JPH08244110A - Biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film and method for producing the same - Google Patents

Abstract

(57) [Summary] [Structure] A biaxially oriented polyester film containing polyethylene-2,6-naphthalenedicarboxylate as a main component, characterized by having a crystallinity of 40% or more. Axial oriented polyethylene-2,6-naphthalene dicarboxylate film. [Effect] Output characteristics, thermal dimensional stability, dropout,
Biaxially oriented polyethylene-2,6-, which is suitable as a base film for magnetic tape and the like, which has excellent edge damage resistance.
Naphthalene dicarboxylate film and method for producing the same.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film and a method for producing the same.

[0002]

Polyesters, especially polyethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate and polyesters based on these, have excellent physical and chemical properties. It is widely used as a film or sheet and also as a molded product thereof.

In particular, polyester films are excellent in heat resistance, chemical resistance, and mechanical properties, so that many of them are used for magnetic tape, bottles, electricity, photography, packaging, drawing, etc. It is used for purposes.

On the other hand, downsizing of these application products,
In accordance with the needs for higher density, higher quality, etc., the required characteristics for polyester films are becoming more and more severe. Among the above applications, especially for magnetic recording medium applications, in addition to high quality, long-time recording, further high elastic modulus for base film thinning accompanying compact size,
Higher strength is desired.

When the elastic modulus of the base film is insufficient, the tension received from the magnetic head and guide pins during running causes
The magnetic tape is stretched, which adversely affects the electromagnetic conversion characteristics (output characteristics). In the magnetic tape for long-term recording, it is necessary to improve the elastic modulus in at least one direction because the base film is thinned. Therefore, as a polyethylene terephthalate oriented body, a base material of a magnetic recording medium and a flexible circuit board, which define crystallinity, crystal size, crystal orientation coefficient, and are excellent in elastic modulus and thermal dimensional stability, are known. (For example, JP-A-63-153115).

However, in the above-mentioned polyethylene terephthalate oriented body, there is an improvement in obtaining a polyethylene terephthalate oriented body excellent in elastic modulus and thermal dimensional stability by simply stretching in a uniaxial direction and then heat-treating. It has only been done. Therefore, although the elastic modulus in the stretching direction is large, the elastic modulus in the direction perpendicular to the stretching direction is small, and in some cases, sufficient electromagnetic conversion characteristics cannot be obtained for magnetic recording medium applications. Further, there is a problem in that the heat treatment method is not industrial and that the heat treatment time is long. Further, in the polyethylene terephthalate oriented body, since the thermal dimensional stability in the stretching direction and the direction perpendicular thereto is greatly different,
There have been problems such as shrinkage when the magnetic layer is applied, the calendering process, or when the produced video tape or the like is dubbed to manufacture a soft tape. As a method for improving the thermal dimensional stability, the film is relatively loosely wound and heat-treated in a heating furnace as it is (for example, JP-A-58-9821).
No. 9), it is difficult to wrap a wide and long film loosely, and since an air layer exists between the films, heat conduction between the films is slow, and a roll-shaped film. There was a problem that it took time to raise the temperature of the whole.

In order to solve the above problems, the present invention makes a simple improvement by adding only an infrared irradiation device to the existing film forming equipment, and is excellent in thermal dimensional stability, output characteristics, and edge damage resistance. An object is to propose an axially oriented polyethylene-2,6-naphthalenedicarboxylate film and a method for producing the same.

[0008]

The biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film of the present invention for this purpose is mainly composed of polyethylene-2,6-naphthalenedicarboxylate. An axially oriented polyester film having a crystallinity of 40% or more.

The polyethylene-2,6-naphthalenedicarboxylate of the present invention means, for example, one having an ester bond obtained by condensation polymerization from ethylene glycol and 2,6-naphthalenedicarboxylic acid. Is the main subject. Two or more kinds of polymers may be mixed, or a copolymerized polymer may be used, as long as the object of the present invention is not impaired. Further, within a range that does not impair the object of the present invention, flame retardants, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, organic lubricants such as pigments, dyes, fatty acid esters, waxes, polysiloxanes, etc. An antifoaming agent or the like may be added to the extent that it is usually added.

Biaxially Oriented Polyethylene-2,6-of the Invention
The crystallinity of the naphthalene dicarboxylate film is
It is 40% or more, preferably 42% or more, and more preferably 45%. If the crystallinity is less than 40%, sufficient thermal dimensional stability and edge damage resistance cannot be obtained, and the tension received from the magnetic head and guide pins during running may cause
The edges of the magnetic tape are damaged or stretched, and dropouts frequently occur, which adversely affects the output characteristics.

The method of increasing the crystallinity to 40% or more is not particularly limited, but infrared rays are polyethylene-2,
A method of irradiating a 6-naphthalene dicarboxylate film to increase the crystallinity of the film by at least 2% or more is preferably used. The improvement in crystallinity due to infrared irradiation is preferably 4% or more, more preferably 6% or more. The infrared irradiation may be performed in any step of the film manufacturing process, but it is preferably performed in a winder step after heat treatment of the film or a slit step of slitting the film to the product width. Infrared irradiation is preferably performed by selectively irradiating infrared light having a wave number of 600 to 1600 cm ⁻¹ using an infrared lamp (for example, a halogen lamp), a carbon dioxide laser, or the like. The processing time is preferably 0.2 to 300 seconds.

Biaxially Oriented Polyethylene-2,6-of the Invention
The naphthalene dicarboxylate film has the following output characteristics:
Although not particularly limited in terms of edge damage resistance, the elastic modulus in at least one of the longitudinal direction and the width direction is 900 k.
g / mm ² or more, more preferably 1100 kg / mm ² or more, further preferably 1300
It is at least kg / mm ² .

Biaxially Oriented Polyethylene-2,6-of the Invention
The naphthalene dicarboxylate film is not particularly limited, but the number of surface coarse protrusions H3 is 10/100 cm ^2.
The number is preferably 7/100 cm ² or less, more preferably 4/100 cm ² or less. If the number of coarse surface protrusions exceeds 10/100 cm ² , dropouts frequently occur, and it is not possible to obtain sufficiently satisfactory output characteristics as a magnetic tape.

Biaxially oriented polyethylene-2,6-of the present invention
The intrinsic viscosity [η] of the naphthalene dicarboxylate film is not particularly limited, but is 0.6 to 3.0 (dl
/ G) is preferred. It is preferably 0.7 to 2.0, and particularly preferably 0.8 to 1.5. When [η] is 0.6 or less, sufficient elastic modulus and strength as a base film for a long-time recording magnetic tape cannot be obtained. On the other hand, when it is 3.0 or more, the melt viscosity is too high, so that the film cannot be stably formed due to factors such as non-uniform flow of the polymer in the T-die.

Biaxially oriented polyethylene of the present invention-2,6-
The naphthalene dicarboxylate film is not particularly limited, but preferably has a two-layer structure of A layer and B layer from the viewpoint of output characteristics. The thickness of the A layer is not particularly limited, but from the viewpoint of output characteristics, it is 0.01 to 3.0 μm, preferably 0.02 to 2.0 μm, and more preferably 0.
It is from 03 to 1.0 μm. In the case of the laminated constitution, at least the main component of the layer B is polyethylene-2,6-naphthalenedicarboxylate, and other layers are not particularly limited, but polyester is preferably exemplified. The polyester is not particularly limited, but a polymer containing polyethylene terephthalate as a main component or a polymer containing polyethylene-2,6-naphthalenedicarboxylate as a main component is preferable.

Biaxially Oriented Polyethylene-2,6-of the Invention
The layer A of the naphthalene dicarboxylate film is not particularly limited, but is 0.01 to 1.0 μ in view of output characteristics.
m, preferably 0.02 to 0.5 μm, more preferably 0.03 to 0.3 μm.
It is preferable to contain 3.0% by weight, preferably 0.02 to 2.0% by weight. The type of particles may be either inorganic particles or organic particles. The organic particles are not particularly limited, but crosslinked organic particles, particularly polydivinylbenzene particles, are preferable from the viewpoint of output characteristics. The polydivinylbenzene particles are mainly composed of divinylbenzene as a crosslinking component. Among them, divinylbenzene is preferably at least 51%, preferably at least 60%, more preferably at least 75% of the particle component. As other ingredients,
Although not particularly limited, examples thereof include non-crosslinking components such as ethylvinylbenzene and diethylbenzene. Further, silicone particles are also preferably exemplified. The silicone particles are preferably those containing a two-dimensionally crosslinked organopolysiloxane (CH ₃ Si O _3/2 ) as a main component. As other particles, the crystal form is α type, γ type, δ type, θ
Type, η type alumina, zirconia, silica, titanium oxide, and other agglomerated particles, or calcium carbonate, colloidal silica, titanium oxide, and other monodispersed particles can also be used by appropriate particle dispersion in a polymer. A plurality of these particles may be used in combination.

The relationship between the thickness t of the A layer and the particle diameter d of the particles contained in the A layer is not particularly limited, but 0.2d≤t≤10d, preferably 0.3d≤t≤5d, more preferably 0.3.
When d ≦ t ≦ 3d, the output characteristics are particularly good.

The particles constituting the film layer other than the A layer, that is, the polymer constituting the B layer may contain particles. In this case, the particle size is 0.05 to 1.0 μm, preferably 0.1.
It is preferable to contain particles selected from calcium carbonate, alumina, silica, titanium oxide, organic particles, carbon black and the like having a content of 1 to 0.5 μm and a content of 0.05 to 1.0% by weight.

Biaxially Oriented Polyethylene-2,6-of the Invention
The naphthalene dicarboxylate film is a film in which the above composition is biaxially oriented. A uniaxial or non-oriented film is not preferable because it lacks strength in the width direction. Part of the film in the thickness direction, for example, the orientation of polymer molecules near the surface layer is non-oriented or not uniaxially oriented,
That is, when the molecular orientation of the entire portion in the thickness direction is biaxial orientation, the output characteristics become even better. In particular, when the molecular orientation measured by an Abbe refractometer, a refractometer using a laser, a total reflection laser Raman method or the like is biaxial orientation on both the front surface and the back surface, the output characteristics are further improved.

Biaxially oriented polyethylene of the present invention-2,6-
Naphthalene dicarboxylate film, 100 ℃,
The heat shrinkage rate after 30 minutes of treatment is not particularly limited, but is 0.10% or less, preferably 0.07% or less, more preferably 0.04% or less from the viewpoint of output characteristics and dropout.

Biaxially oriented polyethylene-2,6-of the present invention
When the naphthalene dicarboxylate film is used for a magnetic recording medium, a back coat layer may be provided on the surface opposite to the surface on which the magnetic layer is provided, if necessary.

Biaxially oriented polyethylene-2,6-of the present invention
The naphthalene dicarboxylate film is preferably used as a polyester film for digital magnetic recording media. Further, it is also preferably used as a polyester film for a magnetic recording medium for HDTV (high definition television, high definition television of the Japan Broadcasting Corporation, etc.), which requires particularly high output. The biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film of the present invention is also used for data storage such as computers.

The thickness of the obtained film is not particularly limited, but it is usually 1 to 1 for a magnetic tape for long-term recording.
30 μm, preferably 3 to 20 μm, particularly preferably 4
˜15 μm is used.

Biaxially Oriented Polyethylene of the Invention-2,6-
The naphthalene dicarboxylate film is particularly effective for magnetic recording media applications, but it is also useful for photography, capacitors, packaging, drafting, etc. due to its excellent thermal dimensional stability. it can.

Next, the biaxially oriented polyethylene-2 of the present invention,
A preferable example of the method for producing the 6-naphthalene dicarboxylate film is shown and described, but the method is not limited thereto.

First, the polyethylene forming the film
As a method for incorporating particles into 2,6-naphthalenedicarboxylate, ethylene glycol, which is a diol component, is dispersed in the form of a slurry, and this ethylene glycol is mixed with a predetermined 2,6-naphthalenedicarboxylic acid component. Polymerization is preferred. In addition, an aqueous slurry of particles was directly added to a predetermined polyethylene-2,6-naphthalene dicarboxylate.
The method of mixing with the pellets and kneading with polyethylene-2,6-naphthalene dicarboxylate using a vented twin-screw kneading extruder is effective for further improving the effect of the present invention. As a method for adjusting the content of particles, it is effective to prepare a high-concentration master by the above method and dilute it with a polymer that does not substantially contain particles during film formation to adjust the content of particles. is there.

Next, pellets containing a predetermined amount of particles are dried, if necessary, and then fed to a known melt extruder,
Sheets are extruded from a slit die and cooled and solidified on a casting roll to prepare an unstretched film.
In the case of a laminated polyester film, 2 or 3
An unstretched film is made by laminating the polyester in the molten state using a twin extruder, two or three layer manifold or confluence block. In this case, the polymer channel containing the particles has a high precision filter, a static mixer,
The method of installing the gear pump is effective for further improving the effect of the present invention. Especially high-precision filter is 10
A filter having a filtration accuracy for removing particles having a size of μm or more with a probability of 95%, preferably 9 particles having a size of 5 μm or more.
It is particularly effective for the effect of the present invention that the filter has a filtration accuracy of removing 5% of probability, and more preferably a filter having a filtration accuracy of removing particles of 3 μm or more with 95% of probability.

Next, this unstretched film is biaxially stretched and biaxially oriented. As a stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. However, by using a sequential biaxial stretching method of first stretching in the longitudinal direction and then in the width direction, the stretching in the longitudinal direction is divided into three or more stages, and the longitudinal stretching temperature is 75 to 175 ° C, preferably 100 to 150 ° C. Total longitudinal stretching ratio 3.0-8.0 times, longitudinal stretching speed 5,000-50,0
It is preferably performed in the range of 00% / min. As a stretching method in the width direction, for example, a method using a tenter is preferable, the stretching temperature is 80 to 170 ° C., the stretching ratio in the width direction is 3.5 to 8.0 times larger than the longitudinal ratio, and the stretching speed in the width direction is 1,000 to 20, 0
It is preferably performed in the range of 00% / min. Further, if necessary, longitudinal re-stretching and lateral re-stretching are performed. In that case, as the stretching conditions, the stretching in the longitudinal direction is 90 to 180 ° C., the stretching ratio is 1.1 to 2.0 times, and the stretching method in the width direction is tenter.
Is preferably used, and the stretching temperature is 90 to 180 ° C., and the stretching ratio in the width direction is preferably 1.1 to 2.0.

Next, this biaxially oriented film is heat-treated and wound into a winder in a roll shape. In this case, the heat treatment temperature is 170 to 240 ° C., especially 180 to 220 ° C., and the time is 0.1.
A range of 5-60 seconds is preferred.

When the film is heat-treated and wound into a winder in a roll shape, an infrared lamp (for example, a halogen lamp) or a carbon dioxide (CO ₂ ) laser is used.
Infrared rays are radiated by using a laser represented by. The wave number of infrared rays irradiating the film is 600
It is preferable to perform a process of selectively irradiating infrared rays of ˜1600 cm ⁻¹ . The processing time is preferably in the range of 0.2 to 300 seconds. This treatment may be performed when the film is slit into the product width.

[Physical property measuring method and effect evaluating method] The characteristic value measuring method and effect evaluating method of the present invention are as follows.

(1) Intrinsic viscosity [η] After dissolving in an o-chlorophenol solvent, it was measured at 25 ° C.

(2) Elastic Modulus According to the method defined in JIS Z-1702,
25 using an Instron type tensile tester
It was measured at 65 ° C. and 65% RH.

(3) Average particle size of particles The cross section of the film was measured by using a transmission electron microscope (TEM).
Observe at a magnification of 0,000 times or more. Section thickness of TEM is about 1
It is set to 00 nm, and the location is changed to measure 100 fields or more.
The average particle size of the particles is an average value of equivalent circle equivalent diameters of monodisperse particles. The particle size of the particles is a weight average.

(4) Content of particles A solvent in which the polymer is dissolved but not the particles is selected is selected, the particles are centrifuged from the polymer, and the ratio (% by weight) to the total weight of the particles is taken as the particle content. In some cases, the combined use of infrared spectroscopy is also effective.

(5) Film Lamination Thickness Using a secondary ion mass spectrometer (SIMS), the element derived from the highest concentration of particles in the film in the depth range from the surface layer to 3000 nm and the carbon element of polyester. The concentration ratio (M ⁺ / C ⁻ ) of is defined as the particle concentration, and analysis is performed in the thickness direction from the surface to a depth of 3000 nm. In the surface layer, the particle concentration is low due to the interface of the surface, and the particle concentration increases as the distance from the surface increases. In the case of the film of the present invention, the particle concentration once reaching the maximum value starts to decrease again.
Based on this concentration distribution curve, the surface particle concentration is 1 / maximum
A depth of 2 (the depth is deeper than the maximum value) was obtained and used as the laminated thickness. The conditions are as follows.

Measuring device Secondary ion mass spectrometer (SIMS) ATOMI, Germany
KA Co. A-DIDA3000 Measurement conditions Primary ion species O ₂ ⁺ Primary ion acceleration voltage 12 kV Primary ion current 200 nA Raster area 400 μm □ Analysis area Gate 30% Measurement vacuum degree 6.0 × 10 ⁻⁹ Torr E -GUN 0.5kV-3.0A In addition, when the most contained particles in the depth range of 3000 nm from the surface layer are organic polymer particles, it is difficult to measure by SIMS, so XPS while etching from the surface layer.
(X-ray photoelectron spectroscopy), IR (infrared spectroscopy), etc. may be used to measure the same depth profile as above to determine the layer thickness, and the cross-sectional observation with an electron microscope or the like may be used to determine the state of change in particle concentration or the polymer. It is also possible to recognize the interface from the difference in contrast due to the difference in the above and obtain the laminated thickness. Furthermore, after peeling the laminated polymer, the laminated thickness can be obtained using a thin film step measuring machine.

(6) Orientation of film surface It was measured using an Abbe refractometer with sodium D line (589 nm) as a light source. Methylene iodide was used as the mount solution, and measurement was performed at 25 ° C. and 65% RH.

The biaxial orientation of the film is such that the refractive indices in the longitudinal, width and thickness directions are N1, N2 and N3, respectively.
The absolute value of (N1-N2) is 0.07 or less, and N3 /
One of the criteria is that [(N1 + N2) / 2] is 0.95 or less. Further, the refractive index may be measured using a laser type refractometer. Further, when the measurement is difficult by this method, the total reflection laser Raman method can be used.

(7) Number of rough surface protrusions H3 ^Two measurement surfaces (100 cm ² ) were superposed on each other and brought into close contact with each other by an electrostatic force (applied voltage of 5.4 kV). Caused by the interference of
The height of the coarse protrusions was determined from the ton ring, and the number of coarse protrusions having three or more rings was defined as H3. The light source is a halogen lamp.
A 64 nm hand pass filter was used.

(8) Crystallinity The film density was measured at 25 ° C. using a density gradient tube made of an aqueous sodium bromide solution. Regarding the density of the A layer, the density was measured with a film having only the A layer manufactured under the same conditions or with a sample obtained by scraping the A layer from a laminated film. Also,
When the scraping operation is difficult, a method capable of measuring the crystallization state of only the surface layer, for example, the total reflection Raman method, FT-I
The information obtained by the R method or the like can be read as density using a calibration curve.

The crystallinity (%) was calculated by the following formula.

[0043]

(Equation 1) Polyethylene-2,6-naphthalene doxycarboxylate Amorphous density 1.325 g / cm ³ Crystal density 1.407 g / cm ³ Polyethylene terephthalate Amorphous density 1.335 g / cm ³ Crystal density 1.455 g / cm ^Sought as ³ .

(9) Heat shrinkage ratio Measured according to the method specified in JIS C-2318. However, the holding time in the oven was set to 30 minutes.

(10) Dropout Evaluation in Magnetic Tape A magnetic coating composition having the following composition is applied to a film by a gravure roll, magnetically oriented, and dried. In addition, a small test calendar device (steel roll / nylon roll,
(5 stages), after calendering at a temperature of 70 ° C. and a linear pressure of 200 kg / cm, curing is performed at 70 ° C. for 48 hours. The above tape raw fabric was slit into 1/2 inch to prepare a pancake. A length of 250 m from this pancake was incorporated into a VTR cassette to obtain a VTR cassette tape.

(Composition of magnetic coating) Co-containing iron oxide (BET value 50 m ² / g): 100 parts by weight S-REC A (vinyl chloride / vinyl acetate copolymer manufactured by Sekisui Chemical Co., Ltd.): 10 parts by weight Nipporan 2304 ( Polyurethane elastomer made by Nippon Polyurethane): 10 parts by weight-Coronet L (Polyisocyanate made by Nippon Polyurethane): 5 parts by weight-Lecithin: 1 part by weight-Methyl ethyl ketone: 75 parts by weight-Toluene: 75 parts by weight-Carbon black : 2 parts by weight Lauric acid: 1.5 parts by weight Using a VTR for this tape, after recording a signal from a TV test signal generator (Shibasoku TG-7 / 1 type), 25
100 passes at 120 ° C and 50% RH (120 minutes x 100 passes)
I ran it. A dropout counter having a width of 5 μsec or more and an attenuation of a reproduced signal of −16 dB or more was picked up from this tape as a dropout. The measurement was carried out for 10 rolls, and when the number of dropouts converted per minute was less than 10, the dropout was good, and when 10 or more, it was considered bad.

(11) Edge-damage resistance VTR cassette tape similar to that used in (10)
Using TR, after running 200 passes at 25 ° C. and 65% RH, the pleated elongation at the tape end was evaluated by visual judgment as follows.

◯: No elongation was observed Δ: Slight elongation was observed ×: Clear crease-like elongation was observed, making it difficult to use in practice (12) Output characteristics Commercially available Hi8VTR (SONY company) Manufactured EV-BS300
0) was used to measure C / N at 7 MHz ± 1 MHz. This C / N is a commercially available video tape for Hi8 (12
Compared with 0 minute ME), it was judged as +3 dB or more: excellent +1 to less than +3 dB: good less than +1 dB: poor.

[0049]

EXAMPLES Next, the embodiments of the present invention will be explained based on examples.

Example 1 (Table 1) An aqueous slurry of polydivinylbenzene particles having a particle composition of 81% divinylbenzene was directly subjected to polyethylene-2,6-naphthalenedicarboxylate using a vent type twin-screw kneading extruder. (PEN) and kneaded to obtain PEN particle pellets.

An appropriate amount of this particle pellet and a PEN polymer pellet containing substantially no particle is mixed (0.3 μm).
Diameter polydivinylbenzene particles 0.3% by weight, 0.8 μm
Diameter polydivinylbenzene particles containing 0.03% by weight), 1
After drying under reduced pressure (3 Torr) at 80 ° C. for 8 hours, it was fed to an extruder and melted at 300 ° C. After filtering this polymer with a high-precision filter having a filtering accuracy of removing particles of 3 μm or more with a probability of 95%, a molten sheet is extruded from a T-die die, and an electrostatically applied cast method is used. It was wound around a casting drum having a surface temperature of 25 ° C. and cooled and solidified to form an unstretched film. At this time, the ratio of the die slit gap / unstretched film thickness was set to 10. The discharge amount of the extruder was adjusted to control the total thickness.

This unstretched film was stretched 4.3 times in the longitudinal direction at a temperature of 135 ° C. This stretching is done with two pairs of rolls.
It was carried out in four stages with the peripheral speed difference of Le. This uniaxially stretched film was stretched 5.0 times in the width direction at 140 ° C. using a tenter. This film was heat-treated at 220 ° C. for 5 seconds under a fixed length, and a biaxially oriented polyethylene-2,6-naphthalene dicarboxylate film having a thickness of 7 μm was wound with a winder. At this time, an infrared lamp (output: 12 kW) was used to selectively irradiate a wave number of 600 to 1600 cm ⁻¹ infrared light for 7 seconds, and then wound on a roll.

The characteristics of this biaxially oriented polyethylene-2,6-naphthalene dicarboxylate film are as shown in Table 1, and the output characteristics, thermal dimensional stability, dropout and edge damage resistance are good. there were.

Example 2 (Table 1) An aqueous slurry of polydivinylbenzene particles having a particle composition of 81% divinylbenzene was directly kneaded into PEN using a vent type twin-screw kneading extruder to obtain PEN particle pellets. It was

This particle pellet and a PEN polymer pellet containing substantially no particles are mixed in an appropriate amount, and dried under reduced pressure (3 Torr) at 180 ° C. for 8 hours, and then polymer A: 0.3 μm
m diameter polydivinylbenzene particles 0.5% by weight, 0.8μ
Polymer containing 0.05 wt% of m-diameter polydivinylbenzene particles and polymer B: Extruder 1 and extruder 2 containing polymer containing 0.1 wt% of polydivinylbenzene particles of 0.3 μm diameter, respectively.
And melted at 300 ° C and 305 ° C. Each of these polymers was filtered through a high-precision filter having a filtration accuracy of removing particles having a size of 3 μm or more with a probability of 95%, and then two layers were laminated at the rectangular confluence portion (A / B).

This was wound around a casting drum having a surface temperature of 25 ° C. by an electrostatically applied casting method and cooled and solidified to prepare an unstretched film. At this time, the ratio of the die slit gap / unstretched film thickness was set to 10. Further, the total thickness and the thickness of the A layer were adjusted by adjusting the discharge amount of each extruder.

This unstretched film was stretched 4.5 times in the longitudinal direction at a temperature of 140 ° C. This stretching is done with two pairs of rolls.
It was carried out in four stages with the peripheral speed difference of Le. This uniaxially stretched film was stretched 4.9 times in the width direction at 145 using a tenter. Further, using a tenter at 170 ° C. in the width direction, 1.
It was stretched 15 times. This film was heat-treated at 210 ° C. for 3 seconds under a fixed length to give a total thickness of 4.5 μm and an A layer thickness of 0.4 μm.
A biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film of m was obtained.

This film has a film width of 1500 mm
Infrared lamp (18
kW) was used to selectively irradiate infrared light having a wave number of 600 to 1600 cm ⁻¹ for 10 seconds, and then wound into a roll.

The characteristics of this biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film are as shown in Table 1, and the output characteristics, thermal dimensional stability, dropout and edge damage resistance are good. there were.

Example 3 An aqueous slurry of polydivinylbenzene particles having a particle composition of 81% divinylbenzene was directly kneaded into PEN using a vent type twin-screw kneading extruder to obtain PEN particle pellets.

An appropriate amount of this particle pellet and a PEN polymer pellet containing substantially no particle is mixed (0.45 μm).
m diameter polydivinylbenzene particles 0.4% by weight), 180
After drying under reduced pressure (3 Torr) at 8 ° C for 8 hours, it was fed to an extruder and melted at 300 ° C. After filtering this polymer with a high-precision filter having a filtering accuracy of removing particles of 3 μm or more with a probability of 95%, a molten sheet is extruded from a T-die die, and an electrostatically applied cast method is used. Surface temperature 25
Wrap around a casting drum at ℃ to cool and solidify,
An unstretched film was made. At this time, the gap of the mouthpiece slit /
The unstretched film thickness ratio was set to 10. The discharge amount of the extruder was adjusted to control the total thickness.

This unstretched film was stretched 4.4 times in the longitudinal direction at a temperature of 138 ° C. This stretching is done with two pairs of rolls.
It was carried out in four stages with the peripheral speed difference of Le. This uniaxially stretched film was stretched 5.2 times in the width direction at 143 ° C. using a tenter. This film was heat-treated at 210 ° C. for 5 seconds under a fixed length to give a total thickness of 6 μm biaxially oriented polyethylene-2,6-.
The naphthalene dicarboxylate film was wound with a winder. At this time, carbon dioxide laser (output 10k
W) was used to selectively irradiate a wave number of 600 to 1600 cm ⁻¹ infrared light for 10 seconds, and then wound on a roll.

The characteristics of this biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film are as shown in Table 1, and the output characteristics, thermal dimensional stability, dropout and edge damage resistance are good. there were.

Example 4 In the same manner as in Example 2, except that polyethylene terephthalate was used as the A layer polymer and polyethylene-2,6-naphthalene dicarboxylate was used as the B layer polymer, biaxially oriented polyethylene-2 was used. A 6-naphthalenedicarboxylate film was obtained.

Comparative Example 1 In Example 1, before irradiation with an infrared lamp (before infrared treatment)
This film is referred to as Comparative Example 1.

Comparative Example 2 In Example 2, before irradiation with an infrared lamp (before infrared treatment)
This film is referred to as Comparative Example 2.

Comparative Example 3 The film obtained in Example 3 before irradiation with carbon dioxide laser (before infrared treatment) is referred to as Comparative Example 3.

Comparative Example 4 In Example 4, before irradiation with an infrared lamp (before infrared treatment)
This film is referred to as Comparative Example 4.

[0069]

[Table 1]

[0070]

The biaxially oriented polyethylene-2,6 of the present invention
Since the naphthalene dicarboxylate film and the method for producing the same regulate the crystallinity of the film, excellent output characteristics, thermal dimensional stability, dropout, and edge damaging resistance can be obtained.

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Claims (7)

[Claims] 1. A film containing polyethylene-2,6-naphthalenedicarboxylate as a main component and having a crystallinity of 40% or more. Biaxially oriented polyethylene-2,6- Naphthalene dicarboxylate film. 2. A biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film comprising at least a two-layer structure of an A layer and a B layer, the B layer being the film according to claim 1. . 3. The biaxially oriented polyethylene-2 according to claim 2, wherein the layer A is a film containing polyethylene-2,6-naphthalenedicarboxylate and / or polyethylene terephthalate as a main component. 6-
Naphthalene dicarboxylate film. 4. The layer A containing particles, and the thickness t of the layer A and the average particle diameter d of the particles satisfy a relational expression of 0.2 ≦ d / t ≦ 10. The biaxially oriented polyethylene-2,6-naphthalene dicarboxylate film according to item 3. 5. The biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film according to claim 1, wherein the number H3 of coarse surface projections on at least one side is 10/100 cm ² or less. 6. The biaxially oriented polyethylene-2,6 according to claim 1, wherein the elastic modulus in at least one of the longitudinal direction and the width direction is 900 kg / mm ² or more.
-Naphthalene dicarboxylate film. 7. The biaxial orientation according to claim 1, wherein the crystallinity is increased by at least 2% or more by treating the polyethylene-2,6-naphthalene dicarboxylate film with infrared rays. Polyethylene
A method for producing a 2,6-naphthalenedicarboxylate film.