JP2001038783A - In-mold coating molding method and apparatus used therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-mold coating molding method high in processing accuracy and excellent in productivity for injecting a paint in the gap between the surface of the resin molded article molded in a mold and the cavity surface of the mold to cure the same to produce an integrated molded article having a coating film closely bonded to the surface thereof. SOLUTION: In an in-mold coating molding method, a paint is injected in the gap between the surface of the resin molded article molded in molds 51, 52 and the surface of the cavity 53 formed by both molds and cured in the molds 51, 52 to produce an integrated molded article having a coating film closely bonded to the surface thereof. The hydraulic cylinder for the mold clamping driving of a toggle type injection molding machine or the stroke of the ball screw for the mold clamping driving of a toggle type motor-operated injection molding machine is subjected to feedback control by using a mold clamping servo valve 15 or servo motor to control driving according to a preset change pattern of mold opening quantity and that of mold clamping force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a resin by injecting a paint between a surface of a resin molded article molded in a mold and a cavity surface of the mold, and then curing the paint in the mold. TECHNICAL FIELD The present invention relates to an in-mold coating forming method and a forming apparatus for obtaining an integrally molded product in which a coating film adheres to the surface of a product.

[0002]

2. Description of the Related Art In order to improve the quality of resin molded products used for automobiles, home appliances, building materials, and the like by adding added value such as decorativeness, and to reduce costs by reducing the number of molding steps, it is necessary to reduce the cost in a mold. After injecting a paint between the surface of the resin molded product molded in step 1 and the cavity surface of the mold, the paint is cured in the mold to produce an integrated molded product in which the coating film adheres to the surface of the resin molded product. An in-mold coating molding method (hereinafter, referred to as "IMC") has been studied. In recent years, this IMC has been subject to severe concerns about environmental issues, and the emission of harmful organic substances from various factories to the atmosphere has been severely restricted.
From the perspective of emphasizing the protection of employees' health, it has also attracted attention as a technology that can replace conventional spray painting.

[0003] At the beginning of development, IMC is exclusively SMC, BMC
And the manufacture of molded products of such thermosetting resins. However, in recent years, Japanese Unexamined Patent Application Publication No.
In the publication, when the surface temperature of the resin is equal to or higher than the curing temperature of the paint, the mold clamping force of the mold is changed, or under the same mold clamping force, the thermosetting paint is injected into the painted surface of the resin port. In addition, the IMC is also applied to the molding of thermoplastic resins, such as a method of opening a mold after the coating material is cured.

[0004]

However, in the case of the thermoplastic resin IMC, the mold temperature conditions are different between the thermoplastic resin IMC and the thermosetting resin IMC. For the reason that the paint to be cured is required to have a curing property that cures at a lower temperature than the paint for the thermosetting resin, the setting of the molding conditions for improving the appearance and the adhesion strength of the coating film is difficult. It is much more difficult than the curable resin IMC.

In addition, the conventional injection molding machine is not designed for the purpose of performing IMC only for the purpose of molding the resin, and the control of the mold clamping force and the position control of the mold are precisely performed. The fact that it is not designed to operate at high speed is also one of the reasons for making IMC of a thermoplastic resin difficult. In other words, when the position of the mold and the mold clamping force are not determined at high speed, the paint cannot be sufficiently spread into the mold cavity after the paint is injected, or a part of the injected paint partially cures. For example, it was extremely difficult to obtain a uniform coating film upon starting. From these facts, Japanese Patent Application Laid-Open No. Hei 5-30
Even when the method disclosed in Japanese Patent No. 1251 is used, it is possible to control the curing condition of the paint as long as the conventional injection molding machine having a slow operation of controlling the clamping pressure and the mold position is used. It was difficult and not always productive.

[0006] In order to improve such a situation, for example, Japanese Patent Application Laid-Open No. 6-254886 discloses an attempt to optimize the IMC molding conditions by giving a predetermined amount of mold opening to a mold. However, in this case, the IMC device is provided with a mold driving means opposed to the normal mold opening / closing drive means, and is stopped at a predetermined mold opening position as a result of interaction. Because of the mechanism, the control system is complicated and the control response is not always high, and there is a problem that the operation time to a predetermined stop position cannot be sufficiently reduced.

Further, since the mold clamping force control for controlling the pressure and the mold opening control for controlling the position are performed by different control systems, the mold clamping force and the mold opening are alternately and continuously controlled. However, there is also a disadvantage that it is not suitable for in-mold coating molding which is required. As a consequence of these problems, the production yield of obtaining a resin molded product on which a coating film having good properties is formed has not been high.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to control the mold clamping force and the mold opening amount of a mold by continuously changing molding conditions. In addition, by enabling high-precision and high-speed execution, the choice of molding conditions for the thermoplastic resin IMC has been greatly expanded, and an integrated molded product with excellent appearance and adhesion strength of the coating film has been greatly enhanced. It is an object of the present invention to provide an in-mold coating forming method and an in-mold coating forming apparatus which enable production.

[0009]

That is, according to the present invention,
After injecting paint between the surface of the resin molded product molded in the mold and the cavity surface of the mold, the paint is cured in the mold, and a coating film is formed on the surface of the resin molded product. This is a method of forming an in-mold coating for producing a coherent integral molded product, wherein a stroke of a hydraulic cylinder for a mold-clamping drive of a toggle-type injection molding machine or a ball screw for a mold-clamping drive of a toggle-type electric injection molding machine is respectively clamped. A method for forming a coating in a mold, characterized in that drive control is performed with a preset pattern of a change in a mold opening amount and a change pattern of a mold clamping force by performing a feedback control using a servo valve or a servo motor for use. Is done.

[0010] In the above-described method of forming a coating in a mold according to the present invention, the pressure in the mold of the paint injected into the mold is set in advance by performing feedback control using a servo valve or a servomotor for mold clamping. It is preferable to control the drive in accordance with the changed pattern. In addition, by sending and receiving each command signal of the start of the measurement of the paint injection machine, the start of the mold opening of the injection molding machine, the start of the injection of the paint injection machine, and the start of the re-clamping of the injection molding machine, the injection molding machine and the paint injection machine are exchanged. It is also preferable to operate such that the above operations are linked. Furthermore, the thickness of the paint and the curing conditions are controlled by increasing the pressure in the mold of the paint injected into the mold immediately after the injection of the paint and changing the pressure gradually over time so as to gradually decrease thereafter. Is also preferred.

Further, according to the present invention, in performing the above-mentioned method for coating in a mold, after paint is injected between a surface of a resin molded product molded in the mold and a cavity surface of the mold. An in-mold coating molding apparatus for curing the paint in the mold to produce an integral molded article having a coating film adhered to the surface of the resin molded article, wherein the mold-clamping drive of a toggle injection molding machine is provided. A mold clamping servo valve for controlling the flow rate and pressure of hydraulic oil supplied to the hydraulic cylinder, a stroke sensor for detecting a stroke of the hydraulic cylinder, and a mold opening sensor for detecting a mold opening of the mold. A mold clamping force sensor for detecting a mold clamping force of the mold, a paint pressure sensor for detecting an in-mold pressure of the paint injected into the mold, and a paint injector for injecting the paint. With the change in the mold opening of the mold. Setting unit for setting and inputting the change pattern of the mold and the clamping force and the change pattern of the in-mold pressure of the paint, and the paint injector is driven by receiving a command signal from the mold-clamping condition setting unit. The injector control unit to be controlled, the correlation between the stroke of the hydraulic cylinder detected by the stroke sensor and the mold opening detected by the mold opening sensor, and the stroke of the hydraulic cylinder detected by the stroke sensor. The correlation with the mold clamping force detected by the mold clamping force sensor is stored in advance, and the change pattern of the mold opening amount and the change pattern of the mold clamping force of the mold set in the mold clamping condition setting unit. A change pattern storage unit for converting each of the pressure cylinders into a change pattern of the stroke of the hydraulic cylinder, a change pattern of the stroke of the hydraulic cylinder, and a change of the in-mold pressure of the paint. According to the pattern, mold coating forming apparatus characterized by comprising a mold clamping control unit to perform the feedback control to the servo valve for the mold clamping, are provided.

[0012] The coating molding apparatus in a mold comprises a toggle type electric injection molding machine instead of a toggle type injection molding machine, a ball screw for mold clamping drive instead of a hydraulic cylinder for mold clamping drive, and a servo valve for mold clamping. Alternatively, a configuration using a servo motor may be used.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. However, it goes without saying that the present invention is not limited to these embodiments. FIG. 1 is an explanatory diagram showing an overall configuration diagram of an in-mold coating forming apparatus (hereinafter, referred to as an "IMC apparatus") according to the present invention. The IMC device 100 uses a toggle type injection molding machine, and is roughly composed of a mold clamping device 10, an injection device 20, a control device 30, and a mold device 50.

The mold clamping device 10 includes a fixed platen 11 and a movable platen 12 on which a mold device 50 is mounted.
4 and a mold-clamping drive hydraulic cylinder (hereinafter, referred to as
This is referred to as a "clamp cylinder". The movable platen 12 moved forward and backward by 13) moves back and forth with respect to the fixed platen 11, thereby opening and closing the mold device 50.

In the toggle type injection molding machine, a large stroke can be obtained while driving the mold clamping cylinder 13 with a relatively low hydraulic pressure. Then, the stroke amount is converted into a smaller stroke amount by the mold clamping device 10 and also converted into a larger pressure.

Therefore, as compared with the conventional direct pressure type injection molding machine in which the mold is directly driven by the hydraulic cylinder, the toggle type injection molding machine is driven by the mold clamping cylinder 13 which has excellent driving characteristics, especially high speed driving characteristics. Is performed, and the position controllability of the mold device 50 is made extremely high by the so-called boosting mechanism of the mold clamping device 10, and a sufficiently strong mold clamping force is obtained. And
These excellent driving characteristics allow the paint to be uniformly distributed in the mold cavity after the paint is injected into the mold cavity in the IMC, as well as to enable uniform curing of the paint and formation of a coating film, as described later.

In the injection device 20, a screw 21 having a spiral flight portion is rotatably driven by a hydraulic motor 23 along the inner peripheral surface of a cylindrical barrel 22 so as to be able to move forward and backward freely. It is arranged. With the rotation of the screw 21, the resin pellets supplied into the hopper 25 are sent to the front of the screw 21, and are heated by a heater (not shown) attached to the outer peripheral surface of the barrel 22 during this time. At the same time, the resin pellets are melted by receiving the kneading action by the rotation of the screw 21.

When the amount of molten resin sent to the front of the screw 21 reaches a predetermined amount, the hydraulic motor 23
The rotation of the screw 2 is stopped, and the injection cylinder 24 is driven to move the screw 21 forward.
1 The molten resin stored in front is injected into the mold cavity 53 of the mold apparatus 50 via the nozzle 26.

The mold apparatus 50 includes a fixed mold 51 attached to the fixed board 11 and a movable mold 52 attached to the movable board 12. And a paint pressure sensor 54 for detecting the pressure of the paint injected into the mold cavity 53.

Next, the configuration of the control device 30 will be described. As shown in FIG. 1, the control device 30 includes a mold clamping device 1.
0 and the operation of the injection device 20 are linked, and the control device 3
Molding device controller 3 that controls the entire system
1 and an injection control unit 38 that controls the operation of the injection device 20. These two control units 31 and 38 have the same control function as the control unit in a normal injection molding machine.

On the other hand, as a control unit having a control function unique to the IMC device 100 of the present invention, a molding condition data signal (refers to a change pattern of molding conditions) from the mold clamping condition setting unit 32.
The same applies hereinafter. ), And a mold clamping control unit 33 that controls the operation of the mold clamping device 10 by receiving a molding condition data signal from the mold clamping condition setting unit 32 and controls the operation of the paint injecting machine 55. The mold opening amounts of the molds 51 and 52 sent from the mold clamping condition setting unit 32 (hereinafter, referred to as “mold opening amounts”).
And a molding condition data signal of a mold clamping force (hereinafter, referred to as “mold clamping force”) of the molds 51 and 52, and converts this into a molding condition data signal of a stroke of the mold clamping cylinder 13, and the mold clamping control unit. And a change pattern storage section 34 for sending the change pattern to the change pattern storage section 33.

Here, in the mold clamping condition setting section 32, the opening / closing speed of the mold clamping device 10, the operation timing, the mold opening amount, the mold clamping force, the injection amount of the paint injector 55, the injection speed, the injection timing, the injection pressure, and Each molding condition of the paint pressure in the mold cavity 53 is set. Then, the molding condition data signal is sent from the mold clamping condition setting unit 32 to the injection machine control unit 35 for the molding conditions relating to the injection amount, the injection speed, the injection timing, and the injection pressure of the paint injecting machine 55. As for the molding conditions relating to the opening / closing speed of the device 10, the operation timing, and the paint pressure in the mold cavity 53, the molding condition data signal is sent to the mold clamping control unit 33. As for the molding conditions relating to the mold opening amount and the mold clamping force, the molding condition data signal is sent to the change pattern storage unit 34.

By the way, in the change pattern storage unit 34,
Prior to the control, it is necessary to previously store the correlation between the stroke of the mold clamping cylinder 13 and the mold opening amount and the correlation between the stroke of the mold clamping cylinder 13 and the mold clamping force.

For this reason, after the mold device 50 is mounted on the fixed platen 11 and the movable platen 12, the die height adjustment according to the mold thickness (die height) of the mold device 50 is carried out by the same procedure as in ordinary injection molding. In a state where the mold clamping force adjustment is completed, the change pattern storage unit that continuously receives the respective detection signals of the stroke sensor 16, the mold opening amount sensor 17, and the mold clamping force sensor 18 while opening and closing the mold device 50. 3
In step 4, the correlation between the stroke of the mold clamping cylinder 13 and the mold opening amount and the correlation between the stroke of the mold clamping cylinder 13 and the mold clamping force are calculated and stored.

Next, the operation of the IMC device 100 when performing the IMC using the IMC device 100 having the control device 30 configured as described above will be described with reference to a specific example.

First, according to the control signal transmitted from the mold clamping control section 33 and the feedback control by the mold clamping servo valve 15, the mold clamping cylinder is set in accordance with the mold closing speed pattern set in the mold clamping condition setting section 32. By 13
The movable mold 52 is advanced from the mold opening limit position, and the fixed mold 5 is moved.
Touch 1 Subsequently, while performing a feedback control by the control signal transmitted from the mold clamping control unit 33 and the servo valve 15 for mold clamping, a molding condition data signal of the mold clamping force set in the mold clamping condition setting unit 32 (the mold clamping force). According to the change pattern, the movable mold 52 is further advanced by the mold clamping cylinder 13 to extend the tie rod 14 and a predetermined mold clamping force is applied to the mold apparatus 50.

At a predetermined operation timing during the operation of the mold clamping device 10, the injection cylinder 24 controls the screw 21 while controlling the opening of the injection servo valve 27 by a control signal transmitted from the injection control unit 38. When the resin is advanced, the molten resin stored in front of the screw 21 is injected into the mold cavity 53 via the nozzle 26 to form a resin molded product. The operation of the mold clamping device 10 and the operation of the injection device 20 are interlocked with each other by the molding device control section 31 so as to exchange operation timing signals.

Next, the movable mold 5 is moved by the mold clamping cylinder 13.
2 is retracted, and the mold opening amount set in the mold clamping condition setting unit 32 is given while performing feedback control by the control signal transmitted from the mold clamping control unit 33 and the mold clamping servo valve 15, and the resin molded product is After a gap is provided between the front surface and the surface of the mold cavity 53, the injection machine control unit 35 is controlled according to the injection amount, injection speed, injection timing, and injection pressure of the paint injection machine 55 set in the mold clamping condition setting unit 32. The paint injecting machine 55 is driven by the control signal transmitted from the above, and the paint is injected into the mold cavity 53.

Subsequently, the movable mold 52 is moved by the mold clamping cylinder 13 while the control signal transmitted from the mold clamping control section 33 and the feedback control by the mold clamping servo valve 15 are performed.
Is advanced again to execute the molding condition data signal (mold opening change pattern) and the molding condition data signal (paint pressure pattern) of the mold opening set in the mold clamping condition setting unit 32. In this way, the injected paint can be spread over the entire surface of the resin molded product, and at the same time, optimum molding conditions can be given to the appearance and adhesion strength of the coating film.

In order to stabilize the appearance and adhesion strength of the coating film, it is desirable to perform feedback control according to a predetermined coating pressure pattern using the coating pressure sensor 54 as described above. In particular, as shown in Example 1 to be described later, when the pressure in the mold after paint injection is changed in multiple stages over time so as to be high immediately after the injection of the paint and to gradually decrease thereafter, the paint becomes more uniform. In addition, there is an advantage that it is possible to spread the inside of the mold, and it is also possible to use a highly viscous paint.

By the way, the paint pressure sensor 5 is
When it is difficult to dispose 4, the mold clamping force pattern is set instead of the paint pressure pattern, and the feedback control according to the mold clamping force pattern can be performed.

Then, while performing a feedback control by the control signal transmitted from the mold clamping control unit 33 and the mold clamping servo valve 15, the mold is set in accordance with the operation timing and the mold opening speed pattern set in the mold clamping condition setting unit 32. The movable mold 52 is retracted by the tightening cylinder 13 to the mold opening limit position, and the integrally molded product is taken out of the mold apparatus 50. Thus, one molding cycle is completed.

As described above, in the present invention, the mold closing speed pattern, the mold clamping force pattern, the mold opening amount pattern, and the mold opening speed pattern set in the mold clamping condition setting unit 32 are all determined by the stroke pattern of the mold clamping cylinder. Since unification and feedback control are performed, the control target is always the stroke pattern of the mold clamping cylinder even under molding conditions in which the mold clamping force and the mold opening amount are alternately repeated.

Therefore, since the control is performed continuously without changing the control object, a high response which can sufficiently cope with a steep change pattern can be exhibited. That is, by applying a simplified control system to the inherent features of the toggle-type injection molding machine such as high-speed and high-precision driving of the mold, the characteristics can be maximized. In this way, it is possible to drive and control the process from the injection of the paint to the curing of the equipment with high speed and precision, to stabilize the properties of the coating film, to improve the product yield and shorten the manufacturing time, and to improve the productivity. Is improved.

In the case where the IMC and the IMC device of the present invention are used, any of the shear edge type and the flat push type can be used as the molds 51 and 52.

In injection molding of a thermoplastic resin, a flat-press mold is often used. In this case, a part of the mold clamping force generated by the injection molding machine is a force for compressing the resin molded product and the paint. And a part of it will be received on the parting surface. Further, the mold clamping force changes with time based on a temperature change of the resin molded product or the paint in the mold or a volume change due to curing shrinkage. Therefore, when a flat-pressing mold is used, controlling the compression force between the resin molded product and the paint cannot be achieved only by controlling the mold clamping force.

However, as in the present invention, by disposing a paint pressure sensor in the mold and performing feedback control in accordance with a predetermined paint pressure pattern, the state of the coating inside the mold may vary from shot to shot. Even in such a case, the molding conditions can be controlled so that a stable appearance and adhesion strength of the coating film can be obtained.

On the other hand, shear-edge molds have been widely used in SMC and BMC. In this case, almost all of the mold clamping force generated by the injection molding machine is replaced by the force for compressing the resin molded product and the paint (= paint pressure). It is possible to form a coating film having.

Although the above-described IMC device 100 uses a toggle injection molding machine, a toggle type electric injection molding machine can be used instead of the toggle type injection molding machine. In this case, a mold-clamping drive ball screw may be used instead of the mold-clamping cylinder, and a mold-clamping servomotor may be used instead of the mold-clamping servo valve. Thus, the IM of the present invention
The method of use and the structure of the CMC device are not limited to the above description, and the CMC device and the IMC device can be operated differently according to the purpose of molding. These operations will be described in an embodiment described later.

[0040]

(Embodiment 1) IMC device 100 shown in FIG.
FIG. 2 is a flowchart showing a molding procedure and a mold clamping / mold opening sequence in the first embodiment described below.
Shown in Using a shear-edge type mold that can obtain a box-shaped product with a length of 300 mm, a width of 210 mm and a depth of 50 mm,
First, nylon 6 (Ube Nylon 1013B, manufactured by Ube Industries, Ltd.) was injection molded by applying a mold clamping force of 350 t.
At this time, the resin temperature was 250 ° C., and the mold temperature was 130 ° C.

The cooling time for this resin molding was 30 seconds, and then the mold was opened by about 0.5 mm. Then, after maintaining the opened state for 10 seconds, a paint having good adhesion to nylon 6 is applied to the space between the resin molded product and the mold cavity surface.
cc was injected. The injection time of this paint was 2 seconds. After completion of the injection of the coating material, the mold was clamped after a lapse of 3 seconds, and the mold clamping force was set to 100 t and held for 1 second. At this time, the time required for the pressure increase (increase in the mold clamping force) was about 1.0 second. Thereafter, 2 clamping force as paint pressure sensor is 30kg / cm ² of the set pressure for 50 seconds, and more paint pressure sensor as a third clamping configuration as the second clamping
A mold clamping force of 0 kg / cm ² was applied for 50 seconds.

A film having a thickness of about 100 μm was formed on the entire surface of the integrated molded product taken out. As in Example 1, when the pressure in the mold after paint injection is changed over time so as to be high immediately after injection of paint and gradually decrease thereafter,
It is considered that the paint can be more evenly distributed in the mold. In addition, it is easily presumed that a highly viscous paint can be used, and the effect of expanding the choice of usable paints can be obtained.

The adhesion of the integrally molded article to the coating film was evaluated by a cross-cut cellophane tape test described in JIS K-5400 (General paint test method). as a result,
No peeling was observed at one of the 100 grids, confirming that good adhesion was obtained.

(Embodiment 2) The IMC device 10 shown in FIG.
FIG. 3 shows a flowchart and a mold clamping / mold opening sequence in the case of performing the molding of Example 2 described below using 0. Height 300mm, width 210mm, depth 50mm
First, heat-resistant ABS resin (MX40, manufactured by Ube Sicon Co., Ltd.) was injection-molded by applying a mold clamping force of 350 t using a shear-edge type mold capable of obtaining a box-shaped product. At this time, the resin temperature was 250 ° C., and the mold temperature was 90 ° C.

The cooling time for this resin molding was 30 seconds, and then the mold was opened 1.0 mm. 13 cc of a paint having good adhesion to the ABS resin was injected into an open space between the resin molded product and the mold cavity surface. The injection time of this paint was 2 seconds. After completion of the injection of the paint, the mold was quickly closed. At this time, the time required for increasing the mold clamping force was about 1.5 seconds. The mold clamping force was set to only one step, and the paint pressure sensor showed a set pressure of 30 kg / cm ² , and the mold clamping force was set to 1 step.
It took 20 seconds.

The molded article taken out has a thickness of about 100
A coating film of μm was formed, and the uniformity of the thickness of the coating film was not inferior to that of Example 1. Therefore, it was found that it was not necessary to apply the mold clamping force in multiple stages depending on the type of the paint. Also, as in the first embodiment, JIS K
As a result of evaluating the adhesion of the coating film by the cross-cut cellophane tape test described in -5400 (Coating general test method), no peeling was observed at one place in 100 cross-cuts, and high adhesion was obtained. Was confirmed.

(Embodiment 3) The IMC device 10 shown in FIG.
FIG. 4 shows a flowchart and a mold clamping / mold opening sequence in the case of performing the molding of the third embodiment described below by using 0. 320m length imitating a motorcycle side cover
m, 180 mm wide, using a flat-press mold that can obtain a roughly triangular product.
S resin (MX40, manufactured by Ube Sicon) was injection molded. Here, a rib for preventing the paint from leaking is provided on the entire periphery of the mold, and a gate for resin molding is provided on the surface opposite to the paint injection surface. The resin temperature during shaping is 25
The temperature was 0 ° C. and the mold temperature was 90 ° C.

The cooling time for this resin molding was 30 seconds, and then the mold was opened 1.0 mm. 4 cc of a paint having good adhesion to the ABS resin was injected into an open space between the resin molded product and the mold cavity surface. The injection time of this paint was 1 second. After completion of the injection of the paint, the mold was quickly closed. At this time, the time required for increasing the mold clamping force was about 0.8 seconds. The mold clamping force was only one step, and the mold clamping force was applied for 120 seconds so that the paint pressure sensor showed a set pressure of 30 kg / cm ² .

The molded article taken out has a thickness of about 100
A coating film of μm was formed, and the adhesion of the coating film in the integrally molded product was evaluated in the same manner as in Examples 1 and 2 described above. As a result, no peeling was observed at one place on 100 crosses. It was confirmed that high adhesion was obtained.
As shown in the results of Example 3, it was confirmed that the IMC of a thermoplastic resin using a flat-press mold can also be satisfactorily performed by using feedback control by a paint pressure sensor.

(Embodiment 4) The IMC device 10 shown in FIG.
FIG. 5 shows a flow chart and a mold clamping / mold opening sequence in the case of performing the molding of the fourth embodiment described below using 0. 320m length imitating a motorcycle side cover
m, 180 mm wide, using a flat-press mold that can obtain a roughly triangular product.
S resin (MX40, manufactured by Ube Sicon) was injection molded. Here, a rib for preventing the paint from leaking is provided on the entire periphery of the mold, and a gate for resin molding is provided on the surface opposite to the paint injection surface. The resin temperature during molding is 25
The temperature was 0 ° C. and the mold temperature was 90 ° C.

The cooling time for this resin molding was 30 seconds, and then the mold was opened by 1.0 mm. 4 cc of a paint having good adhesion to the ABS resin was injected into an open space between the resin molded product and the mold cavity surface. The injection time of this paint was 1 second. After completion of the injection of the paint, the mold was quickly closed. At this time, the time required for increasing the mold clamping force was about 0.6 seconds. The mold clamping force was only one step, and a mold clamping force of 1 t was applied for 120 seconds.

The molded article taken out has a thickness of about 100
A coating film of μm is formed, and the adhesion of the coating film in the integrally molded product is evaluated in the same manner as in Examples 1 to 3 described above. As a result, no peeling at one place is observed on 100 crosses. , High adhesion was obtained.

As in the fourth embodiment, when a mold having a structure that does not leak paint is used without using a paint pressure sensor,
It was confirmed that a coating film excellent in uniformity and adhesion was sufficiently obtained only by controlling the mold clamping force.

(Embodiment 5) IMC device 10 shown in FIG.
FIG. 6 shows a flow chart and a mold closing / mold opening sequence in the case where the fifth embodiment described below is performed using 0. 320mm length, 1 width imitating the side cover of a motorcycle
First, using a flat-pressing mold capable of obtaining a product having a substantially triangular shape of 80 mm, a heat-resistant ABS resin (MX40, manufactured by Ube Sycon Co., Ltd.) was injection-molded by applying a mold clamping force of 300 t.
Here, a rib for preventing paint from leaking is provided on the entire periphery of the mold, and a gate for resin molding is provided on the surface opposite to the paint injection surface. The resin temperature during molding is 250 ° C,
The mold temperature was 90 ° C.

A cooling time of 30 seconds was taken for the resin molding, and a paint having good adhesion to the ABS resin was applied under a high mold clamping force.
4 cc was injected at a pressure of 0 kg / cm ² . The injection time of this paint was 1 second. Ten seconds after the completion of the paint injection, the mold clamping force was lowered. The mold clamping force for curing the paint is only one step, and the paint pressure sensor indicates the set pressure of 30 kg / cm ² .
A mold clamping force was applied for 120 seconds.

The molded article taken out has a thickness of about 100
A μm coating film was formed, and the adhesion between the molded product and the coating film was confirmed to be high by a cross-cut cellophane tape test described in JIS K-5400 (General Paint Test Method). It was confirmed that a swell called a hump was slightly generated on the side surface.

As is apparent from a comparison between the above-described Examples 1 to 4 and Example 5, after the resin is molded and before the paint is injected, the mold is opened and a predetermined distance is set in the mold cavity. It is understood that the most preferable method is to adopt a method of forming a gap, and injecting the paint into the gap, and then sharply applying a mold clamping force to spread the paint to the surface of the resin molded product. However, even when the paint is injected without opening the mold after the resin is formed as in the fifth embodiment, the mold is generated by controlling the mold clamping force to a good and constant value with the mold clamping servo valve. The degree of hump can be kept extremely small.

[0058]

As described above, according to the in-mold coating forming method and the in-mold coating forming apparatus of the present invention, the mold position and the clamping force are all integrated into the stroke pattern of the clamping cylinder and fed back. Since control is performed, the control target does not change, and continuous control is possible. Further, by using a toggle injection molding machine, it is possible to control the mold position at high speed and precisely. As a result, the control system can be simplified, and an excellent effect of obtaining high responsiveness which can sufficiently cope with a steep change pattern can be obtained. In addition, by performing feedback control according to a predetermined paint pressure pattern as necessary, it is easy to obtain a stable coating film appearance and adhesion strength even if there is a change in the state of the coating inside the mold for each shot. Become. Furthermore, in the case of the shear-edge type mold that has been frequently used in the conventional SMC and BMC, it is possible to obtain a sufficiently uniform and excellently adhered coating film integrated product only by feedback control of the clamping force. . In general, the present invention has a remarkable effect of improving productivity and realizing cost reduction, and contributing to improvement and maintenance of product quality, particularly in the case of in-mold coating molding of a thermoplastic resin.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an in-mold coating forming apparatus according to an embodiment of the present invention.

FIG. 2 is a flow chart and a mold clamping / mold opening sequence in the case where the molding described in Example 1 is performed using the in-mold coating molding apparatus shown in FIG.

FIG. 3 is a flowchart and a sequence of mold clamping / mold opening in the case where the molding described in Example 2 is performed using the in-mold coating molding apparatus shown in FIG.

FIG. 4 is a flowchart and a sequence of mold clamping / mold opening in the case where the molding described in Embodiment 3 is performed using the in-mold coating molding apparatus shown in FIG.

FIG. 5 is a flowchart and a sequence of mold clamping / mold opening when the molding described in Embodiment 4 is performed using the in-mold coating molding apparatus shown in FIG.

FIG. 6 is a flow chart and a mold clamping / mold opening sequence in the case where the molding described in Example 5 is performed using the in-mold coating molding apparatus shown in FIG.

[Explanation of symbols]

10: mold clamping device, 11: fixed plate, 12: movable plate, 13 ...
Mold clamping cylinder, 14 Tie rod, 15 Mold clamping servo valve, 16 Stroke sensor, 17 Mold opening sensor, 18 Mold clamping force sensor, 20 Injection device, 21 Screw, 22 Barrel, 23 Hydraulic motor, 24 injection cylinder, 25 hopper, 26 nozzle, 27 injection servo valve, 30 control device, 31 molding device control unit,
32 mold closing condition setting unit 33 mold closing control unit 34 change pattern storage unit 35 injection machine control unit 38 injection control unit 50 mold apparatus 51 fixed mold 52 movable Mold, 53: Mold cavity, 54: Paint pressure sensor, 55
... paint pouring machine, 100 ... in-mold coating molding device.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Etsuo Okahara 1980 Yamaguchi Prefecture Ube City, Ogishi-Kogushi-ji, offshore Polymer Research Laboratory Ube Industries, Ltd. (72) Inventor Kazuaki Kobayashi, Ube City, Yamaguchi Prefecture, Ogashi-Kagashi-Okiyama 1980 Ube Industries Co., Ltd.Polymer Research Laboratory (72) Inventor Kenji Yonemochi 878 Nishinomon, Mitsubuchi, Komaki, Aichi Prefecture Dainippon Co., Ltd.Komaki Plant (72) Inventor Yoshiaki Yamamoto Mitsubuchi, Nishi, Komaki, Aichi Prefecture 878 Nomon, inside the Komaki Plant, Dai Nippon Paint Co., Ltd. AP02 AP03 AP11 AR01 AR07 CA11 CB11 CB28 CL32 CL39 CL42 CQ05 4F206 AA49 AD05 AG03 AH17 AH46 AH51 AP024 AP035 AP11 AR014 AR074 JA07 JB 11 JB28 JL02 JM02 JM05 JN25 JN33 JP13 JP17 JQ81 JQ83 JQ88 JT05 JT33 JT35 JT38

Claims (6)

[Claims] 1. After a paint is injected between a surface of a resin molded article molded in a mold and a cavity surface of the mold, the paint is cured in the mold, and the resin molded article is cured. An in-mold coating molding method for producing an integral molded product having a coating film adhered to the surface thereof, comprising: a stroke of a mold clamping drive hydraulic cylinder of a toggle injection molding machine or a mold clamping drive ball screw of a toggle electric injection molding machine. Is controlled by a feedback control using a servo valve or a servo motor for mold clamping, respectively, so that driving control is performed with a preset pattern of a change of a mold opening amount and a change pattern of a mold clamping force. Molding method. 2. The method according to claim 1, wherein the in-mold pressure of the paint injected into the mold is feedback-controlled using the mold-clamping servo valve or the servomotor to perform drive control in a preset change pattern. 2. The method according to claim 1, wherein the in-mold coating is formed. 3. The injection of the paint injection machine is started by receiving and receiving command signals for starting the measurement of the paint injection machine, starting the mold opening of the injection molding machine, starting the injection of the paint injection machine, and starting the re-clamping of the injection molding machine. 3. The method according to claim 1, wherein the operation of the molding machine and the operation of the paint injection machine are interlocked. 4. The method according to claim 1, wherein the pressure in the mold of the paint injected into the mold is changed in multiple stages with time so as to be high immediately after the injection of the paint and to decrease gradually thereafter. The coating molding method in a mold according to any one of claims 1 to 3. 5. After injecting a paint between the surface of the resin molded article molded in the mold and the cavity surface of the mold, the paint is cured in the mold to form the resin molded article. An in-mold coating molding device for producing an integral molded product with a coating film adhered to the surface, the mold clamping controlling the flow rate and pressure of hydraulic oil supplied to a mold clamping drive hydraulic cylinder of a toggle injection molding machine. A servo sensor, a stroke sensor for detecting a stroke of the hydraulic cylinder, a mold opening amount sensor for detecting a mold opening amount of the mold, a mold clamping force sensor for detecting a mold clamping force of the mold, It is equipped with a paint pressure sensor that detects the pressure inside the mold of the paint injected into the mold, and a paint injection machine that injects the paint. Pattern and change pattern of the paint pressure in the mold A mold clamping condition setting unit for setting and inputting each of them; an injection machine control unit for driving and controlling the paint injector in response to a command signal from the mold clamping condition setting unit; and a stroke of the hydraulic cylinder detected by the stroke sensor And the correlation between the mold opening amount detected by the mold opening amount sensor and the correlation between the stroke of the hydraulic cylinder detected by the stroke sensor and the mold clamping force detected by the mold clamping force sensor are stored in advance. In addition, a change pattern storage unit that converts the change pattern of the mold opening amount and the change pattern of the mold clamping force of the mold set in the mold clamping condition setting unit into a change pattern of the stroke of the hydraulic cylinder, Feedback control to the mold clamping servo valve according to the change pattern of the stroke of the hydraulic cylinder and the change pattern of the pressure in the mold of the paint. Mold coating forming apparatus characterized by comprising a mold clamping control unit to perform. 6. A toggle type electric injection molding machine in place of the toggle type injection molding machine, a mold clamping drive ball screw in place of the mold clamping drive hydraulic cylinder, and a servo motor in place of the mold clamping servo valve. The in-mold coating forming apparatus according to claim 5, wherein