JP2008100509A - Composite film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly qualified composite film which shows excellent dimensional stability at a high temperature, and is suitable particularly for a process mold releasing material and an electrical insulation material in a circuit material manufacturing process, a flooring material for a building, a molding, a magnetic recording medium, a print material and the like. <P>SOLUTION: The composite film has a metal oxide-containing layer (layer M) on at least one surface of a biaxially stretched polyester film, and shows all light transmission of 10 to 75% and a ratio of storage modulus at 60°C to storage modulus at 160°C of 1.5 to 5.0 in dynamic viscoelasticity measured at a frequency of 1 Hz in the lengthwise direction of the film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composite film comprising a metal-based oxide and a biaxially oriented polyester film, having excellent dimensional stability with suppressed thermal shrinkage and thermal expansion at high temperature, and a layer comprising a metal-based oxide. The present invention relates to a composite film that can be suitably used in various industrial material applications such as process release materials, electrical insulating materials, printing materials, molding materials, magnetic recording media, and building materials.

  Biaxially oriented polyester films are used for process release materials, electrical insulation, printing materials, molding materials, building materials, taking advantage of the features that can give strength, durability, transparency, flexibility and surface properties. And various industrial materials such as magnetic recording media.

  In recent years, the demand for flexible printed circuit boards (FPCs) has been increasing rapidly along with technological advances in electronic devices such as mobile phones, and FPCs have become thinner in response to the reduction in size and weight of such devices. Is progressing. For this reason, the thinning of the copper-clad polyimide film for FPC is also progressing at the same time, but this reduces the rigidity of the film itself, making it difficult to process the FPC.

  Therefore, in order to simplify handling at the time of processing, there may be used a method in which a slightly adhesive polyester film for reinforcement that can be peeled and removed at the end of processing is attached in advance to give rigidity. However, in the FPC manufacturing process by such a method, there are steps of heat pressing with a reinforcing polyester film attached, curing, and mounting an IC chip. In comparison, the polyester film has a large coefficient of thermal expansion and insufficient thermal dimensional stability, which may cause problems such as warping and flatness deterioration due to thermal deformation during the FPC manufacturing process. .

  In order to improve the dimensional stability against temperature and humidity, a method of providing a reinforcing layer such as metal on one or both sides of a polyester film (for example, Patent Document 1 or Patent Document 2) is disclosed. However, when the reinforcing layer is a metal, there is a problem that the strength is weaker than that of the oxide and the effect of suppressing the expansion / contraction of the polyester film is small. On the other hand, when the reinforcing layer is an oxide or other compound, it has a property of being hard but not ductile due to ionic bonds. Therefore, a crack (crack) is generated due to tension, or a crack is generated due to bending. In addition, since the oxide has a hygroscopic property, the effect of improving the dimensional stability against humidity is small, and the dimensional stability may be deteriorated by the hygroscopic expansion of the reinforcing layer itself.

On the other hand, a method for controlling the temperature dependence of the storage elastic modulus in dynamic viscoelasticity within a certain range (for example, Patent Document 3) is disclosed. However, in Patent Document 3, the storage elastic modulus of the layer provided on at least one surface of the base material is controlled, and the storage elastic modulus including the base material is not controlled.
JP 2000-11376 A JP 2002-319122 A JP 2000-131868 A

  An object of the present invention is to solve the above-mentioned problems, to provide a high-quality composite film having excellent dimensional stability at high temperatures and excellent resistance to cracking of metal-based oxides. An object of the present invention is to provide a composite film suitable for a process release material, an electrical insulating material, a building floor material, a molding material, a magnetic recording medium, and a printing member in a material manufacturing process.

In order to solve the above problems, the present invention is characterized by the following (1) to (6). That is,
(1) A biaxially oriented polyester film having a layer containing a metal oxide (M layer) on at least one side, wherein the total light transmittance of the film is in the range of 10 to 75%, and the film length In the dynamic viscoelasticity measured at a frequency of 1 Hz in the direction, a composite film having a ratio of (storage elastic modulus at a temperature of 60 ° C.) / (Storage elastic modulus at a temperature of 160 ° C.) of 1.5 to 5.0,
(2) The composite film according to (1), wherein the surface resistivity of the layer containing a metal-based oxide (M layer) is in the range of 1 × 10 ³ to 1 × 10 ¹³ Ω,
(3) The composite film according to (1) or (2), wherein the layer containing the metal-based oxide (M layer) has a thickness of 30 to 200 nm.
(4) Using a differential scanning calorimeter of a biaxially oriented polyester film, when the temperature is increased from room temperature at a rate of temperature increase of 20 ° C./min, the peak temperature of the endothermic peak of melting observed is the melting point (Tm), and the melting point The composite film according to any one of (1) to (3), wherein a minute melting peak temperature just below the melting point observed immediately before is (melting point (Tm) -55) ° C. to (Tm-15) ° C.
(5) The composite film according to any one of (1) to (4), which has a heat shrinkage rate of 0 to 1.0% at a temperature of 150 ° C. in the longitudinal direction and the width direction of the composite film,
(6) The composite film according to any one of (1) to (5), wherein the temperature expansion coefficient at a temperature of 60 to 160 ° C. in the longitudinal direction and the width direction of the composite film is 0 to 30 ppm / ° C.
It is.
(7) The metal element concentration of the M layer is 30 to 60 at. % Of the composite film according to any one of the above (1) to (6).
(8) The abundance ratio of metal atoms in the M layer that are metal bonded is 1 to 20 at. % Of the composite film according to any one of the above (1) to (7).
(9) The metal oxide of the M layer is aluminum oxide, and the abundance ratio of aluminum atoms bonded to hydroxyl groups is 0 to 50 at. % Of the composite film according to any one of the above (1) to (8).

  According to the present invention, the composite film has excellent dimensional stability and hardly generates cracks, and is used in various industrial materials such as process release materials, electrical insulating materials, printing materials, molding materials, magnetic recording media, and building materials. A composite film that can be suitably used can be obtained. In particular, when an electronic circuit material is used, it is possible to obtain a composite film in which environmental changes in temperature and humidity and dimensional changes due to storage are small, and cracking can be reduced.

  The composite film of the present invention is formed by forming a layer (M layer) containing a metal-based oxide on at least one surface of a biaxially oriented polyester film. Examples of the metal oxide include Cu, Zn, Al, Si, Fe, Ag, Ti, Mg, Sn, Zr, In, Cr, Mn, V, Ni, Mo, Ce, Ga, Hf, Nb, and Ta. , Y, W, and the like, and the oxygen atom content in the average composition when the composition analysis is performed is 10 at. The thing which is more than%. At. % Is an abbreviation of atomic%. Atomic% indicates the number of atoms per 100 atoms.

The metal element concentration of the M layer is 30 to 60 at. % Is preferred. Metal element concentration is 30 at. Less than% means that there are too many oxygen atoms relative to metal atoms, so that an incomplete structure is likely to occur (metal atoms and oxygen atoms are likely to remain unbonded), and the reinforcing effect is reduced and dimensional stability is achieved. It becomes easy to fall. 60 at. If it is more than%, there is a problem that the dimensional stability tends to be low because it has almost metal characteristics. More preferably, 30-50 at. %.
The abundance ratio of metal atoms in the M layer that are metal-bonded is 1 to 20 at. % Is preferred. The abundance ratio of metal bonds is 1 at. If it is less than%, even if the metal element concentration is as described above, there are few tough metal bonds, so cracks are likely to occur, and durability in practical properties may be insufficient. 20 at. If it is larger than%, even if the metal element concentration is as described above, the reinforcing effect is not sufficient, and the dimensional stability may not be easily lowered. Since metal atoms that are metal-bonded do not absorb moisture, it is difficult to form structural defects, and deterioration of dimensional stability can be prevented. More preferably, 2 to 20 at. %, More preferably 3 to 10 at. %. Even at the metal element concentration as described above, the surface resistivity can be controlled within the range of the present invention by controlling the abundance ratio of metal atoms that are metal-bonded. The abundance ratio of the metal bond can be controlled from the amount of evaporation of the metal and the amount of oxygen gas introduced, but it is a composition that shows a more micro structure than the metal element concentration, and the control of the oxidation reaction is important. Since the abundance ratio of metal bonds is influenced by the reaction efficiency between the metal and oxygen gas, the method of introducing oxygen gas is important. The oxygen gas introduction method is preferably supplied in the same direction as the flow direction of the metal vapor from the side of the vapor deposition source. This is because the reaction between the metal vapor and the oxygen gas is promoted and reaches the polyester film in a state where the oxidation reaction is completed, so the excess oxygen gas is taken in and the metal bond abundance ratio becomes small, or it cannot react with the oxygen gas. The metal atoms are not bonded to each other and the metal bond abundance ratio is not increased. Further, since the reaction is promoted by increasing the energy of the metal vapor or oxygen gas, it is preferable to increase the energy of the metal vapor by electron beam evaporation and increase the energy of the oxygen gas by plasma treatment or the like. The M layer is preferably on both sides of the biaxially oriented polyester film because warpage of the composite film can be reduced. In that case, the above-described metal-based oxide may contain different metal components on both surfaces, and may contain a mixture of a plurality of types of metal components, but more preferably the same on both surfaces. It is better to contain a kind of metal component. The M layer is preferably composed mainly of a metal-based oxide. For example, by using a thin film formation method such as vapor deposition or sputtering, the metal component is attached to the surface of the biaxially oriented polyester film and simultaneously oxidized. It is preferable that the film is formed by applying.

The metal-based oxide contained in the M layer preferably contains at least one of aluminum, copper, zinc, silver, and silicon elements from the viewpoints of controllability of the degree of oxidation, dimensional stability, productivity, and environmental friendliness. More preferably, an aluminum element is the main component. When the main component of the metal component of the M layer is an aluminum element, the metal-based oxide constituting the M layer is preferably aluminum oxide. Furthermore, aluminum oxide generally forms a hydrate (Al (OH) ₃ ) when it absorbs water vapor, and in the present invention, this hydrate is also included in the oxide, but aluminum bonded to a hydroxyl group. The abundance ratio of atoms is 0 to 50 at. % Is preferred. Bonding with a hydroxyl group means that the aluminum atom absorbs moisture to form a hydrate, and the abundance ratio can be measured by analyzing the bonding state of aluminum by photoelectron spectroscopy (XPS). . Due to the formation of a hydrate, a volume change occurs partially and the M layer can be distorted, causing structural defects and dimensional stability deterioration. Therefore, the abundance ratio of aluminum atoms bonded to hydroxyl groups in the aluminum oxide of the M layer is 50 at. % Or less is preferable. More preferably 40 at. % Or less. In order to reduce the abundance ratio of the aluminum atom bonded to the hydroxyl group, it is preferable not to form a hydrate, that is, not to absorb moisture. Moisture absorption can be prevented by forming aluminum atoms and oxygen atoms so tightly that the unbonded aluminum and oxygen atoms are reduced and the incomplete structure is eliminated. It is preferable that there is no incomplete structure, but if it is formed at the time of formation, it is preferable to forcibly absorb moisture all at once and to remove unbonded aluminum and oxygen atoms from the entire M layer. That is, after the M layer is formed, it is preferable to perform a forced humidification process for eliminating unbonded atoms. If the unbonded atoms remain without performing the humidification process, partial moisture absorption occurs, and it becomes easy to create a structural defect in the M layer due to a volume change due to the moisture absorption. The structural defect may cause further moisture absorption, and the abundance ratio of aluminum atoms bonded to the hydroxyl group may be higher than when no humidification treatment is performed. In addition, if the polyester film absorbs moisture when forming the M layer, moisture is released from the polyester film due to heat load during formation, and moisture is taken into the M layer, forming a hydrate. It may end up. It is preferable to reduce the water content in the polyester film before forming the M layer.

  The thickness of the M layer is preferably 30 to 200 nm. When the thickness of the M layer is smaller than 30 nm, the reinforcing effect is small, and the dimensional change due to an environmental change or load due to temperature and humidity tends to be large. The lower limit of the thickness of the M layer is preferably 50 nm, more preferably 70 nm. On the other hand, when the thickness of the M layer is larger than 200 nm, cracks are likely to occur, and peeling or dropping is likely to occur when tension is applied or bent. Further, when an M layer having a thickness larger than 200 nm is formed using a vacuum film forming apparatus, the degree of vacuum is lowered and the metal vapor is difficult to evaporate and becomes unstable. As a result, the M layer has an incomplete structure, and dimensional stability and durability tend to be insufficient. Further, in the sputtering method, if the amount of oxygen introduced is large, the surface of the target is oxidized, and the jumping out of metal atoms by sputtering becomes unstable. As a result, like the vacuum deposition method, an incomplete structure is obtained, and a composite film having poor dimensional stability and durability is likely to be obtained. The upper limit of the thickness of the M layer is preferably 180 nm, more preferably 150 nm. A preferred range is 50 to 180 nm, and a more preferred range is 70 to 150 nm.

In the composite film of the present invention, the surface resistivity of the surface on which the M layer is provided is 1.0 × 10 ³ to 1 × 10 ¹³ Ω. The surface resistivity is a characteristic value also expressed as a surface specific resistance (Ω / □), and is different from a pure surface resistance (resistance value that varies depending on the area) and line resistance (resistance such as a conducting wire). When the surface resistivity is lower than 1.0 × 10 ³ Ω, the reinforcing effect by the M layer may be insufficient. The lower limit of the surface resistivity is more preferably 1.0 × 10 ⁴ Ω, and further preferably 1.0 × 10 ⁵ Ω. On the other hand, when the surface resistivity is higher than 1 × 10 ¹³ Ω, since the oxidation has progressed excessively, there is a tendency for generation of cracks and reduction in dimensional stability. That is, by controlling the surface resistivity within the above range, the structure of the M layer is stabilized, a barrier effect against water vapor and moisture is exhibited, and the reinforcing effect is easily increased. The upper limit of the surface resistivity is more preferably 1 × 10 ¹² Ω, and further preferably 1 × 10 ¹⁰ Ω. A more preferable range is 1.0 × 10 ⁴ to 1 × 10 ¹² Ω, and a further preferable range is 1.0 × 10 ⁵ to 1 × 10 ¹⁰ Ω.

  Since the surface resistivity varies depending on the range of the surface resistivity, the measurable device is different. First, the support is measured by the method i), and the sample whose surface resistivity cannot be measured is measured by the method ii). . The average value of five measurement results is defined as the surface resistivity in the present invention. That is, i) The low resistivity measurement is first performed by a method based on JIS-K7194 (1994). Let the average value measured 5 times be surface resistivity. However, when the surface resistivity is relatively high, measurement may not be possible with the method i). In that case, ii) high resistivity measurement is measured according to JIS-C2151 (1990). Similarly, measurement is made 5 times and the average value is defined as the surface resistivity.

  In the dynamic viscoelasticity measured at a frequency of 1 Hz in the longitudinal direction of the composite film of the present invention, the ratio of (storage elastic modulus at a temperature of 60 ° C.) / (Storage elastic modulus at a temperature of 160 ° C.) is 1.5 to 5.0. is there. By controlling the storage elastic modulus within the range of the present application, it is possible to obtain a composite film excellent in dimensional stability at high temperatures while suppressing a decrease in storage elastic modulus at high temperatures. By controlling the thickness and surface resistivity of the layer containing the metal-based oxide, it can be controlled within the scope of the present invention. A preferable value as an upper limit of the ratio of (storage modulus at a temperature of 60 ° C.) / (Storage modulus at a temperature of 160 ° C.) is 4.0, and a more preferable value is 3.0, and storage at a temperature of 60 ° C. A preferred value as the lower limit of the ratio of (elastic modulus) / (storage elastic modulus at a temperature of 160 ° C.) is 2.0. A preferred range is 1.5 to 4.0, and a more preferred range is 2.0 to 3.0. When the ratio of (storage elastic modulus at a temperature of 60 ° C.) / (Storage elastic modulus at a temperature of 160 ° C.) is less than 1.5, the storage elastic modulus of the composite film has substantially no temperature dependence. In many cases, the reinforcing effect of the metal oxide film on the axially oriented polyester film is too high, and problems such as cracks and peeling easily occur. Moreover, when the ratio of (storage modulus at a temperature of 60 ° C.) / (Storage modulus at a temperature of 160 ° C.) exceeds 5.0, the storage modulus at a high temperature is greatly reduced, and the dimensional stability of the composite film in the range is high. May deteriorate rapidly.

    In order to obtain (storage elastic modulus at a temperature of 60 ° C.) / (Storage elastic modulus at a temperature of 160 ° C.), a dynamic viscoelasticity evaluation apparatus DMS6100 (manufactured by Seiko Instruments Inc.) was used, and the longitudinal direction of the film was taken as the sample length. A sample having a sample width of 10 mm and a sample length (distance between chucks) of 20 mm is measured under the following conditions.

Measurement temperature range: 30-200 ° C
Vibration frequency: 1Hz
Vibration displacement (distortion): 10 (mm)
Temperature increase rate: 2 (° C / min)
Based on the data measured under the above conditions, a graph is drawn with the obtained storage modulus as the vertical axis and the temperature (30 to 200 ° C.) as the horizontal axis, and the value of the storage modulus at a temperature of 60 ° C. And the ratio of the storage elastic modulus at a temperature of 160 ° C.

  When the temperature of the biaxially oriented polyester film used in the composite film of the present invention is increased from room temperature at a rate of temperature increase of 20 ° C./min using a differential scanning calorimeter, the peak temperature of the endothermic peak of melting observed is the melting point ( As Tm), it is preferable that the minute melting peak temperature just below the melting point observed immediately before the melting point is (melting point (Tm) −55) ° C. to (Tm−15) ° C. When the minute melting peak temperature just below the melting point is in the above range, a base film for reducing thermal shrinkage and thermal expansion at a high temperature that meets the object of the present invention can be obtained as a biaxially oriented polyester film. The minute melting peak is involved in the heat treatment temperature of the biaxially oriented polyester film, and the lower limit is preferably (Tm-50) ° C, more preferably (Tm-45) ° C, and the upper limit is preferably ( Tm-20) ° C, more preferably (Tm-25) ° C. A more preferable range is (Tm-50) to (Tm-20) ° C, and a more preferable range is (Tm-45) to (Tm-25) ° C.

  The composite film of the present invention preferably has a temperature expansion coefficient in the range of 0 to 30 ppm / ° C. at temperatures of 60 ° C. to 160 ° C. in the longitudinal direction and the width direction. The temperature expansion coefficient within the above range is preferable from the viewpoint of dimensional stability in circuit material processing. The upper limit of the temperature expansion coefficient is preferably 25 ppm / ° C., more preferably 20 ppm / ° C., and the lower limit is preferably 5 ppm / ° C., more preferably 10 ppm / ° C. A more preferable range is 5 to 25 ppm / ° C, and a further preferable range is 10 to 20 ppm / ° C. Moreover, it is preferable that the difference between the thermal expansion coefficients in the longitudinal direction and the width direction is 5 ppm / ° C. or less from the viewpoint of avoiding twist curl during high-temperature processing.

  The composite film of the present invention preferably has a thermal shrinkage rate of 0 to 1.0% at a temperature of 150 ° C. in the longitudinal direction and the width direction. It is preferable that the thermal shrinkage rate is within the above range from the viewpoint of dimensional stability in circuit material processing. The upper limit value of the heat shrinkage rate is preferably 0.5%, more preferably 0.3%. A more preferable range is 0 to 0.5%, and a further preferable range is 0 to 0.3%. Moreover, it is preferable that the difference between the thermal shrinkage rates in the longitudinal direction and the width direction is 0.5% or less from the viewpoint of avoiding twist curl during high-temperature processing.

  In the present invention, the longitudinal direction of the composite film is a direction generally referred to as the MD direction, and refers to the same direction as the longitudinal direction during the polyester film manufacturing process, and the width direction of the composite film is generally It is a direction called TD direction, and refers to the same direction as the width direction during the polyester film manufacturing process.

The composite film of the present invention has a total light transmittance of 10 to 75%. If it is higher than 75%, the oxidation has progressed too much, so the M layer becomes hard and brittle, and cracks are likely to occur due to tension and curvature, and the hygroscopic expansion of the oxide tends to occur and the dimensional stability tends to be poor.
The lower limit of the total light transmittance is more preferably 15%, still more preferably 20%. On the other hand, the upper limit is more preferably 70%, and still more preferably 60%. A more preferable range is 15 to 70%, and a more preferable range is 20 to 60%.

The total light transmittance is measured on the support using the following measuring device based on JIS-K7105 (1981). The average value of five measurement results was defined as the total light transmittance in the present invention. Measure five times to obtain the average value.
・ Measurement device: Direct reading haze meter HGM-2DP (for C light source) Suga Test Instruments Co., Ltd. ・ Light source: Halogen lamp 12V, 50W
-Light receiving characteristics: 395 to 745 nm
Measurement environment: temperature 23 ° C., humidity 65% RH.

  In the present invention, the polyester film is composed of, for example, a polymer having an acid component such as aromatic dicarboxylic acid, alicyclic dicarboxylic acid or aliphatic dicarboxylic acid or a diol component as a structural unit (polymerization unit). It is.

  Examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-diphenyldicarboxylic acid. Acid, 4,4′-diphenyl ether dicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, and the like can be used. Among them, terephthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid can be preferably used. . As the alicyclic dicarboxylic acid component, for example, cyclohexane dicarboxylic acid or the like can be used. As the aliphatic dicarboxylic acid component, for example, adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like can be used. These acid components may be used alone or in combination of two or more.

  Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2'-bis (4'- β-hydroxyethoxyphenyl) propane and the like can be used, and among them, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, diethylene glycol and the like can be preferably used, and ethylene glycol is particularly preferable. etc It can be used. These diol components may be used alone or in combination of two or more.

  The polyester used in the polyester film of the present invention may be copolymerized with a monofunctional compound such as lauryl alcohol or phenyl isocyanate, trimellitic acid, pyromellitic acid, glycerol, pentaerythritol, 2,4-dioxy. A trifunctional compound such as benzoic acid may be copolymerized within a range in which the polymer is substantially linear without excessive branching or crosslinking. In addition to the acid component and diol component, the present invention includes aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid, m-hydroxybenzoic acid, and 2,6-hydroxynaphthoic acid, p-aminophenol, and p-aminobenzoic acid. As long as the effect is not impaired, the copolymerization can be further carried out.

  As polyester used for the polyester film of the present invention, polyethylene terephthalate and polyethylene naphthalate are preferable. Further, these copolymers and modified products may be used, and polymer alloys with other thermoplastic resins may be used. The polymer alloy here is a polymer multi-component system, and may be a block copolymer by copolymerization or a polymer blend by mixing.

  In particular, the polyester film of the present invention is preferable because the polymer alloy of the polyester resin and the polyimide resin can control the heat resistance (glass transition temperature) depending on the mixing ratio, so that the polymer design can be adapted to the use conditions. The mixing ratio of the polymer can be examined using NMR method (nuclear magnetic resonance method) or microscopic FT-IR method (Fourier transform microinfrared spectroscopy).

  As a polyimide-type resin, what contains a structural unit as shown by the following general formula, for example is preferable.

However, R ¹ in the formula is

Represents one or two or more groups selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. R ² in the formula is

Represents one or two or more groups selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.

  From the viewpoints of melt moldability and affinity with polyester, a polyetherimide containing an ether bond in the polyimide component as shown by the following general formula is particularly preferred.

(Wherein R ³ is a divalent aromatic or aliphatic residue having 6 to 30 carbon atoms, R ⁴ is a divalent aromatic residue having 6 to 30 carbon atoms, From the group consisting of alkylene groups having 2 to 20 carbon atoms, cycloalkylene groups having 2 to 20 carbon atoms, and polydiorganosiloxane groups chain-terminated with alkylene groups having 2 to 8 carbon atoms Selected divalent organic group.)
As said R < ³ >, R < ⁴ >, the aromatic residue shown by the following formula group can be mentioned, for example.

  In the present invention, 2,2-bis [4- (2,3-dicarboxyphenoxy) phenyl] propane dianhydride and m-phenylenediamine from the viewpoint of affinity with polyester, cost, melt moldability, and the like, or A polymer having a repeating unit represented by the following formula, which is a condensate with p-phenylenediamine, is preferable.

Or

(N is an integer of 2 or more, preferably an integer of 20 to 50)
This polyetherimide is available from GE Plastics under the trade name “Ultem” (registered trademark).

  In the present invention, for example, as a method of mixing a polyester resin and a polyimide resin, a method of pre-melting and kneading (pelletizing) a mixture of a polyester resin and a polyimide resin before melt extrusion to form a master chip, or at the time of melt extrusion There is a method of mixing and melt-kneading. Of these, a method of pre-kneading into a master chip using a high-shear mixer with high shear stress such as a twin screw extruder is preferably exemplified. In that case, the mixed master chip raw material may be put into an ordinary single-screw extruder to form a melt film, or may be directly sheeted without forming a master chip in a state where high shear is applied. When mixing with a twin screw extruder, from the viewpoint of reducing poor dispersion, a screw equipped with a triple twin screw type or a double twin screw type is preferable. Moreover, when mixing a polyester resin and a polyimide resin, since there is a difference in melt viscosity, it is preferable to prepare a master chip in which a polyimide resin is mixed at a high concentration. In particular, the mixing weight ratio of polyester resin / polyimide resin is 10 / 90 to 70/30 is preferable, and a more preferable range is 30/70 to 60/40.

  Setting the temperature range of the kneading part to a preferable range makes it easy to increase the shearing stress and to reduce defective dispersion. The residence time at that time is preferably in the range of 1 to 5 minutes. Moreover, it is preferable that screw rotation speed shall be 100-500 rotation / min, More preferably, it is the range of 200-400 rotation / min. Even when the screw rotation speed is set within a preferable range, high shear stress is easily applied, and defective dispersion is easily reduced. Further, the ratio of (screw shaft length / screw shaft diameter) of the twin screw extruder is preferably in the range of 20 to 60, more preferably in the range of 30 to 50.

  Further, in the twin screw, it is preferable to provide a kneading part by a kneading paddle or the like in order to increase the kneading force, and the kneading part is preferably formed in a screw shape having two or more, more preferably three or more. At this time, the mixing order of the raw materials is not particularly limited, and a method in which all raw materials are blended and then melt-kneaded by the above method, a part of the raw materials are blended and then melt-kneaded by the above method, and the remaining raw materials are blended. Any method such as a method of melt kneading or a method of mixing a part of raw materials and mixing the remaining raw materials using a side feeder during melt kneading by a single-screw or biaxial extruder may be used. Further, a method using a supercritical fluid described in Journal of Plastics Processing Society of Japan, “Molding”, Vol. 15, No. 6, pp. 382 to 385 (2003) can be preferably exemplified.

  In the present invention, the polyester film may have a laminated structure of two or more layers. If it is a laminated structure, for example, the surface roughness of both surfaces can be controlled, and smoothness is given to one surface giving priority to the reduction of surface defects, or film formation / processing is performed on the other surface. Roughness giving priority to imparting conveyance, running performance and running durability in the process can be given.

  The polyester film is provided with inorganic and organic particles such as clay, mica, titanium oxide, calcium carbonate, carion, talc, wet silica, and the like in order to impart slipperiness, abrasion resistance, scratch resistance and the like to the surface. Inorganic particles such as dry silica, colloidal silica, calcium phosphate, barium sulfate, alumina, zirconia, organic particles containing acrylic acid, styrene resin, thermosetting resin, silicone, imide compound, etc., added during polyester polymerization reaction Particles (so-called internal particles) that are precipitated by the catalyst or the like may be added. The particle size of the particles can be examined by TEM or the like, and the addition amount of the particles can be examined by an X-ray microanalyzer or pyrolysis gas chromatography mass spectrometry.

  In this invention, the thickness as a support body can be suitably determined according to a use in the range of 2-500 micrometers. In particular, 25 to 250 μm is preferable for circuit materials and electrical insulating materials, and 3 to 6 μm is preferable for magnetic recording media.

  Moreover, it is preferable that the thickness of the polyester film which comprises the composite film of this invention is 2-500 micrometers. In particular, 25 to 250 μm is preferable for circuit materials and electrical insulating materials, and 3 to 6 μm is preferable for magnetic recording media.

  The composite film of the present invention as described above is manufactured, for example, as follows.

  First, a biaxially oriented polyester film constituting the base film is manufactured. In order to produce a polyester film, for example, polyester pellets are melted using an extruder, discharged from a die, and then cooled and solidified to form a sheet. At this time, it is preferable to filter the polymer with a fiber-sintered stainless metal filter in order to remove unmelted material in the polymer. In addition, in order to impart easy slipping, abrasion resistance, scratch resistance, etc. to the surface of the polyester film, inorganic particles and organic particles such as clay, mica, titanium oxide, calcium carbonate, carion, talc, wet silica, dry type Inorganic particles such as silica, colloidal silica, calcium phosphate, barium sulfate, alumina, zirconia, organic particles containing acrylic acid, styrene resin, thermosetting resin, silicone, imide compound, etc., added during polyester polymerization reaction It is also preferable to add particles precipitated by a catalyst or the like (so-called internal particles). Furthermore, various additives such as compatibilizers, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, and the like, provided that they do not inhibit the present invention. Conductive agents, crystal nucleating agents, ultraviolet absorbers, flame retardants, flame retardant aids, pigments, dyes, and the like may be added.

  Then, after extending | stretching the said sheet | seat to the biaxial of a longitudinal direction and the width direction, it heat-processes. As the stretching method, a sequential biaxial stretching method such as stretching in the width direction after stretching in the longitudinal direction, a simultaneous biaxial stretching method in which the longitudinal direction and the width direction are simultaneously stretched using a simultaneous biaxial tenter, etc. Further, a method of combining a sequential biaxial stretching method and a simultaneous biaxial stretching method is included.

  The heat treatment after the stretching process may be carried out in one stage, but in order to control the storage elastic modulus within the range of the present invention as a final composite film so that it becomes a composite film excellent in dimensional stability, It is preferable to carry out in multiple stages. The other stage is to carry out in two or more stages by changing the heat treatment temperature. Of these, a two-stage heat treatment is preferred.

The heat treatment temperature can be determined based on the melting point of the polyester. The heat treatment temperature is preferably 150 ° C. to [melting point of polyester (Tm) −15] ° C., and the heat treatment time is preferably 0.5 to 10 seconds. In particular, the heat treatment temperature in the first stage is preferably (Tm-55) to (Tm-15) ° C., more preferably (Tm-50) to (Tm-20) ° C., and particularly preferably (Tm-45) to (T Tm−25) ° C., the second stage heat treatment temperature is set lower than the first stage. Further, it is more preferable that only the second heat treatment step is relaxed at a relaxation rate of 1 to 5% in the width direction. According to the above-described multi-stage heat treatment process, molecular chain relaxation that is effective in reducing heat treatment proceeds while improving dimensional stability related to thermal expansion, so both thermal expansion and heat shrinkage, which are the effects of the present invention, are achieved. It becomes easy to raise a dimensional change And the polyester film manufactured in this way is wound up by a roll.

  Next, the layer (M layer) containing a metal-type oxide is provided on both surfaces of the polyester film heat-treated as described above. At this time, in order to set the value of the surface resistivity and the temperature expansion coefficient as the support as described above, preferably the value of the total light transmittance as the support as described above, Control the oxidation state of the oxide.

  As a method for forming the M layer, physical vapor deposition or chemical vapor deposition can be used. The physical vapor deposition method on the polyester film includes a vacuum vapor deposition method and a sputtering method. Particularly, the vacuum vapor deposition method is preferable from the viewpoint of easy control of the degree of oxidation, and an electron beam vapor deposition method capable of increasing the energy of the metal vapor is preferable.

  In order to control the degree of oxidation of the metal oxide composing the M layer, it is basically necessary to control the amount of metal evaporation and the amount of oxygen gas introduced. If the amount of metal evaporation is constant, the degree of oxidation decreases if the amount of introduced oxygen gas is reduced, and the degree of oxidation increases if the amount of introduced oxygen gas is increased. On the contrary, if the amount of introduced oxygen gas is constant, the degree of oxidation increases if the amount of metal evaporation is reduced, and the degree of oxidation decreases if the amount of metal evaporation is increased. At this time, the oxygen gas is preferably supplied in the same direction as the flow direction of the metal vapor from the side of the vapor deposition source.

  Since the surface resistivity of the composite film increases as the oxidation degree of the M layer increases, it is controlled by adjusting the amount of oxygen gas introduced during deposition, the position of the oxygen gas supply nozzle, the amount of evaporation of metal components, and the film transport speed. can do. In particular, the effects of metal evaporation and film transport speed are large.

For example, if the amount of metal evaporation is constant, the surface resistivity decreases when the oxygen gas introduction amount is decreased, and the surface resistivity increases when the oxygen gas introduction amount is increased. Conversely, if the amount of oxygen gas introduced is constant, reducing the amount of metal evaporation or reducing the film transport speed increases the surface resistivity because the oxidation reaction is likely to proceed, while increasing the amount of metal evaporation, When the film conveyance speed is increased, the oxidation reaction is less likely to proceed completely with respect to the supplied metal, so that the surface resistivity is decreased.
Further, the degree of oxidation in the present application is different from the oxygen concentration obtained by the composition analysis of the layer containing the metal oxide (M layer). The oxygen concentration in the composition analysis represents the ratio of oxygen element, but the oxidation degree of the present invention represents the bonding state of the metal element, and the high degree of oxidation means that the ratio of the metal element bonding to the oxygen element is high. Means that. Although the surface resistivity has a correlation with the metal element concentration in the M layer, it tends to change depending on the bonding state of the metal atoms even if the metal element concentration is the same, and the abundance ratio of the metal-metal bond is particularly affected. It is easy to control the surface resistivity within the range of 1 × 10 ³ to 1 × 10 ¹³ Ω by controlling the abundance ratio of the metal-metal bond without excessively increasing the oxygen concentration.

  And the temperature expansion coefficient of a composite film is controllable by the orientation state of the film reflected in the Young's modulus etc. of the polyester film before vapor deposition, the metal evaporation amount at the time of vapor deposition, and oxygen gas introduction amount. Further, the temperature expansion coefficient of the composite film can be controlled within the range of the present invention by controlling the metal component and thickness of the M layer.

  For example, when the M layer is made of a hard metal oxide such as aluminum oxide, the temperature expansion coefficient is likely to decrease, and when the thickness of the M layer is increased, the temperature expansion coefficient is likely to be decreased.

  Since the total light transmittance increases as the degree of oxidation increases, the oxygen gas introduction amount during deposition, the position of the oxygen gas supply nozzle, the evaporation amount of metal components, and the film transport speed must be adjusted, as with the surface resistivity. Can be controlled. Specifically, to increase the total light transmittance by increasing the degree of oxidation, increase the amount of oxygen gas introduced and increase the amount of oxygen gas that can be reacted, or install the oxygen gas supply nozzle at a position where it can easily react. Control is performed by facilitating the advancement, reducing the evaporation amount of the metal component, increasing the oxygen concentration, and slowing the film transport speed to increase the reaction time. In particular, the influence of the amount of oxygen gas introduced is large.

  In the present invention, a polyester film or a support obtained using the polyester film, if necessary, heat treatment, microwave heating, molding, surface treatment, lamination, coating, printing, embossing, etching, Arbitrary processing such as may be performed.

  Hereinafter, the method for producing the support of the present invention will be described as an example in which polyethylene terephthalate (PET) is used as polyester. Of course, the present application is not limited to a support using a PET film, but may be one using another polymer. For example, when a polyester film is formed using polyethylene-2,6-naphthalenedicarboxylate having a high glass transition temperature or a high melting point, it may be extruded or stretched at a temperature higher than the following temperature.

  First, polyethylene terephthalate is prepared. Polyethylene terephthalate is manufactured by one of the following processes. (1) Using terephthalic acid and ethylene glycol as raw materials, a low molecular weight polyethylene terephthalate or oligomer is obtained by direct esterification reaction, and then a polymer is obtained by polycondensation reaction using antimony trioxide or titanium compound as a catalyst. Process (2) A process in which dimethyl terephthalate and ethylene glycol are used as raw materials, a low molecular weight product is obtained by transesterification, and then a polymer is obtained by polycondensation reaction using antimony trioxide or a titanium compound as a catalyst. Here, the reaction proceeds even without a catalyst, but the transesterification usually proceeds using a compound such as manganese, calcium, magnesium, zinc, lithium, titanium as a catalyst, and the transesterification reaction is carried out. After the completion of the reaction, a phosphorus compound may be added for the purpose of inactivating the catalyst used in the reaction.

  When the polyester constituting the film contains inert particles, it is preferable to disperse the inert particles in a predetermined proportion in the form of a slurry in ethylene glycol and add this ethylene glycol during polymerization. When adding inert particles, for example, water sol or alcohol sol particles obtained at the time of synthesis of the inert particles are added without drying once, the dispersibility of the particles is good. It is also effective to mix an aqueous slurry of inert particles directly with PET pellets and knead them into PET using a vented biaxial kneading extruder. As a method for adjusting the content of the inert particles, a master pellet of a high concentration of inert particles is prepared by the above method, and this is diluted with PET that does not substantially contain inert particles during film formation. A method for adjusting the content of the active particles is effective.

  Next, the obtained PET pellets are dried under reduced pressure at 180 ° C. for 3 hours or more, and then supplied to an extruder heated to 270 to 320 ° C. under a nitrogen stream or under reduced pressure so that the intrinsic viscosity does not decrease. The film is extruded from a slit-shaped die and cooled on a casting roll to obtain an unstretched film. At this time, it is preferable to use various types of filters, for example, filters made of materials such as sintered metal, porous ceramics, sand, and wire mesh, in order to remove foreign substances and altered polymers. Moreover, you may provide a gear pump as needed in order to improve fixed_quantity | feed_rate supply property. When laminating films, a plurality of different polymers are melt laminated using two or more extruders and manifolds or merging blocks.

  Next, this unstretched film is biaxially stretched sequentially in the longitudinal and width directions. An unstretched polyester film is heated with a heated roll group, and stretched in a multi-stage of one or two or more stages in the longitudinal direction 2 to 5 times, preferably 2.5 to 4.5 times, more preferably 3 to 4 times. (MD stretching). The stretching temperature ranges from Tg (glass transition temperature of polyester) to (Tg + 60) ° C., preferably (Tg + 5) to (Tg + 55) ° C., and more preferably (Tg + 10) to (Tg + 50) ° C. Thereafter, it is cooled by a cooling roll group of 20 to 50 ° C.

  As a stretching method in the width direction following MD stretching, for example, a method using a tenter is common. The both ends of this film are gripped with clips, guided to a tenter, and stretched in the width direction (TD stretching). The stretching temperature is preferably Tg to (Tg + 80) ° C., more preferably (Tg + 10) to (Tg + 70) ° C., and further preferably (Tg + 20) to (Tg + 60) ° C. The draw ratio is preferably 2.0 to 6.0 times, more preferably 3.0 to 5.0 times, and still more preferably 3.0 to 4.5 times.

  And when the manufacturing process of a polyester film includes multistage stretching, that is, a re-stretching process, the first stage stretching temperature is as described above, but the second stage stretching temperature is preferably Tg + 40 ° C. to Tg + 120 ° C., more preferably. Is Tg + 60 ° C. to Tg + 100 ° C. When the stretching temperature is out of the above range, the film may be broken frequently due to insufficient heat amount or excessive crystallization, resulting in a decrease in productivity or a sufficient decrease in orientation, resulting in a decrease in strength. is there.

  Further, if necessary, re-longitudinal stretching and / or re-lateral stretching is performed. In that case, the film is heated with a group of heating rolls and stretched again in the longitudinal direction by 1.1 to 2.5 times, preferably 1.2 to 2.4 times, more preferably 1.3 to 2.3 times. And it cools with a 20-50 degreeC cooling roll group. The stretching temperature is preferably in the range of Tg to (Tg + 100) ° C, more preferably in the range of (Tg + 20) to (Tg + 80) ° C, and still more preferably in the range of (Tg + 40) to (Tg + 60) ° C. Next, stretching in the width direction is performed again using a stenter. The stretching temperature is preferably in the range of Tg to 250 ° C, more preferably in the range of (Tg + 20) to 240 ° C, and still more preferably in the range of (Tg + 40) to 220 ° C. The draw ratio is preferably 1.1 to 2.5 times, more preferably 1.15 to 2.2 times, and still more preferably 1.2 to 2.0 times.

  Subsequently, this stretched film is heat-treated under tension or while relaxing in the width direction. As for the heat treatment conditions, the heat treatment temperature is preferably 150 ° C. to 240 ° C., and the heat treatment time is preferably in the range of 0.5 to 10 seconds. It is preferable to carry out the heat treatment process in two or more stages. In particular, the heat treatment temperature of the first stage is preferably set to 200 to 240 ° C, more preferably 205 to 235 ° C, and particularly preferably 210 to 230 ° C. The heat treatment temperature of the second stage is set lower than that of the first stage, and is preferably set to 150 to 200 ° C, more preferably 160 to 190 ° C. Further, it is more preferable that only the second heat treatment step is relaxed at a relaxation rate of 1 to 5% in the width direction. According to the above-described multi-stage heat treatment process, the molecular chain relaxation for reducing the thermal shrinkage effectively proceeds while enhancing the dimensional stability related to thermal expansion, so that the dimensional stability that is the effect of the present invention can be easily improved. Thereafter, the film edge is removed and wound on a roll.

  Next, a method for providing a layer (M layer) containing a metal-based oxide on both sides of the PET film obtained as described above will be described.

  In order to form the M layer on the PET film surface, for example, a vacuum vapor deposition apparatus as shown in FIG. 1 is used. In this vacuum vapor deposition apparatus 11, the polyester film travels inside the vacuum chamber 12 from the unwinding roll unit 13 through the cooling drum 16 to the winding roll unit 18. At that time, the metal material 19 in the crucible 23 is heated and evaporated by the electron beam 21 irradiated from the electron gun 20, and oxygen gas is introduced from the oxygen supply nozzle 24, and the evaporated metal is oxidized and the cooling drum 16. Vapor deposition on the upper polyester film. Since the present invention requires M layers on both sides, after depositing a metal-based oxide on one surface (first side), the single-side vapor-deposited polyester film is removed from the take-up roll section 18 and set on the unwind roll section 13. Similarly, a metal-based oxide is deposited on the opposite surface (second surface). In this vacuum vapor deposition apparatus 11, the oxygen supply nozzle 24 is installed directly beside the crucible 23 as a vapor deposition source so that the degree of oxidation can be easily controlled, and the metal vapor and the oxygen gas flow in the same direction. I have to. As a result, the reaction space between the metal vapor and oxygen gas is also increased.

Here, the inside of the vacuum chamber 12 is preferably decompressed to 1.0 × 10 ^{−8 to} 1.0 × 10 ² Pa. Further, in order to form a dense M layer with few deteriorated portions, it is preferable to reduce the pressure to 1.0 × 10 ^{−6 to} 1.0 × 10 ⁻¹ Pa.

  The cooling drum 16 preferably has a surface temperature in the range of −40 to 60 ° C. More preferably, it is -30-30 degreeC, More preferably, it is -30-30 degreeC.

  The electron beam 21 is preferably performed with an output of 2.0 to 8.0 kW. More preferably, it is 3.0-7.0 kW, More preferably, it exists in the range of 4.0-6.0 kW. Note that the metal material 19 may be heated and evaporated by directly heating the crucible.

  Oxygen gas is introduced into the vacuum chamber 12 at a flow rate of 0.5 to 10 L / min using the gas flow rate control device 26. More preferably, it is 1.5-8 L / min, More preferably, it is 2.0-5 L / min.

  As for the conveyance speed of the polyester film in the inside of the vacuum chamber 12, 20-200 m / min is preferable. More preferably, it is 30-100 m / min, More preferably, it is 40-80 m / min. When the conveyance speed is slower than 20 m / min, it is necessary to considerably reduce the evaporation amount of the metal in order to control the M layer thickness as described above. Therefore, since it is necessary to reduce the amount of oxygen gas introduced, it becomes very difficult to control the degree of oxidation. When the conveyance speed is higher than 200 m / min, the contact time with the cooling drum is shortened, so that tears and wrinkles are generated due to heat, and productivity tends to be reduced. In addition, the metal vapor and the oxygen gas are likely to be formed in an insufficient reaction state, and the degree of oxidation may be difficult to control.

  The conveying tension of the polyester film inside the vacuum chamber 12 is preferably 50 to 150 N / m. More preferably, it is 70-120 N / m, More preferably, it is 80-100 N / m. However, it is preferable that the conveyance tension is weaker than that of the first surface during the evaporation of the second surface. The transport tension on the second surface is preferably 5 to 30 N / m lower than the transport tension on the first surface, more preferably 7 to 25 N / m, and still more preferably 10 to 20 N / m. This is because the polyester film loses the force to shrink due to the heat load during the evaporation of the first side, and when it is run with the same transport tension as the first side during the evaporation of the second side, tearing and wrinkles due to heat occur, This is because productivity tends to be impaired. Furthermore, when the surface roughness of the polyester film varies depending on the surface, it is preferable to deposit the rough surface first. This is to improve the adhesion to the cooling drum during the second-side vapor deposition. Vapor deposition may be performed one side at a time, or both sides may be performed in one step.

  In addition, it is preferable to supply the oxygen gas from the side of the deposition source in the same direction as the flow direction of the metal vapor in order to control the surface resistivity by controlling the metal-metal bonding state of the M layer of the present application. By supplying in the same direction as the flow direction of the metal vapor, the disturbance of the metal vapor due to the oxygen gas is reduced, and the desired thickness and degree of oxidation can be easily controlled. In addition, since the reaction space between oxygen gas and metal vapor becomes large, the oxidation reaction is completed before reaching the polyester film, and it becomes possible to form a stable deposited film without structural defects, improving dimensional stability. To do. In the oxygen supply nozzle close to the cooling drum, since the gas flow hits the metal vapor perpendicularly, it is difficult to control the desired thickness, and it is particularly difficult to increase the film thickness. Furthermore, since the reaction space becomes small, metal atoms arrive at the polyester film by an incomplete oxidation reaction, resulting in an incomplete structure, which deteriorates dimensional stability. In addition, since there are oxygen supply nozzles at the beginning and the end of deposition on the polyester film, a layer structure in which the oxygen concentration is high at the interface with the polyester film and the surface of the M layer tends to be obtained. If there is a layer having a different composition in the M layer, the structure tends to be disturbed and the dimensional stability tends to be lowered. In order to stabilize the M layer and improve the denseness after the deposition, it is preferable to return the inside of the vacuum deposition apparatus to normal pressure and to rewind the wound film. In particular, it is preferable to perform humidification rewinding because the chance of contact between the water vapor and the M layer is increased. Aging is preferably performed at a temperature of 20 to 50 ° C. for 1 to 3 days, and more preferably, aging is performed in an environment with a humidity of 60% or more and no condensation. Moreover, it is preferable to store the produced polyester film in a low humidity environment so as not to absorb moisture, and packaging that prevents moisture absorption as much as possible during transportation is preferable. This is because moisture absorption of the polyester film adversely affects the formation of the M layer.

(Methods for measuring physical properties and methods for evaluating effects)
The characteristic value measurement method and effect evaluation method in the present invention are as follows.

(1) Storage modulus DMS6100 (manufactured by Seiko Instruments Inc.) was used, and a sample having a sample width of 10 mm and a sample length (distance between chucks) of 20 mm was measured under the following conditions, with the film longitudinal direction being the sample length.

Measurement temperature range: 30-200 ° C
Vibration frequency: 1Hz
Vibration displacement (distortion): 10 (mm)
Temperature increase rate: 2 (° C / min)
Based on the data measured under the above conditions, the storage elastic modulus obtained was plotted on the horizontal axis of temperature (30 to 200 ° C.). The value of storage elastic modulus at 60 ° C. and the temperature The ratio was determined from the value of the storage elastic modulus at 160 ° C.

(2) Temperature expansion coefficient A thermomechanical measuring device TMA / SS6100 (manufactured by Seiko Instruments Inc.) was used, and a load of 3 g was applied to a sample having a sample width of 4 mm and a sample length (distance between chucks) of 20 mm. The temperature was raised from room temperature to 175 ° C. (setting 185 ° C.) at a rate of temperature rise of 10 ° C./min and held for 10 minutes. Thereafter, the temperature was lowered to 40 ° C. at 10 ° C./min and held for 20 minutes. From the dimensional change amount from 160 ° C. to 60 ° C. at this time, the thermal expansion coefficient was determined by the following formula.

Thermal expansion coefficient α (1 / ° C.) = {(L160−L60) / L0} / ΔT
L0: film length at 23 ° C. L160: film length at 160 ° C. during temperature drop L60: film length at 60 ° C. during temperature drop ΔT: temperature change (160−60 = 100).

(3) Thermal contraction rate It measured on condition of the following according to JIS C-2318. The number of samples was measured for each sample, and the average value was taken.

Sample size: width 10 mm, marked line interval 200 mm
Measurement conditions: Temperature 150 ° C., treatment time 30 minutes, no load state 150 ° C. The heat shrinkage rate was obtained from the following equation.

Thermal contraction rate (%) = [(L0−L) / L0] × 100
L0: Mark interval before heat treatment L: Mark interval after heat treatment.

(4) Thickness of M layer Cross-sectional observation is performed on the following conditions, the average value of the thickness of 9 points obtained in total (nm) is computed, and it is set as the thickness (nm) of M layer.
・ Measuring device: Transmission electron microscope (TEM) Hitachi H-7100FA type ・ Measuring conditions: Acceleration voltage 100 kV
-Measurement magnification: 200,000 times-Sample preparation: Ultra-thin film section method-Observation surface: TD-ZD cross-section-Number of measurements: 3 points per field and 3 fields are measured.

(5) Composition analysis A composition analysis in the depth direction is performed under the following conditions. The carbon concentration is 50 at. The depth exceeding% is defined as the interface between the M layer and the polyester film, the surface layer to the interface are divided equally into 5 parts, and the composition analysis is performed with the center point of each section as the measurement point. An average value is calculated from the composition of each measurement point obtained, and is defined as the average composition in the present invention.
・ Measurement device: X-ray photoelectron spectrometer Quantera-SXM manufactured by PHI USA ・ Excitation X-ray: monochromatic AlKα1,2 line (1486.6 eV)
・ X-ray diameter: 100 (μm)
-Photoelectron escape angle: 45 °
-Raster area: 2 x 2 (mm)
Ar ion etching: 2.0 (kV) 1.5 × 10 ⁻⁷ (Torr)
Sputtering speed: 3.68 nm / min (Si ₂ O conversion value)
-Data processing: 9-point smoothing
Atomic information is obtained from the peak binding energy value, and the composition is quantified (at.%) Using the area ratio of each peak. Among them, the oxygen atom ratio is defined as the oxygen concentration. Furthermore, the peak of the metal atom can be divided into the respective peak of the bonded state according to the bonding state (metal-oxygen, metal-hydroxyl group, metal-metal, etc.), and the respective bonding states are in the respective bonding states from the area ratio of the respective bonding state peaks. Quantify the abundance ratio of metal atoms [at. %]can do. Atomic% indicates the number of metal elements in the bonded state per 100 metal atoms. For example, when the metal component of the M layer is aluminum, a metal bond (Al—Al), an aluminum-oxygen bond (Al ₂ O ₃ ), an aluminum-oxygen-hydroxyl bond (AlOOH), an aluminum-hydroxyl bond (Al (OH)) ₃ ) It can be divided into four types of aluminum atoms having a bonding state. The abundance ratio of aluminum bonded to a hydroxyl group in the present invention is the abundance ratio of the fourth aluminum-hydroxyl bond (Al (OH) ₃ ).

  The peak splitting of the combined state is performed with reference to B. Vincent Crist Handbook of Monochromatic XPS Spectra (October 2000, published by Wiley).

(6) Total light transmittance Based on JIS-K7105 (1981), a support body is measured using the following measuring apparatus. The average value of five measurement results is defined as the total light transmittance in the present invention.
・ Measurement device: Direct reading haze meter HGM-2DP (for C light source) Suga Test Instruments Co., Ltd. ・ Light source: Halogen lamp 12V, 50W
-Light receiving characteristics: 395 to 745 nm
・ Measurement environment: Temperature 23 ℃ Humidity 65% RH
-Number of measurements: Measure 5 times.

(7) Surface resistivity Since the measurable device differs depending on the range of surface resistivity, first, the support is measured by the method of i), and the sample whose surface resistivity is too low to be measured Measure by method. The average value of five measurement results is defined as the surface resistivity in the present invention.

i) Low resistivity measurement Measured using the following measuring device in accordance with JIS-K7194 (1994).
・ Measurement device: Lorester EP MCP-T360, manufactured by Mitsubishi Chemical ・ Measurement environment: temperature 23 ° C., humidity 65% RH
-Number of measurements: Measure 5 times.

ii) High resistivity measurement Measured using the following measuring device in accordance with JIS-C2151 (1990).
・ Measuring device: Digital ultra-high resistance / micro ammeter R8340 manufactured by Advantest Corporation ・ Applied voltage: 100V
・ Application time: 10 seconds ・ Measurement unit: Ω
・ Measurement environment: Temperature 23 ℃ Humidity 65% RH
-Number of measurements: Measure 5 times.

(8) Glass transition temperature (Tg)
Specific heat is measured with the following equipment and conditions, and determined according to JIS K7121 (1987).
・ Device: Temperature modulation DSC manufactured by TA Instrument
·Measurement condition:
・ Heating temperature: 270-570K (RCS cooling method)
・ Temperature calibration: Melting point of high purity indium and tin ・ Temperature modulation amplitude: ± 1K
・ Temperature modulation period: 60 seconds ・ Temperature increase step: 5K
・ Sample weight: 5mg
Sample container: Aluminum open container (22 mg)
Reference container: Aluminum open container (18mg)
The glass transition temperature is calculated by the following formula.
Glass transition temperature = (extrapolated glass transition start temperature + extrapolated glass transition end temperature) / 2.

(9) Melting point (Tm)
Using a DSC (RDC220) manufactured by Seiko Instruments Inc. as a differential scanning calorimeter and a disk station (SSC / 5200) manufactured by Seiko Instruments Inc. as a data analysis device, about 5 mg of a sample is melted and held at 300 ° C. for 5 minutes on an aluminum tray, and rapidly cooled and solidified. After that, the temperature is raised from room temperature at a heating rate of 20 ° C./min. At that time, the peak temperature of the endothermic peak of melting observed is defined as the melting point (Tm).

  Further, the minute peak observed just before the melting point is defined as the minute melting peak temperature of the base film.

(10) Dimensional stability of film The film to be measured is bonded to the film side of the copper-clad polyimide film described in JIS C-6472 with an adhesive composed of a general-purpose vinyl chloride resin and a plasticizer, and the temperature is 160 ° C. And pressure was applied using a roll under the conditions of 2.9 MPa (30 kg / cm ² ) and 30 minutes. A sample of 25 cm in the MD direction × 25 cm in the TD direction was cut out from the obtained pressure-bonded film and placed on a surface plate. In that state, the curled state at the four corners was observed, and the average value of the warping amounts (mm) at the four corners was obtained. Evaluation was made according to the following criteria.

  A: The amount of warpage is less than 5 mm.

      ○: The amount of warpage is 5 mm or more and less than 10 mm.

      (Triangle | delta): The curvature amount is 10 mm or more and less than 15 mm.

  X: The amount of warpage is 15 mm or more.

(11) Crack resistance A tensile tester is used to pull the composite film with a certain amount of elongation, and then the surface state is observed with a differential interference microscope. The conditions are as follows.
(Tensile testing machine)
・ Measuring device: Automatic tensile strength measuring device “Tensilon AMF / RTA-100” manufactured by Orientec Co., Ltd.
Sample size: support width direction 12.6 mm × support length direction 100 mm,
・ Tensile speed: 10% / min ・ Tensile elongation: Ten points in 0.5% increments in the range of 0.5% to 5% ・ Measurement environment: Temperature 23 ° C., humidity 65% RH
(Differential interference microscope)
・ Measuring device: Leica DMLB HC Leica Microsystems Co., Ltd. ・ Observation magnification: 1000 times Ten samples pulled at each elongation were prepared, and 10 fields of view were randomly observed for each sample and cracked on the surface. If a total of 8 or more cracks that can be judged as tears are observed, a crack is present. Then, the crack resistance is evaluated according to the following criteria. X is rejected.
◎: When cracks do not occur at an elongation of 5% ○: When cracks occur at an elongation of 2% or more and less than 5% △: When a crack occurs at an elongation of 1% or more but less than 2% ×: 1% of elongation If a crack occurs at less than

  Based on the following examples, embodiments of the present invention will be described. Here, polyethylene terephthalate is expressed as PET, and poly (ethylene-2,6-naphthalenedicarboxylate) is expressed as PEN. The present invention is not limited to these.

(Example 1)
194 parts by weight of dimethyl terephthalate and 124 parts by weight of ethylene glycol were charged into a transesterification reactor, and the contents were dissolved by heating to 140 ° C. Thereafter, 0.1 parts by weight of magnesium acetate tetrahydrate and 0.05 part by weight of antimony trioxide were added while stirring the contents, and a transesterification reaction was carried out while distilling methanol at 140 to 230 ° C. Next, 1 part by weight of a 5 wt% ethylene glycol solution of trimethyl phosphate (0.05 parts by weight as trimethyl phosphate) was added.

  Addition of trimethyl phosphoric acid in ethylene glycol reduces the temperature of the reaction contents. Therefore, stirring was continued until the temperature of the reaction contents returned to 230 ° C. while distilling excess ethylene glycol. When the temperature of the reaction contents in the transesterification reactor thus reached 230 ° C., the reaction contents were transferred to the polymerization apparatus.

  After the transition, the reaction system was gradually heated from 230 ° C. to 290 ° C. and the pressure was reduced to 0.1 kPa. The time to reach the final temperature and final pressure was both 60 minutes. After reaching the final temperature and final pressure, the reaction was carried out for 2 hours (3 hours after the start of polymerization). The value indicated by polyethylene terephthalate having an intrinsic viscosity of 0.62 was a predetermined value). Accordingly, the reaction system was purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged into cold water in a strand form, and immediately cut to obtain polyethylene terephthalate PET pellets X having an intrinsic viscosity of 0.62.

  A bent-type twin-screw kneading extruder of the same direction type provided with three kneading paddle kneading sections heated to 300 ° C. (manufactured by Nippon Steel, screw diameter 30 mm, screw length / screw diameter = 45.5) The obtained PET pellet X is 50% by weight and the pellet of polyetherimide “Ultem 1010” made by GE Plastics is supplied by 50% by weight, melt-extruded at a screw speed of 300 revolutions / minute, and discharged in a strand shape at a temperature of 25 ° C. After cooling with water, cutting was performed immediately to prepare a blend chip (I).

  Further, in the same direction rotating type bent type twin screw kneader / extruder heated to 280 ° C., 98 parts by weight of PET pellet X and 20 parts by weight of water slurry of 10% by weight of spherical crosslinked polystyrene particles having an average diameter of 0.3 μm. (2 parts by weight as spherical crosslinked polystyrene) is supplied, the vent hole is maintained at a reduced pressure of 1 kPa or less, moisture is removed, and the intrinsic viscosity is 0.62 containing 2% by weight of spherical crosslinked polystyrene particles having an average diameter of 0.3 μm. PET pellet Y was obtained.

  To an extruder heated to a temperature of 295 ° C., 88.5 parts by weight of PET pellets X, 1.5 parts by weight of PET pellets Y and 10 parts by weight of blend chip (I) were dried under reduced pressure at 180 ° C. for 3 hours and then supplied. While applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C., it was closely cooled and solidified to produce an unstretched film. In addition, the glass transition temperature (Tg) of the unstretched film was 90 degreeC.

  The obtained unstretched film was stretched at a stretching temperature of 103 ° C. and a stretching ratio of 3.5 times in the longitudinal direction of the film using a longitudinal stretching machine composed of a plurality of heated roll groups and utilizing the peripheral speed difference of the rolls. And stretched. Thereafter, both ends of the film were gripped with clips and led to a tenter, and stretched in the width direction of the film at a stretching temperature of 105 ° C. and a stretching ratio of 3.7 times. Subsequently, after heat treatment at a temperature of 230 ° C. for 5 seconds, a relaxation treatment of 2% in the width direction was performed at a temperature of 180 ° C. to produce a biaxially oriented polyester film having a thickness of 50 μm. The biaxially stretched film had a glass transition temperature (Tg) of 115 ° C. and a melting point (Tm) of 255 ° C.

Next, after setting the polyester film obtained on the unwinding roll unit 13 of the vacuum vapor deposition apparatus 11 shown in FIG. 1 and reducing the pressure to 1.5 × 10 ⁻³ Pa, the cooling drum 16 at −20 ° C. The polyester film was run at a conveyance speed of 60 m / min and a conveyance tension of 100 N / m. At this time, aluminum having a purity of 99.99% by weight was evaporated by heating with an electron beam (output: 5.1 kW), and oxygen gas was supplied at 2.0 L / min from an oxygen supply nozzle 24 installed beside the crucible 23 as an evaporation source. Then, a vapor-deposited thin film layer (thickness: 100 nm) of aluminum oxide was formed on the B-side layer of the film and wound up. Next, a vapor-deposited thin film layer of aluminum oxide was provided on the A-side layer of the film in the same manner except that the transport tension was 80 N / m to obtain a composite film.
When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and excellent characteristics were obtained.

(Example 2)
A biaxially oriented polyester film was obtained in the same manner as in Example 1 except that the first stage of the heat treatment temperature was set to 205 ° C and the second stage was set to 180 ° C. Thereafter, in the same manner as in Example 1, a vapor-deposited thin film layer of aluminum oxide was provided to obtain a composite film. When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and excellent characteristics were obtained.

(Example 3)
A biaxially oriented polyester film was obtained in the same manner as in Example 1 except that the heat treatment step was performed at a temperature of 230 ° C. in only one stage. Thereafter, in the same manner as in Example 1, a vapor-deposited thin film layer of aluminum oxide was provided to obtain a composite film. When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and excellent characteristics were obtained.

Example 4
A biaxially oriented polyester film was obtained in the same manner as in Example 1 except that the first stage of the heat treatment temperature was set to 190 ° C and the second stage was set to 170 ° C. Thereafter, in the same manner as in Example 1, a vapor-deposited thin film layer of aluminum oxide was provided to obtain a composite film. When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and it had sufficient characteristics.

(Example 5)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 120 m / min, the oxygen gas introduction amount was 2.0 L / min, and the electron beam output was changed to 5.1 kW. The obtained composite film had excellent characteristics as shown in Tables 1 to 3.

(Example 6)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 25 m / min, the oxygen gas introduction amount was 2.0 L / min, and the electron beam output was changed to 5.1 kW. The obtained composite film had excellent characteristics as shown in Tables 1 to 3.

(Example 7)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 60 m / min, the oxygen gas introduction amount was changed to 3.2 L / min, and the electron beam output was changed to 6.1 kW. The obtained composite film had excellent characteristics as shown in Tables 1 to 3.

(Example 8)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 60 m / min, the oxygen gas introduction amount was changed to 6.0 L / min, and the electron beam output was changed to 6.1 kW. The obtained composite film had excellent characteristics as shown in Tables 1 to 3.

Example 9
To the extruder heated to a temperature of 280 ° C., 98.5 parts by weight of the PET pellet X obtained in Example 1 and 1.5 parts by weight of the PET pellet Y were dried at 180 ° C. for 3 hours under reduced pressure, and then supplied. While applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C., it was closely cooled and solidified to produce an unstretched film. In addition, the glass transition temperature (Tg) of the unstretched film was 80 degreeC.

  This unstretched film is stretched at a stretching temperature of 95 ° C. and a stretching ratio of 3.5 times in the longitudinal direction of the film using a longitudinal stretching machine composed of a plurality of heated roll groups and utilizing the peripheral speed difference of the rolls. did. Thereafter, both ends of the film were held with clips and guided to a tenter, and stretched in the width direction of the film at a stretching temperature of 100 ° C. and a stretching ratio of 3.7 times. Subsequently, after heat treatment at a temperature of 230 ° C. for 5 seconds, a relaxation treatment of 2% in the width direction was performed at a temperature of 170 ° C. to produce a biaxially oriented polyester film having a thickness of 50 μm. The biaxially stretched film had a glass transition temperature (Tg) of 105 ° C. and a melting point (Tm) of 255 ° C. Thereafter, in the same manner as in Example 1, a vapor-deposited thin film layer of aluminum oxide was provided to obtain a composite film. When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and excellent characteristics were obtained.

(Example 10)
A biaxially oriented polyester film having a thickness of 50 μm was produced in the same manner as in Example 10. Thereafter, in the same manner as in Example 7, an aluminum oxide vapor-deposited thin film layer was provided to obtain a composite film. When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and excellent characteristics were obtained.

(Example 11)
To a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol, 0.03 part by weight of manganese acetate tetrahydrate salt is added and gradually heated from 150 ° C. to 240 ° C. The transesterification was carried out while raising the temperature. In the middle, when the reaction temperature reached 170 ° C., 0.024 parts by weight of antimony trioxide was added. When the reaction temperature reached 220 ° C., 0.042 parts by weight (corresponding to 2 mmol%) of 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt was added. Thereafter, a transesterification reaction was carried out, and 0.023 part by weight of trimethyl phosphoric acid was added. Next, the reaction product is transferred to a polymerization apparatus, heated to a temperature of 290 ° C., subjected to a polycondensation reaction under a high vacuum of 30 Pa, and the stirring torque of the polymerization apparatus is a predetermined value (specifically depending on the specifications of the polymerization apparatus). Although this value was different, the value indicated by polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.65 in this polymerization apparatus was a predetermined value). Therefore, the reaction system was purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged into cold water in the form of strands, and immediately cut to obtain PEN (polyethylene-2,6-naphthalate) pellets P with an intrinsic viscosity of 0.65. It was.

  In the same direction rotation type bent type twin-screw kneading extruder heated to 280 ° C., 98 parts by weight of pellets P and 20 parts by weight of 10 wt% water slurry of spherical crosslinked polystyrene particles having an average diameter of 0.3 μm (spherical crosslinked) PEN pellet Q having an intrinsic viscosity of 0.65 and containing 2% by weight of spherical cross-linked polystyrene particles having an average diameter of 0.3 μm, the vent hole being maintained at a reduced pressure of 1 kPa or less to remove water, and 2% by weight of spherical crosslinked polystyrene particles having an average diameter of 0.3 μm. Got.

  To the extruder heated to 280 ° C., 98.5 parts by weight of PEN pellets P and 1.5 parts by weight of PEN pellets Q were dried under reduced pressure at 180 ° C. for 3 hours and then supplied. While applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C., it was closely cooled and solidified to produce an unstretched film. The glass transition temperature (Tg) of the unstretched film was 120 ° C.

  The obtained unstretched film was stretched at a stretching temperature of 135 ° C. and a stretching ratio of 4.0 times in the longitudinal direction of the film using a longitudinal stretching machine composed of a plurality of heated roll groups and utilizing the peripheral speed difference of the rolls. And stretched. Thereafter, both ends of the film were held with clips and guided to a tenter, and stretched in the width direction of the film at a stretching temperature of 140 ° C. and a stretching ratio of 5.0 times. Subsequently, after heat treatment at a temperature of 240 ° C. for 5 seconds, a relaxation treatment of 2% in the width direction was performed at a temperature of 180 ° C. to produce a biaxially oriented polyester film having a thickness of 50 μm. The biaxially stretched film had a glass transition temperature (Tg) of 135 ° C. and a melting point (Tm) of 265 ° C.

  Thereafter, a composite film was obtained in the same manner as in Example 1. The obtained composite film had excellent characteristics as shown in Tables 1 to 3.

(Example 12)
A biaxially oriented polyester film having a thickness of 50 μm was produced in the same manner as in Example 12. The following was carried out similarly to Example 7, and provided the vapor-deposited thin film layer of aluminum oxide, and obtained the support body for magnetic recording media. When the obtained composite film was evaluated, as shown in Tables 1 to 3, the dimensional change rate was small and excellent characteristics were obtained.

(Example 13)
Implemented except that the metal material in the vapor deposition process was changed to zinc with a purity of 99.9999% by weight, the transfer speed was 60 m / min, the oxygen gas introduction amount was 2.5 L / min, and the electron beam output was 5.8 kW. A composite film was obtained in the same manner as in Example 1. The obtained composite film had excellent characteristics as shown in Tables 1 to 3.

(Example 14)
The polyester film obtained in Example 1 is set on the unwinding roll portion 113 of the vacuum vapor deposition apparatus 111 shown in FIG. 2, and after the pressure is reduced to 1.5 × 10 ⁻³ Pa, the cooling drum 116 at −20 ° C. The polyester film was run at a transport speed of 60 m / min and a transport tension of 100 N / m. At this time, aluminum having a purity of 99.99% by mass was evaporated by heating with an electron beam (output 5.1 kW), and oxygen gas was supplied at 8.0 L / min from an oxygen supply nozzle 124 installed beside the crucible 123 as an evaporation source. Then, a vapor-deposited thin film layer (thickness 40 nm) of aluminum oxide was formed on the B-side layer of the film and wound up. Next, a vapor-deposited thin film layer of aluminum oxide was provided on the A-side layer of the film in the same manner except that the transport tension was 80 N / m to obtain a composite film. The obtained composite film had the characteristics shown in Tables 1 to 3.

(Example 15)
A composite film was obtained in the same manner as in Example 14 except that the conveyance speed in the vapor deposition step was changed to 60 m / min, the oxygen gas introduction amount was changed to 0.5 L / min, and the electron beam output was changed to 6.1 kW. The obtained composite film had the characteristics shown in Tables 1 to 3.

(Comparative Example 1)
A composite film was obtained in the same manner as in Example 1 except that the vapor-deposited thin film layer was not provided on the biaxially oriented polyester film having a thickness of 50 μm obtained in Example 1. The obtained composite film did not have a metal oxide layer (M layer), and had characteristics as shown in Tables 1 to 3.

(Comparative Example 2)
A composite film was obtained in the same manner as in Example 1 except that oxygen gas was not supplied in the vapor deposition step. The obtained composite film did not have an aluminum oxide layer, and had characteristics insufficient for dimensional stability as shown in Tables 1 to 3.

(Comparative Example 3)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 60 m / min, the oxygen gas introduction amount was changed to 10.0 L / min, and the electron beam output was changed to 8.0 kW. As shown in Tables 1 to 3, the obtained composite film had insufficient characteristics for dimensional stability.

(Comparative Example 4)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 250 m / min, the oxygen gas introduction amount was changed to 4.0 L / min, and the electron beam output was changed to 1.3 kW. As shown in Tables 1 to 3, the obtained composite film had insufficient characteristics for dimensional stability.

(Comparative Example 5)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 15 m / min, the oxygen gas introduction amount was changed to 3.0 L / min, and the electron beam output was changed to 3.3 kW. As shown in Tables 1 to 3, the obtained composite film had insufficient characteristics for dimensional stability.

(Comparative Example 6)
A composite film was obtained in the same manner as in Example 1 except that the conveyance speed in the vapor deposition step was changed to 60 m / min and the oxygen gas introduction amount was changed to 1.0 L / min. As shown in Tables 1 to 3, the obtained composite film had insufficient characteristics for dimensional stability.

It is a schematic diagram of the vacuum evaporation apparatus used suitably when manufacturing the support body of this invention. It is a schematic diagram of the vacuum evaporation system used when manufacturing the support body of this invention.

Explanation of symbols

1: Vacuum deposition apparatus 2: Vacuum chamber 3: Unwinding roll unit 4: Polyester film 5: Guide roll 6: Cooling drum 7: Deposition chamber 8: Winding roll unit 9: Metal material 10: Electron gun 11: Electron beam 12 : Oxygen gas cylinder 13: crucible 14: oxygen supply nozzle 15: mask 16: gas flow rate control device 111: vacuum deposition device 112: vacuum chamber 113: unwinding roll unit 114: polyester film 115: guide roll 116: cooling drum 117: deposition Chamber 118: Winding roll 119: Metal material 120: Electron gun 121: Electron beam 122: Oxygen gas cylinder 123: Crucible 124: Oxygen supply nozzle 125: Mask 126: Gas flow rate control device

Claims (9)

A biaxially oriented polyester film having a layer (M layer) containing a metal-based oxide on at least one side, wherein the total light transmittance of the film is in the range of 10 to 75%, and the frequency in the longitudinal direction of the film In the dynamic viscoelasticity measured at 1 Hz, a composite film having a ratio of (storage modulus at a temperature of 60 ° C.) / (Storage modulus at a temperature of 160 ° C.) of 1.5 to 5.0. 2. The composite film according to claim 1, wherein the surface resistivity of the layer containing metal oxide (M layer) is in the range of 1 × 10 ³ to 1 × 10 ¹³ Ω. The composite film according to claim 1 or 2, wherein the layer containing the metal-based oxide (M layer) has a thickness of 30 to 200 nm. Using a differential scanning calorimeter of a biaxially oriented polyester film, when the temperature is increased from room temperature at a rate of temperature increase of 20 ° C./min, the peak temperature of the endothermic peak of melting observed is the melting point (Tm) and observed immediately before the melting point. The composite film according to any one of claims 1 to 3, wherein a minute melting peak temperature just below the melting point is (melting point (Tm) -55) ° C to (Tm-15) ° C. The composite film according to any one of claims 1 to 4, which has a heat shrinkage rate of 0 to 1.0% at a temperature of 150 ° C in the longitudinal direction and the width direction of the composite film. The composite film according to any one of claims 1 to 5, wherein a temperature expansion coefficient at a temperature of 60 to 160 ° C in the longitudinal direction and the width direction of the composite film is 0 to 30 ppm / ° C. The metal element concentration of the M layer is 30 to 60 at. The composite film according to claim 1, which is%. The abundance ratio of metal atoms in the M layer that are metal-bonded is 1 to 20 at. The composite film according to claim 1, which is%. The metal oxide of the M layer is aluminum oxide, and the abundance ratio of aluminum atoms bonded to hydroxyl groups is 0 to 50 at. The composite film according to claim 1, which is%.

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