JP3719660B2 - Injection mold for molded article with film and method for producing molded article with film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection mold for a molded article with a film in which a resin film is disposed in a pair of molds and a molten resin is injection-molded onto the resin film, and in particular, a film that facilitates removal of the molded article from the mold The present invention relates to an injection mold for a molded article and a method for producing a molded article with a film using the mold.
[0002]
[Prior art]
As a resin molded product having a plurality of protrusions such as a pushbutton sheet of a cellular phone, the plurality of protrusions 21 are connected to each other at the base portion 22 as shown in FIG. A film in which the outer surface and the base portion 22 are made of a continuous resin film 23, each of the protrusions 21 is filled with a resin 24, and characters and the like are printed on the resin film 23 on the top portion 21a of the protrusion 21. A molded product is known.
[0003]
In order to manufacture such a molded article with a film, an injection mold 20 as shown in FIG. 8 is used. For example, in Japanese Patent No. 3136388, a cavity side mold 26 having a cavity recess 25 and A resin film 23 pre-formed according to a plate shape or a product shape is disposed between the spool 27 and the core side mold 29 on which the gate portion 28 and the like are disposed, and the molten resin 24 is injected from the gate portion 28. Thus, the resin film 23 is stretched and deformed by the heat and injection pressure of the molten resin, and the resin film 23 and the resin 24 are integrated while being closely adhered to the inner surface of the cavity recess 25.
[0004]
In such an injection mold 20, in order to remove the molded product from the mold after molding, the cavity side mold 26 is opened from the core side mold 29, and then an operator holds a part of the resin film 23. Then, the protruding portion 21 is extracted from the cavity concave portion 25, or compressed air is blown out from the cavity-side mold 26 to the resin film 23.
[0005]
In general, an injection molded product that does not use the resin film 23 is provided with a protruding pin or the like in a mold, and the molded product is directly taken out by this protruding pin.
[0006]
[Problems to be solved by the invention]
However, in such an injection mold 20, when a molded product is taken out, both are subjected to a pressing force and peeling force locally, so that the molding is in a state of being easily deformed immediately after being opened and before being completely cured. There was a problem that the product was deformed by the local force.
[0007]
In particular, in a molded article with a film having a plurality of protrusions 21, all the protrusions 21 must be taken out from the cavity recess 25 of the mold, and can be easily taken out while uniformly applying force to the entire resin film 23. It had the problem of not.
[0008]
Therefore, an object of the present invention is to provide an injection mold for a molded product with a film that can easily take out a molded product and prevent deformation of the molded product at the time of taking out.
[0009]
[Means for Solving the Problems]
In order to solve the problems as described above, the invention according to claim 1 is a pair of molds including a cavity side mold having two or more concave portions of the final product shape and a core side mold for closing the concave portions. An injection mold for a molded article with a film, in which a resin film is disposed between and the molten resin and the resin film are integrated while the resin film is in close contact with the wall surface of the recess by injecting the molten resin. The core-side mold includes a base plate in which a gate portion for injecting the molten resin corresponding to the two or more recessed portions is integrated, and a stripper disposed on the recessed portion side of the base plate and movable in the mold opening direction. and a plate, said stripper plate has a convex portion opposite to continuous annularly respective opening edge of the two or more positions of the recesses, the convex portion from the inside of the opening edge Has a width of up to the side, by far the part of the convex portion during mold closing and the opening peripheral edge part is provided so as to contact the annular, the core mold half from said cavity side mold type After the opening, the stripper plate is moved to the concave portion side to be separated from the base plate, thereby forming an injection mold for a molded article with a film.
[0010]
According to a second aspect of the invention, in addition to the configuration of the first aspect, the height of the convex portion is 20% to 70% of the thickness of the resin film, and a part of the convex portion. The width of the portion where the opening peripheral edge abuts annularly is set to be 2 mm or less .
[0012]
According to a third aspect of the present invention, there is provided a manufacturing method according to claim 1 , wherein the mold according to claim 1 or 2 is used, and the resin film molded body that has been molded into a final product shape in advance is a cavity having a concave portion of the final product shape. Inserting into the tee side mold and closing the mold , injecting the molten resin from the gate portion , and integrating the molten resin and the resin film; and pulling the core side mold away from the cavity side mold. And opening the mold, and slid the stripper plate toward the recess and pulling it away from the base plate to cut the gate part and remove the molded product with film from the core side mold. Features.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
FIG. 1 shows an injection mold according to an embodiment of the present invention.
[0015]
The injection mold 1 includes a cavity-side mold 3 and a core-side mold 4, and the cavity-side mold 3 is a recess having a final product shape corresponding to a plurality of protrusions 21 as shown in FIG. 3a and the outer surface 3b which continues between each recessed part 3a, and the wall surface 3c of the recessed part 3a becomes the shape of the outer surface of a final product.
[0016]
The core side mold 4 includes a base plate 5 connected to the molten resin supply side, and a stripper plate 6 adjacent to the base plate 5 and facing the cavity side mold 3. Further, the core-side mold 4 is accommodated in a through hole 7 that penetrates the base plate 5 and the stripper plate 6, one end is locked and integrated with the base plate 5, and the other end is a cavity. It has a gate bush 8 exposed to the concave portion 3a side of the side mold 3. The outer surface 6c of the stripper plate 6 and the end surface 8c of the gate bush 8 facing the recess 3a correspond to the bottom shape of the product.
[0017]
The space surrounded by the wall surface 3 c of the recess 3 a of the cavity side mold 3, the outer surface 6 c of the stripper plate 6 of the core side mold 4, the through hole 7 and the end face 8 c of the gate bush 8 is filled with the filling resin 2. .
[0018]
FIG. 2 shows a cross-sectional view of the vicinity of the gate bush 8 of the injection mold 1.
[0019]
The gate bush 8 has a spool portion 8a and a gate portion 8b which are continuous from the molten resin supply side, and one of the gate bushes 8 is a cylindrical body 11 protruding in a column shape from the base plate 5, and a gate portion is provided on one end face 8c thereof. 8b is arranged. Further, a flange portion 8f locked to the base plate 5 is provided on the outer periphery on the other end portion 8e side which is the supply side. The through hole 7 that accommodates the gate bush 8 is provided so as to be oriented in the mold opening direction, and prevents the molten resin from entering between the gate bush 8 and the through hole 7 and allows gas to enter. A radial gap 13 having a width of, for example, about 5 to 25 μm is provided, and the outside of the stripper plate 6 communicates with the outside of the base plate 5.
[0020]
Further, in this injection mold 1, an annular continuous convex portion 6 a is opposed to the opening peripheral portion 3 e of the concave portion 3 a of the cavity side mold 3 on the outer surface 6 c of the stripper plate 6 outside the through hole 7. Is provided. A preform molded body 10 made of a resin film is firmly held between the convex portion 6 a and the opening peripheral edge portion 3 e of the cavity side mold 3.
[0021]
In this convex part 6a, it is preferable to provide the width of the clamping part which opposes the opening peripheral part 3e and clamps the preform molded object 10 to 2 mm or less. This is because the preform molded body 10 can be sandwiched more uniformly by the opening peripheral edge portion 3e. Here, the convex portion 6a further has a width from the inside to the outside of the opening peripheral edge portion 3e of the concave portion 3a.
[0022]
Moreover, it is preferable that the height of the convex part 6a shall be 20%-70% of the thickness of a resin film. When this height exceeds 70% of the thickness of the resin film, the gap between the cavity side mold 3 and the stripper plate 6 becomes large at a portion other than between the convex portion 6a and the opening peripheral edge portion 3e. The resin film is slack and easily deforms into a waveform. On the other hand, if it is less than 20% of the thickness of the resin film, if the thickness of the preform molded body 10 becomes non-uniform in the pre-process such as printing or molding, between the convex portion 6a and the opening peripheral portion 3e. The preform 10 cannot be securely clamped, and the filled resin 2 is likely to flow out.
[0023]
In the injection mold 1, the cavity side mold 3 and the stripper plate 6 can be moved in the mold opening direction by a guide member, a driving device, or the like (not shown).
[0024]
As an example, a method for manufacturing a pushbutton sheet for a mobile phone, which is a molded article with a film, will be described using the injection mold 1 having the above-described configuration.
[0025]
Here, in a state where a resin film is sandwiched between the cavity side mold 3 and the core side mold 4 of the injection mold 1, the molten resin is injected and integrated.
[0026]
Examples of the resin film used in this production method include polyethylene terephthalate, polyurethane, polyamide, polycarbonate, and films made of these alloys.
[0027]
As this resin film, it is preferable to use a preform 10 that has been preformed into a final product shape in advance. This is because it is not necessary to heat the molten resin at the time of injection and to stretch and deform the resin film at the time of injection and to prevent molding defects due to deformation of the resin film. The preforming process may be performed by a molding method such as vacuum forming or pressure air vacuum forming that is usually used for forming irregularities on the resin film.
[0028]
On the other hand, the filling resin 2 has fluidity suitable for injection molding in a molten state, such as polyurethane, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyacrylonitrile butadiene styrene, and the like. It is desirable to use a resin having solubility.
[0029]
Therefore, first, a temperature adjusting means (not shown) is used for the injection mold 1 to adjust the temperature to be suitable for injection molding.
[0030]
The temperature of the injection mold 1 may be set to a temperature at which the fluidity of the molten resin can be ensured as a whole. However, when the preform 10 is used, the cavity side mold 3 having the recesses 3a is used as the heat of the resin film. It is preferable to set it below the deformation temperature. This is because it is preformed into the final product shape in advance, so that it is not necessary to stretch and deform the resin film at the time of injection, and it is not necessary to heat the resin film excessively.
[0031]
When using the above as the filling resin and the resin film, for example, the temperature of the cavity side mold 3 is preferably set to 40 ° C. or more and less than 80 ° C., more preferably 50 ° C. or more and 60 ° C. or less.
[0032]
On the other hand, the core side mold part 4 may be set to a temperature at which the fluidity of the molten resin can be ensured, like a conventionally used injection mold, like a push button sheet of a mobile phone. When the protruding portion 21 is small, the temperature can be set to the same temperature as that of the cavity side mold 3. When the core side mold part 4 is set to the same temperature as the cavity side mold 3, the gate bush 8 may be set to a temperature at which the fluidity of the molten resin can be ensured.
[0033]
When using the above filling resin and resin film, for example, the temperature of the core side mold 4 is 90 ° C. or higher, more preferably 100 to 120 ° C., and the temperature of the cavity side mold 3 is preferably 40 ° C. or higher and 80 ° C. It is possible to set the temperature below 50 ° C., more preferably 50 ° C. or more and 60 ° C. or less.
[0034]
The temperature of such an injection mold 1 is preferably set before injection molding and kept constant during and after injection molding.
[0035]
Next, as shown in FIG. 3, the injection mold 1 having the temperature set in this way is opened by a parting line between the cavity side mold 3 and the core side mold 4, and the final mold is formed in advance. A plurality of projecting portions of the preform molded body 10 formed into a product shape are inserted into a plurality of concave portions 3 a of the cavity side mold 3 and set. At this time, since the preform molded body 10 is molded into a final product shape, the preform molded body 10 is disposed along the wall surface 3c of the recess 3a.
[0036]
The preform molded body 10 is clamped in a state in which it is set in the cavity side mold 3, and the preform molded body 10 is formed on the surface of the convex portion 6 a of the stripper plate 6 and the opening peripheral edge portion 3 e of the concave portion 3 a of the cavity side mold 3. Between the preform molded body 10 and the recess 3a.
[0037]
Thereafter, molten resin is supplied to the injection mold 1 from a nozzle of a resin supply unit (not shown), and the molten resin is injected into the concave portion 3a of the cavity side mold 3 through the spool portion 8a and the gate portion 8b in the gate bush 8. . When the injection pressure and heat of the molten resin are applied to one side of the preform 10, the other side is brought into close contact with the outer surface 3 b of the recess 3 a of the cavity-side mold 3 and provided on the wall surface 3 c of the recess 3 a. An outer surface that completely matches even a slight unevenness of the display portion or the like is formed.
[0038]
At the time of this injection molding, the recess 3a is sealed between the cavity side mold 3 and the core side mold 4, but the gas in the recess 3a from the gap 13 between the gate bush 8 and the through hole 7 is external. Is discharged.
[0039]
The injection is finished in a state in which the recess 3a is filled with the molten resin, and is solidified to such an extent that the filled resin 2 can be taken out. At this time, the cavity-side mold 3 is set to 40 ° C. or higher and lower than 80 ° C., and the resin film is solidified to such an extent that the outer surface shape can be maintained. Therefore, the filled resin 2 may not be completely solidified. .
[0040]
In order to take out the molded product with film from the injection mold 1, first, the cavity side mold 3 is moved in the mold opening direction with the base plate 5 and the stripper plate 6 being integrated, and the core side mold is moved. Open the mold at the parting line between 4 and 4. As a result, as shown in FIG. 4, the molded product with a film is taken out from the recess 3 a of the cavity side mold 3 in a state where the molten resin in the gate portion 8 b and the filling resin 2 in the recess 3 a are connected.
[0041]
At this time, the gate portion 8b and the end surface 8c of the gate bush 8 and the outer surface 6c facing the recess 3a of the stripper plate 6 are in contact with the filling resin 2 of the molded product with film, and the stripper plate 6 has a convex shape. The part 6a is in contact with the resin film of the molded article with film.
[0042]
Next, when the stripper plate 6 is moved away from the base plate 5 in the mold opening direction, the gate portion 8b and the outer surface 8c of the gate bush 8 and the outer surface 6c and the convex portion 6a of the stripper plate 6 are relatively moved. Leave. Thereby, the filling resin 2 of the molded product with film is pressed by the convex portion 6a of the stripper plate 6 and the resin film of the molded product with film is pressed by the convex portion 6a, as shown in FIG. The product filling resin 2 and the molten resin in the gate portion 8b are separated and cut at the position of the gate portion 8b. As a result, the molded article with a film freely falls from the stripper plate 6 due to the action of gravity and is automatically removed from the injection mold 1.
[0043]
According to such an injection mold 1, the gate bush 8 having the gate portion 8 b in contact with the filling resin 2 in the recess 3 a is locked and integrated at a predetermined position of the base plate 5, and the stripper plate 6 is Since it has an outer surface 6c in contact with the recess 3a and is arranged so as to be movable in the mold opening direction, it is possible to fill the resin for molding with a film by simply moving the stripper plate 6 after the cavity-side mold 3 is opened. Simultaneously with the cutting of the molten resin in the gate portion 8b, the molded product with the film can be removed from the injection mold 1 so that the molded product with the film can be easily taken out.
[0044]
Moreover, since the outer surface 6c of the stripper plate 6 has the convex portion 6a, the resin film can be pressed by the convex portion 6a at the same time that the filling resin 2 of the molded article with film is pressed by the convex portion 6a at the time of removal. The entire molded product with a film can be pressed by the stripper plate 6, and it is difficult to apply a local force, and deformation of the molded product with a film can be prevented at the time of removal.
Moreover, since the convex part 6a of the stripper plate 6 is provided at a position facing the opening peripheral edge part 3e of the concave part 3a, the resin film is sufficiently compressed between the cavity side mold 3 and the convex part 6a. The protrusion 6a and the resin film can be brought into close contact with each other. Therefore, the molten resin does not enter between the convex portion 6a and the resin film at the time of injection, and the filling resin 2 does not adhere to the resin film around the concave portion 3a. Therefore, at the time of removal, the resin film can be pressed in a state where the convex portion 6a is in direct contact with the resin film around the concave portion 3a, the force for pressing the filling resin 2 with the convex portion 6a, and the resin film around the concave portion 3a. Can be made equal to the force with which the protrusion 6a is pressed, and the deformation of the product can be reliably prevented.
[0045]
Further, since the annular convex portion 6a is provided continuously to the stripper plate 6 corresponding to the entire circumference of the concave portion 3a, the convex portion 6a can be in close contact with the resin film all around the concave portion 3a. It is possible to completely and uniformly press the surrounding resin film, and to more reliably prevent the product from being deformed.
[0046]
Moreover, in the said embodiment, although the pillar part which provided the gate part 8b was provided as the gate bush 8, and the cylindrical body 11 of the separate member integrated by being latched to the base plate 5 was demonstrated, The pillar part integrally formed in the column shape may be sufficient. Further, the protruding amount of the column part can be changed as appropriate, and the entire column part may be accommodated in the through hole 7, and when the stripper plate 6 moves to the core side mold 3 side, the through hole extends from the column part. If 7 does not come off, a part of the pillar portion may be accommodated. Further, the gate portion 8 b may be provided directly on the surface of the base plate 5 without providing the pillar portion on the base plate 5. In this case, since the gate portion 8b needs to be in contact with the filling resin 2, a through hole, an opening, or the like is provided at a position corresponding to the gate portion 8b of the stripper plate 6. When the column part is appropriately selected in this way, the relative position of the gate part 8b and the stripper plate 6 in the mold opening direction can be adjusted, and the position of the gate part 8b is set according to the shape of various molded articles with a film. can do.
[0047]
Moreover, although the example which manufactures the pushbutton sheet | seat of a mobile telephone was demonstrated, it may be manufacture of other molded articles with a film, and is applied to the metal mold | die which shape | molds the molded article with a film which has the at least 1 protrusion part 21. It is also possible to do.
[0048]
Furthermore, the surface shape of the convex portion 6a for sandwiching the resin film is also obtained by roughening a part of the surface in contact with the resin film to provide fine irregularities 6d as shown in FIG. 6, for example. It is possible to make appropriate changes, such as making it possible to more securely hold the.
[0049]
【The invention's effect】
As described above, according to the invention described in claim 1, the core-side mold includes the base plate in which the gate portion for injecting the molten resin is integrated, and the concave portion of the base plate and is arranged in the mold opening direction. It has a movable stripper plate, and after opening the mold by pulling the core side mold away from the cavity side mold, the stripper plate is moved to the concave side so that it can be separated from the base plate. And the filling resin can be pulled apart and cut. Therefore, the molded article with a film can be automatically removed simply by moving the cavity side mold and the stripper plate, and the removal is easy.
[0050]
According to the invention described in claim 2 or 3, since the stripper plate has the convex portion opposed to the opening peripheral edge portion of the concave portion, when the gate is cut, the filling resin is applied to the outer surface of the stripper plate. Since the resin film can be pressed with the convex portion at the same time as pressing with the above, in addition to the effect of claim 1, it is possible to press and take out the entire molded product with film. Therefore, it is possible to prevent deformation of the molded product without locally pressing the molded product at the time of taking out.
[0051]
Moreover, even if the thickness of the resin film is not uniform, the resin film can be sufficiently compressed and sandwiched between the convex portions, and the support portion and the resin film can be brought into close contact with each other. Therefore, the molten resin does not enter between the support portion and the resin film at the time of injection, and the filling resin does not adhere to the resin film around the recess. Therefore, the resin film can be pressed in a state where the convex portion is in direct contact with the resin film around the concave portion, the force for pressing the filling resin with the mold surface, and the force for pressing the resin film around the concave portion with the support portion Can be made uniform, and deformation of the product can be surely prevented.
[0052]
According to the invention of the manufacturing method of claim 4, the core-side mold is moved in the mold opening direction by being arranged on the concave side of the base plate with the base plate in which the gate portion for injecting the molten resin is integrated. A stripper plate capable of injecting molten resin from the gate portion to form a molded product with a film into a final product shape, and a step of separating the core side mold from the cavity side mold and opening the mold, Since the gate part is cut by moving the stripper plate to the concave part side and being separated from the base plate to remove the molded product with film from the core side mold, the molten resin and the filling resin in the gate part are separated and cut. Can do. Therefore, the molded article with a film can be automatically removed simply by moving the cavity side mold and the stripper plate, and the removal is easy.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an injection mold used in a manufacturing method according to an embodiment of the present invention.
2 is an enlarged cross-sectional view of the vicinity of a gate bush of the injection mold shown in FIG.
3 is a cross-sectional view showing a state where a preform molded body is arranged in the injection mold shown in FIG. 1. FIG.
4 is a cross-sectional view showing a state where a cavity side mold of the injection mold of FIG. 1 after molding is opened.
5 is a cross-sectional view showing a state in which a stripper plate of the injection mold of FIG. 1 after molding is opened.
FIG. 6 is a cross-sectional view showing a surface shape of a convex portion provided in a core side mold according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view of a conventional molded article with a film having a plurality of protrusions.
FIG. 8 is a cross-sectional view illustrating a process for producing a molded article with a film using a conventional injection mold.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Injection mold 2 Filling resin 3 Cavity side mold 3a Concavity 4 Core side mold 5 Base plate 6 Stripper plate 6a Convex part 6c Outer surface 6d Concavity and convexity 8 Gate bush 8a Spool part 8b Gate part 10 Preform molding 11 Cylinder

Claims (3)

A resin film is disposed between a pair of molds including a cavity-side mold having two or more recessed portions of the final product shape and a core-side mold that closes the recessed portions, and the resin film is injected by injecting a molten resin. An injection mold for a molded article with a film that integrates the molten resin and the resin film while closely contacting the wall surface of the recess,
The core side mold includes a base plate in which a gate portion for injecting the molten resin corresponding to the two or more concave portions is integrated, and a stripper plate that is disposed on the concave portion side of the base plate and is movable in the mold opening direction. And
The stripper plate has an annular continuous convex portion facing each opening peripheral edge of the two or more concave portions, and the convex portion has a width from the inside to the outside of the opening peripheral edge , A part of the convex part and the opening peripheral edge part are provided so as to abut in an annular shape when the mold is closed .
After the core side mold is separated from the cavity side mold and the mold is opened, the stripper plate is moved to the concave side to be separated from the base plate. Mold. The height of the convex part is 20% to 70% of the thickness of the resin film, and the width of the part where the part of the convex part and the peripheral edge of the opening abut in an annular shape is 2 mm or less. The injection mold for a molded article with a film according to claim 1 , wherein the mold is provided on the mold. Use the mold according to claim 1 or 2 ,
The resin film molded body that has been previously molded into the final product shape is inserted into a cavity-side mold having a concave portion of the final product shape, and the mold is closed ,
Injecting the molten resin from the gate portion , and integrating the molten resin and the resin film ;
Separating the core-side mold from the cavity-side mold and opening the mold; and sliding the stripper plate to the concave side and pulling it away from the base plate to cut the gate portion to form the film-molded article. Removing from the core mold,
The manufacturing method of the molded article with a film characterized by having.

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