JP2010264669A - Injection molding method and mold apparatus for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To laminate a film without tearing in the same steps as a resin injection molding when laminating the film on a resin molding component. <P>SOLUTION: After bringing a cavity insert 202 provided on a cavity plate 203 into contact with the film 201 by projecting it toward a core plate direction than a parting surface of the cavity plate 203 and a core plate 209, the film 201 is extended and premolded, the cavity insert 202 is heated with a heater 207, and the film 201 is softened to be easily extended, and furthermore air-sucked. In such a state, the film 201 is molded while firmly attaching to the cavity insert 202. Thus, the injection molding is carried out for laminating the film 201 to the molding component without tearing the film. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an injection molding method and an injection molding die apparatus in which a film is bonded to the surface of an injection molded product at the same time as injection molding when injection molding is performed using a mold. .

  When decorating the surface of a resin part obtained by injection molding, it is common to perform color and patterning by painting. However, due to the diversification of design and environmental problems due to painting, a decoration method that replaces painting is required.

  Therefore, in recent years, a method of attaching a film on which a design is printed to a resin part has attracted attention. Since these films are decorated by printing, it is possible to express designs that cannot be achieved by conventional painting, such as woodgrain or marble. Further, by providing irregularities on the surface of the film, it is possible to express a feeling of touch such as wood grain.

  As a method of laminating these films to resin molded parts, pre-mold a single film using a vacuum molding method or the like into the same shape as the resin molded parts to be laminated with the film, and then place the film in an injection mold. A method is adopted in which the film is inserted into the film, injection molded together with the film, and the film and the resin are bonded by thermal welding.

  However, since the method requires a step of preforming a film, in recent years, efforts have been made to attach a film to the surface of a molded product simultaneously with injection molding in an injection mold.

  Hereinafter, conventional embodiments will be described with reference to the drawings.

  FIG. 10 is a cross-sectional view of a mold employed in a method of simultaneously performing injection molding and film bonding in an injection mold.

  A film 101 to be bonded to a molded resin part is inserted between a cavity plate 102 and a core plate 104 which are provided on a base plate 103 and constitute a mold. Thereafter, the mold is closed, the cavity plate 102 and the core plate 104 are brought into contact, and the resin is poured from the resin insertion port 105 to mold the resin. At the same time, the film 101 is pressed against the surface of the cavity plate 102 by the resin poured from the resin insertion port 105 on the core plate 104 side, and the film is bonded to the molding resin by heat welding.

  However, since the film 101 is formed in a short time of several seconds at the same time as forming with the high-temperature resin pressure poured, the film 101 cannot be fully stretched. In addition, the peripheral film portion that becomes the molded product is sandwiched between the cavity plate 102 and the core plate 104, and the film 101 on the outer peripheral portion does not move in the direction of the molded product as the film 101 is molded. Occurs. This occurrence is particularly conspicuous in a corner portion or a curved surface portion of a resin molded product.

  Therefore, as shown in FIG. 11, an air suction hole 106 penetrating the cavity plate 102 and the base plate 103 is provided, and the film 101 is disposed between the cavity plate 102 and the core plate 103, and then shown in FIG. As described above, there is a configuration in which the film 101 is brought into close contact with the cavity plate 102 by sucking air from the air suction hole 106 so that the film 101 is preformed before injection molding.

  By doing so, the film 101 can be preformed in a shape to be bonded before injection molding, so that the film 101 is less torn compared to the case where the film 101 is molded simultaneously with the injection molding, and the resin 101 Since it becomes easy to adhere, bonding strength also becomes strong (refer to patent documents 1).

JP 2008-105415 A

  However, some problems occur even in the method of preforming the film 101 by sucking air from the air suction holes 106 as shown in FIGS. 11 and 12A.

  First, when air is sucked from the air suction hole 106 and the film 101 is brought into close contact with the cavity plate 102, the deformed portion 108 is formed on the film 101 along the shape of the air suction hole 106 as shown in FIG. Occurs. If the hole diameter of the air suction hole 106 is less than half of the thickness of the film 101, no significant deformation occurs.

  However, since the thickness of the film is generally 0.1 mm to 0.3 mm, it is difficult to process the air suction hole 106 into a hole having a diameter less than half of that. Further, even if the deformation does not occur, the impression of the air suction hole 106 is generated. In particular, it occurs remarkably when the film is in a mirror state.

  Considering the workability of the air suction holes, it is conceivable to use a thick film, but as the film becomes thicker, the moldability of the film becomes worse. In order to improve the moldability of the film, in order to bring the film into close contact with the cavity plate surface, the greater the number of air suction holes, the better the adhesiveness. However, the processing of the air absorption holes becomes more difficult. If the resin molded product is large, many air suction holes are required.

  When the film is preformed with air, as shown in FIG. 12, it is difficult to bring the film 101 into close contact with the corner 107 surface of the cavity plate 102. Since the repulsive force of the film 101 is stronger than the force of bringing the film 101 into close contact with the cavity plate 102 by air, the film cannot be completely stretched, and the film floating at the corner portion 107 occurs. . Further, the adhesion force of the film 101 in the air suction direction is considerably large, but the adhesion force in the direction perpendicular to the suction direction (side wall surface) is weakened.

  When the film 101 is sucked with air, the film 101 needs to be in close contact with the surface of the cavity plate 102. If the float is generated even a little, air leaks from it and the film 101 cannot be formed.

  In order to bring the film 101 into close contact with the surface of the cavity plate 102, it is possible to provide a film retainer 109 on the mold as shown in FIG. However, in this case, since the outer periphery of the resin molded portion of the film is constrained, the film 101 does not move in the direction of the resin molded product at the same time as the air is sucked.

  A film having poor elongation characteristics needs to be moved from the outer periphery during film formation. However, if the film is moved from the outer periphery of the resin molded product toward the center of the resin molded product, the films gather in the central direction, and thus wrinkles are generated in the outer peripheral portion of the resin molded product.

  FIG. 14 shows a partial cross-sectional view of a resin molded product when the film is preliminarily molded by air suction by the above method and then injection molded and the film is bonded. Although the film 101 is pasted on the surface of the resin 111, the film corner portion 110 is torn and the portion 107 that has been sucked in air is deformed as shown in 107.

  After all, with the conventional method of sucking air, it is difficult to preform the film into a predetermined shape without deforming the film.

  The present invention solves the above-described conventional problems, and when performing injection molding and film bonding simultaneously in an injection mold, the film can be preformed without tearing, and the molding resin An object of the present invention is to provide an injection molding method and an injection mold apparatus capable of bonding a part and a film to each other without causing the film to break by bringing the part and the film into close contact with each other.

  In order to achieve the above object, the injection molding method of the present invention supplies a film between a cavity-side mold that is the front side of a molded product and a core-side mold that is the back side of the molded product, and the cavity-side mold While nesting provided in either the mold or the core side mold is moved in the direction of the parting surface that is the mating surface of the cavity side mold and the core side mold, and further while heating the nesting The film is stretched by adsorbing the film and moving the insert, and then retracting the insert to form a cavity where the molded film is present, and injecting resin onto the film surface of the cavity By doing so, a molded product in which the film is bonded is formed.

  Further, the injection mold apparatus of the present invention includes a cavity side mold that is a front side of a molded product, a core side mold that is a back side of the molded product, and any of the cavity side mold and the core side mold. Between the cavity side mold and the core side mold, and a nesting provided on either side and movable in a direction of a parting surface that is a mating surface between the cavity side mold and the core side mold. A film supply unit that supplies the film; a heating unit that is provided in the nest and heats the film; and an adsorption unit that is provided in the nest and adsorbs the film. Supplying a film between the mold and the core side mold, moving the insert in the direction of the parting surface, further adsorbing the film while heating the insert, and moving the insert Forming a cavity in which the film is formed by extending the film and then retracting the insert, and then injecting a resin onto the film surface of the cavity to form a molded product in which the film is bonded It is characterized by doing.

  According to the present invention having the above-described configuration, the nest is protruded from the mating surface (parting surface) of the cavity-side mold and the core-side mold and is brought into contact with the film. At that time, by heating the insert with a heater or the like, the film can be softened and easily stretched. Furthermore, it is possible to perform molding while bringing the film into close contact with the insert by air suction or the like.

  According to the present invention, the nest is projected beyond the mating surface (parting surface) of the cavity side mold and the core side mold, and the film is preformed by the nest. As a result, the film is pre-stretched at the convex part of the nesting, so that even if the film is torn only by the resin pressure at the time of injection molding, the film can be preliminarily produced without tearing. Can be molded.

  Furthermore, the film is easily stretched by heating the nest with a heater or the like to soften the film, and the film can be preformed without tearing the film.

  Further, since the film can be brought into close contact with the nest by air suction or the like, the nest and the film can be reliably molded without being displaced.

  In this way, by pre-molding the film, and then performing injection molding together with the pre-formed film by pouring the resin, there is no film tearing, and the resin-molded product with film in which the film and the resin molded product are in close contact with each other. Obtainable.

Sectional drawing which shows the state of the metal mold | die before film preforming and injection molding in embodiment of this invention Sectional drawing which shows the state of the metal mold | die with which the cavity nest | insert and the film contacted in this embodiment Sectional drawing which shows the state of the metal mold | die which preformed the film in this embodiment Sectional drawing which looked at the state which preformed the film in this embodiment from the film feed direction The top view which showed arrangement | positioning of the film and presser plate in this embodiment Sectional drawing which shows the state of the metal mold | die before the injection molding in this embodiment Sectional drawing which shows the state of the metal mold | die after the injection molding in this embodiment Sectional drawing which shows the state of the metal mold | die which cut | disconnected the film in this embodiment Sectional drawing which shows the state of a metal mold | die when a series of processes in this embodiment are finished and taking out a resin molded part Cross-sectional view of a mold that attaches a film simultaneously with conventional injection molding Sectional view of a mold that preforms a film by conventional air suction Sectional drawing which shows the state of the metal mold | die which preformed the film by the conventional air suction Sectional drawing which shows the state of the metal mold which pressed the film with the conventional film presser Sectional view of a molded resin part with a conventional film tear

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of an injection mold apparatus for attaching a film to the surface of an injection molded product simultaneously with injection molding when a resin molded part is manufactured in the embodiment of the present invention. Indicates the state.

  In FIG. 1, 201 is a film, 202 is a cavity insert made of a porous material, 202a is an air suction hole provided through the cavity insert 202, 203 is a cavity plate, 204 is a plate that supports the cavity plate 203, 205 Is a receiving pin, 206 is a moving pin connected to the cavity nest 202, 207 is a heater provided in the cavity nest 202, 208 penetrates the cavity plate 203 and the plate 204, and the cavity nest 202 and the cavity plate 203 Air suction holes communicating therewith, 209 is a core plate, 210 is a presser plate, 211 is a plate that supports the core plate 209, and 212 is a spring that biases a pin 213 that elastically contacts the receiving pin 205.

  In the present embodiment, the mold is mainly composed of a cavity plate 203 and a plate 204, and is a cavity side mold that is a front side (design surface side) of a molded resin product, and mainly a core plate 209 and a plate 211. It is divided into core mold parts that are configured and become the back side of resin products. When the cavity side mold and the core side mold are open, the film 201 to be attached to the surface of the molded resin component is inserted between the cavity side mold and the core side mold.

  As a method of inserting the film 201, as shown in FIG. 1, a method of automatically feeding the roll material of the film 201 intermittently for each molding shot from the film feeding direction to the winding direction by a conveying means (not shown), or A method of manually attaching the film 201 cut into a shape larger than the size to be attached to the resin molded product to the mold is also possible.

  The next step is shown in FIG. The moving pin 206 is driven to cause the cavity nest 202 to protrude toward the core mold side from the position of the mating surface (parting surface) 214 between the cavity plate 203 and the core plate 209, so that the surface of the cavity nest 202 is the film. It is made to contact 201.

  The cavity insert 202 is heated by the heater 207, and the temperature of the cavity insert 202 is raised, thereby heating the film 201. Note that not only the heater 207 but also hot water, high-temperature fluid, high-temperature steam, or the like may be moved through the hole formed in the cavity nest 202 to raise the temperature of the cavity nest 202.

  By heating the film 201 with the cavity insert 202, the film 201 is softened, and the film 201 is easily stretched and easily deformed. As the heating temperature of the film 201 at this time, it is desirable to set it near the glass transition temperature where the softening of the resin starts. About 100 ° C. is appropriate if the film 201 is ABS-based, and about 120 ° C. is appropriate if the acrylic is acrylic. It is.

  Further, the heating time of the film 201 is appropriately about several tens of seconds to 1 minute, although it depends on the thickness of the film 201. If the thickness of the film 201 is thin, it can be done in a short time, and if it is thick, it needs to be longer. However, care should be taken because the molding cycle becomes longer when heated for a long time.

  Further, at this time, the film 201 can be brought into close contact with the cavity insert 202 by sucking air from the air suction hole 202 a of the cavity insert 202 through the through hole 208. When the film 201 is in close contact with the cavity insert 202, the heat of the cavity insert 202 is reliably transmitted to the film 201.

  In this case, if the air suction hole 202a of the cavity insert 202 has a diameter that is half or more of the film thickness, the film 201 is deformed following the air suction hole 202a.

  However, in the case of a mirror-finished film, even if the diameter is less than half of the film thickness, hole marks remain in the film, so it is necessary to make the diameter 0.1 mm or less. However, it is difficult to drill a hole having a diameter of 0.1 mm, and it is not practical in terms of cost and time to process a large number of holes.

  In the present embodiment, since the film 201 and the cavity insert 202 are partially adsorbed by the air suction holes 202a formed in a limited number of places, the adhesion is weak. Therefore, in addition to forming the air suction holes 202a in the cavity insert 202, it is conceivable to form the cavity insert 202 from a porous material in which countless fine holes are included in the metal material. By doing so, since holes of several tens of microns are vacant inside the metal, air can be passed through, and since the hole diameter is small, there is almost no influence on the film. Depending on the situation, a porous material may be used only for a necessary portion instead of using a porous material for the entire nesting.

  In this way, by using the porous material for the cavity insert 202 and sucking air, the cavity insert 202 and the film 201 are in close contact as a surface rather than in close contact with each other. The gap between the cavity insert 202 and the film 201 can be prevented.

  Next, as shown in FIG. 3, the cavity side mold and the core side mold are closed until the film 201 is sandwiched between the holding plate 210 and the receiving pin 205, and the cavity insert 202, the holding plate 210 and the receiving pin 205 are used. A film 201 is formed. At this time, since the film 201 is pushed up by the cavity insert 202 and the film 201 is formed by the convex portion of the cavity insert 202, the film can be stretched even at a film corner portion that has been difficult in the past.

  In the conventional film preforming method as shown in FIG. 12 (sucking and bringing the film into close contact with the mold surface), the film 101 is not in close contact with the mold at the corner portion 107, and the mold and the film 101 are in contact with each other. Space is generated. Therefore, wrinkles are generated in the film 101, and the film 101 and the mold are misaligned, which causes damage to the film 101.

  On the other hand, in the present embodiment, since the film 201 is formed by the cavity insert 202, the film 201 can be reliably stretched in a place where the corner portion 215 is formed. Furthermore, since the cavity insert 202 is heated and the film 201 is at the glass transition temperature and is in a state of being softened and stretched easily, the film 201 is formed without being broken. Further, since the film 201 is in close contact with the cavity nest 202 by air adsorption, surface displacement does not occur during molding, and wrinkles and scratches of the film 201 can be prevented.

  At this time, the press plate 210 has a gap of 0.05 to 0.5 mm with respect to the film 201. If the film 201 is pressed by the holding plate 210 and the film 201 is prevented from being brought to the center during film formation, the film 201 may be broken.

  Further, if a large gap is left between the presser plate 210 and the film 201, when the film 201 is moved toward the center, it becomes a wrinkle and causes a tear or a poor appearance. As a method of appropriately setting the gap between the presser plate 210 and the film 201, it is conceivable to provide a protrusion 216 on the presser plate 210 as shown in FIG.

  4 is a cross-sectional view of the mold viewed from the film feeding direction, and FIG. 5 is a plan view showing the relationship between the presser plate 210 and the film 201.

  4 and 5, the presser plate 210 is formed into a square ring as a whole, the outer periphery of the resin molded part is constrained in a state of providing a gap with the film 201, and the protrusion 216 for securing the gap is pressed. The plate 210 is installed outside the width of the film 201. The protrusion 216 is brought into contact with the pin 205 so that a gap between the press plate 210 and the film 201 can be secured.

  By performing an operation as shown in FIGS. 3 to 5, the film 201 can be stretched without being torn, and the film can be formed in a state where no wrinkle is generated.

  Thereafter, as shown in FIG. 6, the mold is closed until the cavity plate 203 and the core plate 209 come into contact with each other, and simultaneously with the operation, the moving pin 206 is moved to connect the cavity insert 202 to the cavity plate 203 and the core plate 209. It is made to recede from the parting surface 214. At this time, since air is sucked from the through hole 208, the film 201 is in close contact with the cavity nest 202 by the suction action from the air suction hole 202a formed in the cavity nest 202, and the cavity nest 202 is retracted. Along with the operation, the film 201 is formed into a normal state to be bonded to the resin to be formed.

  Since the film 201 is formed in close contact with the cavity insert 202 in this manner, the film 201 is formed without being displaced, and generation of wrinkles and scratches can be prevented.

  Further, in the step shown in FIG. 3, the film corner portion is already stretched at the convex portion of the cavity insert 202, so that the film corner portion 215 portion in the step of FIG. Close contact. At this time, air is sucked through the air suction hole 202a of the cavity nest 202. However, as described above, the cavity nest 202 may be formed of a porous material. When this process is finished, the film 201 is formed into a shape to be bonded to the resin molded part.

  Next, as shown in FIG. 7, the resin 217 is poured into the gap between the film 201 bonded to the cavity insert 202 and the core plate 209 and injection molding is performed to mold the resin component. Since the film 201 is in close contact with the cavity insert 202 before the injection molding, the film 201 is not broken by the resin pressure of the injection molding. At the same time as the injection molding is performed, the resin 217 and the film 201 are thermally welded, and the film 201 is bonded to the resin 217.

  The next step is shown in FIG. After the injection molding is completed and the injection molded resin part is cooled and solidified, the receiving pin 205 moves. Since the receiving pin 205 and the presser plate 210 are in contact with each other, the presser plate 210 protrudes toward the cavity side mold by the spring 212 at the same time as the receiving pin 205 moves. At that time, the edge portion of the cavity plate 203 and the edge portion of the holding plate 210 are fitted, and the film 201 is cut by a cutting portion provided on the outer shape of the holding plate 210.

  After that, as shown in FIG. 9, when the cavity side mold and the core side mold are opened, the film 201 has already been cut, and thus the resin molded component 218 to which the film 201 is attached is taken out. Since the film 201 is cut by the presser plate 210 and the size thereof is smaller than the material width of the film 201, both end surfaces in the width direction are connected as the roll material of the film 201, and the resin product portion is removed. It becomes a state.

  Therefore, since the roll material of the film 201 can be wound up for one step when the resin injection molding is completed, a new film can be fed between the cavity side mold and the core side mold. Thus, a series of these operations can be performed.

  In this embodiment, the cavity insert 202 is provided in the cavity side mold and the cavity insert 202 is moved. However, depending on the product shape, the core insert is provided in the core side mold, and the core side mold is movable. It is also possible to make it.

  By using the present invention, even a molded resin part having a complicated shape can be bonded to the molded resin part without tearing the decorative film. Conventionally, the film was preformed in a separate process, and then the film was bonded by injection molding.In the present invention, the film is preformed in the same process as the injection molding, and then injection molding is performed. The process can be shortened. As a result, a decorative film is bonded and a molded resin part having a complicated shape can be provided at a low cost, so that it can be applied to a wide variety of injection molding.

201 Film 202 Cavity Nest 202a Air Suction Hole 203 Cavity Plate 204 Plate 205 Receiving Pin 206 Moving Pin 207 Heater 208 Through Hole 209 Core Plate 210 Pressing Plate 211 Plate 212 Spring 213 Pin 214 Parting Surface 215 Film Corner 216 Protrusion 217 Resin 218 Resin parts

Claims (14)

  A film is supplied between the cavity side mold that is the front side of the molded product and the core side mold that is the back side of the molded product, and the nesting is provided in one of the cavity side mold and the core side mold Is moved in the direction of the parting surface that is the mating surface between the cavity side mold and the core side mold, and the film is adsorbed while the insert is heated, and the insert is moved. Forming a cavity in which the formed film is present by extending the insert and then retracting the insert, and then injecting a resin onto the film surface of the cavity to form a molded product in which the film is bonded. A featured injection molding method.   2. The injection molding method according to claim 1, wherein the film is preformed before injection molding, and the injection molding is performed after the film is stretched in advance.   The injection molding according to claim 1 or 2, wherein the film is preformed by causing the nest provided in the cavity side mold to protrude from the parting surface toward the core side mold. Method.   The injection molding according to claim 1 or 2, wherein the film is preformed by causing the nest provided in the core side mold to protrude from the parting surface toward the cavity side mold. Method.   The injection molding method according to claim 1, wherein the film is preformed by heating the nest and bringing the nest into contact with the film to soften the film.   The injection molding method according to claim 1, wherein the film is adsorbed to the nest by air suction.   The said film is preformed by applying pressure to the film from the cavity side mold before the injection molding, and bringing the film into close contact with the core side mold. The injection molding method according to any one of claims. The cavity side mold is provided on one of the cavity side mold that is the front side of the molded product, the core side mold that is the back side of the molded product, and the cavity side mold and the core side mold. And a nest that can move in the direction of the parting surface that is a mating surface of the core side mold, a film supply unit that supplies a film between the cavity side mold and the core side mold, and the nest A heating unit that is provided and heats the film; and an adsorption unit that is provided in the nest and adsorbs the film,
The film supply unit supplies a film between the cavity side mold and the core side mold, moves the insert in the direction of the parting surface, and further adsorbs the film while heating the insert, and the insert The film was stretched by moving the film, and then the cavity was formed by retracting the insert, and the film was bonded by injecting resin onto the film surface of the cavity. An injection mold apparatus for molding a molded product.   The nesting provided in the cavity side mold is provided so as to protrude from the parting surface toward the core side mold with respect to the cavity side mold in order to preform the film. Item 9. An injection mold apparatus according to Item 8.   The nest provided in the core side mold is provided so as to be movable from the parting surface toward the cavity side mold with respect to the core side mold in order to preform the film. Item 9. An injection mold apparatus according to Item 8.   The injection mold according to any one of claims 8 to 10, wherein an air suction hole is provided in the nest, and the film is formed while the nest and the film are brought into close contact with each other by suction of the air suction hole. apparatus.   11. The film is formed while at least a part of the insert is formed of a porous material, and air suction is performed in a porous portion so that the insert and the film are in close contact with each other. The injection mold apparatus of any one of Claims.   The said film is equipped with the mechanism which presses the outer periphery of the said film of the part bonded with a resin molded product, ensuring a some clearance gap, when it pre-molds. Injection mold equipment.   The injection mold apparatus according to claim 13, wherein the mechanism for pressing the film is provided with a cutting portion that cuts an outer periphery of the film after the film is bonded by injection molding.

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