JP2006231643A - Molding method, mold, molding formed by it, and information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably mass-produce a good quality molding by opening a mold without applying a load to the peripheral end of a molding in a molding ejection process and ejecting the molding without deforming a burr formed at the peripheral end of the molding. <P>SOLUTION: In the molding ejection process, mold opening is started after a vent clearance 12 is enlarged by moving-back a peripheral ring 7 forming the vent clearance 12 with a stamper 4, the mold is opened without applying bending force to the burr 15 formed by a resin introduced into the vent clearance 12, and the molding is ejected without deforming the burr 15 formed along the surface of the molding to which a relief pattern formed on the surface of the stamper 4 is transferred. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molding method for producing a molded substrate or the like of an optical information recording medium by an injection molding method, a molding die, a molded product, and an information recording medium, in particular, reduction of the influence of burrs generated at the end of the molded product.

  In order to record information at a high density and to increase the capacity, an optical disk having a structure in which a disk substrate is bonded has been developed. A problem in the production of a medium has become apparent with respect to the optical disk on which the disk substrate is bonded. As shown in FIG. 7A, this problem occurs when a disk substrate 14 is molded and manufactured, and a burr 30 that is a protrusion in the vertical direction is generated at the outer peripheral end. A protective film 16 is formed on the surface of the disk substrate 14 having the burrs 30 as shown in FIG. 7B, and the protective film side of the two disk substrates 14 having the protective film 16 is coated with an adhesive. As shown in FIG. 7 (c), the bonded optical disc 31 has a warp 32 at the outer peripheral end, or an unbonded region 33 at the outer peripheral end as shown in FIG. 7 (d). Thus, if there is a warp 32 at the outer peripheral edge of the optical disc 31 or a portion 33 with insufficient adhesion, the quality will deteriorate in that region.

  The burr 30 generated at the outer peripheral edge of the disk substrate 14 is a phenomenon depending on the structure of a molding die for manufacturing the disk substrate 14. As shown in the partial cross-sectional view of the outer peripheral portion of FIG. 8, the substrate molding die that is generally used at present has a fixed mold 2 and a movable mold 3. The fixed mold 2 is transferred to the disk substrate 14. The movable mold 3 includes a mirror block 6 placed on the movable mold body 5 and an outer ring 7 provided on the outer peripheral portion of the mirror block 6. Have The outer peripheral ring 7 is pressed toward the fixed mold 2 by the elastic force of the elastic support 34 embedded in the outer edge of the movable mold main body 5, and the inner peripheral surface pushes the bearing 10 against the outer peripheral end surface of the mirror block 6. The forward limit is restricted by the outer peripheral ring support member 9 provided on the outer peripheral portion. An abutting member 11 that engages with the outer peripheral ring 7 is provided on the outer peripheral portion of the fixed mold 2.

  Normally, when the movable mold 3 of the molding die is advanced to the fixed mold 2 side and fitted with the fixed mold 2, as shown in FIG. 9A, there is a gap between the stamper 4 and the outer ring 7. A vent clearance 12 is provided to lead out the gas discharged from the molten resin injected into the cavity from the center of the mold and the air in the cavity discharged by the molten resin to the outside. In order to obtain good quality up to the outer peripheral edge of the disk substrate 14, the molten resin must be completely filled up to the outer peripheral edge of the cavity. For this reason, the molten resin flows into the vent clearance 12 and is formed. Burr is generated at the outer peripheral edge. The vent clearance 12 is an indispensable part in a mold for injection or injection compression molding, and the stamper 4 and the outer ring 7 cannot be brought into close contact with each other in order to prevent the generation of burrs.

  In order to prevent the occurrence of this burr, as shown in Patent Document 1, the ridge angle between the stamper 4 and the outer ring 7 is set to 90 degrees or more to reduce the pushing force of the molten resin against the vent clearance 12. The injection molding is nothing but a processing method in which the molten resin is replaced with the air in the cavity or the gas discharged from the molten resin, and the occurrence of burrs is an unavoidable phenomenon.

  The burr that becomes a problem when the disk substrates are bonded together is a burr generated in the vertical direction of the molded disk substrate. A process in which burrs generated in the vertical direction of the disk substrate will be described with reference to FIG.

  As described above, the outer peripheral ring 7 of the movable mold 3 is slidably installed on the movable mold body 5. This is to keep the vent clearance 12 constant during filling of the molten resin even when the cavity internal pressure increased by filling the molten resin becomes larger than the clamping pressure and the mold is opened. As shown in FIG. 9 (a), when the molten resin 23 is filled in the cavity as shown in FIG. There is a case where the cavity internal pressure exceeds the mold clamping pressure but the movable mold body 5 is slightly retracted. If the outer peripheral ring 7 is fixed to the movable mold main body 5, the outer peripheral ring 7 is also retracted as the movable mold main body 5 is retracted. This phenomenon leads to an increase in the vent clearance 12, and the filled molten resin 23 flows out of the cavity. The amount of retraction of the movable mold body 5 sometimes reaches several hundred μm, and is a retraction amount that clearly causes a problem as compared with the vent clearance 12 originally set to 10 to 20 μm. At this time, the outer peripheral ring 7 is moved forward relative to the movable mold body 5 by the elastic force of the elastic support 34 in order to compensate for the retreat of the movable mold body 5 that is relatively separated, and comes into contact with the abutting member 11. And the vent clearance 12 is maintained at a constant interval. Thereafter, from the latter half of the filling process of the molten resin 23 to the cooling process, the cavity internal pressure decreases due to solidification shrinkage of the molten resin 23, and the mold clamping pressure eventually exceeds the cavity internal pressure, and as shown in FIG. The mold body 5 moves forward again, the outer ring 7 moves relatively backward to keep the distance between the vent clearances 12, and the molten resin that has flowed into the vent clearances 12 is burrs in the horizontal direction along the surface of the molded substrate 14. It becomes 15. The burr 15 along the surface of the substrate 14 formed in this way does not cause a problem even if the substrate 14 is bonded, but the burr 15 becomes perpendicular to the substrate 14 in the step of taking out the substrate 14. End up.

Mold opening starts in the step of taking out the molded substrate 14, and as shown in FIG. 9D, when the movable mold body 5 starts to move backward, the molded substrate 14 also moves backward. On the other hand, the outer peripheral ring 7 maintains a state in contact with the abutting member 11 by the elastic force of the elastic support 34. For this reason, the burr 15 formed on the outer peripheral edge of the substrate 14 is bent in the direction by the force applied by the inner peripheral surface end portion of the outer peripheral ring 7 as the movable mold body 5 moves backward. Change vertically. When the mold opening further proceeds and the outer ring 7 engages with the outer ring support member 9, the outer ring 7 also moves back together with the movable mold body 5 to complete the mold opening. The burr 15 changes to a burr 30 perpendicular to the surface of the substrate 14 in the step of taking out the substrate 14 thus formed. For this reason, as described above, warpage or the like occurs in the outer peripheral portion of the optical disk on which the substrates are bonded.
Japanese Patent No. 2582420

  The present invention performs a mold opening operation without applying a load to the outer peripheral end of the molded product in the process of taking out the molded product, and takes out the molded product without deforming the burr generated at the outer peripheral end of the molded product. It is an object of the present invention to provide a molding method, a molding die, a molded product formed by the molding method and an information recording medium capable of stably mass-producing the product.

  The molding method according to the present invention includes a stamper provided on a fixed mold and having a relief pattern to be transferred to a molded product, a mirror block provided on a movable mold so as to face the stamper, and an outer peripheral portion of the mirror block. In the molding method for producing a molded product by injecting molten resin while exhausting the gas in the cavity formed by the outer peripheral ring provided in the vent clearance formed by the stamper and the outer peripheral ring, and cooling and solidifying the molten resin, The mold opening is started after the outer peripheral ring is retracted and the vent clearance is expanded in the process of taking out the molded product.

  The amount of retraction of the outer ring is preferably less than the thickness of the molded product.

  A molding die according to the present invention includes a stamper provided on a fixed die and having a relief pattern to be transferred to a molded product, a mirror surface block provided on the movable die so as to face the stamper, and a slide on the outer periphery of the mirror surface block. In a mold that produces a molded product by injecting molten resin while cooling and solidifying it while venting the gas in the cavity formed by the freely provided outer ring with the vent clearance formed by the stamper and outer ring And a sliding drive mechanism for moving the outer ring forward and backward in the direction of the fixed mold, and the sliding drive mechanism extends the vent clearance by retracting the outer ring in the process of taking out the molded product. It is characterized by.

  A second molding die of the present invention includes a stamper provided on a fixed die and having a relief pattern to be transferred to a molded product, a mirror block provided on the movable die so as to face the stamper, and an outer peripheral portion of the mirror block. Molding is performed by injecting molten resin while cooling and solidifying while exhausting the gas in the cavity formed by the outer ring that is slidably mounted in the vent clearance formed by the stamper and outer ring. In the mold, the outer peripheral ring is divided into two in the radial direction, and has a first outer peripheral ring on the inner peripheral side and a second outer peripheral ring on the outer peripheral side which are slidable with respect to each other. (2) The forward / backward movement of the outer peripheral ring with respect to the fixed mold direction differs depending on the actuator provided between the outer peripheral end lower surface of the first outer peripheral ring and the inner peripheral end lower surface of the second outer peripheral ring and the movable mold body. That in conjunction with the direction, the actuator is a take-out process of a molded article to advance the second peripheral ring, to retract the first peripheral ring, characterized in that for enlarging the vent clearance.

  In addition, the actuator has a pressure transmission means incorporating a working oil mixed with a thickener, or an elastic body containing a working oil mixed with a thickener.

  The molded product of the present invention is characterized by being manufactured by the molding die.

  The information recording medium of the present invention is characterized by being manufactured from the molded product.

  This invention is formed of resin that has flowed into the vent clearance by retreating the outer ring that forms the vent clearance with the stamper in the process of taking out the molded article, expanding the vent clearance, and then opening the mold. Since the mold is opened without applying a bending force to the burr, the molded product can be taken out without deforming the burr formed along the surface to which the relief pattern of the molded product is transferred.

  In addition, by setting the retraction amount of the outer ring less than the thickness of the molded product, the molded product can be stably held by the outer ring even when the molding die is completely opened. There is no need for problems such as defective picking.

  Furthermore, since the outer peripheral ring is retracted by the sliding drive mechanism in the process of taking out the molded product, the outer peripheral ring can be stably retracted and the amount of retraction can be accurately controlled.

  In addition, the outer peripheral ring is configured by a first outer peripheral ring on the inner peripheral side and a second outer peripheral ring on the outer peripheral side which are divided into two in the radial direction, and the first outer peripheral ring and the second outer peripheral ring move forward and backward with respect to the fixed mold direction. Actuators that operate in different directions move the second outer ring forward in the process of removing the molded product and retract the first outer ring to expand the vent clearance. The vent clearance can be expanded in the process.

  This actuator has pressure transmission means containing hydraulic oil mixed with a thickener, or has an elastic body containing hydraulic oil mixed with a thickener, so that the first outer ring and the second outer ring advance. -The backward movement can be easily performed in different directions.

  In addition, the molded product produced with this molding die can be taken out without deforming the burrs formed along the surface to which the relief pattern of the molded product is transferred, and stress due to unnecessary deformation at the outer peripheral edge. Good quality can be obtained up to the outer peripheral edge without being added.

  Furthermore, the information recording medium produced by this molded product has uniform quality in all areas and can improve reliability.

FIG. 1 is a partial cross-sectional view showing the configuration of the molding die of the present invention. A molding die 1 shown in the figure is for molding a disk substrate, for example, and has a fixed die 2 and a movable die 3, and a relief pattern to be transferred to the disk substrate is formed on the surface of the fixed die 2. A stamper 4 is provided. The movable mold 3 includes a mirror block 6 placed on the movable mold body 5, an outer ring 7 provided on the outer periphery of the mirror block 6, and a sliding drive mechanism 8 that holds the outer ring 7. The outer peripheral ring support member 9 is provided on the outer peripheral portion of the outer peripheral ring 7. The outer peripheral ring 7 is held by a sliding drive mechanism 8 embedded in the outer edge of the movable mold body 4 so as to be able to move back and forth in the direction of the fixed mold 2, and the inner peripheral surface is the outer peripheral end surface of the mirror block 6. However, the forward limit is restricted by the outer peripheral ring support member 9 provided on the outer peripheral portion. The sliding drive mechanism 8 has, for example, a hydraulic or pneumatic cylinder, and applies a forward force to the outer peripheral ring 7 in the direction of the fixed mold 2 except when the mold opening operation is performed in the molding process. The outer ring 7 is moved backward when the mold opening operation is performed. The forward force applied to the outer ring 7 by the sliding drive mechanism 8 is set to be smaller than the clamping force. The outer periphery of the fixed mold 2 has an abutting member 11 that engages with the movable ring 7.

  A molding method for molding a disk substrate with the molding die 1 will be described with reference to the process diagram of FIG. When the molding process starts and the movable mold 3 moves forward, as shown in FIG. 2A, the tip of the outer ring 7 whose forward limit is regulated by the outer ring support member 9 is pushed by the fixed mold 2. Contact the contact member 11. Further, when the movable mold 3 is advanced, the forward force applied to the outer ring 7 by the sliding drive mechanism 8 is set to be smaller than the mold clamping force, so that as shown in FIG. Moves backward relative to the moving movable mold body 5 to form a predetermined vent clearance 12 with the stamper 4. In this state, the cavity 13 is filled with molten resin, and even if the movable mold body 5 is slightly retracted due to the internal pressure of the cavity, the outer ring 7 is abutted by the advancing force applied from the sliding drive mechanism 8. The vent clearance 12 is maintained at a constant interval without moving backward while maintaining contact with the member 11. When the filling of the molten resin further proceeds, the molten resin flows into the vent clearance 12, and the resin that has flowed into the vent clearance 12 from the latter half of the filling process to the cooling process leads to the outer peripheral edge of the molded substrate 14 along the surface of the substrate 14. A horizontal burr 15 is generated.

  When the cooling process is completed and the process proceeds to the mold opening operation, as shown in FIG. 2C, the sliding drive mechanism unit 8 moves the outer ring 7 backward by a certain amount in the anti-cavity direction based on the control signal of the molding machine. Specifically, with reference to the signal for starting the mold opening operation, the backward movement of the sliding drive mechanism unit 8 is started a predetermined time before that time. Further, the retraction amount of the outer ring 7 by the sliding drive mechanism 8 is set to a value smaller than the plate thickness of the molded substrate 14. After the outer peripheral ring 7 is retracted, the movable mold body 5 is retracted. When the movable mold body 4 is retracted, the outer peripheral ring 7 is also retracted together with the molded substrate 14, and the mold opening is completed. When the mold opening operation is started in this manner, the outer peripheral ring 7 is retracted by a certain amount and separated from the lower part of the formed burr 15, and then the outer periphery together with the molded substrate 14 as shown in FIG. Since the ring 7 is also retracted, the substrate 14 can be taken out without applying any force in the cavity direction to the burr 15 formed on the outer peripheral end of the molded substrate 14, and is perpendicular to the molded substrate 14. Formation of burrs can be prevented. Further, since the retraction amount of the outer ring 7 is smaller than the thickness of the molded substrate 14, the molded substrate 14 is stabilized by the outer ring 7 even when the molding die 1 is completely opened as shown in FIG. In the continuous molding, problems such as defective take-out of the molded substrate 14 can be avoided.

  In the substrate 1 formed in this way, as shown in FIG. 3A, the burrs 15 are formed in a horizontal direction along the surface of the substrate 14 to which the relief pattern of the stamper 4 is transferred. 3B, a protective film 16 is formed on the surface of the substrate 14 having the burrs 15, and the protective film 16 side of the two substrates 14 is bonded to the adhesive as shown in FIG. 3C. Even if they are bonded together at 17, it is possible to produce a high-quality optical disk 18 in which the outer peripheral portion is not warped. Therefore, the optical disk 18 produced by laminating the disk substrate molded by the molding die 1 does not cause defects in the outer peripheral portion, has good quality in all regions, and has excellent long-term reliability. An information recording medium can be obtained.

  In the above description, the molding die 1 provided with the sliding drive mechanism 8 for moving the outer ring 7 forward and backward in the movable die 3 has been described. Next, the movable die 3 does not have the sliding drive mechanism 8. The second molding die will be described.

  FIG. 4 is a partial cross-sectional view showing the configuration of the second molding die. In the second molding die 1 a, the outer peripheral ring 7 of the movable mold 3 is divided into two in the radial direction, and the inner peripheral surface of the first outer peripheral ring 7 a on the inner peripheral side is a bearing 10 with respect to the outer peripheral end surface of the mirror block 6. The movable mold body 5 side is always supported by an elastic support 19 such as a compression spring or a bellows provided between the flange portion provided at the lower portion and the lower end of the outer peripheral end of the mirror block 6. A force for sliding in the anti-cavity direction (retreat side) is applied. The second outer peripheral ring 7b on the outer peripheral side has an inner peripheral surface that is slidable with respect to the outer peripheral surface of the first outer peripheral ring 7a via a bearing 20, and a compression spring or bellows embedded in the movable mold body 5 A force that slides in the cavity direction (forward direction) is always applied, and the forward limit is restricted by the outer ring support member 9. Between the outer peripheral end lower surface of the first outer peripheral ring 7 a and the inner peripheral end lower surface of the second outer peripheral ring 7 b and the movable mold body 5, hydraulic oil mixed with a thickener with an elastic material such as rubber having pressure resistance is mixed. It has a coated elastic actuator 22.

  A molding method for molding the disk substrate with the molding die 1a will be described with reference to the process diagram of FIG. When the molding process starts and the movable mold 3 moves forward, as shown in FIG. 5A, the tip of the second outer ring 7 b whose forward limit is regulated by the outer ring support member 9 is fixed mold 2. The butting member 11 is contacted. Further, when the movable mold 3 is advanced, the applying force of the elastic support 21 that applies the sliding force to the second outer peripheral ring 7b is set to be smaller than the mold clamping force, so that the outer peripheral ring 7 moves forward. Retreat relative to the mold body 5. The portion of the elastic actuator 22 that is in contact with the second outer peripheral ring 7b is compressed and deformed by the backward movement of the second outer peripheral ring 7b. When the portion of the elastic actuator 22 that is in contact with the second outer peripheral ring 7b is deformed, the portion of the elastic actuator 22 that is in contact with the first outer peripheral ring 7a is expanded by the action of the hydraulic oil contained therein, and this expansion force is applied to the first outer peripheral ring. If it becomes larger than the compressive force of the elastic support body 19 installed between 7a and the mirror surface block 6, the 1st outer periphery ring 7a will be advanced to the cavity side. When the advancement of the movable mold 3 is completed and the fixed mold 2 is fitted, the cavity side end surface of the first outer peripheral ring 7 a forms a predetermined vent clearance 12 with the surface of the stamper 4 of the fixed mold 2. In this state, the molten resin 23 is filled into the cavity 13 as shown in FIG.

  When the molten resin 23 is filled in the cavity 13 and the movable mold 3 is retracted by a minute distance due to the internal pressure of the molten resin 23, the second outer peripheral ring 7 b is moved by the forward force applied by the elastic support 21. It moves forward relative to the mold body 5 and maintains contact with the abutting member 11. At this time, the compressive force applied to the elastic actuator 22 from the second outer ring 7b is reduced, but the elastic actuator 22 is restored to a stable shape because the thickener is mixed in the internal hydraulic oil and the viscosity is increased. In this case, there is a certain delay until the first outer ring 7a is pressed, and the vent clearance 12 formed by the first outer ring 7a is prevented from expanding. Thus, since the normal injection filling is completed in about 1/10 second, the time for holding the state in which the first outer peripheral ring 7a is pressed by the elastic actuator 22 is not a problem as long as this time is sufficient. The time required for the elastic actuator 22 to restore its shape can be set to an arbitrary response time by appropriately selecting a thickener mixed in the built-in hydraulic oil and varying the viscosity of the hydraulic oil.

  The molten resin 23 filled in the cavity 13 flows into the vent clearance 12, and the resin flowing into the vent clearance 12 from the latter half of the filling process to the cooling process causes the outer peripheral edge of the molded substrate 14 as shown in FIG. Then, a horizontal burr 15 along the surface of the substrate 14 is generated. When the cooling process is completed and the mold opening operation is started and the movable mold 3 starts to retreat and the fixed mold 2 and the movable mold 3 start to separate, the second outer peripheral ring 7b is provided by the elastic support 21. The advancing force that moves forward relative to the movable mold body 5 eliminates the compressive force applied to the elastic actuator 22 from the second outer ring 7b, and the elastic actuator 22 gradually restores its shape to a predetermined response time. To restore a stable shape. When the shape of the elastic actuator 22 is gradually restored, the pressing force applied to the first outer ring 7a becomes smaller. When this pressing force becomes smaller than the elastic force of the elastic support 19, the first outer ring 7a moves backward in the anti-cavity direction. The burr 15 thus formed is separated from the lower part. Further, the mold opening operation proceeds, and as shown in FIG. 5E, the fixed mold 2 and the movable mold 3 are completely separated, and the position of the second outer ring 7b is restricted by the outer ring support member 9. Then, the elastic actuator 22 and the first outer ring 7a are restored to the state before the molding process is started.

  When the mold opening operation is started in this manner, the first outer ring 7 a is retracted using the elastic deformation of the elastic actuator 22, and the first outer ring 7 a is separated from the horizontal burr 15 along the surface of the substrate 14. During the mold opening operation, the substrate 14 can be taken out by performing mold opening without applying a deformation force to the burr 15. Further, since the retraction amount of the first outer ring 7a is less than the thickness of the molded substrate 14, the molded substrate 14 can be stably held in the molding die 1a even when the molding die 1a is completely opened. In the continuous molding, problems such as defective removal of the molded substrate 14 can be avoided. Therefore, the information recording medium produced by laminating the disk substrate molded with the molding die 1a does not cause defects in the outer peripheral portion, has good quality in all areas, and has excellent long-term reliability. A recording medium can be obtained.

  In the above description, the case where the elastic actuator 22 is formed of an elastic material such as rubber having pressure resistance and containing hydraulic oil mixed with a thickener has been described. However, as shown in FIG. The elastic actuator 22 may be formed by pressure transmission means including a cylinder 24 containing the hydraulic fluid and two sets of pistons 25.

  In the above description, the case where the disk substrate is formed has been described. However, optical elements such as an optical lens and various mechanical parts can be formed in the same manner.

It is a fragmentary sectional view which shows the structure of the shaping die of this invention. It is process drawing which shows the shaping | molding method by a shaping die. It is sectional drawing which shows the optical disk which bonded two board | substrates. It is a fragmentary sectional view which shows the structure of a 2nd shaping die. It is process drawing which shows the shaping | molding method by a 2nd shaping die. It is a block diagram of a 2nd elastic actuator. It is sectional drawing which shows the conventional two board | substrate and the optical disk which bonded it together. It is a fragmentary sectional view which shows the structure of the conventional molding die. It is process drawing which shows the shaping | molding method by a 2nd shaping die.

Explanation of symbols

1; molding die, 2; fixed die, 3; movable die, 4; stamper, 5; movable die body,
6; mirror block, 7; outer ring, 7a; first outer ring,
7b; second outer ring, 8; sliding drive mechanism, 9; outer ring support member,
10; bearing, 11; butting member, 12; vent clearance,
13; cavity, 14; substrate, 15; burr, 16; protective film, 17; adhesive,
18; optical disc, 19; elastic support, 20; bearing, 21; elastic support,
22: Elastic actuator.

Claims (8)

A stamper provided on a fixed mold and having a relief pattern to be transferred to a molded product; a mirror block provided on a movable mold facing the stamper; and an outer peripheral ring slidably provided on an outer peripheral portion of the mirror block; In the molding method to produce a molded product by injecting molten resin while exhausting the gas in the cavity formed by the vent clearance formed by the stamper and the outer ring and cooling and solidifying,
In the process of taking out the molded product, the mold opening is started after the outer peripheral ring is moved backward to enlarge the vent clearance.   The molding method according to claim 1, wherein the retraction amount of the outer peripheral ring is less than the thickness of the molded product. A stamper provided on a fixed mold and having a relief pattern to be transferred to a molded product; a mirror block provided on a movable mold facing the stamper; and an outer peripheral ring slidably provided on an outer peripheral portion of the mirror block; In a mold that produces a molded product by injecting molten resin while cooling and solidifying while venting the gas in the cavity formed by the vent clearance formed by the stamper and the outer ring,
A sliding drive mechanism that moves the outer ring forward and backward in the direction of the fixed mold, and the sliding drive mechanism extends the vent clearance by retracting the outer ring in the process of taking out the molded product; Mold characterized by A stamper provided on a fixed mold and having a relief pattern to be transferred to a molded product; a mirror block provided on a movable mold facing the stamper; and an outer peripheral ring slidably provided on an outer peripheral portion of the mirror block; In a mold that produces a molded product by injecting molten resin while cooling and solidifying while venting the gas in the cavity formed by the vent clearance formed by the stamper and the outer ring,
The outer peripheral ring is divided into two in the radial direction, and has a first outer peripheral ring on the inner peripheral side and a second outer peripheral ring on the outer peripheral side which are slidable with respect to each other, and the first outer peripheral ring and the second outer peripheral ring The forward / backward movement with respect to the fixed mold direction is performed in conjunction with different directions by actuators provided between the lower surface of the outer peripheral end of the first outer ring and the lower surface of the inner peripheral end of the second outer ring and the movable mold body. The molding die, wherein the actuator advances the second outer peripheral ring in the process of taking out the molded product, and retracts the first outer peripheral ring to enlarge the vent clearance.   The molding die according to claim 4, wherein the actuator has a pressure transmission means containing hydraulic oil mixed with a thickener.   The molding die according to claim 4, wherein the actuator has an elastic body containing hydraulic oil mixed with a thickener.   A molded article produced by the molding die according to any one of claims 3 to 6.   An information recording medium produced by the molded product according to claim 7.

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