JP2024056311A - Manufacturing method of double-sided in-mold molded product, and double-sided in-mold molded product - Google Patents

Abstract

[Problem] To provide a method for manufacturing a double-sided in-mold molded product that is inexpensive and has a good appearance. [Solution] A first transfer film 30a having a through hole 31 is laid across a first mold member 20a with the area including the through hole being adhered to the inner surface of the first mold member, a second transfer film 30b is laid across a second mold member 20b, and the mold 20 is closed to sandwich the first and second transfer films in a state where they face each other in a cavity 23, whereupon an inflow path for molten resin 40 is formed that communicates with the cavity from a gate 21 via the through hole while the through hole is disposed within the cavity, and the molten resin is injected through the through hole into the area where the first and second transfer films face each other while filling the cavity, thereby forming a double-sided in-mold molded product 1. [Selected Figure] Figure 6

Description

This invention relates to a method for manufacturing a double-sided in-mold molded product, and a double-sided in-mold molded product.

In-mold molding technology is a technology that integrally molds a transfer foil placed on the surface of a base body made of resin. The transfer film, which is made by laminating the transfer foil on a base film, is sandwiched inside an injection molding die, and molten resin is injected into the die to transfer the transfer foil onto the surface of the base. Double-sided in-mold molding technology is a technology that simultaneously molds the base and transfers the transfer foil to both the front and back sides of the base.

Conventional double-sided in-mold molding technology is described, for example, in the following Patent Documents 1 and 2.

JP 2003-053779 A Japanese Patent Application Laid-Open No. 62-227613

In conventional double-sided in-mold molding technology, two transfer films facing each other are placed in a cavity formed when the mold is closed, and molten resin is injected into the gap between the two transfer films. A through hole is formed in one of the two transfer films and is positioned outside the cavity, and the gate opens at the position of this through hole. Therefore, in molded products formed using conventional double-sided in-mold molding technology, the gate mark is formed outside the area that is actually used as the product.

Figure 1 shows an example of a molded product 100 immediately after molding using a conventional double-sided in-mold molding technique. As shown in Figure 1, the molded product 100 is molded into a shape in which the gate marks 102 are continuous outside the area 101a (hereinafter sometimes referred to as the "product area 101a") that will become the outer shape of the product when actually used as a product. In the example shown in Figure 1, the gate marks 102 include the side gate marks 102a that inject molten resin from the side of the product area 101a, the runner marks 102b that guide the molten resin to the side gate, and the gate tabs 102c, which correspond to the position of the gate of the mold during injection molding. The transfer foil peeled off from the base film of the transfer film is transferred to the entire front and back surfaces of the molded product 100, including the product area 101a. The molded product that will be the final product is one in which the areas other than the product area 101a have been removed by cutting the molded product 100 at the position shown by the dashed line in the figure.

Figure 2 shows an external view of molded product 101b, which is produced from molded product 100 shown in Figure 1 and used as a product. The outer periphery 104 of molded product 101b produced by the conventional double-sided in-mold molding technology is formed by cutting out the side gate mark 102a in molded product 100. Therefore, there is no transfer foil on the outer periphery 104 of molded product 101b. Figure 3 shows an enlarged cross section of the area indicated by circle 110 in Figure 2 taken along the arrow a-a. As shown in Figure 3, the outer periphery 104 of molded product 101b, which is formed by cutting out the gate mark 102, is an area where base 107 made of resin is exposed. In other words, with the conventional double-sided in-mold molding technology, the continuity of decoration between the front and back surfaces (105, 105) of molded product 101b is hindered, making it difficult to mold molded product 101b with excellent aesthetics.

In addition, in the conventional double-sided in-mold molding technology, resin material other than the product area 101a, such as the gate marks 102, is wasted in the molded product 100. Therefore, it is difficult to reduce the cost associated with the wasted resin material. In particular, when manufacturing a thin, wide-area plate-shaped molded product 101b as illustrated in Figs. 1 and 2, a so-called "film gate" is sometimes used, which is a side gate provided to surround the outer periphery of the product area so that the molten resin flows smoothly to every corner of the cavity during injection molding. In such a case, as shown in Fig. 1, a plate-shaped side gate mark 102a remains around the product area 101a, and more resin material is wasted. Since the molded product 100 larger than the product area 101a is injection molded, the mold becomes larger, and it is difficult to reduce the cost of the mold. The cost of the resin material and the mold makes it difficult to provide products at low prices. Wasted resin material is also undesirable from the viewpoint of resource conservation.

Therefore, one of the objectives of the present invention is to provide a method for manufacturing a double-sided in-mold molded product that is inexpensive and has a good appearance, and to provide said double-sided in-mold molded product.

In order to achieve the above object, one aspect of the present invention is a method for manufacturing a double-sided in-mold molded product, comprising the steps of:
A mold including a first mold member and a second mold member, and a first transfer film and a second transfer film each including a decorated transfer foil laminated on a base film, are used;
the first die member includes a gate;
the first transfer film has a through hole formed at a predetermined position;
a film installation step of laying the first transfer film over the first mold member and laying the second transfer film over the second mold member;
a mold closing step of closing the mold to form a cavity and sandwiching the first transfer film and the second transfer film in a facing state within the cavity between the first mold member and the second mold member;
an injecting step of injecting molten resin into the cavity;
In the film installation step, the first transfer film is installed so that the through hole is disposed at a predetermined position and a region including the through hole is in close contact with an inner surface of the first mold member;
In the mold closing step, the through hole is disposed in the cavity, and an inflow path for molten resin is formed, the inflow path communicating with the cavity from the gate via the through hole;
In the injection step, the molten resin is injected through the through hole into the region where the first transfer film and the second transfer film face each other, while filling the cavity with the molten resin, thereby transferring the transfer foil of the first transfer film and the transfer foil of the second transfer film to the outer surface of the molded product.
The method for producing a double-sided in-mold molded product is characterized by the above.

The method for manufacturing a double-sided in-mold molded product may also include an opening step in which an area including the gate mark is opened in a predetermined shape in the molded product molded in the injection step.

the first die member has a columnar recess that is continuous with the gate,
the through hole is formed in a shape that includes the opening of the recess,
In the injection step, molten resin is filled into the recess while being injected through the through hole into the area where the first transfer film and the second transfer film face each other, thereby forming a molded product having a protrusion that protrudes outward from the first transfer film through the through hole, which can also be a method for manufacturing a double-sided in-mold molded product.

In any of the above methods for manufacturing a double-sided in-mold molded product, the method may include a hole-punching machine disposed midway through the supply path of the first transfer film into the mold, and a hole-punching machine is used to form the through-holes. It is preferable to use a laser processing machine as the hole-punching machine in the method for manufacturing a double-sided in-mold molded product.

Another aspect of the present invention is a double-sided in-mold molded product having a decorated transfer foil arranged on the outer surface of a resin base,
The transfer foil has at least one through hole,
The outer surface of the substrate is covered with the transfer foil, and is exposed to the outside only at the position of the through hole.
The double-sided in-mold molded product is characterized by the above.

An opening is provided through the substrate,
The substrate may be a double-sided in-mold molded product, the outer surface of which is covered with the transfer foil and the inner surface of which is exposed at the opening.

A protrusion is formed on one main surface of the base body so as to protrude outward,
The base may be a double-sided in-mold molded product whose outer surface is covered with the transfer foil and is exposed to the outside only in the area where the protrusion is formed.

The substrate may be a plate-shaped double-sided in-mold molded product as described above, in which the outer periphery is covered with the transfer foil.

The present invention provides a method for producing a double-sided in-mold molded product that is inexpensive and has a good appearance, and the double-sided in-mold molded product. Other advantages will be explained below.

FIG. 1 is a diagram showing an example of a molded article that is the origin of a double-sided in-mold molded product molded by a conventional double-sided in-mold molding technique. FIG. 2 is a diagram showing a double-sided in-mold molded product produced from the molding shown in FIG. 1 . 3 is a diagram showing a cross section of a region including the outer peripheral edge of the double-sided in-mold molded product shown in FIG. 2. FIG. 1 is a diagram showing a product having a double-sided in-mold molded product according to a first embodiment. FIG. 2 is a diagram showing a disassembled state of a product including a double-sided in-mold molded product according to the first embodiment. 1A to 1C are diagrams showing the steps of a method for manufacturing a double-sided in-mold molded product according to a first embodiment. 1 is a diagram showing a molded product that is the origin of a double-sided in-mold molded product produced by a manufacturing method for a double-sided in-mold molded product according to a first embodiment. FIG. 1 is a diagram showing a cross section of a region including the outer peripheral edge of a double-sided in-mold molded product produced by a manufacturing method for a double-sided in-mold molded product according to a first embodiment. FIG. 1A to 1C are diagrams showing a procedure for forming through holes in a transfer film used in the manufacturing method for a double-sided in-mold molded product according to the first embodiment. 13A and 13B are diagrams showing a double-sided in-mold molded product according to a second embodiment. 11A to 11C are diagrams showing the steps of a method for manufacturing a double-sided in-mold molded product according to a second embodiment of the present invention. A figure showing a cross section of a region including the outer peripheral edge of a double-sided in-mold molded product in a second embodiment.

Embodiments of the present invention will be described below with reference to the attached drawings. Note that in the drawings used in the following description, the same or similar parts may be designated by the same reference numerals, and duplicate explanations may be omitted. Depending on the drawing, unnecessary reference numerals may be omitted in the explanation.

First Embodiment
<Double-sided in-mold molded products>

As an example of a double-sided in-mold molded product (hereinafter sometimes referred to as a "molded product") according to the first embodiment, a back cover of a smartphone is given. A smartphone is generally a rectangular flat plate with a display disposed on one main surface and a camera lens, etc. disposed on the other surface. The back cover is a thin plate-like member that covers the other surface while exposing the lens, etc., components to the outside.

In some cases, multiple types of smartphones with different surface decorations are available for the same model. For example, the same model may be available in different colors, the same model may have different letters or logos depending on the mobile communication company selling it, or may have special designs as limited edition items. Furthermore, in recent smartphones, one main surface is almost entirely covered by a display, so if a common housing with a display on this main surface is prepared, it is possible to have multiple types of smartphones with different decorations for the same model simply by replacing the back cover with a different decoration.

Figures 4 and 5 show a smartphone 10 equipped with a back cover 1 according to the first embodiment. As shown in the figures, the thickness direction of the rectangular, flat smartphone 10 is defined as the front-rear direction, and the front-rear directions are defined assuming that a display (not shown) is placed on the front side and the back cover 1 is attached to the rear side. Figure 4 is an external view of the smartphone 10 as seen from the rear, and Figure 5 shows the smartphone 10 shown in Figure 4 when separated into the smartphone body 11 and the back cover 1, which form a common housing.

The smartphone 10 shown in Figures 4 and 5 is equipped with a camera unit equipped with multiple lenses 12, and a rectangular flat area (hereinafter sometimes referred to as the "lens unit portion 13") in which the multiple lenses 12 are concentrated in a portion of the unit protrudes rearward from the back cover 1. The back cover 1 is provided with a rectangular opening 2 for exposing the lens unit portion 13 to the outside, and the back cover 1 is attached to the rear surface 14 of the smartphone body 11 by adhesive or the like.

Here, if the long side direction of the rectangle when the rectangular flat smartphone 10 is viewed from the front-to-back direction is defined as the up-down direction and the short side direction is defined as the left-to-right direction, the back cover 1 is rectangular when viewed from the front-to-back direction, and has an external shape in which the left and right edges are curved forward as shown in FIG. 5. In addition, in the back cover 1 illustrated in FIG. 5, a transfer foil with a design 5 such as a logo printed thereon is transferred to the rear surface of a base 7 made of colorless and transparent resin, and a transfer foil of a predetermined color is transferred to the front surface of the base 7. It also has an opening 2 for exposing the lens unit portion 13 described above.

As a result, even if the smartphone 10 is the same model, it is color-coded by the color of the transfer foil on the front surface 3 of the back cover 1, and is decorated with a different design 5 by the transfer foil on the back surface 4. The back cover 1 has the transfer foil arranged continuously around the entire outer edge 6 that forms the boundary between both the front and back surfaces (3, 4), and the resin base material of the base 7 is not exposed at this outer edge 6. In the back cover 1 shown in FIG. 5, the resin base material is exposed only at the inner edge 8 of the opening 2.

<Production Method>
As a manufacturing method of the double-sided in-mold molded product according to the first embodiment, the manufacturing procedure of the rear cover 1 shown in FIG. 4 and FIG. 5 is given. FIG. 6 shows the manufacturing procedure of the rear cover 1 in the order of (A) to (D). In the manufacturing procedure of the rear cover 1, a mold 20 consisting of two mold members (20a, 20b) is used, and the cross section of the mold members (20a, 20b) shown in FIG. 6 corresponds to the cross section of the rear cover 1 shown in FIG. 5 taken along the arrow b-b. In addition, in FIG. 6, the front-rear, left-right, and up-down directions of the rear cover 1 are defined as the front-rear, left-right, and up-down directions of the two mold members (20a, 20b). Here, the front mold member 20a (hereinafter sometimes referred to as the "front mold 20a") is a fixed mold, and the rear mold member 20b (hereinafter sometimes referred to as the "rear mold 20b") is a movable mold. Note that the up-down direction in the mold 20 shown in the figure does not indicate the up-down direction (vertical direction) according to gravity.

Regarding the manufacturing procedure for the rear cover 1, first, as shown in FIG. 6(A), a transfer film 30a (hereinafter sometimes referred to as "front side film 30a") for decorating the front surface 3 side of the rear cover 1 is laid over the front mold 20a. A transfer film 30b (hereinafter sometimes referred to as "rear side film 30b") for decorating the rear surface 4 side of the rear cover 1 is laid over the rear mold 20b.

The gate 21 is disposed on the front mold 20a side, and a through hole 31 is formed in advance in the front side film 30a at a position corresponding to the gate 21. The front side film 30a is also spanned in a state of being in close contact with the inner surface 22a of the front mold 20a, and as shown in FIG. 6(B), when the mold 20 is closed, the inner surface 22a of the front mold 20a and the inner surface 22b of the rear mold 20b form a cavity 23 that serves as an injection space for the molten resin 40. The front side film 30a and the rear side film 30b are also sandwiched between the front mold 20a and the rear mold 20b on the left and right outer sides of the cavity 23.

As described above, the front side film 30a is in close contact with the inner surface 22a of the front mold 20a with the through hole 31 facing the gate 21. The gate 21 also opens into the cavity 23. Therefore, after the mold 20 is closed, when the molten resin 40 is injected from the gate 21 as shown in FIG. 6(C), the molten resin 40 is guided through the through hole 31 of the front side film 30a into the gap between the front side film 30a and the rear side film 30b, which face each other in the cavity 23, and fills the cavity 23.

As shown in FIG. 6(D), when the molten resin 40 is filled into the cavity 23, the transfer foils of the front film 30a and the rear film 30b come into contact with the molten resin 40, and the contact surfaces become compatible. When the molten resin 40 cools, the transfer foils of the front film 30a and the rear film 30b peel off from their respective base films, and a molded product is formed in which the transfer foils are transferred to both the front and rear surfaces of the substrate. When the molten resin 40 has cooled sufficiently and solidified, the mold 20 is opened and the molded product is removed.

Figure 7 shows the molded product 50 after it has been removed from the mold 20. In the rear cover 1 shown in Figures 4 and 5, a gate mark 52 is molded in the area 51 that will become the opening 2 so as to protrude forward relative to the product area. Note that the gate mark 52 also includes parts, such as a runner, that are molded outside the product area when the molded product 50 is removed from the mold 20. By opening the area 51 that will become the opening 2 in this molded product 50 by cutting or the like, the above-mentioned rear cover 1 is completed.

Figure 8 shows an enlarged cross section of the area indicated by circle 200 in Figure 5 taken along the arrows b-b. According to the manufacturing method of the molded product of the first embodiment, the molded product 50 taken out of the mold 20 becomes the product area as it is, so that the transfer foil (32a, 32b) is continuous on both the front and rear surfaces (3, 4) even at the outer periphery 6 of the molded product used as a product such as the back cover 1, as shown in Figure 8, and the base 7 made of the resin material itself is not exposed at this outer periphery 6, so that a molded product with excellent appearance can be produced. Although the base 7 is exposed at the inner periphery 8 of the opening 2, this inner periphery 8 is for exposing to the outside some configuration that contacts the front 3 side of the back cover 1, such as the lens unit 13, so that the base 7 exposed at this inner periphery 8 does not spoil the appearance of the product such as the smartphone 10.

In addition, according to the manufacturing method of the molded product of the first embodiment, the molten resin 40 is guided into the cavity 23 from inside the product area during injection molding, so that a gate mark 52 is formed within the product area. This makes it possible to reduce the amount of resin material wasted. In addition, even in the case of a thin plate-shaped molded product such as the rear cover 1, the gate 21 is positioned inside the product area, so the molten resin 40 can flow to every corner of the cavity 23 without having to guide the molten resin 40 into the cavity 23 from the periphery of the product area.

In order to form the through holes 31 in the front side film 30a, for example, as shown in FIG. 9, among the paths through which the front side film 30a and the rear side film 30b are supplied to the front mold 20a and the rear mold 20b, respectively, a hole punching machine 60 may be installed in the middle of the supply path of the front side film 30a, as shown by the dashed arrows in the figure. This allows the hole punching operation (white arrow in the figure) for the front side film 30a, the installation operation of the front side film 30a to the front mold 20a, and the installation operation of the rear side film 30b to the rear mold 20b to be performed continuously. Then, after the rear side film 30b and the hole-punched front side film 30a are installed while being aligned with the rear mold 20b and the front mold 20a, respectively, the rear mold 20b may be moved to the front mold 20a side to close the mold 20. A press machine can be used as the hole punching machine 60, but if a laser machine is used, no cutting waste is produced from the front film 30a when the through holes 31 are formed, and contamination can be prevented.

Second Embodiment
Conventionally, some molded products have convex portions (hereinafter, sometimes referred to as "protrusions") such as ribs, bosses, and undercuts formed on the outer surface. For molded products having such protrusions, the surface on the outer surface of the molded product on which the protrusions are formed could not be decorated by in-mold molding. Therefore, for the surface on which the protrusions are formed, after molding the molded product, it was necessary to decorate the surface by printing or the like, or to attach a decorative film with through holes formed in accordance with the area where the protrusions are formed.

However, by applying the manufacturing method according to the first embodiment described above, it is possible to produce a molded product in which a protrusion is formed on one main surface by double-sided in-mold molding, and the transfer foil is transferred to the entire area of the outer surface, including the main surface, except for the area where the protrusion is formed. Below, we will list a molded product according to the second embodiment and a method for manufacturing the molded product according to the second embodiment, which is a molded product having a protrusion on one of its front or back surfaces, and the steps for manufacturing the molded product using double-sided in-mold molding technology.

<Molded products>
FIG. 10 shows an example of a molded product 71 according to the second embodiment. The molded product 71 shown in FIG. 10 is a rectangular plate, and a protruding portion 72 is formed on one main surface 73. Here, if the front and back directions of the molded product 71 are defined as the front-rear direction, the long side direction of the rectangle when viewed from the front-rear direction is defined as the up-down direction, and the short side direction is defined as the left-right direction, and the front-rear direction is defined as the protruding portion 72 protruding forward, the molded product 71 has a shape in which a region curved forward is continuous on the left and right edge sides of a flat rectangular planar region 75. The molded product 71 has cylindrical protruding portions 72 formed at the four corners of the rectangular planar region 75 on the front surface 73. The rear surface 74 is formed of a surface without any irregularities.

The illustrated molded product 71 is one of the components that make up a certain product. The product is, for example, made up of this molded product 71 and other components, and the other components have holes or the like into which the protrusions 72 of the molded product 71 are fitted. The product is assembled by fitting the protrusions 72 of the molded product 71 into the holes. In this way, the molded product 71 of the second embodiment can be assembled by simply fitting the protrusions 72 into holes or the like provided in the components to which the molded product 71 is to be attached. In the molded product 71 of the second embodiment, too, the transfer foil is arranged around the entire periphery of the outer periphery 76, and the resin base material that makes up the base 77 is not exposed. In the molded product 71 shown in FIG. 10, the resin base material is exposed only in the areas where the protrusions 72 are formed.

<Production Method>
Fig. 11 shows the manufacturing procedure of the molded product 71 shown in Fig. 10 in the order of (A) to (D). In the manufacturing procedure of the molded product 71, a mold 80 consisting of two mold members (80a, 80b) is used, and the cross section of the mold members (80a, 80b) shown in Fig. 11 corresponds to the cross section of the molded product 71 shown in Fig. 10 taken along the arrows c-c. In Fig. 11, the front-rear, left-right, and up-down directions of the molded product 71 are defined as the front-rear, left-right, and up-down directions of the two mold members (80a, 80b). As in the first embodiment, the mold 80 has a front mold 80a, which is a male mold, as a fixed mold, and a rear mold 80b, which is a female mold, as a movable mold.

First, as shown in Fig. 11(A), a transfer film 90a (hereinafter sometimes referred to as "front side film 90a") for transferring the decoration on the front surface 73 side of the molded product 71 is laid over the front mold 80a while being in close contact with the inner surface 83a of the front mold 80a. A transfer film 90b (hereinafter sometimes referred to as "rear side film 90b") for transferring the decoration on the rear surface 74 side of the molded product 71 is laid over the rear mold 80b.

The gate 81 is disposed on the front die 80a side. In addition, in the front die 80a, a recess 82 having a cylindrical inner surface is formed continuously behind the gate 81 to form the protrusion 72, and the gate 81 opens on the bottom surface of the recess 82. The front film 90a has through holes 91 formed at positions corresponding to the four protrusions 72, and the opening shape of each through hole 91 is a shape that includes the opening shape of the recess 82. When the front film 90a is draped over the front die 80a, the front film 90a is disposed so that the inner circumference of the through hole 91 surrounds the opening of the recess 82. As in the first embodiment, the hole punching machine 60 shown in FIG. 9 may be disposed on the supply path of the front film 90a, and the through hole 91 may be formed by the hole punching machine 60.

Next, as shown in FIG. 11(B), when the mold 80 is closed, the inner surface 83a of the front mold 80a and the inner surface 83b of the rear mold 80b form a cavity 84 that serves as an injection space for the molten resin 40. In addition, the front film 90a and the rear film 90b are sandwiched between the front mold 80a and the rear mold 80b on the left and right outer sides of the cavity 23.

After the mold 80 is closed, as shown in FIG. 11(C), molten resin 40 is injected into the cavity 84 formed in the mold 80. At this time, the molten resin 40 injected from the gate 81 fills the recess 82 on the front mold 80a side, and the molten resin 40 is guided through the through hole 91 in the front film 90a into the gap between the front film 90a and the rear film 90b that face each other in the cavity 84, filling the entire cavity 84.

As shown in FIG. 11(D), after the molten resin 40 is filled into the cavity 84, once the molten resin 40 has cooled sufficiently and solidified, the mold 80 is opened and the molded product formed into the shape of the cavity 84 is removed. The gate marks are then removed from the molded product, completing the molded product shown in FIG. 10.

Figure 12 shows an enlarged view of the c-c cross section of the area indicated by circle 300 in Figure 10. As shown in Figure 12, according to the manufacturing method of the molded product of the second embodiment, the transfer foil (92a, 92b) is continuous on both the front and rear surfaces (73, 74) even at the outer periphery 76 of the molded product 71, and the base 77 made of the resin material itself is not exposed at this outer periphery 6, making it possible to produce a molded product with excellent appearance. Although the base 77 is exposed only in the area where the protrusion 72 is formed, this protrusion 72 is inserted into a hole formed in another member, so it is not actually exposed to the outside. Therefore, the appearance of the product equipped with this molded product 71 is not marred by the protrusion 72 where the base 77 is exposed.

===Other Examples===
In the manufacturing method of the molded product according to each of the above-mentioned embodiments, the final molded product is completed by removing the gate mark from the molded product, but by using a mold with a pin gate or a hot runner, no gate mark remains when the mold is released, and the molded product itself removed from the mold can be used as the molded product. That is, a molded product can be produced in which there is no opening 2 or protrusion 72, a transfer foil is arranged on the outer periphery, and a transfer foil having a through hole is arranged at a position corresponding to the gate. Of course, the final molded product may be produced by forming the opening 2 in a molded product molded by a pin gate or a hot runner.

In each of the above embodiments, the number of gates (21, 81) provided in the front mold (20a, 80a) is not limited to one. It is also possible to provide multiple gates (21, 81) and provide through holes (31, 91) in the front side film (30a, 80a) corresponding to each gate (21, 81).

When molding the molded product (1, 71), the entire area of the front side film (30a, 80a) in which the through hole (31, 91) is formed does not have to be in close contact with the inner surface (22a, 83a) of the front mold (20a, 80a). If at least the area surrounding the through hole (31, 91) is in close contact with the inner surface (22a, 83a) of the front mold (20a, 80a), the molten resin 40 can be guided into the cavity (23, 84) through the through hole (31, 91). As a result, for example, in the procedure of the manufacturing method of the molded product according to the first embodiment shown in FIG. 6, the inner surface shape is such that the front mold 20a side is a male mold and the rear mold 20b side is a female mold, but the front mold 20a side can also be a female mold.

In the manufacturing method of the molded product according to each of the above embodiments, the front mold (20a, 80a) on which the front side film (30a, 90a) on which the through hole (31, 91) is formed is stretched is a fixed mold, but the front mold (20a, 80a) may be a movable mold if the front side film (30a, 90a) can be kept in close contact with the inner surface (22a, 83a) of the front mold (20a, 80a) by suction or the like.

The planar shape of the through hole (31, 91) is not limited to a circle, as long as it surrounds the opening shape of the gate 21 and the recess 82.

In the second embodiment, the protrusion 72 formed on the molded product 71 is not limited to a cylindrical shape, but may be a prismatic shape or a truncated cone shape tapering forward. Furthermore, the protrusion 72 may be a rib or an undercut. In the case of a rib, a groove that is continuous with the gate 81 is formed on the front mold 80a side, and a slit-shaped through hole 91 that encompasses the opening of this groove is formed in the front side film 90a. If a slide core that can enter and exit inside the columnar recess 82 is provided in the front mold 80a, an undercut can also be formed.

In the second embodiment, the gate 81 is not limited to being provided at the bottom of the recess 82, but may be provided on the inner peripheral surface of the recess 82. In any case, it is sufficient that the gate 81 is formed continuously with the recess 82. In the manufacturing method of the molded product according to each of the above embodiments, not limited to the second embodiment, when the front side film (30a, 90a) is bridging the front mold (20a, 80a), the front side film (30a, 90a) is positioned so that a path is formed for guiding the molten resin 40 to the cavity (23, 84) through the through hole (31, 91) in the procedure of closing the mold (20, 80) and injecting the molten resin 40 from the gate (21, 81) following the bridging operation.

To perform double-sided in-mold molding of a molded product having both an opening 2 and a protrusion 72, the manufacturing method of the molded product according to the first embodiment can be combined with the manufacturing method of the molded product according to the second embodiment.

The molded product (1, 71) is not limited to a plate-shaped molded product. According to the manufacturing method of the molded product (1, 71) of each embodiment, if there is a portion corresponding to the opening 2 or the protruding portion 72, even if the molded product has a thickness, the transfer foil (32a, 32b, 92a, 92b) can be placed on the entire surface except for the inner surface of the opening 2 and the protruding portion 72.

1, 71, 101b Double-sided in-mold molded product (molded product), 2 Opening,
3, 73 front surface of molded product, 4, 74 rear surface of molded product,
6, 76, 104 Outer periphery of molded product, 7, 77, 107 Base, 8 Inner periphery of opening,
20, 80 Mold, 20a, 20b, 80a, 80b Mold member, 21, 81 Gate, 23, 84 Cavity, 30a, 30b, 90a, 90b Transfer film,
31, 91 through hole, 32a, 32b, 92a, 92b, 106 transfer foil,
40 Molten resin, 50, 100 Molded product, 52, 102 Gate mark, 72 Protruding portion,
82 Recess

Claims (9)

A method for manufacturing a double-sided in-mold molded product, comprising the steps of:
A mold including a first mold member and a second mold member, and a first transfer film and a second transfer film each including a decorated transfer foil laminated on a base film, are used;
the first die member includes a gate;
the first transfer film has a through hole formed at a predetermined position;
a film installation step of suspending the first transfer film over the first mold member and suspending the second transfer film over the second mold member;
a mold closing step of closing the mold to form a cavity and sandwiching the first transfer film and the second transfer film in a facing state within the cavity between the first mold member and the second mold member;
an injecting step of injecting molten resin into the cavity;
In the film installation step, the first transfer film is installed so that the through hole is disposed at a predetermined position and a region including the through hole is in close contact with an inner surface of the first mold member;
In the mold closing step, the through hole is disposed in the cavity, and an inflow path for molten resin is formed, the inflow path communicating with the cavity from the gate via the through hole;
In the injection step, the molten resin is injected through the through hole into the region where the first transfer film and the second transfer film face each other, while filling the cavity with the molten resin, thereby forming a molded product in which the transfer foil of the first transfer film and the transfer foil of the second transfer film are transferred to the outer surface.
A method for producing a double-sided in-mold molded product. The method for manufacturing a double-sided in-mold molded product according to claim 1, further comprising an opening step for opening an area including a gate mark in a predetermined shape in the molded product molded in the injection step. the first die member has a columnar recess that is continuous with the gate,
The through hole is formed in a shape that includes the opening of the recess,
In the injection step, a molten resin is injected into a region where the first transfer film and the second transfer film face each other through the through hole while filling the recess, thereby forming a molded product having a protruding portion protruding outward from the first transfer film through the through hole.
The method for manufacturing a double-sided in-mold molded product according to claim 1 . The method for manufacturing a double-sided in-mold molded product according to any one of claims 1 to 3, characterized in that it includes a hole-making step in which a hole-making machine is installed midway along the supply path of the first transfer film into the mold, and the through-holes are formed by the hole-making machine. The method for manufacturing a double-sided in-mold molded product according to claim 4, characterized in that a laser processing machine is used as the hole-punching machine. A double-sided in-mold molded product having a transfer foil on the outer surface of a resin base,
The transfer foil has at least one through hole,
The outer surface of the substrate is covered with the transfer foil, and is exposed to the outside only at the position of the through hole.
A double-sided in-mold molded product characterized by: A double-sided in-mold molded product having a transfer foil on the outer surface of a resin base,
An opening is provided through the substrate,
The outer surface of the substrate is covered with the transfer foil and is exposed on the inner surface of the opening.
A double-sided in-mold molded product characterized by: A double-sided in-mold molded product having a transfer foil on the outer surface of a resin base,
A protrusion is formed on one main surface of the base body so as to protrude outward,
The outer surface of the substrate is covered with the transfer foil, and is exposed to the outside only in the region where the protrusion is formed.
A double-sided in-mold molded product characterized by: The double-sided in-mold molded product according to any one of claims 6 to 8, characterized in that the base is plate-shaped and the outer periphery is covered with the transfer foil.

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