JP4118597B2 - Sheet pasting injection compression molding method and molding apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet-attached injection compression molding method and a molding apparatus for manufacturing a resin product in which a sheet having a pattern transferred on its surface is integrally bonded.
[0002]
[Prior art]
In recent years, resin products used for automobile interior parts, home appliances, and the like have been demanded to have high added value with design and functionality by decorating the surface.
In order to mold such a high-value-added resin product, for example, as shown in FIGS. 9 to 12, a fixed mold 51 and a movable mold (porous electric mold) which are a pair of molds opened. 52, a preheated sheet 53 is disposed, the end of the sheet 53 is held and fixed by the clamper 54, and the sheet 53 is placed along the parting surface (see FIG. 9), and then the movable side mold The space S formed by the concave mold surface (mold cavity surface) 52a of the sheet 52 and the sheet 53 is vacuum-sucked to bring the sheet 53 into close contact with the cavity surface 52a, and the sheet 53 is vacuum-formed. The pattern (texture) is transferred to the surface of the sheet 53 (see FIG. 10), and then the resin base 55 is melted between the convex mold surface 51a of the fixed mold 51 and the sheet 53 at a predetermined mold position. Filled with resin 55a 11), the sheet 53 and the molten resin 55a are integrated by clamping and shaping (see FIG. 12), and after the cooling of the molten resin 55a is completed, the mold is opened and taken out from the molds 51 and 52. A resin product in which the sheet 53 is integrally bonded to the resin base material 55 is obtained.
[0003]
[Problems to be solved by the invention]
However, in the conventional resin product molding method and molding apparatus described above, since the end of the sheet 53 is fixed by the clamper 54 when the sheet 53 is vacuum-formed, as shown in FIG. There is a problem that the stretching ratio of the sheet 53 is increased, local extension is unavoidable, and the uneven thickness of the sheet 53 is increased. In particular, in the case of deep drawing or the like, the sheet 53 is deformed to the cavity surface 52a by the elongation of the sheet 53 at the time of vacuum forming, so that the elongation rate of the sheet 53 becomes large and thin, and the necessary cushioning properties (elasticity). In an extreme case, the sheet 53 may be broken.
Further, in the conventional resin product molding method and molding apparatus, since the vacuum molding is performed without closing the molds 51 and 52, the degree of adhesion of the sheet 53 to the cavity surface 52a does not increase, and the transferability is poor. There was a problem. Moreover, since it is necessary to bring the sheet 53 into close contact with the cavity surface 52a in a state where a gap is opened between the parting surface of the fixed mold 51 and the sheet 53, a large suction force is required. There was a risk of increasing the size of the vacuum suction device.
[0004]
The present invention has been made in view of such a situation, and its purpose is to suppress wrinkles on the sheet surface, to prevent local spread and breakage of the sheet, and to improve the sheet product surface from the mold surface. An object of the present invention is to provide a sheet-attached injection compression molding method and a molding apparatus capable of obtaining a resin product having excellent product surface and elasticity by ensuring transferability.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems of the prior art, the present invention provides an end portion between a pair of molds each having a correspondingly shaped concavo-convex portion and having a pattern engraved on the concave mold surface. And placing a preheated sheet while holding the mold movably, and inserting the majority of the sheet into the concave cavity of the other mold by the convex part of the one mold while closing the mold. And vacuum suction of the space formed by the concave mold surface and the product surface of the sheet, and the pair of molds are clamped to the mold alignment position while the vacuum suction is maintained and fully closed. Vacuum forming the sheet, transferring the pattern of the concave mold surface to the product surface of the sheet, opening the pair of molds, and the convex mold surface of the one mold Molten resin in the space formed by the anti-product surface of the sheet In the sheet laminated injection compression molding method and a step of filling by injection compression molding, an end portion of the sheet, when the sheet is drawn into the recess cavity, the retention Ru is released.
Furthermore, in the present invention, it is preferable that the sheet is a laminated sheet composed of an elastomer layer and a foam layer, and the pattern of the concave mold surface is transferred to the elastomer layer.
[0006]
The present invention also includes a pair of openable and closable molds having any one of the correspondingly shaped concavo-convex portions, a pattern is engraved on the concave mold surface, and a vacuum seal member is provided around the concave portion , In order to insert and arrange a preheated sheet between these molds, a holding means for holding the end portion in a movable state, a vacuum suction device for vacuum suction in the cavity of the mold, and the mold An injection device for injecting and filling molten resin into the cavity, and the preheated sheet is placed on the vacuum seal member, and the one of the sheets is held while holding the end of the sheet by the holding means when the mold is closed Most of the sheet is inserted by being shifted into the concave cavity of the other mold at the convex portion of the mold, and the space formed by the concave mold surface and the product surface of the sheet is vacuumed. Vacuum suction with a suction device While holding the suction, the pair of molds are clamped and fully closed to vacuum form the sheet, and the pattern of the concave mold surface is transferred to the product surface of the sheet. The mold is opened, molten resin is injected and filled into the space formed by the convex mold surface of the one mold and the anti-product surface of the sheet, and the sheet and the molten resin are compression molded. It is configured as follows.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a sheet bonding injection compression molding method and a molding apparatus thereof according to the present invention will be described in detail based on the illustrated embodiments. Here, FIG. 1 to FIG. 8 are explanatory views of a sheet-attached injection compression molding method and a molding apparatus for carrying out the method according to the embodiment of the present invention, and FIG. 1 is a conceptual diagram of a stage for preheating the sheet, FIG. Is a conceptual cross-sectional view of a stage in which a preheated sheet is placed between a pair of molds, and FIG. 3 is a conceptual cross-sectional view of a stage in which the sheet is inserted into the recess cavity and vacuum sucked while the mold is closed. 4 is a conceptual cross-sectional view of the stage in which the sheet is vacuum-formed in the fully closed state and the pattern is transferred to the product surface of the sheet. FIG. FIG. 6 is a conceptual cross-sectional view of the stage where the space with the non-product surface is filled, FIG. 6 is a conceptual cross-sectional view of the stage where the mold is clamped and injection compression molded, and FIGS. It is a flowchart until it obtains a resin product with a shaping | molding method.
[0008]
The sheet-attached injection compression molding method and molding apparatus of the present embodiment manufactures a resin product that has been given design and functionality by decorating the surface. Such a resin product is shown in FIG. As shown in FIG. 6, the resin sheet 2 is integrally bonded to the upper part of the resin base material 1. The resin sheet 2 of the present embodiment is a laminated sheet without a wrinkle pattern composed of a thin elastomer layer 3 to be a product surface and a thick sponge-like foam layer 4. In the vacuum forming, it is transferred to the elastomer layer 3 side.
[0009]
Further, in the molding apparatus that performs the sheet-attached injection compression molding method of the present embodiment, a pair of ceramic heaters 5 for heating the resin sheet 2, and the molten resin 1 a and the resin sheet 2 that become the resin base material 1 are injection-compressed. A fixed side mold 6 and a movable side mold 7, a sheet guide (holding means) 8 that holds the end of the resin sheet 2 movably, and the like are used.
The fixed mold 6 is attached to a fixed plate (not shown), and a convex mold surface 6 a is provided on the surface facing the movable mold 7. The movable mold 7 is attached to a movable plate (not shown) so that the mold can be clamped by moving to a desired position together with the movable plate by driving a mold clamping device (not shown). It is configured. And the concave mold surface 7a which comprises a mold cavity surface is provided in the surface facing the fixed mold 6 of the movable mold 7, and the concave mold surface 7a and the resin sheet 2 are formed around the concave section. A vacuum seal member 9 is provided to increase the degree of vacuum in the space formed with the product surface. The convex mold surface 6a and the concave mold surface 7a are formed in concave and convex portions having shapes corresponding to each other, and a concave pattern (decorative pattern) transferred to the product surface of the resin sheet 2 is engraved on the concave mold surface 7a. It is installed.
[0010]
On the other hand, the sheet guide 8 grips the end of the sheet when the resin sheet 2 is supplied to the molds 6 and 7 (fixed for initial positioning), and releases the grip of the end of the sheet when pulled into the concave mold surface 7a. It is composed of a clamper or the like that can be used. That is, the end of the resin sheet 2 is set so that the holding is released when the resin sheet 2 is drawn into the concave cavity. However, the end portion of the resin sheet 2 may be stabbed with a pin or the like for initial positioning, and when the resin sheet 2 is drawn into the concave mold surface 7a, the end portion of the sheet may be partially broken by the drawing force.
[0011]
The mold cavity formed by the fixed side mold 6 and the movable side mold 7 communicates with an injection device (not shown) that injects and fills the molten resin 1a to be the resin base material 1. The movable mold 7 is connected to a vacuum suction device (not shown) having an open / close valve, a vacuum chamber, a vacuum pump, and the like, and the inside of the vacuum chamber is maintained at a pressure of −740 to −720 torr. Is set to be. Therefore, the inside of the mold cavity is configured to be vacuum-sucked by a vacuum suction device (not shown) as indicated by an arrow in FIG.
[0012]
Next, a procedure for manufacturing a resin product using the sheet-attached injection compression molding method and molding apparatus according to the embodiment of the present invention will be described.
First, in the preliminary heating stage of the resin sheet 2 as the first step, as shown in FIG. 1, the resin sheet 2 is disposed between the ceramic heaters 5 and the set temperature of the ceramic heater 5 is set to about 230 ° C. In this state, the resin sheet 2 is placed for about 60 seconds and heated until the temperature of the product surface reaches about 200 ° C. in order to ensure the transferability of the concave pattern surface 7a to the elastomer layer 3.
Then, at the stage where the preheated resin sheet 2 is placed between the fixed mold 6 and the movable mold 7 in the mold open state, as shown in FIG. While being movably held, it is inserted between the fixed mold 6 and the movable mold 7 and installed on the parting surface of the movable mold 7 provided with the vacuum seal member 9. At this time, the fixed mold 6 and the movable mold 7 are heated to a temperature of about 60 ° C. in order to ensure good transferability.
[0013]
Next, at the stage of vacuum suction, as shown in FIG. 3, the movable side mold 7 is moved toward the fixed side mold 6 (in the direction of the arrow in the figure), and the mold is closed. Then, the resin sheet 2 is drawn toward the concave mold surface 7a of the movable mold 7 while being displaced by the convex mold surface 6a of the fixed mold 6, and is inserted (plug pushed) into the concave cavity. Then, with most of the resin sheet 2 inserted into the concave cavity of the movable mold 7, the space S1 formed by the concave mold surface 7a and the resin sheet 2 is vacuum-sucked by a vacuum suction device (not shown). Do. The state in which most of the resin sheet 2 is inserted into the concave cavity substantially corresponds to the case where the relative distance between the opposing surfaces of the fixed mold 6 and the movable mold 7 reaches 50 mm. For example, when this relative distance is detected and reaches 50 mm, vacuum suction may be started.
[0014]
Subsequently, at the stage of vacuum forming, as shown in FIG. 4, the movable mold 7 is further moved toward the fixed mold 6 (in the direction of the arrow in the figure) while maintaining vacuum suction, and these molds are moved. Clamp 6 and 7 to the mold alignment position and fully close. Then, the resin sheet 2 is vacuum-formed by a high vacuum suction force obtained by fully closing the mold, and the surface of the elastomer layer 3 is brought into close contact with the concave mold surface 7a of the movable mold 7, so that the concave mold surface 7a This wrinkle pattern is transferred to the elastomer layer 3 which is the product surface of the resin sheet 2.
[0015]
Next, in the injection compression molding stage, as shown in FIG. 5, the movable side mold 7 is moved to a predetermined position toward the opposite side of the fixed side mold 6 (in the direction of the arrow in the figure), and the mold 6, 7 mold opening is performed. In this state, molten resin 1a is injected into a space S2 formed by the convex mold surface 6a of the fixed mold 6 and the non-product surface (foamed layer 4 side) of the resin sheet 2 by an injection device (not shown). The space S2 is filled with the molten resin 1a. Thereafter, as shown in FIG. 6, the movable mold 7 is moved toward the fixed mold 6 (in the direction of the arrow in the figure), and the molds 6 and 7 are clamped to perform shaping. And the resin sheet 2 and the molten resin 1a are integrated. Therefore, after completion of the cooling of the molten resin 1a, the movable side mold 7 is moved toward the opposite side of the fixed side mold 6 to open the mold. A resin product in which the sheet 2 is integrally bonded to the resin base material 1 is obtained.
[0016]
Further, the sheet pasting injection compression molding method according to the embodiment of the present invention will be described in detail with reference to the flowcharts shown in FIGS. In this molding method, vacuum suction control mode timers TA to TF (if there is at least one) are used in order to perform control to end vacuum suction at a required timing, these timers are set in advance, TA to TF in the figure indicate the start timing of the timer, and since this timing is highly flexible, some examples are shown. In the flowchart, mold opening control modes A to C are set in advance (selection is possible from three or two, or an apparatus capable of only one of them may be used). In the control mode A, the mold opening setting position set in advance during injection is held until the next process (compression) is started. In the control mode B, an arbitrary mold clamping force set in advance during injection is held until the next process (compression) is started. In the control mode C, the pressure inside the mold is set in advance during injection until the process proceeds to the next step (compression).
[0017]
In the start of the molding method of the present embodiment, the preheated sheet is set at a predetermined position between a pair of molds. If the sheet set is defective, start over. When the sheet setting is completed, the mold is closed at an optimum speed so as to reach the set position of the mold. During this time, vacuum suction is started in order to bring the sheet into close contact with the concave mold surface, and when the set time comes, the vacuum suction is terminated. Then, the vacuum suction control mode is disabled (the operation timer is reset). If the set position is not reached, mold closing is repeated.
Next, the mold is placed at the fully closed setting position by closing the mold, the mold closing is held with an arbitrary clamping force, and the preload is held until the set time comes. When the preload holding time comes, the mold is moved to the mold opening set position, the mold is opened, and the mold is stopped. The preload holding is repeated until time elapses, and the mold opening is repeated until the mold reaches the set position.
[0018]
In this state, when the set time elapses, the molten resin is injected into the mold cavity from the standby injection apparatus, and the set amount of molten resin is filled in the set time. On the other hand, simultaneously with the start of injection, the mold position, the mold clamping force, and the mold internal pressure are held in accordance with a mold opening / closing control mode selected in advance. When reaching an arbitrary preset time after the start of injection or an arbitrary preset filling amount (for example, screw position), the mold is closed at a preset mold clamping force or mold moving speed, and compression is started. The compression is continued until the mold reaches the set position or the set time is reached, and then the mold is pressure-clamped with a preset mold clamping force to perform compression. The injection of the molten resin is completed before the mold clamping pressure increase described above is started. When a set time has elapsed after the completion of the injection, the screw of the injection device is rotated to perform plasticization. Then, when plasticization is completed, it waits for the next molding (injection).
Cooling the product sheet and molten resin together with mold clamping pressure, and after cooling, move the mold until it reaches the set time or set position, it becomes possible to take out the resin product, one cycle for molding Ends. Thereafter, molding of the next resin product is started.
[0019]
In the sheet-bonding injection compression molding method and molding apparatus of the embodiment of the present invention, the sheet end is not fixed by a clamp or the like but is held movably by the sheet guide 8. The resin sheet 2 is smoothly drawn and inserted into the concave cavity of the movable mold 7 by the convex mold surface 6 a of the mold 6, and there is almost no local extension of the resin sheet 2. It is possible to obtain a good product surface with less wrinkles and beautifully transferred wrinkle patterns, and even with a thick sheet where cushioning is important, its performance is not impaired, and it is an excellent quality resin You can get a product.
Moreover, most of the resin sheet 2 is inserted deeply into the concave cavity of the movable mold 7, and the vacuum suction is performed in a state where the volume of the space S 1 is smaller than that of the conventional one and the sealing performance is enhanced by the vacuum seal member 9. Since it starts, it becomes possible to use a small-sized vacuum suction device, and the cost of equipment can be reduced.
[0020]
While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.
[0021]
【The invention's effect】
As described above, the sheet-bonding injection compression molding method according to the present invention has an end portion between a pair of molds each having a correspondingly shaped uneven portion and having a pattern engraved on the concave mold surface. And placing a preheated sheet while holding the mold movably, and inserting the majority of the sheet into the concave cavity of the other mold by the convex part of the one mold while closing the mold. And vacuum suction of the space formed by the concave mold surface and the product surface of the sheet, and the pair of molds are clamped to the mold alignment position while the vacuum suction is maintained and fully closed. Vacuum forming the sheet, transferring the pattern of the concave mold surface to the product surface of the sheet, opening the pair of molds, and the convex mold surface of the one mold Molten tree in the space formed by the anti-product surface of the sheet In Dressings containing the step of filling by injection compression molding, an end portion of the sheet, when the sheet is drawn into the recess cavity, the holding is released Runode to suppress wrinkles of the sheet surface, While preventing local spreading and breakage of the sheet, and ensuring good transferability from the mold surface to the sheet product surface, a resin product having excellent product surface and cushioning properties can be obtained. .
[0022]
The sheet sticking injection compression molding apparatus according to the present invention has any one of the correspondingly shaped concavo-convex portions, a pattern is engraved on the concave mold surface, and a vacuum seal member is provided around the concave portion. A pair of molds, a holding means for holding the end portion in a movable state so as to insert and arrange a preheated sheet between the molds, and a vacuum suction device for vacuum-suctioning the inside of the cavity of the mold And an injection device for injecting and filling molten resin into the cavity of the mold, the preheated sheet is placed on the vacuum seal member, and the end of the sheet is held by the holding means when the mold is closed The most part of the sheet is inserted by being shifted into the concave cavity of the other mold at the convex part of the one mold, and is formed by the concave mold surface and the product surface of the sheet The vacuum suction device Accordingly, vacuum suction is performed, and the pair of molds are clamped and fully closed while holding the vacuum suction, whereby the sheet is vacuum-formed and the pattern of the concave mold surface is transferred to the product surface of the sheet The pair of molds is further opened, and a molten resin is injected and filled into the space formed by the convex mold surface of the one mold and the anti-product surface of the sheet by the injection device, and the sheet and Since the molten resin is configured to be compression-molded, the same effects as those of the above invention can be obtained, and the equipment cost can be reduced by downsizing the vacuum suction device.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a conceptual diagram illustrating a stage of preheating a sheet for explaining a sheet pasting injection compression molding method and a molding apparatus for carrying out the same according to an embodiment of the present invention.
FIG. 2 is a conceptual cross-sectional view showing a stage in which a preheated sheet is placed between a pair of molds in a sheet pasting injection compression molding method according to an embodiment of the present invention.
FIG. 3 is a conceptual cross-sectional view showing a stage in which a sheet is inserted into a concave cavity while closing a mold and vacuum suction is performed in the method for sheet injection injection compression molding according to the embodiment of the present invention.
FIG. 4 is a conceptual cross-sectional view showing a stage in which a sheet is vacuum-formed in a fully closed state and a pattern is transferred to the product surface of the sheet in the sheet-attached injection compression molding method according to the embodiment of the present invention.
FIG. 5 shows a stage in which molten resin is filled in the space between the convex mold surface and the anti-product surface of the sheet in a mold open state at a predetermined position in the sheet-attached injection compression molding method according to the embodiment of the present invention. It is a conceptual sectional view.
FIG. 6 is a conceptual cross-sectional view showing a stage in which the mold is clamped and injection compression molded in the sheet pasting injection compression molding method according to the embodiment of the present invention.
FIG. 7 is a flowchart showing a procedure until a resin product is obtained by the sheet pasting injection compression molding method of the embodiment of the present invention.
FIG. 8 is a flowchart showing a procedure until a resin product is obtained by the sheet pasting injection compression molding method of the embodiment of the present invention.
FIG. 9 is a conceptual cross-sectional view showing a stage in which a preheated sheet is placed between a pair of dies, explaining a conventional sheet-bonding injection compression molding method and a molding apparatus for carrying out the method.
FIG. 10 is a conceptual cross-sectional view showing a stage in which a sheet is vacuum-formed in a mold-open state and a pattern is transferred to the product surface of the sheet in a conventional sheet-attached injection compression molding method.
FIG. 11 is a conceptual cross-sectional view showing a stage in which molten resin is filled in the space between the convex mold surface and the anti-product surface of the sheet in a state where the mold is closed to a predetermined position in the conventional sheet-bonding injection compression molding method. is there.
FIG. 12 is a conceptual cross-sectional view showing a stage in which injection compression molding is performed after clamping in a conventional sheet-attached injection compression molding method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Resin base material 1a Molten resin 2 Resin sheet 3 Elastomer layer 4 Foamed layer 5 Ceramic heater 6 Fixed side die 6a Convex part surface 7 Movable side die 7a Concave part surface 8 Sheet guide 9 Vacuum seal member

Claims (3)

A preheated sheet is placed between a pair of molds that have either one of the correspondingly shaped concavo-convex portions and the pattern is engraved on the concave mold surface, with the end portions being movably held. The mold is closed and the convex portion of the one mold inserts most of the sheet into the concave cavity of the other mold, and is formed by the concave mold surface and the product surface of the sheet. Vacuuming the space to be formed, and vacuum-molding the sheet by holding the vacuum suction and clamping the pair of molds to a mold-matching position and fully closing them, and Transferring the pattern onto the product surface of the sheet, opening the pair of molds, and injecting molten resin into the space formed by the convex mold surface of the one mold and the anti-product surface of the sheet adhesive tape and a step of filling by compression molding In out compression molding method, an end portion of the sheet, when the sheet is drawn into the recess cavity, the sheet laminated injection compression molding method, characterized in that the holding is released. The sheet-attached injection compression molding according to claim 1, wherein the sheet is a laminated sheet composed of an elastomer layer and a foam layer, and the pattern of the concave mold surface is transferred to the elastomer layer. Method. A pair of openable and closable molds having either one of the correspondingly shaped concavo-convex parts, a pattern is engraved on the concave mold surface, and a vacuum seal member is provided around the concave part, and between these molds In order to insert and arrange the preheated sheet, a holding means for holding the end portion in a movable state, a vacuum suction device for vacuum-sucking the inside of the mold cavity, and a molten resin in the cavity of the mold An injection device for injection filling, wherein the preheated sheet is placed on the vacuum seal member, and when the mold is closed, the end of the sheet is held by the holding means and the convex portion of the one mold The most part of the sheet is inserted while being shifted into the concave cavity of the other mold, and the space formed by the concave mold surface and the product surface of the sheet is vacuum sucked by the vacuum suction device. Do not hold the vacuum suction The pair of molds are clamped and fully closed to form the sheet in vacuum, and the pattern of the concave mold surface is transferred to the product surface of the sheet, and the pair of molds is opened. The molten resin is injected and filled into the space formed by the convex mold surface of the one mold and the anti-product surface of the sheet, and the sheet and the molten resin are compression molded. A sheet pasting injection compression molding apparatus characterized by the above.

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