JP6458353B2 - Release polyester film - Google Patents

Description

  The present invention relates to a release film suitable for a green sheet. Specifically, the release film is a heavy release film containing a cellulose derivative in an addition-type silicone release layer and has a small change in peel force over time. In addition, the present invention relates to a release polyester film for green sheets which has no burrs or the like when punching through-holes when a ceramic substrate is produced by a multilayer lamination method of green sheets, and has improved punchability.

  In the field of manufacturing semiconductor integrated circuits, fine patterning and multilayering are required as the density increases. Through-holes are required to increase the number of layers, and in order to increase the density, it is necessary to make the through-holes narrower along with further fine patterning.

  The through hole is filled with conductive paint and becomes a conduction circuit between laminations, but when using a polyester film as a release film, burrs occur when punching through holes, and good through holes cannot be obtained There is. In other words, the generation of burrs hinders the filling of the conductive paint particularly in the case of a narrow through hole, and increases the defect rate. Another problem is that the generated burrs break the green sheet and change the size of the through hole.

  By the way, it is known that a release film containing a cellulose derivative in a silicone release layer has a writing property, and by adjusting the content of the cellulose derivative, a particularly heavy release film can be obtained. Although it is possible, the heavy release release film obtained by containing the cellulose derivative in this way has a problem that the silicone component is easily rearranged in the release layer and light release with time. Yes.

In addition, in a release film having a release layer of addition-type silicone, R ₃ SiO _1/2 (wherein R is a monovalent hydrocarbon group) and SiO _{4 /} Although the MQ resin consisting of siloxane units represented by ₂ known to be incorporated in the silicone composition by simply adding the MQ resin in addition type silicone is possible to obtain a release film of extremely peeling heavy region It is difficult, and when MQ resin is added excessively, there arises a problem that the release layer is delaminated with time, or that the appearance of the release layer is poor.

  For ceramic green sheets, there is an increasing demand for thick sheets and green sheets that have less tackiness with fewer organic components, and have a stable heavy release mold release layer. Therefore, there is a great need for a release polyester film for a green sheet having improved punchability.

Japanese Patent Laid-Open No. 1-215857 JP-A-9-87594 JP-A-10-86304

Silicon catalog for Shin-Etsu silicone release paper (Shin-Etsu Chemical Co., Ltd.)

  The present invention has been made in view of the above circumstances, and the problem to be solved is when producing a ceramic substrate by a green sheet multilayer lamination method having a heavy release layer having a small change in peel force over time. An object of the present invention is to provide a release polyester film for a green sheet that is free of burrs and the like when punching through holes.

  As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by a release polyester film having a release layer having a specific configuration, and have completed the present invention.

  That is, the gist of the present invention is a laminated polyester film that is a film comprising at least two layers of polyester in which a base polyester film is laminated by coextrusion and that simultaneously satisfies the following formulas (1) to (3): The release polyester film is characterized by having a release layer containing a cellulose derivative (A), an addition reaction type silicone (B), an MQ resin (C), and a catalyst on at least one surface thereof.

0.53 ≦ [η] ≦ 0.60 (1)
0.1 ≦ d50 ≦ 1 (2)
5 ≦ WA ≦ 20 (3)
(In the above formula, [η] is the intrinsic viscosity of the substrate-laminated polyester film, d50 is the average particle size (μm) of particles contained in at least one layer of the substrate-laminated polyester film, and WA is in the layer of the particles) Content (% by weight)

  According to the present invention, there is a heavy release layer that has a small change in peel force over time, and there is no generation of burrs when punching through holes when creating a ceramic substrate by a green sheet multilayer lamination method. A release polyester film for green sheets with good properties can be obtained, and its industrial value is high.

  In the present invention, the base material laminated polyester film is a film extruded by a so-called coextrusion method in which all layers are melt extruded from an extrusion die, and are usually longitudinal and lateral directions after being extruded. The film is oriented in the biaxial direction.

  In the base material laminated polyester film of the present invention, the polyester constituting each laminated layer may be a homopolyester or a copolyester. In the case of a homopolyester, the polyester is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like.

  On the other hand, the copolymer polyester is a copolymer containing a third component of 30 mol% or less. Examples of the dicarboxylic acid component of the copolymer polyester include isophthalic acid, terephthalic acid phthalate, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acids (for example, P-oxybenzoic acid). Or 2 or more types are mentioned, As a glycol component, 1 type, or 2 or more types, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, are mentioned.

In the present invention, the intrinsic viscosity of the base material laminated polyester film constituting the release polyester film needs to satisfy the following formula (1): 0.53 ≦ [η] ≦ 0.60 (1)
(In the above formula, [η] represents the intrinsic viscosity of the base material laminated polyester film)

  In the present invention, when the intrinsic viscosity of the base material laminated polyester film exceeds 0.60, the effect of improving the punchability of the green sheet is insufficient, whereas when the intrinsic viscosity is less than 0.53, film formation is difficult. The situation is unpreferable for practical use.

In the present invention, it is necessary to contain particles in at least one of the layers constituting the base polyester film. Regarding the average particle size of the particles and the content thereof, the following formulas (2) and (3) must be satisfied at the same time.
0.1 ≦ d50 ≦ 1 (2)
5 ≦ WA ≦ 20 (3)
(In the above formula, d50 is the average particle size (μm) of particles contained in at least one layer of the substrate-laminated polyester film, and WA is the content (% by weight) of the particles in the layer)

  When the average particle size of the contained particles is less than 0.1 μm, the particles are likely to aggregate in the slurry. On the other hand, when adding particles with an average particle size exceeding 1 μm, the surface roughness of the layer to which the particles are added is It becomes rough and the surface roughness of the layer on the side where the release layer is provided is roughened, and the surface of the resulting green sheet is difficult to become smooth.

  When the amount of the contained particles is less than 5% by weight, the elongation rate at break of the obtained release polyester film is high, and as a result, burrs are easily generated when punching through holes. On the other hand, when the amount of added particles exceeds 20% by weight, the mechanical strength of the film decreases.

  As a kind of particle | grains contained in a base material laminated polyester film, particles, such as a silica, a calcium carbonate, a kaolin, a titanium oxide, are mentioned. The method of blending the particles with the polyester is not particularly limited, and a known method can be adopted. For example, it can be added at any stage for producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or after the end of the ester exchange reaction and before the start of the polycondensation reaction. The polycondensation reaction may proceed. Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a method of blending dried particles and a polyester raw material using a kneading extruder Done.

On the other hand, it is preferable that the amount of particles added to the substrate-laminated polyester film layer on the side where the release layer of the release polyester film referred to in the present invention is provided is less than 1% by weight. When the amount of particles added to the layer exceeds 1% by weight, the surface of the release layer may not be smooth when a release layer is provided thereon. In the present invention, the center line average roughness (Ra) on the surface of the release layer preferably satisfies the following formula (4).
0.03 ≦ Ra ≦ 0.1 (4)

  When the release polyester film of the present invention is used for producing a green sheet, if the center line average roughness Ra of the surface provided with the release layer is less than 0.03 μm, the stability of the film forming property of the base laminated polyester film is improved. Tend to lack. On the other hand, when the Ra exceeds 0.1 μm, the smoothness of the finished green sheet surface may not be sufficient. When the release layer is provided only on one surface, Ra on the surface on which the release layer is not provided may exceed 0.1 μm, and when the release layer is provided on both surfaces, Ra preferably satisfies the above formula (5), and both values are not necessarily the same.

  The release polyester film of this invention should just be the thickness which can form a base material laminated polyester film, and is 25-350 micrometers in total thickness, Preferably it is the range of 50-188 micrometers. The thickness of the polyester layer on the side where the release layer is provided is 50% or less, preferably 30% or less of the total film thickness when the particle content is reduced in consideration of the smoothness of the release layer surface. More preferably, 10% or less is suitable for use. If the content exceeds 50%, the particle content of the layer on the side where the release layer is provided is small, so that the resulting release polyester film itself has a high elongation at break, and burrs are generated when punching through holes. It tends to be easy to do.

  Next, although the manufacturing method of the laminated biaxially stretched polyester film in this invention is demonstrated concretely, the film of this invention is not limited to the following manufacture examples at all. That is, using the polyester raw material described above, using a plurality of extruders, a multi-layer multi-manifold die or a feed block, laminating each polyester and extruding a multi-layer molten sheet from the die, and using a cooling roll A method of cooling and solidifying to obtain an unstretched sheet is preferred. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed.

  Next, the obtained unstretched film is stretched biaxially and biaxially oriented. That is, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, stretching is performed in a direction orthogonal to the first-stage stretching direction. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 115 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature in the range of 130 to 250 ° C. under a relaxation of 30% or less to obtain a biaxially stretched film.

  A so-called in-line coating can be applied to treat the film surface during the stretching process. Although it is not limited to the following, for example, after the first stage of stretching is completed, before the second stage of stretching, improvement of antistatic property, slipperiness, adhesion, etc., secondary workability improvement, etc. For this purpose, a coating treatment of an aqueous solution, an aqueous emulsion, an aqueous slurry or the like can be performed.

  In the above stretching, a method of performing unidirectional stretching in two or more stages can also be used. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges. The unstretched sheet can be simultaneously biaxially stretched so that the area magnification is 10 to 40 times. Furthermore, it may be stretched again in the longitudinal and / or transverse direction before or after performing the heat treatment, if necessary. Moreover, various stabilizers, ultraviolet absorbers, lubricants, pigments, antioxidants, plasticizers, and the like may be added to the polyester film. In the base material laminated polyester film of the present invention, the elongation at break (%) in the β-axis and γ-axis directions preferably satisfies the following formula (5).

100 ≦ EBβ + EBγ ≦ 200 (5)
(In the above formula, EBβ and EBγ are the elongation at break (%) in the β-axis and γ-axis directions of the film, respectively, and Ra represents the centerline average roughness (μm) of the release layer surface)

  When the total elongation at break in the β-axis and γ-axis directions is less than 100%, the film itself is brittle, and the film tends to be easily broken when punching through holes. On the other hand, if it exceeds 200%, burrs may occur when punching through holes. In addition, it is preferable for applications that the difference between the absolute values of the elongation at break in the γ-axis direction and the β-axis direction is in the range of 0 to 40% after satisfying the above expression (5).

  Next, a method for providing a release layer of the release polyester film of the present invention will be described. In the release layer of the present invention, a cellulose derivative (A), an addition reaction type silicone (B), an MQ resin (C), In addition, the inclusion of a catalyst is an essential requirement.

  These are generally blended once as a solvent composition such as toluene or toluene / MEK, and then provided on the base polyester film by coating, which is also preferable in the present invention.

  As the cellulose derivative (A), methylcellulose, ethylcellulose, and acetylcellulose derivatives can be appropriately used as those that exhibit writing properties and at the same time make the release layer heavy release.

  The addition reaction type silicone (B) is a polyorganosiloxane containing an alkenyl group in the molecule and a polyorganosiloxane containing a hydrosilyl group (Si—H) in the molecule, both of which are at least 2 in one molecule. It has one or more alkenyl groups and hydrosilyl groups. The polyorganosiloxane that forms the main chain or skeleton of the polyorganosiloxane is not particularly limited, and examples thereof include polydimethylsiloxane, polydiethylsiloxane, and polydiphenylsiloxane. Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, and a hexenyl group. Among them, a vinyl group and a hexenyl group are preferable.

MQ resin (C) includes a siloxane unit represented by M unit [R ₃ SiO _1/2 (wherein R is a monovalent hydrocarbon group)] and a siloxane unit represented by Q unit [SiO _4/2 ]. It is a silicone resin. The MQ resin may be used alone or in combination of two or more, and may be a D unit [R ₂ SiO _2/2 (wherein R is a monovalent hydrocarbon)] or a T unit [RSiO _3/2 (wherein R May contain a monovalent hydrocarbon)]. Moreover, you may have functional groups, such as an alkenyl group, in a molecule | numerator.

  In the MQ resin (C), the total proportion of M units and Q units is preferably 70% or more, more preferably 80% or more, of all the structural units (100%). Further, the ratio of the M unit and the Q unit is not particularly limited, but is preferably M unit: Q unit (molar ratio), 0.1: 1.0 to 1.3: 1.0, more preferably 0.5: 1.0 to 1.0: 1.0.

  As an example of a concrete commercial item of MQ resin (C), brand name "KS-3800" (made by Shin-Etsu Chemical Co., Ltd.), brand name "X-92-183" (made by Shin-Etsu Chemical Co., Ltd.), for example. ), Trade name “SD7292” (manufactured by Toray Dow Corning Co., Ltd.), trade name “BY24-843” (manufactured by Toray Dow Corning Co., Ltd.), and the like.

  In the present invention, the cellulose derivative (A) is preferably contained in an amount of 20% by weight or more based on the entire release layer, but if this is not contained in an amount of 20% by weight or more, a sufficient release layer can be obtained. This is because the effect of the present invention may not be exhibited.

  In addition, the initial normal peel force is preferably 400 mN / cm or more, but if it is less than 400 mN / cm, the effect of the present invention may not be obtained.

  The weight ratio ((C) / (B)) of the addition reaction type silicone (B) and the MQ resin (C) is preferably in the range of 0.2 to 2, more preferably 0.25 to 1.5. More preferably. When (C) / (B) is less than 0.2, the light release over time may not be sufficiently suppressed. On the other hand, when (C) / (B) is larger than 2, heavy peeling over time is observed, and the appearance of the obtained release layer is caused by the poor film increasing property of MQ resin (C). It can be bad.

  The catalyst used in the release layer of the present invention is usually an addition reaction catalyst and is not particularly limited as long as it is used. For example, a platinum-based catalyst is generally used as a catalyst for addition reaction type silicone. Preferably raised. The platinum-based catalyst is preferably at least one platinum-based catalyst selected from chloroplatinic acid, platinum olefin complexes, and chloroplatinic acid olefin complexes. Among them, a platinum olefin complex containing a siloxane structure is preferable, and a Karstedt catalyst (see U.S. Pat. Nos. 3,715,334 and 3,775,452) is more preferable in terms of excellent silicone curability.

  The amount of the catalyst in the release layer is not particularly limited, but when it is a platinum-based catalyst, it is preferably 10 to 1000 ppm by weight in terms of platinum with respect to the total solid content. If it is less than 10, the reaction is slow and the curing tends to be insufficient, and if it exceeds 1000, the pot life of the solvent composition may be shortened.

  In the present invention, a coating layer such as an adhesive layer, an antistatic layer or a coating layer may be provided on the surface where the release layer is not provided, and the polyester film is subjected to a surface treatment such as corona treatment or plasma treatment. May be applied.

  In the present invention, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating and the like can be used as a method for providing a release layer on the polyester film. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

  In the present invention, the curing conditions for forming the release layer on the substrate-laminated polyester film are not particularly limited. When the release layer is provided by off-line coating, usually at 100 to 200 ° C. for 15 seconds. The heat treatment should be performed for ˜1 minute, preferably 120 to 180 ° C. for 20 to 40 seconds. Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. In addition, a conventionally well-known apparatus and an energy source can be used as an energy source for hardening by active energy ray irradiation.

The coating amount of the release layer is usually from 0.005 to 1 g / m ² , preferably from 0.005 to 0.5 g / m ² , more preferably from 0.01 to 0.2 g / m from the viewpoint of coatability. ^{There are two} ranges. If the coating amount is less than 0.005 g / m ² , the coating property may be less stable and it may be difficult to obtain a uniform coating film. On the other hand, when the coating is thicker than 1 g / m ² , the coating layer adhesion and curability of the release layer itself may be lowered.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example. In the examples and comparative examples, “parts” means “parts by weight” as a solid part. The evaluation method used in the present invention is as follows.

(1) Measuring method of average particle diameter (d50) A film piece was fixed and molded with an epoxy resin, then cut with a microtome, and a longitudinal section of the film was observed with a transmission electron microscope. For the particles present in the film, the maximum diameter is obtained by a line drawn parallel to the film surface and is set as Dmax, and the maximum diameter perpendicular to the line is set as Dmin. Was calculated.
Particle diameter (diameter) = (Dmax + Dmin) / 2
The average particle size of the particle group was determined for the above particle size for at least 100 particles, and the average particle size was determined in terms of the volume fraction of the equivalent sphere equivalent of the particle size of 50%.

(2) Intrinsic Viscosity [η] Measurement Method 1 g of sample film was dissolved in 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) and measured at 30 ° C.

(3) Ceramic slurry coating property evaluation The state immediately after coating the ceramic slurry on the release film was visually observed and evaluated according to the following criteria.
<Criteria>
○: Good coatability △: Uneven coating occurs (a level that does not cause a problem in practice)
×: Coating unevenness occurred (practical problem level)

(4) Through-hole punchability evaluation Using “2HOLE PUNCH No.35” manufactured by Lion Corporation and punching out the sample film, the punched portion was obtained with a digital microscope “VH-6200” manufactured by Keyence Corporation. Observation was performed at 200 times and the determination was made by the following three-level evaluation.
<Criteria>
◎: No burr observed ◯: Almost no burr observed △: Burr observed (practical level)
×: Burr is observed (practically problematic level)

(5) Determination of γ-axis and β-axis of sample film Nomura Shoji Co., Ltd. “SONIC SHEET TESTERSST-250” was used to place the sample film on a turntable and measured while rotating the propagation velocity in the surface direction. . From the measurement results, the direction in which the propagation velocity showed the maximum value was taken as the γ axis, and the direction perpendicular to it was taken as the β axis.

(6) Elongation rate evaluation method at break Using a tensile tester ("INTESCO model 2001 type" manufactured by Intesco Co., Ltd.) at a temperature of 23 degrees and a humidity of 50% RH, the distance between chucks is 50 mm and the width is 10 mm. The sample film was pulled at a rate of 500 mm / min, and the tensile elongation at break was determined from the stress-strain curve according to the following formula. In the formula, L represents the distance between chucks at the time of fracture, and L0 represents the distance between chucks.
Tensile elongation at break (%) = [(L−L0) / L0] × 100

(7) Surface roughness (Ra) evaluation method It was set as surface roughness with the centerline average roughness Ra (micrometer) of a mold release surface. The surface roughness was measured according to JIS-B-0601-1982 using a surface roughness measuring machine (SE-3F) manufactured by Kosaka Laboratory. However, the cut-off value was 80 μm and the measurement length was 2.5 mm.

(8) Appearance of release layer The appearance of the release layer was evaluated by visually observing the full width (1 m) x 2 m length by reflection under a fluorescent lamp.
<Criteria>
○: Good △: Some unevenness ×: There is unevenness

(9) Evaluation of Normal Peeling Force (F) of Release Polyester Film After pasting one side of a double-sided adhesive tape (“Nitto Denko“ No. 502 ”) on the release layer surface of the sample film, a size of 50 mm × 300 mm Then, the peel strength after standing at room temperature for 1 hour is measured. For the peeling force, a tensile tester (“Intesco model 2001 type” manufactured by Intesco Co., Ltd.) was used, and 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min.

In addition, after producing a release polyester film, the value after 1 day at room temperature is taken as the initial value (F0), and compared with the value after the same 6 months (F1). Asked.
Rate of change% = (F1-F0) / F0 × 100

Production Example 1 (Polyester A):
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, and the temperature is raised while heating and methanol is distilled off. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, after adding 10 parts of silica particles having an average particle diameter of 1 μm, 0.04 part of phosphoric acid, and 0.04 part of antimony trioxide, the temperature was 280 ° C. and the pressure was 15 mmHg in 100 minutes.
After that, the pressure was gradually reduced to a final value of 0.05 mmHg. After 4 hours, using the correlation between the torque of the stirring blade of the polymerization tank and the degree of polymerization, the reaction was stopped when it was determined that the torque of the stirring blade reached the target intrinsic viscosity, and the system was at atmospheric pressure. The polyester A was obtained. The silica particle content of polyester A was 10% by weight.

Production Example 2 (Polyester B):
Polyester B was obtained in the same manner as in Production Example 1 except that 10 parts of silica particles having an average particle diameter of 1 μm were not added in Production Example 1.

Production Example 3 (Polyester C):
In Production Example 2, 70 parts of the obtained polyester B and 30 parts of titanium oxide particles having an average particle diameter of 1.0 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyester C. The content of titanium oxide particles of polyester C was 30% by weight.

Production Example 4 (Polyester D):
In Production Example 2, 95 parts of the obtained polyester B and 20 parts of calcium carbonate particles having an average particle size of 0.1 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyester D. The content of calcium carbonate particles of polyester D was 20% by weight.

Production Example 5 (Polyester E):
In Production Example 2, 80 parts of the obtained polyester B and 5 parts of calcium carbonate particles having an average particle diameter of 1 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyester E. The content of calcium carbonate particles in polyester E was 5% by weight.

Production Example 6 (Polyester F):
In Production Example 1, the same procedure as in Production Example 1 was conducted except that 10 parts of titanium oxide particles having an average particle diameter of 0.5 μm were added instead of adding 10 parts of silica particles having an average particle diameter of 1 μm in the obtained polyester A. Polyester F was obtained. The content of titanium oxide particles in polyester F was 10% by weight.

Production Example 7 (Polyester G):
In Production Example 1, the same procedure as in Production Example 1 was conducted except that 20 parts of titanium oxide particles having an average particle diameter of 0.05 μm were added instead of adding 10 parts of silica particles having an average particle diameter of 1 μm in the obtained polyester A. Polyester G was obtained. The content of titanium oxide particles in polyester G was 20% by weight.

Production Example 8 (Polyester H):
In Production Example 1, the same procedure as in Production Example 1 was conducted except that 10 parts of titanium oxide particles having an average particle diameter of 1.5 μm were added instead of adding 10 parts of silica particles having an average particle diameter of 1 μm in the obtained polyester A. Polyester H was obtained. The content of titanium oxide particles in polyester H was 10% by weight.

Production Example 9 (Polyester I):
In Production Example 1, the same procedure as in Production Example 1 was conducted, except that 3 parts of titanium oxide particles having an average particle diameter of 0.5 μm were added instead of adding 10 parts of silica particles having an average particle diameter of 1 μm in the obtained polyester A. Polyester I was obtained. The content of titanium oxide particles in polyester I was 3% by weight.

Production Example 10 (Polyester J):
In Production Example 1, the same procedure as in Production Example 1 was conducted except that 15 parts of titanium oxide particles having an average particle diameter of 0.5 μm were added instead of adding 10 parts of silica particles having an average particle diameter of 1 μm in the obtained polyester A. Polyester J was obtained. The content of titanium oxide particles in polyester J was 15% by weight, and the intrinsic viscosity [η] was 0.50.

<Manufacture of substrate laminated polyester film>
Production Example 11 (Polyester film F1):
After blending polyester B and polyester A separately, they were dried in an inert gas atmosphere at 180 ° C. for 4 hours, melt extruded at 290 ° C. with a separate melt extruder, and these polymers were merged in a feed block. The laminated unstretched sheet was obtained by laminating and cooling and solidifying on a cooling roll whose surface temperature was set to 40 ° C. using an electrostatic application adhesion method. The obtained sheet was stretched 3.8 times in the longitudinal direction at 85 ° C. Next, the film was guided to a tenter and stretched in the transverse direction 3.6 times at 125 ° C., and then heat-set at 230 ° C. to obtain a laminated polyester film 75 μm. The layer configuration was B / A, and the thickness of each layer was 20/55 (μm).

Production Example 12 (Polyester film F2):
In Production Example 11, production was carried out in the same manner as in Production Example 11 except that polyester C was used instead of polyester A to obtain a laminated polyester film of 75 μm. The layer configuration was B / C, and the thickness of each layer was 10/65 (μm).

Production Example 13 (Polyester film F3):
In Production Example 11, production was carried out in the same manner as in Production Example 11 except that polyester D was used instead of polyester A to obtain a laminated polyester film of 75 μm. The layer configuration was B / D, and the thickness of each layer was 5/70 (μm).

Production Example 14 (Polyester film F4):
In Production Example 11, production was carried out in the same manner as in Production Example 11 except that polyester E was used instead of polyester A to obtain a laminated polyester film of 75 μm. The layer configuration was B / E, and the thickness of each layer was 15/60 (μm).

Production Example 15 (Polyester film F5):
In Production Example 11, production was carried out in the same manner as in Production Example 11 except that polyester F was used instead of polyester A to obtain a laminated polyester film of 75 μm. The layer configuration was B / F, and the thickness of each layer was 5/70 (μm).

Production Example 16 (Polyester film F6):
In Production Example 11, production was carried out in the same manner as in Production Example 11 except that polyester G was used instead of polyester A to obtain a laminated polyester film of 75 μm. The layer configuration was B / G, and the thickness of each layer was 5/70 (μm).

Production Example 17 (Polyester film F7):
In Production Example 11, production was conducted in the same manner as in Production Example 11 except that Polyester H was used instead of Polyester A, to obtain a laminated polyester film of 75 μm. The layer configuration was B / H, and the thickness of each layer was 5/70 (μm).

Production Example 18 (Polyester film F8):
In Production Example 11, production was carried out in the same manner as in Production Example 11 except that Polyester I was used instead of Polyester A, to obtain a laminated polyester film of 75 μm. The layer configuration was B / I, and the thickness of each layer was 5/70 (μm).

Production Example 19 (Polyester film F9):
In Production Example 11, an attempt was made in the same manner as in Production Example 11 except that Polyester J was used instead of Polyester A, but a laminated polyester film could not be obtained.

Example 1:
The following release layer (1) was provided on the B layer on the substrate-laminated polyester film F3 (75 μm) obtained from Production Example 9 to obtain a release polyester film.
<Release layer (1)>
The coating composition (adjusted with MEK / toluene mixed solvent (mixing ratio is 1: 1)) having the following release layer composition was applied at a drying temperature of 150 ° C., a drying time of 30 seconds, and a coating amount of 0.1 g / m ² ( A release layer (1) was provided so as to be after drying.
-Release layer composition (A) Ethyl cellulose (X-62-9201A, solid content 10%: manufactured by Shin-Etsu Chemical Co., Ltd.)
60 parts by weight (B) addition reaction silicone based on polydimethylsiloxydiphenylsiloxane (X-62-9201B, solid content 30%: manufactured by Shin-Etsu Chemical Co., Ltd.) 12 parts by weight (C) MQ resin (KS-3800, solid Min 30%, manufactured by Shin-Etsu Chemical Co., Ltd.) 8 parts by weight (D) platinum catalyst (PL-50-T, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.6 parts by weight

Examples 2-6:
A release polyester film was obtained in the same manner as in Example 1 except that the release layer in Example 1 was changed to (2) to (6) in Table 1 below.

Examples 7 and 8:
A release polyester film was obtained in the same manner as in Example 1 except that the substrate-laminated polyester film in Example 1 was changed to F4 and F5, respectively.

Comparative Examples 1-5:
A release polyester film was obtained in the same manner as in Example 1 except that the release layer of Example 1 was as shown in (7) to (11) of Table 2 below.

Comparative Example 6:
A release polyester film was obtained in the same manner as in Example 1 except that the substrate laminated polyester film was F1 and the release layer was (2) in Table 2.

Comparative Example 7:
A release polyester film was obtained in the same manner as in Example 1 except that the substrate laminated polyester film was F2 and the release layer was (2) of Table 2.

Comparative Example 8:
A release polyester film was obtained in the same manner as in Example 1 except that the base material laminated polyester film was F6 and the release layer was (3) of Table 2.

Comparative Example 9:
A release polyester film was obtained in the same manner as in Example 1 except that the base material laminated polyester film was F7 and the release layer was (4) of Table 2.

Comparative Example 10:
A release polyester film was obtained in the same manner as in Example 1 except that the substrate laminated polyester film was F8 and the release layer was (6) of Table 2.

  The evaluation results of the film obtained in each example are summarized in Tables 1 and 2.

  The film of the present invention can be suitably used as a release film used in the ceramic sheet production field.

Claims (5)

Made of polyester at least two layers are laminated by coextrusion, and on at least one surface of a substrate laminated polyester film beam to satisfy the following expressions (1) to (3) simultaneously, cellulose derivatives (A), an addition reaction type silicone ( B), MQ resin (C), and a release polyester film to have a release layer formed from the catalyst,
The ratio of the cellulose derivative (A) in the release layer is 20% by weight or more, and the weight ratio ((C) / (B)) of the addition reaction type silicone (B) and the MQ resin (C) is 0.2. ~ 2,
The release polyester film for green sheets, wherein the base material laminated polyester film satisfies the following formula (5) .
0.53 ≦ [η] ≦ 0.60 (1)
0.1 ≦ d50 ≦ 1 (2)
5 ≦ WA ≦ 20 (3)
(In the above formula, [η] is the intrinsic viscosity of the substrate-laminated polyester film, d50 is the average particle size (μm) of particles contained in at least one layer of the substrate-laminated polyester film, and WA is in the layer of the particles) Content (% by weight)
100 ≦ EBβ + EBγ ≦ 200 (5)
(In the above formula, EBβ and EBγ represent the elongation at break (%) in the β-axis and γ-axis directions of the film, respectively) The release polyester film for green sheets according to claim 1, wherein the initial normal peel force is 400 mN / cm or more, and the change rate of the normal peel force after 6 months is within ± 15%. Release polyester film for green sheet according to claim 1 or 2, characterized in that the substrate laminated polyester film satisfies the following formula (4).
0.03 ≦ Ra ≦ 0.1 (4)
(In the above formula , Ra represents the center line average roughness (μm) of the release layer surface) The release polyester film for green sheets according to any one of claims 1 to 3 , wherein the amount of added particles contained in the polyester on the side where the release layer of the substrate laminated polyester film is provided is less than 1% by weight. The green sheet which has the release polyester film for green sheets of any one of Claims 1-4.