JP4506629B2 - Method for producing thermoplastic resin film and thermoplastic resin film - Google Patents

Description

  The present invention relates to the production of a thermoplastic resin film (including the polyester film that is effectively used for applications such as magnetic recording media, thermal transfer materials, electrical insulating materials, release materials, packaging materials, etc., and the following films are the same). More particularly, the present invention relates to a method for producing a thermoplastic resin film using a device that applies a blowing to the film and separates the dust from the film and removes the dust by a suction effect before the turret winder process of winding the film. .

  Conventionally, in order to blow off foreign matter adhered to the film surface in the manufacturing process of thermoplastic resin film, normal air is blown to remove coarse deposits of about several tens of μm from the surface by the air knife effect. The fine dust of about several μm is firmly confined in the boundary layer generated by the high-speed air flow, so it is released together with ultrasonic waves. Furthermore, in order to ensure this effect, the foreign matter has been removed using a dust removing device that immediately sucks and collects the foreign matter separated from the film surface by vacuum and drives it out of the system. This is because when a thermoplastic resin film is produced, foreign matter adheres to the surface of the film, resulting in a magnetic material coating defect or vapor deposition defect in the magnetic recording medium application, and in a packaging material application in the printing process. This is because a printing defect occurs and an insulation defect occurs in an electrical insulation application, and in any case, the quality of the product is lowered.

  This dust removal device can be applied at any stage of film production after the molten polymer is formed into a sheet, but when the film is stretched and / or heat-treated using a hot air heating type tenter, etc., the film in the tenter Takes out from the tenter outlet because foreign substances derived from resin monomers and oligomers sublimated from the substrate, sublimates such as stabilizers and lubricants added to the resin, and fine fragments of the film adhere to the surface. It needs to be installed during the process.

  Factors that determine the foreign substance removal efficiency include the air spray pressure and the distance from the tip of the spray nozzle to the film. The air blowing pressure is usually 5 to 25 kPa, preferably 10 to 20 kPa, and is preferably used with high efficiency. Similarly, the distance to the latter film is usually 5 mm or less, preferably 1 to 3 mm.

The film removed by such a dust removing device is wound on a roll by a winder. In the winding device, winding is performed while performing tension control so that stable winding is performed. In this tension control method, a signal from a film tension detection means (dancer roll, tension pickup roll, etc.) disposed upstream of the winding device is passed to the control unit, and the control unit uses a shaft motor during film winding. In many cases, a speed command is issued to control the take-up shaft speed. In a 2-axis turret winder that performs such tension control, during winding, the winding shaft (old shaft) that is being wound is kept under tension control in the same way as during normal winding, and the turret is rotated for winding. Turn the film and move the film running toward the core to the vicinity of the new core set on the other winding shaft (new shaft) provided on the turret, so that the film contacts the core. Switch to constant torque control at the specified timing. On the other hand, the speed control of the new axis increases to the film traveling speed until the moving guide roll comes into contact with the film, and the tension is controlled. And take up the film.
Japanese Patent Laid-Open No. 09-164587 Japanese Unexamined Patent Publication No. 04-035925 JP 09-003697 A

  Conventionally, when a two-axis turret winder is used in the winding process, the turret is swung while winding a film on a winding core held on one winding shaft (old shaft) provided on the turret. , Move the traveling path of the film traveling toward the core to the vicinity of the new core set on the other winding shaft provided on the turret, and then move the traveling film to the new winding by the moving guide roll The film is moved so as to hold the core, and then the film is cut downstream of the new core to rewind.

  Here, the signal from the tension detection means (dancer roll, tension pick-up roll, etc.) of the film with tension placed upstream of the winding device is passed to the control unit, and the control unit sends the speed to the shaft motor during film winding. Many methods are used to issue commands and control the winding shaft speed. In a 2-axis turret winder that performs such tension control, during winding, the winding shaft (old shaft) that is being wound is kept under tension control in the same way as during normal winding, and the turret is rotated for winding. Turn the film and move the film running toward the core to the vicinity of the new core set on the other winding shaft (new shaft) provided on the turret, so that the film contacts the core. Switching to the constant torque control at the predetermined timing, while the speed control of the new axis is increased to the film traveling speed and the tension control is performed before the moving guide roll comes into contact with the film.

  However, the rotation of the turret at the time of rewinding or the cutter for film switching causes the film tension to change so that it cannot be absorbed by tension control, resulting in looseness or tension in the film.

  If the influence of the tension change affects the film passing through the dust removal device, it will try to return the tension after tensioning in the case of tension as well as tension. , Sticking to the vacuum port of the dust removal device, scraping the film surface, scratching the film surface, increasing the amount of adhered foreign matter by scraping powder, and there is a problem that the film may be torn by this sticking. About installation of an apparatus, it installed on the roll which can carry out stable conveyance without tension fluctuation.

  However, due to the improvement in film quality requirements, when additional dust removal equipment is installed later in the existing film manufacturing process, it is often possible to install the dust removal equipment only in places where tension fluctuations occur due to rewinding of the winder. When a dust removing device was installed there, the above problem occurred frequently.

  Then, the objective of this invention is providing the manufacturing method which manufactures a thermoplastic resin film stably by solving the problem of the said prior art and adjusting the air pressure with respect to a film from a dust removal apparatus.

In order to achieve the above object, the present invention employs the following configuration. That is, the method for producing the thermoplastic resin film of the present invention includes:
(1) Before winding the thermoplastic resin film with a biaxial turret winder, a device (hereinafter referred to as a dust removing device) is provided that blows the film to separate the dust and removes the separated dust by the suction effect. In the manufacturing process of the thermoplastic resin film , heat that reduces the vacuum capacity of the film by reducing the vacuum blower rotation speed of the dust remover at the timing of the core switching (hereinafter referred to as rewinding) with a winder. A method for producing a plastic resin film.
It is. Moreover, the manufacturing method of the thermoplastic resin film of the preferable aspect of this invention is the following.
(2) to monitor the tension in the filtration apparatus installed transport roll position, the vacuum blower rotational speed of the filtration apparatus by changes in tension as the range of the following formula (1), according to the above item (1) to perform the vacuum capacity control Manufacturing method of thermoplastic resin film.

N: Rewinding vacuum blower rotation speed N ₀ : Vacuum blower rotation speed during normal winding T ₀ : Tension during normal winding ΔT: Maximum transfer tension change during rewinding (winding tension-normal winding tension)
(3) The method for producing a thermoplastic resin film as described in (1) or (2) above, wherein the blowing is performed with ultrasonic pressure air.
It is.

  According to the method for producing a thermoplastic resin sheet of the present invention, due to the tension fluctuation caused by switching the winding core of the biaxial turret winder, the film surface is scraped by the vacuum port of the dust removing device, and the film surface is scratched. The thermoplastic resin film can be produced in a stable state where the adhered foreign matter is increased by the shaving powder and the film is not torn by this sticking.

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

  A film forming method will be described. The film is usually melt-extruded with the above thermoplastic resin, cooled and individualized on a casting drum to obtain an unstretched sheet, uniaxially stretched, if necessary, coated with a desired coating solution, dried, and then perpendicular to the uniaxial stretching direction. It is obtained by stretching and orientation in the direction of stretching and heat setting. The obtained film is wound up in a roll shape in the winding process. Melt extrusion is performed using a single type of thermoplastic resin, may be a short layer film, or coextruded with a rectangular feed block, etc., using different types of thermoplastic resin sheets, or two or more layers It is good also as a film. Biaxial stretching can be performed, for example, by sequential biaxial stretching or simultaneous biaxial stretching, but if desired, before stretching, it can be stretched again in the longitudinal or transverse direction or longitudinal and transverse directions to increase mechanical strength. It can also be a so-called strong type.

  Further, a specific surface form may be formed by applying and drying a coating liquid on one or both sides of the film. As described above, a desired coating solution is applied onto the film at the stage where stretching in the uniaxial direction is completed. As a coating method, any of a doctor blade method, a gravure method, a reverse roll method, and a metering bar method may be used.

  While the stretched film is transported to the winder by the transport roll (9), air is blown by the blowing blower (11) to release fine dust, and the foreign matter detached from the film surface is immediately sucked by the vacuum by the vacuum blower (10). A dust removal device (8) that collects and drives out of the system is installed at the upper 1-5mm position of the film to remove dust, and the 2-axis turret winder is attached to the winding core held on one winding shaft (1). Tension for controlling the winding tension by passing a signal from the wind tension detecting means (7) for the film disposed upstream of the winder to the control unit, and the control unit issues a speed command to the shaft drive motor during film winding. The contact roll (4) is brought into contact with the control and winding shaft, and the film is wound by surface pressure control that gives surface pressure during winding. The When the diameter of the wound film becomes large and it is necessary to rewind, the contact roll (4) is separated, the turret (3) starts to rotate, and rewinding is started. Move the traveling path of the film traveling toward the core to the vicinity of the new core set on the other winding shaft (2) provided on the turret (3), and then move the traveling film The new roll is moved so as to be held by the guide roll (5), and then the film is cut by a cutter (6) attached to the same frame as the moving guide roll (5) downstream of the new roll to perform rewinding.

  In the method of the present invention, the contact roll separation start is the rewind start as the rewind timing, the rewind is finished when the cutter (6) for cutting the film is inserted, and the time set by the timer from the end of the rewind Up to the rewind timing. The contact roll separation start signal and the cutter input signal are input to the dust removal device control CPU (13) from the winder control CPU or the detection sensor installed on the machine side.

During normal product winding, the vacuum blower (10) of the dust remover has sufficient dust removal capability, and the blower rotation speed at which the vacuum pressure enables stable film formation, taking into consideration the holding angle of the transport roll, etc. The operation is being performed at N ₀ , and the tension value is input to the dust removing device CPU (13) in advance for the transport tension.

After contact roller spaced start signal is input to the filtration apparatus control CPU (13), the difference between the detected tension value T and pre-input tension value T ₀ and conveying tension change [Delta] T. The transfer tension change ΔT is calculated as needed from the start of rewinding, and when the calculated result is the maximum from the start of rewinding, the blower rotation speed is calculated by (Equation 1), and the motor rotation speed changing means such as an inverter is calculated. To change the rotation speed of the vacuum blower. This is because when the tension decreases, the gripping force of the roll on the film decreases proportionally regardless of the angle at which the roll is held. The vacuum blower rotational speed is reduced so as not to change the ratio of the gripping force and the vacuum force of the roll by reducing the vacuum force of which the gripping force is reduced. As a result, the vacuum capacity from the dust removal device to the film can be reduced by the rate that the gripping force of the film transport roll caused by tension fluctuations decreases, and the gripping force of the film transport roll is always stronger. And the film is prevented from being sucked up by the dust removing device.

Rewinding is finished by inputting the cutter input signal from the winder, but there may still be the effect of tension fluctuation during rewinding, so it is preferable to set the time from the timing of cutter insertion. Leave the vacuum blower speed changed for tens of seconds. This time needs to be determined from the state of tension fluctuation setting. Returning the rotational speed of the time after the vacuum blower to N _0.

  The method of the present invention is usually effective in a dust removing device for blowing and suctioning air, but the same effect can be obtained in a dust removing device for blowing and sucking ultrasonic air.

  When using the method of the present invention, the vacuum pressure of the vacuum blower is reduced, so that the dust removal function is reduced, but because of the change only at the time of rewinding, it hits the core part of the film wound up by the winder and removes the dust. The decline in capacity is not a problem at all. For this reason, it is preferable to have a function that issues an alarm when the difference from the tension value input in advance is greater than or equal to the set value other than the rewind timing.

  In the present invention, the thermoplastic resin is a resin that exhibits plasticity when heated, and typical resins (polymers) include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene α, β-dicarboxylate. , Polymers from P-hexahydro xylylene terephthalate, polymers from 1,4 cyclohexanedimethanol, poly-P-ethyleneoxybenzoate, polyarylate, polycarbonate and the like, and copolymers thereof as represented by Polyesters having ester bonds, and polyamides having admi bonds in the main chain as represented by nylon 6, nylon 66, nylon 610, nylon 12, nylon 11, etc., polyethylene, polypropylene, ethylene vinyl acetate copolymer , Poly Polyolefins mainly composed of hydrocarbons such as methylpentene, polybutene, polyisobutylene, polystyrene, etc., polyethersulfone (PES), polyphenylene oxide (PPO), polyetheretherketone (PEEK), polyethylene oxide, Polyethers represented by polypropylene oxide, polyoxymethylene, etc., halogenated polymers represented by polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polychlorotrifluoroethylene and polyphenylene sulfide (PPS), Polysulfone and their copolymers and modified products.

  In the case of the present invention, as the thermoplastic polymer, polyesters, polyamides, polyethers, polyphenylene sulfide and the like are particularly preferable, and polyesters such as polyethylene terephthalate and polyethylene naphthalate and polyphenylene sulfide are particularly preferable in the present invention. This effect is remarkable and is more preferable. Of course, known additives such as stabilizers, viscosity modifiers, antioxidants, antistatic agents, antiblocking agents, ultraviolet absorbers, infrared absorbers and the like may be added to the above-described polymer as necessary.

  The result of producing a thermoplastic resin film using the above thermoplastic resin film production apparatus will be described.

Example 1
An ethylene glycol slurry containing crosslinked polystyrene particles having an average particle diameter of 0.3 μm and calcium carbonate particles having an average particle diameter of 1.2 μm was prepared, and the ethylene glycol slurry was heat-treated at 190 ° C. for 1.5 hours, and then dimethyl terephthalate. After the ester exchange reaction, polycondensation was performed to produce a PET chip containing 2% by weight of crosslinked polystyrene particles and 1% by weight of calcium carbonate. A chip (polyester raw material) having an intrinsic viscosity of 0.65 substantially free of particles obtained by a conventional method was produced and used as a raw material for the sheet.

The polyester was melted with an extruder, extruded from a die at a temperature of 290 ° C., and rapidly cooled and solidified on a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method to produce an unstretched film. At this time, as the width of the base, a narrow base whose width direction stretch ratio in the final stenter can be taken up to 4 times the final exit width was used. Moreover, the discharge amount of the extruder was adjusted so that the final polyester film had a thickness of 38 μm. The unstretched film is stretched 3.5 times in the longitudinal direction at 112 ° C., stretched 4.8 times in the width direction at 110 ° C., and then heat-treated at 246 ° C. to give a thermoplastic resin film having a width of 2.5 m. (Biaxially stretched polyester film) was obtained. A thermoplastic resin film is transported by a transport roll, tension detection means is attached to a transport roll with a holding angle of 60 ° in the middle, a tension during transport is 150 N, a blowing air pressure of 25 kPa, and a vacuum air pressure of 5 kPa. Dust was removed by installing an ultrasonic dust removal device with a mouth of 0.04 m ² at a position of 2 mm on the film, and it was continuously wound up by a biaxial turret winder.

  As for the air pressure of the dust remover, the blowing is a 45kW blower with an inverter, and the vacuum is a 30kW blower with an inverter. Is adjusted to 25 kPa and the vacuum air pressure to 5 kPa.

In this state, when the winder was rewinded, the tension variation as shown in FIG. 4 occurred.
The rotational speed change time timer after entering the cutter was set to 60 seconds, and the vacuum blower was stopped using the dust removing apparatus of the present invention to obtain a thermoplastic resin film.

Displacement sensors are installed in the dust remover every 20 cm, the distance between the dust remover and the film is measured, and the contact status between the film and the dust remover is confirmed 10 times by rewinding 5 times with a CCD camera from both sides of the roll. It was carried out at the rewind timing.
Furthermore, scratches on the film surface and the number of adhered foreign matters of 5 μm or more on the film immediately after the rewinding timing were confirmed.

(Example 2)
Blower rotation speed at winder rewind timing

A thermoplastic resin film was obtained in the same manner as in Example 1 except that the number of revolutions was changed to that shown in FIG.

(Example 3)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the blower rotation speed was changed to 900 rpm at the winder rewind timing.

(Comparative example)
Even if the tension was changed, a thermoplastic resin film was obtained in the same manner as in Example 1 except that the vacuum blower rotation speed was kept at 1800 rpm.

It is the schematic of this invention system. It is a control flowchart of the vacuum blower of this invention system. It is a vacuum blower rotation speed calculation flowchart of the present invention system. Tension fluctuation when rewinding winder Vacuum blower rotation speed when rewinding winder

Explanation of symbols

1 Film winding axis (during winding)
2 Film take-up shaft (standby)
3 Turret 4 Contact Roll 5 Moving Guide Roll 6 Cutter 7 Winding Tension Detection Means 8 Dust Removal Device 9 Transport Roll 10 Vacuum Blower 11 Blowing Blower 12 Transport Tension Detection Means 13 Dust Removal Device CPU

Claims (4)

Before winding up the thermoplastic resin film with a twin-screw turret winder, a thermoplastic resin is provided with a device (hereinafter referred to as a dust removal device) that blows the film, separates the dust, and removes the separated dust by a suction effect. A thermoplastic resin film that reduces the vacuum capacity of the film by reducing the vacuum blower rotation speed of the dust remover at the timing of switching the core with a winder (hereinafter referred to as rewinding) in the film manufacturing process. Manufacturing method. 2. The production of a thermoplastic resin film according to claim 1, wherein the tension at the dust removing device installation conveyance roll position is monitored, and the vacuum blower rotation speed of the dust removing device is set within the range of the following formula 1 according to the change in tension to control the vacuum capacity. Method.

N: Vacuum blower rotation speed N ₀ : Vacuum blower rotation speed during normal winding T ₀ : Tension during normal winding ΔT: Change in winding tension during rewinding (winding tension-normal winding tension)   The method for producing a thermoplastic resin film according to claim 1 or 2, wherein the blowing is performed with ultrasonic pressure air.   The thermoplastic resin film manufactured with the manufacturing method in any one of Claims 1-3.

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