JP2018079670A - Polyarylate film laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for suppressing curl of a polyarylate film under high temperature environment.SOLUTION: The polyarylate film laminate has a stress relaxation layer containing a silicon atom, an oxygen atom and a carbon atom on at least one surface of a polyarylate film. The polyarylate film has an average value of tensile elasticity at 23°C in a direction A in which refractive index becomes maximum in a film surface and tensile elasticity at 23°C in a direction B orthogonal to the direction A, of 2.5 GPa to 4.5 GPa, and an absolute value of difference between the tensile elasticity in the A direction and the tensile elasticity in the B direction of 1.5 GPa or less. Average of percentage (%) of peak intensity derived from C-C bonds to peak intensity derived from C-C, C-SiO, C-O, C=O and O-C-O bonds at each measurement position, calculated from depth profiles of C1s spectrum area measured by an X-ray photoelectron spectroscopy of the stress relaxation layer, is 1% or more.SELECTED DRAWING: None

Description

  The present invention relates to a polyarylate film laminate. More specifically, the present invention relates to a technique for suppressing curling of a polyarylate film in a high temperature environment.

  A flexible printed circuit board (FPC) generally has a structure in which a conductor circuit is disposed on a base film (insulating substrate) and further covered with a coverlay film.

  In recent years, in FPCs used for applications such as LED lighting, transparency of a base film and a cover film is required from the viewpoint of emphasizing design.

  Further, when manufacturing an FPC, an element such as an LED is mounted on a base film through a reflow soldering process (hereinafter also simply referred to as “reflow process”). Since the base film is exposed to a high temperature (about 250 ° C. at the maximum) in the reflow process, the base film is required to have high heat resistance that can withstand this temperature.

  Conventionally, polyimide films have been widely used as such FPC base films and cover films. In recent years, it has been proposed to use a polyarylate film that can exhibit higher transparency and heat resistance as a base film or a cover film.

  In Patent Document 1, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene residue and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) as structural units derived from dihydric phenol A polyarylate having a propane residue, a terephthalic acid residue as a structural unit derived from a dicarboxylic acid component, and an isophthalic acid residue in a predetermined ratio is disclosed. According to the document, polyarylate having excellent transparency, heat resistance, and low birefringence can be obtained by adopting the above configuration.

  In patent document 2, it has a predetermined glass transition temperature and a haze value, and the tensile elastic modulus at 23 ° C. in the direction A in which the refractive index is maximum in the film plane, and the tensile at 23 ° C. in the direction B orthogonal to the direction A. Polyarylate film having an average value of elastic modulus of 2.5 GPa or more and 4.5 GPa or less, and an absolute value of a difference between tensile elastic modulus in direction A and tensile elastic modulus in direction B being 1.5 GPa or less Is disclosed. According to the said literature, it is supposed that it can be set as the polyarylate film which has favorable handling property in addition to high transparency and heat resistance by setting it as the said structure.

Japanese Patent No. 4551503 Japanese Patent Laid-Open No. 2006-112773

  However, the polyarylate films described in Patent Documents 1 and 2 have a problem of curling when exposed to high temperatures in the reflow process described above.

  Then, an object of this invention is to provide the means which suppresses the curl of the polyarylate film in a high temperature environment.

  The present inventors have intensively studied to solve the above problems. As a result, a stress relaxation layer containing silicon atoms, oxygen atoms and carbon atoms is formed on at least one surface of the polyarylate film, and the ratio of C—C bonds in the stress relaxation layer is controlled within a predetermined range. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.

  That is, the polyarylate film laminate of the present invention has a stress relaxation layer containing silicon atoms, oxygen atoms and carbon atoms on at least one surface of the polyarylate film. In the polyarylate film, the average value of the tensile elastic modulus at 23 ° C. in the direction A where the refractive index is maximum in the film plane and the tensile elastic modulus at 23 ° C. in the direction B orthogonal to the direction A is 2.5 GPa or more 4 The absolute value of the difference between the tensile modulus in direction A and the tensile modulus in direction B is 1.5 GPa or less. Then, C—C, C—SiO, C—O, C═O and O—C—O at each measurement position obtained from the depth profile of the C1s spectral region measured by the X-ray photoelectron spectroscopy of the stress relaxation layer. The average value of the ratio (%) of the peak intensity derived from the C—C bond to the peak intensity derived from each bond is 1% or more.

  According to the present invention, a means for suppressing curling of a polyarylate film under a high temperature environment is provided.

It is a schematic diagram which shows an example of the manufacturing apparatus of a polyarylate film. It is a schematic diagram which shows an example of the plasma CVD apparatus used for formation of a stress relaxation layer.

  A polyarylate film laminate (hereinafter also simply referred to as “laminate”) according to an embodiment of the present invention has a stress relaxation layer containing silicon atoms, oxygen atoms, and carbon atoms on at least one surface of the polyarylate film. . In the polyarylate film, the average value of the tensile elastic modulus at 23 ° C. in the direction A where the refractive index is maximum in the film plane and the tensile elastic modulus at 23 ° C. in the direction B orthogonal to the direction A is 2.5 GPa or more 4 The absolute value of the difference between the tensile modulus in direction A and the tensile modulus in direction B is 1.5 GPa or less. Then, C—C, C—SiO, C—O, C═O and O—C—O at each measurement position obtained from the depth profile of the C1s spectral region measured by the X-ray photoelectron spectroscopy of the stress relaxation layer. The average value of the ratio (%) of the peak intensity derived from the C—C bond to the peak intensity derived from each bond is 1% or more.

  According to the polyarylate film laminate of the present embodiment, it is possible to suppress curling of the polyarylate film under a high temperature (for example, 200 ° C.) environment. Although the reason why curling of the polyarylate film in a high temperature environment is suppressed by having the above configuration is not clear, the present inventors presume as follows.

  First, in the polyarylate film laminate of this embodiment, a stress relaxation layer containing silicon atoms, oxygen atoms and carbon atoms and having a C—C bond at a predetermined ratio is formed on at least one surface of the polyarylate film. It is characterized by being made. When the polyarylate film is exposed to a high temperature, curling occurs due to heat shrinkage, but the stress relaxation layer is considered to play a role of relaxing the compressive stress at this time. In particular, among all the bonds (C—C, C—SiO, C—O, C═O, and O—C—O) in which the carbon atoms contained in the stress relaxation layer are involved, the ratio of C—C bonds is set to 1. By setting it as% or more, flexibility is imparted to the stress relaxation layer, and the compressive stress of the polyarylate film can be sufficiently relaxed.

  Further, the laminate of this embodiment has a tensile elastic modulus at 23 ° C. in the direction A (normally the maximum stretching direction) in which the refractive index is maximum in the film plane, and a tensile elasticity at 23 ° C. in the direction B perpendicular to the direction A. The average value of the modulus is 2.5 GPa or more and 4.5 GPa or less, and the absolute value of the difference between the tensile modulus in direction A and the tensile modulus in direction B is 1.5 GPa or less. . If the average value of the tensile modulus and the absolute value of the difference are within the above ranges, the compressive stress of the polyarylate film in a high temperature environment does not become too large. It is considered that the stress can be relaxed sufficiently. However, the above mechanism is just a guess, and the present invention should not be construed in a limited manner by the above mechanism.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) and relative humidity of 40 to 50% RH or less.

<Polyarylate film laminate>
The polyarylate film laminate of this embodiment is characterized in that a stress relaxation layer having a C—C bond at a predetermined ratio is provided on at least one surface of a polyarylate film having a predetermined tensile elastic modulus. Hereinafter, the polyarylate film and the stress relaxation layer according to this embodiment will be described in detail.

<Polyarylate film>
A polyarylate film (hereinafter also simply referred to as “film”) contains polyarylate as a main component.

[Polyarylate]
The polyarylate contains at least a structural unit derived from an aromatic dialcohol component and a structural unit derived from an aromatic dicarboxylic acid component.

(Structural unit derived from aromatic dialcohol component)
The aromatic dialcohol for obtaining the structural unit derived from the aromatic dialcohol component is preferably a bisphenol represented by the following formula (1), more preferably a bisphenol represented by the following formula (1 ′). .

L in the general formulas (1) and (1 ′) is a divalent group. The divalent group is preferably a single bond, an alkylene group, —S—, —SO—, —SO ₂ —, —O—, —CO— or —CR ₁ R ₂ — (R ₁ and R ₂ are bonded to each other. To form an aliphatic ring or an aromatic ring.

  The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, and an isopropylidene group. The alkylene group may further have a substituent such as a halogen atom or an aryl group.

R ₁ and R ₂ of —CR ₁ R ₂ — are bonded to each other to form an aliphatic ring or an aromatic ring. The aliphatic ring is preferably an aliphatic hydrocarbon ring having 5 to 20 carbon atoms, and preferably a substituted or unsubstituted cyclohexane ring. The aromatic ring is an aromatic hydrocarbon ring having 6 to 20 carbon atoms, and preferably a substituted or unsubstituted fluorene ring. Examples of —CR ₁ R ₂ — forming a substituted or unsubstituted cyclohexane ring include cyclohexane-1,1-diyl group, 3,3,5-trimethylcyclohexane-1,1-diyl group and the like. It is. Examples of —CR ₁ R ₂ — forming a substituted or unsubstituted fluorene ring include a fluorenediyl group represented by the following formula.

  R in the general formulas (1) and (1 ′) may independently be an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. n is independently an integer of 0 to 4, preferably an integer of 0 to 3.

  Examples of bisphenols in which L is an alkylene group include 1,1-bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-methyl-2 -Hydroxyphenyl) methane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4- Hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA), etc. Is included. Among them, 2,2-bis (4-hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2-bis (3,5-dimethyl- Isopropylidene-containing bisphenols such as 4-hydroxyphenyl) propane (TMBPA) are preferred.

Examples of bisphenols in which L is —S—, —SO— or —SO ₂ — include bis (4-hydroxyphenyl) sulfone, bis (2-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4 -Hydroxyphenyl) sulfone (TMBPS), bis (3,5-diethyl-4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) sulfone, Bis (4-hydroxyphenyl) sulfide, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, bis (3,5-diethyl-4-hydroxyphenyl) sulfide, bis (3-methyl-4-hydroxyphenyl) Sulfide, bis (3-ethyl-4-hydroxyphenyl) sulfide, 2,4-dihydride Carboxymethyl diphenyl sulfone and the like. Examples of bisphenols where L is —O— include 4,4′-dihydroxydiphenyl ether; examples of bisphenols where L is —CO— include 4,4′-dihydroxydiphenyl ketone. .

Examples of bisphenols in which L is —CR ₁ R ₂ — and R ₁ and R ₂ are bonded to each other to form an aliphatic ring include 1,1-bis (4-hydroxyphenyl) cyclohexane (BPZ) And bisphenols having a cyclohexane skeleton such as 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (BPTMC).

Examples of bisphenols in which L is —CR ₁ R ₂ — and R ₁ and R ₂ are bonded to each other to form an aromatic ring include 9,9-bis (3-methyl-4-hydroxyphenyl) Bisphenols having a fluorene skeleton such as fluorene (BCF) and 9,9-bis (3,5-dimethyl-4-hydroxyphenyl) fluorene (BXF) are included.

  The aromatic dialcohol component constituting the polyarylate may be one kind or two or more kinds.

Among these, from the viewpoint of enhancing the solubility of the resin in the solvent or enhancing the adhesion of the film to the metal, for example, a sulfur atom (—S—, —SO— or —SO ₂ —) is present in the main chain. Bisphenols contained are preferred. From the viewpoint of enhancing the heat resistance of the film, for example, bisphenols containing a sulfur atom in the main chain and bisphenols having a cycloalkylene skeleton are preferred. From the viewpoint of reducing the birefringence of the film or improving the wear resistance, bisphenols having a fluorene skeleton are preferred.

  Bisphenols having a cyclohexane skeleton and bisphenols having a fluorene skeleton are preferably used in combination with bisphenols containing an isopropylidene group. In that case, the content ratio of the bisphenol having a cyclohexane skeleton or the bisphenol having a fluorene skeleton and the bisphenol having an isopropylidene group is 10/90 to 90/10 (molar ratio), preferably 20/80 to 80/20 (molar ratio).

  The polyarylate may further contain a structural unit derived from an aromatic polyhydric alcohol component other than the aromatic dialcohol component as long as the effects of the present invention are not impaired. Examples of the aromatic polyhydric alcohol component include compounds described in paragraph “0015” of Japanese Patent No. 4551503. Specifically, tris (4-hydroxyphenyl) methane, 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, 2,3, 4,4′-tetrahydroxybenzophenone, 4- [bis (4-hydroxyphenyl) methyl] -2-methoxyphenol, tris (3-methyl-4-hydroxyphenyl) methane and the like are included. The content ratio of the structural unit derived from these aromatic polyhydric alcohol components can be appropriately set according to the required characteristics, but the structural unit derived from the aromatic dialcohol component and other aromatic polyhydric alcohol components derived from it For example, it may be 5 mol% or less with respect to the total of the structural units.

(Constitutional unit derived from aromatic dicarboxylic acid component)
The aromatic dicarboxylic acid for obtaining the structural unit derived from the aromatic dicarboxylic acid component may be terephthalic acid, isophthalic acid or a mixture thereof.

  From the viewpoint of enhancing the mechanical properties of the film, a mixture of terephthalic acid and isophthalic acid is preferable. The content ratio of terephthalic acid and isophthalic acid is preferably terephthalic acid / isophthalic acid = 90/10 to 10/90 (molar ratio), more preferably 70/30 to 30/70, and still more preferably 50/50. When the content ratio of terephthalic acid is in the above range, a polyarylate having a sufficient degree of polymerization is easily obtained, and a film having sufficient mechanical properties is easily obtained.

  The polyarylate may further contain a structural unit derived from an aromatic dicarboxylic acid component other than terephthalic acid and isophthalic acid as long as the effects of the present invention are not impaired. Examples of such aromatic dicarboxylic acid components include orthophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenic acid, 4,4′-dicarboxydiphenyl ether, bis (p-carboxyphenyl) alkane, 4,4′- Dicarboxyphenyl sulfone and the like are included. The content ratio of the structural unit derived from the aromatic dicarboxylic acid component other than terephthalic acid and isophthalic acid can be appropriately set according to the required characteristics, but the terephthalic acid component, the structural unit derived from the isophthalic acid component and other aromatics For example, it may be 5 mol% or less with respect to the total of the structural units derived from the dicarboxylic acid component.

(Glass-transition temperature)
The glass transition temperature (Tg) of the polyarylate is preferably 260 ° C. or higher and 350 ° C. or lower, more preferably 265 ° C. or higher and lower than 300 ° C., further preferably 270 ° C. or higher and lower than 300 ° C.

  The glass transition temperature of polyarylate can be measured according to JIS K7121 (1987). Specifically, using a DSC 6220 manufactured by Seiko Instruments Inc. as a measuring device, it can be measured under conditions of 10 mg of a polyarylate sample and a heating rate of 20 ° C./min.

  The glass transition temperature of the polyarylate can be adjusted by the type of aromatic dialcohol component constituting the polyarylate. In order to increase the glass transition temperature, for example, it is preferable to include “a unit derived from a bisphenol having a sulfur atom in the main chain” as a structural unit derived from an aromatic dialcohol component.

(Intrinsic viscosity)
The intrinsic viscosity of the polyarylate is preferably 0.3 to 1.0 dl / g, more preferably 0.4 to 0.9 dl / g, still more preferably 0.45 to 0.8 dl / g, and More preferably, it is 5-0.7 dl / g. When the intrinsic viscosity of polyarylate is 0.3 dl / g or more, the molecular weight of the resin composition tends to be a certain level or more, and a film having sufficient mechanical properties and heat resistance is easily obtained. When the intrinsic viscosity of the polyarylate is 1.0 dl / g or less, an excessive increase in the solution viscosity during film formation can be suppressed.

  Intrinsic viscosity can be measured according to ISO1628-1: 2009. Specifically, a solution in which a polyarylate sample is dissolved in 1,1,2,2-tetrachloroethane so as to have a concentration of 1 g / dl is prepared. The intrinsic viscosity of this solution at 25 ° C. is measured using an Ubbelohde type viscosity tube.

  The polyarylate production method may be a known method, preferably an interface in which an aromatic dicarboxylic acid halide dissolved in an organic solvent incompatible with water and an aromatic dialcohol dissolved in an alkaline aqueous solution are mixed. It may be a polymerization method (W. M. EARECKSON, J. Poly. Sci. XL399, 1959, Japanese Patent Publication No. 40-1959).

  The content of polyarylate is 50% by mass or more, preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, based on the whole polyarylate film. Most preferably, it may be 100% by mass.

[Other ingredients]
Polyarylate film, if necessary, other resins other than polyarylate, additives such as heat stabilizer, antioxidant, light stabilizer, colorant, antistatic agent, lubricant, mold release agent, ultraviolet absorber May further be included.

[Physical properties of film]
The polyarylate film according to this embodiment can have an appropriate tensile elastic modulus (stiffness or strength) while having high transparency and heat resistance.

(Tensile modulus)
In the polyarylate film according to this embodiment, the average value of the tensile elastic modulus at 23 ° C. in the direction A in which the refractive index is maximum in the film plane and the tensile elastic modulus at 23 ° C. in the direction B orthogonal to the direction A is It is 2.5 GPa or more and 4.5 GPa or less. The average value of the tensile elastic modulus is more preferably 2.7 GPa or more and 4.0 GPa or less. When the average value of the tensile elastic modulus is less than 2.5 GPa, the stiffness or strength of the film is insufficient. Therefore, even when the stress relaxation layer is provided, curling can occur in a high temperature environment. If the average value of the tensile modulus exceeds 4.5 GPa, when the tension is applied and heated to near Tg, the residual stress of the film increases, so even in the case of having a stress relaxation layer, in a high temperature environment Curling can occur.

  In addition, the polyarylate film according to this embodiment is characterized in that the absolute value of the difference between the tensile elastic modulus in the direction A and the tensile elastic modulus in the direction B is 1.5 GPa or less. The absolute value of the difference in tensile elastic modulus is more preferably 1.0 GPa or less. When the difference in tensile elastic modulus is more than 1.5 GPa, the mechanical isotropy is low, and curling may occur when the film is exposed to high temperatures.

  Here, the “direction A in which the refractive index is maximum in the film plane” can be confirmed as a slow axis using an automatic birefringence meter KOBRA-21ADH or KOBRA-WR (Oji Scientific Instruments). . The angle θ between the “direction A in which the refractive index is maximum in the film plane” and the MD (Machine Direction) direction or TD (Transverse Direction) direction of the film is usually ± 1 ° or less, preferably ± 0.5. It can be below °. The “direction A in which the refractive index is maximum in the film plane” can be usually the maximum stretching direction.

  However, depending on the stretching conditions (for example, when the stretching ratios in the MD direction and the TD direction are the same), the “direction A in which the refractive index is maximum in the film plane” may not be confirmed. In that case, the direction A and the direction B can be any two orthogonal directions in the film plane.

  The tensile modulus can be measured by the method described in the examples described later in accordance with JIS K7127 (1999).

  The tensile elastic modulus can be adjusted by, for example, the drying temperature of the cast film during film formation and stretching conditions (stretching temperature and magnification). In order to increase the tensile modulus, for example, it is preferable to lower the drying temperature of the cast film or increase the draw ratio. In order to reduce the difference between the tensile elastic modulus in the direction A and the tensile elastic modulus in the direction B, for example, reduce the difference in the draw ratio in each direction (MD direction, TD direction) or perform bending treatment. Is preferred.

(Thickness)
The thickness of the polyarylate film depends on the use of the polyarylate film laminate, but may be, for example, 5 to 150 μm, preferably 10 to 80 μm, more preferably 10 to 60 μm, and still more preferably 15 to 50 μm.

<Method for producing polyarylate film>
The polyarylate film can be produced by a solution casting method. Specifically, the method for producing a polyarylate film includes 1) a step of obtaining a polymer solution by dissolving or dispersing the aforementioned polyarylate in a solvent having a boiling point of 70 ° C. or lower (a polymer solution preparation step), and 2) supporting the solution. And a step of obtaining a film-like product by drying (casting step) after casting on the body, and 3) a step of drawing the film-like product in two directions orthogonal to each other (stretching step) And / or 4) a bending process step. 4) The bending treatment step is preferably performed after 3) the stretching step.

  The production process of the polyarylate film can be performed by, for example, a production apparatus shown in FIG. FIG. 1 is a schematic diagram illustrating an example of a film manufacturing apparatus. The film manufacturing apparatus 100 can include a casting apparatus 120, a stretching apparatus 130, and a bending treatment apparatus 140.

1) Polymer solution preparation step Polyarylate is dissolved in a solvent to obtain a polymer solution. The solvent is preferably a solvent having a boiling point of 70 ° C. or less (preferably a good solvent) from the viewpoint of lowering the drying temperature of the cast film in the film-forming step described later.

  Examples of the good solvent having a boiling point of 70 ° C. or lower include methylene chloride (boiling point 40.4 ° C.), chloroform (boiling point 61.2 ° C.), and tetrahydrofuran (boiling point 66 ° C.). From the viewpoint of lowering the drying temperature in the film forming step, a good solvent having a boiling point of 60 ° C. or lower is preferable, and methylene chloride is more preferable.

  The polyarylate concentration in the polymer solution is preferably 10% by mass or more, and preferably about 10 to 30% by mass.

  It is preferable to remove insoluble matters and foreign matters from the polymer solution by filtration. The filter medium to be used may be of a level that can remove insoluble matters satisfactorily without causing clogging, and a filter medium having an absolute filtration accuracy of 0.008 mm or less, preferably 0.003 to 0.006 mm should be used. Is preferred.

2) Film-forming process After casting the obtained polymer solution from the die 121 of the casting apparatus 120 onto the metal support 123, the casting film is dried to obtain a film-like material (see FIG. 1).

  The metal support 123 can be an endless stainless steel belt conveyed by a roll 123A. The casting film is preferably dried so that the residual solvent amount at the start of stretching falls within the range described below.

  The casting membrane can be dried by various methods, for example, by adjusting the surface temperature of the metal support 123 and applying air to the casting membrane. The surface temperature of the metal support 123 can be controlled by, for example, a method of bringing warm water into contact with the back side of the metal support.

  In the production of the polyarylate film according to this embodiment, it is preferable to lower the drying temperature of the cast film on the belt (the surface temperature of the metal support 123 and the temperature of the wind W). By lowering the drying temperature of the cast film on the belt, a film-like product having a high tensile elastic modulus can be obtained. As described above, it is presumed that the stacking (orientation) between the resin molecules efficiently proceeds with drying and the plane orientation increases.

  However, if the drying temperature (the surface temperature of the metal support 123 and the temperature of the wind W) is too low, not only will the drying time be prolonged, but too much low temperature wind will be blown, and the film surface tends to become rough due to condensation, Transparency may be impaired. If the drying temperature is too high, the polymer molecules are likely to be random in the solution, so that the polyarylate molecules are difficult to stack (orientate), and the tensile modulus of the resulting film is difficult to increase.

  Therefore, the drying temperature of the cast film, specifically, the surface temperature of the metal support 123 and the temperature of the wind applied to the cast film are each preferably less than 80 ° C., and preferably 5 to 70 ° C. 10 to 60 ° C is more preferable, and 15 to 40 ° C is still more preferable. Drying may be performed at a time, or may be performed stepwise by changing the temperature.

  The film-like material obtained after drying is peeled off from the metal support 123 with a peeling roll 125 or the like.

3) Stretching step From the viewpoint of improving the tensile modulus of the film, it is preferable to stretch the obtained film-like product. Stretching is preferably performed in two directions orthogonal to each other (that is, biaxial stretching) from the viewpoint of reducing the anisotropy of orientation of resin molecules. The two directions orthogonal to each other may preferably be the MD direction and the TD direction.

  Stretching in two directions orthogonal to each other may be performed simultaneously or sequentially. Although simultaneous biaxial stretching may be performed, it is very difficult to make the orientation angle uniform over the entire film surface, and therefore it is preferable to perform sequential biaxial stretching. When performing sequential biaxial stretching, it is preferable to stretch the peeled film in the MD direction and then in the TD direction.

  The draw ratio in each direction is preferably 1.05 to 2.5 times, and more preferably 1.2 to 2.0 times. The draw ratio is represented by the ratio of the stretched film (stretching direction) length to the stretched film (stretching direction) length (stretched film length / stretched film length). The The sum (total) of the draw ratios in each direction is preferably 2.2 to 4.0 times, and more preferably 2.2 to 3.5 times. When the sum of the draw ratios is 2.2 times or more, the tensile elastic modulus of the film can be sufficiently increased. When the sum of the draw ratios is 4.0 times or less, an excessive increase in haze can be suppressed. In order to obtain a film having high optical isotropy, the difference in the draw ratio in each direction is preferably small, and the difference in the draw ratio in each direction is preferably 0.5 times or less.

  When the draw ratio is increased, the orientation of the resin molecules is easily aligned, so that the tensile elastic modulus of the film is easily increased, and the haze is easily increased. In order to increase the tensile elastic modulus while suppressing an increase in haze, it is effective to increase the tensile elastic modulus of the film before stretching, that is, to lower the drying temperature of the cast film in the film forming process. It is.

  The stretching temperature is preferably (Tg-130) to (Tg-20) ° C, and (Tg-110 ° C) to (Tg-30) ° C, where Tg is the glass transition temperature of the polyarylate. Is more preferable. By stretching at the above temperature and magnification, a sufficient stretching stress can be imparted to the film, so that the tensile elastic modulus of the resulting film can be effectively increased. The amount of residual solvent in the film-like material at the start of stretching, preferably the amount of residual solvent in the film-like material at the start of stretching in the MD direction after stretching in the TD direction is the viewpoint of suppressing an increase in haze. Therefore, the content is preferably 25 to 45% by mass, and more preferably 30 to 40% by mass. When the amount of residual solvent is a certain level or more, the film-like material becomes flexible, so that it is easy to stretch at a relatively high magnification. On the other hand, if the amount of residual solvent is below a certain level, the strength of the film-like material is stabilized, and uniform stretching is easy to perform.

  The amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
In the formula, M is the mass of the sample collected from the film-like material, and N is the mass after heating the sample at 150 ° C. for 1 hour.

  The stretching method is not particularly limited. Stretching in the MD direction can be performed, for example, by providing a peripheral speed difference between a plurality of rolls by a roll stretching device 131. Stretching in the TD direction can be performed, for example, by fixing both ends of the film-like material with clips or pins with a tenter stretching device 133 and widening the interval between the clips or pins in the TD direction (see FIG. 1).

4) Bending treatment step From the viewpoint of reducing the heat shrinkage rate of the film, it is preferable to bend the stretched film.

  The bending process can be performed by bending the film while being transported by a large number of transport rolls 147A and 147B in the heating atmosphere of the bending zone 141 (see FIG. 1). The bending is preferably performed by winding the film around a transport roll 147 so that one surface and the other surface of the film are alternately inside.

The diameters of the transport rolls 147A and 147B can be set to 90 to 108 mm, for example. The center-to-center distance between transport rolls adjacent in the film transport direction (for example, the center distance D between the transport roll 147A and the transport roll 147B in FIG. 1) depends on the film transport speed, but can be, for example, about 200 to 1800 mm. In order to sufficiently reduce the heat shrinkage rate of the obtained film, the value of 1 / a is 0.013 to 0.033 mm ⁻¹ , preferably 0.013, where amm is the radius when the film is bent. ~0.033mm ^-1, more preferably it may set the roll diameter so that 0.017~0.025mm ^-1.

  Hot air whose temperature is adjusted is introduced into the bending zone 141 from the intake port 143, flows through the bending zone 141, and is then exhausted from the exhaust port 145. The adjustment of the atmospheric temperature in the bending zone 141 may be performed by a heating roll or the like, but it is preferably performed by hot air because it is simple. The atmosphere in the bending zone 141 may be air, but may be an inert gas atmosphere such as nitrogen gas, carbon dioxide gas, or argon.

  The atmosphere temperature (bending treatment temperature) in the bending zone 141 is preferably (Tg-150) ° C. or more and (Tg-30) ° C. or less, where Tg is the glass transition temperature of polyarylate, (Tg-140 It is more preferred that the temperature is not lower than C and not higher than (Tg-50) C.

  The number of times of bending is preferably 100 times or more and less than 1000 times, more preferably 150 times or more and less than 1000 times, and further preferably 200 times or more and less than 1000 times. The number of bendings is counted as one bending operation by one transport roll. When the number of times of bending is large, the heat shrinkage rate of the obtained film can be further reduced.

  The film conveyance speed is, for example, about 10 m to 150 m / min, and preferably 15 m to 100 m / min.

  By performing the bending treatment, the tensile elastic modulus of the obtained film can be made uniform and the heat shrinkage rate can be reduced.

  Then, after providing a slitter as needed and cutting off the both ends of the width direction of a film, you may give a knurling process. The knurling process can be performed by pressing a heated embossing roll. Then, a film can be wound up by making the direction (TD direction) orthogonal to the longitudinal direction (MD direction) of a film into a winding axis | shaft, and can be set as a roll body.

  In addition, you may perform the well-known process for adhesiveness improvement as needed to the surface in which the stress relaxation layer of a polyarylate film is provided. Specifically, treatments such as corona discharge treatment, flame treatment, oxidation treatment, plasma treatment, lamination of a smooth layer and the like can be performed alone or in combination of two or more.

<Stress relaxation layer>
The stress relaxation layer according to this embodiment includes silicon atoms (Si), oxygen atoms (O), and carbon atoms (C). Then, C—C, C—SiO, C—O, C═O, and O—C— at each measurement position, obtained from the depth profile of the C1s spectral region measured by the X-ray photoelectron spectroscopy of the stress relaxation layer. The average value of the ratio (%) of the peak intensity derived from the C—C bond to the peak intensity derived from each bond of O is 1% or more.

  Thereby, the effect that the compressive stress of the polyarylate film which generate | occur | produces when exposed to high temperature is relieve | moderated, and the curl of a polyarylate film can be suppressed is acquired.

  In this embodiment, the stress relaxation layer only needs to be formed on at least one surface of the polyarylate film, and may be formed on both surfaces. In order to effectively relieve the compressive stress of the polyarylate film under a high temperature environment, the stress relaxation layer is preferably disposed so as to be in direct contact with the polyarylate film, but the effect of the present invention can be obtained. As far as it is concerned, another functional layer (for example, an anchor coat layer) may be provided between the polyarylate film and the stress relaxation layer.

  The stress relaxation layer according to this embodiment includes silicon atoms, oxygen atoms, and carbon atoms, and is obtained from the depth profile of the C1s spectral region measured by X-ray photoelectron spectroscopy. The average value of the ratio (%) of the peak intensity derived from the C—C bond to the peak intensity derived from each bond of C—O, C═O and O—C—O is 1% or more. To do. When the average value is less than 1%, the tensile stress of the film is large, and thus curling of the polyarylate film laminate in a high temperature environment (particularly, curling in which the stress relaxation layer side is concavely deformed) may occur. The average value is preferably 2% or more, more preferably 5% or more, further preferably 10% or more, particularly preferably 12% or more, and most preferably 15% or more. On the other hand, the average value is preferably 45% or less, more preferably 40% or less, further preferably 30% or less, particularly preferably 25% or less, and most preferably 20% or less. . When the average value is less than or equal to the above upper limit value, the compressive stress of the stress relaxation layer cancels the tensile stress of the film, so that the curl of the polyarylate film laminate in a high temperature environment (particularly, the stress relaxation layer side has convex deformation). Can be significantly reduced. Therefore, the numerical range of the average value is preferably 1% or more and 45% or less, more preferably 2% or more and 40% or less, still more preferably 5% or more and 30% or less, and particularly preferably 10%. % Or more and 25% or less, and most preferably 15% or more and 20% or less. When the average value is within the above range, even when a stress relaxation layer is formed only on one surface of the polyarylate film, both curl of concave deformation and convex deformation that occur in a high temperature environment. It can be effectively suppressed.

  In addition, it is derived from each bond of C—C, C—SiO, C—O, C═O, and O—C—O at each measurement position obtained from the elemental composition of the stress relaxation layer and the depth profile of the C1s spectral region. The “average value of the ratio (%) of peak intensity derived from C—C bond to the peak intensity” is determined by a measuring method using X-ray photoelectron spectroscopy described in Examples described later. The “average value” here is a value obtained by averaging values measured at intervals of 2 nm by etching in the depth direction by XPS depth profile measurement.

  The lower limit value of the thickness of the stress relaxation layer according to this embodiment is not particularly limited, but is preferably 10 nm or more from the viewpoint of imparting sufficient stress relaxation properties to suppress curling of the polyarylate film in a high temperature environment. More preferably 20 nm or more, still more preferably 30 nm or more, particularly preferably 40 nm or more, and most preferably 50 nm or more. On the other hand, the upper limit of the thickness of the stress relaxation layer is not particularly limited, but from the viewpoint of film transparency, it is preferably 500 nm or less, more preferably 300 nm or less, still more preferably 250 nm or less, particularly preferably. Is 200 nm or less, and most preferably 150 nm or less. That is, the numerical range of the thickness of the stress relaxation layer is preferably 10 to 500 nm, more preferably 20 to 300 nm, still more preferably 30 to 250 nm, and particularly preferably 40 to 200 nm. Preferably it is 50-150 nm.

  Further, the thickness ratio between the polyarylate film and the stress relaxation layer (for one layer) is not particularly limited, but from the viewpoint of effectively suppressing the occurrence of curling in a high temperature environment, the thickness of the polyarylate film The thickness of the stress relaxation layer is preferably 4000: 1 to 50: 1, more preferably 1000: 1 to 100: 1, and still more preferably 600: 1 to 200: 1. .

  The thickness of the stress relaxation layer is measured by the following method.

[Method for measuring thickness of stress relaxation layer]
The thickness of the stress relaxation layer is determined by observing the depth from the outermost surface to the interface with the base material (polyarylate film) in the stacking direction of the stress relaxation layer by cross-sectional observation using a transmission electron microscope (TEM). It can be determined by measuring. In cross-sectional observation with a transmission electron microscope, the thickness is arbitrarily measured at 10 locations, and the average value is taken as the thickness of the stress relaxation layer.

[TEM image of cross section in thickness direction]
As a sample, a TEM observation is performed after producing a thin piece by the following focused ion beam (FIB) processing apparatus. Here, when the sample is continuously irradiated with the electron beam, a contrast difference appears between the portion that is damaged by the electron beam and the portion that is not, so the thickness of the stress relaxation layer can be measured by the contrast difference.

(FIB processing)
Apparatus: SMI2050 manufactured by Seiko Instruments Inc. (SII)
Processed ion: Ga (30 kV)
Sample thickness: 100-200 nm.

(TEM observation)
Apparatus: JEM2000FX manufactured by JEOL Ltd. (acceleration voltage: 200 kV).

<Method for forming stress relaxation layer>
The stress relaxation layer according to the present invention can be formed by plasma enhanced chemical vapor deposition (PECVD (plasma-enhanced chemical vapor deposition) method; hereinafter, also simply referred to as “plasma CVD method”).

  Although it does not specifically limit as a plasma CVD method, The plasma CVD method using the plasma CVD method in the atmospheric pressure or the atmospheric pressure described in the international publication 2006/033233 pamphlet, and the plasma CVD apparatus which has a counter roller electrode is mentioned. It is done. The plasma CVD method may be a Penning discharge plasma type plasma CVD method.

  Among these, it is preferable to use a source gas containing an organic silicon compound and an oxygen gas by a discharge plasma chemical vapor deposition method (a roll-to-roll method) having a discharge space between rollers to which a magnetic field is applied. As described above, by using the discharge plasma chemical vapor deposition method, a stress relaxation layer having an extreme value and having the carbon atom ratio and the C—C bond ratio in each region controlled within a certain range can be obtained. It can be easily manufactured. Thereby, the polyarylate film laminated body with an appropriate stress balance can be produced.

  Here, “having an extreme value” means that the oxygen distribution curve is located at the position where the maximum value of the carbon distribution curve exists in the depth profile of the broad spectrum region measured by X-ray photoelectron spectroscopy of the stress relaxation layer. It means that the minimum value exists and the maximum value of the oxygen distribution curve exists at the position where the minimum value of the carbon distribution curve exists. Existence of an extreme value indicates that the abundance ratio of carbon atoms and oxygen atoms in the stress relaxation layer is not uniform. Becomes a flexible structure, and durability against bending is improved.

  Hereinafter, a method for forming a stress relaxation layer according to the present invention by a discharge plasma chemical vapor deposition method having a discharge space between rollers applied with a magnetic field using a source gas containing an organic silicon compound and oxygen gas will be described. To do.

  When plasma is generated in the plasma CVD method, it is preferable to generate discharge plasma in a space between a plurality of film forming rollers. A pair of film forming rollers is used, and a substrate is provided for each of the pair of film forming rollers. More preferably, a polyarylate film (including a form subjected to a treatment for improving adhesiveness) is arranged and discharged between a pair of film forming rollers to generate plasma.

  In this way, by using a pair of film forming rollers, placing a base material on the pair of film forming rollers, and discharging between the pair of film forming rollers, one film forming roller It is possible to form a film on the surface part of the base material existing on the other film, and simultaneously form the film on the surface part of the base material present on the other film forming roller, so that a thin film can be produced efficiently. In addition, the film formation rate can be doubled compared to a normal plasma CVD method that does not use a roller.

  Further, when discharging between the pair of film forming rollers in this way, it is preferable to reverse the polarities of the pair of film forming rollers alternately. Further, the film forming gas used in such a plasma CVD method preferably contains an organic silicon compound and oxygen, and the oxygen content in the film forming gas is the total amount of the organic silicon compound in the film forming gas. It is preferable that the amount of oxygen be adjusted according to the theoretical oxygen amount required to completely oxidize.

  Hereinafter, the method for forming the stress relaxation layer according to this embodiment will be described in more detail with reference to FIG. FIG. 2 is a schematic diagram showing an example of a plasma CVD apparatus used for forming the stress relaxation layer according to this embodiment.

  A plasma CVD apparatus (plasma CVD film forming apparatus) 200 shown in FIG. 2 includes a feed roller 212, transport rollers 213 to 218, film forming rollers 219 and 220, a gas supply pipe 221, a plasma generating power supply 222, Magnetic field generators 223 and 224 installed inside the film forming rollers 219 and 220, respectively, and a winding roller 225 are provided. Further, in such a plasma CVD apparatus 200, at least the film forming rollers 219 and 220, the gas supply pipe 221, the plasma generating power source 222, and the magnetic field generating apparatuses 223 and 224 are provided in the film forming (vacuum) chamber 228. Is arranged. Further, in such a plasma CVD apparatus 200, the film formation chamber 228 is connected to a vacuum pump (not shown), and the pressure in the film formation chamber 228 can be appropriately adjusted by such a vacuum pump. .

  The feed roller 212 and the transport roller 213 are disposed in the transport system chamber 227, and the take-up roller 225 and the transport roller 218 are disposed in the transport system chamber 229. The transfer system chambers 227 and 229 and the film forming chamber 228 are connected via connecting portions 230 and 231, respectively. For example, a vacuum gate valve may be provided at the connecting portions 230 and 231 to physically separate the film forming chamber 228 and the transfer system chambers 227 and 229 from each other. By using the vacuum gate valve, for example, only the inside of the film forming chamber 228 can be a vacuum system, and the inside of the transfer system chambers 227 and 229 can be in the atmosphere. Further, by physically separating the film formation chamber 228 and the transfer system chambers 227 and 229, it is possible to prevent the transfer system chambers 227 and 229 from being contaminated by particles generated in the film formation chamber 228. .

  In such a manufacturing apparatus, each of the film forming rollers 219 and 220 is provided with a plasma generation power source so that the pair of film forming rollers (film forming rollers 219 and 220) can function as a pair of counter electrodes. 222 is connected. Therefore, in such a plasma CVD apparatus 200, it is possible to discharge into the space between the film formation roller 219 and the film formation roller 220 by supplying power from the plasma generation power source 222, thereby Plasma can be generated in the space between the film formation roller 219 and the film formation roller 220. Note that, in the case where the film formation roller 219 and the film formation roller 220 are also used as electrodes as described above, the material and design thereof may be changed as appropriate so that the film formation roller 219 and the film formation roller 220 can also be used as electrodes.

  In such a plasma CVD apparatus 200, the pair of film forming rollers (film forming rollers 219 and 220) are preferably arranged so that their central axes are substantially parallel on the same plane. Thus, by arranging a pair of film forming rollers (film forming rollers 219 and 220), the film forming rate can be doubled as compared with a normal plasma CVD method in which no roller is used.

  In such a plasma CVD apparatus 200, the polyarylate film 202 is disposed on a pair of film forming rollers (film forming rollers 219 and 220) so that the surfaces of the polyarylate film 202 face each other. By disposing the polyarylate film 202 in this way, a pair of film forming rollers (film forming rollers) is formed when plasma is generated by performing discharge in the facing space between the film forming roller 219 and the film forming roller 220. 219 and 220), the respective surfaces of the polyarylate film 202 existing between them can be formed simultaneously. That is, according to such a plasma CVD apparatus 200, the stress relaxation layer component is deposited on the surface of the polyarylate film 202 on the film forming roller 219 by the plasma CVD method, and further the stress is applied on the film forming roller 220. Since the relaxation layer component can be deposited, the stress relaxation layer 203 can be efficiently formed on the surface of the polyarylate film 202.

  Inside the film forming rollers 219 and 220, magnetic field generators 223 and 224 fixed so as not to rotate even if the film forming rollers 219 and 220 rotate are provided, respectively. As the magnetic field generators 223 and 224, known magnetic field generators can be used as appropriate.

  The magnetic field generators 223 and 224 provided on the film forming rollers 219 and 220, respectively, include a magnetic field generator 223 provided on one film forming roller 219 and a magnetic field generator 224 provided on the other film forming roller 220. It is preferable to arrange the magnetic poles so that the magnetic field lines do not cross between each other and the magnetic field generators 223 and 224 form a substantially closed magnetic circuit. By providing such magnetic field generators 223 and 224, it is possible to promote the formation of a magnetic field in which magnetic lines of force swell in the vicinity of the opposing surface of each film forming roller 219 and 220, and the plasma is converged on the bulging portion. Since it becomes easy, it is excellent at the point which can improve the film-forming efficiency.

  The magnetic field generators 223 and 224 provided on the film forming rollers 219 and 220 respectively have racetrack-shaped magnetic poles that are long in the roller axis direction, and one magnetic field generator 223 and the other magnetic field generator 224 are It is preferable to arrange the magnetic poles so that the opposing magnetic poles have the same polarity. By providing such magnetic field generators 223 and 224, each of the magnetic field generators 223 and 224 has a facing space along the length direction of the roller axis without straddling the magnetic field generator on the roller side where the magnetic lines of force face each other. A racetrack-like magnetic field can be easily formed near the roller surface facing the (discharge region), and the plasma can be converged on the magnetic field. The arylate film 202 is excellent in that the stress relaxation layer 203 that is a vapor deposition film can be efficiently formed.

  The tensions applied to the polyarylate film 202 in each of the film forming rollers 219 and 220 may all be the same, but only the tension in the film forming roller 219 or the film forming roller 220 may be increased. By increasing the tension on the polyarylate film 202 in the film forming rollers 219 and 220, the adhesion between the polyarylate film 202 and the film forming rollers 219 and 220 is improved, heat exchange is performed efficiently, and the film is uniform. There is an advantage that the property is improved and heat wrinkles are suppressed.

  As the film forming rollers 219 and 220, known rollers can be appropriately used. As such film forming rollers 219 and 220, it is preferable to use ones having the same diameter from the viewpoint of forming a thin film more efficiently. The diameters of the film forming rollers 219 and 220 are preferably in the range of 300 to 1000 mmφ, particularly in the range of 300 to 700 mmφ, from the viewpoint of discharge conditions, chamber space, and the like. If the diameter of the film formation roller is 300 mmφ or more, the plasma discharge space is not reduced, so there is no deterioration in productivity, and it is possible to avoid applying the total amount of plasma discharge to the polyarylate film 202 in a short time. It is preferable because damage to the polyarylate film 202 can be reduced. On the other hand, if the diameter of the film forming roller is 1000 mmφ or less, it is preferable because practicality can be maintained in terms of apparatus design including uniformity of plasma discharge space. Each film-forming roller 219 and 220 may be provided with a nip roll, and by providing the nip roll, the adhesion of the polyarylate film 202 to the film-forming rollers 219 and 220 is improved. Accordingly, there is an advantage that heat exchange is efficiently performed between the polyarylate film 202 and the film forming rollers 219 and 220, film uniformity is improved, and heat wrinkles are suppressed.

  As the feed roller 212 and the transport rollers 213 to 218 used in the plasma CVD apparatus 200, known rollers can be used as appropriate. The winding roller 225 is not particularly limited as long as it can wind the polyarylate film laminate 201 in which the stress relaxation layer 203 is formed on the polyarylate film 202, and a known roller is appropriately used. be able to. Further, the feeding roller 212 and the winding roller 225 may be a turret type. The turret may be multiaxial with two or more axes, and may have a structure in which only some of the axes can be opened to the atmosphere.

  Further, as the gas supply pipe 221 and the vacuum pump, those capable of supplying or discharging the source gas or the like at a predetermined speed can be appropriately used.

  The gas supply pipe 221 that is a gas supply means is preferably provided in one of the facing spaces (discharge region, film formation zone) between the film formation roller 219 and the film formation roller 220, and is a vacuum that is a vacuum exhaust means. A pump (not shown) is preferably provided on the other side of the facing space. In this way, by providing the gas supply pipe 221 as the gas supply means and the vacuum pump as the vacuum exhaust means, the film formation gas is efficiently supplied to the facing space between the film formation roller 219 and the film formation roller 220. It is excellent in that the film formation efficiency can be improved.

  In FIG. 2, the gas supply pipe 221 is provided on the center line between the film formation roller 219 and the film formation roller 220, but is not limited to this, for example, the film formation roller 219 and the film formation You may shift | deviate to either one side from the centerline between the rollers 220 (you may shift | deviate from the centerline in the left-right direction). By shifting the gas supply pipe 221 from the center line between the film formation roller 219 and the film formation roller 220, the gas supply pipe 221 is closer to one film formation roller and farther from the other film formation roller. Thus, since the film composition formed on the film forming roller 219 and the film composition formed on the film forming roller 220 can be different from each other, the means used when changing the film quality is used. It is effective as In addition, the gas supply pipe 221 may be appropriately separated from or closer to the film forming roller on the center line (the arrangement position may be moved on the center line in the vertical direction). By moving the gas supply tube 221 away from the discharge space on the central axis of the film forming roller, there is an advantage that particles can be prevented from adhering to the gas supply tube 221. Further, there is an advantage that the film forming rate can be improved by bringing the gas supply tube 221 closer to the discharge space on the central axis of the film forming roller.

  In FIG. 2, there is one gas supply pipe 221, but there may be a plurality of gas supply pipes 221, and different supply gases may be discharged from each nozzle.

  Further, as the plasma generating power source 222, a known power source of a plasma generating apparatus can be used as appropriate. Such a plasma generating power supply 222 supplies power to the film forming roller 219 and the film forming roller 220 connected thereto, and makes it possible to use these as counter electrodes for discharge. As such a plasma generating power supply 222, since it is possible to perform plasma CVD more efficiently, a power supply capable of alternately reversing the polarity of a pair of film forming rollers (AC power supply or the like) is used. It is preferable to use it.

  Moreover, as such a plasma generation power source 222, since it becomes possible to perform plasma CVD more efficiently, it is preferable to set the applied power within the range of 100 W to 20 kW, and within the range of 100 W to 10 kW. It is more preferable that the AC frequency be in the range of 50 Hz to 13.56 MHz, and more preferably in the range of 50 Hz to 500 kHz.

  Further, from the viewpoint of stabilizing the plasma process, a high frequency power source in which both the high frequency current wave and the voltage wave are sine waves may be used.

  In FIG. 2, power is supplied to both film forming rollers 219 and 220 by one plasma generating power source 222 (both film forming roller power supply), but the present invention is not limited to such a form. The film roller may be supplied with power (one-side film formation roller power supply) and the other film formation roller may be grounded.

  Moreover, as a power feeding method to the film forming roller, roller one-end power feeding from only one of the roller ends may be used, or roller both-end power feeding from both ends of the roller may be used. In the case of supplying a high frequency band, it is possible to supply both ends of the roller because uniform supply is possible.

  Further, as a feeding method, two-frequency feeding may be performed in which different frequencies are applied, and one film-forming roller and the other film-forming roller may be applied even when two different frequencies are applied to one film-forming roller. A different frequency may be applied. By such two-frequency power feeding, the plasma density can be increased and the film formation rate can be improved.

  Although not shown in FIG. 2, the plasma emission intensity in the discharge space is monitored from the outside, and if the desired emission intensity is not obtained, the distance between the magnetic fields (distance between the opposing rollers), the magnetic field intensity, and the power applied to the power source In addition, a feedback circuit that adjusts the power supply frequency, the amount of supplied gas, and the like to obtain a desired plasma emission intensity may be provided. By having such a feedback circuit, film formation / production can be stabilized.

  Using such a plasma CVD apparatus 200 shown in FIG. 2, a stress relaxation layer containing silicon atoms, oxygen atoms, and carbon atoms and having a C—C bond ratio within a predetermined range can be formed. At this time, the atomic ratio of the carbon atom content and the C—C bond ratio in the stress relaxation layer can be controlled by adjusting the ratio of the raw materials used, power, pressure, and the like.

  The pressure (degree of vacuum) in the vacuum chamber can be appropriately adjusted according to the type of the raw material gas and the like, and is preferably about 0.5 to 50 Pa, and preferably within the range of 0.5 to 10 Pa. More preferred.

  In such a plasma CVD method, an electrode drum (in this embodiment, the film forming roller 219) connected to the plasma generation power source 222 to discharge between the film forming roller 219 and the film forming roller 220. And 220), the electric power to be applied can be adjusted as appropriate according to the type of the source gas, the pressure in the vacuum chamber, etc. It is preferable to be within the range. If the applied power is 0.1 kW (100 W) or more, generation of particles can be sufficiently suppressed. On the other hand, if the applied power is 10 kW or less, the amount of heat generated during film formation can be suppressed, and an increase in the temperature of the substrate surface during film formation can be suppressed. Therefore, it is excellent in that wrinkles can be prevented from occurring during film formation without causing the substrate to lose heat.

  The conveyance speed (line speed) of the polyarylate film 202 can be appropriately adjusted according to the type of source gas, the pressure in the vacuum chamber, etc., but is preferably in the range of 0.25 to 100 m / min. More preferably, it is within the range of 0.5 to 100 m / min.

  Adjustment of the composition ratio of each of silicon atoms, oxygen atoms, and carbon atoms in the stress relaxation layer, and the ratio of each bond of C—C, C—SiO, C—O, C═O, and O—C—O For example, the following methods (1) to (4) can be adopted to control within a predetermined range.

(1) Control by plasma CVD source gas (organosilicon compound) As a source material for plasma CVD source gas, an organosilicon compound containing silicon atoms, oxygen atoms, carbon atoms and hydrogen atoms in a specific composition ratio is appropriately used. Can be controlled.

  As a raw material for plasma CVD, an organosilicon compound having a low Si—C bond ratio in the molecule is preferably used. The number (ratio) of Si—C bonds in these organosilicon compounds is preferably 2 or less, more preferably 1 or 0, per 1 Si atom.

  Specifically, rather than disiloxanes such as hexamethyldisiloxane and tetramethyldisiloxane, octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane (specifically 2,4,6,8-tetramethylcyclohexane). A cyclic siloxane such as tetrasiloxane) or an alkoxysilane containing one Si per molecule such as tetramethoxysilane or methyltrimethoxysilane is preferably used. These compounds can be used individually by 1 type or in combination of 2 or more types.

(2) Control by supply amount of oxygen gas as reaction gas It is possible to control by increasing / decreasing the supply amount of oxygen gas supplied as a reaction gas during film formation by plasma CVD.

  The supply amount of oxygen gas is set to such a supply amount that does not cause excessive carbon to remain in the stress relaxation layer while suppressing the supply amount to such an extent that the source gas is not completely oxidized.

(3) Control of addition amount of inert gas It controls by supplying inert gas, such as nitrogen, argon, and helium, and adjusting the supply amount of this inert gas during film-forming. Thereby, the plasma at the time of forming a stress relaxation layer can be stabilized and an oxidation reaction can be adjusted.

(4) Control of distance between electrodes for plasma discharge It is also possible to control by continuously changing the distance between electrodes for plasma discharge.

  In the case of using a device in which the above-described pair of roll electrodes are opposed to each other, the plasma discharge space is changed by changing the distance between the electrodes. As a result, the film forming conditions are changed, so that the composition in the stress relaxation layer can be continuously changed.

  Next, a film forming gas for forming the stress relaxation layer will be described.

  As the film forming gas, a reactive gas may be used in addition to the source gas. As such a reactive gas, a gas that reacts with the raw material gas to become an inorganic compound such as an oxide can be appropriately selected and used. Since the stress relaxation layer 203 according to this embodiment includes oxygen atoms, for example, oxygen gas or ozone gas can be used as the reactive gas, and oxygen gas is preferably used from the viewpoint of simplicity. In addition, a reactive gas for forming a nitride may be used. For example, nitrogen gas or ammonia can be used. These reaction gases can be used alone or in combination of two or more. For example, when forming an oxynitride, the reaction gas for forming an oxide and a nitride are formed. Can be used in combination with the reaction gas for

  In order to supply the source gas into the film formation chamber 228 as the film formation gas, a carrier gas may be used as necessary. Further, a discharge gas may be used as a film forming gas, if necessary, in order to generate discharge plasma. As such carrier gas and discharge gas, known ones can be used as appropriate, and for example, rare gases such as helium, argon, neon, xenon, hydrogen, and nitrogen can be used.

  As described above, when the film forming gas contains the source gas and the reactive gas, the ratio of the source gas and the reactive gas is the theoretically necessary reactive gas for causing the raw material gas and the reactive gas to completely oxidize. It is preferable to adjust to 50% or more and 300% or less with respect to the ratio of the amount of 100%. By adjusting the ratio of the reaction gas within this range, the carbon atoms inside the formed stress relaxation layer can be adjusted to a preferable composition distribution, and excellent stress relaxation properties and bending resistance can be obtained.

  When the ratio is lower than the above ratio, the ratio of carbon atoms in the stress relaxation layer becomes high, and it becomes difficult to maintain sufficient stress relaxation properties. On the other hand, when the ratio is higher than the above ratio, the ratio of C—C bonds in the stress relaxation layer decreases as the oxidation proceeds.

  A plasma CVD apparatus 200 shown in FIG. 2 is used to generate a discharge between a pair of film forming rollers (film forming rollers 219 and 220) while supplying a film forming gas (such as a source gas) into the film forming chamber 228. As a result, the deposition gas (raw material gas or the like) is decomposed by the plasma, and the first time on the surface of the polyarylate film 202 on the deposition roller 219 and on the surface of the polyarylate film 202 on the deposition roller 220. The film formation layer is formed by a plasma CVD method. At this time, a racetrack-shaped magnetic field is formed in the vicinity of the roller surface facing the facing space (discharge region) along the length direction of the roller axes of the film forming rollers 219 and 220, and the plasma is converged on the magnetic field. By repeating this process with the second deposition layer and the third deposition layer in which one or more of the above conditions (1) to (4) are changed, the composition of each constituent atom is increased in thickness. It will change continuously in the direction.

  Specifically, in the silicon distribution curve, oxygen distribution curve and carbon distribution curve, when the polyarylate film 202 passes through the point A of the film forming roller 19 and the point B of the film forming roller 20, the maximum value of the carbon distribution curve. And the minimum value of the oxygen distribution curve. In contrast, when the polyarylate film 202 passes through points C1 and C2 of the film forming roller 19 and points C3 and C4 of the film forming roller 20, the minimum value of the carbon distribution curve and the maximum value of the oxygen distribution curve Is formed.

  As described above, the stress relaxation layer forming method according to one embodiment of the present invention is formed by the plasma CVD method using the plasma CVD apparatus (roll-to-roll method) having the counter roller electrode illustrated in FIG. It is characterized by. According to this method, the stress relaxation layer having a predetermined C—C bond ratio can be easily mass-produced at a low cost.

<Other layers>
The polyarylate film laminate of this embodiment has other functional layers such as an anchor coat layer and a hard coat layer in addition to the above-described polyarylate film and functional layer within the range where the effects of the present invention can be obtained. May be.

[Anchor coat layer]
An anchor coat layer may be formed on the surface of the polyarylate film on the side where the functional layer is formed for the purpose of improving the adhesion between the film and the functional layer.

  Examples of the anchor coating agent used for the anchor coat layer include polyester resins, isocyanate resins, urethane resins, acrylic resins, ethylene vinyl alcohol resins, vinyl modified resins, epoxy resins, modified styrene resins, modified silicone resins, and alkyl titanates. It is done. These can be used alone or in combination of two or more. Moreover, a conventionally well-known additive can also be added to these anchor coating agents.

The formation method of the anchor coat layer is not particularly limited, and the above-described anchor coat agent is coated on the polyarylate film surface using a known method such as roll coat, gravure coat, knife coat, dip coat, spray coat, It can be formed by drying and removing a solvent, a diluent and the like. The application amount of the anchor coating agent is preferably about 0.1 to 5.0 g / m ² (dry state).

  The anchor coat layer can also be formed by a vapor phase method such as physical vapor deposition or chemical vapor deposition. For example, as described in JP-A-2008-142941, an inorganic film mainly composed of silicon oxide can be formed for the purpose of improving adhesion and the like. Alternatively, by forming an anchor coat layer as described in Japanese Patent Application Laid-Open No. 2004-314626, when a stress relaxation layer is formed thereon by a vapor phase method, from the base material (polyarylate film) side The composition of the polyarylate film can be controlled by blocking the generated gas to some extent.

  The thickness of the anchor coat layer is not particularly limited, but is preferably about 0.5 to 10 μm.

[Hard coat layer]
A hard coat layer may be provided on the surface (one side or both sides) of the polyarylate film. Examples of the material for the hard coat layer include thermosetting resins and active energy ray curable resins. Among these, active energy ray-curable resins are preferable because the hard coat layer can be easily formed. Such curable resins may be used alone or in combination of two or more.

  The active energy ray-curable resin refers to a resin that is cured through a crosslinking reaction or the like by irradiation with active energy rays such as ultraviolet rays and electron beams. As the active energy ray curable resin, those containing a monomer having an ethylenically unsaturated double bond are preferably used. By curing such an active energy ray curable resin by irradiating active energy rays such as ultraviolet rays and electron beams, a layer containing a cured product of the active energy ray curable resin, that is, a hard coat layer is formed. The Typical examples of the active energy ray curable resin include an ultraviolet curable resin and an electron beam curable resin, and among them, an ultraviolet curable resin that is cured by ultraviolet irradiation is preferable. Moreover, you may use the commercially available base material (polyarylate film) in which the hard-coat layer is formed previously. As the ultraviolet curable resin, for example, Z-731L (manufactured by Aika Industry Co., Ltd.), Opstar (registered trademark) Z7527 (manufactured by JSR Corporation), or the like is preferably used.

  The method for forming the hard coat layer is not particularly limited, but is preferably formed by a wet coating method such as a spin coating method, a spray method, a blade coating method, or a dip method, or a dry coating method such as an evaporation method.

  The thickness of the hard coat layer is not particularly limited, but is preferably about 0.5 to 10 μm.

<Application>
Like the conventional polyarylate film, the polyarylate film laminate of the present invention has high transparency and heat resistance, and has a characteristic that curling hardly occurs even in a high temperature environment. Therefore, the polyarylate film of the present invention is used in a wide range of applications that require these characteristics; for example, a transparent substrate or transparent electrode substrate (glass) in flexible panel displays (organic EL displays, liquid crystal displays, electronic paper, etc.), solar cells, etc. Substrate instead of substrate); insulating base material and cover film of flexible printed circuit board (FPC) for applications requiring transparency; used for transparent conductive film used for touch panel and the like.

<Manufacture of polyarylate film laminate>
[Example 1]
(Synthesis of polyarylate)
After adding 2514 parts by mass of water to a reaction vessel equipped with a stirrer, 22.7 parts by mass of sodium hydroxide and 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene as an aromatic dialcohol component (BCF) 35.6 parts by mass, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA) 18.5 parts by mass, p-tert-butylphenol (PTBP) 0. 049 parts by mass was dissolved, and 0.34 parts by mass of tributylbenzylammonium chloride was added as a polymerization catalyst and stirred.

  On the other hand, 26.8 parts by mass of an equimolar mixture of terephthalic acid chloride and isophthalic acid chloride as an aromatic dicarboxylic acid component was weighed and dissolved in 945 parts by mass of methylene chloride. This methylene chloride solution was added to the alkaline aqueous solution containing the aromatic dialcohol component prepared above with stirring to initiate polymerization. The polymerization reaction temperature was adjusted to be 15 ° C. or higher and 20 ° C. or lower. The polymerization was carried out for 2 hours, and then acetic acid was added to the system to stop the polymerization reaction, and the organic phase and the aqueous phase were separated.

  The obtained organic phase was washed with ion exchange water twice as much as the organic phase for each washing, and then the operation of separating the organic phase and the aqueous phase was repeated. The washing was terminated when the electric conductivity of the washing water became less than 50 μS / cm. The organic phase after washing was put into a hot water tank equipped with a homomixer at 50 ° C., and methylene chloride was evaporated to obtain a powdery polymer. Furthermore, dehydration and drying were performed to obtain polyarylate. The obtained polyarylate had a glass transition temperature (Tg) of 270 ° C.

(Manufacture of polyarylate film)
(1) Preparation of polymer solution 14 parts by mass of polyarylate and 100 parts by mass of methylene chloride (boiling point: 40.4 ° C) were put in a closed container, gradually heated to 35 ° C while stirring, and completely dissolved. I let you. The obtained solution was Azumi Filter Paper No. Filtration using 244 gave a polymer solution.

(2) Film formation The obtained polymer solution was uniformly cast on a stainless belt of a belt casting apparatus. A stainless steel belt having a length of 20 m was used. The surface temperature of the stainless steel belt is 35 ° C. and 35 ° C. wind is applied to the cast film to evaporate the solvent until the residual solvent amount is 38% by mass, and then the film is peeled off from the stainless steel belt. Obtained.

(3) Stretching After stretching the obtained film-like material 1.2 times at 170 ° C. in the MD direction using the peripheral speed difference between rolls, 1.2 times at 230 ° C. in the TD direction with a tenter. Drawing (sequential biaxial drawing) was performed.

(4) Bending The film obtained after stretching was subjected to bending treatment at 140 ° C. 200 times while being rolled in a bending apparatus. The roll diameter was 108 mm, the distance between the centers of two rolls adjacent in the film transport direction was 324 mm, and the film transport speed was 5 m / min.

  The obtained film was dried for 30 minutes while being transported in a drying apparatus at 125 ° C. by a number of rolls, and then subjected to knurling with a width of 15 mm and a height of 10 μm at both ends in the width direction of the film to obtain a film thickness of 40 μm. Film was obtained.

(Formation of stress relaxation layer)
The polyarylate film was set in a roll-to-roll type plasma CVD film forming apparatus and evacuated. Thereafter, a stress relaxation layer was formed to 100 nm on one surface of the film to prepare a polyarylate film laminate 1 (sample 1). At this time, 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS) 50 sccm (Standard Cubic Centimeter per Minute) and oxygen gas 1000 sccm are supplied into the apparatus as the plasma CVD source, and an apparatus for film formation is provided. The internal pressure was set to 1 Pa. A 100 kHz high frequency power source was used as the plasma generating power source. The film conveyance speed was 40 m / min.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 5%.

[Example 2]
In the above (formation of stress relaxation layer), the polyarylate film laminate 2 was prepared in the same manner as in Example 1 except that the plasma CVD raw material was TMCTS 50 sccm, oxygen gas 1000 sccm, and the internal pressure of the apparatus during film formation was 1.5 Pa. (Sample 2) was produced.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 5%.

[Example 3]
A polyarylate film laminate 3 (sample 3) was produced in the same manner as in Example 1 except that the plasma CVD raw material was changed to TMCTS 100 sccm and oxygen gas 100 sccm in the above (formation of stress relaxation layer).

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Example 4]
A polyarylate film laminate 4 (sample 4) was produced in the same manner as in Example 1 except that the plasma CVD raw material was changed to TMCTS 200 sccm and oxygen gas 200 sccm in the above (formation of stress relaxation layer).

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Example 5]
In the above (formation of stress relaxation layer), the polyarylate film laminate 5 (sample) was prepared in the same manner as in Example 1 except that the plasma CVD raw material was TMCTS 200 sccm, oxygen gas 200 sccm, and the pressure in the apparatus during film formation was 3 Pa. 5) was produced.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 15%.

[Example 6]
In the above (manufacturing the polyarylate film), the polyarylate film was laminated in the same manner as in Example 3 except that the stretching conditions were 1.4 times at 170 ° C. in the MD direction and 1.8 times at 230 ° C. in the TD direction. A body 6 (sample 6) was produced.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Example 7]
In the above (manufacturing the polyarylate film), the surface temperature of the stainless steel belt is set to 34 ° C., the air temperature to the casting film is set to 33 ° C., and the stretching conditions are 1.2 times at 165 ° C. in the MD direction and in the TD direction. It was 1.2 times at 225 ° C. and no bending treatment was performed. Other than that was carried out similarly to Example 3, and produced the polyarylate film laminated body 6 (sample 7).

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Example 8]
In the above (manufacturing the polyarylate film), the polyarylate film laminate 8 (in the same manner as in Example 3 except that the surface temperature of the stainless steel belt was 30 ° C. and the air temperature to the casting film was 30 ° C. Sample 8) was prepared.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Example 9]
In the above (formation of stress relaxation layer), the polyarylate film laminate 9 (sample) was made in the same manner as in Example 1 except that the plasma CVD raw material was TMCTS 300 sccm, oxygen gas 300 sccm, and the internal pressure of the apparatus during film formation was 3 Pa. 9) was produced.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 15%.

[Example 10]
In the above (manufacture of polyarylate film), a polyarylate film laminate 10 (sample 10) was produced in the same manner as in Example 3 except that both the MD direction and the TD direction were not stretched.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Comparative Example 1]
A polyarylate film laminate 11 (sample 11) was produced in the same manner as in Example 1 except that the plasma CVD raw material was changed to TMCTS 50 sccm and oxygen gas 2000 sccm in the above (formation of stress relaxation layer).

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 3%.

[Comparative Example 2]
In the above (production of polyarylate film), the polyarylate film was laminated in the same manner as in Example 3 except that the stretching conditions were 1.2 times at 170 ° C. in the MD direction and 1.8 times at 230 ° C. in the TD direction. A body 12 (sample 12) was produced.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Comparative Example 3]
In the above (manufacturing the polyarylate film), the polyarylate film was laminated in the same manner as in Example 3 except that the stretching conditions were 1.8 times at 170 ° C. in the MD direction and 1.9 times at 220 ° C. in the TD direction. A body 13 (sample 13) was produced.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

[Comparative Example 4]
In the above (manufacturing the polyarylate film), the solvent of the polymer solution was changed to dimethylacetamide (boiling point 165 ° C.), the drying temperature was changed to belt temperature 120 ° C. and wind temperature 125 ° C., and the stretching condition was 1 at 160 ° C. in the MD direction. A polyarylate film laminate 14 (sample 14) was prepared in the same manner as in Example 3 except that the ratio was 1.2 times and 1.2 times at 230 ° C. in the TD direction.

  In addition, the carbon composition ratio calculated | required from the depth profile measured by the X ray photoelectron spectroscopy (XPS) of a stress relaxation layer was 12%.

<Measurement of tensile modulus of polyarylate film>
First, “direction A in which the refractive index is maximum in the film plane” was confirmed as a slow axis using an automatic birefringence meter KOBRA-21ADH or KOBRA-WR (Oji Scientific Instruments). As a result, it was confirmed that the direction A was the TD direction and the direction B was the MD direction.

  Next, for each of the direction A (TD direction) and the direction B (MD direction), the tensile modulus was measured by the following method in accordance with JIS K7127 (1999).

  1) A polyarylate film was cut into a size of 100 mm (MD direction) × 10 mm (TD direction) to obtain a test piece. This test piece was pulled in the longitudinal direction (MD direction) of the test piece using Tensilon RTC-1225A manufactured by Orientec Co., Ltd., and the tensile modulus in the MD direction was measured. The measurement was performed at 23 ° C. and 55% RH.

  2) In the same manner as in 1) above, the polyarylate film was cut into a size of 100 mm (TD direction) × 10 mm (MD direction) to obtain a test piece. The test piece was pulled in the longitudinal direction (TD direction) in the same manner as in 1) above, and the tensile elastic modulus in the TD direction was measured.

  3) The average value of the tensile modulus of elasticity in the MD direction and the TD direction obtained in 1) and 2) and the absolute value of the difference were calculated.

<Measurement of C-C bond ratio of stress relaxation layer>
(X-ray photoelectron spectroscopy)
Silicon distribution curve (distance (L) from the outermost surface of the stress relaxation layer in the thickness direction of the stress relaxation layer and the ratio of the number of silicon atoms to the total number of silicon atoms, oxygen atoms and carbon atoms (100 atm%) (silicon Curve showing the relationship with the atomic ratio), oxygen distribution curve (the distance (L), and the ratio of oxygen atoms to the total number of silicon atoms, oxygen atoms and carbon atoms (100 atm%) (oxygen atom ratio)) And the carbon distribution curve (the distance (L) and the ratio of the number of carbon atoms to the total number of atoms (100 atm%) of silicon atoms, oxygen atoms and carbon atoms (carbon atom ratio)). Curve) using both X-ray photoelectron spectroscopy (XPS) measurement and rare gas ion sputtering such as argon More performs sequential surface composition analysis while exposing the internal samples, were prepared by the so-called XPS depth profile measurement.

(Measurement of XPS depth profile)
The XPS depth profile was measured under the following conditions. This obtained the carbon distribution curve, the silicon distribution curve, and the oxygen distribution curve with respect to the distance (L) from the outermost surface of the stress relaxation layer in the thickness direction of the stress relaxation layer.

Etching ion species: Argon (Ar ⁺ )
Etching rate (SiO ₂ thermal oxide equivalent value): 0.05 nm / sec Etching interval (SiO ₂ equivalent value): 2 nm
X-ray photoelectron spectrometer: Model “VG Theta Probe”, manufactured by Thermo Fisher Scientific
Irradiation X-ray: Single crystal spectroscopy AlKα
X-ray spot and size: 800 μm × 400 μm oval.

  The distribution curve obtained by such XPS depth profile measurement was created with the vertical axis as the atomic ratio (atm%) of each element and the horizontal axis as the etching time (sputtering time).

  The atomic ratio (atm%) in each region was an average value of values measured at 2 nm intervals by etching in the depth direction by XPS depth profile measurement.

  As described above, a silicon distribution curve, an oxygen distribution curve, and a carbon distribution curve were obtained by performing a wide scan spectrum analysis for measuring the entire stress relaxation layer.

(Analysis of bonding state of carbon atoms)
Regarding carbon atoms, the carbon bonding state was analyzed by a high resolution spectrum (narrow scan analysis) of C1s. Specifically, regarding the carbon (C) bond, based on the waveform analysis of C1s, (1) C—C, (2) C—SiO, (3) C—O, (4) C═O, (5 ) O—C—O, divided into five bond groups, and the intensity ratio of each peak was determined. In addition, the ratio (%) of the peak intensity was an average value of values measured at 2 nm intervals by etching in the depth direction by XPS depth profile measurement. And the average value of the ratio (%) of the peak intensity derived from (1) CC bond with respect to the sum total of the peak intensity ratios of (1) to (5) was calculated.

  The analysis of the peak intensity was performed using data analysis software PeakFit (manufactured by SYSSTAT Software Inc.).

<Measurement of film curl>
After the film cut to 100 mm × 100 mm was heated at 200 ° C. for 100 hours, the curl heights at four corners were measured, and the average value of the four values was calculated. The obtained value was taken as the value of film curl. In addition, the curl which becomes the concave deformation on the stress relaxation layer side is defined as + curl, and the curl which forms the convex deformation is defined as -curl.

  The results are shown in Table 1 below.

  From the results of Table 1 above, the polyarylate film laminates of Examples 1 to 10 according to the present invention have significantly reduced film curl (concave or convex deformation) caused by exposure to high temperatures. Indicated.

  In particular, from the results of Examples 1 to 5 and Example 10, when the ratio of the C—C bond of the stress relaxation layer is 1%, 2%, and 15%, + curl (curl in which the stress relaxation layer side is concavely deformed) On the other hand, when the proportion of C—C bonds is 20%, 40%, or 45%, −curl (curl in which the stress relaxation layer side is convexly deformed) occurred. And when it was in the range of the ratio of C—C bond 15 to 20%, it was found that the curl suppressing effect was the greatest.

  On the other hand, Comparative Example 1 with a C—C bond ratio of 0.5%, which is outside the scope of the present invention, Comparative Example 3 with an average tensile modulus of 4.6 GPa, and an average value of tensile modulus is In Comparative Example 4 which is 2.1 GPa and in Comparative Example 2 where the absolute value of the difference in tensile elastic modulus is 1.7 GPa, significant curling occurred.

100 Film production equipment,
120 casting device,
121 dice,
123 metal support,
123A roll,
125 peeling roll,
130 stretching device,
131 roll stretching device,
133 tenter stretching device,
140 bending equipment,
141 Bending zone,
143 Inlet,
145 exhaust vent,
147A, 147B transport roll,
200 plasma CVD equipment,
201 polyarylate film laminate,
202 polyarylate film,
203 stress relaxation layer,
212 feed roller,
213, 214, 215, 216, 217, 218 transport rollers,
219, 220 Deposition roller,
221 gas supply pipe,
222 Power source for plasma generation,
223, 224 magnetic field generator,
225 take-up roller,
227, 229 transfer system chamber,
228 deposition chamber,
230, 231 connecting portion.

Claims (4)

A stress relaxation layer containing silicon atoms, oxygen atoms and carbon atoms on at least one surface of the polyarylate film;
The polyarylate film has an average value of 2.5 GPa between the tensile elastic modulus at 23 ° C. in the direction A where the refractive index is maximum in the film plane and the tensile elastic modulus at 23 ° C. in the direction B perpendicular to the direction A. The absolute value of the difference between the tensile elastic modulus in the direction A and the tensile elastic modulus in the direction B is 1.5 GPa or less.
C—C, C—SiO, C—O, C═O and O—C—O at each measurement position determined from the depth profile of the C1s spectral region measured by X-ray photoelectron spectroscopy of the stress relaxation layer. The polyarylate film laminated body whose average value of the ratio (%) of the peak intensity derived from the C—C bond to the peak intensity derived from each bond is 1% or more.   The polyarylate film laminate according to claim 1, wherein the average value is 1% or more and 45% or less.   The polyarylate film laminate according to claim 1, wherein the average value is 2% or more and 20% or less.   The polyarylate film laminate according to any one of claims 1 to 3, wherein the polyarylate film is a biaxially stretched film.