JP2000006353A - Mold release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a uniform surface, minimize a heat deformation during thermal treatment, and prevent burrs or the like from being generated at the time of cutting, in molding various kinds of resin sheet, resin coating film, ceramic sheet or the like. SOLUTION: This mold release film is based on a biaxially orientated polyethylene-2,6-naphthalene dicarboxylate film with 50 nm or more-100 nm or below surface roughness (Ra). In this case, foreign particles with 25 μm or more max. dia. are not present and foreign particles with 5 μm or more and 25 μm or below max. dia. total 10 or less in a base film per area having 210 mm one side length and 148 mm orthogonal side length with the former (the area of 310.8 cm2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film, and more particularly to a carrier film for producing a resin sheet or a resin film formed from a resin solution, having excellent flatness, heat deformability and cutting properties, and ceramics. The present invention relates to a release film useful as a carrier film for molding such as a ceramic sheet molded from a rally, or a protective film for an adhesive layer such as an adhesive tape.

[0002]

2. Description of the Related Art A release film is used as a carrier film when forming a resin sheet, a resin film, a ceramic sheet or the like.

[0003] A resin sheet is formed by coating (casting) a resin solution made of, for example, vinyl chloride on a carrier film, removing the solvent by heating, and separating and separating the carrier film. Used for applications.

[0004] A resin film is produced, for example, by applying a coating solution obtained by dissolving a resin serving as an adhesive in a solvent to the surface of a carrier film and then heating to remove the solvent.

A ceramic sheet is formed by, for example, applying a slurry in which a ceramic powder and a binder agent or the like are dispersed in a solvent to the surface of a carrier film, removing the solvent by heating, and peeling off the carrier film. .

[0006] Recently, such resin sheets, resin coatings, ceramic sheets, and the like are often manufactured using a release film. In particular, in applications requiring high performance such as electronic parts and optical parts, such sheets and the like are used. More uniform thickness and surface properties are required for coatings than ever before.

[0007] Ceramic sheets are often laminated when manufacturing ceramic electronic components such as capacitors. In order to increase the capacitance of a capacitor, the thickness of the ceramic sheet is reduced, and furthermore, they are laminated in multiple layers. Things are increasing.

Therefore, such a resin sheet or ceramic sheet is required to have a uniform thickness, high accuracy, and a smoother surface. In order to produce uniform and smooth sheets, etc., not only high-precision equipment is required for applying a coating solution such as a resin solution, an adhesive or a ceramic slurry, but also a carrier for forming a sheet. Films are also required to have high accuracy such as flatness, dimensional stability, and flat surface.

Various types of films, for example, olefin-based films such as OPP and polyethylene terephthalate (hereinafter referred to as P)
A film or the like is used.

However, in most cases, the surface of the PET film is roughened by adding a filler or the like for the purpose of improving the winding property. Therefore, PE with filler added
When a T film, particularly a film having a rough surface, is used as a carrier film, a molded resin sheet or a ceramic sheet may have pinholes when a resin solution or the like is applied, and may have a uniform thin layer. There is a problem in that a sheet cannot be obtained and a product is defective.
Further, when laminating the formed sheets, there may be a problem that a void easily enters a lamination interface.

However, if the average particle size of the filler or the like is too small or too small, the surface roughness of the base film becomes small, the contact area between the films on the take-up roll becomes large, and abnormal peeling due to blocking occurs. May occur, and the sliding of the film may be poor, which may cause a problem in transportability during use in the process.

On the other hand, after the release film is coated with a resin solution or a ceramic slurry, it is subjected to a heat treatment for removing the solvent. The heating temperature is set to the glass transition temperature (Tg) of the base film used for the release film. In many cases, it is near or more than this, and therefore thermal deformation such as dimensional change and wrinkles occurs in the release film, and there is a problem that thickness unevenness and flatness of molded resin sheets are deteriorated and quality is deteriorated. .
In particular, when the heating temperature is increased in order to shorten the heat treatment time in order to improve the productivity of the resin sheets, there is a concern that the above-mentioned problem becomes more apparent.

The obtained resin film, sheet, ceramic sheet, etc. may be wound into a roll and then used in the next step. Often processed. For example, a resin film, sheet, or ceramic sheet may be cut into a desired size in order to remove an uncoated portion or an unnecessary portion when used in the next step while being formed into a carrier film. At this time, if the carrier film does not have sufficient rigidity, the film may not be cut immediately at the time of cutting, which may cause a problem that burrs or floating between the resin and the sheet may occur.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art and to obtain a uniform surface in molding various resin sheets, resin coatings, ceramic sheets, etc. An object of the present invention is to provide a release film which has a very small thermal deformation and no burrs or the like even when cut.

[0015]

According to the present invention, there is provided a method for manufacturing a semiconductor device having a surface roughness (R).
a) a release film having a base film of a biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film having a length of 50 nm or more and less than 100 nm, wherein a length of one side is 210 mm and a length of a side perpendicular thereto is 148 mm; There is no foreign matter having a maximum diameter of 25 μm or more in the base film per area (310.8 cm ² ), and the maximum diameter is 5 μm.
A release film characterized in that there are 10 or less foreign substances having a size of not less than 25 μm and not more than 25 μm.

[0016] The following three are preferred embodiments of the release film.

1. 150 gf / mm ^{2 at} 120 ° C.
The absolute value of the dimensional change under stress is 0.3% or less in both the film roll winding direction and the vertical direction, and the absolute value of the heat shrinkage after treatment at 200 ° C. for 10 minutes in a state where no stress is applied. A release film having a value of 1.0% or less in both the film roll winding direction and the vertical direction.

2. Release film isotropic index is 0.6 ~
1.5 and an elastic modulus of 1.0 × 10 ^{11 to} 1.7 × 1 in both the winding direction of the base film roll and the vertical direction thereof.
Release film having 0 ¹¹ dyne / cm ² .

3. On at least one side of the base film,
A release film formed by laminating at least one selected from silicone resins, fluororesins, and aliphatic waxes.

The surface roughness Ra is a surface roughness curve (Y = f (x) obtained by using a stylus type surface roughness meter, where Y: surface displacement, X: scan distance, surface Average length of displacement: Y = 0), measured length (L) in the direction of the center line
Is the value given by the following equation.

[0021]

(Equation 1)

The absolute value of the dimensional change rate is 30 m in length.
m, a strip-shaped release film cut into a width of 4 mm is mounted on a TMA (thermal stress strain measurement device) so that the distance between the chucks is 10 mm, and a stress of 150 gf / mm ² is measured in a direction in which a dimensional change rate is measured. And the temperature was raised from room temperature at a rate of 5 ° C./min, and the dimensional change when the temperature reached 120 ° C. was measured in the winding direction of the film roll and in the vertical direction thereof, and the value was obtained by the following formula. . Absolute value of dimensional change rate = | Dimension change / Distance between chucks | ×
100

A biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film is used as the base film in the present invention. The polyethylene-2,6-naphthalenedicarboxylate (hereinafter sometimes abbreviated as PEN) constituting the film is ethylene-2,6
-A polyester containing naphthalene dicarboxylate as a main repeating unit.

The PEN polymer may be a copolymer obtained by copolymerizing a small amount of a copolymer component (for example, 10 mol% or less, particularly 5 mol% or less) as long as the heat deformation resistance of the release film is not impaired.

Examples of such a copolymer component include terephthalic acid, isophthalic acid, phthalic acid, and naphthalene-2,7.
-Dicarboxylic acid, 4,4'-diphenyldicarboxylic acid,
Aromatic dicarboxylic acids such as 4,4'-diphenyl ether dicarboxylic acid, aliphatic dicarboxylic acids such as oxalic acid and adipic acid, oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid, or lower alkyl esters thereof Or diethylene glycol, 1,3
Glycols such as -propylene glycol, 1,4-tetramethylene glycol, 1,6-hexamethylene glycol, and neopentyl glycol.

Further, the PEN polymer is obtained by copolymerizing a compound having three or more functions such as glycerin, pentaerythritol, trimellitic acid, pyromellitic acid, etc. within a range where a substantially linear polymer can be obtained. Is also good.

Furthermore, in order to improve the hydrolysis resistance of the PEN polymer, part or all of the terminal hydroxyl groups and / or carboxyl groups are blocked with a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. It may be something.

The PEN polymer used in the present invention has a temperature of 35 ° C.
Intrinsic viscosity measured in an orthochlorophenol solution is 0.40 or more, more preferably 0.50 or more, especially 0.1.
A homopolymer containing only ethylene-2,6-naphthalenedicarboxylate having a repeating unit of 50 to 0.70 is excellent in mechanical properties derived from elastic modulus and thermal properties such as heat deformation resistance. This is preferred because a base film can be obtained.

Such a PEN polymer can be produced by a known method. For example, it can be produced by polycondensing naphthalene-2,6-dicarboxylic acid or an ester-forming derivative thereof and ethylene glycol or an ester-forming derivative thereof in the presence of a catalyst. In the case of a PEN copolymer, it can be produced by adding a copolymer component to the above-mentioned polymer component and subjecting it to polycondensation.
It can also be produced by mixing an EN polymer in a molten state and causing a transesterification reaction.

The release film of the present invention improves the slipperiness,
In order to improve the winding property of the film, the surface roughness (Ra) of the base film needs to be 50 nm or more and less than 100 nm. If the surface roughness (Ra) is less than 50 nm, the winding property of the release film deteriorates, which is not preferable. On the other hand, if the surface roughness (Ra) is 100 nm or more, the resin sheet or the ceramic sheet manufactured using the release film is pinned. It is not preferable because a product defect such as a hole occurs.

As a method for adjusting the surface roughness (Ra) of the base film to the above range, a method of incorporating fine particles into a PEN polymer is generally used.

This method will be described in detail. An inorganic fine particle or an organic fine particle having an average particle diameter of 0.01 to less than 5 μm is coated on a base film having a surface roughness (Ra) of 50 nm.
Or more and less than 100 nm, for example, 0.005 to 10
%, Preferably 0.1% by weight.
It is preferable that the content be contained in the range of 01 to 5% by weight.

Specific examples of such fine particles include inorganic fine particles such as silica, alumina, kaolin, calcium carbonate, titanium oxide, barium sulfate, and carbon black, and organic fine particles such as a crosslinked acrylic resin, a crosslinked polystyrene resin, a melamine resin, and a crosslinked silicone resin. Are preferred.

Since the molecular chain of the PEN polymer is rigid and the stiffness of the film is higher than that of the polyethylene terephthalate polymer, the amount of the fine particles is limited to PET.
Even if the amount is less than that of the polymer, the lubricating property is good and sufficient winding property can be obtained.

Further, in addition to the fine particles, additives such as a stabilizer, an ultraviolet absorber, a flame retardant, and an antistatic agent can be added to the PEN polymer. A small amount of other thermoplastic resin (for example, 20% by weight or less, particularly 10% by weight or less)
It can also be blended.

The biaxially oriented PEN film in the present invention can be produced by a conventionally known method such as a sequential biaxial stretching method or a simultaneous biaxial stretching method. For example, in the sequential biaxial stretching method, a PEN polymer is sufficiently dried, and then an unstretched film is produced by a melt extrusion method. Then, the unstretched film is stretched at a temperature of 130 to 150 ° C. in a longitudinal direction by 2 to 6 times.
And then stretched in the transverse direction at a temperature of 120-150 ° C.
It can be manufactured by performing stretching up to 6 times and heat setting at a temperature of 220 to 255 ° C. for 5 seconds to 1 minute. The heat setting may be performed under limited shrinkage. At the time of melt extrusion, it is preferable to use an electrostatic adhesion method.

In order to further improve the heat-resistant deformation of the release film at around 110 ° C., it is preferable to heat-treat the film which has been biaxially stretched and heat-set at a temperature of 120 to 150 ° C. in a relaxed state.

In the release film of the present invention, the absolute value of the dimensional change under a stress of 150 gf / mm ^{2 at} 120 ° C. is 0.1 in both the film roll winding direction and the vertical direction.
200 ° C. in a state of not more than 3% and no stress,
The absolute value of the heat shrinkage after the treatment for 10 minutes is preferably 1.0% or less in both the film roll winding direction and the vertical direction.

When the absolute value of the dimensional change exceeds 0.3% or the absolute value of the heat shrinkage exceeds 1.0%, a resin sheet or a ceramic sheet is manufactured using a release film. In the process, there is a problem that the release film is deformed during the heat treatment.

The release film of the present invention has an elastic modulus of 1. in both the winding direction of the film roll and the vertical direction.
It is preferably in the range of 0 × 10 ^{11 to} 1.7 × 10 ¹¹ dyne / cm ² . The elastic modulus is 1.0 × 10 ¹¹ dyne
If it is smaller than / cm ² , burrs, warpage and the like are likely to occur in punching such as cutting. On the other hand, 1.7 × 10 ¹¹ dyne / c
If it is larger than m ² , the cutting proceeds more than necessary at the time of cutting, and it is difficult to cut into a predetermined shape.

The release film of the present invention preferably has an isotropic index of 0.6 to 1.5. Here, the isotropic index indicates a ratio of the elastic modulus in the film roll winding direction to the elastic modulus in the direction perpendicular to the film roll winding direction. If the isotropic index is less than 0.6 or greater than 1.5, the cutting proceeds more than necessary at the time of cutting such as punching, and it may be difficult to perform predetermined cutting.

In order to make the isotropic index fall within the above range, it is preferable that the stretching ratio in the above-mentioned film roll winding direction and in the vertical direction is the same.

The thickness of the biaxially oriented PEN film used in the present invention is not particularly limited, but is preferably from 10 to 200 μm.

The release film of the present invention has a side length of 21
There is no foreign matter having a maximum diameter of 25 μm or more in the base film per area (area 310.8 cm ² ) of 0 mm and a side having a length of 148 mm and a side perpendicular thereto, and 10 or less foreign matters having a maximum diameter of 5 μm or more and less than 25 μm. Needs to be When the abundance of foreign substances exceeds the above range, using a release film, when manufacturing a resin sheet or a ceramic sheet,
These are undesirable because they cause product defects such as pinholes.

In order to control the number of foreign substances in the above range, a method of removing foreign substances using a filter when melt-extruding a PEN polymer in a film forming process of a biaxially oriented PEN film, a method of adding lubricant particles to be added to the PEN polymer. A known foreign matter reduction method such as a method of previously removing coarse particles (including agglomerated particles) having a particle size of 5 μm or more using an air classifier or the like can be used.

Here, the foreign material in the present invention is a foreign material that can be optically detected by a visual inspection by the cross Nicol method. For example, the inorganic or organic lubricant compounded when manufacturing the PEN film is agglomerated. And coarse,
Foreign substances generated or mixed in the process of manufacturing the PEN film can be mentioned.

The size of the foreign matter in the present invention is measured as follows. That is, the foreign matter in the biaxially oriented PEN film optically detected in the visual inspection by the crossed Nicols method is separately observed with transmitted light using an optical microscope, and the part observed as an optically abnormal area is observed. The maximum diameter is the size of the foreign matter. For example, when a film is stretched, a void (void) is formed around a foreign substance or the like which is agglomerated by aggregating a lubricant. If the cavity is observed as an optically abnormal range, the size of the foreign substance is reduced. Include in. The number of foreign substances was measured by measuring the sample film to a size (length 210 mm × length) based on the standard base paper size A5 of Japanese Industrial Standards.
148 mm in width: an area of 310.8 cm ² ) is cut out, and the number of foreign substances in the entire area of the film is measured.

In the present invention, a release layer is preferably provided on at least one side of the biaxially oriented PEN film.
Examples of the component forming the release layer include a silicone resin, a fluororesin, and an aliphatic wax. Further, depending on the type of the resin sheet or the ceramic sheet, the release layer may not be provided.

The components forming such a release layer may be blended with various known additives within a range not to impair the object of the present invention. Examples of the additive include an ultraviolet absorber, a pigment, and an antifoaming agent.

The release layer can be applied by applying a coating solution containing a component forming the release layer to a biaxially oriented PEN film, and drying by heating to form a coating film.
The heating conditions are 80 to 160 ° C. for 10 to 120 seconds,
In particular, it is preferably at 120 to 150 ° C. for 20 to 60 seconds. As the coating method, any known method can be used, and examples thereof include a roll coater method and a blade coater method.

In the present invention, it is preferable to provide an adhesive layer between the base film and the release layer in order to enhance the adhesion between the base film and the release layer. As a component forming the adhesive layer, for example, when the release layer is a silicone resin layer, a silane coupling agent is preferable. Those represented by the general formula Y-Si-X ₃ is more preferred as the silane coupling agent. Here, Y is, for example, an amino group,
X represents a functional group represented by an epoxy group, a vinyl group, a methacryl group, a mercapto group and the like, and X represents a hydrolyzable functional group represented by an alkoxy group. The thickness of such an adhesive layer is 0.
The range is preferably from 01 to 5 μm, particularly preferably from 0.02 to 2 μm. When the thickness of the adhesive layer is within the above range, the adhesion between the base film and the release layer becomes good, and the base film provided with the adhesive layer is difficult to block, so that there is an advantage that a problem does not easily occur in handling the release film. is there.

[0052]

The present invention will be further described below with reference to examples. In addition, each characteristic value was measured by the following method.

(1) Surface Roughness (Ra) The film surface was measured using a stylus type surface roughness meter (Surfcoder 30C, manufactured by Kosaka Laboratory Co., Ltd.) under the conditions of a needle radius of 2 μm and a stylus pressure of 30 mg. Was scanned, the displacement of the film surface was measured, and the surface roughness curve was recorded. From this surface roughness curve, extract the measurement length (L) in the direction of its center line,
It was calculated by the following equation from a surface roughness curve (Y = f (x)) when the X axis was the scan distance and the Y axis was the surface displacement.

[0054]

(Equation 2)

(2) Dimensional change (with load) A strip-shaped film cut out in a measuring direction of 30 mm or more and a width of 4 mm was set on a jig of a TMA (thermal stress strain measuring device, TMA / SS120C manufactured by Seiko Denshi Kogyo Co., Ltd.). Attach so that the distance between the chucks is 10 mm.
Applying a stress of 0 gf / mm ² , heating from room temperature at a heating rate of 5 ° C./min, and measuring a dimensional change when the temperature reaches 120 ° C. in the winding direction of the film roll and in the vertical direction thereof, and It was calculated and found. Absolute value of dimensional change rate = | Dimension change / Distance between chucks | ×
100 (%)

(3) Heat shrinkage (no load) A sample was measured in a measuring direction at a length of 350 mm or more and a width of 10 mm.
The sample was cut into strips, marked with a mark of 300 mm in length, kept in a constant-temperature room conditioned at 23 ° C. × 60% RH for a free length of 24 hours or more, and then read with a scanning microscope. Read (L ₀ ). Next, after keeping the strip-shaped sample in an air oven set at a predetermined temperature (200 ° C.) for a predetermined length of time (30 minutes), the sample is again heated to 23 ° C. ×
After maintaining at a constant temperature and humidity of 60% RH for 24 hours or more with a free length, the distance (L ₁ ) between the gauge points was read and calculated by the following formula. The measurement was performed in the direction of winding the film roll,
The tests were performed separately in the vertical direction. Absolute value of heat shrinkage = | (L ₁ −L ₀ ) / L ₀ | × 100
(%)

(4) Punching Property (Cutting Property) A polyvinyl alcohol resin dissolved in water as a model paint is dried to a thickness of 30 μm on the prepared release film.
m, and water was dried and evaporated. Thereafter, a 15 cm square metal mold was used to observe the burrs of the punched edges and the bending of the corners, and judgment was made according to the following criteria.・ ・ ・: No burr or bending occurs. Δ: Fine burrs are generated or the film is bent, and the resin film is slightly elongated. X: Bad cutting, strong burrs generated, or resin film cannot be cut sufficiently.

(5) Transportability A metal roll was provided on the release layer, and a rubber roll was provided on the back of the release layer, and nip was performed under a load of 100 g / cm. At this time, by transporting the release film at 10 m / min,
The occurrence of snagging and wrinkling at the nip was observed and judged according to the following criteria.・ ・ ・: The sheet can be conveyed without being caught or wrinkled in the nip portion. Δ: Wrinkles sometimes occur at the nip. ×: Scratching occurs at the nip, causing wrinkles and causing difficulty in transportation.

(6) Number of Foreign Particles The sample film was sized according to the standard size A5 of Japanese Industrial Standards (length 209 to 210 mm × width 148 to 1).
49 mm: area of about 310 cm ² ), and the whole area of the film was visually inspected for foreign substances by the crossed Nicols method. Next, the detected foreign matter in the sample film was observed with transmitted light using an optical microscope, and the maximum diameter of a portion observed as an optically abnormal range was defined as the size of the foreign matter. When a cavity (void) existing around the foreign matter is observed as an optically abnormal range, it is included in the size of the foreign matter. Further, the size of the foreign material was divided into those having a size of 25 μm or more and those having a size of 5 μm or more and less than 25 μm, and the number of foreign materials per A5 plate was measured.

Example 1 Average particle size of 5 using an air classifier
A PEN polymer having an intrinsic viscosity of 0.60 containing 0.25% by weight of spherical silica particles having an average particle diameter of 0.3 μm from which coarse particles of μm or more were removed was melted by an extruder, and maintained at 40 ° C. from a die. Extruded onto a rotating cooling drum
The molten polymer was brought into close contact with a rotary cooling drum using an electrostatic adhesion method and rapidly cooled to obtain an unstretched film. Next, the unstretched film was stretched 3.7 times in the machine direction and 3.7 times in the transverse direction, and heat-set at 230 ° C. to obtain a biaxially oriented PEN film having a thickness of 50 μm.

On one surface of the biaxially oriented PEN film, the following coating solution was applied at a coating amount of 6 g / m ² (wet), and heated and dried at 140 ° C. for 1 minute to cure the release layer. A release film having a thickness of 0.1 μm was prepared.
The coating liquid was obtained by dissolving an addition-reaction-type curable silicone composed of polydimethylsiloxane having a vinyl group and dimethylhydrogensilane in a mixed solvent of methyl ethyl ketone, methyl isobutyl ketone and toluene, and further curing the silicone resin with the curable silicone. A solution having a solid content ratio of 10% by weight with respect to silicone was added to form a solution having a total solid content of 2%, and a platinum catalyst was added to this solution to prepare a solution. Table 1 shows the characteristics of the release film.

Example 2 Intrinsic viscosity containing 0.15% by weight and 0.10% by weight of spherical silica particles having an average particle diameter of 0.3 μm and 0.4 μm, the particle diameters of which were adjusted in the same manner as in Example 1. Is melted by an extruder, extruded from a die onto a rotating cooling drum maintained at 40 ° C., and the molten polymer is brought into close contact with the rotating cooling drum using an electrostatic adhesion method and rapidly cooled. It was a stretched film. Next, this unstretched film was stretched 3.7 times in the machine direction and then 3.8 times in the transverse direction, and heat-set at 230 ° C. to obtain a biaxially oriented PEN film having a thickness of 50 μm. A release layer was provided on one surface of the biaxially oriented PEN film in the same manner as in Example 1 to prepare a release film. Table 1 shows the characteristics of the release film.

Example 3 An intrinsic viscosity of 0.6% containing 0.1% by weight of true spherical silica particles having an average particle size of 0.15 μm was 0.6%.
The PEN polymer of No. 2 was melted in an extruder and 4
It was extruded onto a rotating cooling drum maintained at 0 ° C., and the molten polymer was brought into close contact with the rotating cooling drum using an electrostatic adhesion method, and rapidly cooled to obtain an unstretched film. Next, this unstretched film is stretched by 5.2 times in the machine direction and then 2.8 times in the transverse direction, and is heat-set at 225 ° C. to have a thickness of 50 times.
A μm biaxially oriented PEN film was obtained. This biaxial orientation P
A release layer was applied to one surface of the EN film in the same manner as in Example 1 to prepare a release film. Table 1 shows the characteristics of the release film.

Comparative Example 1 An intrinsic viscosity of 0.6% containing 0.1% by weight of spherical silica particles having an average particle diameter of 0.15 μm was 0.6.
The PEN polymer of No. 2 was melted in an extruder and 4
It was extruded onto a rotating cooling drum maintained at 0 ° C., and the molten polymer was brought into close contact with the rotating cooling drum using an electrostatic adhesion method to be rapidly cooled to obtain an unstretched film. Next, the unstretched film is stretched 3.6 times in the machine direction and 3.7 times in the transverse direction, and is heat-set at 220 ° C. to have a thickness of 50 times.
A μm biaxially oriented PEN film was obtained. This biaxial orientation P
A release layer was applied to one surface of the EN film in the same manner as in Example 1 to prepare a release film. Table 1 shows the characteristics of the release film.

Comparative Example 2 A release film was prepared in the same manner as in Example 2 except that the spherical silica particles in Example 2 were replaced with an average particle diameter of 10 μm and a content of 0.3% by weight. Table 1 shows the characteristics of the release film.

Comparative Example 3 An intrinsic viscosity of 0.6% containing 0.1% by weight of true spherical silica particles having an average particle diameter of 0.15 μm was 0.6.
The polyethylene terephthalate polymer of No. 2 is melted by an extruder, extruded from a die onto a rotating cooling drum maintained at 40 ° C., and the molten polymer is adhered to the rotating cooling drum using an electrostatic adhesion method and rapidly cooled to obtain an unstretched film. And
Next, this unstretched film was stretched 3.5 times in the machine direction and then 3.3 times in the transverse direction, and heat-set at 225 ° C. to obtain a biaxially oriented PET film having a thickness of 50 μm. Example 1 was placed on one side of this biaxially oriented PET film.
A release layer was applied in the same manner as described above to prepare a release film. Table 1 shows the characteristics of the release film.

[0067]

[Table 1]

As is clear from Table 1, the release films of the present invention shown in Examples have excellent dimensional stability during heat treatment, and excellent transportability and cutting properties.

[0069]

According to the present invention, a uniform surface can be obtained in the molding of various resin sheets, resin coatings, ceramic sheets, etc., the heat deformation during the heat treatment is very small, and even when the sheet is cut. A release film free from burrs and the like can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F071 AA26 AA45 AA67 AA71 AB18 AD02 AF20Y AF54Y AF61Y AH19 BA01 BB06 BB08 BC01 BC10 BC16 4F100 AJ11B AJ11C AK18B AK18C AK42A AK42K AK52B JAA BA03 BA03 BA06 BA03 BA03 BA03 BA03 JK14 JK14A JL00 YY00A 4J002 BC032 BG022 CC182 CF081 CP032 DA036 DE136 DE146 DE236 DG046 DJ016 DJ036 FD016 GF00

Claims (4)

[Claims] 1. A surface roughness (Ra) of 50 nm or more and 100 or more.
A release film having a base film of a biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film having a size of less than 10 nm and a width of 210 mm on one side and 148 mm on a side perpendicular thereto (area 310.m). 8cm
² ) A release film characterized in that no foreign matter having a maximum diameter of 25 µm or more is present in the base film, and that no more than 10 foreign matters have a maximum diameter of 5 µm to less than 25 µm. 2. The absolute value of the dimensional change rate under a stress of 150 gf / mm ^{2 at} 120 ° C. is 0.3% or less in both the film roll winding direction and the vertical direction, and is 200 ° C. in a state where no stress is applied. The release film according to claim 1, wherein the absolute value of the heat shrinkage after the treatment for 10 minutes is 1.0% or less in both the film roll winding direction and the vertical direction. 3. The release film has an isotropic index of 0.6 to 0.6.
1.5 and an elastic modulus of 1.0 × 10 ^{11 to} 1.7 × 1 in both the winding direction of the base film roll and the vertical direction thereof.
The release film according to claim 1, wherein the release film has a value of 0 ¹¹ dyne / cm ² . 4. The release film according to claim 1, wherein at least one selected from a silicone resin, a fluororesin, and an aliphatic wax is laminated on at least one surface of the base film.