, the insert molding decorative film 10 is placed on the mold 200. The insert molding decorative film 10 is heated by the heat source 210 and softened. Figure 2 The arrows in FIG. 1 represent the amount of heat applied to the insert molding decorative film 10. Figure 3 As shown, the insert molding decorative film 10 is formed into a product shape according to a mold 200 by, for example, vacuum forming or pressure forming. Figure 3 The arrows shown in FIG. 3 indicate the directions of forces applied to the insert molding decorative film 10 by vacuum molding or pressure molding.

[0052] like Figure 4 As shown, the trimming step is a step of trimming and removing unnecessary portions of the insert molding decorative film 10 that has been given a three-dimensional shape in the molding step. For trimming, a die cutter or a laser is used, for example. Figure 4 A die 220 of a die cutter is shown, and trimming using the die cutter is shown.

[0053] An example of an injection molding process Figures 5 to 7 The injection molding process is a process in which the insert molding decorative film 10 is placed in a mold 230 and a polycarbonate-based resin is injected into the mold 230, thereby molding a display panel 1, a resin molded product made of polycarbonate and decorated with the insert molding decorative film 10. While the display panel 1 is described here as an example of a resin molded product, the resin molded product is not limited to the display panel 1. Figure 5 The state in which the three-dimensionally formed insert molding decorative film 10 is set on the mold 230 after the mold is opened is shown. Figure 5 The insert molding decorative film 10 is shown to be placed on a mold 230 by a robot arm 240 . Figure 5 The arrow indicates the moving direction of the insert molding decorative film 10 .

[0054] Figure 6 The figure shows a state where molten resin 290, which is a heated and melted polycarbonate resin, is injected into the cavity 235 of the mold 230 after the mold is closed. The typical molding temperature (temperature of the molten resin 290) for the display panel 1 primarily made of polycarbonate resin is 260°C to 320°C. The insert molding decorative film 10 of the first embodiment can be molded at a molding temperature of 300°C or higher. Figure 6 The arrow in represents the movement of the movable mold in the mold 230 during mold closing. Figure 7 The figure shows the state where mold 230 is opened and display panel 1 is removed. Display panel 1 is a resin molded product made of polycarbonate resin. When mold 230 is opened, robot arm 240 enters and removes display panel 1, a resin molded product, from mold 230. Figure 7 The arrows shown on the mold 230 indicate the moving direction of the movable mold. The arrows shown around the robot arm 240 and the display panel 1 indicate the moving direction of the display panel 1 (resin molded product).

[0055] (3) Structure of the Decorative Film 10 for Insert Molding

[0056] like Figure 8A As shown, the decorative film 10 for insert molding includes a multilayer film 20 , a first gravure printing layer 30 , a second gravure printing layer 40 , an adhesive layer 50 for lamination, a cushion film 60 , and a screen printing layer 70 .

[0057] (3-1) Multilayer film 20

[0058] The multilayer film 20 has a first principal surface 20a and a second principal surface 20b. The thickness of the multilayer film 20 is, for example, 30 μm to 150 μm. A multilayer film 20 having a thickness of 30 μm to 150 μm is suitable for gravure printing. In this first embodiment, the thickness of the multilayer film 20 is, for example, 50 μm. The multilayer film 20 comprises a polycarbonate resin layer 22 disposed between a first acrylic resin layer 21 and a second acrylic resin layer 23. The exposed surface of the first acrylic resin layer 21 is the first principal surface 20a, and the exposed surface of the second acrylic resin layer 23 is the second principal surface 20b.

[0059] The first acrylic resin layer 21 and the second acrylic resin layer 23 are made of an acrylic resin. An example of an acrylic resin used in the first acrylic resin layer 21 and the second acrylic resin layer 23 is PMMA. In the present invention, the first acrylic resin layer 21 and the second acrylic resin layer 23 being made of an acrylic resin includes not only the case where these layers are made solely of an acrylic resin but also the case where an additive is added to the acrylic resin.

[0060] The polycarbonate resin layer 22 is composed of a polycarbonate resin. As the polycarbonate resin used in the polycarbonate resin layer 22, for example, there is a polycarbonate resin. In the present invention, when the polycarbonate resin layer 22 is composed of a polycarbonate resin, it includes not only the case where the layer is composed only of a polycarbonate resin, but also the case where additives are added to the polycarbonate resin. In order to suppress the shrinkage rate during gravure printing, the thickness of the polycarbonate resin layer 22 must be less than the thickness of the multilayer film 20, but is preferably 10μm to 105μm. In addition, the glass transition temperature (Tg) of the polycarbonate resin layer 22 is, for example, 120℃ to 200℃. In order to obtain high heat resistance, the glass transition temperature (Tg) of the polycarbonate resin layer 22 is preferably high, preferably 150℃ to 200℃, and more preferably 170℃ to 200℃. It should be noted that the glass transition temperature (Tg) is measured in accordance with JIS7121.

[0061] For the multilayer film 20, the shrinkage rate during gravure printing is preferably suppressed within the range of -0.20% to +0.20% in both the conveyance direction and the width direction of the multilayer film 20, and more preferably suppressed within the range of -0.15% to +0.15%.

[0062] (3-2) First gravure printing layer 30

[0063] The first gravure printing layer 30 is formed on the first main surface 20a of the multilayer film 20. More specifically, the first gravure printing layer 30 is formed by printing on the first main surface 20a of the multilayer film 20 (the exposed surface of the first acrylic resin layer 21). The first gravure printing layer 30 includes a first pattern layer 31 and a primer layer 32. The first pattern layer 31 is formed using an existing gravure ink. The gravure ink contains a binder resin, a solvent, and a colorant. Examples of the binder resin include vinyl chloride vinyl acetate copolymer resins, acrylic resins, polyester resins, and polyurethane resins. The solvent is used to dissolve the resin and can be selected based on the resin. Examples of solvents for gravure printing ink include toluene, methyl ethyl ketone, ethyl acetate, and isopropyl alcohol.

[0064] On the first pattern layer 31, for example Figure 1A as well as Figure 1B In the embodiment, a first graphic 130 having a wood grain pattern represented by a curve 131 is formed.

[0065] The primer layer 32 is a layer for coating the laminating adhesive layer 50. The primer layer 32 transmits visible light. Materials such as vinyl chloride-vinyl acetate copolymer resins, acrylic resins, polyester resins, and polyurethane resins are used to form the primer layer 32. The primer layer 32 protects the first pattern layer 31.

[0066] (3-3) Second Gravure Printing Layer 40

[0067] The second gravure-printed layer 40 is formed on the second main surface 20b of the multilayer film 20. More specifically, the second gravure-printed layer 40 is formed by printing on the second main surface 20b (the exposed surface of the second acrylic resin layer 23) of the multilayer film 20. The second gravure-printed layer 40 includes a second pattern layer 41. Like the first pattern layer 31, the second pattern layer 41 is formed using conventional gravure ink. Since the gravure ink used to form the first pattern layer 31 has already been described, the description of the gravure ink used for the second gravure-printed layer 40 will be omitted.

[0068] The second gravure-printed layer 40 is a matte layer. The maximum height roughness (Rz) of the surface irregularities of this matte layer (measured according to JIS B0601) is less than 20 μm, primarily creating a visual impression of the irregularities. In contrast, when producing a product with tactile specifications, the maximum height roughness (Rz) of the surface irregularities of the matte layer (measured according to JIS B0601) is 20 μm or greater, primarily creating a visual impression of the irregularities as well as a tactile impression of the irregularities. The second gravure-printed layer 40 can be a matte layer that creates a visual impression of the irregularities or a matte layer that creates a tactile impression of the irregularities.

[0069] (3-4) Lamination Adhesive Layer 50

[0070] The laminating adhesive layer 50 bonds the first gravure-printed layer 30 and the backing film 60. Therefore, the laminating adhesive layer 50 is disposed between the first gravure-printed layer 30 and the backing film 60. The adhesive constituting the laminating adhesive layer 50 may be, for example, a two-component curable urethane resin, a two-component curable polyester-urethane resin, or a two-component curable ester resin. These adhesives constituting the laminating adhesive layer 50 are suitable for dry lamination at low temperatures of 100°C or less.

[0071] When the maximum height roughness of the concavo-convex surface of the second gravure printing layer 40 (Rz: roughness measured in accordance with JIS B0601) is 20 μm or greater, the thickness of the laminating adhesive layer 50 is preferably 16 μm or greater. By setting the thickness of the laminating adhesive layer 50 as described above, it is possible to suppress the occurrence of air accumulation after dry lamination. In addition, to prevent the occurrence of air accumulation, when the maximum height roughness of the concavo-convex surface of the second gravure printing layer 40 is 20 μm or greater, the thickness of the laminating adhesive layer 50 is preferably 20 μm or greater, and more preferably 25 μm or greater. It should be noted that even when the maximum height roughness of the concavo-convex surface of the second gravure printing layer 40 is 20 μm or greater, the thickness of the laminating adhesive layer 50 is preferably 30 μm or less. This is because if the thickness of the laminating adhesive layer 50 is thicker than 30 μm, there is a risk of foaming or reduced surface hardness during the molding process.

[0072] In other words, to suppress air trapping, the thickness of the laminating adhesive layer 50 is preferably at least 80% of the maximum height roughness of the concavo-convex surface of the second gravure-printed layer 40. To prevent air trapping, the thickness of the laminating adhesive layer 50 is preferably at least the maximum height roughness of the concavo-convex surface of the second gravure-printed layer 40, more preferably 1.25 times the maximum height roughness. Regardless of the maximum height roughness of the concavo-convex surface of the second gravure-printed layer 40, the thickness of the laminating adhesive layer 50 is set to at least 3 μm.

[0073] It should be noted that the second main surface 20b of the multilayer film 20 may have portions where the second gravure-printed layer 40 is formed and portions where the second gravure-printed layer 40 is not formed. In such cases, the step from the second main surface 20b of the multilayer film 20 to the surface of the second gravure-printed layer 40 is considered as the unevenness of the second gravure-printed layer 40.

[0074] (3-5) Cushion Film 60 and Screen Printing Layer 70

[0075] The backing film 60 is made of a polycarbonate resin that transmits visible light and has a thickness of, for example, 150 μm to 250 μm.

[0076] The screen-printed layer 70 is formed on the backing film 60 by screen printing. The screen-printed layer 70 includes a light-transmitting pattern layer 71 and an adhesive layer 72 for insert molding. The light-transmitting pattern layer 71 is screen-printed to form a shielding portion 71b that blocks visible light. The portion not printed with the shielding portion 71b becomes a light-transmitting portion 71a. It should be noted that the light-transmitting portion 71a may also include a translucent area, for example, to display a color icon 75b. For example, to display a blue icon 75b, a translucent area that transmits blue visible light may be provided in the light-transmitting portion 71a.

[0077] The light-transmitting pattern 75 of the light-transmitting pattern layer 71 is aligned with the first pattern 130 during printing. By such alignment, the visible light passing through the light-transmitting pattern of the light-transmitting pattern layer 71 can pass through the predetermined portions of the first pattern layer 31 and the second pattern layer 41. Figure 1B As shown, first pattern 130 that transmits visible light, or first pattern 130 that transmits visible light around it, is positioned at a predetermined position on display panel 1 (resin molded article) to be decorated, and therefore requires high dimensional accuracy. Similarly, second pattern 140 that transmits visible light, or second pattern 140 that transmits visible light around it, is positioned relative to first pattern 130, and therefore requires high dimensional accuracy.

[0078] exist Figure 8B 1 shows a portion of a curve 131 as an example of a first graphic 130 and a portion of a wood grain-like concave-convex pattern 141 as an example of a second graphic 140. The curve 131 is formed on the first pattern layer 31, and the wood grain-like concave-convex pattern 141 is formed on the second pattern layer 41. By aligning the first pattern layer 31 with the second pattern layer 41, the curve 131 and the concave-convex pattern 141 are aligned. Figure 8B In FIG. 1 , the dark brown portion is shown as a curve 131 having a width. When the optimal alignment is performed, the ridge line 141r (at the Figure 8BThe line (indicated by a single-dot chain line in FIG) coincides with the line passing through the center of the curve 131 when viewed from above. Here, viewed from above means viewed from the direction in which visible light is transmitted.

[0079] For example, as an example of producing defective products, the projection line 141pr of the ridge line 141r projected onto the first pattern layer 31 may be offset to Figure 8B The offset direction of the projection line 141pr is Figure 8B The tangent direction of the curve 131 shown in FIG. In addition, the distance between the center line of the curve 131 and the projection line 141pr is shown as the distance X1. Figure 8B If the distance X1 becomes larger, for example, a sense of difference will occur between the pattern obtained by the user touching the display panel 1 with his hand and the pattern captured by the user with his vision. The greater the sense of difference, the lower the commodity value of the display panel 1. The distance X1 is preferably suppressed to less than ±0.5mm. Here, it is explained Figure 8B The deviation in the tangential direction of the curve 131 shown in FIG. 1 is preferably suppressed to ±0.5 mm or less, but the deviation in the direction perpendicular to the tangential direction is also preferably suppressed to ±0.5 mm or less. It should be noted that the direction for suppressing the deviation can be set appropriately and is not limited to the above-mentioned direction.

[0080] Furthermore, the letters 75a, icons 75b, display portion 75c, and rectangular pattern 75d are arranged at predetermined positions, for example, with reference to the flat portion 2 of the display panel 1. Therefore, the letters 75a, icons 75b, display portion 75c, and rectangular pattern 75d are aligned with the first pattern layer 31 or the second pattern layer 41. For example, if the display portion 75c is printed offset so as to be tilted relative to the second end portion 2b of the flat portion 2 of the display panel 1, the display panel 1 may become defective.

[0081] (4) Method for manufacturing the decorative film 10 for insert molding

[0082] Figures 9 to 11 An example of a method for producing the insert molding decorative film 10 is shown. Figure 9 as well as Figure 10 Indicates the cross section of a portion of a long sheet. First, as Figure 9 As shown, in the first step, a first gravure-printed layer 30 and a second gravure-printed layer 40 are formed by gravure printing on the first main surface 20a and the second main surface 20b of the multilayer film 20. First, the first pattern layer 31 and the second pattern layer 41 are simultaneously printed on the multilayer film 20 by gravure printing. By printing simultaneously, it is possible to reduce the offset caused by printing the first pattern layer 31 and the second pattern layer 41. Next, a primer layer 32 is printed on the first pattern layer 31 by gravure printing.

[0083] In the first step, after printing the first gravure printing layer 30 and the second gravure printing layer 40, a heat treatment is performed at a temperature higher than the evaporation temperature of the solvent in the gravure ink used to form the first gravure printing layer 30 and the second gravure printing layer 40. This heat treatment reduces the residual solvent in the gravure ink compared to before the heat treatment.

[0084] The second step includes a step of forming the adhesive layer 50 for lamination and a step of laminating. Figure 9 An adhesive that transmits visible light is applied to the gravure-printed multilayer film 20 by a roll-to-roll process to form a laminating adhesive layer 50. Here, the laminating adhesive layer 50 is formed on the gravure-printed multilayer film 20 as an example, but the laminating adhesive layer 50 can also be formed on a liner film 60.

[0085] Next, the gravure-printed multilayer film 20 and the liner film 60 are laminated at a low temperature of 100° C. or lower by dry lamination using a roll-to-roll method with the adhesive layer 50 for lamination.

[0086] like Figure 11 As shown in FIG. 5 , the first component 11 after dry lamination is in a state like a roller 500. In the next step, as shown in FIG. Figure 11 As shown, a single sheet 510 of the first component 11 is produced from the roller 500 of the first component 11. The single sheet 510 is a short second component. The single sheet 510 is produced using, for example, a slit process or a cutting process. In other words, the long first component 11 pulled from the roller 500 is cut into short single sheets 510 (second components) of a predetermined length. The process of producing the short second component, namely the single sheet 510, from the long first component 11 is the third step.

[0087] In the fourth step of screen printing, a screen printing layer 70 is formed on the backing film 60 of the first component 11 of the single sheet. A light-transmitting pattern layer 71 is printed on the backing film 60 by screen printing using ink used for conventional screen printing. The light-transmitting pattern layer 71 is formed into a shielding portion 71b that blocks visible light by screen printing, and the portion where the shielding portion 71b is not printed is used as a light-transmitting portion 71a. When printing the light-transmitting pattern layer 71, the light-transmitting pattern 75 of the light-transmitting pattern layer 71 is aligned with the first pattern 130 of the first pattern layer 31 and the second pattern 140 of the second pattern layer 41. Thus, as shown in FIG. Figure 8AAs shown, visible light Li transmitted through the light-transmitting pattern 75 transmits the first pattern 130 of the first pattern layer 31 located at a predetermined position. Furthermore, visible light Li transmitted through the light-transmitting pattern 75 transmits the second pattern 140 of the second pattern layer 41, which is arranged with reference to the first pattern 130. By using a single sheet 510 to align the light-transmitting pattern 75 of the light-transmitting pattern layer 71 with the first pattern 130 of the first pattern layer 31 and the second pattern 140 of the second pattern layer 41, the positions of the light-transmitting pattern 75, the first pattern 130, and the second pattern 140 can be aligned with high precision.

[0088] Furthermore, an insert molding adhesive layer 72 is screen-printed on the light-transmitting pattern layer 71. Materials for forming the insert molding adhesive layer 72 include, for example, vinyl chloride-vinyl acetate copolymer resin, polyester resin, acrylic resin, urethane resin, and polycarbonate resin.

[0089] (5) Modification

[0090] (5-1) Modification A

[0091] In the above embodiment, the second gravure-printed layer 40 is formed on the surface (second main surface 20b) of the multilayer film 20 during the manufacture of the display panel 1. However, the multilayer film 20 without the second gravure-printed layer 40 may also be used to manufacture the display panel 1 as a resin molded article.

[0092] (5-2) Modification B

[0093] In the above embodiment, the first pattern layer 31 and the second pattern layer 41 are formed on the first gravure printing layer 30 and the second gravure printing layer 40. However, if Figure 12 As shown in FIG. 8 , a light-transmitting pattern layer 81 may be provided as the second gravure printing layer 80. In this case, the laminating adhesive layer 50 and the primer layer 82 are disposed between the light-transmitting pattern layer 81 and the liner film 60. Figure 12 In the example of the insert molding decorative film 10 shown, the light-transmitting pattern layer 81 and the primer layer 82 are formed by gravure printing. The light-transmitting pattern layer 81 can be formed of the same material as the first pattern layer 31, and the primer layer 82 can be formed of the same material as the primer layer 32.

[0094] On the light-transmitting pattern layer 81 of the second gravure printing layer 80, a Figure 8B The light-transmitting pattern 85 of the oval icon 75b shown in FIG. In this example, light-transmitting pattern 85 is formed by gravure printing to form a shielding portion 81b that blocks visible light. The portion where shielding portion 81b is not printed and the printed translucent portion serve as light-transmitting portion 81a. Shielding portion 81b has the same function as shielding portion 71b, and light-transmitting portion 81a has the same function as light-transmitting portion 71a.

[0095] (5-3) Modification C

[0096] In the above embodiment, an example is described in which the third step is performed before the fourth step, in which a short second member, namely a single sheet 510, is produced from a long first member 11. However, a roll-to-roll method can also be used to form the light-transmitting pattern layer 71 on the backing film 60 of the first member 11 using the long first member 11. The light-transmitting pattern layer 71 can be formed on the backing film 60 by screen printing. The roll-to-roll method allows the long first member 11 to be used directly, allowing the light-transmitting pattern layer 71 to be formed quickly.

[0097] (5-4) Modification D

[0098] like Figure 13 As shown, the second gravure printing layer 40 may also be a printing layer other than the matte layer.

[0099] Figure 13 The illustrated insert molding decorative film 10 has two first pattern layers 31a and 31b formed on a first gravure-printed layer 30. The first pattern layer 31a is printed with a pattern that primarily appears when visible light Li is not transmitted. The first pattern layer 31b is positioned farther from the multilayer film 20 than the first pattern layer 31a. Therefore, when the insert molding decorative film 10 is viewed from the second gravure-printed layer 40 when not irradiated with visible light Li, the pattern printed on the first pattern layer 31a is primarily visible. For example, an icon 75b is printed on the first pattern layer 31b, which is positioned behind the first pattern layer 31a having a wood-grain pattern. When irradiated with visible light Li, the icon 75b appears to float. Figure 13 The positional deviation between the pattern of the first pattern layer 31 a and the pattern of the second pattern layer 41 and the positional deviation between the pattern of the first pattern layer 31 b and the pattern of the second pattern layer 41 are preferably suppressed to ±0.5 mm or less.

[0100] (6) Characteristics

[0101] (6-1)

[0102] In the above-mentioned decorative film for insert molding 10, the multilayer film 20 includes a polycarbonate resin layer 22 made of a polycarbonate resin, disposed between a first acrylic resin layer 21 and a second acrylic resin layer 23, each made of an acrylic resin, to transmit visible light. The multilayer structure of the multilayer film 20, including this polycarbonate resin layer 22, can suppress shrinkage during drying of the printed material when forming the first gravure-printed layer 30. Furthermore, the polycarbonate resin layer 22 of the multilayer film 20 and the backing film 60 made of a polycarbonate resin enhance heat resistance, thereby suppressing ink flow in the first gravure-printed layer 30 during the manufacture of a polycarbonate display panel 1 (an example of a resin molded article). As a result, visible light can be guided with high precision from the light-transmitting pattern 75 to the first graphic 130 of the first gravure-printed layer 30. This allows the first graphic 130, which transmits visible light, to be precisely positioned at a desired location on the display panel 1.

[0103] It should be noted that ink flow refers to a phenomenon in which the resin used for printing melts due to high temperature.

[0104] (6-2)

[0105] Furthermore, the multilayer structure of the multilayer film 20 including the polycarbonate resin layer 22 as described above can suppress shrinkage during drying of the printed material not only when forming the first gravure-printed layer 30, but also when forming the second gravure-printed layers 40 and 80. Furthermore, the polycarbonate resin layer 22 of the multilayer film 20 and the liner film 60 composed of a polycarbonate-based resin improve heat resistance, and when manufacturing a display panel 1 made of polycarbonate, it is possible to suppress the occurrence of ink flow not only in the first gravure-printed layer 30, but also in the second gravure-printed layers 40 and 80.

[0106] In particular, when the first gravure-printed layer 30 and the second gravure-printed layers 40 and 80 are simultaneously formed by gravure printing, it is possible to further reduce the misalignment between the first and second patterns 130 and 140, or between the first pattern 130 and the light-transmitting pattern 85. The position of the first pattern 130 of the first gravure-printed layer 30 can be precisely aligned with the positions of the second pattern 140 of the second gravure-printed layers 40 and 80 and the light-transmitting pattern 85. As a result, the second pattern 140 of the second gravure-printed layer 40 can be precisely positioned relative to the first pattern 130, or the first pattern 130 can be positioned at a desired location on the display panel 1 (an example of a resin molded article) so that visible light Li can pass through that location with high precision.

[0107] (6-3)

[0108] In the above-described insert molding decorative film 10, the maximum height roughness of the surface irregularities of the second gravure printed layer 40 is preferably 20 μm or greater, and the thickness of the laminating adhesive layer 50 is preferably 16 μm or greater. In the insert molding decorative film 10 thus configured, the laminating adhesive layer 50 can suppress air trapping caused by the irregularities of the second gravure printed layer 40.

[0109] (6-4)

[0110] The insert molding decorative film 10 is preferably configured such that the first gravure printing layer 30 includes a thermoplastic resin primer layer 32 that transmits visible light between the first pattern layer 31 and the laminating adhesive layer 50. The insert molding decorative film 10 thus configured protects the first pattern layer 31 with the primer layer 32.

[0111] While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications can be made without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be arbitrarily combined as needed.

[0112] Description of Reference Numerals

[0113] 1: Display panel (example of a resin molded product); 10: Decorative film for insert molding; 20: Multilayer film; 21: First acrylic resin layer; 22: Polycarbonate layer; 23: Second acrylic resin layer; 30: First gravure printing layer; 31: First pattern layer; 32: Primer layer; 40, 80: Second gravure printing layer; 41: Second pattern layer; 50: Adhesive layer for lamination; 60: Backing film; 70: Screen printing layer; 71, 81: Light-transmitting pattern layer; 75, 85: Light-transmitting pattern; 130: First graphic; 140: Second graphic.

Claims

1. A decorative film for insert molding, It is a three-dimensional film formed before insert molding, with: A multilayer film having a first main surface and a second main surface, wherein a polycarbonate resin layer composed of a polycarbonate resin is disposed between a first acrylic resin layer composed of an acrylic resin and a second acrylic resin layer, and transmits visible light; a first gravure printing layer formed on the first main surface of the multilayer film, comprising a first pattern layer including a gravure-printed pattern, and transmitting visible light; a laminating adhesive layer, bonded to the first gravure printing layer, and composed of an adhesive that transmits visible light; a liner film made of a polycarbonate resin, adhered to the first gravure printing layer via the laminating adhesive layer, and transparent to visible light; as well as a light-transmitting pattern layer formed on the liner film and having a light-transmitting pattern that transmits visible light, The first pattern layer has a first pattern arranged at a predetermined position. The light-transmitting pattern layer is patterned so that visible light passes through the first pattern, and the light-transmitting pattern is arranged at the predetermined position of the first pattern. further comprising a second gravure printing layer, the second gravure printing layer being formed on the second main surface of the multilayer film and comprising a second pattern layer including a gravure-printed pattern, The second gravure printing layer has a second pattern arranged at a position based on the first pattern. The maximum height roughness of the surface irregularities of the second gravure printing layer measured in accordance with JIS B0601 is 20 μm or more. The laminating adhesive layer has a thickness of 16 μm or more.

2. The decorative film for insert molding according to claim 1, wherein The first gravure printing layer includes a primer layer made of a thermoplastic resin and transmitting visible light between the first pattern layer and the laminating adhesive layer.

3. A method for manufacturing a decorative film for insert molding, wherein the decorative film for insert molding is a film that is three-dimensionally formed before insert molding, the manufacturing method comprising: In a first step, a first gravure-printed layer that transmits visible light is printed on a first main surface of a multilayer film by gravure printing, wherein the multilayer film is a film that transmits visible light and includes a polycarbonate resin layer disposed between a first acrylic resin layer and a second acrylic resin layer. In a second step, a laminating adhesive layer is provided between a liner film made of a polycarbonate resin and transparent to visible light and the multilayer film having the first gravure printed layer formed thereon, and the liner film and the multilayer film are dry-laminated at a temperature of 100° C. or less to form a long first member. as well as In the fourth step, a light-transmitting pattern layer having a light-transmitting pattern that transmits visible light is formed on the liner film on the first component. The first gravure printing layer has a first pattern arranged at a predetermined position of the three-dimensional shape of the insert molding decorative film after three-dimensional molding. The light-transmitting pattern layer is patterned so that visible light passes through the first pattern, and the light-transmitting pattern is arranged at the predetermined position of the three-dimensional shape in the first pattern. In the first step, the first gravure printing layer is printed on the first main surface of the multilayer film by gravure printing, and the second gravure printing layer is printed on the second main surface of the multilayer film at the same time. The maximum height roughness of the surface irregularities of the second gravure printing layer measured in accordance with JIS B0601 is 20 μm or more. The laminating adhesive layer has a thickness of 16 μm or more.

4. The method for manufacturing a decorative film for insert molding according to claim 3, wherein: Before the fourth step, there is also a third step of cutting the first component to produce a short second component. In the fourth step, the light-transmitting pattern layer is formed on the liner film of the second member.

5. The method for manufacturing a decorative film for insert molding according to claim 3, wherein: In the fourth step, the light-transmitting pattern layer is formed on the backing film of the first component by a roll-to-roll method.

6. A method for manufacturing a resin molded article, comprising: a molding step of three-dimensionally molding the decorative film for insert molding according to claim 1 or 2; a trimming step of trimming and removing unnecessary portions of the insert molding decorative film that has been given a three-dimensional shape in the molding step; as well as In the injection molding step, the insert molding decorative film is placed in a mold, and a polycarbonate resin is injected into the mold to form a polycarbonate resin molded article that is decorated with the insert molding decorative film and transmits visible light. The resin molded product is configured such that the first pattern is arranged at a specific location in a three-dimensional product shape of the resin molded product, and visible light transmitted through the light-transmitting pattern transmits the first pattern or a periphery of the first pattern.

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