TW202028320A - Biaxially oriented thermoplastic resin film - Google Patents

Abstract

Provided is a biaxially oriented thermoplastic resin film, at least one surface of which satisfies the following conditions (1) and (2), and that has suitable smoothness and windability. (1) When the projection density for projections with a height of 10 nm or greater as measured by non-contact optical roughness measurement is denoted by A (projections/mm2), A is 2.0*10<SP>3</SP> to 2.5*10<SP>4</SP>. (2) When the projection density for projections with a height of 1 nm or greater but less than 10 nm as measured by atomic force microscopy (AFM) is denoted by B (projections/mm2), B is 1.8*10<SP>6</SP> to 1.0*10<SP>7</SP>.

Description

Biaxially oriented thermoplastic resin film

The present invention relates to a biaxially aligned thermoplastic resin film having coarse protrusions and fine protrusions on the surface layer.

Thermoplastic resins are used in various industrial fields due to their excellent workability. In addition, products made of these thermoplastic resins processed into films have played an important role in modern life such as industrial applications, optical product applications, packaging applications, and magnetic recording tapes. In recent years, the electronic information equipment has been evolving towards miniaturization and high integration, and the film used to manufacture electronic information equipment is required to improve its processability. Especially in the production of electronic information equipment, most of the methods are used to laminate other materials on the surface of the film, and perform optical processing such as photoresist for each film. Therefore, in order to improve the optical processability of the film, the general method is to improve the smoothness of the film surface while maintaining the transparency of the film, so that the laser light used for photoresist processing reduces light scattering due to the uneven shape of the film surface. . In addition, in the use of magnetic recording tapes, with the increase in the density of recorded data, it is required to improve the smoothness of the film surface to maintain the distance between the reading head and reduce the occurrence of error noise. Especially in the application of a coated magnetic recording tape, when only one side of the film used as a support is rough, there is a defect that the shape transfer occurs on the side of the smoother opposite side (magnetic recording layer) during roll winding. (Hereinafter, it may be referred to as a transfer defect), a problem that reduces the smoothness of the magnetic recording layer.

Generally to ensure coiling. Conveyance and contains particles in the film. borrow By reducing the particle content or reducing the particle diameter of the contained particles, the smoothness of the film can be improved or the above-mentioned transfer defects can be prevented. However, on the other hand, since there are no protrusions with high protrusion height in the winding step during film manufacturing and processing, the air that bites between the films cannot be released, and the floating parts become wrinkles and the quality is reduced. Situation.

In response to such a problem, for example, Patent Document 1 discloses a technique of making the film free of particles and using additives to roughen the surface.

[Prior Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2016-221853

However, in the case of using additives, although the surface roughness can be uniformly controlled by the concentration of the additives, there is a problem that the smoothness is greatly reduced due to the generation of coarse foreign matter from the additives.

In order to solve the above-mentioned problems, the inventors of the present case have found that by controlling the shape of the film surface, there are protrusions with higher protrusion heights locally to the extent that no transfer defects occur, and the height of the protrusions is lower. The coexistence of the protrusions allows for both smoothness and winding properties (hereinafter sometimes referred to as air release properties). In view of the foregoing, the present invention aims to provide a biaxially oriented thermoplastic resin film with good smoothness and rollability.

In order to solve the above-mentioned problems, the present invention adopts the following configuration. that is,

[I] A biaxially oriented thermoplastic resin film, the surface of at least one side meets the following (1) and (2);

(1) When the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement is A (pieces/mm ² ), A is 2.0×10 ³ or more and 2.5×10 ⁴ or less;

(2) When the number of protrusions with a height of 1 nm or more and less than 10 nm measured by an atomic force microscope (AFM: Atomic Force Microscope) is set to B (pieces/mm ² ), B is 1.8×10 ⁶ or more and 1.0×10 ⁷ or less.

[II] The biaxially oriented thermoplastic resin film according to [I], wherein the layer constituting the surface satisfying (1) and (2) contains particles having an average particle diameter of 10 nm or more and 300 nm or less.

[III] The biaxially oriented thermoplastic resin film as in [I] or [II], wherein the surface that satisfies (1) and (2) is at a height of 60 nm or more as measured by non-contact optical roughness measurement When the number of protrusions is C (pieces/mm ² ), C is 90 or less.

[IV] The biaxially oriented thermoplastic resin film of any one of [I] to [III], wherein it is used as a release film.

[V] The biaxially oriented thermoplastic resin film of any one of [I] to [III], which is used as a film for dry film photoresist support.

[VI] The biaxially oriented thermoplastic resin film according to any one of [I] to [III], which is used as a support film formed as a green sheet in a step of manufacturing a multilayer ceramic capacitor.

[VII] The biaxially oriented thermoplastic resin film as in any one of [I] to [III], which is a base film for magnetic recording media used in a coating type digital recording method.

The biaxially oriented thermoplastic resin film of the present invention has good smoothness and windability.

1: The layer (P1 layer) that has been processed to form protrusions

2: Reference surface in non-contact optical roughness measurement and AFM measurement (height 0nm)

3: Line with height of 1nm (R _1nm )

4: Line of height 10nm (R _10nm )

5: Line of height 60nm (R _60nm )

6: P2 layer

7: P3 layer

Figure 1 is a conceptual diagram showing R _1nm , R _10nm , and R _60nm measured by non-contact optical roughness measurement or AFM (Atomic Force Microscope).

Fig. 2 is a schematic view of one aspect of the two-layer structure of the biaxially aligned thermoplastic resin film of the present invention.

Fig. 3 is a schematic view of one aspect of the three-layer structure of the biaxially aligned thermoplastic resin film of the present invention.

Fig. 4 is a schematic view of one aspect of the heterogeneous 3-layer structure of the biaxially aligned thermoplastic resin film of the present invention.

Hereinafter, the present invention will be described in detail.

The invention relates to a biaxially aligned thermoplastic resin film. In the present invention, the term “thermoplastic resin” refers to a resin that exhibits plasticity when heated. Representative resins include, for example: polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene α, β-dicarboxylate, and P-hexahydro Polymers of stubble-based terephthalate, polymers from 1,4-cyclohexanedimethanol, poly-P-vinyloxybenzoate, polyarylate, polycarbonate, etc. and their copolymers Polyester resins with ester bonds in the main chain as represented by composites; and polyamide resins with amide bonds in the main chain as represented by nylon 6, nylon 66, nylon 610, nylon 12, and nylon 11 ; Polyolefins mainly composed of hydrocarbons as represented by polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethylpentene, polybutene, polyisobutylene, polystyrene, etc.; polyether Polyethers such as PES, PPO, PEEK, polyethylene oxide, polypropylene oxide, and polyoxymethylene; polyvinyl chloride, polyvinylidene chloride Halogenated polymers represented by ethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, etc.; and copolymers or modifications of polyphenylene sulfide (PPS), polysulfide and the like; polyimide resins, etc.

As the thermoplastic resin used in the present invention, polyester, polyolefin, polyphenylene sulfide (PPS), and polyimide (PI) are preferred from the viewpoints of transparency and film forming properties. Ingredients, especially polyester. The term "main component" as used herein refers to a component that contains more than 50% by mass and 100% by mass or less in 100% by mass of the total components of the film.

In addition, the polyester resin in the present invention refers to a polycondensation polymerization of a dicarboxylic acid component and a diol component. In addition, in this specification, the so-called constituent means the smallest unit that can be obtained by hydrolyzing polyester.

Examples of the dicarboxylic acid constituents constituting such polyester include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6- Aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, or their ester derivatives.

In addition, the diol constituents constituting the polyester include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1 Aliphatic diols such as ,3-butanediol; alicyclic diols such as cyclohexanedimethanol and spirodiol; plural linkers of the above diols, etc. Among them, from the viewpoint of mechanical properties and transparency, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalenedicarboxylic acid are suitable for use. Ester (PEN) and copolymerization of isophthalic acid or naphthalene dicarboxylic acid for part of the dicarboxylic acid component of PET, and cyclohexanedimethanol, spirodiol, diethylene glycol for part of the glycol component of PET Copolymerized polyester.

The biaxially aligned thermoplastic resin film of the present invention must be biaxially aligned. By carrying out biaxial alignment, the mechanical strength of the film can be improved and wrinkles are not prone to occur, and the rollability can be improved. The so-called dual-axis alignment here refers to the pattern that shows the dual-axis alignment when wide-angle X-rays are diffracted. Biaxially oriented thermoplastic resin film is generally not stretched The stretched thermoplastic resin sheet can be obtained by extending it in the longitudinal direction and the width direction of the sheet, and then performing heat treatment to complete the crystal alignment. The details will be described later.

In the biaxially oriented thermoplastic resin film of the present invention, on at least one surface, the number of protrusions of 10 nm or more measured by a non-contact optical roughness measuring device according to the method described below is defined as A (pieces/mm ² ) When the number of protrusions with a height of 1 nm or more and less than 10 nm measured by AFM (Atomic Force Microscope) is set to B (pieces/mm ² ), A must be 2.0×10 ³ or more and 2.5×10 ⁴ Below, and set as B (pieces/mm ² ), B is 1.8×10 ⁶ or more and 1.0×10 ⁷ or less (Hereinafter, A is sometimes 2.0×10 ³ or more and 2.5×10 ⁴ or less, and set as In the case of B (pieces/mm ² ), B is the film surface of 1.8×10 ⁶ or more and 1.0×10 ⁷ or less, which is simply referred to as the above surface).

The number A (number/mm ² ) of protrusions with a height of 10 nm or more measured by the non-contact optical roughness measuring device of the present invention reflects the number of protrusions responsible for air release during winding. As the number of protrusions A (pieces/mm ² ) increases, the contact area with other film surfaces (hereinafter, sometimes referred to as contact area) decreases and a space for air escape is ensured, so the windability improves. On the other hand, when the number of protrusions A (pieces/mm ² ) is too large, the number of higher protrusions may increase, which may cause more transfer defects. Also, when the number of protrusions A (pieces/mm ² ) is small, the contact area with other surfaces increases due to the flatness of the film, and the air release property deteriorates, regardless of the number of protrusions B (pieces/mm ² ) described later. In many cases, wrinkles caused by the air remaining in the film occur during film winding and the quality is reduced. The number A (pieces/mm ² ) of protrusions with a height of 10 nm or more is more preferably 3.0×10 ³ or more and 2.0×10 ⁴ or less, and still more preferably 4.0×10 ³ or more and 2.0×10 ⁴ or less.

In the present invention, the number of protrusions with a height of 1 nm or more and less than 10 nm measured by AFM (Atomic Force Microscope) is set to B (pieces/mm ² ), which reflects the presence of the surface layer on the surface The number of fine protrusions: By reducing the contact area between the surface layer part and other surfaces, and at the same time increasing the air escape channel due to the fine protrusion and concave structure, it can significantly promote the release of air from the above 10nm protrusions The effect of sex. In addition, because there are many protrusions with a height of 1 nm or more and less than 10 nm in the surface layer, the friction between the film or the process roll can be reduced, and the film surface damage can be reduced. When the number of protrusions B (pieces/mm ² ) is too large, the slipperiness of the film may increase, and the winding deviation may occur during the winding or the subsequent slitter step, and the winding condition of the roll may deteriorate. In addition, when the number of protrusions B (pieces/mm ² ) is small, the contact area with other surfaces increases due to the flatness of the film, and the air release performance deteriorates. The quality of wrinkles caused by air is reduced. The number B (number/mm ² ) of protrusions having a height of 1 nm or more and less than 10 nm is more preferably 3.0×10 ⁶ or more and 8.5×10 ⁶ or less.

In the conventional technique, as a method of increasing the number A (pieces/mm ² ) of protrusions with a height of 10 nm or more measured by a non-contact optical roughness measuring device, for example, a method containing particles with a larger particle size . In addition, as a method of increasing the number of protrusions B (number/mm ² ) having a height of 1 nm or more and less than 10 nm as measured by AFM (Atomic Force Microscope), for example, a method containing particles with a smaller particle size method. However, with this method, the particle size of the particles contained to increase the number of protrusions B is reduced, so the aggregation of the particles cannot be ignored. As a result, the protrusions become coarser and the number of protrusions B is reduced. The number B becomes a certain value or more. In the present invention, the number of protrusions A and B can be controlled within the above range by the method described later.

Furthermore, in the biaxially oriented thermoplastic resin film of the present invention, it is preferable that the number C (pieces/mm ² ) of protrusions with a height of 60 nm or more measured by a non-contact optical roughness measuring device on the surface is 90 or less. The number C (number/mm ² ) of protrusions with a height of 60 nm or more reflects the number of protrusions with a height that causes transfer defects. When the number of protrusions C (pieces/mm ² ) exceeds 90, more transfer defects will occur, and the smoothness of the surface opposite to the above-mentioned surface will decrease, so more noise will be generated when the film is used for magnetic tape. . The number of protrusions C (number/mm ² ) is more preferably 80 or less. The lower limit of the number of protrusions C (pieces/mm ² ) does not particularly exist, and 0 is best.

In the biaxially aligned thermoplastic resin film of the present invention, the method for setting the number A of protrusions with a height of 10 nm or more as measured by a non-contact optical roughness measuring device within the above range is not particularly limited, and particles containing The method or the method of containing a resin that is different from the main component of the film. From the viewpoint of forming uniform protrusions regardless of film forming conditions, it is preferable to contain particles, and to control the average particle diameter or content of the particles contained thereby.

The particles contained in the biaxially oriented thermoplastic resin film of the present invention are not particularly limited, and any one of inorganic particles and organic particles may be used, or two or more kinds of particles may be used in combination. As the inorganic particles, for example, calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, zinc sulfide, calcium phosphate, alumina (α alumina, β alumina, γ oxide Aluminum, delta alumina), mica, mica, titanium mica, diatomaceous earth, talc, clay, kaolinite, lithium fluoride, calcium fluoride, montmorillonite, zirconia, wet silica, dry silica , Colloidal silica, etc. Examples include organic particles, core-shell organic particles, and the like that have acrylic resins, styrene resins, silicone resins, polyimide resins, and the like as constituent components.

As the particle size of the above-mentioned particles, it is preferable that the average primary particle size obtained by the method described later is 10 nm or more and 300 nm or less. When the average primary particle size is less than 10 nm, the cohesive force of the particles increases to form coarse aggregates, which may exceed the range of the number A of protrusions. When the above average primary particle size exceeds 300 nm, the size of each protrusion formed may become larger, which may exceed the range of the number A of protrusions. shape. The preferred range of the average primary particle diameter of the particles is 15 nm or more and 200 nm or less.

The content of particles contained in the biaxially oriented thermoplastic resin film of the present invention is not particularly limited, but in order not to impair transparency, the content of particles is preferably 3.0% by mass or less relative to the entire film. If it exceeds 3.0% by mass, even if particles having an average primary particle size within a preferable range are used, the film is partially cloudy, and the haze value described later may deviate from the preferable range. It is more preferably 2.0% by mass or less, and still more preferably 1.0% by mass or less. In addition, by making the biaxially oriented thermoplastic resin film of the present invention into a laminated structure of two or more layers, and only the layer having the above-mentioned surface contains particles, the transparency is improved and the number of protrusions A is easy to set Is the target range. The content of particles in the layer having the surface is preferably 0.1 to 0.5% by mass relative to the entire layer having the surface.

In addition, in the biaxially oriented thermoplastic resin film of the present invention, from the viewpoint of further improving the rollability, it is preferable to make the biaxially oriented thermoplastic resin film of the present invention into three or more layers, and The outermost layer opposite to the layer with the above-mentioned surface contains particles. Regarding the types of particles contained, the same ones as the layer having the above-mentioned surface can be applied, but from the viewpoint of ensuring the transparency of the film, it is preferable that the average primary particle size is 10 nm or more and 100 nm or less. In addition, the content of particles contained in the outermost layer opposite to the above-mentioned surface is preferably 1.5% by mass or less with respect to the entire outermost layer. As a more preferable aspect, for example, with respect to the entire biaxially oriented thermoplastic resin film, the particle content is set to 3.0% by mass or less as described above, so that the layer having the above surface is on the opposite side of the layer having the above surface. A film in which the outermost layer contains particles, and the layer without the surface layer is substantially free of particles; if such a film is made, the transparency will be good.

On the surface of the biaxially oriented thermoplastic resin film of the present invention, the method for setting the number B of protrusions with a height of 1 nm or more and less than 10 nm measured by AFM in the above range is not particularly limited, and examples can be given For example: a method of transferring a shape to the surface using a mold like nanoimprinting; after plasma surface treatment of an unstretched sheet by atmospheric pressure glow discharge, the method of biaxial stretching described later is performed. From the viewpoint of film-forming adaptability on the production line or the number of micro-protrusions formed, it is more preferable to perform biaxial stretching after plasma treatment by atmospheric pressure glow discharge. The atmospheric pressure here refers to the range of 700 Torr to 780 Torr.

Atmospheric pressure glow discharge treatment is to introduce the thin film of the object to be processed between the opposing electrodes and the ground roller, introduce a plasma exciting gas into the device, and apply a high-frequency voltage between the electrodes, thereby causing the gas to generate plasma excitation. Glow discharge is performed between the electrodes. Generally speaking, when the surface of the thermoplastic resin film is treated by atmospheric pressure glow discharge treatment, the molecular chain on the surface of the film is cut or the low molecular weight gas generated by the plasma energy generated by the glow discharge The phenomenon that the surface of the film is cut (hereinafter sometimes referred to as decomposition and removal). As a result, the surface of the film is finely processed (decomposed and removed) to form protrusions.

The so-called plasma excitable gas refers to the gas that can be excited by plasma under the above-mentioned conditions. Examples of plasma-excitable gases include rare gases such as argon, helium, neon, krypton, and xenon; nitrogen, carbon dioxide, oxygen, or chlorofluorocarbons such as tetrafluoromethane, and mixtures thereof. In addition, the plasma excitation gas may be used singly, or two or more types may be used in combination according to any mixing ratio. From the viewpoint that the activity becomes higher when excited by the plasma, it is preferable to contain at least one of argon, oxygen, and carbon dioxide, and it is more preferable to contain oxygen. By using a plasma excitation gas with higher activity, there is a tendency to increase the height of the protrusions formed by promoting the decomposition and removal of the film surface, or the height of protrusions caused by the addition of particles. When the number A of protrusions with a height of 10 nm or more measured by a non-contact optical roughness measuring device increases.

The frequency of the high-frequency voltage during plasma processing is preferably in the range of 1 kHz to 100 kHz. In addition, from the viewpoint of protrusion formation, the discharge treatment intensity (E value) obtained by the following method is preferably 10~2000W. Min/m ² range for processing, preferably 40~500W. min/m ² . If the discharge treatment strength (E value) is too low, the protrusions may not be formed sufficiently. If the discharge treatment strength (E value) is too high, the thermoplastic resin film may be damaged or decomposed and removed without forming. Protruding situation.

<How to find the intensity of discharge treatment (E value)>

E=Vp×Ip/(S×Wt)

E: E value (W．min/m ² )

Vp: Applied voltage (V)

Ip: Applied current (A)

S: Processing speed (m/min)

Wt: Processing width (m).

Figure 1 shows a conceptual diagram of R _1nm , R _10nm , and R _60nm measured by a non-contact optical roughness measuring device and AFM. In Fig. 1, the so-called reference surface refers to a height where the distance between the measurement surface and the reference surface is defined as 0 (a positive value when it is higher than the reference surface, and a negative value when it is lower than the reference surface).

Generally speaking, when the surface of a thermoplastic resin film, especially a film with an amorphous part and a crystalline part like PET or PEN, is decomposed and removed by atmospheric pressure glow discharge treatment, the softer amorphous part will be decomposed and removed. . By subdividing the crystalline part and the amorphous part, the atmospheric pressure glow discharge treatment can form finer protrusions. Furthermore, by increasing the crystalline part in advance, the softer amorphous part is cut deeper. The height of the protrusion can be increased.

Therefore, the intrinsic viscosity (IV) of the layer having the above-mentioned surface of the thermoplastic resin film of the present invention is preferably 0.50 dL/g or more, more preferably 0.60 dL/g or more. The IV is a number reflecting the length of the molecular chain. The longer molecular chain is easier to clearly form the crystalline part and the amorphous part in the same molecular chain, so it is easier to form finer protrusions by atmospheric pressure glow discharge treatment, which is preferred. In addition, when the IV is less than 0.50 dL/g, since the molecular chain is short and crystallization is easy to proceed, breakage frequently occurs during the stretching step, and film formation may be difficult.

As a method of setting the number of protrusions A and B in the above-mentioned range on the above-mentioned surface of the biaxially oriented thermoplastic resin film of the present invention, for example, the layer having the above-mentioned surface contains the above-mentioned particles while performing plasma treatment. Perform biaxial extension. In addition, there is a tendency for the number of protrusions A described above to be increased by dispersing other thermoplastic resin components in the thermoplastic resin constituting the film in a nanometer level. In addition, if the intensity of the atmospheric pressure glow discharge treatment in the plasma treatment, or the activity of the plasma exciting gas used in the atmospheric pressure glow discharge treatment is increased, the number of protrusions B tends to increase.

The biaxially oriented thermoplastic resin film of the present invention may have a single-film structure or a structure in which two or more layers of other resins are laminated. In the case of a two-layer structure, when the layer having the above-mentioned surface is called the P1 layer and the laminated layer is called the P2 layer, it is preferable to arrange the P1 layer so that the protrusion surface of the P1 layer becomes the outermost P1 layer/ The composition of the P2 layer. In the case of a three-layer structure, it may be a two-type three-layer structure (P1 layer/P2 layer/P1 layer), or a heterogeneous three-layer structure (P1 layer/P2 layer/P3 layer) in which other resins are further laminated.

There are no particular restrictions on the method of laminating the P1 layer with other resin layers such as the P2 layer and the P3 layer. The co-extrusion method described later can be used, or other resin layers Raw materials are fed into an extruder, melted, extruded from a die, and laminated to a film on the way of film formation (melt lamination method). The film after film formation is laminated with each other through an adhesive layer. Among them, it is preferable to use a co-extrusion method for forming protrusions and lamination that can simultaneously perform the above-mentioned processing.

The structure of the P2 layer and the P3 layer of the biaxially oriented thermoplastic resin film of the present invention is not particularly limited, but from the viewpoint of ensuring the transparency of the film, it is preferable that it contains substantially no particles. The term "substantially free of particles" means that the content of particles relative to the thermoplastic resin film is 500 ppm or less, more preferably 50 ppm or less, and most preferably 10 ppm or less. In addition, in the range that does not impair the effects of the present invention, heat-resistant stabilizers, oxidation-resistant stabilizers, antistatic agents, organic/inorganic slip agents, nucleating agents, etc. can also be blended in the P1, P2, and P3 layers. Additives such as dyes, dispersants, coupling agents, wavelength conversion materials, etc.

When the thermoplastic resin film of the present invention is used in applications requiring high light transmittance, such as a dry film photoresist support film, the haze of the film is preferably 0.60% or less. When the haze exceeds 0.60%, the penetrating light will be scattered when the film is used, and the photoresist wiring will be disadvantageous in applications such as dry film photoresist support. More preferably, it is 0.50% or less, more preferably 0.45% or less.

Next, the method for manufacturing the biaxially oriented thermoplastic resin film of the present invention will be described by taking a biaxially oriented polyester film as an example, but the present invention should not be construed as being limited to the products obtained from this example.

As a method for obtaining the polyester used in the present invention, a polymerization method carried out according to a conventional method can be adopted. For example, a dicarboxylic acid component such as terephthalic acid or an ester-forming derivative thereof, and a glycol component such as ethylene glycol or an ester-forming derivative thereof are subjected to a transesterification reaction or an esterification reaction by a known method, It can be obtained by melt polymerization. In addition, if necessary, the polyester obtained by melt polymerization can be lower than the melting temperature of the polyester Carry out solid-phase polymerization.

The biaxially oriented thermoplastic resin film of the present invention can be obtained according to conventionally known manufacturing methods. Specifically, the biaxially oriented thermoplastic resin film of the present invention can be processed into a sheet by heating and melting the dried raw material in an extruder, and extruding it from the die to the cooled casting drum. Shape method (melt casting method). As another method, it is possible to dissolve the raw material in a solvent, extrude the solution from the die onto a support such as a casting drum or an endless belt to form a film, and then dry and remove the solvent from the film to be processed into a sheet Material-like method (solution casting method), etc.

When manufacturing two-layer or more laminated polyester resin film by melt casting method, it is suitable to use each layer according to the composition of the laminated polyester film, use an extruder to melt the raw materials of each layer, and set these in the extrusion device and die. The merging device between the layers is laminated in the molten state, guided to the die, and then extruded from the die to the casting drum to be processed into a sheet (co-extrusion method). The laminated sheet is statically attached to a roller whose surface temperature is cooled to 20°C or more and 60°C or less, and then cooled and solidified to produce an unstretched sheet. The temperature of the casting drum is more preferably 25°C or more and 60°C or less, still more preferably 30°C or more and 55°C or less. When the temperature is below 20°C, there may be insufficient formation of protrusions on the surface of the film after irradiated with plasma and biaxially stretched. If it exceeds 60°C, the film may stick to the casting roll and it may be difficult to obtain an unstretched film.

Next, the unstretched film thus obtained is subjected to surface treatment such as plasma treatment of atmospheric pressure glow discharge. These surface treatments can be performed immediately after the unstretched film is obtained, or after micro-stretching, or after stretching in the longitudinal and/or transverse directions. In the present invention, it is preferable to perform surface treatment on the unstretched film. deal with. In addition, the surface to be subjected to the surface treatment may be either a surface contacting the casting drum (roller surface) or a surface not contacting the casting drum (non-roller surface).

Thereafter, the unstretched film is biaxially stretched to be biaxially aligned. As the stretching method, a successive biaxial stretching method or a synchronized biaxial stretching method can be used. The sequential biaxial stretching method, which initially stretches in the longitudinal direction and then stretches in the width direction, can effectively obtain the biaxially aligned thermoplastic resin film of the present invention without stretching fracture.

(Biaxial extension)

There are no particular restrictions on the stretching conditions when biaxially stretching the unstretched film. When the biaxially oriented thermoplastic resin film of the present invention is made of polyester as the main component, it is preferable to stretch the unstretched film in the longitudinal direction. The stretched sheet is guided to a group of rollers heated above 70°C, stretches in the longitudinal direction (longitudinal direction, that is, the direction of travel of the sheet), and is cooled by a group of rollers at a temperature of 20-50°C. The lower limit of the temperature of the heating roller during stretching in the longitudinal direction is not particularly limited without impairing the extensibility of the sheet, and preferably exceeds the glass transition temperature of the polyester resin used. In addition, the preferred range of the stretching ratio in the longitudinal direction is 3 to 5 times. The more preferable range is 3 times to 4 times. If the stretching ratio in the longitudinal direction is less than 3 times, the orientation crystallization does not proceed and the film strength is significantly reduced. On the other hand, when the stretching ratio exceeds 5 times, the orientation crystallization of the polyester resin accompanying the stretching progresses, and the film may be broken while becoming brittle.

Next, regarding the extension in the direction perpendicular to the longitudinal direction (width direction), the two ends of the film are held by a clamp and guided to the stretcher, heated to a temperature of 70 to 160 ℃, facing the long side The direction is at right angles (width direction) to extend 3~5 times, and then heat the stretched film to stabilize the molecular alignment structure inside the film. Regarding the thermal history temperature of the film during heat treatment, it can be displayed directly below the melting point temperature measured by the differential scanning calorimeter (DSC) described later The temperature of the micro endothermic peak (hereinafter sometimes referred to as Tmeta) is confirmed. As the set temperature of the stretcher device, for example, when polyester (melting point 255℃) is the main component, it is better to set the highest temperature in the stretcher The temperature is set to 200°C or more and 250°C or less; when other thermoplastic resins are used as the main component, it is preferably set to a resin melting point of -55°C or more and a resin melting point of -5°C or less. In the case where the heat treatment temperature is less than 200°C, the protrusions formed by the above-mentioned atmospheric pressure glow discharge treatment cannot grow sufficiently, as a result, it is difficult to form the protrusions in the above-mentioned preferred range. On the other hand, when the heat treatment is performed at a temperature exceeding 250°C, the film melts and breaks in many cases and productivity is reduced. A more preferable range is 220°C or higher and 245°C or lower.

The range of Tmeta representing the heat history temperature received by the film during the heat treatment is preferably 190°C or higher and 245°C or lower when polyester is the main component. A more preferable range is 210°C or higher and 240°C or lower.

Furthermore, after the heat treatment, for the purpose of imparting dimensional stability, a relaxation (relaxation) treatment may be performed in the range of 0% or more and 6% or less.

The stretch magnification is set to 3 to 5 times in the longitudinal direction and the width direction, respectively, and the area magnification (longitudinal stretch magnification×lateral stretch magnification) is preferably 9 to 22 times, more preferably 9 to 20 times. If the area magnification is less than 9 times, the durability of the obtained biaxially stretched sheet is insufficient; if the area magnification exceeds 22 times, cracks tend to occur during stretching.

[Characteristic evaluation method]

A. Evaluation by non-contact optical roughness tester

(i) The number of protrusions with a height of 10nm or more A (pieces/mm ² )

A sample of 10cm×10cm is taken from the biaxially aligned thermoplastic resin film of the present invention. For each sample, a non-contact optical roughness measuring device (device: New View 7300 manufactured by Zygo Corporation) is used to measure the area using a 50-fold lens 139μm×104μm, random change of location, 80 field of view measurement. The sample setting is to set the sample on the table in such a way that the Y-axis of the measurement becomes the long side direction of the sample film (the so-called long side direction refers to the direction in which the film progresses in the film manufacturing step). For the obtained measurement data, the cut-off value is set to 1.65μm in High Filter Wavelen and 50.00μm in Low Filter Wavelen with the surface analysis software Metro Pro 8.1.3 installed in the roughness tester. The Reference Band (bandwidth) is designated as 100nm, and the peak in the cut level of 10nm is converted into units/mm ² unit. The same operation was performed in all 80 fields of view, and the average value thereof was used as the number A (number/mm ² ) of protrusions with a height of 10 nm or more in the present invention.

(ii) The number C of protrusions above 60nm in height (pcs/mm ² )

In the same manner as in the preceding paragraph (i), the peaks in the cut level of 60 nm are converted into units/mm ² and the average value of the observed 80 fields of view is taken as the number C of protrusions with a height of 60 nm or more in the present invention.

B. Evaluation by AFM (Atomic Force Microscope)

(iii) The number B of protrusions with a height of 1 nm or more and less than 10 nm (pieces/mm ² )

Use the attached analysis software (NanoScope Analysis Version 1.40) to analyze the image of the film surface obtained by the following measurement method. After only performing the following Flatten processing on the height sensor image of the obtained film surface, the Particle Analysis analysis mode is set as follows, and the reference plane of the film surface is automatically determined. From this reference plane, the average value of the protrusion density per 1μm ² when the threshold height of the protrusion (Threshold Height) is 1nm (R _1nm ) (the value in the Density column, Mean row) is converted to the value per 1mm ² as N _1nm (pieces/mm ² ), the average value of the protrusion density per 1μm ² at 10nm (R _10nm ) (Density column, Mean row value) is converted to a value per 1mm ² as N _10nm (pieces/mm ² In the case of ), the value obtained by the following formula is regarded as the number B (number/mm ² ) of protrusions with a height of 1 nm or more and less than 10 nm of the measured image.

B (pieces/mm ² )=N _1nm (pieces/mm ² )-N _10nm (pieces/mm ² )

Perform the above analysis on all 20 measurement images of each sample, and use the average value as the number of protrusions B (pieces/mm ² ) with a height of 1 nm or more and less than 10 nm of the sample

[AFM measurement method]

˙Device: Atomic Force Microscope (AFM) Dimention Icon with ScanAsyst manufactured by Bruker

˙Cantilever: silicon nitride probe ScanAsyst Air

˙Scan mode: ScanAsyst

˙Scanning speed: 0.977Hz

˙Scan direction: scan toward the width direction of the measurement sample made according to the method described below

˙Measurement field of view: 5μm square

˙Sample pipeline 512

˙Peak Force SetPoint: 0.0195V~0.0205V

˙Feedback Gain: 10~20

˙LP Deflection BW: 40kHz

˙ScanAsyst Noise Threshold: 0.5nm

˙Sample adjustment: 23℃, 65%RH, stand for 24 hours

˙AFM measurement environment: 23℃, 65%RH

˙Method of preparing the measurement sample: Attach it on one side of the AFM sample disc (diameter 15mm) Double-sided tape, the AFM sample disc and the biaxially oriented thermoplastic resin film of the present invention cut out to about 15mm×13mm (long side direction×width direction) are pasted on the opposite side of the above-mentioned surface (measurement surface) as Measure the sample.

˙Number of sample measurements: Change the location so that each sample is at least 5μm away from each other, and perform 20 measurements.

˙Measured value: Perform the above analysis on the measured 20 images, measure each value and use the average value as the value of the sample.

[Flatten processing]

˙Flatten Order: 3 ^rd

˙Flatten Z Threshholding Direction: No thresholding

˙Find Threshold for: the whole image

˙Flatten Z Threshold %: 0.00%

˙Mark Excluded Data: Yes

[Particle Analysis mode setting]

(Detect tab)

˙Threshold Height: cooperate with each value input

˙Feature Direction: Above

˙X Axis: Absolute

˙Number Histogram Bins: 512

˙Histogram Filter Cutoff: 0.00nm

˙Min Peak to Peak: 1.00nm

˙Left Peak Cutoff: 0.00000%

˙Right Peak Cutoff: 0.00000%

(Modify tab)

˙Beughbirhood Size: 3

˙Number Pixels off: 1

˙All Dilate/Erode operations are not performed.

(Select tab)

˙Image Cursor Mode: Particle Select

˙Bound Particles: Yes

˙Non-Representative Particles: No

˙Height Reference: Relative To Max Peak

˙Number Histogram Bins: 50

˙When calculating the above values, do not choose to analyze specific peaks and regions in the image

˙No specific place is selected for all histograms of Diameter, Height, and Area.

C. Average primary particle size

The cross-section of the biaxially aligned thermoplastic resin film of the present invention was observed at 10,000 times using a transmission electron microscope (TEM). At this time, when particles of 200 nm or less were confirmed in the observation field, the TEM observation magnification was changed to 100,000 times for observation. Change the location to measure the 100 field of view, and convert the equivalent circle diameter of all the scattered particles taken in the photo. Use the horizontal diameter as the equivalent circle diameter and the vertical axis as the number of particles to describe the particle number distribution, and divide the wave peak value The equivalent circle diameter is taken as the average primary particle size of the particles. Here, the above drawing does not include the case where agglomerated particles are confirmed on the photograph observed at 10,000 times. When there are two or more types of particles with different particle diameters in the film, the number distribution of the equivalent circle diameter is a distribution having two or more peaks. At this time, the respective peaks are regarded as the average primary particle size of the respective particles. The particle size of the largest particle is the particle size of the particle with the largest particle size in the photograph observed at 10,000 times.

The average primary particle size of agglomerated particles was observed at 200,000 times using the above-mentioned device. For 100 agglomerated particles, the equivalent circle diameter of each primary particle constituting the agglomerated particle is converted and drawn in the same way as above, and the equivalent circle diameter of the peak value is taken as the average primary particle diameter of the agglomerated particle.

D. Particle content

1 g of the P1 layer part of the biaxially oriented thermoplastic resin film of the present invention was put into 200 mL of 1N-KOH methanol solution and heated to reflux to dissolve the polymer. 200 mL of water was added to the solution after dissolution, and then the liquid was centrifuged to settle the particles, and the supernatant was removed. Further wash the particles with water, centrifuge and repeat 2 times. The particles thus obtained are dried, and the mass is weighed to calculate the particle content.

E. Air release index

The DIGI-BEKK smoothness tester (Toyo Seiki Co., Ltd.) was used to measure at 25°C and 65% RH. The biaxially aligned thermoplastic resin film of the present invention is arranged in such a way that the surface having the above-mentioned surface is in contact with the sample table. At this time, it is set so that the film completely covers the cavity on the sample table. Apply a load of 1kg/cm ^{2 in} this state, and set the initial decompression degree (the decompression degree from normal pressure) to 385mmHg. Since the normal pressure is decompressed to 385mmHg to return to normal pressure, air flows between the film and the sample stage. At this time, the time (air release time) from 382mmHg to 381mmHg from normal pressure is measured. The above-mentioned air release time was measured for 10 samples, and the average value was used as the air release index of the film.

A: The air release time is less than 2400 seconds

B: The air release time is more than 2400 seconds and less than 2700 seconds

C: The air release time is more than 2700 seconds and less than 2900 seconds

D: Air release time is more than 2900 seconds

The air release index is good from A to C, and the best is A.

F. The inherent viscosity of the film

The film of the present invention was dissolved in 100 ml of o-chlorophenol (solution concentration C=1.2g/dL), and the 25°C viscosity of the solution was measured using an Austen Viscometer. Also, the viscosity of the solvent was measured in the same manner. Using the obtained solution viscosity and solvent viscosity, [η] (dL/g) is calculated by the following formula (a), and the obtained value is taken as the intrinsic viscosity (IV).

(a) ηsp/C=[η]+K[η] ² . C

(Here, ηsp=(solution viscosity (dL/g)/solvent viscosity (dL/g))-1, K is the Herkins constant (set to 0.343)).

When the biaxially oriented thermoplastic resin film of the present invention has a laminated structure, only the P1 layer is cut out of the IV system of the layer (P1 layer) having the above-mentioned surface by a conventional method, and the measurement is performed according to the above method.

G. The amount of terminal carboxyl groups (indicated as COOH amount in the table)

The amount of terminal carboxyl groups was measured in accordance with Maulice's method according to the following method. (Document M.J.Maulice, F.Huizinga, Anal.Chim.Acta, 22 363 (1960))

Dissolve 2 g of the measurement sample in 50 mL of o-cresol/chlorine (weight ratio 7/3) at a temperature of 80°C, and titrate with a 0.05N KOH/methanol solution to determine the concentration of terminal carboxyl groups. Value representation. In addition, phenol red is used as an indicator for titration, and the end point of the titration is when it changes from yellow-green to light red. In addition, when there are insoluble matter such as inorganic particles in the solution in which the measurement sample is dissolved, the solution is filtered and the insoluble matter is removed. For mass measurement, a calibration is performed by subtracting the mass of the insoluble matter from the mass of the measurement sample as the mass of the measurement sample.

H. Coilability

The biaxially oriented thermoplastic resin film of the present invention was formed into a film with a width of 4.5 m and was continuously wound with a roll of 5000 m for 10 times, and the film rollability was evaluated as follows in the case of the obtained 10 rolls.

A: Within 10 rolls, the number of rolls with wrinkles is less than 1 roll.

B: Among 10 rolls, 2 rolls have wrinkles.

C: Among 10 rolls, the number of rolls with wrinkles is 3 or more and 4 or less.

D: Among 10 rolls, the number of rolls with wrinkles is 5 or more and 6 or less.

E: Among 10 rolls, there are 7 or more rolls with wrinkles.

The coilability is good from A to D, and the best is A.

I. Winding situation

Regarding the 10 biaxially oriented thermoplastic resin film rolls of the present invention used in the previous paragraph, 30 rolls were cut into strips with a width of 1.5m each. From the condition of the strip roll, the winding condition of the film roll was evaluated as follows.

A: Among 30 rolls, the number of rolls with winding deviation is 2 or less.

B: Among 30 rolls, the number of rolls with winding deviation is 3 or more and 5 or less.

C: Among 30 rolls, the number of rolls with winding deviation is 6 or more and 8 or less.

D: Among 30 rolls, there are 9 or more rolls with winding deviation.

J. Evaluation of shortcomings of shape transfer

The evaluation of the defect of the shape transfer of the biaxially oriented thermoplastic resin film of the present invention was evaluated according to the following method. The biaxially oriented thermoplastic resin film of the present invention cut to a width of 1 m is conveyed under a tension of 200N. On the side of the biaxially oriented thermoplastic resin film of the present invention opposite to the above surface, the non-magnetic layer described later is used for forming The coating liquid and the coating liquid for forming a magnetic layer are coated in a double layer, and the coating liquid for forming a back coat layer described later is applied to the surface side, and then cut into strips with a width of 12.65 mm (1/2 inch) to make a pancake ( pancake).

(Hereinafter, "parts" means "parts by mass".)

For each of the above-mentioned coating liquids, the respective components were kneaded with a kneader. In a horizontal sand mill equipped with 1.0mmΦ zirconia balls filled with an amount of 65% by volume relative to the volume of the dispersion part, the coating liquid was passed through a pump and carried out at 2,000rpm for 120 minutes (essentially The time spent in the dispersion part) is dispersed. For the coating of the non-magnetic layer, add 5.0 parts of polyisocyanate to the obtained dispersion, and for the coating of the magnetic layer, add 2.5 parts, and further add 3 parts of methyl ethyl ketone, using a filter with a 1μm average pore size. After filtering, the coating solutions for forming the non-magnetic layer and the coating solution for forming the magnetic layer were prepared separately.

The obtained coating solution for forming a non-magnetic layer is applied to the surface of the biaxially oriented thermoplastic resin film of the present invention opposite to the above-mentioned surface, and the thickness after drying becomes After coating and drying by 0.8μm method, apply the coating solution for forming the magnetic layer so that the thickness of the magnetic layer after drying becomes 0.07μm. When the magnetic layer is still wet, use a 6,000G (600mT) The magnetic cobalt magnet and the solenoid with 6,000G (600mT) magnetic force are aligned and dried.

Thereafter, the coating solution for forming a back coat layer was applied to the surface side so that the thickness after calendering became 0.5 μm (the average particle size of carbon black was 17 nm: 100 parts, and the average particle size of calcium carbonate was 40 nm: 80 parts. , And α alumina average particle size 200nm: 5 parts, dispersed in polyurethane resin, polyisocyanate). Next, after calendering at a temperature of 90°C and a line pressure of 300kg/cm (294kN/m) using a calender, curing was performed at 65°C for 72 hours. In addition, a non-woven fabric and a razor are installed on a device with a device for discharging and reeling strips by pressing against the magnetic surface, and the surface of the magnetic layer is cleaned by the tape cleaning device to obtain a magnetic tape.

The obtained tape material was cut into strips with a width of 12.65 mm (1/2 inch), and assembled in a box for LTO to form a data storage cassette with a magnetic recording tape length of 960 m. This data storage cartridge was used for recording in an environment of 23°C and 50% RH using an LTO7 driver manufactured by IBM (recording wavelength 0.55 μm), and then the cartridge was stored at 50°C and 80% RH for 7 days. After the cassette was stored at room temperature for 1 day, full-length playback was performed, and the signal error rate during playback was measured. The error rate is calculated by the error information (number of error bits) output by the driver according to the following formula (b).

(a) Error rate = (number of error bits)/(number of written bits)

A: The error rate is less than 1.0×10 ^-6 .

B: The error rate is 1.0×10 ^-6 or more and less than 1.0×10 ^-5 .

C: The error rate is 1.0×10 ^-5 or more and less than 1.0×10 ^-4 .

D: The error rate is 1.0×10 ^-4 or more.

The shape transfer defect evaluation is based on A~C as good, and the best is A.

K. Evaluation of characteristics of embryonic tablets

The following methods a. to b. are used to evaluate the characteristics of the green sheet.

a. Coating of release layer

On the surface of the biaxially oriented thermoplastic resin film of the present invention opposite to the above-mentioned surface, the cross-linked primer layer (trade name BY24-846 manufactured by Toray, Dow Corning, Silicones (stock)) is adjusted to a solid content of 1% by mass The coating solution is coated/dried, and then coated with a gravure coater so that the coating thickness after drying becomes 0.1μm, and then dried and cured at 100°C for 20 seconds. Thereafter, within 1 hour, 100 parts by mass of addition reaction type silicone resin (Toray Dow Corning Silicones (stock) product name LTC750A), platinum catalyst (Toray Dow Corning Silicones (stock) product product Name SRX212) 2 parts by mass of a coating solution adjusted to a solid content of 5% by mass. After drying, the coating thickness becomes 0.1μm, and then apply it with a gravure coater. After drying and curing at 120°C for 30 seconds Reel to obtain release film.

b. Evaluation of the coating state of the green sheet (coating property of ceramic slurry)

Based on 100 parts by mass of barium titanate (trade name HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.), 10 parts by mass of polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.), and 5 mass parts of dibutyl phthalate Toluene-ethanol (mass ratio 30:30) 60 parts by mass, add glass beads with a number average particle size of 2mm, and mix with a jet mill for 20 hours. After the dispersion, filtration is performed to prepare a paste-like ceramic slurry. The resulting ceramic slurry was coated with a die coater on the surface of the release film with the release layer provided in the previous paragraph a, and dried so that the thickness after drying became 2μm, and then rolled to obtain a green sheet . Take out the rolled up green sheet, and visually observe whether there are pinholes or sheet material in a state where it is not peeled off from the release film Coating state of surface and end. In addition, the observed area is 300mm wide and 500mm long. For the green sheet formed on the release film, irradiate it from the back with a 1000 lux backlight unit, and observe the pinholes caused by missing coating, or the concave state on the back of the release film caused by surface transfer.

A: No pinholes and no dents.

B: There is no pinhole, and the number of depressions is less than 3.

C: There is no pinhole, and the number of depressions is less than 5.

D: There are pinholes in a part, or 6 or more dents.

The evaluation system of green sheet characteristics is good from A to C, and A is the best.

L. Haze

From the biaxially oriented thermoplastic resin film of the present invention, 3 pieces (3 pieces) of square samples with a side of 5 cm are collected. The sample was then placed at 23°C and 60%RH for 40 hours. The turbidity meter "NDH5000" manufactured by Nippon Denshoku Industries Co., Ltd. was used for each sample, and it was implemented in accordance with the JIS "Method of Obtaining Haze of Transparent Materials" (K7136 2000 Edition). The haze value of each 3 pieces (3 pieces) is averaged, and it is set as the haze value of a film.

M. Photoresist evaluation

Use the following methods a. to c. for photoresist evaluation.

a. Coat the negative photoresist "PMERN-HC600" manufactured by Tokyo Ohka Co., Ltd. on a single-sided mirror-polished 6-inch Si wafer, and spin it with a large spin coater to produce a photoresist with a thickness of 7μm Floor. Then, using a ventilated furnace with nitrogen circulation, the pre-heat treatment is performed for about 20 minutes at a temperature of 70°C.

b. The biaxially aligned thermoplastic resin film of the present invention is opposite to the above-mentioned surface The surface is overlapped in the way that it touches the photoresist layer. Using a rubber roller, a biaxially oriented thermoplastic resin film is laminated on the photoresist layer, and a grating patterned by chromium metal is placed on the photomask. An I-ray (ultraviolet with a sharp peak at a wavelength of 365 nm) stepper was used for exposure.

c. After peeling off the polyester film from the photoresist layer, put the photoresist layer in a container with developer N-A5 for development for about 1 minute. After that, it was taken out of the developing solution and washed with water for about 1 minute. Use scanning electron microscope SEM to observe the state of L/S(μm)(Line and Space)=10/10μm of 30 strips of the photoresist pattern made after development at a magnification of about 800~3000. According to the defective strips in the pattern The number is evaluated as follows.

A: The number of defective bars is less than 5

B: The number of defective bars is 6 or more and 10 or less

C: The number of defective bars is 11 or more and 15 or less

D: The number of defective bars is 16 or more

The evaluation of photoresist properties is based on A to C as good, and the best is A.

[Example]

Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to these.

[Production of PET-1] From terephthalic acid and ethylene glycol, using antimony trioxide as a catalyst, polymerization is carried out according to the usual method to obtain substantially no particles of melt polymerized PET. The obtained melt polymerized PET has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.62. Thereafter, solid-phase polymerization was carried out according to the usual method to obtain solid-phase polymerized PET. The obtained solid-phase polymerized PET has a glass transition temperature of 81°C, a melting point of 255°C, and an inherent viscosity of 0.81.

[Manufacturing of MB-A] During the polymerization of PET-1 in the preceding paragraph, the With the content of 2.0% by weight, δ alumina (alumina-1) with an average primary particle size of 21nm dispersed in ethylene glycol was added to obtain the PET base masterbatch MB-A. The obtained melt polymerized MB-A has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-B] During the polymerization of PET-1 in the preceding paragraph, δ alumina (alumina-alumina) dispersed in ethylene glycol with an average primary particle size of 16 nm was added so that the content of PET was 2.0% by weight. 2) Obtain the PET base masterbatch MB-B. The obtained melt polymerized MB-B had a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-C] During the polymerization of PET-1 in the preceding paragraph, δ alumina (alumina-alumina) dispersed in ethylene glycol with an average primary particle size of 11 nm was added so that the content of PET was 2.0% by weight. 3) Obtain the PET base masterbatch MB-C. The obtained melt polymerized MB-C has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-D] During the polymerization of PET-1 in the preceding paragraph, silica (silica dioxide) with an average primary particle size of 210nm dispersed in ethylene glycol was added to 2.0% by weight relative to the content of PET. -1) to obtain the PET base masterbatch MB-D. The obtained melt polymerization MB-D has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-E] During the polymerization of PET-1 in the preceding paragraph, silica (silica dioxide) with an average primary particle size of 265 nm dispersed in ethylene glycol was added at 2.0% by weight relative to the content of PET. -2) to obtain the PET base masterbatch MB-E. The obtained melt polymerization MB-E has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-F] During the polymerization of PET-1 in the preceding paragraph, silica (silica dioxide) with an average primary particle diameter of 320nm dispersed in ethylene glycol was added to 2.0% by weight relative to the content of PET. -3) to obtain the PET base masterbatch MB-F. The obtained melt polymerized MB-F has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-G] During the polymerization of PET-1 in the preceding paragraph, silica (silica dioxide) dispersed in ethylene glycol with an average primary particle size of 72nm was added at 2.0% by weight relative to the content of PET. -4) to obtain the PET base masterbatch MB-G. The obtained melt polymerized MB-G had a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-H] During the polymerization of PET-1 in the preceding paragraph, silica (silica dioxide) with an average primary particle size of 370 nm dispersed in ethylene glycol was added at 2.0% by weight relative to the content of PET. -5) to obtain the PET base masterbatch MB-H. The obtained melt polymerized MB-H has a glass transition temperature of 81°C, a melting point of 255°C, and an intrinsic viscosity of 0.70.

[Manufacturing of MB-I] The content of PET-1 and sodium stearate (crystal nucleating agent-1) in the preceding paragraph is 5.0% by weight based on the content of sodium stearate (crystal nucleating agent-1) relative to the PET-1 in the preceding paragraph The method carries out biaxial kneading and extrusion to obtain the PET base masterbatch MB-I. The obtained melt polymerized MB-I has a glass transition temperature of 83°C, a melting point of 255°C, and an intrinsic viscosity of 0.65.

(Example 1)

After the PET-1 and MB-A masterbatch were dried under semi-reduced pressure at 180°C for 2 hours, they were blended so that the particle concentration would become the amount of the P1 layer and the P2 layer described in Table 1, and then supplied to each extrusion After melt-extrusion and filtering with a filter, in the feed zone, the layers merge with the P1 layer/P2 layer, and then wind it at 37°C through a T-die casting method that can be applied with static electricity. It was placed on a cooling roll and cooled to solidify to obtain an unstretched film. The unstretched film is introduced between the opposite electrode and the grounding roller, and nitrogen is introduced into the device, and the E value becomes 160W. Under the condition of min/m ² , atmospheric pressure glow discharge treatment is performed.

The unstretched film after the treatment was stretched 3.6 times in the longitudinal direction, 4.0 times in the width direction, and 14.4 times in total by using a sequential biaxial stretching machine under the conditions described in Tables 1 and 2. Heat treatment at 240°C. Thereafter, relaxation treatment was performed in the width direction to obtain a biaxially aligned film with a thickness of 4.5 μm. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4. It is a film with good reelability, winding condition, and transfer defects.

(Examples 2~4)

In Examples 2 to 4, the same procedure as in Example 1 was carried out except that the used master particles were changed to the particle content concentration described in Table 1 to obtain a biaxially oriented film with a thickness of 4.5 μm. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

Example 2 added a large amount of particles with a larger diameter and an average primary particle size of 250 nm than that of Example 1. As a result, the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement increased, so the transfer defect Although it is lower than Example 1, it is still in a practical range, and it is a film with good windability and winding deviation.

Examples 3 and 4 used particles with an average primary particle size of 15nm and 10nm with a smaller diameter than that of Example 1. The results were measured by non-contact optical roughness measurement The number of protrusions with a height of 10nm or more decreases, and the coilability is worse than that of Example 1, or the number of protrusions with a height of 1nm or more and less than 10nm as measured by AFM increases, and the winding condition is more effective due to the winding deviation Example 1 deteriorated, but it was still in the practical range and was a film with good transfer defects.

(Example 5)

In Example 5, except for the atmospheric pressure glow discharge treatment as shown in Table 2, the E value is 450W. Except for the conditions of min/m ² , the same procedure as in Example 1 was carried out to obtain a biaxially oriented film with a thickness of 4.5 μm. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

Example 5 is a comparison of Example 1. The number of protrusions with a height of 1 nm or more and less than 10 nm as measured by AFM has increased. Although the winding condition is deteriorated due to winding deviation, it is still within the practical range and is a roll A film with good pick-up and transfer defects.

(Examples 6, 7)

Examples 6 and 7 were performed in the same manner as in Example 1, except that the used master particles were changed to the particle concentration described in Table 1 and the atmospheric pressure glow discharge treatment was changed as in Table 2 to obtain a thickness of 4.5 μm. Biaxial alignment film. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

In Examples 6 and 7, the number of protrusions with a height of 1 nm or more and less than 10 nm measured by AFM was reduced compared to Example 1. In Example 6, the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement was the same as that in Example 1, and the coilability was within the scope of implementation but worse than Example 1. On the other hand, in Example 7, the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement increased compared with that in Example 1, so the winding The performance is as good as Example 1, but the transfer defect is within the practical range but worse than Example 1.

(Examples 8, 9)

Examples 8 and 9 were performed in the same manner as in Example 1, except that the used master particles were changed to the particle addition concentration described in Table 1, to obtain a biaxially aligned film with a thickness of 4.5 μm. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

In both Examples 8 and 9, the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement and the number of protrusions with a height of 1 nm or more and less than 10 nm measured by AFM are preferable ranges, but due to the use For the larger particles of 200 nm and 300 nm, the number of protrusions with a height of 60 nm or more measured by non-contact optical roughness measurement is greater than that of Example 1. As a result, although the transfer disadvantages of Examples 8 and 9 were worse than those of Example 1, they were still in the practical range and were films with good windability.

(Example 10)

Except for the use of a gas mixed with 0.5% by volume of oxygen in nitrogen as the gas used in the atmospheric pressure glow discharge treatment, the remaining biaxial alignment film was obtained in the same manner as in Example 3. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Table 3 and Table 4.

Since Example 10 uses a plasma excitable gas with high activity, the size of the protrusions from the added particles becomes larger and the number of protrusions A is also larger than that of Example 3. It is a film with good rollability and transfer defects .

(Example 11)

Except for setting the film thickness to 25 μm, a biaxial alignment film was obtained in the same manner as in Example 1. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Table 3 and Table 4. Example 11 is a film that is equivalent to Example 1 and has good winding properties, winding conditions, and transfer defects.

The film of Example 11 was evaluated for green sheet and photoresist according to the above methods. Although the haze was slightly increased compared with Example 1 due to the increase in film thickness, the results were good as shown in Table 5 and Table 6. It is suitable for use as a dry film photoresist support film or a green sheet forming support film.

(Example 12)

Except that three types of extruders are used to extrude each layer according to the formula described in Table 1, and the layers are laminated in a different three-layer structure of P1 layer/P2 layer/P3 layer to make the film thickness 25μm, the rest follow the example 1 The same method is used to obtain a biaxial alignment film. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Table 3 and Table 4. Example 12 is a film with the same winding conditions and good transfer defects as those of Example 1. Furthermore, by placing the P3 layer containing particles on the outermost surface opposite to the above-mentioned surface, the winding performance is better than that of the example. 1 Better film.

The film of Example 12 was subjected to the evaluation of the green sheet and the photoresist according to the above methods. As a result, the P3 layer containing particles was provided. Although the haze was increased and the photoresist evaluation was lower than that of Example 11, it was still within the practical range and suitable Use as a dry film photoresist support film or a green sheet forming support film.

(Comparative example 1)

Except that the unstretched film was obtained by the same method as in Example 1, and was introduced into the sequential biaxial stretching machine without atmospheric glow discharge treatment, the other biaxially aligned film was obtained in the same way as in Example 1. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

Since the atmospheric pressure glow discharge treatment was not performed, the number of protrusions having a height of 1 nm or more and less than 10 nm measured by AFM was greatly reduced, and the result was a film with greatly deteriorated windability.

(Comparative example 2)

Except that the P1 layer is substantially free of particles, the other is the same method as in Example 1 to obtain a biaxially aligned film. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

Since no particles are added, protrusions are efficiently formed on the surface layer. The number of protrusions with a height of 1 nm or more and less than 10 nm as measured by AFM increases. On the other hand, the height as measured by non-contact optical roughness measurement is 10 nm. The number of the above protrusions is greatly reduced, so the windability is reduced, and the result is a film whose windability is greatly deteriorated.

(Comparative example 3)

Except that the average primary particle size of the particles added in Example 1 was set to 350 nm as described in Table 1, the rest was the same as in Example 1 to obtain a biaxially aligned film. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4.

Since particles with a large particle size are used, the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement has greatly increased, as a result, the transfer defect has been greatly deteriorated.

(Comparative Example 4)

Except that PET-1, which is the raw material of the P1 layer, and sodium stearate (crystal nucleating agent-1) belonging to the crystallization nucleating agent are blended in the amounts described in Table 1, and the atmospheric pressure glow discharge treatment is not carried out, it is introduced to the sequential biaxial stretching Except for the machine, the remaining biaxial alignment film was obtained by the same method as in Example 1. Table 4 and Table 5 show the physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film.

In Comparative Example 4, since a crystal nucleating agent was added, the number of protrusions with a height of 1 nm or more and less than 10 nm measured by AFM was significantly reduced compared to Example 1, and the coilability was greatly deteriorated.

(Comparative Example 5)

Except that the film thickness is set to 25 μm, the biaxial alignment film is obtained in the same manner as in Comparative Example 1. The physical properties, surface protrusion shape, and characteristic evaluation of the obtained biaxially aligned film are shown in Tables 3 and 4. Comparative Example 5 is a film whose windability is greatly deteriorated as in Comparative Example 1. The film of Comparative Example 5 was subjected to green sheet evaluation and photoresist evaluation according to the above methods. As a result, wrinkles or damage occurred on the film surface due to the deterioration of the rollability, and the haze of the film also increased. As a result, as shown in Table 5 and Table 6, the green sheet evaluation and the photoresist evaluation deteriorated significantly.

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

(Industrial availability)

The thermoplastic resin film of the present invention has good transparency, smoothness, and slipperiness, and can also be used for film formation. The damage resistance in the processing step is improved, so it can be suitably used as a polyester film for a dry film photoresist support used as a single-area layer photosensitive resin composition or an optical device substrate film, a release film for a ceramic capacitor, and a magnetic Film for recording media.

Claims (7)

A biaxially oriented thermoplastic resin film, the surface of at least one side meets the following (1) and (2); (1) When the number of protrusions with a height of 10 nm or more measured by non-contact optical roughness measurement is A (pieces/mm ² ), A is 2.0×10 ³ or more and 2.5×10 ⁴ or less; (2) When the number of protrusions with a height of 1 nm or more and less than 10 nm measured by an atomic force microscope (AFM: Atomic Force Microscope) is set to B (pieces/mm ² ), B is 1.8×10 ⁶ or more and 1.0×10 ⁷ or less. The biaxially oriented thermoplastic resin film according to claim 1, wherein the layer constituting the surface satisfying (1) and (2) contains particles having an average particle diameter of 10 nm or more and 300 nm or less. Such as the biaxially oriented thermoplastic resin film of claim 1 or 2, in which, The surface satisfying (1) and (2) is defined as C (pieces/mm ² ) when the number of protrusions with a height of 60 nm or more measured by non-contact optical roughness measurement is 90 or less. The biaxially oriented thermoplastic resin film according to any one of claims 1 to 3, wherein it is used as a release film. The biaxially oriented thermoplastic resin film of any one of claims 1 to 3 is used as a dry film photoresist support film. The biaxially aligned thermoplastic resin film according to any one of claims 1 to 3, which is used as a support film formed as a green sheet in the step of manufacturing a multilayer ceramic capacitor. Such as the biaxially oriented thermoplastic resin film of any one of claims 1 to 3, which is a base film for magnetic recording media used in a coating type digital recording method.

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