JP3340063B2 - Method for producing aromatic polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic film.
(Aromatic polyester film) .

[0002]

2. Description of the Related Art Conventionally, photographic light-sensitive materials are subjected to wet development using a developing solution after photographing. However, this method has the following drawbacks, and improvement of this point has been desired. Development, bleaching, fixing, and drying require time for development processing. Since a plurality of tanks containing the developer are required, the size and weight of the developing machine cannot be reduced. It requires labor such as replenishment and disposal of the developer and cleaning of the developing tank. In order to improve this, U.S. Pat. No. 3,152,904, U.S. Pat.
Photosensitive materials processed by a developing method using heat at 80 to 150 ° C. (hereinafter, may be abbreviated as heat development) as described in JP-A-4492, JP-B-43-4924 and the like are proposed. . As one example of this, there is a method in which a precursor of a developing agent is previously contained in the photosensitive layer, which is decomposed by heat to be used as a developing agent, and developed. In such a thermal development system, development processing can be performed in a short time only by applying heat, and the developing machine can be downsized. Furthermore, there is no need to worry about replenishment or disposal of the developer. However, when a photosensitive material of this type is used as a photosensitive material for printing, color misregistration occurs when four plates (blue, green, red, and black plates) are superimposed due to a dimensional change occurring during thermal development. There is a disadvantage. In order to solve this problem, there has been known a method of heat-treating a photographic support under low tension (for example, JP-A-60-22616, JP-A-64-64883, and JP-A-54-64883). -1
No. 58470, U.S. Pat. No. 2,779,684). By applying these low-tension heat treatments, the dimensional change before and after thermal development could be reduced, but with this, poor flatness (longitudinal wrinkle failure: crests in the longitudinal direction of the support followed the roof, Wrinkles generated at a pitch of 10 to 20 cm in the width direction)
This is a major problem for a photographic support requiring high flatness. As a countermeasure, there is known a method of passing between a number of rolls and smoothing wrinkles on the rolls as described in US Pat. No. 3,663,683. However, in this method, the tension loss generated by the pass roll is large, and it is difficult to convey at a low tension, and it is not possible to achieve sufficient dimensional stability.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to the production of a thermoplastic film having good flatness and excellent thermal dimensional stability.
Is to provide the law .

[0004]

SUMMARY OF THE INVENTION These problems are as follows.Good
Aromatic polyesterHow to make filmTo the lawMore achieved
Was. That is, the present invention relates to (1) when the heat shrinkage at 150 ° C.
A certain aromatic polyester film is represented by the following formula (1)-
Heat treatment while transporting under conditions that simultaneously satisfy (3)
Production of aromatic polyester film characterized by the following:
Method, 0.001 ≦ F ≦ 0.05 (1) 120 ≦ T ≦ 220 (2) 1 ≦ (T × L) / (F × 1000) ≦ 800 (3) F = unit added to aromatic polyester film Cross section
Transfer tension per unit (kg / mm² T = heat treatment temperature (° C.) L = longest non-contact conveyance length in heat treatment zone (m) (2) 1 of aromatic polyester film before the heat treatment
The difference between the maximum value and the minimum value of the 50 ° C. heat shrinkage width direction distribution is 0%
Characterized in that heat treatment is performed on a material that is not less than 0.1% or less.
The aromatic polyester film according to item (1),
Production method,as well as  (3) Tens of aromatic polyester films before the heat treatment
Point average roughness (R_z) Is 0.18 μm or more and 8.0 μm or less
Bottom, maximum point height (R_t) Is 0.3 μm or more and 10 μm or less
(1) or heat-treating
Production of aromatic polyester film according to item (2)
OneThe lawTo provide.

[0005] The present invention has been made to clarify that the above-mentioned vertical wrinkle failure occurs due to shrinkage of a thermoplastic film between rolls during a heat treatment step. That is, when the heat treatment is performed at a low tension and a high temperature, the support tends to contract by heat. However, on the pass roll, shrinkage is suppressed by the frictional force between the film and the roll. On the other hand, since the film can be freely shrunk between the rolls, the width of the film is reduced. In order to eliminate such a difference in width between the roll and the roll, undulation occurs near the roll. At high temperatures, it is easy to creep, and such deformation becomes permanent deformation. Therefore, such vertical wrinkles are likely to occur when the sheet is conveyed at a high temperature and a low tension. Therefore, vertical wrinkles are more likely to occur as the length between the pass rolls in the heat treatment zone, that is, as the non-contact conveyance length is longer, and as the temperature is higher and the tension is smaller. In the method of the present invention, the heat treatment without the generation of vertical wrinkles is performed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The heat treatment conditions in the method for producing a thermoplastic film of the present invention satisfy the above formulas (1) to (3). If the transport tension F exceeds the range of the present invention, heat shrinkage tends to increase, which is not preferable. On the other hand, if it is less than the range of the present invention, a transport trouble such as meandering is likely to occur, which is not preferable. Conveying tension is usually 0.001 kg / mm ² or more 0.05 kg / mm ² or less, preferably 0.003kg
/ Mm ² or more and 0.03 kg / mm ² or less, more preferably 0.007 kg / mm ² or more and 0.02 kg / mm ^2.
It is as follows. Such tension can be achieved by adjusting a motor installed on at least one of the winding side and the sending side. At this time, it is preferable to install a tension pickup and adjust while monitoring the tension. However, when the film is wound with such a low tension, the film is easily broken. Therefore, it is preferable that the film is wound with a high tension after the tension is cut in front of the winding section.

The heat treatment temperature is usually from 120 ° C. to 220 ° C., preferably from 135 ° C. to 200 ° C.
The temperature is more preferably from 5 ° C to 180 ° C. If the temperature exceeds this range, the oligomer contained in the thermoplastic film is deposited on the surface and the haze tends to increase, which is not desirable. If the temperature falls below this range, heat shrinkage tends to increase, and the object of the invention cannot be achieved. Such temperature control may be achieved by blowing hot air into a heat treatment zone using a heat insulating material,
The temperature of the plastic film may be raised by heat transfer by bringing it into contact with a high-temperature heat medium such as a heat roll, or the temperature may be raised by radiant heat using something like an infrared heater. Either method may be used, but it is preferable to reduce the temperature distribution in the width direction in order to reduce the distribution of thermal contraction in the width direction. This can be achieved by installing fins at the outlet of the hot air and adjusting the direction of the wind to eliminate pools, or by split control of heat rolls and infrared heaters so that the temperature at both ends, where the temperature tends to be low, will be high. Can be achieved. Temperature T here the heat treatment is at a temperature higher than the glass transition temperature T _g.

The maximum length between the pass rolls is usually in the range of 1 ≦ (T × L) / (F × 1000) ≦ 800 shown in the above equation (3) as a function of the tension (F) and the heat treatment temperature (T). And preferably 2 ≦ (T × L) / (F × 100
0) ≦ 200, more preferably 4 ≦ (T × L) / (F
(× 1000) ≦ 80 is preferably set. Below this range, the roll interval is short and a large number of pass rolls need to be installed, and the transport tension needs to be set large because of the tension loss that occurs here, and dimensional stability tends to deteriorate. On the other hand, if it exceeds this range, the shrinkage of the base width is likely to be large, and vertical wrinkles are likely to occur, which is not desirable. The length between the pass rolls here refers to the maximum length present in the heat treatment zone. This is because vertical wrinkles occur in any one place beyond the range of the present invention, so the maximum length must be within the above range. This point is important because vertical wrinkles that occur once between pass rolls are hard to disappear.

Further, the present invention can further reduce the problem of vertical wrinkles by improving the thermoplastic film used. First, the heat shrinkage at 150 ° C. of the thermoplastic film before the heat treatment is preferably 0.01% or more and 0.4% or less, preferably 0.05% or more and 0.3% or less, more preferably 0.1% or less. That is, a material of 1% or more and 0.25% or less is used. That is, by using a thermoplastic film having a small heat shrinkage, the shrinkage between the pass rolls generated during the heat treatment is reduced, and there is an effect of suppressing the generation of vertical wrinkles. Heat shrinkage of 0.4
%, The dimensional stability of the photographic image deteriorates. On the other hand, a thermoplastic film having a heat shrinkage at 150 ° C. lower than the above range has sufficiently high thermal dimensional stability and does not need to perform the heat treatment of the present invention. Such a support has improved stretching conditions,
A method of pre-heat treatment may be mentioned, but the method is more preferable. The method of the present invention is carried out at 120 ° C. to 22
The heat treatment is performed at 0 ° C., more preferably 130 ° C. to 200 ° C., further preferably 150 ° C. to 190 ° C.
Thereby, the heat shrinkage is made to some extent in advance, and the amount of heat shrinkage generated by the heat treatment of the present invention is reduced. Therefore, since the pre-heat treatment does not require high dimensional stability as in the above-described heat treatment, it is preferable that the tension is increased by that amount so as not to generate vertical wrinkles. Such heat treatment may be performed alone, but if there is a coating step, it is more efficient to perform it in the subsequent drying step. When used as a photographic support, it is preferable to carry out this drying step in order to apply an undercoat and a backing layer. One of them can be achieved by reducing the draw ratio and increasing the heat setting temperature, but both are directions in which the elastic modulus of the thermoplastic film is reduced, which is not preferred.

The second improvement of the thermoplastic film is that the difference between the maximum value and the minimum value in the width direction distribution of the heat shrinkage at 150 ° C. before the heat treatment is 0% or more and 0.10 or less, more preferably 0% or more and 0% or less. 0.07% or less, more preferably 0% or more and 0.05
% Of the thermoplastic film is preferably used. That is, it is preferable to use a thermoplastic film whose heat shrinkage is uniform in the width direction. This is because if the amount of heat shrinkage is uneven, the shrinkage is locally large, and vertical wrinkles are easily generated therefrom. Such thermoplastic films have improved film-forming conditions,
This can be achieved by a pre-heat treatment. Can be achieved by increasing the heat setting temperature for the end portion where heat shrinkage tends to increase. Is the same as described above, and is intended to reduce the difference between the maximum value and the minimum value by reducing the absolute value of the thermal contraction.

Third, the ten-point average roughness (R _z ) of the thermoplastic film is preferably 0.18 μm or more and 8.0 μm or less, more preferably 0.20 μm or more and 6.0 or less.
μm or less, more preferably 0.3 μm or more and 4.5 μm
It is as follows. _Rz indicates the difference between the average value of 10 points from the highest peak in the reference length and the average value of 10 points from the deepest valley. That is, when the height of the projections larger than the average unevenness (average roughness; _Ra ) is within the range of the present invention, the friction between the roll and the thermoplastic film can be effectively reduced. Further, for the same reason, the maximum point height (R _z ) is set to 0.3 μm or more and 10.0 μm or less, more preferably 0.4 μm or more and 8.0 μm or less, and further preferably 0.6 μm or more and 6.0 μm or less. Is preferred. R _t indicates the difference between the highest protrusion and the deepest valley existing within the reference length. If both _Rz and _Rt are below the range of the present invention, the flatness tends to decrease, and if _Rz and Rt exceed, the added fine particles are peeled off to cause roll contamination, which is not preferable.

[0012] Such a thermoplastic film adjusts friction with a pass roll by imparting irregularities to the surface of the thermoplastic film, thereby facilitating thermal shrinkage even on the pass roll. As a result, since shrinkage can be achieved in the same manner as the thermoplastic film between pass rolls that is not subjected to binding force, the occurrence of vertical wrinkles can be reduced. If the amount exceeds the range of the present invention, the fine particles added for achieving the surface roughness are peeled off, which undesirably contaminates the process. On the other hand, if it is lower than this, the effect is not obtained and vertical wrinkles are likely to occur. Such a thermoplastic film can be dealt with by increasing the amount of fine particles (filler) added to the thermoplastic film by providing a fine particle layer on the outermost surface.

The method of (1) is an inorganic substance such as silica, alumina, barium sulfate, calcium carbonate, titania, tin oxide, indium oxide, and talc, or polystyrene, polymethyl methacrylate, polymethacrylate,
A method in which organic fine particles such as polyacrylonitrile, cellulose, and gelatin are applied together with a binder. The shape of these fine particles is not particularly limited, and they can be used in a needle shape, a spherical shape, a plate shape, or a crushed shape. The preferred size is 0.1 to 15 μm, more preferably 0.2 to 10 μm, and still more preferably 0.3 to 7 μm.
It is. The addition amount of the matting agent is 0.1 per one side 1m ²
It is 50 mg, more preferably 0.2 to 30 mg, even more preferably 0.3 to 20 mg. Among these fine particles, particularly preferred are ZnO, TiO ₂ , SnO ₂ , A
l ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, M
Fine particles of at least one crystalline metal oxide selected from oO ₃ and V ₂ O ₅ or a composite oxide thereof. More preferred are conductive materials containing SnO ₂ as a main component and containing about 5 to 20% of antimony oxide and / or further containing other components (for example, silicon oxide, boron, phosphorus, and the like). The use of these conductive fine particles can suppress a failure with dust caused by static electricity generated during heat treatment. These conductive inorganic fine particles have a volume resistivity of 10 ⁷ Ωcm or less, more preferably 10 ⁶ Ωcm or less,
More preferably, it is 10 ⁵ Ωcm or less. The binder for dispersing these fine particles is not particularly limited, and gelatin, water-soluble polyester, polyurethane, styrene-butadiene rubber, polyvinylidene chloride, polyvinyl chloride, polyurethane, polyacrylester, polymethacrylester, polyamide, or the like is used. Can be.

Prior to these coatings, it is preferable to carry out a glow discharge treatment, a corona treatment, an ultraviolet treatment and a flame treatment in order to improve the adhesiveness. Known methods can be used for these coatings. For example, dip coating method,
An air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, or an extrusion coating method using a hopper described in US Pat. No. 2,681,294, or US Pat.
The multi-layer simultaneous coating method described in the specifications of Nos. 761418, 3508947 and 2761791 can be used.

In the method (1), a filler such as an inorganic substance such as silica, alumina, barium sulfate, calcium carbonate, titania, tin oxide, indium oxide, and talc is kneaded into a thermoplastic film. The shape of these fillers is not particularly limited, and may be needle-like, spherical, plate-like, or crushed. The preferred size is 0.01 to 10 μm, more preferably 0.05 to 5 μm
m, more preferably 0.1 to 3 μm. The addition amount of the filler is 10 to 1000 ppm, more preferably 20 ppm.
~ 500 ppm, more preferably 30-300 ppm
Is

The thermoplastic film can be manufactured by applying the heat treatment method of the present invention is made of Kaoru aromatic polyester
It is . The aromatic polyester as referred to herein refers to something more than 50 mole% of the dicarboxylic acid to form a polyester composed of an aromatic dicarboxylic acid. More specifically, a polyethylene terephthalate polymer (PET), a polyethylene naphthalate polymer, a polybutylene terephthalate polymer, and a polybutylene naphthalate polymer are exemplified. More preferred are polyethylene terephthalate and polyethylene naphthalate. The average molecular weight (M _w ) is preferably 5,000 to 1,000,000, more preferably 10,000 to 300,000.

It is desirable that these thermoplastic films are formed into two or more axes. For example, after melting between the melting point (T _m ) of the thermoplastic film and T _m + 50 ° C., it is extruded into a cooling drum having a glass transition temperature (T _g ) of −50 ° C. to T _g + 20 ° C. to form an unstretched sheet. At this time, it is also preferable to apply static electricity to the cooling drum. The unstretched sheet T _g ~T _g + 60 extends vertically into 2 to 4 times between ° C., further stretched in the transverse two to five times between T _g ~T _g + 60 ℃. This is heat-set at T _m -60 ° C. to T _m for 5 seconds to 1 minute. After that, it is also preferable that the temperature is relaxed by 0 to 10% in at least one of the horizontal and vertical directions at T _m −60 ° C. to T _m . After that, it is also preferable that the film is further stretched longitudinally / horizontally. The thickness of the thermoplastic film thus obtained is 50 to 500 μm
Is more preferable, more preferably 70 to 300 μm, and still more preferably 90 to 200 μm.

By carrying out the above-mentioned present invention, the height of the vertical wrinkles is 0 μm or more and 200 μm or less, more preferably 0 μm or more and 150 μm or less, further preferably 0 μm or more and 100 μm or less.
It has a high flatness of not more than μm and a heat shrinkage in the longitudinal direction at 120 ° C. of not less than 0.001% and not more than 0.05%, more preferably not less than 0.001% and not more than 0.04%, further preferably not more than 0.1%. An excellent thermoplastic film having high thermal dimensional stability of 001% or more and 0.03% or less can be produced. As a result, when used as a photographic support, particularly when used as a photographic light-sensitive material support involving thermal development, a high-quality image that does not cause image displacement or print blur when overprinted on a printing original plate (PS plate). A support can be provided. The photographic light-sensitive material of the present invention can be formed by coating a photographic light-sensitive layer on the support thus obtained. As preferred photographic materials, those described in Japanese Patent Application Nos. 9-226699 and 8-158652 can be used.

Hereinafter, the measuring method used in the present invention will be described. (1) Height of vertical wrinkles The support after the heat treatment is placed in a width direction of 50 cm × length direction of 30
Cut to cm. This is floated on water so that air bubbles do not enter, and a laser focus displacement meter (for example, LC2210 type manufactured by KEYENCE CORPORATION) is placed 50 cm / width in the width direction on this.
Scan in minutes. The maximum value minus the minimum value (excluding both ends) thus obtained was defined as the vertical wrinkle height in the width direction of the support. (2) Heat shrink at 150 ° C The thermoplastic film before heat treatment was placed in the longitudinal direction (longitudinal direction; M
D) Cut to 25 cm x width direction (TD) 5 cm. Drill two holes at intervals of 20 cm, and add 1 hole at 25 ° C and 60% RH.
Measured using 2 hours or more humidity rear pin gauge (the length is defined as L _1). After that, it is left for 30 minutes without applying tension to the air thermostat at 150 ° C. After this, 25 ° C 60% R
After adjusting the humidity for 12 hours or more with H, the length is measured again using a pin gauge (this length is defined as L ₂ ). The thermal dimensional change rate is determined based on the following equation. 120 ° C. heat shrinkage (%) = ｛100 × (L ₁ −L ₂ ) / L
₁ Absolute value of こ の This measurement is made at five points in the width direction, and the average value, maximum value, and minimum value are obtained.

(3) Heat shrinkage at 120 ° C. The thermoplastic film after the heat treatment is placed in the machine direction (MD) 25c.
It is cut in the mx width direction (TD) 5 cm. 20cm for this
Two holes are formed at intervals, and after measuring the humidity at 25 ° C. and 60% RH for 12 hours or more, the measurement is performed using a pin gauge (this length is defined as L ₁ ). Then, it is pressed on a smooth stainless steel plate having a thickness of 10 mm heated to 120 ° C. for 30 seconds. After this, 25 ℃ 6
After humidity control at 0% RH for 12 hours or more, the length is measured again using a pin gauge (this length is defined as L ₂ ). The thermal dimensional change rate is determined based on the following equation. 120 ° C. heat shrinkage (%) = ｛100 × (L ₁ −L ₂ ) / L
Absolute value of ₁ ｝ This is measured at both ends and the center of the thermoplastic film, and the average value is obtained. (4) Ten-point average roughness (R _z ), maximum roughness (R _t ) Measured under the following conditions at 25 ° C. and 60% RH using a universal surface profiler SE-3C manufactured by Kosaka Laboratory Co., Ltd. . Measurement length: 2.5 mm Cut-off: 0.25 mm Measurement is performed on both sides of the sample film, and the one with the larger value is indicated. (5) Tension A differential transformer type tension tester (for example, LX-TC-100 manufactured by Mitsubishi Electric Corporation) is installed on the roll immediately before and after the heat treatment zone, and the tension at 25 ° C. is measured. I asked.

[0021]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. Example-1 (1) Preparation of Support (1-1) Preparation of Polyethylene Terephthalate (PET) Support Using terephthalic acid and ethylene glycol, IV = 0.66 (phenol / tetrachloroethane = 6) according to a conventional method.
(Measured at 25 ° C. in / 4 (weight ratio)). This was pelletized and dried at 130 ° C. for 4 hours.
After being melted at 0 ° C., it was extruded from a T-die and then rapidly cooled to prepare an unstretched film having a thickness of 120 μm after heat setting. This was longitudinally stretched 3.3 times using rolls having different peripheral speeds, and then transversely stretched 4.5 times using a tenter. The temperatures at this time were 110 ° C. and 13 ° C., respectively.
It was 0 ° C. After that, it was heat-set at 240 ° C. for 20 seconds and relaxed 4% in the horizontal direction at the same temperature. After slitting the chuck portion of the tenter, knurling was applied to both ends with a width of 1 cm.

(1-2) Preparation of polyethylene-2,6-naphthalate (PEN) support Using dimethyl naphthalene-2,6-dicarboxylate and ethylene glycol, IV = 0.58 (phenol / tetrachloroform) Ethane = 25 ° C in 6/4 (weight ratio)
PEN) was obtained. After pelletizing this, 15
After drying at 0 ° C. for 4 hours, it was melted at 320 ° C., extruded from a T-die, then rapidly cooled, and the film thickness after heat fixing was 120 μm.
An unstretched film having such a thickness was prepared. This was longitudinally stretched 2.8 times using rolls having different peripheral speeds, and then transversely stretched 3.7 times using a tenter. The temperatures at this time were 140 ° C. and 150 ° C., respectively. After this,
After heat setting at 250 ° C. for 20 seconds, the film was relaxed 4% in the transverse direction at the same temperature. After slitting the chuck portion of the tenter, knurling was applied to both ends with a width of 1 cm. (2) Preparation of Coating Layer The following undercoat and back coating layers were provided on the above support as shown in Table 1.

[0023]

[Table 1]

[0024]

[Table 2]

(2-1) Corona treatment Both surfaces of the support were subjected to corona treatment (using a solid state corona treatment machine 6KVA model manufactured by Pillar Co., at 20 m / min at room temperature at room temperature) prior to coating. From the current and voltage readings at this time, 0.3
Processing of 75 kV · A · minute / m ² is performed. The processing frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm. On this, the following layer was applied. (2-2) First layer of undercoat A water-dispersed latex having the following composition was applied using a wire bar to a dry film thickness of 0.3 µm, and dried at 120 ° C for 2 minutes. Butadiene-styrene copolymer latex 13 ml (solid content 43%, butadiene / styrene weight ratio = 32/68) 2,4-dichloro-6-hydroxy-S-triazine sodium 7 ml 8% aqueous solution sodium laurylbenzenesulfonate 1% Aqueous solution 1.6 ml Colloidal silica Particle size and amount are described in Table 1 Distilled water 80 ml

(2-3) Second Layer of Undercoat An aqueous solution having the following composition was applied using a wire bar so that the dry film thickness was 0.14 μm. Table 1 shows the presence / absence of application and drying conditions. Gelatin 0.9 g Methyl cellulose (Metroose SM15 substitution degree 1.79-0.1 g 1.83) Acetic acid (concentration 99%) 0.02 ml Distilled water 99 ml

(2-4) Back First Layer (Conductive Layer) An aqueous dispersion of acrylic latex containing a conductive material having the following composition was applied so that the dry film thickness became the value shown in Table 1, and 180 ° C.
For 30 seconds to produce a support having a surface electric resistance of 10 ⁶ Ω. Acrylic resin aqueous dispersion 2.0 parts by weight (Julima-ET410, solid content 20% by weight, manufactured by Nippon Pure Chemical Co., Ltd.) Tin oxide-antimony oxide aqueous dispersion 18.1 parts by weight (average particle size 0.1 μm, (17% by weight) Polyoxyethylene phenyl ether 0.1 part by weight Colloidal silica The size and amount of addition are described in Table 1. Distilled water was added to the mixture to prepare 100 parts by weight.

(2-5) Polyolefin Layer (Slip Layer) An aqueous dispersion of polyolefin latex having the following composition was applied so that the dry film thickness was as shown in Table 1. Table 1 shows the presence / absence of application and drying conditions. 3.0 parts by weight of polyolefin (27% by weight of Chemipearl S-120, manufactured by Mitsui Petrochemicals Co., Ltd.) 2.0 parts by weight of colloidal silica (Snowtex C, manufactured by Nissan Chemical Co., Ltd.) 0.3 parts by weight of epoxy compound (Denacol EX-614B, manufactured by Nagase Kasei Co., Ltd.) Distilled water was added to adjust the total to 100 parts by weight. (3) Heat treatment Prior to the heat treatment, the following evaluation was carried out according to the above-mentioned method. It was shown to. Heat shrink at 150 ° C. _Ra , _Rt Heat treatment was performed under the conditions shown in Table 1.

(4) Evaluation The following evaluation was carried out on the heat-treated thermoplastic film according to the above-mentioned method, and the results are shown in Table 1. Vertical wrinkles 120 ° C. heat shrinkage (5) Preparation of photosensitive material The photosensitive layer shown in Table 1 was applied to the undercoat side of the thermoplastic film which was provided with the above-mentioned undercoat and back layer and subjected to heat treatment. This was printed with a test pattern using xenon flash light having an emission time of 10 ^-4 SEC, and then developed at 120 ° C. for 30 seconds using a heat developing machine described in JP-T-7-505488.
When this was baked on a PS plate, in the present invention, good flatness and dimensional stability were achieved, and good baking was realized.
On the other hand, in the comparative example, blurring caused by vertical wrinkles and misalignment caused by dimensional change occurred during printing.

[0030]

The thermoplastic film obtained by the method of the present invention has good flatness and excellent thermal dimensional stability, and when used as a photographic support, causes troubles such as blurring and misalignment due to dimensional change due to thermal development. do not do. Further, according to the method for producing a thermoplastic film of the present invention, a thermoplastic film having excellent properties as described above can be obtained by heat treatment.

Continuation of the front page (56) References JP-A-8-142209 (JP, A) JP-A-64-64833 (JP, A) JP-A-54-68880 (JP, A) JP-A-54-158470 (JP) , A) JP-A-11-47676 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 71/00-71/04 G03C 1/00-1/95

Claims (3)

(57) [Claims] 1. A heat shrinkage at 150 ° C. of 0.01% or more and 0.4% or more.
% Of an aromatic polyester film, wherein the aromatic polyester film is heat-treated while being conveyed under conditions that simultaneously satisfy the following formulas (1) to (3). 0.001 ≦ F ≦ 0.05 (1) 120 ≦ T ≦ 220 (2) 1 ≦ (T × L) / (F × 1000) ≦ 800 (3) F = unit cross-sectional area added to the aromatic polyester film Transfer tension per unit (kg / mm ² ) T = heat treatment temperature (° C.) L = longest non-contact transfer length in heat treatment zone (m) 2. The heat treatment of the aromatic polyester film before heat treatment wherein the difference between the maximum value and the minimum value of the 150 ° C. heat shrinkage width direction distribution is 0% or more and 0.1% or less. The method for producing an aromatic polyester film according to claim 1. 3. The ten-point average roughness (R _z ) of the aromatic polyester film before the heat treatment is 0.18 μm or more and 8.0.
μm or less, maximum point height (R _t ) is 0.3 μm or more and 10 μm
3. The method for producing an aromatic polyester film according to claim 1 or 2, wherein the material having a molecular weight of m or less is heat-treated.