WO2015002035A1

WO2015002035A1 - Twin-screw extrusion device and method for manufacturing film

Info

Publication number: WO2015002035A1
Application number: PCT/JP2014/066747
Authority: WO
Inventors: 山田　晃; 圭原田
Original assignee: 富士フイルム株式会社
Priority date: 2013-07-02
Filing date: 2014-06-24
Publication date: 2015-01-08
Also published as: KR20160015278A; CN105339156B; CN105339156A; KR101810856B1; JP6049648B2; JP2015027785A

Abstract

Provided is a twin-screw extrusion device comprising: a cylinder that has an extrusion port which extrudes molten resin; two screws that have an outer diameter (φ) of 100mm or more, and are disposed inside the cylinder in a manner so as to be capable of rotating; a cooling system that is installed on the cylinder wall, and has a first coolant supply/discharge port and a coolant channel through which a coolant, which exchanges heat with the molten resin inside the cylinder, flows; a temperature detection means that detects the temperature of the molten resin extruded from the extrusion port, and is positioned at the downstream side of the extrusion port of the cylinder in the direction of flow of the molten resin, and at the upstream side of a film production device which moulds the molten resin; and a resin temperature control means which adjusts the amount of the coolant supplied to the first coolant supply/discharge port, and controls the temperature difference between a resin set temperature and the molten resin temperature that has been detected by the temperature detection means, said temperature difference being controlled so as to be equal to or less than a predetermined threshold value.

Description

Twin screw extrusion apparatus and film manufacturing method

The present invention relates to a twin-screw extruder and a film manufacturing method.

Polyester is applied to various applications such as electrical insulation and optical applications. Among these, solar cell applications such as a sheet for protecting the back surface of a solar cell (so-called back sheet) have attracted attention as electrical insulation applications in recent years.

Films and sheets using polyester usually have a large amount of carboxyl groups and hydroxyl groups on the surface, tend to cause hydrolysis reaction under environmental conditions where moisture exists, and tend to deteriorate over time. For example, the installation environment in which solar cell modules are generally used is an environment that is constantly exposed to wind and rain, such as outdoors, and because it is exposed to conditions where hydrolysis reaction is likely to proceed, the hydrolyzability of polyester is stable. It is desired that the state is controlled to be suppressed.

In order to improve the hydrolysis resistance of the polyester resin, it is preferable to reduce the amount of terminal carboxyl groups (Acid value (AV)). In order to reduce the amount of terminal carboxyl groups, it is effective to lower the temperature of the extruded resin during melt extrusion with an extruder. However, when the unmelted component increases due to the low resin temperature, the unmelted component promotes crystallization, causing crystallization turbidity and deterioration of adhesion of the product.

In relation to the above situation, it is effective to cool the inside of the extruder after melting (for example, see JP 2012-91494 A). In this case, a cooling zone is provided downstream of the extruder in the resin extrusion direction. Since cooling requires high cooling efficiency, a water cooling system using water having high latent heat of evaporation is effective.

As a technology related to the cooling of the extruder, the cooling capacity is judged based on the temperature state of the barrel and the water flow state in order to reduce the burden of adjusting the opening of the variable throttle valve by the operator when the operating conditions of the extruder are changed A temperature control device that selects a necessary solenoid valve and adjusts the flow rate of water according to the cooling load is disclosed (for example, see Japanese Patent Application Laid-Open No. Hei 2-238920).
Also disclosed is a resin temperature control method that prevents hunting of the resin temperature immediately before the mold by controlling the cylinder temperature setting value based on the change over time of the resin temperature in the cylinder and the molding resin temperature immediately before the mold. (For example, see JP-A-11-34149).

In addition, while the changed target set temperature value is set from the difference value between the material temperature measured value and the target temperature set value of the material temperature stored in advance, the temperature adjustment mechanism is based on the changed target set temperature value and the medium temperature measured value. There has been disclosed a temperature control device that controls heating or cooling of a medium in a circulation circuit based on the result of PID calculation performed (see, for example, Japanese Patent Application Laid-Open No. 2002-307539).
In addition to the above, there is a disclosure relating to a technique for controlling cooling in an extrusion apparatus (see, for example, JP-A-63-278819 and JP-A-2009-83313).

As described above, in the cooling zone provided downstream of the extruder in the resin extrusion direction, when cooling with water as a refrigerant, water has a high latent heat of vaporization, which is advantageous in terms of cooling efficiency. If continuously supplied, overcooling tends to occur. Therefore, a method of cooling while controlling the temperature by intermittent water injection is common.

For example, resin films (such as polyester films) used under harsh outdoor conditions such as solar cell applications are required to have excellent weather resistance, and it is possible to extrude films with excellent weather resistance. It is effective to perform melt extrusion at as low a temperature as possible. However, as a harmful effect of melting at a low temperature, it is conceivable that the quality other than the weather resistance is impaired, such as acceleration of film turbidity (crystallization) and deterioration of film forming suitability. Therefore, there has been a demand for low-temperature extrusion technology that does not impair film properties and film-forming suitability.

On the other hand, in an extruder (particularly a large-sized extruder), a cooling pipe is generally arranged along the periphery of a cylinder wall in which a screw is accommodated, and cooling water is supplied from one end (supply port) of this pipe. . The supplied cooling water evaporates immediately in the vicinity of the supply port, so heat exchange is remarkably insufficient from the vicinity of the center of the entire length of the piping to the downstream side, and a uniform cooling effect is obtained for the entire cylinder. There may not be. If the amount of water injection is increased in consideration of the heat exchange on the downstream side, it becomes difficult to evaporate and the cooling effect cannot be obtained. As a result, temperature unevenness occurs in the cylinder peripheral direction. Moreover, since temperature control is generally performed based on the cylinder temperature, fluctuations in the water amount cycle occur due to cylinder temperature variations, and the temperature of the molten resin is not stabilized.

Such non-uniform cooling effects lead to quality fluctuations (weather resistance, white turbidity, etc.) of film molded products. Usually, quality standards and process conditions that allow for safety factors are determined for these fluctuations. It is adjusted as it occurs. Therefore, when such a safety factor is taken into consideration, it is difficult to maximize the original capacity of the facility.
Therefore, from the viewpoint of improving and homogenizing product quality, improvement of non-uniform cooling of the cylinder, in other words, establishment of a technology for stabilizing the temperature of the resin to be melt-extruded has been demanded.

The present invention has been made in view of the above. The present invention provides a twin-screw extrusion apparatus and a film manufacturing method that can stably maintain the temperature of a resin to be melt-extruded as compared with a conventional twin-screw extruder and produce a resin having low haze and excellent weather resistance.

Specific means for achieving the above-described problems are as follows.
<1> Cylinder having an extrusion port for extruding molten resin, two screws having an outer diameter of φ100 mm or more arranged rotatably in the cylinder, first refrigerant supply / discharge port, and heat exchange with the molten resin in the cylinder And a cooling system disposed on the cylinder wall (preferably along the circumference of the cylinder in the cylinder wall), and on the downstream side of the cylinder outlet in the molten resin flow direction. And a temperature detection means for detecting the temperature of the molten resin extruded from the extrusion port, and disposed on the upstream side of the film forming apparatus for film formation of the molten resin, and to the first refrigerant supply / discharge port of the refrigerant Resin temperature control means for controlling the temperature difference between the temperature of the molten resin detected by the temperature detection means and the resin set temperature to be equal to or less than a predetermined threshold (predetermined threshold) by adjusting the supply amount; Prepared An axial extrusion apparatus.
<2> In the molten resin distribution direction, the resin has a resin distribution pipe through which the molten resin circulates on the downstream side of the extrusion port of the cylinder and on the upstream side of the film forming apparatus for film formation of the molten resin. Is a twin screw extruder according to <1>, which has at least a temperature measuring part disposed inside the pipe that is 10 mm or more away from the inner wall surface of the resin flow pipe, and a damage preventing material that prevents the temperature measuring part from being damaged. It is.
<3> The refrigerant is the twin-screw extruder according to <1> or <2>, which is a working fluid that exchanges heat with the molten resin by latent heat of vaporization.

<4> The resin temperature control means adjusts the supply amount of the refrigerant to the first refrigerant supply / discharge port in the range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg. <1> to <3> It is a twin-screw extrusion apparatus as described in any one.
<5> The twin-screw extruder according to any one of <1> to <4>, wherein the refrigerant is water.
<6> The resin temperature control means supplies the refrigerant to the first refrigerant supply / exhaust port with a supply time (seconds / time) of 10 seconds / time or more and 120 seconds / time or less, and 0 of the above cycle. Any one of <1> to <5>, in which the temperature difference between the resin temperature and the resin set temperature is controlled to be equal to or less than a predetermined threshold value (predetermined threshold value) It is a twin-screw extrusion apparatus as described in one.
<7> The resin temperature control means is a method in which the haze value of the resin film formed by the film forming apparatus exceeds a predetermined upper limit threshold value Q1 or the haze value of the resin film formed by the film forming apparatus varies. When the rate exceeds a predetermined threshold value Q3, the resin set temperature is increased, and when the haze value of the resin film formed by the film forming apparatus is less than the predetermined lower limit threshold value Q2, the resin set temperature is set. The twin-screw extruder according to any one of <1> to <6>.
<8> The resin temperature control means, when the temperature difference between the resin temperature and the resin set temperature does not reach a predetermined threshold value or less within a predetermined time, by changing the rotation speed of the screw, The twin-screw extruder according to any one of <1> to <7>, wherein the resin temperature is controlled to a resin set temperature.

<9> The cooling system further includes a second refrigerant supply / exhaust port for discharging the refrigerant from the refrigerant flow path, and a flow switching valve for switching the flow direction of the refrigerant, and the resin temperature control means switches the flow switching valve. Thus, the first cooling for supplying the refrigerant to the first refrigerant supply / exhaust port and discharging the refrigerant from the second refrigerant supply / exhaust port, and supplying the refrigerant to the second refrigerant supply / exhaust port for supplying the first refrigerant The twin-screw extrusion apparatus according to any one of <1> to <8>, wherein the second cooling discharged from the discharge port is switched at a predetermined cycle.

<10> A step of melting a thermoplastic resin while controlling a temperature of the resin melted in a cylinder having two screws having an outer diameter of φ100 mm or more arranged rotatably, and a melted thermoplastic resin A step of extruding into a film form from a molding die, and a step of solidifying the extruded thermoplastic resin on a cooling roll,
In the melting process, the temperature of the molten resin extruded from the cylinder extrusion port is detected before the process of extruding into a film shape, and the temperature difference between the detected temperature of the molten resin and the resin set temperature is detected on the cylinder wall. In this film manufacturing method, the amount of refrigerant supplied to the arranged cooling system is adjusted to be controlled to be equal to or lower than a predetermined threshold value.
<11> The refrigerant according to <10>, wherein the refrigerant is a working fluid that exchanges heat with the molten resin by latent heat of vaporization.
<12> The melting step is the film production method according to <10> or <11>, wherein the supply amount of the refrigerant is adjusted in a range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg.
<13> The method for producing a film according to any one of <10> to <12>, wherein the refrigerant is water.
<14> In the melting step, the supply of the refrigerant to the cooling system is intermittently performed at a cycle of 10 seconds / time to 120 seconds / cycle with a supply time (seconds / cycle) of more than 0% and 40% or less of the cycle. By performing, the film manufacturing method according to any one of <10> to <13>, wherein the temperature difference between the temperature of the molten resin and the resin set temperature is controlled to a predetermined threshold value or less.
<15> In the melting step, the haze value of the resin film formed by the film forming apparatus exceeds a predetermined upper limit threshold value Q1, or the variation rate of the haze value of the resin film formed by the film forming apparatus. Is higher than the predetermined threshold value Q3, the resin set temperature is raised,
The film according to any one of <10> to <14>, wherein the resin set temperature is lowered when the haze value of the resin film formed by the film forming apparatus is less than a predetermined lower threshold Q2. It is a manufacturing method.
<16> The melting step is performed by changing the number of rotations of the screw when the temperature difference between the temperature of the molten resin and the resin set temperature does not reach a predetermined threshold value within a predetermined time. The method for producing a film according to any one of <10> to <15>, wherein the temperature of the molten resin is controlled to a resin set temperature.
<17> The cooling system includes a first refrigerant supply / exhaust port, a refrigerant flow channel through which the refrigerant flows, a second refrigerant supply / discharge port through which the refrigerant is discharged from the refrigerant flow channel, and a flow switching valve that switches a flow direction of the refrigerant. Have
In the melting step, by switching the flow switching valve, the first cooling that supplies the refrigerant to the first refrigerant supply / discharge port and discharges it from the second refrigerant supply / discharge port, and the refrigerant is supplied to the second refrigerant supply / discharge port. The film manufacturing method according to any one of <10> to <16>, wherein the second cooling that is supplied to the outlet and discharged from the first refrigerant supply / exhaust opening is switched at a predetermined cycle.

According to the present invention, there is provided a twin-screw extrusion apparatus and a film manufacturing method that can stably maintain the temperature of the resin to be melt-extruded as compared with the conventional twin-screw extruder and produce a resin having low haze and excellent weather resistance. Is done.

FIG. 1 is a schematic diagram illustrating a configuration example of a film manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a configuration example of a twin-screw extruder constituting the film manufacturing apparatus of FIG. FIG. 3 is a schematic perspective view showing the cooling flow path disposed along the cylinder periphery of the twin-screw extruder. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a schematic cross-sectional view showing a cross section orthogonal to the resin flow direction of the resin temperature detector 50. FIG. 6 is a flowchart showing an intermittent water injection control routine according to the first embodiment of the present invention. FIG. 7 is a flowchart showing an intermittent water injection control routine according to the second embodiment of the present invention. FIG. 8 is a flowchart showing an intermittent water injection control routine according to the third embodiment of the present invention. FIG. 9 is a flowchart showing a flow switching control routine according to the fourth embodiment of the present invention. FIG. 10 is a schematic piping configuration diagram showing a refrigerant flow path that switches the flow direction of the refrigerant and supplies the cylinder to the cylinder in the fourth embodiment of the present invention. FIG. 11 is a schematic diagram for explaining a method for measuring the cylinder temperature. FIG. 12 is a schematic diagram for explaining a method of measuring the terminal COOH amount of the resin film.

Hereinafter, embodiments of the twin-screw extrusion apparatus of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the embodiments shown below.

(First embodiment)
A first embodiment of a twin-screw extruder according to the present invention will be described with reference to FIGS. In the present embodiment, a resin temperature detector for measuring the temperature of the resin is disposed at an intermediate position between the gear pump and the filter, and the refrigerant is intermittently generated at a predetermined pulse cycle based on the measured resin temperature. Will be described in detail by taking as an example a twin-screw extruder that supplies a predetermined time for cooling control of the molten resin.

As shown in FIG. 1, the film manufacturing apparatus 200 of the present embodiment is discharged from a biaxial extruder 100 </ b> A, a gear pump 44 provided downstream of the molten resin extruded from the biaxial extruder, and a gear pump. A filter 42 for filtering the molten resin and a forming die 40 that is a film forming machine for forming the molten resin are provided.
The biaxial extruder 100A is a biaxial extruder 100 having two screws, and a resin temperature detector that is disposed between the gear pump and the filter and is an example of temperature detecting means for detecting the temperature of the molten resin. 50 and a control device 60 which is an example of a resin temperature control means.

[Twin screw extruder]
As shown in FIGS. 2 to 4, the twin-screw extruder 100 is a cylinder (barrel) having a raw material supply port 12 for supplying a raw material resin and an extrusion port (hereinafter also referred to as an extruder outlet) 14 for extruding a molten resin. 10 and two

screws

20A and 20B each having an outer diameter of φ100 mm or more and rotating in the cylinder 10, a temperature regulator 30 arranged around the cylinder 10 and controlling the temperature in the cylinder 10, and a cylinder And a cooling pipe 35 for cooling the air.

Extruders used for producing polyester films using the melt extrusion method are generally roughly classified into single-screw and multi-screw depending on the number of screws. As a multi-screw extruder, a twin-screw extruder (two-screw extruder) Screw extruders are widely used.

The cylinder 10 has a raw material supply port 12 for supplying the raw material resin, and an extruder outlet 14 through which the heat-melted resin is extruded.
As will be described later, the cylinder 10 is formed by a cylinder wall having a temperature control function of a molten resin. In this embodiment, the cylinder 10 is formed by providing a temperature controller 30 and also serving as the cylinder wall. Yes.
A raw material supply device 46 for supplying raw material resin is connected to the raw material supply port 12.

The inner wall surface of the cylinder 10 is preferably made of a material that is excellent in heat resistance, wear resistance, and corrosion resistance, and can ensure friction resistance with the resin. Generally, nitrided steel whose inner surface is nitrided is used, but chromium molybdenum steel, nickel chromium molybdenum steel, and stainless steel can also be nitrided and used. For applications that require wear resistance and corrosion resistance in particular, a bimetallic cylinder in which a corrosion-resistant and wear-resistant material alloy such as nickel, cobalt, chromium or tungsten is lined on the inner wall surface of the cylinder 10 by centrifugal casting. It is effective to use or form a ceramic sprayed coating.

The cylinder 10 is provided with

vents

16A and 16B (indicated by arrows in FIG. 2) for drawing a vacuum. By evacuating through the

vents

16A and 16B, volatile components such as moisture in the resin in the cylinder 10 can be efficiently removed. By appropriately arranging the

vents

16A and 16B, raw materials (pellets, powders, flakes, etc.) in an undried state, crushed waste (fluffs) of the film produced during film formation, etc. can be used as raw material resins as they are. .
In the present embodiment, two

vents

16A and 16B are provided. However, regarding the arrangement of the vents, it is required that the opening area and the number of the vents are appropriate from the relationship with the deaeration efficiency. The twin screw extruder 100 desirably has one or more vents. In addition, since there exists a possibility that molten resin may overflow from a vent and a residence deterioration foreign material may increase when there are too many vents, it is preferable that a vent is one place or two places.
In addition, the resin staying on the wall surface near the vent and the deposited volatile components may fall into the extruder 100 (cylinder 10), and if dropped, it may be manifested as foreign matter in the product. It is important not to do so. For retention, optimization of the shape of the vent lid and appropriate selection of the upper and side vents are effective, and precipitation of volatile components is generally performed by a method of preventing the precipitation by heating the piping or the like.

For example, when polyethylene terephthalate (PET) is melt-extruded, the suppression of hydrolysis, thermal decomposition, and oxidative decomposition greatly affects the quality of the product (film). For example, oxidative decomposition can be suppressed by evacuating the raw material supply port 12 or performing a nitrogen purge.
Further, by providing the vents at a plurality of locations, even when the raw material water content is about 2000 ppm, the same extrusion as when a resin dried to 50 ppm or less is extruded on a single axis is possible.
In order to suppress resin decomposition due to shearing heat generation, it is preferable not to provide segments such as kneading as much as possible within a range in which extrusion and deaeration can be compatible.

The atmosphere of the raw material supply port 12 is preferably suppressed to an oxygen concentration of less than 10% by volume. Since the oxygen concentration (O ₂ concentration) in the atmosphere of the raw material supply port for supplying the polyester resin and the terminal sealing material is suppressed to less than 10% by volume, the polyester resin is prevented from being deteriorated and sealed with the terminal sealing material. Since the stopping effect appears well, it is excellent in the effect of improving hydrolysis resistance. The oxygen concentration is preferably 7% by volume or less, more preferably 5% by volume or less, for the same reason as described above.
The oxygen concentration can be adjusted by a method of introducing an inert gas (for example, nitrogen gas) into a supply unit having a raw material supply port, a method of evacuating, or the like.

Further, since the shear heat generation increases as the pressure at the screw outlet (extruder outlet) 14 increases, the pressure at the extruder outlet 14 is within a range in which the degassing efficiency and the stability of extrusion by the

vents

16A and 16B can be secured. It is preferable to make it as low as possible.

The

screws

20A and 20B have a screw diameter (outer diameter) D of 100 mm or more in the cylinder 10 and are rotatably provided by driving means 21 including a motor and gears. A large twin-screw extruder having a screw diameter D of 100 mm or more can be mass-produced. On the other hand, resin melting unevenness, that is, resin temperature unevenness tends to occur in the circumferential direction of the cylinder. Easy to accompany. However, in the present invention, even when a large twin screw extruder having a screw diameter D of 100 mm or more is used, the temperature variation of the molten resin is suppressed, and the resin crystals that are likely to occur when melted at a low temperature The white turbidity (decrease in haze) of the resin due to crystallization can be more effectively suppressed.
Thereby, the physical property variation of the resin film finally produced is suppressed.

The screw diameter D is preferably 150 mm or more, more preferably 160 mm to 240 mm from the viewpoint that mass production is possible and the effects of the present invention are more effective.

The twin screw extruder is roughly divided into a meshing type and a non-meshing type of two screws, and the meshing type has a larger kneading effect than the non-meshing type. In the present invention, any of a meshing type and a non-meshing type may be used, but from the viewpoint of suppressing kneading by sufficiently kneading the raw material resin, it is preferable to use a meshing type.
The rotational directions of the two screws are also divided into the same direction and different directions. The different direction rotation type screw has a higher kneading effect than the same direction rotation type screw. The co-rotating type has a self-cleaning effect and is effective in preventing retention in the extruder.
Furthermore, the axial direction is also parallel and oblique, and there is also a conical type shape used when applying strong shear.

In the twin screw extruder that can be used in the present invention, screw segments of various shapes are used. As the shape of the

screws

20A and 20B, for example, a full flight screw provided with a single spiral flight 22 of equal pitch is preferably used.

Further, it is preferable that at least one resin kneading member is disposed downstream of the raw material supply port 12 in the resin extrusion direction in the longitudinal direction of the cylinder 10. The resin kneading member is a kneading segment that imparts shear such as a kneading disk or a rotor. In this embodiment, kneading

disks

24A and 24B are installed as shown in FIG. By providing the kneading segment, the raw material resin can be more reliably melted and kneaded. The kneading segment is disposed in a heating zone assigned in the longitudinal direction of the cylinder (heating zones Z1 to Z7 shown in FIG. 2 in this embodiment), and a kneading section for promoting melting and kneading of the raw material resin is provided in the heating zone. Is formed.

In addition, by using a reverse screw or a seal ring in this heating zone, it is possible to form a melt seal when damming the resin and pulling the vent. For example, a reverse screw may be provided in the vicinity of the

vents

16A and 16B in FIG.

It is effective to provide a cooling zone (temperature control section) for cooling and controlling the temperature of the molten resin downstream of the center of the longitudinal direction of the cylinder 10 constituting the biaxial extruder 100 in the resin extrusion direction. is there. When the heat transfer efficiency of the cylinder 10 is higher than the shear heat generation, as shown in FIG. 2, by providing a screw 28 with a short pitch in the cooling zone Z9, the resin moving speed of the cylinder 10 wall surface is increased and the temperature control efficiency is increased. Can do. From the viewpoint of enhancing the cooling effect, the pitch of the screws 28 located in the cooling zone (temperature control section) is preferably 0.5D to 0.8D (D: screw diameter [mm]).

As shown in FIG. 2, the temperature controller 30 existing around the cylinder 10 has nine regions (heating zones Z1 to Z7 and cooling zones) in which the cylinder 10 extends in the longitudinal direction from the raw material supply port 12 to the extruder outlet 14. Z8 to Z9). Specifically, heaters C1 to C7 are disposed in seven regions from the upstream side in the resin extrusion direction, and coolers C8 to C9 are disposed in two regions from the downstream side in the resin extrusion direction. The adjuster 30 is configured. In this way, the periphery of the cylinder 10 is divided into heating zones Z1 to Z7 and cooling zones Z8 to Z9 by the heaters C1 to C7 and the coolers C8 to C9 that are arranged separately, and the cylinder 10 is divided into regions. The temperature can be controlled to a desired temperature (for each zone). In the cooling zone, it is also possible to provide a heater and adjust the temperature by using the heater together.
FIG. 2 shows an example of a structure in which the cylinder is divided into 9 zones in the longitudinal direction (melting resin flow direction) and the temperature can be controlled for each zone. However, the number of regions (zones) is limited to 9 zones. Instead, the number of regions (zones) can be arbitrarily selected according to the purpose or the like.

For heating, a band heater or a sheathed wire aluminum cast heater is generally used. However, a heater is not limited to these, For example, the heat-medium circulation heating method is also applicable.
On the other hand, cooling is performed by providing a cooling pipe for circulating the refrigerant inside the cylinder 10 and circulating the refrigerant through the cooling pipe. Moreover, while providing cooling piping in a cylinder, you may be comprised in the aspect which provides other structures, such as winding cooling piping around a cylinder, and performs cooling.

Further, as shown in FIGS. 1 and 4, a temperature detection sensor S2 for detecting the temperature of the cylinder is attached to the cylinder wall. The temperature detection sensor S2 can detect the cylinder temperature during melt-kneading continuously or at a predetermined timing. Thereby, control by the temperature controller 30 is performed. The detected value is sent to the control device 60 at all times or as necessary. A known thermocouple or the like can be used for the temperature detection sensor S2.

While the raw material resin is heated and melted in the cylinder as described above, the temperature controller 30 causes the inner wall of the cylinder 10 on the extruder outlet 14 side to be a cooling zone (temperature control) of the melting point Tm (° C.) or less of the polyester resin (raw material resin). Part)). If the wall surface temperature near the extruder outlet 14 of the cylinder 10 is controlled to be equal to or lower than the melting point Tm (° C.) of the raw material resin in the cooling zone, it is possible to prevent the resin from being heated excessively and increasing the amount of terminal COOH. From the viewpoint of reliably suppressing the increase in the amount of terminal COOH, the temperature in the cooling zone is preferably within the range of (Tm-100) ° C to Tm ° C, and within the range of (Tm-50) ° C to (Tm-10) ° C. Is more preferable.

The length of the cooling zone (in this embodiment, the cooling zones Z8 to Z9), that is, the length from the tip of the extrusion port in the screw axis direction is preferably 4D to 11D (D: screw diameter). If the length of the cooling zone is 4D or more, the molten and heated resin is effectively cooled to suppress an increase in terminal COOH. On the other hand, if the length of the cooling zone is 11D or less, the resin can be prevented from being excessively cooled and solidified, and melt extrusion can be performed smoothly.
It is preferable that the resin temperature _{T out} in the extruder outlet 14 to the Tm + 30 ° C. or less. However, because some of the molten resin resin temperature _{T out} is too low in the extruder outlet 14 is also likely to be solidified, the resin temperature _{T out} in the extruder outlet 14 is more able to Tm ~ (Tm + 25) ℃ or less Preferably, (Tm + 10) ° C. to (Tm + 20) ° C. is more preferable.

[Cooling piping]
As shown in FIGS. 3 and 4, the cooling pipe 35 has a cylinder wall (that is, a heating zone that forms a part of the cylinder and is provided with a heater (in this embodiment, the heating zones Z1 to Z1 in FIG. 2). Z7) is a cooling system configured by providing a refrigerant flow path 37 through which the refrigerant flows, and at one end of the refrigerant flow path 37 is a first refrigerant supply / exhaust port for supplying the refrigerant. The other end has a refrigerant supply / exhaust port 37a, and the other end has a refrigerant supply / exhaust port 37b that discharges the refrigerant that has passed through the refrigerant flow path 37 and finished heat exchange. By cooling, the temperature of the molten resin can be stably controlled in a desired temperature range.

The refrigerant supply / exhaust port 37a may be connected to an external refrigerant supply device in order to supply the refrigerant to the refrigerant flow path. Further, the refrigerant supply / exhaust port 37b may be connected to a tank or the like that stores the discharged refrigerant. Further, the refrigerant supply / exhaust port 37a and the refrigerant supply / exhaust port 37b may be connected to each other via a pipe, so that the cooling circulation system may be configured so that the refrigerant can be used without being discarded.

In this embodiment, although not shown, the refrigerant supply / exhaust port 37a and the refrigerant supply / exhaust port 37b are connected by a pipe (not shown) to which a circulation pump, a supply stop valve, and a cooling device for cooling the refrigerant are attached. The refrigerant discharged from the refrigerant supply / exhaust port 37b can be circulated and supplied to the refrigerant supply / exhaust port 37a after being adjusted to a predetermined temperature by a cooling device.

As the refrigerant, a liquid medium such as water, alcohol, ether or a mixture thereof, or oil is generally used, but a working fluid (liquid medium) having latent heat of vaporization is preferable in terms of high cooling efficiency. Such a working fluid can efficiently exchange heat with the molten resin by latent heat of vaporization. Among these, water is preferable as the working fluid because it has a high latent heat of vaporization and is dangerous in handling and heat transfer efficiency. In the present embodiment, water is used as a refrigerant.

When supplying the refrigerant from the refrigerant supply / exhaust port 37a to the refrigerant flow path 37, the amount of the refrigerant supplied to the refrigerant supply / exhaust port 37a in one supply operation is 0.001L (liter; the same applies hereinafter) / resin 1kg to It is preferably adjusted to a range of 0.150 L / kg of resin. When the supply amount of the refrigerant is 0.001 L / kg of resin or more, heat exchange on the downstream side of the refrigerant flow path becomes better, and the temperature unevenness of the molten resin between the upstream side and the downstream side of the refrigerant flow path Easy to keep small. Further, if the supply amount of the refrigerant is 0.150 L / kg of resin or less, it is prevented that the supply amount of the refrigerant is too large to evaporate, and the cooling efficiency is maintained and the temperature unevenness of the molten resin is kept small. It's easy to do.
The supply amount of the refrigerant is preferably 0.002 L / resin 1 kg to 0.100 L / resin 1 kg, more preferably 0.003 L / resin 1 kg or more, from the viewpoint of further maintaining the uniformity of the temperature of the molten resin in the cylinder. 0.050 L / kg of resin.

Cooling can be performed after being extruded from an extruder, but it is laminar, has low heat exchange efficiency, generates local cooling, and involves quality variation and local solidification. There is. Therefore, the cooling is preferably performed on the downstream side of the extruder that can utilize high-efficiency heat exchange by convective heat transfer.

[Resin temperature detector]
The resin temperature detector 50 is disposed between a filter 42 and a gear pump 44, which will be described later, and a temperature constituted by a resin temperature detection sensor S1 and a support plate 54 in which a temperature measuring unit is disposed in the resin flow pipe. It is a detection means. This temperature detection means can directly detect the temperature of the extruded molten resin. In the resin temperature detector 50, as shown in FIGS. 1 and 5, the resin temperature detection sensor S1 is attached to the wall material of the resin flow pipe 52 having an inner diameter of 80 mm through which the molten resin flows, and the temperature of the molten resin is directly measured. It can be detected. The resin temperature detection sensor S1 is a position where the temperature measuring unit comes into contact with the resin passing through the center of the cross section orthogonal to the resin flow direction of the resin flow tube 52 (in this embodiment, the temperature measurement unit is the inner wall surface of the resin flow tube 52). To 40 mm, that is, at the center of the pipe). Therefore, from the viewpoint of preventing the sensor from being damaged due to the resistance of the flowing molten resin, the support plate 54 is attached as a damage preventing material having a strength capable of withstanding the resistance of the molten resin.
In the present embodiment, the support plate 54 is disposed upstream of the resin temperature detection sensor S1 in the resin flow direction in order to reduce the load applied to the resin temperature detection sensor S1 by receiving the resin pressure of the flowing resin.

When the temperature is measured when the resin is heated and melted by the cylinder, usually the temperature of the cylinder itself is detected and adjusted, but it is affected by temperature unevenness in the cylinder. Therefore, the resin temperature detection sensor S1 in the present embodiment directly detects the resin temperature, not the cylinder temperature. As a result, more accurate temperature control of the molten resin becomes possible, and temperature fluctuation of the molten resin in the cylinder can be effectively suppressed.

In addition, since the temperature of the molten resin flowing through the resin distribution pipe is likely to fluctuate due to the influence of the installation environment of the device, the temperature measuring unit that measures the temperature of the molten resin is installed from the inner wall surface of the resin distribution pipe. It is preferable to be disposed at a position separated by 10 mm or more in the inner direction (diameter direction). The temperature of the resin can be measured more accurately because the temperature measuring unit is separated from the inner wall surface by 10 mm or more. As for the installation position of a temperature measuring part, it is more preferable that it is 20 mm or more away from the inner wall face of the resin distribution pipe in the pipe internal direction.

As shown in FIG. 5, the support plate 54 is provided by fixing one end and the other end of the plate material to the inner wall surface in the diameter direction of the tube cross section. May be fixed to the inner wall surface. For example, from the viewpoint of easy circulation of the molten resin, only one end of the plate material may be fixed to the inner wall surface as shown in FIG. 5, and the other end may be fixed at the same position as the temperature measuring unit without being fixed. Moreover, the form which fixed the sensor inside the support plate may be sufficient.

As a material for the breakage prevention material, a material that does not corrode upon contact with the molten resin, and a material that is excellent in heat conduction is preferable. Examples of the material include a stainless alloy material (SUS material) and chrome molybdenum steel.
The size and thickness of the breakage prevention material are not particularly limited, and may be selected according to the inner diameter of the resin flow tube, the flow rate of the molten resin, the properties of the molten resin, and the like. The damage prevention material may be a plate material, a column material, a bar material, or the like.

The damage prevention material such as the support plate 54 may be disposed upstream of the resin temperature detection sensor in the resin distribution direction so as not to receive the resistance of the flowing molten resin itself. Further, the breakage prevention material is not limited to the upstream side of the resin temperature detection sensor, and conversely, may be disposed on the downstream side of the resin temperature detection sensor at a position close to the sensor (for example, a position adjacent to the sensor). The presence of the support plate may be a reinforcing plate when the resistance of the molten resin is received, so that deformation and breakage of the sensor may be prevented.
Further, a resin temperature detection sensor may be embedded in the breakage prevention material, and the sensor may be configured not to be directly loaded with molten resin.

The resin temperature detector 50 can detect the temperature of the molten resin continuously or at a predetermined timing. The detected value is sent to the control device 60 at all times or as necessary. A known thermocouple or the like can be used for the temperature detection sensor S1.

[Gear pump]
A gear pump 44 that adjusts the flow rate with a driving gear and a driven gear is provided on the upstream side of the resin temperature detector 50 downstream of the extruder outlet 14 of the twin screw extruder 100 in the molten resin extrusion direction. Both gears may be driven. By providing the gear pump 44 between the extruder 100 and the molding die 40, which is a polyester film forming machine, fluctuations in the extrusion amount are reduced, and a certain amount of resin is supplied to the molding die 40. Will improve. In particular, when a twin screw extruder is used, an aspect in which extrusion stabilization by the gear pump 44 is achieved is preferable because the pressurization capability of the extruder itself is low.

By using the gear pump 44, it is possible to reduce the pressure fluctuation (output pressure fluctuation) on the discharge side of the gear pump 44 to 1/5 or less of the pressure fluctuation (input pressure fluctuation) on the suction side, and the resin pressure fluctuation width is ± It can be reduced within 1%. As other merits, it is possible to perform filtration with a filter without increasing the pressure at the tip of the screw. Therefore, it is possible to prevent the resin temperature from increasing, improve the transportation efficiency, and shorten the residence time in the extruder. It is also possible to prevent the amount of resin supplied from the screw from fluctuating over time due to an increase in the filtration pressure of the filter. However, when the gear pump 44 is installed, depending on the method of selecting the equipment, the equipment becomes larger and the residence time of the resin becomes longer, and the shearing stress of the gear pump part may cause the molecular chain of the resin to be broken. It is important that the performance of the polyester, such as hydrolysis resistance, is not impaired.

In the gear pump 44, if the difference (differential pressure) between the discharge side pressure (input pressure) and the suction side pressure (output pressure) becomes too large, the load on the gear pump 44 increases and shear heat generation increases. Therefore, the differential pressure during operation is preferably 20 MPa or less, preferably 15 MPa, and more preferably 10 MPa or less. From the viewpoint of uniform film thickness, it is effective to control the screw rotation of the extruder or to use a pressure control valve in order to keep the primary pressure of the gear pump 44 constant.

[Molding die and filter]
Downstream of the resin temperature detector 50 in the direction of extrusion of the molten resin, as a film-forming machine for forming a film such as a polyester film, the molten resin extruded from the extruder outlet 14 is formed into a film (for example, as a band-shaped film). A discharging die 40 and a cooling roll (not shown) (for example, a casting drum) for cooling and solidifying the discharged film are provided. The molten resin extruded from the extruder outlet 14 of the cylinder 10 is made into a sheet form from the forming die 40 and sent to a cooling roll, solidified by cooling, and formed into a sheet. In this way, an unstretched polyester sheet is obtained.

In addition, a filter 42 is provided between the extruder outlet 14 of the cylinder 10 and the molding die 40 to prevent unmelted resin and foreign matters from being mixed into the polyester resin used for film formation. A metal fiber filter or the like can be used as the filter.
The filter pore diameter can be appropriately selected within the range of 1 μm to 100 μm.

It is preferable to adjust the humidity to 5% RH to 60% RH after the melt (molten resin) is extruded from the molding die 40 until it contacts the cooling roll (air gap), for example, 15% RH to 50%. It is more preferable to adjust to% RH. By adjusting the humidity in the air gap to the above range, it is possible to adjust the COOH amount and OH amount on the film surface. Moreover, the amount of carboxylic acid on the film surface can be reduced by adjusting to low humidity.

Also, by increasing the resin temperature once and then cooling, it is possible to suppress the increase in the amount of terminal COOH and to suppress the occurrence of unmelted foreign matter. Furthermore, the effect which suppresses the haze rise of the polyester resin formed into a sheet form is acquired. In particular, when a film is formed on a thick sheet, the haze is likely to increase due to insufficient cooling rate, but the increase in that case can be suppressed.

[Control device]
The control device 60 is a resin temperature control means mainly responsible for the control of the twin-screw extruder 100A. The twin-screw extruder 100, temperature detection sensors S1 to S2, and a circulation pump and a supply stop valve constituting a cooling circulation system, It is electrically connected to a cooling device or the like, and is configured so that the resin temperature can be appropriately controlled by controlling the supply of refrigerant to the twin-screw extruder according to the detection values from the temperature detection sensors S1 and S2. ing.

Next, in the control routine by the control device 60 which is a resin temperature control means for controlling the biaxial extrusion device 100A of the present embodiment, the refrigerant is supplied to the refrigerant supply / exhaust port 37a (first refrigerant supply / exhaust port) of the cooling pipe. The intermittent water injection control routine for intermittently supplying certain water will be described with reference to FIG.

When the power of the control device 60 is turned on by turning on the start switch of the film manufacturing apparatus of the present embodiment, the control system of the biaxial extrusion device 100A is started, and the intermittent water injection control routine is executed. The system may be started manually instead of automatically.

When this routine is executed, first, in step 100, the temperature of the molten resin is detected by the temperature detection sensor S1 in order to determine whether or not the resin temperature needs to be controlled. Next, in step 120, the detected resin temperature exceeds the preset set temperature t of the molten resin, and the temperature difference Δt obtained by subtracting the set temperature t from the detected resin temperature is the threshold temperature T. Whether it is less than or not is determined.

If it is determined in step 120 that the temperature difference Δt is equal to or higher than the threshold temperature T, the resin temperature is too high, and the amount of terminal carboxyl groups increases, which may reduce the hydrolysis resistance of the resin to be formed. Then, the process proceeds to step 140, and the output of the water amount (refrigerant) is determined by PID control according to the deviation of the detected value of the resin temperature with respect to the set temperature. When it is determined in step 120 that the temperature difference Δt is less than the threshold temperature T, the process proceeds to step 220 because the resin temperature is not excessively increased and the amount of terminal carboxyl groups is unlikely to increase significantly.

In the next step 160, supply of the refrigerant to the refrigerant supply / exhaust port 37a is started. At this time, the supply of water as the refrigerant is preferably performed while adjusting the supply amount in the range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg. By setting the supply amount within this range, good cooling efficiency can be obtained, and temperature unevenness of the molten resin can be effectively reduced.
In the present embodiment, the supply of the refrigerant is started by opening a supply stop valve provided in the cooling circulation system and driving the circulation pump.

At this time, it is preferable that the refrigerant is intermittently supplied at the following cycle. That is, the supply of the refrigerant to the first refrigerant supply / exhaust port is adjusted in a cycle of 10 seconds to 120 seconds and the supply time (seconds / time) is adjusted to a range of more than 0% and 40% or less of the above cycle. It is preferably performed. When the supply time (second / time) is more than 0% of the above-described cycle (10 seconds to 120 seconds), the temperature difference between the resin temperature and the resin set temperature can be kept small. Further, when the supply time (second / time) is 40% or less of the above-described cycle (10 seconds to 120 seconds), the temperature difference between the resin temperature and the resin set temperature can be kept small.
Especially, it is preferable that supply time (second / time) is adjusted to the range of 0.3% or more and 30% or less of the above-mentioned period.
The point that the refrigerant is intermittently supplied in the above-described cycle is the same in the second to fourth embodiments described later.

From the viewpoint of suppressing the temperature unevenness of the molten resin, the temperature difference between the resin temperature and the resin set temperature is preferably 1 ° C. or less, and more preferably 0.5 ° C. or less. When the temperature difference is 1 ° C. or less, the temperature unevenness of the molten resin can be reduced.
The temperature difference between the resin temperature and the resin set temperature is the same in the second to fourth embodiments described later.

Subsequently, in step 180, the supply time is calculated from the cycle of supplying the refrigerant, the output required for cooling, and the control constant, and it is determined whether or not the supply time of the refrigerant has passed. When it is determined in step 180 that the refrigerant supply time has elapsed, the supply of the refrigerant commensurate with the output required for cooling is completed, and in the next step 200, the supply of the refrigerant to the refrigerant supply / discharge port 37a is stopped. . In this embodiment, the supply stop valve provided in the cooling circulation system is closed, and the supply of the refrigerant is stopped. At this time, the flow path of the refrigerant is switched to a bypass that does not pass through a cylinder (not shown), so that the circulating pump is maintained in a driving state.
When it is determined in step 180 that the supply time of the refrigerant has not yet elapsed, the supply of the refrigerant is continued as it is until a predetermined supply time has elapsed.

Thereafter, in step 220, it is determined whether or not there is a request for stopping the operation of the twin-screw extruder, and when it is determined that a request for stopping the operation is not made, the temperature of the melted and kneaded molten resin is continuously maintained stably. Since it is necessary, the process proceeds to step 240. On the other hand, if it is determined in step 220 that the operation stop request has been made, it is not necessary to continuously control the resin temperature, and thus this routine is terminated.

In Step 240, it is determined whether or not the time from the start of supply in Step 160 to the start of the next supply, that is, the refrigerant supply cycle has reached a predetermined cycle S. If it is determined in step 240 that the predetermined period S has been reached, the refrigerant is intermittently supplied in the predetermined period, so that the process returns to step 100 and the same control as described above is continued. The Here, when it is determined that the predetermined cycle S has not been reached, since intermittent supply in a predetermined cycle cannot be performed, the system waits until the predetermined cycle S, and when the cycle S is reached. Returning to step 100 again, the same control as above is continued.

In general, the temperature of the molten resin in the cylinder can be controlled by a cooling zone of the temperature controller 30 provided in the extruder. However, particularly in a large extruder having an outer diameter of 100 mm or more, the cylinder is intended to be cooled with water. Then, temperature unevenness in the circumferential direction of the cylinder and fluctuations in the water amount cycle are likely to occur. Further, even if the detection value of the temperature detection sensor S2 for temperature control attached to the cylinder 10 can be controlled to be constant, the cooling efficiency of the cylinder has changed due to factors such as generation of scale and water temperature change. There is a problem that the temperature inevitably changes. Such fluctuations in the resin temperature lead to fluctuations in the quality of the final molded film products (white turbidity (decrease in haze) and deterioration in weather resistance). Standards and process conditions are determined, and adjustments are made while causing loss each time. Therefore, considering the safety factor, it is difficult to maximize the original capacity of the facility.
In view of the above, there has been a demand for a technology for stabilizing cylinder cooling for improving and homogenizing product quality. In view of such circumstances, in the present invention,
As described above, it is extruded from the extrusion port by the temperature detection sensor S1, which is a temperature detection means disposed on the downstream side of the extrusion port of the cylinder in the molten resin flow direction and on the upstream side of the film forming apparatus for molding the molten resin. When the temperature of the molten resin is detected and Δt exceeds a predetermined threshold value based on the temperature difference (Δt) between the detected resin temperature and the resin set temperature, the refrigerant supply amount (preferably Is controlled within the range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg), and is supplied to the refrigerant supply / exhaust port 37a (that is, supplied to the cooling system), thereby controlling Δt below a predetermined threshold value. To do.
Thereby, compared with the conventional twin-screw extruder, the temperature of the resin to be melt-extruded can be stably maintained, and a resin having low haze and excellent weather resistance can be obtained.

In the present invention, as shown in the present embodiment, the thermoplastic resin is melted while controlling the temperature of the resin melted in a cylinder having two screws having an outer diameter of φ100 mm or more arranged rotatably. And a step of extruding the molten thermoplastic resin from the forming die into a film shape, and a step of solidifying the extruded thermoplastic resin on a cooling roll. The temperature of the molten resin extruded from the outlet is detected before the step of extruding into a film, and the temperature difference between the detected temperature of the molten resin and the set temperature of the resin is detected in a cooling system disposed on the cylinder wall. By adjusting the supply amount of the supplied refrigerant (preferably in the range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg), the film is controlled to be equal to or less than a predetermined threshold value. Manufacturing. By this method (film manufacturing method according to the present invention), the temperature of the resin to be melt-extruded can be stably maintained as compared with a conventional twin-screw extruder, and a resin having low haze and excellent weather resistance can be obtained.

As described above, in the step of melting the thermoplastic resin, the temperature controller 30 heats and cools the cylinder 10 while controlling the temperature, and the

screws

20A and 20B are rotated so that the raw material resin is supplied from the raw material supply port 12. Supply. The raw material resin supplied into the cylinder is heated by the temperature controller 30, friction between the resins accompanying rotation of the

screws

20A and 20B, friction between the resin and the

screws

20A and 20B and the cylinder 10, and the like. And is gradually moved toward the extruder outlet 14 as the screw rotates. At this time, melting and kneading of the raw material resin are promoted by the kneading

disks

24A and 24B disposed in the cylinder. That is, of the heating zones Z1 to Z7, heating is started in the zone Z1, and the heating zones Z4 and Z6 in which the

kneading disks

24A and 24B are disposed are heating zones Z2 to Z3 and Z5 as kneading sections for resin kneading. , Z7 mainly function as a transport unit for melting and transporting the resin.
At this time, the temperature of the molten resin itself is stably controlled while controlling the amount and timing of water injection to the cooling pipe as described above in accordance with the temperature detected by the temperature detection sensors S1 and S2. As a result, the temperature of the resin itself can be stabilized, a low haze can be maintained even when melted at a low temperature, and a resin having excellent weather resistance is stably provided.

The raw material resin supplied into the cylinder is heated to a temperature equal to or higher than the melting point Tm (° C.). However, if the resin temperature is too low, melting during melt extrusion may be insufficient and ejection from the molding die 40 may be difficult. There is. On the other hand, if the resin temperature is too high, the terminal COOH is remarkably increased by thermal decomposition, which may lead to a decrease in hydrolysis resistance. From these viewpoints, the heating temperature by the temperature controller 30 and the rotation speed of the

screws

20A and 20B are adjusted, and the cooling control by the cooling pipe is adjusted.
At this time, the maximum resin temperature (T _max ; [° C.]) in the longitudinal direction (resin extrusion direction) in the twin screw extruder is preferably (Tm + 40) ° C. to (Tm + 60) ° C., and (Tm + 40) ° C. to ( Tm + 55) ° C. is more preferable, and (Tm + 45) ° C. to (Tm + 50) ° C. is further preferable.

In the production of the film, a thermoplastic resin is used as a raw material resin and is melted in a cylinder. Examples of the thermoplastic resin include polyester, polyolefin, polyamide, polyurethane and the like. In the present invention, polyester is preferred in that the effect of obtaining a resin having low haze and excellent weather resistance is more effectively exhibited.
Polyester includes polyethylene terephthalate (PET) and polyethylene-2,6-naphthalate (PEN), preferably PET.

The raw material resin is not particularly limited as long as it is a raw material of the film and contains a resin, and may contain a slurry of inorganic particles or organic particles in addition to a resin such as polyester.
As polyester, what was synthesize | combined using the dicarboxylic acid component and the diol component may be sufficient, and commercially available polyester may be sufficient.

When the polyester is synthesized, for example, it can be obtained by subjecting (A) a dicarboxylic acid component and (B) a diol component to an esterification reaction and / or a transesterification reaction by a known method.
(A) Examples of the dicarboxylic acid component include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid Aliphatic dicarboxylic acids such as ethylmalonic acid, adamantane dicarboxylic acid, norbornene dicarboxylic acid, isosorbide, cyclohexanedicarboxylic acid, decalin dicarboxylic acid, and the like, terephthalic acid, isophthalic acid, phthalic acid, 1,4- Naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 4,4′-diphenyl dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 5-sodium sulfo Isophthalic acid, phenyli Boy carboxylic acid, anthracene dicarboxylic acid, phenanthrene carboxylic acid, 9,9'-bis (4-carboxyphenyl) a dicarboxylic acid or its ester derivatives such as aromatic dicarboxylic acids such as fluorene acid.
(B) Examples of the diol component include fats such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, and 1,3-butanediol. Diols, cycloaliphatic dimethanol, spiroglycol, isosorbide and other alicyclic diols, bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 9,9'-bis (4-hydroxyphenyl) ) Diol compounds such as aromatic diols such as fluorene.

(A) As a dicarboxylic acid component, the case where at least 1 sort of aromatic dicarboxylic acid is used is preferable. More preferably, the dicarboxylic acid component contains an aromatic dicarboxylic acid as a main component. A dicarboxylic acid component other than the aromatic dicarboxylic acid may be included. Examples of such a dicarboxylic acid component include ester derivatives such as aromatic dicarboxylic acids. The “main component” means that the proportion of aromatic dicarboxylic acid in the dicarboxylic acid component is 80% by mass or more.
Moreover, it is preferable that at least one aliphatic diol is used as the (B) diol component. The aliphatic diol can contain ethylene glycol, and preferably contains ethylene glycol as a main component. The main component means that the proportion of ethylene glycol in the diol component is 80% by mass or more.

The amount of the diol component (for example, ethylene glycol) is 1.015 to 1.50 mol per 1 mol of the dicarboxylic acid component (especially aromatic dicarboxylic acid (for example, terephthalic acid)) and, if necessary, its ester derivative. A range is preferred.

A conventionally known reaction catalyst can be used for the esterification reaction and / or transesterification reaction. Examples of the reaction catalyst include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium compounds, and phosphorus compounds. Usually, it is preferable to add an antimony compound, a germanium compound, or a titanium compound as a polymerization catalyst at an arbitrary stage before the polyester production method is completed. As such a method, for example, when a germanium compound is taken as an example, it is preferable to add the germanium compound powder as it is.

The maximum resin temperature _Tmax in the longitudinal direction (resin extrusion direction) in the twin screw extruder is the temperature of the raw material resin heated in the cylinder 10 in which the

screws

20A and 20B of the twin screw extruder 100 are disposed. When there is shearing heat generation, it is a temperature including a local high temperature portion due to the heat generation. T _max is obtained by measuring the resin temperature in the cylinder. T _max is preferably 300 ° C. or lower, more preferably 290 ° C. or lower, from the viewpoint of suppressing increase in terminal COOH. Further, the lower limit temperature of _Tmax is preferably 270 ° C. from the viewpoint of prevention of insufficient melting of the resin, that is, haze (white turbidity).

Further, by evacuating through the

vents

16A and 16B, volatile components such as moisture in the resin in the cylinder can be efficiently removed. If the vent pressure is too low, the molten resin may overflow from the cylinder 10, and if the vent pressure is too high, removal of volatile components may be insufficient, and hydrolysis of the resulting film may easily occur. From the viewpoints of preventing the molten resin from overflowing from the

vents

16A and 16B and selectively removing volatile components, the vent pressure is preferably 1.3 Pa to 6.67 × 10 ² Pa, and 1.3 Pa to 5.33 ×. 10 ² Pa is more preferable.

It is preferable that the average residence time from when the raw material resin is heated and melted in the cylinder to exit the extruder outlet 14 to be extruded from the forming die 40 into a sheet is 5 to 20 minutes. When the average residence time from when the raw material resin is heated and melted and after exiting the extruder outlet 14 of the extruder 100 until it is extruded from the molding die 40 is 5 minutes or longer, residual unmelted resin can be reduced. Further, when the average residence time is 20 minutes or less, an increase in the amount of terminal COOH due to thermal decomposition can be prevented, and more excellent hydrolysis resistance can be obtained. From such a viewpoint, the average residence time after the raw material resin is heated and melted and extruded from the extruder outlet 14 is more preferably 5 minutes to 15 minutes.
The average residence time is defined by the following formula.
Average residence time (seconds) = {Pipe volume on the downstream side of the extruder [cm ³ ] × Melt density [g / cm ³ ] × 3600/1000} / Extrusion amount [kg / h]

The thickness of the sheet is preferably 2 mm to 8 mm, more preferably 2.5 mm to 7 mm, and further preferably 3 mm to 6 mm. By increasing the thickness, the time required for the extruded melt to cool below the glass transition temperature (Tg) can be increased. During this time, COOH groups on the film surface are diffused into the polyester, and the amount of surface COOH can be reduced.

-Resin physical properties-
The terminal COOH amount (AV) of the sheet-like resin (particularly polyester) formed after melt extrusion is preferably 5 eq / t or more and 25 eq / t or less, more preferably 8 eq / t or more and 20 eq / t or less. Is 10 eq / t or more and 18 eq / t or less. When the terminal COOH amount is 25 eq / ton or less, the hydrolysis resistance is excellent and long-term durability is obtained. The amount of terminal COOH is desirably low from the viewpoint of hydrolysis resistance, but from the viewpoint of enhancing the adhesion when the film-formed sheet is closely attached to the adherend, the amount of the resin formed into a sheet after extrusion is The lower limit of AV is preferably 5 eq / ton.
“Eq / t” represents the molar equivalent per ton.

Further, the variation rate of the terminal COOH amount is preferably within ± 3% of the average value of the terminal COOH amount, more preferably within ± 2.0% of the average value of the terminal COOH amount, and further preferably, Within ± 1.0% of the average value.
Here, the average value of the amount of terminal COOH is a value obtained as follows.
Taking an arbitrary number (n) of 1 m samples every 200 m, with the start of winding for all roll lengths set to 0 m, each width direction is equally divided into five, and 5 cm × 5 cm sample pieces are cut out. And each sample piece is melt | dissolved in benzyl alcohol, the acid value of a solution is titrated with a KOH solution, the amount of terminal COOH is calculated | required, and the average of several (5n) terminal COOH amount is calculated | required.

(Second Embodiment)
A second embodiment of the twin-screw extruder of the present invention will be described with reference to FIG. The present embodiment has a system configuration that executes the intermittent water injection control routine in the first embodiment in the light of the haze of the formed resin film.

The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

Among the control routines by the control device 60 that is a resin temperature control means for controlling the biaxial extrusion device of the present embodiment, an intermittent water injection control routine for intermittently supplying water (refrigerant) to the refrigerant supply / exhaust port 37a of the cooling pipe. A mode in which the resin temperature is corrected in consideration of the haze value of the formed film will be described with reference to FIG.

When this routine is executed, the control from step 100 to step 200 is performed in the same manner as the control from step 100 to step 200 in the first embodiment. When the supply of the refrigerant to the refrigerant supply / exhaust port 37a is stopped in step 200, the haze of the resin film formed by the film forming apparatus 40 is measured in the next step 300.

The haze value is preferably 1.5% to 4.5%, more preferably 1.8% to 4.0%, and still more preferably 2.0% to 3.0%. The haze is a value measured by a haze meter (HZ-1 manufactured by Suga Test Instruments Co., Ltd.).

In the next step 320, it is determined whether or not the measured haze value exceeds a predetermined upper limit threshold value Q1. The range of the upper limit threshold value Q1 can be set to a lower limit value Q2 or more and 4.5% or less, and the preferable upper limit threshold value Q1 is more than the lower limit value Q2 and not more than 4.0%, which is a more preferable upper limit threshold value. The range exceeds the lower limit Q2 and is 3.0% or less.
When the haze is 4.5% or less, a quality with less unevenness is obtained, and good film forming suitability such as an increase in mechanical load and deterioration of brittleness can be obtained. In order to reduce haze, it is effective to increase the resin temperature, but the weather resistance may be impaired.

When it is determined in step 320 that the haze value exceeds the upper limit threshold Q1, the resin temperature is low and the resin may be crystallized, so that the set temperature t of the molten resin is changed to a higher temperature. Then, the process proceeds to the next step 360.

In step 320, when the haze value is equal to or less than the upper threshold Q1, the process proceeds to step 330. In step 330, it is determined whether or not the measured haze value is less than a predetermined lower threshold Q2. If it is determined in step 330 that the haze value is less than the lower limit threshold value Q2, there is a concern that the weather resistance will be impaired, so it is effective to lower the resin temperature, and the process proceeds to the next step 370. In step 370, the set temperature t of the molten resin is changed to a lower temperature within a range that does not impair the weather resistance.
Here, the preferable range of the lower limit threshold Q2 is 1.5% or more and 3.0% or less.

Thus, in this embodiment, since haze is suppressed to 1.5% or more and 4.5% or less, a film excellent in film forming suitability and excellent in weather resistance can be formed.

On the other hand, when it is determined that the haze value is equal to or lower than the upper limit threshold value Q1 in step 320 and further determined to be equal to or higher than the lower limit threshold value Q2 in the next step 330, there is no problem with the absolute value of the haze, but fluctuations occur. As a result, there is a risk of causing a variation in resin performance. Accordingly, in step 340, whether or not the absolute value of the fluctuation rate of the haze value of the formed resin film exceeds a predetermined threshold value Q3. Is determined.
Here, the absolute value of the fluctuation rate of the haze value refers to the absolute value of the difference between the measured haze value and the average value of the respective haze values. The threshold value Q3 can be 5% or less, the preferable threshold value Q3 is 3 or less, and the more preferable threshold value Q3 is 1 or less.
In other words, the fluctuation rate of the haze value is preferably within ± 5% of the average value of haze, more preferably within ± 3% of the average value of haze, and further preferably within ± 1% of the average value of haze.

In Step 340, when it is determined that the variation rate of the haze value exceeds the threshold value Q3, there is a possibility that there is a portion that is easily crystallized because the resin temperature is uneven and the resin temperature is partially low. Therefore, in the next step 380, the set temperature t of the molten resin is changed to a higher temperature within a range where the haze value is maintained at the upper limit threshold value Q1 or less.

Thereafter, in step 220, it is determined whether or not there is a request for stopping the operation of the twin-screw extruder, and when it is determined that a request for stopping the operation is not made, the temperature of the melted and kneaded molten resin is continuously maintained stably. Since it is necessary, the process proceeds to step 240. On the other hand, when it is determined in step 220 that the operation stop request has been made, it is not necessary to continuously control the resin temperature, and thus this routine is ended as it is.
If it is determined in step 340 that the variation rate of the haze value is equal to or less than the threshold value Q3, the process proceeds to step 220 as it is.

In step 240, it is determined whether the time from the start of supply in step 160 to the start of the next supply, that is, the refrigerant supply cycle has reached a predetermined cycle S set in advance. When it is determined in step 240 that the predetermined period S has been reached, the refrigerant is intermittently supplied in the predetermined period, so that the process returns to step 100 and the same control as described above is continued. . Here, when it is determined that the predetermined period S has not been reached, since intermittent supply in the predetermined period cannot be performed, the process waits until the predetermined period S, and when the period S is reached, the step 100 again. The control similar to the above is continued after returning to step S2.

(Third embodiment)
A third embodiment of the twin-screw extruder of the present invention will be described with reference to FIG. The present embodiment has a system configuration that executes the intermittent water injection control routine in the first embodiment in the light of whether or not the molten resin reaches the set temperature t.

Among the control routines by the control device 60 that is a resin temperature control means for controlling the biaxial extrusion device of the present embodiment, an intermittent water injection control routine for intermittently supplying water (refrigerant) to the refrigerant supply / exhaust port 37a of the cooling pipe. A mode in which the resin temperature is corrected in consideration of the relationship with the set temperature t of the molten resin will be described with reference to FIG.

When this routine is executed, the control from Step 100 to Step 120 is performed in the same manner as the control from Step 100 to Step 120 in the first embodiment. In step 120, if it is determined that the temperature difference Δt obtained by subtracting the set temperature t from the detected resin temperature is equal to or higher than the threshold temperature T, in step 400, the determination from the first step 120 after execution of this routine has elapsed. Start accumulating time.

In the next step 420, the accumulated time that has elapsed from the determination of the first step 120, whether or not exceeded the threshold time t ² it is determined. In step 420, when the integration time is determined to exceed the threshold time t ^2, since the resin temperature is in a situation where not reach the set temperature t of the molten resin that has been previously set, in step 440 Reduce the screw speed. Thereby, the effect that resin temperature falls more is anticipated.

In step 420, since when the integration time is determined to be the threshold time t ² below, intermittently a predetermined amount of the refrigerant predetermined may be continued supply time for supplying predetermined control, The process proceeds to step 140.

Subsequently, the control from step 140 to step 240 is performed similarly to the control from step 140 to 240 in the first embodiment.

As described above, the temperature variation of the molten resin can be further reduced by performing the refrigerant supply control and the screw rotation control.

(Fourth embodiment)
A fourth embodiment of the twin-screw extruder according to the present invention will be described with reference to FIGS. This embodiment has a system configuration in which the intermittent water injection control routine in the first embodiment is replaced with a flow switching control routine for switching the flow direction of the refrigerant in the cooling pipe. In addition, the same referential mark is attached | subjected to the component similar to 1st Embodiment, and the detailed description is abbreviate | omitted.

In the control routine by the control device 60 which is a resin temperature control means for controlling the twin-screw extrusion device of the present embodiment, the refrigerant to be circulated through the refrigerant flow path of the cooling pipe is supplied by switching the flow direction in the refrigerant flow path. The flow switching control routine will be mainly described with reference to FIGS.

When the power of the control device 60 is turned on by turning on the start switch of the film manufacturing apparatus of the present embodiment, the control system of the biaxial extrusion device 100A is started, and the intermittent water injection control routine is executed. Note that the system may be started manually in addition to being automatically performed.

By starting the film manufacturing apparatus, first, for example, the supply stop valve V1 provided in the cooling circulation system is opened, and the opening of the flow rate adjusting valve V3 is adjusted, so that the coolant supply / exhaust port 37a has water as a coolant. Is adjusted to a supply amount range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg.

When this routine is executed, first, in step 500, the temperature of the molten resin is detected by the temperature detection sensor S1 in order to determine whether or not it is necessary to control the resin temperature. Next, in step 520, the detected resin temperature exceeds the preset set temperature t of the molten resin, and the temperature difference Δt obtained by subtracting the set temperature t from the detected resin temperature is the threshold temperature T. Whether it is less than or not is determined.

If it is determined in step 520 that the temperature difference Δt is equal to or higher than the threshold temperature T, the resin temperature is too high and the amount of terminal carboxyl groups increases, which may reduce the hydrolysis resistance of the resin to be formed. Then, the process proceeds to step 540, and the output of the water amount (refrigerant) is determined by PID control according to the deviation of the detected value of the resin temperature with respect to the set temperature. If it is determined in step 520 that the temperature difference Δt is less than the threshold temperature T, the process proceeds to step 620 because the resin temperature is not excessively increased and the amount of terminal carboxyl groups is unlikely to increase significantly.

In the next step 560, as shown in FIG. 10, the supply stop valve V1 is closed, the supply stop valve V2 is opened, and the opening degree of the flow rate adjustment valve V4 is adjusted. By switching the valves in this way, the refrigerant that has been supplied to the refrigerant supply / exhaust port 37a is supplied to the refrigerant supply / exhaust port 37b. Thereby, the temperature of the resin on the refrigerant supply / exhaust port 37b side, which is higher than that on the refrigerant supply / exhaust port 37a side, is lowered, so that the temperature of the molten resin is made uniform, and the temperature unevenness of the molten resin occurs. It is reduced.

Subsequently, in Step 580, the supply time is calculated from the cycle of supplying the refrigerant, the output required for cooling, and the control constant, and it is determined whether or not the supply time of the refrigerant has passed. If it is determined in step 580 that the refrigerant supply time has elapsed, the supply of refrigerant commensurate with the output required for cooling has been completed. Therefore, in the next step 600, the supply stop valve V2 is closed and the circulation pump is stopped. As a result, the supply of the refrigerant is stopped. At the same time, the flow rate adjusting valve V4 may be closed. At this time, the supply stop valve V2 and the flow rate adjustment valve V4 are also closed.

In Step 580, when it is determined that the supply time of the refrigerant has not yet elapsed, the supply of the refrigerant is continued until a predetermined supply time elapses.

Thereafter, in step 620, it is determined whether or not there is a request for stopping the operation of the twin-screw extruder, and when it is determined that a request for stopping the operation is not made, the temperature of the melted and kneaded molten resin is continuously maintained stably. Since it is necessary, the process proceeds to step 640. On the other hand, when it is determined in step 620 that the operation stop request has been made, it is not necessary to continuously control the resin temperature, and thus this routine is ended as it is.

In step 640, it is determined whether the time from the start of supply in step 160 to the start of the next supply, that is, the refrigerant supply cycle has reached a predetermined cycle S set in advance. If it is determined in step 640 that the predetermined period S has been reached, the refrigerant is intermittently supplied in the predetermined period, so that the process returns to step 500 and the same control as described above is continued. . Here, when it is determined that the predetermined cycle S has not been reached, since the intermittent supply in the predetermined cycle cannot be performed, the process waits until the predetermined cycle S, and when the cycle S is reached, the step 500 is performed again. The control similar to the above is continued after returning to step S2.

As described above, the temperature unevenness of the molten resin can be further reduced by performing the supply control of the refrigerant amount and the switching control of the flow direction of the refrigerant flowing in the cooling flow path.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

-Polyester production equipment-
As shown in FIG. 2, a polyester manufacturing apparatus having the same configuration as that in FIG. 1 is prepared, and a screw having the following configuration is provided in a cylinder 10 provided with a raw material supply port 12 and two vents 16 </ b> A and 16 </ b> B as an extruder. A double vent type co-rotating and meshing twin screw extruder equipped with 20A and 20B was prepared. The cylinder 10 is formed by providing a temperature controller 30 and also serving as a cylinder wall. The temperature controller 30 has nine zones (heating zones Z1 to Z7 and cooling zones Z8 to Z9) divided into nine in the screw rotation axis direction (cylinder longitudinal direction), and temperature control can be performed for each zone. it can. As shown in FIGS. 3 and 4, a cooling pipe 35 is embedded in the cylinder wall along the periphery of the cylinder 10.

<Configuration of twin screw extruder>
(A) Screw:
-Screw diameter D: 200mm
Length L [mm] / screw diameter D [mm]: 31.5 (Cylinder 1 zone width (length in the screw axis direction): 3.5 D)
・ Vent: 2 places ・ Screw shape:
Plasticization kneading section (neutral kneading 2D, reverse screw 1D) immediately before the first vent
Deaeration-promoting kneading section (neutral kneading 2D) just before the second vent
・ Screw rotation speed: 90rpm
(B) Discharge rate: 3000 kg / h
(C) Cylinder temperature Z1 zone: 60 ° C, Z2 zone: 270 ° C, Z3 zone: 270 ° C, Z4 zone: 270 ° C, Z5 zone: 270 ° C, Z6 zone: 270 ° C, Z7 zone: 270 ° C, Z8 zone: 270 ° C., Z9 zone: described in Table 1 below. Here, the Z1 zone is the first zone on the raw material supply port 12 side.
(D) PET metering machine: Screw type

As shown in FIG. 1, a gear pump 44, a metal fiber filter 42, and a molding die 40 having the following configuration are connected to the polyester manufacturing apparatus, as shown in FIG. 1, on the downstream side of the extruder outlet in the melt resin extrusion direction of the twin screw extruder. Has been. The set temperature of the heater 30 for heating the molding die 40 was 280 ° C., and the average residence time of the resin was 10 minutes.
<Configuration other than twin-screw extruder>
(F) Gear pump: 2-gear type (width: 500mm)
(G) Temperature detector:
The following two sensors are installed to control the amount of cooling water in the Z9 zone of the extruder (the part closest to the cylinder outlet) ・ Temperature detection sensor S1: Attached to the temperature detector 50 downstream of the cylinder outlet ・ Temperature detection sensor S2: Attached to the wall material of the cylinder (h) Filter: Sintered metal fiber filter (pore diameter 20 μm)
(I) Molding die: 4mm lip spacing

-Raw resin-
Pellet type: polyethylene terephthalate (melting point Tm: 257 ° C., glass transition temperature Tg ^Pol : 79 ° C., intrinsic viscosity IV: 0.78 dL / g, terminal COOH amount: 18 equivalents / ton, crystallized at 160 ° C. with a Henschel mixer ) Pellets (PET pellets)
Pellet size: average major axis = 4.5 mm, average minor axis = 1.8 mm, average length = 4.0 mm

-Manufacture of polyester film-
(Melting extrusion)
Using the above twin screw extruder, the PET pellets were put into a hopper. Prior to the injection of the PET pellets, the resin temperature and water content of the PET pellets were adjusted to 120 ° C. and 50 ppm by heating and drying the PET pellets in advance. And it melt-kneaded adjusting the temperature of a cylinder wall to the temperature shown in following Table 1, and extruded from the extruder exit. Melt extrusion was performed by adjusting the suction side pressure of the gear pump to 1.0 MPa. Subsequently, the melt (melt) extruded from the exit of the extruder was passed through a gear pump and a metal fiber filter (pore diameter: 20 μm), and then extruded from a forming die onto a cooling roll. The extruded melt was brought into close contact with a cooling roll using an electrostatic application method to produce an unstretched sheet. This cooling roll is provided with a hollow chill roll, and the temperature is adjusted by passing water as a heat medium in the chill roll. In addition, the humidity was adjusted to 30% RH by surrounding the conveyance area (air gap) from the exit of the forming die to the cooling roll, and introducing humidity-conditioned air into the enclosed area. The melt thickness was adjusted to 3000 μm by adjusting the extrusion amount of the twin screw extruder and the slit width of the molding die.

At this time, the cooling control conditions in the cylinder were adjusted as follows.
-Supply amount to the refrigerant supply / discharge port 37a: 0.001 to 0.150 L / kg of resin
-Refrigerant supply cycle: cycle described in Table 1 below-Supply method: intermittent supply in the above cycle-Water amount in one cycle (steady time) (seconds / time): Amount described in Table 1 below (control temperature relative to set temperature) The output of the water volume changes according to the deviation of

A polyester film having a thickness of 250 μm is obtained by biaxially stretching the unstretched sheet obtained by sticking to a cooling roll and solidifying as described above by sequentially performing longitudinal stretching and lateral stretching under the following conditions. Was made.
(A) Longitudinal stretching The unstretched film was stretched in the MD direction (conveying direction) through two pairs of nip rolls having different peripheral speeds. At this time, the preheating temperature was 80 ° C., the stretching temperature was 90 ° C., the stretching ratio was 3.4 times, and the stretching speed was 3000% / second.
(B) Transverse stretching After longitudinal stretching, transverse stretching was performed under the following conditions using a tenter.
<Condition>
-Preheating temperature: 110 ° C
-Stretching temperature: 120 ° C
-Stretch ratio: 3.8 times-Stretch speed: 70% / second

The stretched film after finishing the longitudinal stretching and the transverse stretching was heat-set under the following conditions. After heat setting, the tenter width was reduced and thermal relaxation was performed under the following conditions. After heat setting and heat relaxation, both ends of the polyester film were trimmed by 10 cm. Thereafter, extrusion (knurling) was performed at both ends with a width of 10 mm, and the film was wound up with a tension of 25 kg / m. The width was 1.3 m and the winding length was 1000 m.
<Heat setting conditions>
・ Heat setting temperature: 205 ℃
・ Heat setting time: 2 seconds <thermal relaxation conditions>
-Thermal relaxation temperature: 200 ° C
-Thermal relaxation rate: 5%

A biaxially stretched polyethylene terephthalate (PET) film was produced as described above.

-Evaluation-
The following measurements and evaluations were performed on the measurement of the cylinder temperature and the amount of water during film formation and the properties of the formed PET film. The results of measurement and evaluation are shown in Table 1 below.

(1) Measurement of cylinder temperature In the Z9 zone of the cylinder, a thermocouple is attached to the cylinder heater fixing bolt as shown in Fig. 11, and the temperatures of the upper, lower, left and right sides in the circumferential direction are measured. It was measured. The average value of the measured values was obtained and used as the cylinder temperature.

(2) Measurement of cylinder water amount A flow meter was attached to the refrigerant supply / exhaust port 37a of the cylinder, and the amount of water (refrigerant) supplied by one opening operation of the solenoid valve was calculated from the measured value of the flow meter.

(3) Terminal COOH amount As shown in FIG. 12, from the formed PET film, the start of winding in all roll lengths was set to 0 m, and a plurality of 1 m samples were taken every 200 m, and then each width direction was set to 5 etc. 5 pieces of 5 cm × 5 cm size samples were cut in each width direction. And this sample piece was melt | dissolved in benzyl alcohol, the acid value of the solution was titrated with a KOH solution, the terminal COOH amount was calculated | required, and the average of several terminal COOH amount was calculated | required.
“Variation” in Table 1 is the difference between the average value and the value farthest from this average value (the maximum value and the minimum value of all measurement points that are further from the average value). Show.

(4) Haze After taking a plurality of 1 m samples every 200 m from the formed PET film in the same manner as “(3) Terminal COOH amount”, each width direction is divided into five equal parts, Five 5 cm × 5 cm sample pieces were cut in the direction. And the haze value of each sample piece was measured using the haze meter (HZ-1 by Suga Test Instruments Co., Ltd.), and the average of multiple values was obtained.
“Variation” in Table 1 is the difference between the average value and the value farthest from this average value (the maximum value and the minimum value of all measurement points that are further from the average value). Show.

The

As shown in Table 1, in the Examples, PET films having less terminal COOH amount and superior weather resistance were obtained as compared with Comparative Examples while maintaining low haze.

The disclosures of Japanese application 2013-139304 and Japanese application 2014-037490 are incorporated herein by reference in their entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims

A cylinder having an extrusion port for extruding molten resin;
Two screws with an outer diameter of φ100 mm or more arranged rotatably in the cylinder;
A cooling system disposed in the cylinder wall, having a first refrigerant supply / exhaust port and a refrigerant flow path through which a refrigerant that exchanges heat with the molten resin in the cylinder flows;
Detecting the temperature of the molten resin, which is disposed downstream of the extrusion port of the cylinder and upstream of the film forming apparatus for forming the molten resin into a film, in the molten resin distribution direction, and extruded from the extrusion port Temperature detection means;
By adjusting the supply amount of the refrigerant to the first refrigerant supply / exhaust port, the temperature difference between the temperature of the molten resin detected by the temperature detecting means and the resin set temperature is set to a predetermined threshold value or less. Resin temperature control means to control;
A twin-screw extruder equipped with.
In the molten resin distribution direction, on the downstream side of the extrusion port of the cylinder, and on the upstream side of the film forming apparatus for forming a film of the molten resin, a resin distribution pipe through which the molten resin flows is provided.
The temperature detection means includes at least a temperature measuring part disposed at a position separated by 10 mm or more from the inner wall surface of the resin flow pipe in the pipe inner direction, and a damage preventing material for preventing the temperature measuring part from being damaged. Item 2. The twin-screw extruder according to item 1.
The twin-screw extrusion apparatus according to claim 1 or 2, wherein the refrigerant is a working fluid that exchanges heat with the molten resin by latent heat of vaporization.
The resin temperature control means adjusts the supply amount of the refrigerant to the first refrigerant supply / exhaust port in a range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg. The twin-screw extrusion apparatus of any one of Claims.
The twin-screw extruder according to any one of claims 1 to 4, wherein the refrigerant is water.
The resin temperature control means intermittently supplies the refrigerant to the first refrigerant supply / exhaust port at a period of 10 seconds / time to 120 seconds / time with a supply time of more than 0% and not more than 40%. 6. The twin-screw extruder according to claim 1, wherein the temperature difference between the temperature of the molten resin and the set temperature of the resin is controlled to be equal to or less than a predetermined threshold value by performing the operation.
The resin temperature control means is such that the haze value of the resin film formed by the film film forming apparatus exceeds a predetermined upper threshold Q1, or the variation rate of the haze value of the resin film formed by the film film forming apparatus is If it exceeds a predetermined threshold Q3, increase the resin set temperature,
The resin set temperature is lowered when the haze value of the resin film formed by the film forming apparatus is less than a predetermined lower threshold Q2. A shaft extrusion device.
The resin temperature control means, when the temperature difference between the temperature of the molten resin and the resin set temperature does not reach a predetermined threshold value or less within a predetermined time, by changing the rotational speed of the screw, The twin-screw extruder according to any one of claims 1 to 7, wherein the temperature of the molten resin is controlled to a resin set temperature.
The cooling system further includes a second refrigerant supply / exhaust port for discharging the refrigerant from the refrigerant flow path, and a flow switching valve for switching a flow direction of the refrigerant,
The resin temperature control means supplies the refrigerant to the first refrigerant supply / exhaust port by switching the flow switching valve, and discharges the refrigerant from the second refrigerant supply / exhaust port. The second cooling supplied to the second refrigerant supply / discharge port and discharged from the first refrigerant supply / discharge port is switched at a predetermined cycle. Twin screw extrusion equipment.
A step of melting the thermoplastic resin while controlling the temperature of the resin melted in a cylinder provided with two screws having an outer diameter of φ100 mm or more arranged rotatably;
A process of extruding a molten thermoplastic resin from a molding die into a film,
A step of solidifying the extruded thermoplastic resin on a cooling roll;
Have
In the melting step, the temperature of the molten resin extruded from the extrusion port of the cylinder is detected before the step of extruding into the film shape, and the temperature difference between the detected temperature of the molten resin and the resin set temperature is determined. The film manufacturing method of controlling below the predetermined threshold value by adjusting the supply amount of the refrigerant | coolant supplied to the cooling system arrange | positioned at the said cylinder wall.
The film manufacturing method according to claim 10, wherein the refrigerant is a working fluid that exchanges heat with the molten resin by latent heat of vaporization.
12. The film manufacturing method according to claim 10, wherein in the melting step, the supply amount of the refrigerant is adjusted in a range of 0.001 L / resin 1 kg to 0.150 L / resin 1 kg.
13. The film manufacturing method according to claim 10, wherein the refrigerant is water.
The melting step is performed by intermittently supplying the refrigerant to the cooling system at a cycle of 10 seconds / time to 120 seconds / time and with a supply time of more than 0% and 40% or less of the cycle. The film manufacturing method according to any one of claims 10 to 13, wherein the temperature difference between the resin temperature and the resin set temperature is controlled to be equal to or less than a predetermined threshold value.
In the melting step, the haze value of the resin film formed by the film forming apparatus exceeds a predetermined upper limit threshold Q1, or the variation rate of the haze value of the resin film formed by the film forming apparatus is previously set. If it exceeds the defined threshold Q3, increase the resin set temperature,
The film according to any one of claims 10 to 14, wherein the resin set temperature is decreased when the haze value of the resin film formed by the film forming apparatus is less than a predetermined lower threshold Q2. Production method.
The melting step is performed by changing the number of rotations of the screw when the temperature difference between the temperature of the molten resin and the resin set temperature does not reach a predetermined threshold value within a predetermined time. The film production method according to any one of claims 10 to 15, wherein the temperature of the resin is controlled to a resin set temperature.
The cooling system includes a first refrigerant supply / exhaust port, a refrigerant flow path through which the refrigerant flows, a second refrigerant supply / discharge port through which the refrigerant is discharged from the refrigerant flow path, and a flow switching valve that switches a flow direction of the refrigerant. And
In the melting step, by switching the flow switching valve, the first cooling for supplying the refrigerant to the first refrigerant supply / exhaust port and discharging the refrigerant from the second refrigerant supply / exhaust port, The second cooling that is supplied to the second refrigerant supply / exhaust port and discharged from the first refrigerant supply / exhaust port is switched at a predetermined cycle. Film manufacturing method.