JPH0623787A - Method for injection molding simultaneous with image application - Google Patents

Abstract

PURPOSE:To obtain a molded article improved in design feeling by a method wherein an image applying film is held and heated by a hot plate with a recessed part sectioned by a peripheral wall, the hot plate is brought into pressure contact with a female mold, the image applying film is expanded toward the hot plate and made to adhere to a female mold cavity surface, and a melt resin is injected into a cavity formed by female and male molds. CONSTITUTION:A hot plate 9 is disposed in a position between a male mold 51 and a female mold 52 aside of them. An image applying film X is pressed against a peripheral wall of a suction board 14 of the hot plate 9 by a film pressing frame 32 to be spread without a slack. This is carried to the front of the female mold 52. Meantime, the film X is heated and softened. After the film is carried in position, the hot plate 9 is brought into close contact with the female mold 52, and a vacuum is drawn between the hot plate 9 and the film X for expanding the film X toward the hot plate. By supplying a high-pressure compressed air, the film X is made to adhere to a female mold cavity surface. The hot plate 9 is separated from the female mold to be returned to a retracting position together with the pressing frame 32. After the female mold 52 and the male mold 51 are clamped, a melt resin is injected into a cavity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous injection-molding painting method, and more particularly to an injection-molding simultaneous painting method for improving the design feeling of a design formed on the surface of a molded product.

[0002]

2. Description of the Related Art Conventionally, a laminating method and a transfer method are known as a method for decorating a three-dimensional molded article. The laminating method is a method in which a film on which a pattern is printed is deformed, or after the film is deformed, the film is attached to a substrate, or after the film is deformed, a resin is filled therein and solidified. The transfer method is a method in which only the picture ink of a film on which a picture is printed in advance is transferred to a molded product.

The applicant of the present application has previously proposed an injection molding simultaneous painting apparatus applicable to both the laminating method and the transfer method (Japanese Patent Application No. 1082771). This proposal is to form a recess in a heating plate that softens the painting film, preheat while holding the painting film in the heating plate in a non-contact manner, and then close the painting film to the female mold cavity for injection molding. It's something that you do. By doing this, the inconvenience up to that point, that is, the "air bubbles" that were generated when the painted film was brought into close contact with the heating plate did not remain, and the traces of the holes for vacuuming provided on the heating plate "trace"
As a result, it does not remain on the surface of the molded product.

[0004]

However, according to the means disclosed in Japanese Patent Application No. 108271/1992, there are the following inconveniences depending on the shape of the female die. This inconvenience will be specifically described with reference to FIG.

As shown in FIG. 10, a male die 51 constituting an injection molding simultaneous painting apparatus is a female die 5 having a convex portion in the central portion.
An injection nozzle 55 is provided on the male mold 51 so as to communicate with the injection gate 54 so as to be opposed to the fixed plate 53. The female die 52 is fixed to a ram 57 via a movable plate 56, and is driven in a direction in which it separates from and comes in contact with the male die 51 by the advancing / retreating operation of the ram 57. Further, the female die 52 is provided with an exhaust hole 58 for exhausting the air in the female die 52 to the outside by using a vacuum pump (not shown) at the time of vacuum pressure forming of the painting film X described later. .

In such a structure, the painting film X is preformed on the female mold 52 in a softened state (state shown in the drawing). Then, the paint film X hardly extends in the range of the mark M ₁ (three places), but the paint film X significantly extends in the range of the mark M ₂ (two places). Note that the degree of elongation is schematically shown by the length of the arrow. Therefore, excessive stretching of the painting film is likely to be locally concentrated during preforming, and the painting film is torn or the printed pattern is greatly deformed.
Sometimes the painted film had cracks or wrinkles. That is, the design of the molded product may be impaired depending on the shape of the female mold.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide an injection molding simultaneous painting method in which the design feeling of the surface of a molded product is good.

[0008]

In order to achieve the above-mentioned object, the present invention heats a painted plate while holding the painted film on a heating plate having a concave portion defined by a peripheral wall, and heats the painted film to a female opening. The hot platen and the female mold are pressure-bonded through the painted film after being conveyed to a portion, and the painted film after pressure bonding is closely adhered to the cavity of the female mold, and the molten resin is formed in the cavity formed between the male mold and the mold. In the simultaneous injection-molding painting method of injecting with, the hot plate and the female mold are pressure-bonded via a painting film, first, the painting film is expanded to the heating plate side, and then, the painting film Was closely attached to the cavity surface of the female mold.

[0009]

[Function] The painted film is heated while being fixed in close contact with the top surface of the peripheral wall of the heating platen. At the time of this heating, the portion of the painted film that is brought into close contact with the female cavity is heated by the closed space through the recess and is brought into a non-contact state with the heating plate. Next, the painting film and the heating plate are conveyed to the opening of the female die, and the female die and the heating plate are pressure-bonded via the painting film. The softened painting film in this pressure-bonded state is inflated to the hot platen side (that is, the direction opposite to the female mold). After this reverse swelling, the painted film is brought into close contact with the cavity surface of the female mold, and molten resin is injected. By including the step of reverse swelling in this way, the decorative film is stretched as a whole, so local stretching can be prevented, and a molded product having a good design feeling can be obtained.

Further, the through-holes and / or surface irregularities of the hot platen do not come into contact with the portion closely contacted with the cavity, and the traces of the through-holes do not remain in the molded product.

[0011]

The present invention will be described below with reference to the illustrated embodiments. In addition, the same reference numerals are given to the parts already described, and the duplicated description will be omitted.

FIG. 1 shows an overall schematic structure of an injection molding simultaneous painting apparatus used in the present invention. As shown in FIG.
The hot platen 9 is arranged at a side position (upper position) between the female mold 52 and the female die 52. Mold 5 "
It is configured to laterally move between the carry-in position between 1, 52. The heating plate 9 adsorbs the decorative film X at the side position, that is, the standby position, and moves to the carry-in position to supply the decorative film X between the molds 51 and 52. Then, the heating plate 9 heats the adhering picture film X to moderately soften it while moving from the standby position to the carry-in position. Further, the painted film X is adsorbed from the hot platen 9 to the cavity forming surface 52a of the female die 52 by vacuum pressure forming in the loaded state. Therefore, the hot platen 9 is a surface facing the female die 52 (a surface holding the painted film).
Adsorb the painting film X on the side.

2 and 3 show the detailed construction of the hot platen 9. As shown in FIG. As shown in FIG. 2 and FIG. 3, the heating plate 9 includes a heating plate 10 and a liner plate 1 from the side on which the painting film X is adsorbed.
1, a heater plate 12, and an insulating plate 13 are combined and laminated in this order, and a frame-shaped adsorption plate 14 is attached to the surface of the heating plate 10. The suction plate 14 is deeper than the cavity depth of the female die 52. Hot platen 9
Supported on the support member 15 by solenoids 16 and 16,
By operating the solenoids 16 and 16, the hot platen 9 can be moved in a direction perpendicular to the carrying-in direction. In that case, the moving direction of the solenoids 16 and 16 is the female die 5.
It is a direction toward and away from 2.

In the heating plate 9, the heating plate 10 is composed of a metal plate having excellent thermal conductivity, and the peripheral wall 14a of the adsorption plate 14 is used.
A large number of small-diameter air blowing holes 17 to 17 penetrating the front and back are arranged at a predetermined pitch in a portion surrounded by. The peripheral wall 14a of the heating plate 10 and the suction plate 14
By the above, the concave portion 14b is sectioned and formed. The radiation efficiency can be improved by forming a ceramic layer on the surface of the heating plate 10. The liner plate 11 arranged on the back surface side of the heating plate 10 is also made of a metal plate having excellent thermal conductivity, and a groove for supplying compressed air to the air blowing holes 17 to 17 on the surface portion in contact with the back surface of the heating plate 10. 18 is formed, and an air passage 19 is provided at the center of the liner plate 11 so as to communicate with the groove 18. The air passage 19 also penetrates through the central portions of the heater plate 12 and the insulating plate 13 and is opened in the back surface of the insulating plate 13, and the air hose 2 is provided in the opening.
0 is connected. And this air hose 20
A three-way switching valve 21 is connected to switch between a low pressure compressor 22 and a high pressure compressor 23.

A large number of heaters 24 to 24 are arranged inside the heater plate 12, and these heaters 2 to 24 are provided.
Wiring (not shown) is provided to supply power to 4 to 24. The insulating plate 13 has a function of effectively transmitting the heat generated by the heaters 24 to 24 to the heating plate 10.

On the other hand, the peripheral wall 14a of the suction plate 14 has an O-ring fitting groove 25 on the surface thereof as shown in FIGS. 3 and 4 (enlarged view of a portion A in FIG. 2).
Is formed in an annular shape along the peripheral wall 14a of the
The ring 26 is fitted. The O-ring 26 can prevent air leakage to the outside and deviation of the painting film during vacuum forming.

With respect to the hot platen 9 having such a structure, a film pressing means 31 is provided at a standby position of the hot platen 9 so as to face it (see FIGS. 1 and 2). This film pressing means 3
1 is a film holding frame 32 (see FIG. 6), an air cylinder 33 for moving the film holding frame 32 in a direction orthogonal to the heating plate 9, and a holding frame 32 for the heating plate 9 and the mold 5.
It has a drive mechanism (air cylinder, etc., not shown) for moving it in two directions. According to the pressing frame 32, the painted film X can be spread and can be heated and held in a completely non-contact manner. The film pressing means 31 includes a film pressing frame 32.
In order to cut the drawn decorative film X into a predetermined size, chuck means 34 for drawing the decorative film X between the heated platen 9 and the film holding frame 32 in a state where the drawn decorative film X is separated from the heated platen 9. And a cutter means 35 driven by an air cylinder 36.

That is, the picture film X is an arbitrary picture Y.
(See FIG. 3) has a band shape drawn at regular intervals, and is wound and set in a roll shape on a film setting unit (not shown). Then, the chuck means 34 grabs the end of the painted film X and moves it from the film setting section to the heating plate 9
Is configured to be pulled out by a predetermined length on the front surface of the. In this case, the amount of drawing out is long enough to supply the pattern portion necessary for one-time resin molding to the front surface of the hot platen 9, and the painted film portion having this pattern Y is the film pressing frame 3
It is pressed against the hot platen 9 by 2. When the film is pressed, the peripheral wall 14a of the suction plate 14 of the hot platen 9 is pressed by the film pressing frame 32 so that the peripheral portion surrounding the pattern Y is pressed and stretched without causing a lump, and in this state, the cutter means 35 is used. Cuts the decorative film X and separates the pressed decorative film portion.

Next, the simultaneous injection-molding painting method of this embodiment will be described with reference to the time chart shown in FIG. First, with the hot platen 9 shown in FIGS. 1 and 2 in the standby position and the film pressing frame 32 separated from the hot platen 9, the chuck means 34 is moved to the front position of the hot platen 9 as described above. The painted film X is drawn in (step S1), and the drawn film X is drawn into the film holding frame 32.
Is pressed against the front surface of the heating plate 9 (step S
2). Further, the air passage 19 and the groove 18 are communicated with the low-pressure compressor 22 by the three-way switching valve 21, and the low-pressure air from the low-pressure compressor 22 is blown out little by little from the air blowing holes 17 to 17 provided in the heating plate 10. After that, the film is cut by the cutter means 35 (steps S3 and S4). The amount of air blown out from the air blow holes 17 to 17 is adjusted so that the painting film X forms a plane parallel to the heating plate and does not deviate from the suction plate 14 or cause a lump. If it is unnecessary, the blowing does not have to be performed.

Then, the film pressing frame 32 and the hot platen 9 are moved between the molds 51 and 52, and the picture film X is transferred to the female mold 5.
It is carried in front of 2. After this loading, by keeping the communication between the vacuum pump 30 and the low-pressure compressor 22 by the respective three-way switching valves 21, 29, the painted film X keeps a flat plane parallel to the hot platen 9 without causing a tarmi, and the suction plate. Air is adsorbed on the peripheral wall 14a of the air conditioner 14 and air is blown between the painting film X and the heating plate 10. Therefore, the painted film X is carried in in a flat state (non-contact state) in which it does not contact the surface of the heating plate 10. The heating plate 9 is heated by the heaters 24 to 24.
Since the coating film X is heated, the painting film X is moderately softened by being heated by the radiant heat from the heating plate 10 and / or the transfer heat via air during the period from the adsorption to the completion of the loading. The painted film X is made of a thermoplastic resin film because it needs to be softened by heating. The degree of softening is not less than the softening temperature (defined by Vicat softening temperature etc.) of the thermoplastic resin and not more than the melting temperature. .

After the loading, the solenoids 16 and 16 are excited.
As a result, the hot platen 9 moves toward the opening of the female die 52
Is moved (step S5), and as shown in FIG.
They are contacted (step S6). Next, the female mold 52 is at atmospheric pressure.
(Step S7), the pressure P in the heating plate 9₁And female 5
Pressure P in 2₂Means "P₁= P₂It is. continue,
As shown in FIG. 7 (B), the hot platen 9 is switched in three directions.
By switching operation of the flap valves 21 and 29, the respective air passages are
A vacuum pump 30 is connected to the passages 19 and 27, and
By doing so, the painted film X swells to the hot platen 9 side. in this case,
Painted film X stretches evenly over the entire surface (step
S8). Due to this vacuuming, the pressure P ₁And P₂Seki
The person in charge is "P₁<P₂It will be.

Then, in the hot platen 9, the respective air passages 1 are switched by the switching operations of the three-way switching valves 21 and 29.
The high-pressure compressor 23 is connected to 9, 27, and high-pressure compressed air is blown out from the air blowing holes 17 to 17.
By this blowing, as shown in FIG. 7C, the painting film X is brought into close contact with the cavity forming surface 52a of the female die 52, and the relationship between the pressures P ₁ and P ₂ at this time is “P ₁ >
P ₂ ”(step S 9). That is, vacuum pressure forming on the die of the film. Also, in step 9,
Desirably, vacuum suction is performed using the female suction port, and residual air between the sheet and the female mold is eliminated, which is preferable.

Subsequently, as the hot platen 9 is separated from the female die 52 and returned to the standby position together with the film pressing frame 32 (step S10), the female die 52 and the male die 51 are joined by the operation of the ram 7. (See FIG. 8), both molds 5 in the mold clamped state
Molten resin is discharged into the cavities in 1, 52 and resin molding is performed (step S11), and at the same time, the pattern Y of the decorative film X is transferred to the resin molded product for painting.

As described above, in the process of adsorbing the decorative film X by the hot platen 9 and carrying it in between the molds 51 and 52 while heating, the decorative film X is attached to the peripheral wall 14a of the adsorption plate 14 only in the peripheral portion of the pattern. And the pattern portion is floated from the concave portion 14b formed by the suction plate 14, and a small amount of low pressure air is blown between the painting film X and the heating plate 10 to force the floating state. Since it is kept on, the heating plate 10 is attached to the design Y part of the painting film X.
The shape of the air blowing holes 17 to 17 that are opened in the area does not become uneven. Therefore, the surface of the resin product is not uneven, and unnecessary change in gloss does not occur.

Further, as shown in FIG. 7B, the expansion amount of the painting film X is made uniform by inflating the painting film X once in the opposite direction, so that the state shown in FIG. Even if it comes into close contact with the cavity surface 52a), local stress concentration does not occur. Therefore, it is possible to manufacture a molded article having an excellent design feeling without impairing the design feeling as in the conventional case.

The "positioning of the decorative film and the mold" and "timing of heating the decorative film and conveying it to the mold" may be as follows. When always producing a large number of products with the same relative positional relationship between the pattern on the positioning surface of the paint film and the mold and the shape of the molded product (all shots),
Positioning is performed so that the relative position between the design on the painting film X and the heating plate 9 is the same every time. The hot platen 9 and the female die 5
If the relative position when closely contacting with 2 is fixed in advance in a predetermined relationship, the positional relationship between the design and the mold, and further, the design and the molded product is reproduced in the same manner for each shot.

A specific method for positioning may be a known method. For example, when printing a film with a picture, a register mark (a cross-shaped pattern, etc.) for aligning the film flow method and the width direction with a fixed positional relationship relative to the picture.
Is printed in advance. Then, a sensor such as a photoelectric tube that detects sensor marks in the flow direction and the width direction is installed at a predetermined position of the injection molding machine, for example, at an upstream portion of the mold.
A flow direction drive device and a width direction drive device (step motor, etc.) whose operation, stop, etc. are controlled by a detection signal from this sensor are provided.

Then, in step S1, the drive device for driving the chuck means 34 in the flow direction is stopped when the flow direction sensor detects the flow direction, and then the chuck means 34 is laterally driven while being driven in the width direction. When the direction sensor detects the width sensor mark, by stopping the drive device that drives in the width direction, the relative position of the pattern with respect to the heating plate 9 becomes a predetermined position (beside the sensor, the sensor and the sensor). Set the position of the mark). Then, step S2 is entered.

Of course, this positioning may be omitted when the relative positional relationship between the design and the shape of the molded product does not have to be made uniform for each shot. Timing of heating of the decorative film and transfer to the mold In the present embodiment, the case where the decorative film X adhered to the heating plate 9 is simultaneously transferred to the mold part and simultaneously heated is described. In order to shorten the molding cycle, such a mode is preferable, but of course, the heating can be started after the painting film X is loaded into the mold part.

Further, although the transfer method has been described in this embodiment, the present invention can be applied to the laminating method. Furthermore, in the present embodiment, a panel heater that radiates near infrared rays is used as a heater, but in addition to this, an electric heater (radiation of Joule heat of a nichrome wire, a sheet resistor, etc. is directly radiated to the painting film. ), A ceramic-containing panel heater that radiates far infrared rays, dielectric heating, or the like. Further, the heat transfer to the painted film may be carried out by directly utilizing the radiant rays of infrared rays, electromagnetic waves, or the like, or by heating the air in the closed space once and then transferring it to the film X from here. Of course, both may be used together.

[0031]

As described above, according to the present invention, when the prepainted film is preheated, it is heated in a non-contact manner, so that the heating plate and the painted portion of the painted film do not come into contact with each other. Therefore, no trace of the through hole of the heating plate remains on the painted film, and this trace does not remain on the molded product. In addition, since the decorative film is inflated in the direction of the heating plate before the decorative film is brought into close contact with the cavity surface, the decorative film can be evenly spread, and local stress concentration occurs when it comes into close contact with the cavity surface. do not do. Therefore, a molded product having a good design feeling can be provided.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of an injection molding simultaneous painting apparatus used in an embodiment of the present invention.

FIG. 2 is a side view including a partial cross section of a heating plate in the apparatus.

FIG. 3 is a front view of the hot platen.

FIG. 4 is an enlarged sectional view of a main part of the hot platen.

FIG. 5 is a view showing a state in which a picture film is sandwiched by a hot platen and a pressing means in the apparatus.

FIG. 6 is a perspective view showing a holding frame in the apparatus.

FIG. 7 is a diagram showing a process until the decorative film is adsorbed by the female mold in the above-mentioned embodiment, (A) is a state immediately after the decorative film is pressure-bonded with the hot platen and the female mold, and (B) is a diagram. It is a figure which shows the state which expanded the painting film which concerns on the summary of this invention to the heating plate side, and (C) the state which stuck the painting film to the female type | mold.

FIG. 8 is a diagram showing a state immediately before injecting a molten resin in the example.

FIG. 9 is a time chart showing the operation of the embodiment.

FIG. 10 is a conceptual diagram showing an inconvenience in a conventional simultaneous injection molding painting method.

[Explanation of symbols]

9 ... Hot platen 10 ... Heating plate 14 ... Adsorption plate 14a ... Adsorption plate peripheral wall 14b ... Recessed portion 17 ... Air blowing hole 32 ... Film pressing frame 51 ... Male mold 52 ... Female mold 52a ... Cavity constituting surface P ₁ , P ₂ ... Pressure in hot platen and female mold X ... Painted film

Claims (1)

[Claims] 1. A heating plate holding a painting film on a heating plate having a concave portion defined by a peripheral wall, heating the heating painting film, conveying the heated painting film to an opening of a female mold, and thereafter, heating the heating plate and the female mold with the painting film. Injection molding simultaneous painting method in which pressure is applied through a film, the painting film after crimping is brought into close contact with the female mold cavity, and molten resin is injected into the cavity formed between the male mold and painting on the molded product. In the above, after the hot platen and the female mold are pressure-bonded via a decorative film, first, the decorative film is swelled to the hot platen side, and then the decorative film is brought into close contact with the cavity surface of the female mold. Injection molding simultaneous painting method.