JP2002103401A - Injection compression molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection compression molding method capable of rapidly and efficiently performing the one-cavity or multi-cavity molding of a molded article of high accuracy and capable of employing simple apparatus constitution. SOLUTION: When injection compression molding is performed in the injection compression molding method using a mold apparatus having movable cores (5A and 5B) capable of advancing into and retrerating from cavities (1A and 1B), the cavities are filled with a resin. In this resin filling operation, a step, wherein the positions of the movable cores (5A and 5B) retreating by the resin pressure of the molten resin charged in the cavities through hot runners (10A and 10B) are detected by position sensors (6A and 6B) and the moving speeds of the movable cores (5A and 5B) are calculated on the basis of the outputs of the position sensors, and a step, which performs the feedback control of the flow rate of the molten resin charged in the cavities on the basis of the calculated moving speed data of the movable cores, are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an injection compression molding method.

[0002]

2. Description of the Related Art In injection compression molding, which is one of the plastic molding methods, a high-temperature resin melted and kneaded by a molding machine is poured into a molding space (cavity) in a mold and a constant pressure is applied in the mold. By cooling and solidifying with
The plastic is shaped into a predetermined shape. However, since the state of filling the cavity with the molten resin is slightly changed by various factors, it is very difficult to obtain a uniform molded product.

[0003] That is, multi-cavity in which resin is injected into a plurality of cavities at a time to produce a plurality of molded products at once is generally performed.
If the process of filling each cavity with resin is observed with an insufficiently filled product or observed with a visualization mold, the filling time etc. will vary among the cavities, and the histories at the time of molding will differ, so uneven filling will occur. It turned out to be. The filling speed and the filling amount of the resin into the A cavity and the B cavity are slightly different due to unevenness in the temperature of the resin and errors in the finished dimensions of the mold such as the runner diameter. Conventionally, in order to eliminate such variations, the weight of a molded product obtained in each cavity is measured, and the flow rate of the resin is adjusted so as to eliminate the weight difference between the cavities. In this case, if the molding conditions are changed, there is a problem that it takes much time and effort, such as the necessity of performing the adjustment operation again. Furthermore, a method has been proposed in which the resin pressure in the cavity is detected and the flow rate of the filled resin is controlled based on the detected pressure. There is a problem that accurate control of the flow rate cannot be expected based on the data because it is easily affected by the frictional resistance and it is difficult to accurately detect the flow rate. The situation is the same in single-cavity injection molding, and it is difficult to obtain a highly uniform molded product because the filling state of the resin varies for each shot.

[0004] Specific examples of resin molded articles requiring a high degree of uniformity include, for example, CD, MD, DVD, and DVD-R.
And optical information recording media. In these optical information recording media, minute pits and / or grooves are transferred to the entire surface of one surface of a disk, and the other surface is formed as a flat surface. Laser light is vertically incident from this flat surface, and changes in the amount of reflected light or transmitted light due to the unevenness of the pits and / or grooves are converted into digital signals. Therefore, it is important that these discs transfer minute pits and / or grooves accurately. Further, as described above, in order to read the amount of change in reflected light or transmitted light of laser light,
It is important to improve the flatness and the thickness uniformity of the laser beam incident surface. In particular, a DVD on which very high-density information is recorded, and a DVD-R on which information is recorded by a writer
Strict control over these is required. Also,
Data is recorded on at least one of the front and back sides of the disc,
An optical information recording medium such as a DVD-R that can be reproduced is manufactured by laminating two thin disks. In this case, a difference in molding conditions between the two disks to be laminated, and If there is uneven transfer, uneven thickness, etc., there is a problem in that, after bonding, they are peeled off or deformed due to aging. Therefore, it is necessary that the shapes and characteristics of these two disks be as uniform and identical as possible. However, a molded product that satisfies these requirements has not been achieved by conventional injection molding technology. For this reason, it is necessary to newly develop an injection compression molding method capable of performing precise molding with extremely little variation.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to solve the drawbacks of the prior art and to minimize variations in the weight of molded articles. An object of the present invention is to provide an injection compression molding method capable of obtaining a molded article having high homogeneity. Further, the present invention can be applied to a mold apparatus of a core compression type using a movable mold core, a mold apparatus of a parting compression type using a so-called inro-type mold, and further to a single-cavity mold apparatus. Another object of the present invention is to provide an injection compression molding method that can be applied to a multi-cavity mold apparatus and has a wide range of use.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to fill resin into a cavity when performing injection compression molding using a mold device having a movable mold core that can move into and out of the cavity; Detecting the position of the movable core receding by the resin pressure of the molten resin filled in the cavity by a position sensor, and calculating a moving speed of the movable core based on an output of the position sensor; Feedback controlling the flow rate of the molten resin to be filled into the cavity based on the moving speed data of the mold core; and performing the injection compression molding method.

In this case, a predetermined pressure is applied to the movable core in advance, and filling of the cavity with the molten resin is started while the movable core is advanced to the parting line side. Based on the moving speed data when the movable core gradually retreats, the gate is completely closed when the movable core reaches a predetermined position while feedback-controlling the flow rate of the molten resin filling the cavity. It is recommended that

[0008] Still another object of the present invention is to provide a resin filling operation into a cavity when performing injection compression molding using an injection-mold-type mold device in which a movable-side mold and a fixed-side mold are fitted to each other. Detecting the position of the movable mold retracted by the resin pressure of the molten resin filled into the cavity through the hot runner with a position sensor, and calculating the moving speed of the movable mold based on the output of the position sensor. And a step of feedback-controlling the flow rate of the molten resin to be filled into the cavity based on the obtained moving speed data of the movable mold. The method can be achieved by an injection compression molding method.

In this case, a predetermined pressure is applied to the movable mold in advance, and filling of the molten resin into the cavity is started in a state where the mold is clamped. It is recommended that the gate be completely closed when the movable mold reaches a predetermined position while feedback-controlling the flow rate of the molten resin filling the cavity based on the moving speed data when gradually moving backward. .

The flow rate of the molten resin to be filled into the cavity can be controlled by adjusting at least one of the opening degree of the valve, the injection speed of the injection machine, and the temperature of the molten resin.

When injection compression molding is performed using a multi-cavity mold device having a plurality of cavities, the flow rate of the molten resin in each cavity is controlled so as to be uniform. In addition, when performing injection compression molding using a single-cavity mold device having one cavity,
Control is performed so that the flow rate of the molten resin for each shot is unified.

When a valve gate type hot runner is used, the valve can be used to open and close the gate and adjust the flow rate. It is also recommended to use a valve gate type hot runner in which the gate opening / closing part is not close to the cavity and is configured to store one or more shots of molten resin between the gate opening / closing part and the cavity.

The position sensor has a resolution B (unit: mm); and a thickness t (unit: m) of a molded product to be manufactured.
m), when the required thickness variation is A (unit:%) or less, it is desirable that the relationship satisfy the relational expression of B ≦ (A · t) / 200.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a first stage of filling a cavity of a core compression multi-cavity mold device with a molten resin by an injection compression molding method according to the present invention;
FIG. 2 is a schematic sectional view showing the second stage; FIG. 3 is a schematic sectional view showing the third stage; FIG. 4 is an explanatory diagram showing an example of a control device provided in the mold apparatus; Is a sectional view showing a first example of a valve gate type hot runner used in the present invention; FIG. 6 is a sectional view showing a second example of the valve gate type hot runner used in the present invention; FIG. FIG. 8 is an explanatory view showing the filling state of the molten resin in the cavity stepwise and in detail; FIG. 8 shows filling of the molten resin into the cavity of an injection-mold single-cavity mold apparatus by the injection compression molding method according to the present invention. FIG. 9 is a schematic cross-sectional view showing the state; FIG. 9 is a graph showing the variation in the core position between each cavity or each shot when the filling operation of the molten resin into the cavity is performed by controlling the position of the movable core; Filling operation of molten resin into cavity A; a graph showing the variation of the core positions between the cavities or each shot in the case of the time control by a timer.

In the multi-piece (two-piece) mold apparatus shown in FIGS. 1 to 3, 1A and 1B are cavities, 2 is a movable mold, 20 is a movable platen, 3 is a fixed mold, 3
Reference numeral 0 denotes a fixed platen, 4 denotes an injection nozzle, 5A and 5B denote movable cores provided for the cavities 1A and 1B, 50A and 50B denote cylinders for driving the movable cores 5A and 5B, and 6A and 6B denote cylinders. A position sensor for detecting the position of the movable core, 7 is a controller for controlling the operation of the entire mold apparatus, 8A and 8B are gates, 10A and 10B are hot runners for supplying molten resin to cavities 1A and 1B, 10a , 10b are hot runners 10A,
10B is a valve control device, 13A and 13B are valves, and PL is a parting line between the movable mold 2 and the fixed mold 3. FIG. 4 shows the configuration of the control device 7.
In the figure, 7a is an input signal processor, 71 is its process card, 72 is an I / O card, 7b is a control output signal transmitting processor, 73 is its process card, and 74 is an I / O card. 6A and 6B are the position sensors, and 50A and 50B are the cylinders for driving the movable cores 5A and 5B.
10b is the valve control device.

The features of the injection compression molding apparatus shown in FIGS. 1 to 3 are as follows: (1) Since the molten resin filled in the cavities 1A and 1B is independently pressurized, the movable mold 2 is independently formed. The movable cores 5A and 5B that can be controlled are provided (so-called core compression); (2) The filling state of the molten resin in the cavities 1A and 1B is individually detected, and based on this, the flow rate of the resin and the sealing operation of the gate are performed. Position sensors 6A and 6B capable of individually detecting the positions of the movable cores 5A and 5B, respectively;
A, valve gate type hot runners 10A, 10B having valves 13A, 13B are used as means for individually adjusting the flow rate of the molten resin supplied through A, 8B and individually opening and closing these gates; (4)
After the mold is closed, filling of the cavity 1A, 1B with the molten resin is started. Thereafter, while detecting the positions of the movable cores 5A, 5B with the position sensors 6A, 6B, the movable cores are detected based on the position information. 5A and 5B are calculated, and the valve control device 10 is controlled so that both speeds are constant.
The flow rate of the resin is adjusted by controlling the opening degrees of the valves 13A and 13B of the hot runners 10A and 10B by controlling the gates 8A and 10B when the movable core reaches a predetermined position. 8B are individually closed to stop the filling of the molten resin, and the movable mold cores 5A and 5B are independently pressed to pressurize the resin in the cavities 1A and 1B, and the mold is opened after a predetermined cooling time has elapsed. And a control device 7 for automatically performing a series of operations of taking out a molded product; and the like.

When the injection compression molding is performed by the apparatus shown in FIGS. 1 to 3, first, the melt-plasticized resin is divided by the injection molding machine from the injection nozzle 4 into the fixed mold 3 in the divided direction. Each hot runner 10 through roads 3a and 3b
A, 10B and the gate 8 at the tip of each runner
A and 8B are filled into the cavities 1A and 1B (see FIG. 1).

At this time, as will be described later in detail with reference to FIG. 7, prior to filling the molten resin, the movable cores 5A, 5B
A predetermined pressure P1 is applied to the movable cores 5A and 5A in advance.
In a state where B has been advanced to the parting line PL side, resin filling is started. The cavities 1A and 1B are gradually filled with resin, and when the cavity internal pressure becomes equal to or higher than the above P1, the movable cores 5A and 5B are gradually retracted by the pressure. The positions of the movable cores 5A and 5B are individually detected at predetermined sampling times by position sensors 6A and 6B provided for the respective movable cores, and the output is provided to the control device 7.

In the control device 7, the position sensor 6
The moving speeds of the movable cores 5A and 5B are calculated based on the position information of the movable cores 5A and 5B, which are provided from A and 6B, and the moving speeds of the movable cores 5A and 5B coincide with a predetermined appropriate moving speed. At least one of the opening degrees of the valves 13A and 13B, the temperature of the molten resin, the injection speed of the injection machine 4, and the like is adjusted so that the moving speeds are the same.

Thus, first, the cavity 1
When the position sensor 6A detects that the A is fully charged and the movable core 5A has retreated to a predetermined position, a signal is sent from the control device 7 to the valve control device 10a of the valve gate type hot runner 10A. Then, as shown in FIG.
A is advanced toward A, and the gate 8A is completely closed. Next, a signal is sent to the driving cylinder 50A of the movable core 5A to operate it, and the movable core 5A is moved into the cavity 1A.
By moving inward, the molten resin in the cavity is compressed to make the pressure distribution in the cavity uniform.
At this time, the scanning time of each detection value for controlling the movable core 5A and the valve 13A is 2 msec or less. Preferably 1 msec or less, more preferably 5 msec or less.
00 μsec or less.

Next, when it is detected by the position sensor 6B that the cavity 1B has been completely filled and the movable core 5B has retracted to a predetermined position in the same manner, the control device 7 returns to A signal is sent to the valve control device 10b of the valve gate type hot runner 10B, and as shown in FIG. 2, the valve 13B is advanced toward the gate 8B to completely close the gate 8B.
Next, a signal is sent to the driving cylinder 50B of the movable core 5B to operate it, and the movable core 5B is moved to the cavity 1B.
B is advanced toward the inside, and the molten resin in the cavity is compressed to make the pressure distribution in the cavity uniform. Thereafter, after a predetermined cooling time has elapsed, the mold is opened and the molded products in the cavities 1A and 1B are taken out.

A valve gate type hot runner used in the above-mentioned mold apparatus is a valve (needle valve) that is provided with a heater for preventing the temperature of the molten resin from decreasing, and that can open and close the nozzle gate. , Etc.), and a first example thereof will be described with reference to FIG. A valve gate type hot runner 10A shown in FIG. 1 includes a hot nozzle 11, a heater 12, a valve (needle valve) 13A, an actuator 14, a limit bar 15, and the like. Actuator 1
Reference numeral 4 includes a piston 14a, a cylinder chamber 14b, a piston rod 14c, and the like.

The molten resin is supplied to the inlet 11 of the hot nozzle 11
a, and is injected and filled into the cavity from the gate 11c at the tip through the inner hole 11b. During the resin filling period, the opening of the gate 11c is adjusted by controlling the operation of the actuator 14 via the valve control device 10a and finely adjusting the position of the tip a of the valve 13A up and down near the gate 11c. Then, the flow rate of the molten resin injected and filled into the cavity can be adjusted. Also, by adjusting the current to the heater 12, the temperature of the resin can be adjusted, and the flow characteristics of the resin can be changed. Thus, the flow rate of the molten resin filled in the cavity can be adjusted. it can. That is, even at the same resin pressure, the higher the resin temperature, the higher the fluidity and the higher the flow rate.

When a predetermined amount of resin is filled in the cavity, the actuator 14 is operated to operate the valve 1.
The gate 11c can be completely closed by advancing the tip of 3A to the position b near the tip of the hot nozzle 11. In the illustrated example, the limit bar 15 attached to the upper end of the piston rod 14c is provided with a stopper not shown in the drawing so that the tip of the valve 13A does not advance beyond the position b while the mold is closed. To prevent the valve 13A from moving forward (downward) any more.

FIG. 6 shows a second example of the valve gate type hot runner. In this hot runner,
The gate opening / closing part is not close to the cavity, and at least one shot of the molten resin can be stored and stored in the heated and molten state between the gate opening / closing part and the cavity. In the valve gate type hot runner having such a configuration, the gate opening / closing portion is separated from the cavity, and one shot or more of the molten resin stored in the inner hole 11b is injected and filled into the cavity. A molded product or the like that requires good optical characteristics can be molded without being affected by the merging of the molten resins by the valve 13A, without impairing the characteristics. Further, when the flow rate is controlled by controlling the temperature of the resin, the temperature of the resin to be filled in the next shot can be accurately managed in advance, which is very suitable for use in the present invention.

Here, the operation of filling the resin into the cavities, which has been schematically described with reference to FIGS. 1 to 3, will be described in detail by taking one cavity 1A as an example with reference to FIG.

First, at a stage before injection, a predetermined pressure P1 is applied to the movable core 5A in advance, and the movable core 5A is advanced to the parting line PL side. As shown in (), filling of the resin from the valve gate type hot runner 10A into the cavity 1A is started.

When the resin is gradually filled in the cavity 1A and the pressure in the cavity becomes equal to or higher than the pressure P1,
The movable core 5A is gradually retracted by the pressure as shown in FIG. The position of the movable core 5A at that time is detected by a position sensor 6A including a magnescale 61a attached to the side surface of the movable core 5A and its read head 62a. In the present invention, the moving speed of the movable core 5A is calculated by the control device 7 based on the position information, and if the moving speed does not coincide with a predetermined value, the opening degree of the valve 13A, the resin temperature, the injection speed, etc. The resin is filled while controlling at least one of the steps so as to increase or decrease the flow rate of the resin so as to be a predetermined value.

The movable core 5A continues to retreat, and its tip 5
When A-1 reaches a predetermined position indicated by an arrow c as shown in FIG. 7C (that is, when a predetermined amount of resin required for the molded article is filled in the cavity), This is detected based on the output of the position sensor 6A, a signal is sent from the control device 7 to the valve control device 10a, and the valve 13A of the valve gate type hot runner 10A is pushed out to close the runner gate 8A.

It is recommended to use a position sensor having a resolution of 5 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less. The sampling time of the detection value of the position sensor is 1 msec or less, preferably 50 μsec or less, and more preferably 25 μm or less. At this time, the scanning time of each detection value for controlling the movable core and the valve is 2 msec or less, preferably 1 msec or less, and more preferably 500 μsec.
The following is assumed.

After closing the gate 8A as described above, in order to perform compression molding, a signal is sent to the driving cylinder 50A of the movable mold core 5A to operate it, and the movable core 5A is actuated.
A is advanced toward the inside of the cavity 1A to compress the molten resin in the cavity, thereby making the pressure distribution in the cavity uniform and, at the same time, compressing the resin in the cavity 1A until the resin pressure reaches a predetermined value. That is, as shown in FIG. 7D, while the pressure P2 is applied to the movable core 5A to increase the resin pressure in the cavity, the resin in the cavity is cooled and solidified. When a predetermined cooling time has elapsed and the resin in all the cavities has solidified, the mold is opened and the molded product is taken out.

In the present invention, the calculation of the moving speed of the movable core (or the movable mold) is not limited to the case where the moving speed is actually calculated. Is started, and if the position of the movable core (or movable mold) provided from the position sensor after a certain time has not reached the predetermined position, the moving speed is lower than the predetermined value. Such as controlling to increase the flow rate of the resin to determine the appropriate amount of movement corresponding to the elapsed time and the actual position information to simply determine whether the moving speed is appropriate or not, This is included in the concept of calculating the moving speed according to the present invention.

In the embodiment shown in FIGS. 1 to 3, the number of cavities and the number of valve gate type hot runners and movable cores are increased to increase the number of cavities. You can increase the number. Conversely, it will be easily understood that the present invention can be applied to a case where a single-cavity core compression mold device having only one cavity is used.

Here, the position sensors 6A, 6B required to suppress the variation in the thickness of the molded product within a predetermined range.
, Etc. will be briefly described. For example, if the resolution of the position sensor is 10 μm, an error of 10 μm occurs before and after the reference position as a center, and the thickness variation of the molded product is (10 × 2) μm. Therefore, the resolution of the position sensor is B (mm), the thickness of the obtained molded product is t (mm), and the variation in the thickness is A.
(%), (B / t) × 100 × 2 ≦ A must be satisfied in order to suppress the variation to A (%) or less. From this equation, a relational expression of B ≦ (A · t) / 200 is derived for the resolution B of the position sensor. For example, a molded product having a thickness t = 1.27 mm is
The resolution B of the position sensor required when manufacturing with a thickness variation A of 1% or less is calculated from the above relational expression as B ≦ (1 × 1.27) /200=0.0064 (mm).
= 64 (μm), and it is necessary to use a position sensor having a resolution B of 64 μm or less. in this way,
The resolution required for the position sensor is determined from the thickness variation accuracy required for the molded article to be manufactured. Similarly, repeatability is required. In addition, such a resolution is sufficient for measuring the moving speed of the movable core and the movable mold.

Next, the case where the method of the present invention is carried out using the mold apparatus shown in FIG. 8 will be described. This device is
A single-cavity injection compression molding apparatus, in which a movable gate mold 2 and a fixed mold 3 are configured to fit each other around a cavity portion, a mold having a so-called intaglio structure, and a valve gate mold hot mold. A runner 10 is provided. In the figure,
1 is a cavity, 2 is a movable mold, 20 is a movable platen, 3 is a fixed mold, 30 is a fixed platen, 21 is
The movable platen 20 and the movable mold 2 are fixed to the fixed mold 3
Cylinder for driving forward and backward, 4 is an injection nozzle, 6 is a position sensor for detecting the position of the movable mold 2, 7 is a control device for controlling the operation of the whole mold apparatus, 8 is a gate, 10 is a gate Valve gate type hot runner, 10a
Is a valve control device, 13 is a valve, and PL is a parting line between the movable mold 2 and the fixed mold 3.

The characteristics of the injection compression molding apparatus shown in FIG.
(1) The pressure of the molten resin filled in the cavity 1 is
This is performed by advancing the movable mold 2 itself of the intaglio mold toward the fixed mold 3 (so-called parting compression); (2) detecting the filling state of the molten resin in the cavity 1 and In order to control the flow rate of the resin and the sealing operation of the gate, a position sensor 6 capable of detecting the position of the movable mold 2 is provided; (3) The flow rate of the molten resin supplied through the gate 8 is adjusted and The use of a valve gate type hot runner 10 having a valve 13 as means for opening and closing the gate 8; (4) After the mold is closed, filling of the cavity 1 with the molten resin is started, and While the position of the movable mold 2 is detected by the sensor 6, the moving speed of the movable mold 2 is calculated based on the position information, and the valve control device 1 is set so that the moving speed becomes a predetermined value. a, the opening of the valve 13A of the hot runner 10 is adjusted, etc., and when the movable mold 2 reaches a predetermined position, the gate 8 is closed to stop filling the molten resin. A control device 7 is provided for automatically performing a series of operations of pressing the movable mold 2 to pressurize the resin in the cavity 1 and opening the mold after a predetermined cooling time has elapsed to remove the molded product. And so on.

It will be easily understood that the same operation as that shown in FIG. 7 can be performed by using the apparatus shown in FIG. 8 to fill the cavity 1 with the molten resin while suppressing the variation between shots. . That is, in order to perform the same filling operation as in FIG. 7, the cylinder 21 is driven, a predetermined pressure P1 is applied to the movable mold 2 in advance, and the resin is filled into the cavity 1 through the gate 8 with the mold clamped. Is started, and when the movable mold 2 gradually retreats against the pressure P1 with the filling of the resin, while detecting the position by the position sensor 6,
The flow rate of the resin is controlled by controlling the drive of the valve 13 based on the positional information. Thereafter, when the inner wall surface 2a of the movable mold reaches the predetermined position indicated by the arrow c, the position is detected by the position sensor 6, and the valve 13 is pushed out based on this, and the gate 8 is completely closed. Thereafter, the movable mold 2 may be slightly extruded for compression molding to increase the cavity internal pressure.

The present invention is characterized in that the flow rate of the resin is adjusted based on the moving speed of the movable core and the movable mold. However, as in the above embodiment, the movable core and the movable mold are controlled. When the gate is cut by determining the filling state of the cavity based on the position of the mold, the position sensor provided for that purpose can also be used as a data collection unit for controlling the flow rate of the resin. It is a target.

As in the above embodiment, when the filling state of the resin into the cavity is detected based on the position of the movable core or the movable mold, and the gate is cut by this, when starting the filling, The variation in weight of the molded product can be extremely reduced as compared with the case where the gate is cut by time control. This will be described with reference to FIGS. FIG. 9 shows that the gate seal is performed based on the position of the movable mold core or the movable mold as in the above embodiment, and the core stop position upon completion of the gate seal when molding is performed a plurality of times. Are shown. In this case, the weight variation of the filling resin is 1.5%
Met. On the other hand, FIG. 10 shows the variation of the core stop position at the completion of the gate seal when the timer control is performed to uniformly perform the gate seal after a predetermined time has elapsed from the start of the filling according to the conventional technology. It is shown that the weight variation of the filling resin in the case is 6.6%. It can be understood that the variation in FIG. 9 is much lower than this variation.

According to the present invention having the above-described structure, a molded product having uniform quality can be efficiently molded. When the quality of the molded product is evaluated based on the weight variation of the product for each type of control method, the following is obtained. 1) ×: A method in which the resin filling state in the cavity is not detected. 2) ○: A method of detecting the filling state by the pressure in the cavity. 3) ◎: A method of detecting the resin filling state based on the position of the movable core or the movable mold and controlling the flow rate of the resin based on the moving speed of the movable core or the movable mold (the present invention). . The variation of the properties such as the density of the molded article is large in the order of × >>○> ◎. That is, a method of detecting and controlling the resin filling state based on the pressure in the cavity is preferable to not detecting the resin filling state in the cavity. It is further preferable to detect the position of the movable core or the movable mold and control the flow rate of the resin based on the moving speed of the movable core or the movable mold to perform filling.

[0041]

According to the present invention, the flow rate of the resin to be filled into the cavity is maintained at a predetermined value.
Since the control is performed based on the moving speed of the movable mold core or the movable side mold, the injection according to the present invention can form a high-precision molded product quickly and efficiently by relatively simple means. A compression molding method can be provided. Therefore, the present invention is applied to CD-R, DVD, DVD-
It is particularly suitable for molding optical information recording media such as R. In addition,
The present invention is not limited to the above embodiments, but encompasses all modifications within the scope of the objects that can be easily conceived by those skilled in the art from the above description.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a first stage of filling a molten resin into a cavity of a core compression multi-cavity die apparatus by an injection compression molding method according to the present invention.

FIG. 2 is a schematic sectional view showing a second stage.

FIG. 3 is a schematic sectional view showing a third stage.

FIG. 4 is an explanatory view showing an example of a control device provided in the injection compression molding apparatus according to the present invention.

FIG. 5 is a sectional view showing a first example of a valve gate type hot runner used in the present invention.

FIG. 6 is a sectional view showing a second example of the valve gate type hot runner used in the present invention.

FIG. 7 shows a state in which one cavity is filled with a molten resin.
It is explanatory drawing shown in detail step by step.

FIG. 8 is a schematic cross-sectional view showing a state in which a cavity of an injection-mold single-cavity mold device is filled with a molten resin by the injection compression molding method according to the present invention.

FIG. 9 is a graph showing variations in core position between cavities or shots when a cavity is filled with molten resin by controlling the position of a movable core.

FIG. 10 is a graph showing variations in the core position between cavities or shots when the operation of filling the molten resin into the cavities is performed by time control using a timer.

[Explanation of symbols]

 1A, 1B, 1 Cavity 2 Movable mold 20 Movable platen 3 Fixed mold 3a, 3b Dividing channel 30 Fixed platen 4 Injection nozzle 5A, 5B Movable core 6A, 6B, 6 Position sensor 7 Control device 7a Input Signal processing processor 7b Output signal transmission processor for control 8A, 8B, 8 Gate 10A, 10B, 10 Hot runner 13A, 13B, 13 valve PL Parting line

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kenji Kuwabata 2-1-1 Tangodori, Minami-ku, Nagoya-shi, Aichi Prefecture Inside Mitsui Chemicals, Inc. (72) Hideto Ogasawara 2-1-1 Tangodori, Minami-ku, Nagoya-shi, Aichi Prefecture Address Mitsui Chemicals Co., Ltd. (72) Inventor Mitsuharu Mikawa 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi F-term (reference) 4F202 AP06 AP07 AP11 AR06 AR07 AR14 CA11 CK07 CK18 CK52 CK73 CK83 CK89 4F206 AP064 AP074 AP11 AR063 AR076 AR14 JA03 JL02 JM04 JM16 JN14 JN15 JN25 JP17 JQ81 JQ88

Claims (10)

[Claims] 1. In a resin filling operation into a cavity when performing injection compression molding using a mold device having a movable mold core (5A, 5B) capable of moving into and out of the cavity (1A, 1B); The positions of the movable cores (5A, 5B) which recede by the resin pressure of the molten resin filled into the cavity through the (10A, 10B) are detected by the position sensors (6A, 6B), and based on the outputs of the position sensors. Calculating the moving speed of the movable core (5A, 5B); and performing feedback control of the flow rate of the molten resin to be filled into the cavity based on the determined moving speed data of the movable core. Injection compression molding method. 2. A predetermined pressure (P1) is previously applied to the movable cores (5A, 5B), and this is applied to a parting line (P).
While the cavity is being advanced to the side L), the filling of the molten resin into the cavity is started.
The movable cores (5A, 5B) are moved to predetermined positions while controlling the flow rate of the molten resin filling the cavity based on the moving speed data when the movable cores (5A, 5B) gradually retreat against The injection compression molding method according to claim 1, wherein the gates (8A, 8B) are completely closed when (c) is reached. 3. A cavity (1) when performing injection compression molding using an intaglio mold device in which a movable mold (2) and a fixed mold (3) are fitted to each other. In the resin filling operation; the position of the movable mold (2) which recedes due to the resin pressure of the molten resin filled into the cavity through the hot runner (10) is detected by the position sensor (6), and the output of the position sensor is output. Calculating the moving speed of the movable mold (2) based on the above; and performing feedback control of the flow rate of the molten resin to be filled into the cavity based on the determined moving data of the movable mold. Injection compression molding method. 4. A predetermined pressure (P) is applied to the movable mold (2) in advance.
1) is applied, the filling of the molten resin into the cavity is started with the mold clamped, and the moving speed when the movable mold (2) gradually retreats against the pressure (P1) with the filling of the resin. 4. The gate according to claim 3, wherein the gate is completely closed when the movable mold reaches the predetermined position while feedback controlling the flow rate of the molten resin filling the cavity based on the data. Injection compression molding method. 5. The method according to claim 1, wherein the flow rate of the molten resin filled in the cavity is controlled by adjusting at least one of a valve opening, an injection speed of an injection machine, and a temperature of the molten resin. The injection compression molding method according to claim 1. 6. In the case of performing injection compression molding using a multi-cavity mold device having a plurality of cavities, control is performed such that the flow rates of the molten resin in each cavity are unified. The injection compression molding method according to any one of the above. 7. In the case where injection compression molding is performed using a single-cavity mold device having one cavity, control is performed such that the flow rate of the molten resin for each shot is unified. The injection compression molding method according to any one of the above. 8. A hot runner of a valve gate type (10).
A, 10B, 10) and their valves (13A, 13A).
The injection compression molding method according to any one of claims 1 to 7, wherein the gates (8A, 8B, 8) are opened / closed and the flow rate is adjusted by using (B, 13). 9. A valve gate type hot runner configured such that the gate opening / closing part is not close to the cavity and one or more shots of molten resin are stored between the gate opening / closing part and the cavity. 9. The injection compression molding method according to any one of items 1 to 8. 10. The position sensor (6A, 6B, 6).
When the thickness B of the molded article to be manufactured is t (unit: mm) and the required thickness variation is A (unit:%) or less, B ≦ (A · t The injection compression molding method according to any one of claims 1 to 9, which satisfies a relational expression of (1) / 200.