JPH09208719A - Polyethylene naphthalate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biaxially oriented polyethylene naphthalate film equipped with excellent transparency, hue, thermal stability and curling property for winding tendency simultaneously, and especially useful as a photographic sensitive material. SOLUTION: This biaxially oriented polyethylene naphthalate film consists of a polyethylene naphthalate containing naphthalene dicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, and elements of cobalt and phosphorus originated from a cobalt compound and a phosphorus compound respectively in a ratio of satisfying equations (I) and (II) simultaneously, and the haze of the biaxially oriented film is <=2.0% and yellow index (YID) thereof is <=5. Equation (I); 0. 5<=Co<=2.0, Equation (II); 0.3<=P/Co<=2.0 Where, Co expresses a number of modls of cobalt element per 10<6> g acid component. and P expresses a number of mols of phosphorus element per 10<6> g acid component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene naphthalate film, and more particularly, a polyethylene naphthalate film having excellent transparency, hue, thermal stability and curl curl, and particularly useful as a photographic light-sensitive material. Regarding

[0002]

2. Description of the Related Art Conventionally, triacetate film has been widely used as a base film used in a photographic light-sensitive material. Since this triacetate film uses an organic solvent in its manufacturing process, there are safety and environmental problems. In addition, there is a problem that mechanical strength and dimensional stability are limited.

For this reason, a part of polyethylene terephthalate film has come to be used as an alternative material. However, since curling curl remains strongly, handleability after development processing is poor and its range of use is limited. There is.

On the other hand, JP-A-53-146773
Japanese Patent Application Laid-Open No. 1-244446 proposes modified polyethylene terephthalate films having improved water vapor permeability and improved water content.
Although it is effective in reducing curl curl,
The dimensional stability was deteriorated due to moisture absorption, and the deformation of the end surface of the film was increased due to a decrease in glass transition temperature.

Particularly, in recent years, the use of photographic light-sensitive materials has been diversified, and for example, the speed of film transport at the time of photographing and the downsizing of photographing apparatuses have been advanced, and they are excellent as a film for photographic light-sensitive materials. In addition to curl elimination, performance such as strength, dimensional stability and adaptability for thinning has been demanded. For these requirements, triacetate film,
Also, a film for a photographic light-sensitive material having excellent properties, which cannot sufficiently correspond to the modified polyethylene terephthalate film, is desired.

[0006]

An object of the present invention is to provide a polyethylene naphthalate film which has excellent transparency, hue, thermal stability and curl resistance against curling, and is particularly useful as a photographic light-sensitive material. Especially.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
According to the present invention, a biaxially oriented film composed of polyethylene naphthalate having naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein the polyethylene naphthalate is an element of cobalt derived from a cobalt compound. , A phosphorus element derived from a phosphorus compound are contained in a ratio satisfying the following formulas and at the same time, and the haze of the biaxially oriented film is 2.0% or less, and the yellow index (Y
Achieved by a polyethylene naphthalate film characterized by an _ID ) of 5 or less.

[0008]

[Number 2] in 0.5 ≦ Co ≦ 2.0 ... 0.3 ≦ P / Co ≦ 2.0 ... ( wherein, Co is the number of moles of the acid component 10 ⁶ per g of cobalt element, P is the phosphorus The number of moles per 10 ⁶ g of the acid component is shown.)

In the present invention, the acid component of polyethylene naphthalate is mainly composed of naphthalenedicarboxylic acid. Examples of this naphthalene dicarboxylic acid include 2,
Examples thereof include 6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid. Of these, 2,6-naphthalenedicarboxylic acid is particularly preferable. When the main component of the acid component is not naphthalene dicarboxylic acid, for example, the curling property of the film becomes poor, which is not preferable.

Other acid components include aromatic dicarboxylic acids (eg, terephthalic acid, isophthalic acid, diphenylethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, anthracenedicarboxylic acid, etc. ); Aliphatic dicarboxylic acids (eg, adipic acid, sebacic acid, etc.); Alicyclic dicarboxylic acids (eg, cyclohexane-1,4-dicarboxylic acid, etc.) and the like. The proportion of these other acid components is preferably 20 mol% or less, more preferably 10 mol% or less, based on the total acid components.

In the present invention, the glycol component of polyethylene naphthalate is mainly composed of ethylene glycol.

Other glycol components include aliphatic glycols (eg, polymethylene glycol having 3 to 10 carbon atoms such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol). Etc.); Aromatic diol (eg hydroquinone, resorcin, 2,2-bis (4-hydroxyphenyl) propane etc.); Polyalkylene glycol (polyoxyalkylene glycol) (eg polyethylene glycol, polypropylene glycol, polytetramethylene glycol etc.) And the like. The proportion of these other glycol components is preferably 20 mol% or less, more preferably 10 mol% or less, based on the total glycol components.

The polyethylene naphthalate used in the present invention may be an aromatic oxyacid such as hydroxybenzoic acid or an oxycarboxylic acid such as an aliphatic oxyacid such as ω-hydroxycaproic acid unless the effects of the present invention are impaired. It is also possible to copolymerize or bond the component derived from the above at a ratio of 20 mol% or less with respect to the total amount of the dicarboxylic acid component and the oxycarboxylic acid component.

Further, in the polyethylene naphthalate of the present invention, an amount of, for example, 2 mol% or less with respect to the total acid component, is used as long as the amount is in a substantially linear range and does not impair the effects of the present invention. It is also possible to copolymerize a trifunctional or higher functional polycarboxylic acid or polyhydroxy compound such as trimellitic acid or pentaerythritol.

The polyethylene naphthalate in the present invention is preferably produced by reacting a lower alkyl ester of naphthalene dicarboxylic acid with ethylene glycol, and in this reaction, a part of the lower alkyl ester of naphthalene dicarboxylic acid (for example, 20 mol) is used. % Or less) may be replaced with another acid component, and a part of the glycol (for example, 20 mol% or less) may be replaced with another glycol component.

Examples of the lower alkyl ester of naphthalenedicarboxylic acid include dimethyl ester, diethyl ester and dipropyl ester, and dimethyl ester is particularly preferable.

[0017] In the production of polyethylene naphthalate in the invention, in (melt) reaction of a lower alkyl ester and ethylene glycol naphthalene dicarboxylic acid, firstly, with respect to the acid component 10 ⁶ g, element content of cobalt 0. A soluble cobalt compound is added to the reaction system in an amount of 5 to 2.0 mol to carry out a transesterification reaction. This amount is preferably 1.0 to 1.5 mol.

When the amount of the cobalt compound added to the acid component as the transesterification catalyst exceeds the above-mentioned 2.0 mol, the surface flatness when formed into a film is deteriorated due to the effect of the precipitated particles due to the catalyst residue, and as a result, The transparency of the film becomes poor, which is not preferable. On the other hand, this amount is 0.5
If it is less than the molar amount, not only the transesterification reaction becomes insufficient, but also the subsequent polymerization reaction is slow, which is not preferable.

Then, when the transesterification reaction is substantially completed, a phosphorus compound is added in order to deactivate a part or all of the catalytic activity of the cobalt compound, and the amount of the phosphorus compound (mol / acid component) is added. 10 ⁶ g) has a molar ratio [P / Co] of the added amount of the cobalt compound to 0.3-
It is preferable to satisfy that it is 2.0. A particularly preferred molar ratio is 0.7 to 1.6. This molar ratio is 2.0
If it exceeds, the surface flatness is deteriorated and the transparency is lowered when formed into a film due to the influence of the precipitated particles due to the phosphorus catalyst residue, which is not preferable. On the other hand, if the molar ratio is less than 0.3, the thermal stability of polyethylene terephthalate deteriorates due to the activity of the cobalt compound that is not deactivated by the phosphorus compound, and the hue becomes poor when formed into a film, which is not preferable.

The cobalt compound is not particularly limited, but oxides, chlorides, carbonates, carboxylates and the like are preferable, and acetate, that is, cobalt acetate is particularly preferable. Also,
Examples of the phosphorus compound include trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, phosphoric acid and the like. Preferably it is trimethyl phosphate.

Then, the reaction product is subjected to a melt polycondensation reaction to obtain a polymer. This polycondensation reaction is usually carried out under reduced pressure using a polycondensation reaction catalyst. It may also be combined with a solid-state polymerization reaction. As the catalyst, those known in the art can be used, but antimony compounds and germanium compounds are particularly preferable. The antimony compound is preferably an oxide, particularly antimony trioxide. The germanium compound is preferably a carboxylate, particularly germanium acetate.

The polyethylene naphthalate in the present invention requires additives such as lubricants, pigments, dyes, antioxidants, light stabilizers and light-shielding agents as long as the surface flatness and thermal stability are not impaired. It can also be contained according to.

In the present invention, the haze of the biaxially oriented film made of polyethylene naphthalate is 2.0% or less. It is preferably 1.5% or less, more preferably 1.
0% or less. When the haze exceeds 2.0%, the transparency of the film is lowered, which is not preferable when used as a film for a photographic light-sensitive material, for example.

Further, the yellow index (Y _ID ) of the biaxially oriented film is 5 or less. If this Y _ID exceeds 5, it is not preferable because the color tone becomes uneven when used as a color film. In the present invention, the cobalt compound is used as the transesterification reaction catalyst, and the amount of the cobalt element is set to 0.5 to 2.0 mol (per 10 ⁶ g of the acid component) in order to make this Y _ID 5 or less. It is a necessary means. That is, when formed into a film, the absorption of light at 400 to 500 nm is exhibited by a cobalt compound having a smaller light absorption than other transesterification reaction catalysts (such as manganese acetate).

In the present invention, a known method can be used as a method for producing the biaxially oriented film.
Using the above polyethylene naphthalate, for example, the melting point (T
(m: ° C.) to (Tm + 60) ° C., the polymer is melt extruded and rapidly cooled to have an intrinsic viscosity of 0.35 to 0.9 dl / g.
To obtain a non-stretched film of (Tg-10) to (Tg + 5) in the uniaxial direction (longitudinal direction or transverse direction).
0) ° C. (however, Tg: glass transition temperature of polyethylene naphthalate) is stretched at a draw ratio of 2 to 5 times, and then in a direction perpendicular to the stretching direction (in the case where the first stage stretching is the longitudinal direction, two stages are used). Tg (° C) to (Tg
It is stretched at a temperature of +50) ° C. at a draw ratio of 2 to 5 times.

After that, a heat setting process is further performed. This heat setting treatment is preferably performed in the range of 200 to 250 ° C. If the heat setting temperature is lower than 200 ° C, the film is liable to cause layer peeling (delamination) and the isolated portion is whitened. For example, layer peeling at the time of perforation hole formation as a photographic film, contact with metal etc. This is not preferable because it causes problems such as scratch growth.
On the other hand, when the heat setting temperature is higher than 250 ° C., the film is whitened due to excessive crystallization of the film, resulting in poor transparency, which is not preferable.

The thickness of the biaxially oriented film can be appropriately selected depending on the mode of use as a photographic light-sensitive material, but is 50 to 20.
0 μm, and more preferably 70 to 150 μm.

Since the biaxially oriented polyethylene naphthalate film of the present invention has specific transmission characteristics by specifying the contents of the cobalt element and the phosphorus element, it has excellent transparency, hue, surface flatness and curl. It has curl,
It is particularly useful as a film for photographic light-sensitive materials.

[0029]

The present invention will be described more specifically with reference to the following examples. In the examples, "parts" means parts by weight.
Further, the measurement of each characteristic value in the embodiment is performed by the following method.

(1) Haze of Film (Haze) According to JIS-K6714, the haze of the film is determined by an integrating sphere type HTR meter manufactured by Nippon Seimitsu Optical Co., Ltd.

(2) Yellow Index (Y _ID ) of Film Using a color difference meter SZ-Σ90 manufactured by Nippon Denshoku Industries Co., Ltd., the Y _ID of the film is calculated by the following formula.

[0032]

(Equation 3)

Here, X, Y, and Z are tristimulus values of light defined by the international CIE standard.

[Example 1] 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester and ethylene glycol 6
0 part was subjected to a transesterification reaction according to a conventional method using 0.03 part (1.23 mol) of cobalt acetate tetrahydrate as a transesterification catalyst, and then 0.023 part (1.64 parts) of trimethyl phosphate. Mol) was added to substantially terminate the transesterification reaction.

Further, 0.024 part of antimony trioxide (0.
(82 mol) was added, and then polycondensation reaction was carried out in a usual manner under high temperature and high vacuum to give an intrinsic viscosity of 0.62 dl (measured with a phenol / tetrachloroethane mixed solvent at 35 ° C.).
/ G of polyethylene naphthalate was obtained.

The polyethylene naphthalate pellets were dried at 180 ° C. for 3 hours and then fed to the extruder hopper,
Melt at a melting temperature of 300 ℃,
The film was extruded onto a rotary cooling drum having a surface temperature of 40 ° C. through a slit-shaped die to obtain an unstretched film. The unstretched film thus obtained is preheated at 120 ° C. and further stretched 3.0 times by heating with one IR heater having a surface temperature of 900 ° C. from above 15 mm between low speed and high speed rolls. Then, it was supplied to a stenter and stretched 3.3 times in the transverse direction at 140 ° C. The obtained biaxially oriented film is 23
The film was heat set at a temperature of 0 ° C. for 10 seconds to obtain a polyethylene naphthalate biaxially oriented film having a thickness of 85 μm. The intrinsic viscosity of this film was 0.60 dl / g.

The biaxially oriented film obtained was heat-treated at 115 ° C. for 2 days and the film characteristics were measured. As shown in Table 1, the results were good.

Comparative Examples 1 to 4 Example 1 was repeated except that the amounts of cobalt acetate and trimethyl phosphate were changed to those shown in Table 1. Each of the obtained biaxially oriented films had poor film properties, and Comparative Example 4
However, the transesterification reaction was insufficient and a film could not be obtained.

[0039]

[Table 1]

[0040]

According to the present invention, excellent transparency, hue,
It is possible to provide a polyethylene naphthalate biaxially oriented film which has both thermal stability and curl curl property and is particularly useful as a photographic light-sensitive material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 7:00 C08L 67:00

Claims (4)

[Claims] 1. A biaxially oriented film composed of polyethylene naphthalate containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein the polyethylene naphthalate contains a cobalt element derived from a cobalt compound. It contains a phosphorus element derived from a phosphorus compound in a ratio that simultaneously satisfies the following formulas and, and the haze of the biaxially oriented film is 2.0% or less, and the yellow index (Y _ID ) is 5: A polyethylene naphthalate film characterized by being: 0.5 ≦ Co ≦ 2.0 ... 0.3 ≦ P / Co ≦ 2.0 (wherein, Co is the number of moles per 10 ⁶ g of the acid component of the cobalt element, and P is the phosphorus element). The number of moles per 10 ⁶ g of the acid component is shown.) 2. The polyethylene naphthalate film according to claim 1, wherein the polyethylene naphthalate is a polyethylene naphthalate produced by reacting a lower alkyl ester of naphthalene dicarboxylic acid with ethylene glycol. 3. The polyethylene naphthalate film according to claim 1, wherein the naphthalenedicarboxylic acid is 2,6-naphthalenedicarboxylic acid. 4. The polyethylene naphthalate film according to claim 1, which is a base film for a photographic light-sensitive material.