JPH07156201A - Method and device for foil decorating simultaneously with injection molding - Google Patents

Abstract

PURPOSE:To provide a device and a method for foil decorating simultaneously with injection molding wherein injection molding is performed by inserting a band-like decorated sheet into a mold so as to decorate with foil simultaneously with the molding, and the decorated sheet can be punched by in-line system. CONSTITUTION:A decorated sheet 3 is arranged between a female mold 1 and a male mold 2 of a simultaneously decorating injection molding device. After pre-forming by the female mold 1, the mold is clamped and a melting resin 42 is injected from an injection nozzle 24 arranged at the male mold 2 so as to integrate the decorated sheet and a molded piece 41. During the mold clamping, while a vibration punching blade 11a and an auxiliary vibration punching blade 11b are vibrated by a vibration generating device 12, the vibration punching blade 11a is advanced and the auxiliary vibration punching blade 11b is retracted by a back-and-force move device 13, and the decorated sheet is punched by in-line system. Thereafter, the mold is opened so as to obtain a molded piece decorated with foil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a manufacturing method and an apparatus for painting an injection-molded article simultaneously with molding.

[0002]

2. Description of the Related Art Conventionally, as a technique for producing a decorative molded article, a decorative sheet having a print layer formed on a base film having good moldability is placed in an injection molding die, and a synthetic resin is injection molded. A method for obtaining a molded product in which a pattern is integrated by performing the above is widely used. For the decorative sheet, Japanese Patent Publication Sho 33-3
As disclosed in Japanese Patent Publication No. 180, Japanese Patent Publication No. 50-19132, etc., a type in which a base material film is provided with a pattern printing so as to be laminated and integrated with a molded article simultaneously with injection molding, and Japanese Patent Publication No. 51-33456. As described in Japanese Patent Publication No. 2-4080, etc., a base film has a release layer,
There is a type in which a film in which a pattern printing layer and an adhesive layer are laminated is used and the base film is peeled off after molding.

If the molded product has a complicated shape or a deep-drawn shape, it is necessary to preform the decorative sheet. There has been attempted a method in which a female die of an injection molding die is used as a vacuum molding die for preforming, and then the male die and the female die are clamped and a synthetic resin is injected to perform the molding. According to this method, a vacuum molding die is unnecessary, and injection molding can be performed immediately after preliminary molding, which is efficient.

However, in any of the methods, it is necessary to cut and punch the painting sheet after demolding (die opening),
As a method of cutting and punching out the surplus painting sheet around the molded product in-line during molding,
As disclosed in Japanese Patent No. 41 and Japanese Patent Application Laid-Open No. 61-63425, a blade is provided to shear the female and male cavities while they are fitted to each other. A method has been used in which a sheet is cut and punched and then a molten resin is injected into a mold to obtain a molded product.

[0005]

When the punching of the painting sheet is sheared by the fitting of the two molds, the fitting accuracy of the blade portions provided in the two molds is required, and high working accuracy is required. . If there is a gap in the fitting of the peripheral edges of both molds due to an error in processing accuracy or wear of the blade over time, not only punching will not be possible, but the airtightness inside the cavity will deteriorate, resulting in a molded product. Bubbles may be generated and the injection resin may leak from the cavity. In addition, since the resin is injected onto one already-punched painting sheet, the resin wraps around from the peripheral edge of the painting sheet to the back surface (between the painting sheet and the female mold), causing variations in the painting molded product. Product yield will be poor. Furthermore, the position of the painting sheet and the mold are easily misaligned, and the positional accuracy of the molded product and the pattern deteriorates,
There is a problem with products that require pattern positional accuracy with respect to molded products.

[0006]

In an injection molding simultaneous painting method in which a painting sheet is inserted between a female mold and a male mold of an injection molding apparatus to perform injection molding, a peripheral portion of a mold cavity is surrounded. In addition, a pair of vibration punching blades provided so as to sandwich the painting sheet from both the front and back sides mechanically excites vibrations in the blade during injection molding or until the mold is opened after injection molding. While moving the other blade backward and locally heating and cutting the surplus sheet around the molded product, both molds are opened and the painting injection molded product is taken out. Further, in an injection molding apparatus that inserts a painting sheet between the female mold and the male mold of a mold and performs painting simultaneously with injection molding, the periphery of the mold cavity is surrounded and the painting sheet is attached. A pair of blades sandwiched from both front and back sides are provided on both molds, and further, a vibration generator for vibrating the pair of blades, a drive unit for moving forward and backward, and a heating unit for heating. Is a simultaneous injection molding painting device provided in the mold.

[0007]

According to the present invention, a strip-shaped decorative sheet is inserted into a mold, injection molding is performed, and after a molded product is painted,
Since the decorative sheet is punched out in-line by locally heating and melting without using the shearing stress of the blade, the molded product and the pattern can be accurately synchronized with each other without lowering the productivity.

[0008]

The present invention will be described in detail below with reference to the drawings based on the embodiments. FIG. 1 is a schematic explanatory view of an example of an apparatus for producing a decorative molded product by the simultaneous injection molding decorative apparatus of the present invention. 2 to 7 are views showing the procedure of the simultaneous injection molding painting method of the present invention. 8,
FIG. 9 is a perspective view and a cross-sectional view of a vibration punching blade for punching out a painting sheet. FIG. 10 is an explanatory diagram when the vibration punching blade is attached to both molds. FIG. 11 is a diagram showing a vibration waveform of the vibration punching blade. FIG. 12 is a view showing a method of mounting a vibration generator for making the vibration of the vibration punching blade into a circulating traveling wave, and FIG. 13 is a view showing voltage waveforms of respective phases of n-phase alternating current.

The injection molding simultaneous painting method and apparatus of the present invention will be described below in accordance with procedures. As shown in FIG. 1, a painting sheet 3 is supplied by winding a pattern such as wood grain printed on a base material, and as a belt-like sheet between a female mold 1 and a male mold 2 of an injection molding apparatus, Supplied continuously. At this time, the registration mark 9 (see FIG. 7) is printed on the painting sheet, and the sheet is conveyed by the sensor to catch the registration mark 9 for one pitch corresponding to the size of the molded product. Will be sent accurately. When the sheet is supplied, the heating platen 4 for heating the sheet is retracted to a position away from the injection molding device. From the viewpoint of continuous productivity, it is preferable to supply the decorative sheet as a belt-shaped continuous sheet (web), but it is also possible to supply it as a single sheet. Also, the sensor mark is indispensable when the positions of the molded product shape and the pattern are synchronized with each other with high accuracy, but can be omitted when the pattern positions need not be synchronized.

As the painting sheet, either a transfer sheet in which a pattern is printed on a base material sheet or a laminate sheet can be used. The base material sheet includes thermoplastic resins such as polypropylene, polyolefins such as polyethylene, polyethylene terephthalate, thermoplastic polyesters such as polybutylene terephthalate, polyvinyl chloride, acryl, polystyrene,
Nylon, ABS, etc. can be used. Thickness is usually 25-5
It is about 00 μm and is supplied as a sheet or a continuous strip.

The above injection molding simultaneous painting apparatus is provided with a female mold and a male mold, and after molding both molds, a molten resin is injected into the mold from a nozzle gate to perform molding. Then, it basically has the same configuration as the conventional injection molding machine. That is, the female die 1 is fixed to the movable platen 5,
Is a male mold 2 with a hydraulic cylinder 21 and a piston 22.
You can move in the direction of. The male mold 2 is fixed to a stationary platen 6, and a molten resin injection nozzle 24 is provided therein.

The simultaneous injection-molding painting apparatus of the present invention comprises a pair of vibration punching blades 11a for punching a painting sheet.
And a sub-vibration punching blade 11b. This vibration punching blade 11a is attached to the male die 2,
It is shaped so as to surround the core of the male mold 1 and the peripheral edge of the cavity of the female mold, and its tip is sharpened like a cutting edge. On the other hand, the sub-vibration punching blade 11b is attached to the female die 1 so as to surround the cavity of the die, and its shape is the same as that of the vibration punching blade 11a, but the tip of the blade is a flat surface. . The vibrating punching blade 11a and the sub-vibrating punching blade 11b are connected to the advancing / retreating device 13 by a fixing jig and a supporting rod so that they can be moved forward and backward in the horizontal direction. Further, the vibration punching blade 11a and the sub-vibration punching blade 11b are provided with a vibration generator 12 for vibrating and heating the painting sheet, so that the vibration punching blade 11a can move forward and backward while vibrating. Vibration punching blade 11a attached to both molds
And the sub-vibration punching blade 11b move forward and backward to vibrate and heat the painting sheet.

Next, the injection molding simultaneous painting method of the present invention will be described according to the procedure. As shown in FIG. 2, a belt-shaped painting sheet 3 is arranged between the female mold 1 and the male mold 2 of the injection molding apparatus, and the heating plate 4 is moved to contact the sheet to make the female mold. The sheet is heated while being pressed against the flange portion (parting surface) of the mold 1. Next, as shown in FIG.
A vacuum pump (not shown) sucks through the air intake holes 25 of the female mold 1 to reduce the pressure inside the cavity 7 of the female mold 1, pre-form the painting sheet, and Stick it to the cavity wall. This preforming is indispensable when the unevenness of the mold is large and the amount of deformation accompanying the molding of the painting sheet is large, but when it is not, this preforming can be omitted.

As shown in FIG. 4, the hydraulic cylinder 21 is used to push the moving plate 5 of the female die 1 with the piston 22 to clamp the female die 1 and the male die 2, and the male die 2 is clamped. From the injection nozzle 24 provided in the mold 2 to the gate (gate) 23
Injection molding product 4 by injecting molten resin 42 into the mold through
At the same time as 1 is made, it is adhered to the preform of the painting sheet 3 to obtain a painting molding.

As the resin, a thermoplastic resin which can be injection-molded is usually used, but it is also applicable to RIM molding (reactive injection molding) using a reactive curable resin solution. As the thermoplastic resin, polystyrene, polyvinyl chloride,
Examples of reaction-curable resins for ABS, polypropylene and the like include polyurethane isocyanates composed of isocyanate and polyol, organic sulfonates, unsaturated polyesters having benzoyl peroxide as a curing agent. The molten resin used here includes both a liquid resin at room temperature and a solid resin melted at room temperature by heating.

While performing mold clamping and injection molding, FIG.
As shown in, the vibrating punching blade 11a and the sub-vibrating punching blade 11b attached to the male die 2 and the female die 1 are horizontally advanced and retracted to punch out the painting sheet. That is,
The vibration punching blades 11a and the sub-vibration punching blades 11b are respectively subjected to a frequency of 5
Vibration heating is performed by exciting with a sine wave of 0 hertz and one-sided amplitude of 0.25 mm. As described above, when both blades are vibrated, the painting sheet self-heats along the shape of the blades, softens, and becomes a flowable state.

The vibration generator 12 comprises a vibrator 14 and a power cord (hereinafter referred to as an electric wire) 15. The excitation frequency may be selected from the audible frequency range of about 15 Hz to 1 MHz and the ultrasonic frequency range depending on the material of the sheet, the thickness, the shape of the blade, and the like. It may be adjusted appropriately. As the vibration generator, various types such as a piezoelectric type and a magnetostrictive type can be used.

The advancing / retreating device 13 of the vibrating punching blade 11a is operated to move it forward in the direction of the female die 1, and the advancing / retreating device 13 of the sub-vibrating punching blade 11b is retracted to vibrate the fusing sheet in the molten state. Punch into shape. When the drawing sheet is completely punched out, the advancing / retreating device 13 for the male die moves backward, and the advancing / retreating device 13 for the female die moves forward to return to the original position.

Next, the mold is opened as shown in FIG. 6, and the decorative molded product is taken out. As shown in FIG. 7, the decorative molded product 42 is taken out with the burrs 43 attached, and the remaining decorative sheet becomes as shown in FIG. It is sent pitch by pitch, and a new painting sheet is sent between the molds to move to the next injection molding process.

As shown in FIG. 8, the vibration punching blade 11a and the sub-vibration punching blade 11b are composed of a punching blade, a blade fixing jig, four support rods, a vibrator and an electric wire. The punching blades 31a and 31b have a shape as shown in FIG.
It is fixed to. In the case of the punching blade 31a, the tip shape of the cutting edge is sharpened like the cutting edge, as shown in FIG. 9 (b), and in the case of the punching blade 31b, the shape of FIG.
As shown in (a), the tip is flat.

FIG. 10 is a view showing the case where the above-mentioned vibration punching blade is attached to both molds. As shown in FIG. 10 (a), the punching blade 31b surrounds the cavity 7 of the female mold. , The support rod 3 connected to the punching blade 31b
It can be moved forward and backward in the mold by moving 2. Further, the punching blade 31a surrounds the core 8 of the male mold, but the size thereof is the punching blade 31b.
When punching out a painting sheet, the support rod 32 is moved so that the female die 1 can be inserted.

In order to vibrate the punching blade, a vibration generator attached to the jig for fixing the blade excites a sine wave having a frequency of 50 cycles and a single amplitude of 0.25 mm. It vibrates in a waveform. Due to this vibration, the vibration punching blade 11a and the sub-vibration punching blade 11
The painting sheet sandwiched between b is self-heated and softens according to the shape of the blade, and becomes a fluidized state. The mounting position of the vibration generator is not particularly specified as long as it is a place where the punching blade is vibrated, such as a connecting portion between the support rod and the advancing / retreating device, other than the above.

As a mode of vibration, in addition to the standing wave, it is also possible to excite the wave front to be a traveling wave in which the wave front circulates clockwise or counterclockwise along the outer periphery of the vibration punching blade and the sub-vibration punching blade. Specifically, as shown in FIG. 12, N vibration generators are arranged at substantially equal intervals in the outer peripheral direction of the punching blade 31a and the punching blade 31b, and the vibration generators 12 ₁ , 12 ₂ , 12 ₃ , ..... 12 _N , FIG.
3, such as, n-phase AC _{φ 1, φ 2, φ 3} , ···· φ n
By sequentially connecting and sequentially exciting, the tip of the punching blade causes a traveling wave that circulates in the outer peripheral direction (see FIG. 1).
3 (a)-(d)). By doing so, a shearing stress or a frictional force circulating in the outer peripheral direction can be applied to the tip of the punching blade, and the punching can be performed more efficiently.

[0024]

EFFECTS OF THE INVENTION According to the present invention, the painting sheet is inserted into the mold, injection molding is performed, and after painting the molded product, the painting sheet is punched out inline.
It is possible to obtain an accurate painted molded product without lowering productivity. In addition, the blade is less likely to be worn or deformed.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an injection molding simultaneous painting apparatus of the present invention.

FIG. 2 is a diagram in which a painting sheet is arranged between a female mold and a male mold.

FIG. 3 is a diagram of a decorative sheet preformed by vacuum forming using a female die.

FIG. 4 is a view in which the decorative sheet is preformed in FIG. 3 and then the mold is clamped and injection-molded.

FIG. 5 is an explanatory view of when a decorative sheet is punched out by a vibration punching blade after injection molding.

FIG. 6 is a state diagram when the mold is opened after injection molding and punching of a painting sheet.

FIG. 7 is a diagram showing the remaining decorative sheet and the decorative molded product after punching.

FIG. 8A is a perspective view of a sub-vibration punching blade. (B) A perspective view of a vibration punching blade.

9A is a cross-sectional view of the punching blade 31b taken along the line XX. FIG. (B) Sectional drawing of the YY surface of the punching blade 31a.

FIG. 10 (a) is an explanatory view when the sub-vibration punching blade is attached to the female die, and (b) is an explanatory view when the vibration punching blade is attached to the male die.

FIG. 11A is a diagram showing a vibration waveform of a vibration punching blade. (B) An enlarged view of a part of the vibration waveform of the vibration punching blade.

FIG. 12 is a view in which a vibration generator is attached to change the vibration of the punching blade into a circulating traveling wave.

FIG. 13 is a diagram showing a voltage waveform of each phase of n-phase alternating current, and (a) A diagram showing a waveform of a first-phase alternating-current voltage. (B) The figure which shows the waveform of the alternating voltage of a 2nd phase. (C) The figure which shows the waveform of the alternating voltage of a 3rd phase. (D) The figure which shows the waveform of the alternating voltage of a nth phase.

[Explanation of symbols]

 1 Female mold 2 Male mold 3 Painting sheet 4 Heating plate 5 Moving plate 6 Fixed plate 7 Female mold cavity 8 Male mold core 9 Registration mark 11a Vibration punching blade 11b Sub-vibration punching blade 12 Vibration Generator 13 Advance / Retract Device 14 Vibrator 15 Electric Wire 21 Hydraulic Cylinder 22 Piston 23 Injection Gate 24 Injection Nozzle 25 Intake Hole 26 Suction Connection Pipe 31a Punching Blade (for Vibration Punching Blade) 31b Punching Blade (for Sub-Vibration Punching Blade) 32 fixed support rod 33 punching blade fixing jig 34 female mold flange 35 male mold flange 41 injection molded product 42 molten resin 43 painting molded product 44 molded product burr φ excitation voltage

Claims (2)

[Claims] 1. In an injection molding simultaneous painting method in which a painting sheet is inserted between a female mold and a male mold of an injection molding device to perform injection molding, a peripheral edge of a mold cavity is surrounded and a picture is drawn. With a pair of vibration punching blades provided so as to sandwich the attachment sheet from both the front and back sides, mechanical vibration is excited in the blade during injection molding or until the mold is opened after injection molding, and one blade is advanced, Injection molding simultaneous painting method characterized by obtaining a painted injection-molded product by reversing the other blade and locally heating and cutting the surplus sheet around the molded product and then opening both molds. . 2. In an injection molding apparatus for inserting a painting sheet between a female die and a male die of a die to perform painting simultaneously with injection molding, the periphery of the die cavity is surrounded and the painting is performed. A pair of blades for sandwiching the attachment sheet from both front and back sides are provided in both molds, and further, a vibration generator for vibrating the pair of blades and a drive device for moving forward and backward are provided in the mold. An injection molding simultaneous painting device, which is provided in the.