JP5169495B2 - Compression molding die and compression molding apparatus - Google Patents

Description

  The present invention relates to a compression molding die and a compression molding apparatus capable of changing a cavity volume in accordance with a volume change when a molten synthetic resin, that is, a molten resin solidifies.

As containers for beverages and the like, synthetic resin containers made of a synthetic resin such as polyethylene terephthalate (PET) are widely used in practice. Such a synthetic resin container generally has a mouth-and-neck portion including a ring-shaped mouth portion and a ring-shaped support ring located at the lower portion of the mouth portion, and a bottomed cylindrical blow-molded portion depending from the mouth-and-neck portion. Is produced by molding a preformed body (preform) consisting of the following, and then blow-molding or stretch-blowing the blow-molded portion of the preformed body.
In order to form the preform, methods by injection molding or compression molding are known. Among these, in an example of a molding method using a compression molding apparatus, a molten synthetic resin (; molten resin) extruded from an extrusion opening of an extruder is cut with a cutter, and the cut molten resin (drop) is gripped. Is conveyed to the resin supply area of the compression molding machine. In the resin supply area, the female mold having the cavity opening is conveyed upward, and the synthetic resin is poured into the cavity in time for the timing when the gripping means is disposed immediately above the female mold. Next, the holding means is separated from the female mold, the male mold formed with the core facing downward is lowered from the upper position, the male mold and the female mold are closed, and the molten resin in the cavity is compression-molded and pre-molded The body is molded. After the preform is cooled, the compression mold is opened and the preform is removed from the mold.

The following Patent Document 1 discloses a structure in which an input member is disposed at the bottom of a cavity and the input member operates during compression molding of a resin, although the object is different from that of the present invention.
JP 2002-321273 A JP 2003-159739 A

As described above, in the state where the pre-molded body is compression-molded by the male mold and the female mold, the molten resin is gradually solidified. Synthetic resin in the process of solidifying from the molten state, the volume is reduced, with the polyethylene terephthalate, for example, resin density is 1.34 g / cm ³ at the time of solidification from 1.12 g / cm ³ in the molten state. Therefore, in the cavity, the mouth-and-neck portion of the pre-molded body has become an elliptical shape or the bottom portion is distorted as the synthetic resin volume decreases.
In the above-mentioned Patent Document 2, in the solidification process at a low temperature, as a part that does not affect the dimensions of the pre-molded body with respect to the occurrence of distortion based on the volume shrinkage of the molten resin due to the decrease in the resin temperature, the support of the pre-molded body is supported. An annular small protrusion (or groove) that protrudes upward from the cavity mold is formed at the bottom of the ring (also referred to as a flange or neck ring). In the driven mold, a fitting portion corresponding to the outer peripheral shape of the small protrusion is formed, a compressive force is applied to the core mold, and meshing them causes the cavity to shrink in volume, thereby causing distortion. Loss or distortion was suppressed (FIG. 5 of Patent Document 2).
An object of the present invention is to provide a compression molding die and a compression molding apparatus corresponding to a volume reduction at the time of solidification of a synthetic resin melted by a method different from Patent Document 2.

In order to achieve the above object, the compression mold of the present invention includes a female mold having an inner hole opened upward, and the female mold by moving up and down relative to the female mold. And a male mold that forms a closed state that cooperates to define a molding space (cavity) and an open state that is spaced apart from the female mold, and the female mold includes an outer periphery of the molding space. A cavity body provided with an inner hole forming a surface, and an input member that forms an outer surface of the bottom of the molding space and can be moved up and down in the axial direction of the inner hole, and the male mold includes at least an inner part of the molding space. A core body that protrudes downward and forms a peripheral surface or an inner surface of the bottom; the input member includes a movable bottom that forms a bottom outer surface of the molding space; a rod connected to a lower portion of the movable bottom; and A pedestal provided in the middle of the rod, and the cavity book The rod of the input member passes through the lower portion of the inner hole of the inner hole, and a partition wall is formed between the movable bottom and the pedestal. The partition wall and the pedestal (intermediate pedestal) An intermediate spring is disposed between the input member and a lower portion of the input member is provided with a molding spring for urging the input member upward, and a lifting means for the molding spring is provided, and the cavity body is connected to the input member. And when the female mold and the male mold are in the closed state, the female mold is supported by the compression elastic force of the molding spring by the lifting means. By energizing the male mold, the molten resin disposed between the female mold and the male mold is compression-molded into a bottomed cylindrical body.
Further, the bottomed cylindrical body is a container pre-molded body provided with a mouth and neck portion having at least one of a screw portion or a flange portion, and the compression molding die further includes the molding space. The neck ring mold for forming the outer surface of the mouth neck portion is provided, and when the compression mold is in a closed state, it is assembled between the female mold and the male mold to define a molding space. At that time, around the cavity main body of the compression molding die, a lock ring provided with a substantially cylindrical fitting portion into which at least a part of the outer periphery of the neck ring die is fitted, the lock ring, A sliding cylinder that slides on the outer peripheral portion of the cavity body, and a regulating portion (bottom wall) that abuts a locking portion (bottom surface) formed on the cavity body and regulates the rising position of the sliding cylinder. The cavity body is provided with a spring seat portion (flange portion) formed at a lower portion of the sliding cylinder, and the lock ring is provided between the lower portion of the sliding cylinder and the spring seat portion. The lock ring spring is biased to the raised position, and the lock ring spring can restrict the lock ring to the raised position in a non-engaged state of the neck ring type and the lock ring.
The elevating means of the compression molding die is a cam mechanism of a follower and a guide cam connected to a lower part of the molding spring, and the follower (roller) is guided by the guide cam and The molding spring can be moved up and down.
The compression molding die is a molten resin at the time of solidification of the molten resin molded in the molding space at the time of compression molding by the female die and the male die by the intermediate spring, the molding spring and the cam mechanism. The movable bottom can be raised along the inner hole in correspondence with the volume decrease.
The input member of the compression molding die can be provided with a stopper for restricting the rising position of the input member, and the cavity main body can be provided with an engaging portion (base) for restricting the rise of the stopper.
The spring constant of the compression spring of the compression molding die is preferably larger than the spring constant of the intermediate spring.
Furthermore, it is preferable that the spring constant of the intermediate spring is larger than the spring constant of the lock ring spring.
In order to achieve the above object, the compression molding apparatus of the present invention is a compression molding apparatus comprising a compression mold having a molding space and a molten resin carrying means for supplying molten resin to the cavity. It is comprised from the compression mold which has.

  The compression molding die of the compression molding apparatus according to the present invention has an input member provided with a movable bottom that forms an inner surface that forms an outer peripheral surface of a cavity in a female die, and that forms a bottom outer surface of the cavity at a lower portion of the inner hole. By raising and lowering the input member, the volume of the cavity can be reduced by raising the movable bottom when the molten resin is solidified and the volume is reduced during compression molding of the molten resin. Therefore, by pushing up the movable bottom by the decrease in the volume of the cavity, the mouth and neck of the preformed body becomes elliptical, and distortion such as wrinkles occurs at the lower part (tip) of the preformed body. It can be prevented or suppressed.

Hereinafter, a compression mold according to an embodiment of the present invention and a compression molding apparatus including the same will be described with reference to the drawings.
FIG. 1 is a schematic plan view of a compression molding apparatus according to the present invention, and FIG. 2 is a partially enlarged plan view showing a part of the compression molding apparatus of FIG.
The compression molding apparatus 1 includes an extruder 2, a synthetic resin supply device 3, a compression molding machine 4, and a carry-out device 5.
The extruder 2 has a substantially cylindrical outer shape, and heats, melts and kneads a synthetic resin material such as PP and PET to generate a molten resin. The front end side of the extruder 2 includes an extrusion nozzle 7 that is rotatably mounted between a set angle between a non-operation position indicated by a solid line and an operation position indicated by a two-dot chain line. The extrusion nozzle 7 is formed with a resin flow path extending to the extrusion opening shown in FIG. That is, the extruder 2 continuously sends the molten synthetic resin to the extrusion nozzle 7, and the synthetic resin sent from the extruder 2 is pushed out from the extrusion opening 20. When the compression molding apparatus 1 is in operation, the extrusion nozzle 7 is on standby at the operating position indicated by the two-dot chain line in FIG.

  The synthetic resin supply device 3 includes a rotating disk 11 that is driven to rotate in a direction indicated by an arrow a. A plurality of cutting / holding units 14 are arranged on the periphery of the rotating disk 11 at equal intervals in the circumferential direction. In accordance with the rotation of the rotating disk 11, the cutting / holding unit 14 is transported along a circular transport path extending along the periphery of the rotating disk 11. In the circular conveyance path, a synthetic resin receiving area 18 that faces the extrusion opening 20 of the extrusion nozzle 7 and is located immediately below it, and a resin supply area 21 that supplies the synthetic resin to the female mold 41 of the compression molding apparatus 4. Is provided.

  When the description is continued with reference to FIG. 3 together with FIG. 2, each of the cutting / holding units 14 includes a cutter 17, a first clamping member 15, and a second clamping member 16. The first clamping member 15 and the second clamping member 16 cooperate to define a receiving space in which the upper surface and the lower surface are opened together with the front surface in the movement direction. The second clamping member 16 is appropriately positioned between an open position separated from the first clamping member 15 shown in A of FIG. 3 and a clamping position approaching the first clamping member 15 shown in B of FIG. Can move.

4 is a front view of a male mold and a female mold of a compression mold, FIG. 5 is an exploded front view of the male mold, and FIG. 6 is an exploded front view of the female mold.
The compression mold includes a male mold 31, a female mold 41, and a molding spring 42 that supports the female mold 41.
For convenience of explanation, the neck ring mold 32 belongs to the male mold 31 side in the following explanation, but may be considered to be independent.
As shown in FIG. 5, the male die 31 is provided with a neck ring die 32 and a core 33. The neck ring 32 die can be separated and is composed of a pair of left and right neck ring halves 32a and 32b. ing. When the neck ring mold 32 is integrated, the neck ring mold 32 is an annular body in which a through hole 34 penetrating in the vertical direction is formed at the center of the neck ring mold 32, and has a separation surface passing through the central axis of the through hole 34. . In a state where the neck ring mold 32 is separated, the neck ring halves 32a and 32b are separated outward in the horizontal direction.

  The through-hole 34 of the neck ring mold 32 is formed with a core fitting portion 34a whose diameter is reduced in a tapered shape from the upper side to the lower side on the upper end side. It has a molding portion 34b that forms the outer surface of the neck and the support ring (or a top surface as necessary). A step hole 34c is formed in the lower portion of the molding portion 34b to be fitted into an annular protrusion 49 of the cavity main body 43 of the female mold 41 described later. A tapered surface 32 c is formed on the outer peripheral surface of the neck ring mold 32 so that the diameter of the lower end side decreases toward the lower side. In the present embodiment, the neck ring mold 32 has a truncated cone shape.

The core 33 includes a support body 36 and a core body 37, and the core body 37 projects downward from the bottom surface of the support body 36. The core body 37 has a substantially cylindrical shape, and the tip end on the lower end side is formed in a substantially semispherical shape, and the inner surface of the pre-molded body (in addition to the neck ring mold 32, the top surface as necessary). Form.
In the present embodiment, the core 33 is disposed at a stationary position, and the neck ring mold 32 is configured to be able to move up and down with respect to the core 33 by lifting means (not shown). The central axis of the core main body 37 and the central axis of the through hole 34 are arranged on the same axis, the core main body 37 is inserted into the through hole 34, and the support 36 of the core 33 is located at the raised position of the neck ring mold 32. The core fitting portion 34a of the through hole 34 is fitted, and the neck ring mold 32 and the core 33 are integrated.

  4 and 6, the female die 41 includes a cavity main body 43, a lock ring 44, and an input member 45. The cavity main body 43 includes a molding part 46 and a base part 55. In the cavity main body 43, an inner hole 47 is formed on the upper side of the central part and extends downward from the upper surface side of the cavity main body 43, and a partition wall 48 is formed in the bottom of the inner hole 47. The cylindrical inner hole 47 forms a part of the cavity (the outer surface of the blow molded part mainly of the preformed body, the outer peripheral surface of the body part below the mouth-neck part and above the bottom part). An annular protruding portion 49 that protrudes upward from the upper surface of the cavity body 43 is formed. The annular protrusion 49 is fitted with the step hole 34c of the neck ring mold 32 described above. The annular protrusion 49 and the stepped hole 34c can be omitted depending on how to divide the neck ring mold 32 and the cavity main body 43, and in this case, a conventional injection mold for a preformed body is omitted. And the same division position.

The partition wall 48 is formed with an insertion hole 52 having a smaller diameter than the inner hole 47 through which the intermediate rod 68 of the input member 45 is passed. An accommodation hole 51 having a diameter larger than that of the insertion hole 52 is formed below the insertion hole 52, and the intermediate spring 50 is accommodated in the accommodation hole 51.
In the cavity main body 43, the molding part 46 and the base part 55 are arranged with a space therebetween, and these are connected by a plurality of leg parts 54. That is, the upper end of the leg portion 54 is attached to the bottom surface of the molding portion 46, and the lower end of the leg portion 54 is attached to the upper surface of the base portion 55. The base portion 55 is formed with a flange portion 61 that protrudes outward from the leg portion 54.
On the upper surface in the vicinity of both ends of the flange portion 61, there are provided protrusions that prevent lateral movement when a lock ring spring 62 described later is assembled.
In addition, it is preferable that the flange portion 61 or the molding portion 46 can be appropriately removed / attached from the leg portion 54 when the lock ring 44 described later is assembled.
An insertion hole 56 through which the lower rod 70 of the input member 45 passes is formed at the center of the base portion 55. The inner hole 47, the accommodation hole 51, and the insertion holes 52 and 56 are disposed on the same axis.

The molding part 46 of the cavity main body 43 is accommodated in the lock ring 44 which is a cylindrical body. The lock ring 44 includes a sliding cylinder 58 and a bottom wall 59 provided at the lower portion of the sliding cylinder 58. The sliding cylinder 58 is fitted into the molding part 46 of the cavity main body 43, and the inner peripheral surface of the sliding cylinder 58 and the outer peripheral surface of the molding part 46 are in a slidable relationship.
A substantially cylindrical fitting portion 60 is formed on the upper portion of the sliding cylinder 58. A lock surface 60a is formed on the inner peripheral surface of the fitting portion 60. In the present embodiment, the lock surface 60a is a tapered surface that decreases downward inward in the radial direction in accordance with the outer peripheral surface of the neck ring mold 32. is there. When the female die 41 is raised, the lock surface 60a is fitted to the lower end of the tapered surface 32c of the neck ring die 32 to prevent the neck ring die 32 from entering further downward, and the neck ring half 32a. , 32b is strengthened.

The bottom wall 59 of the lock ring 44 is disposed between the molding portion 46 and the base portion 55. Through holes 64 are formed in the bottom wall 59 of the lock ring 44 at positions corresponding to the respective leg portions 54 of the cavity main body 43, and the leg portions 54 are passed through the through holes 64. The outer peripheral surface of the leg portion 54 and the inner peripheral surface of the through hole 64 are in a sliding relationship. When the bottom wall 59 comes into contact with the bottom surface 46 a of the molding portion 46, the bottom wall 59 serves as a stopper. The rising position is restricted, and at this position, the lock surface 60 a of the fitting portion 60 protrudes from the upper surface of the molding portion 46.
A concave groove 65 is formed on the upper surface side in the central portion of the bottom wall 59, and a bottom hole 66 through which the lower rod 70 of the input member 45 passes is formed in the central portion of the concave groove 65. The concave groove 65 can be omitted as appropriate, and only the bottom hole 66 may be formed.

The input member 45 includes a movable bottom 67, an intermediate rod 68, an intermediate pedestal 69, a lower rod 70, and a base 71.
The movable bottom 67 is slidably disposed in the inner hole 47 of the cavity main body 43, and an upper surface formed in a substantially semispherical surface forms the bottom of the cavity. The flat plate-shaped intermediate pedestal 69 is connected between the intermediate rod 68 and the lower rod 70 and is accommodated in a concave groove 65 formed in the bottom wall 59 of the lock ring 44, and is accommodated in the cavity main body 43. Any size that can be inserted through 51 is acceptable. As described above, the intermediate rod 68 passes through the insertion hole 52 of the partition wall 48, and the lower rod 70 passes through the bottom hole 66 of the lock ring 44 and the insertion hole 56 of the cavity body 43.
A flat plate-like base 71 is connected to the lower portion of the lower rod 70, and a stopper 72 protruding upward from the upper surface is formed on the upper surface of the base 71. The stopper 72 plays a role of regulating the rising position of the movable bottom 67.
It is also possible to omit the stopper 72 and play the role of the base 71. In addition, when the input member 45 is assembled to the cavity main body 43 and the lock ring 44, the movable bottom 67, the intermediate pedestal 69, and the base 71 can be appropriately removed / attached from the intermediate rod 69 and the lower rod 70, respectively. It is preferable that

As shown in FIG. 4, a coil-shaped intermediate spring 50 is disposed in the accommodation hole 51 of the cavity main body 43. The intermediate spring 50 is disposed in a compressed state between the lower surface of the partition wall 48 that is the ceiling wall of the accommodation hole 51 and the upper surface of the intermediate portion base 69 of the input member 45. 45 intermediate rods 68 pass therethrough.
A pair of coil-shaped lock ring springs 62 are disposed in a compressed state between the lower surface of the bottom wall 59 of the lock ring 44 and the upper surface of the flange portion 61 of the cavity main body 43.
A coil-shaped molding spring 42 is disposed at the lower part of the base 71, the upper end of the molding spring 42 is attached to the bottom surface of the base 71, and the rolling element 74 is attached to the lower end.

The spring constants of the molding spring 42, the intermediate spring 50, and the lock ring spring 62 are the largest in the molding spring 42, and the smaller ones in the order of the intermediate spring 50 and the lock ring spring 62 (the spring constant including the pair of lock ring springs 62) are used. doing.
In addition, it is preferable to preload each spring as needed.
When the male mold 31 and the female mold 41 are in the open state, the intermediate spring 50 supports the load of the cavity body 43, urges the movable bottom 67 against the partition wall 48, and connects the intermediate pedestal 69 to the lock ring 44. The bottom surface of the concave groove 65 is urged. The lock ring spring 62 supports the lock ring 44 and urges the bottom wall 59 against the bottom surface of the molding portion 46. The molding spring 42 supports the entire female die 41 (hereinafter, this state is referred to as an initial state).
A guide cam 75 is provided below the rolling element 74. The guide cam 75 forms an inclined surface on the circular orbit of the female die 41, and the rolling element 74 is guided on the inclined surface and can move up and down on the circular orbit.
At that time, it is preferable that the female die 41 is guided so as not to move in the lateral direction.
The vertical movement of the rolling element 74 raises and lowers the female die 41, and the compression molding dies 31, 41 can be closed and compressed by narrowing the distance between the male die 31 and the female die 41. The male mold 31 and the female mold 41, which are compression molds, can be opened by widening the interval.

Next, the operation of the compression molding apparatus in the embodiment of the present invention will be described.
1 to 3, the extruder 2 heats and melts and kneads a synthetic resin material such as polyethylene terephthalate, and conveys the molten synthetic resin, that is, the molten resin 8 to the extrusion nozzle 7. The molten resin 8 extruded from the extrusion opening 20 of the extrusion nozzle 7 is cut by the cutter 17 in the molten resin receiving area 18 and separated from the extrusion opening 20. When the molten resin 8 is cut off, the molten resin 8 is held by closing the first and second holding members 15 and 16 (B in FIG. 3). The molten resin 8 held by the cutting / holding unit 14 is moved to a position immediately above the female mold 23 in the resin supply area 21 of the compression molding machine 4 and is put into the cavity of the female mold 41.

In the compression molding machine 4, as shown in FIG. 7A, the rolling element 74 rolls obliquely upward on the inclined surface of the guide cam 75, and the male die 31 is positioned immediately above the female die 41. Thus, the same circular orbit as the female die 41 is moved. The female mold 41 maintains the initial state until it contacts the male mold 31. The initial state continues until the neck ring mold 32 and the fitting portion 60 abut.
As shown in FIG. 7B, the female die 41 is raised by the rolling element 74 being guided by the guide cam 75, and the fitting portion 60 of the lock ring 44 is connected to the tip (lower) end of the neck ring die 32. The lock ring spring 62 supports the weight of the neck ring mold 32 via the lock ring 44 and contracts by the load.
As the female die 41 is further raised, the annular protrusion 49 of the cavity main body 43 is fitted into the step hole 34c of the neck ring mold 32, and the neck ring mold 32 and the cavity main body 43 are in a coupled state. At this time, the intermediate spring 50 supports the weight of the neck ring mold 32 via the cavity body 43 and the lock ring spring 62 via the lock ring 44, but the spring constant of the intermediate spring 50 is larger. The lock ring spring 62 has a larger reduction ratio.

When the cavity main body 43 is further raised from this state, the core 33 is fitted into the neck ring mold 32 as shown in FIG. 7C, and the compression molding of the molten resin is performed in the cavity. At this time, since the movable bottom 67 is still located at the bottom dead center with respect to the molding portion 46, the molten resin 8 is formed at the upper end of the cavity that is the molding space (the neck ring mold 32, the front molding body forming surface of the core body 37. The upper edge is not reached.
When the input member 45 (movable bottom 67) is further raised from this state, the molten resin 8 fills the cavity as shown in FIG. 7D to FIG. 8B, and pressure holding is performed.
The clamping force for compression molding can be obtained by the compression of the molding spring 42 and the intermediate spring 50.
At the time of holding pressure, the intermediate spring 50 urges the bottom surface of the movable bottom 67 against the partition wall 48, and the intermediate spring 50 itself is pushed up by the intermediate base 69 of the input member 45 and gradually decreases. The molten resin 8 is cooled and solidified at the time of holding pressure, but volume condensation of the molten resin 8 occurs when solidified as described above. In accordance with the timing at this time, the inclined surface of the guide cam 75 is appropriately formed, and the input member 45 is raised, stopped, and lowered via the molding spring 42.
By raising the input member 45, the pushing force of the input member 45 of the molding spring 42 becomes larger than the urging force of the movable bottom 67 to the partition wall 48 by the intermediate spring 50, and the movable bottom 67 opens the inner hole 47. Slide upward. Then, the volume of the cavity becomes smaller and the decrease can be absorbed. The input member 45 is stopped for a predetermined time. Thus, by reducing the volume of the cavity, it is possible to prevent the mouth-and-neck portion from being deformed into an elliptical shape, and to form a preform without distortion such as wrinkles at the bottom.

Further, as shown in FIG. 8B, the stopper 72 contacts the bottom surface of the cavity body 43 when the input member 45 is lifted to prevent the input member 45 from being lifted. Thus, the molding force is released in the middle of compression molding, and the core body 37 and the movable bottom 67 are prevented from coming into contact with each other. It is also possible to set the bottom wall thickness of the pre-molded body to be molded by setting the height of the stopper. When using a different synthetic resin material to be molded and different rate of reduction at the time of solidification, the restriction position may be changed by finely adjusting or replacing the stopper.
As shown in FIG. 8C, the molds 31 and 41 are separated from the male mold 31 and the female mold 41 by forming a downwardly inclined surface on the guide cam 75. At this time, the input member 45 is pushed back downward by the intermediate spring 50. The pre-formed body is supported on the neck ring mold 32 side, and as shown in FIG. 8D, the pre-formed body can be taken out by opening the neck ring halves 32a and 32b outward in the horizontal direction.

The present invention has been described in detail based on the embodiments with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and other modifications can be made without departing from the scope of the present invention. Or it can be changed.
In the above embodiment, the rolling element 74 connected to the molding spring 42 is guided by the guide cam 75 to raise the female die 41 and the core 33 is arranged at the same height position. A rolling element may be attached to the upper end of 33, and the rolling element may be guided by a guide cam having an inclined surface. Further, without changing the position of the molding spring 42, a rolling element may be attached to the upper end portion of the core 33, and the rolling element may be guided by a guide cam that shakes the inclined surface, or the lower end of the molding spring 42 and the core 33. If the male mold 31 (including the neck ring mold 32) and the female mold 41 can be closed by relatively approaching the upper end of the member, any member that moves up and down can be used.
Further, in this embodiment, the rotary type (carousel type) compression molding apparatus 4 provided with a plurality of compression molding dies is used. After the supply to the inner hole 47, the lower end of the molding spring 42 and the upper end of the core 33 are relatively moved by a known actuator such as a servo motor or a lifting device using a combination of a known power source and mechanism such as a motor and a crank mechanism. You may make it approach and compression-mold.

In the present embodiment, the molding spring 42 has the largest spring constant of the molded spring 42, the intermediate spring 50, and the lock ring spring 62, and the intermediate spring 50 and the lock ring spring 62 (a spring constant including a pair of lock ring springs 62). ) In the order of (), but the order of the sizes may be changed depending on the preload setting of each spring. Similarly to the case where the lock ring spring 62 is provided in one or more (a pair), the molding spring 42, the intermediate spring 50, and the lock ring spring 62 may be provided in a plurality.
Furthermore, the molded object is not limited as long as the molten resin can be formed by compression molding. At that time, depending on the molded product, the neck ring mold 32, the lock ring 44, the lock ring spring 62, the flange portion 61, and the leg portion 54 may be omitted as appropriate, and a mold structure in which the remaining members are used as substitutes is appropriately adopted. Also good. For example, when the neck ring mold 32, the lock ring 44, the lock ring spring 62, the flange portion 61, and the leg portion 54 are omitted, the stopper 72 is used in contact with the bottom surface of the molding portion 46 instead of the flange portion 61 of the cavity body 43. .

It is a schematic plan view of the compression molding apparatus by embodiment of this invention. It is an enlarged plan view of the synthetic resin supply apparatus of the compression molding apparatus of FIG. 2A is a front view immediately before the cutting / holding unit of the synthetic resin supply apparatus of FIG. 2 receives the molten resin, and B is a front view of the state in which the molten resin is gripped. It is a front view of the compression molding die of the compression molding machine shown in FIG. FIG. 5 is an exploded front view of a male mold of the compression molding mold shown in FIG. 4. FIG. 5 is an exploded front view of a female mold of the compression molding mold shown in FIG. 4. FIG. 4 shows a compression molding process using a male mold and a female mold shown in FIG. 4, A is a front view of the initial state where the male mold and the female mold are released, and B is a state where the neck ring mold and the lock ring are in contact with each other. C is a front view of a state in which the male mold and the female mold are clamped in an initial state and the core presses the molten resin, and D is a movable bottom ascending to fill the molding space with the molten resin. It is a front view in the state where pressure keeping was started. FIG. 7 is a continuation of the compression molding process of FIG. 7, A is a front view of the state where the movable bottom of the input member is raised and the volume of the cavity is reduced, and B is the movable bottom of the input member is raised to the top dead center. The front view in a state where the compression molding is completed, C is a front view in a state where the male mold and the female mold are separated, and BD is a front view in a state where the neck half is divided and the pre-molded body is taken out. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compression molding apparatus 4 Compression molding machine 31 Male mold 32 Neck ring type 32a, 32b Neck ring half 33 Core 37 Core main body 41 Female mold 42 Molding spring 43 Cavity main body 44 Lock ring 45 Input member 46a Bottom surface (locking part)
47 Inner hole 48 Partition wall 50 Intermediate spring 59 Bottom wall (Regulator)
60 Fitting part 62 Lock ring spring 67 Movable bottom 69 Intermediate part base 71 Base 72 Stopper 74 Roller 75 Guide cam

Claims (8)

A compression mold for compressing a molten resin,
A female mold having an inner hole opened upward;
A closed state that defines a bottomed cylindrical molding space in cooperation with the female die by an up-and-down movement relative to the female die and an open state that is spaced apart from the female die. Comprising a male mold to constitute,
The female mold includes a cavity body provided with an inner hole that forms an outer peripheral surface of the molding space, and an input member that forms a bottom outer surface of the molding space and can be moved up and down in the axial direction of the inner hole,
The male mold includes a core body projecting downward, forming at least an inner peripheral surface or a bottom inner surface of the molding space,
The input member includes a movable bottom forming a bottom outer surface of the molding space, a rod connected to a lower portion of the movable bottom, and a pedestal provided at an intermediate portion of the rod,
Under the inner hole of the cavity body, the rod of the input member penetrates, and is positioned between the movable bottom and the pedestal to form a partition wall,
An intermediate spring is disposed between the partition wall and the pedestal, and a molding spring for biasing the input member upward is disposed at a lower portion of the input member, and a lifting means for the molding spring is provided.
When the cavity main body is supported by the molding spring via the input member and the intermediate spring, and the female mold and the male mold are in a closed state, the compression elastic force of the molding spring by the lifting means By energizing the female mold to the male mold, the molten resin disposed between the female mold and the male mold is compressed into a bottomed cylindrical body. Compression molding die characterized by. The bottomed cylindrical body is a preform of a container provided with a mouth and neck portion having at least one of a screw portion or a flange portion,
The compression molding die is further provided with a neck ring die for forming an outer surface of the mouth and neck of the molding space, and when the compression molding die is in a closed state, the female die and the male die Assemble between them, the molding space is defined,
Around the cavity body, a lock ring provided with a substantially cylindrical fitting portion into which at least a part of the outer periphery of the neck ring mold is fitted,
The lock ring slides on the outer peripheral portion of the cavity main body, and a slide cylinder in which the fitting portion is formed at an upper end portion;
A regulating portion that abuts on a locking portion formed in the cavity main body and regulates the rising position of the sliding cylinder;
The cavity body is provided with a spring seat portion formed at a lower portion of the sliding cylinder with a space therebetween, and the lock ring is urged to the raised position between the lower portion of the sliding cylinder and the spring seat portion. Provide a lock ring spring,
2. The compression molding die according to claim 1, wherein the lock ring spring is configured to restrict the lock ring to a raised position in a non-engaged state of the neck ring mold and the lock ring.   The elevating means is a cam mechanism of a follower and a guide cam connected to a lower portion of the molding spring, and the follower is guided by the guide cam to raise and lower the molding spring. The compression molding die according to claim 1 or 2, characterized by the above. By the intermediate spring, the molding spring and the cam mechanism,
The movable bottom is raised along the inner hole corresponding to the volume reduction of the molten resin when the molten resin molded in the molding space is solidified during compression molding by the female mold and the male mold. The compression mold according to claim 3, wherein the compression mold is used.   The input member is provided with a stopper for restricting the rising position of the input member, and the cavity body is provided with an engaging portion for restricting the stopper from being raised. 2. A compression mold according to claim 1.   The compression molding die according to any one of claims 1 to 5, wherein a spring constant of the molding spring is larger than a spring constant of the intermediate spring.     The compression molding die according to any one of claims 2 to 6, wherein a spring constant of the intermediate spring is larger than a spring constant of the lock ring spring. In a compression molding apparatus comprising a compression mold having a molding space and a molten resin carrying means for supplying a molten resin to the cavity,
A compression molding apparatus comprising the compression molding die according to any one of claims 1 to 7, wherein the compression molding die having the cavity.

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