JPH09309137A - Method and device for manufacturing organic polymer film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable removal of adhered materials on a cap without discontinuing the manufacture by molding an organic polymer into the film shape while removing the adhered materials in the vicinity of a slit of the cap. SOLUTION: When an organic polymer is extruded from a cap to manufacture a film, the organic polymer is molded into the film shape while removing adhered materials in the vicinity of a slit of the cap. For the purpose of removing the adhered materials, a process of hydrolyzing the adhered materials, a photodissociation process, a decomposition process by using heat and elasticity, a chemical decomposition process or the like is used. To be concrete, a process of providing the humidity in the periphery on the vicinity of a slit section of a cap of preferably to 0.007-0.1kg/kg' by using humidified air, a process of emitting ultraviolet rays of wave length of preferably 300nm or under in the vicinity of the slit of the cap, a process of decomposing electrically or thermally the adhered materials in the vicinity of the slit of the cap by using corona discharge, a thermal decomposition process or a process of spraying ozones in the vicinity of the slit section of the cap can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing an organic polymer film, particularly an aromatic polyester film, used as a base material for magnetic recording media, packaging materials, ink ribbons, prepaid cards and the like. is there.

[0002]

2. Description of the Related Art When an organic polymer such as an aromatic polyester is formed into a film, a so-called "eye area" is formed in the vicinity of a mouth slit portion which is a discharge hole of the organic polymer.
Accumulation of deposits called "," etc., accumulates on the film, causing local unevenness in the thickness of the film. Conventionally, the only method for removing the deposits is to physically scrape off the deposits. Therefore, there is no choice but to temporarily suspend the production of the film, which causes a problem of production loss. In order to improve it, for example, as disclosed in Japanese Patent Laid-Open No. 4-299115 or the like, a method of improving the material of the die slit portion itself, or as disclosed in Japanese Patent Laid-Open No. 63-312347. , A method of adding an antioxidant or the like into an organic polymer has been proposed.

[0003]

However, any of the above means is a method for suppressing the generation or adhesion of deposits, and once the deposits adhere to the vicinity of the die slit portion, the production is temporarily suspended. Therefore, it is necessary to scrape off the adhering substances, which is also a manufacturing loss, and therefore it is necessary to improve it.

An object of the present invention is to pay attention to such a problem, and a method for producing an organic polymer film capable of removing deposits on a die without interrupting production, that is, without causing production loss, and To provide a manufacturing apparatus.

[0005]

In order to solve the above-mentioned problems, the method for producing an organic polymer film of the present invention is a method for producing a film by extruding an organic polymer through a die, wherein the slit of the die is used. The method is characterized in that the organic polymer is formed into a film while removing deposits near the portion.

Further, the apparatus for producing an organic polymer film of the present invention is characterized by comprising an adhering substance removing device for adhering substances in the vicinity of the slit portion of the die while discharging the polymer from the die. Consists of.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The organic polymer of the present invention includes polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene α, β-bis (2-chlorophenoxy) ethane 4,4-dicarboxylate, poly Aromatic polyesters such as butylene terephthalate, aromatic polyamides or polyimides, polyolefins such as polyethylene and polypropylene are used, but aromatic polyesters are preferred, and polyethylene terephthalate is particularly preferred. Here, “mainly” means that the aromatic polyester contains 70 mol% or more. The aromatic polyester may be a homopolyester or a copolyester, or may be a mixture of other components in a proportion of less than 30 mol%.

The organic polymer of the present invention may be added with a lubricant, an antioxidant, an antistatic agent and other additives to the extent that the characteristics of the base film are not impaired.

The film of the present invention may be a single layer film or a composite film composed of two or more layers.

In the organic polymer film of the present invention, it is necessary to mold the organic polymer into a film while removing the deposits in the vicinity of the slit portion of the die. That is, the deposit is removed while the polymer is discharged from the die. Since the vicinity of the slit part of the die is in contact with or is thin with the molten organic polymer, part of the organic polymer and its metamorphic substances, etc. are deposited to form an adhered substance, which is not solidified immediately after discharge. Since the organic polymer film in a state may have irregularities, and as a result, may cause a streak of the base, the deposit is removed.

The term "adhered matter" as used herein refers to the cause of the streak of the die, so that not only those that are attached in the vicinity of the slit portion of the die, but also those that come out from the organic polymer or sublimate Includes all that may be attached near the slit. In addition, here, "removal" is intended to eliminate and reduce the streak of the base, so a method of scraping off the adhered matter from the vicinity of the slit part of the base or a method of disassembling the adhered matter and removing it from the vicinity of the slit part of the base Of course, a method of reducing the viscosity and hardness of the deposit to reduce the unevenness of the organic polymer film immediately after ejection is also included. Note that the vicinity of the slit portion of the die is the slit portion itself which is a discharge hole,
And a portion within a distance of 10 mm from the outer circumference of the slit portion. Further, "while removing" refers to a state in which the production of the film is temporarily interrupted and the deposit is removed after forcibly breaking the film, or the production of the film is interrupted as a result of the removal of the deposit. Not a thing. That is, it means that the removal of the deposit and the production of the film can be carried out at the same time without causing the film to break due to the removal of the deposit.

The method of removing the deposits of the present invention is preferably a method of being substantially non-contact with the organic polymer discharged from the die. That is, if the method of removing the deposits is not substantially non-contact, the entire or part of the removing device contacts the organic polymer discharged from the die when removing the deposits, and the film thickness This is because unevenness and film breakage may occur, resulting in interruption of film production. Examples of the method for removing the deposits without substantially contacting the organic polymer discharged from the die include a method of hydrolyzing the deposits, a method of photodegrading, a method of decomposing with heat or electricity, and a chemical reaction. It is possible to use a method of decomposing by. That is, since the adhered matter is mainly composed of the organic polymer itself and / or its modified substance forming the film, the adhered matter and the organic polymer film are directly contacted by using the above-mentioned removal method. This is because the deposit can be decomposed, the viscosity can be reduced, or the hardness can be reduced without doing so. Specifically, using humidified air, the humidity around the slit portion of the die is adjusted to 0.005.
~ 0.5 kg / kg ', preferably 0.007-0.
1 kg / kg ', a method of irradiating a short wavelength light of 400 nm or less, preferably an ultraviolet ray of 350 nm or less, more preferably an ultraviolet ray of 300 nm or less to the vicinity of the slit portion of the die, using corona discharge A method of electrically or thermally decomposing the deposits in the vicinity of the slit portion of the die, a method of spraying or filling an active gas such as ozone in the vicinity of the slit portion of the die, or a method using a combination thereof Among them, the method using humidified air, ultraviolet rays, or a combination thereof is practical and particularly preferable.

For the above reasons, the film manufacturing apparatus of the present invention must be equipped with a device for removing deposits in the vicinity of the slit portion of the die.
It is preferable that the apparatus removes the deposits by a method that is substantially non-contact with the organic polymer discharged from the die. Specific examples of the removing device include a humidifying device such as a steam or a humidifier, a black light, an ultraviolet irradiation device such as a mercury lamp or a mercury-xenon lamp, a corona discharge device, and an active gas generating device such as ozone. A combination can be used. The adhering matter removing device may be directly installed in the manufacturing device, or may be a portable device that is attached as needed.

Since the deposits of the present invention do not interfere with the production of the film, they may be removed from the beginning of production or after the production of the streak.

Next, regarding the method for producing the film of the present invention,
An aromatic polyester film will be described as an example,
It is not limited to this.

First, polyester is polymerized by a conventional method to obtain polyester pellets. At this time, particles may be appropriately added using a particle addition method. The polyester pellets are sufficiently dried and formed into a film by a known melting method, extrusion method or casting method. Incidentally, the vicinity of the slit portion of the die, at least one selected from the method of humidifying the periphery with humidified air, irradiating with ultraviolet rays, using corona discharge, blowing active gas, or filling active gas, or A combination of two or more kinds is carried out from the beginning of manufacturing to the beginning or at the time when a base line is generated. A known stretching method and heat treatment method may be added to the unstretched film thus obtained, if necessary.

[Characteristic Measuring Method] The characteristic values of the present invention are based on the following measuring methods and evaluation criteria. (1) Judgment of base streak The unstretched film obtained by casting was visually observed at a position immediately before the stretching in the longitudinal direction, and the presence or absence of a streak of the base was investigated and evaluated in the following three stages. . ⊚: No occurrence of base streak is observed. Δ: A slight streak is generated. X: Severe base line is generated. Regarding the strength of the spinneret, a film after stretching in the longitudinal direction and the width direction was sampled, and the thickness in the width direction of the film was measured with an electronic micrometer (FI manufactured by Anritsu Corporation).
LM THICKNESS TESTER KG601A), the film obtained by continuously running the film under the following measurement conditions was measured. From the chart obtained, "strength" was 0.5 μm when the displacement of the thickness of the die streak was 0.5 μm or more. Less than was defined as "mild".・ Measurement conditions Film take-up speed: 1.5 m / min, chart speed:
60 cm / min

(2) Humidity of the atmosphere in the vicinity of the slit portion of the die The humidity at a location not in contact with the die, film and cooling drum at a distance of 40 mm from the slit portion of the die is the high temperature humidity manufactured by Yokogawa Electric Corporation. The absolute humidity obtained by measurement using a detector ZH8D was used as the humidity of the atmosphere in the vicinity of the slit portion of the die.

[0019]

The present invention will be described in more detail based on the following examples. Table 1 shows the evaluation results. Example 1 Polyethylene terephthalate containing 0.2% by weight of dry silica having an average particle size of 1 μm was melt extruded at 280 ° C. and 280
The film was discharged from the slit portion of the die at a temperature of ℃ and cast on a cooling drum to produce an unstretched film. The gap in the slit portion of the die at this time was 2 mm, and the humidity around the slit portion of the die was 0.004 kg / kg '.

Immediately after the melted polyester was ejected from the slit portion of the die, ultraviolet irradiation was started in the vicinity of the slit portion of the die by an ultraviolet irradiation device, and it was used until the end of production. The UV irradiation device is Hamamatsu Photonics KK
A UV spot light source L2859-01 manufactured by Mitsui Chemicals, Inc. was used. The distance from the irradiation part of the ultraviolet irradiation device to the slit part of the die was 100 mm, and one unit was installed with respect to the die width of 50 mm.

The resulting unstretched film was stretched in the longitudinal direction by 10
The film was sequentially stretched 3 times at 0 ° C. and 4 times at 100 ° C. in the width direction, and after the stretching was finished, heat treatment was performed at 200 ° C. for 10 seconds with a stenter to produce a biaxially stretched polyester film having a thickness of 10 μm.

Observation of the above-mentioned unstretched film revealed that no die streak was formed until 72 hours after the start of production. In addition, although the streak was generated after 96 hours, it was extremely slight.

Example 2 In the method of Example 1, instead of using the ultraviolet irradiation device, an ultrasonic humidifier was used to irradiate humidified air to the slit portion of the mouthpiece to reduce the humidity around the slit portion to 0. 0
The present invention was carried out in the same manner as in Example 1 except that the amount was set to 07 kg / kg '. After 48 hours had passed, there was a generation of a streak, but it was extremely slight, so that the production could be continued for 96 hours or more.

Example 3 In the method of Example 1, in addition to the use of an ultraviolet irradiation device, an ultrasonic humidifier was used to irradiate humidified air to the slit portion of the mouthpiece to reduce the humidity around the slit portion to 0. 007
The present invention was carried out in the same manner as in Example 1 except that kg / kg 'was used. Even after 96 hours or more, there was no occurrence of a stripe of the base.

Comparative Example 1 The present invention was carried out in the same manner as in Example 1 except that the ultraviolet irradiation device was not used. After 48 hours from the start of film formation, a severe die streak was generated on the film.

[0026]

[Table 1]

[0027]

As described above, according to the method and apparatus for producing an organic polymer film of the present invention,
It is possible to continuously and stably produce a desired film without generating a die streak and without interrupting the production due to a countermeasure for the die streak. Since no production loss occurs due to the countermeasure for the cap streak, productivity and yield can be improved.

Claims (7)

[Claims] 1. A method for producing a film by extruding an organic polymer from a die, wherein the organic polymer is formed into a film while removing deposits in the vicinity of the slit portion of the die. Method for producing organic polymer film. 2. The method for producing an organic polymer film according to claim 1, wherein the organic polymer mainly comprises an aromatic polyester. 3. The method for producing an organic polymer film according to claim 1, wherein the deposit is removed substantially without contact with the organic polymer discharged from the die. Method. 4. The removal of deposits is performed by using at least one kind selected from humidified air, ultraviolet rays, corona discharge and active gas, or a combination of two or more kinds. A method for producing an organic polymer film according to any one of 1. 5. An apparatus for producing an organic polymer film, comprising an adhering matter removing device for removing adhering matter in the vicinity of the slit portion of the die while discharging the polymer from the die. 6. The organic polymer film according to claim 5, wherein the deposit removing device is a device for removing deposits without contacting the organic polymer discharged from the die. Manufacturing equipment. 7. The adhering substance removing device is a device composed of at least one kind or a combination of two or more kinds selected from a humidifying device, an ultraviolet irradiation device, a corona discharge device, and an active gas generating device. Claim 5 or 6
The apparatus for producing an organic polymer film described in 1.