JP7331362B2 - film - Google Patents

Description

The present invention relates to manufacturing process films.

Thermoplastic resin films are widely used in optical applications, packaging applications, industrial material applications, and the like, depending on their various properties. In industrial material applications, thermoplastic resin films are used as process substrates for manufacturing semiconductor thin films and circuit components. , Patent Document 1) and a release film used in forming a circuit member (for example, Patent Document 2) have been proposed.

In the case of the film as seen in Patent Document 1, the heat-expandable microspheres are expanded by heating to change the film surface shape, thereby improving the pick-up property of the semiconductor. When using a coating material that is more flexible than a semiconductor as a process substrate, the surface shape change is transferred to the coating material, resulting in insufficient smoothness of the coating material, or the desired peeling due to the anchor effect. It was sometimes difficult to obtain In addition, since the pressure-sensitive adhesive layer is arranged on the outermost surface of the film, the film itself may be easily damaged or foreign matter may easily adhere to it.

In the case of the film as seen in Patent Document 2, it has a matte surface design, and when used as a process base material, the smoothness of the resulting coating material may be insufficient, and depending on the coating material, it may not be desired. In some cases, it was difficult to obtain the peelability of

JP 2012-033636 A JP 2016-043594 A

In the present invention, the above drawbacks are eliminated, and when used as a process substrate for applying a functional material to obtain a thin film of a functional material layer (functional film), the coating properties, peelability after processing, An object of the present invention is to provide a film capable of improving the properties and quality of a functional film.

A first film of the present invention for solving the above problems has the following configuration.
(1) A film having a polymer A layer on at least one side, wherein the main component of the polymer A layer is a polyester-based resin, and the maximum height of the polymer A layer determined by AFM is Rm1 (nm), 180 ° C. 5 A film which satisfies the following formula (I), where Rm2 (nm) is the maximum height of the polymer A layer obtained by AFM after heat treatment for a minute.
Rm2−Rm1>0 nm (I)
(2) The film according to (1), which satisfies the following formula (II).
1 nm≦(Rm2−Rm1)≦2.0×10 ⁴ nm (II)
(3) Satisfying the following formula (III), where Ra2 (nm) is the arithmetic mean roughness of the polymer A layer obtained by AFM after heat treatment at 180° C. for 5 minutes, (1) or (2) The film described in .
6≦(Rm2/Ra2)≦15 (III)
(4) The film according to any one of (1) to (3), which satisfies the following formula (IV).
(Rm2/Ra2)-(Rm1/Ra1)>0 (IV)
(5) The film according to claim 1, wherein the polymer A layer contains at least one polymer different from the polyester resin.
(6) The film according to any one of (1) to (5), wherein the polymer A layer has a glossiness (60°) of 30 or more after heat treatment at 180°C for 5 minutes.
(7) The film according to any one of (1) to (6), wherein the indentation modulus of the polymer A layer is 800 N/mm ² or more and 6,000 N/mm ² or less.
(8) The film according to any one of (1) to (7), which has a tear propagation resistance of 4.0 N/mm or more and 12.0 N/mm or less in the main orientation axis direction and in the direction perpendicular to the main orientation axis. .
(9) The film according to any one of (1) to (8), which is used for manufacturing process applications.

A second film of the present invention for solving the above problems has the following configuration. That is, in a film having a polymer A layer on at least one side, the surface free energy of the polymer A layer is SE1 (mN/m), and the surface free energy of the polymer A layer after heat treatment at 180 ° C. for 5 minutes is SE2 (mN / m), the film is characterized by satisfying the following formula (I)
SE1-SE2>0mN/m (a)

The first and second films of the present invention can improve adhesion before heating and peelability after heating. When used as a process base material, it has the effect of improving the properties and quality of the functional film.

The film of the present invention will be described in detail below.
[First film]
The first film of the present invention is a film having a polymer A layer on at least one side, and the maximum height of the polymer A layer obtained by AFM is Rm1 (nm), and after heat treatment at 180 ° C. for 5 minutes, the AFM It is important to satisfy the following formula (I), where Rm2 (nm) is the maximum height of the polymer A layer obtained in .
Rm2−Rm1>0 nm (I)
Here, Rm1 (nm) is a value obtained as follows. In AFM (atomic force microscope) such as "NanoScope V Dimension Icon" made by Bruker AXS, a silicon cantilever is applied as a probe and the surface shape of the film is measured in tapping mode. Analysis, etc.) was used to calculate the maximum height under the condition of a cutoff of 3 nm. Such measurements are repeated 5 times, and the average value of the 5 measurements is obtained. In addition, the measurement direction (scanning direction of the probe) is an arbitrary direction and a direction orthogonal to the arbitrary direction, and the average value of the maximum height in each direction (i.e., An average value of a total of 10 measurements (5 measurements in an arbitrary direction and 5 measurements in a direction perpendicular to the arbitrary direction) is adopted as Rm1 (nm).

For Rm2 (nm), the maximum height of a film heat-treated at 180° C. for 5 minutes is calculated five times in the same manner as for Rm1 (nm), and the average value of the five measurements is obtained. In addition, the measurement direction (scanning direction of the probe) is an arbitrary direction and a direction orthogonal to the arbitrary direction, and the average value of the maximum height in each direction (i.e., An average value of a total of 10 measurements (5 measurements in an arbitrary direction and 5 measurements in a direction perpendicular to the arbitrary direction) is adopted as Rm2 (nm).

In the present invention, the heat treatment at 180° C. for 5 minutes is a treatment simulating the heating of the film to dry the functional film and improve its functionality when the film is used as a process substrate for the functional film. , for example, refers to a process in which the film is conveyed to a hot air circulation type conveyor oven set at 180° C. for 5 minutes. When transporting the film, the film is sandwiched between two metal frames, and then the metal frames are fixed with a metal clip so that the film does not come into direct contact with the conveyor.

In the present invention, the formula (I) indicates that the maximum height of the polymer A layer determined by AFM increases after heat treatment at 180° C. for 5 minutes. Note that the maximum heights such as Rm1 (nm) and Rm2 (nm) obtained under these conditions have a very narrow measurement range, unlike measurement with a general contact-type three-dimensional roughness meter. The value is less susceptible to the effects of sand matte film, embossed film, and unevenness of the matte film due to kneaded particles. By increasing the maximum height in a minute range obtained by AFM after heating, for example, when the film of the present invention has a structure in which it is laminated with a functional film, the smoothness of the functional film is greatly changed. It is possible to form a minute space at the interface between the film and the functional film without removing the film and reduce the adhesion to the functional film. That is, the film of the present invention increases the maximum height in a minute range required by AFM after heating, so that the adhesion to the functional film before heating and the peelability from the functional film after heating It is found that it can be compatible with

As a method for making Rm1 (nm) and Rm2 (nm) within the range of formula (I), the polymer A layer is formed by combining two or more types of polymers, and after stretching the polymer A layer, the polymer A A method of deforming only the low melting point polymer among the polymers contained in the layer by heating at 180 ° C. for 5 minutes to form strain on the surface of the polymer A layer. Microcrystals are formed in the polymer A layer by plasma treatment or the like, and by heating at 180 ° C. for 5 minutes, only the amorphous part around the microcrystals is thermally moved to form strain on the layer A surface. voids are formed in advance, and the polymer around the voids is softened by heating at 180° C. for 5 minutes to change the shape of the voids and create strain on the surface of the polymer A layer. In the case of using a method of stretching the polymer A layer and then deforming only the polymer with a low melting point among the polymers contained in the polymer A layer by heating at 180° C. for 5 minutes to form strain on the surface of the polymer A layer. Drawing at a temperature higher than the melting point of the low-melting polymer by 20° C. or more and 100° C. or less is preferably used from the viewpoint of achieving both the mobility of the domains of the low-melting polymer and the accumulation of strain for the movement.

The first film of the present invention has the following formula (II) from the viewpoint of improving the smoothness of the functional film and the peelability after heating when used as a process substrate for producing a functional film. is preferably satisfied.
1 nm≦(Rm2−Rm1)≦2.0×10 ⁴ nm (II)
By setting (Rm2-Rm1) to 1 nm or more, the first film of the present invention exhibits good peelability after heating. (Rm2-Rm1) is more preferably 3 nm or more from the viewpoint of improving the peelability after heating. Further, by setting (Rm2−Rm1) to 2.0×10 ⁴ nm or less, the smoothness of the functional film and the functions associated with the smoothness are improved. (Rm2-Rm1) is more preferably 1.0×10 ³ nm or less, more preferably 100 nm or less, and particularly 50 nm or less, from the viewpoint of improving the smoothness of the functional film and the functions associated with the smoothness. Preferably, 20 nm or less is most preferable.

As a method for making (Rm2-Rm1) within the range of formula (II), the polymer A layer is configured by combining two or more types of polymers, and after stretching the polymer A layer, In the method of deforming only the polymer with the low melting point among the polymers by heating at 180° C. for 5 minutes to form strain on the surface of the polymer A layer, the polymer with the low melting point among the polymers contained in the polymer A layer is side-fed. A method of putting it into an extruder is mentioned. By feeding only the low-melting polymer by side feeding, the temperature of the low-melting polymer is much higher than the melting point (for example, the extrusion temperature suitable for the polymer with a high melting point as the main component contained in the polymer A layer). It is possible to suppress the decrease in dispersibility with the main component polymer of the polymer A layer due to the low melt viscosity. As another method, the polymer A layer is configured to contain a crystalline polymer, microcrystals are formed in the polymer A layer by UV treatment or plasma treatment, and only the amorphous part around the microcrystals is heated at 180 ° C. for 5 minutes. In the method of thermally exercising to form strain on the surface of the polymer A layer, the method of adjusting the surface treatment conditions such as UV treatment and plasma treatment and the concentration of the crystalline polymer in the polymer A layer, the method of adjusting the concentration of the crystalline polymer in the polymer A layer, In the method in which voids are formed and the polymer around the voids is softened by heating at 180° C. for 5 minutes to change the shape of the voids and strain is formed on the surface of the polymer A layer, the size of the voids is adjusted to a specific range. methods and the like.

The first film of the present invention is a process base for producing a functional film, where Ra2 (nm) is the arithmetic mean roughness of the polymer A layer obtained by AFM after heat treatment at 180 ° C. for 5 minutes. When used as a material, it preferably satisfies the following formula (III) from the viewpoint of improving the smoothness of the functional film and the peelability after heating.
6≦(Rm2/Ra2)≦15 (III)
Here, Ra2 (nm) is a value obtained as follows. In an AFM (atomic force microscope) such as "NanoScope V Dimension Icon" manufactured by Bruker AXS, a silicon cantilever was applied as a probe, and the surface shape of the film was subjected to heat treatment at 180 ° C. for 5 minutes in tapping mode. Using software attached to the AFM (for example, NanoScope Analysis, etc.), the arithmetic mean roughness was calculated under the conditions of a cutoff of 3 nm. Such measurements are repeated 5 times, and the average value of the 5 measurements is obtained. In addition, the measurement direction (scanning direction of the probe) is an arbitrary direction and a direction orthogonal to the arbitrary direction, and the average value of the arithmetic average roughness in each direction (that is, An average value of 10 measurements (5 measurements in an arbitrary direction and 5 measurements in a direction perpendicular to the arbitrary direction) is adopted as Ra2 (nm). (Rm2/Ra2) is the value obtained by dividing the maximum height in the AFM after heat treatment at 180°C for 5 minutes in the polymer A layer by the arithmetic mean roughness in the AFM after heat treatment at 180°C for 5 minutes, The smaller the Rm2/Ra2), the smaller the maximum height with respect to the arithmetic mean roughness in AFM. In addition, the larger the (Rm2/Ra2), the larger the maximum height with respect to the arithmetic mean roughness in AFM, that is, the tendency that the difference between the maximum peak height of the unevenness obtained by AFM and the height of other peaks is large. show. In the case of applying the film as a process base material for producing a functional film, if (Rm2/Ra2) is too small, the peaks other than the peaks with the maximum height are generally low, and the heating with the functional film The subsequent peelability may be insufficient, and if (Rm2/Ra2) is too large, the peaks other than the peaks with the maximum height will be raised overall, and the smoothness of the functional film may be insufficient. be. Therefore, in the film of the present invention, by setting (Rm2/Ra2) within the range of formula (III), it is possible to achieve both the smoothness of the functional film and the releasability after heating within a high range. Furthermore, (Rm2/Ra2) is a value that correlates with the surface shape of the functional film, and is used in applications where functional films are laminated (for example, circuit members such as chip laminated ceramic capacitors and chip inductors). application), by setting (Rm2/Ra2) in the range of formula (III) instead of Rm2 (nm) or Ra2 (nm), the gap in the laminated portion when the functional films are laminated can be appropriately adjusted. It is also possible to improve various characteristics (for example, miniaturization and height reduction during lamination) when the functional film is formed into a laminate. (Rm2/Ra2) of the film of the present invention is more preferably 7 or more and 14 or less, particularly preferably 8 or more and 12 or less, from the viewpoint of achieving both peelability and smoothness of the functional film.

As a method for setting (Rm2/Ra2) to a desired range, the polymer A layer is configured by combining two or more types of polymers, and after stretching the polymer A layer, the polymer contained in the polymer A layer In the method of deforming only the low melting point polymer by heating at 180 ° C. for 5 minutes to form strain on the surface of the polymer A layer, the concentration of the low melting point polymer with respect to the entire polymer A layer and the thickness of the polymer A layer are set to a specific range. The method of adjustment, the polymer A layer is configured to contain a crystalline polymer, microcrystals are formed in the polymer A layer by UV treatment or plasma treatment, and only the amorphous part around the microcrystals is removed by heating at 180 ° C. for 5 minutes. In the method of forming distortion on the surface of the polymer A layer by thermal motion, the method of adjusting the surface treatment conditions such as UV treatment and plasma treatment and the concentration of the crystalline polymer in the polymer A layer. is formed, and the polymer around the voids is softened by heating at 180 ° C. for 5 minutes to change the shape of the voids and create strain on the surface of the polymer A layer. etc.

When the first film of the present invention is used as a process substrate for producing a functional film, when the arithmetic average roughness of the polymer A layer obtained by AFM is Ra1 (nm), after heating From the viewpoint of improving the releasability of the film, it is preferable to satisfy the following formula (IV).
(Rm2/Ra2)-(Rm1/Ra1)>0 (IV)
Here, Ra1 (nm) is a value obtained as follows. In AFM (atomic force microscope) such as "NanoScopeV Dimension Icon" made by Bruker AXS, a silicon cantilever is applied as a probe and the surface shape of the film is measured in tapping mode. Scope Analysis, etc.) was used to calculate the arithmetic mean roughness under the condition of a cutoff of 3 nm. Such measurements are repeated 5 times, and the average value of the 5 measurements is obtained. In addition, the measurement direction (scanning direction of the probe) is measured in two directions, one arbitrary direction and the direction perpendicular to the arbitrary one direction, and the average value of the arithmetic average roughness in each direction is Ra1 (nm). Compared to the value (Rm1/Ra1) before heating the film, by increasing the value (Rm2/Ra2) after treatment at 180°C for 5 minutes, the peaks other than the maximum height after heating Since the height is increased or the maximum peak height after heating is decreased, interlaminar strain between the polymer A layer and the functional film can be easily formed, and peelability after heating can be improved.

Regarding (Rm1/Ra1) and (Rm2/Ra2), as a method for satisfying the relationship of the formula (IV), the polymer A layer is configured by combining two or more types of polymers, and after stretching the polymer A layer In the method of deforming only the low-melting polymer among the polymers contained in the polymer A layer by heating at 180 ° C. for 5 minutes to form strain on the surface of the A layer, the type and concentration of the low-melting polymer are used as specific components. In the method, the polymer A layer contains a crystalline polymer, microcrystals are formed in the polymer A layer by UV treatment or plasma treatment, and only the amorphous part around the microcrystals is heated by heating at 180 ° C. for 5 minutes. In the method of forming strain on the surface of the polymer A layer by motion, the surface treatment conditions such as UV treatment and plasma treatment and the concentration of the crystalline polymer in the polymer A layer are adjusted. A method in which the polymer around the voids is softened by heating at 180° C. for 5 minutes to change the shape of the voids and strain is formed on the surface of the polymer A layer, and the size of the voids is set to a specific range. is mentioned.

[Second film]
The second film of the present invention is a film having a polymer A layer on at least one side, and the surface free energy of the polymer A layer is SE1 (mN/m), and after heat treatment at 180 ° C. for 5 minutes, the polymer A layer is When the surface free energy is SE2 (mN/m), it is important to satisfy the following formula (a).
SE1-SE2>0mN/m (a)
Here, SE1 (mN/m) and SE2 (mN/m) are values obtained as follows. Water, ethylene glycol, formamide, and methylene iodide were measured using a contact angle meter (Kyowa Interface Science CA-D type) on a film that had been conditioned for 24 hours under conditions of 23°C and 65% RH. A contact angle meter CA-D manufactured by Kyowa Kaimen Kagaku Co., Ltd. was used to determine the static contact angle with respect to the film surface using four kinds of measurement liquids. Each component of the contact angle and the surface tension of the liquid to be measured obtained for each liquid was substituted into the following equations, and four simultaneous equations were solved for γ ^L , γ ⁺ , and γ ⁻ .

(γ ^L γ _j ^L ) ^1/2 + 2(γ ⁺ γ _j ^- ) ^1/2 + 2(γ _j ⁺ γ ^- ) ^1/2 = (1 + cos θ)[γ _j ^L + 2(γ _j ⁺ γ _j ^- ) ^{1 /2} ]/2
However, γ = γ ^L + 2 (γ ⁺ γ _- ) ^1/2 γ _j = γ _j ^L + 2 (γ _j ⁺ γ _j ^- ) ^1/2 where γ, γ ^L , γ ⁺ and γ ^- are respectively , the surface free energy of the film surface, the long-range force term, the Lewis acid parameter, and the Lewis base parameter, and γ _j , γ _j ^L , γ _j ⁺ , γ _j ⁻ are the surface free It shall represent the energy, the long-range force term, the Lewis acid parameter, and the Lewis base parameter.

As the surface tension of each liquid used here, the values in Table 7 proposed by Oss ("Fundamentals of Adhesion", L.H. Lee (Ed.), p153, Plenum ess, New York (1991)) were used.

In the present invention, the heat treatment at 180° C. for 5 minutes is a treatment simulating the heating of the film to dry the functional film and improve its functionality when the film is used as a process substrate for the functional film. , for example, refers to a process in which the film is conveyed to a hot air circulation type conveyor oven set at 180° C. for 5 minutes. When transporting the film, the film is sandwiched between two metal frames, and then the metal frames are fixed with a metal clip so that the film does not come into direct contact with the conveyor.

In the present invention, formula (a) indicates that the surface free energy of the polymer A layer decreases after heat treatment at 180° C. for 5 minutes. By reducing the surface free energy of the polymer A layer after heating, for example, when the film of the present invention has a structure in which it is laminated with a functional film, the adhesion when producing the functional film, drying, etc. It was found that the peelability of the functional film after heating by is compatible.

As a method for making SE1-SE2 within the range of formula (a), the polymer A layer contains a small amount of a polymer containing a hydrophobic portion, and the polymer containing a hydrophobic portion is placed on the island side of the polymer A layer. , a method of arranging the hydrophobic portion on the film surface after heating, and the like. The sea-island structure of the polymer A layer can be confirmed by cross-sectional TEM observation or the like after dyeing the film by a known method.

The second film of the present invention has the following formula (b) from the viewpoint of improving the smoothness of the functional film and the peelability after heating when it is used as a process base material for producing a functional film. is preferably satisfied.
0.5mN/m≦(SE1−SE2)≦40mN/m (b)
In the film of the present invention, when (SE1-SE2) is 0.5 mN/m or more, the peelability after heating is improved. (SE1-SE2) is more preferably 2 mN/m, particularly preferably 5 mN/m or more, from the viewpoint of improving the peelability after heating. Further, by setting (SE1-SE2) to 40 mN/m or less, the releasability becomes higher than necessary after heating, and it is possible to prevent the separation from the functional film and the occurrence of floating during processing. (SE1-SE2) is more preferably 30 mN/m or less from the viewpoint of improving the releasability of the functional film and suppressing the occurrence of peeling and lifting during processing.

As a method for making (SE1-SE2) within the range of formula (b), the polymer A layer contains a small amount of a polymer containing a hydrophobic portion, and the polymer containing a hydrophobic portion is added to the sea-island structure of the polymer A layer. In the method of placing on the island side and arranging the hydrophobic portion on the film surface after heating, the weight ratio of the polymer containing the hydrophobic portion to the polymer A layer and the ratio of the hydrophobic portion of the polymer containing the hydrophobic portion are adjusted. methods and the like. Furthermore, if various surface treatments such as corona treatment are performed before heating, the hydrophobic portion is pulled out to the surface, so that the surface free energy tends to decrease after heating. Therefore, various surface treatments (corona treatment, plasma treatment, UV treatment, etc.) that are originally used for hydrophilization of films are also used to hydrophobize the polymer A layer after heating to make it within the range of formula (b). It is effective as a method.

The film of the present invention preferably satisfies the following formula (c) from the viewpoint of the coatability of the functional film and the adhesion of the functional film after heating.
25mN/m≤SE1≤70mN/m (c)
SE1 is the surface free energy of the polymer A layer before heating, and when it is 25 mN/m or more, it is preferable because the coatability of the functional film to the polymer A layer is improved, more preferably 35 mN/m or more, especially It is preferably 42 mN/m or more. Also, considering the peelability between the polymer A layer and the functional film after heating, SE1 is preferably 70 mN/m or less, more preferably 48 mN/m or less, even before heating.

Examples of methods for adjusting SE1 to a desired range include a method of adjusting the composition of the polymer A layer and various surface treatments. The second film of the present invention satisfies the relationship of the following formula (d), where Sd2 is the dispersion force of the polymer A layer and Sp2 is the polar force after heat treatment at 180 ° C. for 5 minutes. This is preferable from the viewpoint of film homogeneity.

23mN/m≦(Sd2−Sp2)≦36mN/m (d)
Here, (Sd2-Sp2) is a value related to the polarity of surface free energy, the smaller (Sd2-Sp2) the higher the polarity of the polymer A layer, and the larger becomes less polar. In the second film of the present invention, by lowering the polarity of the polymer A layer after heating, when the functional material is applied, the polar portion of the functional material tries to approach the polar portion of the polymer A layer, and the functional property is reduced. It is possible to suppress non-uniform dispersibility of the film and improve various functions of the functional film. Incidentally, (Sd2-Sp2) can be obtained from the difference between Sd2 (mN/m) and Sp2 (mN/m) calculated by the method described later in Examples. (Sd2-Sp2) is more preferably 17 mN/m or more and 27 mN/m or less from the viewpoint of improving the function of the functional film. Examples of the method for making (Sd2−Sp2) fall within the range of formula (d) include a method of adjusting the composition of the polymer A layer and various surface treatments. Specifically, the intrinsic viscosity of the polymer containing the hydrophobic portion contained in the polymer A layer is made 0.5 or more lower than the intrinsic viscosity of the polymer that is the main component of the polymer A layer, and the hydrophobic component is reduced after heating. The mobility of the polymer containing the hydrophobic portion is relatively high so that it is easy to manifest on the film surface, and the heat treatment temperature after stretching during film formation is set within a range that does not exceed the melting point of the polymer A layer. The temperature is set as high as possible, and various surface treatments such as corona treatment and UV treatment are performed under extremely weak conditions compared to the conditions that improve the wettability of conventional films. a method of applying kinetic energy to the film within a range that does not impair the adhesion with various functional films.

[First and second films]
In the first and second films of the present invention, the resin constituting the polymer A layer is not particularly limited as long as it satisfies the various requirements of the present invention. Polyolefin resins such as polyolefin resins, modified polyolefin resins having side chains (including structures substituted with metal ions) such as carboxylic acid and maleic anhydride in polyolefin resins, polyethylene terephthalate, polytetramethylene terephthalate, polybutylene terephthalate, And polyester resins, acrylic resins, polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene obtained by copolymerizing these with glycol components other than ethylene glycol, tetramethylene glycol and butanediol, and carboxylic acid components other than terephthalic acid.・Fluorine-based resins such as perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, polycarbonate-based resins, polyurethane resins, polyvinyl chloride resins, polystyrene resins, ABS (acrylonitrile-butadiene-styrene copolymer) resins, AS (acrylonitrile-styrene copolymer) resins, and the like.

Among these, it is preferable that the main component of the polymer A layer is a polyester-based resin from the standpoint of not causing large deformation when heated at 180° C. and from the standpoint of cost.

The polyester-based resin in the present invention refers to a polymer in which a structural unit derived from dicarboxylic acid (dicarboxylic acid component) and a structural unit derived from diol (diol component) are bonded via an ester bond.

Examples of dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, Aromatic dicarboxylic acids such as 4,4′-diphenyletherdicarboxylic acid and 4,4′-diphenylsulfonedicarboxylic acid, Aliphatic dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid and cyclohexanedicarboxylic acid , and ester derivatives with various aromatic dicarboxylic acids and aliphatic dicarboxylic acids. These diol components may be of one type other than ethylene glycol, or may be used in combination of two or more types.

The diol component includes ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1 ,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxy phenyl)propane, isosorbide, spiroglycol, and the like. These dicarboxylic acid components may be of one type other than ethylene glycol, or may be used in combination of two or more types.
Among these dicarboxylic acid components and diol components, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable as the dicarboxylic acid component from the viewpoint of solvent resistance and heat resistance, and ethylene glycol as the diol component. , 1,4-butanediol, 1,4-cyclohexanedimethanol, isosorbide and spiroglycol are preferably used.

[First film]
The polymer A layer of the first film of the present invention may contain at least one type of polymer different from the main component polymer from the viewpoint of increasing the maximum height of the polymer A layer obtained by AFM after heating. preferable. As the polymer different from the main component polymer, a portion having high compatibility with the main component polymer and a portion having high compatibility with the main component polymer are selected from the viewpoint of causing the portion having low compatibility to move by heating to form strain at the interface between the polymer A layer and the functional film. Polymers having both configurations of less compatible moieties are preferably selected. In addition, since the polymer different from the main component polymer increases the difference in orientation relaxation from the main component polymer of the polymer A layer when heated, making it easier to form strain at the interface between the polymer A layer and the functional film, It preferably has a lower melting point than the main component polymer. The melting point of the polymer different from that of the main component polymer is preferably 15° C. or more, more preferably 30° C. or more, lower than that of the main component polymer. In addition, the main component polymer may be an amorphous polymer that does not have a melting point. In the case of an amorphous polymer, the polymer A layer is 100% by mass so that the film does not deform even when heated at 180 ° C. It is preferable that the concentration is 20% by mass or less with respect to the In addition, as a polymer different from the main component polymer, fine voids are formed in the polymer A layer, and after heating, the shape of the voids is changed to form strain at the interface between the polymer A layer and the functional film. A polymer having low compatibility with the polymer of the main component of the polymer A layer and having a similar melt viscosity is preferably selected.

As an example of the polymer A layer of the first film of the present invention, the main component is a polyester-based resin, and in the case of polyethylene terephthalate among the polyester-based resins, the portion that is highly compatible with the main component polymer and the low compatibility are low. Examples of polymers having both configurations of moieties include block copolymers of polybutylene terephthalate and polyoxyalkylene glycol (polybutylene terephthalate is a moiety highly compatible with polyethylene terephthalate, and polyoxyalkylene glycol is a moiety highly compatible with polyethylene terephthalate). low compatibility portion), various modified polyolefin resins (modified functional groups are highly compatible with polyethylene terephthalate, polyolefin portion is low compatibility with polyethylene terephthalate), and the like. In addition, as polymers with low compatibility with the main component polymer, various polyolefin resins have melt viscosity characteristics similar to the main component polymer (polyethylene terephthalate in this example) at the melt extrusion temperature of the main component polymer. polymers and the like.

[Second film]
From the viewpoint of reducing the surface free energy after heating, the polymer A layer of the second film of the present invention preferably contains at least one polymer different from the main component polymer. As a polymer different from the main component polymer, from the viewpoint of reducing the surface free energy after heating and achieving both film quality, it is necessary to have both a portion that is highly compatible with the main component polymer and a portion that is not compatible with the main component polymer. Polymers are preferably selected that have a low compatibility fraction that is hydrophobic with respect to the high compatibility fraction.

As an example of the polymer A layer of the second film of the present invention, the main component is a polyester-based resin, and among the polyester-based resins, when polyethylene terephthalate is used, the portion that is highly compatible with the main component polymer and the low compatibility are low. Examples of polymers having both of the configurations of moieties include block copolymers of polybutylene terephthalate and polyoxyalkylene glycol (polybutylene terephthalate is a moiety highly compatible with polyethylene terephthalate, and polyoxyalkylene glycol is polyethylene terephthalate portion having low compatibility with polyethylene terephthalate), various modified polyolefin resins (portion having modified functional group compatible with polyethylene terephthalate), and the like. On the other hand, when combined with various surface treatments before heating, a method of directly copolymerizing polyethylene terephthalate with a structure having low compatibility with polyethylene terephthalate, such as polyoxyalkylene glycol, also reduces the surface free energy after heating. It is preferable from the viewpoint of

[First and second films]
In the first and second films of the present invention, the glossiness (60°) of the polymer A layer after heating at 180°C for 5 minutes is 30 or more from the viewpoint of improving the appearance of the functional film and the properties associated with smoothness. is preferably Here, the glossiness (60°) refers to the glossiness under the condition that the incident angle is 60°. The functional film is preferably smooth in order to improve the characteristics of reflecting electromagnetic waves and various electrical characteristics when a plurality of functional films are laminated to form a circuit member. As an index of smoothness from such a viewpoint, the glossiness of the polymer A layer onto which the functional film is transferred can be preferably used. The glossiness (60°) of the polymer A layer after heating at 180°C for 5 minutes is more preferably 50 or more, still more preferably 70 or more, and particularly preferably 80 or more. In addition, the glossiness (60°) of the polymer A layer is preferably 200 or less, more preferably 155 or less, from the viewpoint of handleability of the functional film.

As a method for adjusting the glossiness (60°) of the polymer A layer after heating at 180°C for 5 minutes to the desired range, the type and size of various particles contained in the polymer A layer for imparting winding properties. There is a method of adjusting the thickness.

In the first and second films of the present invention, the indentation elastic modulus of the polymer A layer is 800 N/mm ² from the viewpoint of suppressing dents on the film and marks when foreign matter is caught and improving the quality of the functional film. It is preferable that it is 6,000 N/mm ^{2 or more and 6,000 N/mm 2} or less. Here, the indentation elastic modulus is an evaluation method that can measure the hardness and elastic modulus of a minute region or thin film, called the nanoindentation method. Therefore, even if the film receives an impact or is stacked with foreign matter caught in it, dents and marks caused by foreign matter are less likely to occur. Good surface quality can be achieved.

In the first and second films of the present invention, as a method for making the indentation modulus of the polymer A layer 800 N/mm ² or more and 6,000 N/mm ^{2 or} less, the composition of the film (melting point, two or more raw material alloy), production conditions (biaxial stretching treatment, stretching temperature and stretching ratio in the treatment, etc.), and the like.

The first and second films of the present invention provide good handleability when used as a process base material for applying a functional material to obtain a thin film of a functional material layer (functional film). Therefore, it is preferable that the tear propagation resistance is 4.0 N/mm or more and 12.0 N/mm or less in the main orientation axis direction and in the direction perpendicular to the main orientation axis. Here, the tear propagation resistance refers to a value measured according to JIS K-7128-2-1998, and the larger the value, the more difficult it is to tear. Further, the main orientation axis in the present invention is the direction obtained by using a microwave molecular orienter, and the direction orthogonal to the main orientation axis is obtained based on the main orientation axis direction using the microwave molecular orienter. direction. The main orientation axis of the film is the in-plane direction in which the molecular chains of the polymer composing the film are most strongly oriented. ("KOBRA" series manufactured by Oji Keisoku Kiseki Co., Ltd.), Abbe refractometer ("DR-A1" series, "NAR" series manufactured by Atago Co., Ltd.), etc. In biaxially oriented films, the orientation of the molecular chains is generally weakest in the direction perpendicular to the main orientation axis. By determining the tear propagation resistance in two directions, it is possible to identify the highest and lowest tear propagation resistance values in the film plane. That is, since the upper and lower limits of the tear resistance of the film are known, it can be confirmed that the handleability is good in any direction.

The tear propagation resistance is more preferably 4.5 N/mm or more, particularly preferably 5.5 N/mm or more, and most preferably 6.0 N/mm or more, from the viewpoint of good handleability when used as a process substrate. preferable. Further, the film of the present invention more preferably has a tear strength of 9.8 N/mm or less from the viewpoint of improving the peelability of the functional film after processing. As a method for adjusting the tear strength of the film to the range of 4.0 N/mm or more and 12.0 N/mm or less, a layer containing only a small amount of a polymer having a lower melting point than the main component polymer constituting the film, or a low melting point polymer A method of setting the total thickness of the film to a specific range by forming a laminated structure in which a layer containing no

The first and second films of the present invention, when used as a process base material, can have good coatability, peelability after processing, and scratch resistance. It can be preferably used as a manufacturing process application of various functional films such as circuit members such as ceramic members and optical members.

In the present invention, the functional material constituting the functional film refers to a material used in various products for the purpose of expressing functions based on the various physical and chemical properties of the material. Examples include polymer materials, adhesives, pressure-sensitive adhesives, optical materials, ceramics, metal materials, and magnetic materials that have characteristics such as heat sensitivity.

Examples of polymer materials that have characteristics such as photosensitivity and heat sensitivity include acrylic resins that cure with light such as ultraviolet rays and lasers, or with heat, and are used for various resist materials, printing inks, surface protection of plastic materials, etc. It is preferably used in

Adhesives and pressure-sensitive adhesives include materials such as acrylic resins, silicone resins, polyvinyl alcohol resins, and epoxy resins. It is preferably used for processing applications such as materials, dicing tapes for manufacturing semiconductor chips, masking tapes for plating, and the like.

Optical materials include acrylic resins, polycarbonate resins, cyclic olefin resins, and other materials with characteristics such as transparency and retardation properties. It is preferably used for applications such as materials.

Ceramics include materials with dielectric properties and heat resistance, such as barium titanate, alumina, zirconia, silicon carbide, and zeolite. They are used in various digital electronic devices such as smartphones, and are used as capacitors, inductors, and circuit board materials. It is preferably used for various purposes.

Examples of metal materials include silver, copper, iron, and other materials that are characterized by electrical conductivity, heat dissipation, electromagnetic wave shielding, and barrier properties, and are preferably used for metal transfer foils and the like.

Examples of magnetic materials include ferrite, permalloy, and other materials that generate magnetic force, change shape, or change electrical resistance in a magnetic field, and are preferable for use in inductors, noise suppression, wireless communication, and wireless power supply. Used.

[First and second films]
Next, a preferred method for producing the first and second films of the present invention will be described below as an example in which a polyester-based resin is selected as the polymer A layer. The present invention should not be construed as being limited to such examples.

First, raw materials constituting the polymer A layer are supplied to a vented twin-screw extruder and melt extruded. When the polymer A layer and a layer other than the polymer A layer are laminated, the polyester A used for the polymer A layer and the polyester raw material used for the layer other than the polymer A layer are supplied to separate vented twin-screw extruders and melted. Extrude. Further, when polymer A layers having different compositions are laminated, the polyester A used for each polymer A layer is supplied to a separate vented twin-screw extruder and melt extruded. In the following, the polymer A layer and , and layers other than the polymer A layer (referred to as a polymer B layer) are laminated. When performing melt extrusion, the extruder is circulated in a nitrogen atmosphere, the oxygen concentration is 0.7% by volume or less, and the extrusion temperature of the resin is 5 ° C to 40 ° C higher than the melting point of the resin with the highest melting point among the layers. It is preferable to set the melting point, and in the case of only an amorphous resin whose melting point is not observed, it is preferable to adjust it within the range of 180° C. to 270° C., for example, while observing the melt viscosity and the melting state. Next, foreign substances are removed and the extrusion rate is made uniform through a filter or a gear pump. After the polymer A layer and the polymer B layer are combined, the mixture is discharged from a T-die onto a cooling drum in the form of a sheet. At that time, an electrostatic application method in which an electrode to which a high voltage is applied is used to statically adhere the cooling drum and the resin, a casting method in which a water film is formed between the casting drum and the extruded polymer sheet, and the casting drum temperature is changed to that of polymer A. A sheet-shaped polymer is brought into close contact with a casting drum, cooled and solidified, and unstretched by a method of adhering the extruded polymer at a glass transition point of -20 ° C. or a method combining a plurality of these methods. get the film. Among these casting methods, when a polyester-based resin is used, the method of applying static electricity is preferably used from the viewpoint of productivity and flatness.

Further, in the first film of the present invention, when the polymer A layer is composed of a combination of two or more types of polymers, a so-called side-feed type extruder that allows raw materials to be introduced from the melting zone of the extruder. is preferably used as an extruder for the polymer A layer. In addition, from the viewpoint of preventing the polymer A layer from having a non-uniform structure due to excessive heating of the low-melting-point polymer resulting in a low melt viscosity, a low-melting-point polymer among the polymers contained in the polymer A layer is preferably used from the side feed side.

The first and second films of the present invention are preferably biaxially oriented from the viewpoint of heat resistance and dimensional stability. It is preferable to stretch the film by a sequential biaxial stretching method in which the film is stretched in the longitudinal direction after the film is stretched to a thickness, or by a simultaneous biaxial stretching method in which the film is stretched substantially simultaneously in the longitudinal direction and the width direction. The biaxially oriented state of the film, for example, in the case of a film composed mainly of a polyester resin such as a polyethylene terephthalate resin, is determined by an Abbe refractometer or the like to determine the main orientation axis direction in the film plane and the main orientation axis in the film plane. and the thickness direction of the film are measured, and it can be confirmed from the fact that the refractive index in the thickness direction of the film is the smallest.

The stretching ratio in the stretching method is preferably 2.7 times or more and 4 times or less, more preferably 3 times or more and 3.5 times or less in the longitudinal direction. Moreover, it is desirable that the drawing speed is 1,000%/minute or more and 200,000%/minute or less. Moreover, the stretching temperature in the longitudinal direction is preferably 80° C. or higher and 130° C. or lower. The draw ratio in the width direction is preferably 2.8 times or more and 4 times or less, more preferably 3 times or more and 3.8 times or less. The stretching speed in the width direction is preferably 1,000%/min or more and 200,000%/min or less.

Furthermore, the film may be heat treated after biaxial stretching. The heat treatment can be performed by any conventionally known method such as in an oven or on heated rolls. The purpose of this heat treatment is to grow oriented crystals after the biaxial orientation and to improve the thermal dimensional properties. Therefore, the heat treatment temperature is set as high as possible within the range below the melting point of the polymer A layer, which has the highest melting point. is common.

Further, the polymer A layer of the first film of the present invention contains a small amount of a polymer having a melting point lower than that of the main component of the polymer A layer, thereby forming a low-orientation domain in the polymer A layer, It can be designed to facilitate the formation of surface strain in the polymer A layer after heating. When the polymer A layer has a structure in which two or more types of polymers are combined, a difference in orientation is provided between the main component polymer of the polymer A layer and the polymer contained in the polymer A layer and having a melting point lower than that of the main component. , From the viewpoint of making it easier to form strain at the interface between the polymer A layer and the functional film due to the difference in orientation relaxation during processing of the functional film, the heat treatment temperature of the film after biaxial stretching is the melting point of the polymer with a low melting point. More preferably, the temperature is 15°C or higher and 30°C or lower.

In addition, in the polymer A layer of the second film of the present invention, a polymer different from the main component of the polymer A layer (having both a configuration of a portion highly compatible with the polymer of the main component and a portion having low compatibility, By incorporating a small amount of a polymer in which the part with low solubility is hydrophobic with respect to the part with high compatibility), after heating, the part with low compatibility of the polymer (hydrophobic part), which is different from the main component, appears on the surface. By arranging them, the surface free energy of the A layer can be easily lowered.

In addition, in the first and second films of the present invention, the surface of the polymer A layer is subjected to corona treatment or plasma treatment in order to improve adhesion to the functional film before heating and peelability after heating. , UV treatment and other surface treatments may be performed, or an easy-adhesion layer and a release layer may be coated during the film manufacturing process.

In particular, when the polymer A layer of the second film of the present invention contains a polymer containing a hydrophobic moiety, the wettability of the film is conventionally improved under very weak conditions compared to the conditions for improving the wettability of the film. Then, by using a method of applying kinetic energy to a polymer containing a hydrophobic portion within a range that does not impair the adhesion with various functional films, the polarity of the polymer A layer is controlled within a specific range and the properties of the functional film are improved. , the quality can be good.

Methods for measuring properties and evaluating effects in the present invention are as follows. In the following, Examples 1 to 5, 8 to 12, 25, 29 to 31, 34, 35, 36, and 37 refer to Reference Examples 1 to 5, 8 to 12, 25, 29 to 31, 34, 35, 36 and 37 shall be read.

(1) Polymer Composition The composition of the polymer A layer was determined by a known polymer composition analysis method (FT-IR (Fourier transform infrared spectrophotometer), NMR (nuclear magnetic resonance), etc.). In the case where the polymer A layer contains polyester, after scraping the polymer A layer from the film, it was dissolved in hexafluoroisopropanol (HFIP) and each monomer residue was analyzed using ¹ H-NMR and ¹³ C-NMR. The contents of base components and by-product diethylene glycol were quantified. The composition of the film of the present invention was calculated from the mixing ratio at the time of film production.

(2) Intrinsic viscosity When it is confirmed that the polymer A layer tends to be polyester by a known polymer composition analysis method (FT-IR, NMR, etc.), the polymer A layer is dissolved in orthochlorophenol and measured using an Ostwald viscometer. was measured at 25°C using In the case of the laminated film, the intrinsic viscosity of each layer was evaluated by scraping off each layer of the film according to the laminated thickness.

(3) Film Thickness and Layer Thickness When measuring the film thickness, a dial gauge was used to measure the thickness of a sample cut out from the film at five arbitrary locations, and the average value was obtained. When measuring the layer thickness, the film was embedded in an epoxy resin, and the cross section of the film was cut out with a microtome. The cross section was observed with a transmission electron microscope (TEM H7100 manufactured by Hitachi, Ltd.) at a magnification of 5000 times to determine the thickness of each layer.

(4) Using a melting point differential scanning calorimeter (EXTRA DSC6220, manufactured by SII Nano Technology (formerly Seiko Electronics)), measurement and analysis were performed in accordance with JIS K-7121-1987 and JIS K-7122-1987. . 5 mg of film was used as a sample, and the temperature at the top of the endothermic peak obtained from the DSC curve when the temperature was raised from 25° C. to 300° C. at 20° C./min was taken as the melting point. In the case of a laminated film, the melting point of each layer was measured by scraping off each layer of the film, and when multiple melting points were observed, the endothermic peak with the largest area was adopted as the melting point of the layer.

(5) Rm1, Ra1
In AFM (atomic force microscope) such as "NanoScope V Dimension Icon" made by Bruker AXS, a silicon cantilever is applied as a probe, and the surface shape of a film or a film subjected to heat treatment at 180 ° C for 5 minutes is measured in tapping mode. did. The scanning range was 3 μm square, the scanning speed was 0.4 Hz, and the measurement was performed at room temperature (25° C.) in the atmosphere. As a pretreatment for the measurement, the film was cut into pieces of about 1 cm square, and the measurement was performed after fixing the film to a silicon wafer with an epoxy resin. After that, using the software attached to the AFM (e.g., Nano Scope Analysis, etc.), the maximum height and arithmetic mean roughness were calculated under the condition of a cutoff of 3 nm, and the average value of 5 measurements was calculated for each. . The measurement direction (scanning direction of the probe) is an arbitrary direction and a direction orthogonal to the arbitrary one direction, and the maximum height in each direction and the average of the arithmetic average roughness The values (that is, the average value of a total of 10 measurements of 5 measurements in an arbitrary direction and 5 measurements in a direction orthogonal to an arbitrary direction) are Rm1 (nm) and Ra1 ( nm).

(6) Rm2, Ra2
A sample was prepared by sandwiching an A4 size film between two A4 size aluminum frames each having a thickness of 2 mm and having a width other than 1 cm on all four sides, and then fixing the aluminum frames with metal clips. Thereafter, the film was heat-treated in a conveyor type oven (FGJOA9H manufactured by Fujimac Co., Ltd.) set at 180° C. so that the oven passing time was set to 5 minutes. For the film after heating at 180 ° C. for 5 minutes obtained by the above method, the maximum height by AFM and the arithmetic average roughness were calculated in the same manner as in (5), and the average value of 5 measurements in each was calculated. Calculated. The measurement direction (scanning direction of the probe) is an arbitrary direction and a direction orthogonal to the arbitrary one direction, and the maximum height in each direction and the average of the arithmetic average roughness The values (that is, the average value of a total of 10 measurements of 5 measurements in an arbitrary direction and 5 measurements in a direction orthogonal to an arbitrary direction) are Rm2 (nm) and Ra2 ( nm).

(7) Using an indentation modulus nanoindenter (manufactured by Elionix, ENT-2100), apply a drop of "Aron Alpha Pro Impact Resistant" (manufactured by Toagosei, adhesive) on one side of the film and fix it on the sample fixing table. Then, measurement was performed using the remaining surface as the measurement surface. A triangular pyramidal diamond indenter (Berkovich indenter) with an edge-to-edge angle of 115° was used for the measurement. The measured data was processed using dedicated analysis software (version 6.18) for "ENT-2100" to obtain the indentation modulus. After that, the measurement surface was reversed and the same measurement was performed to obtain the indentation elastic modulus of both surfaces.

(8) A 5 mm square piece of polyester film (manufactured by Toray, "Lumirror" S10 (50 μm)) placed on an iron plate was covered with 10 films used for evaluation in a stacked state. After that, a 500 g weight (cylindrical with a diameter of 20 mm and a height of 28 mm) was left for 1 hour at the position covered with the piece of polyester film. After that, the weight is removed, the film is photographed one by one with a non-contact surface / layer cross-sectional shape measurement system (Ryoka System, VertScan2.0 RG300GL-Lite-AC), and the photographed screen is converted to polynomial 4 by the attached analysis software. The surface shape was measured by correcting the surface using the following approximation. Of the 10 films in total, the number of films in which a level difference of 5 μm or more was confirmed was evaluated according to the following criteria.
The camera used for photographing was a Sony HR-57 (1/2 inch), the wavelength filter was 530 nm white, the measurement software was VS-Measure Version 5.5.1, and the analysis software was VS-Viewer Version 5.5. 1 were used respectively.
A: 2 or less B: 3 or more and 4 or less C: 5 or more.

(9) Adhesion with functional film (Method 1)
A ferrite-based slurry was coated as a functional film on the polymer A layer side of the film so that the thickness after drying was 20 μm. The ferrite-based slurry includes 100 parts of soft magnetic ferrite powder (number average particle diameter 0.7 μm), 30 parts of polyvinyl butyral resin (“S-Lec BM-S” manufactured by Sekisui Chemical Co., Ltd.), a plasticizer (phthalate A slurry consisting of 5 parts of dioctyl acid) and 200 parts of a toluene/ethanol mixed solvent (mixing ratio: 6:4) was used, and the drying conditions were 100° C. for 5 minutes. Nitto Denko OPP adhesive tape (Danpron Ace No. 375) was attached to the functional film side of the obtained film/functional film (layer obtained by drying the ferrite-based slurry), and the width was 10 mm. A rectangular sample with a length of 150 mm was cut out. Part of the sample was peeled between the film/functional film layers, and a tensile tester (Tensilon UCT-100 manufactured by Orientec) was used to set the initial tension chuck distance to 100 mm and the tensile speed to 20 mm/min, and peel at 180°. did the test. Measurement was performed until the peel length reached 130 mm (distance between chucks: 230 mm), and the average value of the load over the peel length of 25 mm to 125 mm was taken as the peel strength. In addition, the measurement was performed 5 times and the average value was adopted. Adhesion to the functional film was evaluated based on the following criteria with respect to the peel strength thus obtained.
A: 0.030 N/10 mm or more, or not peelable B: 0.010 N/10 mm or more and less than 0.030 N/mm C: Less than 0.010 N/10 mm.

(10) Peelability from functional film (Method 1) (after heating)
After producing a film/functional film layer in the same manner as in (9), heat treatment was performed at 180° C. for 5 minutes in the same manner as in (6). After that, the peel strength was calculated by the same method as in (9). Thereafter, the peel strength obtained in (9) was compared with the peel strength after heat treatment at 180° C. for 5 minutes, and the peelability improvement effect after heating was evaluated according to the following criteria.
A: After heating at 180° C. for 5 minutes, the peel strength decreased by 0.01 N/10 mm or more, or peeling was not possible, but became peelable.
B: After heating at 180° C. for 5 minutes, the peel strength decreased by 0.005 N/10 mm or more and less than 0.01 N/10 mm.
C: After heating at 180° C. for 5 minutes, the peel strength exceeded 0 N/10 mm and decreased by less than 0.005 N/10 mm.
D: After heating at 180° C. for 5 minutes, the peel strength did not change or increased.

(11) Smoothness of functional film (method 1)
For the functional film peeled from the film in the same manner as in (10), the air inflow time from the gap between the glass and the functional film is was measured and evaluated according to the following criteria. In addition, if the air inflow time is long, even if the functional films are laminated, there are few gaps for air to flow in. This is an advantageous index for electrical properties and miniaturization of members in applications where functional films are laminated and used. be. The measurement conditions were a measurement area of 10 cm ² , a pressure of 100 kPa for fixing the functional film on the glass, a pressure of 0.05 MPa on the vacuum side at the start of measurement, and a pressure of 0.1 MPa on the atmosphere side. The time required for the pressure to change from 0.051 MPa to 0.052 MPa was defined as the air inflow time.
A: 20 minutes or more B: 5 minutes or more and less than 20 minutes C: 1 minute or more and less than 5 minutes D: Less than 1 minute.

(12) Glossiness of polymer A layer after heating at 180°C for 5 minutes For a film heat-treated at 180°C for 5 minutes in the same manner as in (6), Suga Using a digital variable angle gloss meter UGV-5D manufactured by Test Instruments, the 60° specular gloss of the polymer A layer side was measured. The measurement was performed with n=5, and the average value excluding the maximum and minimum values was taken as the glossiness. In addition, when measuring the glossiness, black drawing paper (GK8012 (thickness: 0.19 mm) manufactured by King Corporation) was placed on the back side of the measurement surface of the film.

(13) A sample with a size of 100 mm × 100 mm was cut out at an arbitrary point of the film in the direction of the main orientation axis or in a direction perpendicular to the direction of the main orientation axis, and a microwave molecular orientation meter MOA-2001A manufactured by KS Systems (now Oji Scientific Instruments) was used. (frequency 4 GHz), the in-plane main orientation axis direction of the polyester film was determined. Further, based on the obtained main orientation axis direction, the direction perpendicular to the main orientation axis direction was also determined.

(14) Tear Propagation Resistance Measured according to JIS K-7128-2-1998 using a heavy load tear tester (manufactured by Toyo Seiki). The sample was 75 mm x 63 mm in the main orientation axis direction and in the direction perpendicular to the main alignment axis direction, and a 20 mm deep cut was made at the center of the 75 mm side, and the remaining 43 mm was torn off. The tearing force (N) in the direction of the main orientation axis was obtained by reading the indicated value at the time. Next, the tear propagation resistance in the main orientation axis direction was obtained by dividing the tear force (N) in the main orientation axis direction read from the indicated value by the film thickness (mm). In addition, the measurement was performed 10 times each, and the average value of 10 times was adopted. In addition, measurement was performed in the same manner as above except that the measurement sample was 75 mm × 63 mm in the direction perpendicular to the main orientation axis direction and in the main orientation axis direction, respectively, and the tear propagation resistance in the direction perpendicular to the main orientation axis direction was obtained. Ta.

(15) Surface roughness Measured on both sides using a surface roughness meter (SE4000, manufactured by Kosaka Laboratory Ltd.). Measured under the conditions of a stylus tip radius of 0.5 μm, a measuring force of 100 μN, a measuring length of 1 mm, a low frequency cutoff of 0.200 mm, and a high frequency cutoff of 0.000 mm, the arithmetic mean roughness SRa in accordance with JIS B0601-2001. asked for

(16) Breaking elongation After determining the main orientation axis direction and the direction perpendicular to the main orientation axis direction by the method of (13), 150 mm × 30 mm (main orientation axis direction × direction perpendicular to the main orientation axis direction) A sample was prepared by cutting out into a rectangle. Set the sample in a tensile tester (Tensilon UCT-100 made by Orientec) so that the test length (initial tensile chuck distance (Sa)) is 50 mm, and the sample is broken at a tensile speed of 300 mm / min. A distance (Sb) was obtained. Sa and Sb were measured 10 times, and the average value of 10 times was obtained by the formula (Sb-Sa)/Sa×100, and the elongation at break (%) in the direction of the main orientation axis was taken. The elongation at break (%) in the direction perpendicular to the main orientation axis direction was also obtained by measuring a rectangular sample of 150 mm x 10 mm (direction perpendicular to the main orientation axis direction x main orientation axis direction). .

(17) Breaking strength When the breaking elongation in the direction of the main orientation axis is obtained by the method of (16), the stress when the sample breaks is read 10 times, and the average value of 10 times is the breaking strength in the direction of the main orientation axis. (MPa). Further, when the breaking elongation in the direction perpendicular to the main orientation axis direction was obtained by the method of (16), the stress when the sample broke was read 10 times, and the average value of 10 times was taken perpendicular to the main orientation axis direction. The breaking strength (MPa) in the direction of

(18) Workability (Method 1)
Prepare a film with a width of 300 mm and a length of 200 m (6 inches, 350 mm long core winding), rewind it on a 3 inch, 350 mm long core under the following conditions, and evaluate it according to the following criteria while varying and increasing the transport speed and tension. did
A: No breakage occurred even when rewound at a speed of 10 m/min and a conveying tension of 70 N/m.
B: No tear occurred even when rewinding at a speed of 5 m/min and a conveying tension of 50 N/m, but a tear occurred when the speed was changed to 10 m/min and a conveying tension of 70 N/m.
C: No tear occurred even when rewinding at a speed of 5 m/min and a conveying tension of 35 N/m, but a tear occurred when rewinding at a speed of 5 m/min and a conveying tension of 50 N/m.
D: Breakage occurred even when rewound at a speed of 5 m/min and a conveying tension of 35 N/m.

(19) Surface free energy SE1
Water, ethylene glycol, formamide, and methylene iodide were measured using a contact angle meter (Kyowa Interface Science CA-D type) on a film that had been conditioned for 24 hours under conditions of 23°C and 65% RH. A contact angle meter CA-D manufactured by Kyowa Kaimen Kagaku Co., Ltd. was used to determine the static contact angle with respect to the film surface using four kinds of measurement liquids. Each component of the contact angle and the surface tension of the liquid to be measured obtained for each liquid was substituted into the following equations, and four simultaneous equations were solved for γ ^L , γ ⁺ , and γ ⁻ .

(γ ^L γ _j ^L ) ^1/2 + 2(γ ⁺ γ _j ^- ) ^1/2 + 2(γ _j ⁺ γ ^- ) ^1/2 = (1 + cos θ)[γ _j ^L + 2(γ _j ⁺ γ _j ^- ) ^{1 /2} ]/2
However, γ = γ ^L + 2 (γ ⁺ γ _- ) ^1/2 γ _j = γ _j ^L + 2 (γ _j ⁺ γ _j ^- ) ^1/2 where γ, γ ^L , γ ⁺ and γ ^- are respectively , the surface free energy of the film surface, the long-range force term, the Lewis acid parameter, and the Lewis base parameter, and γ _j , γ _j ^L , γ _j ⁺ , γ _j ⁻ are the surface free It shall represent the energy, the long-range force term, the Lewis acid parameter, and the Lewis base parameter.

As the surface tension of each liquid used here, the values in Table 1 proposed by Oss ("Fundamentals of Adhesion", L.H. Lee (Ed.), p153, Plenum ess, New York (1991)) were used. The average value of five measurements was adopted as the static contact angle for each liquid to be measured.

(20) Surface free energy SE2
A sample was prepared by sandwiching an A4 size film between two A4 size aluminum frames each having a thickness of 2 mm and having a width other than 1 cm on all four sides, and then fixing the aluminum frames with metal clips. Thereafter, the film was heat-treated in a conveyor type oven (FGJOA9H manufactured by Fujimac Co., Ltd.) set at 180° C. so that the oven passing time was set to 5 minutes. For the film obtained by the above method after heating at 180° C. for 5 minutes, the surface free energy was determined by the same method as in (19), and was defined as SE2.

(21) Adhesion with functional film (Method 2)
A conductive paste was applied as a functional film on the polymer A layer side of the film so that the thickness after drying was 20 μm. As the conductive paste, 100 parts by mass of an epoxy adhesive (“AS-60” manufactured by Toagosei Co., Ltd.) and silver-coated copper powder with a 50% particle size (median diameter) of 5.9 μm (“Fukuda Metal Foil & Powder Co., Ltd.” A mixture of 150 parts by mass of Cu--HWQ (5 μm″) was used, and the drying conditions were 100° C. for 5 minutes. Nitto Denko OPP adhesive tape (Danpron Ace No. 375) is attached to the functional film side of the obtained film / functional film (layer obtained by drying the conductive paste), and the width is 10 mm, A rectangular sample with a length of 150 mm was cut out. A portion of the sample was peeled between the film and the functional film, and a tensile tester (Tensilon UCT-100 manufactured by Orientec) was used to set the initial tension chuck distance to 100 mm and the tensile speed to 20 mm/min. did the test. Measurement was performed until the peel length reached 130 mm (distance between chucks: 230 mm), and the average value of the load over the peel length of 25 mm to 125 mm was taken as the peel strength. In addition, the measurement was performed 5 times and the average value was adopted. Adhesion to the functional film was evaluated based on the following criteria with respect to the peel strength thus determined.
A: 0.030 N/10 mm or more, or not peelable B: 0.010 N/10 mm or more and less than 0.030 N/mm C: Less than 0.010 N/10 mm.

(22) Peelability from functional film (Method 2) (after heating)
After producing a film/functional film in the same manner as in (21), heat treatment was performed at 180° C. for 5 minutes in the same manner as in (20). After that, the peel strength was calculated in the same manner as in (21). Thereafter, the peel strength obtained in (21) was compared with the peel strength after heat treatment at 180° C. for 5 minutes, and the peelability improvement effect after heating was evaluated according to the following criteria.
A: After heating at 180° C. for 5 minutes, the peel strength decreased by 0.01 N/10 mm or more, or peeling was not possible, but became peelable.
B: After heating at 180° C. for 5 minutes, the peel strength decreased by 0.005 N/10 mm or more and less than 0.01 N/10 mm.
C: After heating at 180° C. for 5 minutes, the peel strength exceeded 0 N/10 mm and decreased by less than 0.005 N/10 mm.
D: After heating at 180° C. for 5 minutes, the peel strength did not change or increased.

(23) Uniformity of functional film After producing a film/functional film in the same manner as in (21), the surface resistivity of the functional film was measured and evaluated according to the following criteria. If the composition of the functional film is uniform, the metal contained in the functional film will be uniformly dispersed, and current will flow easily, so the surface resistivity will be small, which is an indicator of the uniformity of the functional film. . In addition, as a method for measuring the surface specific resistance, after cutting the film into 200 mm × 200 mm, after leaving it for 24 hours in a room conditioned at 23 ° C. and a relative humidity of 25%, under that atmosphere, the polymer A layer side was measured using a digital ultra-high resistance/micro current system R8340A (manufactured by ADVANTEST), the average value of 10 times was obtained, and then evaluated according to the following criteria.
A: 1.0×10 ⁸ Ω/sq or less B: Over 1.0×10 ⁸ Ω/sq and 1.0×10 ¹³ Ω/sq or less C: Over 1.0×10 ¹³ Ω/sq 1.0×10 ¹⁵ Ω/sq or less D: Value exceeding 1.0×10 ¹⁵ Ω/sq (24) Sd2, Sp2
Regarding the film heat-treated at 180° C. for 5 minutes in the same manner as in (20), the dispersion power Sd2 and the polar power Sp2 were obtained as follows. First, the following formula (e) was derived from the extended Fowkes formula and Young's formula.
[Extended Fowkes formula]
γSL = γS + γL −2 (γsd · γLd ) 1/2 −2 (γsD · γLD ) 1/2 −2 (γsh · γLh ) 1/2
[Young's formula]
γS = γSL + γL cos θ
γS: Surface free energy of solid γL: Surface tension of liquid γSL: Tension of interface between solid and liquid θ: Contact angle with liquid γsd, γLd: Dispersion force component of γS and γL γsD, γLD: Polar force of γS and γL Components γsh , γhL : Hydrogen bond components of γS, γL (γsd γLd ) 1/2 + (γsD γLD ) 1/2 + (γsh γLh ) 1/2 = γL (1 + cos θ)/2 (e )
Next, for four types of liquids with known surface tension components, the contact angle with a film that was subjected to heat treatment at 180 ° C. for 5 minutes was measured, substituted into formula (e), and ternary for each liquid By solving the linear simultaneous equations, the dispersion force component γsd and the polar force component γsD in the surface free energy of the film heat-treated at 180° C. for 5 minutes were adopted as Sd2 and Sp2, respectively. Numerical calculation software "Mathematica" was used to solve the simultaneous equations. Further, the contact angle was measured using a measuring liquid of water, ethylene glycol, formamide and methylene iodide, and a contact angle meter CA-D manufactured by Kyowa Interface Science Co., Ltd. was used as the measuring instrument. The average value of five measurements was adopted as the static contact angle for each liquid to be measured.

(25) Workability (Method 2)
Prepare a film with a width of 300 mm and a length of 200 m (6 inches, 350 mm long core winding), rewind it on a 3 inch, 350 mm long core under the following conditions, and evaluate it according to the following criteria while varying and increasing the transport speed and tension. did
A: No breakage occurred even when rewound at a speed of 10 m/min and a conveying tension of 70 N/m.
B: No tear occurred even when rewinding at a speed of 5 m/min and a conveying tension of 50 N/m, but a tear occurred when the speed was changed to 10 m/min and a conveying tension of 70 N/m.
C: Breakage occurred when rewinding at a speed of 5 m/min and a conveying tension of 50 N/m.

(26) Smoothness of functional film (method 2)
The functional film peeled off from the film in the same manner as in (22) was placed under a fluorescent lamp, and the visible image of the fluorescent lamp was evaluated according to the following criteria.
A: The outline of the fluorescent lamp was clearly confirmed.
B: Although the outline of the fluorescent lamp appears blurred, the state of the fluorescent lamp can be almost confirmed.
C: The outline of the fluorescent lamp could hardly be confirmed.

(27) A sample with a size of 100 mm × 100 mm was cut out at an arbitrary point of the film in the direction of the main orientation axis or in a direction perpendicular to the direction of the main orientation axis, and a microwave molecular orientation meter MOA-2001A manufactured by KS Systems (now Oji Scientific Instruments) was used. (frequency 4 GHz), the in-plane main orientation axis direction of the polyester film was determined. Further, based on the obtained main orientation axis direction, the direction perpendicular to the main orientation axis direction was also determined.
The following resins were used in the production of the films of the present invention.

(Polyester 1)
After producing a polyethylene terephthalate resin containing 100 mol % of terephthalic acid as a dicarboxylic acid component and 100 mol % of ethylene glycol as a glycol component, silica particles having a number average particle diameter of 2.2 μm are added to 100% by mass of the polyethylene terephthalate resin. Particle-containing polyethylene terephthalate resin (intrinsic viscosity: 0.63, melting point: 255°C).

(Polyolefin 2)
As the modified polyolefin resin to which maleic anhydride is bound, Sanyo Kasei's "Umex" 1001 (melting point: 142° C.) was used.
(Polyester 3)
A polyester resin (intrinsic viscosity: 1.1, melting point: 215° C.) obtained by block-copolymerizing 90% by mass of polybutylene terephthalate and 10% by mass of polytetramethylene glycol was used.

(Polyolefin 4)
Sumitomo Chemical's R101 (MFR=19, melting point 163° C.) was used as the polypropylene resin.

(Polyolefin 5)
As the cyclic polyolefin resin, "TOPAS" 8007F-04 (no melting point) manufactured by Polyplastics was used.

(Polyolefin 6)
"Himilan" 1707 (melting point 90°C) manufactured by Mitsui DuPont Polychemicals is used as a modified polyolefin resin in which a side chain obtained by replacing some of the hydrogen ions of methacrylic acid (carboxylic acid) with metal ions is bonded to a polyethylene-based main chain. ) was used.

(Acrylic 7)
A resin coating agent containing 74% by mass of “Finetac” CT-3088 manufactured by DIC and 26% by mass of thermally expandable microspheres (Microsphere F-50) was used.
(Polyester 8)
After producing a polyethylene terephthalate resin containing 100 mol % of terephthalic acid as a dicarboxylic acid component and 100 mol % of ethylene glycol as a glycol component, silica particles having a number average particle diameter of 3.5 μm are added to 100% by mass of the polyethylene terephthalate resin. Particle-containing polyethylene terephthalate resin (intrinsic viscosity: 0.63, melting point: 255°C).
(Polyester 9)
A polyester resin (intrinsic viscosity of 1.0, melting point of 213° C.) obtained by block-copolymerizing 85% by mass of polybutylene terephthalate and 15% by mass of polytetramethylene glycol was used.
(Polyester 10)
A polyester resin (intrinsic viscosity: 1.4, melting point: 218° C.) obtained by block-copolymerizing 90% by mass of polybutylene terephthalate and 10% by mass of polytetramethylene glycol was used.
(Polyester 11)
After producing a polyethylene terephthalate resin containing 100 mol % of terephthalic acid as a dicarboxylic acid component and 100 mol % of ethylene glycol as a glycol component, silica particles having a number average particle diameter of 3.5 μm are added to 100% by mass of the polyethylene terephthalate resin. Particle-containing polyethylene terephthalate resin (intrinsic viscosity: 0.65, melting point: 255°C).

(Polyester 12)
After producing a polyethylene terephthalate resin containing 100 mol % of terephthalic acid as a dicarboxylic acid component and 100 mol % of ethylene glycol as a glycol component, silica particles having a number average particle diameter of 2.2 μm are added to 100% by mass of the polyethylene terephthalate resin. Particle-containing polyethylene terephthalate resin (intrinsic viscosity of 0.63) containing 0.04% by mass of

(Polyolefin 13)
As the modified polyolefin resin to which maleic anhydride is bound, "Umex 1001" manufactured by Sanyo Chemical Industries, Ltd. was used.

(Polyester 14)
A resin (intrinsic viscosity of 0.57) obtained by block-copolymerizing 90% by mass of polybutylene terephthalate and 10% by mass of polytetramethylene glycol was used.

(Polyolefin 15)
Sumitomo Chemical's "R101" (MFR=19) was used as the polypropylene-based resin.

(Polyolefin 16)
As the cyclic polyolefin resin, "TOPAS8007F-04" manufactured by Polyplastics was used.

(Acrylic 17)
A resin coating agent containing 26% by mass of thermally expandable microspheres (Microsphere F-50) in 74% by mass of "Finetac CT-3088" manufactured by DIC was used.
An isophthalic acid-copolymerized polyethylene terephthalate resin (intrinsic viscosity: 0.7, melting point: 230°C) containing 90 mol% of terephthalic acid component and 10 mol% of isophthalic acid component as the dicarboxylic acid component, and 100 mol% of ethylene glycol component as the glycol component. .

(Polyester 18)
After producing a tetramethylene glycol copolymerized polyethylene terephthalate resin containing 100 mol % of terephthalic acid as a dicarboxylic acid component, 99.3 mol % of ethylene glycol as a glycol component, and 0.7 mol % of tetramethylene glycol, several A particle-containing polyethylene terephthalate resin (intrinsic viscosity of 0.65) containing 0.04% by mass of silica particles having an average particle size of 2.2 μm with respect to 100% by mass of polyethylene terephthalate resin.

(Polyester 19)
As a block-copolymerized resin of polybutylene terephthalate and polytetramethylene terephthalate, "Hytrel" 7247 manufactured by Toray DuPont was used.

(Example 1)
The composition is as shown in the table, polyester 1 is supplied to a normal feeder of a vented co-rotating twin-screw extruder with an oxygen concentration of 0.2% by volume, and polyolefin 2 is supplied from a side feeder of the co-rotating twin-screw extruder. The polymer layer A was melted at a cylinder temperature of 280°C in an extruder and extruded into a sheet from a T-die onto a cooling drum controlled at 25°C with a short tube temperature of 280°C and a nozzle temperature of 280°C. At that time, static electricity was applied using a wire-shaped electrode having a diameter of 0.1 mm, and the sheet was brought into close contact with a cooling drum to obtain an unstretched sheet. Next, the film was stretched 3.5 times in the longitudinal direction at a stretching temperature of 85°C and immediately cooled to 40°C with metal rolls. Next, the film is preheated at a preheating temperature of 85°C for 1.5 seconds in a tenter-type transverse stretching machine, stretched 3.5 times in the width direction at a stretching temperature of 100°C, and heat-treated as it is in the tenter at a heat treatment temperature of 245°C. went. A biaxially oriented polyester film having a thickness of 50 μm was obtained by performing heat treatment while shrinking the film by 5% in the width direction.

(Examples 2, 3, 6, 7, 8, 9, 11, 18, 19, 20, 21)
A biaxially oriented polyester film was obtained in the same manner as in Example 1, except that the composition and production conditions were changed as shown in the table.

(Example 4)
The ingredients were fed to separate vented co-rotating twin-screw extruders, each having an oxygen concentration of 0.2% by volume, with the composition shown in the table. For the polymer A layer, the polyester 1 was supplied to a normal feeder, the polyolefin 2 was supplied from a side feeder, and the cylinder temperature of the extruder for the polymer A layer was set to 280° C. to melt the raw materials. For the polymer B layer, polyester 1 was fed to a normal feeder and the extruder cylinder temperature was set to 280° C. to melt the raw materials. Thereafter, the same procedure as in Example 1 was carried out, except that the raw materials for the polymer A layer and the polymer B layer melted in the respective extruders were combined in the feed block so as to form a two-layer structure of A layer/B layer. to obtain a biaxially oriented polyester film.

(Examples 5, 13, 14, 15, 16, 17, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
A biaxially oriented polyester film was obtained in the same manner as in Example 4, except that the thickness of each layer was as shown in the table.

(Example 10)
Acrylic 7 was applied to a biaxially oriented polyester film “Lumirror” S10 (100 μm) manufactured by Toray Industries, and dried at 80° C. for 3 minutes to obtain a laminated film of polyester film and acrylic 7 .

(Example 12)
A biaxially oriented polyester film was obtained in the same manner as in Example 1, except that both polyester 1 and polyolefin 2 were supplied from a conventional feeder.

(Example 37)
A biaxially oriented polyester film was obtained in the same manner as in Example 12, except that the composition was as shown in the table.

(Comparative Examples 1 and 2)
A biaxially oriented polyester film was obtained in the same manner as in Example 1, except that the composition and production conditions were changed as shown in the table.

(Reference Example 1)
The composition is as shown in the table, and the raw materials are supplied to a vented co-rotating twin-screw extruder with an oxygen concentration of 0.2% by volume. was discharged in a sheet form from a T-die onto a cooling drum controlled at 25°C at a die temperature of 280°C. At that time, static electricity was applied using a wire-shaped electrode having a diameter of 0.1 mm, and the sheet was brought into close contact with a cooling drum to obtain an unstretched sheet. Next, the film was stretched 3.5 times in the longitudinal direction at a stretching temperature of 85°C and immediately cooled to 40°C with metal rolls. Next, the film was preheated at a preheating temperature of 85°C for 1.5 seconds in a tenter-type transverse stretching machine, stretched 3.5 times in the width direction at a stretching temperature of 100°C, and was directly in the tenter while shrinking in the width direction by 5%. The heat treatment was performed at a heat treatment temperature of 245°C. After that, the E value (= treatment intensity (W) / (treated electrode width (m) × film transport speed during corona surface treatment (m/min)), which is a measure of the irradiation intensity of the corona surface treatment, was applied to the obtained film. was set to 1 W·min/m ² and corona surface treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 50 μm.

(Reference Examples 2, 3, 6, 7, 8, 11, 15, 16, 20, 21)
A biaxially oriented polyester film was obtained in the same manner as in Reference Example 1, except that the composition and production conditions were changed as shown in the table.

(Reference Examples 4, 10, 12)
A biaxially oriented polyester film was obtained in the same manner as in Reference Example 1, except that the composition and production conditions were as shown in the table, and the E value in the corona surface treatment was 60 W·min/m ² .

(Reference Example 5)
A biaxially oriented polyester film was obtained in the same manner as in Reference Example 4, except that the E value of the corona surface treatment was changed to 50 W·min/m ² .

(Reference Examples 13, 17, 18)
The composition and production conditions are as shown in the table, and the raw materials are supplied to separate co-vented co-rotating twin-screw extruders with an oxygen concentration of 0.2% by volume, and the cylinder temperature of the extruder for polymer A layer is 280 ° C., B A biaxially oriented polyester film was obtained in the same manner as in Reference Example 1, except that the layers were melted at a cylinder temperature of 280°C in the layer extruder and merged to form a two-layer structure of A layer/B layer in the feed block. .

(Reference Example 9)
Acrylic 6 was applied to a biaxially oriented polyester film “Lumirror” S10 (100 μm) manufactured by Toray and dried at 80° C. for 3 minutes to obtain a laminated film of polyester film and acrylic 17 .

(Reference Example 14)
A biaxially stretched polyester film was obtained in the same manner as in Reference Example 1, except that the composition and production conditions were as shown in the table and the corona surface treatment was not performed.

(Reference Example 19)
The composition and production conditions are as shown in the table, and the raw materials are supplied to separate co-vented co-rotating twin-screw extruders with an oxygen concentration of 0.2% by volume, and the cylinder temperature of the extruder for polymer A layer is 280 ° C., B A biaxially oriented polyester was produced in the same manner as in Reference Example 1, except that the cylinder temperature of the layer extruder was melted at 280 ° C., and the three layers of A layer / B layer / A layer were combined in the feed block. got the film.

(Reference Comparative Examples 1 and 2)
A biaxially oriented polyester film was obtained in the same manner as in Reference Example 1, except that the composition and production conditions were changed as shown in the table.

The first and second films of the present invention can improve adhesion before heating and peelability after heating. It is preferably used as a process substrate.

Claims (7)

A film having a polymer A layer on at least one side, wherein the main component of the polymer A layer is a polyester-based resin, and polybutylene terephthalate and polyoxyalkylene glycol are used as polymers different from the polyester-based resin in which the polymer A layer is a main component. The maximum height of the polymer A layer obtained by AFM is Rm1 (nm), and the maximum height of the polymer A layer obtained by AFM after heat treatment at 180 ° C. for 5 minutes is Rm2. (nm), satisfies the following formula (I-2), and the glossiness (60°) of the polymer A layer after heat treatment at 180° C. for 5 minutes is 69 or more, in order to produce a functional film. process base film.
Rm2-Rm1≧3 nm (I-2) A process substrate film for producing a functional film according to claim 1, which satisfies the following formula (II-2).
3 nm≦(Rm2−Rm1)≦2.0×10 ⁴ nm (II-2) The functionality according to claim 1 or 2, which satisfies the following formula (III), where Ra2 (nm) is the arithmetic mean roughness of the polymer A layer obtained by AFM after heat treatment at 180 ° C. for 5 minutes. Process substrate film for manufacturing membranes.
6≦(Rm2/Ra2)≦15 (III) The process substrate film for manufacturing a functional film according to claim 1, which satisfies the following formula (IV).
(Rm2/Ra2)-(Rm1/Ra1)>0 (IV) The process substrate film for producing a functional film according to claim 1, wherein the indentation modulus of the polymer A layer is 800 N/ ^mm2 or more and 6,000 N/mm2 ^or less. 2. The process substrate for producing a functional film according to claim 1, wherein the tear propagation resistance is 4.0 N/mm or more and 12.0 N/mm or less in the main orientation axis direction and in the direction perpendicular to the main orientation axis. film. The process substrate film for producing a functional film according to any one of claims 1 to 6 , which is used as a process substrate for applying a ferrite-based slurry to obtain a functional film.