CN101450515A

CN101450515A - Apparatus for manufacturing thermoplastic resin film, and method for manufacturing thermoplastic resin film

Info

Publication number: CN101450515A
Application number: CNA2008101798263A
Authority: CN
Inventors: 则常雅彦
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2007-12-05
Filing date: 2008-12-05
Publication date: 2009-06-10
Anticipated expiration: 2028-12-05
Also published as: TWI477383B; TW200934643A; KR101632261B1; JP2009154518A; CN101450515B; KR20090059067A; JP5173476B2

Abstract

The invention provides an apparatus and method for manufacturing a thermoplastic resin film. The apparatus for manufacturing a thermoplastic resin film includes a die which discharges a molten thermoplastic resin as a film, a cooling roll which is arranged so as to oppose to the discharge port of the die, and cools and solidifies the discharged film, and a variation reduction mechanism which reduces a variation of a wind speed in the vicinity of the surface of the film. The apparatus enables to provide a thermoplastic resin film which is suitable for an optical application, by controlling the thickness nonuniformity of the thermoplastic resin film in manufacturing the thermoplastic resin film by using a melt film-forming method.

Description

The preparation equipment used of thermoplastic resin film and prepare the method that thermoplastic resin film is used

Technical field

The present invention relates to a kind of equipment and a kind of method that is used to prepare thermoplastic resin film that is used to prepare thermoplastic resin film, particularly relate to the technology of preparing of the thermoplastic resin film that is used for optical applications such as LCD.

Background technology

The thermoplastic resin of being made by celluosic resin, cyclic olefin base resin etc. is widely used as the film that is used for optical applications.Particularly, the thermoplastic resin of being made by celluosic resin and cyclic olefin base resin is used as the blooming that is used for LCD owing to have the transparency, toughness, optical isotropy etc.

The method that is used for preparing thermoplastic resin film comprises discharges from die head the molten thermoplastic resin with the form of film, and by using many chill rolls with film cooling of discharging and the method (for example being melt into embrane method) of solidifying.Use the thermoplastic resin film that does not stretch of this method preparation for example to be used as, be used to protect the film of LCD.By the thermoplastic resin film expanding that will not stretch and produce the phase shift films that the film that postpones is used as LCD.

The above-mentioned embrane method that is melt into has following point: the film of discharging from die head lands from die head at film and be subjected to the influence of the interference in gap (the air gap) easily before on the chill roll, and causes thickness offset.

As the countermeasure of this situation, for example, Japanese Patent Application Publication 2006-150806 has proposed to prevent that by the entire circumference with shading member encirclement die head and chill roll film is subjected to the method for the influence of the outer gas stream in the air gap.

Summary of the invention

Yet the method for describing in Japanese Patent Application Publication 2006-150806 is demonstrating certain effect aspect the thickness offset reducing, but can not be effectively and prevent from efficiently to disturb, and reason is not have analysis to cause the air-flow of thickness offset.

The present invention be directed to this situation design, and purpose is to provide a kind of method for preparing thermoplastic resin film, described method can be reduced in to use and be melt into the thickness offset that occurs when embrane method prepares thermoplastic resin film, and can obtain to be suitable for the thermoplastic resin film of optical applications.

The inventor finds, because die head is hot, the temperature difference between die head and chill roll raises, and for example, the conventional touch roll system of diagram in as Figure 23 to be used for illustrating, ascending air stream (arrow) appears at the two ends of film 6, rises towards die head 4, particularly, the both sides from the width in the space between chill roll 2 and the touch roll 3 rise.The wind speed that this ascending air conductance causes film near surface in the space between the surface of die head and chill roll changes, and causes the distribution (temperature non) in the lip-deep temperature of film.When producing Temperature Distribution on the film surface, distribution may cause the thickness offset that makes the film cooling and solidifying when on chill roll.

Therefore, in order to achieve the above object, the inventor provides a kind of equipment that is used to prepare thermoplastic resin film, and described equipment comprises: die head, and described die head is discharged the molten thermoplastic resin with the form of film; Chill roll, described chill roll are positioned to relative with the outlet of described die head, and the film of discharging is cooled off and solidifies; With change to reduce mechanism, described variation reduces mechanism and reduces by changing at the wind speed that the near surface of described film causes towards the ascending air stream of described die head.The wind speed that described equipment can use this mechanism to reduce and be caused by the ascending air stream towards described die head changes, and therefore can prepare the film of the thickness offset with reduction.

Changing and reduce mechanism can be masking device, described masking device is between the end on the width of end on the width of chill roll and film, film after the outlet of die head is discharged to landing before on the surface of chill roll, the end on the width of shielding film at least.Perhaps, change reducing mechanism can be the air fairing, described air fairing film after the outlet of die head is discharged to landing before on the surface of chill roll, the air of the near surface of film is carried out rectification.

A first aspect of the present invention provides a kind of equipment that is used to prepare thermoplastic resin film, and described equipment comprises: die head, and described die head is discharged the molten thermoplastic resin with the form of film; Chill roll, described chill roll are positioned to relative with the outlet of described die head, and the film of discharging is cooled off and solidifies; And masking device, described masking device between the end on the width of end on the width of chill roll and film, film after the outlet of die head is discharged to landing before on the surface of chill roll, the end on the width of shielding film at least.

According to a first aspect of the invention, masking device is between the end on the width of end on the width of chill roll and film, film after the outlet of die head is discharged to landing before on the surface of chill roll, the end on the width of shielding film at least.Thereby, film after the outlet of die head is discharged to landing before on the surface of chill roll, masking device can prevent that the ascending air stream and the near surface of film from colliding.Therefore, the masking device near surface that can be reduced in film causes the wind speed of thickness offset to change.

According to a second aspect of the invention, in the equipment according to first aspect, masking device is a shield, described shield with the direction of film surface approximate vertical on, be positioned between the end on the width of end on the width of chill roll and film.

The shield that has the end on the width of the film that is used to cover discharge according to the equipment of second aspect, described shield are positioned between the end on the width of end on the width of chill roll and film.Shield can prevent that the ascending air stream and the near surface of the film of discharging from colliding from die head.

According to a third aspect of the invention we, in the equipment according to second aspect, the distance between the end on the width of shield and film is below the 50mm.

In the equipment according to the third aspect, the distance between the side on the width of shield and film is narrow.Therefore, can improve its screening performance, simultaneously, can form hardly at the near surface of film from the ascending air stream of the surface guiding die head of chill roll.

According to a forth aspect of the invention, according to second or the equipment of the third aspect in, settle masking device with around the further encirclement film surface.Thereby masking device can prevent the face side collision of ascending air stream and film reliably, and can prevent to produce thickness offset.

According to a fifth aspect of the invention, in the equipment according to first aspect, masking device comprises: shell, and the space between the surface of described shell encirclement die head in the vertical and the surface of chill roll, and have the labyrinth type mechanism that forms therein; Form device with air-flow, described air-flow forms the air-flow of device on the direction of the surperficial approximate vertical of formation of the both ends on the width of shell and film.

Equipment according to the 5th aspect has shell, the space between the surface of described shell encirclement die head in the vertical and the surface of chill roll, and have the labyrinth type mechanism that forms therein.Therefore, described equipment can prevent that ascending air from flowing to the near surface that reaches the film of discharging from die head.In addition, the air-flow on the direction of described equipment formation and film surface approximate vertical, the ascending air that therefore can eliminate both ends inflow from the width direction flows.At this moment, air-flow is passed in the labyrinth type mechanism of enclosure.Therefore, the air-flow that is cushioned by labyrinth type mechanism does not disturb the air-flow at the near surface of film.The kind of air-flow is not limited to air, and for example can be, inert gas such as nitrogen.

According to a sixth aspect of the invention, in according to the equipment aspect the 5th, it is wind pushing nozzle or suction nozzle that described air-flow forms device.

Therefore, air-flow form device by use wind pushing nozzle or suction nozzle with the direction of the surperficial approximate vertical of film on form air-flow, therefore can cover the ascending air stream that the end from the width of film flows into.

In order to reach described purpose, the equipment that being used to according to a seventh aspect of the invention prepares thermoplastic resin film comprises: die head, and described die head is discharged the molten thermoplastic resin with the form of film; Chill roll, described chill roll are positioned to relative with the outlet of described die head, and the film of discharging is cooled off and solidifies; With the air fairing, described air fairing is positioned near the outlet of described die head, and described film after the outlet of die head is discharged to landing before on the surface of described chill roll, the air of the near surface of film is carried out rectification.

Equipment according to the 7th aspect has the air fairing, and described air fairing is positioned near the outlet of described die head, and the air of the near surface of the film of discharging is carried out rectification.Therefore,, carry out rectification, also reduced the wind speed variation by air-flow to the near surface of film even ascending air flows to the near surface that reaches film.For example comprise as the available apparatus of this air fairing and on the direction parallel, to carry the wind pushing nozzle of air or the vacuum draw nozzle of vacuum draw air etc. with the discharge direction of film.

According to an eighth aspect of the invention, in according to the equipment aspect the 7th, the air fairing is positioned near the outlet of described die head, and is to carry abreast with the discharge direction of film or the wind pushing nozzle or the suction nozzle of suction air.

According to a ninth aspect of the invention, according to first to the eight aspect the equipment of any also comprise: measurement mechanism, described measurement mechanism is measured the temperature at the near surface of film; And heater, described heater is heated to predetermined temperature based on measurement result with the near surface of film.

According to can raise atmosphere temperature around the die head of the equipment of the 9th aspect, and therefore can reduce the temperature difference between die head and the atmosphere.Therefore, this equipment can be so that produce ascending air stream hardly.The near surface of film specifically is meant from the film surface and is the zone below the 20mm.

Here, heater can be positioned in the masking device itself, perhaps in the inboard of masking device, and for example, can comprise heater is embedded method in the masking device itself.

According to the tenth aspect of the invention, in according to any described equipment in aspect first to the 9th, the air gap that lands between the lip-deep point of described chill roll at the outlet and the described film of described die head is below the 200mm.

In according to the equipment aspect the tenth, the air gap can be controlled to be below the 200mm.Therefore, can reduce the area that is interfered as the film of outer gas stream influence.Therefore, this equipment can prevent to produce thickness offset.

According to an eleventh aspect of the invention, also comprise according to each equipment in first to the tenth aspect: with the touch roll that described chill roll is adjacent to settle, the outlet of wherein said die head is positioned in than any one the lower position in the summit of the summit of described chill roll and described touch roll.

In according to the described equipment of the tenth one side, the outlet of described die head is positioned in than any one the lower position in the summit of the summit of described chill roll and described touch roll.Therefore, the both sides of having covered the film of from die head, discharging by chill roll and touch roll, and can be so that ascending air stream collide with film hardly.

In order to reach described purpose, the method that being used for according to a twelfth aspect of the invention prepares thermoplastic resin film comprises the following steps: to use according to first to the tenth any described equipment that is used to prepare thermoplastic resin film on the one hand, and the wind speed that reduces the near surface of film changes.

Method according to the 12 aspect comprises that use is according to any described equipment that is used to prepare thermoplastic resin film in first to the tenth one side.Therefore, can cover ascending air stream, perhaps can carry out rectification air at the near surface of film towards the near surface of film.Therefore, can prevent the generation of distribution (inhomogeneities) of wind speed of the near surface of film, perhaps can reduce the distribution (inhomogeneities) of wind speed.

In order to reach described purpose, a third aspect of the present invention provides a kind of method that is used to prepare thermoplastic resin film, and described method comprises the following steps: molten thermoplastic resin's form with film from die head is discharged; The film of discharging is cooled off on chill roll and solidifies; Change with the wind speed of the near surface of the film that will discharge and to be controlled to be below 0.5 meter per second.

The wind speed that has caused the near surface of the film between die head and chill roll surface at the ascending air conductance shown in Figure 23 changes, and becomes the reason that causes the lip-deep Temperature Distribution of film (inhomogeneities).When this Temperature Distribution on the film surface, occurring, the thickness offset when this distribution may cause on chill roll cooling and solidify molten resin.In according to described method aspect the 13, wind speed changed being controlled to be below 0.5 meter per second, thereby can prevent to cause the appearance of the Temperature Distribution of above-mentioned thickness offset.

According to a fourteenth aspect of the invention, also comprise the following steps: after described film is discharged from die head to landing before on the surface of described chill roll, the air of the near surface of film is carried out rectification according to the method for the 13 aspect.

According to a fifteenth aspect of the invention, in according to described method aspect the 14, by carrying abreast with the discharge direction of described film or suction air carries out the air rectification.

According to a sixteenth aspect of the invention, comprise also that according to the method for any in the 13 to the 15 aspect wind speed with the near surface of film is controlled to be the step below 1 meter per second.

According to the method for the 16 aspect the wind speed of the near surface of film is controlled to be little value, therefore can controls the thickness offset that causes by Influences on Wind Velocity.

In a seventeenth aspect of the present invention, the near surface of film in any method in the 13 to the 16 aspect and the temperature difference between the die head are controlled in the scope below 160 ℃.

According to the method for the 17 aspect the difference between the temperature of the atmosphere temperature of the near surface of film and die head is controlled in the scope below 160 ℃, therefore can be so that produce the ascending air stream that is derived from the difference between die head temperature and the atmosphere temperature hardly.

According to an eighteenth aspect of the invention, in according to any described method in aspect the 13 to the 17, described chill roll is the contact roll shape.

In this touch roll system, chill roll can be fully to the surface pressurization of the fused film of from die head, discharging, therefore can reduce the inhomogeneities of Re and Rth, and the inhomogeneities in the plane is whole.

According to a nineteenth aspect of the invention, in according to the 13 to the tenth eight aspect in any described method, the temperature of the molten resin after will be just from described die head, discharging be defined as T (℃) time, more than (T-10) ℃ and in the temperature range below T ℃, described thermoplastic resin has with absolute value counts viscosity gradient more than 1.7Pas/ ℃ at described thermoplastic resin.

Method according to the 19 aspect applies the present invention to thermoplastic resin, the temperature of the molten resin of this thermoplastic resin after will be just from described die head, discharging be defined as T (℃) time,, have with absolute value and count viscosity gradient more than 1.7Pas/ ℃ more than (T-10) ℃ and in the temperature range below T ℃ at this thermoplastic resin.The dependent resin of high-temperature with melt viscosity is subjected to changing the influence of temperature variation that causes by wind speed easily, has therefore changed viscosity greatly, thereby has trended towards causing thickness offset.In this case, the method according to this invention produces ascending air stream hardly by making, can significantly suppress thickness offset.

According to a twentieth aspect of the invention, in according to any described method in aspect the 13 to the 19, described thermoplastic resin is celluosic resin or cyclic olefin base resin.

This is because among thermoplastic resin film, and celluosic resin and cyclic olefin base resin are specially adapted to the film of optical applications because their transparency, toughness, optical isotropy etc.

According to a twenty-first aspect of the invention, in according to described method aspect the 13 to the 20, described film has the following thickness offset of 1 μ m.

When using the preparation in accordance with the present invention preparation to be suitable for the thermoplastic resin film of optical applications, it is the following suitable flat state of 1 μ m that prepared blooming can demonstrate thickness offset.

According to any one aspect of the present invention, can be suppressed at by use and be melt into the thickness offset that embrane method prepares the film in the thermoplastic resin film, and can obtain to be suitable for the thermoplastic resin film of optical applications.

Description of drawings

Fig. 1 illustrates according to first embodiment, is used to prepare the overall schematic of an example of the equipment of thermoplastic resin film;

Fig. 2 illustrates according to first embodiment sectional view of the structure of extruder;

Fig. 3 illustrates according to first embodiment enlarged perspective of the structure between die head and the chill roll;

Fig. 4 is a side view of wherein observing the structure Fig. 3 from directions X;

Fig. 5 is a side view of wherein observing the structure Fig. 3 from the Y direction;

Fig. 6 is the amplification sectional view of shield of the near surface of the chill roll in Fig. 3;

Fig. 7 illustrates according to first embodiment, the perspective view of the temperature control device of settling at the film near surface;

Fig. 8 illustrates according to first embodiment enlarged perspective of the another kind of structure between die head and chill roll;

Fig. 9 is a side view of wherein observing the structure Fig. 8 from directions X;

Figure 10 is the perspective view that is illustrated in the temperature control device that the film near surface is settled among Fig. 8;

Figure 11 is the perspective view on the other hand that is used to describe according to the means for screening of first embodiment;

Figure 12 is a side view of wherein observing the means for screening Figure 11 from directions X;

Figure 13 is the side view that is used to describe according to the another aspect of the means for screening of first embodiment;

Figure 14 is a side view of wherein observing the means for screening Figure 13 from directions X;

Figure 15 is the perspective view that is used to describe according to the means for screening of second embodiment;

Figure 16 is a side view of wherein observing the means for screening Figure 15 from directions X;

Figure 17 is the perspective view on the other hand that is used to describe according to the means for screening of second embodiment;

Figure 18 is a side view of wherein observing the means for screening Figure 17 from directions X;

Figure 19 is the block diagram of the situation of the film longitudinal stretching that wherein will prepare in the present embodiment and cross directional stretch;

Figure 20 is the table that shows the result of the embodiment of the invention;

Figure 21 is the table that shows the result of the embodiment of the invention;

Figure 22 illustrates according to this embodiment, in the casting roller system, and the amplification sectional view of the structure between die head and chill roll; With

Figure 23 is the enlarged perspective that the conventional structure between die head and the chill roll is shown.

The specific embodiment

The preferred embodiment that is used to prepare the method for thermoplastic resin film according to of the present invention is described below with reference to the accompanying drawings.Be meant by the number range that adopts ＂ to ＂ to represent in this manual and be included in the numerical value described before and after the ＂ to ＂ respectively as the scope of lower limit and higher limit.

At first, first embodiment of the present invention will be described.The present embodiment has shown that the formation of the end on the width of film air-flow collides and the example of shielding film with the film near surface to suppress ascending air stream by shield being installed or being passed through at least.

Fig. 1 illustrates the schematic diagram of an example of preparation equipment of method that is used to prepare thermoplastic resin film that is used to implement according to first embodiment of the present invention.The present embodiment has shown an example of preparation cellulose acylate film.Yet, the invention is not restricted to cellulose acylate film, and can be used for other thermoplastic resin film such as cyclic olefin base resin film.

As shown in fig. 1, preparation equipment 10 mainly is made up of following: extruder 14, and it is used to acidylate celluosic resin 12 fusions; Die head 16, it is used for the acylated cellulose resin 12 of fusion is discharged with the form of film; Multistage many chill rolls 18,20 and 22, it is used for and will cools off at the cellulose acylate film 12A (hereinafter referred to as film 12A) that is in heat and molten condition after die head 16 is discharged; Stripper roll 24, it is used for stripping film 12A from the last chill roll 22; With up-coiler 26, the film 12A that it is used to reel and is cooled.

Fig. 2 is the sectional view that the structure of extruder 14 is shown.As shown in Figure 2, the single shaft screw rod 38 that will have a screw thread of tiing up on screw shaft 34 (flight) 36 is placed in the machine barrel 32 of extruder 14.This single shaft screw rod 38 is configured to the motor rotation by not showing.The loading hopper that does not show is installed in the supply port 40 of machine barrel 32.Acylated cellulose resin 12 is supplied in the machine barrel 32 via supply port 40 from this loading hopper.

Machine barrel 32 inside comprise successively from supply port 40 1 sides: drainage area (by the zone of (A) expression), and it is used for quantitatively carrying the acylated cellulose resin of supplying with from supply port 40; Compressional zone (by the zone of (B) expression), it is used for mediating and compression acylated cellulose resin; And metering zone (by the zone of (C) expression), it is used for the acylated cellulose resin that weighing is mediated and compressed.With in extruder 14 the acylated cellulose resin of fusion be transported to continuously the die head 16 from supply port 42.

Preferably the screw compression ratio with extruder 14 is set at 1.5 to 4.5, and preferably the ratio (L/D) of barrel length and machine barrel internal diameter is set at 20 to 70.Here, screw compression is than being represented with the volumetric ratio of metering zone (C) by drainage area (A), in other words, volume by the per unit length of drainage area (A) is represented divided by the volume of the per unit length of metering zone (C), and is calculated by the outside diameter d 1 that adopts the screw shaft 34 in the drainage area (A), the outside diameter d 2 of the screw shaft 34 in the metering zone (C), the groove diameter a1 of drainage area (A) and the groove diameter a2 of metering zone (C).Extrusion temperature is preferably 190 to 300 ℃.Because residual oxygen is oxidized, preferably when the extruder that makes extruder inside be full of inert gas (nitrogen etc.) stream or to dispose exhaust outlet by use vacuumizes extruder inside, extrude the resin of fusion in order to prevent molten resin.

To deliver in the die head 16 via pipeline 44 (referring to Fig. 1) by the acylated cellulose resin 12 of extruder 14 fusions, and the form with film is discharged from the outlet of die head.The variation of discharge pressure that preferably will be when discharging molten resin from die head 16 is controlled at below 10%.

As shown in fig. 1, three chill rolls 18,20 and 22 are placed in the downstream of die head 16 with multistage form.Chill roll 18 is configured to cool off and solidify molten resin 12A by in the middle of the touch roll 28 that molten resin 12A is clipped in itself and arranged adjacent.

Fig. 3 is the perspective view that is illustrated in the structure between die head 16 and the chill roll 18.Fig. 4 is a side view of wherein observing the structure Fig. 3 from directions X.Fig. 5 is the sectional view that shows when the structure of the center line from the thickness direction of die head 16 towards Y direction cutting drawing 3.

As shown in Figure 3, a pair of

shield

46 and 46 is placed in the space between the surface of the outlet of die head 16 and chill roll 18, with the both ends on the width that surrounds film 12A.

Each shield 46 is placed in the inboard at both ends of the chill roll 18 of the side certain intervals on the width of die head 16.Each shield 46 can directly be fixed on the side of die head 16, perhaps the support member support that can not shown and fixing.

The width W of shield 46 is configured to cover effectively the ascending air stream that the heat radiation by die head 16 causes, and for example, as shown in Figure 4, is equal to or greater than the width W d of the side of die head 16.

Preferably the outlet of die head 16 is positioned to than any one the lower position among the summit Q of the summit P of touch roll 28 and chill roll 18.Thereby, the outlet of die head 16 and the outside in the space between chill roll 18 and the touch roll 28 are covered out, therefore film 12A is discharged from die head 16, and be subjected to the influence of ascending air stream etc. hardly.

The air gap L between the surface of the outlet of die head 16 and chill roll 18 is preferably below the 200mm, so that film 12A is subjected to the outer gas stream influence of (comprising ascending air stream) hardly.

Clearance C 1 between the end on the width of end on the width of shield 46 and film 12A preferably straitly forms, make the mobile ascending air in surface that can cover chill roll 18 effectively flow, and the described clearance C 1 preferred about 50mm in end on the width of film 12A, as shown in Figure 5.Here, needn't need to provide, but be preferably formed, make and to discharge air stream in the space that crested plate 46 surrounds to for example below the 10mm in the side and the clearance C 2 between the shield 46 of die head 16.

Fig. 6 is the sectional view that is illustrated in the bottom and the space between the chill roll 18 of shield 46.As shown in Figure 6, the bottom of shield 46 has labyrinth type mechanism and flows into die head 16 sides to suppress the both ends of air from the width of chill roll 18 effectively.In the figure, shield 46 has labyrinth type mechanism, and described labyrinth type mechanism forms to such an extent that cover characteristic than shield itself is thicker with the flow resistance and the raising that increase air.Yet thickness is not limited to above-mentioned thickness, and labyrinth type mechanism can be formed and has the thickness identical with shield.Do not contact in surperficial such scope of chill roll 18 at the bottom that makes shield 46 (protuberance of the labyrinth type mechanism in Fig. 6), preferably will be set at below the 10mm in the clearance C 3 between the surface of shield 46 and chill roll 18.

When this mode is constructed shield 46, the variation of the wind speed in the space of crested plate 46 encirclements is controlled at below 0.5 meter per second, below preferred 0.3 meter per second, and more preferably below 0.1 meter per second.Preferably the absolute value with wind speed is controlled to be below 1 meter per second.

The airspeedometer that can know by use at the wind speed of the near surface of film 12A, for example by Kanomax Japan, the wind-speed indicator Anemomaster that Inc. makes (main body: MODEL6162 and probe: measurement such as MODEL204).The surface (film surface) that is defined in apart from film 12A at the wind speed of the near surface of film 12A is the measured value of the position below the 20mm.

Shield 46 preferably has good becalm characteristic and heat preservation property, and can preferably use the metallic plate of for example being made by stainless steel etc.

The main cause of ascending air stream of thickness offset of film 12A of exerting an influence is, die head 16 is hot, thereby causes between die head and the surrounding atmosphere and/or the big temperature difference between the surface temperature of die head and chill roll 18 etc.Thereby, by the atmosphere temperature of rising, therefore reduce the temperature difference between atmosphere temperature and the die head 16 at the near surface of film 12A, can be so that produce ascending air stream hardly.

Fig. 7 is the perspective view that an example of the structure with temperature control device of settling at the near surface of film 12A is shown.

As shown in Figure 7, the heater 46A (heater) that will be used for heating the space that crested plate 46 surrounds embeds shield 46, and heater 46A is connected with control device 50.At the near surface of film 12A, settle temperature sensor 48, and it is configured such that and measurement result can be outputed in the control device 50.The temperature that temperature sensor 48 is measured at the near surface of film 12A, control device 50 is controlled the heating-up temperature that is embedded into the heater 46A in the shield 46 based on measurement result then.Thereby, can will be controlled in the predetermined scope in the atmosphere of the near surface of film 12A and the temperature difference between the die head 16.

For example, preferably temperature sensor 48 being installed in from the surface of film 12A is position below the 20mm.

Heater is not limited to above-mentioned heater, and can use various heaters.In the present embodiment, heater 46A is embedded in the shield 46, but be not limited to this method, and heater can be placed in shield 46 in different position, position.

In addition, can settle the discharger (not shown) to discharge ascending air stream the space that surrounds from crested plate 46.Such discharger is not particularly limited, and can use for example suction pump, injector etc.

The touch roll method is to place the curtain coating drum to go up with the method with film surface appearance touch roll.Touch roll 28 does not preferably have the high rigidity of common level, and preferably has elasticity.Therefore, touch roll 28 can be controlled at scope of the present invention or littler with surface heterogeneity by its excessive applanation.In order to accomplish this point, the THICKNESS CONTROL of urceolus must be become thinner than common roller.The thickness of urceolus (Z) is preferably 0.05mm to 7.0mm, 0.2mm to 5.0mm more preferably, and be preferably 0.3mm to 3.5mm.Touch roll can be the roller that is positioned on the metal shaft, and heat medium (fluid) can flow between touch roll and metal shaft.Perhaps, touch roll can be wherein to settle elastomer layer on urceolus and metal shaft, and the space between urceolus and elastomer layer is full of the roller of heat medium (fluid).

The temperature of touch roll preferably is set at 60 ℃ to 160 ℃, more preferably is set at 70 ℃ to 150 ℃, and preferably is set at 80 ℃ to 140 ℃.This temperature control can realize by the inside of roller by making controlled liquid of its temperature or gas.By this way, roller preferably has the temperature control device that is positioned in wherein.

The material of touch roll is preferably metal, and stainless steel more preferably.The touch roll that also preferably has coating surface.On the other hand, preferred rubber roller or use rubber lined metallic roll not, reason is that the inhomogeneities of rubber surface is too big and can not form the thermoplastic resin film with above-mentioned surface heterogeneity.

The surface of touch roll and casting roller has below the 100nm, below the preferred 50nm, and the more preferably following arithmetic average height Ra of 25nm.

For by using the temperature conditions of many chill rolls with multistage form cooling resin, the upstream side that preferably temperature on roller surface is set at from the throughput direction of film reduces successively.

Then, will the operation that be used to prepare the equipment of thermoplastic resin film according to of the present invention be described with reference to figure 3 and Fig. 5.

As shown in Figure 3, the film 12A that discharges from die head 16 lands on the surface of chill roll 18, is cooled when being clipped between chill roll 18 and the touch roll 28 then and solidifies.

At this moment, as shown in Figure 5, the both ends from the width of chill roll 18 are covered by a pair of shield 46 to the mobile ascending air stream (dotted arrow) of the outlet of die head 16.Therefore, shield can prevent from the ascending air stream that the surface of chill roll 18 flows to die head 16 flow into film 12A around.Therefore, will change being controlled at below 0.3 meter per second, make the thickness offset that can prevent film 12A at the wind speed of the near surface of film 12A.

And when being placed in temperature control device in the shield as shown in Figure 7, temperature control device is adjusted to the near surface of film 12A and the temperature difference T between the die head 16 below 160 ℃.Particularly, when the temperature of die head 16 was about 240 ℃, temperature control device will be controlled at more than 80 ℃ at the atmosphere temperature of the near surface of film 12A.Therefore, can be reduced in die head 16 and on every side between the temperature difference, thereby can be so that produce ascending air stream hardly.

As mentioned above, can prevent to form in the operation, flow into from the ascending air stream on the surface of chill roll 18 in the air gap between the surface of die head 16 and chill roll 18 in the fused film that is used to form film 12A according to the preparation equipment of the present embodiment.Therefore, this preparation equipment prevents that wind speed from owing to the ascending air stream at the near surface of film 12A changes, therefore can prevent to produce thickness offset in film 12A.Therefore, this preparation equipment can prepare the cellulose acylate film that has good flat shape and be suitable for optical applications.

The present embodiment has shown the wherein weak point of the air gap between die head 16 and chill roll 18 and the only example of the arrangement of the two sides on the width of die head 16 shield 46, but when the air gap is long, the preferable configuration masking device, described masking device has the shield 46 that also is positioned in relative such position with the surface of film 12A, and surrounds the entire circumference of film 12A.Therefore, masking device not only can cover the ascending air stream that the both ends from the width of chill roll 18 flow into, and can prevent to flow to via the near surface of film 12A the ascending air stream of die head 16 and the ascending air stream that flows to die head 16 from the surface of touch roll 28 via the near surface of film 12A from the surface of chill roll 18.

In this case, preferably will be positioned to from the surface of film 12A with the surperficial relative shield 46 of film 12A be below the 200mm.

In the present embodiment, described the example that uses contact roll shape chill roll 18, but chill roll 18 is not limited to the above-mentioned type.Chill roll 18 for example can adopt curtain coating roll shape as shown in Figure 8.

Fig. 8 illustrates in the casting roller system, comprises the enlarged perspective of the structure in the space between die head and the chill roll.Fig. 9 is a side view of wherein observing the structure Fig. 8 from directions X.Figure 10 is the perspective view that wherein temperature control device is placed in the situation in the shield of Fig. 8.In described figure, represent by identical reference marker with member identical in Fig. 4, and with detailed.

As shown in Figure 8, shield 46 not only is positioned in the space between die head 16 and the chill roll 18, the both ends on the width of film 12A, and be positioned in chill roll 18 tops to surround the surface of film 12A.

In this case, preferably will be positioned to slightly further more outstanding with the shield 46 (shield in the left side in Fig. 9) of the surperficial relative arrangement of film 12A than the surface of chill roll 18.That is, in the example shown in Fig. 9, shield 46 is positioned at the more left side of (Far Left point) around the left side of chill roll 18.

In addition, as shown in Figure 10, when temperature control device being placed in the shield 46, the atmosphere temperature in the space that crested plate 46 can be surrounded is controlled to predetermined temperature.Therefore, shield 46 can reduce the difference between the temperature of atmosphere temperature and die head 16, therefore can prevent to form ascending air stream.Temperature control device has the structure identical with the said structure shown in Fig. 7.

In the embodiment shown in Fig. 8, described the wherein structure on the two sides (entire circumference) of shield encirclement film 12A, but this structure is not limited to said structure.For example, shield can be configured to only to be enclosed in the face of the side of film 12A.Especially preferably make shield cover the face that among the surface of film 12A, does not contact chill roll 18 1 sides.Therefore, shield can cover ascending air stream effectively, therefore can be suppressed among the film 12A and produce thickness offset.

In above-mentioned, described the preferred embodiment that is used to prepare the method for thermoplastic resin film according to of the present invention, but the invention is not restricted to described embodiment, and can adopt various aspects.

For example, in the present embodiment, effectively apply the present invention to particularly have the dependent molten resin of high-temperature of viscosity.Having high temperature dependent molten resin specifically comprises: the temperature of the molten resin of the film 12A after will be just from die head 16, discharging be defined as T (℃) time, this resin (T-10) to T (℃) temperature range in, have the thermoplastic resin of counting the viscosity gradient of the film more than 1.7Pas/ ℃ with absolute value.When using such resin, preparation equipment can change and the remarkable variations in temperature (temperature fluctuation) that reduces the film 12A that is in molten condition by controlled wind speed, that is, and and viscosity change (viscosity fluctuation), and can significantly improve thickness offset.

Can measure the viscosity of molten resin by using the viscoelasticity measurement equipment (for example Modular Compact Rheometer:Physica MCR301 of Anton PaarGmbH manufacturing) that for example uses cone-plate.Can reach below 0.1% until water content at abundant drying thermoplastic resin, measuring under the measuring condition of shear rate with the form of 1 (/ second) under the predetermined temperature (near the temperature of molten resin temperature), measure the viscosity of molten resin then.

In the present embodiment, use by adopting the example that shield 46 covers ascending air stream to be described, still the invention is not restricted to shield.For example, can cover ascending air stream by forming air-flow.

Figure 11 is the figure that is used to describe according to another aspect of means for screening of the present invention.Figure 12 is a side view of wherein observing the means for screening of Figure 11 from directions X.

As shown in Figure 11, means for screening 51 has shell 52, space between the surface of described shell 52 encirclements die head 16 in the vertical and the surface of chill roll 18, and will be used for being connected to both ends on the width of shell 52, with the end on the width of shielding film 12A at the wind pushing nozzle 54 that forms air-flow on the Y direction.

Wind pushing nozzle 54 is connected on the pressure fan that does not show, and is configured to blow clean air.Wind pushing nozzle 54 also disposes not temperature displayed controlling organization, and described temperature control device can be controlled wind pushing temperature.

The shell 52 that is connected with wind pushing nozzle 54 has labyrinth type mechanism 56, and described labyrinth type mechanism 56 is made by a plurality of baffle plate 52A that the both ends on the width of shell form.Therefore, the air that supplies to shell 52 from wind pushing nozzle 54 is cushioned by labyrinth type mechanism 56 time, simultaneously by rectification, forms air-flow on the Y direction then with the end on the width of shielding film 12A.The air of supplying with like this from wind pushing nozzle 54 is cushioned by labyrinth type mechanism 56 time, does not therefore disturb the air stream at the near surface of film 12A.

Preferably the flow velocity with the air of the end on the width of shielding film 12A is set in 0.6 to 1.0 meter per second.Preferably wind pushing temperature is set in about Tg ± 20 ℃ (for example about 140 ℃), reason is when wind pushing temperature is too high, and film 12A causes constriction (neck-in) easily.

Space between the end on the width of film 12A and the air-flow of formation is preferably in the scope more than 50mm.

In the embodiment in Figure 11, use and adopt wind pushing nozzle 54 to be described as the example that air-flow forms device.Yet air-flow forms device and is not limited to wind pushing nozzle, and can form air-flow with the end on the width of shielding film 12A, as shown in Figure 13 by suction nozzle 58.

Figure 13 is the perspective view that is used to describe according to the another aspect of means for screening of the present invention.Figure 14 is a side view of wherein observing the means for screening Figure 13 from directions X.

As shown in Figure 13, with Figure 11 in much at one mode construct means for screening, difference is to settle suction nozzle 58 to replace wind pushing nozzles 54.In the figure, have with Figure 11 and Figure 12 in the member of identical function represent by identical reference marker, and with detailed.

Therefore, means for screening makes the end on the width of suction nozzle 58 suction film 12A, thereby the air-flow that can form mitigation is with the end on the width of shielding film 12A.Therefore, means for screening makes air-flow not disturb air stream at the near surface of film 12A, and can prevent that ascending air stream from flowing into from the both ends on the width of film 12A.

Then, second embodiment of the present invention will be described.The present embodiment has shown the example that changes by the wind speed of settling the air fairing that will carry out rectification at the air-flow of the near surface of film to be reduced in the film near surface.

Figure 15 is the perspective view that is used to describe according to another aspect of the equipment that disposes wind pushing nozzle 60 (air-flow formation device) that is used to prepare thermoplastic resin film of the present invention.Figure 16 is a side view of wherein observing the preparation equipment of Figure 15 from directions X.In described figure, have with above-mentioned first embodiment in the member of identical function represent by identical reference marker, and with detailed.

As shown in Figure 15, with the outlet that vertically be placed in die head 16 of a pair of wind pushing nozzle 60 along die head 16.

Wind pushing nozzle 60 is connected to not on the pump that shows etc., and goes up and carry clean air equably along the surface of film 20A discharging direction (direction downward vertically).Therefore, as shown in Figure 16, even when the near surface of film 20A has produced ascending air stream, wind pushing nozzle 60 has also been offset ascending air stream by the clean air that flows on the direction opposite with ascending air stream, thereby the wind speed that can be reduced in the near surface of film 12A changes.

Preferably the flow velocity of the air that will carry from wind pushing nozzle 60 is set in the cancellation ascending air and flows necessary speed, is specially 0.6 to 1.0 meter per second.In the foregoing description, the flow velocity of air is defined as for example and is being the value of the position below the 20mm from the film surface of film 12A.When wind pushing temperature was too high, film 12A caused constriction easily, so preferably wind pushing temperature is set in about Tg ± 20 ℃ (for example 140 ℃).

The air fairing is not limited to wind pushing nozzle 60, and can for example be suction nozzle 62 as shown in Figure 17.

Figure 17 is the perspective view that is used to describe according to another aspect of the equipment that disposes suction nozzle 62 (air fairing) that is used to prepare thermoplastic resin film of the present invention.Figure 18 is a side view of wherein observing the preparation equipment Figure 17 from directions X.

As shown in Figure 17, with the outlet that vertically be placed in die head 16 of a pair of suction nozzle 62 along die head 16.Therefore, the near surface at film 12A is formed on and the square downward vertically stream of going up in the opposite direction.Therefore, 62 pairs of air at the near surface of film 12A of suction nozzle carry out rectification, therefore can reduce wind speed and change.

Preferably will be set in the necessary value of turbulent flow that rectification is caused by ascending air stream at the flow velocity of the air-flow of the near surface formation of film 12A, and can be set in for example 0.6 to 1.0 meter per second by vacuum draw.

In above-mentioned Figure 15 to 18, shown wherein near the example that wind pushing nozzle 60 or suction nozzle 62 is placed in the outlet of die head 16.Yet, the position be not limited to die head 16 outlet near, and can settle in the lower end of film 12A (chill roll side).

As shown in Figure 19, preferably will stretch on vertical and horizontal by the film formed thermoplastic film 12A of fusion in the above described manner, and can make up with shrink process.In above-mentioned operation, preferred operation is the longitudinal stretching film, the operation of cross directional stretch film then, or with the cross directional stretch and the vertical operation of shrink process combination.Preceding a kind of operation is suitable for producing high Rth, and then a kind of operation is suitable for producing low Rth.

When using cross directional stretch and vertically the combination step of shrink process is handled film, vertically shrink process can be carried out in the cross directional stretch step process, can carry out after the cross directional stretch step, perhaps can all carry out after the neutralization of cross directional stretch step process.And, before the cross directional stretch step or afterwards, perhaps before the cross directional stretch step and afterwards can be with longitudinal stretching step and the combination of cross directional stretch step.In addition, film can prepare through the following steps: form step by fused film and prepare film 12A; Under situation without up-coiler 26 temporary transient coiling films, continuously elongated film on vertical and horizontal; The film of reeling then.

In the present invention, can make up stretched film in the vertical or with the cross directional stretch step separately.Film can carry out longitudinal stretching before or after the cross directional stretch step, but preferably stretched before the cross directional stretch step.Can with film one-level or separate multistage in longitudinal stretching.

By settling two pairs of nip rolls, and be controlled at the peripheral speed of the nip rolls of outlet side, make it be higher than peripheral speed, heat the space between the nip rolls of both sides simultaneously, can realize the longitudinal stretching operation at the nip rolls of entrance side.At this moment, by the width (W) of length (L) between the change nip rolls and the film before stretching, can change the producing method of the delay on thickness direction.Rth can be by being controlled to be L/W greater than 2, and reduce in (long span stretching) below 50, and can be by L/W is controlled to be more than 0.01, and increase (short span stretches) below 0.3.In the present invention, can use any method among long span stretching, short span stretching and zone line stretch (stretching=L/W is greater than 0.3 and below 2 wherein), but, preferably use long span to stretch or short span stretching because orientation angles is diminished.And, preferably when being intended to give high Rth, adopting short span to stretch, and the mode that when be intended to give low Rth, adopts long span to stretch use drawing process when distinguishing drawing process.

Preferred draft temperature in the longitudinal stretching operation is preferably (Tg-10 ℃) to (Tg+50) ℃, and more preferably (Tg-5 ℃) to (Tg+40) ℃, and most preferably be (Tg) to (Tg+30) ℃.Preferred stretching enlargement ratio is 2% to 200%, more preferably more than 4%, and below 150%, and most preferably be 6% to 100%.

Film can carry out cross directional stretch by using stenter.Particularly, stenter is with the fixing both ends on the width of film of clip, and with film in the horizontal expanding so that film is stretched.At this moment, can control draft temperature in the stenter by temperature required air is transported to.Draft temperature is preferably more than Tg-10 ℃ and below Tg+60 ℃, and more preferably more than Tg-5 ℃ and below Tg+45 ℃, and it is above and below Tg+30 ℃ most preferably to be Tg.Preferred stretching enlargement ratio is more than 10% and below 250%, more preferably more than 20% and below 200%, and most preferably is more than 30% and below 150%.Stretching enlargement ratio described here is defined by following expression formula.

Stretching enlargement ratio (%)=100 * { (in the length after the stretching)-(length before stretching) }/(length before stretching)

Will be described below various materials used among the present invention now.

[material of thermoplastic film]

The thermoplastic film of Shi Yonging is not particularly limited in the present invention, but preferably comprises acylated cellulose base resin, contains the polymer of lactonic ring, cyclic olefin base resin and Merlon.Among them; preferable material is acylated cellulose base resin and cyclic olefin base resin; preferred material is the acylated cellulose that contains acetate group and propionic ester group among them; and the cyclic olefin base resin that obtains by addition polymerization, and most preferred material is the cyclic olefin base resin that obtains by addition polymerization.

(1) acylated cellulose base resin

Available acylated cellulose base resin is the acylated cellulose base resin of describing in following document for example: Japanese Patent Application Publication 2006-45500; Japanese Patent Application Publication 2006-241433; Japanese Patent Application Publication 2007-138141; Japanese Patent Application Publication 2001-188128, Japanese Patent Application Publication 2006-142800 and Japanese Patent Application Publication 2007-98917.Total substitution value of acyl group is preferably more than 2.1 and below 3.0.The substitution value of acetyl group is preferably more than 0.05 and below 2.5, and more preferably more than 0.05 and below 0.5, perhaps is more than 1.5 and below 2.5.The substitution value of propiono is preferably more than 0.1 and below 2.8, and more preferably more than 0.1 and below 1.2, perhaps is more than 2.3 and below 2.8.

(2) cyclic olefin base resin

Cyclic olefin base resin preferably forms by polymerization ENB based compound.This polymerisation can be any in ring-opening polymerization and the polyaddition reaction.The compound that obtains by polyaddition reaction has been described: Japan Patent 3517471 in following document for example, Japan Patent 3559360, Japan Patent 3867178, Japan Patent 3871721, Japan Patent 3907908, Japan Patent 3945598, the Japanese national of international patent application is announced 2005-527696, Japanese Patent Application Publication 2006-28933 and WO 2006/004376.Particularly preferred compound is the compound of describing in Japan Patent 3517471.

For example in the following document compound that obtains by ring-opening polymerization: WO1998/14499 is being described, Japan Patent 3060532, Japan Patent 3220478, Japan Patent 3273046, Japan Patent 3404027, Japan Patent 3428176, Japan Patent 3687231, Japan Patent 3873934 and Japan Patent 3912159.Among them, the preferred compound that obtains by ring-opening polymerization is the compound of describing in WO 1998/14499 and Japan Patent 3060532.Among described compound, the more preferably cyclic olefin resin that obtains by addition polymerization.

(3) contain the polymer of lactonic ring

This polymer is the polymer that has by the lactonic ring structure of general formula (1) expression:

[formula 1]

(R wherein ¹, R ²And R ³Represent hydrogen atom or the carbon number organic residue in 1 to 20 scope independently of one another, wherein this organic residue can contain oxygen atom).The compound of general formula (1) contains proportional 5 to the 90 weight % that are preferably, 10 to 70 weight % more preferably, and most preferably be the lactonic ring structure of 10 to 50 weight %.

Constitutional unit (constitutional repeating unit) preferably is different from the lactonic ring structure by general formula (1) expression, and is selected from (methyl) acrylate, carboxylic monomer, unsaturated carboxylic acid and is made of at least a compound in the monomer of following general formula (2a) expression by polymerization:

[formula 2a]

(R wherein ⁴Expression hydrogen atom or methyl; X represent alkyl in 1 to 20 scope of hydrogen atom or carbon number separately, aryl ,-the OAc group ,-the CN group ,-CO-R ⁵Group or-C-O-R ⁶Group; The Ac group is represented acetyl group; And R ⁵And R ⁶Expression hydrogen atom or the organic residue of carbon number in 1 to 20 scope).

For example, the polymer that contains lactonic ring can adopt the compound of describing in the following document: WO2006/025445, Japanese Patent Application Publication 2007-70607, Japanese Patent Application Publication 2007-63541, Japanese Patent Application Publication 2006-171464 and Japanese Patent Application Publication 2005-162835.

(4) polycarbonate-base resin

This polycarbonate-base resin is the resin that dihydroxy component and carbonate precursor reaction is obtained by interfacial polymerization method or melt polymerization method, and can preferably adopt at Japanese Patent Application Publication 2006-277914 the polycarbonate-base resin of describing among Japanese Patent Application Publication 2006-106386 and the Japanese Patent Application Publication 2006-284703.

(5) additive

These thermoplastic films can amount be that the plasticizer of the sweet acid alkyl ester of alkyl phthalic acyl group, phosphate, carboxylate and polyalcohol of 0 to 20 quality % is as additive.The stabilizing agent that can be 0 to 3 quality % with amount joins in the thermoplastic resin, described stabilizing agent comprises: phosphite ester-based stabilizer (for example, three (4-methoxyl group-3,5-diphenyl) phosphite ester, three (nonyl phenyl) phosphite ester and three (2,4-two-tert-butyl-phenyl) phosphite ester); Phenol-based stabilizer (for example, 2,6-two-tert-butyl group-4-methylphenol, 2, the 2-methylene-bis(4-ethyl-6-t-butyl phenol), 2,5-two-TBHQ, [3-(3 for pentaerythrite base four, 5-two-tert-butyl-hydroxy phenyl) propionic ester, 4,4-sulfo--two-(the 6-tert-butyl group-3-methylphenol), 1,1-bis(4-hydroxyphenyl)cyclohexane, and octadecyl-3-(3,5-two-tert-butyl-hydroxy phenyl) propionic ester]; Epoxide; And sulfide compound.Can be 0 to 1 with concentration, the delustering agent of 000ppm joins in the thermoplastic resin, and described delustering agent comprises: the inorganic particles of silica, titanium dioxide, zirconia, aluminium oxide, calcium carbonate, clay etc.; With crosslinked polyacrylic (acryl), the organic fine particles of crosslinked styrene etc.Also preferably with the UV absorbent (for example, 2, the 4-dihydroxy benaophenonel, 2-hydroxyl-4-methoxy benzophenone and 2, [4-(1,1 for the 2-di-2-ethylhexylphosphine oxide, 3,3-tetramethyl butyl)-6-[(2H-BTA-2-yl) phenol]]), infrared absorbent and delay conditioning agent join in the thermoplastic resin.

[embodiment]

Referring now to embodiment feature of the present invention is described more specifically, but the restricted explanation of the specific embodiment that scope of the present invention should not be described below.

(embodiment 1)

In the present embodiment, how many surface state of test membrane 12A improved, and described film 12A forms by the fused film at Fig. 3 and uses the air gap (molten resin film) that shield 46 covers between die head 16 and the contact roll shape chill roll 18 to prepare in the operation.

It is that 80 μ m and the width behind cutting tip are the shape of 1500mm that film 12A is finally formed film thickness.Use cyclic olefine copolymer (hereinafter referred to as ＂ COC ＂) as raw material.The glass transition temperature Tg of cyclic olefine copolymer is 140 ℃.

The air gap between the surface of the outlet of die head 16 and chill roll 18 is set at 100mm.The temperature of die head 16 is set at 260 ℃, and linear velocity is set at 20 meter per seconds.

As shield 46, use by the SUS304 material and make and thickness is the metallic plate of 5mm.Only shield 46 is placed in the both ends (side) on the width of film 12A.Shield 46 is installed is made that in the clearance C between the side of shield 46 and die head 16 2 be 5mm (clearance C 1 between the end on the width of shield 46 and film 12A is 50mm), and the clearance C between the surface of shield 46 and chill roll 18 3 is 12mm.Using the temperature control device shown in Fig. 7, will be that the atmosphere temperature of the position of 20mm is adjusted to 80 ℃ on the surface from film 12A, and measure wind speed and wind-warm syndrome in this position.

(method of measuring wind and wind-warm syndrome)

Use is by Kanomax Japan, wind-speed indicator Anemomaster (main body: MODEL6162, and probe: MODEL0204) that Inc. makes.

On the surface from film 12A is 20mm, five points on the width of film 12A, measuring wind variation separately, wind speed absolute value and wind-warm syndrome in time.

In addition, the surface temperature control with

chill roll

18,20 and 22 is 130 ℃.Measure the thickness offset of prepared film.

(measuring the method for thickness)

By using the continuous thickness indicator of off-line contact-type (the film thickness determination device KG601B that makes by Anritsu Corporation), and be set at 1mm and measure thickness by measuring spacing.Thickness on the width of measuring film on the whole width of the film 12A after the finishing, and the thickness on the throughput direction of measuring film on the length of the 3m of film 12A.According to following standard evaluation thickness offset.

Excellent ... that the scope of thickness offset is below the 1 μ m

Well ... the scope of thickness offset is below the 2 μ m

Generally ... the scope of thickness offset is below the 5 μ m

Difference ... the scope of thickness offset surpasses 1 μ m

This results are shown among Figure 20.

(embodiment 2)

With with embodiment 1 in the similar method of method prepare film, difference is to settle shield 46 to make that the clearance C 3 between the surface of shield 46 and chill roll 18 can be 5mm.This results are shown among Figure 20.

(embodiment 3)

With with embodiment 2 in the similar method of method prepare film, difference is shield 46 is configured to not only to surround both ends on the width of film 12A, and comprises the entire circumference of film 12A on the surface of film 12A.This results are shown among Figure 20.

(embodiment 4)

With with embodiment 3 in the similar method of method prepare film, difference is the air gap between die head 16 and the chill roll 18 (length of molten resin film) is set at 200mm.This results are shown among Figure 20.

(embodiment 5)

With with embodiment 3 in the similar method of method prepare film, difference is the air gap between die head 16 and the chill roll 18 (length of molten resin film) is set at 50mm.This results are shown among Figure 20.

(embodiment 6)

With with embodiment 1 in the similar method of method prepare film, difference is to use curtain coating roll shape chill roll 18 as shown in Figure 22 to replace contact roll shape chill rolls 18.In above-mentioned situation, shield 46 is placed in the side 46A shown in Figure 22, side 46B, positive 46C (a not side that contacts with chill roll 18) and bottom surface 46E.This results are shown among Figure 20.

(embodiment 7)

With with embodiment 6 in the similar method of method prepare film, difference is the entire circumference (side 46A, side 46B, positive 46C, positive 46D and bottom surface 46E) that shield 46 is configured to surround the surface that comprises film 12A, and clearance C 3 is changed into 5mm.This results are shown among Figure 20.

(embodiment 8)

With with embodiment 1 in the similar method of method prepare film, difference is the kind of resin is changed into propionic acid acylated cellulose (hereinafter referred to as ＂ CAP ＂) from cyclic olefine copolymer.The glass transition temperature Tg of propionic acid acylated cellulose is 135 ℃.This results are shown among Figure 20.

(embodiment 9)

With with embodiment 8 in the similar method of method prepare film, difference is shield 46 is configured to not only to surround both ends on the width of film 12A, and comprises the entire circumference on the surface of film 12A, and clearance C 3 is changed into 5mm.This results are shown among Figure 20.

(embodiment 10)

With with embodiment 1 in the similar method of method prepare film, difference is the kind of resin is changed into PETG (hereinafter referred to as ＂ PET ＂) from cyclic olefine copolymer, and will be that the atmosphere temperature of the position of 20mm is arranged on 90 ℃ on the surface from film 12A.PETG has 70 ℃ glass transition temperature Tg.This results are shown among Figure 20.

(embodiment 11)

With with embodiment 10 in the similar method of method prepare film, difference is shield 46 is configured to not only to surround both ends on the width of film 12A, and comprises the entire circumference on the surface of film 12A, and clearance C 3 is changed into 5mm.This results are shown among Figure 20.

(comparative example 1)

With with embodiment 1 in the similar method of method prepare film, difference is not settle shield 46.This results are shown among Figure 20.

(comparative example 2)

With with embodiment 6 in the similar method of method prepare film, difference is not settle shield 46.This results are shown among Figure 20.

(comparative example 3)

With with embodiment 8 in the similar method of method prepare film, difference is not settle shield 46.This results are shown among Figure 20.

(comparative example 4)

With with embodiment 10 in the similar method of method prepare film, difference is not settle shield 46.This results are shown among Figure 20.

Such as from the table of Figure 20 understanding, the wind speed that any setting that wherein shield 46 is placed in the embodiment 1 to 11 between the surface of die head 16 and chill roll 18 shows at the near surface of film 12A is changed to below 0.5 meter per second, and shows the abundant result with little thickness offset.In addition, any equipment list of the foregoing description 1 to 11 reveals the wind speed absolute value that is low to moderate 1 meter per second, and does not show the identifiable adverse effect to thickness offset.

In contrast, wherein between the surface of die head 16 and chill roll 18, do not settle any equipment list of the comparative example 1 to 4 of shield 46 to reveal wind speed at the near surface of film 12A and change and surpass 0.5 meter per second, and confirmed that this variation causes thickness offset greatly.Described comparative example also demonstrates the big or bigger like this wind speed absolute value of 1.2 meter per seconds.

In addition, confirmed: surface by being reduced in chill roll 18 and the clearance C 3 between the shield 46, therefore improved the screening performance of shield, the wind speed that has reduced at the near surface of film 12A changes (

embodiment

1 and 2).Also confirmed: by shield 46 being installed, with the screening performance that improves shield 46 and will change at the wind speed of the near surface of film 12A and be reduced to below 0.1 meter per second, significantly reduced thickness offset (embodiment 3) in the entire circumference of film 12A.And, also confirmed: shorten the air gap, thereby the screening performance that improves film 12A also is effective for reducing wind speed variation (embodiment 3,4 and 5).

Confirmed: in the casting roller system and in the touch roll system, by the side in the front (positive 46C), side and the bottom surface that shield 46 are installed at least film 12A, and preferably shield 46 is installed on whole, reduced wind speed variation, and can reduce thickness offset (embodiment 6 and 7) at the near surface of film 12A.

In addition, confirmed: when using propionic acid acylated cellulose or PETG as resin, shown with cyclic olefine copolymer in identical trend (embodiment 8 to 11).

Confirmed from The above results:, can reduce the thickness offset of film by applying the present invention to prepare the equipment of thermoplastic resin film.

Then, the upcheck effect of the situation that the wind speed that uses jet system to reduce the near surface of film 12A changes.

(embodiment 12)

With with embodiment 1 in the similar method of the method wind speed of measuring the near surface of film 12A change and the thickness offset of film 12A, difference is to pass through air by the wind pushing nozzle shown in Figure 15 60 along the surface of film 12A.This results are shown in the table of Figure 21.

(embodiment 13)

With with embodiment 1 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is to pass through air by the suction nozzle shown in Figure 17 62 along the surface of film 12A.This results are shown in the table of Figure 21.

(embodiment 14)

With with embodiment 1 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is by being positioned in the wind pushing nozzle 54 in the shell, the outside at the both ends on the width of film 12A forms air-flow, and described shell is made by removing the labyrinth from the shell shown in Figure 11 52.This results are shown in the table of Figure 21.

(embodiment 15)

With with embodiment 1 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is by being positioned in the suction nozzle 58 in the shell, the outside at the both ends on the width of film 12A forms air-flow, and described shell is made by removing the labyrinth from the shell shown in Figure 13 52.This results are shown in the table of Figure 21.

(embodiment 16)

With with embodiment 1 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is that the outside at the both ends on the width of film 12A forms air-flow by being positioned in the wind pushing nozzle 54 in the shell shown in Figure 11 52 (having the labyrinth).This results are shown in the table of Figure 21.

(embodiment 17)

With with embodiment 1 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is that the outside at the both ends on the width of film 12A forms air-flow by being positioned in the suction nozzle 58 in the shell shown in Figure 13 52 (having the labyrinth).This results are shown in the table of Figure 21.

(embodiment 18)

With with embodiment 17 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is the air gap between die head 16 and chill roll 18 (length of molten resin film) is set at 200mm.This results are shown in the table of Figure 21.

(embodiment 19)

With with embodiment 17 in the similar method of the method wind speed of measuring the near surface of film 12A change, difference is the kind of resin is changed into propionic acid acylated cellulose (hereinafter referred to as ＂ CAP ＂) from cyclic olefine copolymer.This results are shown in the table of Figure 21.

Such as from the table of Figure 21 understanding, each among the embodiment 12 and 13 has shown the situation of by air the air along the surface of film 12A being carried out rectification by along described surface.Among the embodiment 14 to 19 each has shown that the outside by the both ends on the width of film 12A forms air-flow, prevents the near surface case of collision of ascending air stream and film 12A.In the comparative example 1 and 3 each has shown the situation of not controlling air-flow in so as mentioned above mode.

The wind speed that any equipment list of embodiment 12 to 19 reveals at the near surface of film 12A is changed to below 0.5 meter per second, and its thickness offset can be controlled to below the 5 μ m.

In contrast, the wind speed that any equipment list of comparative example 1 to 3 reveals at the near surface of film 12A changes above 0.5 meter per second, and has confirmed that this variation causes thickness offset greatly.

The wind speed that the equipment list of the embodiment 14 to 19 that shell 52 is used with wind pushing nozzle 54 or suction nozzle 58 reveals at the near surface of film 12A is changed to below 0.3 meter per second, and their thickness offset is diminished.And, when adopting, equipment passes through air-flow via the labyrinth type mechanism 56 in the shell 52, when the outside at the both ends on the width of film 12A formed the means for screening of air-flow then, this equipment can cover ascending air stream (embodiment 16 to 19) effectively under the situation of the wind speed of the near surface that does not disturb film 12A.

Confirmed from The above results,, can reduce the thickness offset of film by applying the present invention to prepare the equipment of thermoplastic resin film.

Claims

1. equipment that is used to prepare thermoplastic resin film, it comprises:

Die head, described die head is discharged the molten thermoplastic resin with the form of film;

Chill roll, described chill roll are positioned to relative with the outlet of described die head, and the film of discharging is cooled off and solidifies; With

Masking device, described masking device is between the end on the width of end on the width of described chill roll and described film, described film after the described outlet of described die head is discharged to landing before on the surface of described chill roll, cover the described end on the width of described film at least.

2. the equipment that is used to prepare thermoplastic resin film according to claim 1, wherein

Described masking device is a shield, described shield with the direction of the surperficial approximate vertical of described film on, be positioned between the described end on the width of described end on the width of described chill roll and described film.

3. the equipment that is used to prepare thermoplastic resin film according to claim 2, wherein

Distance between the described end on the width of described shield and described film is below the 50mm.

4. according to each described equipment that is used to prepare thermoplastic resin film in claim 2 and 3, wherein

Described masking device be positioned to the described film of further encirclement the surface around.

5. the equipment that is used to prepare thermoplastic resin film according to claim 1, wherein

Described masking device comprises:

Shell, described shell surround described die head in the vertical the surface and the space between the surface of described chill roll, and have the labyrinth type mechanism that forms therein; With

Air-flow forms device, and described air-flow forms the air-flow of device on the direction of the surperficial approximate vertical of formation of the both ends on the width of described shell and described film.

6. the equipment that is used to prepare thermoplastic resin film according to claim 5, wherein

It is wind pushing nozzle or suction nozzle that described air-flow forms device.

7. equipment that is used to prepare thermoplastic resin film, it comprises:

The air fairing, described air fairing is positioned near the described outlet of described die head, and described film after the described outlet of described die head is discharged to landing before on the surface of described chill roll, the air of the near surface of described film is carried out rectification.

8. the equipment that is used to prepare thermoplastic resin film according to claim 7, wherein

Described air fairing is positioned near the described outlet of described die head, and is to carry abreast with the discharge direction of described film or the wind pushing nozzle or the suction nozzle of suction air.

9. according to each described equipment that is used to prepare thermoplastic resin film in the claim 1 to 8, it also comprises:

Measurement mechanism, described measurement mechanism is measured the temperature at the near surface of described film; With

Heater, described heater is heated to predetermined temperature based on measurement result with the near surface of described film.

10. according to each described equipment that is used to prepare thermoplastic resin film in the claim 1 to 9, wherein

The air gap that lands between the lip-deep point of described chill roll at the described outlet and the described film of described die head is below the 200mm.

11. according to each described equipment that is used to prepare thermoplastic resin film in the claim 1 to 10, it also comprises:

Touch roll, described touch roll are positioned to adjacent with described chill roll, wherein

The described outlet of described die head is positioned in than any one the lower position in the summit of the summit of described chill roll and described touch roll.

12. a method that is used to prepare thermoplastic resin film, described method comprises the following steps:

Use is according to each described equipment that is used to prepare thermoplastic resin film in the claim 1 to 11, and the wind speed that reduces the near surface of described film changes.

13. a method that is used to prepare thermoplastic resin film, described method comprises the following steps:

Molten thermoplastic resin's form with film from die head is discharged;

The film of discharging is cooled off on chill roll and solidifies; With

The wind speed of the near surface of the film of discharging changed be controlled to be below 0.5 meter per second.

14. the method that is used to prepare thermoplastic resin film according to claim 13, described method also comprises the following steps:

After discharging, described film to landing before on the surface of described chill roll, the air of the near surface of described film is carried out rectification from described die head.

15. the method that is used to prepare thermoplastic resin film according to claim 14, wherein

By carrying abreast with the discharge direction of described film or suction air carries out the air rectification.

16. according to each described method that is used to prepare thermoplastic resin film in the claim 13 to 15, described method also comprises the following steps:

The wind speed of the near surface of described film is controlled to be below 1 meter per second.

17. according to each described method that is used to prepare thermoplastic resin film in the claim 13 to 16, described method also comprises the following steps:

The near surface of described film and the temperature difference between the described die head are controlled to be below 160 ℃.

18. according to each described method that is used to prepare thermoplastic resin film in the claim 13 to 17, wherein

Described chill roll is the contact roll shape.

19. according to each described method that is used to prepare thermoplastic resin film in the claim 13 to 18, wherein

The temperature of the molten resin after will be just from described die head, discharging be defined as T (℃) time, more than (T-10) ℃ and in the temperature range below T ℃, described thermoplastic resin has with absolute value counts viscosity gradient more than 1.7Pas/ ℃ at described thermoplastic resin.

20. according to each described method that is used to prepare thermoplastic resin film in the claim 13 to 19, wherein

Described thermoplastic resin is celluosic resin or cyclic olefin base resin.

21. according to each described method that is used to prepare thermoplastic resin film in the claim 13 to 20, wherein

Described film has the following thickness offset of 1 μ m.