JP3043681B2 - Injection molding simultaneous painting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for simultaneously painting a surface of a molded article with injection molding.

[0002]

2. Description of the Related Art Conventionally, a laminating method and a transferring method have been known as a decorating method for a three-dimensional molded article. In the laminating method, a film on which a pattern is printed in advance is deformed or bonded to a substrate at the same time as the deformation, or resin is applied to the film in the molding cavity between the male and female molds during or after the deformation of the film. Fill. On the other hand, in the transfer printing method, only a pattern ink of a film on which a pattern is printed in advance is transferred to a molded article.

A transfer printing method is disclosed in Japanese Patent Application Laid-Open No. 62-196.
The method described in JP-A-113 is known. In this method, as will be described later, a hot plate on which a picture film is adsorbed is moved into a space between a male die and a female die separated from each other at a predetermined interval. Next, the painting film is heated by a hot plate and is vacuum-sucked to the inner surface of the female mold. Thereafter, the hotplate is retracted outward from the space between the male and female molds. Next, the male mold and the female mold are fastened to each other. Then, the molten resin is injected into the cavity defined by these halves to form a molded product, and the painted film is adhered to the surface of the molded resin molded product.

However, in this method, when the painted film is adsorbed on the hot platen, air is trapped between the hot platen and the painted film, and this air remains as air bubbles. Therefore, the painted film is not heated uniformly. In addition, the unevenness or indentation of the vacuum hole of the hot plate remains on the surface of the final molded product to which the painting film is adhered, so that the appearance of the molded product becomes poor.

In order to solve this problem, Japanese Patent Laid-Open No. 5-3 is disclosed.
No. 01250 (Japanese Patent Application No. 4-108271) has been proposed. In this method, a rectangular holding frame that comes into contact with the surface of the painting film is protruded from a peripheral portion of the surface of the hot plate, and a concave portion is formed inside the holding frame. Then, when the hot platen holds the painting film for heating the painting film, the presence of the concave portion prevents the main part of the painting film from coming into contact with the surface of the heating plate. Indentations remain on the film,
Deterioration of the appearance of the molded article is avoided.

[0006]

However, in the above-described simultaneous injection molding painting method, the following problems remain.

That is, when the painted film is conveyed to the female mold for positioning while holding the painted film on a hot plate and heating and softening, wrinkles and sagging of the film occur due to the transport of the softened painted film. Alignment with the female mold is not always accurate because of the softening of the film. In addition, the influence of the molding operation on the painted film in the molding apparatus, that is, the influence of the deformation, the generation of stress, and the like of the painted film is likely to affect the upstream painted sheet.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to send a painted film to a position facing a female mold surface without wrinkles or sagging,
In addition, it is an object of the present invention to provide a simultaneous injection molding painting method in which the positioning of the picture of the painting film with respect to the female mold and the fixing of the painting film can be performed accurately, and the influence of the molding operation does not affect the upstream painting sheet.

Another object of the present invention is to provide a simultaneous injection-molding painting method capable of quickly releasing the fixation of the painting film to the female mold without affecting the removal of the molded article after the mold is opened. It is in.

It is still another object of the present invention to provide a simultaneous painting method for injection molding, which can reliably hold and fix a painting film to a female mold.

[0011]

According to the present invention, a painting film is fed to a position between the opposite male and female molds of the simultaneous injection molding painting apparatus, and is heated by a hot plate to soften the painting film. Facing the cavity of the female mold, the painted film is brought into close contact with the inner surface of the cavity, the hot plate is retracted from the position between the male mold and the female mold, the male mold and the female mold are fastened, and the cavity is closed. In the simultaneous injection molding and painting method of injecting a molten resin into a molded product and adhering the painted film to the surface of the molded product, the painted film is spread from a supply unit to a position facing the cavity of the female mold in a strip shape. After holding the painted film in contact with the female parting surface, fix the painted film at a position closer to the painted film supply unit than the female parting surface and in the film feeding direction. With cutting in a direction which forms a straight,
The hot platen, which has been placed at a position different from the space area between the male and female molds, is moved between the male and female molds to a position facing the painted film that is fixed to the female parting surface And heating and softening the painted film with the hot plate in a state of floating from the surface of the hot plate.

[0012] In the injection molding simultaneous painting method according to claim 2,
The film is held in contact with the female parting surface by fitting a film holding frame through a painting film into a fitting groove provided in a peripheral portion of the female parting surface.

According to a third aspect of the present invention, there is provided a simultaneous painting method for injection molding.
After molding the molded product by injecting the molten resin into the cavity, the film holding frame fitted in the fitting groove of the female parting surface faces the fitting groove on the male parting surface. Move into the fitting groove provided
It is characterized in that the fixing of the picture film to the female mold is released, the male mold and the female mold are opened, and the molded product is taken out.

According to a fourth aspect of the present invention, there is provided a simultaneous painting method for injection molding.
After extending the painting film from the supply section to a position facing the female cavity, the painting film is gripped by the film holding frame provided on the downstream side in the female painting film feeding direction, and then the painting film is moved to the painting film. The painting film is tensioned by applying tension from the supply section side, and thereafter, the painting film is fixed to the female parting surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall schematic configuration of an example of an apparatus for performing a method for simultaneously painting a molded article to be injection-molded. In the figure, reference numeral 1 denotes a male mold of a molding apparatus, and the male mold 1 is fixed to a fixed platen 3. The male mold 1 is arranged to face the female mold 2. An injection nozzle 5 is provided in the male mold 1 so as to communicate with the injection gate 4. The female die 2 is fixed to a ram 7 via a movable plate 6. The female mold 2 is moved forward and backward with respect to the male mold 1 by the reciprocating operation of the ram 7. further,
The female mold 2 has an exhaust hole 8 through which air in the female mold 2 is exhausted by a vacuum pump (not shown). The male part 1 has a rectangular fitting groove 1 on the parting surface.
a, and a rectangular fitting groove 2b is formed on the parting surface of the female mold 2 so as to face the fitting groove 1a.

A hot platen 9 is arranged at a position separated by a predetermined distance from the outer surface of the male mold 1 and the female mold 2 (a space area between both molds). The position where the hot platen 9 is arranged is hereinafter referred to as a standby position. On the other hand, the position where the male mold 1 and the female mold 2 are arranged to face each other and the hot platen 9 is moved between them is hereinafter referred to as a forward position. Hot platen 9
Can be moved between the standby position and the forward position by driving means (not shown).

X is a painting film. The painting film X is pulled out from the roll R in the direction of the arrow by the chuck devices 34, 34 and sent to a position facing the female mold 2 as described later. .

2 and 3 show details of the hot platen 9. FIG. Hot platen 9
Has a laminated structure in which a heating plate 10, a liner plate 11, a heater panel 12, and an insulating plate 13 are arranged in this order. The heating plate 10 heats the painted film X as described later. A rectangular holding frame 14 is fixed to the periphery of the front side surface of the heating plate 10. The hot platen 9 includes a solenoid 16
Is attached to the support member 15 so as to be moved. By the operation of the solenoid 16, the hot platen 9 is moved in a direction perpendicular to the surface of the film X. The solenoid 16 moves the hot platen 9 forward and backward to the female mold 2 as described later.

The heating plate 10 of the hot platen 9 is made of a metal having excellent heat conductivity. The heating plate 10 is attached to the peripheral wall 14a of the holding frame 14.
A large number of small air blowing holes 17 are arranged at a predetermined pitch interval in a region surrounded by. These air blowing holes 17 penetrate from the front side to the rear side of the heating plate 10. As shown in FIG. 5, a concave portion 14b is formed by the heating plate 10 and the peripheral wall 14a of the holding frame 14. When a ceramic layer is formed on the front side surface of the heating plate 10, the radiation heat efficiency is improved. The liner plate 11 disposed behind the heating plate 10 is made of a metal plate having high heat transfer characteristics. The liner plate 11 has a surface that contacts the rear side of the heating plate 10. The surface is provided with a groove 18 through which compressed air is sent to the air outlet 17. A vent hole 19 is provided at the center of the liner plate 11. The ventilation holes 19 pass through the liner plate 11. The ventilation hole 19 passes through the center of the heater panel 12 and the center of the insulating plate 13. The ventilation hole 19 is opened to the rear side surface of the insulating plate 13, and the opening of the ventilation hole 19 is connected to the air hose 20. The air hose 20 can be connected to a low-pressure compressor 22 or a high-pressure compressor 23 through a three-way switching valve 21.

The heater panel 12 has a plurality of heating wires 24. These heating wires are connected to a power supply line (not shown). The insulating plate 13 has a function of effectively transmitting the heat generated by the heating wire 24 toward the heating plate 10.

As shown in FIGS. 3 and 4 (enlarged view of a portion indicated by reference numeral 4 in FIG. 2), a sealing ring fitting groove 25 is formed along the peripheral wall 14a of the holding frame 14. When the sealing ring 26 is fitted into the groove 25, air leakage is prevented. Further, during the vacuum forming operation, deviation of the painted film from a predetermined position is prevented.

As shown in FIG. 1, at a standby position of the hot platen 9, a film pressing means 31 is provided. The film holding means 31 has a rectangular film holding frame 32 (shown in FIG. 6). Holding frame 32
Operates to hold the painting film X in a completely non-contact state, as described later. A cutter device 35 (FIG. 10) is provided immediately upstream of the forming device with respect to the feeding direction of the picture film X. The cutter device 35 cuts the picture film X pulled to a predetermined position immediately upstream of the forming device. The cutter device 35 is driven by an air cylinder 35a.

At first, the picture film X has a band shape in which a specific symbol Y (see FIG. 3) is printed at a predetermined interval. This painting film X is wound in a roll R shape and held in the supply holding device S (FIG. 1). In one embodiment of the “laminate film” for the painted film X, a product in which a pattern is printed on a thermoplastic resin such as an acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS), or polyvinyl chloride can be used. .

As an example of the transfer printing film,
A laminate in which a transfer printing layer composed of a transfer protection layer, a design layer and an adhesive layer is formed on a release substrate such as biaxially stretched polyethylene terephthalate resin or propylene can be used.

From the viewpoint of the three-dimensional contour following characteristics (molding characteristics) required in the simultaneous injection molding painting method, and from the viewpoint of the durability of the design surface (abrasion resistance, etc.), the "dilution" is applied to the painted film substrate or the transfer layer. A resin which becomes a non-tacky thermoplastic solid even in a non-crosslinked state after drying of the medium "can be used. Such resins are described in JP-A-61-69487 and JP-A-60-161121. Examples of the base material of the laminate film or the transparent protective layer of the transfer film include a glass transition temperature of 0 ° C to 250 ° C.
A material obtained by adding a polymerizable cross-linking radical such as an acryl group and a methacryl group to a non-adhesive thermoplastic copolymer such as an acrylic resin at ℃.

The material before the polymerization or before the crosslinking reaction is transferred or laminated on the surface of the injection molded resin article. Thereafter, the resulting laminate is cured by a crosslinking reaction using ultraviolet light or an electron beam.

Next, with reference to FIGS. 7 to 14, a method for simultaneous painting by injection molding will be described. First, from the state of FIG. 1, the chuck device 34 grasps the end of the painting film X, and
As shown in (1), the female mold 2 is pulled between the male mold 1 and the female mold 2, and the entire cavity 2a of the female mold 2 is covered with the picture film X. Further, the film holding frame 32 is moved from the standby position shown in FIG.
To the position shown in FIG.
Thereafter, the position of the holding frame 32 is adjusted so as to coincide with the fitting groove 2b on the facing surface of the female die 2. The fitting groove 2b is arranged so as to surround the surface of the cavity 2a.

Next, as shown in FIG. 8, the film holding frame 32 is pushed into the fitting groove 2b with the picture film X interposed therebetween. Thus, the painting film X is brought into contact with the parting surface of the female mold 2.
At this point, it is preferable that the outer surface of the film holding frame 32 be at the same level as the outer surface of the female mold 2 after the fitting. However, as shown in the figure, when the fitting groove 1a is formed on the outer peripheral portion of the male mold 1 and this fitting groove is opposed to the fitting groove 2b of the female mold 2, the outer surface of the film holding frame 32 is female mold. It need not be at the same level as the outer surface of the second.
Rather, it is preferable that the film holding frame 32 protrudes and the peripheral wall 14a of the holding frame 14 is easily pressed as described later. FIG. 9 shows the front surface of the female mold 2 as viewed from the left side of FIG. As shown in the figure, a film holding frame 32 has a connecting portion 32 connected to its driving source on its side.
a.

Next, as shown in FIG. 10, the picture film X is cut by the cutter device 35 immediately upstream of the molding device by operating the air cylinder 35a. Then, the hot platen 9 at the standby position is moved to the front surface of the female die 2. Next, the painting film X is pushed into the fitting groove 2b via the film holding frame 32 by the peripheral wall 14a of the holding frame 14 on the hot platen 9. At this stage, the painting film X is brought into contact with the peripheral wall 14 a on the hot platen 9. In this way, a closed heating space is formed, and the painted film X is heated in a non-contact state with the hot platen. After being sufficiently softened, the painted film X is subjected to vacuum suction through the exhaust holes 8 as shown in FIG. At this time, blowing air from the air blowing holes 17 may be used together, if necessary. Thereby, the painted film X is made to conform to the shape of the cavity surface 2a.

Thereafter, as shown in FIG. 12, the hot platen 9 is retracted to the standby position. Next, the female mold 2 and the male mold 1 are fastened to each other. Then, the molten resin is injected from the injection gate 4, and the cavity is filled with the resin.

After the molten resin is cooled and solidified as shown in FIG. 13, the male mold 1 and the female mold 2 are opened, and then the film holding frame 32 is pulled out from the fitting groove 2b of the female mold 2. In this way, the resin molded product fixed to the painting film X is taken out. When the painting film X is a transfer printing film, only the base film is peeled off, and the design is left on the molded product.

In another method of opening the mold, as shown in FIG. 14, after the molten resin is cooled and solidified, the film holding frame 32 is moved from the fitting groove 2b of the female mold 2 to the fitting groove 1a of the male mold 1. Moved into. After the painting film X is released, the mold opening operation shown in FIG. 13 is performed. According to this method, molding of the molded product from the male mold 1 and the female mold 2 becomes easy.

The effect of the above-described embodiment is as follows.
Is directly separated from the upstream side by the cutter device 35 in a state where it is directly fixed on the opposing surface of the female mold, and is heated and softened. The effect of the softening of X is that it does not affect the painted film X on the upstream side. And
A high degree of positional accuracy is easily obtained when the pattern is aligned with the mold. When positioning the pattern and the mold irregularities with high precision, a positioning mark such as a cross is printed on the painting film X, and this is detected by a position sensor such as a photoelectric tube fixed to a molding machine, and the painting film is detected. Stop feeding X.

Although the transfer printing method has been described in the above embodiment, the present invention can also be applied to a laminating method.

In the above embodiment, a panel heater that emits near-infrared rays can be used. In addition to this heater, an electric heater (using a nichrome coil and directly drawing Joule radiation heat such as surface resistance) can be used. A heater that radiates the film X), a ceramic panel that radiates far infrared rays,
Alternatively, dielectric heating can be used. In addition, as an example of the thermal transfer method for the painted film X, infrared radiation, electromagnetic waves, or the like can be directly used. Furthermore, the air can be heated in the closed space to perform the thermal transfer to the picture film X. Of course, both can be used together.

FIGS. 15 to 19 show another embodiment of the present invention. In these figures, the cutter device 35 shown in FIG. 10 is omitted. In this embodiment, the driving method of the film holding frame 32 is improved, and a sliding rod 36 is integrally fixed to the film holding frame 32 as shown in FIGS. The sliding rod 36 includes the female mold 2 and the movable platen 6.
In the direction of operation of the ram 7 and is connected to a reciprocating mechanism (not shown) located behind. As shown in FIG. 15, a film fixing holding frame 38 is provided at the lower part of the female mold 2 adjacent to the parting surface so as to be able to advance and retreat. The holding frame 38 is a plate material parallel to the lower side of the rectangular holding frame 32, and behind both ends thereof,
An operation rod 39 having a gap larger than the width of the film X is fixed, and this operation rod 39 forms an output shaft of a reciprocating drive source 40. On the other hand, on the downstream side of the film roll R supported by the supply holding device S, a pair of feed rolls 42 capable of normal and reverse rotation is provided, and at the time of normal rotation, the painting film X is sent in the direction of the female mold 2, At the time of reverse rotation, the picture film X can be reversely fed toward the roll R.

In this embodiment, the cavity 2 of the female mold 2 is
The exhaust port a is composed of small holes distributed over the entire inner surface as shown by 8a, and the intake air from these small holes 8a is sucked to the outside through the exhaust passage 8. FIG.
As shown in (1), a heat shield plate 43 made of a heat insulating material is provided on the front surface of the heat plate 9 so as to be movable by a driving device 44.

In this embodiment, in order to obtain a state corresponding to the state of FIG. 7 of the previous embodiment, the feed roll 42 is rotated forward and the chuck device 34 is operated in the state of FIG. Is lowered to a position covering the parting surface of the female mold 2 as shown in FIG. As a result, the lower end of the film X is fixed to the holding frame 3 for fixing the film.
Come to the position inside 8. However, in this state, the painting film X is sent a little extra due to inertia,
As shown in FIG. 17, slacks and wrinkles remain. In this state, as shown in FIG. 18, the drive source 40 is operated to retract the film holding frame 38, hold down and fix the leading end of the painting film X, and simultaneously rotate the feed roll 42 in reverse. As a result, tension acts on the film X, and the slack and wrinkles of the film X are removed. Then, slide rod 3
6 is retracted as shown in FIG. 19, whereby the film holding frame 32 is pushed into the fitting groove 2b of the female die 2. Therefore, the painting film X also enters the fitting groove 2b and is fixed at a predetermined position. This state corresponds to the state in FIG.

The subsequent steps are the same as those shown in FIGS. 10 to 14, and the molded article with the simultaneous injection-molded picture is taken out of the mold. In this embodiment, by arranging the heat shield plate 43 so as to face the heating side of the front surface of the heat plate 9 at the standby position shown in FIG. Unnecessary heating of the painting film, the forming device, and the like prevents the painting film from melting, deforming, and causing inconveniences such as fire.

[0040]

According to the first aspect of the present invention, the main part of the painted film is heated while floating from the surface of the hot platen. In addition to improving the quality, the painted film spreads on the cavity surface of the female mold at room temperature before it is hard to deform before heating, so wrinkles, sagging and deformation are less likely to occur on the painted film, and furthermore, the The positioning accuracy of the picture sheet pattern is improved. And since the painting film is cut off from the film supply side while the painting film is fixed to the female mold,
The influence of the molding operation, for example, deformation of the painted film, generation of stress, etc., does not affect the unformed upstream painted sheet.

According to the second aspect of the present invention, it is ensured that the painted film is firmly fixed to the female mold, and deformation or displacement of the painted film hardly occurs during molding or cutting of the painted film.

According to the third aspect of the present invention, it is possible to secure the fixation of the painting film to the female mold, and to easily and quickly release the fixation of the painting film and the molded product when the mold is opened. It is possible to release the formed molded product.

According to the fourth aspect of the present invention, the tension is applied to the painted film after the painted film is sent to the female mold, so that the sagging, wrinkles and deformations caused by the inertia of the feeding of the painted film are removed. The retention in the female mold is ideal.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a cross section of a part of an example of an apparatus for performing a simultaneous injection molding painting method of the present invention.

FIG. 2 is a partial sectional view of a hot plate of the apparatus of FIG.

FIG. 3 is a front view of a hot plate.

FIG. 4 is an enlarged sectional view showing a hot plate and a holding frame.

FIG. 5 is a view showing a hot platen and a film pressing means.

FIG. 6 is a perspective view of a film holding frame used in the present invention.

FIG. 7 shows one stage of operation of the device of FIG.

FIG. 8 is an explanatory diagram of a next operation state of FIG. 7;

FIG. 9 is a left side view of the female mold shown in FIG. 8;

FIG. 10 is an explanatory diagram of the next operation state of FIG. 8;

FIG. 11 is an explanatory diagram of an operation state next to FIG. 10;

FIG. 12 is an explanatory diagram of an operation state next to FIG. 11;

FIG. 13 is an explanatory diagram of the next operation state of FIG. 12;

FIG. 14 is an explanatory diagram of the next operation state of FIG. 13;

FIG. 15 is a configuration diagram of another apparatus for implementing the simultaneous injection molding painting method of the present invention.

FIG. 16 is a perspective view of the female mold shown in FIG. 15;

FIG. 17 is an explanatory view showing one operation stage of the device of FIG. 15;

FIG. 18 is an explanatory view showing a next operation stage of the apparatus of FIG. 15;

FIG. 19 is an explanatory view showing a further operation stage of the apparatus of FIG. 15;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 male mold 1a fitting groove 2 female mold 2a cavity inner surface 2b fitting groove 7 ram 8 exhaust hole 9 heating plate 10 heating plate 14 holding frame 14a holding frame peripheral wall 14b recess 16 solenoid 17 air blowing hole 18 groove 19 air passage 21 , 29 Three-way switching valve 22 Low-pressure air source 23 High-pressure air source 24 Heater wire 32 Film holding frame 34 Chuck 35 Cutter 36 Sliding rod 38 Film holding holding frame 42 Feed roll 43 Heat shield X Painted film

Continued on the front page (72) Inventor Takashi Tarutani 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Takeshi Matano 1-chome, Ichigaya-cho, Shinjuku-ku, Tokyo No. 1-1 Inside Dai Nippon Printing Co., Ltd. (72) Inventor Kazuhisa Kobayashi 1-1-1, Ichigaya Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Hiroyuki Atake Shinjuku, Tokyo 1-1-1 Ichigaya-Kaga-cho, Dai Nippon Printing Co., Ltd. (56) References JP-A-3-222705 (JP, A) JP-A-2-145313 (JP, A) JP-A-61-137716 ( JP, A) JP-A-5-301250 (JP, A) JP-B-4-2418 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (4)

(57) [Claims] 1. A painting film is fed to a position between the opposite male and female molds of the simultaneous injection molding painting apparatus, and the painting film softened by heating with a hot plate is opposed to the cavity of the female mold. The film is brought into close contact with the inner surface of the cavity, and the hot plate is retracted from the position between the male and female molds.
In the injection molding simultaneous painting method in which a male mold and a female mold are fastened to close a cavity, a molten resin is injected into the cavity to form a molded product, and a painted film is adhered to the surface of the molded product. From the female mold cavity to a position facing the cavity of the female mold, and after firmly holding the painting film on the female parting surface, painting is performed at a position closer to the painting film supply unit than the female mold parting surface. A hot platen, which cuts the film in a direction perpendicular to the film feed direction and waits at a position different from the space between the male and female dies, inserts a female plate between the male and female dies. Moving the painting film to a position facing the painting film fixed on the surface of the heating plate, and heating and softening the painting film with the heating plate while floating from the surface of the heating plate. 2. A method for simultaneous painting by injection molding according to claim 1, wherein a film holding frame is fitted through a painting film into a fitting groove provided on a peripheral portion of the female parting surface, thereby providing a picture. A method comprising contacting and securing a film to a female parting surface. 3. A method according to claim 2, wherein the molten resin is injected into the cavity to form a molded product, and then the film is fitted in the fitting groove of the female parting surface. The holding frame is moved into the fitting groove provided on the male molding surface facing the fitting groove to release the fixation of the painting film to the female mold, and the male mold and the female mold are opened and formed. A method characterized by taking out an article. 4. The method for simultaneous painting by injection molding according to claim 1, wherein the painting film is extended from the supply portion to a position facing the cavity of the female mold, and is provided downstream in the feeding direction of the female painting film. Holding the painted film by the film holding frame, and then tensioning the painted film by applying tension to the painted film from the supply unit side,
Thereafter, the painting film is fixed to the female parting surface.