JPH09131755A - Insert molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wrinkles from developing at the drawn part of a decorative sheet in its drawn shape during the insert molding of the decorative sheet and synthetic resin. SOLUTION: By forming recessed parts, projected parts or projecting beads at a portion, which corresponds to a drawn portion in the corner portion of a decorative sheet 50, of a mold 14, wrinkles are prevented from developing at the corner portion of the decorative sheet 50 due to the formed uneven indications 71, recessed beads 72 or projected parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insert molding method, and in particular, a decorative sheet is arranged along the inner surface of a cavity of a mold, the mold is closed and a molten resin is injected into the cavity to form an outer surface. The present invention relates to an insert molding method for producing a molded body in which a decorative sheet is joined to the.

[0002]

2. Description of the Related Art For example, as disclosed in Japanese Patent Laid-Open No. 63-189233, a synthetic resin leather having a leather-patterned surface layer is compositely molded in a state of being welded onto a synthetic resin molding. The insert molding method is known. In such a method, a decorative sheet constituting the synthetic resin leather is arranged at a predetermined position along the inner surface of the mold cavity, the mold is closed, and the molten resin is injected into the cavity. Then, the synthetic resin molded body is molded with the decorative sheet bonded to the outer surface.

[0003]

When the insert molding method using such a decorative sheet is applied to, for example, a cabinet of electronic equipment, a molded body having an outer surface covered with synthetic leather can be obtained. . However, when the decorative sheet is applied to a rectangular parallelepiped cabinet, the decorative sheet has to be squeezed at the peripheral edge, which causes a problem that the decorative sheet easily causes wrinkles at the peripheral edge of the cabinet.

In order to prevent such wrinkles, it has been necessary to reduce the curvature of the peripheral portion of the cabinet, particularly the corner portion, and to make the shape have a large radius of curvature.
However, such a structure causes restrictions on the design of the cabinet or restrictions on the design. Therefore, the decorative sheet is heat-pressed in advance, and the decorative sheet is squeezed in the portion corresponding to the corner portion of the cabinet, and the decorative sheet preformed in such a shape is placed in the mold. Thus, it is possible to prevent wrinkles from being generated at the corners. However, the above measures not only increase the number of steps but also require an apparatus for pre-processing the decorative sheet, which leads to an increase in the cost of the molded product.

The present invention has been made in view of the above problems, and in an insert molding method using a decorative sheet, when it is applied to a cabinet of an electronic device or the like, particularly at a corner portion thereof. It is an object of the present invention to provide an insert molding method in which a decorative sheet is free from wrinkles and can be molded without special pre-processing.

[0006]

According to the present invention, a decorative sheet is arranged along the inner surface of a cavity of a mold, the mold is closed, a molten resin is injected into the cavity, and the outer surface is subjected to the above-mentioned treatment. In an insert molding method for producing a molded body to which a decorative sheet is bonded, unevenness is formed at a position substantially corresponding to a corner portion of the cavity of the mold, and the unevenness is bonded to the outer surface of the molded body. The present invention relates to an insert molding method, characterized in that a protrusion or a recess is formed in a peripheral portion of the decorated sheet at a corner portion of the molded body. The wrinkles of the decorative sheet are absorbed by such protrusions or recesses.

The projections or recesses may be formed at the corners of the decorative sheet where the decorative sheet is squeezed due to the unevenness of the mold.

A protrusion or a recess formed on the decorative sheet may constitute a display.

The protrusions formed on the decorative sheet may form the legs of the molded body.

[0010]

FIG. 1 shows a molding apparatus used in an insert molding method according to an embodiment of the present invention. This molding apparatus comprises an upper movable platen 11 and a lower fixed platen 12. And are provided respectively. The upper mold 13 is fixed to the lower part of the movable platen 11, and the lower mold 14 is fixed to the upper part of the fixed platen 12. A cavity 15 is formed along the joining surface of the pair of upper and lower molds 13 and 14, and a molten resin is injected into such a cavity 15 to perform injection molding.

Slide blocks 17, 18, 19, which move so as to be orthogonal to the pair of upper and lower molds 13, 14.
20 are arranged as shown in FIGS. These slide blocks 17, 18, 19, 20 are provided with slide cores 21, 22, 23, 24 at their tip ends, respectively. As shown in FIGS. 5 and 6, these slide cores 21 to 24 receive the peripheral edge of the decorative sheet 50, which will be described later, at the peripheral edge of the cavity 15.

Next, the structure for opening and closing the slide blocks 17 to 20 equipped with the slide cores 21 to 24 at their tips will be described.
As shown in FIG. 2, actuating plates 28 are attached to the outer side surface of the No. 1 at the four sides thereof. A pair of arms 29 extends from the tip end side of these operating plates 28. A cam surface 30 is formed inside the arm 29, and a cam surface 31 is formed outside the arm 29.

A recess 32 is formed between the pair of arms 29, and a pusher 33 is attached to the recess 32. The presser 33 has a cam surface 34 formed inside and a cam surface 35 formed outside.

On the other hand, the slide cores 21-
An inclined surface 38 is formed on the outer surface of each of the slide blocks 17 to 20 supporting 24, and is pressed by the cam surface 30 inside the arm 29. Further, a vertical surface 39 is formed between the inclined surfaces 38.
9 is pressed by the cam surface 34 inside the pressing element 33. A pullback piece 40 is attached to the vertical surface 39. The inner surface of the piece 40 is pressed by the outer cam surface 35 of the pressing element 33, whereby the slide block 20 is pulled back to open the slide core 24.

On the outer surface of the fixed platen 12, receiving blocks 43 are fixedly attached to the four sides thereof. The receiving block 43 is provided with an inclined surface 44 on the inner side thereof, and the inclined surface 44 is provided on the outer cam surface 31 of the arm 29 of the operating plate 28.
Is pressed.

The inner surface of the lower mold 14 of the pair of molds 13 and 14 which are openably and closably combined with each other to form the cavity 15 has its inner surface as shown in FIGS. 9 and 10. A display concave portion 67, a display convex portion 68, and a ridge 69 are formed in the corner portion of the concave portion. Both the concave portion 67 and the convex portion 68 are for forming an indication on the molded body. In addition, the concave portion 67, the convex portion 68, and the protrusion 69 are all provided in the mold 14.
The decorative sheet 5 is provided with unevenness for absorbing wrinkles generated when the decorative sheet 50 arranged above is squeezed at the corners.
It is for forming 0.

In the above structure, when the movable platen 11 shown in FIG. 1 is lowered, the movable platen 11 is lowered.
The upper mold 13 attached to the lower part is lowered and joined to the lower mold 14 to form a cavity 15. This cahidi 15 forms an injection space for the molten resin.

The operating plate 28 descends in conjunction with the descending movement of the movable platen 11. As the operating plate 28 descends, the inner cam surface 34 of the pusher 33 attached to the operating plate 28 comes into contact with the upper edge portion of the vertical surface 39 of the slide block 20, and thereby the slide block. 20 is moved to the left in FIG. Therefore, the timing of movement of the slide block 20 and the slide core 24 is determined by the height of the pusher 33 attached to the operating plate 28 or the shape of the cam surface 34 of the pusher 33.

When the movable platen 11 is completely lowered with respect to the fixed platen 12, the cam surface 30 inside the arm 29 of the operating plate 28 is provided on the outer surface of the slide block 20, as shown in FIG. The inclined surface 38 is pressed, and the final positioning of the slide block 20 is performed. That is, the position shown in FIG. 4 is the position where the slide core 24 is most advanced and closed.

In conjunction with the upward movement of the movable platen 11, the cam surface 35 on the outside of the pressing element 33 attached to the operating plate 28 presses the pullback piece 40, whereby the molds 13 and 14 are moved. In conjunction with opening, the slide block 20 is moved to the right as shown in FIG. 3 to open the slide core 24.

Particularly in the insert molding by this device, the timing of pressing the slide blocks 17 to 20 by the cam surface 34 inside the pressing element 33 of the operating plate 28 is adjusted, whereby the four slide cores 21 are adjusted.
~ 24 is adjusting the closing timing.

As shown in FIG. 11, for example, the decorative sheet 50 is made of a vinyl chloride resin sheet 51 on the outer surface side thereof, and the outer surface of the decorative sheet 50 is made into artificial leather by forming irregularities imitating leather. . Then, such a vinyl chloride resin sheet 51 is provided with a non-woven fabric 53 via an adhesive layer 52.
Is joined to. Such a decorative sheet 50 is shown in FIG.
As shown in (1), it is punched into a shape slightly larger than the size of the front cabinet of an electronic device, for example, a radio receiver, and the openings 56 and various small holes are punched if necessary.

As shown in FIG. 7, the decorative sheet 50 punched into a predetermined shape is arranged in the recess of the lower mold 14. A protrusion 57 corresponding to the opening 56 of the decorative sheet 50 is formed in the lower mold 14,
When the opening 56 of the decorative sheet 50 receives the protrusion 57, the decorative sheet 50 is positioned on the inner surface of the lower mold 14. Moreover, as shown in FIGS. 7 and 8, the decorative sheet 50 can be received by the protrusion 46 formed at the edge portion on the leading end side of the slide cores 21 to 24 whose peripheral portions are closed. And the decorative sheet 5 by such protrusions 46
0 is held such that its peripheral portion is bent inward.

In such a state, the molten resin is injected into the cavities 15 of the upper and lower molds 13 and 14 which are closed. For example, a melt of ABS resin at 220 to 230 ° C. is injected. At this time, the molds 13 and 14 may be heated to, for example, 70 to 80 ° C. in advance. As a result, FIG.
Front cabinet 60 made of ABS resin as shown in
Is injection molded. Such a cabinet 60 is taken out of the mold by raising the movable platen 11 and opening the molds 13 and 14.

The molded cabinet 60 is the mold 1 described above.
The decorative sheet 50, which is previously arranged between 3 and 14, is injection-molded in a state of being joined to the outer surface. As shown in FIG. 16, such a front cabinet 60 is combined with a rear cabinet 61 to form a radio receiver casing. The rear cabinet 61 also has a structure in which the decorative sheet 50 is joined to the outer surface of the rear cabinet 61, and is manufactured by the same method as the front cabinet 60.

Prior to molding, the decorative sheet 50 has a thickness of about 1.3 mm. And decorative sheet 5
When molded with 0 bonded, the thickness is 1.5 mm
The cabinet 60 will be molded. Here, the decorative sheet 50 is compressed to have a thickness of about 0.5 mm. The thus-decorated decorative sheet 50 covers the outer surface of the cabinet 60 with the portion of the non-woven fabric layer 53 side bonded to the resin layer, and the thickness of the resin layer of the cabinet 60 at this time. Is about 1.0 mm.

On the outer peripheral surfaces of the molded cabinets 60 and 61, as shown in FIGS. 13 to 16, line grooves 63 and 64 are formed near their joints, respectively. These line grooves 63 and 64 are formed by the projections 46 formed at the edge portions on the tip side of the four slide cores 21 to 24 used in combination with the upper and lower molds 13 and 14. .

It should be noted here that the peripheral edge portion of the decorative sheet 50 is the slide cores 21 to 21.
The peripheral edge portion of the decorative sheet 50 is formed in a state of being bent inward by the protrusion 46 on the front end side of 24, as shown in FIG.
As shown in FIGS. 4 to 16, the edge portion is the groove 6
As it is bent inward along the grooves 3 and 64, it is molded in a state of being joined to the cabinets 60 and 61. Therefore, the edge portion of the peripheral portion of the decorative sheet 50 is not exposed on the outer surfaces of the cabinets 60 and 61, so that the appearance of the cabinets 60 and 61 is not impaired.

In this way, a metal mold is provided at the corner of the outer surface of the cabinet 60 formed by molding the decorative sheet 50 bonded to the outer surface and at the corner where the decorative sheet 50 is bonded. The display concave portion 67 or the display convex portion 68 of 14 forms a convex display 71 or a concave display 71. These indications 71 also serve as wrinkle absorbing means for absorbing wrinkles particularly generated in the narrowed portion of the decorative sheet 50.

Further, as shown in FIGS. 13 and 14, the concave ridges 72 are formed on the outer surface of the cabinet and below the concave ridges 69 of the mold 14 as shown in FIGS. 13 and 14. Become. These recessed strips 72 are decorative sheets 5
Wrinkles caused by squeezing the 0 corner portion are absorbed. A ridge may be formed instead of the recess 72.

As described above, in the insert molding method according to this embodiment, the projections 71 or the concave displays 71 are formed on the peripheral portion of the decorative sheet 50, especially at the corners of the molded body 60. Alternatively, the concave line 72 is formed. Wrinkles that occur when the decorative sheet 50 is squeezed at the corners of the molded body 60 are absorbed by the display 71 and the concave lines 72. Therefore, it is possible to mold the cabinet 60 having a complicated shape, and it is possible to mold a molded body having a narrowed shape and the decorative sheet 50 joined to the outer surface of the narrowed portion without generating wrinkles. It will be possible. Therefore, the defective rate of the molded product 60 is reduced and the mass productivity is improved. Further, it is not necessary to preliminarily perform the pre-processing for drawing on the decorative sheet 50, which makes it possible to shorten the process and omit the equipment for the pre-processing.

FIG. 16 shows a state in which such a cabinet 60 is combined with a cabinet 61 on the opposite side. In the cabinet 61 on the opposite side, the decorative sheet 50 is joined to the outer surface of the cabinet 61, and the corner portion of the cabinet 61 where the decorative sheet 50 is squeezed is wrinkled when the decorative sheet 50 is squeezed. A projection 73 for absorbing the is formed. Therefore, the protrusions 73 do not cause wrinkles in the corners of the decorative sheet 50 even in the cabinet 61 on the back side, the defective rate at the time of molding the molded body 61 is reduced, and the mass productivity is improved. It becomes possible to provide an inexpensive cabinet 61.

17 and 18 show another embodiment, in which a display 71 is formed on the upper portion of the cabinet 60, and the legs of the cabinet 60 are provided on the lower corner portion. The protrusions 73 constituting the above are formed, and wrinkles are absorbed particularly at the left and right corners below the decorative sheet 50 by such protrusions 73. Therefore, the protrusion 73 for absorbing the wrinkles on the lower side also serves as the leg portion, and it is possible to prevent the formation of meaningless unevenness. In addition, the protrusions 73 that constitute such a leg portion include the slide cores 21 to 24.
Are formed by the recesses formed in the corresponding slide cores.

Even with the projections 73 forming the leg portions, it is possible to obtain the same effects as the above-described embodiment. Moreover, since meaningless unevenness is not formed in the cabinet 60, the design of the cabinet 60 is not impaired.

[0035]

Industrial Applicability According to the present invention, unevenness is formed at a position corresponding to a corner portion of a cavity of a mold, and a peripheral portion of a decorative sheet is joined to the outer surface of a molded body by the unevenness. The protrusions or recesses are formed at the corners of the body.

Therefore, such recesses or protrusions effectively prevent the generation of wrinkles at the peripheral portion of the decorative sheet and at the corners of the molded body.

According to the structure in which the protrusions or recesses are formed at the corners of the decorative sheet that are squeezed due to the unevenness of the mold, the wrinkles of the decorative sheet are more effective especially at the squeezed corners. And surely prevented.

According to the structure in which the projections or recesses formed on the decorative sheet make an indication, the projections or recesses formed on the decoration sheet can both serve as the display and the prevention of wrinkles. In particular, it becomes possible to form a predetermined indication on the outer surface of the molded body by the projection or the recess for preventing wrinkles.

According to the constitution in which the protrusions formed on the decorative sheet form the legs of the molded body, the leg portions are formed on the molded body by the protrusions for preventing the wrinkles at the corners of the decorative sheet. Thus, the wrinkles are prevented and the legs are formed.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a mold used for an insert molding method.

FIG. 2 is an exploded perspective view showing a structure for opening and closing a slide block.

FIG. 3 is a vertical sectional view of the main part.

FIG. 4 is a vertical sectional view showing a state where the slide block is completely pushed in.

FIG. 5 is a cross-sectional view of a mold with a slide core opened.

FIG. 6 is a cross-sectional view of a mold in which four slide cores are closed together.

FIG. 7 is a longitudinal sectional view of a closed mold.

FIG. 8 is a vertical cross-sectional view of the closed mold in the width direction.

FIG. 9 is a plan view of a lower die.

FIG. 10 is a longitudinal sectional view of the same.

FIG. 11 is an enlarged cross-sectional view of a decorative sheet.

FIG. 12 is a perspective view of the same.

FIG. 13 is an external perspective view of a molded cabinet.

FIG. 14 is a vertical sectional view of a cabinet.

FIG. 15 is a vertical cross-sectional view of the cabinet in the width direction.

FIG. 16 is a vertical cross-sectional view of a state in which upper and lower cabinets are combined.

FIG. 17 is a front view of a cabinet according to another embodiment.

FIG. 18 is a vertical sectional view of the cabinet.

[Explanation of symbols]

 11 Movable Platen 12 Fixed Platen 13 Mold (Upper) 14 Mold (Lower) 15 Cavity 17-20 Slide Block 21-24 Slide Core 28 Actuation Plate 29 Arm 30 Cam Surface (Inside) 31 Cam Surface (Outside) 32 Recess 33 Pusher 34 Cam surface (inner side) 35 Cam surface (outer side) 38 Inclination surface 39 Vertical surface 40 Pullback piece 43 Receiving block 44 Inclined surface 46 Projection portion 50 Decorative sheet 51 Vinyl chloride resin sheet 52 Adhesive layer 53 Nonwoven fabric 56 Opening 57 Projection 60 Cabinet (upper side) 61 Cabinet (lower side) 63 Groove (upper side) 64 Groove (lower side) 67 Recessed portion for display 68 Convex portion for display 71 Displayed portion 72 Recessed portion 73 Projected portion

Claims (4)

[Claims] 1. A molded body in which a decorative sheet is arranged along the inner surface of a cavity of a mold, the mold is closed, a molten resin is injected into the cavity, and the decorative sheet is bonded to the outer surface. In the insert molding method so as to manufacture, the unevenness is formed at a position substantially corresponding to the corner portion of the cavity of the mold, and the decorative sheet is joined to the outer surface of the molded body by the unevenness. The insert molding method is characterized in that a protrusion or a recess is formed at a corner portion of the molded body which is a peripheral portion. 2. The insert molding method according to claim 1, wherein a protrusion or a recess is formed in a corner portion of the decorative sheet that is narrowed by the unevenness of the mold. 3. The insert molding method according to claim 1, wherein a projection or a recess formed on the decorative sheet constitutes a display. 4. The insert molding method according to claim 1, wherein the protrusion formed on the decorative sheet constitutes a leg of a molded body.