JPH1120003A - Method and apparatus for manufacturing thermoplastic resin sheet - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To efficiently produce a sheet without cooling the quality of a sheet by rotating a cooling rotator for cooling and solidifying a thermoplastic resin sheet at a high speed. SOLUTION: In the method for producing a thermoplastic resin sheet, the method includes a step of bringing a thermoplastic resin extruded into a sheet shape from a die into close contact with a cooling rotator by an electrostatic application device to cool and solidify the thermoplastic resin sheet. A blade-like electrostatic application electrode extending in the width direction of the thermoplastic resin sheet is provided near the landing point of the rotating body, and the thermoplastic resin sheet is provided above at least one widthwise end of the thermoplastic resin sheet. The pressing means provided in the vicinity of the landing point on the cooling rotator presses the width direction end of the thermoplastic resin sheet toward the cooling rotator side, and the position of the landing point of the thermoplastic resin sheet in the cooling rotator circumferential direction. The thermoplastic resin sheet is made substantially uniform over the entire width of the thermoplastic resin sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a thermoplastic resin sheet in which a thermoplastic resin extruded from a die into a sheet shape is brought into close contact with a cooling rotating body and solidified by cooling.

[0002]

2. Description of the Related Art In a crystalline thermoplastic polymer such as polyethylene terephthalate, rapid cooling by bringing a thermoplastic resin extruded into a sheet shape from a die into close contact with a cooling rotating body can reduce the degree of crystallinity. It is important that if the crystallinity is excessively large, the sheet will become brittle or the sheet manufacturing operation in the subsequent process will be difficult, and the productivity will be significantly impaired. For this reason, a method of applying an electrostatic charge to the thermoplastic resin sheet has been widely used as a means for bringing the thermoplastic resin sheet into close contact with the cooling rotator when rapidly cooling the thermoplastic resin sheet.

[0003] As a specific method of applying an electrostatic charge,
Generally, an electrostatic application device provided with a wire-shaped electrode is known, and for example, there is one as described in JP-B-37-6142. In order to achieve high-speed production by further rotating the cooling rotator at high speed, an electrostatic application device using a blade-shaped electrode is known, for example, as described in JP-B-63-20688. Something like that.

In actual production of a thermoplastic resin sheet, in order to improve the productivity of the sheet, it is strongly required that the cooling rotating body be rotated at a high speed without impairing the quality of the sheet. In the method of applying an electrostatic charge to the resin sheet, it is important to efficiently apply more electrostatic charge to the thermoplastic resin sheet, and when the application of the electrostatic charge is insufficient, it is necessary to apply the electrostatic charge to the thermoplastic resin sheet. Adhesion with the cooling rotator becomes insufficient, causing a bubble-like defect in the sheet. On the other hand, if an attempt is made to apply an excessive amount of electrostatic charge, a pinhole-shaped defect occurs due to dielectric breakdown of the thermoplastic resin sheet, and as a result, the thermoplastic resin sheet becomes poor in quality, resulting in serious inconvenience in production. Invite.

On the other hand, as another method, a water film is interposed between the surface of the cooling rotator and the thermoplastic resin sheet,
A method of rotating the cooling rotator at a high speed is also known. For example, Japanese Patent Application Laid-Open No. 58-63415 and
No. 063 is disclosed.

A method of interposing a water film on a cooling rotating body is as follows.
Although it is effective as a method of rotating the cooling rotator at high speed, the mere interposition of only a water film deteriorates the flatness of the obtained sheet, and when the sheet is used as an unstretched sheet, it is further stretched. In such a case, stable film formation was not possible, and the film could not be actually used.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of stably obtaining a thermoplastic resin sheet at high speed and with high efficiency in view of the above problems. .

As a result of intensive studies to achieve this object,
When the cooling rotator was rotated at a high speed, the following problems were found. That is, as the cooling rotator rotates at a higher speed, both ends of the thermoplastic resin sheet (hereinafter, sometimes simply referred to as edges) are curled up, cracks at the edges due to poor cooling, and blade-like static. As a result, it was impossible to produce a thermoplastic resin sheet stably and continuously for a long period of time.

[0009]

In order to solve such a problem, the present invention comprises the following constitution. That is, claim 1
The method for producing a thermoplastic resin sheet according to the method for producing a thermoplastic resin sheet having a step of bringing a thermoplastic resin extruded into a sheet form from a die into a cooling rotating body by an electrostatic application device and cooling and solidifying the thermoplastic resin sheet, Near the landing point of the cooling rotator of the thermoplastic resin sheet, provided a blade-shaped electrostatic application electrode extending in the width direction of the thermoplastic resin sheet, above the width direction end of at least one of the thermoplastic resin sheet, And, by pressing means provided in the vicinity of the point of attachment of the thermoplastic resin sheet to the cooling rotator, the width direction end of the thermoplastic resin sheet is pressed toward the cooling rotator, and the position of the attachment point of the thermoplastic resin sheet is determined. The method is characterized in that the position in the circumferential direction of the cooling rotator is made substantially uniform over the entire width of the thermoplastic resin sheet.

[0010] According to a second aspect of the present invention, there is provided a method of manufacturing a thermoplastic resin sheet, comprising the steps of: adhering a thermoplastic resin extruded into a sheet shape from a die to a cooling rotary body by an electrostatic application device; and cooling and solidifying the thermoplastic resin. In the sheet manufacturing method, a blade-shaped electrostatic application electrode extending in the width direction of the thermoplastic resin sheet is provided near the landing point of the cooling rotator of the thermoplastic resin sheet, and the thermoplastic resin sheet and the cooling rotator are provided. And forming a water film having an average thickness of 0.1 μm or more and 3 μm or less.

According to a third aspect of the present invention, there is provided a method of manufacturing a thermoplastic resin sheet according to the above method, further comprising the step of cooling the thermoplastic resin sheet above at least one widthwise end of the thermoplastic resin sheet. By pressing means provided in the vicinity of the landing point on the thermoplastic resin sheet, the end in the width direction of the thermoplastic resin sheet is pressed toward the cooling rotator, and the position of the landing point of the thermoplastic resin sheet in the circumferential direction of the cooling rotator is made of the thermoplastic resin. The method is characterized in that the sheet is made substantially uniform over the entire width of the sheet.

According to a fourth aspect of the present invention, in any one of the above methods, the thermoplastic resin sheet on the cooling rotator is not subjected to a tension fluctuation from a post-process of the cooling rotator. In addition, the method is characterized in that a fluctuation in tension between the cooling rotary body and a subsequent process is blocked or absorbed.

According to a fifth aspect of the present invention, in any one of the above-mentioned methods, the thickness of the thermoplastic resin sheet on the cooling rotary body is 30 μm to 300 μm.
The method is characterized by the following.

According to a sixth aspect of the present invention, there is provided a method for producing a thermoplastic resin sheet according to any one of the above methods, wherein the thermoplastic resin is a polyester.

According to a seventh aspect of the present invention, there is provided a method for producing a thermoplastic resin sheet according to any one of the above methods, wherein the thermoplastic resin sheet is subjected to biaxial stretching and heat treatment to form a biaxially oriented film. Become.

According to a eighth aspect of the present invention, there is provided an apparatus for manufacturing a thermoplastic resin sheet, the method comprising a step of bringing the thermoplastic resin extruded into a sheet form from a die into close contact with a cooling rotating body by an electrostatic application device and cooling and solidifying the thermoplastic resin. In the sheet manufacturing apparatus, a blade-shaped electrostatic application electrode extending in the width direction of the thermoplastic resin sheet provided in the vicinity of the landing point of the thermoplastic resin sheet to the cooling rotator, and at least one of the thermoplastic resin sheets Pressing means for pressing the widthwise end of the thermoplastic resin sheet toward the cooling rotator, the pressing means being provided above the widthwise end and near the point of attachment of the thermoplastic resin sheet to the cooling rotator. It is characterized by the following.

According to a ninth aspect of the present invention, there is provided an apparatus for manufacturing a thermoplastic resin sheet, comprising the steps of: adhering a thermoplastic resin extruded into a sheet form from a die to a cooling rotating body by an electrostatic application device; and cooling and solidifying the thermoplastic resin. In the sheet manufacturing apparatus, a blade-like electrostatic application electrode extending in the width direction of the thermoplastic resin sheet provided in the vicinity of a point of attachment of the thermoplastic resin sheet to the cooling rotator, and the thermoplastic resin sheet and the cooling rotator And a water film forming apparatus for forming a water film having an average thickness of 0.1 μm or more and 3 μm or less.

According to a tenth aspect of the present invention, in the above-mentioned method, the thermoplastic resin sheet manufacturing apparatus further comprises: an upper part of at least one width direction end of the thermoplastic resin sheet;
It is characterized by having a pressing means provided near the point where the thermoplastic resin sheet is attached to the cooling rotator, for pressing the widthwise end of the thermoplastic resin sheet toward the cooling rotator.

In the apparatus for manufacturing a thermoplastic resin sheet according to the eleventh aspect, a gas ejection device is used as the pressing means.

In the apparatus for manufacturing a thermoplastic resin sheet according to a twelfth aspect, an electrostatic application device is used as the pressing means.

[0021] In the apparatus for manufacturing a thermoplastic resin sheet according to claim 13, the water film forming apparatus has a temperature of 70 ° C to 95 ° C.
A water film forming apparatus that blows saturated moist air of less than ° C onto the cooling rotating body is used.

According to a fourteenth aspect of the present invention, the water film remaining on the surface of the cooling rotator is removed before the water film is formed on the surface of the cooling rotator by the water film forming device. For removing the water film.

According to a fifteenth aspect of the present invention, in the thermoplastic resin sheet manufacturing apparatus, the cooling resin sheet on the cooling rotator is not subjected to a tension fluctuation from a post-process of the cooling rotator. A tension fluctuation preventing means for blocking or absorbing the fluctuation of the tension is included between the rotating body and the post-process.

[0024]

According to the method of manufacturing a thermoplastic resin sheet of the present invention, a blade-shaped electrostatic application electrode is provided near a point where the thermoplastic resin sheet is attached to the cooling rotating body, and at least one of the thermoplastic resin sheets is provided. By pressing the end portion of the thermoplastic resin sheet toward the cooling rotator side by pressing means provided near an end of the thermoplastic resin sheet to the cooling rotator at the width direction end of the thermoplastic resin sheet, In order to make the position of the landing point substantially uniform over the entire width, even if the cooling rotator is rotated at high speed for the purpose of improving the productivity of the sheet, the edge portion does not roll up and the thermoplastic resin sheet on the cooling rotator Can be continuously produced without impairing the moldability.

According to the method of manufacturing a thermoplastic resin sheet according to the second aspect, a blade-shaped electrostatic application electrode is provided near a point where the thermoplastic resin sheet is attached to the cooling rotating body, and the thermoplastic resin sheet and the cooling rotating body are provided. A water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between them, so that the adhesion of the thermoplastic resin sheet on the cooling rotator at the landing point is increased, and the sheet has a bubble-like defect. High-speed operation of the cooling rotator can be realized without generation of the cooling rotator.

According to the third aspect of the present invention, a blade-shaped electrostatic application electrode is provided near the point where the thermoplastic resin sheet is attached to the cooling rotary member, and the pressing means is used to press the thermoplastic resin sheet. After making the position of the landing point of the sheet substantially uniform over the entire width, a water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between the thermoplastic resin sheet and the cooling rotator. The cooling rotating body can be stably operated at extremely high speed without generating a bubble-like defect.

[0027] According to the method of manufacturing a thermoplastic resin sheet of the fourth aspect, the cooling rotator is provided so that the thermoplastic resin sheet on the cooling rotator is not subjected to a tension fluctuation from a post-process of the cooling rotator. In order to prevent tension fluctuation between the post-process and the post-process, it is possible to stably and continuously obtain a sheet having small thickness unevenness.

According to the method of manufacturing a thermoplastic resin sheet of the fifth aspect, a water film is interposed on the cooling rotator so that the thickness of the thermoplastic resin sheet on the cooling rotator is 30 μm or more and 300 μm or less. In this case, the problem that the flatness of the sheet becomes worse as the thickness of the thermoplastic resin sheet is generally increased, but since the thickness of the thermoplastic resin sheet is appropriate as described above, the deterioration of the flatness of the sheet can be prevented. As a result, stable production is possible even as an unstretched sheet or when stretching is performed in a subsequent step.

According to the method of manufacturing a thermoplastic resin sheet of the present invention, since polyester is used as the thermoplastic resin, a particularly good polyester product can be obtained.

According to the method for producing a thermoplastic resin sheet of the present invention, the thermoplastic resin sheet is subjected to biaxial stretching and heat treatment to produce a biaxially oriented film. Since the film can be molded at a high speed and excellent quality as described above, a film as a final product can be stably produced at a high speed and excellent quality.

According to the apparatus for manufacturing a thermoplastic resin sheet of the present invention, the blade-shaped electrostatic application electrode provided near the point of attachment of the thermoplastic resin sheet to the cooling rotating body, and at least one of the thermoplastic resin sheet Pressing means provided for pressing the end of the thermoplastic resin sheet toward the cooling rotator, above the one end in the width direction, and near the point of attachment of the thermoplastic resin sheet to the cooling rotator. Therefore, the position of the landing point of the thermoplastic resin sheet can be substantially uniform over the entire width. As a result, even when the cooling rotating body is rotated at a high speed, the edge portion does not roll up, and the blade-shaped electrostatic application electrode is The thermoplastic resin sheet can be stably and continuously produced without contact.

According to the thermoplastic resin sheet manufacturing apparatus of the ninth aspect, the blade-shaped electrostatic application electrode provided near the point where the thermoplastic resin sheet is attached to the cooling rotator, and the thermoplastic resin sheet further comprises: Since a water film forming device that forms a water film having an average thickness of 0.1 μm or more and 3 μm or less is included between the cooling rotator and the sheet, high-speed sheet forming can be performed stably without impairing the flatness of the sheet. It becomes possible. Here, when the thickness of the water film is less than 0.1 μm, since the adhesion force when the thermoplastic resin sheet separates from the cooling rotator is too strong, the sheet is torn, and the thickness of the water film exceeds 3 μm. In this case, there are problems that the flatness of the sheet becomes extremely poor, and the thermoplastic resin sheet slides on the cooling rotator to deteriorate the formability.

According to a tenth aspect of the present invention, there is provided an apparatus for manufacturing a thermoplastic resin sheet, comprising: a blade-shaped electrostatic application electrode provided in the vicinity of a point at which the thermoplastic resin is attached to the cooling rotary member; Since it includes the forming device, the thermoplastic resin sheet that lands on the cooling rotator is strongly adhered to the cooling rotator from the anti-cooling rotator side by the blade-shaped electrostatic application electrode and the pressing means. In addition to the above, since a water film having an average thickness of 0.1 μm or more and 3 μm or less can be formed by a water film forming apparatus, the adhesion at the point of attachment of the thermoplastic resin sheet on the cooling rotator further increases, and High-speed operation of the cooling rotator becomes possible without generating bubble-like defects.

According to the apparatus for manufacturing a thermoplastic resin sheet according to the eleventh aspect, since the gas ejecting device is used as the pressing means, the curving of the edge portion can be prevented with a relatively simple device.

According to the apparatus for manufacturing a thermoplastic resin sheet according to the twelfth aspect, since the electrostatic applying device is used for the pressing means, it is possible to prevent the edge from curling up with high accuracy and stability.

According to the apparatus for manufacturing a thermoplastic resin sheet according to the thirteenth aspect, since the water film forming apparatus uses the water film forming apparatus for blowing saturated humid air of 70 ° C. or more and less than 95 ° C. to the cooling rotating body, Since the water film on the surface of the cooling rotator can be formed by condensation of very fine water droplets, the water film thickness can efficiently and easily obtain an extremely thin optimum range having an average thickness of 0.1 μm or more and 3 μm or less. When the temperature of the humid air is constant, the amount of water contained in the humid air can be uniquely determined with respect to the amount of the humid air because saturated humid air is used. By adjusting the amount of air, the thickness of the water film can be easily controlled.

According to the apparatus for manufacturing a thermoplastic resin sheet of the present invention, before the water film is formed on the surface of the cooling rotator by the water film forming device, the water film remaining on the surface of the cooling rotator is removed. Since a water film removing device is included, when a water film is formed on the surface of the cooling rotator by the water film forming device, the water film remaining over the entire width is not affected by the water film. Since the thickness of the water film at the landing point of the plastic resin sheet can always maintain a constant water film thickness, the quality and productivity of the sheet can be improved.

According to the apparatus for manufacturing a thermoplastic resin sheet of the present invention, the thermoplastic resin sheet on the cooling rotator is not affected by the tension fluctuation from the post-process of the cooling rotator.
Since a tension fluctuation preventing means is included between the cooling rotator and the post-process, even if a tension fluctuation occurs in the post-process, the thermoplastic resin on the cooling rotator can be stably produced without being affected. It becomes possible.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. First, as the thermoplastic resin in the present invention, for example, polyethylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene α, β-bis ( Polyesters such as 2-chlorophenoxy) ethane 4,4-dicarboxylate, polyolefins such as polyethylene, polypropylene, polybutene and poly-4-methylpentene-1, polyamides such as nylon 6, nylon 66 and nylon 12, polyimide , Polysulfones, polystyrenes, polyvinyls, polyester ethers, polycarbonates, polyester carbonates, polyether sulfones, polyetherimides, polyphenylene Sulfides and the like can be used. These resins may be used alone or as a copolymer or a mixture. Of course, these thermoplastic resins may contain other additives, for example, an antistatic agent, a weather-resistant material, a lubricant made of inorganic or organic particles, wax, or the like, a pigment, or the like.

The present invention is effective when the thermoplastic resin is a polyester among the above-mentioned ones, particularly, mainly polyethylene terephthalate, polyethylene isophthalate and polyethylene-2,6-naphthalate. Here, “mainly” indicates that the polyester is contained in an amount of 70 mol% or more. The polyester may be a single polyester, a copolymer, or a simple mixture of other components at a ratio of less than 30 mol%.

FIG. 1 shows a general configuration of an apparatus for producing a thermoplastic resin sheet to which the present invention can be applied. In FIG. 1, a thermoplastic resin supplied from an extruder (not shown) is widened in a width direction by a base 1 and then discharged in the form of a thermoplastic resin sheet 3. The thermoplastic resin sheet 3 is quenched after landing on the cooling rotator 2. In the present invention, the blade-shaped electrostatic application electrode 4 is placed near the landing point 8 of the thermoplastic resin sheet 3 on the cooling rotator 2. Provided. The position of the landing point 8 differs depending on the relative positional relationship between the base 1 and the cooling rotator 2, the thickness of the thermoplastic resin sheet 3, and the rotation speed of the cooling rotator 2. The blade-shaped electrostatic applying electrode 4 is connected to a DC high-voltage power supply 7, and supplies a DC high voltage to the flared electrostatic applying electrode 4 to generate electrostatic charges generated from the blade-shaped electrostatic applying electrode 4. Is applied to the thermoplastic resin sheet 3, and the Coulomb force causes the thermoplastic resin sheet 3 to adhere to the surface of the cooling rotator 2.

FIGS. 2 and 3 show an apparatus for manufacturing a thermoplastic resin sheet according to an embodiment of the present invention. As shown in FIG. 3, the blade-shaped electrostatic application electrodes 4 are provided over substantially the entire width of the thermoplastic resin sheet 3. The insulating member 5 is provided in order to avoid the electric discharge. The closer to the cooling rotator 2, the more efficiently the blade-like electrostatic application electrode 4 can apply an electrostatic charge to the thermoplastic resin sheet 3. However, when the cooling rotator 2 is rotated at a high speed, the landing point 8 becomes thermoplastic. Depending on the position in the width direction of the resin sheet 3, the position is different in the circumferential direction of the cooling rotator 2. Therefore, in order to avoid the contact between the thermoplastic resin sheet 3 and the blade-like electrostatic application electrode 4, it is necessary to apply the electrostatic application. It is necessary to increase the clearance between the electrode 4 and the cooling rotator 2.

More specifically, when the cooling rotator 2 is rotated at a high speed for the purpose of improving the productivity, the widthwise end portion of the thermoplastic resin sheet 3 is compared with the portion other than the end portion of the thermoplastic resin sheet 3. , The end of the thermoplastic resin sheet 3 is turned up, so that the blade-shaped electrostatic application electrode 4
In order to avoid contact with the cooling rotor 2
Need to be kept away from In this case, as described above, since the electrostatic charge from the blade-shaped electrostatic application electrode 4 cannot be efficiently applied to the thermoplastic resin sheet 3, the rotation speed of the cooling rotator 2 naturally has a limit.

In the present invention, the pressing means 9 is provided at at least one edge near the end 8 where the end of the thermoplastic resin sheet 3 is attached to the cooling rotator 2. The blade-shaped electrostatic applying electrode 4 can be prevented from rising up, and the blade-shaped electrostatic applying electrode 4 can be brought as close as possible to the cooling rotator 2. As a result, the electrostatic charge from the blade-shaped electrostatic applying electrode 4 is transferred to the thermoplastic resin. The cooling rotator 2 can be applied efficiently to the sheet 3 and can be rotated at a high speed.

FIGS. 2 and 3 show one embodiment of the pressing means 9 in which at least one of the ends of the thermoplastic resin sheet 3 is provided in accordance with the curving condition of the end of the thermoplastic resin sheet 3. It is made of a heat-resistant resin or the like so that air compressed by a compressor or the like can be blown toward the vicinity of a landing point on the cooling rotator 2 at the end of the thermoplastic resin sheet 3 after controlling the pressure and the flow rate. 1 shows an apparatus using a gas ejection device.

Further, another embodiment may be used as the pressing means. For example, as shown in FIG. 4, a needle-shaped electrostatic application electrode 10 is attached to at least one of the widthwise ends of the thermoplastic resin sheet 3 at a point 8 where the end of the thermoplastic resin sheet 3 is attached to the cooling rotator 2. By controlling the voltage of the DC high-voltage power supply 11 connected to the needle-shaped electrostatic application electrode 10 and provided near the end, it is possible to suppress the curling up of the end of the thermoplastic resin sheet 3 and to form a long-term stable film. Becomes

FIG. 5 shows a thermoplastic resin sheet manufacturing apparatus according to another embodiment of the present invention. A blade-shaped electrostatic application electrode 4 is provided in the vicinity of a point 8 where the thermoplastic resin sheet 3 is attached to the cooling rotator 2, and the upstream side of the point 8 where the thermoplastic resin sheet 3 is attached to the cooling rotator 2. Is provided with a water film forming device 12, and a water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between the thermoplastic resin sheet 3 and the cooling rotator 2 using the water film forming device 12. I am trying to do it. A so-called meniscus is formed at the landing point 8 between the thermoplastic resin sheet 3 and the cooling rotator 2 due to the formed water film, and the accompanying airflow of the cooling rotator 2 causes the thermoplastic resin sheet 3 and the cooling rotator 2 to flow. In order to prevent intrusion into the landing point 8, even if the cooling rotator 2 is rotated at a high speed, the thermoplastic resin sheet 3 can be produced without generating bubble-like defects,
Furthermore, since the blade-shaped electrostatic application electrode 4 is provided, the landing point 8 of the thermoplastic resin sheet 3 to the cooling rotator 2
The variation in the circumferential direction of the cooling rotator can be prevented over the entire width, so that a thermoplastic resin sheet with less unevenness in thickness can be obtained. Here, it goes without saying that the cooling rotator 2 can be further rotated at a high speed if the above-described pressing means 9 is used in combination.

As an embodiment of the water film forming device 12,
A water film forming apparatus 12 that forms a water film by blowing saturated moist air of 0 ° C. or more and less than 95 ° C. onto the cooling rotator 2 to cause dew condensation on the surface of the cooling rotator 2 can be used. In such a water film forming apparatus 12, since water droplets generated on the surface of the cooling rotator 2 due to condensation are extremely fine, a water film having an average thickness of 0.1 μm or more and 3 μm or less can be easily formed. . Here, by using humid air having a temperature of 70 ° C. or more and less than 95 ° C., for example, the temperature difference between the cooling rotator 2 and the cooling rotator 2 which is maintained at a substantially constant temperature between 10 ° C. and 30 ° C. is large, so that dew condensation is efficiently performed Furthermore, if saturated humid air with a constant temperature is used, the amount of dew condensation can be uniquely determined by the amount of humid air, which is extremely convenient during production.

FIG. 6 shows still another embodiment of the present invention. In the embodiment shown in FIG. 6, in addition to the embodiment of FIG. 5, a water film removing device 13 is provided between a position where the thermoplastic resin sheet 3 separates from the cooling rotator 2 and the water film forming device 12. As the water film removing device 13, for example, a mass roll (manufactured by Masuda Seisakusho Co., Ltd.) as a water absorbing roll is pressure-bonded to the cooling rotator 2 and connected to a suction device such as a vacuum pump to remove residual water. The water film removing device 13
In order to remove the water film remaining on the cooling rotator 2 when the thermoplastic resin sheet 3 separates from the cooling rotator 2, the water film forming device 12 is not affected by the remaining water when forming the water film, A constant water film thickness can always be maintained. Since the water film remaining on the cooling rotator 2 when the thermoplastic resin sheet 3 separates from the cooling rotator 2 remains irregularly, the water film forming device 12 avoids the remaining water film and selectively removes the water film. It is impossible to form a film, and the remaining water film becomes uneven in water film thickness as it is. Therefore, in actual production, removing the remaining water film is extremely important for obtaining a sheet having excellent flatness. It becomes something.

FIG. 7 shows still another embodiment of the present invention. In the embodiment shown in FIG. 7, a tension fluctuation preventing means 14 is provided between the cooling rotator 2 and a subsequent process. In the example shown in FIG. 7, the roll immediately after the cooling rotator 2 is provided with a suction hole (not shown) capable of sucking and pressing the thermoplastic resin sheet 3. However, there is provided a drive device (not shown) which can be driven in conjunction at substantially the same speed. For this reason, since the tension from the post-process temporarily holds the tension on the roll, the tension between the roll and the cooling rotator 2 can always be kept constant even if the tension from the post-process varies. . In other words, tension fluctuations from the post-process can be blocked by the rolls, and the rolls function as tension fluctuation prevention means 14 for blocking tension fluctuations. Needless to say, instead of complete interruption, a means capable of absorbing most of the tension fluctuation may be used. With such a tension fluctuation preventing means 14, the thermoplastic resin sheet 3 on the cooling rotator 2 is not affected by the tension fluctuation from the subsequent step, and even if there is a water film between the thermoplastic rotator 2 and the cooling rotator 2, Since the plastic resin sheet 3 can be stably produced without slipping on the cooling rotator 2, a high-quality sheet with less unevenness in thickness can be stably produced at high speed.

In the present invention, the thickness of the thermoplastic resin sheet 3 on the cooling rotator 2 is 30 μm or more and 300 μm or more.
If it is not more than μm, even if a water film is formed between the thermoplastic resin sheet 3 and the cooling rotator 2, a high-quality product can be obtained without impairing the flatness of the sheet. When polyester is used as the thermoplastic resin, the blade-shaped electrostatic application electrode 4 effectively adheres to the cooling rotator 2, so that productivity and quality are greatly improved, which is preferable.

It is also preferable to subject the thermoplastic resin sheet obtained in the present invention to biaxial stretching and heat treatment to form a biaxially oriented film. The method of biaxial stretching and heat treatment is not particularly limited, but as a typical method, a thermoplastic resin sheet is heated to a glass transition temperature or higher, and a low-speed, high-speed stretching roll is provided between stretching rolls, in one stage or in multiple stages. After stretching in the longitudinal direction, the longitudinally stretched film obtained by cooling is gripped by a clip, and the film is gripped by a tenter of a type in which the film is run. it can.

The material of the blade-shaped electrostatic application electrode of the present invention includes a simple metal such as iron, nickel, molybdenum, tungsten, cobalt, chromium, and zirconium, and at least one of the above components. (For example, stainless steel, duralumin, etc.) or the above-mentioned metal simple substance or an alloy plated with an alloy, among which inexpensive stainless steel is practical and preferable. Further, as for the shape, in the cross section, the width is 2 to 20 mm, the thickness is 0.01 to 1 mm, and the width /
It is preferable that the thickness ratio is 50 to 1000 from the viewpoint of handling properties, strength, and improvement of electrostatic application property due to concentration of electrostatic charge. Further, it is preferable to apply tension to both ends so that the electrodes are not significantly deformed in order to prevent the electrodes from vibrating.

[0054]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
With respect to the apparatus for manufacturing a thermoplastic resin sheet according to the present invention and another comparative example, a test was conducted to compare the occurrence of surface defects of the sheet using polyester as the thermoplastic resin.
Table 1 shows the results.

[0055]

[Table 1]

As shown in Comparative Example 1, when the blade-shaped electrostatic application electrode 4 was used, the peripheral speed of the cooling rotator 2 was 9
Although the surface state of the thermoplastic resin sheet 3 was good even at 2 m / min, as shown in Comparative Example 2, when the peripheral speed of the cooling rotator 2 was set to 95 m / min, the edge curling started. Further high-speed operation was difficult.

On the other hand, in the first embodiment of the present invention, the pressing means 9
As a gas ejecting device made of a heat-resistant resin or the like is used to eject the thermoplastic resin sheet 3 toward the vicinity of the point of attachment to the cooling rotator 2 at the end, the curving of the edge portion is suppressed. And the peripheral speed of the cooling rotator 2 is
Although the speed could be increased to m / min, the edge portion fluctuated slightly, and further high-speed operation was impossible.

In the second embodiment of the present invention, the needle-shaped electrostatic application electrode 10 is provided as the pressing means 9 in the vicinity of the end of the thermoplastic resin sheet 3 near the landing point on the cooling rotator 2. The peripheral speed of the cooling rotator 2 is 111 m
Even when the speed was increased to / min, stable film formation was possible.

In the third embodiment of the present invention, a blade-shaped electrostatic application electrode 4 is provided in the vicinity of a point 8 where the thermoplastic resin sheet 3 is attached to the cooling rotator 2. Since the water film forming device 12 is provided on the upstream side of the landing point of the cooling rotator 2, the peripheral speed of the cooling rotator 2 is set to 11
Even when the speed was increased to 9 m / min, the film could be formed without generating bubble-like defects in the sheet, but due to the residual water of the water film forming device 12 over time, the flatness of the sheet deteriorated, Was difficult to form continuously. As the water film forming device 12, a water film forming device that forms a water film by spraying saturated humid air of 70 ° C. or more and less than 95 ° C. onto the cooling rotator 2 to cause dew condensation on the surface of the cooling rotator 2 was used. ,
Water droplets generated on the surface of the cooling rotator 2 due to condensation were extremely fine, and a water film having an average thickness of 0.1 μm or more and 3 μm or less could be easily formed.

In the fourth embodiment of the present invention, in addition to the third embodiment, a needle-shaped electrostatic application electrode 10 is provided as a pressing means in the vicinity of the end of the thermoplastic resin sheet 3 near the landing point on the cooling rotator 2. Although the peripheral speed of the cooling rotator 2 could be further increased to 128 m / min, the flatness of the sheet deteriorated due to the residual water of the water film forming device 12 with the lapse of time as in the third embodiment, and the Continuous film formation was difficult.

In the fifth embodiment of the present invention, the water film removing device 13
Is provided between the position where the thermoplastic resin sheet 3 separates from the cooling rotator 2 and the water film forming device 12, and the thermoplastic resin sheet 3 remains on the cooling rotator 2 when separating from the cooling rotator 2. Since the water film formed can be removed, long-term continuous film formation can be performed at a high rotational speed of the cooling rotator 2 of 130 m / min. However, when there is a fluctuation in tension from the subsequent step, since a water film is formed between the thermoplastic resin sheet 3 and the cooling rotator 2, the thermoplastic resin sheet 3 Slippage and uneven thickness worsened.

In the sixth embodiment of the present invention, the cooling rotator 2 is used as the tension fluctuation preventing means 14 between the cooling rotator 2 and the subsequent process.
A roll having a suction hole capable of sucking and pressing the thermoplastic resin sheet 3 is provided on the roll immediately after the above, and a driving device capable of driving the roll in conjunction with the cooling rotator 2 is provided. Can be once held by the rolls, so that long-term continuous film formation can be performed at a high speed of 130 m / min at a peripheral speed of the cooling rotator 2 without deteriorating thickness unevenness.

[0063]

According to the first aspect of the present invention, when the thermoplastic resin sheet is brought into close contact with the cooling rotator and rotated at high speed by using the blade-shaped electrostatic applying electrode, the blade-shaped electrostatic applying electrode is used. In order to efficiently apply electrostatic charges from the thermoplastic resin sheet to the thermoplastic resin sheet, in addition to the blade-shaped electrostatic application electrodes, the thermoplastic resin is cooled by pressing means provided near the edge of the thermoplastic resin sheet at the landing point. Since the landing point on the rotating body can be made substantially uniform over the entire width, there is a specific effect that high-speed operation of the cooling rotating body can be achieved without deteriorating the quality of the seat.

According to the second aspect of the present invention, a water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between the thermoplastic resin sheet and the cooling rotator in addition to the blade-shaped electrostatic application electrode. Since the cooling rotator is formed, the cooling rotator can be rotated at a high speed without generating a bubble-like defect in the sheet.

According to the third aspect of the present invention, in addition to the blade-shaped electrostatic application electrode, pressing means provided near the edge of the thermoplastic resin sheet at the landing point is used to cool the thermoplastic resin sheet rotating body. Can be made substantially uniform over the entire width, and furthermore, a water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between the thermoplastic resin sheet and the cooling rotating body. There is a specific effect that the cooling rotator can be rotated at a higher speed without generating a defect.

According to the fourth aspect of the present invention, the thermoplastic resin sheet on the cooling rotator does not receive the fluctuation of the tension from the post-process of the cooling rotator. Since the tension fluctuation can be prevented between the thermoplastic resin sheet and the cooling rotator, even if there is a water film between the thermoplastic resin sheet and the cooling rotator, since the thermoplastic resin sheet does not slide on the cooling rotator due to the tension fluctuation, the sheet with less thickness unevenness. It has a specific effect that it can be manufactured.

According to the fifth aspect of the present invention, the thickness of the thermoplastic resin sheet on the cooling rotator is not less than 30 μm and not more than 300 μm.
μm or less, even if a water film is formed between the thermoplastic resin sheet and the cooling rotator, the flatness of the sheet is not impaired, so a unique effect that a high quality product can be obtained. To play.

According to the sixth aspect of the invention, since the polyester is used as the thermoplastic resin, the sheet effectively adheres to the cooling rotating body, so that the unique effect that productivity and quality are greatly improved is obtained. Play.

According to the seventh aspect of the present invention, a unique effect that a high-quality biaxially stretched film having excellent productivity can be obtained.

According to the eighth aspect of the present invention, the blade-shaped electrostatic application electrode is provided near the point of attachment of the thermoplastic resin sheet to the cooling rotator. In the vicinity of the landing point, there is provided a pressing means for pressing the end of the thermoplastic resin sheet toward the cooling rotator, so that the landing point of the thermoplastic resin sheet on the cooling rotator can be made substantially uniform over the entire width. In addition, there is a specific effect that high-speed operation of the cooling rotator can be achieved without impairing the quality of the seat.

According to the ninth aspect of the present invention, a water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between the thermoplastic resin sheet and the cooling rotator in addition to the blade-shaped electrostatic application electrode. Since the water film forming apparatus for forming is used, even when the cooling rotating body is rotated at a high speed, there is a specific effect that a film can be formed without generating a bubble-like defect in the sheet.

According to the tenth aspect of the present invention, a blade-shaped electrostatic application electrode is provided in the vicinity of the point of attachment of the thermoplastic resin sheet to the cooling rotator, and further, the thermoplastic resin sheet is attached to the cooling rotator. In the vicinity of the point, a pressing means for pressing the end of the thermoplastic resin sheet toward the cooling rotator is provided, and the average thickness between the thermoplastic resin sheet and the cooling rotator is 0.1 μm or more and 3 μm or less. Since the water film forming apparatus that forms the water film is also used, a unique effect is obtained in that the film can be formed by further rotating the cooling rotator at a higher speed without generating a bubble-like defect in the sheet.

According to the eleventh aspect of the present invention, since the gas ejection device for ejecting compressed air is used for the pressing means,
It is possible to prevent the edge portion from being curled up by a relatively simple device, and to achieve a unique effect that the cooling rotator can be rotated at a high speed.

According to the twelfth aspect of the present invention, since the electrostatic application electrode is used as the pressing means, a unique effect that the edge portion can be prevented from being turned up stably even when the film is continuously formed for a long time can be obtained. .

According to the thirteenth aspect of the present invention, since the water film forming device is a water film forming device for blowing saturated humid air having a temperature of 70 ° C. or more and less than 95 ° C. onto the cooling rotary member, the water film thickness is an average thickness. Can efficiently and easily obtain the optimum range of 0.1 μm or more and 3 μm or less, and furthermore, when the temperature of the humid air is constant, since saturated humid air is used, the amount of water contained in the humid air Can be uniquely determined,
By adjusting the amount of humid air in accordance with the rotation speed of the cooling rotator, there is a unique effect that the thickness of the water film can be easily controlled.

According to the invention of claim 14, further,
Before the water film is formed on the surface of the cooling rotator by the water film forming device, a water film removing device for removing the water film remaining on the surface of the cooling rotator is provided. At the time of formation, since a constant water film thickness can be always maintained without being affected by residual water, a unique effect that continuous film formation can be performed for a long time is exhibited.

According to the invention of claim 15, further,
Since the thermoplastic resin sheet on the cooling rotator is not subjected to a tension change from a post-process of the cooling rotator, a tension fluctuation preventing means is provided between the cooling rotator and the post-process,
A unique effect is obtained in that the thermoplastic resin sheet does not slide on the cooling rotator, and a sheet with small thickness unevenness can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet to which the present invention can be applied.

FIG. 2 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet according to an embodiment of the present invention.

FIG. 3 is a schematic front view of the apparatus of FIG. 2;

FIG. 4 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet according to another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet according to still another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet according to still another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of an apparatus for manufacturing a thermoplastic resin sheet according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 2 Cooling rotating body 3 Thermoplastic resin sheet 4 Blade-like electrostatic application electrode 5 Insulating member 7 DC high-voltage power supply of blade-like electrostatic application electrode 8 Landing point 9 Pressing means 10 Needle-like electrostatic application electrode 11 Needle DC high-voltage power supply for electrode in electrostatic shape 12 Water film forming device 13 Water film removing device 14 Tension fluctuation preventing means

Claims (15)

[Claims] 1. A method for producing a thermoplastic resin sheet, comprising a step of bringing a thermoplastic resin extruded into a sheet form from a die into close contact with a cooling rotator by an electrostatic application device and cooling and solidifying the thermoplastic resin sheet. Near the landing point of the cooling rotator,
A blade-shaped electrostatic application electrode extending in the width direction of the thermoplastic resin sheet is provided, and a landing point on at least one width direction end of the thermoplastic resin sheet and the cooling resin rotating body of the thermoplastic resin sheet. By pressing means provided in the vicinity, the width direction end of the thermoplastic resin sheet is pressed against the cooling rotator side, and the position of the landing point of the thermoplastic resin sheet in the circumferential direction of the cooling rotator is substantially over the entire width of the thermoplastic resin sheet. A method for producing a thermoplastic resin sheet, characterized in that the sheet is made uniform. 2. A method for producing a thermoplastic resin sheet, comprising a step of bringing a thermoplastic resin extruded into a sheet form from a die into close contact with a cooling rotator by an electrostatic application device and cooling and solidifying the thermoplastic resin sheet. Near the landing point of the cooling rotator,
A blade-shaped electrostatic application electrode extending in the width direction of the thermoplastic resin sheet is provided, and a water film having an average thickness of 0.1 μm or more and 3 μm or less is formed between the thermoplastic resin sheet and the cooling rotator. A method for producing a thermoplastic resin sheet. 3. A pressing means provided above at least one widthwise end of the thermoplastic resin sheet and in the vicinity of a point where the thermoplastic resin sheet comes into contact with the cooling rotator. 3. The heat according to claim 2, wherein the end in the width direction is pressed against the cooling rotator so that the position of the thermoplastic resin sheet landing point in the circumferential direction of the cooling rotator is made substantially uniform over the entire width of the thermoplastic resin sheet. A method for producing a plastic resin sheet. 4. The thermoplastic resin sheet on the cooling rotator,
4. The cooling rotator according to claim 1, wherein the tension fluctuation is interrupted or absorbed between the cooling rotator and a post-process so as not to receive a tension fluctuation from a post-process of the cooling rotator. A method for producing a thermoplastic resin sheet. 5. The method for producing a thermoplastic resin sheet according to claim 1, wherein the thickness of the thermoplastic resin sheet on the cooling rotator is 30 μm or more and 300 μm or less. 6. The method for producing a thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin is a polyester. 7. The method for producing a thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin sheet is subjected to biaxial stretching and heat treatment to form a biaxially oriented film. 8. A thermoplastic resin sheet manufacturing apparatus comprising a step of bringing a thermoplastic resin extruded into a sheet shape from a mouthpiece into close contact with a cooling rotator by an electrostatic application device and cooling and solidifying the thermoplastic resin. A blade-shaped electrostatic application electrode extending in the width direction of the thermoplastic resin sheet provided in the vicinity of the point of attachment to the cooling rotator; and at least one width direction end of the thermoplastic resin sheet and the thermoplastic resin Pressing means for pressing a widthwise end of the thermoplastic resin sheet toward the cooling rotator, the pressing means being provided near a point where the resin sheet is attached to the cooling rotator. . 9. A thermoplastic resin sheet manufacturing apparatus comprising a step of bringing a thermoplastic resin extruded into a sheet shape from a die into close contact with a cooling rotator by an electrostatic applying device to cool and solidify the thermoplastic resin. A blade-like electrostatic application electrode extending in the width direction of the thermoplastic resin sheet provided in the vicinity of the point of attachment to the cooling rotator; and an average thickness of 0.1 μm between the thermoplastic resin sheet and the cooling rotator. An apparatus for producing a thermoplastic resin sheet, comprising: a water film forming apparatus for forming a water film having a thickness of 3 μm or less. 10. The width direction of the thermoplastic resin sheet, which is provided above at least one width direction end of the thermoplastic resin sheet and in the vicinity of a point of attachment of the thermoplastic resin sheet to the cooling rotating body. The apparatus for producing a thermoplastic resin sheet according to claim 9, further comprising a pressing unit that presses an end portion toward the cooling rotator. 11. The apparatus for manufacturing a thermoplastic resin sheet according to claim 8, wherein the pressing means is a gas ejection device. 12. The thermoplastic resin sheet manufacturing apparatus according to claim 8, wherein said pressing means is an electrostatic application device. 13. The method according to claim 13, wherein the water film forming apparatus is at 70 ° C. or higher and 95% or higher.
The apparatus for producing a thermoplastic resin sheet according to any one of claims 9 to 12, wherein the apparatus is a device that blows saturated moist air having a temperature of less than 0 ° C to the cooling rotating body. 14. A film removing device for removing a water film remaining on the cooling rotator surface before forming a water film on the cooling rotator surface by the water film forming device. An apparatus for producing a thermoplastic resin sheet according to any one of claims 9 to 13. 15. A means for blocking or absorbing tension fluctuation between the cooling rotator and the post-process so that the thermoplastic resin sheet on the cooling rotator does not receive the tension fluctuation from the post-process of the cooling rotator. The apparatus for producing a thermoplastic resin sheet according to any one of claims 8 to 14, wherein is provided.