JP2003160718A - Polyester composition and biaxially-oriented polyester film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition excellent in thermal resistance and with less foreign matter, especially suitable for applying to magnetic materials use or capacitor use. <P>SOLUTION: This polyester composition comprises a polyester (A), a polyimide (B) and a terminal cross-linker (C), where the amount of terminal carboxy group is 1-45 equivalent/10<SP>6</SP>g, and the metal content is 3-450 ppm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester composition having excellent heat resistance and containing less foreign matter. Such polyester compositions include, for example, resin molded product applications, electric / electronic component-related applications, building material sector applications, automobile part applications,
It is applicable to a wide range of fields such as magnetic recording medium films, packaging material films, and capacitor films.

[0002]

2. Description of the Related Art Polyester is excellent in crystallinity, strength, chemical resistance and transparency and is used in various applications such as extrusion molded products, fibers, bottles and films. Among them, in film applications, due to their excellent mechanical properties and economical efficiency, they are used in the fields of magnetic recording material films, agricultural films, packaging films, building material films, condenser films and the like.

However, a film made of a polyester alone has insufficient heat resistance and thermal dimensional stability depending on the intended use, and has a limit in application to films for various industrial materials including magnetic material applications and capacitor applications. Therefore, in recent years, in order to improve the heat resistance of the polyester film, a method of blending polyester with another heat resistant resin has been studied.

In particular, regarding the blend of polyester and polyimide resin, which is related to the present invention, it is disclosed in the literature that the glass transition temperature, which is an index of heat resistance, increases as the polyimide resin fraction increases. (For example, US Pat. No. 4,141,927, “JOURNAL o
f APPLIED POLYMER SCIENCE
48, 935-937 (1993) "," Macrom
olecules 28 2845-2851 (199
5), POLYMER, 38, 4043-4048 (1
997) "etc.).

However, the composition composed of polyester and polyimide is excellent in thermal dimensional stability near the glass transition temperature (100 to 120 ° C.) as compared with the case of using the polyester alone, but the composition at around 150 to 200 ° C. There is a problem that mechanical long-term heat resistance at high temperature is not sufficient.

On the other hand, studies have also been conducted to improve the hydrolysis resistance of polyester. For example, JP-A-11-34
JP 048, JP 3110633, etc. describe that hydrolysis resistance is improved by adding a crosslinking agent or the like to polyester.

[0007]

However, according to the studies by the present inventors, the composition obtained when the above-mentioned cross-linking agent was added to a polyester / polyimide blend system, kneaded and melt-extruded was carried out. Since a large amount of foreign matter is generated therein, there is a problem that it is not possible to obtain a composition that has both long-term heat resistance and low foreign matter.

An object of the present invention is to solve the above problems and provide a polyester composition having excellent heat resistance and containing less foreign matter.

[0009]

The present invention comprises a polyester (A), a polyimide (B) and a terminal cross-linking agent (C), and has a carboxyl end group amount of 1 to 45 equivalents / 10 ⁶ g,
The main point is a polyester composition having a metal content of 3 to 450 ppm.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester (A) used in the present invention is not particularly limited, but ethylene terephthalate, ethylene-2,6-naphthalate, propylene terephthalate, butylene terephthalate, hexamethylene terephthalate, cyclohexane dimethylene terephthalate, propylene. -2,6-naphthalate, butylene-
Polyesters containing at least one structural unit selected from 2,6-naphthalate, hexamethylene-2,6-naphthalate, cyclohexanedimethylene-2,6-naphthalate units and the like as a main constituent component are preferable. Among them, the ethylene terephthalate unit is 80mo
1% or more of polyethylene terephthalate-based polyester (polyethylene terephthalate (hereinafter referred to as PET)) and / or polyethylene-containing ethylene-2,6-naphthalate unit as at least a main constituent
2,6-naphthalate polyester (polyethylene-
2,6-naphthalate (hereinafter referred to as PEN) is particularly preferable because it has excellent kneadability with the polyimide (B).

On the other hand, the polyimide (B) used in the present invention is preferably, for example, one containing a structural unit represented by the following general formula.

[0012]

[Chemical 1] In the above formula, Ar is an aromatic group having 6 to 42 carbon atoms, R is a divalent aromatic group having 6 to 30 carbon atoms, and a fat having 2 to 30 carbon atoms. Group 4
A divalent organic group selected from the group consisting of alicyclic groups having 30 carbon atoms.

In the above general formula, Ar is, for example,

[0014]

[Chemical 2]

[0015]

[Chemical 3] Can be mentioned. As R, for example,

[0016]

[Chemical 4]

[0017]

[Chemical 5] Can be mentioned.

These may be present in the polymer chain alone or in combination of two or more within the range that does not impair the effects of the present invention.

The polyimide (B) used in the present invention is not particularly limited, but as a preferable example from the viewpoint of melt moldability with the polyester (A) and handleability, for example, polyimide represented by the following general formula: An example is polyetherimide, which is a polymer that is a structural unit containing an ether bond as a constituent.

[0020]

[Chemical 6] However, in the above formula, R ₁ is a divalent organic group selected from the group consisting of a divalent aromatic or aliphatic group having 2 to 30 carbon atoms and an alicyclic group, and R ₂ Is a divalent organic group similar to R above.

Examples of R ₁ and R ₂ include aromatic groups represented by the following formula group:

[0022]

[Chemical 7] Can be mentioned.

In the present invention, when a polyether imide having a glass transition temperature of 350 ° C. or lower, more preferably 250 ° C. or lower is used, the effects of the present invention are easily obtained, and compatibility with the polyester (A), melt moldability, etc. From the viewpoint, 2,2-bis [4- (2, having a structural unit represented by the following formula:
A condensate of 3-dicarboxyphenoxy) phenyl] propane dianhydride and m-phenylenediamine or p-phenylenediamine is preferable.

[0024]

[Chemical 8] This polyetherimide is "Ultem" (registered trademark)
It is available from GE Plastics, Inc.

The above polyimide can be manufactured by a known method. For example, a group consisting of a tetracarboxylic acid and / or an acid anhydride thereof as a raw material capable of inducing Ar and an aliphatic primary diamine and / or an aromatic primary diamine as a raw material capable of inducing R. It can be obtained by dehydration-condensation of one or more compounds selected from the following. Specifically, a method of obtaining a polyamic acid and then subjecting it to ring closure by heating can be exemplified. Alternatively, a method in which an acid anhydride and a chemical ring-closing agent such as pyridine or carbodiimide are used for chemical ring closure, or the tetracarboxylic acid anhydride and the diisocyanate capable of inducing R are heated to decarboxylate and polymerize A method etc. can be illustrated.

The tetracarboxylic acid used in the above method is, for example, pyromellitic acid, 1, 2, 3, 4
-Benzene tetracarboxylic acid, 3, 3 ', 4, 4'-
Biphenyl tetracarboxylic acid, 2, 2 ', 3, 3'-
Biphenyl tetracarboxylic acid, 3, 3 ', 4, 4'-
Benzophenone tetracarboxylic acid, 2, 2 ', 3,
3'-benzophenone tetracarboxylic acid, bis (2,3
-Dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, 1,1'-bis (2,
3-dicarboxyphenyl) ethane, 2,2'-bis (3,4-dicarboxyphenyl) propane, 2,
2'-bis (2,3-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) ether, bis (2,3-dicarboxyphenyl) ether, bis (3,4-dicarboxyphenyl) sulfone Bis (2,3-dicarboxyphenyl) sulfone, 2,3,6,7-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid Acids such as 2,2'-bis [(2,3-dicarboxyphenoxy) phenyl] propane and / or acid anhydrides thereof are used.

As the diamine, for example, benzidine, diaminodiphenylmethane, diaminodiphenylethane, diaminodiphenylpropane, diaminodiphenylbutane, diaminodiphenylether, diaminodiphenylsulfone, diaminodiphenylbenzophenone,
o, m, p-phenylenediamine, tolylenediamine, xylenediamine and the like, and aromatic primary diamines having a hydrocarbon group of the exemplified aromatic primary diamine as a structural unit, ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1,6-hexamethylenediamine, 1,8-octamethylenediamine, 1,9
-Nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12
-Dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-cyclohexanediamine,
1,4-cyclohexanediamine, 1,4-cyclohexanedimethylamine, 2-methyl-1,3-cyclohexanediamine, isophoronediamine and the like, and hydrocarbon groups of these exemplified aliphatic and alicyclic primary diamines as structural units. Examples thereof include aliphatic and alicyclic primary diamines.

As the terminal cross-linking agent (C), compounds having a carbodiimide group, an epoxy group or an oxazoline group are preferable.

Preferred monofunctional carbodiimide compounds include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide,
t-butyl isopropyl carbodiimide, diphenyl carbodiimide, di-t-butyl carbodiimide, di-β
-Naphthylcarbodiimide and the like can be exemplified, and among these, dicyclohexylcarbodiimide,
Alternatively, diisopropylcarbodiimide is preferred.

As the polyfunctional carbodiimide,
Carbodiimides having a degree of polymerization of 3 to 15 are preferable, and specifically, 1,5-naphthalenecarbodiimide and 4,4′-
Diphenylmethane carbodiimide, 4,4'-diphenyldimethylmethane carbodiimide, 1,3-phenylene carbodiimide, 1,4-phenylene diisocyanate, 2,4-tolylene carbodiimide, 2,6-tolylene carbodiimide, 2,4-tolylene carbodiimide And 2,6-tolylenecarbodiimide, hexamethylenecarbodiimide, cyclohexane-1,4-carbodiimide, xylylenecarbodiimide, isophoronecarbodiimide, isophoronecarbodiimide, dicyclohexylmethane-4,4'-carbodiimide, methylcyclohexanecarbodiimide, tetramethylxylyl Lencarbodiimide, 2,6-diisopropylphenylcarbodiimide, 1,3,5-triisopropylbenzene-2,
4-carbodiimide and the like can be exemplified, but of course, it is not limited to the above compounds.

Further, preferred examples of the epoxy compound include a glycidyl ester compound and a glycidyl ether compound.

Specific examples of the glycidyl ester compound include glycidyl benzoate, t-Bu-glycidyl benzoate, glycidyl P-toluate, cyclohexanecarboxylic acid glycidyl ester, pelargonic acid glycidyl ester, stearic acid glycidyl ester, and laurin. Acid glycidyl ester, palmitic acid glycidyl ester, behenic acid glycidyl ester, versatic acid glycidyl ester, oleic acid glycidyl ester, linoleic acid glycidyl ester, linoleic acid glycidyl ester, behenolic acid glycidyl ester, stearolic acid glycidyl ester, terephthalic acid diglycidyl ester , Isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphthalene dicarboxylic acid diester Lysidyl ester, methyl terephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, cyclohexanedicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester, succinic acid diglycidyl ester, sebacic acid diglycidyl ester , Dodecanedioic acid diglycidyl ester, octadecane dicarboxylic acid diglycidyl ester, trimellitic acid triglycidyl ester, pyromellitic acid tetraglycidyl ester, etc., and these may be used alone or in combination.
More than one species can be used.

Specific examples of the glycidyl ether compound include phenylglycidyl ether, O-phenylglycidyl ether, 1,4-bis (β, γ-epoxypropoxy) butane, and 1,6-bis (β, γ). -Epoxypropoxy) hexane, 1,4-bis (β, γ-epoxypropoxy) benzene, 1- (β, γ-epoxypropoxy) -2-ethoxyethane, 1- (β, γ-epoxypropoxy) -2- Benzyloxyethane, 2,2-bis- [р- (β, γ-epoxypropoxy) phenyl] propane and 2,2-bis- (4-hydroxyphenyl) propane and 2,2-bis- (4-hydroxyphenyl) ) Bisglycidyl polyethers obtained by the reaction of bisphenols such as methane with epichlorohydrin, and the like. These may be used alone or in combination of two or more. It is possible to have.

The oxazoline compound is preferably a bisoxazoline compound, specifically, 2,2'-
Bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4,4-dimethyl-2-oxazoline), 2,2'-bis (4- Ethyl-2-oxazoline), 2,2'-bis (4,4 '
-Diethyl-2-oxazoline), 2,2'-bis (4
-Propyl-2-oxazoline), 2,2'-bis (4
-Butyl-2-oxazoline), 2,2'-bis (4-
Hexyl-2-oxazoline), 2,2'-bis (4-
Phenyl-2-oxazoline), 2,2'-bis (4-
Cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline), 2,2'-p-
Phenylene bis (2-oxazoline), 2,2'-m-
Phenylene bis (2-oxazoline), 2,2'-o-
Phenylene bis (2-oxazoline), 2,2'-p-
Phenylene bis (4-methyl-2-oxazoline),
2,2'-p-phenylene bis (4,4-dimethyl-2
-Oxazoline), 2,2'-m-phenylenebis (4
-Methyl-2-oxazoline), 2,2'-m-phenylenebis (4,4-dimethyl-2-oxazoline),
2,2'-ethylenebis (2-oxazoline), 2,
2'-tetramethylene bis (2-oxazoline), 2,
2'-hexamethylenebis (2-oxazoline), 2,
2'-octamethylene bis (2-oxazoline), 2,
2'-decamethylene bis (2-oxazoline), 2,
2'-ethylenebis (4-methyl-2-oxazoline), 2,2'-tetramethylenebis (4,4-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis ( 2-oxazoline), 2,2'-cyclohexylene bis (2-oxazoline), 2,2'-
Examples thereof include diphenylene bis (2-oxazoline), and of these, 2,2′-bis (2-oxazoline) is most preferable from the viewpoint of reactivity with polyester. Further, the bisoxazoline compounds listed above may be used alone or in combination of two or more as long as the object of the present invention is achieved.

The content of the terminal crosslinking agent (C) is preferably 0.1 to 5% by weight based on the total weight of the resin. When the content of the terminal crosslinking agent (C) is 0.1% by weight or more, the heat resistance effect of the present invention is easily obtained, and when it is 5% by weight or less, the number of foreign matters can be kept small. preferable. A more preferable range is 0.2 to 2% by weight, and a most preferable range is 0.3 to 1% by weight.

In the polyester composition of the present invention, a plasticizer, a weather resistance agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, and a whitening agent are used as long as the effects of the present invention are not impaired. A compound such as an agent, a coloring agent, a conductive agent, and a crystal nucleating agent, inorganic particles, organic particles, or another kind of polymer may be added.

The polyester composition disclosed in the present invention is
It is essential that the amount of carboxyl end groups is 1 to 45 equivalents / 10 ⁶ g. This amount of carboxyl end groups is the sum of the amount of carboxyl end groups of the polyester molecule and the amount of carboxyl end groups of the polyimide molecule. When the amount of carboxyl end groups exceeds 45 equivalents / 10 ⁶ g, the carboxyl end groups exert a catalytic action for polyester decomposition, resulting in a polyester composition having poor heat resistance. Also,
In order to reduce the amount of the carboxyl terminal group to less than 1 equivalent / 10 ⁶ g, it is necessary to add the terminal crosslinking agent (C) excessively or to carry out solid phase polymerization for a long time, resulting in poor productivity. Not preferable. Further, the more preferable range of the amount of carboxyl terminal group is 5 to 45 equivalent / 10 ⁶ g, and the most preferable range is 10 to 40 equivalent / 10 ⁶ g.

Any method may be used as the method for controlling the amount of the carboxyl end group within the range of the present invention. As a particularly preferable method, the active group equivalent of the terminal cross-linking agent (C) is 1. The sum of the carboxyl terminal group amount of the polyester molecule and the carboxyl terminal group amount of the polyimide molecule is 1.
The method of making it 2 to 2 times is mentioned. Further, as another method, there is a method in which the obtained composition is processed into pellets, which is then subjected to heat treatment under high vacuum to carry out solid phase polymerization.

Further, it is essential that the polyester composition disclosed in the present invention has a metal content of 3 to 450 ppm. If the metal content exceeds 450 ppm,
A large amount of foreign matter is generated in the composition during the melt extrusion due to the reaction product of the polyester (A) or the polyimide (B), and it is difficult to use in the field where the surface property after molding is required. Further, if the metal content is less than 3 ppm, the amount of catalyst during polyester polymerization becomes too small and a long polymerization time is required, which is not preferable from the viewpoint of productivity. The more preferable range of the metal content is 20 to 3
00 ppm, most preferred range is 100-200 ppm
Is.

As a method of incorporating a metal atom into the polyester composition, an alkali metal such as lithium, sodium and potassium, an alkaline earth metal such as magnesium and calcium, and a compound containing a metal atom such as zinc and manganese, germanium. A method in which a compound consisting of, antimony, and titanium, specifically, lithium acetate, calcium acetate, magnesium acetate, manganese acetate, lithium chloride, manganese chloride and the like is charged into the extruder together with the raw material polymer is preferably used.

As the germanium compound, germanium dioxide, germanium oxide or hydroxide such as germanium hydroxide containing water of crystallization, or germanium alkoxide compound such as germanium tetramethoxide or germanium ethylene glycoloxide, phosphorus containing such as germanium phosphate Examples thereof include germanium compounds and germanium acetate.

Examples of the antimony compound include antimony trioxide and antimony acetate.

Examples of the titanium compound include oxides such as titanium dioxide, hydroxides such as titanium hydroxide, alkoxide compounds such as tetramethoxy titanate, tetraethoxy titanate and tetrabutoxy titanate, and glycolide compounds such as tetrahydroxyethyl titanate. ,
Examples thereof include compounds such as phenoxide compounds and acetates.

The amount of amino terminal groups of the polyester composition of the present invention is from the viewpoints of extrusion moldability, thermal decomposability and productivity.
0.2 to 20 equivalent / ton is preferable. More preferably 0.3 to 12 equivalents / ton, most preferably 0.4 to 6
Equivalent / ton.

The intrinsic viscosity of the polyester composition disclosed in the present invention is preferably 0.53 to 0.85 dl / g. When the intrinsic viscosity is 0.53 dl / g or more, a polyester composition excellent in heat resistance is likely to be obtained, and when the intrinsic viscosity is 0.85 dl / g or less, a polyester composition excellent in moldability is easily obtainable. Become. Moreover, the more preferable range of the intrinsic viscosity is 0.58 to 0.75 dl / g, and the most preferable range is 0.6 to 0.65.

The method for measuring the ratio of the polyester (A), the polyimide (B) and the terminal crosslinking agent (C) of the present invention is as follows:
The following method is preferably used. A composition comprising a polyester (A), a polyimide (B) and a terminal cross-linking agent (C) is dissolved in a suitable solvent such as hexafluoroisopropanol / chloroform to dissolve both, and a ¹ H nucleus NM is used.
R spectrum is measured. In the obtained spectrum, a peak corresponding to an aromatic proton in the polyester (A) (around 8.1 ppm in PET) and a polyimide (B)
The peak area intensity of each of the peaks corresponding to the protons belonging to the aromatic group belonging to the imide ring and the peaks corresponding to the protons belonging to the terminal cross-linking agent is determined, and the ratio and the number of protons are determined. The molar ratio is calculated from the above. Further, the weight ratio is calculated from the formula weight corresponding to the unit unit of the polymer.

The polyester composition of the present invention preferably has a single glass transition temperature (Tg). The glass transition temperature referred to in the present invention can be determined according to JIS K7121 from the heat flux gap at the time of temperature rise in differential scanning calorimetry. When it is difficult to make a determination only by the method of differential scanning calorimetry, a morphological method such as dynamic viscoelasticity measurement or microscopic observation may be used together. When determining the glass transition temperature by differential scanning calorimetry,
It is also effective to use a temperature modulation method or a high sensitivity method.

The amount of diethylene glycol contained in the polyester (A) used in the present invention is preferably 5% by weight or less from the viewpoint of improving heat resistance. More preferably 2
It is not more than 1% by weight, most preferably not more than 1% by weight.

The polyester composition of the present invention is molded by a known molding method such as extrusion molding, injection molding, compression molding, transfer molding and put into practical use.

Next, a method for producing a molded product from the polyester composition of the present invention will be described, but it goes without saying that the present invention is not limited to the following description. The polyester composition of the present invention is vacuum dried at 160 ° C. for 5 hours or more, then put into an injection molding machine and extruded at a cylinder temperature of 280 to 380 ° C., more preferably 300 to 350 ° C. The mold temperature is 50 to 100 ° C, more preferably 70 to 90 ° C.
The polyester composition of the present invention used for this molding is excellent in heat resistance, and has excellent surface smoothness when formed into a molded product due to a small amount of foreign matter, and can be used as a circuit board material, etc., and is very useful. Is.

The polyester composition of the present invention is formed into a film by a known film forming method such as melt extrusion film forming and solution cast film forming, and is put to practical use. In the case of a film, it may be a non-oriented film or a uniaxially or biaxially oriented film, but a biaxially oriented film is preferred.

Next, specific examples of the method for producing the biaxially oriented polyester film of the present invention will be described, but it goes without saying that the description is not limited thereto.

First, 40 to 60 parts by weight of polyester (A) and 60 to 40 parts by weight of polyimide (B) (total of the pellets of polyester (A), the pellets of polyimide (B) and the terminal crosslinking agent (C)) 100 parts by weight),
The terminal cross-linking agent (C) is mixed in a predetermined ratio, and dried at 160 ° C. under vacuum for 5 hours or more. The obtained dried product is mixed and supplied to a vent type twin-screw kneading extruder heated to 270 to 300 ° C. to perform melt extrusion to obtain a high-concentration polyimide / additive-containing pellet (a). The residence time at this time is preferably 0.5 to 10 minutes, more preferably 1 to 5 minutes.

The high-concentration polyimide / additive-containing pellets (a) thus obtained and polyester pellets obtained by a conventional method were mixed at a predetermined ratio and vacuum dried at 180 ° C. for 5 hours or more, and then the extruder was used. 280-320
The mixture is melt-extruded at a temperature of ℃, passed through a fiber-sintered stainless metal filter, and then discharged in a sheet form from a T-die. Further, this sheet is brought into close contact with a cooling drum having a surface temperature of 25 to 30 ° C. to be cooled and solidified to obtain a substantially non-oriented film.

Next, this unstretched film is biaxially stretched,
Orient biaxially. As a stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. In order to stretch under the optimal conditions, it is preferable to stretch in the range of the glass transition temperature (Tg) of the unstretched film to Tg + 50 ° C.

Here, a longitudinal stretching machine in which several rolls are arranged is used to stretch in the longitudinal direction by utilizing the peripheral speed difference of the rolls (MD stretching), and then transverse stretching is carried out by a stenter (TD). A biaxial stretching method called "stretching" will be described.

First, the unstretched film is (Tg) to (Tg
+50) (° C.) range, more preferably (Tg) to
It is heated with a heating roll group in the range of (Tg + 30) (° C.), and is 1.1 to 5.0 times in the longitudinal direction, preferably 1.5 to
MD stretching is performed by a method of stretching at 4.0 times, more preferably 2.0 to 3.5 times, and cooling with a cooling roll group at 20 to 50 ° C. Next, stretching in the width direction is performed using a stenter. The draw ratio is 2.0 to 6.0 times, preferably 3.0 to 5.5 times, and more preferably 4.0.
5.0 times, the temperature is in the range of (Tg) to (Tg + 50) (° C), more preferably (Tg) to (Tg + 30) (° C).
(TD stretching). If necessary, this stretched film is stretched under tension or while relaxing in the width direction,
The heat treatment is performed at 250 ° C., preferably 170 to 240 ° C., and more preferably 160 to 220 ° C.

After that, after cooling to room temperature, the film edge is removed to obtain a biaxially stretched film.

The biaxially oriented polyester film of the present invention can be preferably used for magnetic recording materials, capacitors, heat transfer ribbons, heat sensitive stencil printing base papers and the like.
Among them, it can be particularly preferably used as a heat resistant capacitor which requires heat resistance at high temperature.

(Physical property measuring method and effect evaluating method) The characteristic value measuring method and effect evaluating method are as follows.

(1) Long-term heat resistance Various film samples were cut into a size of 10 mm × 200 mm, placed in a gear oven, and heat-treated at 180 ° C. for a predetermined time. The elongation of the film before treatment was measured, and the elongation of the film after treatment was measured as a0 and a1, respectively, and a1 / a0 × 1
The elongation retention rate is calculated from 00 (%). Elongation retention rate is 5
The heat treatment time until the content became 0% or less was defined as the heat resistance time.

(2) Hydrolysis resistance Various film samples were cut into a size of 10 mm × 200 mm, and the film was placed in a pressure and humidity resistant oven at 140 ° C. and 80 ° C.
The wet heat treatment was performed for a predetermined time under the condition of% Rh. The elongation of the film before treatment is measured, and the elongation of the film after treatment is measured to be b0 and b1, respectively, and the elongation retention rate is calculated by b1 / b0 × 100 (%). The wet heat treatment time until the elongation retention rate became 50% or less was defined as the hydrolysis resistance time.

(3) Foreign matter (FE) A film sample is placed between orthogonal polarizing plates in which two polarizing plates are arranged orthogonally, white light is irradiated from one direction, and a magnifying glass (2 times) is used on the opposite side. Foreign matter in 1m x 1m (F
The number of E) was counted and used as the number of foreign matters.

(4) Gelation rate The pellets were freeze-ground using a freezer mill.
Vacuum dry the crushed pellets at 100 ° C for 40 minutes,
1 g (a) was precisely weighed and heat-treated in air at 300 ° C. for 2.5 hours. The treated pellet was dissolved in 50 ml of orthodichlorophenol, and a glass filter (3G3,
Weight = b0) and then washed with dichloromethane,
Vacuum dry. The weight (b1) of the glass filter was weighed, and the value (%) obtained from [(b1-b0) / a] × 100 was taken as the gelation rate.

(5) Intrinsic viscosity The value calculated from the following formula from the solution viscosity measured at 25 ° C. in orthochlorophenol was used. ηsp / C = [η] + K [η] ² · C where ηsp = (solution viscosity / solvent viscosity) −1,
C is the weight of dissolved polymer per 100 ml of solvent (g / 1
00 ml, usually 1.2), K is the Huggins constant (0.34
3). The solution viscosity and the solvent viscosity were measured using an Ostwald viscometer. The unit is [dl / g].

(6) Metal content in composition By fluorescent X-ray, germanium, antimony, titanium,
The intensity of each element amount of magnesium was quantified by comparing with the calibration curve obtained from each standard substance.

(7) Carboxyl end group content The polymer was dissolved in orthochlorocresol / chloroform (weight ratio 7/3) at 90 to 100 ° C., and the potential difference was measured with an alkali.

(8) Amino end group polymer 1 g is precisely weighed in a 100 ml beaker and dissolved in a chloroform / methanol / phenol mixed solvent. Then add a small amount of water and stir to 0.1mo
It quantified by performing potentiometric titration with 1-HCl. Automatic titrator: GT-05 type electrode manufactured by Mitsubishi Chemical: Glass electrode / reference electrode.

(9) Amount of diethylene glycol After amino decomposition of the sample, the amount of diethylene glycol was determined by gas chromatography.

[0070]

EXAMPLES The present invention will be described based on reference examples, examples and comparative examples.

Reference Example 1 <Polyimide (B-1)> 200 g of isophorone diisocyanate was added to 3000 ml of N-methyl-2-pyrrolidone (NMP) under a nitrogen atmosphere and stirred. Then
After adding 196 g of pyromellitic dianhydride to this solution at room temperature, the temperature is gradually raised. After that, when heated at 180 ° C. for 6 hours, the generation of carbon dioxide was completed, so the heating was stopped. This polymer solution was developed in water and washed, and then the polymer obtained here was dried to obtain polyimide (B-1). <Polyimide (B-2)> Under a nitrogen stream, 147 g (0.5 mol) of biphenyltetracarboxylic dianhydride was added to 300 g of N-methyl-2-pyrrolidone. To this solution, trans-1,4-diaminocyclohexane 5
What melt | dissolved 7 g (0.5 mol) in NMP17.6g was dripped, and it stirred at room temperature for 2 hours, and also at 50 degreeC for 4 hours, and obtained the polyamic-acid solution. After cooling the solution, water 50
It was charged into 0 ml to precipitate a polymer. The precipitated polymer was collected by filtration and heat-treated in nitrogen at 250 ° C. for 2 hours to obtain the target polyimide (B-2).

Reference Example 2 (Synthesis of carbodiimide compound) <Terminal cross-linking agent (C-1)> To 2442 g of isophorone diisocyanate, 258 g of di-n-butylamine was dropped and reacted at 50 ° C. for 1 hour to introduce a urea bond. Then, a carbodiimidization catalyst (3-methyl-1
-Phenyl-2-phosphorene-1-oxide) 24.4
g, and reacted at 180 ° C for 72 hours to give a yellow transparent urea-modified carbodiimide (carbodiimide group number = 10)
Got The obtained urea-modified carbodiimide was pulverized with a roll granulator after cooling. <Terminal cross-linking agent (C-2)> Tetramethyl xylylene diisocyanate 549 g and n-butyl isocyanate 4
9.5 g and carbodiimidization catalyst (3-methyl-1-
Phenyl-2-phosphorene-1-oxide) 5.99 g
Was reacted at 180 ° C. for 48 hours to obtain tetramethylxylylenecarbodiimide (terminal crosslinking agent (C-2)) (degree of polymerization = 10).

Reference Example 3 (epoxy compound) <Terminal cross-linking agent (C-3)> t-Bu-benzoic acid glycidyl ester "PES-10" epoxy equivalent 260 (manufactured by Fuso Chemical Industry Co., Ltd.) was used. <Terminal cross-linking agent (C-4)> Bisphenol A diglycidyl ether "Epicoat" 828 epoxy equivalent 190
(Okaka Shell Epoxy Co., Ltd.) was used.

Reference Example 4 (oxazoline compound) <Terminal cross-linking agent (C-5)> 1,4-phenylene bis (2
-Oxazoline) "BOX-220" (manufactured by Takemoto Yushi Co., Ltd.) was used.

Example 1 Pellets of polyethylene terephthalate (PET) obtained by a conventional method and having an intrinsic viscosity of 0.77 and using antimony trioxide (Sb) as a catalyst and containing magnesium acetate (Mg) ( 50 parts by weight) and polyetherimide (PEI) (intrinsic viscosity = 0.68, carboxyl end group amount = 12.5 equivalent / 10 ⁶ g, amino end group amount = 5.3 equivalent / 10 ⁶ g (GE plastic) Co., Ltd. (registered trademark: Ultem 1010)) (50 parts by weight) and a terminal crosslinking agent (C-1) (0.25 parts by weight) are mixed, and a co-rotating twin-screw kneading extruder (Toshiba Machinery Co., Ltd.) Company TEM-
Melt kneading was carried out using 35B). The kneading was performed at an extrusion temperature of 310 ° C., a residence time of 3.5 minutes, and a vent vacuum degree of 0.5 m
It was carried out under the condition of mHg. It is discharged from the die in a strand shape, cooled with water, pelletized and molded into a PE.
T / PEI / carbodiimide (weight ratio 50/50/0.
A composition of 25) was obtained.

The composition (40 parts by weight) obtained above was obtained by a conventional method and had an inherent viscosity of 0.62, antimony trioxide (Sb) was used as a catalyst, and magnesium acetate (Mg) was contained. Polyethylene terephthalate (PET) (60 parts by weight) was dried using a rotary vacuum dryer under the conditions of 180 ° C. and vacuum. The mixed pellets are put into a single-screw extruder (φ = 90 mm, L / D = 28), discharged in a strand form from a die, water-cooled and pelletized to form PET / P.
An EI / carbodiimide (weight ratio 80/20 / 0.1) polyester composition of the present invention was obtained. Table 1 shows the physical properties of the obtained polyester composition. The composition obtained is
It was a composition with little gelation and excellent melt stability.

The resulting composition was heated at 180 ° C. under vacuum for about 5 minutes.
After drying for a period of time, the mixture was put into a single-screw extruder, passed through a fiber-sintered stainless metal filter (20 μm cut) at a shear rate of 10 sec ⁻¹ , and then discharged in a sheet form from a T die. The sheet was placed on a cooling drum having a surface temperature of 25 ° C. for 7 k
2 with a draft ratio of 10 while using the electrostatic application method at a voltage of V
It was adhered and solidified at a speed of 0 m / min and rapidly cooled to obtain a substantially non-oriented unstretched film.

Subsequently, the unstretched film was stretched 3.4 times (MD stretching) at a temperature of 105 ° C. by using a longitudinal stretching machine consisting of a plurality of heated roll groups and utilizing the peripheral speed difference of the rolls. Then, after stretching 3.65 times (TD stretching) at a temperature of 100 ° C. using a stenter, heat treatment is performed at 190 ° C., and after cooling to room temperature, the film edge is removed and the film having a thickness of 10 μm is removed. An axially stretched film was obtained. Table 2 shows the characteristic values of the obtained biaxially stretched film. The obtained film was excellent in long-term heat resistance and hydrolysis resistance, and had little foreign matter.

Example 2 In the same manner as in Example 1 except that the content ratio of the polyester (A) and the polyimide (B) was changed to 90% by weight / 10% by weight among the mixing ratios of the respective components. To produce the polyester composition of the present invention. The obtained composition was a polyester composition with less gelation and excellent melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance / hydrolysis resistance and had few foreign matters.

Example 3 A polyester composition of the present invention was prepared in the same manner as in Example 1 except that the content of the terminal crosslinking agent (C) was changed to 3% by weight in the mixing ratio of each component. Manufactured. The obtained composition was a polyester composition with less gelation and excellent melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance / hydrolysis resistance and had few foreign matters.

Example 4 A polyester composition of the present invention was produced in the same manner as in Example 1 except that the same polyethylene terephthalate as in Example 1 was used except that germanium dioxide (Ge) was used as the polymerization catalyst. did. The obtained composition was a polyester composition having less gelation and particularly excellent melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance and hydrolysis resistance, and had very few foreign substances.

Example 5 The same polyethylene terephthalate as in Example 1 was used except that the polymerization catalyst was changed to antimony trioxide (Sb) and the amount of magnesium acetate (Mg) contained was changed. The polyester composition of the present invention was produced by the same method. The resulting composition has less gelation,
The polyester composition was particularly excellent in melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance / hydrolysis resistance and had few foreign matters.

Examples 6 and 7 The polyester of the present invention was prepared in the same manner as in Example 1 except that the polyimides (B-1 and B-2) shown in Reference Example 1 were used as the polyimide (B). A composition was produced. The obtained composition was a polyester composition which was less gelated and was particularly excellent in melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance / hydrolysis resistance and had few foreign matters.

Examples 8 to 11 Except that the terminal crosslinking agents (C-2, C-3, C-4, C-5) shown in Reference Examples 2 to 4 were used as the terminal crosslinking agent (C). The polyester composition of the present invention was produced in the same manner as in Example 1. The obtained composition was a polyester composition which was less gelated and was particularly excellent in melt stability.

A biaxially stretched film was formed from the obtained composition by the same method as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance / hydrolysis resistance and had few foreign matters.

Example 12 A polyester composition of the present invention was produced in the same manner as in Example 1 except that polyethylene-2,6-naphthalate (PEN) was used as the polyester (A). The obtained composition was a polyester composition which was less gelated and was particularly excellent in melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was excellent in long-term heat resistance / hydrolysis resistance and had few foreign matters.

Comparative Example 1 Polyethylene terephthalate (PET) obtained by a usual method, having an intrinsic viscosity of 0.62 and using antimony trioxide (Sb) as a catalyst and containing a large amount of magnesium acetate (Mg). A polyester composition was produced in the same manner as in Example 1 except that the pellets were used. The obtained composition was a polyester composition having too much metal content, much gelation, and poor melt stability.

A biaxially stretched film was formed from the obtained composition by the same method as in Example 1. The obtained biaxially stretched film was a film that had a large amount of foreign matter and could not be used at all in film applications where smoothness is required.

Comparative Example 2 A polyester composition was produced in the same manner as in Example 1 except that the content of the terminal crosslinking agent (C) was changed to 7% by weight in the mixing ratio of each component. . The obtained composition was a polyester composition having too little carboxyl end group, too much metal content, much gelation, and poor melt stability.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The obtained biaxially stretched film was a film that had a large amount of foreign matter and could not be used at all in film applications where smoothness is required.

Comparative Example 3 A polyester composition was produced in the same manner as in Example 1 except that the polymerization conditions of polyethylene terephthalate (PET) were changed and PET containing a large amount of carboxyl terminals was used.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The biaxially stretched film obtained was only a film having poor long-term heat resistance and hydrolysis resistance.

Comparative Example 4 A polyester composition was produced in the same manner as in Example 1 except that the polyimide (B) was not added.

Further, a biaxially stretched film was formed from the obtained composition by the same method as in Example 1. The biaxially stretched film obtained was only a film having poor long-term heat resistance and hydrolysis resistance.

Comparative Example 5 A polyester composition was produced in the same manner as in Example 1 except that the terminal crosslinking agent (C) was not added.

A biaxially stretched film was formed from the obtained composition in the same manner as in Example 1. The biaxially stretched film obtained was only a film having poor long-term heat resistance and hydrolysis resistance.

Comparative Example 6 Polyethylene terephthalate (PET) polymerization conditions and metal contents were changed to include a large amount of carboxyl terminals and a large amount of magnesium acetate (Mg).
A polyester composition was produced in the same manner as in Example 1 except that ET pellets were used. The obtained composition was a polyester composition having an excessive amount of carboxyl terminal groups and an excessive amount of metal, causing a lot of gelation, and being inferior in melt stability.

A biaxially stretched film was formed from the obtained composition by the same method as in Example 1. The biaxially stretched film obtained was only a film having poor long-term heat resistance and hydrolysis resistance. Also, there are many foreign substances,
It was a film that could not be used at all for film applications requiring smoothness.

[0105]

[Table 1]

[0106]

[Table 2]

[0107]

According to the present invention, a polyester composition comprising polyester, polyimide and a terminal cross-linking agent, which is excellent in heat resistance and has less foreign matter can be provided. Therefore, the polyester composition of the present invention can be used as a film for capacitors,
It can be preferably used in applications where both heat resistance and surface smoothness are required.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/35 C08K 5/35 C08L 79/08 C08L 79/08 Z G11B 5/73 G11B 5/73 H01G 4 / 18 327 H01G 4/18 327Z // B29K 67:00 B29K 67:00 B29L 7:00 B29L 7:00 F term (reference) 4F071 AA44 AA45 AA46 AA60 AA80 AA86 AA88 AC12A AC19A AE02A AF13 AF43 AF53 AH03 AH04 AH14 AH04 AH04 AH04 AH07 BA01 BB06 BB08 BC01 4F210 AA24 AA40 AB03 AG01 AH33 QC05 QC06 QG01 QG18 4J002 CD033 CD083 CF041 CF061 CF081 CM042 FG 5 EC0677 AB06 CB5 CB5 CG CB00 CG CB00 CG CB00 CG CB00G CB00G CG00 CG00 CG00 CG CB00G CB00G CB00G GD00 GD00 GD00 GD00 GD00 GD00 GD00 GL00 PP10

Claims (7)

[Claims] 1. A polyester (A) and a polyimide (B)
And a terminal cross-linking agent (C), the carboxyl terminal group amount is 1 to 45 equivalents / 10 ⁶ g, and the total metal content is 3
-450 ppm polyester composition. 2. An intrinsic viscosity of 0.53 to 0.85 dl / g
The polyester composition according to claim 1, wherein 3. The polyester composition according to claim 1, wherein the terminal crosslinking agent (C) is a carbodiimide compound. 4. The polyester composition according to claim 1, wherein the terminal crosslinking agent (C) is an epoxy compound or an oxazoline compound. 5. The content of the terminal crosslinking agent (C) is 0.1-5.
The polyester composition according to any one of claims 1 to 4, which is a weight%. 6. A biaxially oriented polyester film comprising the polyester composition according to claim 1. 7. A capacitor comprising the biaxially oriented polyester film according to claim 6.