JP5741074B2 - Sheet extrusion machine and sheet extrusion manufacturing method - Google Patents

Description

  The present invention relates to a sheet extrusion molding machine and a sheet extrusion manufacturing method.

  Conventionally, a sheet manufactured using polyester, polyethylene, polypropylene, polyamide, polycarbonate, polyolefin, acrylic resin or the like is generally manufactured by a process as shown in FIG.

  FIG. 7 is a schematic view showing an example of a sheet extrusion molding machine.

  In FIG. 7, the sheet extruder 30 is provided with an extruder 1, a gear pump 2, a filter 3, a base 4, a cooling roll 5, a stretching device 6, and a winder 7 in order from the upstream side in the polymer flow direction. A thickness meter 8 is installed between the stretching device 6 and the winder 7, and a thickness controller 9 is electrically connected to the thickness meter 8 and the base 4.

  In the above apparatus, the raw material polymer is supplied to the extruder 1, melted, and then extruded to the gear pump 2. The gear pump 2 has a function of keeping the discharge amount (delivery amount) constant, and the polymer discharged from the constant amount is removed of foreign matters and the like through the filter 3 and then supplied to the base 4. The base 4 is provided with a slit having a predetermined gap. The polymer is extruded from the slit into a sheet shape, cooled and solidified on a rotating cooling roll 5, and then a solidified sheet 10 is obtained. The solidified sheet 10 is continuously stretched by the stretching device 6 and wound up as a sheet by the winder 7. At that time, the thickness in the width direction of the sheet (direction orthogonal to the paper surface) is measured by the thickness meter 8, and the slit gap of the base 4 is adjusted by the thickness controller 9 based on the obtained thickness data, and a certain range A product sheet having an inner thickness (small variation in thickness) is obtained.

  In general, the sheet extrusion molding machine has characteristics of the polymer to be used, such as polyethylene, unstretched sheet having a thickness of 50μ, polypropylene, biaxially stretched sheet having a thickness of 15μ, etc. Designed accordingly. However, as the seat manufacturing business continues for many years, there are frequent opportunities such as new product development and business change, and there are cases where new capital equipment is newly invested and new dedicated machines are installed. It is very common practice to divert existing equipment to new polymer and thickness varieties for shortening.

  According to the knowledge of the present inventors, it is sufficient that this existing equipment can be used for new varieties with the current specifications, but in many cases, it is often the case that the machine needs to be modified because the specification range does not match. there were. Among them, in particular, the extruder may not meet the range of the polymer discharge amount, and the screw may be redesigned and remanufactured as necessary.

  However, remodeling of the screw takes several months, and the cost is heavy. If the amount of discharge is large compared to the new product in the change requirements, the number of revolutions, that is, the amount of discharge is reduced without modification. There were often cases of diversion alone. At first glance, it seems that this operation can be applied without any problem, but in reality, the rotation of the screw becomes unstable, and fluctuations in discharge occur, resulting in uneven thickness in the sheet discharge direction and width direction. . In addition, there is a problem that even if an attempt is made to adjust the thickness, the current thickness cannot be determined due to discharge fluctuation, and the adjustment cannot be performed. Furthermore, with fluctuations in the rotation of the screw, the melting of the polymer becomes unstable, and the unmelted material may flow out, and particle-containing or multi-component polymers may cause poor kneadability, resulting in unstable film formation. It was a problem.

  In general, a single-screw extruder has a proportional relationship between the polymer discharge amount and the screw rotation speed, and there has been a problem in that increasing the screw rotation for a stable operation inevitably increases the polymer discharge amount. Prior art document 1 describes a structure for discharging a polymer at the bottom of a filter housing. Originally, the present invention aims to discharge the polymer in the long-term staying part in the housing and reduce the mixing of the polymer staying deterioration product into the product sheet. However, by adopting the same structure, it is necessary for the stability of the extruder. The polymer flow rate can be divided into the amount required for sheet production and the amount discharged. However, discharging the polymer at the bottom of the filter housing makes the polymer flow distribution in the housing unstable, leading to a reduction in filter filtration life, and pressure fluctuations in the filter. In some cases, the staying deterioration product may lead to the outflow to the sheet side. Further, in the paragraph [0017] of Patent Document 1, the polymer purge rate (discharge rate) is preferably 0.1 to 10%, more preferably 0.2 to 5%, but depending on the choice of the extruder. In some cases, 50% or more must be discharged. In this case, if the filter has a discharge port, it is often not stable as described above.

JP 2010-284832 A

  The object of the present invention is to secure a polymer flow rate necessary for the stability of the extruder when the discharge of the sheet production conditions is out of the specification range of the extruder, and to make the polymer flow rate necessary for the sheet production and the discharge amount. It is an object of the present invention to provide a sheet extrusion molding machine and a sheet extrusion manufacturing method capable of separately and stably operating an extruder and manufacturing a sheet.

  In order to achieve the above-mentioned object, the present invention connects an extruder that heats, melts and discharges a thermoplastic polymer, a die that widens the molten polymer into a sheet, and connects the extruder and the die. In a sheet extrusion molding machine having a polymer transport pipe for transporting a polymer, the flow path for guiding the molten polymer transported from the extruder in the direction of the die is connected to the polymer transport pipe. Provided is a sheet extrusion molding machine characterized in that it has two paths with a flow path leading in a direction of discharging to the outside.

  Also, an extruder that heats, melts and discharges the thermoplastic polymer, a die that widens the molten polymer into a sheet, a polymer transport pipe that connects the extruder and the die and transports the molten polymer The polymer transport pipe includes a flow divider for diverting the molten polymer flowing through the pipe wall and the molten polymer flowing through the pipe center, and the melting flowing through the pipe wall diverted by the diverter A sheet extrusion molding machine having a flow path for discharging the polymer out of the system is also a preferred form.

  Further, at least two or more extruders for heating, melting and discharging the thermoplastic polymer are provided, a feed block for joining the polymers flowing from the two extruders, a die for widening the molten polymer into a sheet, and the extrusion A sheet extruder comprising a machine, a feed block, and a die, and a polymer transport pipe for transporting the molten polymer, wherein the molten polymer transported from the extruder is transferred to the polymer transport pipe. A flow path leading in the direction of the die and a branch path of the flow path leading in the direction of discharging the molten polymer out of the system, and a flow path for returning the molten polymer discharged from the branch path back to at least one extruder A sheet extruder is also provided.

Further, in the sheet extrusion molding machine configured with the polymer flow path according to any one of the foregoing, the discharge port of the extruder is provided with a throttle pipe for narrowing a flow path pipe diameter or a valve capable of adjusting pressure. A sheet extrusion machine is also preferable,
Furthermore, the sheet extrusion manufacturing method characterized by manufacturing a sheet | seat using the sheet | seat extrusion molding machine in any one of the above-mentioned is also provided.

  In the present invention, “outside the system” means outside the sheet extrusion molding machine connected from the extruder to the die, and “outside” means discharging the polymer from a place other than the die.

  According to the present invention, as shown below, by separating the polymer from the extruder into the amount necessary for sheet production and the discharge amount, even when the discharge of the sheet production conditions is outside the specification range of the extruder alone, it is stable. Then, the extruder can be operated to produce a sheet.

It is a schematic block diagram of the sheet | seat extrusion molding machine provided with the flow path which discharges | emits a polymer out of the system which shows one Embodiment of this invention. It is a schematic block diagram of the sheet | seat extrusion machine provided with the discharge flow path in the flow divider and the flow divider which shows one Embodiment of this invention. It is a schematic block diagram of the sheet | seat extrusion molding machine provided with the flow path which returns the discharged | emitted polymer again to an extruder which shows one Embodiment of this invention. It is a schematic block diagram of the sheet | seat extrusion molding machine provided with the flow path which returns the discharged | emitted polymer again to an extruder which shows one Embodiment of this invention. It is a schematic block diagram of the sheet | seat extrusion molding machine provided with the discharge flow path and the throttle tube which shows one Embodiment of this invention. It is a schematic block diagram of the sheet | seat extrusion molding machine provided with the discharge flow path and the pressure control valve which shows one Embodiment of this invention. It is a schematic block diagram of a general sheet extrusion molding machine. It is a schematic block diagram which shows the internal flow path of a general feed block.

  Hereinafter, examples of the best mode of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of the present invention and is a schematic view of a sheet extrusion molding machine provided with a flow path for discharging a polymer out of the system. Here, 11a is an extruder and 15 is a die, and a polymer transport pipe is connected between them. In the polymer transport pipe, 12a is a branch path that divides the polymer flow in two directions, and a flow path 13 for guiding the polymer in the direction of the die and a discharge flow path 14 are provided outside the system. The cooling roll 5, the stretching device 6, the winder 7 and the like after the base 15 are the same as the configuration of FIG.

  When the extruder 11a is operated with the configuration of FIG. 1, the polymer discharged from the extruder 11a is divided into the direction of the die 15 and outside the system. By doing so, even when it is desired to manufacture a sheet with a discharge amount lower than the discharge range of the extruder 11a, the apparent discharge can be increased, so that the extruder 11a can be stably operated, which is a preferable mode. .

  The amount of polymer to be separated is determined by the pressure loss balance between the flow path 13 that leads in the direction of the die and the flow path 14 that discharges to the outside of the system. Therefore, the diameter and length of the polymer transport pipe should be determined according to the required separation amount. However, the length and the like are generally limited by the size of the building where the equipment is installed, and the pressure loss in the direction of the base increases thereby. It is preferable to adjust the pressure. At that time, the diameter and length of the polymer transport pipe may be changed, or although not shown, a valve for adjusting the pressure may be provided in the vicinity of the outlet of the flow path 14 for discharging the polymer out of the system.

  The branch path 12a is preferably smooth without branching at an acute angle so that no staying portion is generated inside. Further, the position of the branch path 12a may be any position between the extruder 11a and the die 15. However, the branch path 12a is preferably installed in a place where it does not interfere with the cooling roll 5 or the extruder 11a and is easy to work. Although a filter is not illustrated between the extruder 11a and the base 15 in FIG. 1, the positional relationship can be set in any way even when a filter is installed.

  FIG. 2 shows an embodiment of the present invention, and is a schematic view of a sheet extrusion machine provided with a flow path for discharging the polymer on the tube wall out of the system by a flow divider. Here, 11a is an extruder and 15 is a die, and a polymer transport pipe is connected between them. In the polymer transport pipe 16, a flow divider for diverting the polymer flowing through the pipe wall and the polymer flowing through the pipe center in the cross-sectional direction of the pipe. A flow path 14 for discharging outside the system is provided. The cooling roll 5, the stretching device 6, the winder 7 and the like after the base 15 are the same as the configuration of FIG.

  As in the case of FIG. 1, the configuration of FIG. 2 can increase the apparent discharge even when it is desired to manufacture a sheet with a discharge amount lower than the discharge range of the extruder 11 a, so that the extruder 11 a can be stably operated. This is a preferred form.

  Further, in the case of FIG. 2, the polymer flowing through the pipe wall is discharged, but generally the pipe wall has a slow polymer flow rate and a long residence time in the system. Depending on the diameter and length of the tube, it may deteriorate due to oxidation and heat, and this deteriorated polymer can be discharged out of the system, improving the quality of the surface defects of the sheet, etc. Thus, a more preferable form is obtained.

  Further, conventionally, the polymer on the pipe wall diverted by the flow divider 16 flows to a position corresponding to the end in the width direction of the base 15 so that the deteriorated polymer on the pipe wall does not enter the product portion. Although it was configured, when the amount to be separated is large, the width that can be adopted as a product may be narrow because the width of the deteriorated polymer mixed portion at the end of the sheet is wide, but with the configuration of FIG. The relatively deteriorated polymer can be discharged out of the system, and a relatively clean polymer can be allowed to flow through the die, which is a more preferable form than when a conventional shunt is used alone.

  In the configuration of FIG. 2 as well, the amount of polymer to be separated is determined by the pressure loss balance between the flow path 13 leading in the direction of the die and the flow path 14 discharged to the outside of the system. It is good to decide the diameter and length, but generally the length is often limited by the size of the building where the equipment is installed, etc., so that the pressure loss in the direction of the base increases, It is preferable to adjust the pressure on the flow path 14 side to be discharged out of the system. At that time, the diameter and length of the polymer transport pipe may be changed, or although not shown, a valve for adjusting the pressure may be provided in the vicinity of the outlet of the flow path 14 for discharging the polymer out of the system.

  It is preferable that no stagnant portion is generated inside the flow divider 16. Further, the position of the flow divider 16 may be any position between the extruder 11a and the die 15, but it is installed in a place where it does not interfere with the cooling roll 5 or the extruder 11a and is easy to work. It is preferable to install it immediately before 15. Since the ratio of the deteriorated polymer in the vicinity of the polymer transport pipe wall mixed into the sheet can be reduced by installing it immediately before the base 15, this is a preferable mode.

  1 and 2, the polymer is discharged out of the system of the sheet extrusion molding machine. The discharged polymer may be disposed of, or may be recovered and charged again. When collecting, it collects in block lump shape, and after crushing, it may be used in the form of flakes, or may be used in pellet form with a granulator or the like. Further, a die that discharges the polymer in a strand shape, a cooling facility, and a cutting facility may be installed at the outlet of the discharge flow path 14, and directly pelletized, and the raw material may be charged again. Although the operation method can be determined based on cost and labor, it is a good mode to input the raw material again rather than discard it because it becomes an effective means when the polymer price is high.

  3 and 4 show an embodiment of the present invention and are schematic views of a sheet extrusion molding machine provided with a flow path for returning the polymer discharged out of the system to the extruder again. Here, 11a is a first extruder and 11b is a second extruder, which are connected to a base 15 via a feed block 18. FIG. 8 shows the structure of the internal flow path of a general feed block 18. In FIG. 8, the polymer flowing from the first extruder 11 a flows to the middle layer flow path 22, the polymer flowing from the second extruder 11 b flows to the surface layer flow path 23, and the two flows merge at the merge portion 24. As a result, the polymer is laminated in the thickness direction in the feed block 18 and is extruded as a sheet in which the polymer is laminated in the thickness direction from the slit 26 through the manifold 25 inside the base. The cooling roll 5, the stretching device 6, the winder 7 and the like after the base 15 are the same as the configuration of FIG.

  A polymer transport pipe is connected between the extruders 11a and 11b and the feed block 18. In the polymer transport pipe, 12a is a branch path that divides the polymer flow in two directions. A discharge passage 14 is provided outside. The polymer passing through 14 is pushed out by the gear pump 17, flows through the flow path 21 for returning the polymer to the system again, and returns to the first extruder 11a.

  The configuration of FIG. 4 is an example in which the second extruder 11b branches in the same manner, flows through the combined flow path 12b, and returns to the first extruder 11a again.

  3 and 4 makes it possible to reuse the polymer once discharged out of the system in a molten state, and even when it is desired to manufacture a sheet with a discharge amount lower than the discharge range of the extruder, it is apparent Since the discharge can be increased, the extruder can be operated stably, which is a preferable mode.

  The amount of polymer to be separated is determined by the ability of the gear pump 17 provided at the end of the flow path 13 leading to the cap direction and the flow path 14 discharging to the outside of the system. It is good to decide the length and the capacity of the gear pump. The gear pump 17 is preferably provided with a pressure increasing capability to return the polymer to the extruder 11a again.

  When returning to the extruder, the position where the polymer is reintroduced is preferably the part where the polymer is melted, that is, the measuring part in the vicinity of the tip, more preferably the plasticizing part before the measuring part. Since the measurement is not disturbed by returning to this position, a good form is obtained.

  3 and 4 exemplify returning to the first extruder 11a, it may be returned to both of 11b. When the quality of the sheet is high, such as surface defects, some of the polymer in the form of FIGS. 3 and 4 circulates constantly, so the deterioration of the polymer may progress, but the side that circulates at that time By allowing the polymer to flow in the middle layer of the laminated sheet, the surface defects of the sheet and deterioration of characteristics can be reduced. For sheets where sheet surface properties such as slipperiness and roughness are important, the same type of polymer is laminated, often with collected material flowing in the middle layer and new material flowing in the surface layer, to reduce raw material costs. It becomes an effective means. In such a case, the same effect can be obtained by flowing the polymer to be discharged and circulated through the middle layer, which is a preferable mode.

  It is also possible to periodically stop the operation and clean the circulatory polymer. Although it depends on the type of polymer used, it is preferable to wash once a week, more preferably once every three days.

  In order to reduce the frequency of cleaning, it is preferable to reduce the oxygen concentration at the raw material inlet of the extruder in order to slow down the deterioration rate of the polymer, and it is also a good mode to blow nitrogen gas or the like.

  FIGS. 5 and 6 show an embodiment of the present invention, and are schematic views of a sheet extrusion molding machine provided with pressure adjusting means at the tip of the extruder for further stabilizing the extruder. Here, 11a is an extruder and 15 is a die, and a polymer transport pipe is connected between them. In the polymer transport pipe, 12a is a branch path that divides the polymer flow in two directions, and a flow path 13 for guiding the polymer in the direction of the die and a discharge flow path 14 are provided outside the system. In the case of FIG. 5, a throttle tube 19 is installed between the extruder 11a and the branch path 12a, and in the case of FIG. 6, a pressure adjusting valve 20 is installed. The cooling roll 5, the stretching device 6, the winder 7 and the like after the base 15 are the same as the configuration of FIG.

  5 and 6, when the extruder 11a is operated, the polymer discharged from the extruder 11a is divided into the direction of the die 15 and outside the system. By doing so, even when it is desired to manufacture a sheet with a discharge amount lower than the discharge range of the extruder 11a, the apparent discharge can be increased, so that the extruder 11a can be stably operated, which is a preferable mode. . Furthermore, the pressure at the tip of the extruder may fluctuate depending on the discharge amount, separation amount, position of the branch path 12a, and the like, which may affect the discharge fluctuation. The pressure can be increased, and the extruder can be operated stably, which is a preferred form.

  The amount of polymer to be separated is determined by the pressure loss balance between the flow path 13 that leads in the direction of the die and the flow path 14 that discharges to the outside of the system. Therefore, the diameter and length of the polymer transport pipe should be determined according to the required separation amount. However, the length and the like are generally limited by the size of the building where the equipment is installed, and the pressure loss in the direction of the base increases thereby. It is preferable to adjust the pressure. At that time, the diameter and length of the polymer transport pipe may be changed, or although not shown, a valve for adjusting the pressure may be provided in the vicinity of the outlet of the flow path 14 for discharging the polymer out of the system.

  If the operating conditions are determined within a narrow range, it is preferable for operation because the throttle tube 19 has a small number of staying portions and the like. However, it is easy to apply the pressure adjusting valve 20 to various conditions in order to cope with a wide variety of products. This is a preferred form.

  In any of the configurations described so far, the ratio of separating the polymer depends on the extruder to be used, the specifications of the sheet to be manufactured, and the production amount, but it is preferably 50% or more when large and about 15% when small. More preferably, the separation amount is about 30% in terms of operation.

  In the above preferred embodiment, the case where the discharge of the current extruder is low for new varieties has been shown as an example, but it may be a good form to separate the polymer out of the system even when the discharge is large. For example, if the polymer discharge rate required for sheet production is 200 kg / hr and the maximum discharge range of the extruder is 150 kg / hr, the polymer for 50 kg / hr will be insufficient, but the screw rotation of the extruder If you try to increase the number beyond the capacity range, it may be possible depending on the durability of the extruder. However, since high shear is generally applied to the polymer by high discharge, the temperature state may change due to the molecular state of the polymer or shear heat generation. In order to discharge the portion where the temperature is too high, it is preferable that a part or the polymer of the tube wall is allowed to flow out of the system.

  The polymer applicable to the present invention is not particularly limited, for example, polypropylene, polyester, polyethylene, polyamide, polycarbonate, polyolefin, polylactic acid, acrylic polymer, and may be a thermoplastic resin or a thermosetting resin.

  The configuration of the polymer film may be a single layer configuration or may have a laminate configuration of two or more layers. Moreover, when employ | adopting a extending | stretching process, you may carry out using the sequential biaxial stretching machine which combined longitudinal stretching and horizontal stretching one by one, and it carries out using the simultaneous biaxial stretching machine which performs vertical stretching and horizontal stretching simultaneously. May be. Of course, an unstretched film that does not undergo a stretching step may be used.

  The polymer sheet obtained by the above-described production method is suitable for various industries and applications such as packaging applications such as packages and laminates, magnetic recording medium applications such as digital video cameras, optical applications such as displays, and semiconductor applications such as flexible substrates. Can be used.

[Example 1]
A sheet extrusion machine having the configuration shown in FIG. 1 was used, and sheets such as a cooling roll, a drawing device, and a winder after the die were manufactured in the configuration shown in FIG. Polyethylene terephthalate was used as the polymer, and the extrusion temperature was 280 ° C. The discharge amount necessary for manufacturing the sheet was 500 kg / hr, but the discharge range of the extruder was a specification range of 700 kg / hr to 2500 kg / hr, so the total pressure loss in the direction from the branch path 12a to the base 15 was 3. The pipe diameter and length are determined so that the total pressure loss from the branch path 12a to the discharge flow path direction is 1.4 MPa, and the operation of the extruder is performed so that a discharge amount of 700 kg / hr is produced. 200 kg / hr was discharged.

  A T die having a width of 1800 mm and a slit gap of 2.8 mm was used as a die, a cooling roll having a diameter of 1000 mm was used, and sheets were produced at a speed of 20 m / min for one week. As a result, a stable operating state was obtained because the extruder was within the range of use, and a film of good quality was obtained without thickness unevenness due to discharge fluctuations and outflow of unmelted material.

The polymer discharged out of the system was collected in the form of block blocks, then crushed and pelletized with a granulator, and applied to another production opportunity at a later date.
[Example 2]
A sheet extrusion machine having the configuration shown in FIG. 2 was used, and the steps such as the cooling roll after the die, the stretching device, and the winder were manufactured with the configuration shown in FIG. The polymer was low density polyethylene and the extrusion temperature was 220 ° C. The discharge amount necessary for the production of the sheet was 100 kg / hr, but the discharge range of the extruder was a specification range of 150 kg / hr to 500 kg / hr, so the total pressure loss in the direction from the flow divider 16 to the base 15 was 6. The pipe diameter and length are determined so that the total pressure loss from the flow divider 16 toward the discharge flow path becomes 3.3 MPa, and the extruder is operated so that a discharge amount of 150 kg / hr is produced. 50 kg / hr was discharged. The shunt was designed to shunt a range of 3 mm on the surface layer with respect to a pipe diameter of 25 mm.

  The die was manufactured using a T die having a width of 900 mm and a slit gap of 1.5 mm, a cooling roll having a diameter of 600 mm, and a sheet was manufactured at a speed of 12 m / min for 5 days. As a result, a stable operating state was obtained because the extruder was within the range of use, and a film of good quality was obtained without thickness unevenness due to discharge fluctuations and outflow of unmelted material.

The polymer discharged out of the system was recovered as a block-like lump and discarded.
[Example 3]
Using a sheet extrusion molding machine having the configuration shown in FIG. 3, sheets such as a cooling roll, a stretching device, and a winder after the die were manufactured in the configuration shown in FIG. 7. Polypropylene was used as the polymer, and the extrusion temperature was 230 ° C. The discharge amount necessary for manufacturing the sheet was 260 kg / hr, but the discharge range of the extruder was a specification range of 300 kg / hr to 800 kg / hr. Therefore, the discharge amount of the extruder was set to 300 kg / hr. The amount returned from 12a to the extruder 11a via the gear pump 17 was 40 kg / hr. Nitrogen gas was allowed to flow at the raw material inlet of the extruder 11a so that the polymer from the gear pump 17 returned to the plasticizing section of the extruder. The feed block 18 has a three-layer structure in which the polymer from 11a is arranged in the middle layer and the polymer from 11b is arranged in the front and back layers, the die is set to a width of 1200 mm, and the slit gap is set to 1.8 mm, and the diameter is 1000 mm. Using a cooling roll, the sheet was produced for 3 days at a speed of 15 m / min. As a result, a stable operating state was obtained because the extruder was within the range of use, and a film of good quality was obtained without thickness unevenness due to discharge fluctuations and outflow of unmelted material.
[Example 4]
A sheet extrusion machine having the configuration shown in FIG. 6 was used, and the steps such as the cooling roll, the stretching device, and the winder after the die were manufactured with the configuration shown in FIG. Polypropylene was used as the polymer, and the extrusion temperature was 230 ° C. The discharge amount necessary for manufacturing the sheet was 260 kg / hr, but the discharge range of the extruder was a specification range of 300 kg / hr to 800 kg / hr, so the total pressure loss in the direction of the base 15 from the branch path 12a was 10. The pipe diameter and length are determined so that the total pressure loss from the branch path 12a to the discharge flow path becomes 1.6 MPa, and the operation of the extruder is performed so that a discharge amount of 300 kg / hr is produced. 40 kg / hr was discharged. Nitrogen gas was allowed to flow at the raw material inlet of the extruder 11a. The die was manufactured using a T-die set to a width of 1000 mm and a slit gap of 1.8 mm, a cooling roll having a diameter of 1000 mm, and a sheet was manufactured at a speed of 15 m / min for 3 days. As a result, a stable operating state was obtained because the extruder was within the range of use, and a film of good quality was obtained without thickness unevenness due to discharge fluctuations and outflow of unmelted material.
[Comparative Example 1]
A sheet extrusion molding machine having a configuration in which the branch path 12a and the discharge direction flow path 14 shown in FIG. 1 are not provided was used, and the sheet after the die was manufactured in the configuration shown in FIG. As a result of extrusion under the same conditions as described in Example 1, the discharge range lower limit of 700 kg / hr of the extruder must be operated at 500 kg / hr, and the discharge fluctuation in units of 1 to 2 seconds to several minutes Occurred, the thickness unevenness was large, and the sheet could not be manufactured stably. In addition, an abnormal noise was generated such that the screw slipped, and an unmelted product was observed on the sheet.

  The present invention can be applied to a sheet extruder apparatus using a thermoplastic molten polymer, but the application range is not limited thereto.

DESCRIPTION OF SYMBOLS 1 Extruder 2 Gear pump 3 Filter 4 Cap 5 Cooling roll 6 Stretching device 7 Winder 8 Thickness meter 9 Thickness controller 10 Solidified sheet 11a First extruder 11b Second extruder 12a Branching path 12b Combined flow path 13 Flow path 14 Flow path to be discharged out of the system 15 Base 16 Divider 17 Gear pump 18 Feed block 19 Throttle tube 20 Pressure adjusting valve 21 Flow path for returning the polymer back into the system 22 Middle flow path of the feed block 23 Surface flow of the feed block Path 24 Feed block confluence 25 Cap manifold 26 Cap slit 30 Sheet extruder

Claims (3)

At least two or more extruders that heat, melt and discharge thermoplastic polymer, a feed block that joins the polymers flowing from the two extruders, a die that widens the molten polymer into a sheet, and the extruder, In a sheet extrusion molding machine comprising a polymer transport pipe for connecting the feed block and the base and transporting the molten polymer, the molten polymer transported from the extruder is transferred to the polymer transport pipe of the base. A flow path that leads in a direction and a branch path that leads to a direction that discharges the molten polymer out of the system, and a flow path that returns the molten polymer discharged from the branch path to at least one extruder. A sheet extrusion molding machine. 2. A sheet extrusion molding machine comprising a polymer flow channel according to claim 1 , wherein the discharge port of the extruder is provided with a throttle tube for narrowing the flow channel diameter or a valve capable of adjusting pressure. Extrusion machine. Using a sheet extrusion molding machine according to claim 1 or 2, sheet extrusion manufacturing method characterized by the production of sheets.

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