JP2022107149A - Film manufacturing method - Google Patents

Abstract

To provide a film manufacturing method that prevents uneven wear of nip rolls, suppresses meandering of a film body, and improves conveyance stability.SOLUTION: A film manufacturing method includes film body forming step A in which a polymer solution is discharged from a die 1 onto a support to form a film body, and step B in which the film body formed in the step A is stretched longitudinally using at least a pair of nip rolls 5a and 5b. At least one nip roll of the pair of nip rolls in the step B has grooving at an edge running position in a film body width direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a film for preventing uneven pressure of the nip due to uneven wear of the nip rolls and for stably transporting the film in a step of longitudinally stretching using a pair of nip rolls in the method for producing a film.

A film made of aromatic polyamide, aromatic polyimide, polyester or the like is generally produced by a solution film forming method or a melt film forming method. In the production of this film, a device is provided in which a polymer is cast from a base onto a support such as a drum or an endless belt to form a film, and a film body (film body) is vertically stretched from the film using a pair of nip rolls. , A transverse stretching machine that spreads in the width direction and a winding machine that winds the film as a product obtained by this transverse stretching machine into a roll shape are used.
The rolls used in the longitudinal stretching of these film bodies are made by processing a metal or plastic composite material into a cylindrical shape and coating it with plating, plastic resin, rubber, etc., according to the application. Finely polished ones are used. In particular, for the nip roll, at least one of the upper and lower nip rolls sandwiching the film body needs to be particularly considered for wear resistance, heat resistance, non-adhesiveness, surface smoothness, etc., and those made of silicone rubber are preferably used. ing.
However, since the widths of the upper and lower rolls sandwiching the membrane body (film body) of the nip rolls are equal and the total length of the nip roll width is longer than the width of the membrane body, when the membrane body (film body) is niped and stretched, the membrane body is stretched. Since the silicone rubber at the end portion wears, the abrasion resistance is improved by notching so that the diameter gradually decreases from the position corresponding to the end portion of the film body toward the roll end (Patent Documents 1 and 2). ..

Japanese Unexamined Patent Publication No. 8-108470 Japanese Unexamined Patent Publication No. 2012-143877

However, in the method described in the above patent document, the wear resistance is improved by notching the nip roll from the corresponding position of the film body end toward the roll end, but the film body (film body) meanders. In some cases, it does not return to the steady position, and there are problems that the transportability is deteriorated, wrinkles are generated, and the film is torn.

In view of the above-mentioned problems in the prior art, the present invention provides a method for producing a film, which prevents uneven wear of the nip roll, suppresses meandering of the film body (film body), and improves transport stability. Is.

The present invention for achieving the above object is a film body forming step A for forming a film body (film body) by discharging a polymer solution from a die onto a support, and a film body (film) formed in the step A. A method for producing a film, which comprises a step B of vertically stretching a body) using at least a pair of nip rolls, and in the pair of nip rolls of the step B, at least one of the nip rolls has a groove processing at an end traveling position in the film body width direction. And.

According to the method for producing a film of the present invention, the following effects are obtained.
That is, as will be described later, in a pair of nip rolls, at least one of the nip rolls has a groove at the end traveling position in the film body width direction to prevent uneven wear of the nip rolls and suppress meandering of the film body (film body). By doing so, it is possible to improve the transport stability at the same time.

It is the schematic for demonstrating the dry-wet film formation. It is a schematic diagram which shows one aspect of the nip roll in this invention.

The present invention comprises a film body forming step A in which a polymer solution is discharged from a die onto a support to form a film body (film body), and at least a pair of nip rolls of the film body (film body) formed in the step A. The present invention relates to a method for producing a film having a step B of longitudinally stretching using the above, and in the pair of nip rolls of the step B, at least one of the nip rolls has a groove processing at an end traveling position in the film body width direction.

Hereinafter, the method for producing the film of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example of a manufacturing apparatus for manufacturing the film of the present invention.
In FIG. 1, the polymer solution 2 is discharged from the die (base) 1 to the support (endless belt device) 4 installed in the dryer 3 to form the film body F (step A). The formed film body F is conveyed in the liquid stored in the longitudinal stretching machine 5 by a pair of nip rolls (upper nip roll 5a, lower nip roll 5b) provided in the atmosphere, and the solvent contained in the film body F is a liquid. It is extracted and removed inside. The film body F'discharged from the longitudinal stretching machine 5 is widened in the width direction by passing through the transverse stretching machine 6 after passing through a pair of nip rolls (upper nip roll 5a, lower nip roll 5b) provided in the atmosphere, and the winding machine. It is wound into a roll by 7.

As shown in FIG. 1, a nip roll (upper nip roll 5a, lower nip roll 5b) is arranged in the longitudinal stretching machine 5 in order to suppress meandering of the film during stretching or scrape off the solution. Of the pair of nip rolls, it is preferable that the upper nip roll 5a is a driven roll and the lower nip roll 5b is a driving roll because the effect of suppressing the meandering of the film and scraping off the solution is good.
As described above, the method for producing a film of the present invention includes a film body forming step A for forming a film body by discharging a polymer solution onto a support using, for example, an apparatus as shown in FIG. .. As the polymer solution, a solution containing an aromatic polyamide or an aromatic polyimide can be used as described later.
Further, as the support, a drum can be applied in addition to the endless belt as described above.

Hereinafter, in the method for producing a film of the present invention, the nip roll used in the step B in which the film body (film body) formed in the step A is vertically stretched using at least a pair of nip rolls will be described in detail.

The nip roll used in the step B has a groove processing at an end traveling position in the film body width direction. In the present invention, having groove processing at the end traveling position in the film body width direction means that when the die width is L and the distance from the center portion in the nip roll width direction to the groove processing start point is K. It means that the groove processing is performed so that K becomes 0.70 L / 2 or more. If the nip roll does not have grooving, wear of the nip roll cannot be suppressed. Further, even if the nip roll is grooved, if the groove is formed at a traveling position (for example, near the center in the film width direction) that is not the end in the film width direction, the occurrence of wrinkles in the film body can be suppressed. Can not.

The grooving start point of the nip roll of the present invention is 0.75 L / 2 or more L / 2 when the distance from the center in the width direction of the nip roll to the grooving start point is K when the die width is L. The following is preferable, and 0.8 L / 2 or more and 0.95 L / 2 or less are more preferable. The width L of the die is not particularly limited, but is preferably 0.5 m or more and 5 m or less, more preferably 3 m or less, and further preferably 2 m or less. By setting the grooving start point K to L / 2 or less, the film body is located inside the grooving portion, so that the pressing by the nip roll is stabilized, so that the meandering of the film body is suppressed and the transport stability is enhanced. Can be done. As a more preferable embodiment, when the film body (film body) formed in the step A passes through the pair of nip rolls having groove processing on at least one of them in the step B, the widthwise end portion of the film body (film body) Is located in the grooved portion of the nip roll. Since the nip roll has groove processing at the end position in the width direction of the film body (film body), it is possible to particularly improve the suppression of wear of the nip roll and the suppression of meandering of the film. Grooving may be performed at the end running position in the film width direction on one side of the nip roll, or at the running position at the end in the film body width direction on both sides, but wear of the nip roll is suppressed and fluttering of the film is suppressed. From the viewpoint of (transportability), it is preferable that the nip roll is provided for grooving at both end running positions in the film body width direction.

Further, it is preferable that the nip roll of the present invention does not have grooving in a region where the distance from the central portion in the width direction of the nip roll is larger than 0.95 L / 2. By not having groove processing in the region where the distance from the center in the width direction of the nip roll is larger than 0.95 L / 2, the pressing of the film edge is more stable, so that the meandering of the film body is suppressed and the transport is stable. Can be enhanced.

Further, the grooving may be performed on only one of the pair of nip rolls, or may be provided on both nip rolls. When it is provided in both nip rolls, it is preferable that the grooving positions overlap because the meandering of the film body is suppressed. From the viewpoint of suppressing the meandering of the film body, it is preferable that the groove processing is provided on one of the nip rolls.

When the nip roll of the present invention has the groove, the groove width is preferably 80 mm to 150 mm, more preferably 90 mm to 120 mm. When the groove width is 80 mm or more, the effect of suppressing the wear of the nip roll is obtained and it becomes easy, and when the groove width is 150 mm or less, it becomes easy to suppress the meandering of the film body, and problems such as film tearing occur. Occurrence can be suppressed.

When the nip roll of the present invention has the groove, the groove depth is preferably 0.5 mm to 1.5 mm, more preferably 0.8 mm to 1.2 m. By setting the groove depth to 0.5 mm or more, the effect of suppressing the wear of the nip roll can be highly obtained, and the effect of the groove can be sufficiently obtained because it comes into contact with the end portion of the film body. Further, by setting the groove depth to 1.5 mm or less, a high effect of suppressing the occurrence of wrinkles at the end portion of the film body can be obtained.

The roll diameter of the nip roll of the present invention is not particularly limited as long as it does not interfere with the effect of the present invention, but is preferably 50 mm to 400 mm, more preferably 100 mm to 300 mm, from the viewpoint of easy roll processing and extension of roll life. preferable.

In the nip roll of the present invention, it is preferable that at least one of the pair (two) nip rolls sandwiching the film is coated with a plastic resin or rubber on the surface. In particular, it is preferable that the surface of the core material portion is coated with rubber. In particular, it is preferable that the upper nip roll (driven roll) of the pair (two) nip rolls is formed by coating the surface of the core material portion with rubber, and the lower nip roll (driving roll) is a metal roll.

The material of the core material portion is not particularly limited as long as it does not interfere with the effect of the present invention, and examples thereof include stainless metal and fluororesin, and stainless metal and the like are particularly preferable from the viewpoint of chemical resistance and strength resistance. Examples of the rubber material include silicone rubber and fluororubber, and silicone rubber and the like are particularly preferable from the viewpoint of chemical resistance and wear resistance. The material of the metal roll is not particularly limited, and examples thereof include fluororesin, stainless metal, and silicone rubber, and stainless metal and the like are particularly preferable from the viewpoint of chemical resistance, wear resistance, and resistance to adhesion of dirt.

In the nip roll composed of the core material portion and the rubber portion, the core material diameter is not particularly limited, but is preferably 50 mm to 400 mm, more preferably 100 mm to 300 mm, from the viewpoint of easy processing and rubber replacement. The thickness of the coated rubber is not particularly limited, but is preferably 5 mm to 30 mm, more preferably 5 mm to 20 mm, from the viewpoint of easy rubber replacement and extension of roll life. Further, the ratio of the core material diameter to the rubber thickness is preferably (core material diameter) :( rubber thickness) = 4: 1 to 80: 1, and more preferably 4: 1 to 40: 1.

The rubber hardness (JIS K6253) of the rubber portion on the surface of the nip roll is preferably 30 degrees to 90 degrees, more preferably 60 degrees to 80 degrees. By setting the hardness to 90 degrees or less, it is possible to nip by utilizing the original function as rubber, that is, the elastic force, and it is possible to suppress the wear of the nip roll while suppressing the wrinkles of the film. Further, by setting the hardness to 30 degrees or more, it is possible to suppress the deformation of the rubber portion at the time of niping, suppress the occurrence of wrinkles of the film, and suppress the meandering of the film.

The shape of the nip roll of the present invention is not particularly limited, and examples thereof include a cylindrical shape and a shape having a groove at the end of the film body. In particular, the production method of the present invention can be particularly preferably used because a film body having a thin thickness and easily warping tends to meander during transportation, and the film is likely to be torn or wrinkled. The thickness of the film obtained by the production method of the present invention is not particularly limited, but is preferably used in the range of 1 μm to 25 μm, which is a thin film, and more preferably in the range of 2 μm to 20.0 μm.

Hereinafter, examples of the present invention will be shown, but the present invention is not limited to these examples.
The effect was evaluated by the following method.

(Evaluation method of transport status)
Regarding the conveyed state of the film, the meandering width of the film and the tearing of the film were evaluated according to the following evaluation criteria.
(meandeling)
◯: 5000 m of film is formed, the meandering width of the film is less than 30 mm Δ: 5000 m of film is formed, the meandering width of the film is less than 50 mm ×: 5000 m of film is formed, and the meandering width of the film is 50 mm or more (tear). )
◯: A film of 5000 m is formed, the number of times of film tearing is 0. Δ: A film of 5000 m is formed, the number of times of film tearing is 1 ×: A film of 5000 m is formed, and the number of times of film tearing is 2 times or more.

(Evaluation method of wear condition of nip roll)
Regarding the wear state of the nip roll, the state of the position where the nip roll passed through the end of the film body was confirmed and evaluated according to the following evaluation criteria.
◯: No wear on the nip roll Δ: Wear can be confirmed on the nip roll, but there is almost no damage to the film.
×: There is damage to the film due to wear of the nip roll.

(Example 1)
2-Chloro-p-phenylenediamine (hereinafter referred to as CPA) corresponding to 85 mol% as an aromatic diamine component and 15 mol% corresponding 4, A reaction solution was prepared by dissolving 4'-diaminodiphenyl ether (hereinafter referred to as DPE). Next, after adding colloidal silica to the reaction solution, 2-chloroterephthalic acid dichloride (hereinafter referred to as CTPC) corresponding to 98.4 mol% was added to the above reaction solution, and the polymerization tank jacket temperature was adjusted to -25. The polymerization reaction was started by keeping the temperature at ° C. As the solution temperature rises, the stirring speed is gradually reduced so that the temperature inside the polymerization tank can be maintained at 35 ° C. or lower, and the mixture is stirred for 2 hours to complete the polymerization reaction. After neutralization and completion of the entire process of producing aromatic polyamide, the solution was discharged over 150 minutes while keeping the jacket temperature at 70 ° C. to obtain 800 kg of aromatic polyamide solution.
The characteristics of the obtained aromatic polyamide solution were a polymer concentration of 10.5 wt%, a solution viscosity of 3,610 poise, and an intrinsic viscosity of ηinh2.59 dl / g.
After passing the above aromatic polyamide solution through a 5 μm cut filter, an endless belt having a diameter of 30 μm or more and a frequency of surface defects of 0.006 pieces / mm ² is used from the die using the manufacturing apparatus shown in FIG. The film was cast on a support) and heated with hot air at 160 ° C. for 1 minute to evaporate the solvent, and the self-retaining film was continuously peeled from the belt.

Next, the film body was introduced into the tank with a longitudinal stretching machine to remove the solvent and stretched 1.15 times in the longitudinal direction. As the nip roll, the distance K to the grooving start point of the nip roll was set to 0.85 L / 2 from the central portion in the width direction of the nip roll, and a nip roll having a groove width of 100 mm and a groove depth of 1.0 mm was used. For the pair (two) nip rolls, a metal roll was used for the drive roll to be the lower nip roll, and for the driven roll to be the upper nip roll, the surface of the core material was covered with rubber. For the groove processing on the roll, one of the pair (two) of the nip rolls at the inlet of step B, which is provided in the driven roll to be the lower nip roll, was used. Silicone rubber was used as the rubber material of the driven roll, and a roll having a rubber hardness of 70 degrees was used.
Then, the obtained film body was gripped by a clip of a transverse stretching machine to dry and heat-treat the moisture, stretched 1.4 times in the width direction, dried and heat-treated at 280 ° C. for 1 minute, and then dried and heat-treated. The film was slowly cooled at a rate of 20 ° C./sec to obtain a film having a thickness of 4 μm.

(Example 2)
In Example 1, the drying temperature on the belt was 145 ° C., the groove processing of the nip roll was performed in the same manner as in Example 1 except that the groove width was 120 mm, the groove depth was 0.8 mm, and the longitudinal stretching ratio was 1.05 times. A film having a film thickness of 2 μm was produced, but the productivity of the film was as good as that of a film having a film thickness of 4 μm. The results are shown in Table 1.

(Example 3)
In Example 1, except that the drying temperature on the belt is 180 ° C., the groove position is 1.00 L / 2, the groove width is 120 mm, the groove depth is 0.8 mm, and the longitudinal stretching ratio is 1.05 times. A film having a film thickness of 20 μm was produced in the same manner as in the above, but the productivity of the film was as good as that of a film having a film thickness of 4 μm. The results are shown in Table 1.

(Example 4)
In Example 1, a film having a film thickness of 4 μm was produced in the same manner as in Example 1 except that the groove width of the nip roll groove processing was 70 mm. The meandering of the film in the longitudinal stretching step was deteriorated, and as a result, the film could not be gripped by the clip of the transverse stretching machine in the next step, and the film was sometimes torn. The results are shown in Table 1.

(Example 5)
In Example 1, the same procedure as in Example 1 was carried out except that the groove width of the nip roll was grooved to be 160 mm, and a film having a thickness of 4 μm was produced. In the next step, the film could not be gripped by the clip of the transverse stretching machine, and the film was sometimes torn. The results are shown in Table 1.

(Example 6)
In Example 1, the same procedure as in Example 1 was carried out except that the groove depth for grooving the nip roll was 0.3 mm to produce a film having a thickness of 4 μm, but the meandering of the film in the longitudinal stretching step deteriorated. As a result, the film could not be gripped by the clip of the transverse stretching machine, which is the next step, and the film may be torn. The results are shown in Table 1.

(Example 7)
In Example 1, the same procedure as in Example 1 was carried out except that the groove depth for grooving the nip roll was 2.0 mm to produce a film having a thickness of 4 μm, but the meandering of the film in the longitudinal stretching step deteriorated. As a result, the film could not be gripped by the clip of the transverse stretching machine, which is the next step, and the film may be torn. The results are shown in Table 1.

(Example 8)
In Example 1, the same procedure as in Example 1 was carried out except that the distance to the grooving start point of the nip roll grooving was 0.70 L / 2, and a film having a thickness of 4 μm was produced, but in the longitudinal stretching step. The meandering of the film was exacerbated, and as a result, the film could not be gripped by the clip of the transverse stretching machine, which was the next step, and the film was sometimes torn. The results are shown in Table 1.

(Example 9)
In Example 1, a film having a thickness of 4 μm was produced in the same manner as in Example 1 except that the distance to the groove processing start point of the nip roll was 1.10 L / 2, but the film meandered in the longitudinal stretching step. As a result, the film could not be gripped by the clip of the transverse stretching machine, which is the next step, and the film may be torn. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, a film having a film thickness of 4 μm was produced in the same manner as in Example 1 except that the nip roll had no grooves. As a result, the film could not be gripped by the clip of the transverse stretching machine, which was the next step, and the film was torn and foreign matter was generated. The results are shown in Table 1.

(Comparative Example 2)
In Example 1, a film having a film thickness of 4 μm was produced in the same manner as in Example 1 except that a driven roll to be the lower nip roll having notch processing instead of groove processing was used. As the driven roll having the notch processing, the distance from the center of the roll to the notch processing start point was 0.85 L / 2, and the notch processing angle was set to 4 degrees. The meandering of the film deteriorated in the longitudinal stretching step and the nip roll was worn due to the meandering. As a result, the film could not be gripped by the clip of the transverse stretching machine in the next step, and the film was torn. The results are shown in Table 1.

1: Die (base)
2: Polymer solution film 3: Oven 4: Endless belt 5: Longitudinal stretching machine 5a, 5b: Pair of nip rolls 6: Horizontal stretching machine (tenter)
7: Winder

Claims (7)

A film body forming step A in which a polymer solution is discharged from a die onto a support to form a film body (film body), and a film body (film body) formed in the step A are vertically formed using at least a pair of nip rolls. A method for producing a film, which comprises a step B of stretching, and in the pair of nip rolls of the step B, at least one of the nip rolls has a groove processing at an end traveling position in the film body width direction. The method for producing a film according to claim 1, wherein the nip roll has a surface coated with a plastic resin or rubber. The width of the nip roll is wider than the width of the die.
When the width of the die is L (mm) and the distance from the center in the width direction of the nip roll to the grooving start point is K (mm).
0.75L / 2 ≤ K ≤ L / 2
The method for producing a film according to claim 1 or 2, which satisfies the above conditions. Grooving of the nip roll is 0.75 L / 2 ≤ K ≤ L / 2.
The method for producing a film according to any one of claims 1 to 3, which has only the range of. The method for producing a film according to any one of claims 1 to 4, wherein the groove width of the groove processing of the nip roll is 80 mm or more and 150 mm or less. The method for producing a film according to any one of claims 1 to 5, wherein the groove processing depth of the nip roll is 0.5 mm or more and 1.5 mm or less. The method for producing a film according to any one of claims 1 to 6, wherein the thickness of the film is 1 μm or more and 25 μm or less.

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