JP2014193604A - Manufacturing method of a sheet and manufacturing apparatus of a sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a sheet and a manufacturing apparatus of a sheet each used for homogenizing characteristics of the sheet varying due to various factors.SOLUTION: In the provided manufacturing method of a sheet, on an occasion where a polymer is melted within an extruder 1 and extruded, following the transportation of the molten polymer by a gear pump 2 whose rotation frequency is being controlled at a fixed level, from a nozzle 4 in the shape of a sheet and where the extruded sheet 10 is wound past cooling and molding steps, a given characteristic of the sheet 10 is measured at a step on the downstream side of the nozzle 4, and the screw rotation frequency of the extruder 1 and/or the heater temperature of the extruder is controlled depending on the value of the sheet characteristic thus measured.

Description

  The present invention relates to a sheet manufacturing method and a sheet manufacturing apparatus.

  Conventionally, a sheet manufactured using polyester, polyethylene, polypropylene, polyamide, polycarbonate, polyolefin, acrylic resin or the like is generally manufactured by a process as shown in FIG. FIG. 5 is a schematic diagram illustrating an example of a sheet manufacturing apparatus.

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

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

  In the manufacture of the sheet, it is important to make the properties of the resulting product sheet uniform. The properties mentioned here are the individual properties required for various product sheets such as sheet thickness, heat yield, specific gravity (density), crystallinity, optical transparency, and reflectivity. It is not limited to.

  In the width direction of the sheet, as described above, the amount of slit operation of the die is calculated from the variation in sheet thickness and fed back to the operation of the die, so that the thickness can be managed uniformly, and the width direction temperature and wind speed in the transverse stretching process. Uniform distribution of heat distribution and optical transparency in the width direction.

  In the sheet conveying direction, the conditions such as thickness variation and density are managed to be uniform by manipulating the conditions of the take-up speed, the longitudinal draw ratio, and the temperature in the casting process. Specifically, if the take-up speed of the casting process is not set according to the type of polymer, variations in thickness will occur due to vibration phenomenon, and in longitudinal stretching, if the magnification and temperature are not within the appropriate range, it will lead to sheet tearing There is.

  As described above, in principle, measures for variation in sheet thickness and characteristics are basically determined by investigating the cause of each process and solving it individually. However, according to the knowledge of the present inventors, in addition to stabilizing the individual processes, it is important to stabilize the extrusion process upstream from the die. This is because the sheet manufacturing process is continuous through the polymer, and the influence of the extrusion process, that is, the upstream process, directly affects the downstream process of casting and stretching. In light of the previous case, even if the take-up speed was optimized in the casting process, if there were variations in the viscosity, kneadability, and molten state of the polymer, uniform take-up would be difficult, resulting in variations in thickness and characteristics. Will occur. This is the same in the stretching process.

  The extrusion process is a process in which heat is applied to the polymer by a heating element such as a shear and a heating body such as a heater to melt the polymer, the melt is transported, foreign matter is removed in some cases, and the polymer is discharged in a sheet form. Factors that cause variations in sheet thickness and properties in the extrusion process include, for example, the melt state, viscosity variation, temperature variation, degradation state, molecular weight distribution, etc. of the polymer. In addition, it is necessary to manage the kneading degree of the polymer and the temperature of the molten polymer at a constant value in order to produce a uniform sheet. Patent Document 1 describes that it is important to stabilize extrusion, and it is necessary to operate in a state where the conditions of the extruder are in the stable region. Furthermore, it is important to keep the operating conditions of the extruder constant even when the polymer is discharged out of the system when the discharge range is different from the conditions of the stable operation of the extrusion due to the sheet manufacturing conditions. The contents are described.

JP 2012-183691 A

  However, as described in Patent Document 1, even when the apparatus and conditions of the extruder are stabilized, the sheet characteristics are often not uniform. For example, even in a factory that apparently manages the temperature in the room, the conditions of the extruder and peripheral devices change due to the influence of seasonal fluctuations and the temperature change during the day and night. In addition, there may be variations in properties such as viscosity and specific gravity of the received raw material, often directly affecting the extrusion conditions and further the physical properties of the sheet, and it is often impossible to obtain a sheet with uniform characteristics. . In the method of operating the discharge amount according to the sheet manufacturing conditions by setting the extrusion conditions to a stable range unique to the apparatus as in Patent Document 1, since the extrusion conditions do not change, the dispersion of the polymer directly affects the characteristics of the sheet. Therefore, it is difficult to suppress variations in the sheet due to external causes.

  An object of the present invention is to provide a sheet manufacturing method and a sheet manufacturing apparatus capable of measuring the sheet characteristics and feeding back to the operating conditions and set values of the extruder to make the sheet characteristics uniform. .

The manufacturing method of the sheet of the present invention that achieves the above-mentioned object
When the polymer is melted by an extruder, the melted polymer is transported by a gear pump controlled at a constant rotation speed and extruded from the die into a sheet, and when the extruded sheet is wound through a cooling molding process,
Sheet characteristics are measured in a process downstream from the die, and the number of rotations of the extruder screw and / or the heater temperature of the extruder is controlled according to the measured value of the sheet characteristics.

Moreover, the manufacturing method of the sheet | seat of another aspect of this invention is as follows.
When the polymer is melted by an extruder, the melted polymer is transported by a gear pump controlled at a constant rotation speed and extruded from the die into a sheet, and when the extruded sheet is wound through a cooling molding process,
Measure the characteristics of the sheet in a process downstream from the die, measure the pressure of the molten polymer between the extruder and the gear pump, determine the set value of this pressure according to the value of the measured sheet characteristics, The number of rotations of the screw of the extruder and / or the temperature of the heater of the extruder is controlled so that the pressure becomes this set value.

In addition, a method for producing a sheet according to still another aspect of the present invention is as follows.
When the polymer is melted by an extruder, the melted polymer is transported by a gear pump controlled at a constant rotation speed and extruded from the die into a sheet, and when the extruded sheet is wound through a cooling molding process,
Measure the sheet characteristics in a process downstream from the die, measure the pressure of the molten polymer between the gear pump and the die, determine the set value of this pressure according to the value of the measured sheet property, The number of rotations of the screw of the extruder and / or the temperature of the heater of the extruder is controlled so that the pressure becomes this set value.

An apparatus for producing a sheet of the present invention that achieves the above object is as follows.
An extruder for melting the polymer, a gear pump for quantifying the discharge, a base for widening the molten polymer into a sheet, a measuring device for measuring the characteristics of the sheet being conveyed, and this measuring device And an arithmetic unit for controlling the number of rotations of the screw of the extruder and / or the heater temperature of the extruder based on the measurement result.

Moreover, the sheet manufacturing apparatus according to another aspect of the present invention includes:
An extruder for melting the polymer, a gear pump for quantifying the discharge, a pressure gauge for measuring the pressure of the molten polymer between the extruder and the gear pump, and a base for widening the molten polymer in a sheet form A measuring instrument that measures the characteristics of the sheet that is being conveyed, a first calculator that determines a setting value of the pressure gauge based on a measurement result of the measuring instrument, and a pressure value of the pressure gauge is the setting And a second computing unit that controls the number of rotations of the screw of the extruder and / or the heater temperature of the extruder so as to obtain a value.

Moreover, the sheet manufacturing apparatus according to still another aspect of the present invention includes:
An extruder for melting the polymer, a gear pump for quantifying the discharge, a base for widening the molten polymer into a sheet, and a pressure gauge for measuring the pressure of the molten polymer between the gear pump and the base; A measuring instrument for measuring the characteristics of the sheet being conveyed; a first calculator for determining a set value of the pressure gauge based on a measurement result of the measuring instrument; and a pressure value of the pressure gauge is the set value And a second calculator for controlling the number of rotations of the screw of the extruder and / or the heater temperature of the extruder.

  According to the present invention, as shown below, by measuring the sheet characteristics and feeding back to the extrusion conditions, the sheet characteristics can be made closer to uniform, and the sheet can be manufactured stably. .

It is a schematic block diagram of the sheet manufacturing apparatus which shows one Embodiment of this invention. It is a schematic block diagram of the sheet manufacturing apparatus which shows one Embodiment of this invention. It is a schematic block diagram of the sheet manufacturing apparatus which shows one Embodiment of this invention. It is a schematic block diagram of the sheet manufacturing apparatus which shows one Embodiment of this invention. It is a schematic block diagram of a general sheet manufacturing apparatus.

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

  FIG. 1 is a schematic view of a sheet manufacturing apparatus showing an embodiment of the present invention. Here, 11 is a sheet characteristic measuring instrument, which measures the characteristics of various sheets. Reference numeral 12 denotes an arithmetic unit that calculates a characteristic variation from the value measured by the sheet characteristic measuring unit 11 and transmits a signal for operating the screw speed of the extruder and the heater temperature. Reference numeral 13 denotes an extruder screw rotation number signal, reference numeral 14 denotes an extruder heater temperature signal, and reference numeral 15 denotes a motor for rotating the screw. The base 4 and the cooling roll 5 are the same as those shown in FIG.

  In the configuration of FIG. 1, the characteristics of the sheet are measured immediately before winding the sheet. The place to be measured is not limited depending on the type of characteristics, but in order to make the thickness of the product and variations in characteristics uniform, it is preferable to immediately before winding the sheet formed as a product. Of course, it may be measured between the cooling roll 5 and the stretching step 6, or may be measured between the base 4 and the cooling roll 5.

  Further, the measuring device may be installed at one place in the width direction of the sheet and measure a fixed point, or may be measured by scanning the measuring device in the width direction. Furthermore, the structure provided with several measuring devices in the width direction may be sufficient.

  The measurement interval is preferably measured continuously at short intervals. The interval is preferably 1 second or less, and more preferably, the measurement is continued in the range of 0.01 seconds to 0.1 seconds. Of course, the measurement interval may be changed depending on the characteristics to be measured and the sheet conveyance speed.

  The measured characteristic value is taken into the arithmetic unit 12 and the variation is analyzed. From the result of the analysis, the calculator can be used to change, or control, the screw speed of the extruder, the heater temperature of the extruder, or both the screw speed and the heater temperature so that the characteristic variation is uniform. A signal is transmitted from 12 to the screw rotation motor 15 or a heater of the extruder 1 (not shown).

  Although the operation method for making the variation uniform varies depending on each property, as described above, factors that cause variation in the thickness and properties of the sheet in the extrusion process include, for example, the melt state, viscosity variation, temperature variation, Examples include deterioration state and molecular weight distribution. These factors are not independent, but are correlated with each other. In an extruder, the factors change with the number of rotations of the screw, shape, residence time, heater temperature, etc. It is preferable to operate the machine. In order to improve kneadability, it is necessary to improve the work (specific energy) for the extruder to knead the polymer per unit discharge amount, and increasing the screw rotation speed is an operation. In addition, the polymer tends to generate heat when subjected to shearing. However, if the screw rotation speed is increased, shearing heat generation occurs, the polymer temperature increases, the polymer viscosity decreases, and the kneading becomes difficult. It is preferable to operate in the direction of lowering the heater temperature. Further, the effect of improving the kneadability can be obtained only by the operation of the heater temperature without the operation of the screw rotation speed. In this case, although it depends on the characteristics of the polymer, it is preferable to operate in the direction of lowering. That is, it is preferable to perform an operation for increasing the number of rotations of the screw of the extruder, an operation for lowering the temperature of the heater of the extruder, or both of these operations when there is a large variation in the sheet characteristic distribution. Here, the extruder 1 may be a single-screw extruder, a tandem extruder in which single-screw extruders are connected in series, a twin-screw extruder, or a multi-screw extruder, or a combination thereof.

  As long as the screw of an extruder is a single axis | shaft structure, general full flight and double flight may be sufficient, and the dull image for improving kneadability may be installed in the front-end | tip. Moreover, if it is the structure of a biaxial extruder, various elements, such as a conveyance element and a kneading element, can be used. In either case, it is preferable that the change in kneadability and the change in the discharge amount when the screw rotation speed is manipulated are small because the characteristics can be finely adjusted and the production conditions are hardly affected.

  Further, the heater of the extruder may be a general aluminum casting heater or a band heater, and the screw cylinder may be covered with a heat medium jacket from the viewpoint of uniformity. Cooling may be a form in which the entire cylinder may be cooled with water, a heat medium, air, or a structure that allows water to pass through the central axis of the screw.

  In general, when using a twin screw extruder, a gear pump is installed at the tip of the extruder to adjust the discharge amount. Therefore, the discharge capacity is hardly affected by the number of rotations of the screw, and the kneading of the polymer can be operated. A large degree of freedom is preferable for controlling the characteristics of the sheet. In single-shaft and tandem extruders, the discharge rate increases in proportion to the screw speed, but in this case as well, by installing a gear pump downstream in the discharge direction of the extruder, the discharge rate is made constant and the screw speed is controlled. It becomes a good form because it becomes possible.

  The gear pump may have two or three gears, and various types of gears having flat teeth and inclined teeth can be used. The discharge performance of the gear pump is determined by the clearance between the gear and the housing that houses the gear. If the clearance is wide, the discharge accuracy measured by the gear is generally deteriorated due to the pressure before and after the gear pump. . For this reason, when the screw rotation speed is changed, the pressure on the gear pump entry side changes, so that the clearance is preferably narrowed in order to maintain the accuracy of the discharge amount. Since the discharge performance of the gear pump becomes dull with respect to the front and back pressure, the range in which the screw rotation speed can be changed can be expanded.

  2 is a schematic view of a sheet manufacturing apparatus showing another embodiment of the present invention. Here, 16 is a pressure gauge for measuring the pressure on the gear pump entrance side, 17 is a second computing unit, and the other configurations are the same as those in FIG.

  In the configuration of FIG. 2, first, the pressure setting value on the gear pump entry side is calculated from the characteristic result measured by the sheet characteristic measuring device 11 so that the characteristic variation is uniform by the first calculator 12. Next, a signal for changing the pressure set value is transmitted from the first computing unit 12 to the pressure gauge 16. Next, the pressure gauge 16 transmits the current pressure value and pressure set value signals on the gear pump entry side to the second calculator 17. Next, the setting of both the screw speed of the extruder, the heater temperature of the extruder, or both the screw speed and the heater temperature is changed, that is, controlled so that the pressure value on the gear pump entrance side becomes the pressure installation value. 2 sends a signal to the screw rotation motor 15 and the heater of the extruder 1 (not shown). Such a two-stage configuration may be adopted. By adopting the configuration as shown in FIG. 2, it is possible to simultaneously perform a pressure operation in accordance with the characteristics of the gear pump, which is a preferable form for uniformizing sheet characteristics.

  3 is a schematic view of a sheet manufacturing apparatus showing still another embodiment of the present invention. Here, the pressure gauge 16 is installed downstream of the gear pump, and other configurations and control methods are the same as those in FIG. By taking in the pressure downstream of the gear pump in which the state of the polymer appears remarkably in the control, it becomes a preferable form for further uniforming the sheet characteristics. For example, when the temperature and viscosity of the polymer are the same, the larger the pressure loss at the base, that is, the higher the pressure downstream of the gear pump, the greater the discharge amount. Therefore, when the thickness of the sheet is reduced, it is preferable to increase the set pressure downstream of the gear pump.

  In the configuration of FIGS. 2 and 3, the pressure setting value signal is transmitted from the first computing unit 12 to the pressure gauge 16, but the pressure setting value is transmitted from the first computing unit 12 to the second computing unit 17. A signal may be transmitted. In this case, the second computing unit 17 performs control by comparing the signal value of the current pressure transmitted from the pressure gauge 16 with the pressure set value transmitted from the first computing unit 12.

  2 and 3, the first computing unit 12, the second computing unit 17, and the pressure gauge 16 are provided independently as separate devices. You may combine all the functions of a pressure gauge, or two or more functions.

  In the sheet manufacturing apparatus of the present invention, it is preferable to control the heater temperature of the gear pump in addition to the extruder screw rotation speed and the extruder heater temperature. The configuration of FIG. 4 is a schematic view of the sheet manufacturing apparatus shown in FIG. 1 and showing an embodiment in which the heater temperature of the gear pump is also controlled. Here, 18 is a schematic representation of the heater temperature signal of the gear pump, and the other configuration is the same as in FIG. The accuracy with which the gear pump makes the discharge rate constant is affected by the state of the polymer and the temperature. By controlling the heater temperature of the gear pump in accordance with changes in the screw speed of the extruder and the heater temperature of the extruder, that is, changes in the polymer state, by control, it becomes a preferable form for uniform sheet characteristics. Of course, the heater temperature of the gear pump may be further controlled by the sheet manufacturing apparatus shown in FIGS.

  Sheet characteristics can be measured by measuring various characteristics such as thickness distribution, specific gravity (density) distribution, light transmittance distribution, visible light reflectance distribution, and air permeability distribution in the sheet conveyance direction or width direction. Good. One type of measurement may be performed, or a plurality of the above characteristics may be measured simultaneously.

  When measuring the thickness, for example, a laser displacement meter (model LKG-15) manufactured by Keyence Corporation can be used to directly measure the thickness. In addition, there is a method in which the density distribution of the polymer is measured by the X-ray method and the β-ray method and converted into the thickness. However, in this case, there is no particular limitation as long as the variation can be evaluated in both the thickness form and the density form.

  By measuring the light transmittance and the like, the uniformity of the sheet characteristics can be evaluated. In this case, a light source may be installed on one side of the sheet, and the light intensity may be detected on the opposite surface. For example, the light transmission intensity may be measured using a defect detector (model Mujken series) manufactured by Nireco. May be.

  The uniformity of sheet characteristics can also be evaluated by measuring the visible light reflectance and the like. For example, it may be measured using a spectrometer (model QuestX) manufactured by Konica Minolta.

  For air permeability, an air nozzle may be installed on one side of the sheet, and the amount of air leakage from the opposite surface may be detected. For example, a continuous air permeability measuring device (model MicroPERM600 smart) manufactured by AVATORON, etc. You may measure using.

  The amount of change in operation, such as the screw speed setting of the extruder, the temperature setting of the heater of the extruder, and the temperature setting of the gear pump heater, is affected by the variation in characteristics. Good. It is preferable to operate within a range of preferably 20% or less, more preferably 10% or less.

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

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

  The polymer sheet obtained by the above-mentioned manufacturing method can be used for various purposes such as packaging applications such as packages and laminates, magnetic recording media applications such as digital video cameras, optical applications such as displays, semiconductor applications such as flexible substrates, and battery applications such as separators. It can be suitably used for industry and applications.

[Example 1]
A sheet manufacturing apparatus having the configuration shown in FIG. 1 was used, and the steps such as the cooling roll, the stretching apparatus, and the winder after the die were manufactured in the configuration shown in FIG. Polyethylene terephthalate was used as the polymer, the discharge rate was 500 kg / hr, and the extrusion temperature was 280 ° C. As the extruder, a φ90 single-screw extruder was used, and a gear pump having the same discharge performance was used. Use a die set to a width of 900 mm and a slit gap of 2.5 mm, a cooling roll with a diameter of 600 mm, a casting speed of 40 m / min, a longitudinal draw ratio of 5.0 times, a longitudinal draw temperature of 125 ° C., and a product sheet The sheet was produced at a speed of 200 m / min.

  The sheet characteristics are measured with a β-ray thickness gauge immediately before winding, and the screw rotation speed and heater temperature of the extruder are adjusted so that the variation in thickness in the conveying direction is 10% or less throughout the year. Controlled. As a result, it was possible to produce a product sheet having a thickness variation of 8.3% or less throughout the year, and to obtain a product of good quality without any other problems.

[Example 2]
The sheet manufacturing apparatus having the configuration shown in FIG. 2 was used, and the manufacturing process of the sheet was performed with the configuration shown in FIG. Polypropylene was used as the polymer, the discharge rate was 100 kg / hr, and the extrusion temperature was 240 ° C. As the extruder, a φ65 single-screw extruder was used, and a gear pump having the same discharge performance was used. Use a die set to a width of 700 mm and a slit gap of 1.1 mm, a cooling roll with a diameter of 800 mm, a casting speed of 27 m / min, a longitudinal draw ratio of 5.5 times, a longitudinal draw temperature of 115 ° C., and a product sheet The sheet was produced at a speed of 150 m / min.

  As for the sheet characteristics, the thickness measurement with a β-ray thickness gauge and the air permeability are measured immediately before winding, and the thickness variation in the conveying direction during the winter season (December to March) is 8. The pressure before the gear pump was controlled by the screw rotation speed and the heater temperature of the extruder so that the variation in air permeability was 10% or less so that it would be 0% or less. As a result, it is possible to manufacture a product sheet having a thickness variation of 5.6% and an air permeability variation of 9.2% or less during the period, and obtaining a good quality product with no other defects. I was able to.

[Example 3]
The sheet manufacturing apparatus having the configuration shown in FIG. 3 was used, and the steps such as the cooling roll, the stretching apparatus, and the winder after the die were manufactured in the configuration shown in FIG. Polyethylene terephthalate was used as the polymer, the discharge rate was 200 kg / hr, and the extrusion temperature was 290 ° C. The extruder used was a φ75 tandem extruder, and a gear pump having the same discharge performance was used. The die is 1100 mm wide and the slit gap is 1.5 mm. A cooling roll with a diameter of 700 mm is used. The casting speed is 30 m / min, the longitudinal draw ratio is 6.0 times, and the longitudinal draw temperature is 130 ° C. The sheet was produced at a speed of 180 m / min.

  The sheet was measured for thickness by a β-ray thickness gauge immediately before winding, so that the thickness variation in the conveyance direction during summer (July to September) was 6.0% or less. The set value of the pressure downstream of the gear pump was changed, and the pressure was controlled by the screw speed and the heater temperature of the extruder. As a result, a product sheet having a thickness variation of 5.0% or less during the period could be manufactured, and a product with good quality could be obtained without any other problems.

[Comparative Example 1]
The sheet was manufactured with the configuration shown in FIG. Polypropylene was used as the polymer, the discharge rate was 110 kg / hr, and the extrusion temperature was 240 ° C. As the extruder, a φ65 single-screw extruder was used, and a gear pump having the same discharge performance was used. Use a die set to a width of 700 mm and a slit gap of 1.1 mm, a cooling roll with a diameter of 800 mm, a casting speed of 34 m / min, a longitudinal draw ratio of 5.3 times, a longitudinal draw temperature of 118 ° C., and a product sheet The sheet was produced at a speed of 180 m / min.

  As a characteristic of the sheet, the thickness measurement with a β-ray thickness gauge and the air permeability were measured immediately before winding, and the variation was examined during the winter (December to March). 13.4% and air permeability variation was 15.6%, and a product sheet with target characteristic variation could not be obtained.

[Comparative Example 2]
Same as the conditions of Comparative Example 1, the longitudinal draw ratio was changed from 5.0 times to 5.4 times, and the casting speed was changed correspondingly, but the thickness variation was 15.5% to 17 The results varied between 6% and correlated with variations in thickness and physical properties.

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

DESCRIPTION OF SYMBOLS 1 Extruder 2 Gear pump 3 Filter 4 Cap 5 Cooling roll 6 Stretching device 7 Winder 8 Thickness meter 9 Thickness controller 10 Sheet 11 Sheet characteristic measuring instrument 12 (first) calculator 13 Extruder screw rotation speed signal 14 Extruder heater Temperature signal 15 Screw rotation motor 16 Pressure gauge 17 Second computing unit 30 Sheet manufacturing apparatus

Claims (11)

Melt the polymer in an extruder,
The melted polymer is transported by a gear pump whose rotational speed is controlled to a constant value and extruded from the die into a sheet,
In the sheet manufacturing method of winding the extruded sheet through a cooling molding step,
A sheet manufacturing method that measures sheet characteristics in a step downstream from the die and controls the screw speed of the extruder and / or the temperature of the heater of the extruder according to the measured sheet characteristic value. . Melt the polymer in an extruder,
The melted polymer is transported by a gear pump whose rotational speed is controlled to a constant value and extruded from the die into a sheet,
In the sheet manufacturing method of winding the extruded sheet through a cooling molding step,
Measure the characteristics of the sheet in a process downstream from the die, measure the pressure of the molten polymer between the extruder and the gear pump, determine the set value of this pressure according to the value of the measured sheet characteristics, A method for producing a sheet, wherein the number of rotations of the screw of the extruder and / or the temperature of the heater of the extruder is controlled so that the pressure becomes the set value. Melt the polymer in an extruder,
The melted polymer is transported by a gear pump whose rotational speed is controlled to a constant value and extruded from the die into a sheet,
In the sheet manufacturing method of winding the extruded sheet through a cooling molding step,
Measure the sheet characteristics in a process downstream from the die, measure the pressure of the molten polymer between the gear pump and the die, determine the set value of this pressure according to the value of the measured sheet property, A method for producing a sheet, wherein the number of revolutions of the screw of the extruder and / or the temperature of the heater of the extruder is controlled so that the pressure becomes the set value.   The sheet manufacturing method according to claim 1, wherein the temperature of the gear pump is controlled in addition to the number of rotations of the screw of the extruder and / or the temperature of the heater of the extruder.   The method for producing a sheet according to any one of claims 1 to 4, wherein the measurement of the characteristics of the sheet is performed before winding the sheet as a product.   The characteristic of the sheet is at least one selected from the group consisting of a thickness distribution, a specific gravity distribution, an air permeability distribution, and a light transmittance distribution in the sheet conveyance direction or width direction. Sheet manufacturing method.   The method for producing a sheet according to claim 6, wherein when the variation in the distribution of characteristics of the sheet is large, the number of rotations of the screw of the extruder is increased and / or the temperature of the heater of the extruder is decreased. An extruder for melting the polymer;
A gear pump to quantify the discharge;
A base for widening the molten polymer into a sheet,
A measuring instrument for measuring the characteristics of the sheet being conveyed;
An apparatus for manufacturing a sheet, comprising: an arithmetic unit that controls the number of rotations of the screw of the extruder and / or the heater temperature of the extruder based on a measurement result of the measuring device. An extruder for melting the polymer;
A gear pump to quantify the discharge;
A pressure gauge for measuring the pressure of the molten polymer between the extruder and the gear pump;
A base for widening the molten polymer into a sheet,
A measuring instrument for measuring the characteristics of the sheet being conveyed;
A first computing unit that determines a set value of the pressure gauge based on a measurement result of the measuring device;
A sheet manufacturing apparatus comprising: a second computing unit that controls a screw speed of the extruder and / or a heater temperature of the extruder so that a pressure value of the pressure gauge becomes the set value. An extruder for melting the polymer;
A gear pump to quantify the discharge;
A base for widening the molten polymer into a sheet,
A pressure gauge that measures the pressure of the molten polymer between the gear pump and the base;
A measuring instrument for measuring the characteristics of the sheet being conveyed;
A first computing unit that determines a set value of the pressure gauge based on a measurement result of the measuring device;
A sheet manufacturing apparatus comprising: a second computing unit that controls a screw speed of the extruder and / or a heater temperature of the extruder so that a pressure value of the pressure gauge becomes the set value.   The measuring device for measuring the characteristics of the sheet measures at least one selected from the group consisting of a thickness distribution, a specific gravity distribution, an air permeability distribution, and a light transmittance distribution in the sheet conveyance direction or width direction. 10 to 10 sheet manufacturing apparatus.

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