JPH08291216A - Polyester and production of substrate for photography using the same - Google Patents

Abstract

PURPOSE: To obtain a polyester-based substrate for photography, forming a polyester having a specific melt electric resistance value into a film and stretching the film by an electrostatic impression method, slight in coloring, excellent in electrostatic adhesivity and transparency. CONSTITUTION: A polyester such as polyethylene-2,6-naphthalate, etc., having 6.0-7.0 melt electric resistance value shown by common logarithm in a molten state at 300 deg.C is made into a film at 20-120m/minute film forming and stretching rate by an electrostatic impression method so as to make an undrawn film having 0.45-2.5mm thickness. A metal chloride soluble in glycol and a nitrogen atom-containing hetero cyclic compound are added before starting of the polyester polycondensation reaction and then the polycondensation reaction is preferably carried out.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyester photographic support such as polyethylene naphthalate,
In particular, the present invention relates to a high-speed melting film forming method having excellent electrostatic adhesion to a cooling drum. The present invention also relates to a method for producing a polyester photographic support having good flatness, excellent transparency and little coloring.

[0002]

A polyester film is usually obtained by subjecting a polyester obtained by a polycondensation reaction of a diol ester of a dicarboxylic acid or a low polymer thereof after a transesterification reaction or a direct esterification reaction between a dicarboxylic acid component and a diol component. It is produced by melt extrusion and further uniaxially or biaxially stretching, but the adhesion between the molten unsolidified sheet and the cooling drum at the time of melt extrusion determines the flatness of the film surface. It is a very important factor for the required film formation of the photographic support film, and in order to improve this, an electrode for applying a high voltage is provided between the extruder die and the cooling drum, and the unsolidified polyester sheet is provided. It is known to generate an electric charge and enhance the adhesiveness with the cooling drum (hereinafter referred to as electrostatic adhesiveness).

As a method of lowering the melting electric resistance value of polyethylene naphthalate (PEN), it is known to add an ethylene glycol-soluble metal compound or a phosphorus compound, but the thermal stability is lowered. For example, JP-A-62-11
Although effective for forming a thin unsolidified sheet described in Japanese Patent No. 3529, when a thick film as the object of the present invention is formed or the film forming speed is increased, the amount of charge deposited on the unsolidified sheet is increased. Due to the lack of water, the adhesion with the cooling drum deteriorates, and the surface becomes a wavy or wavy state. The film obtained by stretching such a sheet has poor surface flatness and cannot be used as a photographic film. When such a support is coated with an undercoat layer, a backcoat layer and a photographic emulsion layer, wrinkles and uneven coating (uneven thickness) occur.

Further, P obtained by direct esterification reaction
Since the raw material of EN is naphthalenedicarboxylic acid having a low purity, the film obtained by film-forming and stretching is colored.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a polyester excellent in electrostatic adhesion during melt film formation and a high-speed melt film formation method. Another object of the present invention is to provide a method for producing a polyester-based photographic support having a sheet surface that is not in a crease-like or corrugated state, excellent in flatness and transparency, and less colored.

[0006]

The present invention is obtained by subjecting a polyester having a melting electric resistance value (logR) of 6.0 or more and less than 7.0 and a polycondensation reaction by an ester exchange reaction of an aromatic dicarboxylic acid diester and a diol. In the method for producing a polyester support for forming the obtained polyester into a film by an electrostatic application method, a common logarithm (l
and a melt electric resistance value (logR) represented by og) of 6.0 or more and less than 7.0 is formed by an electrostatic application method to obtain a polyester-based photographic support. It was The polyester mentioned here includes PET (polyethylene terephthalate) and PEN.
(Polyethylene naphthalate), polycyclohexane dimethylene terephthalate (hereinafter referred to as PCT), polybutylene terephthalate (hereinafter referred to as PBT), polybutylene naphthalate (hereinafter referred to as PBN), and the like. A polyester having PEN as a main component is preferably used for the purpose of the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a polyester containing PEN as a main component and having a melt electric resistance value (logR) of 6.0 or more and less than 7.0 and a method for producing a photographic support therefor. To the extent that it does not damage, for example, adipic acid, aliphatic dicarboxylic acid components such as sebacic acid, phthalic acid, isophthalic acid, biphenyldicarboxylic acid, sodium 5-sulfoisophthalate, 4-sulfo-2,6-naphthalenedicarboxylic acid, etc. Aromatic dicarboxylic acid components, alicyclic dicarboxylic acid components such as 1,4-cyclohexanedicarboxylic acid can be copolymerized, and diethylene glycol,
It is also possible to copolymerize glycols such as triethylene glycol, butanediol, 1,4-cyclohexanedimethanol and polyethylene glycol, and polyfunctional components such as trimellitic acid and glycerin. Preferably,
It is a polyethylene-2,6-naphthalate containing at least 70 mol% of ethylene glycol and (2,6-) naphthalenedicarboxylic acid in the total dicarboxylic acid. PEN containing 90 mol% or more of 2,6-naphthalenedicarboxylic acid is preferable. Further, as another naphthalenedicarboxylic acid component, 2,7-naphthalenedicarboxylic acid or 1,5-naphthalenedicarboxylic acid may be copolymerized within a range not exceeding 5 mol%. Further, as additives, known antioxidants such as hindered phenols, silica as a lubricant, inert inorganic particles such as silica, alumina, calcium compounds and the like, organic cross-linked polymer particles, further published by the Institute of Invention and Innovation The dyes and pigments shown in Japanese Patent No. 94-6023 can be added as required. In the film forming step of the method for producing polyester of the present invention, the thickness of the unstretched film is 0.
3 mm to 2.5 mm, preferably 0.45 mm to 2.5 mm, more preferably 0.7 mm to 2.0 mm, and the film forming width is 0.2.
It is m to 3 m. The draw ratio is 2 to 5 in the machine direction and the transverse direction.
The thickness of the film after biaxial stretching and orientation is 60 to 120 μm. Further, the biaxial stretching orientation may be simultaneous biaxial stretching or sequential biaxial stretching. After stretching, heat setting and heat relaxation treatment are further performed at a temperature 5 ° C. to 30 ° C. lower than the melting point of the polyester. In order to reduce curling curl, heat treatment at a temperature below the glass transition point described in US Pat. No. 4,141,735 may be performed. The film forming speed is 20 m / min or more and 120 m / min or less, preferably 30 m / min or more and 100 m / min or less, and more preferably 40 m / min or more and 90 m / min or less. The cooling drum speed at that time is 3 m / min or more and 30 m / min or less.
Further, in the method for producing a polyester of the present invention, a component that lowers the melting electric resistance is added from the end of the transesterification reaction between the aromatic dicarboxylic acid diester and the diol, specifically ethylene glycol, to the start of the polycondensation reaction. is necessary.

In the present invention, a glycol-soluble compound selected from magnesium compounds, manganese compounds or zinc compounds and a heterocyclic compound containing a nitrogen atom are preferably used together as the component. For example, naphthyridine, phthalazine, indolizine, imidazole, benzimidazole, isoquinoline, quinazoline, quinoxaline, pteridine, pyrimidine, pyridazine, pyrazine,
There are diazabicycloundecene-1, diazabicyclooctane, 1,5-diazabicyclo (4.3.0) non-5-ene and their derivatives. As the imidazole derivative, 2-
Methylimidazole, 2-ethylimidazole 2-ethyl-5
-Methylimidazole, 2-methyl-5-ethylimidazole, 2-phenylimidazole, 2,5-dimethylimidazole, 4,5-diphenylimidazole, 2,4,5-triphenylimidazole and the like. A heterocyclic compound containing two or more nitrogen atoms is preferable, and as the glycol-soluble magnesium compound, manganese compound or zinc compound, a metal acetate salt is preferable, and magnesium acetate is particularly preferable. The addition amount is 1.5 to 6 mol% (per ton of polyester, the same applies hereinafter), preferably 2 to 4 mol%. or,
Organic sulfonic acid compounds such as sodium dodecylbenzene sulfonate and naphthoic acid, organic carboxylic acid compounds or metal salts thereof are used, but they have good compatibility with PEN and do not impair the transparency of the film, and also for various photographic applications. It is necessary that the compound does not precipitate outside the film during processing (for example, development, washing with water, drying, etc.). On the other hand, when these compounds are used, they may be added during the production of the polyester, or may be added and mixed during the film formation.

The film forming method of the present invention is based on the electrostatic application method. That is, the support is a non-stretched sheet that is obtained by cooling the unsolidified sheet extruded from the die of the melt extruder with a cooling drum by a melt extruder heated to 280 ° C to 310 ° C, and then in the longitudinal and transverse directions. It is obtained by sequential or simultaneous stretching orientation of 2 to 5 times and further by heat treatment such as heat fixation and thermal relaxation. It is composed of thin wires between the die of the melt extruder and the cooling drum at right angles to the flow of the unsolidified sheet. Provide an electrode (for example, 0.1 mm diameter tungsten wire), 5 KV
A direct current voltage of about 15 KV is applied to improve the adhesion of the unsolidified sheet to the cooling drum, and an unstretched sheet having good flatness is obtained. In the present invention, the melting electric resistance value expressed in common logarithm (hereinafter referred to as logR, where R represents the electric resistance value)
Is the electric resistance value between the two electrodes in the melted polyester, and the higher the melting temperature is, the lower the logR is, but here, the temperature was 300 ° C. which was the melting condition during the actual film formation. LogR of FIG. Electrostatic adhesion is log
R is 6.0 or more and less than 7.0, preferably 6.1 or more and 6.
It was found that it is excellent when it is 9 or less, more preferably 6.3 or more and 6.8 or less.

Even if the polyester has a log R of 7.0 or more, a relatively thin sheet having a thickness of 250 μm or less has a good electrostatic adhesion, but a thick sheet having a thickness of 0.45 mm or more and 2.5 mm or less is When the amount of charge deposition is insufficient and the film formation is attempted at a high speed of 30 m / min or more, the adhesion to the cooling drum deteriorates, and the film surface becomes crease-like or has a wavy surface, which is used as a photographic support. I can not use it. Further, when the glycol-soluble metal compound is excessively added or the amount of the phosphorus compound added is reduced to set logR to 6.0 or less, foreign substances are easily generated in the case of the metal compound. In the case of a phosphorus compound, the heat-resistant coloring property is reduced.
Both are not preferable as a photographic support. In order to clarify the present invention, the method for producing the polyester referred to in the present invention will be described in more detail by exemplifying the method for producing PEN.

The PEN used in the present invention can be manufactured by a batch method, a semi-continuous method or a continuous method, and the batch method will be described. 2,6-naphthalenedicarboxylic acid dimethyl ester (hereinafter referred to as NCM) and ethylene glycol (M) at 180 ° C. in the presence of a transesterification catalyst selected from (M) ethylene glycol-soluble manganese, magnesium, calcium and zinc compounds. ~ 260 ° C
Then, the by-produced methanol is distilled off from the rectification column to carry out an ester exchange reaction to obtain a glycol ester of 2,6-naphthalenedicarboxylic acid or a low polymer thereof (hereinafter referred to as an oligomer). It usually takes 3 to 6 hours. The obtained oligomer is then added in an amount of 0.5 to 2.5 mol%,
Preferably 1.0-2.0 mol% antimony compound and 0.3
-6.5 mol%, preferably 0.6-5.0 mol% of phosphoric acid or phosphorous acid or their esters, and finally 2
When PEN is produced by polycondensation by heating at 80 ° C to 300 ° C and under a vacuum of 1 mmHg to 0.2 mmHg for 2 hours to 5 hours while distilling off ethylene glycol, polycondensation is carried out after completion of the transesterification reaction. A component that lowers the melting electric resistance by the start of the reaction, for example, the glycol-soluble magnesium acetate and a heterocyclic compound containing a nitrogen atom are added.

The transesterification catalyst may be any of the glycol-soluble metal compounds described above, but among them, manganese compounds, particularly manganese acetate, are preferably used.
If the amount of the phosphorus compound is too small, the heat-resistant coloring property of the polymer will be poor, and if it is too large, the electrostatic adhesion will be impaired. When the amount of the heterocyclic compound containing a nitrogen atom is too large, it causes yellowing of the polyester produced, so the addition amount is 5 to 100 ppm, preferably 10 to 50 ppm.

As the polycondensation reaction catalyst, an antimony compound such as antimony trioxide and a titanium compound such as titanium butoxide are used, and among them, an antimony compound, for example, antimony trioxide is preferable. The polyester thus obtained is generally extracted in a strand form from a polymer outlet provided in the bottom of a kettle, cooled in a water tank, and then cut and pelletized. The pellets are dried under vacuum at 100 ° C. to 200 ° C. for 5 hours to 20 hours and subjected to various physical property measurements and film formation.

Although the production of the polyester of the present invention has been described by the batch type melt polymerization method, it is also possible to carry out the solid phase polymerization after the melt polymerization. The intrinsic viscosity of the polyester of the present invention varies depending on its main component, but is 0.45 or more and 0.70.
The following is preferable, and the terminal carboxyl group concentration is 10 eq /
10 ⁶ g to 50 eq / 10 ⁶ g are preferred. Melt extrusion is carried out at 290 ° C to 310 ° C by extruding a molten unsolidified sheet from an extruder's gold port, bringing it into close contact with a cooling drum by an electrostatic adhesion method, and then peeling it off and stretching it in a longitudinal direction and a transverse direction for biaxial orientation. The film. This time, the biaxial stretching ratio was appropriately selected according to the film forming speed. During melt extrusion
It is desirable to install a filter from the extruder to the extruder gold port in order to remove dust and foreign substances mixed or generated in the process.

[0015]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.
In addition, "part" in an Example means a weight part unless there is particular notice. The various analytical values were according to the following methods. Intrinsic viscosity: The polymer is dissolved in a phenol / tetrachloroethane mixed solution (mixed to 6/4 by weight) and measured at 25 ° C. The measurement was performed by measuring four points while changing the dissolved concentration of the polymer. Pellet hue: The b value of the pellet was measured with a color difference meter manufactured by Nippon Denshoku Co., Ltd. Melting electric resistance (logR): Put dried pellets in a test tube and melt in an oil bath at 300 ° C. Then, two electrodes made of SUS having a diameter of 2 mm are fixed at intervals of 1 cm to the molten polymer, and 5 cm is applied to the molten polymer. Invade. The electrical resistance value (R) between the two electrodes was measured by a tester (TR-684 manufactured by Advantest Corporation).
6), and expressed as a common logarithmic value (logR). Glass transition point: Measured at a temperature rising rate of 10 ° C./min using a differential thermal analyzer DSC50 manufactured by Shimadzu Corporation. Static electricity application: Dry pellets are put into a melt extruder, a fine wire electrode is provided between the die of the extruder and the cooling drum, and a DC voltage of 10 KV is applied between the fine wire and the cooling drum. Then, it was determined whether or not an unsolidified sheet having a film-forming width of 0.3 m and a thickness of 1 mm when not stretched can be excellently formed at a cooling drum speed of 10 m / min. When the electrostatic adhesion is insufficient, the sheet surface may have a crease-like or wavy state (hereinafter referred to as "becco"). The flatness was measured by expressing the generation area of this solid as a ratio.

Example 1 13.7 Kg of NCM, 8.0 Kg of ethylene glycol, 3.5 g of manganese acetate tetrahydrate, 3.9 g of antimony trioxide were added with a stirrer, a rectification column and an N ₂ inlet pipe. In a reaction kettle, the atmosphere is replaced with N ₂ , and the temperature is gradually raised with stirring. When the liquid temperature reaches about 180 ° C., the reaction starts and methanol begins to flow out. Further, the liquid temperature was raised to 250 ° C., and the reaction was completed in about 4 hours. The oligomer after completion of the transesterification reaction was heated to 260 ° C., transferred to a polycondensation reaction kettle equipped with a stirrer, a distillation tube, a N ₂ introduction tube and a polymer discharge tube at the bottom of the kettle, and 7.5 g while stirring. Of magnesium acetate tetrahydrate, 3.5 g of trimethyl phosphate and 0.3 g of 2.5.6-trimethylbenzimidazole are added to the reaction kettle and the reaction system is evacuated. Gradually raise the vacuum to 0.5 mmHg, and finally set the liquid temperature to 2 mm.
Raise to 85 ° C. The melt viscosity was read by the torque meter attached to the stirrer, and when the predetermined torque value was reached, the reaction was terminated. It took about 3.5 hours. The reaction system is returned to normal pressure with N ₂ , and further pressurized to take out the polymer from the discharge pipe at the bottom of the kettle. The taken out strand polymer is cooled in a water bath and cut into pellets. The pellets were dried and subjected to a physical property measurement and an electrostatic adhesion test during film formation (evaluated by the flatness of the base). The transparency of the biaxially stretched film exceeded the standard. Tables 1 and 2 show the composition and characteristics.

Examples 2 and 3 In Example 1, PEN was synthesized by changing the amounts of magnesium acetate tetrahydrate and trimethyl phosphate added. The other additives, the amount added and the reaction method were exactly the same as in Example 1. Tables 1 and 2 show the composition and characteristics.

Example 4 After transferring the oligomer whose transesterification reaction was completed in Example 1 to a polycondensation kettle, 3.5 g of trimethyl phosphate and 0.5 kg of ethylene glycol of sodium 5-sulfoisophthalate were stirred with stirring. An ester (hereinafter referred to as SSIE) was added and a polycondensation reaction was carried out in the same manner as in Example 1. In this example, magnesium acetate and the imidazole compound were not added. Tables 1 and 2 show the composition and characteristics.

Example 5 1.09 Kg of dimethyl terephthalate, 12.3 Kg of NCM 8.4 Kg of ethylene glycol and 3.5 g of manganese acetate tetrahydrate were placed in a reaction kettle and stirred to 2
Heat gradually to 50 ° C. The transesterification reaction proceeded while removing by-produced methanol from the rectification column, and a predetermined amount of methanol flowed out in about 4.5 hours to complete the transesterification reaction. The reaction completed liquid is transferred to a polycondensation kettle heated to 250 ° C. 5.0 g of antimony trioxide, 14.5 g of magnesium acetate tetrahydrate, 5.0 g of trimethyl phosphate and 0.4 g of 2.5.6-trimethylbenzimidazole were added, and the reaction system was gradually evacuated to the final state. The target is 0.5 mmHg. The temperature of the reaction solution is also raised and finally heated to 280 ° C. When the predetermined torque value was reached, the polycondensation reaction was terminated. It took about 3.5 hours. The polymer was pelletized as in Example 1 and various properties were measured. Further, when the support of the present invention was coated with an undercoat layer, a backcoat layer and a photographic emulsion layer described in Examples 1 to 7 of Kokai Giho No. 94-6023, it was confirmed that there was no particular problem. Tables 1 and 2 show the composition and characteristics.

Examples 6 and 7 Transesterification was carried out by replacing 15 mol% and 30 mol% of NCM of Example 1 with dimethyl terephthalate. The kind and the addition amount of the catalyst, the kind and the amount of the other additives, the reaction method and the like were the same as in Example 1. Tables 1 and 2 show the composition and characteristics.

Comparative Examples 1 to 3 Of Example 1, magnesium acetate tetrahydrate and 2.5.6-trimethylbenzimidazole were added in different amounts, and the reaction was performed in exactly the same manner as in Example 1. Tables 1 and 2 show the composition and characteristics.

Table 1 Acid component, catalyst and additive composition NCM TA component Mn Mg P TMI SSIE Charge amount Charge amount Residual amount Residual amount Residual amount Charge amount Example 1 100 mol% -55ppm 60ppm 20ppm 22ppm-Example 2 100 mol% -55ppm 55ppm 18ppm 22ppm-Example 3 100mol% -55ppm 80ppm 25ppm 22ppm-Example 4 100mol% -55ppm-20ppm-2.5mol% Example 5 90mol% 10mol% 60ppm 65ppm 20ppm 23ppm-Implementation Example 6 85 mol% 15 mol% 60ppm 65ppm 20ppm 23ppm-Example 7 70 mol% 30mol% 57ppm 65ppm 20ppm 23ppm-Comparative Example 1 100mol% -55ppm-20ppm --- Comparative Example 2 100mol% -55ppm 55ppm 25ppm- -Comparative Example 3 100 mol% -55ppm 40ppm 20ppm 20ppm-1.NCM: 2,6-naphthalenedicarboxylic acid dimethyl ester, 2.TA component: Referred to as terephthalic acid in Example 5 and as dimethyl terephthalate in Examples 6 and 7. 3.Mn: Manganese element remaining in polyester 4.Mg Magnesium elements remaining in the polyester 5.P: phosphorus element remaining in the polyester 6.TMI: 2,5,6- trimethyl benzimidazole 7.SSIE: 5- sulfonium isophthalate sodium glycol ester

Table 2 Properties of Polyester Intrinsic Viscosity Pellet logR Glass Transition Point Sheet Flatness Film Forming Speed b Value (Tg) (% Becq Occurrence%) m / min Example 1 0.584 2.0 6.6 120 ° C. 2 40 Example 2 0.575 1.85 6.8 119 ℃ 3 30 Example 3 0.580 1.95 6.7 120 ℃ 0 100 Example 4 0.525 2.5 6.7 100 ℃ 0 85 Example 5 0.661 2.5 6.2 115 ℃ 0 95 Example 6 0.585 1.95 6.6 112 ℃ 0 70 Example 7 0.610 1.9 6.6 105 ℃ 1050 Comparative Example 1 0.576 1.8 8.1 117 ℃ 53 50 Comparative Example 2 0.580 1.85 7.5 119 ℃ 45 50 Comparative Example 3 0.570 2.0 7.3 120 ℃ 43 50

[0024]

EFFECT OF THE INVENTION A polyester with little coloring was obtained.
Further, at the time of melt film formation, electrostatic adhesion of polyester to the cooling drum was improved, and as a result, high-speed melt film formation became possible. Further, it is possible to provide a polyester photographic support having a small thickness, good transparency, and little coloring.

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Claims (8)

[Claims] 1. A polyester having a melt electric resistance value (logR) of 6.0 or more and less than 7.0. 2. A method for producing a polyester support, which comprises subjecting a polyester obtained by polycondensation reaction of an aromatic dicarboxylic acid diester and a diol by transesterification reaction to an electrostatic application method to produce a polyester support, which is usually used in a molten state at 300 ° C. The melting electric resistance value expressed by logarithm is 6.0 or more and 7.0.
A method for producing a polyester photographic support, which comprises subjecting the polyester, which is less than 1%, to film formation and stretching by an electrostatic application method. 3. The method for producing a polyester photographic support according to claim 2, wherein the film-forming stretching speed of the support is 20 m / min or more and 120 m / min or less. 4. The method for producing a polyester photographic support according to claim 2, wherein the thickness of the support in the unstretched film is 0.45 mm or more and 2.5 mm or less. 5. The film-forming width of the support when it is not stretched is 0.2 m.
It is above 3 m or less, The manufacturing method of the polyester photographic support of Claims 2-4 characterized by the above-mentioned. 6. The polyester-based photograph according to claim 2, wherein the polycondensation reaction is carried out after the glycol-soluble metal salt compound and the nitrogen atom-containing heterocyclic compound are added by the start of the polycondensation reaction. For manufacturing a support for use. 7. The method for producing a polyester photographic support according to claim 2, wherein the aromatic dicarboxylic acid diester is dimethyl-2,6-naphthalate. 8. The polyester is polyethylene-2,6.
A method for producing a polyester photographic support according to claim 7, which is naphthalate.