JP2003071783A - Method of cutting film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of cutting a film capable of increasing the film productivity by improving the cutting condition of a cut part of the film without generating deficiencies such as deterioration of flatness of the cut part. SOLUTION: In cutting a film 12, the residual volatile part of the film 12 is 1-15%, and the temperature of the cut part of the film 12 is 60 deg.C-TG (temperature of transition of polymer to glass). Therefore, the cut end surface in excellent cutting condition can be obtained, so that cutting waste is reduced, and moreover, as the temperature is less than the TG temperature, the flatness of the cut part can be secured. Accordingly, the film can be cut stably and in excellent cutting condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a film, and more particularly to a method for cutting a cellulose triacetate film used as a support for photographic light-sensitive materials.

[0002]

A film used as a support for a photographic light-sensitive material, for example, a film such as a cellulose triacetate film, is cast into a film form on a band or a drum from a casting die by a solution casting method. The film is formed by stripping the thin film from the band or drum. The formed film is wound on a take-up reel after drying the solvent. In addition, the film before being wound on the take-up reel was provided with various functions for improving chargeability, scratch resistance, dyeing, or improving adhesion with a photographic photosensitive emulsion layer to be applied in a later step. An organic solvent layer may be applied.

In the production of the above-mentioned film, the ears of the film (both ends in the width direction of the film) are subject to curl at the ears of the film because the thickness is likely to vary greatly due to unevenness in drying during drying or neck-in during casting. And loosening occurs. As a result, wrinkles are generated from the ears of the film during transportation, making it impossible to manufacture a stable film.

As a countermeasure against this, a cutting step is usually provided during the process from film formation to winding, in which the edge portion of the film is continuously cut and removed along the transport direction of the film. Further, just before the film is taken up on the take-up reel, a cutting process for cutting and removing the edge portion of the film again is provided in order to accurately manage and maintain the width of the film as a product. In these cutting steps, if the cut portion of the film is not cut well, cutting dust such as film powder or fibrous film is generated, and the cutting dust adheres to the cutting blade or the end surface of the cut film. Then, the cutting waste adheres to the surface of the film due to vibration, static electricity, wind, and the like during the transport of the film. When a photographic photosensitive emulsion is applied to the surface of a film to which cutting scraps are attached, the photosensitive emulsion layer becomes uneven, and it cannot be used as a product, resulting in product loss. Further, if the cutting quality of the cut portion of the film further decreases, cracks may occur in the film during cutting, and the cracks may cause breakage in the entire width direction of the film.

In order to prevent these troubles, it is important that the cutting condition of the cut portion of the film is always in the best condition, but in reality, the cutting blade is frequently replaced with a new one. is doing.

However, the frequent replacement of the cutting blade requires a great deal of cost, and the time required for the replacement causes a reduction in production efficiency. Further, it is a fact that the measure of frequently changing the cutting blade does not always give a sufficient effect and does not fundamentally improve the method of cutting the film.

As a countermeasure, Japanese Unexamined Patent Publication No. 1-281896 discloses heating a cut portion of a film to a temperature of TG (polymer glass transition temperature) to TG + 100 ° C. and cutting the cut portion with a cutter or the like. .

[0008]

However, as in Japanese Patent Laid-Open No. 1-281896, when the temperature of the cut portion of the film is heated to TG temperature or higher, the cutting condition of the cut portion is improved, but the periphery of the cut portion is improved. Has a corrugated shape like wakame, and the flatness of the film is deteriorated. As a result, problems such as wrinkles occurring in the film in the subsequent conveying step and winding deviation (a state in which the side surface of the web roll becomes uneven) occur when the film is wound around the winding roller. There is.

In the vicinity of the cut portion of the cut film (both ends of the cut film), the flatness is deteriorated, so that the product becomes an ineligible portion and the portion must be cut again. It causes a great product loss.

Further, when the cellulose triacetate film coated with the above-mentioned organic solvent layer is cut,
When heated above TG, the components in the coating solution are strongly bound to cellulose triacetate and cannot be separated. As a result,
There is a problem that it becomes impossible to reuse the cut film ears and the amount of waste increases.

The present invention has been made in view of the above circumstances, and improves the cutting condition of the cut portion of the film so as to prevent problems such as reduction in flatness of the cut portion.
It is an object of the present invention to propose a film cutting method capable of increasing film productivity.

[0012]

In order to achieve the above-mentioned object, the present invention is a method of transporting a film edge portion in the process of casting to winding in a step of producing a film by a solution casting method. It is characterized in that a step of continuously cutting and removing along is provided. As a result, a stable film is produced by preventing wrinkles from being generated from the ears of the film during transportation.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the film cutting method according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an example of a film cutting device to which the film cutting method according to the present invention is applied.

As shown in FIG. 1, a film cutting device 10
Mainly includes a transport device 14 for transporting the film 12,
A pair of rotary cutting blades 16 and 16 respectively arranged at the cutting positions of the ears 12A in the width direction of the film 12, and a pair of heaters 18 and 1 for heating the cut portion of the film 12.
8 and.

The transport device 14 has a pair of pinch rollers 14A, 14 that rotate by holding the film 12 from above and below.
A and a plurality of guide rollers 14B for guiding the conveyance of the film 12, and the film 12 is indicated by an arrow 13 in the figure.
Transport in the direction.

The rotary cutting blade 16 is composed of an upper rotary cutting blade 16A and a lower rotary cutting blade 16A. The two rotary cutting blades 16A and 16A sandwich the film 12 from above and below. The cut portion of the film is continuously cut by rotating in the film transport direction.

The heaters 18 are arranged at the cutting positions of the ears 12A in the width direction of the film 12, and
High-temperature hot air is blown onto the cut portion of the film 12 to heat the cut portion.

Then, the film cutting device 1 having the above structure
In order to carry out the film cutting method of the present invention by using 0, the drying conditions and humidity control conditions are adjusted in the drying step (not shown) before cutting to adjust the residual volatile content to 1% to 15% in advance. The formed film 12 is conveyed to the rotary cutting blade 16 by the conveying device 14. Immediately before the film is conveyed to the rotary cutting blade 16, the temperature of the cutting portion of the film 12 is raised to 60 ° C. to TG (glass transition temperature of the polymer) by the heater 18, and in this state, the film cutting edge is heated. The portion 12A is cut with a rotary cutting blade.

From the point of view of improving the cutting property for improving the cutting condition of the cut part of the film 12, the temperature of the cut part of the film at the time of cutting is preferably TG (polymer glass transition temperature) or higher. However, when the temperature of the cut portion of the film 12 is heated to TG or higher, the cut portion is thermally deformed and the flatness in the vicinity of the cut portion is deteriorated, which is preferable from the viewpoint of the quality of the film 12 or the product yield. Absent. Therefore, it is important to keep the temperature of the cut portion of the film 12 below TG.
When it is less than G, reduction in cutting property cannot be avoided.

Therefore, in the method of cutting a film according to the present invention, the residual volatile content of the film 12 at the time of cutting and the temperature of the cut portion of the film 12 are appropriately maintained and cut, and the cut portion of the film 12 is cut. It is intended to satisfy both "improvement of cutting property" and "securing of flatness".

That is, as a result of diligent examination by the inventor of the present invention through experiments and the like regarding "improvement of cutting property" and "securing of flatness" in the cutting part of the film 12, residual volatile components (water + solvent) contained in the film at the time of cutting It has been found that, when the temperature of the cut portion of the film 12 is less than TG, a cut end surface having a good cutting condition can be obtained and a cutting with a very small amount of cutting scraps can be performed by setting the above value to a certain value or more. T
The reason why the cut end surface having a good cutting condition is obtained even if it is less than G is that the residual volatile content contained in the film 12 is set to a certain level or more, so that the cut portion can be appropriately softened even by heating below TG. It is considered to prevent brittle fracture of the cut portion during cutting.

Further, when the relationship between the residual volatile content and the temperature of the cut portion was investigated, the temperature of the cut portion tended to soften the cut portion of the film 12 even if the temperature of the cut portion of the film 12 was lower, as the residual volatile content increased. However, 60 ° C. or higher is necessary to secure appropriate softening for “improving cutting property”. On the other hand, when the temperature of the cut portion is brought close to TG, the residual volatile content may be 1% or more.

Generally, the cutting on the upstream side of the film manufacturing process in which the residual volatile content is high at 30% or more, the film 12 is soft, and the problem of cutting scraps and cutting condition is not as serious as the cutting on the downstream side with a small residual volatile content. Absent. However, for example, when a large amount of a solvent having a low boiling point such as methylene chloride is contained as a residual volatile component, when the temperature of the cut portion reaches the boiling point of methylene chloride, foaming is likely to occur in the cut portion, which is stable. You cannot cut. Therefore, when the temperature of the cut portion is set to 60 ° C. or higher for ensuring proper softening for “improving the cutability”, the residual volatile content is 15% or less in order to prevent foaming of the film 12. Need to be kept to.

As described above, the residual volatile content of the film 12 and the temperature of the cut portion of the film 12 are not independent of each other, but it is necessary to set the conditions in association with each other.

According to the film cutting method of the present invention, the residual volatile content of the film 12 at the time of cutting is 1%.
The temperature of the cut portion of the film 12 was set to 60% to TG (glass transition temperature of the polymer), and the film 12 was cut. With this, since it is possible to obtain a cutting end surface having a good cutting condition, there is no problem of cutting waste,
Moreover, since the temperature is lower than the TG temperature, the flatness of the cut portion can be secured. Therefore, it is possible to perform stable cutting with a good cutting condition.

In the cutting of the film edge portion immediately before winding the film 12 in order to obtain a strictly defined film width, if the residual volatile content is too much, the film 12 may change with time after winding. The flatness is deteriorated, and the photographic property when used as a material for a photographic photosensitive material is likely to change. Therefore, in such a case, the film 12
It is more preferable to maintain the residual volatile content of 1 to 5% and the temperature of the cut portion of the film at 80 ° C to TG.

In the present invention, heating with hot air can be performed from both sides, and it is also preferable to direct the air from the inside to the outside from the viewpoint of film deformation.

In the embodiment of the present invention, an example in which the cut portion of the film is heated by the heater has been described, but heating by far infrared rays or the like is also possible, and it is also possible to heat the cutting blade itself. . In this case, since the contact time between the film 12 and the cutting blade is short, it is necessary to lengthen the contact time between the film and the cutting blade so that the cut portion of the film can be heated to a predetermined temperature.

[0030]

[Examples] Examples performed using the film cutting apparatus 10 described in the present embodiment will be described below.

The type of film, the condition of residual volatile content of the film, and the temperature condition of the cut portion in this example are as follows. (1) Type of film: gelatin, methylene chloride,
200 μm thick cellulose triacetate film coated with an organic solvent layer consisting of methanol and acetone (2) Conveyance speed of film: 10 m / min (3) Residual volatile content of the film during cutting: 1.9%
(Component composition: water content 0.9%, butanol 0.8%, acetone 0.1%, methylene chloride 0.1%) (4) Temperature of the cut portion of the film at the time of cutting ... 70 °
C (measured with a radiation thermometer) In Comparative Example 1, only the temperature of the film at the time of cutting was 26 ° C.
(Room temperature), and other conditions were the same as in the example.

In Comparative Example 2, the residual volatile content of the film was reduced to 0.
9, and other conditions were the same as in the example.

In Comparative Example 3, only the temperature of the film at the time of cutting was 115 ° C., which was 10 ° C. higher than 105 ° C. which is the TG temperature of the cellulose triacetate film, and the other conditions were the same as those of the example.

The judgment was made at two points, "improvement of cuttability" and "securing of flatness", and the quality of cuttability was judged by observing the ratio of the cut area and the cut area of the cut end face with a microscope. . That is, the cutting region is a portion actually cut by the cutting blade, and the breaking region is a portion apparently cut by the crack of the film during cutting. Therefore, a large number of fractured areas means that a large amount of cutting waste is generated.

As a result, in the present embodiment, continuous cutting was carried out for 48 hours without exchanging the cutting blade, but as shown in FIG. 2 (a), the cutting area was larger than the breaking area and the cutting condition was good. The cut end face was obtained, and the generation of cutting waste was extremely small. Further, the flatness of the cut portion can be ensured, and it is not necessary to cut the film edge portion again, so that the product yield can be improved. Further, the cut film ears can be sufficiently reused, and the production cost can be reduced.

On the other hand, in Comparative Example 1, although the flatness was ensured, as shown in FIG. 2B, the cutting area was much smaller than the breaking area and the cutting quality was poor. As a result, cutting waste adhered to the cut end surface immediately after the start of cutting, and further, the cutting waste was found to adhere to the film surface in the vicinity of the cut portion, resulting in a large product loss. Further, because the cutting quality was poor, the cutting blade had to be frequently cleaned, and the cutting blade had to be replaced 12 hours after the start of cutting.

As shown in FIG. 2 (c), Comparative Example 2 was slightly better than Comparative Example 1 in cutting quality, but was inferior to this Example. As a result, it was necessary to clean the cutting blade 12 hours after the start of cutting and replace the cutting blade 24 hours later. Further, although the generation of cutting chips was less than that of Comparative Example 1, the cutting chips were considerably attached to the cutting end face.

In Comparative Example 3, the temperature of the cut portion was made higher than the TG temperature, and the cutting condition was about the same as that of the present embodiment shown in FIG. 2A, but the film surface near the cut portion was The corrugation became wakame and the flatness decreased. As a result, the vicinity of the cut portion did not become a product and it was necessary to cut again, resulting in a significant product loss.

From the above results, when the effects of the film cutting method of the present invention are summarized, the generation of cutting scraps during cutting is reduced, and it is almost impossible to use the product as a product due to the cutting scraps. Since the flatness of the cut portion of the film could be ensured, the trouble of cutting the entire film, the trouble of transport, etc. due to the flatness disappeared. Since the cutting condition of the cut portion of the film is improved and stable cutting can be performed, the life of the cutting blade is extended and the frequency of exchanging the cutting blade is greatly reduced. In addition, since the amount of cutting waste was greatly reduced, the frequency of cleaning around the cutting blade and the cutting device was also greatly reduced. By the way, the replacement frequency and the cleaning frequency of the cutting blade are about ⅕ of those of the comparative examples 1 and 2 described above.
Became.

In this embodiment, the cellulose triacetate film has been described as an example, but the invention is not limited to this.

[0041]

As described above, according to the film cutting method of the present invention, the residual volatile content of the film during cutting and the temperature of the cut portion of the film are within a predetermined range (for example, the residual volatile content is 1%). ~ 15%, cutting temperature is 60
Since the cutting is performed in a state of being maintained at (° C to TG), a cutting end surface with a good cutting condition can be obtained, and there is no problem of cutting waste, and a stable cutting with a good cutting condition can be performed. it can. Moreover, since the temperature is lower than the TG temperature, the flatness of the cut portion can be secured, and the product loss is reduced.

Therefore, by adopting the cutting method of the present invention, the productivity in film production can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus for applying a film cutting method according to the present invention.

FIG. 2 is an explanatory view for explaining the cutting condition of the cut end surface of the film, and FIG. 2 (a) shows the case of the present embodiment.
2B shows the case of Comparative Example 1, and FIG. 2C shows the case of Comparative Example 2.

[Explanation of symbols]

10 ... Film cutting device, 12 ... Film, 12A ...
Film ears, 14 ... Conveying device, 16 ... Rotary cutting blade, 18 ... Heater

Claims (3)

[Claims] 1. In the step of producing a film by a solution casting method, a step of continuously cutting and removing the edge portion of the film along the method of transporting the film is provided during casting and winding. A method for cutting a film, which comprises: 2. The method of cutting a film according to claim 1, wherein the step of cutting and removing the edge portion of the film is performed immediately after winding after the completion of the drying step. 3. The method of cutting a film according to claim 1, wherein the film is cellulose triacetate.