JP5546158B2 - In-mold molding die and in-mold molding method - Google Patents

Description

The present invention relates in-mold molding die used for forming the resin molded product while transferring a pattern pattern, and the in-mold molding how.

  In recent years, it has become impossible to maintain the superiority of products in terms of function and cost, and as a result, the number of companies that have launched strategies for enhancing the design capabilities of products has increased rapidly. Among them, products that require high-quality and diversity in design are the current trend, and the response by conventional painting has become a limit.

  Along with that, the in-mold molding method of mounting a film with a pattern printed on a PC or mobile phone in the mold and integrally molding the resin molded product and the pattern formed on the surface has great expectations. Has been.

First, an outline of this in-mold molding will be briefly described.
FIG. 3 is a diagram illustrating the configuration of a general in-mold molded product.
As shown in FIG. 3, when roughly classified, it is classified into two according to the position of the molded product and the film. When the in-mold foil 101 is transferred to the back side of the molded body 102 with respect to the visible direction (FIG. 3A), the in-mold foil 103 may be transferred to the front side of the molded body 104 (FIG. 3B). ). The above case is called back transfer, and the later is called front transfer. In any case, the molding method for transferring the in-mold foil to the molded body is called in-mold molding.

Hereinafter, conventional in-mold molding will be described with reference to FIGS.
FIG. 4 is a process cross-sectional view illustrating a conventional in-mold molding method. FIG. 5 is a cross-sectional view showing a mold structure used in conventional in-mold molding, FIG. 6 is a diagram for explaining the occurrence of wrinkles in conventional in-mold molding, and FIG. 7 is a conventional in-mold molding provided with a digging surface. It is a figure explaining a method.

  In FIG. 4, first, an in-mold transfer foil 203 to which a design pattern 206 is added is fixed to the mold movable side 204 via the foil feeder upper 201 and fixed by the foil feeder lower 202 (FIG. 4). (A)).

Thereafter, after the mold movable side 204 is moved, the mold is closed, and then the molten resin is injection-molded from the molding machine nozzle 207 (FIG. 4B).
Thereafter, the mold is opened and the molded product 205 is taken out (FIG. 4C). At that time, only the pattern pattern 206 of the in-mold transfer foil 203 is transferred to the surface of the molded product 205, and the in-mold transfer foil 203 fixed to the foil feeder upper 201 and the foil feeder lower 202 has no pattern pattern 206. It becomes.

  When the next molding is performed, the top 201 of the foil feeder and the bottom 202 of the foil feeder are rotationally driven, and the in-mold transfer foil 203 to which the design pattern 206 is added is sent to prepare for the next molding.

  In this way, the molding in which the design pattern 206 is transferred to the surface of the molded product 205 is called in-mold molding (see, for example, Patent Document 1).

JP-A-1-241416

  However, there is a problem in quality when the design is transferred using the in-mold foil 302 on the flat surface of the molded product 301 as shown in FIG. The detailed configuration of the contents will be described below.

  For example, when in-mold molding is performed on a molded product 301 having a flat shape, first, an in-mold foil 302 to which a design pattern is added is placed on the mold surface 304 before molding. At that time, the foil retainer 303 is still protruding from the surface of the in-mold foil 302 and does not touch the in-mold foil 302. Therefore, first, the in-mold foil 302 is sucked from the suction groove 305 to bring the in-mold foil 302 into close contact with the mold surface 304, so that the in-mold foil 302 is not displaced. While maintaining this close contact state, the foil retainer 303 is lowered and the in-mold foil 302 is fixed. Only in this state is the molten resin injected through the resin flow path (sprue 306) in the mold. Thereafter, through a cooling step, a molded product 301 made of the above-described resin is formed on the in-mold foil 302, and the molded product 301 is taken out by opening the mold. The pattern added to the in-mold foil 302 is in close contact with the surface of the molded product 301 taken out at that time.

  However, as shown in FIG. 6, when the in-mold foil 401 is sucked from the suction groove 402 via the suction hole 403, the in-mold foil 401 hits the edge portion of the suction groove 402 and no further suction can be performed (FIG. 6). (A)). As a result, air remains between the central portion of the in-mold foil 401 and the mold movable side surface 404, and a wrinkle 405 is generated and resin molding is performed with insufficient adhesion to the mold movable side surface 404. (FIG. 6B). In such a case, there is a problem that sufficient appearance quality cannot be maintained due to the wrinkles 405 generated on the surface of the molded product on the in-mold foil side.

  For this reason, when in-mold foil transfer is performed on the surface of a flat molded product, a digging surface is provided on the mold movable side surface 504 in order to cover instability of adhesion due to suction as shown in FIG. In general, when the resin flows, it is generally attempted to improve the adhesion by utilizing the flow while pressing the in-mold foil 501 against the mold movable side surface 504.

  However, since the in-mold foil 501 wraps around part of the side surface of the molded product (molded product 505 after molding), the in-mold foil 501 adheres to and adheres to at least a part of the side surface of the molded product 505. However, since the side with the in-mold foil 501 and the side without the side are mixed, the appearance is not so good.

  In addition, even if molded by this method, because there is a step between the suction surface and the mold movable side 504, the adhesion between the in-mold foil 501 and the mold movable side 504 becomes non-uniform due to vacuum suction, Since the close contact between the in-mold foil 501 and the mold movable side surface 504 may not be ensured, the adhesiveness may become unstable, and the wrinkle of the in-mold foil 501 still occurs, resulting in poor appearance of the molded product. There was a problem that it occurred.

  In order to solve the above-described problems, an object of the present invention is to suppress the generation of wrinkles in an in-mold foil during in-mold molding.

In order to achieve the above object, an in-mold mold of the present invention is an in-mold mold used for in-mold molding, and a first mold on which an in-mold foil to which a design pattern is added is placed. A second mold provided with a nozzle for injecting resin, a suction groove provided in the first mold for sucking in-mold foil, and a space between the cavity region of the first mold and the suction groove And a plurality of convex shapes that are spaced apart from each other, and a tapered shape that is formed on the side surface of the suction groove that is close to the cavity region .

Further, the convex shape is formed over the entire outer periphery of the cavity region.
Further, the convex shape is formed on a part of the outer periphery of the cavity region.

Further, the convex shape is formed on the long side of the outer periphery of the cavity region.
The convex shape is formed on a short side of the outer periphery of the cavity region.

Further, the convex shape is formed in a region separated from the cavity region by 5 mm to 10 mm.
Further, the height of the convex shape from the surface of the first mold is 10 μm to 50 μm.

Et al is, in-mold molding method of the present invention is an in-mold molding method using the in-mold molding die, the in-mold foil on said convex shape of the first mold is provided surface A step of placing, a step of sucking the in-mold foil from the suction groove to bring the in-mold foil into close contact with the first mold, and a step of attaching the second mold to the first mold through the in-mold foil. It has the process of inject | pouring resin into a cavity from the said nozzle joined to a metal mold | die, and the process of taking out the resin molded product to which the said pattern pattern was transferred, It is characterized by the above-mentioned.

Furthermore, the in-mold molded product of the present invention is characterized by being molded using the in-mold molding die.
Moreover, it shape | molded with the said in-mold shaping | molding method, It is characterized by the above-mentioned.

  As described above, during in-mold molding, the occurrence of wrinkles in the in-mold foil can be suppressed, and the occurrence of defective appearance of the molded product can be suppressed.

  As described above, by providing a convex shape between the cavity region of the in-mold molding die on which the in-mold foil is placed and the suction groove, the in-mold foil can be sufficiently sucked. Generation | occurrence | production of the wrinkle of foil can be suppressed and generation | occurrence | production of the external appearance defect of a molded product can be suppressed.

Sectional drawing which shows the structure of the in-mold mold in this invention The top view which shows the example of arrangement | positioning of the convex shape of this invention The figure explaining the composition of a general in-mold molded product Process sectional drawing explaining the conventional in-mold molding method Sectional drawing showing the mold structure used for conventional in-mold molding The figure explaining the occurrence situation of wrinkles in the conventional in-mold molding The figure explaining the in-mold molding method which provided the conventional digging surface

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 1 is a cross-sectional view showing the configuration of an in-mold molding die according to the present invention, and FIG. 2 is a plan view showing an example of the arrangement of convex shapes according to the present invention.

  As shown in FIG. 1, an in-mold foil 601 is brought into contact with the surface including the cavity surface of the first mold 602, and the first mold 602 and the second mold 606 are clamped to form a resin in the cavity. In the in-mold molding method of injecting and molding a mold, in the present invention, (a) an in-mold foil 601 is provided between a first mold 602 and a second mold 606 having a convex shape 603 around a plane constituting a cavity. (B) Air is sucked from the suction groove 607 provided in the first mold 602 at a position facing the “parting surface” around the cavity surface of the second mold 606 to remove the in-mold foil 601. (C) the first mold 602 and the second mold 606 are clamped together to inject the resin into the cavity formed to mold an in-mold molded product; After opening the mold Take out the molded article.

  According to the present invention, a convex shape 603 that is about 10 μm to 50 μm higher than the parting surface is disposed on the inner periphery of the suction groove 607 that is installed to bring the in-mold foil 601 into close contact with the first mold 602. Features. The above-described convex shape 603 is disposed between a cavity region, which is a region where the molded product 605 on the surface of the first mold 602 is formed, and the suction groove 607, and has an appearance such as wrinkles that are likely to occur in the in-mold foil 601. The above-described convex shape 603 is arranged in a place where defects are likely to occur. Moreover, as the arrangement position of the convex shape 603, it can arrange intermittently in the perimeter or part of a cavity area | region.

The suction groove 607 described above preferably has a tapered shape 604 with an inclined surface formed on the side surface of the groove near the cavity region.
In the molded product obtained by such an in-mold molding method, the in-mold foil 601 is easily sucked, and generation of wrinkles and the like of the in-mold foil 601 is suppressed, and a molded product that does not cause appearance defects is obtained. . Further, the present invention is an in-mold molding method characterized in that the effect appears strongly with respect to the shape of the flat surface of the in-mold foil.

  Here, the generation of wrinkles will be described. As shown in FIG. 6, the in-mold foil 401 is vacuum-sucked from the suction groove 402 and pulled outside to try to adhere to the mold operation side surface 404. However, when the in-mold foil 401 is caught on the edge portion of the suction groove 402, the suction does not function at all thereafter, resulting in poor adhesion between the in-mold foil 401 and the mold operation side surface 404. A gap is created. In the case of molding in that state, the resin flowed over the in-mold foil adhesion failure portion, and the in-mold foil 401 finally generated wrinkles 405 in a crushed state (FIG. 6). (B)).

  In contrast, in the present invention, by providing a convex shape between the cavity region and the suction groove, the suction of the in-mold foil from the suction groove is facilitated, so that the generation of wrinkles in the in-mold foil is suppressed. The appearance defect can be suppressed without leaving the in-mold foil on the surface of the molded product. Furthermore, by forming a taper in the suction groove, it is possible to suppress the catch of the in-mold foil during suction, so that the suction of the in-mold foil becomes easier, so that the generation of wrinkles in the in-mold foil can be suppressed. it can.

Furthermore, it will be as follows when embodiment of a metal mold | die is described in detail.
In order to bring the in-mold foil 601 into close contact with the first mold 602, a convex shape 603 is provided so that a slit is formed in the outer peripheral portion of the cavity region on the surface of the in-mold mold.

  Since the slit-like convex shape 603 exists, the air between the first mold 602 and the in-mold foil 601 is always easily removed from the slit. Therefore, when sucking from the suction groove 607, the adhesion between the in-mold foil 601 and the first mold surface 602 is enhanced, and the effect of suppressing the generation of wrinkles is achieved. As shown in FIG. 1B, which is an AA cross-sectional enlarged view of FIG. 1A, slits are formed in the convex shape 603 in pieces. Thus, even if the in-mold foil 601 is attracted | sucked, the space | gap is completely filled up by forming a space | gap between the adjacent slit-shaped convex shape 603 by arrange | positioning the slit-shaped convex shape 603 in pieces. In this way, the in-mold foil 601 does not go around. That is, a gap is always generated between the first mold 602 and the in-mold foil 601 at the outer periphery of the cavity region. For this reason, even if suction is performed from the suction groove 607, air can surely escape from the gaps described above, the adhesion between the in-mold foil 601 and the first mold surface 602 is improved, and the in-mold foil 601 is further improved. This improves the adhesion.

  Further, in order to improve the adhesion between the in-mold foil 601 and the first mold surface 602, a tapered surface 604 is provided on the side surface of the suction groove 607 on the cavity region side. This is because when the in-mold foil 601 performs vacuum suction through the suction groove 607, the in-mold foil 601 is caught by the edge portion of the suction groove 607, and the suction force is not easily transmitted to the in-mold foil 601. Thus, in order to prevent the adhesion between the in-mold 601 and the first mold surface 602 from decreasing, an inclined surface is formed at the edge portion of the suction groove 607 to form a tapered surface 604. When the in-mold foil 601 is pulled in the direction of the suction groove 607 by the suction force generated from the suction groove 607, the in-mold foil 601 becomes slippery because it becomes slippery, and the in-mold foil 601 is in a properly tensioned state. Stretched. In this way, since the tension of tension is easily applied, the in-mold foil 601 is less likely to be caught in the suction groove 607, so that the adhesion is further improved and the generation of wrinkles in the in-mold foil 601 can be suppressed. Is.

Further, the convex arrangement will be described with reference to FIG.
In a state where the mold is still open before molding, the in-mold foil 706 is installed in a state where it is connected from the foil feeder upper 201 to the foil feeder lower 202 as in the conventional configuration shown in FIG. 701 is laid. On the other hand, a convex shape 705 disposed with a slit-shaped gap is disposed on the outer periphery of the cavity region at a position about 5 mm to 10 mm away from the range of the cavity region where the molded product 703 is formed.

  If the position of the slit-like convex shape 705 is shorter than the range of 5 mm to 10 mm from the cavity region, the tension of the in-mold foil 706 laid on the cavity region is excessively applied, and the in-mold foil 706 is torn. Is not desirable because it may occur.

  Further, if the distance is too long, the vacuum suction force from the suction groove 704 is not easily transmitted to the in-mold foil 706 laid in the cavity region, which causes a decrease in the adhesion force.

  Note that the slit-shaped convex shape 705, in other words, the plurality of convex shapes 705 arranged at regular intervals are integrated with the first mold surface 701 or are formed of divided parts. Both are fine.

FIG. 2A shows a pattern in which a plurality of convex shapes 705 arranged in a slit shape are arranged on the entire circumference. The insert 702 for the product part incorporated in the first mold surface 701 is in the inner peripheral part. A cavity region where the molded product 703 is formed is further inside the insert 702 for the product portion. A slit-like convex shape 705 is disposed in the outer peripheral range of 5 mm to 10 mm of the cavity region where the molded product 703 is formed. The interval between the convex shapes 705 is not particularly specified. This is because the in-mold foil 706 tends to be in close contact between the slit-shaped convex shapes 705, but it is impossible to make close contact with the root, so a gap is always generated. This is because the adhesiveness of the in-mold foil 706 is improved if the gap is very small.

  A suction groove 704 is arranged on the further outer side of the slit-like convex shape 705, and it is desirable that the distance is set so as not to increase the size of the mold. In particular, since it is a dimension that also affects the width of the in-mold foil 706, excessively taking it may affect the material cost of the in-mold foil 706, which is also not desirable.

  FIG. 2A shows the case where the plurality of convex shapes 705 are arranged at predetermined intervals over the entire outer periphery of the cavity region, but the predetermined interval is provided at a part of the outer periphery of the cavity region. A plurality of convex shapes 705 may be arranged.

  FIG. 2B shows the arrangement of the slit-like convex shapes 705 only in the longitudinal direction of the cavity region where the molded product 703 is formed. Similarly, FIG. 2C is arranged only in the short direction of the cavity region. If the shape of the molded product 703 is likely to generate wrinkles in the longitudinal direction, wrinkle generation can be adjusted by intensively arranging slit-like convex shapes 705 in the longitudinal direction.

  Similarly, if wrinkles are likely to occur in the short direction from the range of the molded product 703, wrinkle generation can be adjusted by intensively arranging slit-like convex shapes 705 in the short direction. .

  Here, the wrinkle-prone shape means, for example, a shape having a flat surface only in the longitudinal direction, and in this case, the convex shape 705 is arranged only in the longitudinal direction. The same action is taken for the short direction.

As described above, the slit-like convex shape 705 may be arranged on the entire outer periphery of the molded product 703 or may be arranged in pieces.
In addition, regarding the dimension setting in the height direction of the slit-like convex shape 705, the height is adjusted according to the state of occurrence of wrinkles. However, there is a limit in the thickness direction, and about 10 μm to 50 μm is desirable.

  This is because if it is thicker than that, the parting line surface of the mold will float, which may cause burrs from the range of the molded product 703 during molding. For this reason, it is desirable to adjust the thickness so as not to generate burrs, and it is desirably about 10 μm to 50 μm.

  As a result of the implementation as described above, even when a molded product having a flat shape without a digging surface is formed in-mold, the adhesion between the in-mold foil and the mold surface is increased, and the subsequent resin is injected. Even in the applied state, wrinkles are less likely to occur. In this way, by providing a plurality of convex shapes with a certain interval on the surface of the mold, the generation of wrinkles can be suppressed, and the appearance defect of the molded product can be suppressed.

  Furthermore, the shape like a flat plate was rather difficult to in-mold, but in the future it will be possible to cope with such a shape, and there is a merit that the application range of in-mold molding can be expanded accordingly. come.

  The present invention suppresses the occurrence of wrinkles in an in-mold foil, can suppress the appearance defect of a molded product, and is used when forming a resin molded product while transferring a pattern pattern. It is useful for methods, in-mold molded articles, and the like.

DESCRIPTION OF SYMBOLS 101 In-mold foil 102 Molded body 103 In-mold foil 104 Molded body 201 On foil feeder 202 Under foil feeder 203 In-mold transfer foil 204 Mold movable side 205 Molded article 206 Pattern pattern 207 Molding machine nozzle 301 Molded article 302 In-mold Foil 303 Foil presser 304 Mold surface 305 Suction groove 306 Sprue 401 In-mold foil 402 Suction groove 403 Suction hole 404 Mold movable side surface 405 Wrinkle 501 In-mold foil 504 Mold movable side surface 505 Molded product 601 In-mold foil 602 First mold 603 Convex shape 604 Tapered shape 605 Molded product 606 Second mold 607 Suction groove 701 First mold 702 Nested 703 Molded product 704 Suction groove 705 Convex shape 706 In-mold foil

Claims (8)

An in-mold mold used for in-mold molding,
A first mold on which an in-mold foil to which a design pattern is added is placed;
A second mold provided with a nozzle for injecting resin;
A suction groove provided in the first mold for sucking an in-mold foil;
A plurality of convex shapes arranged spaced apart from each other between the cavity region of the first mold and the suction groove;
An in-mold mold having a tapered shape formed on a side surface of the suction groove close to the cavity region.   The in-mold mold according to claim 1, wherein the convex shape is formed over the entire outer periphery of the cavity region.   The in-mold mold according to claim 1, wherein the convex shape is formed on a part of the outer periphery of the cavity region.   The in-mold mold according to claim 3, wherein the convex shape is formed on the long side of the outer periphery of the cavity region.   The in-mold mold according to claim 3, wherein the convex shape is formed on a short side of the outer periphery of the cavity region.   The in-mold mold according to any one of claims 1 to 5, wherein the convex shape is formed in a region separated from the cavity region by 5 mm to 10 mm.   The in-mold mold according to claim 1, wherein a height of the convex shape from the surface of the first mold is 10 μm to 50 μm. An in-mold molding method using the in-mold mold according to claim 1,
Placing the in-mold foil on the surface of the first mold provided with the convex shape;
Sucking the in-mold foil from the suction groove and bringing the in-mold foil into close contact with the first mold; and
Bonding the second mold to the first mold via the in-mold foil and injecting resin from the nozzle into the cavity;
And a step of taking out a resin molded product to which the design pattern is transferred.

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