JP7283040B2 - thermoplastic resin film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermoplastic resin film having fine protrusions of a specific shape on its surface.

Thermoplastic resins are used in various industrial fields because of their good workability. Products obtained by processing these thermoplastic resins into films play an important role in today's life, such as industrial applications, optical product applications, and packaging applications. 2. Description of the Related Art In recent years, electronic information equipment has become more compact and highly integrated, and along with this, there is a demand for improved workability of films used in the production of electronic information equipment. In particular, in the production of electronic information equipment, it is common to laminate other materials on the surface of the film and process the entire film. It is a means. On the other hand, increasing the smoothness of the film tends to reduce the slipperiness of the film. It was difficult to improve.

In order to meet the above requirements, it is necessary to impart slipperiness, smoothness, and processability to the film surface. Techniques for improving are disclosed. Further, Patent Document 3 discloses a technique for improving slipperiness by incorporating particles into a film and performing a special treatment.

JP 2016-175356 A JP 2016-221853 A JP-A-2001-354785

However, if the particles are not contained, although the smoothness is excellent, the slipperiness is reduced, and as a result, the processability is not improved. Otherwise, there is a problem that processability is not satisfied due to aggregation of particles or shedding of particles. In view of the above circumstances, an object of the present invention is to provide a biaxially oriented thermoplastic resin film that has smoothness and lubricity and also improved workability.

In order to solve the above problems, the present invention has the following configurations. That is, [I] at least one surface (A surface) is measured by AFM (Atomic Force Microscope) _by the _following method. is less than 20 nm and the average area (A top ) of R _top (nm) or more of the protrusions having a protrusion height of R _top (nm) or more is 8 nm ² or more and 903 nm ² _or less. plastic resin film.
[AFM measurement method]
Apparatus; NanoScope 3 type SP manufactured by Digital Instruments
M Control Station SPM Unit; Atomic Force Microscope (AFM)
Cantilever: Silicon single crystal Scanning mode: Tapping mode Scanning speed: 0.8Hz
Measurement field of view: 1 μm square Sample line: 256
Flatten Auto: Order 3
Sample preparation: 23°C, 65% RH, 24 hours stationary AFM measurement environment: 23°C, 65% RH
The image of the film surface obtained under the above measurement conditions is captured by Digital Instur.
Analysis is performed using the analysis software attached to the NanoScope type 3 SPM control station manufactured by uments. A reference plane of the film surface is automatically determined from the resulting image of the film surface. From the reference plane, the threshold value of the protrusion height is set to 1 nm, 2 nm, and 1 nm.
The number of protrusions obtained at each threshold value is counted, and the threshold value that is 1 nm lower than the threshold value at which the number of protrusions to be counted becomes 0 for the first time is defined as R _top (nm).
Measurements are performed 20 times at different locations, and the average value is defined as R _top (nm).

Measurements are performed 20 times at different locations, and the average value is defined as R _top (nm).
[II] The average area A _top of the regions where the protrusions on the A surface have a protrusion height of R _top (nm) or more, and the protrusions are R _top (nm) or more, and the protrusions of 1 nm or more measured by AFM The thermoplastic resin film according to [I], wherein the ratio of the average area A _{1 nm} of the regions of the protrusions having a height of 1 nm or more (A _top /A _{1 nm} × 100) is 0.01 to 20. .
[III] The thermoplastic resin film according to [I] or [II], wherein R _top of the A side is 3 nm or more and less than 20 nm.
[IV] The thermoplastic according to any one of [I] to [III], wherein the number of projections having a projection height of 1 nm or more on the A side is 3.0×10 ⁸ /mm ² or more. resin film.
[V] The thermoplastic resin film according to any one of [I] to [IV], wherein the surface A has a surface hardness of 0.5 to 5.0 GPa.
[VI] The thermoplastic resin film according to any one of [I] to [V], wherein the layer constituting the A side does not substantially contain particles.

The biaxially oriented thermoplastic resin film of the present invention has excellent smoothness and slipperiness, as well as excellent workability.

FIG. 2 is a conceptual diagram showing R _top , A _top , and A _{1 nm} measured with an AFM (Atomic Force Microscope).

The present invention will be described in detail below.

The thermoplastic resin referred to in the present invention is a resin that exhibits plasticity when heated. Polyesters having an ester bond in the main chain, as typified by polymers from lentephthalate, polymers from 1,4 cyclohexanedimethanol, poly-P-ethyleneoxybenzoate, polyarylate, polycarbonate, etc., and copolymers thereof , Polyamides, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethylpentene, polybutene having an admin bond in the main chain, as typified by nylon 6, nylon 66, nylon 610, nylon 12, nylon 11, etc. , polyisobutylene, polystyrene, polyolefins consisting mainly of hydrocarbons, polyether sulfone (PES), polyphenylene oxide (PPO), polyether ether ketone (PEEK), polyethylene oxide, polypropylene oxide, poly Polyethers typified by oxymethylene, halogenated polymers typified by polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polychlorotrifluoroethylene, polyphenylene sulfide (PPS), polysulfone and copolymers thereof These include coalescence, modification, polyimide, and the like.

In the present invention, polyester, polyolefin, polyphenylene sulfide (PPS), and polyimide (PI) are preferably used as main components from the viewpoint of transparency and film formability, and among these, polyester is more preferable. The term "main component" as used herein refers to a component contained in an amount of more than 50% by mass and 100% by mass or less in 100% by mass of all components of the film.

The polyester referred to in the present invention is obtained by polycondensation of a dicarboxylic acid component and a diol component. In the present specification, the term "constituent" refers to a minimum unit that can be obtained by hydrolyzing a polyester.

terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, Aromatic dicarboxylic acids such as 4,4'-diphenyl ether dicarboxylic acid, or ester derivatives thereof can be mentioned.

Diol constituents constituting such polyesters include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, and 1,3-butanediol. and alicyclic diols such as cyclohexanedimethanol and spiroglycol, and diols in which a plurality of the above diols are linked. Among them, from the viewpoint of mechanical properties and transparency, polyethylene terephthalate (PET), polyethylene-2,6-naphthalene dicarboxylate (PEN), and isophthalic acid and naphthalene dicarboxylic acid are copolymerized with some of the dicarboxylic acid components of PET. However, polyester obtained by copolymerizing cyclohexanedimethanol, spiroglycol, and diethylene glycol as part of the diol component of PET is preferably used.

The thermoplastic resin film of the present invention is preferably biaxially oriented. By being biaxially oriented, the mechanical strength of the film can be improved and slipperiness can be improved. The term "biaxially oriented" as used herein refers to a pattern showing a biaxially oriented pattern in wide-angle X-ray diffraction. A biaxially oriented thermoplastic resin film can generally be obtained by stretching an unstretched thermoplastic resin sheet in the longitudinal direction and the width direction of the sheet, followed by heat treatment to complete crystal orientation. Details will be described later.

In the thermoplastic resin film of the present invention, at least one surface (A surface) has the largest slice level measured by AFM (Atomic Force Microscope) by the _method described later. The average area ( _{A top} ) of the protrusions having a top (nm) of less than 20 nm and a protrusion height of R _top (nm) or more, where the protrusions are R _top (nm) or more, is 5 _nm ² or more and 1000 nm ² or less must be. R _top (nm) in the present invention reflects the height of protrusions present on the film surface. If R _top (nm) is 20 nm or more, defects may occur on the other surface of the film when the film is wound into a roll, or protrusions may occur on other layers when laminating another layer on the surface of the film. As a result of giving defects, the workability may deteriorate. Moreover, when the R _top is small, the film does not have projections, and the slipperiness of the film may be deteriorated. R _top (nm) is preferably 3 nm or more and less than 20 nm, more preferably 5 nm or more and 15 nm or less.

A _top (nm ² ) in the present invention reflects the cross-sectional area at the height of R _top (nm) of protrusions present on the film surface. When winding ^{the film, the A top (nm 2} _{) of} ^the A surface becomes ^the contact area with the other surface. It may cause wrinkles in the processing process. A _top (nm ² ) is preferably 5 nm ² or more and 500 nm ² or less, more preferably 5 nm ² or more and 100 nm ^{2 or} less.

The method for making the protrusion height on the film surface within the above range is not particularly limited, but for example, a method of transferring a shape to the surface using a mold such as nanoimprinting, corona treatment by UV irradiation or arc discharge, and glow discharge. surface treatment such as plasma treatment with UV irradiation, corona treatment by arc discharge, and plasma treatment by atmospheric pressure glow discharge are preferable from the viewpoint of in-line film forming adaptability and the number of fine protrusions to be formed. Plasma treatment by atmospheric pressure glow discharge is more preferable. The atmospheric pressure here is in the range of 700 Torr to 780 Torr.

In the atmospheric pressure glow discharge treatment, the film to be treated is guided between the facing electrodes and the earth roll, a plasma-exciting gas is introduced into the apparatus, and a high-frequency voltage is applied between the electrodes to excite the gas into plasma. Glow discharge is performed between electrodes. As a result, the film surface is finely ashed to form projections.

A plasma-excitable gas is a gas that can be plasma-excited under the conditions described above. Examples of plasma-exciting gases include rare gases such as argon, helium, neon, krypton and xenon, nitrogen, carbon dioxide, oxygen, fluorocarbons such as tetrafluoromethane, and mixtures thereof. Moreover, one type of plasma-excitable gas may be used alone, or two or more types may be combined in an arbitrary mixing ratio. The frequency of the high frequency voltage in plasma processing is preferably in the range of 1 kHz to 100 kHz. In addition, the discharge treatment intensity (E value) obtained by the following method is preferably in the range of 10 to 2000 W min/m ² from the viewpoint of forming protrusions, more preferably 40 to 500 W min/m ² . be. If the discharge treatment strength (E value) is too low, protrusions may not be formed sufficiently, and if the discharge treatment strength (E value) is too high, the thermoplastic resin film will be damaged or ashing will progress. However, there are cases where desirable projections are not formed.
<How to obtain the discharge treatment intensity (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)
When the thermoplastic resin film of the present invention is subjected to the above surface treatment, the surface temperature of the film during the surface treatment is preferably 150° C. or lower. It is more preferably 100° C. or lower, most preferably 50° C. or lower. If the surface temperature is higher than 150° C., crystallization of the film may proceed, forming coarse protrusions on the surface, and ashing may not proceed. On the other hand, if the surface temperature of the film is too low, ashing may occur with difficulty, and preferable protrusions may be difficult to form. is preferred. Also, the surface treatment temperature can be adjusted by cooling the surface opposite to the treated surface with a cooling roll or the like.

Further, in the thermoplastic resin film of the present invention, the A surface has an average area A top of the protrusions having a protrusion height of R _top (nm) or more, and the average area A _top of the region where the protrusions are R _top (nm) or more. The ratio of the average area A _{1 nm} of the regions where the protrusions are 1 nm or more (A _top /A _{1 nm} × 100) is preferably 0.01 to 20. .

When A _top /A _{1 nm} × 100 is large and exceeds 20, the A surface has a projection diameter of R _top (nm) at a height of 1 nm and a height of 1 nm, at which no projections of 1 nm height are present. The diameter of the protrusion does not change greatly at that time, or the shape of the protrusion having a height of R _top (nm) indicates that the diameter increases as the height of the protrusion increases. In the absence of protrusions with a height of 1 nm, when the films come into contact with each other at a position closer to the film surface than R _top (nm) on the A side, the frictional force increases and the lubricity may decrease. The diameter of the protrusion with a height of R _top (nm) and the diameter of the protrusion with a height of 1 nm are not significantly different, or the shape of the protrusion with a height of R _top (nm) is different from the height of the protrusion. When the diameter increases as the R.sub.top increases, when the films come into contact with each other at _R.sub.top (nm) of the A surface, the contact area increases and the lubricity may decrease. A _top /A _{1 nm} × 100 is more preferably 10 or less. On the other hand, when A _top /A _{1 nm} × 100 is small, it means that the A surface has thin protrusions having a height of R _top (nm). If the shape of the protrusions having a height of R _top (nm) is thin, the protrusions may be scraped off by contact with other films, contaminating the processing steps using the present invention. It is more preferably 0.1 or more, and still more preferably 1 or more. FIG. 1 shows a conceptual diagram showing R _top , A _top , and A _{1 nm} measured by AFM. In FIG. 1, the reference plane is the height determined so that the distance from the reference plane on the measurement surface is 0 (positive value if higher than the reference plane, negative value if lower than the reference plane) value).

Further, in the thermoplastic resin film of the present invention, the number of protrusions having a protrusion height of 1 nm or more on the A side is preferably 3.0×10 ⁸ /mm ^{2 or} more. Due to the large number of protrusions having a protrusion height of 1 nm or more, when another layer is laminated on the A side, for example, when a release layer, an adhesive layer, or a photosensitive resin layer is provided by coating, fine surface capillaries Due to this phenomenon, other layers tend to spread over the entire A surface, the occurrence of defects can be suppressed, and workability is improved. The number of projections having a projection height of 1 nm or more on the A side is more preferably 4.0×10 ⁸ pieces/mm ² or more and 1.0×10 ¹⁰ pieces/mm ² or less.

R _top (nm), A _top /A _{1 nm} × 100 on the A side of the thermoplastic resin film of the present invention, and in order to make the number of protrusions having a protrusion height of 1 nm or more within a preferable range, atmospheric pressure glow discharge When the surface A of the present invention is formed by treatment, control of the temperature of a cast drum in the film forming method described below, control of the crystallinity of the thermoplastic resin constituting the film, and the like can be mentioned.

In general, unstretched films of thermoplastic resin films, especially PET and PEN, are treated by atmospheric pressure glow discharge treatment, and even in unstretched films, portions with high crystallinity (conformation of molecular chains in the crystal structure) When ashing the surface of a film that has a portion with crystals (hereinafter sometimes referred to as a crystalline portion) and a portion without (hereinafter sometimes referred to as an amorphous portion), the soft amorphous portion is ashed first. go. By subdividing the crystalline part and the amorphous part, finer protrusions can be formed by atmospheric pressure glow discharge treatment, and by increasing the crystalline part, the soft amorphous part can be obtained. It is possible to increase the height of the protrusion by shaving deeply. For example, with regard to the crystalline portion of the thermoplastic resin, crystallinity is enhanced by raising the temperature of the cast drum in the film forming method described later to create fine crystals, or by adding a crystallization accelerator or the like to the thermoplastic resin. , R _top (nm) tends to be large, A _top /A _{1 nm} × 100 is small, and the number of protrusions having a protrusion height of 1 nm or more tends to increase. The thermoplastic resin film of the present invention has a Q value (Quality factor) of resonance frequency at 15 GHz measured by a molecular orientation meter of 4.2×10 ³ or more and 6.0×10 ³ or less. is preferred. Generally, the larger the Q value of the resonance frequency, the more stable the vibration. In the resin, the Q value becomes higher as the resin is biaxially oriented and the orientation of the molecular chains is aligned. By setting the Q value within the above range, it becomes easy to form fine projections having a preferable shape during atmospheric pressure glow discharge treatment. In the method of setting the Q value in the above range, an unstretched film made of a thermoplastic resin having a crystalline portion and an amorphous portion is stretched at an area magnification of 10 times or more and 25 times or less, and the temperature is below the stretching temperature of the thermoplastic resin. and heat treatment.

Also, by nano-dispersing other thermoplastic resin components in the thermoplastic resin constituting the film, R _top (nm) tends to increase. It is also an effective means to increase the strength of the atmospheric pressure glow discharge treatment and the activity of the plasma-exciting gas used in the atmospheric pressure glow discharge treatment.

The surface hardness of the A side of the thermoplastic resin film of the present invention is preferably 0.5 to 5.0 GPa. If it is less than 0.5 GPa, the film may be soft and the film surfaces may easily stick to each other, resulting in poor lubricity. If it exceeds 5.0 GPa, the film surface may be hard and poor in workability. More preferably, it is 2.0 to 5.0 GPa.

The thermoplastic resin film of the present invention has an intrinsic viscosity (IV) of 0.55 or more, more preferably 0.75 or more. IV is a number that reflects the length of the molecular chain, and the longer the molecular chain, the easier it is to clearly form a crystalline part and an amorphous part in the same molecular chain. This is preferable because it facilitates formation of finer protrusions.

The surface free energy (mN/m) of the A side of the thermoplastic resin film of the present invention is preferably 40 or more and 48 or less. It is more preferably 43 or more and 45 or less. If it is more than 48 or less than 40, adhesion may be poor when another layer is laminated on the A side, which may be a drawback. In the film forming method described later, which includes the step of subjecting the film surface to atmospheric pressure glow discharge treatment and then heat treatment, the functional groups formed by ashing by the atmospheric pressure glow discharge treatment lose their activity due to the heat treatment, thereby reducing the surface free energy. can be a range.

The thermoplastic resin film of the present invention preferably has a coefficient of friction between the A surface and the metal under the measurement conditions described below of 0.20 μk or more and 0.55 μk or less. It is more preferably 0.20 μk or more and 0.35 μk or less. If it exceeds 0.55 μk, the film of the present invention cannot be processed due to insufficient lubricity. If it is less than 0.20 μk, winding misalignment may occur when winding the film of the present invention.

The thermoplastic resin film of the present invention may contain organic particles, inorganic particles, or both as long as the properties of the present invention are not impaired. It is preferred that the layer constituting the A side of is substantially free of particles. "Substantially free of particles" means that the content of particles relative to the thermoplastic resin is 1000 ppm or less. It is more preferably 500 ppm or less, still more preferably 50 ppm or less, and most preferably 10 ppm or less.

The thermoplastic resin film of the present invention may be a single layer film or a laminated film of two or more layers. In the case of a laminated film of two or more layers, for the purpose of preventing scratches during film formation and improving abrasion resistance during stretching, layers other than the layer constituting the A side are added without impairing the characteristics of the present invention. Particles may be contained within a range.

The thermoplastic resin film of the present invention preferably has a thickness of 10 μm or more and 500 μm or less, more preferably 10 μm or more and 40 μm or less. Particularly preferably, it is 15 μm or more and 20 μm or less. If it exceeds 40 μm, optical properties such as light transmittance of the film may be deteriorated. If the thickness is less than 10 μm, the flatness may deteriorate when heat is applied in the process of using the film for various purposes.

Next, the method for producing a 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 only to the products obtained by such examples. .

As a method for obtaining the polyester used in the present invention, a conventional polymerization method can be employed. For example, a dicarboxylic acid component such as terephthalic acid or an ester-forming derivative thereof and a diol component such as ethylene glycol or an ester-forming derivative thereof are transesterified or esterified by a known method, and then subjected to a melt polymerization reaction. You can get it by doing. Moreover, if necessary, the polyester obtained by the melt polymerization reaction may be subjected to a solid phase polymerization reaction at a temperature not higher than the melting point temperature of the polyester.

The polyester film of the present invention can be obtained by a conventionally known production method, and the A side can be made to have the preferred physical properties as described above by carrying out the stretching and heat treatment steps under the following conditions.

For the polyester film of the present invention, a method (melt casting method) of heating and melting a dried raw material in an extruder and extruding it from a nozzle onto a cooled cast drum to process it into a sheet can be used. As another method, the raw material is dissolved in a solvent, the solution is extruded from a die onto a support such as a cast drum or an endless belt to form a film, and then the solvent is removed from the film layer by drying to form a sheet. A method (solution casting method) or the like can also be used.

When producing a laminated polyester film of two or more layers by a melt casting method, an extruder is used for each layer constituting the laminated polyester film, the raw materials of each layer are melted, and these are combined into a confluence provided between the extrusion device and the nozzle. It is preferable to use a method in which the melted layers are laminated in an apparatus, then guided to a spinneret, extruded from the spinneret onto a cast drum, and processed into a sheet. The laminated sheet is adhered and solidified by static electricity on a drum cooled to a surface temperature of 20° C. or higher and 60° C. or lower to produce an unstretched sheet. The temperature of the casting drum is more preferably 25° C. or higher and 60° C. or lower, and still more preferably 40° C. or higher and 55° C. or lower. If the temperature is 20° C. or lower, formation of projections on the surface of the film may not be sufficient after the film is irradiated with plasma and biaxially stretched. If it exceeds 60°C, the film may stick to the cast drum, making it difficult to obtain an unstretched sheet.

Next, the unstretched film obtained here is subjected to a surface treatment such as a method of transferring a shape to the surface using a mold like nanoimprint, a corona treatment by ultraviolet light irradiation or arc discharge, or a plasma treatment by glow discharge. These surface treatments may be performed immediately after obtaining an unstretched film, after slightly stretching the film, or after stretching in the longitudinal and/or transverse directions. In the present invention, the unstretched film is preferably surface-treated. The surface to be surface-treated may be either the surface in contact with the cast drum (drum surface) or the surface not in contact with the cast drum (non-drum surface). At that time, the surface temperature of the film surface to be surface-treated is controlled so that it does not become too high.

Thereafter, the stretched film is biaxially stretched and biaxially oriented as necessary. As a stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. A sequential biaxial stretching method in which stretching is first carried out in the longitudinal direction and then in the width direction is effective in obtaining the film of the present invention without stretching breakage.

In the biaxial stretching, the area ratio (stretch ratio in the longitudinal direction×stretch ratio in the width direction) is preferably 10 times or more and 25 times or less, more preferably 15 times or more and 20 times or less. By biaxially orienting the film through the stretching step, the shape imparted to the unstretched film is subdivided, and a more preferable protrusion shape, particularly the number of protrusions having a protrusion height of 1 nm or more, can be set within a preferable range. If the area magnification is less than 10 times, the number of protrusions having a protrusion height of 1 nm or more may decrease, or Atop (nm) may increase. If the area magnification exceeds 25 times, the film is likely to break due to stretching.

Heat treatment is also a preferred embodiment after biaxially oriented by biaxial stretching. The heat treatment temperature is preferably from the melting point of the thermoplastic resin used -40° C. or higher to the melting point or lower. When the thermoplastic resin to be used is a crystalline polyester such as PET or PEN, and the shape is imparted to the unstretched film by the ashing effect of the atmospheric pressure glow discharge treatment, the crystalline portion remaining after the ashing treatment is It is subdivided by stretching, and further by heat treatment, crystals grow with the portions as nuclei, and the protrusions can be formed into a desired shape. If the heat treatment temperature is less than the melting point -40°C, crystal growth may not be sufficient, and if it exceeds the melting point, the projections may melt.

[Method for evaluating properties]
A. Evaluation by AFM (Atomic Force Microscope) (i) R _top (nm)
An image of the film surface obtained by the following measurement method is analyzed using the attached analysis software. A reference plane of the film surface is automatically determined from the resulting image of the film surface. From the reference plane, the threshold value of the protrusion height is determined for each 1 nm, 2 nm, etc., and the number of protrusions obtained at each threshold value is counted. Let R _top (nm).
(ii) A _top (nm ² )
Let A _top (nm ² ) be the average area of the protrusions at the threshold value R _top (nm) calculated by the attached analysis software.
(iii) A _top /A _{1 nm} × 100
The average area of protrusions at a threshold value of 1 nm calculated by the attached analysis software is defined as A _{1 nm} (nm ² ), and calculated as A _top /A _{1 nm} ×100.
(iv) Number of projections having a projection height of 1 nm or more (pieces/mm ² )
The attached analysis software counts the number of projections obtained at a threshold of 1 nm, converts it into a value per square millimeter, and determines the number of projections having a height of 1 nm or more.
[AFM measurement method]
Apparatus; NanoScope 3 type SPM control station SPM unit manufactured by Digital Instruments; atomic force microscope (AFM)
Cantilever: Silicon single crystal Scanning mode: Tapping mode Scanning speed: 0.8Hz
Measurement field of view: 1 μm square Sample line: 256
Flatten Auto: Order 3
Sample preparation: 23°C, 65% RH, 24 hours stationary AFM measurement environment: 23°C, 65% RH
Change the location and measure 20 times, and find the average value.

B. Metal friction coefficient (μk)
A tape running tester SFT-700 type (manufactured by Yokohama System Laboratory Co., Ltd.) is used to slit the film into a tape shape with a width of 12.65 mm, and a load of 100 g is applied to the film in an atmosphere of 23 ° C. and 65% RH. The friction coefficient (μk) after running was obtained from the following formula. The surface of the film to be measured was set so as to be in contact with the guide, and the average value of five measurements was obtained.

μk=2/πln( _T2 / _T1 )
T ₁ : tension load (100 gf)
T ₂ : Tension guide diameter during running: 6mmΦ
Guide material: SUS27 (surface roughness 0.2S)
Winding angle: 90°
Mileage: 10cm
Running speed: 3.3 cm/sec C.I. Thickness (μm)
The thickness of the film was measured using a dial gauge in accordance with JIS K7130 (1992) A-2 method, with 10 sheets of the film stacked at five arbitrary points. The average value was divided by 10 to obtain the film thickness.

When the film was a laminated film, the thickness of each layer was determined by the following method. A cross section of the film is cut out with a microtome in a direction parallel to the width direction of the film. The cross section is observed with a scanning electron microscope at a magnification of 5000 times to determine the thickness ratio of each laminated layer. The thickness of each layer is calculated from the obtained lamination ratio and the film thickness described above.

D. Film intrinsic viscosity IV (dl/g)
The film of the present invention is dissolved in 100 ml of orthochlorophenol (solution concentration C=1.2 g/dl), and the viscosity of the solution at 25° C. is measured using an Ostwald viscometer. Also, the viscosity of the solvent is measured in the same manner. Using the obtained solution viscosity and solvent viscosity, [η] (dl/g) is calculated according to 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 Huggins constant (assumed to be 0.343)).

E. Surface free energy of A surface (mN/m)
After leaving the sample in an atmosphere of room temperature 23° C. and humidity 65% for 24 hours, using a contact angle meter CA-D type (manufactured by Kyowa Interface Science Co., Ltd.) in that atmosphere, water, ethylene based on JIS K6768 It is calculated as the sum of dispersion force, polar force, and hydrogen bonding force from the contact angles of glycol, formamide, and methylene iodide with respect to the film.

F. Surface hardness of A side (GPa)
Surface hardness is determined by a nanoindentation method (continuous rigidity measurement method) using an ultra-micro hardness tester NanoIndenter DCM manufactured by MTS Systems. The indenter used is a diamond triangular pyramid indenter, the measurement atmosphere is room temperature in the atmosphere, the indentation depth is 10 nm, and 30 μm square is measured at 16 points at 10 μm intervals, and the elastic modulus of each point is averaged. Harden.

G. Resist Layer Coatability On the A side of the film of the present invention, a photosensitive resin layer is coated in a dark room by a gravure coating method so as to have a coating thickness of 5 μm. The photosensitive resin layer comprises a copolymer consisting of methacrylic acid, methyl methacrylate, ethyl acrylate, and butyl methacrylate as thermoplastic resins, and trimethylolpropane triacrylate and polyethylene glycol (number average molecular weight: 600) dimethacrylate as photosensitive materials. , benzophenone and dimethylaminobenzophenone as photoinitiators, hydroquinone as stabilizer, and methyl violet as colorant. After coating, the film is observed in an area of 300 mm×500 mm for missing coating or coating defects due to surface transfer, and evaluated as follows. A is the best and D is the worst.

A: The number of coating defects is 9/m ² or less B: The number of coating defects is 10 to 19/m ²
C: The number of coating defects is 20 to 29 / m ²
D: The number of coating defects is 30/m ² or more.

H. Resist Evaluation G. The laminate consisting of the film of the present invention and the photosensitive resin layer obtained in Section 1 is stacked so that the photosensitive resin layer is in contact with a 6-inch Si wafer with one side mirror-polished, and laminated using a rubber roller, A reticle patterned with chromium metal is placed thereon, and the reticle is exposed using an I-ray (ultraviolet rays having a peak at a wavelength of 365 nm) stepper. Subsequently, after peeling off the polyester film from the resist layer, the Si wafer with the resist layer is placed in a container containing a developing solution and developed for about 1 minute. After that, it is taken out from the developer and washed with water for about 1 minute. 30 lines of L/S (μm) (Line and Space)=10/10 μm of the resist pattern created after development were observed with a scanning electron microscope SEM at a magnification of about 800 to 3000, and defects in the pattern were determined. A certain number is evaluated as follows.

A; 4 or less cracks B; 5 to 9 cracks C; 10 to 15 cracks D; 16 cracks or more A is the best, D is the worst.

I. Ceramic green sheet manufacturing property On the A side of the film of the present invention, a coating solution in which a cross-linked primer layer (trade name BY24-846 manufactured by Dow Corning Toray Silicone Co., Ltd.) was adjusted to a solid content of 1% by weight was applied and dried. , It is applied with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dried and cured at 100° C. for 20 seconds. Within one hour thereafter, 100 parts by weight of an addition reaction type silicone resin (trade name LTC750A manufactured by Toray Dow Corning Silicone Co., Ltd.) and 2 parts by weight of a platinum catalyst (trade name SRX212 manufactured by Toray Dow Corning Silicone Co., Ltd.) were added. A coating solution adjusted to a solid content of 5% by weight is applied by gravure coating so that the coating thickness after drying is 0.1 μm, dried and cured at 120° C. for 30 seconds, and wound up to obtain a release film.
As ceramic slurry, 100 parts by weight of barium titanate (trade name HPBT-1 manufactured by Fuji Titan Industry Co., Ltd.), 10 parts by weight of polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.), and 5 parts by weight of dibutyl phthalate and 60 parts by weight of toluene-ethanol (weight ratio: 30:30), glass beads with a number average particle diameter of 2 mm are added, mixed and dispersed in a jet mill for 20 hours, and then filtered to prepare a paste. The resulting ceramic slurry is coated on a release film with a die coater so that the thickness after drying becomes 2 μm, dried, and wound to obtain a green sheet. The green sheet wound as described above is unwound and visually observed without being peeled off from the release film to check the presence or absence of pinholes and the state of coating on the surface and edges of the sheet. The area to be observed has a width of 300 mm and a length of 500 mm. While illuminating the green sheet molded on the release film from the back with a backlight unit of 1000 lux, observe the state of pinholes due to missing coating or dents due to surface transfer on the back of the release film, as follows. evaluate. A is the best in manufacturability, and C is the worst.
A: Neither pinhole nor dent.
B: No pinholes, 3 or less dents observed C: Pinholes or 4 or more dents, or both.

J. Q value of film The film of the present invention is cut into a square of 15 cm square, and the Q value is evaluated at a frequency of 15 GHz using MOA-6015 manufactured by Oji Scientific Instruments. The film is rotated by 30°, six points are measured up to 150°, and the average of the Q values of the six points is taken as the Q value of the film.

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not necessarily limited to these.

[Production of PET-1] Terephthalic acid and ethylene glycol were polymerized in a conventional manner using antimony trioxide as a catalyst to obtain melt-polymerized PET containing substantially no particles. The obtained melt-polymerized PET had a glass transition temperature of 81° C., a melting point of 255° C., and an intrinsic viscosity of 0.62.

[Production of PET-2] Using PET-1, solid phase polymerization was carried out by a conventional method to obtain solid phase polymerized PET. The obtained solid phase polymerized PET had a glass transition temperature of 81° C., a melting point of 255° C., and an intrinsic viscosity of 0.81.

[Production of PET-3] During the polymerization of PET-1, 60 nm colloidal silica dispersed in ethylene glycol was added so that the amount added to PET was 1.0% to obtain PET-3. The obtained melt-polymerized PET had a glass transition temperature of 81° C., a melting point of 255° C., and an intrinsic viscosity of 0.62.

[Production of MB-A] 95% by weight of PET-2 and 5% by weight of sodium montanate powder manufactured by Clariant were charged into an extruder with a vent hole, and the pressure in the vent hole was reduced to 1 kPa or less. While kneading, MB-A was obtained.

[Production of MB-B] 50% by weight of PET-2 and 50% by weight of polyetherimide "Ultem 1010" manufactured by SABIC were put into an extruder with a vent hole, and the pressure in the vent hole was reduced to 1 kPa or less. While kneading, MB-B was obtained.

[Production of MB-C] A water slurry (particle concentration: 20%) in which crosslinked polystyrene particles with a particle size of 400 nm are dispersed in water and PET-1 are used, and an extruder with a vent hole is used so that the particle concentration is 1%. and kneaded while reducing the pressure in the vent hole to 1 kPa or less to obtain MB-C.

[Production of MB-D] A water slurry (particle concentration: 20%) in which crosslinked polystyrene particles with a particle size of 150 nm are dispersed in water and PET-1 are used, and an extruder with a vent hole is used so that the particle concentration becomes 1%. and kneaded while reducing the pressure in the vent hole to 1 kPa or less to obtain MB-D.

[Production of PEN] Dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol were transesterified using manganese acetate as a catalyst. After completion of the transesterification reaction, PEN-A was obtained by a conventional method using antimony trioxide as a catalyst. The obtained PEN had a glass transition temperature of 124° C., a melting point of 265° C., and an intrinsic viscosity of 0.66.

(Example 1)
After PET-1 was dried under reduced pressure at 160°C for 2 hours, it was supplied to an extruder, melt-extruded, filtered through a filter, and then held at 25°C using an electrostatic casting method on a cooling roll through a die. It was wrapped around a casting drum and solidified by cooling to obtain an unstretched film. This unstretched film was led between the opposing electrodes and earth rolls, nitrogen gas was introduced into the apparatus, and atmospheric pressure glow discharge treatment was performed under conditions where the E value was 160 W·min/m ² . At that time, the earth roll was cooled so that the film surface temperature of the treated surface became 30°C.
The unstretched film after the treatment was successively stretched 3.3 times in the longitudinal direction and 3.3 times in the width direction, for a total of 10.9 times, by a biaxial stretching machine, and then heat-treated at 235° C. under a constant length. After that, a relaxation treatment was applied in the width direction to obtain a biaxially oriented film having a thickness of 20 μm. The properties, etc. of the obtained biaxially oriented film are shown in the table. The film had no problem in both processability and slipperiness.

(Example 2-12)
A biaxially oriented film with a thickness of 20 μm was obtained in the same manner as in Example 1, except that the resin constituting the layer A, the cast drum temperature, the E value, and the plasma treatment atmosphere were changed as shown in the table. The properties, etc. of the obtained biaxially oriented film are shown in the table.

In Example 2, the IV of the film was high, the surface characteristics of the A side could be made good, and the film had good workability and slipperiness.

In Example 3, the temperature of the cast drum was high, the surface characteristics of the A side could be improved, and the film was excellent in workability and slipperiness.

In Example 4, the processing atmosphere was a mixed gas of nitrogen and oxygen to increase the activity of the plasma excitation gas. It is a film with good processability and slipperiness, the number of protrusions having a protrusion height of 1 nm or more increases, especially the resist layer coatability and resist properties are good, and the processability is improved. It was a great film.

In Examples 5, 6, and 9, 0.5% sodium montanate was added as a crystallization accelerator to the resin constituting the A layer, so that the surface characteristics of the A side could be made particularly good, and workability was improved. The film had good slipperiness, increased the number of protrusions having a height of 1 nm or more, and had particularly good resist layer coatability and resist properties, and improved workability.

In Example 8, since the E value of the plasma treatment was small, the film was slightly inferior in slipperiness and workability, but it was at a level that poses no problem for practical use.

In Examples 10, 11, and 12, 10% by weight of polyetherimide was added to the resin constituting the A layer as a thermoplastic resin for nano-dispersion. It was a film with good properties and slipperiness.

(Example 13)
PET-1 is used as the resin constituting layer A, and a raw material obtained by blending 97% by weight of PET-1 and 3% by weight of PET-3 is used as the resin constituting layer B. After drying at 160 ° C. for 2 hours, The resins forming the A layer and the resin forming the B layer were put into separate extruders, laminated in a confluence device, and laminated on a casting drum maintained at 40° C. to obtain a laminated sheet. The layer A side of the laminated sheet was subjected to plasma treatment under the conditions shown in the table to obtain a film having a thickness of 16 μm in the same manner as in Example 4. The thickness of the A layer was 15.5 μm, and the thickness of the B layer was 0.5 μm. The properties of the resulting film are shown in the table. As in Examples, the surface properties of the A side were particularly good, and the film had good workability and slipperiness.

(Example 14)
After obtaining an unstretched film in the same manner as in Example 3, instead of the atmospheric pressure glow discharge treatment, the unstretched film was subjected to arc discharge corona in an air atmosphere under conditions where the E value was 160 W min / m ² . A biaxially oriented film was obtained in the same manner as in Example 3, except that the treatment was performed. The properties, etc. of the obtained film are shown in the table. The film was excellent in workability and slipperiness.

(Comparative example 1)
After obtaining an unstretched film in the same manner as in Example 1, a biaxially oriented film was obtained in the same manner as in Example 1 except that it was sequentially introduced into the biaxial stretching machine without performing atmospheric pressure glow discharge treatment. Obtained. The properties, etc. of the obtained biaxially oriented film are shown in the table. Since the atmospheric pressure glow discharge treatment was not performed, the surface characteristics of the A side were inferior, and the film was particularly large in μk and inferior in slipperiness. In addition, evaluation of the resist layer coatability and evaluation of the ceramic green sheet manufacturability could not be performed because the film could not be processed due to poor lubricity.

(Comparative example 2)
A film was obtained in the same manner as in Comparative Example 1, except that the resin constituting the A layer was as shown in the table. The properties of the resulting film are shown in the table. Since the atmospheric pressure glow discharge treatment was not performed, the surface characteristics of the A side were inferior, and the film was particularly large in μk and inferior in slipperiness. In addition, evaluation of the resist layer coatability and evaluation of the ceramic green sheet manufacturability could not be performed because the film could not be processed due to poor lubricity.

(Comparative Example 3)
A film was obtained in the same manner as in Example 1 except that ultraviolet rays were irradiated at the intensity shown in the table instead of the atmospheric pressure glow discharge. Since the treatment strength was small, the surface characteristics of the A side were inferior, and the film was particularly large in μk and inferior in slipperiness. In addition, evaluation of the resist layer coatability and evaluation of the ceramic green sheet manufacturability could not be performed because the film could not be processed due to poor lubricity.

(Comparative Example 4)
A film was obtained in the same manner as in Example 1 by performing glow discharge treatment under reduced pressure at the intensity shown in the table instead of atmospheric pressure glow discharge. Since the treatment strength was high, ashing progressed on the film surface, and as a result, the surface properties of the A side were inferior, and the film was particularly large in μk and inferior in slipperiness. In addition, evaluation of the resist layer coatability and evaluation of the ceramic green sheet manufacturability could not be performed because the film could not be processed due to poor lubricity.

(Comparative Example 5)
A film was obtained in the same manner as in Comparative Example 1, except that the resin constituting the A layer was as shown in the table. The properties of the resulting film are shown in the table. Since the particles were added, the surface characteristics of the A side were inferior, and the film was inferior in resist layer coatability, resist evaluation, and ceramic green sheet producibility.

(Comparative Example 6)
A film was obtained in the same manner as in Example 1, except that the E value of the atmospheric pressure glow discharge was changed as shown in the table. Since the treatment strength was high, ashing progressed on the film surface, and as a result, the surface properties of the A side were inferior, and the film was particularly large in μk and inferior in slipperiness. In addition, evaluation of the resist layer coatability and evaluation of the ceramic green sheet manufacturability could not be performed because the film could not be processed due to poor lubricity.

(Comparative Example 7)
A film was obtained in the same manner as in Example 1, except that the film temperature during atmospheric pressure glow discharge was as shown in the table. Since the film surface temperature was high, ashing on the film surface did not proceed, and the surface properties of the A side were inferior, and the film was particularly large in μk and inferior in slipperiness. In addition, evaluation of the resist layer coatability and evaluation of the ceramic green sheet manufacturability could not be performed because the film could not be processed due to poor lubricity.

(Example 15)
A film was obtained in the same manner as in Example 1, except that the stretching and heat treatment conditions were as shown in the table. The film thickness was 16 μm. By setting the draw ratio to a more preferable range, the number of projections having a projection height of 1 nm or more was able to be set to a preferable range, and the film was excellent in workability, particularly resist layer coatability, and resist evaluation.

(Example 16)
A film was obtained in the same manner as in Example 2, except that the stretching and heat treatment conditions were as shown in the table. The film thickness was 16 μm. By setting the draw ratio to a more preferable range, the number of projections having a projection height of 1 nm or more was able to be set to a preferable range, and the film was excellent in workability, particularly resist layer coatability, and resist evaluation.

(Example 17)
A film was obtained in the same manner as in Example 8, except that the stretching and heat treatment conditions were as shown in the table. The film thickness was 16 μm. By setting the draw ratio within a more preferable range, the number of protrusions having a height of 1 nm or more was able to be within a preferable range, and the resist evaluation was good for the film.

(Example 18)
After drying PET-1 under reduced pressure at 160 ° C. for 2 hours, it was supplied to extruder A and blended at a ratio of 97% by weight of PET-1, 1% by weight of MB-C, and 2% by weight of MB-D, and dried at 160 ° C. The raw material dried under reduced pressure for 2 hours is supplied to extruder B, melted and extruded, filtered with a filter, and then passed through a die from each extruder on a cooling roll so that it becomes two layers. Then, the film was wound around a casting drum maintained at 25° C. and solidified by cooling to obtain an unstretched film. This unstretched film is guided between the facing electrodes and the earth roll so as to be processed into the raw material layer (A layer) on the extruder A side, nitrogen gas is introduced into the device, and the E value is 160 W min / m Atmospheric pressure glow discharge treatment was performed under the condition of ² . At that time, the earth roll was cooled so that the film surface temperature of the treated surface became 30°C.
The unstretched film after treatment was successively stretched 3.6 times in the longitudinal direction and 4.5 times in the width direction by a biaxial stretching machine, for a total of 16.2 times, and then heat-treated at 235° C. under a constant length. After that, a relaxation treatment was applied in the width direction to obtain a biaxially oriented film with a thickness of 16 μm. The thickness of the A layer side was 15 µm, and the thickness of the layer (B layer) on the extruder B side was 1 µm. The properties of the layer A side surface of the obtained biaxially oriented film are shown in the table. The film had no problem in both processability and slipperiness.

(Example 19)
PPS resin (polyphenylene sulfide resin "Torelina" A900 (manufactured by Toray Industries, Inc.)) was used instead of PET-1, and a biaxially oriented film with a thickness of 18 μm was prepared in the same manner as in Example 1 under the conditions shown in the table. got The properties, etc. of the obtained biaxially oriented film are shown in the table. The film had no problem in both processability and slipperiness.

(Example 20)
A biaxially oriented film having a thickness of 20 μm was obtained in the same manner as in Example 1 using PEN instead of PET-1 under the conditions shown in the table. The properties, etc. of the obtained biaxially oriented film are shown in the table. The film had no problem in both processability and slipperiness.

The thermoplastic resin film of the present invention has good smoothness and slipperiness, and can also improve processability. It can be suitably used as a film, a film for optical device substrates, a film for ceramic capacitors, and a film for magnetic recording media.

Claims (6)

R _top (nm) is less than 20 nm, where R _top (nm) is the largest value of the slice level measured by AFM (Atomic Force Microscope) on at least one side surface (A side) by the following method. and an average area (A _top ) of R _top (nm) or more of the protrusions having a protrusion height of R _top (nm) or more is 8 nm ² or more and 903 nm ^{2 or} less.
[AFM measurement method]
Apparatus; NanoScope 3 type SP manufactured by Digital Instruments
M Control Station SPM Unit; Atomic Force Microscope (AFM)
Cantilever: Silicon single crystal Scanning mode: Tapping mode Scanning speed: 0.8Hz
Measurement field of view: 1 μm square Sample line: 256
Flatten Auto: Order 3
Sample preparation: 23°C, 65% RH, 24 hours stationary AFM measurement environment: 23°C, 65% RH
The image of the film surface obtained under the above measurement conditions is captured by Digital Instur.
Analysis is performed using the analysis software attached to the NanoScope type 3 SPM control station manufactured by uments. A reference plane of the film surface is automatically determined from the resulting image of the film surface. From the reference plane, the threshold value of the protrusion height is set to 1 nm, 2 nm, and 1 nm.
The number of protrusions obtained at each threshold value is counted, and the threshold value that is 1 nm lower than the threshold value at which the number of protrusions to be counted becomes 0 for the first time is defined as R _top (nm).
Measurements are performed 20 times at different locations, and the average value is defined as R _top (nm).
The A surface is the average area A _top of the region where the protrusions have a protrusion height of R _top (nm) or more, and the protrusion height is 1 nm or more measured by _AFM . 2. The thermoplastic resin film according to claim 1, wherein the ratio (A _top /A _{1 nm} × 100) of the average area A _{1 nm} of the regions having projections of 1 nm or more is from 0.01 to 20. 3. The thermoplastic resin film according to claim 1, wherein the R _top of the A side is 3 nm or more and less than 20 nm. The thermoplastic resin film according to any one of claims 1 to 3, wherein the number of protrusions having a protrusion height of 1 nm or more on the A side is 3.0 x ¹⁰⁸ /mm2 ^{or more} . The thermoplastic resin film according to any one of claims 1 to 4, wherein the surface A has a surface hardness of 0.5 to 5.0 GPa. 6. The thermoplastic resin film according to any one of claims 1 to 5, wherein the layer constituting the A side contains substantially no particles.

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