JP2002326242A - Resin film manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin film manufacturing method capable of stably manufacturing a resin film of high quality at a high speed by properly adjusting the thickness of the water film of a casting drum. SOLUTION: The casting drum 1, a resin supply device 2 for supplying a molten resin 2a to the casting drum 1, a water film forming device 10 for forming the water film on the casting drum 1 and a water film measuring instrument 20 for measuring the thickness of the water film on the casting drum 1 are provided. The water film forming device 10 adjusts the thickness of the water film formed on the casting drum 1 on the basis of the measuring result of the water film measuring instrument 20. The water film measuring instrument 20 is arranged at the position where the water film is interposed between the casting drum 1 and the resin film 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a resin film, and more particularly to a method for manufacturing a resin film using a casting drum.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a resin film at a high speed, there has been known a method in which a thin film of water is formed on the surface of a casting drum, and a molten resin is cast on the water film to form a sheet. ing. An apparatus for carrying out this manufacturing method generally includes a rotating casting drum, a water film forming section for forming a water film on the surface of the casting drum, and a sheet-like sheet formed on a casting drum on which the water film is formed. The apparatus includes a resin supply unit for extruding the molten resin, a water film removal unit for removing a water film on the surface of the casting drum, and a water film measurement unit for measuring the thickness of the water film formed on the surface of the casting drum.

The above-mentioned water film measuring section is, for example, disclosed in Japanese Patent Laid-Open No. 5-293874 between a resin supply section and a water film forming section.
In Japanese Patent Application Laid-Open Publication No.
No. 71661 proposes a device equipped with an infrared moisture meter.

In the above-mentioned conventional manufacturing method, it is necessary to appropriately adjust the thickness of the water film formed on the surface of the casting drum. For example, when the thickness of the water film is large, the resin film slides on the casting drum, causing scratches and uneven thickness in the width direction and the flow direction of the resin film, so that a high-quality resin film cannot be manufactured.

On the other hand, when the thickness of the water film is small, the adhesion between the casting drum and the resin film becomes large, so that the resin film is hardly peeled off from the casting drum, and troubles such as film breakage are likely to occur.

To solve these problems, for example, there is a method of arranging a water film measuring section between a resin supply section and a water film forming section to measure the thickness of the water film. There is a problem that the correlation between the thickness of the water film and the measurement result of the water film measurement unit is lost depending on the thickness of the water film.

In Japanese Patent Application Laid-Open No. 6-71661,
A method for measuring the thickness of the water film interposed between the casting drum and the resin film by providing an infrared moisture meter in the water film measurement unit has been proposed, but it is not until a concrete configuration or effect is described. Not in.

For this reason, for example, Japanese Patent Application Laid-Open No. 5-92471
Japanese Patent Application Laid-Open No. 6-71661 proposes a method for adjusting the tension of a sheet when the sheet is separated from the casting drum. A method that is not based on the measurement result of the water film measuring unit, such as a method of adjusting the thickness of the water film in a predetermined relationship, is used.

However, since the water film formed on the surface of the casting drum is a thin film, it is sensitive to changes in the surrounding environment such as temperature, humidity, and air flow, and the thickness tends to change, so that the thickness of the water film can be accurately measured. With the conventional technology that cannot be used, it is substantially difficult to appropriately adjust the thickness of the water film.

[0010]

Accordingly, an object of the present invention is to develop a method for accurately measuring the thickness of a water film formed on the surface of a casting drum.

An object of the present invention is to provide a method for producing a resin film capable of producing a high-quality resin film at high speed and stably by employing a method for accurately measuring the thickness of a water film formed on the surface of a casting drum. It is in.

[0012]

According to the present invention, there is provided a method for producing a resin film, comprising: forming a water film on a surface of a molten resin to form a sheet on a casting drum. A method of manufacturing a resin film, comprising forming a sheet into a sheet while adjusting the thickness of the water film interposed between the casting drum and the sheet.

More specifically, the method for producing a resin film of the present invention is characterized in that the method comprises the steps of: forming a water film on the surface of a molten resin into a sheet on a casting drum; a) measuring the thickness of the water film interposed between the casting drum and the sheet, (b) measuring the thickness of the sheet, (c)
Correcting the measurement result of the thickness of the water film based on the measurement result of the thickness of the sheet-like material, (d) adjusting the thickness of the water film based on the measurement result of the corrected thickness of the water film. This is a method for producing a characteristic resin film.

[0014]

Next, a method for producing a resin film of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view illustrating an apparatus for manufacturing a resin film according to the present invention, particularly illustrating a casting portion for forming a molten resin into a resin film.

In FIG. 1, the apparatus for producing a resin film includes a casting drum 1, a resin supply apparatus 2, an electrostatic applying apparatus 3, a water film forming apparatus 10, and a water film measuring apparatus 20.
It is mainly composed of

The resin supply device 2 uses a heat bolt and a manual bolt to adjust the gap for supplying the molten resin 2a, and is arranged so as not to contact upward from the rotation center of the casting drum 1. From the resin supply device 2, the molten resin 2 a is supplied to the casting drum 1.

As the electrostatic application device 3, a wire system using a wire electrode was used. In addition, a tape method using a tape-shaped electrode can be used.

The water film forming apparatus 10 employs a method in which humid air is blown onto the surface of the casting drum 1. The amount of air to be blown was adjusted in a predetermined relationship depending on the rotation speed of the casting drum 1. In addition, as the water film forming apparatus 10, a method of applying a coater such as a reverse roll or a gravure roll can be used. In addition,
The water film forming device 10 is provided with a device (not shown) for removing a water film remaining on the casting drum 1.

The water film measuring device 20 is disposed in a section from the time when the molten resin 2a is cast on the casting drum 1 until the molten resin 2a is separated. In the above section, the water film formed on the casting drum 1 is in a state of being sandwiched between the casting drum 1 and the resin film 2b. If the water film is in the above-mentioned state, the water film measuring device 20 can be arranged at any position.
The position below the rotation center is good. By arranging the water film measuring device 20 at the above-mentioned position, it is hardly affected by the heat from the resin supply device 2 having a high temperature, and can be used continuously for a long time without having a special cooling mechanism or heat resistant mechanism, and The operability of attaching and detaching and adjusting the resin supply device 2 and the electrostatic application device 3 is not reduced. More preferably, the water film measuring device 2
0 is preferably arranged on the operation side of the resin supply device 2. Compared to the case where the device is arranged on the non-operation side, the facility cost can be reduced because there are fewer restrictions on the device arrangement, and the maintenance work of the water film measuring device 20 can be performed safely and easily without stopping the manufacturing process. be able to.

The water film measuring device 20 has a mechanism (cylinder 2 in FIG. 1) for keeping it away from the casting drum 1.
It is better to have 3). By moving the water film measuring device 20 to a position away from the casting drum 1, the maintenance work of the casting drum 1 and the water film measuring device 20 and the operation of passing the resin film 2b to the subsequent process can be performed safely and easily. Further, it is preferable that the water film measuring device 20 is provided with a mechanism (a linear guide 21 and a motor 22 in FIG. 1) for moving in the width direction of the resin film 2b. Resin film 2
By moving in the width direction of b and measuring the thickness of the water film, a method of adjusting the thickness of the water film can be selected from a plurality of methods according to the distribution of the thickness of the water film in the width direction.

It is preferable to use a polarized infrared moisture meter (manufactured by Kurashiki Boseki Co., Ltd.) for the measuring section of the water film measuring device 20.
The thickness of the water film and the resin film 2
A filter for measuring the thickness of the casting drum 1 is incorporated, and a three-wavelength method is used to reduce the influence of a change in the state of the surface of the casting drum 1.

The water film measuring device 20 calculates the water film thickness corrected for the influence of the resin film 2b based on the measurement results of the water film thickness and the resin film 2b thickness. For example, assuming that the measurement result of the water film is W and the measurement result of the resin film is F, and the corrected thickness of the water film is W ′, W ′ = (aF ² + bF + c) × W (where a, b ,
c is a constant).

The water film forming apparatus 10 adjusts the thickness of the water film based on the corrected measurement result of the water film thickness.
As the thickness of the water film used for the adjustment, an arbitrary value in the width direction of the resin film 2b was used. In addition, resin film 2b
The average value in the width direction, the average value of arbitrary plural points, the average value for each arbitrary section in the width direction of the resin film 2b, or the maximum value or the minimum value can be used. It is good to use properly. For example, the maximum value of the thickness of the water film is adjusted to a predetermined value when the film is slippery on the casting drum 1, and the minimum value of the water film thickness is adjusted under the condition that the film is not easily peeled off from the casting drum 1 and the film is easily broken. Is preferably adjusted to a predetermined value.

As a method of adjusting the thickness of the water film, for example, an adjustment may be made to eliminate the deviation between the relationship between the thickness of the water film and the measurement result of the thickness of the water film determined by the rotation speed of the casting drum 1. .

The resin film 2b formed into a sheet-like material in this manner is continuously wound up through a subsequent stretching step. In the stretching step, a sequential stretching method or a simultaneous biaxial stretching method can be used.

In the method for producing a resin film according to the present invention, the thickness of the water film interposed between the casting drum and the resin film is measured. The thickness of the water film relating to the adhesion between the resin film and the resin film can be measured. In addition, for example, the thickness of the water film can be measured without being affected by the scattering of the fine particles of water forming the water film. Furthermore, the thickness of the water film can be measured with high accuracy by correcting the measurement result of the thickness of the water film affected by the resin film by measuring the thickness of the resin film. That is, based on the corrected measurement result of the thickness of the water film, the thickness of the water film can be appropriately adjusted.

[0028]

EXAMPLES (Examples 1 and 2) Polyethylene terephthalate was melt-extruded and formed into a sheet using the apparatus shown in FIG. The water film forming apparatus 10 used an apparatus configuration for sending out the humid air, and the supply amount of the humid air to be sent out was controlled by a control valve to adjust the thickness of the water film. The water film measuring device 20 includes a polarization infrared moisture meter (Kurashiki Boseki Co., Ltd.)
Was used. As Example 1, FIG. 2 shows a relationship diagram between the water film thickness and the measurement result according to the present invention when the thickness of the resin film is 28 μm.

FIG. 3 shows the relationship between the thickness of the water film according to the present invention and the measurement results when the thickness of the resin film is 45 μm as Example 2.

According to the present invention, since the water film is interposed between the casting drum 1 and the resin film 2b, the water film has a layered shape. For this reason, the measurement interposed between the casting drum 1 and the resin film 2b is not affected by the scattering phenomenon due to the shape of the water film, and the correlation between the thickness of the water film and the measurement result is high. Therefore, it is possible to accurately measure the thickness of the water film.

(Comparative Example) FIG. 4 shows the relationship between the thickness of the water film and the measurement result according to the prior art in which the water film measurement device 20 is disposed between the resin supply device 2 and the water film formation device 10. . When the water film measuring device 20 is arranged at this measurement position, since only the thickness of the water film formed on the casting drum 1 is measured, the water film thickness is affected by the scattering phenomenon due to the fine water film shape. And the measurement results have a significantly lower correlation than Examples 1 and 2. For this reason, the measurement results cannot be practically used for process control or water film thickness control.

[0032]

According to the method and the apparatus for manufacturing a resin film of the present invention, the thickness of the water film on the casting drum can be accurately measured as described above, and the thickness of the water film is determined based on the measurement result. Can be adjusted appropriately. Therefore, according to the present invention, a high-quality film can be manufactured at high speed and stably.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an apparatus for manufacturing a resin film according to the present invention.

FIG. 2 is a diagram illustrating a relationship between a thickness of a water film and a measurement result according to an embodiment of the present invention.

FIG. 3 is a relationship diagram between a thickness of a water film and a measurement result according to one embodiment of the present invention.

FIG. 4 is a diagram illustrating a relationship between a thickness of a water film and a measurement result according to an example of the related art.

[Explanation of symbols]

 1: casting drum 2: resin supply device 2a: molten resin 2b: resin film 3: electrostatic application device 10: water film formation device 20: water film measurement device 21: linear guide 22: motor 23: cylinder

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F205 AA24 AG01 AP11 AR12 GA07 GB02 GC02 GC09 GE07 GF06 GF29 GN24

Claims (4)

[Claims] 1. A method for producing a resin film in which a molten resin is formed into a sheet on a casting drum, comprising a means for forming a water film on the surface, wherein the molten resin is interposed between the casting drum and the sheet. A method for producing a resin film, comprising forming the water film into a sheet while adjusting the thickness of the water film. 2. A method for measuring the thickness of a water film interposed between a casting drum and a sheet, measuring the thickness of the sheet, and measuring the thickness of the water film based on the measurement result of the thickness of the sheet. The method for producing a resin film according to claim 1, wherein the measurement result of the thickness is corrected. 3. The method for producing a resin film according to claim 2, wherein the thickness of the water film is adjusted based on the corrected measurement result of the thickness of the water film. 4. A method for producing a resin film, comprising forming a water film on the surface of a molten resin into a sheet on a casting drum, comprising: (a) a method of forming a film between the casting drum and the sheet; Measure the thickness of the water film interposed, (b) measure the thickness of the sheet-like material,
(c) correcting the measurement result of the water film thickness based on the measurement result of the thickness of the sheet-like material, and (d) adjusting the thickness of the water film based on the corrected measurement result of the water film thickness. A method for producing a resin film.