JP4770265B2 - Melt polymerization / compression molding system - Google Patents

Description

  The present invention provides melt polymerization of a resin such as a thermoplastic polyester, and then compression molding the melt polymerized resin to give the required molded product, for example, a pre-molded body that is subsequently placed in a container by adding blow molding. -It relates to a compression molding system.

In Patent Document 1 below, a thermoplastic polyester is melt-polymerized, and the melt-polymerized resin is supplied as it is to an injection molding means without being cured, and then blow molded to give a preform (generally a preform). Which is also referred to as injection molding). Furthermore, it is also disclosed that the melt-polymerized resin is supplied not to the injection molding means but to the compression molding means and compression molded into the preform.
JP 2000-117819 A

  The supply of the resin to the compression molding means is conveniently performed by continuously discharging the resin from the required discharge port at the required pressure. The compression molding means conveniently applied to the compression molding of the pre-molded body includes a cutting / conveying mechanism together with a compression molding machine including a plurality of molding dies, and cuts the resin discharged from the discharge port one after another. Supply to mold in open state. From the standpoint of avoiding the generation of acetaldehyde as much as possible, it is desirable for melt-polymerized resin to be supplied by constantly flowing as short a path as possible, and therefore supplying the melt-polymerized resin to the compression molding means. In the case of compression molding into a required molded product, it is desirable to continuously discharge the melt-polymerized resin from the melt polymerization means and continuously supply the resin to the compression molding means without temporarily storing it in an accumulator or the like. .

  However, when the operation of the compression molding means is stopped due to the occurrence of trouble in the compression molding means, it is necessary to stop the resin supply to the compression molding means. On the other hand, the operation of the melt polymerization means usually needs to be continued without stopping. Therefore, when the operation of the compression molding means is stopped, the resin continuously discharged from the melt polymerization means can be effectively used without being wasted, and when the operation of the compression molding means is resumed, there is a delay. It is desirable that the continuous resin supply to the compression molding means can be resumed.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is that in addition to being able to continuously supply the resin continuously discharged from the melt polymerization means to the compression molding means, Even when the operation of the compression molding means is stopped while continuing the operation of the polymerization means, the resin continuously discharged from the melt polymerization means can be effectively used without being wasted, and the compression molding is performed. To provide a new and improved melt polymerization / compression molding system capable of resuming the continuous resin supply to the compression molding means immediately when the operation of the means is resumed.

  According to the present invention, the additional molding means which is not necessarily important to supply continuously at a predetermined pressure is attached, and the resin is appropriately supplied to the additional molding means in accordance with the fluctuation in the resin supply to the compression molding means. The main technical problem can be achieved by controlling to the above.

That is, according to the present invention, as a melt polymerization / compression molding system that achieves the main technical problems described above, a melt polymerization means, at least one compression molding means, and between the melt polymerization means and the compression molding means are arranged. In the melt polymerization / compression molding system comprising the main resin flow path and the operation control means,
First discharge means for continuously flowing out the resin from the melt polymerization means is disposed at the upstream end of the main resin flow path, and the first resin flow path is flowed through the main resin flow path at the downstream end of the main resin flow path. A second discharge means for continuously supplying the obtained resin to the compression molding means,
Furthermore, an additional molding means is provided, and a sub resin flow path is disposed between the branch portion of the main resin flow path and the additional molding means, and at the downstream end of the sub resin flow path. Discharge amount variable discharge means for supplying the resin flowed through the sub resin flow path to the additional molding means is disposed, and the discharge amount of the discharge amount variable discharge means is controlled by the operation control means.
A melt polymerization / compression molding system is provided.

  Preferably, pressure detection means for detecting a resin pressure in the main resin flow path is disposed at a pressure detection portion downstream of the branch portion, and the operation control means is a resin detected by the pressure detection means. The discharge amount of the discharge amount variable discharge means is controlled according to the pressure, and the pressure detected by the pressure detection means is kept constant. Conveniently, an on-off valve means is disposed downstream of the pressure detection site in the main resin flow path. In place of the pressure detection means and the detected resin pressure, the pressure detection means is arranged according to the operating state of the second discharge means, or between the branch portion of the main resin flow path and the second discharge means. The discharge amount of the discharge amount variable discharge means can be controlled according to the operating state of the open / close valve means. A plurality of compression molding means are provided, and a downstream portion of the main resin flow path is branched into a plurality of branch resin flow paths corresponding to each of the plurality of compression molding means. It is preferable that the opening / closing valve means and the second discharge means are disposed in each of the flow paths. The resin that is melt polymerized in the melt polymerization means is polyester, and the compression molding means may be a compression molding of a pre-molded body that is later put into a container by adding blow molding.

  In the melt polymerization / compression molding system of the present invention, the resin supply to the additional molding means can be appropriately controlled in accordance with the fluctuation in the resin supply to the compression molding means, and therefore the melt polymerization means continuously from the melt polymerization means. In addition to being able to continuously supply the resin discharged to the compression molding means, when the operation of the compression molding means is stopped while continuing the operation of the melt polymerization means, The resin discharged to the resin can be supplied to the additional molding means without being wasted and used effectively, and when the operation of the compression molding means is resumed, continuous resin supply to the compression molding means Can be resumed immediately.

  The preferred embodiment of a melt polymerization and compression molding system constructed in accordance with the present invention will now be described in further detail with reference to FIG.

  The illustrated melt polymerization / compression molding system constructed in accordance with the present invention comprises one melt polymerization means 2, four compression molding means 4a, 4b, 4c and 4d and one additional molding means 6. .

  The melt polymerization means 2 is composed of a well-known multistage melt polymerization apparatus which can melt polymerize a synthetic resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) in a continuous manner. It is convenient to be. Each of the compression molding means 4a, 4b, 4c, and 4d may be of a well-known form, and includes a compression molding machine having a plurality of compression molds arranged at intervals in the circumferential direction, and a discharge described later. It is advantageous to comprise a cutting / conveying mechanism that cuts the molten resin continuously discharged from the discharge port of the means, conveys it through a required path, and supplies it successively to each compression molding die of the compression molding machine. . Preferable forms of the compression molding machine and the cutting / conveying mechanism for attacking the compression molding means include those disclosed in Japanese Patent Application Laid-Open No. 2000-25729 or Japanese Patent Application Laid-Open No. 2000-108127. The compression molding machine compresses and molds a pre-molded body that can be put into a container by adding blow molding later. The additional molding means 6 may be a molding means of any form as long as it is a molding means in a form that does not need to continuously supply resin at a predetermined pressure and can appropriately change the resin supply state. The pelletizer may be formed from the supplied molten resin by a well-known pelletizer.

  Continuing with reference to FIG. 1, a main resin flow path generally indicated by numeral 8 is disposed between the melt polymerization means 2 and the compression molding means 4. The main resin flow path 8 is composed of four branch flow paths 12a, 12b, 12c and 12d corresponding to the common resin flow path 10 and the four compression molding means 4, respectively. The compression molding means 4a is connected to the melt polymerization means 2 via the common resin flow path 10 and the branch resin flow path 12a, and the compression molding means 4b is melt polymerization via the common resin flow path 10 and the branch resin flow path 12b. The compression molding means 4c is connected to the melt polymerization means 2 via the common resin flow path 10 and the branched resin flow path 12c, and the compression molding means 4d is connected to the common resin flow path 10 and the branched resin. It is connected to the melt polymerization means 2 through a flow path 12d.

  A first discharge means 14 is disposed at the upstream end of the main resin flow path 8, and hence at the upstream end of the common resin flow path 10. The discharge means 14, which is preferably composed of a gear pump, continuously discharges a molten resin, for example, a polyester resin melt-polymerized in the melt-polymerization means 2 from the melt-polymerization means 2. The common resin flow path 10 of the main resin flow path 8 is also provided with a pressure detection means 16 for detecting the pressure of the resin flowing therethrough.

  Second discharge means 18a, 18b, 18c and 18d are disposed at the downstream ends of the branch flow paths 12a, 12b, 12c and 12d of the main resin flow path 8, respectively. Such discharge means 18a, 18b, 18c and 18d can also be advantageously constructed from a gear pump, and the molten resin flowed through the branch flow paths 12a, 12b, 12c and 12d is continuously and quantitatively discharged to compress and form the compression means 4a. 4b, 4c and 4d. On / off valve means 20a, 20b, 20c and 20d, each of which can be constituted by an appropriate form of on-off valve member, are also disposed in each of the branch flow paths 12a, 12b, 12c and 12d.

  The branch portion 22 located between the position where the discharge means 14 is disposed in the common resin flow path 10 of the main resin flow path 8 and the position where the pressure detection means 16 is disposed, and the additional molding means 6. A sub-resin channel 24 is disposed between them. Discharge means 26 having a variable discharge amount is disposed at the downstream end of the sub resin flow path 24. It is preferable that the discharge means 26 is also composed of a gear pump whose discharge amount can be appropriately changed. The illustrated melt polymerization / compression molding system is further provided with an operation control means 28 for controlling the operation of the discharge means 26 in accordance with the pressure detected by the pressure detection means 16. Such operation control means 28 can be constituted by a microprocessor.

  The operation mode of the melt polymerization / compression molding system as described above is as follows. The melt polymerization means 2 is continuously operated, and continuously melt polymerizes a resin, for example, polyester. Then, the melt-polymerized resin is continuously discharged quantitatively by the discharge means 14. The amount that the discharge means 14 continuously discharges is preferably set larger than the total amount required by the four compression molding means 4a, 4b, 4c, and 4d by a predetermined amount. If desired, the amount of melt-polymerized resin present in the melt-polymerization means 2 is detected by an appropriate detection means (not shown) such as a liquid level detection means, and the discharge means according to the detected resin amount. It is also possible to appropriately control the operation of 14. The molten resin discharged from the discharge means 14 to be melt-polymerized is caused to flow through the common resin flow path 10 of the main resin flow path 8 and the branched resin flow paths 12a, 12b, 12c and 12d, and the discharge means 18a, 18b, 18c and 18d. Are continuously supplied to each of the compression molding means 4a, 4b, 4c and 4d.

  The molten resin discharged into the common resin flow path 10 of the main resin flow path 8 by the discharge means 14 is also caused to flow into the sub resin flow path 24. The operation of the discharge means 26 disposed in the sub resin flow path 24 is controlled according to the resin pressure in the common resin flow path 10 detected by the pressure detection means 16. More specifically, the operation of the discharge means 26 is controlled so that the resin pressure detected by the pressure detection means 16 is maintained at a predetermined value. Accordingly, when all of the compression molding means 4a, 4b, 4c and 4d are operating normally, the amount of resin consumed by the four compression molding means 4a, 4b, 4c and 4d from the amount of resin discharged by the discharge means 14 The amount of the resin obtained by subtracting is made to flow through the sub resin flow path 24 and supplied to the additional molding means 6 by the discharge means 26.

  On the other hand, for example, when a failure occurs in the compression molding means 4a and a repair is necessary, or when there is a need for inspection or a mold change in the compression molding means 4a, the branched resin flow in the main resin flow path 8 is reduced. The on-off valve means 20a disposed in the passage 12a is switched to the closed state and the operation of the discharge means 18a is stopped. The on-off valve means 20b, 20c and 20d are maintained in the open state, and the discharge means 18b, 18c and 18d continue to be operated, so that compression molding is continued in the compression molding means 4b, 4c and 4d.

  When the on-off valve means 20a in the branched resin flow path 12a is closed, the resin pressure in the common resin flow path 10 of the main resin flow path 8 is increased. Thus, the operation control means 28 increases the operation capacity of the discharge means 26 disposed in the sub resin flow path 24 and increases the discharge amount. As a result, the amount of molten resin supplied to the additional molding means 6 is increased by the amount of molten resin supplied to the compression molding means 4a. Accordingly, even if the operation of the melt polymerization means 2 is continued, the entire melt polymerization / compression molding system can continue to operate without causing any particular problems, and the melt polymerized resin is not wasted. .

  When restarting the operation of the compression molding means 4a, the on-off valve means 20a disposed in the branch resin flow path 12a is returned to the open state and the operation of the discharge means 18a is restarted to melt into the compression molding means 4a. Resin supply resumed. Thus, the resin pressure in the common resin flow path 10 of the main resin flow path 8 is reduced. Therefore, the operation control means 28 reduces the operation capacity of the discharge means 26 disposed in the sub resin flow path 24 to reduce the discharge amount. As a result, the amount of molten resin supplied to the additional molding means 6 is reduced by the amount of molten resin supplied to the compression molding means 4a. Thus, the operation of the compression molding means 4a can be resumed smoothly without causing problems in the entire melt polymerization / compression molding system.

  All the operations of not only the compression molding means 4a but also the compression molding means 4a, 4b, 4c and 4d are stopped, all the open / close control valves 20a, 20b, 20c and 20d are switched to the closed state, and the discharge means 18a, 18b, Even when all the operations of 18c and 18d are stopped, the operation of the discharge means 26 is controlled by the operation control means 28 without causing any particular inconvenience, and in this case, the main means from the melt polymerization means 2 is controlled by the discharge means 14. Substantially all of the resin discharged into the common resin flow path 10 of the resin flow path 8 is supplied to the additional molding means 6.

  In the embodiment described above, the operation control means 28 controls the operation of the discharge means 26 in accordance with the resin pressure detected by the pressure detection means 16, but if desired, instead of this, for example, the second discharge means 18a, 18b, 18c and 18d operating states (continuous quantitative discharge state or operation stop state) are detected by appropriate detecting means, and depending on the operating state of the second discharging means 18a, 18b, 18c and 18d, or open / close The operation state (open state or closed state) of the valve means 20a, 20b, 20c and 20d is detected by an appropriate detection means, and the operation of the discharge means 26 is performed according to the operation state of the on-off valve means 20a, 20b, 20c and 20d. Can also be controlled.

1 is a simplified diagram illustrating a preferred embodiment of a melt polymerization / compression molding system constructed in accordance with the present invention.

Explanation of symbols

2: Melt polymerization means 4a, 4b, 4c and 4d: Compression molding means 6: Additional molding means 8: Main resin flow path 10: Common resin flow path of main resin flow path 12a, 12b, 12c and 12d: Branched resin flow path 14: First discharge means 16: Pressure detection means 18a, 18b, 18c and 18d: Second discharge means 20a, 20b, 20c and 20d: On-off valve means 22: Branch portion 24: Sub resin flow path 26: Discharge amount Variable discharge means 28: Operation control means

Claims (9)

In a melt polymerization / compression molding system comprising a melt polymerization means, at least one compression molding means, a main resin flow path disposed between the melt polymerization means and the compression molding means, and an operation control means,
First discharge means for continuously flowing out the resin from the melt polymerization means is disposed at the upstream end of the main resin flow path, and the first resin flow path is flowed through the main resin flow path at the downstream end of the main resin flow path. A second discharge means for continuously supplying the obtained resin to the compression molding means,
Furthermore, an additional molding means is provided, and a sub resin flow path is disposed between the branch portion of the main resin flow path and the additional molding means, and at the downstream end of the sub resin flow path. Discharge amount variable discharge means for supplying the resin flowed through the sub resin flow path to the additional molding means is disposed, and the discharge amount of the discharge amount variable discharge means is controlled by the operation control means.
A melt polymerization / compression molding system characterized by this.   Pressure detection means for detecting the resin pressure in the main resin flow path is disposed at the pressure detection part downstream from the branch part, and the operation control means is responsive to the resin pressure detected by the pressure detection means. The melt polymerization / compression molding system according to claim 1, wherein the discharge amount of the discharge amount variable discharge means is controlled to maintain a constant pressure detected by the pressure detection means. The melt polymerization / compression molding system according to claim 2 , wherein an on-off valve means is disposed downstream of the pressure detection portion in the main resin flow path.
  A plurality of compression molding means are provided, and a downstream portion of the main resin flow path is branched into a plurality of branch resin flow paths corresponding to each of the plurality of compression molding means. The melt polymerization / compression molding system according to claim 3, wherein the on-off valve means and the second discharge means are disposed in each of the flow paths.   The melt polymerization / compression molding system according to claim 1, wherein the operation control means controls the discharge amount of the variable discharge amount discharge means in accordance with the operating state of the second discharge means.   On-off valve means is disposed between the branch portion in the main resin flow path and the second discharge means, and the operation control means can change the discharge amount according to the operating state of the on-off valve means. The melt polymerization / compression molding system according to claim 1, wherein the discharge amount of the discharge means is controlled.   A plurality of compression molding means are provided, and a downstream portion of the main resin flow path is branched into a plurality of branch resin flow paths corresponding to each of the plurality of compression molding means. The melt polymerization / compression molding system according to claim 6, wherein the on-off valve means and the second discharge means are disposed in each of the flow paths.   The melt polymerization / compression molding system according to any one of claims 1 to 7, wherein the resin to be melt polymerized in the melt polymerization means is a polyester resin.   The melt polymerization / compression molding system according to any one of claims 1 to 8, wherein the compression molding means performs compression molding of a pre-molded body to be put into a container by adding blow molding later.

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